Blood Flow, Muscle Regeneration and Sarcopenia

Due to the rapid aging of the population, sarcopenia is among the greatest challenges facing the health care system over the next quarter century. This age-related loss of skeletal muscle mass and strength directly contributes to the incidence of functional disability, thereby reducing independence and quality of life for the elderly. Despite increasing efforts to combat sarcopenia, its etiology remains incompletely described. Subsequently, limited progress has been made in developing comprehensive preventative and therapeutic strategies to combat the problem. A decreased ability to regenerate skeletal muscle fibers through the donation of skeletal muscle stem cells (satellite cells) is thought to contribute to sarcopenia. However, the upstream physiological mediators that regulate this impairment are poorly delineated. Reduced muscle blood flow in advanced age appears to be a significant factor in reducing skeletal muscle regenerative capacity, but few data exist to confirm this hypothesis. Thus to test this hypothesis we aim to conduct a translational pilot trial which examines regeneration in both young and old adults. Furthermore, we aim to determine if muscle blood flow and satellite cell number are associated with muscle function. The central hypothesis of this proposal is that age-related declines in skeletal muscle angiogenesis and perfusion are significant causal factors in age-related losses of skeletal muscle mass. The specific aims and hypotheses of the project are as follows: