Injections into heart restore blood flow in small study
Injecting bone marrow cells into the heart's muscular wall restored blood flow to hearts with blocked arteries for which conventional treatments had proven ineffective, Dutch physicians have reported.
"I think this is very good news for patients who are at the end of the line and have no options left," said Dr. Douwe E. Atsma, an interventional cardiologist at Leiden University Medical Center and an author of the study, which appears in the May 20 issue of the Journal of the American Medical Association.
The 50 people in the study, 43 of them men, were experiencing angina, or severe chest pain, because of blockages in their heart arteries. All had undergone several artery-opening procedures, such as angioplasty or bypass surgery, to restore blood flow, but such measures would no longer help them, Atsma said.
Half of the participants received injections of cells taken from their own bone marrow, and the others received inactive cell injections. After three months, the responses were varied, with some participants reporting complete relief and others with partial benefits.
"The most important thing is that the amount of ischemia [artery blockage] was halved" in those given the marrow cells, Atsma said. "The amount of tissue with ischemia was reduced, heart function improved significantly in a small way and their grades of quality of life were higher."
Two earlier and smaller trials of bone marrow cell therapy for heart disease had produced conflicting results, Atsma said. "We are the largest trial to date and the first to demonstrate a decrease in ischemia," he said.
The results were so good, Atsma said, that the participants who had gotten the dummy injections have since been given bone marrow cell therapy, and "we now consider it an option for patients in the same condition," he said.
The study excluded people with heart failure, which occurs when the heart muscle has become too weak to pump blood properly. But Atsma said that a trial of bone marrow cell therapy for people who have blocked arteries as well as heart failure is planned.
The bone marrow cell injections help restore blood flow by promoting the creation of new blood vessels, Atsma said, but it's not clear how this happens. "It could be that the cells that are injected become part of the vasculature, the blood vessels," he said. "Even better, the injected cells may secrete proteins that stimulate angiogenesis, formation of blood vessels. Or it might be a combination of those two things."
Whatever the reason for the benefit of bone marrow cell therapy, "we are fairly enthusiastic, considering that these patients had no alternative," Atsma said. "They had all the surgery and angioplasty they could have."
Dr. Amit Patel, director of cardiovascular regenerative medicine at the University of Utah, described the finding as "definitely a step forward in the treatment of chronic angina." But he had some cautionary comments.
It was a small study, with just 50 participants, he said, adding that "to make it a more reproducible therapy, you would have to do at least a couple of hundred patients."
Also, the follow-up period was relatively short, at three months, he noted. "Something positive happened, but you would have to follow these patients further to see how long it would last," Patel said. Future studies to determine whether there would be an overall improvement in heart function would also be welcome, he said.
Doris Taylor, director of the University of Minnesota Center for Cardiovascular Repair, also had qualified praise for the results.
"The good news is that it is more mechanistic in that it gives some insights into perfusion," she said. "It reinforces the evidence that bone marrow cells are safe and effective. It also reinforces the prevailing wisdom that it is not a home run. The results are positive, but it is not the panacea we hoped it would be."
To further the baseball analogy, Taylor said that "for the people who feel better, I would consider it a double."
More studies are needed to learn about the value of cell therapy "across the complete spectrum of cardiovascular disease," she said. "We need to understand what we need to do differently. I hope these data provoke that conversation."
Source: Forbes Magazine 19 May 2009