In This Issue of Diabetes

摘要

Muscle stem cells, or satellite cells, are likely impaired in type 1 diabetes and as such may contribute to the skeletal muscle atrophy that is often observed as a complication of the disease. This is according to the outcome of a study by D'Souza et al. (p. 3053) in which they investigated the condition of satellite cells in mice with type 1 diabetes and, significantly, human muscle biopsy samples obtained from young adult donors with the disease. According to the authors, mice that naturally develop type 1 diabetes at 4 weeks (Akita mice) had reduced endurance and increased muscle damage following exercise in comparison to controls. An examination of satellite cells in the two groups revealed a more general failure to generate new muscle cells (myogenesis) in the mice with diabetes, and consequently satellite cell content was also reduced. Additional markers of myogenesis were also reduced in the diabetic mice. To then understand the potential pathways involved, the authors investigated Notch signaling on the basis of its well-established role in myogenesis. Persistent activation of the pathway was observed in satellite cells of the diabetic mice, which could also be reversed with a Notch inhibitor. On that basis they suggest such activation impairs satellite cell functionality in diabetic muscle. However, perhaps most significantly, most of these observations were also seen in human type 1 diabetes skeletal muscle samples, lending more support to the observations seen in mice. Commenting more widely on the study, author Thomas J. Hawke told Diabetes: "These impairments in the muscle stem cell population were profound and, more worrisome, were observed in young adulthood. Given the importance of skeletal muscle to our physical abilities and our metabolic health, deficiencies in the satellite cell population would mean a significant reduction in the ability of diabetic muscles to utilize glucose and lipids from the blood and to grow and repair following exercise. Clearly our next steps are about uncovering strategies to reverse these defects."