A new stem cell technique holds exciting potential for treating life-threatening heart failure, Canadian researchers reported today at the American Heart Association's Scientific Sessions 2000.
The approach involves taking mature stem cells from an animal's own bone marrow and injecting them directly into the heart. These cells, called marrow stromal cells, then change, or differentiate, into heart muscle cells.
So far, these experiments have only been done in animals. The Canadian team reported it had successfully created viable new heart muscle in 20 of 22 rats treated.
"Heart failure is the death of functioning heart muscle," says senior author Ray C. J. Chiu, M.D., Ph.D., professor and chairman of the division of cardiothoracic surgery at McGill University Health Centre in Montreal. "The goal of our study is to replace those dead cells with new heart muscle cells. Marrow stromal cells are extremely promising."
At birth, humans have all the heart muscle cells they will ever develop. Unlike many tissues in the body, heart muscle cells cannot replace themselves, and instead of adding new cells, the heart grows after birth by enlarging the cells it has.
"When heart cells die, they are permanently lost," Chiu says.
Heart failure stems from damage to the heart that leaves it unable to pump enough blood to meet the body's needs. It can result from a heart attack, viral infection of the muscle, or an inherited heart defect.
One way to possibly replace dead heart muscle would be the use of embryonic stem cells. These early cells can differentiate into any cell type, given the proper signal in the body, but harvesting them destroys the embryo.
The new therapy being pursued by Chiu's group might offer an alternative to using embryonic stem cells. Also, because the marrow stromal cells come from the patient, there would be no rejection of the new muscle by the immune system, thus there would be no need for expensive immunosuppr
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Contact: Carole Bullock or Maggie Francis
504-670-4000
American Heart Association
11-Nov-2000