This is a novel and exciting approach, said Duncan Stewart, M.D., professor and director of cardiology at the University of Toronto and head of cardiology at St. Michaels Hospital. Pulmonary arterial hypertension (PAH) is abnormally high blood pressure in the arteries between the heart and lungs. It is a progressive disease that can affect the arterioles and capillaries that supply blood to the lungs.

PAH reduces the hearts ability to pump blood through the lungs and gradually leads to heart failure. Today, we can achieve some improvement with drugs, but the treatment is palliative and can only delay death, Stewart said.

Restoring blood flow to the lungs with a stem cell transplant in the pulmonary vessels may hold promise as a new treatment for PAH, Stewart said.

His team used endothelial progenitor cells. Endothelial cells form a thin lining in blood vessels, providing an interface between the vessel and blood. This lining, called the endothelium, regulates a host of basic processes, such as blood clotting and blood pressure.

Our results show that endothelial progenitor cells from the bone marrow circulate in the bloodstream. We can use them to form new blood vessels or repair damaged ones, Stewart said. Stewart and co-investigator Yidan Zhao, M.D., a research associate at the University of Toronto and St. Michaels Hospital, removed vascular progenitor cells from rats bone marrow. The cells were cultured for five days, then injected into the pulmonary circulation of rats with PAH. A second group of rats with PAH received skin fibroblasts (cells), while a third group, which did not have PAH, were used as controls.

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Contact: Carole Bullock
carole.bullock@heart.org
214-706-1279
American Heart Association
10-Nov-2003