Stem Cell Therapy Shows Promise in Reducing Heart Failure Risk After STEMI, But Challenges Remain
A novel approach using stem cell infusions after a common heart procedure may significantly lower the risk of heart failure, but experts caution that further research is needed to solidify its place in standard cardiac care. Results from the PREVENT-TAHA8 study, published October 29, 2025, in The BMJ, indicate a substantial reduction in heart failure incidence among patients receiving an intracoronary infusion of stem cells following percutaneous coronary intervention (PCI) for acute STEMI.
The study revealed that at three years, only 5.74% of patients treated with mesenchymal cells – derived from Wharton’s jelly, a connective tissue rich in stem cells found in the umbilical cord – either developed heart failure or were readmitted to the hospital for the condition. This contrasts sharply with a 16.08% rate observed in patients receiving standard care alone.
Researchers led by Armin Attar, MD, PhD, of Shiraz University of Medical Sciences in Iran, concluded that their findings “position [mesenchymal stem cells] as a viable adjunctive procedure to mitigate myocardial infarction-induced heart failure.” They theorize that the beneficial effects stem from the anti-inflammatory properties of these cells, a hypothesis supported by earlier research, including the DREAM-HF trial, which demonstrated a reduction in reinfarction risk with subendocardial mesenchymal stem cell transplantation in heart failure patients with elevated C-reactive protein levels.
The PREVENT-TAHA8 trial also provided valuable insights into the impact of stem cell therapy on left ventricular ejection fraction (LVEF). Patients in the treatment group experienced approximately a 6% greater improvement in LVEF at six months compared to the control group (P < 0.001).
However, despite the encouraging results, the path to widespread adoption isn’t straightforward. A leading cardiologist commenting on the study emphasized that the field has learned from past disappointments with stem cell therapies. “Researchers have evolved their thinking based on numerous failed past studies of stem cell therapy,” he stated.
Specifically, the type of stem cell used may be crucial. Mesenchymal cells, he suggested, appear more promising for intracoronary delivery than bone marrow mononuclear cells, which often “fly through the heart” without exerting a therapeutic effect. The anti-inflammatory mechanism of action also appears to be a key factor, and replication of these findings in larger trials is essential.
“Stem cells in general have gotten a bad name in a way because we certainly overpromised, based on the earlier studies, and we have underdelivered dramatically,” the cardiologist added. While acknowledging that PREVENT-TAHA8 doesn’t represent a dramatic breakthrough, he expressed hope that it could reinvigorate research into safe and cost-effective stem cell therapies. He posited that preventing even a single heart failure hospitalization with a single infusion could justify the cost.
The PREVENT-TAHA8 study involved 396 patients (average age 59 years; 19% women) randomized across three teaching hospitals in Iran. Over 60% of participants had a history of smoking, 44% had hypertension, and roughly one-third had hypercholesterolemia. All patients had undergone PCI for acute STEMI, with the left anterior descending (LAD) artery as the infarct-related artery, and had LVEF rates below 40%. The intervention group received the stem cell infusion within 3 to 7 days of PCI, in addition to guideline-directed medical therapy (GDMT), while the control group received GDMT alone.
The study demonstrated a statistically significant reduction in the incidence of heart failure in the stem cell therapy group (2.77 vs. 6.48 per 100 person-years; HR 0.43; 95% CI 0.21-0.89) and in heart failure readmissions (0.92 vs. 4.20 per 100 person-years; HR 0.22; 95% CI 0.06-0.74). The composite endpoint of cardiovascular mortality and myocardial infarction was also significantly lower in the stem cell-treated group (HR 0.39; 95% CI 0.19-0.82). Notably, no significant differences were observed between the groups regarding readmission for MI, all-cause mortality, or cardiovascular mortality.
Attar and his colleagues emphasize the need for further phase I and II studies to optimize stem cell type, isolation techniques, and delivery strategies for cardiac regeneration. They also highlight the importance of prioritizing clinical endpoints in future trials, rather than relying on surrogate endpoints as many previous studies have done, to provide definitive evidence of patient benefit.
However, challenges remain. “The issue is that right now what you’re seeing is a lot of single sites or small consortiums doing these studies,” one expert noted, expressing skepticism about a widespread resurgence of cell therapy. He cited the high cost of development and clinical trials, as well as the growing focus on anti-inflammatory drugs as a competing strategy for mitigating post-MI inflammation.
“There’s also still some skepticism out there, and I think it’s fairly well founded,” he concluded, acknowledging the need for robust, large-scale trials to validate these promising early findings.
