Phenotypic Characterization of Insulin-Resistant and Insulin-Sensitive Obesity

Area of Science:

• Metabolic research
• Obesity studies
• Endocrinology

Background:

• Obesity and insulin resistance frequently coexist.
• However, some individuals with obesity maintain insulin sensitivity.
• Understanding this variability is crucial for metabolic health.

Purpose of the Study:

• To investigate phenotypic and metabolic factors associated with insulin sensitivity in muscle and liver among obese individuals.
• To identify protective factors against insulin resistance in obesity.

Main Methods:

• Sixty-four non-diabetic obese adults underwent hyperinsulinemic-euglycemic clamps.
• Muscle and liver insulin sensitivity were assessed using glucose infusion rate and endogenous glucose production suppression.
• Clinical parameters, including body composition and fat distribution (visceral, subcutaneous, liver, pancreatic), were measured.

Main Results:

• Individuals with muscle insulin sensitivity (Musclesen) had lower glycated hemoglobin and blood pressure, despite similar body mass index and total fat compared to insulin-resistant counterparts (Muscleres).
• Musclesen also exhibited lower visceral and liver fat.
• Insulin sensitivity in either muscle or liver conferred protection against adverse metabolic features.
• Factors like HDL-cholesterol, 1-hour glucose, systolic BP, and triglycerides explained 54% of the variance in muscle insulin sensitivity.

Conclusions:

• Obese individuals with insulin sensitivity in muscle and/or liver display favorable metabolic profiles, including reduced blood pressure and adiposity.
• This research highlights specific factors contributing to insulin sensitivity in the context of obesity.
• Maintaining insulin sensitivity is associated with better overall metabolic health in obese populations.