Pharmacologic Options for the Treatment of Sarcopenia.

Sarcopenia is now clinically defined as a loss of muscle mass coupled with functional deterioration (either walking speed or distance or grip strength). Based on the FRAX studies suggesting that the questions without bone mineral density can be used to screen for osteoporosis, there is now a valid simple questionnaire to screen for sarcopenia, i.e., the SARC-F. Numerous factors have been implicated in the pathophysiology of sarcopenia. These include genetic factors, mitochondrial defects, decreased anabolic hormones (e.g., testosterone, vitamin D, growth hormone and insulin growth hormone-1), inflammatory cytokine excess, insulin resistance, decreased protein intake and activity, poor blood flow to muscle and deficiency of growth derived factor-11. Over the last decade, there has been a remarkable increase in our understanding of the molecular biology of muscle, resulting in a marked increase in potential future targets for the treatment of sarcopenia. At present, resistance exercise, protein supplementation, and vitamin D have been established as the basic treatment of sarcopenia. High-dose testosterone increases muscle power and function, but has a number of potentially limiting side effects. Other drugs in clinical development include selective androgen receptor molecules, ghrelin agonists, myostatin antibodies, activin IIR antagonists, angiotensin converting enzyme inhibitors, beta antagonists, and fast skeletal muscle troponin activators. As sarcopenia is a major predictor of frailty, hip fracture, disability, and mortality in older persons, the development of drugs to treat it is eagerly awaited.