Increased collagen content in insulin-resistant skeletal muscle
Rachele Berria1, Lishan Wang, Dawn K Richardson
1Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA.
American Journal of Physiology. Endocrinology and Metabolism
|October 27, 2005
Summary
Insulin resistance in skeletal muscle is linked to increased collagen content. This study found higher collagen in obese and type 2 diabetic individuals, suggesting extracellular matrix changes are common in insulin resistance.
Area of Science:
- Muscle physiology
- Metabolic disorders
- Extracellular matrix biology
Background:
- Lipid oversupply and underutilization are linked to skeletal muscle insulin resistance.
- Mitochondrial dysfunction is a potential mechanism, and extracellular matrix changes may impact mitochondrial function.
Purpose of the Study:
- To investigate if insulin-resistant, nondiabetic obese subjects and type 2 diabetes mellitus patients exhibit increased muscle collagen content.
- To explore the relationship between extracellular matrix composition and insulin resistance.
Main Methods:
- Assessed muscle collagen abundance via total hydroxyproline content in lean controls, obese nondiabetics, and type 2 diabetics.
- Utilized immunofluorescence staining to identify collagen types in muscle biopsies.
Main Results:
- Obese and type 2 diabetic subjects showed significantly reduced muscle glucose uptake and impaired insulin signaling.
- Collagen abundance was significantly increased in muscle from both obese nondiabetic and type 2 diabetic individuals compared to lean controls.
- Immunofluorescence confirmed increased abundance of type I and type III collagen in insulin-resistant muscle.
Conclusions:
- Increased collagen content is a characteristic feature of insulin-resistant muscle.
- Changes in extracellular matrix composition are a general hallmark of insulin resistance, independent of hyperglycemia.
- These findings highlight the role of the extracellular matrix in metabolic dysfunction.
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