Altered pattern of cannabinoid type 1 receptor expression in adipose tissue of dysmetabolic and overweight patients

In overweight patients (OW), the increased peripheral activity of the endocannabinoid system in visceral adipose tissue (VAT) may be mediated by cannabinoid type I (CB I) receptor expression. We determined whether CB I receptor splice variants and messenger RNA (mRNA) levels in perirenal and Subcutaneous adipose tissues are associated with obesity and metabolic syndrome (MetS). Gene expression with multiple-primers real-time polymerase chain reaction (TaqMan; Applied Biosystem, Weiterstadt, Germany) was performed to study VAT and paired Subcutaneous adipose tissue (SAT) mRNA from 36 consecutive patients undergoing nephrectomy. Cannabinoid type I A and (CBIE mRNAs variants with the longer version of exon 4 were expressed. The CB I expression in perirenal VAT significantly correlated with body mass index (BMI). Paired subcutaneous/perirenal samples from normal-weight patients (BMI <25 kg/m(2)) showed higher CB I expression in SAT (P = .002), whereas in OW (BMI >= 25 kg/m(2)), the higher CBI expression was in VAT (P = .038). In unpaired samples, SAT of normal-weight patients had significantly higher CB1 mRNA levels compared with SAT of OW, whereas higher CB I expression (P = .009) was found in VAT of OW (n = 25). Overweight patients with increased visceral CB I expression had higher waist circumference (P < .01), insulin (P < .01), and homeostasis model assessment index (P < .01). In addition, patients with the MetS (n = 22) showed higher CB1 expression in perirenal adipose tissues (P = .007). Visceral adipose CB I expression correlated with BMI. Overweight patients and those with MetS showed a CB1 expression pattern Supporting a CBI-mediated overactivity of the endocannabinoid system in human VAT. (C) 2009 Elsevier Inc. All rights reserved.