Fatigue Resistant Muscle by Cell Transplantation and Electrical Conditioning

Congestive heart failure refractory to medical therapy can be managed with cardiac transplantation or artificial heart. Due to the scarcity of donor organs and unsatisfactory longterm outcomes of mechanical devices, skeletal muscle has been used to augment circulatory function. Dynamic cardiomyoplasty, skeletal muscle ventricle, aortomyoplasty, and muscle powered assist devices all require the fatigue resistant muscle to support the failing heart. However, muscle transformation by chronic electric stimulation commonly suffers fibrosis, atrophy, fatty degeneration, and diminished power. Masticatory muscles appear to be highly specialized in mammals and exhibit superior fatigue resistance. Satellite cells isolated from mastication muscles retain their phenotypic characteristics after transplanted into other muscles. Muscle biopsy (~1 g) from canine masseter muscle was used for satellite cell isolation and in vitro proliferation of the myogenic cells. Latissimus dorsi muscles from 12 dogs were randomly assigned into three groups of treatments: 1) control, 2) electrical conditioning, 3) cell transplant + electrical conditioning. After two weeks of vascular delay and eight weeks of conditioning, at the end of fatigue test the power outputs were 0.21±0.02, 0.48±0.07, and 1.30±0.09 watts with the muscle mass of 162±14, 119±18, and 164±15 g for the control, electrical conditioning, and cell transplant + electrical conditioning groups, respectively. Transplantation of autologous satellite cells from jaw closing muscle and chronic electrical stimulation produced skeletal muscle of highly fatigue resistance with preserved mass and power output. This type of muscle could be used for circulatory support or as a permanent power source for assist devices.