Maintaining and restoring mobility in middle and old age: the importance of the soft tissues

For many older individuals, impairment of musculoskeletal function, especially weakness, stiffness, and pain, cause progressive disability, thereby limiting mobility and decreasing the quality of life. With advancing age, musculoskeletal soft tissue function declines, susceptibility to degenerative diseases and injuries increases, and the ability to recover from disease or injury declines; these changes increase the probability of impairment (Fig. 1). However, the function of individual cells, tissues, or organ systems may remain stable or even improve temporarily with age, and a number of interventions have the potential to maintain or improve musculoskeletal function. Age-related changes in cells, tissues, and musculoskeletal function are not necessarily unidirectional or uniform among individuals, organ systems, tissues, or cells, nor are they necessarily irreversible. Surgical procedures can restore mobility for many patients with age-related musculoskeletal injuries or degenerative diseases. Regular resistance and range-of-motion exercises can decrease the age-related loss of strength and help maintain or restore flexibility. However, exercise programs can also cause injury. Older individuals should have a careful medical evaluation before starting an exercise program, and the program should be selected based on this evaluation. This is especially important for individuals with systemic illness and for individuals at greater risk of musculoskeletal injury, including people with previous joint injuries, obesity, osteoarthritis, joint deformity, weakness, or restricted joint motion. Trophic hormone replacement or supplementation may also modify age-related changes in the soft tissues, including loss of strength, but these hormones have adverse effects. Systemic or local use of growth factors and cell transplantation after expanding the population of mesenchymal stem cells in culture could improve healing in older people. Other potential methods of slowing or reversing age-related deterioration of the soft tissues include inhibition of posttranslational modification of matrix proteins and alteration of the activity of selected transcription factors. In particular, better understanding of the role of transcription factors in cell sequence may make it possible to devise methods of delaying or reversing age-related loss of cell proliferative and synthetic capacity.