Background: End-stage heart failure (HF) is refractory to current standard medical therapy, and the number of donor hearts is insufficient to meet the demand for transplantation. Recent studies suggest autologous stem cell therapy may regenerate cardiomyocytes, stimulate neovascularization, and improve cardiac function and clinical status. Although human fetal-derived stem cells (HFDSCs) have been studied for the treatment of a variety of conditions, no clinical studies have been reported to date on their use in treating HF. We sought to determine the efficacy and safety of HFDSC treatment in HF patients.
Methods and results: Direct myocardial transplantation of HFDSCs by open-chest surgical procedure was performed in 10 patients with HF due to nonischemic, nonchagasic dilated cardiomyopathy. Before and after the procedure, and with no changes in their preoperative doses of medications (digoxin, furosemide, spironolactone, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, betablockers), patients were assessed for New York Heart Association (NYHA) class, performance in the exercise tolerance test (ETT), ejection fraction (EF), left ventricular end-diastolic dimension (LVEDD) via transthoracic echocardiography, performance in the 6-minute walk test, and performance in the Minnesota congestive HF test. All 10 patients survived the operation. One patient had a stroke 3 days after the procedure, and although she later recovered, she was unable to perform the follow-up tests. Another male patient experienced pericardial effusion 3 weeks after the procedure. Although it resolved spontaneously, the patient abandoned his control tests and died 5 months after the procedure. An autopsy of the myocardium suggested that new young cells were present in the cardiomyocyte mix. At 40 months, the mean (+/-SD) NYHA class decreased from 3.4 +/- 0.5 to 1.33 +/- 0.5 (P = .001); the mean EF increased 31%, from 26.6% +/- 4% to 34.8% +/- 7.2% (P = .005); and the mean ETT increased 291.3%, from 4.25 minutes to 16.63 minutes (128.9% increase in metabolic equivalents, from 2.46 to 5.63) (P < .0001); the mean LVEDD decreased 15%, from 6.85 +/- 0.6 cm to 5.80 +/- 0.58 cm (P < .001); mean performance in the 6-minute walk test increased by 43.2%, from 251 +/- 113.1 seconds to 360 +/- 0 seconds (P = .01); the mean distance increased 64.4%, from 284.4 +/- 144.9 m to 468.2 +/- 89.8 m (P = .004); and the mean result in the Minnesota test decreased from 71 +/- 27.3 to 6 +/- 5.9 (P < .001).
Conclusion: Although these initial findings suggest direct myocardial implantation of HFDSCs is feasible and improves cardiac function in HF patients at 40 months, more clinical research is required to confirm these observations.