Mitochondrial function and coronary flow reserve improvement after autologous myoblast patch transplantation for ischaemic cardiomyopathy: a case report

BACKGROUND: Autologous myoblast patch (AMP) transplantation has resulted in good clinical outcomes for end-stage ischaemic cardiomyopathy, but the mechanisms behind them are unclear. Herein, we report the relationship between mitochondrial function and coronary flow reserve (CFR) before and after AMP transplantation. CASE SUMMARY: The patient was a 73-year-old man who underwent coronary artery bypass grafting (CABG). At that time, the left ventricular ejection fraction (LVEF) was 53%, but it declined to 25% after 6 years. He was diagnosed with ischaemic cardiomyopathy (ICM). Coronary flow reserve in NH(3)-positron emission tomography (NH(3)-PET) was impaired to 1.69. In Tc-99m MIBI scintigraphy, the washout rate (WR) was 17%, suggestive of impaired mitochondrial function. He was not a candidate for heart transplantation, and we performed AMP transplantation 6 years after CABG. One year after AMP transplantation, LVEF, CFR, and Tc-99m MIBI WR improved to 36%, 2.07, and 7%, respectively. The Tc-99m MIBI WR improved especially in the anterolateral region, and the CFR increased in almost all segments. DISCUSSION: In this case, AMP transplantation for ICM improved cardiac function, CFR, and mitochondrial function. The mitochondrial transfer from the transplanted myoblasts to the damaged myocardium may have contributed to the mitochondrial function improvement. This probably induced myocardial energy metabolism recovery and decreased oxygen demand. AMP transplantation also has the potential to improve microvascular dysfunction, due to angiogenesis induction. These effects can lead to improved prognoses of ICM after AMP transplantation, highlighting its potential to cure refractory heart failure.