REMARKS AND FUTURE DIRECTION
Loss of muscle mass involves a number of underlying mechanisms including intrinsic changes in the muscle and central nervous system, humoral, and lifestyle factors. However, nutrition is the key regulator of muscle maintenance through its numerous biological actions on protein synthesis machinery. Many data demonstrate that nutritional means to counter sarcopenia exist. These strategies aim at improving amino acid availability since postprandial elevation of plasma AA is the main determinant of muscle anabolism. Other metabolic aspects can modulate sensitivity of skeletal muscle to nutrients, like the quality and the pattern of daily protein intakes rather than simply increasing the amount of proteins which should be cautiously used in an aged population with a potentially reduced kidney function. Inactivity also induces anabolic resistance and regular exercise could reverse this phenomenon. The combination of specific nutritional and physical activity programs may have a significant effect on muscle protein balance in young subjects. This strategy has to be tested in older people. Furthermore, the possibility of therapeutic approach to enhance protein synthesis and to limit sarcopenia has been emphasized by studies in the care management of heart failure [104], hypertension [105, 106] or COPD [107]. Other approaches using angiotensin‐converting enzyme inhibitors have resulted in a reduction of strength and walking speed decline in comparison with other antihypertensive agents [108]. This evidence of pharmacological approaches is able to help to reduce age‐related weakness and dependence. So, interventional strategies using nutritional advices, drugs, and/or exercise need to be studied in large groups of subjects before being applied to the general public. The ultimate objective of such investigations is to restore mobility and to limit physical dependence of older people in order to improve their quality of life.
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