An Extract from Bone Marrow Cells Treats Heart Failure After a Heart Attack

A new study has found than an extract derived from bone marrow cells is effective for improving cardiac function, decreasing the formation of scar tissue, and improving cardiac pumping capacity after heart attack.

Researchers at the University of California, San Francisco (UCSF; USA) conducted a study that used a novel, closed-chest, ultrasound-guided injection technique to administer three different groups of mice with either bone marrow cells, bone marrow cell extract, or saline (control group). The injections were administered at day three following an induced heart attack; the researchers then measured the left-ventricular ejection fraction (LVEF) in all groups, and found that it had fallen uniformly in each group from a level of about 57.2% to 38.4% after the heart attack.

The researchers measured LVEF again at day 28, and found that both the bone marrow cell group and the extract group had significantly smaller heart damage than the control group. LVEF improved in both the bone marrow cell and extract groups to approximately 40.6% and 39.1% respectively, compared to a further worsening in the control group, with an LVEF of only 33.2%. Both the cell and cell extract therapies resulted in the presence of more blood vessels and less cardiac cell death (apoptosis) than no therapy at all. The study also showed that heart function benefited despite the finding that few of the injected cells remained in the heart at one month after therapy. The research team is continuing to evaluate bone marrow cell and extract therapies in order to identify the proteins and factors active within the extract, and gain insight into the possible mechanisms of cardiac functional improvement. The study was published in the July 2009 issue of the Journal of Molecular Therapy.

"The best acute therapy for a heart attack remains early recognition and revascularization of the blocked artery to minimize the damage to the heart muscle,” said lead author cardiologist Yerem Yeghiazarians, M.D., director of UCSF's Translational Cardiac Stem Cell Development Program. "Although the prognosis depends on multiple factors, what we know for sure is that the sooner a heart attack gets diagnosed and cardiologists open the blocked artery, the better the long-term outcome. There are a number of ongoing stem cell-based clinical trials, and depending on further research and the outcome of these studies, we might have new therapies for the treatment of patients who suffer from a heart attack in the not-too-distant future.”

It is as yet unclear whether bone marrow cells differentiate into cardiomyocytes (cardiac muscle cells) but there is general agreement that stem cell therapy with these cells results in some level of functional improvement after a heart attack. However, the exact mechanism for this is not fully understood.

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