Adiponectin gene variants, adiponectin isoforms and cardiometabolic risk in type 2 diabetic patients

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.

Functional Haplotypes in the ADIPOQ Gene are Associated with Underweight, Immunosuppression and Viral Suppression in Kenyan HIV-1 Infected Antiretroviral Treatment Naive and Experienced Injection Substance Users

Background

Human immunodeficiency virus and injection substance use have an influence on genes and gene expression. These effects could be beneficial or detrimental in defining disease outcomes. Adiponectin gene is key in modulating metabolic and immunoregulatory functions. Understanding the effects of human immunodeficiency virus and injection substance use on the gene in the context of antiretroviral therapy is important for predicting disease outcomes.

Methods

This cross-sectional genetic study determined polymorphisms in the promoter region of adiponectin gene. Two variants were analyzed: rs2241766 and rs266729. Polymorphisms were associated with clinical markers of disease outcome; underweight, immunosuppression and viral suppression. The variants were genotyped via random fragment length polymorphism.

Result

GC haplotype was associated with higher odds of having underweight (OR, 2.21; 95% CI, 1.83-4.60; P=0.008 vs. OR, 2.30; 95% CI, 1.89-4.71; P=0.006) in antiretroviral treatment - naive and experienced injection substance users and immunosuppression (OR, 1.90; 95% CI 1.67-3.98, P=0.041) in naive. Bonferroni correction revealed GC haplotype carriers only to have low body mass index in both naive (median, 14.8; IQR, 3.2 kg/m²; P=0.002) and experienced (median, 15.2; IQR, 3.2 kg/m²; P=0.002) injection substance users. Circulating total adiponectin levels were higher in naive (median, 19.5; IQR, 7.9 µg/ml) than - experienced (median, 12.0; IQR, 4.4 µg/ml) injection substance users (P=0.0001). GC carriers presented with low serum adiponectin levels in both study groups.

Conclusion

The study revealed haplotypes of adiponectin gene at loci rs2241766 and rs266729 that could determine disease outcomes in human immunodeficiency virus -1 antiretroviral treatment- naive and experienced injection substance users.

Gene polymorphisms of Patatin-like phospholipase domain containing 3 (PNPLA3), adiponectin, leptin in diabetic obese patients

Obesity leads a crucial importance in metabolic disorders, as well as type 2 diabetes mellitus. Our present study was designed to assess the potential role of irisin, adiponectin, leptin and gene polymorphism of PNPLA3, leptin and adiponectin as predictive markers of diabetes associated with obesity. One hundred eighty subjects were distributed to three groups including; healthy non-diabetic non obese volunteers as a control group, diabetic non obese group, and diabetic obese group (n = 60 for each group). Fasting blood samples of all groups were collected to determine fasting blood glucose, insulin levels, insulin resistance, total cholesterol, high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), triacylglycerol, irisin, adiponectin, leptin; as well as, polymorphism of PNPLA3, adiponectin and leptin. The results showed that glucose, insulin resistance, total cholesterol, irisin, leptin, LDL-C, triacylglycerol concentrations were significantly increased, however, insulin, HDL-C, adiponectin were significantly decreased in diabetic obese patients in relation to diabetic non-obese patients as well as in healthy volunteers. The polymorphism of PNPLA3 rs738409 was linearly related to irisin and leptin but was not related with circulating concentrations of adiponectin. We concluded that increased irisin and leptin levels can predict the insulin resistance in obese patients. Moreover, patients who have mutant genotype of PNPLA3 I148 gene (rs738409) C>G, ADIPOQ gene (rs266729) G>C and LEP gene (rs2167270) G>A showed a significant higher susceptibility rate for DM in obese people than those with wild type. This could be considered as an adjustable retort to counter the impact of obesity on glucose homeostasis.

Genetic Risk Factors of Intracranial Atherosclerosis

PURPOSE OF REVIEW

Intracranial atherosclerosis (ICAS) is the most common cause of stroke throughout the world. It also increases the risk of recurrent stroke and dementia. As a complex and multifactorial disease, ICAS is influenced by multiple genetic, biological, and environmental factors. This review summarizes the candidate gene and genome-wide studies aimed at discovering genetic risk factors of ICAS.

RECENT FINDINGS

Numerous studies have focused on the association between single-nucleotide polymorphisms (SNPs) of atherosclerosis-related genes and the risk of ICAS. Variants in adiponectin Q (ADIPOQ), ring finger protein 213 (RNF213), apolipoprotein E (APOE), phosphodiesterase 4D (PDE4D), methylenetetrahydrofolate reductase (MTHFR), lipoprotein lipase (LPL), α-adducin (ADD1) genes, angiotensin-converting enzyme (ACE), and other genes related to renin-angiotensin-aldosterone system have been associated with ICAS. We review the available evidences on the candidate genes and SNPs associated with genetic susceptibility to ICAS, and point out future developments of this field. Genetic discoveries could have clinical implications for intracranial atherosclerotic disease.

Associations between Adiponectin Gene Variability, Proinflammatory and Angiogenetic Markers: Implications for Microvascular Disease Development in Type 2 Diabetes Mellitus?

BACKGROUND

Adiponectin gene (ADIPOQ) variability may affect the risk for type 2 diabetes mellitus (T2DM) but it remains unclear whether it is involved in microvascular complications.

OBJECTIVE

To explore the impact of ADIPOQ variability on markers of inflammation and angiogenesis in T2DM.

METHODS

Overall, 220 consecutive T2DM patients from our outpatient diabetic clinic were genotyped for G276T (rs1501299) and T45G (rs2241766) single nucleotide polymorphisms of ADIPOQ gene. Serum levels of interleukin-6 (IL-6), intercellular adhesion molecule-1 (ICAM-1), vascular endothelial growth factor (VEGF) were measured by enzyme-linked immunosorbent assay and high sensitivity Creactive protein (hsCRP) by immunonephelometry.

RESULTS

Homozygosity for the G allele on rs2241766 was associated with significantly lower serum VEGF and ICAM-1 levels compared with other genotype groups, but had no effect on IL-6. Genetic variability on rs1501299 was not associated with either VEGF or ICAM-1 levels, but T homozygotes for rs1501299 had significantly lower IL-6 concentrations compared with G carriers. Furthermore, the presence of the G allele on rs2241766 was associated with significantly lower HbA1c, whereas no associations were observed for both body mass index and hsCRP with either rs2241766 or rs1501299.

CONCLUSION

Genetic variability on adiponectin gene was associated with serum levels of inflammatory and angiogenetic markers. Further research is required to elucidate the role of adiponectin in the development and/or progression of microvascular disease in T2DM patients.

Changes in serum adipokines profile and insulin resistance in patients with rheumatoid arthritis treated with anti-TNF-α

Background: Rheumatoid arthritis (RA) is a chronic inflammatory joint disease characterized by an altered glucose and lipid metabolism. Tumor necrosis factor alpha (TNF-α) is involved in the pathogenesis of both RA and metabolic syndrome. This study evaluated the effects of anti-TNF-α agents (adalimumab, etanercept, infliximab) on lipid and glucose metabolism in patients with RA.Methods: A total of 33 RA, biological therapy-naive patients were recruited. Changes in Disease Activity, Body Mass Index, resistin, leptin and adiponectin serum levels, lipid profile, atherogenic index, insulin sensitivity index, and insulin resistance index were evaluated at baseline and after anti-TNF-α treatments.Results: Anti-TNF-α treatment was effective in reducing disease activity. An inverse relationship between disease activity and adiponectin levels was found, whereas leptin and resistin levels directly correlated with disease activity. TNF-α therapy significantly reduced leptin, resistin, and increased adiponectin. TNF-α inhibition resulted in a reduction of atherogenic index and insulin resistance index while increased insulin sensitivity index.Conclusion: Anti-TNF-α agents could have a crucial role in modifying the impact of lipid profile and glucose levels dysregulation in RA patients. TNF-α inhibition may be a potential strategy for the prevention of metabolic syndrome and could play a role in the reduction of cardiovascular risk in RA.

The relationship between circulating adiponectin, ADIPOQ variants and incident cardiovascular disease in type 2 diabetes: The Fremantle Diabetes Study

AIMS

To investigate the relationship between serum adiponectin, ADIPOQ variants and haplotypes, and cardiovascular disease (CVD) in type 2 diabetes (T2D).

METHODS

Baseline data including serum total adiponectin and 21 ADIPOQ polymorphisms were available for 1076 participants (mean age 64.0 years, 49.4% males) in a community-based cohort followed for an average of 12 years.

RESULTS

During 8843 patient-years of follow-up for coronary heart disease (CHD), 13,494 patient-years for ischaemic stroke (IS) and 12,028 patient-years for heart failure (HF), 40.4%, 11.8% and 31.9% of patients experienced a first episode of CHD, IS or HF, respectively. In Cox regression after adjustment for the most parsimonious models, log_e(serum adiponectin) and the ADIPOQ variant rs12495941 were inversely associated with incident CHD (hazard ratio [95% confidence interval] 0.79 [0.65-0.98] and 0.64 [0.44-0.94], respectively), while rs1648707 was positively associated with incident IS (2.05 [1.37-3.06]; all P ≤ 0.028). In males, rs9860747 and rs17366568 predicted CHD (0.22 [0.05-0.92] and 1.50 [1.01-2.20]; P ≤ 0.042), while rs1648707 and rs1063537 predicted IS (2.36 [1.32-4.23] and 2.09 [1.17-3.72]; P ≤ 0.012). In females, rs10937273 predicted CHD via an interaction with serum adiponectin (0.43 [0.21-0.91]; P = 0.027), while rs864265 predicted IS (0.43 [0.21-0.88], P = 0.021). The associations between ADIPOQ variants and outcomes were supported by haplotype block analysis. Neither serum adiponectin nor ADIPOQ variants predicted HF.

CONCLUSIONS

Serum total adiponectin and gender-specific ADIPOQ variants predict CHD and IS, but not HF, independently of other risk factors in community-based patients with T2D. In contrast to some previous studies, there was no relationship between a high serum total adiponectin and CVD.

Associations between three common single nucleotide polymorphisms (rs266729, rs2241766, and rs1501299) of ADIPOQ and cardiovascular disease: a meta-analysis

Background

Inconsistencies have existed in research findings on the association between cardiovascular disease (CVD) and single nucleotide polymorphisms (SNPs) of ADIPOQ, triggering this up-to-date meta-analysis.

Methods

We searched for relevant studies in PubMed, EMBASE, Cochrane Library, CNKI, CBM, VIP, and WanFang databases up to 1st July 2017. We included 19,106 cases and 31,629 controls from 65 published articles in this meta-analysis. STATA 12.0 software was used for all statistical analyses.

Results

Our results showed that rs266729 polymorphism was associated with the increased risk of CVD in dominant model or in heterozygote model; rs2241766 polymorphism was associated with the increased risk of CVD in the genetic models (allelic, dominant, recessive, heterozygote, and homozygote). In subgroup analysis, significant associations were found in different subgroups with the three SNPs. Meta-regression and subgroup analysis showed that heterogeneity might be explained by other confounding factors. Sensitivity analysis revealed that the results of our meta-analysis were stable and robust. In addition, the results of trial sequential analysis showed that evidences of our results are sufficient to reach concrete conclusions.

Conclusions

In conclusion, our meta-analysis found significant increased CVD risk is associated with rs266729 and rs2241766, but not associated with rs1501299.

Electronic supplementary material

The online version of this article (10.1186/s12944-018-0767-8) contains supplementary material, which is available to authorized users.

Adiponectin and Its Isoforms in Pathophysiology

Adiponectin circulates in blood in multiple isoforms. High molecular weight (HMW) adiponectin is thought to be most biologically active and promotes glucose uptake, insulin sensitivity, and fatty acid oxidation. In obesity, adiponectin isoform formation is disrupted, leading to an inverse association between metabolic disease and HMW and total adiponectin. Adiponectin isoforms also function as acute-phase reactants influencing inflammation in acute and chronic disease. Interestingly, adiponectin and mortality have a U-shaped association. Unfortunately, data concerning adiponectin and its pathophysiologic function conflict. This is predominantly due to difficulties in adequate measurement of adiponectin isoforms and lack of a gold standard. In this review we provide a general overview of the formation and function of adiponectin and its isoforms under physiologic conditions. We highlight the ways adiponectin isoform formation is disrupted in obesity and its ensuing pathologic conditions. Furthermore, we will elaborate on the role of adiponectin isoforms as inflammatory proteins with respect to cardiac and kidney disease and discuss the association of adiponectin with mortality. Finally, we will provide a historical perspective on the measurement of adiponectin isoforms, current limitations, and future challenges.

Serum adiponectin levels predict acute coronary syndrome (ACS) in patients with severe carotid stenosis

As endocrine organ, adipose tissue may modulate inflammatory response by releasing a wide range of mediators, known as adipocytokines. Due to the complex balance between pro- and anti-inflammatory activity their pathophysiological and prognostic role in cardiovascular (CV) diseases still remains debated. Here, we consider the potential associations of circulating adipocytokines adiponectin, leptin and their ratio (LAR), with metabolic and inflammatory profiles in 217 patients with severe carotid stenosis. A prospective analysis investigating their predictive role toward acute coronary syndromes (ACS) was also drawn over a 12-month follow-up period. Serum leptin was positively associated with fasting insulinemia and HOMA-IR, but not with lipid profile and inflammation. Conversely, adiponectin was negatively associated with glucose, insulin, HOMA-IR, triglycerides and both systemic and intraplaque inflammatory markers whereas a positive association with high-density lipoprotein cholesterol (HDL-c) was observed. Accordingly, a significant association with metabolic profile was reported for LAR. According to the cut-off point identified by ROC curve, adiponectin values≤2.56μg/mL were correlated with a higher risk of ACS occurrence at 12months' follow-up (p-value for Log Rank test=0.0003). At Cox regression analysis the predictive ability of low serum adiponectin was confirmed also after adjustment for age, male gender and diabetes. In conclusion, adiponectin may be considered a biomarker of metabolic compensation, inversely associated with chronic low-grade inflammation. Circulating adiponectin is also associated with lower risk of adverse CV events in patients with severe carotid stenosis.

Genetic effects on hypertriglyceridemic waist phenotype: rs780094, rs10830963, rs151290, and rs972283 polymorphisms and the interactions between them and behavior risk factors

BACKGROUNDS

We aimed to evaluate the association of SNPs in GCKR, MTNR1B, KCNQ1, and KLF14 genes confirmed in previous studies and hapertriglyceridemic waist (HTGW) in Han Chinese, and assess the interactions between genes and behavior risk factors.

METHODS

We genotyped the single nucleotide polymorphisms (SNPs) for GCKR, MTNR1B, KCNQ1, and KLF14 gene were genotyped in 373 patients with HTGW and 466 normal healthy subjects. We used logistic regression to investigate the gene-gene, gene-behavior interactions for the risk of HTGW.

RESULTS

Among the 4 SNPs, the AG genotype of rs780094 was protective factor, whereas the recessive model of rs151290 was risk factor after adjusting for confounders. Stratified by sex, only for women, the recessive model of rs151290 was still significance. The significant synergies interactions between SNPs were found between rs780094 in GCKR and rs972283 in KLF14 and rs10830963 in MTNR1B, respectively; meanwhile, the antagonistic interaction was revealed for rs151290 and rs780094 only for women. For male, there were significant synergies interactions between rs780094, smoking and alcohol drinking; and antagonistic interaction was revealed between rs780094 and severe activity both for men and women.

CONCLUSIONS

GCKR and KLF14 genes play a significant role in risk of HTGW in a Han Chinese population.

Associations between two common single nucleotide polymorphisms (rs2241766 and rs1501299) of ADIPOQ gene and coronary artery disease in type 2 diabetic patients: a systematic review and meta-analysis

ADIPOQ gene polymorphisms were indicated to be associated with coronary artery disease (CAD) in diabetic patients, however, published studies reported inconsistent results. We performed this meta-analysis to reach a more accurate estimation of the relationship between two common ADIPOQ genetic polymorphisms (rs2241766 and rs1501299) and CAD risk in diabetic patients. Eligible studies were retrieved by searching PubMed, Embase, Wangfang, VIP database and China National Knowledge Infrastructure databases. Included and excluded criteria were formulated. The case group was diabetic patients with CAD, and the control group was diabetic subjects without CAD. Summary odds rations (ORs) and 95% confidence intervals (CIs) were used to evaluate ADIPOQ polymorphisms associations with CAD risk in diabetic group. Heterogeneity was evaluated by Q statistic and I² statistic. A total of twelve published articles, involving 3996 cases and 8876 controls were included in this meta-analysis. The pooled results from rs1501299 polymorphism showed decreased risk in homozygote model (TT VS GG: OR=0.67, 95%CI=0.54-0.83). Heterogeneity was detected in our study. Sensitivity analysis and subgroup analysis were conducted in the meta-analysis. For rs2241766 polymorphism, an increased risk was detected in Caucasian subgroup in heterozygote model (CT VS TT: OR=1.19, 95%CI=1.00-1.42). In genotyping method (PCR-RFLP) subgroup, an increased risk was found in recessive model (GG VS GT+TT: OR=2.05, 95%CI=1.23-3.39). In the sensitivity analysis of rs1501299, decreased risk was detected in allelic model (T VS G: OR=0.86, 95%CI=0.76-0.98) and recessive model (TT VS TG+GG: OR=0.47, 95%CI=0.33-0.67). Publication bias is not observed in our results. Our meta-analysis suggests that the rs1501299 polymorphism may play a protective role in CAD in diabetic patients. The rs2241766 polymorphism is found to be associated with a significant increase in CAD risk in Caucasian and genotyping method (PCR-RFLP) subgroups. Further studies are needed to confirm the prediagnostic effect of the two gene polymorphisms in CAD risk in diabetic patients.

Translating the biology of adipokines in atherosclerosis and cardiovascular diseases: Gaps and open questions

AIM

Critically discuss the available data, to identify the current gaps and to provide key concepts that will help clinicians in translating the biology of adipokines in the context of atherosclerosis and cardio-metabolic diseases.

DATA SYNTHESIS

Adipose tissue is nowadays recognized as an active endocrine organ, a function related to the ability to secrete adipokines (such as leptin and adiponectin) and pro-inflammatory cytokines (tumor necrosis factor alpha and resistin). Studies in vitro and in animal models have observed that obesity status presents a chronic low-grade inflammation as the consequence of the immune cells infiltrating the adipose tissue as well as adipocytes. This inflammatory signature is often related to the presence of cardiovascular diseases, including atherosclerosis and thrombosis. These links are less clear in humans, where the role of adipokines as prognostic marker and/or player in cardiovascular diseases is not as clear as that observed in experimental models. Moreover, plasma adipokine levels might reflect a condition of adipokine-resistance in which adipokine redundancy occurs. The investigation of the cardio-metabolic phenotype of carriers of single nucleotide polymorphisms affecting the levels or function of a specific adipokine might help determine their relevance in humans. Thus, the aim of the present review is to critically discuss the available data, identify the current gaps and provide key concepts that will help clinicians translate the biology of adipokines in the context of atherosclerosis and cardio-metabolic diseases.

Adiponectin and leptin gene polymorphisms in women with gestational diabetes mellitus

PURPOSE

Gestational diabetes mellitus (GDM) is the glucose intolerance occurring during pregnancy. The prevalence of GDM is increased in obese women. Leptin and adiponectin are adipokines that play an important role in the regulation of insulin secretion and glucose and lipid metabolism. The aim of this study was to examine the association between adiponectin and leptin gene polymorphisms and the development of GDM.

METHODS

This case-control study included 204 pregnant women with GDM and 207 pregnant women with normal glucose tolerance (NGT). The diagnosis of GDM was based on a 75-g oral glucose tolerance test (OGTT) at 24-28 weeks' gestation. To discriminate the ADIPOQ rs266729, rs1501299 and LEP rs2167270 alleles, TaqMan® Pre-Designed SNP Genotyping Assays were used.

RESULTS

There was a statistically significant association between the ADIPOQ rs266729 gene polymorphism and GDM. Among women with GDM, a higher prevalence of the G allele was observed (GG and CG genotypes). Multivariate logistic regression analysis, taking into account age, BMI before pregnancy, past pregnancies and the ADIPOQ rs266729 gene polymorphism, revealed that the presence of a G allele is an independent risk factor for GDM. Moreover, there was the association between the LEP rs2167270 polymorphism and the requirement for daily insulin, which was significantly higher in women with the A allele (AA and GA genotypes).

CONCLUSIONS

The results of our study suggest an association between adiponectin gene rs266729 as well as leptin gene rs2167270 polymorphisms and GDM.

Gene Polymorphisms of FABP2, ADIPOQ and ANP and Risk of Hypertriglyceridemia and Metabolic Syndrome in Afro-Caribbeans

OBJECTIVES

The metabolic syndrome (MetS) is a cluster of metabolic abnormalities and cardiovascular risk factors that are highly heritable and polygenic. We investigated the association of allelic variants of three candidate genes, rs1799883-FABP2, rs1501299-ADIPOQ and rs5065-ANP with MetS and its components, individually and in combination, using a genetic risk score.

METHODS

A cross-sectional study was conducted in 462 Afro-Caribbeans subjects without cardiovascular complications or lipid-lowering medications. Cardiovascular risk factors and MetS components (NCEP-ATPIII criteria) were recorded. The 3 SNPs were genotyped. The genetic risk score was calculated by summing the number of risk alleles at each locus. Logistic regressions were used.

RESULTS

Fifty-eight participants (12.6%) were diabetics and 116 (25.1%) had a MetS. In a dominant model, rs1799883 was associated with hypertriglyceridemia (OR 2.22; P = 0.014) and hypertriglyceridemic waist (HTGW), (P = 0.014) but not significantly with overweight (P = 0.049), abdominal obesity (P = 0.033) and MetS (P = 0.068). In a dominant model, the OR of MetS and HTGW for rs1501299 were 1.80 (P = 0.028) and 2.19 (P = 0.040) respectively. In a recessive model, the OR of hypertriglyceridemia for rs5065 was 1.94 (P = 0.075). The genetic risk score was significantly associated with MetS. Subjects carrying 4-5 risk alleles (18.8%) had a nearly 2.5-fold-increased risk of MetS compared to those carrying 0-1 risk allele (24.3%): OR 2.31; P = 0.025.

CONCLUSIONS

This study supports the association of FABP2, ANP and ADIPOQ gene variants with MetS or its components in Afro-Caribbeans and suggests a cumulative genetic influence of theses variants on this syndrome and a potential effect on lipid metabolism.

Association of Adiponectin Gene Polymorphisms With the Risk of Coronary Artery Disease in Patients With Nonalcoholic Fatty Liver Disease in a Chinese Han Population

BACKGROUND

Cardiovascular events are an independent risk factor for nonalcoholic fatty liver disease (NAFLD), which is the leading cause of mortality in NAFLD patients. Several recent studies demonstrated that adiponectin (Ad) polymorphisms were involved in the progression of NAFLD and coronary artery disease (CAD). However, reports on the association between Ad polymorphisms and the risk of developing CAD in NAFLD patients are lacking in a Northern Han Chinese population.

OBJECTIVES

The present study was designed to evaluate the association between Ad gene polymorphisms (rs266729 and rs2241766) and the risk of developing CAD in Northern Han Chinese patients with NAFLD.

MATERIALS AND METHODS

In this case-control study, using the polymerase chain reaction (PCR), Adrs266729 and rs2241766 gene polymorphisms were genotyped in B-type ultrasonography-proven NAFLD patients, with (n = 246) or without (n = 247) CAD and in healthy controls (n = 304). Serum lipid profiles were determined using biochemical methods. Statistical analyses were performed using SPSS 17.0 statistical software.

RESULTS

There were significant differences in the Adrs266729 G allele between the NAFLD patients with and without CAD (P < 0.05). In addition, there was a significant difference in the Adrs2241766 G allele of the NAFLD patients compared with that of the controls (P < 0.05). In the NAFLD CAD population, carriers of the G allele of Adrs266729 had higher serum triglycerides (TG), total cholesterol (TC), fasting plasma glucose (FPG), and low-density lipoprotein (LDL) levels and a lower Ad level than their noncarrier counterparts (P = 0.031, P = 0.034, P = 0.007, P < 0.001, and P < 0.001, respectively). NAFLD patients without CAD had higher TG and serum FPG values and a lower Ad level than their noncarrier counterparts (P = 0.014, P = 0.038, and P < 0.001, respectively). In the NAFLD patients with/without CAD, the carriers of the G allele of Adrs2241766 had higher TG levels (P = 0.039 and P = 0.042, respectively) than those of their noncarrier counterparts.

CONCLUSIONS

In this Northern Chinese Han population, the Adrs266729 and rs2241766 G alleles were closely associated with the occurrence of NAFLD. However, only NAFLD patients who carried the Adrs266729 G allele had an increased risk of developing CAD.

Genome- and epigenome-wide association study of hypertriglyceridemic waist in Mexican American families

BACKGROUND

There is growing interest in the hypertriglyceridemic waist (HTGW) phenotype, defined as high waist circumference (≥95 cm in males and ≥80 cm in females) combined with high serum triglyceride concentration (≥2.0 mmol/L in males and ≥1.5 mmol/L in females) as a marker of type 2 diabetes (T2D) and cardiovascular disease. However, the prevalence of this phenotype in high-risk populations, its association with T2D, and the genetic or epigenetic influences on HTGW are not well explored. Using data from large, extended families of Mexican Americans (a high-risk minority population in the USA) we aimed to: (1) estimate the prevalence of this phenotype, (2) test its association with T2D and related traits, and (3) dissect out the genetic and epigenetic associations with this phenotype using genome-wide and epigenome-wide studies, respectively.

RESULTS

Data for this study was from 850 Mexican American participants (representing 39 families) recruited under the ongoing San Antonio Family Heart Study, 26 % of these individuals had HTGW. This phenotype was significantly heritable (h (2) r = 0.52, p = 1.1 × 10(-5)) and independently associated with T2D as well as fasting glucose levels and insulin resistance. We conducted genome-wide association analyses using 759,809 single nucleotide polymorphisms (SNPs) and epigenome-wide association analyses using 457,331 CpG sites. There was no evidence of any SNP associated with HTGW at the genome-wide level but two CpG sites (cg00574958 and cg17058475) in CPT1A and one CpG site (cg06500161) in ABCG1 were significantly associated with HTGW and remained significant after adjusting for the closely related components of metabolic syndrome. CPT1A holds a cardinal position in the metabolism of long-chain fatty acids while ABCG1 plays a role in triglyceride metabolism.

CONCLUSIONS

Our results reemphasize the value of HTGW as a marker of T2D. This phenotype shows association with DNA methylation within CPT1A and ABCG1, genes involved in fatty acid and triglyceride metabolism. Our results underscore the importance of epigenetics in a clinically informative phenotype.

ADIPOQ -11377C>G Polymorphism Increases the Risk of Adipokine Abnormalities and Child Obesity Regardless of Dietary Intake

OBJECTIVE

The aim of the present study was to verify whether selected functional single nucleotide polymorphisms in LEP, LEPR, and ADIPOQ loci are associated with the development of obesity and serum levels of the respective adipokines in prepubertal white children with obesity.

METHODS

Frequencies of -2548G>A LEP (rs7799039), Q223R (rs1137101) and K656N (rs8129183) LEPR, and -11377C>G (rs266729) and -11426A>G (rs16861194) ADIPOQ polymorphisms were analyzed by restriction fragment length polymorphism in 101 obese (standard deviation score [SDS]-body mass index [BMI] >2) and 67 normal-weight (SDS-BMI <- 1 + 1 >) children. Serum adipokine concentrations were measured using the enzyme-linked immunosorbent assay method.

RESULTS

The GC/GG genotypes of -11377C>G ADIPOQ polymorphism were associated with a higher risk of obesity (P = 0.022, odds ratio 2.08 [95% confidence interval 1.11-3.90]). Individuals carrying the GG genotype had a higher leptin/total adiponectin ratio by 25% than CC homozygotes (P trend = 0.05). In the multivariate linear regression model, we found differences among particular genotypes of this polymorphism in concentrations of high molecular weight (HMW) adiponectin (P trend = 0.043) and HMW/total adiponectin ratio (P trend = 0.048), with the lowest values in GG homozygotes. Positive correlations between SDS-BMI and dietary reference intake percentage were observed in individuals homozygous for allele C (r = 0.403, P = 0.01) and CG heterozygotes (r = 0.428, P = 0.004). No significant correlations between both parameters were found in the GG homozygotes.

CONCLUSIONS

Among the analyzed polymorphisms, only -11377C>G ADIPOQ single nucleotide polymorphism was associated with obesity during the prepubertal period. Adipokine abnormalities coexisting with the lack of relations between SDS-BMI and dietary intake may predict a higher risk of future obesity-related disorders in obese children carrying the GG genotype than in those with other genotypes.

Genes, Genetics, and Environment in Type 2 Diabetes: Implication in Personalized Medicine

Type 2 diabetes (T2D) is a multifactorial anomaly involving 57 genes located on 16 different chromosomes and 136 single nucleotide polymorphisms (SNPs). Ten genes are located on chromosome 1, followed by seven genes on chromosome 11 and six genes on chromosomes 3. Remaining chromosomes harbor two to five genes. Significantly, chromosomes 13, 14, 16, 18, 21, 22, X, and Y do not have any associated diabetogenic gene. Genetic components have their own pathways encompassing insulin secretion, resistance, signaling, and β-cell dysfunction. Environmental factors include epigenetic changes, nutrition, intrauterine surroundings, and obesity. In addition, ethnicity plays a role in conferring susceptibility to T2D. This scenario poses a challenge toward the development of biomarker for quick disease diagnosis or for generating a consensus to delineate different categories of T2D patients. We believe, before prescribing a generic drug, detailed genotypic information with the background of ethnicity and environmental factors may be taken into consideration. This nonconventional approach is envisaged to be more robust in the context of personalized medicine and perhaps would cause lot less burden on the patient ensuring better management of T2D.

Adiponectin and leptin gene polymorphisms in patients with post-transplant diabetes mellitus

Background: Post-transplant diabetes mellitus (PTDM) is a common metabolic complication after organ transplantation and may be associated with the use of calcineurin inhibitors (tacrolimus and cyclosporine). Leptin and adiponectin are adipokines and play an important role in the regulation of insulin secretion as well as glucose and lipid metabolism. Aim: The aim of this study was to examine the association between adiponectin and leptin gene polymorphisms and development of PTDM. Materials & methods: The study included 323 patients who received kidney transplants and were treated with calcineurin inhibitors (tacrolimus or cyclosporine). Results: The association between adiponectin and leptin gene polymorphisms and PTDM was studied in three models of Cox regression analysis – additive, dominant and recessive. In these three models, the LEP rs2167270 gene polymorphism was statistically significantly associated with increased risk of PTDM. The association between the LEP rs2167270 polymorphism and PTDM was confirmed by multivariate regression analysis. Conclusion: The results of our study suggest an association between the leptin rs2167270 gene A allele and PTDM.

Original submitted 27 February 2015; Revision submitted 22 May 2015

Low-molecular-weight adiponectin is more closely associated with disease activity of rheumatoid arthritis than other adiponectin multimeric forms

Adiponectin is divided into high-molecular-weight (HMW), medium-molecular-weight (MMW), and low-molecular-weight (LMW) forms. These forms differ not only in the number of adiponectin molecules but also in their biological activity. There are conflicting findings regarding the role of adiponectin in rheumatoid arthritis (RA). Moreover, few reports have described the relationships between serum adiponectin multimers levels and RA. Therefore, we examined the association of total adiponectin and its multimers with RA. Two study groups were examined: 180 recently diagnosed untreated RA patients with disease duration less than 1 year (RA group) and 160 age- and sex-matched control subjects (control group). RA-related factors, blood pressure, body mass index, glucose, complete lipid profile, and adiponectin multimers were measured. The levels of total adiponectin and each multimer of adiponectin were significantly lower in the RA than in the control (P < 0.01). Serum levels of total, HMW, MMW, and LMW were positively correlated with triglycerides levels and negatively correlated with the Disease Activity Score for 28 joints (DAS28). Multivariate regression analysis showed that total, HMW, and MMW adiponectin were independently associated with serum triglycerides level. LMW adiponectin was independently correlated with serum triglycerides level and DAS28. The decreased LMW adiponectin levels may be associated with disease activity of RA.

Adiponectin gene variants, adiponectin isoforms and cardiometabolic risk in type 2 diabetic patients

AIMS/INTRODUCTION

The aim of the present study was to examine the associations of rs2241766 (+45T>G), rs1501299 (+276G>T), rs17300539 (-11391G>A) and rs182052 (-10069G>A) in the adiponectin (Ad) gene with adiponectin concentrations, and concomitantly the association of these variants with cardiometabolic risk in type 2 diabetic patients of African ancestry.

MATERIALS AND METHODS

A cross-sectional study of 200 patients was carried out. Concentrations of total, high (HMW), middle (MMW) and low (LMW) molecular weight adiponectin isoforms were measured. The four polymorphisms were genotyped.

RESULTS

Decreased values were noted for total Ad in overweight, dyslipidemia and coronary artery disease (CAD), for HMW in overweight and dyslipidemia, for MMW in CAD, for LMW in dyslipidemia and CAD, for the percentage HMW/total in overweight, and for MMW:HMW ratio in patients without hypertriglyceridemic waist (HTGW). Significant associations were noted between total Ad, HMW, and HMW/total Ad and rs182052 under a dominant model (P = 0.04, P = 0.03 and P = 0.04, respectively), and between MMW and rs17300539 (P = 0.006). No significant difference in adiponectin concentrations was noted according to rs2241766 and rs1501299 genotypes. Patients carrying the rs2241766 G allele (TG+GG) had an increased risk of HTGW (odds ratio [OR] 3.1; P = 0.04) and of CAD (OR 3.3; P = 0.01). The odds of having low total adiponectin concentrations (<25th percentile: 3.49 ng/mL) for carrying the rs182052A allele (AA+GA) was: OR 0.40; P = 0.009. The single-nucleotide polymorphism associated with adiponectin levels was not concomitantly associated with cardiometabolic risk factors.

CONCLUSIONS

Adiponectin concentrations and ADIPOQ variants are implicated in the pathophysiological process leading to cardiovascular diseases, but the genetic effects seem to be independent of adiponectin concentrations in our Afro-Caribbean diabetic patients.