Metallothionein-mediated antioxidant defense system and its response to exercise training are impaired in human type 2 diabetes

TY - JOUR

T1 - Metallothionein-mediated antioxidant defense system and its response to exercise training are impaired in human type 2 diabetes

AU - Scheede-Bergdahl, Celena

AU - Penkowa, Milena

AU - Hidalgo, Juan

AU - Olsen, David B

AU - Schjerling, Peter

AU - Prats, Clara

AU - Boushel, Robert

AU - Dela, Flemming

N1 - Keywords: Antioxidants; Case-Control Studies; Diabetes Mellitus, Type 2; Exercise; Gene Expression Regulation; Humans; Male; Metallothionein; Middle Aged; Muscle, Skeletal; Oxidative Stress; RNA, Messenger

PY - 2005

Y1 - 2005

N2 - Oxidative stress is implicated in diabetes complications, during which endogenous antioxidant defenses have important pathophysiological consequences. To date, the significance of endogenous antioxidants such as metallothioneins I and II (MT-I+II) in type 2 diabetes remains unclear. To examine the MT-I+II-mediated antioxidant capacity and its response to exercise training in the skeletal muscle of patients with type 2 diabetes, biopsies and blood samples were taken from 13 matched subjects (type 2 diabetes n = 8, control subjects n = 5) both before and after 8 weeks of exercise training. Immunohistochemical analysis revealed reduced MT-I+II levels in the skeletal muscle of type 2 diabetic subjects compared with control subjects. Control subjects produced a robust increase of MT-I+II in response to training; however, in type 2 diabetes, MT-I+II levels remained essentially unchanged. Significantly lower levels of MT-I+II were also detected in the plasma of type 2 diabetic subjects compared with control subjects. These results suggest that, in control subjects, the MT-I+II defense system is active and inducible within skeletal muscle tissue and plasma. In type 2 diabetes, reduced levels of MT-I+II in muscle and plasma, as well as the deficient MT-I+II response to exercise, indicate that this antioxidant defense is impaired. This study presents a novel candidate in the pathogenesis of complications related to oxidative stress in type 2 diabetes.

AB - Oxidative stress is implicated in diabetes complications, during which endogenous antioxidant defenses have important pathophysiological consequences. To date, the significance of endogenous antioxidants such as metallothioneins I and II (MT-I+II) in type 2 diabetes remains unclear. To examine the MT-I+II-mediated antioxidant capacity and its response to exercise training in the skeletal muscle of patients with type 2 diabetes, biopsies and blood samples were taken from 13 matched subjects (type 2 diabetes n = 8, control subjects n = 5) both before and after 8 weeks of exercise training. Immunohistochemical analysis revealed reduced MT-I+II levels in the skeletal muscle of type 2 diabetic subjects compared with control subjects. Control subjects produced a robust increase of MT-I+II in response to training; however, in type 2 diabetes, MT-I+II levels remained essentially unchanged. Significantly lower levels of MT-I+II were also detected in the plasma of type 2 diabetic subjects compared with control subjects. These results suggest that, in control subjects, the MT-I+II defense system is active and inducible within skeletal muscle tissue and plasma. In type 2 diabetes, reduced levels of MT-I+II in muscle and plasma, as well as the deficient MT-I+II response to exercise, indicate that this antioxidant defense is impaired. This study presents a novel candidate in the pathogenesis of complications related to oxidative stress in type 2 diabetes.

M3 - Journal article

C2 - 16249430

SN - 0012-1797

VL - 54

SP - 3089

EP - 3094

JO - Diabetes

JF - Diabetes

IS - 11

ER -