Better in-flight streaming and video-calling might just become more accessible thanks to a project supported by the European Space Agency (ESA). Building upon the success of an experiment for a new type of antenna terminal together with ESA, Viasat – a global leader in satellite communications – now plans to commercialise its new in-flight connectivity solution called Viasat Amara.
Viasat Amara has a dual-beam phased array antenna that provides both better access to video calling (a latency-sensitive use), as well as video streaming such as watching a football match (a bandwidth-sensitive use). This is possible because the antenna can connect to satellites both in low Earth orbit and in geostationary orbit, depending on what is needed. Links using satellites in low Earth orbit have lower latency with minimal communication delays, whereas those with satellites in geostationary orbit have a high bandwidth and so can transmit much more data.
Testing the antenna
Antenna terminal used on a demonstration flight for Viasat, designed and tested within an ESA partnership
The antenna terminal was developed, designed and tested within an ESA partnership, under ESA’s programme of Advanced Research in Telecommunications Systems (ARTES). The experiment, conducted in 2021, consisted of a demonstration flight from Rotterdam in the Netherlands to Payerne in Switzerland. The antenna provided a reliable satellite connection en route, enabling passengers to stream content on Youtube and Netflix, and video call with colleagues on the ground.
The antenna’s design
Visualisation of the arrays of Viasat’s in-flight connectivity antenna
The antenna uses an innovative design known as an electronically steered phased array. Rather than relying on a single large antenna that physically moves to track satellites, it uses many small components. These individual elements coordinate the timing of their signals to have a unified connection, similar to how a stadium wave forms as each person stands up consequently. This mirrors movement and provides not only a faster way to connect, but also the possibility of connecting to two satellites simultaneously.
Viasat’s in-flight solution’s commercial service is expected to begin in 2028. Thanks to its modular technology, the product can be easily incorporated into existing antennas, making it cheaper and easier to incorporate in passenger airlines.
“Phased array antennas are an evolutionary and much needed step towards more energy and space efficient in-flight connectivity solutions, and we are proud to have contributed to Project Aidan – a key milestone that led Viasat to developing Amara. We’re looking forward to next opportunities for cooperation with Viasat, and many other industry partners – for the benefit of all ESA Member States,” said Massimiliano Simeoni, Aidan’s Project Implementation Manager at ESA Connectivity and Secure Communications.
“The Viasat Aera terminal is a key part of Viasat Amara, our next generation in-flight connectivity solution going far beyond fast and free high-speed Wi-Fi,” said Viasat on its Viasat Amara announcement. “Our pioneering mission remains to help our airline customers maximize connectivity’s enormous potential for brand, loyalty, and growth. It’s been great to work with ESA as one of our key partners to help bring it to fruition.”
This antenna development marks the beginning of exciting opportunities for the future of onboard connectivity.
Thank you for liking
You have already liked this page, you can only like it once!
LAWRENCE — According to new research, social media may be a surprisingly reliable source for stock tips … if you know where to look.
“We find that when investors discuss analyst revisions on Twitter, it helps the market better understand and more quickly impound the information in the analyst report,” said Eric Weisbrod, associate professor of accounting at the University of Kansas.
His article titled “Social Media Discussion of Sell-Side Analyst Research: Evidence from Twitter” examines sell-side analysts’ stock recommendation revisions on Twitter, observing increased levels of price discovery during intraday windows with more revision-related tweets. This is especially notable for tweets with more user engagement and those posted by more influential authors.
Eric Weisbrod
Weisbrod’s work is forthcoming in an issue of Review of Accounting Studies.
“Whether it’s on Twitter or WallStreetBets on Reddit or whichever platform, people will post about the profits they’ve been making … or sometimes, humorously, about their losses,” Weisbrod said.
“But for the individuals who are making money, other people see that on their social media feed, and since they would like to experience similar profits, they try to follow these individuals’ advice. It’s similar to any type of celebrity or influencer.”
Co-written by KU doctoral candidate Matt Peterson, Andrew Call of the University of Southern California and Mehmet Kara of the University of Georgia, the research finds that platforms such as Twitter have emerged in this space due to the barriers retail investors face in accessing analysts’ stock recommendation revisions in a timely fashion.
“The common metaphor for Twitter is it’s the digital town square. We find that’s true with respect to this piece of information. When an analyst changes their recommendation, the revision used to be very proprietary to only the clients of the brokerage where the analysts work. But the more times information is discussed in the town square, the more that all investors can incorporate the news,” said Weisbrod, who notes the data for the article was culled prior to July 2023, when Elon Musk took over Twitter and changed its name to X.
One key question is why people make any financial decisions based on social media discussions.
“We’re putting one more data point in this debate that there’s good and bad information on social media, and I think that’s the challenge we all face these days of trying to identify what’s credible and what’s not,” Weisbrod said.
His team found several tests to determine if the information is reliably helpful for investors.
“For example, if there’s a link to an underlying source document that can show this was an analyst report — not just a random bot recommending a stock — that makes it more credible. Or if it’s from a verified account. And since our data is from the original Twitter period, to be verified you actually had to submit documentation. It wasn’t just ‘pay for verification’ like it is now. So if you were a verified public figure and tweeted about an analyst recommendation, then your tweets were more credible,” he said.
The impetus for this story stemmed from a presentation Weisbrod and Peterson attended concerning how viral tweets about earnings were bad for investors.
“We both had been thinking, ‘I wonder if people discuss analyst reports on Twitter? And is that good or bad?’ So the two of us started talking, and it evolved from there,” Weisbrod said.
Since analyst research is typically proprietary, the researchers were unsure how much Twitter discussion they would find. Yet they were able to analyze 50,286 recommendation revisions announced from 2013 to 2020. They observed at least one revision-related tweet during the two trading-day announcement window for 90.1% of all these revisions.
“Brokerages don’t really want their analysts’ research getting out because they want it to be more valuable to their own clients,” he said. “But we didn’t know that the leaks or discussion of these things would be quite so prevalent.”
Weisbrod previously served as an academic fellow in the Office of the Chief Accountant at the U.S. Securities and Exchange Commission in Washington, D.C. The Dallas native came to KU in 2020, where his research focuses on financial data providers and financial analysts.
“There’s a lot of information of questionable credibility on social media. Since we’re in the business school, we mostly think about investment-related social media. Even within that, some people are just pumping and dumping stocks, and it’s hard to know who to trust,” Weisbrod said.
“What we found is one way to capitalize on seeing people discussing a stock on social media. You can trust this more if it references a certified financial analyst, and then maybe this person has actually done their homework instead of just trying to scam you into buying a stock.”
JPMorganChase (NYSE: JPM) officially opened its new global headquarters at 270 Park Avenue, marking a major milestone in its commitment to New York City. Designed to accommodate 10,000 employees and thousands of daily guests, the building offers 2.5 million square feet of flexible workspace, smart technology, and advanced infrastructure for the future of work. With 2.5 times more outdoor space than the previous building – including a public plaza, green spaces, and wider sidewalks – JPMorganChase Tower fosters a vibrant environment for the Midtown community. As the city’s largest all-electric tower, it operates at net zero emissions and delivers exceptional indoor air quality, setting new standards for sustainability, health, and wellness.
Boosting New York City’s economy
JPMorganChase remains one of the city’s largest employers, with the new building housing 10,000 of its 24,000 New York City employees. According to an independent study by Vista Site Selection, the firm contributes $42 billion annually to the city’s economy, supporting an additional 40,000 jobs across local industries. The construction of the new building alone created 8,000 jobs across 40 local unions.
Part of firm’s broader investment in Midtown Manhattan and workspaces globally
The new headquarters at 270 Park represents a major step in JPMorganChase’s ongoing investment in Midtown Manhattan and its global office network. In Midtown, the firm worked closely with the Metropolitan Transportation Authority to significantly improve the neighborhood’s infrastructure across several blocks. The opening of 270 Park also marks the start of renovations at the firm’s 383 Madison Avenue building, directly across the street. Both projects will enhance public spaces with a new plaza on Madison Avenue, wider sidewalks, and improved access to Grand Central Terminal.
Beyond New York, JPMorganChase has invested billions of dollars to renovate and expand offices throughout the U.S. and worldwide, reflecting its commitment to creating modern, collaborative work environments for employees everywhere.
Setting a new standard for office towers
The 60-story skyscraper reimagines the workplace for employees, clients, and the community. Key features include:
2.5 million square feet of dynamic workspace and collaboration areas, including 285,000 square feet of dedicated client entertainment space, powered by smart technology and advanced infrastructure.
Innovative fan column structure and triangular bracing create 2.5 times more public space at street level than the previous building, including wider sidewalks, and a public plaza on Madison Avenue.
Vibrant streetscape and outdoor amenities create a ‘city within a city’ for residents, workers, and visitors.
A welcoming lobby, eight expansive trading floors, a triple-height ‘Exchange’ hub for dining and large gatherings, and a world-class client center at the top.
Touchless journey for employees with more than 50,000 connected devices delivering a seamless, data-driven experience.
Higher ceilings that far exceed typical office standards, along with 50% more communal spaces, and 25% more volume of space per person.
Split elevator core and shuttle elevators enhance connectivity and flexibility.
Column-free floor plates allow for adaptable layouts.
Outdoor terraces with natural plantings and biophilic design elements.
Sustainability
New York City’s largest all-electric skyscraper with net zero operational emissions, 100% powered by renewable energy sourced from a New York State hydroelectric plant.
Designed to achieve LEED Platinum v4 and WELL Health-Safety Rating.
Intelligent building technology uses sensors, AI, and machine learning systems to predict, respond, and adapt to energy needs.
Advanced water storage and reuse systems reduce water usage more than 40%.
Triple-pane glazing on the façade and automatic solar shades connected to HVAC systems for greater energy efficiency.
97% of demolition materials recycled, reused, or upcycled – far exceeding green building standards.
Health and wellness
Double the amount of outside, fresh air and continuous air quality monitoring.
Advanced HVAC filtration systems for cleaner air.
State-of-the-art health and wellness center with fitness areas, yoga/cycling rooms, medical services, mother’s rooms, and meditation spaces.
30% more daylight and circadian lighting for healthier indoor environment.
Enhancing New York City’s skyline and streets with public art
JPMorganChase has commissioned five new artworks from world-class artists that will enrich the cultural fabric of New York City:
A Parallel Nature by Maya Lin: This large-scale artwork is the centerpiece of the new public plaza on Madison Avenue, inspired by the natural bedrock of the city and the rock faces of Central Park.
Celestial Passage by Leo Villareal: This distinct light-based artwork transforms the city’s skyline, illuminating the 1,388-foot building’s crown nightly with gently shifting waves of monochromatic light.
Color Chase One and Color Chase Two by Gerhard Richter: The lobby on Park Avenue features two large-scale, painted works made with interlocking, hard-angled aluminum shapes that are visible to pedestrians and visitors.
Wind Dance by Lord Norman Foster: A 3-D printed column in bronze serves as a centerpiece in the lobby, visible from both Madison and Park Avenues. It replicates outdoor airflow to ensure the flag inside moves in harmony with those outside.
Living Building by Refik Anadol: The lobby’s elevator banks become a vibrant display of light and movement, powered by custom AI models.
Project partners
Foster + Partners served as the lead architect for the building’s design, with Tishman Speyer as the developer manager. Adamson Associate Architects served as the architect of record and executive architect, with Jaros, Baum & Bolles (JB&B) as the mechanical and services engineers. In addition to Foster + Partners, interior spaces were designed by Gensler, Skidmore, Owings & Merrill (SOM), and STUDIOS. Vishaan Chakrabarti, Architect and Founder of Practice for Architecture and Urbanism served as the project’s overall design advisor.
JPMorganChase partnered with experts including Dr. Joseph Allen, Director of Harvard University’s Healthy Buildings program; wellness expert Deepak Chopra; Danny Meyer of Union Square Hospitality Group to create world-class wellness and hospitality experiences.
The construction project was managed by AECOM Tishman, with New York City Constructors overseeing the frame’s installation and Severud Associates serving as the structural engineer. JRM Construction Management, Structure Tone Building Group, and McKissak, Turner and Valez (MTV) performed the fit-out of the interior spaces.
Images and video: Click here to access a full media kit, including images and video.
Official statements
Jamie Dimon, Chairman and CEO of JPMorganChase: “For more than 225 years, JPMorganChase has been deeply rooted in New York City. The opening of our new global headquarters is not only a significant investment in New York, but also a testament to our commitment to our clients and employees worldwide. By creating world-class environments where our employees can thrive, we are strengthening our ability to serve our clients and communities – locally and globally – for generations to come.”
Government official statements
New York State Governor Kathy Hochul:“The official opening of JPMorganChase’s new global headquarters does more than add a signature building to Manhattan’s skyline – it reaffirms New York as the world’s financial capital, built on the strength of our workforce and infrastructure. Even better, 270 Park Avenue delivers benefits beyond its four walls, with critical investments to modernize the Grand Central train shed, ensuring safter, faster commutes for hundreds of thousands of New Yorkers. I commend Jamie Dimon and the JPMorganChase Operating Committee for their steadfast commitment to New York and the men and women for making this vision a reality. There is no better place to do business than New York.”
U.S. Senate Minority Leader Chuck Schumer: “The opening of JPMorganChase’s stunning 270 Park, a spectacular addition Manhattan’s iconic skyline, sends an emphatic message to the world that New York City remains the greatest city on the planet – one where the most brilliant, creative, ambitious, and hardworking people from all around the world come to make their mark. In so doing these employees do so much to create jobs, support countless workers in related industries that power the New York and American economy. I’m excited to see CEO Jamie Dimon put this exclamation point on JPMorganChase’s commitment to New York, and to Gary LaBarbera, Vinnie Alvarez, and all of the union leaders and laborers who made it a reality, not to mention the significant contributions from the City of New York, the MTA and more. In Manhattan, 270 Park will support 10,000 high-skilled employees in good-paying jobs that will have a cascading ripple effect on the entire economic ecosystem of NYC, from the small business owner opening a new café or restaurant to the taxicab driver and fruit stand vendor. Our city is strongest when those with the most invest locally in their community, and 270 Park is a literally shining example of the best version of this. Onward and upward!”
U.S. Representative Jerry Nadler (NY/12): “JPMorganChase’s new worldwide headquarters right here in Manhattan shows a commitment like no other in our great city. This project spurred thousands of union jobs and billions in economic activity and will continue to contribute to our economy and the economic wellbeing of our entire City, State and region. I welcome the opening of JPMorganChase’s new HQ that will continue to cement New York City as the undisputed financial capital of the world.”
New York City Mayor Eric Adams: “As the mayor of the greatest city in the world, I am proud to not only celebrate the opening of JPMorganChase’s new global headquarters in Manhattan but their continued investment in New York City and our people. With this world-class building, JPMorganChase will give over 10,000 workers a high-quality home, raise the bar for sustainability, and open even more public space for New Yorkers to enjoy. Four years ago, major employers and office workers were fleeing our city; now, thanks to our administration’s relentless focus on public safety and growing our economy, jobs are at a record high and businesses from start-ups to global titans are opening new offices block by block. This transformation would not be possible without partners like JPMorganChase, who are proving, once again, that New York City is open for business.”
Manhattan Borough President Mark Levine: “270 Park Avenue was one of the most complicated construction projects in recent memory, including significant transit upgrades. Its completion is a milestone moment for New York City, solidifying Midtown’s comeback post-pandemic as one of world’s leading economic hubs. I congratulate JPMorganChase on this enormous accomplishment and look forward to their solidified role as a major employer in New York City.”
New York State Senator Liz Krueger: “I am very pleased to see 270 Park – the first new office tower built under the East Midtown Rezoning – open for business. Not only does this building bring brand new Class A office space to East Midtown, but it also demonstrates the viability and the benefits of all-electric construction on a massive scale. Combined with the community benefits realized through the design and the funds resulting from air rights transfers, this project is a big win for Manhattan.”
New York State Senator Brad Hoylman-Sigal:“JPMorganChase has reaffirmed Manhattan’s position as the international capital of finance with their soaring, state-of-the-art global headquarters location at 270 Park Avenue. In addition to being the new home for over 10,000 employees, this gleaming new tower is an enormous boost to the local economy, having created 8,000 construction jobs from 40 local unions and triggering additional economic activity of $2.6 billion for New York City and $3.6 billion for New York State overall. I’m grateful to the leadership of JPMorganChase, the Building and Construction Trades Council of Greater New York, and my partners in government for their help making this project possible.”
New York State Assemblymember Alex Bores: “Today’s ribbon cutting at 270 Park Avenue honors the New Yorkers who built it. This project showcases the ingenuity and creativity that keep New York City leading the way in building the future. Thank you to the more than 8,000 union tradespeople across 40 local unions who made it possible.”
New York City Councilmember Keith Powers:“The new headquarters of JPMorganChase in the heart of my district will be a massive economic driver in New York City. The building is leading the way on sustainability and public space, and provides an example for future commercial development. I’m thrilled to see it open today, and to welcome the 10,000 employees who will now be spending their workdays in my district.”
Gary LaBarbera, President of the Building and Construction Trades Council of Greater New York:“The grand opening of JPMorganChase’s global headquarters represents an impeccable milestone for New York City and the tradesmen and tradeswomen who benefitted from the union construction careers this project created. Now, thousands of hardworking New Yorkers have been granted the opportunity to pursue the middle class and support their families, all while acting as a driving force behind this historical investment in our city and the economic stimulus it will create. We congratulate JPMorganChase on their new home at 270 Park Avenue and commend our highly-skilled members who played a pivotal role in getting this modern, cutting-edge, best-in-class, building across the finish line.”
Project partner statements
Norman Foster, Founder and Executive Chairman, Foster + Partners:“This new all electric tower is hydro powered to minimize its carbon footprint. The unique cantilevered structure, clad in bronze, delivers two and a half times the amount of public space at the base, including a garden, than its predecessor. The unparalleled range of venues and leisure activities, couple to tall spaces with generous natural light and high levels of fresh filtered air (twice that of building codes) combine to set new standards of wellbeing. It is the workplace of the future designed for today.”
Rob Speyer, CEO of Tishman Speyer:“Since day one, Jamie Dimon and his leadership team have demonstrated an unwavering commitment to developing the greatest office tower in the world. Every element of the building was crafted with JPMorganChase’s clients and people in mind. 270 Park is a building all New Yorkers can be proud of.”
John Kovacs, Chief Operating Officer, AECOM Tishman:“We are honored to have been entrusted by JPMorganChase to build their awe-inspiring new headquarters at 270 Park Avenue. The sheer complexity of this project, from its all-electric infrastructure to its intricate structural system to its remarkable amenities and green spaces, showcases the creativity and capabilities of the entire design and construction team, as well as the thousands of skilled tradespeople who helped take 270 Park Avenue from concept to reality. Throughout our 127-year history, AECOM Tishman has built numerous projects that have shaped the New York City skyline, and we are thankful to JPMorganChase for allowing us to continue that tradition and for making this investment in New York’s future.”
Rocco Giannetti, Regional Managing Principal, Gensler:“New York City is a magnetic city, and the new JPMorgan Chase headquarters at 270 Park emphasizes the magnitude of excellence that pulls people and leading companies to Manhattan and keeps them here. Gensler is pleased to have contributed to the design and execution of the dynamic and multifaceted workplace, client centers, and amenities of the headquarters, where prioritizing social, functional, and restorative spaces will serve JPMorganChase’s employees and clients for decades to come.”
Walter Mehl, Managing Partner, JB&B:“The JPMorganChase Tower at 270 Park Avenue is one of the greatest accomplishments of our time: the construction of a 60-story state-of-the-art skyscraper that, once completed, will be New York City’s largest all-electric building. With its net-zero operational emissions, unsurpassed indoor air quality, and 21st century infrastructure, the building not only radically reimagines the urban workplace but also represents a quantum leap in the evolution of design and engineering. The JB&B team was honored to be part of this historic building, reaching new heights in sustainability and electrification, and truly engineering the building of the future.”
About JPMorganChase
JPMorganChase serves more than 4 million New York City consumers and small businesses through 290 Chase branches across all five boroughs, with nearly 40 branches offering free workshops, skills training, and support for small businesses. Since 2019, the firm has contributed more than $123 million to local nonprofits, helping address housing affordability, supporting small businesses, and creating jobs.
To learn more about JPMorganChase’s impact in New York City, please visit: https://www.jpmorganchase.com/communities/new-york
JPMorgan Chase & Co. (NYSE: JPM) is a leading financial services firm based in the United States of America (“U.S.”), with operations worldwide. JPMorganChase had $4.6 trillion in assets and $360 billion in stockholders’ equity as of September 30, 2025. The Firm is a leader in investment banking, financial services for consumers and small businesses, commercial banking, financial transaction processing and asset management. Under the J.P. Morgan and Chase brands, the Firm serves millions of customers in the U.S., and many of the world’s most prominent corporate, institutional and government clients globally. Information about JPMorgan Chase & Co. is available at www.jpmorganchase.com.
The CMA’s merger remedies guidance plays a key role in determining whether transactions that raise antitrust concerns can be allowed to proceed on the basis of commitments offered by the merging parties. As such, the consultation and Draft Guidance is an important step in wide-ranging ongoing reforms to the UK merger control process, to implement the CMA’s “4Ps” agenda. This seeks to encourage “pace, predictability, proportionality and process” across the CMA’s portfolio of work.
The overall message of the consultation will be welcome to parties involved in M&A activity. The CMA stresses that, in transactions raising antitrust concerns, it wants to work constructively with businesses to identify as quickly as possible whether there is an effective and proportionate remedy that will enable them to get on with implementing the transaction and running their businesses.
The consultation and Draft Guidance include a number of changes that should contribute to this objective. However, much will depend on how any final revised guidance is applied in practice, as well as the outcome of future consideration of the CMA’s approach to efficiencies.
We contributed to the earlier review (our response is here) and will be submitting a response to the current consultation. In the meantime, we summarise below five key (provisional) takeaways for merging parties.
1. Behavioural remedies are more likely to make the grade
The CMA retains its current position that structural divestments are more likely to be effective in addressing concerns than behavioural remedies (under which merger parties make commitments as to their future behaviour, rather than selling a business). However, the Draft Guidance shows a clear softening in the CMA’s stance towards behavioural remedies.
Under the proposals, the CMA is now more likely to accept behavioural fixes in wider range of circumstances. Previously, the CMA’s guidance envisaged accepting such remedies only where: antitrust concerns had a limited duration; the remedies would preserve substantial “relevant customer benefits” (see below); and/or a structural remedy is not feasible. Now, the CMA proposes that it is more likely to accept such remedies where:
The remedy has a limited duration.
There is an industry regulator that can monitor and enforce the commitments, or the parties appoint a monitoring trustee to fulfil this role.
The market is transparent (enabling customers, rivals and suppliers to identify and report non-compliance) or sufficiently mature and stable (meaning less risk that the remedy becomes ineffective).
The remedy aligns with existing commercial practices/norms.
In a further welcome move, the CMA will remove its presumption against behavioural remedies being accepted at phase 1. However, this comes with the important qualification that they will still need to meet a demanding “clear-cut” standard, which the CMA considers is more likely to be met by structural remedies.
2. Remedies can be used to lock-in pro-competitive efficiencies
The CMA acknowledges that some parties may claim that a merger will result in efficiencies that strengthen competition in the relevant market. However, there may be doubts as to whether they will deliver these efficiencies in full. The Draft Guidance describes how remedies can be used to secure the parties’ efficiency commitments.
This proposed change reflects the CMA’s experience in Vodafone/Three, where the central plank of the remedies it accepted was a commitment by the merging parties to deliver their network investment plans (which the CMA considered could enhance competition but doubted would be delivered in full).
It signals a thawing of the authority’s approach to assessing rivalry-enhancing efficiency claims in merger reviews. However, the Draft Guidance only covers the interaction between merger remedies and efficiency claims—the CMA says it will consider its substantive approach to efficiencies more generally in due course.
3. Customer benefits may impact remedy choice and design
Relevant customer benefits take the form of lower prices, higher quality, greater choice or increased innovation. They can result from a merger but do not necessarily need to be achieved through increased competition in the markets where the antitrust concerns arise. The bar for proving them is high, and they have been rarely accepted by the CMA.
While not proposing to lower the evidentiary burden, the CMA aims to clarify how remedies can be selected (or even modified) to ensure that any customer benefits are preserved.
4. Complex divestments might be possible with clear evidence and risk mitigation measures
Divestment of an existing business will remain preferable to a carve-out divestment (i.e., the sale of part of a business or collection of assets) or other complex structural remedies such as an IP divestiture.
But the Draft Guidance gives parties more clarity around the types of evidence it will take into account when assessing carve-out remedies and the ways in which the risks of complex divestments can be mitigated. These include use of upfront buyers, divestiture/monitoring trustees, or a “fall-back remedy” for situations where the complex divestment is unsuccessful.
In another significant move, the CMA is proposing to clarify its stance on divestments in transactions involving local markets at phase 1.
In these cases, the CMA often sets a threshold or “decision rule” for when antitrust concerns arise, e.g., by using a “filter” to assess competition around specific locations and an appropriate intervention threshold (such as market share).
The CMA is clarifying that, at phase 1, it may be enough for the merged entity to divest sites to bring it below the intervention threshold—even if this does not eliminate the entire local overlap (which was an approach that could lead to a far higher number of local divestments at phase 1). The CMA will require robust evidence to show that such divestments will be effective but, if demonstrated, this could bridge the often-significant delta in number of local divestments required to solve antitrust concerns at phase 1, saving parties from a lengthy phase 2 process.
5. Early engagement with the CMA increases the chance of acceptance (and a monitoring trustee/industry expert might help)
The CMA has already proposed and is currently finalising improvements to its merger review processes to implement its 4Ps framework. But it plans to do more—especially at phase 1—to enhance the remedies process.
Most of these changes are designed to encourage and facilitate early discussion of remedies, with the CMA explicitly noting that the earlier parties start engaging with the CMA on remedies, the more likely it is that the phase 1 standard for acceptance of remedies will be met. The CMA signals that it will be open to early “without prejudice” discussions during phase 1 (even in pre-notification) and at the early stages of phase 2.
The CMA also encourages (but notes it cannot require) merging parties to consider appointing a monitoring trustee or industry expert to assist with remedy discussions. Parties would need to balance the cost of this against the possible benefits—the CMA suggests it could help its assessment of the remedy proposal, give additional comfort that the commitments will be effective, and enable a quicker decision.
Other changes are afoot
As noted above, the proposed changes form part of a wider programme of work. This arguably involves the most significant shift in UK merger control policy since the CMA was created. Some other key developments:
New timing KPIs for pre-notification and straightforward phase 1 reviews, as well as other proposed changes to the phase 1 process, aimed at increasing pace and boosting engagement between the CMA and merging parties.
Proposals to clarify aspects of how the CMA will apply the “material influence” and “share of supply” jurisdictional tests. These concepts are notoriously expansive, giving the CMA very broad jurisdictional reach, and have faced heavy criticism. Government proposals on possible legislative revisions are also expected.
A push—following the Government’s “strategic steer” to the CMA—to de-prioritise global deals that concern global markets (with no UK-specific impact) and where action by non-UK regulators can be expected to address any issues arising in markets in the UK.
A discussion paper on “scale-ups”, exploring how competition policy can help (and not hinder) UK start-ups from becoming “superstar firms” competing in global markets (a focus of UK government industrial strategy). This raises a number of potential ideas, ranging from relatively straightforward measures the CMA itself could take (like further guidance on beneficial collaboration between businesses in compliance with competition law) through to radical measures requiring government intervention (such as factoring the nationality of an acquirer into a review in certain circumstances and/or allowing the government to trigger a review screening deals for their impact on the UK’s strategic resilience).
Beyond the UK: a similar shift?
The CMA does not stand alone in signalling a more permissive approach to merger remedies.
As we discussed in our recent alert, the U.S. antitrust agencies are also embracing a more pragmatic, transparent and flexible stance, moving away from the de facto “no remedies” approach under the Biden administration.
The merger remedies landscape is evolving rapidly. We can help you navigate it and will keep you updated as approaches crystalise in the UK and elsewhere.
The governor of the Bank of England, Andrew Bailey, has warned recent events in US private credit markets have worrying echoes of the sub-prime mortgage crisis that kicked off the global financial crash of 2008.
Appearing before a House of Lords committee, the governor said it was important to have the “drains up” and analyse the collapse of two leveraged US firms, First Brands and Tricolor, in case they are not isolated events but “the canary in the coalmine”.
“Are they telling us something more fundamental about the private finance, private asset, private credit, private equity sector, or are they telling us that in any of these worlds there will be idiosyncratic cases that go wrong?” he asked.
The Bank of England governor, Andrew Bailey. Photograph: Alastair Grant/Reuters
“I think that is still a very open question; it’s an open question in the US.”
He added: “I don’t want to sound too foreboding, but the added reason this question is important is if you go back to before the financial crisis when we were having this debate about sub-prime mortgages in the US, people were telling us, ‘No it’s too small to be systemic, it’s idiosyncratic’… That was the wrong call.”
Bailey said the complex nature of some of the financial engineering in use in the private credit markets gave cause for concern.
“We certainly are beginning to see, for instance what used to be called slicing and dicing and tranching of loan structures going on, and if you were involved before the financial crisis and during it, alarm bells start going off at that point,” he told peers.
“That stuff was a feature of the financial crisis, so that’s another reason why we’ve got to use these cases as another reason to have more drains up, frankly.”
Deputy Bank governor Sarah Breeden, appearing alongside Bailey, said the Bank would be carrying out a war game exercise in these markets, to test the linkages between private credit and other sectors.
She underlined some of the concerns about the private credit sector. “It’s about high leverage, it’s about opacity, it’s about complexity and it’s about weak underwriting standards.
skip past newsletter promotion
after newsletter promotion
“Those are things that we were talking about in the abstract as a source of vulnerability in this bit of the financial system, and those appear to have been at play in the context of these two defaults.”
The collapse of car parts firm First Brands and auto lender Tricolor prompted concern on Wall Street, with the JP Morgan chief executive, Jamie Dimon, comparing them to “cockroaches”, and saying that more could emerge.
The International Monetary Fund’s global financial stability review last week highlighted concerns about the close connections between private credit markets and mainstream banks – and the IMF’s managing director, Kristalina Georgieva, said it was the issue that kept her awake at night.
Dobson R, Giovannoni G. Multiple sclerosis – a review. Eur J Neurol. 2019;26(1):27–40. https://doi.org/10.1111/ene.13819.
Article
PubMed
Google Scholar
Lanz TV, Brewer RC, Ho PP, Moon JS, Jude KM, Fernandez D, et al. Clonally expanded B cells in multiple sclerosis bind EBV EBNA1 and glialcam. Nature. 2022;603(7900):321–7. https://doi.org/10.1038/s41586-022-04432-7.
Article
PubMed
PubMed Central
Google Scholar
Bjornevik K, Münz C, Cohen JI, Ascherio A. Epstein–Barr virus as a leading cause of multiple sclerosis: mechanisms and implications. Nat Rev Neurol. 2023;19(3):160–71. https://doi.org/10.1038/s41582-023-00775-5.
Article
PubMed
Google Scholar
Morandi E, Tanasescu R, Tarlinton RE, Constantinescu CS, Zhang W, Tench C, et al. The association between human endogenous retroviruses and multiple sclerosis: A systematic review and meta-analysis. PLoS ONE. 2017;12(2):e0172415. https://doi.org/10.1371/journal.pone.
Article
PubMed
PubMed Central
Google Scholar
Küry P, Nath A, Créange A, Dolei A, Marche P, Gold J, et al. Human endogenous retroviruses in neurological diseases. Trends Mol Med. 2018;24(4):379–94. https://doi.org/10.1016/j.molmed.2018.02.007.
Article
PubMed
PubMed Central
Google Scholar
Nevalainen T, Autio-Kimura A, Hurme M. Human endogenous retrovirus W in multiple sclerosis: transcriptional activity is associated with decline in oligodendrocyte proportions in the white matter of the brain. J Neurovirol. 2024;30(4):393–405. https://doi.org/10.1007/s13365-024-01208-9.
Article
PubMed
PubMed Central
Google Scholar
Gruchot J, Reiche L, Werner L, Herrero F, Schira-Heinen J, Meyer U, et al. Molecular dissection of HERV-W dependent microglial- and astroglial cell polarization. Microbes Infect. 2025;27(5–6):105382. https://doi.org/10.1016/j.micinf.2024.
Article
PubMed
Google Scholar
Kremer D, Gruchot J, Weyers V, Oldemeier L, Gottle P, Healy L, et al. PHerv-w envelope protein fuels microglial cell-dependent damage of myelinated axons in multiple sclerosis. Proc Natl Acad Sci U S A. 2019;116(30):15216–25. https://doi.org/10.1073/pnas.1901283116.
Article
PubMed
PubMed Central
Google Scholar
Gruchot J, Lewen I, Dietrich M, Reiche L, Sindi M, Hecker C, et al. Transgenic expression of the HERV-W envelope protein leads to polarized glial cell populations and a neurodegenerative environment. Proc Natl Acad Sci U S A. 2023;120(38):e2308187120. https://doi.org/10.1073/pnas.
Article
PubMed
PubMed Central
Google Scholar
Charvet B, Pierquin J, Brunel J, Gorter R, Quetard C, Horvat B, et al. Human endogenous retrovirus type W envelope from multiple sclerosis demyelinating lesions shows unique solubility and antigenic characteristics. Virol Sin. 2021;36(5):1006–26. 10.7/s12250-021-00372-0.
Article
PubMed
PubMed Central
Google Scholar
Perron H, Germi R, Bernard C, Garcia-Montojo M, Deluen C, Farinelli L, et al. Human endogenous retrovirus type W envelope expression in blood and brain cells provides new insights into multiple sclerosis disease. Mult Scler. 2012;18(12):1721–36. 10.177/1352458512441381.
Article
PubMed
PubMed Central
Google Scholar
Ruberto S, Domınguez-Mozo MI, Garcıa-Martınez MA, Cossu D, Sechi LA, Alvarez-Lafuente R. Immune response profiling of HERV-W envelope proteins in multiple sclerosis: potential biomarkers for disease progression. Front Immunol. 2025;15:1505239. https://doi.org/10.3389/fimmu.2024.
Article
PubMed Central
Google Scholar
Mameli G, Poddighe L, Mei A, Uleri E, Sotgiu S, Serra C, et al. Expression and activation by Epstein Barr virus of human endogenous retroviruses-W in blood cells and astrocytes: inference for multiple sclerosis. PLoS ONE. 2012;7(9):e44991. https://doi.org/10.1371/journal.pone.0044991.
Article
PubMed
PubMed Central
Google Scholar
Mameli G, Madeddu G, Mei A, Uleri E, Poddighe L, Delogu LG, et al. Activation of MSRV-type endogenous retroviruses during infectious mononucleosis and Epstein-Barr virus latency: the missing link with multiple sclerosis? PLoS ONE. 2013;8(11):e78474. https://doi.org/10.1371/journal.pone.0078474.
Article
PubMed
PubMed Central
Google Scholar
Ebrahimkhani S, Vafaee F, Young PE, Hur SSJ, Hawke S, Devenney E, et al. Exosomal microrna signatures in multiple sclerosis reflect disease status. Sci Rep. 2017;7(1):14293. https://doi.org/10.1038/s41598-017-14301-3.
Article
PubMed
PubMed Central
Google Scholar
Palazzo C, Asci I, Russo S, Buccoliero C, Mangialardi V, Abbrescia P, et al. Circulating exosomes with unique lipid signature in relapsing remitting multiple sclerosis. Front Cell Neurosci. 2025;19:1613618. https://doi.org/10.3389/fncel.2025.
Article
PubMed
PubMed Central
Google Scholar
D’Anca M, Fenoglio C, Buccellato FR, Visconte C, Galimberti D, Scarpini E. Extracellular vesicles in multiple sclerosis: role in the pathogenesis and potential usefulness as biomarkers and therapeutic tools. Cells. 2021;10(7):1733. https://doi.org/10.3390/cells10071733.
Article
PubMed
PubMed Central
Google Scholar
Teow SY, Liew K, Khoo AS, Peh SC. Pathogenic role of exosomes in Epstein-Barr virus (EBV)-associated cancers. Int J Biol Sci. 2017;13(10):1276–86. https://doi.org/10.7150/ijbs.19531.
Article
PubMed
PubMed Central
Google Scholar
Meier UC, Cipian RC, Karimi A, Ramasamy R, Middeldorp JM. Cumulative roles for Epstein-Barr virus, human endogenous retroviruses, and human herpes virus-6 in driving an inflammatory cascade underlying MS pathogenesis. Front Immunol. 2021;12:757302. https://doi.org/10.3389/fimmu.2021.
Article
PubMed
PubMed Central
Google Scholar
Mrad MF, Saba ES, Nakib L, Khoury SJ. Exosomes from subjects with multiple sclerosis express EBV-derived proteins and activate monocyte-derived macrophages. Neurol Neuroimmunol Neuroinflamm. 2021;8(4):e1004. 10.212/NXI.0000000000001004.
Article
PubMed
PubMed Central
Google Scholar
Thompson AJ, Banwell BL, Barkhof F, Carroll WM, Coetzee T, Comi G, et al. Diagnosis of multiple sclerosis: 2017 revisions of the McDonald criteria. Lancet Neurol. 2018;17(2):162–73. https://doi.org/10.1016/S474-4422(17)30470-2.
Article
PubMed
Google Scholar
Kremer D, Forster M, Schichel T, Gottle P, Hartung HP, Perron H, et al. The neutralizing antibody GNbAC1 abrogates HERV-W envelope protein-mediated oligodendroglial maturation Blockade. Mult Scler. 2015;21(9):1200–3. 10.177/1352458514560926.
Article
PubMed
Google Scholar
Hartung HP, Derfuss T, Cree BA, Sormani MP, Selmaj K, Stutters J, et al. Efficacy and safety of Temelimab in multiple sclerosis: results of a randomized phase 2b and extension study. Mult Scler. 2022;28(3):429–40. https://doi.org/10.1177/13524585211024997.
Article
PubMed
Google Scholar
Curtin F, Champion B, Davoren P, Duke S, Ekinci EI, Gilfillan C, et al. A safety and pharmacodynamics study of temelimab, an antipathogenic human endogenous retrovirus type W envelope monoclonal antibody, in patients with type 1 diabetes. Diabetes Obes Metab. 2020;22(7):1111–21. 10./dom.14010.
Article
PubMed
Google Scholar
Simula ER, Jasemi S, Cossu D, Fais M, Cossu I, Chessa V, et al. Human endogenous retroviruses as novel therapeutic targets in neurodegenerative disorders. Vaccines. 2025;13(4):415. https://doi.org/10.3390/vaccines13040415.
Article
PubMed
PubMed Central
Google Scholar
Chen J, Foroozesh M, Qin Z. Transactivation of human endogenous retroviruses by tumor viruses and their functions in virus-associated malignancies. Oncogenesis. 2019;8(1):6. https://doi.org/10.1038/s41389-018-0114-y.
Article
PubMed
PubMed Central
Google Scholar
Brütting C, Stangl G, Staege M, Vitamin D. Epstein-Barr virus, and endogenous retroviruses in multiple sclerosis – facts and hypotheses. J Integr Neurosci. 2021;20(1):233–8. https://doi.org/10.31083/j.jin.2021.01.392.
Article
PubMed
Google Scholar
Latifi T, Zebardast A, Marashi SM. The role of human endogenous retroviruses (HERVs) in multiple sclerosis and the plausible interplay between HERVs, Epstein-Barr virus infection, and vitamin D. Mult Scler Relat Disord. 2022;57:103318. https://doi.org/10.1016/j.msard.2021.
Article
PubMed
Google Scholar
Gottle P, Schichel K, Reiche L, Werner L, Zink A, Prigione A, et al. TLR4 associated signaling disrupters as a new means to overcome HERV-W envelope-mediated myelination deficits. Front Cell Neurosci. 2021;15:777542. https://doi.org/10.3389/fncel.2021.
Article
PubMed
PubMed Central
Google Scholar
Osaid Z, Haider M, Hamoudi R, Harati R. Exosomes interactions with the blood–brain barrier: implications for cerebral disorders and therapeutics. Int J Mol Sci. 2023;24(21):15635. https://doi.org/10.3390/ijms242115635.
Article
PubMed
PubMed Central
Google Scholar
Gimenez-Orenga K, Oltra E. Human endogenous retrovirus as therapeutic targets in neurologic disease. Pharmaceuticals (Basel). 2021;14(6):495. https://doi.org/10.3390/ph14060495.
Article
PubMed
Google Scholar
Adler GL, Le K, Fu Y, Kim WS. Human endogenous retroviruses in neurodegenerative diseases. Genes. 2024;15(6):745. https://doi.org/10.3390/genes15060745.
Article
PubMed
PubMed Central
Google Scholar
Bhetariya PJ, Kriesel JD, Fischer KF. Analysis of human endogenous retrovirus expression in multiple sclerosis plaques. J Emerg Dis Virol. 2017;3(2). https://doi.org/10.16966/2473-1846.133.
Moyes DL, Goris A, Ban M, Compston A, Griffiths DJ, Sawcer S, et al. HERV-K113 is not associated with multiple sclerosis in a large family-based study. AIDS Res Hum Retroviruses. 2008;24(3):363–5. https://doi.org/10.1089/aid.2007.0196.
Article
PubMed
Google Scholar
Brudek T, Christensen T, Aagaard L, Petersen T, Hansen HJ, Møller-Larsen A. B cells and monocytes from patients with active multiple sclerosis exhibit increased surface expression of both HERV-H Env and HERV-W Env, accompanied by increased seroreactivity. Retrovirology. 2009;6:104. https://doi.org/10.1186/742-4690-6-104.
Article
PubMed
PubMed Central
Google Scholar
Laska MJ, Brudek T, Nissen KK, Christensen T, Moller-Larsen A, Petersen T, et al. Expression of HERV-Fc1, a human endogenous retrovirus, is increased in patients with active multiple sclerosis. J Virol. 2012;86(7):3713–22. https://doi.org/10.1128/JVI.06723-11.
Article
PubMed
PubMed Central
Google Scholar
Censi ST, Mariani-Costantini R, Granzotto A, Tomassini V, Sensi SL. Endogenous retroviruses in multiple sclerosis: A network-based etiopathogenic model. Ageing Res Rev. 2024;99:102392. https://doi.org/10.1016/j.arr.2024.
Article
PubMed
Google Scholar
Ruberto S, Cossu D, Sechi LA. Correlation between antibodies against the pathogenic pHERV-W envelope protein and the inflammatory phase of multiple sclerosis. Immunology. 2024;171(2):270–6. https://doi.org/10.1111/imm.13712.
Article
PubMed
Google Scholar
Lyu L, Li Q, Wang C. EBV latency programs: molecular and epigenetic regulation and its role in disease pathogenesis. J Med Virol. 2025;97(7):e70501. https://doi.org/10.1002/jmv.
Article
PubMed
PubMed Central
Google Scholar
Aarts SABM, Seijkens TTP, Dorst KJFv, Dijkstra CD, Kooij G, Lutgens E. The CD40–CD40L dyad in experimental autoimmune encephalomyelitis and multiple sclerosis. Front Immunol. 2017;8:1791. https://doi.org/10.3389/fimmu.2017.01791.
Article
PubMed
PubMed Central
Google Scholar
Vermersch P, Wagner D, Mars LT, Noelle R, Giovannoni G. Inhibiting CD40 ligand in multiple sclerosis: a review of emerging therapeutic potential. Curr Treat Options Neurol. 2025;27:7. https://doi.org/10.1007/s11940-024-00818-2.
Article
Google Scholar
Orian JM, D’Souza CS, Kocovski P, Krippner G, Hale MW, Wang X, et al. Platelets in multiple sclerosis: early and central mediators of inflammation and neurodegeneration and attractive targets for molecular imaging and site-directed therapy. Front Immunol. 2021;12:620963. https://doi.org/10.3389/fimmu.2021.
Article
PubMed
PubMed Central
Google Scholar
Burnouf T, Walker TL. The multifaceted role of platelets in mediating brain function. Blood. 2022;140(8):815–27. https://doi.org/10.1182/blood.2022015970.
Article
PubMed
PubMed Central
Google Scholar
Brudek T, Christensen T, Petersen T, Møller-Larsen A. Expression of HERV-H/W Env epitopes on PBMCs from MS patients with active disease. Retrovirology. 2011;8(Suppl 1):A210. https://doi.org/10.1186/742-4690-8-S1-A210.
Article
PubMed Central
Google Scholar
Chunder R, Schropp V, Kuerten S. B cells in multiple sclerosis and virus-induced neuroinflammation. Front Neurol. 2020;11:591894. https://doi.org/10.3389/fneur.2020.
Article
PubMed
PubMed Central
Google Scholar
Garcia-Montojo M, Rodríguez-Martín E, Ramos-Mozo P, Ortega-Madueño I, Domínguez-Mozo M, Arias-Leal A, et al. Syncytin‐1/HERV‐W envelope is an early activation marker of leukocytes and is upregulated in multiple sclerosis patients. Eur J Immunol. 2020;50(5):685–94. https://doi.org/10.1002/eji.201948423.
Article
PubMed
Google Scholar
Banks WA, Sharma P, Bullock KM, Hansen KM, Ludwig N, Whiteside TL. Transport of extracellular vesicles across the Blood-brain barrier: brain pharmacokinetics and effects of inflammation. Int J Mol Sci. 2020;21(12):4407. https://doi.org/10.3390/ijms21124407.
Article
PubMed
PubMed Central
Google Scholar
Gjelstrup MC, Stilund M, Petersen T, Møller H, Petersen EL, Christensen T. Subsets of activated monocytes and markers of inflammation in incipient and progressed multiple sclerosis. Immunol Cell Biol. 2017;96(2):160–74. https://doi.org/10.1111/imcb.025.
Article
PubMed
PubMed Central
Google Scholar
Ferreira-Atuesta C, Reyes S, Giovanonni G, Gnanapavan S. The evolution of neurofilament light chain in multiple sclerosis. Front Neurosci. 2021;15:642384. https://doi.org/10.3389/fnins.2021.
Article
PubMed
PubMed Central
Google Scholar
Virata MCA, Catahay JA, Lippi G, Henry BM. Neurofilament light chain: a biomarker at the crossroads of clarity and confusion for gene-directed therapies. Neurodegener Dis Manag. 2024;14(6):227–39. https://doi.org/10.1080/17582024.2024.2421738.
Article
Google Scholar
Steffen F, Uphaus T, Ripfel N, Fleischer V, Schraad M, Gonzalez-Escamilla G, et al. Serum neurofilament identifies patients with multiple sclerosis with severe focal axonal damage in a 6-year longitudinal cohort. Neurol Neuroimmunol Neuroinflamm. 2023;10(1):e200055. https://doi.org/10.1212/NXI.0000000000200055.
Article
PubMed
Google Scholar
Freedman MS, Abdelhak A, Bhutani MK, Freeman J, Gnanapavan S, Hussain S, et al. The role of serum neurofilament light (sNfL) as a biomarker in multiple sclerosis: insights from a systematic review. J Neurol. 2025;272(6):400. https://doi.org/10.1007/s00415-025-13093-1.
Nine male patients were enrolled during January 2019 to September 2019. Due to the COVID-19 pandemic, study participation was incomplete. Pre-COVID pandemic onset (March 2020), 80.1% of the expected 171 visits were attended (including baseline visits). Post-COVID pandemic, 19.7% of the 458 scheduled visits were attended. The cognitive assessments DAS-II and VABS-3 were performed at baseline only. All other assessments had follow-up visits completed at varying time points (Supplementary Table 1).
Study population and genetic analysis results
We included eight pediatric males and one adult male from the USA, comprising eight families. The characteristics of the study population are summarized in Table 1. Nonsense mutations occurred in six patients (66%) and three patients (33%) had deletions (Table 2).
Table 1 Characteristics of the study cohort, n = 9
Table 2 Genetic screening results for the nine patients
Patient reported outcome measures
PCQLI
Patient responses
Seven of eight pediatric patients had baseline PCQLI responses (88%, n = 7), of which seven had follow-up responses (100%, n = 7). The baseline mean for the Disease Impact subscale was 25.6 ± 6.0. The mean follow-up time was 26.6 months for both patient and parent responses (see all responses in Supplementary Table 2). At last follow up, four patients (57%, n = 4) reported lower Disease Impact scores. For the Psychosocial Impact Score, the mean at baseline was 28.9 ± 7.5. At last follow-up, three patients (43%, n = 3) reported lower scores. For the Total Score, the mean was 54.5 ± 10.5 at baseline. At last follow-up, four patients (57%, n = 4) reported lower total scores.
Parent responses
For the parents, there were eight baseline responses (100%, n = 8), of which seven had follow-up responses (88%, n = 7). Mean follow-up time was 26.6 months. The baseline mean for Disease Impact was 23.8 ± 6.9, with three parents (43%, n = 3) reporting lower scores for their children at last follow up. Mean Psychosocial Impact score at baseline was 28.9 ± 9.6, with five parents (71%, n = 5) reporting lower scores at last follow-up. Finally, the mean Total Score was 52.8 ± 14.9 at baseline, and four parents (57%, n = 4) reported lower total scores for their children at last follow up. The mean scores can be visualized for children and parents in Fig. 1. Notably, average difference between patient and parent Total Scores were 9.1 ± 7.9 and concordance in longitudinal improvements or worsening of scores over time between patients and parents was 75% (n = 9).
Fig. 1
Average subscale and total scores for the Pediatric Cardiac Quality of Life Inventory (PCQLI) across the cohort. For Disease Impact and Psychosocial Impact subscales, 50 is the maximum score (100 for Total Score). The mean follow-up time is 26.6 months. The error bars are the mean and standard deviations for each subgroup
PQLQ
The average scores for the subscales of the PQLQ can be found in Table 3 (see all responses in Supplementary Table 3). Both patients and their parents responded to this. The max score for all subscales was 100. The mean follow-up time was 28.3 months. Figure 2 shows the scores for physical, emotional, social, and school functioning.
Table 3 Average subscale and total scores for the pediatric quality of life questionnaire
Fig. 2
Average scores for the dimensions of the Pediatric Quality of Life Questionnaire (PQLQ). The inventory is filled out by both patients and parents. The parents score their children as functioning worse than the patients personally score themselves. The composite scores total scores are not shown on this radar plot (Table 3). Error bars are not included here in order to maintain visibility. The mean follow-up time was 28.3 months
Patient responses
Six of eight pediatric patients had baseline responses (75%, n = 6), of which five patients had follow-up responses (83%, n = 5). For the physical health summary score, which is equal to the physical functioning score, the baseline mean was 50.0 ± 6.3; two patients (40%, n = 2) reported lower physical health summary scores at follow-up. For the psychosocial health summary score, the baseline mean was 55.3 ± 24.7; one patient (17%, n = 1) reported a lower psychosocial health summary score for themselves at follow-up. For emotional functioning, baseline mean was 66.7 ± 24.8, and two patients (40%, n = 2) reported worse functioning at follow-up (Fig. 2). For social functioning, baseline mean was 54.2 ± 32.9, and four patients (60%, n = 3) reported worse functioning at follow-up. For school functioning, baseline mean was 45.8 ± 30.1, and four patients (60%, n = 3) reported worse functioning at follow-up. Finally, for the total score, baseline mean was 53.4 ± 17.6, and one patient (20%, n = 1) reported a lower total score at follow-up.
Parent responses
Seven parents had baseline responses (88%, n = 7), of which six had follow-up responses (86%, n = 6) (Table 3). For the physical health summary score, the mean at baseline was 47.1 ± 8.4. At follow-up, all parents (100%, n = 7) reported worse functioning in their child. For the psychosocial health summary score, the baseline mean was 43.7 ± 16.0 and only one parent (17%, n = 1) reported a lower follow-up psychosocial health summary score. For emotional functioning, baseline mean was 52.9 ± 30.4, and four parents (67%, n = 4) reported worse functioning at follow-up. For social functioning, baseline mean was 44.6 ± 13.7, and four parents (67%, n = 4) reported worse functioning at follow-up. For school functioning, baseline mean was 33.6 ± 9.4, and three patients (50%, n = 3) reported worse functioning at follow-up. Finally, for the total score, baseline mean was 44.9 ± 8.6, and four parents (67%, n = 4) reported lower total scores at follow-up. Average difference between patient and parent total scores was 13.4 ± 9.1. Additionally, concordance in longitudinal changes in patient and parent total scores was 58% (n = 5). Parents were more likely to describe physical decline at follow up compared to the patients themselves. Although the remaining emotional, social and school functioning dimensions were more concordant between parents and patients, the total PQLQ parent scores were still lower at follow up compared to patients.
Cognitive and neuropsychological assessment
In our cohort, all patients (100%, n = 9) were affected by neuropsychological symptoms that included: learning difficulties (100%, n = 9), attention-deficit hyperactivity disorder (56%, n = 5), anxiety (44%, n = 4), depression (44%, n = 4), autism (22%, n = 2) and global developmental delay (11%, n = 1).
DAS-II
Six patients in the cohort completed the DAS-II at baseline. Figure 3a shows the average score for our cohort in each of the domains (see the scores for each domain for each patient in Supplementary Table 4). The mean at baseline for each domain in our cohort was: GCA, 67.0 ± 14.7; verbal, 66.3 ± 19.0; nonverbal, 70.5 ± 18.3; spatial, 68.7 ± 18.3.
Fig. 3
(a) Scores for patients for the DAS-II. Population mean and standard deviation for the domains tested are 100 (dashed line) ± 15 (dotted line). Patient 6, 8, 9 did not complete the DAS-II. Most DD patients lie below at least 1 standard deviation on both cognitive tests. (b) Scores for patients for the VABS-3. Population means and standard deviations for the domains tested are 100 (dashed line) ± 15 (dotted line). All patients completed this test at baseline only. The maximum score of the test is 170. Most of the patients scored below at least 1 standard deviation on all domains. DAS-II = Differential Ability Scales Second Edition, VABS-3 = Vineland Adaptive Behavior Scales Third Edition, GCA = General Conceptual Ability, ABC = Adaptive Behavior Composite, DLS = daily living skills
VABS-3
All patients completed the VABS-3 at baseline. The mean at baseline for each domain in our cohort was: ABC, 68.9 ± 11.4; communication, 66.2 ± 18.5; daily living skills 74.0 ± 11.7; socialization, 69.4 ± 10.9 (Fig. 3b; see the scores for each domain for each patient in Supplementary Table 5).
Ophthalmological assessment
DD patients very commonly have visual disturbances. In our cohort, eight patients had one or more ophthalmological changes (89%, n = 8): nyctalopia (11%, n = 1), photophobia (11%, n = 1), blurry vision (33%, n = 3), myopia (78%, n = 7), prescribed corrective lenses (78%, n = 7), and photophobia (89%, n = 8). The BCVA was within the normal range for all patients (100%, n = 9). Of note, hyperreflective foci were identified at the level of the outer nuclear layer (ONL) and the border of the outer plexiform layer in six patients (67%, n = 6) in SD-OCT (example in Fig. 4). These patients also had paler fundus pseudocolor images with what appeared to be a loss of retinal pigmentation. Fundus autofluorescence imaging demonstrated increased macular autofluorescence.
Fig. 4
Spectral Domain Optical Coherence Tomography (SD-OCT) of the left eye of patient 5 showing hyper-reflective foci on the border of the outer nuclear layer (ONL) foci and outer plexiform layer (OPL) (red circle and red arrows)
Cardiopulmonary assessment
Most patients in the cohort reported cardiac related symptoms (78%, n = 7): dyspnea (33%, n = 3), palpitations (44%, n = 4), and chest pain (56%, n = 5). All nine patients had baseline echocardiograms (100%, n = 9) and seven patients had follow-up echocardiograms (78%, n = 7). Regarding outcomes, one patient underwent transplantation during the study period at age 14. There were no deaths or ventricular assist device implantations. Two pediatric patients had baseline data only; one patient underwent cardiac transplantation and another patient stopped following up due to the COVID pandemic. Due to standardized z-score reporting in pediatric patients, we separated the pediatric patients (n = 8) from the adult patient (n = 1). The mean follow-up time was 24.5 months for the pediatric patients. Mean EF at baseline was 68.9 ± 4.8%. After the mean follow-up time, all six pediatric patients with follow-ups had lower EF values (100%, n = 6). The mean EF at last follow-up was 64.3 ± 8.5%, with an average paired difference of -5.9% which based on the Wilcoxon signed-rank test, was not statistically significant. The adult patient had a baseline EF of 47% and at last follow-up 41%.
For wall thickness, we utilized a maximum wall thickness (MWT) that measured the largest of the septal or posterior wall. The average MWT at baseline for the pediatric patients was 13.6 ± 7.1 mm (z-score = 6.9 ± 6.2; 75% [n = 6] of pediatric patients had a z-score > 2 at baseline). At last follow-up, wall thickness increased in all six pediatric patients (100%, n = 6). The mean MWT at last follow-up was 15.6 ± 6.8 mm (z-score = 9.4 ± 7.6), with an average paired difference of 3.8 mm, which based on the Wilcoxon signed-rank test, was not statistically signfiicant. For the young adult, his MWT was 30.4 mm at baseline and 28.2 mm at last follow-up after six months.
Mean LVEDD at baseline for the pediatric patients was 37.8 ± 5.7 mm (z-score = -1.6 ± 1.8). At last follow-up, four patients had a smaller LVEDD (67%, n = 4). Both patients with increased LVEDD, dilated in isolation of ventricular wall thinning, but did experience a drop in LVEF. The mean at last follow-up for the pediatric patients was 36.5 ± 6.7 mm (z-score = -2.1 ± 1.5), with an average paired difference of -0.5 mm. For the young adult, who had LV wall thinning and a drop in his LVEF during follow up, his LVEDD was 43.1 mm at baseline and 46.2 mm at last follow-up after six months.
Mean LV mass at baseline for the pediatric patients was 192.7 ± 133.1 g (z-score = 7.5 ± 6.6). Of the pediatric patients in the cohort (n = 8), 75% (n = 6) had a z-score >2 at baseline. At follow-up (n = 6), six patients had increased LV mass (100%, n = 6). Mean LV mass at last follow-up was 200.7 ± 88.9 g (z-score = 10.9 ± 12.0), with an average paired difference of + 66.2 g, which based on the Wilcoxon signed-rank test, was not statistically significant. For the young adult, he had an LV mass of 835.1 g at baseline and 789.1 g at follow-up after six months. Mean GLS at baseline for the pediatric patients was − 14.1% ± 2.9% which is lower than the − 20% measured in children without any cardiomyopathy [20]. Four pediatric patients (50%, n = 4) had follow-up GLS values, of which two had a GLS that was less negative (50%, n = 2). Mean GLS at last follow-up was − 14.7% ± 5.1%, with an average paired difference of + 0.14%. For the adult patient, the GLS at baseline was − 5.8% and at last follow-up was − 3.0%. Of note, this patient’s LVEF was already less than 50% base baseline. All echocardiogram data can be seen in Table 4; Fig. 5, and Supplementary Fig. 1.
Table 4 Summary table for cardiac measurements at baseline and at last follow-up, with a mean follow-up time of 24.5 months
Fig. 5
Echocardiogram findings for the pediatric patients in the cohort at their baseline and last follow-up visits. (a) LVEF plotted against age in our cohort. There is a downward trend (blue line) as age increases. (b) MWT z-scores plotted against age in our cohort. DD hearts thicken over time, as in this cohort. (c) LVEDD z-scores plotted against age. There is a downward trend in this age range. (d) LV mass z-scores plotted against age in our cohort. Despite the hearts having more mass, the scores remain relatively stable over time. The mean follow-up time for echocardiogram assessment was 24.5 months. MWT = maximum wall thickness, LVEDD = left ventricular end-diastolic dimension
Electrocardiogram findings
DD causes dysfunctional macroautophagy that results in accumulation of intracellular vacuoles, a mismatch between supply and demand of energy within cells and eventual cell death. The cardiac hypertrophy and fibrosis that occur result in significant electrophysiologic abnormalities including high voltage with repolarization abnormalities, conduction disorders, accessory pathways, and atrial and ventricular arrhythmias. Therefore, electrocardiogram (ECG) findings at baseline were also assessed in all nine patients. Baseline ECG findings included: Wolff-Parkinson-White (WPW) (56%, n = 5), LV hypertrophy (44%, n = 4), biventricular hypertrophy (22%, n = 1), sinus bradycardia (11%, n = 1), and 1st degree atrioventricular (AV) block (11%, n = 1).
Pulmonary function testing
Most of our patients (89%, n = 8) had respiratory related problems: wheezing (44%, n = 4), dyspnea (33%, n = 3), cough (22%, n = 2), asthma allergies (11%, n = 1), and sleep apnea (11%, n = 1). In our cohort, seven patients underwent PFTs at baseline (78%, n = 7) and five patients completed a follow-up visit (71%, n = 5). At baseline, the average percent of predicted seated upright FVC was 74.6% ± 8.5% (2.3 ± 1.3 L) (Table 5). After a mean follow-up time of 5.8 months, one patient had a lower upright FVC (20%, n = 1), one had no change (20%, n = 1), and three had an increase (60%, n = 3). The mean percent of predicted upright FVC at last follow-up was 74.0% ± 9.6% (2.4 ± 1.6 L).
Table 5 Pulmonary function testing results for the cohort
Mean percent of predicted supine FVC at baseline was 60.7% ± 12.6% (1.8 ± 1.2 L). After the mean follow-up time, from the five patients who completed a follow-up visit, one patient had a lower FVC (20%, n = 1), one had no change (20%, n = 1), and the rest had an increase (60%, n = 3). Last follow-up percent of predicted supine FVC was 64.4% ± 14.0% (2.0 ± 1.3 L).
The mean percent of predicted FEV1 was 53.6% ± 16.6% (1.6 ± 1.0 L). At follow-up, two patients had a lower percent of predicted FEV1 (40%, n = 2). The mean percent of predicted FEV1 at follow-up was 61.6% ± 16.8% (1.8 ± 1.3 L).
For the FEV1/FVC ratio, the mean percent of predicted was 103.4% ± 1.6% (0.89 ± 0.09). At follow-up, one patient had a lower percent of predicted FEV1/FVC (20%, n = 1), one had no change (20%, n = 1), and three had an increased (60%, n = 3). The mean at follow-up was 108.2% ± 7.7% (0.92 ± 0.05 L).
CPET
In this study, CPET was performed at baseline and at one follow-up visit, with a mean follow-up time of 5.2 months. Five patients performed CPET in our cohort (56%, n = 5) at baseline and at one follow-up, for a total of 10 visits. Our cohort had a baseline mean VO2 max of 17.2 ± 4.4 ml/kg/min (percent of predicted of 39.0 ± 9.0%) (Table 6; Fig. 6a, Supplementary Table 6). After a mean follow-up time of 5.2 months, three patients had a lower VO2 max (60%, n = 3). At last follow-up, the mean VO2 max was 17.6 ± 5.6 ml/kg/min (percent of predicted of 42.6 ± 13.0%). Out of the 10 total visits, six assessments reached an RQ of ≥ 1.0 (60%, n = 6). The baseline mean for ventilatory efficiency (VE/VCO2 slope) was 28.4 ± 2.5 (Table 6; Fig. 6b, Supplementary Table 6). After the mean follow-up time, two patients had a smaller VE/VCO2 slope (40%, n = 2). At last follow-up, the mean VE/VCO2 slope was 29.5 ± 3.2.
Table 6 Summary of CPET parameters and results of the 6MWT
Fig. 6
(a) VO2 max by age. There is a small positive correlation with age (blue line), likely due to lung maturity during puberty. (b) VE/VCO2 slope values plotted over time in the cohort. They remain stable over the 6 months. The mean follow-up time was 5.2 months
Neuromuscular assessment
Seven patients (78%) in our cohort reported neuromuscular symptoms at baseline: delay in motor milestones (67%, n = 6), difficulty running (67%, n = 6), difficulty walking (67%, n = 6), fatigue (67%, n = 6), weakness (67%, n = 6), joint pain (33%, n = 3), difficulty sitting (11%, n = 1), hypotonia (11%, n = 1), loss of range of motion (11%, n = 1), and abnormal gait (11%, n = 1). All limbs were found to be affected across the cohort: lower proximal limb (78%, n = 7), lower distal limb (67%, n = 6), upper proximal limb (56%, n = 5), upper distal limb (44%, n = 4).
For the 6MWT, all patients had baseline testing (100%, n = 9), but only seven patients had follow-up testing (78%, n = 7). At baseline, our cohort averaged 448.7 ± 64.7 m (Table 6; Fig. 7, Supplementary Table 7). After a mean follow-up time of 23.3 months, four patients walked shorter distances (57%, n = 4). The mean distance at last follow-up was 405.9 ± 136.1 m, with an average paired difference of -25.9 m.
Fig. 7
Longitudinal data for the 6-minute walk test (6MWT) at baseline and at follow-up for each patient in the cohort. The data is distance walked (meters) by age. Patients 6 and 7 only had baseline data. The mean follow-up time was 23.3 months
The results for the NSAA, 10MWT, time to rise from floor, and 4SC tests are shown in Fig. 8. For the NSAA, all patients completed the test at baseline (100%, n = 9). Seven patients completed follow-up visits (78%, n = 7), with a mean follow-up time of 23.1 months. The average NSAA total score at baseline was 28 ± 9 out of a max total of 34. After the follow-up time, one patient had a worse NSAA total score (14%, n = 1) and two patients had better scores (29%, n = 2) (Supplementary Table 8, Supplementary Fig. 4a). Out of the seven patients who had follow-up data, four (57%, n = 4) had no changes over 6-, 12-, 24-, and 36-month follow-ups. One of our patients, Patient 3, had markedly worse NSAA total score and 10MWT and 4SC times. Notably this patient had difficulty following instructions, which may have impacted these scores (Supplementary Fig. 4).
Fig. 8
(a) Baseline and last follow-up NSAA scores for the patients in the cohort. The maximum score is 34 (dashed line). The NSAA trended up with age (blue line). (b) Baseline and last follow-up speed during the 10MWT for our cohort. There is a positive correlation with age. (c) Baseline and last follow-up speed during the 4SC in our cohort. There is a positive correlation with age. The mean follow-up time for all these tests is 23.1 months. NSAA = North Star Ambulatory Assessment, 10MWT = 10-meter walk test, 4SC = 4-stair climb test
For the 10MWT, all nine patients (100%, n = 9) completed the test at baseline, but only seven (78%, n = 7) patients had follow-up testing done. The mean follow-up time was 19.4 months. In our cohort, ages 6–20, the baseline average speed was at 2.4 ± 0.6 m/s. At the end of study, two patients were slower (29%, n = 2). The average speed at follow-up was 2.2 ± 1.0 m/s.
For the time to rise from floor test, nine patients completed the test at baseline (100%, n = 9) and seven patients completed follow-up testing (78%, n = 7). The mean follow-up time was 23.3 months. The average time taken at baseline was 5.9 ± 4.1 s. At the end of the study, three patients took longer to rise from the floor (43%, n = 3). The mean time at last follow-up was 8.9 ± 11.8 s.
For the 4SC, we had nine patients complete the test at baseline (100%, n = 9), and seven patients with follow-up visits (78%, n = 7). The average speed at baseline was 1.1 ± 0.4 stairs/sec. After the mean follow-up time of 19.4 months, two patients were slower (29%, n = 2) (Fig. 8d).
Laboratory parameters
All patients completed the baseline laboratory measurements and follow-up with a mean follow-up time of 18.6 months. Of note, cardiac biomarkers including N-terminal pro brain natriuretic peptide (NT-proBNP) and high sensitivity cardiac troponin T (hs-cTnT) were elevated at both baseline and follow-up. Similarly, skeletal biomarkers including CPK and aldolase were similarly elevated at baseline and follow-up, as were AST, ALT and LDH (Table 7). Figure 9 shows the values for NT-proBNP and hs-cTnT for all patients at baseline and follow-up only, where mean paired difference was 971.3 pg/mL and 37.3 respectively, which based on Wilcoxon signed-rank test was a significant increase in NT-proBNP, but not hs-cTnT; Supplementary Fig. 5 shows the values at all visits.
Table 7 Lab values for the cohort, summarized at baseline and at last follow-up
Fig. 9
(a) Baseline and last follow-up NT-proBNP values for each patient. (b) Baseline and last follow-up hs-cTnT values for each patient. The mean follow-up time for all these tests is 18.7 months. NT-proBNP = N-terminal pro brain natriuretic peptide, hs-cTnT = high sensitivity cardiac troponin T
Establishment of T2DM rats fracture model and rats treatments
The work has been reported in line with the ARRIVE guidelines 2.0.
After adapting to feeding for three days, the Sprague Dawley (SD) rats were weighed and classified by cage (3 rats/cage), and 60 male SD rats of 3 weeks old were randomly distributed into 2 groups. Many studies have shown the procedures of establishing high-fat fed (HFD) and streptozotocin (STZ)-induced diabetic rat model which are a model of T2DM. According to the procedures of induction of the T2DM rat model in the existing study, after 3 weeks of feeding HFD (containing 60% fat), rats in the T2DM group were injected with STZ (40 mg/kg in citrate buffer). The control group fed with a normal pelleted diet received an equal volume of citrate buffer [21, 22].
The blood glucose (BG) levels were evaluated consecutively, and blood samples were collected from the tail vein. According to the procedures, rats with randomly blood glucose (RBG) samples > 16.7 mmol/L more than three times were identified to have T2DM after 7 weeks. During diabetes induction, animals were given free access to their original diets (received the high-fat or control diet and water ad libitum) for 12 weeks.
To assess the T2DM model, we measured the metabolic index, including body weight, food intake, water consumption and volume of excreted urine at several time points, including before being fed the HFD and 12 weeks after STZ injection. In addition, RBG was observed at several special time points, which included before fed HFD, before STZ injection, one week after STZ injection, 6 weeks after STZ injection and 12 weeks after STZ injection. At the end of the observation, IPGTT and ITT were evaluated. In detail, to execute IPGTT, animals were fasted for 12 h and injected with 1.5 g/kg glucose. BG was measured at 0, 30, 60 and 120 min after glucose injection. While ITT was carried out by injecting the rats with 0.75 IU/kg insulin, and then BG was obtained at 0, 30, 60 and 120 min after insulin administration. Animals with an RBG below 10 mmol/L at any time points were regarded as nondiabetic, and those with an RBG between 10 and 16.7 mmol/L were excluded. At 12 weeks after STZ injection, rats remaining in the T2DM group were evaluated as diabetic rats in a model of T2DM [23, 24].
After 15 weeks of treatment, all the successfully induced T2DM rats received general anesthesia with pentobarbital sodium intraperitoneal injection before surgery. A lateral incision was made along the proximal femur, followed by longitudinal dissection of the skin, subcutaneous tissue, and muscle along the femoral axis. The surrounding soft tissues were gently separated to expose the femur. A transverse osteotomy of the mid-diaphysis of the femur was performed by an oscillating mini-saw to establish a transverse femur shaft fracture model. The knee was bent 90 degrees, the lateral patellar incision was made, and the Kirschner needle was inserted femur intramedullary through the femoral intercondylar groove. The tip of the Kirschner needle was inserted through the top of the femoral greater trochanter to stabilize the fracture. Finally, all the incisions were closed using a 4-0 nylon suture. All the rats were kept in individual cages. Unprotected weight bearing was allowed immediately after the operation. After surgery, all the animals were given food and water ad libitum. At the end of the experiments, a sodium pentobarbital solution was administered intraperitoneally at a dose of 200 mg/kg. Following administration, animals were carefully monitored until the complete cessation of respiration and heartbeat, and a secondary physical method was applied when necessary to confirm death. All procedures were performed by personnel trained in rodent euthanasia.
Based on X-ray examinations, the fracture sites in the rats were located and marked on their skin. Then, 600 µL of ADSC-exosomes induced by mechanical stretch at a concentration of 200 µg/mL, as well as an equal volume of PBS, were locally injected into the fracture site every three days after surgery, with 200 µL administered each time. Finally, X-ray examination, micro-CT examination, histochemistry analysis, and Western blot analysis of the fractured femurs were performed 28 days after the operation.
Cells obtaining and culture
To obtain ADSCs, the subcutaneous fat in the groin of 3 weeks old male rats was cut into pieces as small as possible and centrifuged at 1500 rpm for 10 min to extract the sediment and glue enzyme was added in to digest at 37 °C for 40 min, then added the medium to terminate the reaction, and the mixture was filtered with a 70 μm filter. After centrifugating at 1500 rpm for 8 min, the cells were suspended in the medium and cultured in vitro for about 8 days. ADSCs (CD44+ CD90+ CD34-CD45-) were collected and certified by flow cytometry and the activity of ADSCs was determined by Calcein Acetoxymethyl Ester (Calcein AM) (Beyotime Biotechnology, Shanghai, China) staining assay.
Bone marrow cells were extracted from the femur and tibia of 3-week-old male rats, then isolated and cultured for 3 generations. BMSCs (CD44+ , CD34-) were identified by flow cytometry, and the cellular bioactivity of BMSCs was determined by Calcein AM staining assay.
The HUVECs (PUMC-HUVEC-T1; Cat NO: CL-0675) used in our experiments were originally purchased from a commercial vendor (Wuhan Pricella Biotechnology Co., Ltd.). To mimic the true condition and environment of Type 2 Diabetes Mellitus. All cells used in cellular function experiments were cultured with a complete culture medium consisting of high-concentration glucose (30 mM).
Tensile strain treatments of cells
Cell’s mechanical stimulation device has become a well-established method to apply mechanical strain to cultured cells; numerous similar devices for cell stimulation have been developed. In this study, external tensile strain was applied to ADSCs using a cell tension culture system. The special elastic membrane or well of the cell tension culture system was precoated with Matrigel (Corning, Bedford, MA, USA), incubated overnight, and kept moist with PBS for later use. ADSCs were cultured on the coated membrane or well. Cyclic tensile strain was applied using a uniaxial elongation model either 24 h post-seeding or upon reaching 90–100% confluence to simulate mechanical stimulation. In the selected uniaxial elongation model, cyclic sinusoidal tensile strain at a fixed frequency was applied to the cells according to a predefined protocol. All the ADSCs were divided into 3 groups, in which ADSCs were given of 1.0 Hz 6% (lower magnitude mechanical stretch ADSCs, LMS), 1.0 Hz 18% (higher magnitude mechanical stretch ADSCs, HMS) tensile strain, 2 h per day separately, and a total of 3 days. In the non-stress group (non-mechanical stretch ADSCs, NMS), 0% tensile strain was applied to ADSCs for 3 days in succession [25,26,27].
Isolation and identification of ADSC exosomes
After exposure to the corresponding tensile strain, ADSCs were washed three times with PBS and then cultured in exosome-free, FBS-free basal medium for an additional 24 h. Exosomes were isolated using the technique of differential centrifugation. In detail, the supernatant was collected and centrifuged at 1000×g at 4 °C for 10 min, 2000×g at 4 °C for 10 min, then centrifuged at 10000×g at 4 °C for 30 min, and centrifuged at 140000×g at 4 °C for 90 min in turn using a Beckman Coulter ultracentrifuge (Beckman Coulter, USA). Discard supernatant PBS washing sample, 140000×g centrifuge for 90 min at 4 °C. The precipitated exosomes were collected and re-suspended in 0.5 mL PBS and conserved at − 80 °C [28]. Then the volume of exosomes was concentrated to 200 μL. The morphology of exosomes was observed by transmission electron microscope (TEM; HITACHI, HT7700, JAPAN) and the diameter distribution was analyzed by Nanoparticles Tracking Analysis (NTA; ZetaView, Particle Metrix, Meerbusch, Germany). Western blot analysis identified its specific biomarkers (CD9, CD63, TSG101).
Flow cytometry (FCM) assay
ADSCs were analyzed by flow cytometry. ADSCs were detected with specific biomarker antibodies CD44 (Affinity), CD90 (Abcam), CD34, and CD45 (Abcam). BMSCs were certified by specific biomarkers CD44 (Affinity) and CD34 (Abcam). Results were analyzed using Flowjo software (version 10.0; BD Biosciences).
Exosome uptake assay
Based mainly on the manufacturer’s standard procedure, PKH26 was used as a dye to label the exosomes in the exosome uptake assay. In short, exosomes were obtained with differential centrifugation (140,000×g, 20 min, 4 °C) dyed with PKH26 (mixed solution was incubated for 20 min at room temperature). While BMSCs were seeded onto a 35 mm confocal dish at the proper density and labeled with DAPI dye. Then, exosomes labeled with PKH26 were mixed and co-cultured with BMSCs labeled with DAPI for 12 h and finally observed via a confocal laser scanning microscopy (CLSM, Leica Microsystems, Germany).
ALP activity and mineralization assessment of osteogenic differentiation
Following three passages of culture, BMSCs were seeded into 6-well plates (2 × 105 cells per well) that had been pre-coated with a 0.1% gelatin solution. The plates were then incubated for 14 days using a specific osteogenic induction medium (Cyagen Biosciences). To evaluate the effect of ADSCs-Exos on osteogenic differentiation, 200 µL of ADSCs-Exos (LMS-Exos, NMS-Exos, HMS-Exos derived from ADSCs) with a concentration of 200 µg/mL and equal volumes of PBS were added into every well severally with the osteogenic induction medium, and the medium was refreshed every three days. To evaluate the level of osteogenic differentiation, the cells were stained with alizarin red staining (ARS) dye and alkaline phosphatase (ALP) staining, and were collected for Western Blotting analysis on day 14. In detail, BMSCs were osteogenic induced for 14 days with different treatments, then cells were washed two times via PBS, then fixed with 4% paraformaldehyde for 30 min at room temperature prepare for ALP and ARS staining. A BCIP/NBT ALP kit (Beyotime, China) was used for ALP staining. After the stained cells were washed using PBS three times, the BCIP/NBT substrate was utilized to stain osteogenic-induced BMSCs. The results were observed and imaged via optical microscopy and then calculated and evaluated by the Image J software processing system (NIH, USA), and GraphPad Prism 10.0 (GraphPad Software, CA, USA) was used for the data analysis.
Tube formation assay of ADSC-Exos
HUVECs were cultured in Matrigel (Corning, USA) precoated 24-well plates (1 × 105 cells per well). 200 µL of ADSCs-Exos (LMS-Exos, NMS-Exos, HMS-Exos derived from ADSCs) with a concentration of 200 µg/mL and equal volumes of PBS were added into every well with the medium, respectively. 6 h later, tube formation was observed with a fluorescence microscope. The Image J software processing system (NIH, USA) and GraphPad Prism 10.0 (GraphPad Software, CA, USA) were used for quantification and data analysis.
Scratch test and migration test
HUVECs were cultured in 6-well plates (2 × 105 cells per well). 200 µL of ADSCs-Exos (LMS-Exos, NMS-Exos, HMS-Exos derived from ADSCs) with a concentration of 200 µg/mL and equal volumes of PBS were added into every well with the medium without serum. 24 h later when cultured HUVEC cells reached 100% confluence, a straight scratch was made with a 200 µL pipette in every well. 0 h, scratched wounds were observed with a fluorescence microscope and recorded. 12 h later, Scratch wound healing results were observed with a fluorescence microscope and photos were taken. Before observation, all samples were stained with calcein AM dye (Beyotime Biotechnology, Shanghai, China). The Image J software processing system (NIH, USA) and GraphPad Prism 10.0 (GraphPad Software, CA, USA) were used for quantification and data analysis.
Transwell assay
HUVECs treated with 200 µL of ADSCs-Exos (LMS-Exos, NMS-Exos, HMS-Exos derived from ADSCs) with a concentration of 200 µg/mL and equal volumes of PBS were seeded into 24-well transwell of 8 µm pore diameter cell culture plate (Corning, USA). 12 h later, HUVECs were stained with crystal violet for 20 min, and then observed by an optical microscope. The Image J software processing system (NIH, USA) and GraphPad Prism 10.0 (GraphPad Software, CA, USA) were used for quantification and the data analysis.
Cell alive/dead assays
All cells, including ADSCs, HUVECs, and BMSCs, were stained before use via calcein AM and Propidium iodide (PI) dye (Beyotime Biotechnology, Shanghai, China) to evaluate cell vitality.
Western blot analysis
Western blotting was performed following previously described protocols. First, after the concentrations of protein were measured via BCA (Aspen), the protein was separated into equal amounts via SDS-PAGE (Beyotime, China), transferred into the PVDF membrane (Millipore, Burlington, MA, USA) and then incubated with 5% bovine serum albumin for 1 h at 25 °C. Next, the membranes were incubated overnight with primary antibodies specific for CD9 (Abcam), CD63 (Abcam), TSG101 (Abcam), Runx2 (Abcam), OCN (Santa), and GAPDH (Abcam). HRP-labeled secondary antibody (Abcam, USA) was added, and then, the membrane was visualized using a T5200 Multi Chemiluminescence Detection System (Tanon, China) as recommended of the manufacturer. The membranes were incubated with Immobilon ECL reagent (Thermo Fisher Scientific, Waltham, MA, USA), and the bands were quantified via Image J software (NIH, USA). GAPDH protein level was used as an internal control for MACF1. The Image J software processing system (NIH, USA) and GraphPad Prism 10.0 (GraphPad Software, CA, USA) were used for quantification of protein level and the data analysis. The significance level was set to a 95% confidence interval, and statistical significance was declared as * p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001 and nsp > 0.05.
Micro-CT analysis
The animals were euthanized 4 weeks postoperatively, the internal fixations were removed and their femurs were fixed in 4% paraformaldehyde for 24 h at 4 °C. Then, tissue specimens were scanned via a micro-CT system (SkyScan1276, Bruker, Belgium) at a resolution of 9.054604 μm with 85 kV and 200 µA. After scanning, 3D structures of femurs were performed (Reconstruction was accomplished by NRecon (version 1.7.4.2)), and the new bone volume/total volume (BV/TV) were calculated to assess bone regeneration in the fracture site to assess the morphology of the reconstructed femurs (3D and 2D analysis were performed using software CT Analyser (version 1.20.3.0)).
qRT‑PCR analysis
Total RNA was isolated from exosomes using TRIZOL Extraction Reagent (G3013, Servicebio). The cDNA was reverse transcribed using RevertAid First Strand cDNA Synthesis Kit (Invitrogen, CA, USA) following the manufacturer’s instructions. And the qRT-PCR for mRNAs was performed on a StepOne™ Real-Time PCR System (Life technologies) using EnTurboSYBR Green PCR SuperMix (EQ001, ELK Biotechnology) or HieffTM qPCR SYBR™ Green Master Mix (No Rox Plus) (11201ES, Shanghai Yeasen BioTechnologies). The relative expression levels of mRNA or miRNA were normalized to those of GAPDH or U6 and evaluated using the 2−ΔΔCT method. The primers used for qRT-PCR are listed in Table 1.
Table 1 The sequences of primers used for PCR studies
Transfection
Following manufacturer’s protocols, miR-877 mimics or inhibitors and their NCs (Generalbiol, HeFei, China) were transfected into BMSCs and HUVECs to evaluate miR-877 function. After 48 h of transfection, the expression level of miR-877 was measured by qRT-PCR.
RNA sequencing and bioinformatics analysis
All the samples were processed as description previously. All the experiment procedures were according manufacture’s protocols and recommendations. Briefly, Total RNA was extracted from exosomes using TRIzol reagent (Invitrogen, CA, USA) according to the manufacturer’s protocol. Purity, concentration and integrity of RNA sample were examined by NanoDrop, Qubit 2.0, Agilent 2100, etc. RNA concentration and purity was measured using NanoDrop 2000 (Thermo Fisher Scientific, Wilmington, DE). RNA integrity was assessed using the RNA Nano 6000 Assay Kit of the Agilent Bioanalyzer 2100 system (Agilent Technologies, CA, USA). Only RNA with good quality could move on to following procedures. Total RNA from each sample was used to prepare miRNA library using NEB Next Ultra small RNA Sample Library Prep Kit (NEB, Boston, MA, USA) according to the Illumina small RNA sample preparation protocol. Sequencing was then performed on the Illumina novaseq6000 platform (Illumina, San Diego, CA). A total amount of 1.5 μg RNA per sample was used as input material for the RNA sample preparations. Briefly, first of all, ligated the 3′SR Adaptor. Mixed 3′SR Adaptor for Illumina, RNA and Nuclease-Free Water, after mixture system incubation for 2 min at 70 °C in a preheated thermal cycler, the Tube was transfer to ice. Then, add 3′ Ligation Reaction Buffer (2X) and 3′Ligation Enzyme Mix ligate the 3′SR Adaptor. Incubated for 1 h at 25 °C in a thermal cycler. To prevent adaptor-dimer formation, the SR RT Primer hybridizes to the excess of 3′SR Adaptor (that remains free after the 3′ligation reaction) and transforms the single stranded DNA adaptor into a double-stranded DNA molecule. And dsDNAs are not substrates for ligation mediated. The second, ligated the 5′SR Adaptor. Then, reverse transcription synthetic first chain. Last, PCR amplification and Size Selection. PAGE gel was used for electrophoresis fragment screening purposes, rubber cutting recycling as the pieces to get small RNA libraries. At last, PCR products were purified (AMPure XP system) and library quality was assessed on the Agilent Bioanalyzer 2100 system. The clustering of the index-coded samples was performed on a cBot Cluster Generation System using TruSeq PE Cluster Kit v4-cBot-HS (Illumia) according to the manufacturer’s instructions. After cluster generation, the library preparations were sequenced on an Illumina Hiseq 2500 platform and paired-end reads were generated. Raw data (raw reads) of fastq format were firstly processed through in-house perl scripts. In this step, clean data (clean reads) were obtained by removing reads containing adapter, ploy-N and low-quality reads from raw data. And reads were trimmed and cleaned by removing the sequences smaller than 18 nt or longer than 30 nt. Differential expression analysis of two groups was performed using the DESeq R package (1.10.1). DESeq provide statistical routines for determining differential expression in digital miRNA expression data using a model based on the negative binomial distribution. The resulting P values were adjusted using the Benjamini and Hochberg’s approach for controlling the false discovery rate. miRNA with an adjusted p < 0.05 found by DESeq were assigned as differentially expressed. Target gene function was annotated based on the following databases:Nr (NCBI non-redundant protein sequences); Nt (NCBI non-redundant nucleotide sequences); Pfam (Protein family); KOG/COG (Clusters of Orthologous Groups of proteins); Swiss-Prot (A manually annotated and reviewed protein sequence database); KO (KEGG Ortholog database); GO (Gene Ontology).
Histological and immunofluorescence analysis
The collected femurs of rats from different groups were fixed in 4% paraformaldehyde solution for 48 h, decalcified with 20% EDTA at 25 °C for 28 days, embedded in paraffin, and sectioned along the longitudinal axis. Sections from the fracture region were stained with hematoxylin and eosin (H&E), safranin O-fast green, Masson, RUNX2, OCN for immunohistochemical analysis. Immunofluorescence staining with α-SMA, CD31, RUNX2, OCN for immunofluorescence analysis. The sections were imaged and observed by a microscope.
Statistical analysis
All the experiments were performed at least three replicates per group. Values were presented as mean ± SD, and were analyzed with GraphPad Prism 10.0 (Graph-Pad Software, CA, USA). Variances between groups were assessed by the two-sided Student’s t-test (for two-group comparisons) or the one-way analysis of variance (ANOVA) with Tukey’s test (for more than two-group comparisons). And statistical significance was declared as* p < 0.05; ** p < 0.01; *** p < 0.001; **** p < 0.0001; nsp > 0.05, not significant.
Company to Spotlight Comprehensive Hip & Knee Portfolios and Latest Advancements in Robotics, Including the mBôs™ System Following Recent Acquisition of Monogram Technologies
WARSAW, Ind., Oct. 21, 2025 /PRNewswire/ — Zimmer Biomet Holdings, Inc. (NYSE and SIX: ZBH), a global medical technology leader, today announced that it is highlighting bold innovations across its broad robotics and musculoskeletal portfolio at the 2025 annual meeting of the American Association of Hip and Knee Surgeons (AAHKS).
During the meeting, the company’s booth will prominently feature its broad knee and hip portfolio of customer-centric solutions and infection solutions, along with the latest robotic technologies and data solutions to meet a vast array of surgeon techniques and preferences. Zimmer Biomet will also showcase the surgeon-guided robotic technology recently acquired through the Monogram Technologies Inc. acquisition.
“Orthopedics is at a pivotal moment,” said Ivan Tornos, Chairman, President and Chief Executive Officer of Zimmer Biomet. “As the population ages and expectations rise, patients are demanding more: less disruption, faster recovery and care that fits their lives. Surgeons need solutions that match this urgency, and that’s why we’ve engineered next-generation hip and knee implants and curated an ecosystem of robotics, digital platforms and AI. This isn’t incremental innovation — it’s the most ambitious innovation cycle in our company’s history, positioning Zimmer Biomet to deliver the industry’s most comprehensive and adaptable suite of orthopedic robotics and navigation technologies designed to elevate surgical precision and transform patient outcomes.”
The highlights at the Zimmer Biomet booth (#1206) include:
Digital and Technology Solutions
mBôs™ TKA System: a CT-based, semi-autonomous, total knee arthroplasty (TKA) robotic technology that received U.S. Food and Drug Administration (FDA) 510(k) clearance. A surgeon-guided fully autonomous version of this technology is currently in clinical trials.
ROSA® Knee with OptimiZe™: the newest version of the ROSA® Knee System that customizes and looks to enhance the surgeon’s experience with personalized and intelligent surgical planning, new positioning, tracking and alignment features to improve accuracy1 and reduce user variability,2 pending U.S. FDA 510(k) clearance.
TMINI® Miniature Robotic System: a state-of-the-art miniature, handheld, wireless CT-based robotic system designed to enable accurate and precise implant placement.
ZBEdge® Analytics : a data platform that delivers intra-operative, mobility and outcome insights directly on a smartphone application, enabling surgeons to objectively assess performance and understand the potential impact of clinical decisions on patient recovery.
mymobility® Care Management Platform : a digital care management platform that delivers continuous data and patient-reported feedback to facilitate care, outcomes and satisfaction about patients’ surgical preparation and recovery.
Knee Reconstruction Technologies
Oxford® Cementless Partial Knee : the only FDA-approved mobile cementless partial knee implant in the U.S. that has been shown to be efficient3,4 in the operating room and has been proven to have excellent survivorship5,6 worldwide.
Persona® OsseoTi® Keel Tibia : a cementless tibia for TKA with a 3D printed porous tray that provides stable initial and biological fixation and intra-operative versatility.7
Persona® SoluTion™ PPS® Femur : a knee implant component designed to serve as an alternative metal for patients with certain metal sensitivities like nickel and cobalt-chrome (Co, Cr, Ni) and bone cement that features a porous coating for cementless fixation and leverages a proprietary surface treatment designed to enhance wear performance.8,9
Persona IQ® The Smart Knee® : a first-to-world smart knee implant that captures patient-specific gait and range of motion metrics directly from the knee during patient monitoring to provide post-operative recovery insights10,11 and trends, allowing care teams to monitor and personalize the TKA patient experience.10-12
Hip Reconstruction Technologies
Z1® Femoral Hip System : offers an expansive size range and three distinct neck options designed to address a variety of patient anatomies and reconstructive needs.
OrthoGrid Hip AI® : an AI-powered, fluoroscopy-based technology that provides direct anterior hip surgeons with intuitive and instantaneous intra-operative tools to assist surgeons in achieving the desired surgical outcomes for component positioning.13
HAMMR® Automated Hip Impaction System : designed to address surgeon strain, fatigue and repetitive motion associated with the traditional mallet.
For more information about Zimmer Biomet events at 2025 AAHKS, visit https://www.zimmerbiomet.com/en/aahks2025.html.
About Zimmer Biomet
Zimmer Biomet is a global medical technology leader with a comprehensive portfolio designed to maximize mobility and improve health. We seamlessly transform the patient experience through our innovative products and suite of integrated digital and robotic technologies that leverage data, data analytics and artificial intelligence.
With 90+ years of trusted leadership and proven expertise, Zimmer Biomet is positioned to deliver the highest quality solutions to patients and providers. Our legacy continues to come to life today through our progressive culture of evolution and innovation.
For more information about our product portfolio, our operations in 25+ countries and sales in 100+ countries or about joining our team, visit www.zimmerbiomet.com or follow on LinkedIn at www.linkedin.com/company/zimmerbiomet or X at www.x.com/zimmerbiomet.
Important Safety Information for Oxford Cementless Partial Knee:
The Oxford® Cementless Partial Knee System is indicated for use in unilateral knee procedures with osteoarthritis or avascular necrosis limited to the medial compartment of the knee. It is intended to be implanted without the application of bone cement for patients whose clinical condition would benefit from a shorter surgical time compared to the cemented implant. The Oxford Partial Knee is not indicated for use in the lateral compartment or for patients with ligament deficiency, or for use in simultaneous bilateral surgery or planned staged bilateral procedures. Potential risks include, but are not limited to, loosening, dislocation, fracture, wear and infection, any of which can require additional surgery. For a full list of product indications, contraindications and warnings, please see the associated product Instructions For Use (IFU).
This news release contains forward-looking statements within the meaning of the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Forward-looking statements include, but are not limited to, statements concerning Zimmer Biomet’s expectations, plans, prospects, and product and service offerings, including new product launches and potential clinical successes. Such statements are based upon the current beliefs and expectations of management and are subject to significant risks, uncertainties and changes in circumstances that could cause actual outcomes and results to differ materially. For a list and description of some of such risks and uncertainties, see Zimmer Biomet’s periodic reports filed with the U.S. Securities and Exchange Commission (SEC). These factors should not be construed as exhaustive and should be read in conjunction with the other cautionary statements that are included in Zimmer Biomet’s filings with the SEC. Forward-looking statements speak only as of the date they are made, and Zimmer Biomet disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise. Readers of this news release are cautioned not to rely on these forward-looking statements, since there can be no assurance that these forward-looking statements will prove to be accurate. This cautionary statement is applicable to all forward-looking statements contained in this news release.
Laboratory and animal studies are not necessarily indicative of clinical performance.
THINK Surgical and TMINI are trademarks of THINK Surgical, Inc.
Persona IQ: The objective kinematic data generated by the CSE with CHIRP System are not intended to support clinical decision-making and have not been shown to provide any clinical benefit
References:
1 Data on File. DVaR-DS250106-01 ROSA Knee System v1.5 Validation Report. 2 Data on File. FER-EMS230714-01 Formative Evaluation Report – July Lab 2023. 3 Pandit, H., et al. “Improved fixation in cementless unicompartmental knee replacement: five-year results of a randomized controlled trial.” JBJS 95.15 (2013): 1365-1372. 4 Stempin R, Kaczmarek W, Stempin K, Dutka J. Midterm Results of Cementless and Cemented Unicondylar Knee Arthroplasty with Mobile Meniscal Bearing: A Prospective Cohort Study. Open Orthop J. 2017 Oct 31;11:1173-1178. doi: 10.2174/1874325001711011173. PMID: 29290853; PMCID: PMC5721307. 5 NJR- UK . The National Joint Registry 22st Annual Report 2025 London, 2024 [Available from: https://reports.njrcentre.org.uk/Portals/0/PDFdownloads/NJR%2022nd%20Annual%20Report%202025_Knees.pdf. 6 AOANJRR. Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR). Hip, Knee & Shoulder Arthroplasty: 2023 Annual Report Adelaide, AOA2024 [updated 2024. Available from: https://aoanjrr.sahmri.com/documents/10180/1798900/AOANJRR+2024+Annual+Report.pdf/9d0bfe03-2282-8fc8-a424-b8d9abb82b1f?t=1727666185313. 7 Mueller J.K., et al. Persona OsseoTi Keel Tibia Provides Stable Initial Fixation 4027.2-GLBL-en. November 2022. 8 Improved Abrasion Resistance of Nitrogen-Hardened Titanium Alloy Surfaces. Current Topics in Orthopaedic Technology. Zimmer. Vol. 3, No. 6 (1991). 9 Zimmer ZRR_WA_2537_12. 10 Cushner FD, Yergler J, ElashoffB, Aubin PM, VertaP, Scuderi GR. Staying Ahead of the Curve: The Case for Recovery Curves in Total Knee Arthroplasty. The Journal of Arthroplasty. 2024;doi:10.1016/j.arth.2024.07.039 11 Cushner FD, Sculco PK, Long WJ. The Talking Knee Is a Reality: What Your Knee Can Tell You After Total Knee Arthroplasty. J OrthopaedicExperience and Innovation. 2022;2022 12 Cushner FD, Schiller P, Gross J, Mueller JK, Hunter W. A Total Knee Arthroplasty Prosthesis Capable of Remote Patient Monitoring. OrthopaedicProceedings. 2021/06/01 2021;103-B(SUPP_9):18-18 doi:10.1302/1358-992X.2021.9.018 13 Cardenas JM, Gordon D, Waddell BS, Kitziger KJ, Peters PC Jr, Gladnick BP. Does Artificial Intelligence Outperform Humans Using Fluoroscopic-Assisted Computer Navigation for Total Hip Arthroplasty? Arthroplasty Today. 2024 May 27;27:101410. doi: 10.1016/j.artd.2024.101410. PMID: 38840694; PMCID: PMC11150909.
This study was conducted as a longitudinal cohort study through a retrospective review of medical records at NHO Fukuoka National Hospital. We reviewed 288 patients aged ≥ 20 years who met the American Thoracic Society/Infectious Diseases Society of America (ATS/IDSA) diagnostic criteria for MAC lung disease between April 1, 1996, and December 31, 2021 [6]. Of these, we excluded 42 patients with no available data of chest computed tomography (CT) scans between June 1, 2017, and December 31, 2021, 4 patients whose CT image data were unable to be processed for the present analysis by the software, 2 patients without any follow-up medical records after the date of CT scanning, 1 patient with no information concerning smoking history, and 7 patients without body mass index (BMI) data. Hence, the remaining 232 subjects with MAC lung disease were enrolled in the present study (Fig. 1). When multiple CT scans were available during the 2017–2021 period, the earliest scan was used for analysis. The follow-up period was defined as the time from the CT scan to either July 2023 or a maximum of 5 years.
Fig. 1
Quantitative CT image analysis
CT examinations were performed with a 160-slice multidetector CT scanner (Aquilion Lightning, Canon Medical Systems, Otawara, Japan) with a slice thickness of 5 mm. Quantitative CT image analyses were performed using dedicated software (AZE Virtual Place, Canon Medical Systems, Otawara, Japan) by a radiologic technologist without prior knowledge of the clinical data. For each patient, the lung field areas (LFAs) were evaluated separately in six domains using three axial CT slices in accordance with the Goddard score assessment protocols—the levels of the upper margin of the aortic arch (right and left upper lung field), the carina (right and left middle lung field), and 1–3 cm above the top of the diaphragm (right and left lower lung field) [13]. To identify the extent of cavitary destruction of the lung, the low-attenuation areas (LAAs) were defined as lung areas below − 950 Hounsfield units (HU), as in previous literature [14], and were also semiautomatically estimated using the same images (see Fig. S1 in Additional file 1) [15]. Mean values of LFA and LAA were calculated and used for the present analyses. The LFA/LAA ratio was computed for each of the six lung fields, and the average of these six values was used in the analysis. When dividing the study subjects into three groups based on the tertile distribution of the mean LFA, the cutoff values were as follows: lowest, ≤ 69.54 cm2 (N = 78); middle, 69.55–85.59 cm2 (N = 77); and highest, ≥ 85.60 cm2 (N = 77). For validation analysis between the mean values of LFA and lung volume (LV), a total of 9 subjects were randomly selected in order to assess LV. LV was calculated with the following 3 steps: at first, the lung plus bronchus volume (LBV) was identified by extracting the area less than − 500 HU. Next, the bronchus volume (BV) was measured by extracting the area less than − 920 HU and by ensuring the continuity of connection to other bronchi. Lastly, the LV was calculated by subtracting the BV from the LBV.
Clinical evaluations
For each case, respiratory physicians reviewed the patient’s medical records and assessed the demographic and clinical characteristics: age, gender, height, weight, smoking history, medical history, and results of mycobacterial cultures. BMI (kg/m2) was calculated as weight divided by squared height. Smoking habit was dichotomized as never smokers and smokers, considering that smoking could have affected emphysematous changes of the lung, appearing as low-attenuation areas (< −950 HU). Antibiotic treatment for MAC disease was defined as the prescription of clarithromycin and/or rifampicin and/or ethambutol. MAC species were categorized into three groups: M. avium group, Mycobacterium intracellulare (M. intracellulare) group, and co-infection group (subjects with both M. avium and M. intracellulare detected).
Statistical analysis
R software version 4.1.2 (R Foundation for Statistical Computing, Vienna, Austria) was used to perform all statistical analyses. A two-sided P < 0.05 was considered to indicate statistical significance. For baseline characteristics, the heterogeneity in each variable among the levels of mean LFA was evaluated using the analysis of variance (ANOVA), chi-square test, or Kruskal–Wallis test. Pearson’s correlation coefficient was calculated to assess the correlation between the mean values of LFA and those of LV. Kaplan–Meier curves were constructed to show the survival rate over the follow-up period. The unadjusted and multivariable-adjusted hazard ratios (HRs) with their 95% confidence intervals (95% CIs) according to the levels of mean LFA for all-cause mortality were estimated using a Cox proportional hazards model. Adjustments were made for age, gender, BMI, smoking history, MAC treatment, MAC species, co-infection with NTM other than MAC, and mean LAA, which has been reported as a potential prognostic factor in patients with NTM lung disease [16, 17]. Relevant models were used to evaluate the linear trends in the risk of all-cause death across the tertile classification of mean LFA. We evaluated the ability of mean LFA and mean LAA to predict mortality using receiver operating characteristic curves and estimated the area under the curve (AUC) for each. The AUCs were compared using the DeLong method. The robustness of the main results was tested through sensitivity analyses limiting the subjects to M. avium-positive or M. intracellulare-positive cases individually. Since smoking exposure can accelerate emphysematous change and increase the value of LAA in the lung, stratified analysis was performed by smoking status.
Ethical considerations
The study was approved by the NHO Fukuoka National Hospital Institutional Review Board for Clinical Research (#F5-34). For this study, informed consent has been waived by the NHO Fukuoka National Hospital Institutional Review Board due to the anonymity and retrospective nature of the study. This study was conducted according to the principles of the Declaration of Helsinki.
