Increased susceptibility to oxidative damage in post-diabetic human myotubes

Area of Science:

• Metabolic research
• Cellular biology
• Diabetes research

Background:

• Obesity is a significant risk factor for type 2 diabetes.
• While weight loss can reverse clinical type 2 diabetes symptoms, the persistence of skeletal muscle oxidative stress is unknown.
• Understanding muscle cell response to metabolic challenges is crucial for predicting diabetes risk.

Purpose of the Study:

• To investigate if chronic high glucose and insulin exposure re-elicits impaired metabolism in primary myotubes from individuals with a history of type 2 diabetes.
• To determine if weight loss eliminates skeletal muscle oxidative stress associated with type 2 diabetes.

Main Methods:

• Obese participants with and without type 2 diabetes underwent weight loss.
• Satellite cells were isolated from muscle biopsies and differentiated.
• Cells were exposed to low or high glucose and insulin conditions (HGI).

Main Results:

• Myotubes from individuals without type 2 diabetes history increased mitochondrial content and oxidative capacity under HGI.
• Myotubes from individuals with type 2 diabetes history showed absent increases in oxidative capacity and increased oxidative damage under HGI.
• Cells from type 2 diabetes history group failed to decrease mitochondrial membrane potential in response to HGI.

Conclusions:

• Primary myotubes from individuals with a history of type 2 diabetes cannot adapt to hyperglycaemic-hyperinsulinaemic challenges.
• Impaired mitochondrial biogenesis and oxidative stress management define a muscle phenotype at risk for obesity-associated type 2 diabetes.