Transplanted Muscle Cells May Aid Damaged Hearts

A study in which muscle cells were transplanted from the thighs of heart patients into their damaged hearts shows evidence of skeletal muscle cell survival and differentiation into mature muscle fibers, leading perhaps to a way to repair damaged hearts without rejection. The results were presented at the 2002 Scientific Sessions of the American Heart Association in Chicago, IL (USA).

Three patients had cells from their thigh muscles injected into their heart muscle while they awaited a heart transplant, then allowed their old, damaged hearts to be examined for signs of cell growth after they received a new heart. Examination revealed that the injected cells not only survived but also began to form muscle fiber. In addition, the areas where the cells were injected showed an increase in the formation of small blood vessels. Since the muscle cells came from the patients' own bodies, none of the patients experienced an immune reaction to the transplants.

The study is based on the premise that certain kinds of cells can be expanded in culture and maintain their functional characteristics. Instead of stem cells, the study used satellite cells, which occur naturally in muscle and help repair damage by dividing and moving to injured areas. After removing cells from the quadriceps muscle, researchers treated them with enzymes to isolate the satellite cells. These were then grown in a laboratory under carefully controlled conditions to give the cells time to divide and produce 300 million cells.

One arm of the study was conducted at the University of Michigan Health System (U-M, Ann Arbor, USA) and Temple University (Chattanooga, TN, USA). This arm involved patients awaiting a heart transplant or a left ventricular assist device (LVAD). Another arm of the study, conducted at the Arizona Heart Institute (Phoenix, USA; www.azheart.com), examined how well patients tolerated different doses of transplanted muscles cells during heart bypass surgery. Indirect evidence of scar tissue regeneration was noted in these patients.

"These results give us the first indication that muscle cell transplants, even from an entirely different kind of muscle, could one day be used to help repair damaged, failing hearts without danger of rejection,” said Francis Pagani, M.D., Ph.D., head of the heart transplant program at the U-M Cardiovascular Center.




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Univ. of Michigan
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