Heart Damage Prevented (IMAGE) Michigan Medicine - University of Michigan Caption Heart muscle cells in untreated rats bred to develop heart failure show signs of disease. Right: Heart muscle cells remain healthy in rats treated with calcitriol, the hormone that Vitamin D becomes in the body. Credit University of Michigan Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.