Influence of the interaction between the adiponectin G276T polymorphism and body mass index on lipid levels in healthy children

Coronary Heart Disease in Type 2 Diabetes Mellitus: Genetic Factors and Their Mechanisms, Gene-Gene, and Gene-Environment Interactions in the Asian Populations

Asians are more susceptible to type 2 diabetes mellitus (T2D) and its coronary heart disease (CHD) complications than the Western populations, possibly due to genetic factors, higher degrees of obesity, insulin resistance, and endothelial dysfunction that could occur even in healthy individuals. The genetic factors and their mechanisms, along with gene-gene and gene-environment interactions associated with CHD in T2D Asians, are yet to be explored. Therefore, the objectives of this paper were to review the current evidence of genetic factors for CHD, summarize the proposed mechanisms of these genes and how they may associate with CHD risk, and review the gene-gene and gene-environment interactions in T2D Asians with CHD. The genetic factors can be grouped according to their involvement in the energy and lipoprotein metabolism, vascular and endothelial pathology, antioxidation, cell cycle regulation, DNA damage repair, hormonal regulation of glucose metabolism, as well as cytoskeletal function and intracellular transport. Meanwhile, interactions between single nucleotide polymorphisms (SNPs) from different genes, SNPs within a single gene, and genetic interaction with environmental factors including obesity, smoking habit, and hyperlipidemia could modify the gene's effect on the disease risk. Collectively, these factors illustrate the complexities of CHD in T2D, specifically among Asians.

Meta-analysis of the association of ADIPOQ G276T polymorphism with insulin resistance and blood glucose

Insulin resistance (IR) is a major risk for the development of type 2 diabetes (T2D). Numerous studies have been conducted to determine the relationship of ADIPOQ G276T with IR and blood glucose, but the results are conflicting. We conducted a meta-analysis in this work to further investigate such an association. Published works were retrieved from PubMed and Embase databases. A pooled standardized mean difference (SMD) with 95 % confidence interval (CI) was calculated under a dominant model using a random effect model. Twenty-five studies involving 7,480 subjects were included in the meta-analysis. A significant association of G276T polymorphism with homeostasis model assessment insulin resistance index (HOMA-IR) was observed after excluding studies with obvious heterogeneity by performing influence analysis (SMD = -0. 08, 95 % CI -0.15 to -0.01, p = 0.019) and Galbraith plot analysis (SMD = -0.08, 95 % CI -0.14 to -0.02, p = 0.005). In the subgroup analysis, Asians with TG/TT genotypes were found to have a significantly decreased degree of HOMA-IR (SMD = -0.13, 95 % CI -0.20 to -0.07, p < 0.001). The association of G276T with IR or blood glucose for the subgroups (obese, male, and T2D) was also significant. However, the results may not be reliable for small sample sizes. The current meta-analysis suggested that the G276T polymorphism may genetically affect IR using HOMA-IR as an index, and the effect of this polymorphism on IR particularly exists in Asians.

Interactions between ADIPOQ gene variants and dietary monounsaturated: saturated fatty acid ratio on serum lipid levels in Korean children

BACKGROUND AND AIMS

Adiponectin plays important roles in the regulation of insulin action and metabolism of glucose and lipids. We investigated whether ADIPOQ genetic variants are associated with serum lipid levels in Korean children and whether those influences might be modulated by dietary factors such as dietary monounsaturated fatty acid to saturated fatty acid ratio (MUFA:SFA).

METHOD AND RESULTS

The study included a population-based sample of 687 children aged 7-11 years in Gwacheon city, Kyunggi Province, Korea. Anthropometric and biochemical measurements and ADIPOQ genotype (-11377 C/G, +45 T/G, and +276 G/T) were determined. Dietary intake was estimated with a self reported 3-day food diary. The -11377 G allele carriers had significantly higher serum total cholesterol and LDL cholesterol compared to non-carriers. When dietary MUFA:SFA ratio was dichotomized (MUFA:SFA ≥ 1 or <1), the aggravating effects of the minor allele on serum total and LDL cholesterol were only present when the MUFA:SFA ratio was <1. Additionally, we observed that the ADIPOQ haplotype influenced serum total and LDL cholesterol levels. G-T-G haplotype carriers had higher total and LDL cholesterol levels than non-G-T-G carriers. The deleterious effect of ADIPOQ G-T-G haplotype to increase serum total and LDL cholesterol could be seen only when the MUFA:SFA ratio was <1.

CONCLUSION

In this present study, we found interaction effects between ADIPOQ genetic variants and dietary MUFA:SFA ratio on serum lipid levels in Korean children. These results suggest that individual genetic information and dietary fatty acid intake information should be assessed together to achieve an effective outcome for reducing the atherogenic lipid profile.

Association of the ADIPOQ T45G polymorphism with insulin resistance and blood glucose: a meta-analysis

Results of published studies on the association of the ADIPOQ T45G polymorphism with insulin resistance (IR) and blood glucose are conflicting. In this study, we performed a meta-analysis to further investigate such an association. Articles that evaluate the effect of the T45G polymorphism on IR and blood glucose were identified from the PubMed and Embase databases. Five indices, including fasting blood glucose (FBG), fasting insulin (F-insulin), 2-h blood glucose (2-h BG), 2-h insulin, and homeostasis model assessment insulin resistance index (HOMA-IR), were used to assess the effects of the T45G polymorphism on IR and blood glucose under a dominant model. 24 articles involving 7630 subjects were included. Twenty-two studies on FBG, 17 on F-insulin, 20 on HOMA-IR, and 3 on 2-h BG were included. No study on 2-h insulin was found. This meta-analysis revealed no significant association between the ADIPOQ T45G polymorphism and IR and blood glucose in the overall population and subgroup subjects under a dominant model, regardless of whether FBG, F-insulin, 2-h BG, or HOMA-IR was used. The present meta-analysis indicated that the mutation allele may have no function in IR development. The ADIPOQ T45G polymorphism is not associated with IR and blood glucose.

Associations between two single nucleotide polymorphisms of the adiponectin gene, its circulating concentrations and cardiometabolic risk factors in prepubertal children with and without abdominal obesity

BACKGROUND

The adiponectin gene has been identified as a susceptibility locus for metabolic syndrome, diabetes and cardiovascular disease.

AIM

To examine the influence of two single nucleotide polymorphisms (SNPs) of this gene (+276G>T and +45T>G) on circulating adiponectin concentrations, and to evaluate their relationship with adiposity and cardiometabolic risk factors in prepubertal children with and without abdominal obesity.

MATERIAL AND METHODS

168 children (78M, 6-10 yr) were examined, divided into three groups based on waist circumference (WC). Auxological and biochemical parameters were measured by standard procedures. Adiponectin SNPs were genotyped using TaqMan allelic discrimination assays.

RESULTS

Adiponectin concentration correlated inversely with measures of adiposity (rBMIz-score=-0.211, pBMIz-score=0.007; rwc=-0.210, pwc=0.008; rwc/height=-0.215, pwc/height=0.006), and was significantly influenced by blood glucose, insulin and systolic blood pressure (SBP). The +276T-allele carriers had higher SBP and diastolic BP compared to GG-homozygotes (p<0.05), and expressed higher obesity-related measures and lower adiponectin concentrations. As to the +45T>G SNP, the GGsubject had higher total cholesterol and LDL-C concentrations compared to the T-allele carriers (p<0.05), showing worse obesity measures, higher triglyceride, glucose and insulin and lower serum adiponectin values.

CONCLUSION

Genetic variants of the adiponectin gene had an impact on adiposity, adiponectin concentrations and some cardiometabolic variables among prepubertal children.