Exercise and inflammatory gene expression after hip fracture
Hip fractures represent a significant cause of mortality and morbidity among the elderly. Profound weakness and atrophy of the hip musculature often follows fractures and can lead to functional decline. Physiologically, this weakness is thought to be mediated through increased expression of inflammatory and ceramide biosynthesis genes via the Toll-like receptor pathway (TLP). Rehabilitation programs post hip fracture have been shown to be effective in improving functionality and quality of life. however, there have been few studies that investigate the physiological effect of exercise programs on genetic expression of inflammatory markers in skeletal muscle post hip fracture.
In this study, quadriceps biopsies were taken before and after a 3-month exercise program in 7 seniors following a traumatic hip fracture and compared with age matched, non-fractured peers. The exercise program was supervised by a physiotherapist and consisted of high intensity resistance training, gait re-education, group Tai Chi and balance/ mobility exercises. Various markers related to inflammatory and ceramide biosynthesis gene expression levels, associated with TLP, were assessed via the biopsies.
Post exercise program, the fracture group showed significantly decreased expression of several inflammatory genes, although several genetic markers remained elevated above the level of that seen in the control group. There was also a significant increase in the cross-sectional area and quality of the muscle.
These data indicate that a 3-month program of regular supervised exercise may lead to reduced expression of inflammatory genes, and therefore reduced atrophy and weakness in hip musculature. As such, therapists are well placed to educate patients and other health care professionals on the importance of physiotherapy, as well as the physiological bases for muscle weakness post hip fracture.
> From: McKenzie et al., J Appl Physiol 122 (2017) 68-75. All rights reserved to the American Physiological Society. Click here for the online summary.