Novel therapies for sarcopenia: ameliorating age-related changes in skeletal muscle

Among the most serious consequences of ageing are its effects on skeletal muscle structure and function. Ageing is associated with a progressive loss of muscle mass (sarcopenia) motor function, a slowing of muscle movements and a decline in muscle strength. These age-related changes in muscle properties contribute to the gradual loss of functional independence and the increased incidence of fall-related injuries in the elderly. Progressive muscle fibre denervation, the loss of motor units and subsequent motor unit remodelling have been implicated as mechanisms responsible for these deleterious effects of ageing on skeletal muscle, especially the loss of force and power output. However, the age-related reduction in the speed of contraction has been reported to occur before the onset of severe muscle wasting, indicating that age-related changes intrinsic to skeletal muscle fibres cannot be excluded. Even in the absence of disease, muscles atrophy and become functionally weaker with age. From a public health perspective, sarcopenia has widespread clinical implications. Diminished muscle mass and functional strength with age increases the risk of injury from sudden falls and increases the dependence on the frail elderly for assistance in accomplishing even the most basic tasks required for independent living, including the maintenance of personal hygiene, feeding and recreational pursuits, leading to an inability to perform even simple activities required for daily living. Research into ageing and muscle function is of increasing importance to the community as the ageing population continues to escalate. It is generally agreed that such age-related changes in skeletal muscle structure and function are inevitable, although debate exists as to whether these intrinsic changes are immutable or reversible. Clearly, there is a profound need for therapeutic intervention strategies that aim to slow the effects of ageing on muscle function and/or restore muscle size and strength in the frail elderly so as to improve or maintain their quality of life. This review examines recent (1998 - 2001) patents on novel strategies for ameliorating the effects of ageing on muscle structure and function.