Study Shows Way To Grow New Blood Vessels In The Heart

Scientists here are seeking new methods for patients to grow blood vessels in the heart to replace the ones they've lost in a heart attack.

Nicanor I. Moldovan, assistant professor at Ohio State's new Heart and Lung Institute and Biomedical Engineering Center, said he and his colleagues' most recent work is a step forward to reach that goal. The scientists reported their initial progress in a recent issue of the journal Circulation Research.

Moldovan explained that during a heart attack, blockage in coronary arteries leaves a portion of the victim's heart tissue without oxygen, a condition called ischemia. When this happens, part of the heart tissue begins to die -- an event signaled by severe chest pain.

In his early work, Moldovan discovered that in a mouse model of cardiac ischemia, blood-derived cells called monocytes penetrate this damaged heart tissue, leaving behind a network of tunnels in the tissue.

Monocytes, the largest blood cells, normally circulate through the body to capture and ingest infectious agents such as bacteria. Monocytes also penetrate enflamed body tissue to help defend against infections.

For this Circulation Research study, scientists tested the hypothesis that new blood vessels may grow in tunnels created by monocytes. They took mouse hearts containing monocyte-caused tunnels and transplanted them into healthy mice.

Five days later, the researchers found evidence in the transplanted hearts that new blood vessels may have been about to grow: stem cells -- cells that normally precede blood vessel growth -- had begun to colonize the tunnels.

The findings point the way to a possible new therapy for heart attack victims that will help them regenerate blood vessels and keep damaged tissue alive, Moldovan said. "If we could create similar tunnels in heart tissue -- with or without monocytes' contribution -- we might be able to stimulate capillary formation," he said.

He did admit, however, that this project is in its infancy. He and his colleagues will have to overcome many obstacles to find a practical way to grow functioning blood vessels, based on this new principle, he said. The question of whether the tunnels themselves improve heart function remains as well.

Moldovan and his colleagues are also exploring means for growing blood vessels outside the body and then implanting them in the tunnels in the heart tissue.

Moldovan's colleagues included Pascal Goldschmidt, chief of cardiology at Duke University; Jan Parker-Thornburg, a research scientist, and Pappachan Kolattukudy, professor of molecular and cellular biology, both from Ohio State's Neurobiotechnology Center; and Steven Shapiro, professor of pediatrics at Washington University in St. Louis School of Medicine. This work was supported by grants from the National Institutes of Health, the American Heart Association, and the Scleroderma Research Foundation.