Tackling the genetic bases of metabolic syndrome: a realistic objective?

Are endocannabinoid type 1 receptor gene (CNR1) polymorphisms associated with obesity and metabolic syndrome in postmenopausal Polish women?

OBJECTIVE

The aim of this study was to determine whether genetic variation at the cannabinoid receptor-1 (CNR1) locus could have an effect on adiposity, fat distribution and obesity-related metabolic disorders in Polish postmenopausal women.

DESIGN AND SUBJECTS

The A3813G (rs12720071), G1422A (rs1049353), A4895G (rs806368) and rs806381, rs10485170, rs6454674 and rs2023239 single-nucleotide polymorphisms of CNR1 were genotyped in 348 randomly selected postmenopausal women aged 50-60 years recruited from the Wroclaw city population.

MEASUREMENTS

CNR1 genotypes, anthropometric measures (body mass index (BMI), waist circumference (WC) and body fat distribution by dual energy X-ray absorptiometry) and metabolic parameters (glucose, lipid profile and Fasting Insulin Resistance Index for insulin resistance) were determined.

RESULTS

The 3813G allele was not significantly associated with higher body mass, BMI, WC, total fat or fat percentage, but was associated with higher android fat deposit (2971.78±1655.08 vs 2472.64±1300.53, P=0.007) and percentage of android fat (37.59±8.45 vs 35.66±7.63, P=0.062). No associations for the G1422A, A4895G, rs806381, rs10485170, rs6454674 and rs2023239 variants were observed.

CONCLUSIONS

There is an association of the variants of CNR1 with obesity-related phenotypes in Polish postmenopausal women. As cannabinoid receptor type 1 is a drug target for obesity, pharmacogenetic receptor gene analysis of obesity treatment by endocannabinoid blockade may be of interest to identify the best responders.

Genetic variations at the endocannabinoid type 1 receptor gene (CNR1) are associated with obesity phenotypes in men

CONTEXT

The endocannabinoid system modulates food intake and body weight in animal models. Treatment with the cannabinoid type 1 receptor blocker, rimonabant, reduces body weight in obese individuals.

OBJECTIVE

The aim of this study was to determine whether single nucleotide polymorphisms of the gene encoding cannabinoid type 1 receptor, CNR1, are associated with body fat mass and distribution in two independent samples of white European adult men.

DESIGN, SETTING, AND PARTICIPANTS

The 3813A/G and 4895A/G single nucleotide polymorphisms at the exon 4 of CNR1 were genotyped in 930 participants to the Olivetti Prospective Heart Study (OPHS) in Southern Italy and in 216 participants to the Wandsworth Heart and Stroke Study in the United Kingdom. Retrospective analysis was also performed on an OPHS subsample (n = 360) for which anthropometric data from 1987 and 1994-1995 examinations were available.

MAIN OUTCOME MEASURES

CNR1 genotypes and anthropometric measures of body fat distribution were determined.

RESULTS

In the OPHS study, the 3813G allele was associated with increased subscapular skinfold thickness (24.2 +/- 9.1 vs. 22.8 +/- 7.7 mm; P = 0.031) and waist circumference (WC) (99.1 +/- 8.8 vs. 97.7 +/- 8.8 cm; P = 0.050). No association was observed with 4895A/G variant. Haplotype analysis confirmed that the unique haplotype carrying the 3813G was associated with increased WC and subscapular skinfold thickness. Similar results were observed in the OPHS retrospective subsample and the Wandsworth Heart and Stroke Study sample. In the latter, the 3813G was associated with increased WC (96.8 +/- 11.3 vs. 91.6 +/- 10.4 cm; P = 0.006).

CONCLUSIONS

Genetic variants at CNR1 are associated with obesity-related phenotypes in men. The detection of polymorphic variants in genes involved in the process of fat accumulation may help identify specific targets for pharmacological treatment of obesity and related metabolic abnormalities.