The effect of replicated intermittent fasting on type 2 diabetic and non-diseased human skeletal muscle myoblasts

Fasting and intermittent fasting have become new fad diets that put the aging and diabetic populations at risk for muscle atrophy. Type 2 diabetes is associated with insufficient insulin secretion and affects millions of people globally. With doctors prescribing fasting diets to patients with the intention of fat loss, they could potentially be putting them at risk for enhanced muscle wasting. PURPOSE: The purpose of this study was to examine the effects of nutrient stress on human skeletal muscle metabolism, with an emphasis on oxidative stress and atrophy markers in healthy and diabetic cell models. METHODS: Human skeletal muscle myoblast cells (HSMM) and diabetic human skeletal muscle myoblast cells (D-HSMM) were cultured in a 37° C and 5% CO2 incubator. At 80-90% confluency,10 cells were transferred into four 24 well plates and were incubated for 48h with standard culture media. The cells were then incubated for 12 or 24 hours with media containing varying serum concentrations: 5%, 10%, and 15%. The media contained either fetal bovine serum (FBS) or pooled human serum (HS) from healthy and diabetic patients (Doctors Regional, Corpus Christi TX). Following the 24 hours, cell viability and density were determined, and sandwich enzyme linked immunosorbent assay kits were performed to measure the amount of SOD1, Atrogin-1, and TNF-α in serum. TaqMan gene array plates were used to qualitatively assess gene expression in several atrophy biomarkers through RT-PCR reaction assessed through Quant Studio 3. RESULTS: Gene expression revealed 1.187-fold change in Myostatin and a 1.378-fold change in AKT2 in 15% D-HSMM model. A 0.081-fold change was seen in Atrogin-1 in the 5% D-HSMM model. HS models in HSMM and D-HSMM cells show significant impact of treatment concentration on SOD1 expression (p<0.0001). The TNF-α ELISA suggests that time has a significant effect on TNF-α vi concentration for HSMM cells plated with FBS (p=0.0211). Treatment concentration in HSMM HS model revealed a significant effect of treatment concentration (p=0.0116). An Atrogin-1 ELISA revealed virtually no presence in serum. CONCLUSION: The results indicate that the different nutrient states have deleterious effects on muscle cells through oxidative stress and inflammation. Upregulation in atrophy biomarkers also indicate instances of muscle wasting. The promotion of nutrient deprivation or fasting should be done with caution to avoid harmful outcomes in healthy and disease states.