Skeletal Muscle Hypertrophy and Cardio-Metabolic Benefits After Spinal Cord Injury

Spinal cord injury (SCI) is a devastating medical problem that affects thousands of civilian and military personnel in the United States. Spinal cord injuries (SCI) predispose individuals to impaired fitness, obesity, glucose intolerance and insulin resistance, placing them at greater risk for diabetes and coronary artery disease. These are devastating problems that occur frequently because of changes in body composition and reduced level of physical activity. Skeletal muscle wasting plays a central role in altered metabolism after SCI. Functional electrical stimulation (FES) is an effective rehabilitation tool that has been used to train the paralyzed skeletal muscles and which has shown some ability to ameliorate the deleterious effects of SCI on metabolism, particularly on insulin sensitivity. However, its ability to reverse skeletal muscle wasting is modest; most studies report limited gains in muscle mass and workload with highly variables outcomes from one study to another. This proposal was stimulated by the findings that a program of neuromuscular electrical stimulation resistance exercise prior to initiating functional electrical stimulation lower extremity cycling (FES-LEC) improves the gains in muscle mass and workload observed with FES. The specific objectives for the current proposal are to compare the impact of FES following evoking skeletal muscle hypertrophy of the lower extremity versus initiating FES cycling without introducing the hypertrophy effects on insulin sensitivity, control of blood sugar levels, oxygen uptake and amounts of muscle tissue and fat deposition. These studies could potentially have significant effects on thousands of people that will experience an SCI in the future as well as those living with SCI where prolonged paralysis is a major quality of life issue.

There is a major need to investigate the mechanisms lead to maximize the benefits of FES applications and to understand cellular or molecular events that are associated with muscle hypertrophy and lead to promoting metabolic health after SCI. The designed study will provide a greater understanding regarding utilization of energy sources (like fats and sugars) in muscle