What This Means
People with chronic kidney disease often become less active and develop weak, damaged muscles, including scarring (fibrosis), poorer blood supply, and impaired repair. This study looked at whether a 12-week home-based exercise program, monitored by video, could change the structure of muscle in people with stage 3-5 kidney disease. Twenty-five participants were randomized (19 to exercise, 6 to usual care), and muscle biopsies from the thigh were taken before and after.
The exercise program, which mixed high-intensity intervals, power walking, and strength training, did not change muscle fiber size, fiber type, stem-like satellite cell numbers, or measures of scarring such as collagen and extracellular matrix. However, it increased the density of small blood vessels (capillaries) in the muscle, improved the muscle's ability to use oxygen measured in the body, and lowered the number of fibroadipogenic progenitors, cells that can contribute to scarring and fat buildup. Walking distance showed a trend toward improvement.
This research suggests that muscle in people with CKD can still adapt to exercise done at home, particularly in ways related to endurance and blood supply. The reduction in fibroadipogenic progenitors may hint at less scarring over time, though this was not shown directly. The study was small, with only 6 usual-care participants, so the findings should be viewed cautiously.