Background: The effects of adiponectin on glucose and lipid metabolism are mediated by the adiponectin receptors, adipoR1 and adipoR2, which are mainly in liver and muscle. We investigated the presence of adiponectin receptors in intra-abdominal adipose tissue (IAAT) in obesity and diabetes and their association with adiponectin expression and components of the metabolic syndrome and/or other metabolic factors associated with atherosclerotic cardiovascular disease (ASCVD).
Methods: AdipoR1 and adipoR2 gene expression was measured by quantitative real time reverse transcription polymerase chain reaction in IAAT from lean and obese patients with or without diabetes type 2. Correlation between metabolic characteristics of obese patients and expression of these receptors was studied.
Results: Neither obesity nor diabetes were associated with changes in IAAT-adipoR1 expression. In contrast, IAAT-adipoR2 was decreased by 39.5% in obese non-diabetics and by 52.7% in obese diabetics when compared to lean subjects. AdipoR1 and adiponectin expression was associated in lean (r=0.943, P<0.005) and obese non-diabetic patients (r=0.74, P<0.01), whereas a positive correlation between adipoR2 and adiponectin expression was only found in the presence of diabetes (r=0.883, P<0.002). AdipoR1 expression was associated with plasma free fatty acids (FFA) concentration (r=0.76, P<0.04), and adipoR2 inversely correlated with plasma levels of triglycerides (r=-0.76, P<0.04) and apolipoprotein B (r=-0.74, P<0.05).
Conclusion: AdipoR1 expression in IAAT was not altered by obesity and/or diabetes and was related to plasma levels of FFA. IAAT-adipoR2 expression was reduced in obesity and diabetes and associated with components of metabolic processes leading to cardiovascular disease in obesity.