Important research out of Cedars-Sinai Heart Institute shows promise for heart muscle damage caused by Duchenne Muscular Dystrophy. Scientists studying the muscle wasting disease report that the injection of cardiac stem cells can potentially reverse muscle damage to the heart, leading to longer life expectancy in patients who suffer from this disease.
At the November 2014 American Heart Association Scientific Sessions in Chicago, the study findings were revealed at Breaking Basic Science presentation. Laboratory mice with Duchenne Muscular Dystrophy were infused with cardiac stem cells. These mice showed significant and steady improvement in heart function as well as increased exercise capacity.
Duchenne muscular dystrophy, which affects 1 in 3,600 boys, is a neuromuscular disease caused by a shortage of a protein called dystrophin, leading to progressive muscle weakness. Most Duchenne patients lose their ability to walk by age 12. Average life expectancy is about 25. The cause of death often is heart failure because the dystrophin deficiency leads to cardiomyopathy, a weakness of the heart muscle, which makes the heart less able to pump blood and maintain a regular rhythm. The study conducted by the Cedars-Sinai Heart Institute is the first of it's kind to address heart muscle damage in Duchenne patients.
In the study, 78 lab mice were injected with cardiac stem cells. Over the next three months, the lab mice demonstrated improved pumping ability and exercise capacity in addition to a reduction in heart inflammation. The researchers also discovered that the stem cells work indirectly, by secreting tiny fat droplets called exosomes. The exosomes, when purified and administered alone, reproduce the key benefits of the cardiac stem cells.
"Most research into treatments for Duchenne muscular dystrophy patients has focused on the skeletal muscle aspects of the disease, but more often than not, the cause of death has been the heart failure that affects Duchenne patients," said Eduardo Marbán, MD, PhD, director of the Cedars-Sinai Heart Institute and study leader. "Currently, there is no treatment to address the loss of functional heart muscle in these patients."
Dr. Marbán has pioneered cardiac stem cell research before this latest study. In 2009, Marbán and his team were the first researchers to successfully use a patient's own heart tissue to grow specific cardiac stem cells. These cells were then injected back into the patient's heart to see if muscle damage from a previous myocardial infarction could be repaired. The results of that study were published in 2012 in The Lancet and showed that patients who received the experimental cardiac stem cells had a significant decrease in the scar tissue left behind on the heart muscle.
Earlier this year the Heart Institute's team of researchers began a new study of heart attack patients. In this project, called ALLSTAR, allogeneic stem cells were infused into patients to see if damaged heart muscle could be regenerated. The stem cells used were from donor quality hearts. In addition, the Heart Institute has opened the nation's first Regenerative Medicine Clinic, designed to match patients suffering from various cardiac and vascular diseases to current stem cell studies being conducted at Cedars-Sinai and other institutions.