Visceral fat dominant distribution in male type 2 diabetic patients is closely related to hepatic insulin resistance, irrespective of body type

Abstract

Background: All previous studies that investigated the association between abdominal fat distribution and insulin resistance evaluated subcutaneous and visceral fat area and/or volume, but these values were not related to the body type of each subject. In the present study we have examined the association between abdominal fat distribution and peripheral (muscle)/hepatic sensitivity to insulin using the visceral to abdominal subcutaneous fat area ratio (VF/SF ratio) in male patients with type 2 diabetes mellitus. This ratio defines the predominancy of visceral or subcutaneous abdominal adiposity, independent of the body type of each individual.

Methods: Thirty-six type 2 diabetic male patients underwent a euglycemic insulin clamp (insulin infusion rate = 40 mU/m2 x min) with 3-3H-glucose to measure insulin-mediated total body (primarily reflects muscle) glucose disposal (TGD) and suppression of endogenous (primarily reflects liver) glucose production (EGP) in response to a physiologic increase in plasma insulin concentration. Abdominal subcutaneous (SF) and intraabdominal visceral fat (VF) areas were quantitated with magnetic resonance imaging (MRI) at the level of L4-5.

Results: TGD and TGD divided by steady state plasma insulin concentration during the insulin clamp (TGD/SSPI) correlated inversely with body mass index (BMI), total fat mass (FM) measured by 3H2O, SF and VF areas, while VF/SF ratio displayed no significant relationship with TGD or TGD/SSPI. In contrast, EGP and the product of EGP and SSPI during the insulin clamp (an index hepatic insulin resistance) correlated positively with VF/SF ratio, but not with BMI, FM, VF or SF.

Conclusion: We conclude that, independent of the individual's body type, visceral fat dominant accumulation as opposed to subcutaneous fat accumulation is associated with hepatic insulin resistance, whereas peripheral (muscle) insulin resistance is more closely related to general obesity (i.e. higher BMI and total FM, and increased abdominal SF and VF) in male patients with type 2 diabetes.

Figure 1

Relationship between total body glucose disposal (TGD) during the insulin clamp (top), endogenous glucose production during the insulin clamp (middle), and fasting plasma free fatty acid (FFA) concentration (lower) versus body mass index (BMI), total body fat mass (FM), abdominal subcutaneous fat (SF) area and visceral fat (VF) area at the L_4–5 vertebral level.

Figure 2

Relationship between plasma FFA concentration during the insulin clamp versus glucose disposal (TGD) during the insulin clamp divided by the steady state plasma insulin concentration (SSPI) during the insulin clamp (top) and the product of EGP × SSPI during the insulin clamp.

Figure 3

Transverse cross-sectional magnetic resonance image at the L_4–5 vertebral level in a study subject whose visceral to abdominal subcutaneous fat (VF/SF) ratio was increased (bottom) or decreased (upper).