Plasma adiponectin, T94G gene polymorphism and PAI-1 in patients with and without hypertension

Association of genetic variants in Leptin, leptin receptor and adiponectin with hypertension risk and circulating Leptin/Adiponectin changes

BACKGROUNDS

Hypertension is inheritable, and some candidate genes such as leptin and adiponectin have drawn special concerns.

OBJECTIVES

We performed a meta-analysis on the association of 7 genetic variants in genes encoding leptin, leptin receptor and adiponectin with hypertension risk and circulating leptin/adiponectin changes.

METHODS

Literature search, report selection and data extraction were performed by two authors independently. Effect sizes are expressed as odds ratio (OR) or standard mean difference (SMD) with 95% confidence interval (CI).

RESULTS

Total 32 reports (7432 cases with hypertension and 9218 controls) were meta-analyzed. Overall analyses indicated that rs7799039 (dominant model: OR = 1.67; 95 % CI: 1.03 to 2.71; P = 0.038) and (TTTC)_n (allelic model: OR = 1.53; 95 % CI: 1.05 to 2.23; P = 0.028) were significantly associated with hypertension risk. Subgroup analyses indicated that hypertension type, race, diabetes, genotyping method and quality score might be potential causes for between-study heterogeneity. Besides rs2241766, no evidence of publication bias existed for the other variants. Carriers of rs7799039-AG genotype had significantly higher leptin concentrations than carriers of rs7799039-GG genotype (SMD = 1.98; 95 % CI: 0.07 to 3.89; P = 0.042). In Mendelian randomization analyses, an increment of leptin concentrations by 1 ng/mL was causally associated with a 25 % significantly increased risk of hypertension (95 % CI: 1.02 to 10+; P < 0.05).

CONCLUSIONS

Our findings indicated that leptin gene rs7799039 and (TTTC)_n were potential hypertension-candidacy loci, and importantly high circulating leptin concentrations causally precipitated the development of hypertension.

Association between adiponectin T94G polymorphism and resistant hypertension in young-onset Taiwanese patients

Young-onset hypertensives (YOHs) with resistant hypertension (RH) have a greater long-term cardiovascular risk. The present study examined whether a functional adiponectin T94G polymorphism (rs2241766) is associated with RH in YOHs. We analyzed data from the Academia Sinica Collaborative Study on Hypertension Genetics in Taiwanese subjects to compare rs2241766 between YOHs with and without RH (≤50 years of age). RH was defined as the need for at least 3 drugs, including a diuretic to control blood pressure. Genotyping of rs2241766 was performed using TaqMan allelic discrimination. A total of 861 YOHs were enrolled and 54 had RH in enrolled population. For the rs2241766 in the allelic model, the odds ratio (OR) of RH allele frequency was 2.45 (p = 0.008), and there was a linear relationship between allele numbers and the presence of RH (p = 0.005). In multivariate analysis, the rs2241766 (OR = 2.766, p = 0.002), age (OR = 1.103, p = 0.001), uric acid (OR = 1.322, p = 0.001), high-sensitivity C-reactive protein (OR = 2.769, p = 0.001) and aldosterone (OR = 1.004, p = 0.001) were independently associated with the presence of RH. In the Taiwanese population, the adiponectin T94G polymorphism (rs2241766) is associated with RH in YOHs.

The association of two polymorphisms in adiponectin-encoding gene with hypertension risk and the changes of circulating adiponectin and blood pressure: A meta-analysis

Objectives

This meta-analysis was prepared to synthesize published data on the association of two polymorphisms (T45G and G276T) in adiponectin-encoding gene (ADIPOQ) with hypertension risk and the changes of circulating adiponectin and blood pressure.

Methodology and Major Findings

Data were collected and corrected by two authors, and were managed with Stata software. In total, 12 articles were synthesized, including 12 studies (3358 cases and 5121 controls) for the association of two study polymorphisms with hypertension risk and 11 studies (3053 subjects) for the between-genotype changes of adiponectin and/or blood pressure. Based on all qualified studies, the risk prediction for hypertension was nonsignificant for both polymorphisms, with significant heterogeneity for G276T polymorphism (I² = 53.8%). Overall changes in adiponectin and blood pressure were also nonsignificant for T45G, while contrastingly 276GT genotype was associated with significantly higher levels of adiponectin (weighted mean difference [WMD] = 0.72 μg/mL, 95% confidence interval [CI]: 0.04 to 1.41, P = 0.038), systolic (WMD = 5.15 mm Hg, 95% CI: 0.98 to 9.32, P = 0.016) and diastolic (WMD = 3.45 mm Hg, 95% CI: 0.37 to 6.53, P = 0.028) blood pressure with evident heterogeneity (I² = 72.0%, 78.3% and 80.0%, respectively), and these associations were more obvious in hypertensive patients. Publication bias was a low probability event for overall comparisons.

Conclusions

Our findings suggested that in spite of the nonsignificant association between ADIPOQ T45G or G276T polymorphism and hypertension, the heterozygous mutation of G276T was observed to account for increased levels of circulating adiponectin and blood pressure, especially in hypertensive patients.

Associations between polymorphisms of the ADIPOQ gene and hypertension risk: a systematic and meta-analysis

ADIPOQ gene polymorphisms have been indicated to be associated with hypertension; however, published studies have reported inconsistent results. Eligible studies were retrieved by searching the PubMed, Embase and China National Knowledge Infrastructure databases. The case group consisted of patients with hypertension, and the control group consisted of subjects with normal blood pressure. Based on eleven published articles, involving 4837 cases and 5618 controls, the pooled results from rs2241766 polymorphism showed increased risk in the allelic model (G VS T: OR = 1.16, 95%CI = 1.06–1.27), recessive model (GG VS GT + TT: OR = 1.34, 95%CI = 1.10–1.63), dominant model (GG + GT VS TT: OR = 1.15, 95%CI = 1.02–1.30) and homozygote model (GG VS TT: OR = 1.38, 95%CI = 1.21–1.69). In addition, rs266729 polymorphism showed increased risk for hypertension in the recessive model (GG VS GC + CC: OR = 1.43, 95%CI = 1.02–2.01). In the Caucasian subgroup, rs1501299 polymorphism showed decreased risk of hypertension in the allelic model (T VS G: OR = 0.75, 95%CI = 0.58–0.97), dominant model (TT + TG VS GG: OR = 0.83, 95%CI = 0.71–0.98) and heterozygote model (TG VS GG: OR = 0.82, 95%CI = 0.68–0.99). The rs2241766 polymorphism was associated with a significant increase in hypertension risk based on our analysis. Moreover, an increased risk of rs266729 in hypertension patients was also detected. Our meta-analysis suggests that the rs1501299 polymorphism may play a protective role in hypertension in Caucasian subgroup; however, this finding requires further study.

Common polymorphisms (rs2241766 and rs1501299) in the ADIPOQ gene are not associated with hypertension susceptibility among the Chinese

The ADIPOQ gene has been implicated in the etiology of hypertension. However, the results have been inconsistent. In this study, a meta-analysis was performed to assess the associations of ADIPOQ polymorphisms with hypertension risk among the Chinese. Published literature from PubMed, CNKI and Wanfang Data were retrieved. Pooled odds ratio (OR) with 95 % confidence interval (CI) was calculated using fixed- or random-effects model. Six studies (1,812 cases and 2,631 controls) for rs2241766 polymorphism and four studies (1,449 cases and 2,175 controls) for rs1501299 polymorphism were identified. A marginally significant association was observed for rs2241766 polymorphism under recessive genetic model (GG vs. GT+TT: OR = 1.22, 95 % CI 1.01-1.48) and for rs1501299 polymorphism under heterogeneous co-dominant model (TG vs. GG: OR = 0.86, 95 % CI 0.75-0.99) and dominant model (TT+TG vs. GG: OR = 0.85, 95 % CI 0.74-0.98). In addition, under other genetic models, there was no significant association for rs2241766 polymorphism (GG vs. TT: OR = 1.20, 95 % CI 0.98-1.48; GT vs. TT: OR = 0.97, 95 % CI 0.85-1.10; GG+GT vs. TT: OR = 1.01, 95 % CI 0.90-1.15) and for rs1501299 polymorphism (TT vs. GG: OR = 0.82, 95 % CI 0.62-1.08; TT vs. TG+GG: OR = 0.87, 95 % CI 0.66-1.14). However, the associations above were not robust by sensitivity analysis. The present meta-analysis indicated the limited evidence of the significant associations between ADIPOQ gene polymorphisms and hypertension susceptibility among the Chinese.

Genetic effects of adiponectin on blood lipids and blood pressure

OBJECTIVE

Results from the published studies on the association of adiponectin gene (ADIPOQ) polymorphisms with blood lipids and blood pressure are conflicting. We investigated the association of three ADIPOQ polymorphisms, +45 T > G (rs2241766), +276 G > T (rs1501299) and -11377 C > G (rs266729), with these traits in this meta-analysis.

RESEARCH DESIGN AND METHODS

We included 35 studies in this meta-analysis. Dominant models were used for this meta-analysis.

RESULTS

We did not detect a significant association of the -11377 C > G polymorphism with blood lipids or blood pressure (P > 0·05). The association of the +45 T > G polymorphism with blood lipids and blood pressure was, similarly, not significant (P > 0·05). The meta-analysis suggested a significant overall association of the +276 G > T polymorphism with lower levels of total cholesterol: weighted mean difference (WMD) = -0·10, 95% confidence interval (CI, -0·17, -0·03), P = 0·005, P(heterogeneity)  = 0·04. This association was marginally significant in East Asians and East Asians with type 2 diabetes: WMD = -0·10, 95% CI (-0·20, 0·00), P = 0·05, P(heterogeneity)  = 0·002, and WMD = -0·09, 95% CI (-0·18, -0·00), P = 0·05, P(heterogeneity)  = 0·80, respectively. After exclusion of a study that was the source of heterogeneity, the association was significant in overall populations and marginally significant in East Asians: WMD= -0·06, 95% CI (-0·11, -0·01), P = 0·01, P(heterogeneity)  = 0·98, and WMD = -0·06, 95% CI (-0·12, 0·00), P = 0·07, P(heterogeneity)  = 0·83, respectively. However, none of these associations were significant after Bonferroni correction (significant threshold: P < 0·003).

CONCLUSIONS

Our meta-analysis does not suggest any association of the three ADIPOQ polymorphisms with blood lipids and blood pressure.

Association analysis of ADPRT1, AKR1B1, RAGE, GFPT2 and PAI-1 gene polymorphisms with chronic renal insufficiency among Asian Indians with type-2 diabetes

BACKGROUND

To determine association of nine single nucleotide polymorphisms (SNPs) in ADP ribosyltransferase-1 (ADPRT1), aldo-keto reductase family 1 member B1 (AKR1B1), receptor for advanced glycation end-products (RAGE), glutamine:fructose-6-phosphate amidotransferase-2 (GFPT2), and plasminogen activator inhibitor-1 (PAI-1) genes with chronic renal insufficiency (CRI) among Asian Indians with type 2 diabetes; and to identify epistatic interactionss between genes from the present study and those from renin-angiotensin-aldosterone system (RAAS), and chemokine-cytokine, dopaminergic and oxidative stress pathways (previously investigated using the same sample set).

METHODS

Type 2 diabetes subjects with CRI (serum creatinine > or =3.0 mg/dl) constituted the cases (n = 196), and ethnicity and age matched individuals with diabetes for a duration of > or = 10 years, normal renal functions and normoalbuminuria recruited as controls (n = 225). Allelic and genotypic constitution of 10 polymorphisms (SNPs) from five genes namely--ADPRT1, AKR1B1, RAGE, GFPT2 and PAI-1 with diabetic CRI was investigated. The genetic associations were evaluated by computation of odds ratio and 95% confidence interval. Multiple logistic regression analysis was carried out to correlate various clinical parameters with genotypes, and to study epistatic interactions between SNPs in different genes.

RESULTS

Single nucleotide polymorphisms -429 T>C in RAGE and rs7725 C>T SNP in 3' UTR in GFPT2 gene showed a trend towards association with diabetic CRI. Investigation using miRBase statistical tool revealed that rs7725 in GFPT2 was a perfect target for predicted miRNA (hsa miR-378) suggesting the presence of the variant 'T' allele may result in an upregulation of GFPT2 contributing to diabetic renal complication. Epistatic interaction between SNPs in transforming growth factor TGF-beta1 (investigated using the same sample set and reported elsewhere) and GFPT2 genotype was observed.

CONCLUSIONS

Association of SNPs in RAGE and GFPT2 suggest that the genes involved in modulation of oxidative pathway could be major contributor to diabetic chronic renal insufficiency. In addition, GFPT2 mediated overproduction of TGF-beta1 leading to endothelial expansion and thereby CRI seems likely, suggested by our observation of a significant interaction between GFPT2 with TGF-beta1 genes. Further, identification of predicted miRNA targets spanning the associated SNP in GFPT2 implicates the rs7725 SNP in transcriptional regulation of the gene, and suggests GFPT2 could be a relevant target for pharmacological intervention. Larger replication studies are needed to confirm these observations.