Percutaneous coronary intervention, commonly known as PCI, is the definitive emergency treatment for many heart attacks. The procedure involves threading a catheter, usually through an artery in the wrist or groin, up to the blocked coronary artery that is starving heart muscle of oxygen. Cardiologists then inflate a small balloon and typically deploy a stent, a tiny metal scaffold, to prop the vessel open and restore blood flow. The intervention is exquisitely time-sensitive: the longer the artery stays occluded, the more heart muscle dies, and the greater the risk of fatal arrhythmias, heart failure, and death. That time dependence is why emergency medicine guidelines emphasize rapid door-to-balloon intervals, and why the geographic distance between a patient and a PCI-capable hospital can be a matter of life and death. Establishing a PCI program is also expensive and demanding, requiring specialized catheterization suites, imaging equipment, and a round-the-clock team of interventional cardiologists, nurses, and technicians.

The research team, led by Yu-Chu Shen of the Naval Postgraduate School and the National Bureau of Economic Research and Renee Y. Hsia, professor of emergency medicine at UCSF, took advantage of a natural experiment embedded in California’s health care landscape. Between 2011 and 2022, various hospitals across the state opened new PCI-capable facilities at different times and in different places. The researchers identified 590,282 hospitalizations for acute myocardial infarction, the medical term for heart attack, and asked a deceptively simple question: what happened to patients in a community after a PCI-capable facility opened within a 30-minute drive? Crucially, they separated communities into two groups based on their starting point, comparing places that had never had timely PCI access with places that already had a capable hospital within the same 30-minute radius.

The contrast between the two groups was stark. In communities that previously lacked timely access, the opening of a new facility was associated with a 53 percent relative increase in the likelihood that a heart attack patient would be admitted to a hospital capable of performing PCI, and a 16 percent increase in the likelihood that the patient would actually receive the procedure. Those changes in treatment were accompanied by substantial changes in survival: thirty-day mortality among heart attack patients fell by 20 percent, and one-year mortality fell by 15 percent. In communities where PCI was already available within 30 minutes, by contrast, the opening of yet another facility increased admission to a PCI-capable hospital by only 2 percent and use of the procedure by only 3 percent, and the study detected no significant change in mortality at either time horizon.

The pattern reveals a fundamental asymmetry in how health care capacity behaves. Where a service is absent, adding it changes clinical behavior profoundly, rerouting patients who would otherwise have received less definitive therapy toward the lifesaving procedure. Where the service already exists, an additional facility mostly reshuffles existing patterns of care, drawing some patients from one capable hospital to another without meaningfully changing who gets treated or how quickly. In economic terms, the marginal benefit of the first facility within reach of a population is enormous, while the marginal benefit of the second or third approaches zero. Hsia illustrated the point with a deliberately mundane analogy: adding another gas station to a neighborhood that already has five may make refueling slightly more convenient, but building one where residents previously had to drive 30 miles meets a genuine need. With emergency cardiac care, she noted, filling that kind of gap can save lives.

The geographic dimension of the problem was most acute in rural California. Among the 52,756 heart attack patients in the study who came from rural communities, 81 percent lived in places without a PCI-capable facility within a 30-minute drive at the beginning of the study period. That figure captures a structural vulnerability of rural health systems: specialized services that require high volumes, expensive equipment, and scarce subspecialists tend to concentrate in urban and suburban population centers, leaving rural patients with long transport times precisely when minutes matter most. For these communities, the study’s findings suggest that even a single new PCI-capable facility could produce mortality reductions on the order of 15 to 20 percent, an effect size that few other health system interventions can match.

The new analysis builds directly on earlier work by Hsia and colleagues, which had examined the supply side of the same question. That previous study found that the total number of PCI procedures performed in a community rose by 7.5 percent after a new facility opened, but the increase was far from uniform: it approached 20 percent in communities that had previously lacked timely access, compared with roughly 8 percent in communities where PCI was already available. In other words, new capacity reliably generates more procedures, but the increase partly reflects redistribution of existing patients among competing hospitals rather than genuinely new treatment for people who would otherwise have gone without. The current study extends that logic to the outcome that ultimately matters, asking whether the additional procedures improved survival, and finding that the answer depends entirely on whether the capacity filled a gap or duplicated an existing service.

That distinction carries weight because of how decisions about specialized services are actually made in the American health system. The researchers point out that the placement of new facilities is frequently driven by market demand, expected procedure volumes, and hospitals’ anticipated return on investment rather than by systematic assessments of population need. A hospital system may find it financially attractive to open a second PCI laboratory in a well-served suburban corridor where it can capture market share from a competitor, while no institution finds it profitable to establish one in a rural county with a small and dispersed population. The result, the study implies, is a systematic misallocation: capital flows toward communities where the clinical benefit of additional capacity is smallest, while the places where a new facility would save the most lives remain unserved. Market forces, in this domain, do not naturally point resources toward maximal population health benefit.

For policymakers, the findings suggest a concrete principle for allocating scarce health care infrastructure investment: measure access before adding capacity. Rather than asking whether a region can support more specialized services, planners could ask whether residents can already reach those services within the critical treatment window, and direct new facilities and support programs toward the communities that cannot. Hsia framed the principle as a question of priorities. When millions of dollars are invested in specialized health care infrastructure, she argued, the question should not simply be whether more services can be provided, but where those services will do the most good. Expanding access, she said, needs to be done wisely. The study’s mortality figures give that advice quantitative teeth: the same investment that yields no measurable survival benefit in a saturated market can cut heart attack deaths by a fifth in a community that has been going without.

The research also carries a broader lesson for how the public and the press evaluate health care expansion announcements. A ribbon-cutting for a new specialty facility is often reported as an unambiguous improvement in local care, and in a community with no existing access, that framing is accurate. But the California data show that in well-served areas, additional capacity may increase treatment rates only marginally while leaving survival untouched, meaning the true value of such investments is far smaller than the rhetoric suggests. As health systems, insurers, and governments confront rising costs and finite resources, the study offers a reminder that in medicine, as in geography, position matters. The lifesaving power of a procedure like PCI is not just a property of the catheter and the stent; it is a property of the distance between the patient and the door.

Subject of Research: Geographic access to percutaneous coronary intervention facilities and heart attack survival outcomes

Article Title: When it comes to health care access, more isn't always better

Article References: When it comes to health care access, more isn't always better. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: heart attack, percutaneous coronary intervention, health care access, rural health, mortality, emergency care, health policy, hospital capacity, California, JAMA Network Open, cardiovascular disease, health care infrastructure

That lack of an internal mechanic has long frustrated cardiovascular scientists, because the machinery for repair is not entirely absent from mammalian biology. Neonatal mice, for example, can fully regenerate their hearts for roughly the first week after birth, seamlessly replacing lost muscle without scarring before that capacity vanishes as the animal matures. Humans and other mammals follow a similar trajectory, losing regenerative power early in development. The central question that has animated the field for years is whether that fix-it ability is destroyed outright or merely switched off and left dormant, waiting for the right signal to bring it back.

A new study suggests it is the latter, and it identifies a plausible way to flip the switch back on. Researchers at Sanford Burnham Prebys Medical Discovery Institute, working with collaborators across the United States, published findings on September 28, 2026 in Nature Cardiovascular Research showing that blocking a single metabolic enzyme in the heart triggers coordinated changes in gene regulation across multiple cardiac cell types, promoting cell proliferation, new blood vessel formation, reduced scarring and improved heart function in mice after heart attack. The target is succinate dehydrogenase, a key enzyme complex in the mitochondrial electron transport chain and the tricarboxylic acid cycle that sits at the heart of cellular energy production.

The team had previously shown that pharmacologically inhibiting succinate dehydrogenase with a metabolite called malonate rewires how adult heart cells generate energy, effectively resetting their metabolism to resemble that of neonatal heart muscle cells. In that earlier work, the metabolic reset prompted cardiomyocytes to re-enter the cell cycle and proliferate while supporting tissue regeneration. What remained unclear was exactly what was happening inside the cells, at the level of genes and their regulation, when metabolism was shifted in this way. Understanding that mechanism would be essential if the approach is ever to move from mouse studies toward clinical testing.

To dissect the mechanism, the investigators used sequencing techniques to measure changes in gene expression and DNA accessibility in mice treated with malonate. DNA accessibility refers to how loosely or tightly the genetic material is packaged inside the cell; when stretches of DNA are open, the cellular machinery that reads genes can reach them, and when they are closed, those genes stay silent. In cardiomyocytes, the analysis showed that regions of DNA associated with pro-regenerative genes and with the cell cycle became more accessible after treatment, making it easier for the cells to activate programs of proliferation and repair. Perhaps just as striking was what happened in a different population of cells entirely: in cardiac fibroblasts, the connective tissue cells of the heart, the treatment suppressed the gene programs that drive scar formation.

Those two observations raised an obvious question. Which of the two cell types was actually responsible for the regenerative benefit? A malonate injection circulates throughout the heart and vascular system, inhibiting succinate dehydrogenase everywhere at once, so the team needed a way to isolate the effect. Their answer came from two newly developed mouse models genetically altered so that succinate dehydrogenase activity was disrupted selectively, either in the heart’s muscle cells or in its connective tissue cells. Blocking the enzyme specifically in cardiomyocytes produced a transient increase in their proliferation, but that alone was not enough to improve heart function after a heart attack. Blocking it in cardiac fibroblasts, by contrast, suppressed their activation, reduced scar formation and resulted in improved cardiac function.

The result forced a revision of the team’s working assumptions. As co-first author Dakota Nuttall, a PhD student in the lab of senior author Ahmed Mahmoud, put it, the researchers were somewhat focused on cardiomyocytes in their initial hypotheses, but the results demonstrated the importance of both cell types for successful regeneration and recovery. Mahmoud, interim director and associate professor in the Center for Cardiovascular and Muscular Diseases at Sanford Burnham Prebys, described the process as a multicellular effect driving regeneration, something the team could not fully appreciate until the effects of metabolic reprogramming were isolated in the different cell types. In other words, regeneration is not a solo performance by heart muscle cells; it is an ensemble piece in which muscle and fibroblast populations respond together to a shared metabolic cue.

Timing, too, emerged as a critical variable in the new work. The genetic models disrupt succinate dehydrogenase activity continuously, whereas malonate inhibits the enzyme only temporarily. That difference matters, because a sustained metabolic shift could lock heart cells into a state incompatible with the mature metabolism they need for normal contractile function, while a transient pulse of inhibition could allow cells to enter a regenerative state and then return to their ordinary operating mode. The idea that a brief metabolic window might be sufficient to reawaken developmental repair programs, without permanently altering the heart’s energy economy, has significant implications for how such a therapy might one day be designed and dosed.

In a final round of experiments, the researchers returned to malonate treatment in mice to examine how the therapy changed the packaging and regulation of DNA itself. DNA is wound like thread around histones, the biological spools that organize the genome, and chemical tags added to or removed from those spools can tighten or loosen the coil, closing off nearby genes or opening them up for expression. In cardiomyocytes, the team observed activating histone modifications associated with genes important for regeneration being switched on. In cardiac fibroblasts, they saw changes in histone marks that turned down genes involved in scarring and fibrosis. The treatment, in other words, functions as a metabolic epigenetic switch, using energy metabolism as a lever to reconfigure the regulatory landscape of the injured heart across cell types simultaneously.

For Mahmoud, that breadth is what makes the strategy exciting. Rather than targeting a single regenerative pathway, he explained, the approach changes the metabolic state of the tissue in a way that coordinates responses across multiple cell types, reawakening several features of the regenerative response normally seen in the neonatal heart. The long-term goal is to translate the concept toward clinical testing and ultimately develop a therapy for the more than 800,000 people in the United States who experience a heart attack each year. There is still a long road from mouse models to human medicine, and Mahmoud disclosed competing interests that include co-founding a company, Mount Therapeutics, and co-inventing a US patent covering succinate dehydrogenase inhibition for cardiac regeneration. But the study provides a mechanistic foundation for a therapeutic idea that once seemed fantastical: that the mammalian heart’s lost capacity for self-repair is not gone, only silenced, and that the silencing can be reversed with the right metabolic signal at the right moment.

Subject of Research: Metabolic and epigenetic reprogramming of cardiac cells to promote heart regeneration after myocardial infarction

Article Title: Modifying heart cell metabolism unlocks self-repair system after heart attack

Article References: Modifying heart cell metabolism unlocks self-repair system after heart attack. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: cardiac regeneration, heart attack, succinate dehydrogenase, malonate, cardiomyocytes, cardiac fibroblasts, metabolic reprogramming, epigenetics, histone modifications, scar formation, neonatal heart, Sanford Burnham Prebys

The work was led by Professor Michio Nakaya of the Research Institute of Environmental Medicine at Nagoya University, in collaboration with colleagues from Kyushu University and Tokushima University. Their central discovery concerns the metabolic machinery that scar-forming cells rely on to manufacture collagen, the structural protein that makes up roughly a fifth of the raw material in the form of a single amino acid: proline. By disrupting the supply chain for this building block, the team found they could throttle collagen production at its source.

Fibrosis is not unique to the heart. The same runaway deposition of collagen-based scar tissue can afflict the liver, where chronic injury can progress to cirrhosis, and it is estimated to contribute to as many as 45 percent of deaths in developed countries. Despite this enormous disease burden, no definitive therapy exists that directly suppresses the fibrotic process itself. Current treatments generally manage symptoms or slow progression rather than halting the underlying cellular program that turns healthy tissue into stiff, nonfunctional scar.

To understand why the heart is so vulnerable, it helps to look at the cells responsible. After inflammation or injury, specialized cells called myofibroblasts flood into the damaged area and begin producing collagen on an industrial scale, reinforcing the wound much as rebar reinforces concrete. In the short term this is protective, preventing the weakened heart wall from rupturing under pressure. But when the response becomes chronic, the accumulating collagen stiffens the myocardium, impairs contraction, and sets the stage for heart failure, which frequently develops in patients in the months and years following a myocardial infarction.

Because approximately 20 percent of collagen consists of proline, the Nagoya-led team reasoned that the way myofibroblasts produce and supply this amino acid might be a critical vulnerability. They began by comparing genes activated by physical stress with those switched on in mouse hearts after a heart attack, searching for molecular players common to both settings. This screen identified five overlapping candidates, among them Bcat1, the gene encoding branched-chain amino acid transaminase 1. The researchers homed in on BCAT1 because its role in myofibroblasts had never been explored, leaving open the possibility that it represented an untapped therapeutic target.

What they found was striking. In healthy mouse hearts, BCAT1 was barely detectable. But after a heart attack, levels of the enzyme rose sharply in collagen-producing cells, climbing in step with the progression of fibrosis. Follow-up experiments revealed that BCAT1 activates a cellular pathway that maintains the supply of proline, effectively functioning as part of the material-delivery system that fibrotic cells use to sustain their enormous output of collagen. In other words, the enzyme does not merely accompany scarring; it helps feed it.

The causal role of BCAT1 became clear when the team studied mice genetically engineered to lack the enzyme. After suffering a heart attack, these animals produced fewer proline-related enzymes and less collagen than their normal counterparts. They developed less scar tissue and, crucially, maintained better heart function than control mice. The histological evidence was equally compelling: heart tissue sections stained with Picrosirius red, which highlights collagen in red, showed markedly reduced collagen deposition in BCAT1-deficient mice 28 days after a heart attack compared with normal mice subjected to the same injury.

Genetic deletion, however, is not a practical treatment for patients who arrive at the hospital after an attack has already happened. So the researchers turned to pharmacology, testing a BCAT1 inhibitor called ERG240 in mice following induced heart attacks. The results were notable for their timing flexibility: ERG240 administration reduced scarring and preserved heart function even when treatment began seven days after injury, during the transition from the acute inflammatory phase to the chronic fibrotic phase. This delayed-treatment window matters enormously in clinical terms, because real-world interventions almost always occur after a heart attack rather than before it. A therapy that only works prophylactically would be of limited use; one that can reverse course after fibrosis has begun is far more valuable.

The mouse findings also appear to translate to human disease. When the team analyzed human heart tissue from patients with heart failure, they found elevated BCAT1 levels linked to increased fibrosis, suggesting that a similar enzyme-driven mechanism operates in human hearts. Intriguingly, the researchers also detected higher BCAT1 levels in the livers of patients with fatty liver disease, hinting that the same proline-supply pathway may drive fibrosis in organs well beyond the heart. The team’s next step is to determine whether the BCAT1-proline pathway also promotes fibrosis in the liver and other tissues, and to develop clinically applicable BCAT1-targeted therapies while assessing their safety, optimal dosing, and efficacy.

Perhaps the most attractive feature of BCAT1 as a drug target is its selectivity. Because the enzyme is mostly absent from healthy tissue and becomes primarily active in scar-forming cells, blocking it should, in principle, suppress pathological collagen production without disturbing the normal collagen turnover that healthy organs depend on. That specificity could translate into fewer side effects than existing anti-fibrotic treatments, which often act on broader pathways and carry a heavier burden of toxicity. As Nakaya put it, “We found that BCAT1 is a new driver of excessive collagen production in the fibrotic heart by increasing the supply of proline, a major building block of collagen. Importantly, pharmacological inhibition of BCAT1 suppressed cardiac fibrosis and preserved cardiac function, even when treatment started after fibrosis had begun to develop.” If the pathway holds up in further studies across organs and eventually in human trials, a metabolic vulnerability shared by fibrotic diseases of the heart, liver, and beyond may finally have a common weak point.

Subject of Research: The role of the enzyme BCAT1 in proline-dependent collagen production and cardiac fibrosis after heart attack

Article Title: Blocking enzyme reduces heart failure risk after heart attack in mice

Article References: Blocking enzyme reduces heart failure risk after heart attack in mice. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: BCAT1, cardiac fibrosis, heart attack, heart failure, collagen, proline, myofibroblasts, ERG240, Nagoya University, Journal of Clinical Investigation, enzyme inhibitor, fatty liver disease

The stakes of this question are enormous. Ischemic heart disease remains the leading cause of death worldwide, and while timely reperfusion of a blocked coronary artery has dramatically reduced mortality, myocardial necrosis is often unavoidable. The surviving ventricle then embarks on a remodeling process—chamber dilation, wall thinning, scar formation—that can end in congestive heart failure, a condition whose mortality rivals that of many common cancers. Because most heart attack patients are older than sixty, while the mice used in preclinical studies are typically around twelve weeks old, the age mismatch has long troubled researchers seeking to translate laboratory findings into human therapies.

The research team, based in Germany, set out to close this gap with an unusually rigorous design. They compared young female C57BL/6 mice aged twelve to thirteen weeks with aged mice aged twenty to twenty-one months, inducing myocardial infarction by permanently ligating the left anterior descending coronary artery. Rather than relying on snapshots, they imaged each animal five days before surgery and again at two, seven, and twenty-eight days afterward, using a seven Tesla small-animal MRI system dedicated to cardiac imaging. This longitudinal cardiac magnetic resonance approach allowed them to track the same hearts over time, capturing end-diastolic and end-systolic volumes, stroke volume, ejection fraction, myocardial mass, and even deformation-based strain parameters with far greater precision than conventional echocardiography.

At baseline, the differences between the age groups were striking. Old mice had significantly larger ventricles and greater stroke volumes, reflecting their bigger bodies, while ejection fractions were similar across groups. Strain analysis—a technique that quantifies how much the heart muscle deforms during contraction—showed numerically higher values in young animals, hinting at greater contractile reserve, though the differences did not reach statistical significance. Statistical modeling confirmed that body weight, rather than age itself, largely explained the baseline differences in chamber volumes and myocardial mass, underscoring how easily confounded such comparisons can be when young and old animals differ so markedly in size.

After the infarction, both groups experienced the expected precipitous drop in ejection fraction within two days, and that impairment persisted through day twenty-eight. Here came the first surprise: young mice showed a steady, progressive decline in ejection fraction over the following weeks, whereas the aged animals’ function, though severely reduced, remained comparatively stable after the initial hit. Yet when the researchers compared the absolute trajectories between groups using linear mixed-effects models, they found no significant age-by-time interaction—meaning that, in raw terms, the two groups deteriorated along broadly similar paths.

The picture changed dramatically once the data were normalized to each animal’s own pre-infarction baseline. Because young mice started with ventricles roughly a third smaller than those of their aged counterparts, the same absolute increase in chamber volume represented a far greater proportional change. On this relative scale, both end-diastolic and end-systolic volumes showed significant effects of age, time, and—crucially—a significant age-by-time interaction, with young mice exhibiting significantly greater dilation at days seven and twenty-eight. Diastolic mass followed a similar pattern, rising about one-and-a-half-fold in young animals by day seven. In other words, the young hearts were not simply remodeling more in absolute terms; they were undergoing a fundamentally larger remodeling burden relative to their starting geometry.

Contractility data told a nuanced story. Feature-tracking strain analysis revealed profound deterioration in all strain parameters—global circumferential, longitudinal, and radial strain—in both groups after infarction, with significant time effects throughout. Only baseline-adjusted global longitudinal strain showed a statistically significant age-by-time interaction, suggesting that this single measure captured a genuinely different post-infarction trajectory between young and old hearts. The authors note that such strain-based metrics, which probe the quality of myocardial deformation rather than gross pumping performance, may be more sensitive indicators of age-dependent remodeling than ejection fraction alone.

Histology added an intriguing layer to the mystery. Scar size, quantified by Masson’s trichrome staining at days seven and twenty-eight, showed no significant differences between age groups, and immunostaining for type V collagen—a protein recently identified as a key regulator of scar maturation—revealed no age-dependent differences in its distribution. But the researchers did identify cell-free necrotic islands within the infarcted tissue, and these were smaller and less numerous in the young mice. This hints at a provocative possibility: young hearts may heal the structural defect faster, yet faster healing does not necessarily translate into better remodeling. Accelerated tissue repair and adverse geometric adaptation, the data suggest, are not the same thing.

The findings directly contradict several influential earlier studies. Work by Bujak and colleagues in 2008, using transient coronary occlusion and echocardiography, found worse dilation and function in aged mice, and Gould’s group had raised similar concerns two decades ago. The authors argue that methodological differences may explain much of the discordance: earlier studies used predominantly male mice, ketamine-xylazine anesthesia, M-mode echocardiography—which is poorly suited to the non-uniform remodeling that follows infarction—and varied infarct models. Notably, the new results align with a recent clinical report showing that younger STEMI patients, despite similar infarct characteristics, were actually more prone to adverse ventricular remodeling than older patients on follow-up cardiac MRI.

The study has limitations the authors acknowledge candidly: only female mice were studied, survival-related selection bias cannot be fully excluded, the permanent ligation model does not capture reperfusion injury as seen in modern clinical care, and the initial ischemic area was not directly measured. Still, the central message stands. This is the first mouse study to characterize age-dependent ventricular remodeling after infarction using longitudinal cardiac magnetic resonance, and it challenges the long-held assumption that aging necessarily amplifies post-infarction remodeling in this model. For a field built largely on twelve-week-old mice, the implication is uncomfortable but clarifying: comparable absolute changes can represent very different biological burdens depending on where the ventricle started, and the young heart’s apparent resilience deserves far more scrutiny than it has received.

Subject of Research: Age-dependent left ventricular remodeling after myocardial infarction in mice assessed by longitudinal cardiac magnetic resonance imaging

Article Title: Young Mice Exhibit Increased Relative Ventricular Remodeling After AMI—A Longitudinal CMR Study

Article References: Lemcke, H., Wörner, P., Dalmer, A., Gäbel, R., Vasudevan, P., Raitza, M., Schweins, M., Lindner, T., Ince, H., Krause, B. J., Vollmar, B., David, R., Meinel, F. G., & Lang, C. I. (2026). Young Mice Exhibit Increased Relative Ventricular Remodeling After AMI —A Longitudinal CMR Study. Aging Cell, 25(10), Article e70748. https://doi.org/10.1111/acel.70748

Image Credits: AI Generated

DOI: 10.1111/acel.70748

Keywords: myocardial infarction, ventricular remodeling, cardiac magnetic resonance, aging, mouse model, ejection fraction, strain analysis, scar formation, collagen type V, heart failure, C57BL/6 mice, cardiac regeneration

The funding will support a one-year feasibility phase of the United States portion of a major international clinical trial designed to answer a deceptively simple question: is aspirin alone sufficient, or is a more intensive combination of blood-thinning medications the better approach for patients with SCAD? The study will be led by the Clinical Trial Center of Mount Sinai Fuster Heart Hospital and the Institute for Transformative Clinical Trials. If the feasibility phase succeeds, Mount Sinai will receive approximately $14 million over seven years from the NIH to launch the larger United States portion of the same trial, an investment that signals how seriously federal funders view the gap in evidence surrounding this disease.

The biological distinction at the heart of the trial is critical to understanding why it matters. In the typical heart attacks that dominate cardiology textbooks and clinical guidelines, the culprit is atherosclerosis — the gradual buildup of cholesterol-laden plaque inside the artery. When that plaque ruptures, platelets in the blood rush to the site and form clots that can completely block the vessel. Standard treatment after such an event relies heavily on antiplatelet medications, which make platelets less likely to stick together and form the clots that could cause a second attack. Decades of randomized trials in this patient population have established how aggressively such therapy should be applied.

SCAD, by contrast, is caused by a problem within the artery wall itself rather than by cholesterol buildup. A tear develops spontaneously in the layers of the vessel, and blood can accumulate within the wall, compressing the channel through which blood flows to the heart. Because the underlying pathology is fundamentally different, the rationale for applying the same intensive antiplatelet regimens is far less clear. Yet doctors have had no large, randomized trial conducted specifically in SCAD patients to guide them, and many of the treatments these patients receive today were developed and validated in entirely different populations. The result is a persistent uncertainty that affects treatment decisions made every day in emergency rooms and cardiac catheterization laboratories around the world.

The stakes are heightened by who SCAD affects. Roughly 80 to 95 percent of cases occur in women, most of whom are between 42 and 52 years old. Many have no traditional cardiovascular risk factors such as high cholesterol or diabetes, which means the condition often arrives without warning and can be mistaken for other causes of chest pain. Because SCAD disproportionately affects women at a relatively young age and without the traditional warning signs of heart disease, the researchers argue that identifying the optimal treatment is particularly important — the goal, as the trial’s leadership describes it, is to determine which treatment provides the best protection while exposing patients to the least unnecessary risk.

Roxana Mehran, MD, Mount Sinai Professor in Cardiovascular Clinical Research and Outcomes at the Icahn School of Medicine, is a Principal Investigator for the trial’s clinical coordinating center. Deepak L. Bhatt, MD, MPH, Director of Mount Sinai Fuster Heart Hospital and also a Principal Investigator of the clinical coordinating center, has emphasized that SCAD is a very different disease from the type of heart attack encountered most often, yet many treatments in use today were adopted from studies conducted in other patient populations. In his view, the trial offers an opportunity to generate the rigorous evidence that patients with SCAD and their physicians have long been waiting for — evidence that could finally place treatment of the condition on the same evidentiary footing as the care of more common heart attacks.

The trial itself, known as SCAD-ALIGN, has been designed to settle the antiplatelet question directly. It will compare a moderate antiplatelet strategy — aspirin alone for three months — against a more intensive strategy consisting of dual antiplatelet therapy for three months followed by nine months of single antiplatelet therapy. Researchers plan to enroll roughly 3,500 patients internationally, with approximately 500 of those in the United States across 60 sites. Participants will be evaluated for major cardiovascular outcomes, including cardiovascular death, myocardial infarction, recurrent SCAD, unplanned coronary revascularization, stroke, transient ischemic attack, and bleeding. That last outcome is especially important, because more aggressive blood thinning always carries an increased risk of hemorrhage, and the trial is structured to capture whether the intensive strategy’s potential benefits outweigh that hazard.

The scale of the effort reflects a fundamental challenge in studying rare diseases. SCAD is relatively uncommon, which means no single center or country can easily enroll enough patients to answer the question reliably. Alan Moskowitz, MD, Professor of Population Health Science and Policy at the Icahn School of Medicine and a Principal Investigator for the trial’s data coordinating center, has noted that the project brings together research networks and national funding organizations across multiple countries under one common study protocol. Annetine Gelijns, PhD, Chair of the Department of Population Health Science and Policy and a Principal Investigator for the data coordinating center, has added that the trial is expected to represent a novel model of international academic collaboration and to provide the first large-scale randomized evidence to help guide antiplatelet therapy in this patient population.

The collaborative architecture extends well beyond the United States. SCAD-ALIGN was endorsed by the Multinational Clinical Trials Initiative of the Global Cardiovascular Research Funders Forum, and the global collaboration includes investigators and funding organizations from the United States, Germany, the United Kingdom, Canada, the Netherlands, Denmark, Sweden, Spain, Australia, New Zealand, and other participating countries, with additional participation from centers in South America. Emilia Bagiella, PhD, Director of the Center for Biostatistics in the Department of Population Health Science and Policy and a Principal Investigator for the data coordinating center, has described this coordinated approach as intended to generate robust evidence for an important clinical question that affects women disproportionately and for which large-scale industry-sponsored research has been limited — a candid acknowledgment that commercial incentives have historically underserved conditions like SCAD.

For the patients and physicians who have navigated SCAD without the benefit of dedicated trial evidence, the launch of this feasibility phase marks a turning point. The condition’s rarity, its predilection for young and otherwise healthy women, and its fundamentally distinct mechanism have long combined to leave clinicians extrapolating from data that were never meant to apply to these patients. If the feasibility phase demonstrates that the international network can recruit and follow participants at the required scale, the full trial will proceed with the backing of approximately $14 million in NIH support over seven years, and the results could ultimately reshape treatment recommendations for SCAD patients worldwide — replacing inherited convention with evidence earned from the very population the disease affects most.

Subject of Research: An international randomized clinical trial comparing antiplatelet treatment strategies for spontaneous coronary artery dissection, a heart attack cause that predominantly affects young women.

Article Title: Mount Sinai awarded $2 million to launch international clinical trial on spontaneous coronary artery dissection

Article References: Mount Sinai awarded $2 million to launch international clinical trial on spontaneous coronary artery dissection. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: SCAD, spontaneous coronary artery dissection, Mount Sinai, NIH, clinical trial, antiplatelet therapy, aspirin, women's heart health, cardiology, SCAD-ALIGN, heart attack, dual antiplatelet therapy

The scale of the undertaking is what sets this research apart. Led by Eugenio Traini of the Netherlands Organisation for Applied Scientific Research and colleagues, the team assembled a cohort of 10,156,661 people aged 30 and older who were registered at a Dutch address on 1 January 2012. Rather than relying on sparse monitoring stations, the researchers used LOTOS-EUROS, an open-source chemistry transport model that simulates atmospheric chemistry, transport and deposition to estimate PM2.5 concentrations at a resolution of roughly two by two kilometres, every hour, across the entire country from 2006 to 2019. Those gridded estimates were aggregated to postal code areas and linked to each participant’s residential history, allowing the team to follow people as they moved through landscapes of shifting air quality.

PM2.5 refers to airborne particles smaller than 2.5 micrometres across, roughly a thirtieth of the width of a human hair. These particles are emitted directly from burning solid fuels, road transport and industry, or formed secondarily in the atmosphere from precursor emissions such as ammonia from agriculture and sulphur compounds from shipping. Because of their tiny size, they evade the lungs’ defences, penetrate deep into the respiratory tract, and can enter the bloodstream, where they trigger systemic inflammation, oxidative stress and vascular dysfunction. In the Netherlands, average annual concentrations fell from about 20 micrograms per cubic metre in 2006 to 13 micrograms per cubic metre in 2019, a decline reflecting European and national clean-air policies, yet the study suggests that these remaining, lower levels continue to exact a measurable toll.

The researchers tracked first-time hospitalisations for three cardiovascular outcomes: ischaemic heart disease, myocardial infarction, and stroke, together with a composite outcome capturing the first hospitalisation for any cardiovascular cause. Over the follow-up period ending in 2019, the cohort recorded 437,089 incident ischaemic heart disease hospitalisations, 205,663 strokes and 151,345 heart attacks, totalling 592,259 first cardiovascular hospitalisations. Because modelling time-varying exposure across ten million people is computationally punishing, the team used a nested case-control design: each person hospitalised was matched with four controls of the same sex and exact age who were still event-free at the moment of the case’s admission, a technique known to yield estimates comparable to full cohort analyses.

The short-term findings show how quickly dirty air can tip vulnerable patients into crisis. In fully adjusted models, a 10 microgram per cubic metre increase in PM2.5 averaged over the six days preceding admission was associated with a 5.8 percent higher risk of hospitalisation for ischaemic heart disease, a 5.3 percent higher risk for myocardial infarction, and a 4.7 percent higher risk for a first cardiovascular hospitalisation overall. Even exposure on the day of admission itself, lag zero, carried elevated odds. Stroke was the exception: its estimates pointed in a positive direction but the confidence intervals crossed the null, meaning the acute association could not be confirmed statistically in this population.

The most sophisticated part of the analysis went beyond simple averages. Using distributed lag models, a statistical framework that estimates how risk is distributed across each individual day or year of past exposure, the researchers uncovered distinct temporal fingerprints for each condition. For ischaemic heart disease, the risk signal was clearest in the one to six days immediately before hospitalisation, consistent with the idea that pollution can acutely trigger events in people whose arteries are already compromised. For myocardial infarction, the effect emerged beginning one day after exposure. For stroke, however, a suggestive increase in risk appeared two to three weeks before admission, hinting that cerebrovascular events may follow more prolonged inflammatory and coagulation pathways rather than an immediate trigger.

The long-term results were even more striking in magnitude. A 10 microgram per cubic metre increase in annual PM2.5 averaged over the two years spanning the hospitalisation year and the year before was associated with a 39.8 percent higher risk of ischaemic heart disease admission, a 22.2 percent higher risk of stroke, a 13.4 percent higher risk of heart attack, and a 32.5 percent higher risk of a first cardiovascular hospitalisation overall. Distributed lag analysis showed that risk rose with cumulative exposure up to roughly three years before hospitalisation for ischaemic heart disease and the composite outcome, then plateaued or declined. For heart attack, the cumulative effect peaked around four years before admission. These estimates are larger than those reported in some earlier European studies, possibly because the time-varying exposure assignment reduced misclassification compared with the common practice of anchoring exposure to a single baseline year.

Several mechanisms and caveats frame how these numbers should be read. Effect estimates were consistently slightly higher in men than women, and higher among people aged 65 and older than those aged 30 to 64, though the differences were modest. Sensitivity analyses in a subset of about 305,000 participants with lifestyle data on smoking, alcohol, body mass index and education broadly supported the main results, although with wider uncertainty due to the smaller sample. The study adjusted extensively for individual socioeconomic factors such as income, civil status and country of origin, plus neighbourhood-level indicators including urbanisation and deprivation, and estimates attenuated with adjustment while remaining consistently positive. The authors note that their exposure model explained 72 percent of the variance in monitored concentrations, meaning residual prediction error could blur some lag-specific findings, and that hospitalisation registry completeness declined over part of the study period, a form of misclassification that would likely push the true effects down rather than up.

The researchers also caution that the analysis focused on PM2.5 alone and did not disentangle correlated co-pollutants such as nitrogen dioxide and ozone, which would require multipollutant mixture methods still under active methodological development. Nor did it capture exposures outside the home, at workplaces or during commuting, which would tend to understate rather than exaggerate the true associations. Looking ahead, the LOTOS-EUROS framework offers a promising capability the study did not yet exploit: source apportionment, or attributing particulate mass to specific emitters such as agriculture, industry and traffic, which could reveal which sources drive the greatest cardiovascular harm.

The message that emerges is sobering for a country that has largely cleaned up its air. Average Dutch PM2.5 levels were moderate by European standards and fell steadily throughout the study, yet both short bursts and years of accumulated exposure were consistently linked to hospitalisations at concentrations well below the World Health Organization’s historical guideline limits, echoing pooled European evidence that found no clear threshold below which cardiovascular effects vanish. The outcome-specific timing, acute for coronary events, more drawn-out for stroke, argues for epidemiological studies that treat exposure as a living, changing history rather than a single snapshot. For policymakers, the findings suggest that further reductions in fine particulate pollution, even from already low baselines, would translate directly into fewer heart attacks, strokes and cardiac hospital beds filled.

Subject of Research: Associations between short- and long-term exposure to ambient PM2.5 and cardiovascular disease hospitalisation in a nationwide Dutch cohort

Article Title: Short- and long-term exposure to ambient PM 2.5 and risk of cardiovascular disease hospitalisation: A nationwide cohort study in the Netherlands

Article References: Traini, E., Shen, Y., de Crom, T. O., Pekel, F., Henzing, B., Zhang, J. J., Pseftogkas, A., Ge, C., Timmermans, R., & Pronk, A. (2026). Short- and long-term exposure to ambient PM2.5 and risk of cardiovascular disease hospitalisation: A nationwide cohort study in the Netherlands. Environmental Advances, 26, Article 100756. https://doi.org/10.1016/j.envadv.2026.100756

Image Credits: AI Generated

DOI: 10.1016/j.envadv.2026.100756

Keywords: PM2.5, air pollution, cardiovascular disease, heart attack, stroke, ischaemic heart disease, hospitalisation, Netherlands, distributed lag models, LOTOS-EUROS, cohort study, environmental health

The molecular logic of the HIF pathway is elegant. Under normal oxygen tensions, the alpha subunits of HIF, chiefly HIF1α and HIF2α, are continuously marked for destruction by prolyl hydroxylase domain enzymes, EGLN1 and EGLN2, which require molecular oxygen to hydroxylate specific proline residues. Once hydroxylated, the alpha subunits are captured by the von Hippel–Lindau ubiquitin ligase complex and rapidly degraded by the proteasome. When oxygen falls during ischaemia, hydroxylation stalls, HIFα accumulates within minutes, translocates to the nucleus, dimerizes with the constitutive ARNT subunit, and binds hypoxia response elements to switch on hundreds of hypoxia-responsive genes. Importantly, the review highlights that during reperfusion HIFs can remain stabilized even after oxygen returns, because ischaemic accumulation of Krebs cycle metabolites such as succinate inhibits prolyl hydroxylase activity, providing oxygen-independent stabilization that prolongs the transcriptional response precisely when injury is peaking.

Among the best-characterized HIF-dependent programmes is metabolic reprogramming. HIF1α induces pyruvate dehydrogenase kinase, which shunts pyruvate away from oxygen-hungry mitochondrial oxidation and towards glycolysis, a metabolic switch that allows cardiomyocytes to generate ATP with far less oxygen consumption. Experimental work shows that HIF1α also targets the mitochondrial permeability transition pore, a critical gatekeeper of reperfusion-induced cell death, thereby blunting the lethal calcium and reactive-oxygen-driven opening of this pore when blood flow resumes. More recently, glycolytic flux has been linked to epigenetic regulation through histone lactylation, in which lactate-derived modification of histones activates reparative gene programmes after infarction, suggesting that the metabolic shift driven by HIFs does more than produce energy; it rewires the gene-expression landscape of the injured heart toward survival and repair.

A second major axis of HIF-mediated cardioprotection involves extracellular adenosine signalling. Hypoxia-inducible factors upregulate ecto-5′-nucleotidase, or CD73, the enzyme that converts released AMP into adenosine, while simultaneously repressing adenosine kinase and equilibrative nucleoside transporters, thereby boosting extracellular adenosine concentrations at the very moment the heart needs them. Adenosine acting through A2A and A2B receptors on immune cells, endothelium and cardiomyocytes dampens inflammation, preserves microvascular barrier integrity and promotes tolerance to ischaemic stress. The review also details HIF2α-dependent induction of amphiregulin, a ligand that engages epidermal growth factor receptor pathways to reduce myocardial injury, and transcription-independent induction of ERBB1, illustrating that HIFs protect the heart through both classical gene transcription and rapid non-genomic mechanisms.

The two major HIF alpha isoforms are not interchangeable. HIF1α predominantly drives core hypoxic metabolism genes and is the dominant isoform in cardiomyocytes during acute ischaemia, whereas HIF2α has more restricted cell-type expression, prominent in endothelial cells, macrophages and stromal populations, and controls a partly distinct transcriptional portfolio involving growth factor signalling, angiogenesis, macrophage polarization and microRNA induction. Gene-targeting studies show that deleting HIF1α in cardiomyocytes abolishes preconditioning-induced protection, while HIF2α deletion in myeloid or endothelial compartments separately compromises repair and barrier function. The review emphasizes that this isoform specificity carries a cautionary message for drug development: blanket HIF activation may simultaneously trigger beneficial and detrimental programmes depending on which cell types and which isoforms are engaged, and precise tuning of prolyl hydroxylase inhibition may be key to maximizing benefit.

Perhaps the most compelling clinical framing of the HIF story comes from ischaemic preconditioning and its clinically translatable cousin, remote ischaemic conditioning. The landmark discovery that brief, repeated episodes of ischaemia dramatically protect the heart against subsequent prolonged ischaemia established that the myocardium possesses an endogenous survival programme waiting to be triggered. Multiple studies now demonstrate that HIF1 is required for this protection: mice with partial HIF1α deficiency lose preconditioning-induced cardioprotection entirely, and HIF1 is also indispensable for remote preconditioning, in which transient limb ischaemia protects the heart through circulating humoral and neural signals. Mechanistically, remote conditioning engages EGLN1 inhibition and metabolite rerouting, and downstream protection involves adenosine signalling, interleukin-10 induction and HIF-dependent metabolic adaptation, providing a molecular explanation for one of cardiology’s most studied protective interventions.

The review also weaves in a surprising temporal dimension: the circadian clock. Clinical observations spanning decades show that the incidence and severity of myocardial infarction vary by time of day, and recent work demonstrates that the clock component BMAL1 can partner with HIF2α to form a functional heterodimer that modulates circadian variation in myocardial injury susceptibility. The PER2 protein, stabilized through adenosine A2B receptor signalling, promotes a HIF-dependent metabolic switch crucial for myocardial adaptation to ischaemia, while rhythmic oxygen fluctuations themselves reset circadian clocks through HIF1α. This reciprocal crosstalk between hypoxia sensing and circadian biology suggests that the timing of a heart attack, of cardiac surgery, or even of drug administration could meaningfully influence how much myocardium survives, opening the emerging field of circadian cardioprotective medicine.

What elevates this basic science into immediate translational territory is the fact that pharmacological HIF stabilizers already exist and are in clinical use. Oral inhibitors of HIF prolyl hydroxylases, including roxadustat, vadadustat, daprodustat, molidustat and enarodustat, have been approved or evaluated extensively for treating renal anaemia, because stabilizing HIF stimulates erythropoietin production and iron utilization. The review argues that this existing clinical infrastructure provides a ready-made pathway for evaluating HIF activation as a cardioprotective strategy in myocardial infarction, cardiac surgery and myocardial injury after non-cardiac surgery, the latter being a common and under-recognized cause of perioperative morbidity. Preclinical studies support this optimism: roxadustat markedly reduces myocardial ischaemia–reperfusion injury in mouse models, attenuates adverse remodelling after infarction, and protects diabetic myocardium by upregulating HIF1α-dependent antioxidant programmes.

The authors are careful to note the caveats. Chronic HIF activation carries risks, including pro-angiogenic effects relevant to cancer biology, erythrocytosis, and context-dependent inflammatory consequences, as illustrated by HIF2α gain-of-function syndromes and by the oncology use of the HIF2 antagonist belzutifan. Cardiovascular safety signals from the anaemia trials have been scrutinized, and the review stresses that acute, time-limited, precisely dosed HIF activation around the window of ischaemia and reperfusion is the cardioprotective concept, distinct from indefinite chronic therapy. Nevertheless, the convergence of mechanistic depth, isoform and cell-type knowledge, clinically validated small molecules and proven preconditioning paradigms positions HIF biology as one of the most plausible near-term routes to a therapy that has eluded cardiology for decades: reliably limiting the damage that both the blockage and the rescue inflict on the human heart.

The epidemiological backdrop gives this translational urgency its weight. Ischaemic heart disease remains the leading cause of death worldwide, and analyses from the Global Burden of Disease project document its continued expansion as populations age, while economic studies in the European Union attribute tens of billions of euros in annual costs to cardiovascular disease. Within surgical practice, elevated high-sensitivity troponin after non-cardiac surgery is associated with increased thirty-day mortality, making perioperative myocardial injury a target population in which a short-acting cardioprotective drug could be deployed prophylactically, before the ischaemic insult even occurs.

Historically, the field owes much to the foundational work of Gregg Semenza and colleagues, who in the early 1990s demonstrated cell-type-specific, hypoxia-inducible expression of the erythropoietin gene and subsequently purified hypoxia-inducible factor 1 as an oxygen-regulated heterodimer. The mechanistic resolution came in 2001, when parallel studies showed that oxygen sensing is achieved through prolyl hydroxylation of HIFα and its recognition by the von Hippel–Lindau ubiquitin ligase machinery, a discovery recognized with the 2019 Nobel Prize in Physiology or Medicine shared by Semenza and Peter Ratcliffe, alongside William Kaelin. That oxygen-sensing pathway is precisely what today’s oral prolyl hydroxylase inhibitors exploit.

The preconditioning literature adds an instructive dose of realism. Despite decades of robust animal data, attempts to translate conditioning paradigms into routine clinical practice have yielded mixed results, often attributed to species differences, comorbidities such as diabetes that blunt endogenous protective signalling, and concomitant medications including statins and opioids that engage overlapping pathways. The HIF framework offers a potential remedy: rather than relying on the body’s variable endogenous trigger, pharmacological stabilization of HIF could impose the protective programme directly, and preclinical work in diabetic models suggests that HIF1α-dependent antioxidant induction may restore protection where conditioning fails.

For clinicians watching this space, the near-term research agenda is discernible. The review points toward carefully designed trials of acute, time-limited HIF activation in the peri-infarct and perioperative windows, with attention to dosing, timing relative to reperfusion, and isoform-selective engagement. Whether the anaemia drugs can be repurposed at cardioprotective doses without erythrocytosis or vascular risks will determine if this long-sought therapy finally reaches the bedside.

Subject of Research: The role of hypoxia-inducible factors in myocardial ischaemia–reperfusion injury and cardioprotection

Article Title: The role of hypoxia-inducible factors in myocardial ischaemia–reperfusion injury and cardioprotection

Article References: Luo, C., Li, T., Tak, J., DeBerge, M., Tsai, K.-L., & Eltzschig, H. K. (2026). The role of hypoxia-inducible factors in myocardial ischaemia–reperfusion injury and cardioprotection. Nature Reviews Cardiology. https://doi.org/10.1038/s41569-026-01339-y

Image Credits: AI Generated

DOI: 10.1038/s41569-026-01339-y

Keywords: hypoxia-inducible factors, myocardial ischaemia-reperfusion injury, cardioprotection, HIF1α, HIF2α, prolyl hydroxylase inhibitors, ischemic preconditioning, adenosine signaling, glycolytic metabolism, circadian rhythm, roxadustat, heart attack