TY - JOUR
T1 - Increased collagen content in insulin-resistant skeletal muscle
AU - Berria, Rachele
AU - Wang, Lishan
AU - Richardson, Dawn K.
AU - Finlayson, Jean
AU - Belfort, Renata
AU - Pratipanawatr, Thongchai
AU - De Filippis, Elena A.
AU - Kashyap, Sangeeta
AU - Mandarino, Lawrence J.
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2006/3
Y1 - 2006/3
N2 - Oversupply and underutilization of lipid fuels are widely recognized to be strongly associated with insulin resistance in skeletal muscle. Recent attention has focused on the mechanisms underlying this effect, and defects in mitochondrial function have emerged as a potential player in this scheme. Because evidence indicates that lipid oversupply can produce abnormalities in extracellular matrix composition and matrix changes can affect the function of mitochondria, the present study was undertaken to determine whether muscle from insulin-resistant, nondiabetic obese subjects and patients with type 2 diabetes mellitus had increased collagen content. Compared with lean control subjects, obese and type 2 diabetic subjects had reduced muscle glucose uptake (P < 0.01) and decreased insulin stimulation of tyrosine phosphorylation of insulin receptor substrate-1 and its ability to associate with phosphatidylinositol 3-kinase (P < 0.01 and P < 0.05). Because it was assayed by total hydroxyproline content, collagen abundance was increased in muscle from not only type 2 diabetic patients but also nondiabetic obese subjects (0.26 ± 0.05, 0.57 ± 0.18, and 0.67 ± 0.20 μg/mg muscle wet wt, lean controls, obese nondiabetics, and type 2 diabetics, respectively), indicating that hyperglycemia itself could not be responsible for this effect. Immunofluorescence staining of muscle biopsies indicated that there was increased abundance of types I and III collagen. We conclude that changes in the composition of the extracellular matrix are a general characteristic of insulin-resistant muscle.
AB - Oversupply and underutilization of lipid fuels are widely recognized to be strongly associated with insulin resistance in skeletal muscle. Recent attention has focused on the mechanisms underlying this effect, and defects in mitochondrial function have emerged as a potential player in this scheme. Because evidence indicates that lipid oversupply can produce abnormalities in extracellular matrix composition and matrix changes can affect the function of mitochondria, the present study was undertaken to determine whether muscle from insulin-resistant, nondiabetic obese subjects and patients with type 2 diabetes mellitus had increased collagen content. Compared with lean control subjects, obese and type 2 diabetic subjects had reduced muscle glucose uptake (P < 0.01) and decreased insulin stimulation of tyrosine phosphorylation of insulin receptor substrate-1 and its ability to associate with phosphatidylinositol 3-kinase (P < 0.01 and P < 0.05). Because it was assayed by total hydroxyproline content, collagen abundance was increased in muscle from not only type 2 diabetic patients but also nondiabetic obese subjects (0.26 ± 0.05, 0.57 ± 0.18, and 0.67 ± 0.20 μg/mg muscle wet wt, lean controls, obese nondiabetics, and type 2 diabetics, respectively), indicating that hyperglycemia itself could not be responsible for this effect. Immunofluorescence staining of muscle biopsies indicated that there was increased abundance of types I and III collagen. We conclude that changes in the composition of the extracellular matrix are a general characteristic of insulin-resistant muscle.
KW - Extracellular matrix
KW - Insulin resistance
KW - Type 2 diabetes mellitus
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U2 - 10.1152/ajpendo.00202.2005
DO - 10.1152/ajpendo.00202.2005
M3 - Article
C2 - 16249255
AN - SCOPUS:33645047449
SN - 0193-1849
VL - 290
SP - E560-E565
JO - American Journal of Physiology - Endocrinology and Metabolism
JF - American Journal of Physiology - Endocrinology and Metabolism
IS - 3
ER -