Genetic and Non-Genetic Determinants of Circulating Levels of Adiponectin in a Cohort of Chilean Subjects

Apolipoprotein E E3/E4 genotype is associated with an increased risk of type 2 diabetes mellitus complicated with coronary artery disease

OBJECTIVE

Dyslipidemia is a co-existing problem in patients with diabetes mellitus (DM) and coronary artery disease (CAD), and apolipoprotein E (APOE) plays an important role in lipid metabolism. However, the relationship between the APOE gene polymorphisms and the risk of developing CAD in type 2 DM (T2DM) patients remains controversial. The aim of this study was to assess this relationship and provide a reference for further risk assessment of CAD in T2DM patients.

METHODS

The study included 378 patients with T2DM complicated with CAD (T2DM + CAD) and 431 patients with T2DM alone in the case group, and 351 individuals without DM and CAD were set as controls. The APOE rs429358 and rs7412 polymorphisms were genotyped by polymerase chain reaction (PCR) - microarray. Differences in APOE genotypes and alleles between patients and controls were compared. Multiple logistic regression analysis was performed after adjusting for age, gender, body mass index (BMI), history of smoking, and history of drinking to access the relationship between APOE genotypes and T2DM + CAD risk.

RESULTS

The frequencies of the APOE ɛ3/ɛ4 genotype and ε4 allele were higher in the T2DM + CAD patients, and the frequencies of the APOE ɛ3/ɛ3 genotype and ε3 allele were lower than those in the controls (all p < 0.05). The T2DM + CAD patients with ɛ4 allele had higher level in low-density lipoprotein cholesterol (LDL-C) than those in patients with ɛ2 and ɛ3 allele (p < 0.05). The results of logistic regression analysis showed that age ≥ 60 years old, and BMI ≥ 24.0 kg/m2 were independent risk factors for T2DM and T2DM + CAD, and APOE ɛ3/ɛ4 genotype (adjusted odds ratio (OR) = 1.93, 95% confidence interval (CI) = 1.18-3.14, p = 0.008) and ɛ4 allele (adjusted OR = 1.97, 95% CI = 1.23-3.17) were independent risk factors for T2DM + CAD. However, the APOE genotypes and alleles were not found to have relationship with the risk of T2DM.

CONCLUSIONS

APOE ε3/ε4 genotype and ε4 allele were independent risk factors for T2DM complicated with CAD, but not for T2DM.

Associations of the Polymorphisms in ADIPOQ with Circulating Levels of Adiponectin and Lipids: A Meta-Analysis

The relationships between the rs266729, rs1501299, and rs2241766 polymorphisms in adiponectin gene (ADIPOQ) and circulating levels of adiponectin and lipids remain to be clarified. Databases including PubMed and Embase were searched for eligible studies. The random-effects model was used, and standardized mean difference (SMD) with 95% confidence interval (CI) was calculated to estimate the differences in circulating levels of adiponectin and lipids between the subjects with different genotypes. A total of 12 810, 17 319, and 21 361 subjects were identified in the analyses for the rs266729, rs1501299, and rs2241766 polymorphisms, respectively. G allele carriers of the rs266729 polymorphism had lower levels of adiponectin (SMD=-0.28, 95% CI=-0.43 to-0.12) and high-density lipoprotein cholesterol (HDL-C) (SMD=-0.10, 95% CI=-0.17 to-0.02) than CC homozygotes; T allele carriers of the rs1501299 polymorphism had higher levels of adiponectin (SMD=0.21, 95% CI=0.05 to 0.36) and HDL-C (SMD=0.09, 95% CI=0.04 to 0.15) and lower levels of triglycerides (SMD=-0.06, 95% CI=-0.12 to-0.01) than GG homozygotes; G allele carriers of the rs2241766 polymorphism had lower levels of adiponectin (SMD=-0.18, 95% CI=-0.31 to-0.05) and HDL-C (SMD=-0.12, 95% CI=-0.20 to-0.04) than TT homozygotes. This meta-analysis suggests that the rs266729, rs1501299, and rs2241766 polymorphisms of ADIPOQ are significantly associated with circulating levels of adiponectin and lipids, which may partly explain the associations between these polymorphisms and coronary artery disease.

A genetic analysis identifies haplotype at adiponectin locus: Association with the metabolic health and obesity phenotypes

BACKGROUND

Obesity and metabolic syndrome frequently co-exist and define obese individuals into different obesity phenotypes, such as metabolically healthy obese (MHO), metabolically unhealthy obese (MUO) and metabolically unhealthy normal weight (MUNW). Growing evidence suggests that genetic predisposition and environmental factors can explain the heterogeneity among these phenotypes.

METHODS

We conducted a case-control study including 130 MHO, 251 MUNW, 208 MUO and 336 health controls by genotyping 2 SNPs (rs2241766, rs1501299) in ADIPOQ to investigate possible associations between SNPs in the ADIPOQ gene with susceptibility to three obese phenotypes respectively in Chinese Han population. Unconditional logistic regressions were used to detect the association between ADIPOQ SNPs and MHO/MUNW/MUO risks.

RESULTS

Variant G allele of rs2241766 was associated with a reduced odds of MUO (additive model: Adjusted OR = 0.55; 95% CI = 0.40-0.75; P < 0.001) and no evidence of any significant association between rs2241766 and MHO phenotype (additive model: Adjusted OR = 0.84; 95% CI = 0.61-1.16; P = 0.306) or MUNW phenotype (additive model: Adjusted OR = 0.95; 95% CI = 0.73-1.24; P = 0.720) was found. Minor allele T of rs1501299 were significantly associated with decreased risk of MHO (Adjusted OR = 0.53; 95% CI = 0.37-0.76; P < 0.001) and MUNW (Adjusted OR = 0.63; 95% CI = 0.48-0.83; P = 0.001) in additive genetic model after correction for multiple testing.

CONCLUSIONS

The variant G allele of rs2241766 was negatively associated with risk of MUO and variant T allele of rs1501299 exhibited reduced odds for MHO and MUNW. Beyond that, future studies are warranted to validate and extend our findings.

Leptin level as a biomarker of uncontrolled eating in obesity and overweight

BACKGROUND

Uncontrolled eating (UE) showed important relationships with the development of obesity. Homeostatic regulations of feeding and energy balance, as well as hedonic eating, are regulated by leptin.

AIMS

The aims of this study were (1) to assess eating behaviors of Algerian adults as measured by the 51-item eating inventory; we also evaluate changes in the Three-Factor Eating Questionnaire (TFEQ) scores according to the body mass index (BMI) category; (2) to examine the association between the scores of the three TFEQ factors and the BMI values of the participants; and (3) to examine whether leptin concentrations are associated with eating behavior. Our hypothesis is that participants with obesity and high concentrations of leptin might display uncontrolled eating behavior.

METHODS

The subjects were 190 participants (60 obese, 60 overweight, and 70 lean subjects). The eating behavior was measured by using the 51-item eating inventory. Serum insulin concentrations were assessed by radioimmunoassay and were used to calculate homeostasis model assessment (HOMA). Serum leptin was quantified by the enzyme-linked immunosorbent assay (ELISA).

RESULTS

Obese and overweight subjects showed hyperphagic behavior, i.e., uncontrolled eating. The logistic regression analysis showed an effect of leptin, HOMA, uncontrolled eating, and emotional eating on BMI. Leptin levels were associated with the uncontrolled eating and influenced by insulin sensitivity.

CONCLUSIONS

The uncontrolled eating reflects hyperphagic eating behavior in obese and overweight subjects. Coexistence of uncontrolled eating and high level of leptin demonstrates a state of leptin resistance resulting in an inability to detect satiety. High circulating leptin can be considered a potential biomarker of uncontrolled eating.

Polymorphisms in Genes Involved in the Leptin-Melanocortin Pathway are Associated with Obesity-Related Cardiometabolic Alterations in a Southern Chilean Population

BACKGROUND

Polymorphisms in genes encoding proteins of the leptin-melanocortin pathway have been associated with obesity. The involvement of these polymorphisms with changes in body mass index (BMI) and anthropometric measures could also imply a contribution to the risk of metabolic syndrome (MetS) and metabolic alterations. We evaluated the relationship of leptin-melanocortin system polymorphisms with obesity, MetS, and other metabolic alterations in Southern Chilean individuals.

METHODS

Two-hundred individuals were grouped as normoweight (BMI 18.0-24.9 kg/m²), overweight (BMI 25.0-29.9 kg/m²), and obese (BMI ≥ 30 kg/m²) or according to MetS status. Anthropometric measures (BMI, abdominal circumference, waist-to-hip ratio [WHR]) and biochemical parameters (glycemia and lipid profile) were evaluated. Polymorphisms LEP rs7799039, LEPR rs1137101, MC3R rs3746619 and rs3827103, and MC4R rs17782313 were evaluated by real-time PCR using allelic discrimination assays.

RESULTS

LEPR rs1137101 GG genotype was related to reduced risk of obesity (odds ratio [OR] 0.26, 95% confidence interval [CI] 0.08-0.79; p = 0.018) and MetS (OR 0.36, 95% CI 0.15-0.88; p = 0.024), but it was not significant after Bonferroni correction for multiple tests as compared to the AA genotype (p > 0.01). Moreover, LEPR rs1137101 allele G (AG + GG) was related to lower BMI and WHR (p < 0.01). Further multiple linear regression analysis demonstrated that this genotype was also responsible for reduced BMI in 2.44 kg/m² and WHR in 0.033 units. MC4R rs17782313 allele C (TC + CC) was slightly associated with diminished risk of MetS (OR 0.48, 95% CI 0.23-0.98; p = 0.040) and reduced BMI values in 1.95 kg/m² (p < 0.05). Regarding lipid profile, LEPR rs1137101 allele G carriers had lower triglycerides and very-low-density lipoprotein (VLDL) cholesterol, whereas individuals carrying the MC4R rs17782313 allele C had higher high-density lipoprotein (HDL) cholesterol (p < 0.01). LEP rs7799039 allele A (GA + AA) was slightly associated with reduced total and low-density lipoprotein (LDL) cholesterol (p < 0.05).

CONCLUSIONS

These results suggest that polymorphisms at LEP, LEPR, and MC4R may be useful biomarkers of obesity-related cardiometabolic alterations in our population.