The trial is scheduled to begin in 2027 at Keck Hospital of USC in partnership with the USC Cardiac and Vascular Institute. A second clinical site will be established at the University of Washington, where elements of the technology were originally developed. The first phase will enroll approximately 18 patients who have experienced extensive myocardial infarction, the medical term for a heart attack that destroys part of the heart’s muscular wall.

Patients in the study will receive stem-cell-derived heart muscle cells delivered into regions damaged by the infarction. The primary goals will be to evaluate safety and determine whether the procedure is feasible in people with severe cardiac injury. Investigators will also monitor early biological signals, including whether the transplanted cells remain active, integrate with the injured tissue and produce measurable changes in cardiac performance during recovery and long-term follow-up.

A heart attack occurs when blood flow through a coronary artery is blocked, depriving cardiac muscle of oxygen. Within minutes, cells in the affected region begin to die, and the resulting scar tissue lacks the contractile properties of healthy myocardium. Unlike tissues such as skin or blood, adult human heart muscle has only a limited capacity for self-repair. As a result, a large infarction can weaken the heart’s pumping function, increase the risk of heart failure and leave survivors unable to perform ordinary activities without fatigue or breathlessness.

Current cardiovascular treatments can reopen blocked arteries, limit further injury and help the remaining heart muscle work more efficiently. They cannot, however, routinely replace the cardiomyocytes that have already been lost. Murry’s research program is aimed at addressing that biological gap by producing replacement heart muscle cells in the laboratory and delivering them directly to damaged tissue. The strategy represents a shift from supporting a failing heart to attempting to rebuild part of its contractile apparatus.

The transplanted cells are being developed as a form of cellular therapy, in which living cells act as the therapeutic agent rather than serving merely as a vehicle for a drug. According to Murry, the cells are intended to become active within the injured heart, contribute to repair and synchronize with surrounding muscle. Achieving that outcome requires more than placing new cells into scarred tissue: the cells must survive, connect functionally with the host myocardium and avoid creating dangerous electrical disturbances or abnormal rhythms. The initial trial is therefore designed principally to establish safety before testing therapeutic effectiveness in larger patient groups.

The foundation’s funding will also support research into the immune response triggered by cell transplantation. Even cells created from stem cells can be recognized as foreign by the recipient’s immune system, potentially leading to inflammation or destruction of the transplanted population. Patients who receive cellular grafts may consequently require immunosuppressive drugs, which can increase susceptibility to infection and produce other long-term complications. Researchers will study how immune cells interact with the implanted cardiac cells and investigate methods that could reduce or eventually eliminate the need for chronic immunosuppression.

The work builds on approximately three decades of research by Murry and his collaborators to move regenerative cardiology from laboratory experiments toward clinical treatment. The program includes gene-edited cellular technology, intended to improve the compatibility or performance of therapeutic cells in the human body. The precise effectiveness of the approach will not be known until it is tested in patients, and the small 2027 cohort will not be large enough to determine whether the therapy improves survival or prevents heart failure. Those questions would require subsequent trials involving substantially more participants and longer observation.

The Marcus Foundation described the project as a potential turning point for regenerative medicine, while USC leaders said the investment could create a platform for developing additional cellular therapies. The immediate scientific challenge is to determine whether transplanted heart muscle cells can be delivered safely and function meaningfully within severely damaged human hearts. If the trial meets its safety and feasibility objectives, it could provide the clinical evidence needed to advance a new generation of treatments for myocardial infarction—therapies designed not only to help patients live with damaged cardiac tissue, but to restore some of the function that conventional medicine cannot yet replace.

Subject of Research: Stem cell-based regenerative therapy for heart muscle damaged by myocardial infarction

Article Title: $28.7 Million Award Supports USC Trial of Stem Cell Therapy to Regenerate Heart Muscle After Heart Attack

Web References: The Marcus Foundation: https://marcusfoundation.org/; USC Stem Cell Center: https://stemcell.keck.usc.edu/; Chuck Murry Lab: https://murrylab.usc.edu/charles-chuck-murry-md-phd/; USC Cardiac and Vascular Institute: https://www.keckmedicine.org/services/cardiovascular/; Keck School of Medicine of USC: https://keck.usc.edu/

Image Credits: Steve Cohn

Keywords: Heart disease, myocardial infarction, heart attack, heart muscle, stem cell research, stem cell therapy, cell therapy, regenerative medicine, cardiovascular disorders, heart failure, clinical trial, cardiac regeneration

Stem cell-based therapies offer unprecedented potential to repair heart damage caused by myocardial infarction, primarily through the regeneration of functional cardiac muscle cells. Human pluripotent stem cell-derived cardiomyocytes, specifically, possess the ability to engraft and electrically couple with native myocardium, thereby restoring contractile function. However, a critical barrier to clinical translation has been the limited survival of transplanted cells, compounded by the inability to robustly monitor these cells over extended durations in vivo. Traditional imaging modalities have fallen short, either due to incompatibility with larger animal models or the transient nature and ambiguity of labeling signals that degrade as cells proliferate or engage the host immune response.

Addressing these limitations, Professor Hai-Ling Margaret Cheng and her team engineered a state-of-the-art imaging platform integrating the overexpression of ferritin, an intracellular iron-storage protein, within human pluripotent stem cells. By genetically modifying these cells to upregulate ferritin, the researchers endowed the cardiomyocytes with an intrinsic MRI contrast capability. This molecular engineering ensures that the iron sequestered by ferritin generates a distinct and enhanced signal under MRI, especially when augmented with manganese chloride administration, which induces a bright contrast, thus enabling three-dimensional spatial mapping of the surviving transplanted cells.

Critically, extensive in vitro characterization of these ferritin-overexpressing cardiomyocytes confirmed preservation of essential cellular phenotypes including normal architecture, contractile protein expression, and electrophysiological properties. Such validation underscores that the genetic modification does not compromise the fundamental cardiac functions requisite for therapeutic efficacy. Subsequently, the team transplanted the engineered cells into the left ventricular myocardium of immunodeficient rat models, both healthy and with induced cardiac injury, to emulate clinically relevant conditions.

Utilizing high-resolution MRI scanners, the researchers longitudinally tracked these cells over an eight-week period, a duration that surpasses typical tracking intervals recorded in previous studies. The administration of manganese chloride played a pivotal role in amplifying the ferritin-related MRI signal, facilitating the precise localization and persistence mapping of viable transplanted cells in living subjects. Post-mortem histological analyses corroborated the imaging data, confirming that the bright signals corresponded to genuine cell survival rather than artifacts or nonspecific uptake. Additionally, echocardiographic evaluation demonstrated that manganese treatment did not adversely affect cardiac function, affirming the safety profile of this imaging adjunct.

This technique answers a long-standing need in regenerative medicine by enabling clinicians and researchers to non-invasively visualize therapeutic cell engraftment with high spatial and temporal resolution. The ability to discern not only the presence but also the precise anatomical distribution of surviving stem cell-derived cardiomyocytes offers invaluable insights into mechanisms of cell survival, migration, and integration within host tissue microenvironments. Such knowledge is paramount for devising strategies to enhance engraftment efficiency and to tailor therapeutic interventions.

Professor Cheng emphasized the transformative implications of this technology, highlighting that the field has historically grappled with the ephemeral nature of cell tracking signals and insufficient imaging sensitivity. The bright ferritin MRI platform fundamentally overcomes these bottlenecks by providing sustained, high-contrast visualization that endures as long as transplanted cells live. This leap forward equips stem cell scientists with a powerful investigative tool to systematically optimize therapeutic protocols grounded in real-time, in vivo data.

Looking ahead, the research team aims to leverage this imaging modality to systematically refine stem cell therapies, seeking to identify molecular and environmental determinants that maximize cell survival post-transplantation. By harnessing the detailed spatiotemporal data acquired through bright ferritin MRI, future studies can elucidate the biological barriers hindering cell persistence and integration, ultimately accelerating the translation of durable and efficacious cardiac regeneration treatments.

Moreover, the broader applicability of this approach suggests it could be adapted to other stem cell-based interventions targeting diverse tissues, where monitoring therapeutic cell fate remains a critical challenge. The integration of genetic ferritin tagging with manganese-enhanced MRI represents a versatile and non-invasive platform that could redefine how regenerative therapies are evaluated and optimized across medical disciplines.

This study, published in the journal Magnetic Resonance in Medicine, represents a pioneering milestone in biomedical imaging and regenerative cardiology. It not only advances the technical frontier of cell tracking technologies but also lays the groundwork for translational efforts poised to improve outcomes for patients suffering from heart disease worldwide. The intersection of molecular engineering and advanced imaging embodied in this work exemplifies the innovative spirit driving contemporary biomedical research.

As the global burden of cardiovascular disease continues to rise, such innovative solutions are essential to overcome existing therapeutic gaps. The bright ferritin MRI technique symbolizes a beacon of hope, illuminating the path toward precision stem cell therapies with reliably quantifiable outcomes. Continued exploration and refinement of this technology promise to catalyze new horizons in personalized medicine and regenerative health.

Subject of Research: Tracking of transplanted human pluripotent stem cell-derived cardiomyocytes in heart tissue using advanced MRI techniques.

Article Title: Bright Ferritin MRI Enables Long-Term Visualization of Stem Cell-Derived Cardiomyocyte Survival in Rat Hearts

Web References: 10.1002/mrm.70316

References: Published in Magnetic Resonance in Medicine

Image Credits: Photo by Tim Fraser, KITE Studio

Keywords

Magnetic resonance imaging, cardiomyocytes, pluripotent stem cells, ferritin, manganese-enhanced MRI, cell tracking, regenerative cardiology, stem cell therapy, heart regeneration, cell survival monitoring, molecular imaging, biomedical engineering