Rebuilding a damaged heart

Dr. Joshua Hare and his colleagues at the Johns Hopkins University School of Medicine and its Heart Institute in Baltimore are hoping that dying hearts can be made new. Because of recent research, many doctors believe the heart has regenerative capacity.

Since March 2005, Dr. Hare, professor of medicine at the school and institute, has been enrolling heart attack patients in a trial to see if mesenchymal stem cells from bone marrow can regenerate a damaged heart. He previously performed trials with pig hearts.

“The primary purpose of the study is to access the safety of the procedure,” Dr. Hare says. “We’re thrilled with the progress we’ve made. We should finish in 2006.”

Five years ago, most doctors never would have considered using stem cell therapy to help heart attack victims, but today, many experts say the procedure could redefine the field of cardiology. Though much research is still needed, cardiologists are excited about the possibilities it could provide.

After people have a heart attack, if they are enrolled in Dr. Hare’s study, they are infused with mesenchymal stem cells from bone marrow and followed for six months. He won’t know the results until six months after the last of the 52 patients is enrolled.

The cells, which are grown in culture, are prepared with good quality control, he says. They are not harvested from the patients, but from an unrelated donor and prepared in advance.

Making a new therapy available to the public is a difficult and heavily regulated process, Dr. Hare says.

Though the study is approved by the U.S. Food and Drug Administration, many other trials will have to take place before the new therapy is approved, he says. Johns Hopkins Hospital recently received a grant from the National Institutes of Health to be a specialized center for cell therapy.

“It’s frustrating for certain patients,” Dr. Hare says. “They feel they have run out of options. Certain people leave the country for the therapy. It’s something we are concerned about because we’re not sure those people are getting a safe or proven therapy.”

After the studies focusing on heart attack patients are completed, Dr. Hare will run trials concerning stem cell treatment for congestive heart failure in pigs and then in humans.

The effectiveness of taking stem cell cultures from patients’ own hearts also is being studied, says Dr. Eduardo Marban, professor and chief of the cardiology

division at the medical school and the institute. Trials are being performed in pigs. By the end of 2006, research will begin in humans.

“The big race is on to find the best kind of stem cell,” Dr. Marban says. “We can take human cells from the heart and put them in mice, and it improves the hearts of mice that had heart attacks.”

Significant regrowth in the hearts of mice takes three weeks, he says. He estimates that it may take two to four months to have the same effect in human hearts.

In the future, trials probably will be performed combining and comparing mesenchymal stem cells from bone marrow and cardiac stem cells, he says.

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