Heart patches from human stem cells aid pigs’ recovery after MI

Patches of human cardiac muscle made from pluripotent stem cells helped the hearts of pigs recover after myocardial infarction (MI), according to a first-of-its-kind study in large animals published in Circulation.

The researchers believe their study is another step toward treating human heart attacks with cardiac muscle patches, which can cover the area affected by MI and potentially reduce the risk of heart failure associated with dead heart muscle.

Notably, the heart patches in this study weren’t associated with an increase in arrhythmias, a complication observed in previous studies of cardiomyocytes generated from stem cells.

Thirteen pigs in the study received two human cardiac muscle patches (hCMPs), 14 were treated with cell-free open fibrin patches, 15 were left untreated and eight received a sham surgery.

Each hCMP was 4 by 2 centimeters and nearly the thickness of a dime, according to a press release from the University of Alabama at Birmingham (UAB). They were a combination of four million cardiomyocytes, two million endothelial cells and two million smooth muscle cells.

The researchers credited a seven-day, dynamic “rocking” process with maturing the cells, allowing superior physiological and contractile function versus patches that aren’t rocked.

“When two of the hCMPs were transplanted onto infarcted swine heart measurements of cardiac function, infarct size, wall stresses improved significantly with no increase in the occurrence of arrhythmogenic complications,” wrote senior study author Jianyi Zhang, MD, PhD, with UAB’s department of biomedical engineering, and colleagues.

“Changes in the expression profile of myocardial proteins indicated that hCMP transplantation partially reversed abnormalities in sarcomeric protein phosphorylation. Collectively, these observations indicate that hCMPs of clinically relevant dimensions can be successfully generated and may improve recovery from ischemic myocardial injury.”