Relation of G1359A polymorphism of the cannabinoid receptor (CB1) gene with metabolic syndrome by ATP III classification

On the Role of Central Type-1 Cannabinoid Receptor Gene Regulation in Food Intake and Eating Behaviors

Different neuromodulatory systems are involved in long-term energy balance and body weight and, among these, evidence shows that the endocannabinoid system, in particular the activation of type-1 cannabinoid receptor, plays a key role. We here review current literature focusing on the role of the gene encoding type-1 cannabinoid receptors in the CNS and on the modulation of its expression by food intake and specific eating behaviors. We point out the importance to further investigate how environmental cues might have a role in the development of obesity as well as eating disorders through the transcriptional regulation of this gene in order to prevent or to treat these pathologies.

G1359A Polymorphism of the Cannabinoid Receptor 1 Is Not Associated with Overweight and Dyslipidemia in Young Northeastern Mexicans

There is extensive evidence to believe that the endocannabinoid system plays an important role in energy homeostasis through a variety of mechanisms. This study aimed to analyze the association between polymorphism rs12720071 of the cannabinoid type 1 receptor (CNR1) gene with dyslipidemia and overweight in young, healthy Mexicans. The association was analyzed with a logistic regression model and expressed as odds ratio (OR). A total of 148 individuals agreed to participate. Overall, the serum concentrations of lipids were found to be in the normal range. However, females presented higher levels of cholesterol and low-density lipoprotein (LDL) than males [probability value (p) = <0.05]. In addition, females presented higher risk of being overweight (BMI: >25) [OR = 3.57; 95% confidence interval (CI): 1.05-12.20; p = 0.04], than males. Our results suggest that this polymorphism could influence BMI in young females.

Genetic polymorphisms of the endocannabinoid system in obesity and diabetes

The endocannabinoid system (ECS) is involved in many physiological processes including fertility, pain and energy regulation. The aim of this systematic review was to examine the contribution of single nucleotide polymorphisms (SNPs) of the ECS to adiposity and glucose metabolism. Database searches identified 734 articles, of which 65 were included; these covered 70 SNPs in genes coding for cannabinoid receptors 1 and 2 (CB₁ , CB₂ ), fatty acid amide hydrolase (FAAH) and N-acyl phosphatidylethanolamine phospholipase D (NAPE-PLD). No studies included SNPs relating to monoacylglycerol lipase or diacylglycerol lipase. The CB₁ receptor SNP rs1049353 showed 17 associations with lower body mass index (BMI) and fat mass (five studies). It also showed three associations with lower insulin levels (one study). Conversely, the CB₁ receptor SNP rs806368 was associated with increased BMI and waist circumference (two studies). The FAAH SNP rs324420 was associated with increased obesity (three studies). A haplotype of NAPE-PLD was associated with decreased BMI (one study). A total of 60 SNPs showed no association with any measured outcome. This review suggests a complex but important role of ECS SNPs in energy and glucose metabolism.

The role of the CNR1 gene in schizophrenia: a systematic review including unpublished data

Objective:

Schizophrenia is a multifactorial disorder. It is known that a combination of extensive multiple common alleles may be involved in its etiology, each contributing with a small to moderate effect, and, possibly, some rare alleles with a much larger effect size. We aimed to perform a systematic review of association studies between schizophrenia (and its subphenotypes) and polymorphisms in the CNR1 gene, which encodes cannabinoid receptors classically implicated in schizophrenia pathophysiology, as well as to present unpublished results of an association study in a Brazilian population.

Methods:

Two reviewers independently searched for eligible studies and extracted outcome data using a structured form. Papers were retrieved from PubMed and ISI Web of Knowledge using the search term schizophrenia in combination with CNR1 or CB1 or cannabinoid receptor. Twenty-four articles met our inclusion criteria. We additionally present data from a study of our own comparing 182 patients with schizophrenia and 244 healthy controls.

Results:

No consistent evidence is demonstrated.

Conclusion:

Some seemingly positive association studies stress the need for further investigations of the possible role of endocannabinoid genetics in schizophrenia.

Effects of a High-Protein/Low-Carbohydrate versus a Standard Hypocaloric Diet on Weight and Cardiovascular Risk Factors during 9 Months: Role of a Genetic Variation in the Cannabinoid Receptor Gene (CNR1) (G1359A Polymorphism)

Objective: We decided to investigate the role of this polymorphism on cardiovascular risk factors and weight loss secondary to a high-protein/low-carbohydrate vs. a standard hypocaloric diet (1,000 kcal/day) over a period of 9 months. Material and methods: A nutritional evaluation was performed at the beginning and at the end of a 9-month period in which subjects received 1 of 2 diets (diet HP: high protein/low carbohydrate vs. S: standard diet). Results: One hundred and four patients (54.7%) had the genotype G1359G and 86 (45.3%) patients had G1359A (77 patients, 25.8%) or A1359A (9 patients, 3.7%) (A-allele-carriers). In subjects with both genotypes, the body mass index, weight, fat mass, waist circumference and systolic blood pressures decreased with both diets. After the diet type HP and in subjects with both genotypes, the glucose, leptin, total cholesterol, LDL-cholesterol, insulin and HOMA-R levels decreased. After diet S and in all subjects, the total cholesterol, LDL cholesterol and leptin levels decreased, too. Conclusion: Our interventional study didn't show a relationship between the rs1049353 CNR-1 polymorphism and body weight response after two different hypocaloric (low carbohydrate/high protein vs. standard) diets over a period of 9 months. However, a low-carbohydrate/high-protein diet for 9 months improved glucose metabolism in subjects with both genotypes.

Polymorphism G1359A of the cannabinoid receptor gene (CNR1): allelic frequencies and influence on cardiovascular risk factors in a multicentre study of Castilla-Leon

BACKGROUND

A polymorphism (1359 G/A) of the CNR1 gene was reported as a common polymorphism in Caucasian populations and was related to cardiovascular risk factors. The present study aimed to investigate the allelic distribution of polymorphism (G1359A) of the CB1 receptor gene in a geographical area of Spain (Community of Castilla y Leon) and to evaluate the influence of this polymorphism on obesity anthropometric parameters and cardiovascular risk factors in the fasted state in obese patients.

METHODS

A population of 341 obese subjects was analysed. Tetrapolar electrical bioimpedance measurement, blood pressure measurement, a serial assessment of nutritional intake with 3 days of written food records and a biochemical analysis were all performed.

RESULTS

One hundred and seventy-seven patients (51.9%) had the genotype G1359G (wild-type group) and 164 (48.1%) patients were A carriers: G1359A (136 patients; 39.9%) or A1359A (28 patients; 8.2%) (mutant type group). The Health Area of Palencia had a lower frequency of wild-type genotype and G allelic frequency than all the other Health Areas. Segovia and Burgos Areas had a higher frequency of wild-type genotype and G allelic frequency than the other Health Areas. High-density lipoprotein (HDL) cholesterol was higher in the mutant type group and blood tryglicerides were lower in the same group.

CONCLUSIONS

In conclusion, the novel finding of the present study is the association of the mutant type group G1359A and A1359A with a better lipid profile (triglycerides and HDL cholesterol) than the wild-type group. The frequencies of this polymorphism are different among Health Areas of Castilla y Leon (Spain).

Common polymorphism in the cannabinoid type 1 receptor gene (CNR1) is associated with microvascular complications in type 2 diabetes

Endocannabinoids exert their biological effects via interaction with G-protein coupled cannabinoid receptors CB1 and CB2. Polymorphisms in the CNR1 gene (encoding CB1 receptor) were previously found to be associated with dyslipidemia and cardiovascular diseases. We investigated a role of the polymorphism in CNR1 gene in type 2 diabetes and its complications. The study involved 667 T2DM patients and 450 healthy individuals. All subjects were genotyped for G1359A polymorphism by PCR-RFLP procedure. Genotype frequencies did not differ significantly between patients and controls. The statistically significant differences were seen between T2DM patients with diabetic nephropathy (DN) and those without it (OR for risk allele 2.84, 95% CI 2.04-3.94, p<0.0001). There were also differences between patients with diabetic retinopathy (DR) and those without DR (OR for risk allele 1.81, 95% CI 1.30-2.53, p=0.0005). No differences were observed in diabetic neuropathy. The A allele was more frequent in patients with coexisting cardiovascular disease (CVD) compared to patients without CVD (p=0.0044). The novel finding of our study is the association of the G1359A polymorphism with diabetic nephropathy and diabetic retinopathy in patients with T2DM. This polymorphism was also associated with cardiovascular disease in the patient group.

CNR1 gene and risk of the metabolic syndrome in patients with schizophrenia

Metabolic disturbances are more prevalent in patients with schizophrenia (SCZ) than in the general population. The endocannabinoid system plays an important role in the regulation of dopamine transmission and several metabolic pathways, and the endocannabinoid receptor type 1 gene (CNR1) is considered a candidate gene for both SCZ and metabolic disorders. We examined whether genetic variation in CNR1 was associated with metabolic syndrome (MetS) in a naturalistic cohort of 407 patients with SCZ. The minor alleles of rs6928499, rs1535255, and rs2023239 were nominally associated with a lower risk of MetS [odds ratio (OR), 0.56; 95% confidence interval (CI), 0.37-0.84; P = 0.006; OR, 0.56; 95% CI, 0.37-0.84; P = 0.006; and OR, 0.44; 95% CI, 0.27-0.72; P = 0.001, respectively, adjusted for age, sex, duration of illness, clozapine or olanzapine treatment). These differences were mainly due to differences in high-density lipoprotein cholesterol and fasting glucose but not in body mass index or waist circumference. No significant association of the other polymorphisms (rs806377, rs1049353, rs6454674, and rs806379) with MetS was found. These results provide evidence that the prevalence of MetS is associated with the CNR1 gene in patients with SCZ during long-term treatment with antipsychotic treatment. Further studies are needed to uncover the exact molecular basis for this association, which could provide novel treatment targets for the MetS.

Relationship of -55C/T polymorphism of uncoupling protein 3 (UCP3) gene with metabolic syndrome by ATP III classification

BACKGROUND AND AIMS

The relation of -55C/T polymorphism of uncoupling protein 3 (UCP3) with metabolic syndrome (MS) has been evaluated only in one previous study with contradictory results. The aim of our study was to investigate the association of -55C/T polymorphism of UCP3 gene with MS.

DESIGN

A population of 817 obese Caucasian patients was analyzed in a cross-sectional survey. Genotype of UCP3 gene -55C/T was studied. To estimate the prevalence of MS , the definitions of the ATPIII were considered.

RESULTS

Five hundred and ninety-four patients (72.7%) had the genotype -55CC (wild group), whereas 223 patients (27.3%) had the genotype -55C/T. Genotype -5TT was not detected. Prevalence of mutant UCP genotypes was similar in patients with MS (75.7% wild genotype and 24.3% mutant genotype) and without MS (69.7% wild genotype and 30.3% mutant genotype). Odds ratio of MS wild vs. mutant genotype was 1.17 CI 95%: 0.99-1.38). Total cholesterol and low density lipoprotein (LDL) cholesterol concentrations were lower in mutant-type group than wild-type group in patients with MS. No differences in other parameters were detected between genotypes in the same group of MS.

CONCLUSION

-55C/T UCP polymorphism is not major risk factor for the MS. However, in mutant group of -55CC UCP3 gene in patients with MS, total cholesterol and LDL cholesterol were lower than wild-type patients.