Reconditioned pacemakers provide new hope for patients in low- and middle-income countries

European Society of Cardiology

Facebook

XLinkedInWeChatBlueskyMessageWhatsAppEmail

Madrid, Spain – 1 September 2025: Procedure-related infection rates were similar with reconditioned and new pacemakers, according to late-breaking research presented in a Hot Line session today at ESC Congress 2025.1 

Explaining the rationale for Project My Heart Your Heart, Doctor Thomas Crawford from the University of Michigan, Ann Arbor, USA, said: “Patients in many low- and middle-income countries (LMICs) still have very limited access to cardiac pacing despite its routine use in higher-income countries. Indeed, access to pacemaker implantation is around 200-fold lower in Africa than in Europe.2 To facilitate the use of reconditioned devices, Project My Heart Your Heart has developed a comprehensive protocol for cleaning, functional testing and sterilisation, and has gained FDA approval for their export to countries whose governments have provided express permission for pacemaker importation.3 We initiated a clinical trial to investigate the safety of implanting pacemakers reconditioned using our protocol compared with new devices in several LMICs.” 

A randomised controlled trial was conducted in Kenya, Mexico, Mozambique, Nigeria, Paraguay, Sierra Leone and Venezuela from May 2022 to June 2024. Adult patients with life expectancy of at least two years, a class I indication for pacemaker therapy and no financial means to acquire a new device were randomised 1:1 to receive a reconditioned pacemaker or a new pacemaker. The primary endpoint was procedure-related infection at 12 months. 

The trial included 306 patients who had a mean age of around 71 years. Approximately half were female. Follow-up data at 12 months were available for 259 patients (84.9%). 

Over 12 months, there were two pocket infections requiring explantation in the reconditioned pacemaker group and three in the new pacemaker group. There was one case of superficial cellulitis responsive to antibiotics in the new pacemaker group. Overall, the incidence of procedure-related infections at 12 months was 1.6% in patients in the reconditioned pacemaker group and 3.1% in the new group. The upper bound of the 90% confidence interval for the difference in infection rates between the groups was 2.2%, which is within the pre-specified noninferiority margin of 5%. 

There were no device malfunctions in either group. Lead revisions occurred in nine patients in the reconditioned pacemaker group and five in the new group. Unrelated to the implantation procedure, there were four deaths in the reconditioned pacemaker group and two in the new group.  

Concluding, Doctor Crawford said: “Our trial demonstrates the safety of pacemakers reconditioned using a specific protocol, with noninferior infection rates to new pacemakers and no malfunctions. The work of Project My Heart Your Heart serves as a blueprint that can be replicated by other organisations to enable wider pacemaker reuse. We would also like to expand into reconditioned implantable cardioverter-defibrillator devices, which are even more expensive and out of reach for many patients across the world.”  

 

Notes to editor 

This press release accompanies a presentation at ESC Congress 2025.  

It does not necessarily reflect the opinion of the European Society of Cardiology. 

Funding: The project is funded by private philanthropic donations.  

Disclosures: Doctor Crawford has no disclosures to report related to this trial. 

References and notes: 

1‘Project MHYH: One-Year Results’ presented during HOT LINE 9 on 1 September 2025 at 08:59 to 09:11 in Madrid (Main Auditorium). 

2Bonny A, Ngantcha M, Jeilan M, et al. Statistics on the use of cardiac electronic devices and interventional electrophysiological procedures in Africa from 2011 to 2016: report of the Pan African Society of Cardiology (PASCAR) Cardiac Arrhythmias and Pacing Task Forces. Europace. 2018;20:1513–1526. 

3Crawford TC, Allmendinger C, Snell J, et al. Cleaning and sterilization of used cardiac implantable electronic devices with process validation: the next hurdle in device recycling. JACC Clin Electrophysiol. 2017;3:623–631.

 

ESC Press Office  
Tel: +33 661401884    
Email: press@escardio.org   

The hashtag for ESC Congress 2025 is #ESCCongress  

Follow us on LinkedIn @European Society of Cardiology News 

Journalists are invited to become accredited and register here. 

Check out the ESC Media and Embargo Policy. 

About ESC Congress 2025 

It is the world’s largest gathering of cardiovascular professionals, disseminating ground-breaking science both onsite in Madrid and online – from 29 August to 1 September 2025. Explore the scientific programme. More information is available from the ESC Press Office at press@escardio.org. 

About the European Society of Cardiology 

The ESC brings together healthcare professionals from more than 150 countries, working to advance cardiovascular medicine and help people to live longer, healthier lives. 

 

Mirror image molecules reveal drought stress in the Amazon rainforest

New study by the Max Planck Institute for Chemistry shows: The ratio of certain forest scent molecules provides precise insights into the stress state of the rainforest

Max Planck Institute for Chemistry

Facebook

XLinkedInWeChatBlueskyMessageWhatsAppEmail

In 2023, the Amazon rainforest experienced its worst recorded drought since records began. River levels dropped dramatically and vegetation at all levels deteriorated due to intense heat and water shortages. In such conditions, plants release increased amounts of monoterpenes—small, volatile organic compounds that act as a defense mechanism and help communication with their environment. Some molecules, such as α-pinene, which smells like pine, occur as mirror-image pairs, known as enantiomers. 

The ratio of these two forms changes measurably when plants are under stress, for example due to heat or water shortage. Researchers at the Max Planck Institute for Chemistry investigated how this ratio changed in the Amazon before, during, and after the drought period. The results show that under normal conditions a clear ratio was consistently measured, but with increasing drought stress it shifted to ever higher values. In the most extreme phase of the drought, the usual ratio of the two α-pinene variants even reversed. Thus, the mirror molecules of α-pinene can tell us how much stress an ecosystem is currently under. 

Giovanni Pugliese, a scientist from the Max Planck Institute for Chemistry who was on site during the measurement campaign, recalls: “The heat was unbearable when collecting the samples. The forest was clearly suffering; its leaves were yellowing and the dry clay soil was cracking”. The problem in 2023 was that the September to October dry season coincided with an El Niño event. This is part of the global climate oscillation ENSO, and in El Niño mode, it brings extremely low rainfall and high temperatures to the Amazon basin.

Measurements deep in the rainforest

At the measuring station of the Amazon Tall Tower Observatory (ATTO), 150 kilometers northeast of Manaus, the researchers collected air samples at a height of 24 meters directly in the forest canopy. In the laboratory in Mainz, they later determined the ratio of the two α-pinene forms using chiral gas chromatography-time-of-flight-mass spectrometry. 

“First, we determined the ratio in which the two variants occur under normal conditions,” explains Joseph Byron, researcher at the Max Planck Institute for Chemistry and first author of the study. “We then observed how this ratio shifted during the El Niño-impacted dry season and slowly returned to normal afterwards.” 

Plants in survival mode

Project leader Jonathan Williams is impressed by these vegetation responses and explains further, “It is amazing that we can read directly from the air how the rainforest is reacting to current conditions. During the worst part of the drought, when the ratio flipped at midday, we knew that the vegetation had had enough, it had stopped photosynthesizing and closed up its pores to stop losing precious ground water ”.  This work builds on an earlier experimental drought study conducted in an enclosed forest grown within a greenhouse. (See https://www.mpic.de/5265797/spiegelmolekuele-trockenstress). There the Max Planck Research team  then showed that the two mirror-image molecules are released via different processes in the plant: while one form of α-pinene is released immediately after photosynthesis , the mirror molecule comes from storage pools within the plant.  The indoor experiment revealed this relationship and now this behavior has been recorded in the real-world extreme drought situation in the Amazon rainforest.

Significance for climate models

The Amazon rainforest is the world's largest source of biogenic volatile compounds. Using the ratio of α-pinene molecules, these emissions and their changes under drought conditions can now be represented more realistically in climate models. This is crucial because researchers expect more frequent and severe El Niño-related droughts in future.

Background ATTO

ATTO is a German-Brazilian joint project which was launched in 2009. It is managed by the Max Planck Institutes for Biogeochemistry in Jena and for Chemistry in Mainz, as well as by the Brazilian INPA and the Amazon State University (UEA) in Manaus. The project is funded by the German Federal Ministry of Education and Research (BMBF), the Ministério da Ciência, Tecnologia e Inovações (MCTI), the Max Planck Society and the Brazilian organizations including FAPEAM and individual researchers bring funding from other scientific funding agencies. 

The tower aims to deliver groundbreaking findings which will be the basis for improved climate models. With a height of 325 meters, the tower extends the ground-level boundary layer, and provides information from approximately 100 square kilometers of the world´s largest forest area. 

More on ATTO: https://www.mpic.de/3538403/ATTO

---

Journal

Communications Earth & Environment

DOI

10.1038/s43247-025-02709-z 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Mirror image molecules expose state of rainforest stress

 

Addition of progesterone leads to increased breast growth for those taking gender-affirming hormones

Amsterdam University Medical Center

Facebook

XLinkedInWeChatBlueskyMessageWhatsAppEmail

The addition of the hormone progesterone to gender-affirming hormone therapy leads to increased breast growth for transgender people following feminising hormone therapy. This is demonstrated by an Amsterdam UMC-led trial among 90 participants and these results are presented today at the European Professional Association for Transgender Health (EPATH) annual congress in Hamburg.

"Our results show that progesterone is safe and effective for transgender people. We're now able to prescribe it, in a trial setting, for those who have been taking oestradiol for at least year. We hope that our findings lead to better hormone treatments for transgender individuals,” says Koen Dreijerink, endocrinologist at Amsterdam UMC.

Gender-affirming hormone therapy helps an individual's body better align with their gender identity. In the case of feminising hormone therapy this involves blocking the action of testosterone and the addition of oestradiol. Traditionally, any breast growth is then limited, leading many transgender people to ultimately opt for breast augmentation surgery.

Breast Growth

Alongside oestradiol, progesterone is one of the two key female sex hormones. Progesterone is known in cis women to also cause breast growth. However, progesterone has not been prescribed in transgender people due to a lack of evidence of its effectiveness and safety. In order to gain more information of the effect on breast volume as well as the safety of progesterone, Dreijerink and his colleagues conducted a randomly controlled trail between 2021 and 2024.

"Among our 90 participants we repeatedly used 3D-scanning techniques to measure breast volume and saw up to an increase of 37%. Crucially, we also saw that the study participants were more satisfied with the size, shape and the growth of their breasts,” adds Raya Geels, PhD candidate at Amsterdam UMC and the study’s first author.

The largest increase was seen in the group who also increased their oestradiol dosage with some frequent side effects such as short-lasting tiredness, breast and nipple sensitivity and mood swings.

Participants in the study used progesterone for a year. “The reason we're moving forward with prescribing this in a research setting is to learn about the long-term effects and side-effects, for example we know that progesterone causes drowsiness so we advised our participants to take it prior to sleeping” adds Dreijerink. “It's important that we keep learning about the effects of gender affirming hormone therapy”.

 

$19.4M for an 'AI oracle' to solve complex physics problems

U-M leads new DOE-funded computational center focused on next-generation hypersonic flight

University of Michigan

Facebook

XLinkedInWeChatBlueskyMessageWhatsAppEmail

Simulation images

How much faster could engineering progress with an artificial intelligence oracle that could answer any physics question? 

 

Such a machine is the big picture aim of the newly formed Center for Prediction, Reasoning and Intelligence for Multiphysics Exploration, or C-PRIME, led by the University of Michigan and funded by the U.S. Department of Energy's National Nuclear Security Administration.

 

While physics is governed by many known equations, it’s hard to get from those equations to answers about how real-world objects will behave—for instance, the swirls of fuel and air inside a complex engine or the precise wind resistance over the surface of a vehicle. In theory, it’s all knowable, building up from the molecular level, but the calculations are too big to actually perform.

 

While an AI approach can't attack that problem directly, an AI agent could build physics models based on known equations that it uses to generate trustworthy data. It could then use that data to produce simplified yet accurate models for specific physics problems, which would feed into engineering design of complex devices. 

 

"The notion is that we, as humans, should provide certain concepts we trust—Newton's laws or E=mc^2. The machine then composes more complex ideas from these basic building blocks," said Venkat Raman, director of C-PRIME and the James Arthur Nicholls Collegiate Professor of Engineering.

 

"Because we trust these building blocks, we can—to a large extent—trust engineering concepts that are composed from them." 

 

However, formally establishing this trust, known as verification and validation, is in itself a complex challenge, which is at the core of the project. The sequences of simulations designed by the AI agents will run on some of the world's largest supercomputers to discover the inner workings of propulsion systems behind hypersonic flight—five times faster than the speed of sound. The team will focus on rotating detonation combustors, which are becoming a critical technology for hypersonic flight. 

 

Rotating detonation combustors can be used for propulsion—in rockets, air-breathing engines or satellite thrusters—or energy conversion, such as in gas turbines that generate electricity. They have the potential to be very efficient, roughly 25% better than conventional combustion, but maintaining their burn is a nuanced endeavor. A series of explosions run around a ring, and the resulting shockwave compresses and ignites the fuel-air mixture at each fuel injection point in sequence. 

 

"AI and hypersonics are critical to national security and U.S. scientific leadership, and we're committed to developing technologies and talent to move both fields forward," said Karen A. Thole, the Robert J. Vlasic Dean of Engineering. "This federal investment enables our researchers to bring together expertise in physics, computer simulation, AI and machine learning to push the boundaries of what's possible and develop tomorrow's AI-savvy workforce in the process." 

 

Student researchers on the project will draw on the University of Michigan’s Ph.D. in Scientific Computing—the nation’s first, established in 1988—administered by the Michigan Institute for Computational Discovery and Engineering, or MICDE.

 

The project is divided into five research thrusts:

• Physics and data: This effort covers foundational physics, developing models and honing them with experiments that fill holes in the existing data, with a focus on how materials mix and react. Led by Eric Johnsen, center co-director, professor of mechanical engineering and director of the scientific computing Ph.D. program. 

• Verification, validation and uncertainty quantification: With the goal of ensuring the accuracy and reliability of the computer models, this thrust digs into how assumptions and simplifications in the physics models affect predictions. Led by Alex Gorodetsky, associate professor of aerospace engineering.

• Exascale supercomputing architecture: This effort optimizes the models to take full advantage of powerful supercomputers and lays groundwork for building next-generation supercomputers optimized for AI. Led by Reetuparna Das, professor of computer science and engineering.

• Machine learning: This team will develop machine-learning-based tools that will accelerate computation of complex physics, using data generated by autonomously acting AI agents. Led by Karthik Duraisamy, professor of aerospace engineering and director of MICDE.

• AI-based integration: Based on "physics composition"—the formal approach for integrating different physics equations—this team will build the AI agents responsible for coding and simulation. Raman leads this thrust.

In addition, specially designed laboratory experiments will test the accuracy of the AI-based combustor design, to be conducted at U-M by Mirko Gamba, professor of aerospace engineering, and Carolyn Kuranz, professor of nuclear engineering and radiological sciences.

 

"Through our research, and the education of the next generation of researchers, we have the opportunity to shape the field on a large scale," Johnsen said. "In particular, we need to ensure that our trainees—undergraduate and graduate students and postdoctoral researchers—understand how to leverage AI resources in their research because their success after they leave Michigan will depend on how well they do this."

 

David Etim, federal program manager in the National Nuclear Security Administration's Office of Advanced Simulation and Computing and Institutional Research & Development, spoke highly of the new center, which is part of the fourth phase of NNSA's Predictive Science Academic Alliance Program. 

 

"This center with its focus on AI-driven solutions for complex physics problems aligns perfectly with PSAAP's mission to advance high-fidelity predictive simulations," Etim said. "We eagerly anticipate the groundbreaking contributions C-PRIME will make in areas critical to national security, particularly in next-generation hypersonic flight and exascale computing, further strengthening the program's impact."

 

C-PRIME builds on U-M's prominent leadership in computational science and engineering, which is anchored by MICDE. U-M is also home to a $15 million Strategic Partnership and Accelerated Research Collaboration with Los Alamos National Lab, which is coordinated by MICDE and brings together Los Alamos staff scientists and U-M researchers. Additionally, the university is partnering with LANL on a $1.25 billion facility for high-performance computing and AI research in Michigan.

 

C-PRIME includes a total of 13 co-investigators from U-M across four departments, as well as a co-investigator from Princeton University. Researchers at Sandia, Los Alamos and Lawrence Livermore national laboratories will be collaborating with the center. 

 

Raman is also a professor of aerospace engineering and mechanical engineering. Thole is also a professor of mechanical engineering and aerospace engineering. Duraisamy is also a professor of mechanical engineering and nuclear engineering and radiological sciences. 

AI turns printer into a partner in tissue engineering

University Medical Center Utrecht

Facebook

XLinkedInWeChatBlueskyMessageWhatsAppEmail

 

image: 

Sammy Florczak and Riccardo Levato in the volumetric printing lab.

view more 

Credit: Ivar Pel/UMC Utrecht

Organ donors can save lives, for example those of patients with kidney failure. Unfortunately, there are too few donors, and the waiting lists are long. 3D bioprinting of (parts of) organs may offer a solution to this shortage in the future. But printing living tissues, bioprinting, is extremely complex and challenging.

The team of Riccardo Levato at UMC Utrecht and Utrecht University is now taking an important step toward printing implantable tissues. Using computer vision, a branch of artificial intelligence (AI), they’ve developed a 3D printer that doesn’t just print, it also sees and even co-designs. Their innovation was published today in Nature. With this innovation, they tackle one of the biggest challenges in 3D bioprinting: improving both the survival and functionality of cells in printed living tissue. But how exactly does that work?

We usually associate 3D printing with building structures layer by layer. But there are other forms, such as volumetric bioprinting. This technique creates a complete structure in a single step, using a light-sensitive gel that solidifies when exposed to cell-friendly laser light. The advantage? It is incredibly fast, taking just seconds, and much gentler on living cells. To produce a high-quality print, it is crucial to understand what’s inside the printing material, so that the printed object is built as optimal as possible. The new technology, called GRACE, makes that possible. It opens up new possibilities for bioprinting functional tissues, and brings us closer to repairing tissues, testing new drugs, and even replacing entire organs.

---

Why do we need GRACE?

What is 3D-bioprinting? 
In 3D bioprinting, researchers use living cells to create functional tissues and organs. Instead of printing with plastic, they print with living cells. This comes with great challenges. Cells are fragile and wouldn’t survive a regular 3D printing process. That’s why Riccardo Levato’s team developed a special bio-ink, a mix of living cells and nourishing gels that protect the cells during the printing process.

Volumetric bioprinting 
With the advancements in bio-inks, layer-by-layer 3D bioprinting became possible. But this method is still time-consuming and puts a lot of stress on the cells. Researchers from Utrecht came up with a solution: volumetric bioprinting.

Volumetric bioprinting is faster and gentler on cells. Using cell friendly laser light, a 3D structure is created all at once. “To build a structure, we project a series of light patterns into a spinning tube filled with light-sensitive gel and cells,” Riccardo Levato explains. “Where the light beams converge, the material solidifies. This creates a full 3D object in one go, without having to touch the cells.” To do this, it is crucial to know exactly where the cells are in the gel. GRACE now makes that possible.

---

Innovating with laser light

Sammy Florczak, a PhD student in Riccardo’s lab, worked on the development of GRACE, short for Generative, Adaptive, Context-Aware 3D printing. He built a new device in a specialized lab, using advanced laser technologies. Before entering, a red light signaling “LASER” shows whether it’s safe to go in. Laser light plays a crucial role, not just in the printing step, but also in the added imaging step that sets this new technology apart. GRACE combines volumetric bioprinting with this advanced laser-based light-sheet imaging. But what can we do with that?

Smart blood vessels around living cells

One of the biggest challenges in 3D bioprinting is creating functional blood vessels. Blood vessels are essential to provide oxygen and nutrients to the cells, and thus printing these blood vessels at the correct place is key to creating viable tissues. Yet, in conventional printing methods, a 3D design is made before knowing where the cells are located in the light sensitive gel and thus where the blood vessels must be printed. With GRACE, the printer ‘sees’ where the cells are located and, within seconds, designs a network of blood vessels around those cells as effectively as possible.

From blueprint to customization

“In the past, printing always depended on the designer’s blueprint. Now, GRACE contributes to the design itself,” Sammy explains. “The printer ‘sees’ what kind of cells are in the material, and where they are. Then, using AI tools, it creates a matching design for the object to be printed. This new printer essentially has its own ‘eyes’ – the laser-based imaging- and ‘brain’ – the new AI software. That level of customization leads to tissues that survive and function better.”

More than just blood vessels

GRACE can do more than create adaptive blood vessels networks. The technology can also align multiple printing steps automatically. Take a piece of printed bone tissue, for example, that later needs a layer of cartilage added. Normally, that is a complex process with a lot of manual work. GRACE scans the existing tissue and automatically designs and prints a second layer that fits perfectly on top. All at the high printing speed of volumetric bioprinting, creating cm3-sized objects within seconds.

Automatically correcting for obstacles

Another challenge in bioprinting is that light can sometimes be blocked, for example by previously printed parts of the structure. This can create shadows and flaws in the final product. GRACE can solve this too. By scanning the surface of any obstacles, the system automatically adjusts the light projection. This makes the print more precise and consistent. Moreover, this allows pre-made objects to be inserted into the printing vial. Think for example of a stent in which you could print blood vessel cells or objects that can release medicines.

Just the beginning

Bioprinting is highly promising, but significant work is still needed to translate this technology to the clinic. Riccardo underlines that further research is needed to determine how printed cells can mature to replicate the functionality of native tissues. Even considering the challenges ahead, Riccardo is not afraid to dream big. “This first work on GRACE is just the beginning. We are now working on increasing the amount of cells that can be printed, so that other tissues like heart and liver can also be printed. Moreover, we would like to make this technique openly accessible to other labs, so other could apply it to their printing method.”

https://www.youtube.com/watch?v=hA0zzosxMy4&t=5s

---

Journal

Nature

DOI

10.1038/s41586-025-09436-7 

Article Title

Adaptive and context-aware volumetric printing

Article Publication Date

3-Sep-2025