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

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.

Role of Adiponectin in Cardiovascular Diseases Related to Glucose and Lipid Metabolism Disorders

Lifestyle changes have led to increased incidence of cardiovascular disease (CVD); therefore, potential targets against CVD should be explored to mitigate its risks. Adiponectin (APN), an adipokine secreted by adipose tissue, has numerous beneficial effects against CVD related to glucose and lipid metabolism disorders, including regulation of glucose and lipid metabolism, increasing insulin sensitivity, reduction of oxidative stress and inflammation, protection of myocardial cells, and improvement in endothelial cell function. These effects demonstrate the anti-atherosclerotic and antihypertensive properties of APN, which could aid in improving myocardial hypertrophy, and reducing myocardial ischemia/reperfusion (MI/R) injury and myocardial infarction. APN can also be used for diagnosing and predicting heart failure. This review summarizes and discusses the role of APN in the treatment of CVD related to glucose and lipid metabolism disorders, and explores future APN research directions and clinical application prospects. Future studies should elucidate the signaling pathway network of APN cardiovascular protective effects, which will facilitate clinical trials targeting APN for CVD treatment in a clinical setting.

Polymorphism in Adiponectin and Adiponectin Receptor Genes in Diabetes Mellitus Pathogenesis

The role played by hereditary factors in the development of diabetes mellitus type 2 (DM2) has not yet been fully established. Therefore, the purpose of our study was to investigate the prevalence of adiponectin and polymorphism in its gene receptors in connection with the primary symptoms of DM2 pathogenesis. Genomic DNA was isolated from the whole blood of 94 patients with an established diagnosis of DM2 using the phenol–chloroform method. Gene polymorphisms were determined using real-time polymerase chain reaction (PCR). The most common polymorphic variants in patients with DM2 were the genotypes AA (rs11061971) and GG (rs16928751) on the ADIPOR2 gene. A strong correlation was found between the rs16928751 polymorphism on the ADIPOR2 gene and increased body mass index (BMI). TG (rs2275737) ADIPOR1 gene genotype carriers were found to have the highest levels of glycosylated hemoglobin (HbA1), whereas TT (rs2275738) caused stable hyperglycemia. In addition, the rs16928751 ADIPOR2 gene polymorphism showed an association with the development of key mechanisms of DM2 in the Russian population, although a number of genomic searches failed to show any association of this gene with DM2. Unique gene variants associated with the risk of developing DM2 in the Crimean population were established.

Genetic and pathophysiological substantiation of polyphenolic grape processing products’ application in the treatment of metabolic syndrome in the population of the Republic of Crimea

Adipose tissue in abdominal obesity produces various cytokines, the most important of which is adiponectin (AN). Polymorphism of the AN receptor genes is associated with the risk of metabolic syndrome (MS) and type 2 diabetes mellitus (DM2) development. The aim of the study was to investigate the association of AN genes receptors’ polymorphism with the development of MS and DM2 in the Republic of Crimea as well as the possibility of named pathology correction with polyphenolic functional foods. The study included 100 patients with confirmed diagnosis of DM2 and MS. Genomic DNA was isolated from the whole blood of patients. Gene polymorphism amplification was performed by PCR real-time. The most common genotype of the ADIPOQ gene (rs1501299) among patients with DM2 and MS was GT polymorphism G276T. The most frequent genotypes of the ADIPOR1 gene were AC (rs2275737) – 53.3% and CT (rs2275738) - 50.0%. The most frequent combinations between ADIPOR1 and ADIPOQ genes were AC (rs2275737) /CT (rs2275738) and GT (rs1501299) – 28.6%, as well as AC (rs2275737)/CT (rs2275738) and GG (rs1501299) – 19.7%. Thus, in patients with MS and DM2 in the Republic of Crimea, associations of polymorphism of the genes of the AN receptors with the development of this pathology have been established. It is known that polyphenols of red grape varieties are epigenetic modifiers. Therefore, these products can be included in individual nutrition programs in population groups genetically predisposed to MS and DM2.

G276T polymorphism in the ADIPOQ gene is associated with a reduced risk of polycystic ovarian syndrome: A meta-analysis of Asian population

OBJECTIVE

The etiology of polycystic ovarian syndrome (PCOS) has not yet been fully explained. Several studies suggested an association between two single nucleotide polymorphisms (T45G and G276T) of the ADIPOQ gene that encodes for the hormone adiponectin and PCOS susceptibility. Hence, we performed a meta-analysis to investigate the relationship of the two further.

MATERIALS AND METHODS

Literature search was conducted in PubMed up to June 22, 2018, for related publications written in English. Selected data were extracted from the included studies and was subjected to analysis using Review Manager 5.3. Odds ratios (ORs) and 95% confidence intervals (CIs) were computed and pooled from the resulting studies. Subgroup analysis by ethnicity was also performed.

RESULTS

Overall analysis showed that women with the G276T polymorphism have reduced susceptibility to PCOS (OR: 0.68; 95% CI: 0.60-0.78; P^A < 0.001). While no significant association was observed for the T45G polymorphism (OR: 1.07; 95% CI: 0.93-1.24; P^A = 0.34). Subgroup analysis, on the other hand, showed significant associations among East Asians (OR: 0.69; 95% CI: 0.57-0.82; P^A < 0.001) for the G276T association.

CONCLUSION

Results of this meta-analysis suggests that women with the G276T polymorphism are less likely to develop PCOS. However, more studies are needed to confirm the claims of this meta-analysis.

Glycated hemoglobin correlates with arterial stiffness and endothelial dysfunction in patients with resistant hypertension and uncontrolled diabetes mellitus

This study aimed to evaluate the effects of glycated hemoglobin (HbA_1c ) on flow-mediated dilation, intima-media thickness, pulse wave velocity, and left ventricular mass index in patients with resistant hypertension (RHTN) comparing RHTN-controlled diabetes mellitus and RHTN-uncontrolled type 2 diabetes mellitus. Two groups were formed: HbA_1c <7.0% (RHTN-controlled diabetes mellitus: n = 98) and HbA_1c ≥7.0% (RHTN-uncontrolled diabetes mellitus: n = 122). Intima-media thickness and flow-mediated dilation were measured by high-resolution ultrasound, left ventricular mass index by echocardiography, and arterial stiffness by carotid-femoral pulse wave velocity. No differences in blood pressure levels were found between the groups but body mass index was higher in patients with RHTN-uncontrolled diabetes mellitus. Endothelial dysfunction and arterial stiffness were worse in patients with RHTN-uncontrolled diabetes mellitus. Intima-media thickness and left ventricular mass index measurements were similar between the groups. After adjustments, multiple linear regression analyses showed that HbA_1c was an independent predictor of flow-mediated dilation and pulse wave velocity in all patients with RHTN. In conclusion, HbA_1c may predict the grade of arterial stiffness and endothelial dysfunction in patients with RHTN, and superimposed uncontrolled diabetes mellitus implicates further impairment of vascular function.

Adiponectin gene polymorphisms and obesity increase the susceptibility to arsenic-related renal cell carcinoma

Our recent study found that high urinary total arsenic levels were associated with renal cell carcinoma (RCC). Recent studies demonstrated that low circulating adiponectin was related to RCC. The aim of the present study was to explore the relationship between adiponectin gene (ADIPOQ) polymorphisms and RCC and investigate whether individuals with an ADIPOQ risk genotype, obesity, and high urinary total arsenic levels have a modified odds ratio (OR) of RCC. A total of 389 RCC patients and 389 age- and sex-matched controls were recruited between November 2006 and December 2012 in Taiwan. Image-guided biopsy or surgical resection of renal tumors was performed to pathologically verify RCC. Genomic DNA was used to examine the genotypes of the ADIPOQ rs182052, ADIPOQ rs2241766, ADIPOQ rs1501299, and ADIPOQ rs1063539 SNPs by PCR-RFLP. HPLC-HG-AAS was used to measure the concentrations of urinary arsenic species. Participants with the ADIPOQ rs182052 G/A+A/A genotype had a significantly higher OR of RCC compared with those with the ADIPOQ rs182052 G/G genotype. The OR (95% confidence interval [CI]) was 1.70 (1.23-2.36). The OR of RCC for the combined effect of high urinary total arsenic levels and obesity, which was dose-dependent, in individuals with the ADIPOQ rs182052 G/A+A/A genotype was 9.33 (3.85-22.62). The present study found significant combined effects of obesity and the ADIPOQ rs182052 G/A+A/A genotype on the arsenic-related risk of RCC in a population with low arsenic exposure. Arsenic exposure, obesity, and the ADIPOQ rs182052 polymorphism could be predictors of a higher OR of RCC.