(齐康网) ANAHEIM, California (Reuters Health) - A series of studies, presented here Tuesday at the American Heart Association’s 2001 Scientific Sessions, show that the transplantation of cells taken from peripheral muscles and injected into infarcted areas of the myocardium are not only incorporated but begin to take on some characteristics of cardiomyocytes. Most importantly, the cell transplants improve contractility in the infarcted areas.
Dr. Phillippe Menasche from H魀ital Bichat in Paris presented long-term results of animal studies and phase I results of the first 10 patients with severe heart failure to receive autologous skeletal myoblast transplantation at the time of bypass surgery.
At 1 year, animals with myocardial infarctions who received skeletal myoblast transplants continued to show improved myocardial contractility and greatly increased ejection fractions, while control animals deteriorated during follow-up. Histologic findings revealed that the transplanted cells contained skeletal muscle myocine, as expected, and some cardiac muscle myocine. "Some [cellular] adaptation occurred. It altered a little bit of the phenotype [of the cells]," he reported.
Dr. Menasche also reported the status of 10 patients who received autologous skeletal myocytes taken from thigh muscle that were injected in multiple sites of akinetic infarcted areas during bypass surgery involving different areas of the heart.
The investigators expanded the skeletal myocytes ex vivo over a 2-to-3 week period before transplantation. There was one early postoperative death and some incidence of arrhythmias. Dr. Menasche said that arrhythmias are a "potential but transient" adverse effect of myocyte transplantation, but he noted that these patients are already at high risk of arrhythmias.1621
At followup, 11 of 18 muscle segments are contractile and show signs of systolic thickening. The first patient, who received transplantation 1 year ago, continues to do well, Dr. Menasche reported. There has been a 13% increase in ejection fraction in the patients.
Although live cells are transplanted into infarcted areas, Dr. Menasche told Reuters Health that these areas "are never completely avascular...there are some residual capillaries, and that could be enough to keep the cells alive. Also, myocytes are remarkably resistant to ischemia." He added that about 90% of the transplanted cells do die.
Dr. Patrick W. Serrys of the Thorax Center in Rotterdam described the case of a woman with class III/IV heart failure who received skeletal myocytes delivered via catheter directly to infarcted tissue, thereby avoiding an open heart procedure.
At 3-month follow-up, the woman’s condition has improved to class I heart failure and she has an improved ejection fraction. Her activity level has improved so much that she is once again considering hip surgery.
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