Pretreatment with a clinically appropriate dose of the antibiotic rapamycin induces a protective effect in an animal model against myocardial infarction related to ischemia or reperfusion injury, according to an article in the July issue of the Journal of Molecular and Cellular Cardiology.

“Rapamycin may one day be beneficial as a potential therapeutic strategy to limit cell death caused by ischemia or reperfusion injury, and possibly long-term prevention of ventricular remodeling ? the changes in size, shape and function that may occur to the left ventricle of the heart,” said Rakesh C. Kukreja, PhD, lead author of the study.

Researchers believe rapamycin enables myocardial cells to maintain adequate levels of ATP through the opening of the mitochondrial KATP channel. Rapamycin blocks protein synthesis by inhibiting the mammalian target of rapamycin (mTOR), an essential component in the pathway of cell cycle progression. The drug has been found to be important in transplant medicine, especially in kidney or heart transplantation.

Additionally, Kukreja said that because of the antibiotic’s antigrowth properties, rapamycin effectively reduces coronary restenosis. In coronary angioplasty, stents coated with rapamycin are implanted to reduce the risk of restenosis.
“A significant clinical question will be whether or not rapamycin-coated stents can be utilized in patients to favorably affect damaged heart muscle beyond the blockage causing a heart attack,” said George W. Vetrovec, MD, a co-author of the study.

For the last several years, Kukreja and colleagues have studied a class of erectile dysfunction drugs known as phosphodiesterase-5 inhibitors as part of ongoing research into heart protection. The team first investigated sildenafil and vardenafil and found that both compounds showed cardioprotective effects during experimental myocardial infarctions in animal models.