Associations between single-nucleotide polymorphisms (+45T>G, +276G>T, -11377C>G, -11391G>A) of adiponectin gene and type 2 diabetes mellitus: a systematic review and meta-analysis

Association between adiponectin single nucleotide polymorphisms and the risk of diabetic polyneuropathy

Genetic factors play a significant role in the occurrence and clinical course of diabetic peripheral neuropathy (DPN). This research aimed to search the influence of adiponectin single nucleotide polymorphisms (SNPs) on the risk of developing and the severity of DPN in Egyptian patients. Adiponectin SNPs were genotype in 360 participants comprising diabetic sufferers with and without peripheral neuropathy and healthy volunteers via the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) approach. Regarding the + 45 T/G SNP, the TG/ and GG genotypes and the G allele were linked to an rised risk of DPN by comparing the DPN group with both the control and diabetic patients without peripheral neuropathy (DWPN) groups, and when comparing the DWPN group with the control group. Concerning + 276 G/T SNP, the GT genotype and T allele were linked to a declined risk of occuring DPN when comparing the DPN group with both other groups. Patients with DPN had greater frequencies of the GA genotype of the - 11,391 G/A SNP than individuals in the control group, while patients with DPN had greater frequencies of the AA genotype than patients in the DWPN group. Regarding clinic-pathological features, a meaningful rise in the mean values of fasting blood glucose (FBG), duration of the disease, and Toronto Clinical Neuropathy Severity Score (TCSS) were noted in the + 45 GG genotype and G allele carriers. Contrariwise, the + 276 TT genotype carriers had lower mean values for the same clinic-pathological features. For the T allele carriers, the same results were observed in case of duration of the disease and TCSS value. Our results concluded that adiponectin + 45 T/G SNP could be a risk factor considering DPN and the severity of the disease. The - 11391G/A SNP might be associated with DPN. In addition, + 276 G/T SNP could be a protective factor regarding DPN and the severity of the disease.

Association of adiponectin gene single nucleotide polymorphisms with environmental risk factors in type 2 diabetes mellitus: An updated evidence of haplotype-based analysis study

BACKGROUND AND AIM

Adiponectin (ADIPOQ) gene is considered to be one of the promising players in deciphering the genetic bases of type 2 diabetes. This study investigated the associations between haplotype combinations of three single nucleotide polymorphisms (SNPs) of the ADIPOQ gene and two SNPs of the adiponectin receptor 1 (AdipoR1) and 2 (AdipoR2) genes with environmental risk factors for the prediction of T2DM disorder susceptibility in the Iranian population.

METHODS

This case-control and cross-sectional study was conducted on 182 patients with T2DM and 155 healthy controls. Genotyping was performed using amplification refractory mutation system-PCR (ARMS-PCR) for rs17300539G/A, rs2241766T/G, and rs1501299G/T of the ADIPOQ gene, rs1342387C/T of the AdipoR1 gene, and rs10773989T/C of the AdipoR2 gene.

RESULTS

All polymorphisms met the Hardy-Weinberg equilibrium (p> 0.05). The studied SNPs; rs17300539, rs2241766 of the ADIPOQ gene and rs10773989 of the AdipoR2 gene, were significantly associated with an increased risk of T2DM. Two-way ANOVA analysis indicated that GG carriers of rs2241766T/G had a significantly lower waist-to-hip ratio (P= 0.049) and body mass index (P= 0.011) and higher HbA1c (P= 0.048) compared to TT carriers, while TT genotype carriers of rs2241766T/G showed the higher plasma adiponectin concentration compared to TG and GG carriers (P= 0.009 and P= 0.013, respectively). CC carriers of rs10773989T/C displayed a significantly higher LDL level compared to the TT genotype carries (P= 0.036). Also plasma adiponectin concentrations were significantly lower in AA genotype carriers of rs17300539G/A compared to GG and GA genotypes carriers in the control group only (P= 0.005 and P= 0.016, respectively). According to Combined Haplotype ([rs17300539, rs2241766, rs1501299]/[rs17300539, rs2241766, rs1501299]) analysis, GTT-homozygote carriers displayed the highest plasma adiponectin concentration and in contrast, GGG/GTG, ATG/GTG, and GGG/GGG showed the lowest plasma adiponectin concentration in the controls (p> 0.05).

CONCLUSION

The adiponectin gene haplotype combinations were associated with plasma adiponectin concentration in healthy individuals. In T2DM, adiponectin genetic variants displayed less effect on adiponectin plasma concentration.

Association study between adiponectin gene variants, serum levels and the risk of type 2 diabetes in Tunisian women: Insights from BMI stratification

Although prior studies have shown that adiponectin synthesis is genetically determined and that its levels influence susceptibility to T2D, the results in this regard have been inconsistent. This study aims, to investigate the relationship between adiponectin gene variants with the risk of developing T2D among Tunisian women and in relation to their BMI status. A cohort of 491 Tunisian T2D women and 373 non-diabetic subjects participated in the study. Nine ADIPOQ variants namely rs16861194, rs17300539, rs266729, rs822395, rs822396, rs2241766, rs1501299, rs2241767 and rs3774261 were selected and genotyped using the TaqMan® SNP genotyping assay. Fasting serum adiponectin levels were quantified using ELISA. The results showed that only the rs17300539 variant exhibited a significant association with the risk of T2D. However, upon considering T2D group stratification based on BMI (normal weight [18-24.99 Kg/m2], overweight [25-29.99 Kg/m2] and obese [30-34.99 Kg/m2]), the ADIPOQ rs2241766 variant emerged as a contributing risk factor for increased BMI in obese women with T2D. Linear regression analysis revealed that the minor allele (A), (GA) and (AA) genotypes of rs17300539 as well as the (G) allele and (GG) genotype of rs2241766 were significantly associated with hypoadiponectinemia in T2D subjects. Two haplotypes namely GGCAATGAA and AGCCGTGGA, were identified as conferring a higher risk of T2D with the GGCAATGAA haplotype also correlating with hypoadiponectinemia. Our study underscores the importance of the rs17300539 variant and the GGCAATGAA haplotype in the risk of T2D and hypoadiponectinemia. Additionally, the presence of the rs2241766 variant highlights its association with 'diabesity' and hypoadiponectinemia among Tunisian T2D women.

Association of ADIPOQ Gene Polymorphisms with Type 2 Diabetes and Obesity Risk in the Kazakh Population: A Case-Control and Population-Based Study

Type 2 diabetes mellitus (T2DM) is a socially significant disease with increasing prevalence worldwide. It is characterized by heterogeneous metabolic disorders and is associated with various risk factors, including BMI, abnormal lipid levels, hypertension, smoking, dietary preferences, physical inactivity, sedentary lifestyle, family history of diabetes, prediabetes or gestational diabetes, inflammation, intrauterine environment, age, sex, ethnicity, and socioeconomic status. Assessing the genetic risk of developing T2DM in specific populations remains relevant. The ADIPOQ gene, encoding adiponectin, is directly related to the risk of developing T2DM, obesity, and cardiovascular diseases. Our study demonstrated significant associations of ADIPOQ gene polymorphisms with the risk of developing T2DM and obesity, as well as with fasting glucose levels and BMI, in the Kazakh population. Specifically, rs266729 was significantly associated with T2DM and obesity in the Kazakh population, while other studied polymorphisms (rs1501299, rs2241766, and rs17846866) did not show a significant association. These findings suggest that ADIPOQ gene polymorphisms may influence T2DM risk factors and highlight the importance of genetic factors in T2DM development. However, further research in larger cohorts is needed to confirm these associations.

LEP (G2548A-G19A) and ADIPOQ (T45G-G276T) gene polymorphisms are associated with markers for metabolic syndrome

BACKGROUND AND AIMS

There is a link between genetics with metabolic balance and adiposity homeostasis on metabolic syndrome (MetS). Polymorphism in adipokine genes such as leptin and adiponectin may play an important role in its development. This study aimed to determine the association of the individual and general components of MetS with genetic alterations in LEP (rs7799039 and rs2167270) and ADIPOQ (rs1501299 and rs2241766) genes in the Mexican population.

METHODS AND RESULTS

The polymorphisms of the LEP gene rs7799039 and rs2167270, together with rs1501299 and rs2241766 polymorphisms of the ADIPOQ gene were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) on 328 individuals (n = 131 MetS). The rs7799039 under the recessive inheritance model was found to be associated with increased risk of MetS (OR = 2.16, 95% CI = 1.06-4.37), dyslipidemia (OR = 7.97, 95% CI = 2.17-29.36), low HDL (OR = 7.01, 95% CI = 1.65-29.71) and hypertension (OR = 13.02, 95% CI = 1.76-96.44); the heterozygote demonstrate a protective effect on MetS (OR = 0.48, 95% CI = 0.28-0.88) and diabetes (OR = 0.09, 95% CI = 0.02-0.53) under the over the dominant model. Haplotype analysis showed linkage disequilibrium between the SNPs of ADIPOQ rs1501299/rs2241766, and their association as risk factors for low HDL and hypertension.

CONCLUSION

The association of rs7799039 with the presence of MetS, suggests a risk factor for the development of dyslipidemia, as well as its heterozygous as a protective factor for DM. There is a linkage disequilibrium between the SNPs of ADIPOQ.

Adiponectin: A Promising Target for the Treatment of Diabetes and Its Complications

Diabetes mellitus, a chronic metabolic disorder characterized by hyperglycemia, presents a formidable global health challenge with its associated complications. Adiponectin, an adipocyte-derived hormone, has emerged as a significant player in glucose metabolism and insulin sensitivity. Beyond its metabolic effects, adiponectin exerts anti-inflammatory, anti-oxidative, and vasoprotective properties, making it an appealing therapeutic target for mitigating diabetic complications. The molecular mechanisms by which adiponectin impacts critical pathways implicated in diabetic nephropathy, retinopathy, neuropathy, and cardiovascular problems are thoroughly examined in this study. In addition, we explore possible treatment options for increasing adiponectin levels or improving its downstream signaling. The multifaceted protective roles of adiponectin in diabetic complications suggest its potential as a novel therapeutic avenue. However, further translational studies and clinical trials are warranted to fully harness the therapeutic potential of adiponectin in the management of diabetic complications. This review highlights adiponectin as a promising target for the treatment of diverse diabetic complications and encourages continued research in this pivotal area of diabetes therapeutics.

ADIPOQ gene (T45G and G276T) single nucleotide polymorphisms and their association with gestational diabetes mellitus in a Filipino population

Several studies have associated the presence of ADIPOQ gene polymorphisms with insulin resistance, adiponectin levels, and metabolic diseases such as diabetes, although with varying degrees of correlation depending on ethnicity. Here we aim to identify individual's susceptibility to gestational diabetes mellitus (GDM) in the presence of T45G and G276T single nucleotide polymorphisms (SNPs) within the ADIPOQ gene among Filipino pregnant women. A total of 285 pregnant women (95 GDM cases and 190 controls) were included in this study. Two ADIPOQ gene polymorphisms were genotyped using TaqMan assay. Results of SNP genotyping showed no significant differences in the frequencies of TT, TG and GG genotypes of T45G SNP between the GDM and control group [p = 1.0000, 0.6179, 0.5797; OR (95%CI) = 1.030 (0.582-1.874), 1.135 (0.683-1.828), 0.833 (0.481-1.420)]. Similarly, the frequencies of GG, GT, and TT genotypes of G276T SNP were comparable in both groups [p = 0.8002, 1.0000, 0.3466; OR (95%CI) = 1.090 (0.654-1.785), 1.022 (0.616-1.665), 0.433 (0.092-1.698)]. Moreover, although adiponectin levels were significantly decreased in GDM group (p = 0.0196) and have shown substantial negative correlations with FBS, 1-hour OGTT, 2-hour OGTT, and HOMA-IR (p < 0.05), they were not significantly different according to genotypes of T45G and G276T polymorphisms both in GDM and control group. Our results suggest that neither of the two ADIPOQ gene polymorphisms influence adiponectin levels and development of GDM in a Filipino population.

Association of Adiponectin 45T/G (rs2241766) and Visfatin 4689G/T (rs2110385) Gene Polymorphisms with Susceptibility to Obesity

Background

This study aimed to see whether the adiponectin 45T/G (rs2241766) and visfatin 4689G/T (rs2110385) gene polymorphisms in an Iranian population are linked to obesity and/or obesity-related traits in normal and obese individuals.

Methods

230 obese individuals and 169 healthy controls had their genomic DNA taken. The alleles and genotypes of the rs2241766 and rs2110385 polymorphisms were determined using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique.

Results

Obese individuals had considerably greater frequencies of the G allele and GG genotypes of the rs2241766 polymorphism than healthy controls (35% vs 21%, Probability (P) <0.0001, odds ratios (OR): 1.99, 95% confidence intervals (CI): 1.45-2.75 and 21% vs 7%, P = 0.002, OR: 3.52, 95% CI: 1.81-6.85, respectively). In comparison to healthy controls, obesity patients had substantially lower frequencies of the T allele and TT genotype of the rs2241766 polymorphism (65% vs 79%, P < 0.0001, OR: 0.50, 95% CI: 0.36-0.69 and 51% vs 65%, P = 0.008, OR: 0.58, 95% CI: 0.39-0.87, respectively). Obese individuals had substantially higher frequencies of the G allele and GG genotype in the rs2110385 polymorphism than healthy controls (77% vs 69%, P = 0.01, OR: 1.47, 95% CI: 1.07-2.0 and 61% versus 51%, P = 0.047, OR: 1.5, 95% CI: 1.0-2.2, respectively). When compared to healthy controls, the frequency of the T allele in the rs2110385 polymorphism was considerably lower in obese individuals (23% vs 31%, P = 0.01, OR: 0.68, 95% CI: 0.5-0.93). Furthermore, these single nucleotide polymorphisms (SNPs) were shown to have a strong link to clinical data in obese individuals. In the case of adiponectin, 45T/G (rs2241766) genotypes, serum low-density lipoprotein, waist circumference, and diastolic blood pressure were substantially different among the rs2241766 genotypes (P = 0.007, P = 0.000, and P = 0.011, respectively). In the instance of the visfatin 4689G/T (rs2110385) gene polymorphism, serum triglycerides was substantially different among the rs2110385 genotypes (P = 0.039).

Conclusions

In the Iranian population, our findings revealed a strong link between adiponectin and visfatin gene polymorphisms and obesity and several obesity-related clinical characteristics. These SNPs might be used to identify those who are at risk of becoming obese.

Novel single nucleotide polymorphisms in gestational diabetes mellitus

The association between gestational diabetes mellitus (GDM) and single nucleotide polymorphisms (SNPs) has attracted global research attention. Exploring SNPs can help us further understand the pathogenesis of GDM, predict the risk of GDM, and guide the management of GDM patients. In this review, we summarized the studies on the association between SNPs and GDM, focusing on novel SNPs published in the last 10 years. The SNPs identified to be associated with GDM included HMG20A (rs7178572), CDKAL1 (rs7756992, rs7754840, and rs7747752), ADIPOQ (rs266729 and rs17300539), MTHFR (rs1801133), IL10 (rs3021094), CDKN2B (rs1063192), and TRPM5 (rs35197079). However, the role of SNPs in the prediction, diagnosis, treatment, and prognosis of GDM, as a polygenic disease, needs to be further explored in multiple ethnic populations.

A Meta-analysis of ADIPOQ rs2241766 polymorphism association with type 2 diabetes

Objective

There is extensive research on the association between polymorphisms in the adiponectin gene (ADIPOQ) and type 2 diabetes (T2D). The present meta-analytic study explored the association between ADIPOQ rs2241766 polymorphisms and T2D.

Metolds

Articles were collected by searching Google Scholar, Scopus, and PubMed electronic databases until 2021. They were searched using a systematic search of original and sensitive English keywords and their equivalent keywords based on the keywords "type 2 diabetes", "ADIPOQ", and "rs2241766". The article selection criteria were based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) flow diagram.

Results

The results revealed that there was no bias in this study. Some studies, such as Joshaghani et al. (odds ratio [OR] = 2.18), Hussain et al. (OR = 2.12), Momin (OR = 4.45), and Amal et al. (OR = 1.84), showed an increasing effect of ADIPOQ rs266729 polymorphism on T2D with 95% CI (P ˂ 0.01), while some have shown no significant association between them.

Conclusion

The results of this meta-analytic study showed the relationship between ADIPOQ and rs2241766. Also, it was found that Rs2241766 polymorphism and allele increase the risk, and rs2241766 increases the risk of developing T2D (OR = 1.29).

Association of ADIPOQ Single-Nucleotide Polymorphisms with the Two Clinical Phenotypes Type 2 Diabetes Mellitus and Metabolic Syndrome in a Kinh Vietnamese Population

PURPOSE

Genetic factors play an important role in the development of type 2 diabetes mellitus (T2DM) and metabolic syndrome (MetS). However, few genetic association studies related to these disorders have been performed with Vietnamese subjects. In this study, the potential associations of ADIPOQ single nucleotide polymorphisms (SNPs) with T2DM and MetS in a Kinh Vietnamese population were investigated.

PATIENTS AND METHODS

A study with 768 subjects was conducted to examine the associations of four ADIPOQ SNPs (rs266729, rs1501299, rs3774261, and rs822393) primarily with T2DM and secondarily with MetS. The TaqMan SNP genotyping assay was used to determine genotypes from subjects' DNA samples.

RESULTS

After statistical adjustment for age, sex, and body mass index, the ADIPOQ SNP rs266729 was found to be associated with increased risk of T2DM under multiple inheritance models: codominant (OR = 2.30, 95% CI = 1.16-4.58), recessive (OR = 2.17, 95% CI = 1.11-4.26), and log-additive (OR = 1.32, 95% CI = 1.02-1.70). However, rs1501299, rs3774261, and rs822393 were not associated with risk for T2DM. Additionally, rs266729, rs3774261, and rs822393 were statistically associated with MetS, while rs1501299 was not. Haplotype analysis showed a strong linkage disequilibrium between the SNP pairs rs266729/rs822393 and rs1501299/rs3774261, and the haplotype rs266729(G)/rs822393(T) was not statistically associated with MetS.

CONCLUSION

The results show that rs266729 is a lead candidate SNP associated with increased risk of developing T2DM and MetS in a Kinh Vietnamese population, while rs3774261 is associated with MetS only. Further functional characterization is needed to uncover the mechanism underlying the potential genotype-phenotype associations.

Adiponectin Gene Polymorphism (rs17300539) Has No Influence on the Occurrence of Metabolic Syndrome in Women with Polycystic Ovary Syndrome

Adiponectin (rs17300539) is implicated in the pathogenesis of metabolic syndrome (MS), a common comorbidity of polycystic ovarian syndrome (PCOS). The aim of this study was to analyze the association between adiponectin gene polymorphism and incidence of MS in patients with PCOS. The study included 201 women (age 18 to 35 years), among them 81 patients with PCOS without concomitant MS, 70 subjects with PCOS and concomitant, and 50 regularly menstruating controls. Adiponectin gene polymorphism (11391 G/A, rs17300539) was determined by means of a real-time PCR. The study groups did not differ significantly in terms of their age and frequencies of various genotypes of the adiponectin gene polymorphism. The largest proportion in the whole group was Caucasian women (n = 178, 88.56%), who carried the GG genotype of the polymorphism; frequencies of GA and AA genotypes in the whole study group were 10.94% (n = 22) and 0.5% (n = 1), respectively. The presence of G or A allele of the rs17300539 adiponectin gene polymorphism was not associated with a greater likelihood of PCOS with/without concomitant MS. The hereby presented findings imply that MS is a common comorbidity in women with PCOS. However, the incidence of concomitant MS does not seem to be associated with adiponectin gene polymorphism.

Adiponectin gene polymorphisms and risk of type 2 diabetes: an updated evidence for meta-analysis

BACKGROUND

Growing body of evidence suggest the association between SNP - 11377 C > G and SNP + 276 G > T polymorphisms of adiponectin gene with type 2 diabetes (T2D). However, these findings have not been conclusive and consistent. The present study quantitatively evaluates the data on the association between DIPOQ - 11377C/G, and + 276G/T polymorphisms and risk of T2D through a meta-analysis.

METHODS

A systematic search was performed in the PubMed, Web of science, Scopus and Cochrane library databases to extract published studies according to the inclusion criteria. Among the 741 studies, 391 of them were screened as full text and 31 studies were finally included in the meta-analysis. Analysis of data was performed using random-effects model. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to analyze the strength of association. Subgroup and meta-regression analyses were performed to identify the potential source of heterogeneity.

RESULTS

The pooled analysis showed that there was no statistically significant association between genotypes of CC (OR = 0.76, 95% CI: 0.53-1.09, P = 0.14), CG (OR = 0.93, 95% CI: 0.72-1.20, P = 0.58) and GG (OR = 1, 95% CI: 0.80-1.26, P = 0.94) ADIPO - 11377 polymorphism with increased risk of T2D. In addition, the results revealed a trend toward an increased risk of T2D for the SNP + 276 TT genotype (OR = 0.87, 95% CI: 0.77-0.98, P = 0.026) as compared with the GT and GG genotypes. Subgroup analysis by ethnicity indicated significant association between the TT genotype of the SNP + 276 and increased risk of T2D among Europeans. Met-regression demonstrated significant association between the GT genotype of + 276 polymorphism with risk of T2D in male individuals (slope: 0.0006; 95% CI: 0.0002-0.0009; P < 0.001).

CONCLUSIONS

Collectively, our findings demonstrated a positive association between ADIPOQ + 276 G > T polymorphism with increased risk of T2D in male individuals with European ethnicity.

Adiponectin gene polymorphisms associated with diabetes mellitus: A descriptive review

Diabetes is currently a growing concern of the age. Prevention and treatment of diabetes is a global health priority. Adiponectin is an adipocyte derived protein hormone that enhances insulin sensitivity and ameliorates diabetes by enhancing fatty acid oxidation and glucose uptake in skeletal muscle and reducing glucose production in the liver. Low serum adiponectin concentrations are associated with diabetes, central obesity, insulin resistance and metabolic syndrome. Adiponectin gene is located on chromosome 3q27, where a locus of susceptibility to diabetes was mapped. Several cross-sectional studies showed that single nucleotide polymorphisms (SNPs) in adiponectin gene (ADIPOQ) were associated with diabetes. SNPs in ADIPOQ help in assessing the association of common variants with levels of adiponectin and the risk of diabetes. Two common SNPs, rs2241766 and rs1501299, have been linked significantly to type 1 diabetes mellitus which endow the world with a block of haplotypes. Experimental evidences also suggest that rs1501299, rs2241766, rs266729, rs17366743, rs17300539, rs182052, rs822396, rs17846866, rs3774261 and rs822393 are significantly associated with type 2 diabetes mellitus which is the predominant form of the disease. In addition, rs2241766 and rs266729 are extensively associated with gestational diabetes, a condition that develops in women during pregnancy. Therefore not a particular single mutation but a number of SNPs in adiponectin gene could be a risk factor for developing diabetes among the individuals worldwide. This study firmly suggests that adiponectin plays a crucial role in the pathogenesis of type 1, type 2 and gestational diabetes mellitus.

Meta-analysis of the association between adiponectin SNP 45, SNP 276, and type 2 diabetes mellitus

Objective

The present study aimed to determine whether the polymorphisms at rs2241766 and rs1501299 on the ADIPOQ gene were related to the susceptibility of type 2 diabetes mellitus (T2DM).

Methods

Eight databases, PubMed, GWAS, Embase, Lochrane, Ebsco, CNKI (Chinese National Knowledge Infrastructure), VIP (Viper Database) and ChinaInfo were searched, and a meta-analysis of susceptibility was conducted between SNP45, SNP276 polymorphisms and T2DM. Furthermore, HWE test was conducted to assess the genetic balance of the study, evaluate the quality of Newcastle–Ottawa quality assessment scale (NOS), and establishing allelic, dominant, recessive, heterozygous, and homozygous gene models.

Results

This meta-analysis included 53 articles, encompassing 9285 cases with rs2241766 and 14156 controls and 7747 cases with rs1501299 and 10607 controls. For the rs2241766 locus, a significant correlation was found in the three models by the subgroup analysis. Western Asians: dominant gene model (TT + TG vs. GG, P = 0.01); heterozygous gene model (TG vs. GG, P = 0.02); homozygous gene model (TT vs. GG, P = 0.01). South Asians: dominant gene model (TT + TG vs. GG, P = 0.004); heterozygous gene model (TG vs. GG, P = 0.009); homozygous gene model (TT vs. GG, P = 0.005). However, no statistically significant correlation was established among the five genetic models for rs1501299 locus.

Conclusion

The findings of the present study indicated that the T allele of rs2241766 polymorphism is the susceptibility locus of T2DM in the West Asian population, but has a protective effect in the South Asian population, albeit further studies are needed in other populations. Also, no association was found between the ADIPOQ rs1501299 polymorphism and T2DM.

Association between adiponectin rs17300539 and rs266729 gene polymorphisms with serum adiponectin level in an Iranian diabetic/pre-diabetic population

OBJECTIVE

Adiponectin is an adipokine that is mostly secreted from adipose tissues and has a significant role in the improvement of insulin resistant and type 2 diabetes mellitus (T2DM). This study is conducted to examine the association of rs17300539 and rs266729 with T2DM and serum adiponectin level in Iranian population.

METHOD

A case-control study was conducted on 80 individuals with fasting plasma glucose (FPG) >100 (mg/dl) as diabetic-pre-diabetic group, and 80 individuals with fasting plasma glucose 70-100 (mg/dl) as control group. DNA extraction was done on samples and genotyping method was performed by PCR-RFLP.

RESULT

The frequency of GA genotype in rs17300539 (diabetic/pre-diabetic 35.5%, control 11.3%, (OR [95%CI]=4.18[1.8-9.6]; p=0.001) and allele A (diabetic/pre-diabetic 31%, control 9%, (OR [95% CI]=4.67[2-10.7]) was significantly more in diabetic/pre-diabetic group compared to control group. The difference in the genotype frequency for rs266729 in diabetic group compared to that in control was not significant. The levels of adiponectin in diabetic cases had no difference compared to the control group in both polymorphisms. The rs266729 was not associated with any metabolic parameter except waist circumference (p=0.03), however, rs17300539 shows association only with fasting plasma glucose, triglyceride, and total cholesterol (p=0.007, 0.039, 0.0032, respectively).

CONCLUSION

Our findings showed that there is an association between rs17300539 with the increase of T2DM but rs266729 showed no association with the risk of T2DM. Allele A of rs17300539 increased the risk of diabetes. There is no association between adiponectin level and both polymorphisms.

Associations of SNPs of the ADIPOQ Gene with Serum Adiponectin Levels, Unstable Angina, and Coronary Artery Disease

Adiponectin is encoded by the ADIPOQ gene and participates in the pathogenesis of cardiovascular and metabolic diseases. The goal of the study was to assess associations of rs17300539, rs266729, rs182052, rs2241766, and rs17366743 single nucleotide polymorphisms (SNPs) of the ADIPOQ gene with concentrations of serum adiponectin and with coronary atherosclerosis and type 2 diabetes mellitus in 447 patients (316 men and 131 women) subjected to coronary angiography. SNPs of the ADIPOQ gene of the study participants were genotyped using real-time PCR. Multivariate linear regression adjusted for covariates revealed significant association between rs182052 SNP and serum adiponectin concentration (β= -0.11; 95% confidence interval (95%CI): -0.19, -0.03; p = 0.016). Regression analysis revealed an increase in prevalence of unstable angina (OR (odds ratio) = 2.55; 95%CI 1.4-4.82; p = 0.018) and coronary artery disease (OR = 1.55; 95%CI 1.15-2.09; p = 0.021) per copy of the rs182052 A allele. Prevalence of type 2 diabetes mellitus was higher in subjects with the rs182052 A allele (OR = 2.29; 95%CI 1.29-4.21; p = 0.024). Regression analysis of rs266729 showed that prevalence of unstable angina was increased (OR = 3.59; 95%CI 1.17-10.01; p = 0.045) in the subjects with the GG genotype and prevalence of coronary artery disease (CAD) was significantly increased (OR = 1.48; 95%CI 1.09-2.03; p = 0.045) per copy of the G allele. Haplotype analysis revealed that the subjects with the GCATT haplotype have lower adiponectin levels (β= -0.15; p = 0.042) and higher prevalence of unstable angina (OR = 3.597; p = 0.007) compared with reference haplotype carriers. Thus, the results indicate that minor A allele of rs182052 of the ADIPOQ gene is significantly associated with a decrease in serum adiponectin levels, and two SNPs (rs182052 and rs266729) of the ADIPOQ gene are significantly associated with cardiovascular and metabolic diseases.

Adiponectin Expression and Genotypes in Italian People with Severe Obesity Undergone a Hypocaloric Diet and Physical Exercise Program

Adiponectin exerts positive effects on metabolic and inflammatory processes. Adiponectin levels and some single-nucleotide polymorphisms (SNPs) seem to be associated with obesity. Here, we investigated the effects of a 4-week Hypocaloric diet and Physical exercise Program (HPP) on 268 young people with severe obesity. We evaluated the relationship between adiponectin levels and anthropometric and biochemical parameters, at baseline and after a 4-week HPP. Finally, we investigated some adiponectin gene variants and their correlation to biochemical parameters. Adiponectin levels were statistically lower in people with severe obesity than in controls. At the end of the HPP, all the people with severe obesity showed a Body Mass Index (BMI) reduction with a statistically significant increase in adiponectin levels. Genotyping, the adiponectin gene demonstrated a significant difference in 3 polymorphisms within the people with severe obesity. Besides, c.11377C>G and c.11391G>A homozygous subjects experienced more advantages by HPP. Furthermore, c.268G>A heterozygous subjects showed an enhancement in lipid profile as well in adiponectin levels. The best predictor of the changes in adiponectin levels was represented by the c.268G>A WT allele. Our study confirmed that a 4-weeks HPP in people with severe obesity results in metabolic amelioration associated with a significant increase of adiponectin levels. Importantly, we found that a specific genetic background in the ADIPOQ gene can predispose toward a more significant weight loss.

Genetic variants in promoter regions associated with type 2 diabetes mellitus: A large-scale meta-analysis and subgroup analysis

BACKGROUND

Promoter plays important roles in regulating transcription of genes. Association studies of genetic variants in promoter region with type 2 diabetes (T2D) risk have been reported, but most were limited to small number of individual genetic variants and insufficient sample sizes. In addition, the effect of study populations and demographic characteristics were often neglected.

METHODS

In this study, we conducted a large-scale meta-analysis and subgroup analysis of T2D associated genetic variants in the promoter regions to evaluate their contribution to the susceptibility in T2D. Alleles and genotypes from cohort or case-controlled studies were extracted for future study. Total 41 742 cases and 50 493 controls for three loci were involved in 70 articles.

RESULTS

Seventy case-controlled studies of three genes with 41 742 cases and 50 493 controls were included. Meta-analysis showed only rs266729 and rs17300539 of ADIPOQ, and rs1884613, rs2144908, and rs4810424 of HNF4A were significantly associated with T2D risk. Subgroup analysis showed that both rs266729 and rs17300539 of ADIPOQ were associated with the risk of T2D in Caucasian population, but only rs266729 of ADIPOQ in Asian population and rs2144908 in other population including multinational North American. For diagnostic criteria, rs266729 of ADIPOQ and rs2144908 of HNF4A were associated with T2D risk when WHO/ADA diagnostic criteria were used. For genotyping methods, both rs266729 of ADIPOQ and rs2144908 of HNF4A were associated with T2D risk when other than Taqman and Sequencing methods were used.

CONCLUSIONS

T2D was significantly associated with promoter rs266729, rs17300539, rs1884613, rs2144908, and rs4810424, and the association of T2D risk were affected by study population, diagnostic criteria, and genotype methods.

Adiponectin is associated with cardio-metabolic traits in Mexican children

The adipocyte-derived adiponectin hormone bridges obesity and its cardio-metabolic complications. Genetic variants at the ADIPOQ locus, in ADIPOR1, and ADIPOR2 have been associated with adiponectin concentrations and cardio-metabolic complications in diverse ethnicities. However, no studies have examined these associations in Mexican children. We recruited 1 457 Mexican children from Mexico City. Six genetic variants in or near ADIPOQ (rs182052, rs2241766, rs266729, rs822393), ADIPOR1 (rs10920533), and ADIPOR2 (rs11061971) were genotyped. Associations between serum adiponectin, genetic variants, and cardio-metabolic traits were assessed using linear and logistic regressions adjusted for age, sex, and recruitment center. Serum adiponectin concentration was negatively associated with body mass index, waist to hip ratio, low-density lipoprotein cholesterol, total cholesterol, triglycerides, fasting glucose, fasting insulin, homeostatic model assessment of insulin resistance, dyslipidemia and overweight/obesity status (7.76 × 10⁻⁴⁰ ≤ p ≤ 3.00 × 10⁻³). No significant associations between genetic variants in ADIPOQ, ADIPOR1, and ADIPOR2 and serum adiponectin concentration were identified (all p ≥ 0.30). No significant associations between the six genetic variants and cardio-metabolic traits were observed after Bonferroni correction (all p < 6.9 × 10⁻⁴). Our study suggests strong associations between circulating adiponectin concentration and cardio-metabolic traits in Mexican children.

Adiponectin Single Nucleotide Polymorphisms and Serum Levels Are Relevant to Prognosis of Patients With Aneurysmal Subarachnoid Hemorrhages

To investigate the association of adiponectin gene polymorphisms and its levels with aneurysmal subarachnoid hemorrhages (aSAHs) prognosis. This case-control study enrolled 138 patients with aSAH and 102 healthy controls as case group and control group, respectively. Prognosis of case group was evaluated using Glasgow Outcome Scale. Polymerase chain reaction-restriction fragment length polymorphism was used to examine the genotypes of 45T>G and -11377C>G. Enzyme-linked immunosorbent assay was used to detect adiponectin levels. Logistic regression analysis was applied to assess the association of adiponectin gene polymorphism with aSAH prognosis. Case group had increased GG genotype and G allele genotype frequencies of 45T>G and -11377C>G compared with control group (all P < 0.01). In case group, TT genotype had the highest adiponectin level compared with both TG and GC genotypes (both P < 0.05). As for -11377C>G, GG genotype had the lowest adiponectin levels, followed by CG genotype and CC genotype in both groups (P < 0.05). In general, case group had decreased adiponectin levels compared with control group (P < 0.05). Univariate analysis showed that hypertension, Hunt-Hess grade, aneurysm size, aneurysms multiplicity and -11377C>G were associated with aSAH prognosis, while multivariate logistic regression analysis confirmed that hypertension, Hunt-Hess grade, residual flow in aneurysms and aneurysm size were independent risk factors for aSAH prognosis. Decreased adiponectin levels may be a pathological index for aSAH, which may be explain by the G allele of -11377C>G in adiponectin. Moreover, hypertension, Hunt-Hess grade, residual flow in aneurysms and aneurysm size may be independent risk factors for aSAH prognosis.

Association Between Interleukin-10 Gene (-1082g/A) Polymorphism and Type 2 Diabetes, Diabetes-Related Traits, and Microvascular Complications in the Croatian Population

Interleukin (IL)-10 is an anti-inflammatory cytokine, and a decrease in its secretion is associated with obesity, metabolic syndrome and type 2 diabetes. However, it has not been established whether the intensity of the immune response during diabetes-associated chronic inflammation affects the development and/or progression of type 2 diabetes and its microvascular complications. The aim of this study was to investigate the role of single nucleotide polymorphism (SNP)-1082G/A for IL-10 gene in development of diabetes type 2 and its complications. DNA was extracted from blood cells of 240 overweight/obese subjects for IL-10 genotyping. Based on the presence of diabetes type 2, patients were divided in two groups: experimental group of 144 patients with diabetes type 2 and control group of 96 age- and gender-matched subjects without diabetes. Compared to control group, diabetic group had higher levels of leukocytes (p=0.012), fibrinogen (p=0.049) and plasminogen activator inhibitor-1 (PAI-1) (p=0.009), and lower levels of albumin (p=0.001). There were no differences in the frequency of SNP-1082G/A for IL-10 gene between the two groups (p=0.654). When considering diabetes related traits in all subjects in relation to specific genotype, a group with homozygous (AA) genotype had higher values of the mean fasting glucose (p<0.000001), HbA1c (p<0.000001) and HOMA-IR (p=0.003632), while the mean HOMA-B value (p=0.000178) was lower when compared to the groups with GG and GA genotypes. There was no difference in devel-opment of diabetic nephropathy, retinopathy and polyneuropathy between the IL-10 polymorphism genotypes. In conclusion, obese diabetes type 2 patients had an increased inflammation activity com-pared to obese non-diabetic individuals. There was no association of the investigated polymorphisms and development of type 2 diabetes and its microvascular complications. However, diabetes related traits clearly depended on the presence of specific IL-10 genotype.

Susceptible and Prognostic Genetic Factors Associated with Diabetic Peripheral Neuropathy: A Comprehensive Literature Review

Type 2 diabetes mellitus (T2D) is a disorder of glucose metabolism. It is a complex process involving the regulation of insulin secretion, insulin sensitivity, gluconeogenesis, and glucose uptake at the cellular level. Diabetic peripheral neuropathy (DPN) is one of the debilitating complications that is present in approximately 50% of diabetic patients. It is the primary cause of diabetes-related hospital admissions and nontraumatic foot amputations. The pathogenesis of diabetic neuropathy is a complex process that involves hyperglycemia-induced oxidative stress and altered polyol metabolism that changes the nerve microvasculature, altered growth factor support, and deregulated lipid metabolism. Recent literature has reported that there are several heterogeneous groups of susceptible genetic loci which clearly contribute to the development of DPN. Several studies have reported that some patients with prediabetes develop neuropathic complications, whereas others demonstrated little evidence of neuropathy even after long-standing diabetes. There is emerging evidence that genetic factors may contribute to the development of DPN. This paper aims to provide an up-to-date review of the susceptible and prognostic genetic factors associated with DPN. An extensive survey of the scientific literature published in PubMed using the search terms "Diabetic peripheral neuropathy/genetics" and "genome-wide association study" was carried out, and the most recent and relevant literature were included in this review.

The polymorphism of rs266729 in adiponectin gene and type 2 diabetes mellitus: A Meta-Analysis

Genome-wide association studies and meta-analyses indicate that the polymorphism of rs266729 in adiponectin gene increases the risk of type 2 diabetes mellitus (T2DM); however, these study methods have not been able to identify the underlying genetic effect on the development of T2DM. A genetic model-free approach was conducted to determine the underlying genetic model of inheritance of T2DM because of rs266729 in adiponectin gene.We searched available studies on the association between the rs266729 in adiponectin gene and T2DM in accordance with the inclusion and exclusion criteria. Based on the information extracted from the studies, generalized odds ratio value (GOR) was used to evaluate whether the rs266729 polymorphism was a risk factor for T2DM. The parameter λ was calculated to estimate the genetic model, which was defined as the quotient of natural logarithm odds ratio of GC to CC divided by the natural logarithm odds ratio of GG to CC. Finally, binary logistic regression analysis was used to calculate the genetic effect of rs266729 on T2DM.Data from 7 studies were included in this meta-analysis. The total number of subjects was 12,323, comprising 5,948 cases and 6,395 controls. Mean (standard deviation) age of cases was 59.50 (11.53), and that of the controls was 53.80 (11.65), whereas the proportion of male was 40.9 and 50.0%, respectively. GOR was 1.13 (1.02, 1.25) and λ was 0.47 (0.29, 0.64). The result of logistic regression indicated that the G allele influenced the development of T2DM in the additive model, whereas the genetic effect was 1.13 (1.06, 1.19). Sources of control populations were the cause of between-study heterogeneity; nonetheless, there was no publication bias among studies.The G allele of rs266729 in adiponectin gene increases the risk of T2DM through an additive genetic model with an effect of 1.13 (1.06, 1.19).

Plasma adiponectin levels, ADIPOQ variants, and incidence of type 2 diabetes: A nested case-control study

AIMS

To clarify the associations between plasma adiponectin levels and ADIPOQ variants with type 2 diabetes incidence in a general Japanese population.

METHODS

We conducted a case-control study nested within the Japan Public Health Center-based Prospective Study. We measured plasma adiponectin levels and genotyped +45T>G (rs2241766) and +276G>T (rs1501299) in the ADIPOQ gene among 417 incident diabetes cases and 1197 control subjects matched by age, sex, and area.

RESULTS

After potential confounding factor adjustment, the multivariable-adjusted diabetes odds ratios (ORs) were 0.59 (95% confidence interval [CI]: 0.51-0.68) and 0.68 (95% CI: 0.60-0.78) per 1 standard deviation increment in the log-transformed levels of total- and high-molecular-weight (HMW) adiponectin levels, respectively. However, the ADIPOQ variants were not significantly associated with plasma adiponectin levels (for total adiponectin, +45 P=0.15 and +276 P=0.08) and diabetes risk (+45 P=0.70 and +276 P=0.72) under the additive genetic model.

CONCLUSIONS

Our prospective findings suggest that both total and HMW adiponectin levels are strongly and inversely associated with diabetes risk after adjustment for potential confounding factors; however, the ADIPOQ variants +45 and +276 are not associated with adiponectin levels and diabetes risk in the general Japanese population.

Family-Based Association Study of rs17300539 and rs12495941 Polymorphism in Adiponectin Gene and Polycystic Ovary Syndrome in a Chinese Population

Backgriond

Polycystic ovary syndrome (PCOS) is a complex disease that has both genetic and environmental components. Adiponectin plays an important role in the regulation of insulin sensitivity and insulin resistance (IR) in PCOS. The aim of this study was to determine 2 single-nucleotide polymorphisms (SNPs) variants (rs12495941 and rs17300539) of the adiponectin gene (ADIPOQ) in polycystic ovary syndrome (PCOS) families.

Material/Methods

We recruited 197 PCOS probands, their biological parents, and 192 controls. Anthropometric variables, including hip circumference (HC) and waist circumference (WC), were measured in all subjects during their first visit to the outpatient department. Serum T, FBG, FINS, TC, TG, LDL, and HDL levels were measured. PCOS patients were divided into 2 groups based on BMI: group A (BMI <25 kg/m²) and group B (BMI ≥25 kg/m²). Parents of PCOS were accordingly categorized into group C and group D (fathers), and group E and group F (mothers). The associations among ADIPOQ rs12495941, rs17300539, and PCOS were analyzed using the transmission disequilibrium test (TDT).

Results

A significant association was found between SNP rs17300539 and PCOS in our Chinese population. The levels of TG and FINS and the genotype frequencies of rs17300539 are significantly different between overweight and lean PCOS. No significant association was detected for rs12495941.

Conclusions

TDT confirms that rs17300539 of ADIPOQ is strongly associated with the risk of PCOS in a Chinese Han population, but rs12495941 of ADIPOQ is not associated with the occurrence of PCOS.

High Molecular Weight Adiponectin Levels are Neither Influenced by Adiponectin Polymorphisms Nor Associated with Insulin Resistance in Mixed-ancestry Hyperglycemic Subjects from South Africa

Background

High molecular weight (HMW) adiponectin has antiatherogenic, antiinflammatory and antidiabetic properties and these effects have been linked to its effect on high density lipoprotein cholesterol (HDL-c). Single nucleotide polymorphisms (SNPs) in the adiponectin gene influence adiponectin levels. We examined the relationship between HMW-adiponectin levels and cardiometabolic traits in normo- and hyperglycemic mixed ancestry South Africans and correlated these levels to two common polymorphisms.

Methods

HMW-adiponectin was determined in 101 subjects from the Cape Town Bellville South community-based study on a mixed ancestry population. Comparisons were made between individuals with normo- and hyperglycemia. Two common SNPs, ADIPOQ SNPs rs17300539 and rs266729, known to affect adiponectin levels were also tested for. Levels of HMW-adiponectin were then correlated with cardiometabolic traits in all groups.

Results

Levels of HMW-adiponectin were not significantly different in the normo- and hyperglycemic groups (median 11.6 vs. 10.5 μg/mL, p=0.3060) and in men and women (8.44 vs. 11.34 μg/mL, p=0.67). ADIPOQ SNPs rs17300539 and rs266729 did not influence levels of HMW-adiponectin. Robust correlation analyses revealed a significant positive correlation between HMW-adiponectin and HDL-c (r=0.45; 95%CI: 0.27–0.59), similarly in normo- and hyperglycemic participants (p > 0.99). This association was substantially attenuated in robust linear regressions adjusted for age, gender and adiposity.

Conclusions

Adiponectin levels in this population were not determined by the commonest SNPs of the adiponectin gene, were unaffected by glycemic status; but were significantly correlated with HDL-c levels. Previous studies have attributed some of the beneficial effects of adiponectin to its effect on HDL-c.

Correlation between HFE gene polymorphisms and increased risk of coronary artery disease among patients with type 2 diabetes in Iran

BACKGROUND/AIM

Diabetes mellitus is a risk factor for cardiovascular diseases (CVDs), which are among the major causes of deaths in type 2 diabetes (T2D). The purpose of the present study was to determine the association of C282Y and H63D mutations in the HFE gene with increased risk of coronary artery disease (CAD) in T2D patients.

MATERIALS AND METHODS

Two hundred and ninety individuals were divided into two groups: a case group and a control group. Genomic DNA of peripheral venous blood cells was extracted and the HFE gene mutations were analyzed using the PCR-RFLP technique.

RESULTS

Data analysis revealed a significant difference between the allele frequencies of H63D and C282Y mutations between the case group and the controls (P < 0.05). The relationships between the GA and GG genotypes in C282Y and H63D mutations in terms of fasting blood sugar (FBS), lipid profile (total cholesterol, triglycerides, high-density lipoproteins (HDL), low-density lipoproteins), body mass index (BMI), HbA1c, micro albuminuria, and creatine levels did not show a significant differences between the two groups (P > 0.05). Using a logistic regression model, BMI, FBS, HDL, and total cholesterol levels were significantly different with independent predictors of CVD (P < 0.05).

CONCLUSION

Our results revealed a significant correlation between C282Y and H63D mutations and the development of CAD in T2D patients.

The Role of Adiponectin in Cardiometabolic Diseases: Effects of Nutritional Interventions

Adiponectin is an adipocyte-derived hormone abundantly present in plasma that exerts its effects through the activation of 3 receptors. Its concentrations are negatively regulated by the accumulation of visceral fat, and clinical studies implicate hypoadiponectinemia in the pathogenesis of diabetes mellitus type 2, coronary artery disease, hypertension, and left ventricular hypertrophy. In contrast, high concentrations of adiponectin are associated with a decreased risk of coronary artery disease, with an improvement in the differentiation of preadipocytes into adipocytes, and with increased endothelial nitric oxide production. Therefore, adiponectin appears to be an important molecule involved in limiting the pathogenesis of obesity-linked disorders, and it may have potential benefits in the treatment and prevention of cardiovascular disease. Caloric restriction, moderate alcohol consumption, and consuming a Mediterranean diet increase adiponectin concentrations, and current evidence suggests a positive, dose-dependent relation between ω-3 (n-3) fatty acid intake and circulating concentrations of adiponectin. Recently, it was reported that the administration of aged garlic extract and a single food intervention with pistachios can increase adiponectin concentrations in individuals with metabolic syndrome. Moreover, the Mediterranean diet is associated with higher adiponectin concentrations. Additional studies are needed to evaluate the potential benefits of increasing adiponectin by nutritional interventions in the treatment and prevention of cardiometabolic diseases.

Adiponectin Gene Polymorphisms are Associated with Increased Risk of Colorectal Cancer

Background

This meta-analysis investigates the associations of adiponectin (ADIPOQ) genetic polymorphisms with the susceptibility to colorectal cancer (CRC).

Material/Methods

2 reviewers independently searched 6 databases – PubMed, Cochrane Library, Ovid, Embase, China National Knowledge Infrastructure (CNKI) and Wanfang databases – to identify published studies relevant to adiponectin gene polymorphisms and CRC. Studies retrieved from database searches were screened using our stringent inclusion and exclusion criteria. Full texts of the selected studies were accessed and related data was extracted using a standardized data extraction form. Comprehensive Meta-analysis 2.0 software was used for statistical analyses.

Results

A total of 188 studies were initially retrieved from database search, and 6 studies were eventually selected, through a rigorous screening process, for inclusion in this meta-analysis. The 6 studies contained a total of 1897 patients (Asians: 1190; white: 707) with CRC in case group and 2475 healthy controls (Asians: 1325; white: 1150) in the control group. Results of the current meta-analysis revealed that the rs2241766 T>G single-nucleotide polymorphisms (SNP) increase the risk of CRC; rs1501299 G>T under dominant model was associated with increased risk of CRC; and rs266729 C>G SNP under allele model conferred an increased risk of CRC.

Conclusions

Our meta-analysis strongly suggests that the ADIPOQ rs2241766 T>G, rs1501299 G>T, and rs266729 C>G SNPs correlate with an increased risk of CRC.

Association of adiponectin gene polymorphisms with an elevated risk of diabetic peripheral neuropathy in type 2 diabetes patients

OBJECTIVE

In this study, we examined the association between two adiponectin (ADPN) gene polymorphisms, +45T/G and +276G/T, and susceptibility to diabetic peripheral neuropathy (DPN) in type 2 diabetes mellitus (T2DM) patients.

METHODS

A total of 180 T2DM patients were enrolled in this study and assigned to two groups: DPN group (n=90) and non-DPN (NDPN) group (n=90). In addition, 90 healthy subjects were chosen as healthy normal control (NC). The plasma level of ADPN was quantified by ELISA method and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used for genotype analysis of the two ADPN polymorphisms, +45T/G (rs2241766) and +276G/T (rs1501299), in all the study subjects. Statistical analysis of data was performed with SPSS version 20.0 software.

RESULTS

Serum levels of ADPN were markedly reduced in the DPN group compared to NDPN and NC groups (all P<0.05). The frequencies of TT, TG and GG genotypes and the T and G alleles of T45G and G276T polymorphisms in DPN group were significantly different than the NDPN group (all P<0.05). Notably, T45G and G276T polymorphisms were associated with significantly reduced plasma levels of ADPN in DPN and NDPN groups, compared to the NC group (P<0.001). Significant difference in ADPN plasma levels were also observed between TT, TG and GG genotypes of T45G and G276T polymorphisms. Our results indicate that the T allele in +45T/G and +276G/T polymorphisms is correlated with an elevated risk of DPN in T2DM patients. Haplotype analysis showed that GG and GT haplotypes showed a negative relationship with DPN, while TG haplotype positively correlated with risk of DPN in T2DM patients (all P<0.05).

CONCLUSION

Our results show that T45G and G276T polymorphisms of ADPN are associated with a significantly elevated risk of DPN in T2DM patients, likely by down-regulating ADPN serum level.

Pathogenesis and management of the diabetogenic effect of statins: a role for adiponectin and coenzyme Q10?

There is growing evidence to suggest that statin therapy is associated with an increased risk of incident diabetes. The risk for statin-related diabetes depends upon many factors including age, pre-existing diabetic risk, type and potency of statin. Several mechanisms have been suggested for the diabetogenic effects of statins involving processes that alter islet ß-cell function, resulting in impaired glucose metabolism. Recent evidence suggests that the association of statin therapy with the development of diabetes may be partly mediated by a statin-induced decrease in circulating adiponectin and coenzyme Q10. The available evidence suggests the benefit of statins in reducing cardiovascular events outweigh the risk of developing diabetes. Moreover, statin therapy does not impair glycemic control in diabetic patients. Expert recommendations for the use of statins in people at risk of developing diabetes have recently been published. However, further research is required to elucidate both the association between statin use and incident diabetes as well as underlying mechanisms.

The association of circulating adiponectin and + 45 T/G polymorphism of adiponectin gene with gestational diabetes mellitus in Iranian population

Background

Adiponectin is an adipokine with insulin-sensitizing effects. We investigated the relationship between the single nucleotide polymorphism (SNP) +45 T > G ( rs 2241766 ;Gly15Gly) in the adiponectin gene, serum adiponectin levels, insulin resistance and risk of gestational diabetes (GDM) in Iranian population.

Methods

65 GDM patients and 70 healthy pregnant women were enrolled in this study. Genotyping for SNP +45 T > G in the adiponectin gene ( rs 2241766 ) was performed by the polymerase chain reaction-restriction fragment length polymorphism method. The level of fasting serum adiponectin, insulin, glucose, and lipid levels were measured. Insulin resistance was estimated using homeostasis model of assessment for insulin resistance (HOMA-IR).

Results

The G allele and TG/GG genotype of rs 2241766 were more frequent than the T allele and TT genotype in GDM patients compared to the controls (p < 0.05). Multiple logistic regression analysis revealed that the risk of GDM was significantly higher in subjects with the TG/GG genotype to those with TT genotype [odds ratio = 2.38, 95% CI 1.09-5.22, p = 0.030]. No significant association was observed between genotypes of rs 2241766 and circulating concentrations of adiponectin. Multiple regression analysis showed that serum adiponectin levels was negatively associated with HOMA-IR in GDM patients (β = −0.385, p <0.01).

Conclusion

The findings demonstrated that TG/GG genotype of rs 2241766 was an independent risk factor of GDM in our population. Furthermore, circulating adiponectin level was negatively correlated with insulin resistance in GDM patients.

Association between ADIPOQ +45T>G polymorphism and type 2 diabetes: a systematic review and meta-analysis

Recently, a number of studies have reported the association between the single nucleotide polymorphisms (SNPs) +45T>G polymorphism in the adiponectin (ADIPOQ) gene and type 2 diabetes mellitus (T2DM) risk, though the results are inconsistent. In order to obtain a more precise estimation of the relationship, a meta-analysis was performed. In this current study, the Medline, Embase, Pubmed, ISI Web of Knowledge, Ovid, Science Citation Index Expanded Database, Wanfang Database, and China National Knowledge Infrastructure were searched for eligible studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to estimate the strength of association. Forty-five publications were included in the final meta-analysis with 9986 T2DM patients and 16,222 controls for ADIPOQ +45T>G polymorphism according to our inclusion and exclusion criteria. The +45T>G polymorphism was associated with an overall significantly increased risk of T2DM (G vs. T: OR = 1.18, 95% CI = 1.06–1.32; The dominant model: OR = 1.18, 95% CI = 1.03–1.33; The recessive model: OR = 1.47, 95% CI = 1.20–1.78; The homozygous model: OR = 1.62, 95% CI = 1.25–2.09; Except the heterozygous model: OR = 1.11, 95% CI = 0.98–1.24). Subgroup analysis revealed a significant association between the +45T>G polymorphism and T2D in an Asian population. Thus, this meta-analysis indicates that the G allele of the ADIPOQ +45T>G polymorphisms associated with a significantly increased risk of T2DM in the Asian population.

Associations between variants on ADIPOQ and ADIPOR1 with colorectal cancer risk: a Chinese case-control study and updated meta-analysis

Background

Epidemiological studies have suggested that variants on adiponectin (ADIPOQ) and its receptor ADIPOR1 (adiponectin receptor 1) are associated with colorectal cancer (CRC) risk; however, the results were inconclusive. The aim of the study was to evaluate the associations between the variants on ADIPOQ and ADIPOR1 and the CRC risk with a hospital-based case-control study in the Chinese population along with meta-analysis of available epidemiological studies.

Methods

With a hospital-based case-control study of 341 cases and 727 controls, the associations between the common variants on ADIPOQ (rs266729, rs822395, rs2241766 and rs1501299) and ADIPOR1 (rs1342387 and rs12733285) and CRC susceptibility were evaluated. Meta-analysis of the published epidemiological studies was performed to investigate the associations between the variants and CRC risk.

Results

For the population study, we found that variant rs1342387 of ADIPOR1 was associated with a reduced risk for CRC [adjusted odds ratio (OR) = 0.74, 95% confidential intervals (95% CI) = 0.57-0.97; CT/TT vs. CC]. The meta-analysis also suggested a significant association for rs1342387 and CRC risk; the pooled OR was 0.79 (95% CI = 0.66-0.95) for the CT/TT carriers compared to CC homozygotes under the random-effects model (Q = 8.06, df = 4, P = 0.089; I² = 50.4%). The case-control study found no significant association for variants rs266729, rs822395, rs2241766, and rs1501299 on ADIPOQ or variant rs12733285 on ADIPOR1 and CRC susceptibility, which were consistent with results from the meta-analysis studies.

Conclusions

These data suggested that variant rs1342387 on ADIPOR1 may be a novel CRC susceptibility factor.

Electronic supplementary material

The online version of this article (doi:10.1186/s12881-014-0137-y) contains supplementary material, which is available to authorized users.

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.

Association of variants on ADIPOQ and AdipoR1 and the prognosis of gastric cancer patients after gastrectomy treatment

Adiponectin is a protein hormone secreted exclusively by adipocytes and it is responsible for insulin sensitization in the human body. Deregulation of adiponectin and its downstream signaling pathway genes have been found to be involved in the gastric cancer carcinogenesis; however, whether the variants on adiponectin (ADIPOQ) and adiponectin receptor 1 (ADIPOR1) affect the prognosis of gastric cancer patients are still unknown. Here we have recruited 455 gastric cancer patients, who have received the gastrectomy treatment to evaluate the prognostic effects of variants on ADIPOQ (rs266729 and rs822395) and AdipoR1 (rs12733285 and rs1342387) for the gastric cancer patients. No significant association between the four variants and the overall survival of the gastric cancer patients was found. However, for those patients without a previous history of alcohol drinking, the rs266729 GG/CG genotype carriers showed a significantly decreased gastric cancer mortality compared to homogeneity CC patients (HR 0.74, 95 % CI 0.56-0.97; p = 0.032) after adjustment for variants age, sex, smoking status, tumor stage, tumor location and post-surgery chemotherapy. No significant association between the variant rs266729 genotypes and overall survival for the gastric cancer patients with an alcohol drinking habit. These data suggested that the variant rs266729 was an independent prognostic factor for the never drinking gastric cancer patients who received surgical treatment.

Proteomic and genomic studies of non-alcoholic fatty liver disease - clues in the pathogenesis

Non-alcoholic fatty liver disease (NAFLD) is a widely prevalent hepatic disorder that covers wide spectrum of liver pathology. NAFLD is strongly associated with liver inflammation, metabolic hyperlipidaemia and insulin resistance. Frequently, NAFLD has been considered as the hepatic manifestation of metabolic syndrome. The pathophysiology of NAFLD has not been fully elucidated. Some patients can remain in the stage of simple steatosis, which generally is a benign condition; whereas others can develop liver inflammation and progress into non-alcoholic steatohepatitis, fibrosis, cirrhosis and hepatocellular carcinoma. The mechanism behind the progression is still not fully understood. Much ongoing proteomic researches have focused on discovering the unbiased circulating biochemical markers to allow early detection and treatment of NAFLD. Comprehensive genomic studies have also begun to provide new insights into the gene polymorphism to understand patient-disease variations. Therefore, NAFLD is considered a complex and mutifactorial disease phenotype resulting from environmental exposures acting on a susceptible polygenic background. This paper reviewed the current status of proteomic and genomic studies that have contributed to the understanding of NAFLD pathogenesis. For proteomics section, this review highlighted functional proteins that involved in: (1) transportation; (2) metabolic pathway; (3) acute phase reaction; (4) anti-inflammatory; (5) extracellular matrix; and (6) immune system. In the genomic studies, this review will discuss genes which involved in: (1) lipolysis; (2) adipokines; and (3) cytokines production.

Gene-environment interaction between adiponectin gene polymorphisms and environmental factors on the risk of diabetic retinopathy

AIMS/INTRODUCTION

To evaluate whether the adiponectin gene is associated with diabetic retinopathy (DR) risk and interaction with environmental factors modifies the DR risk, and to investigate the relationship between serum adiponectin levels and DR.

MATERIALS AND METHODS

Four adiponectin polymorphisms were evaluated in 372 DR cases and 145 controls. Differences in environmental factors between cases and controls were evaluated by unconditional logistic regression analysis. The model-free multifactor dimensionality reduction method and traditional multiple regression models were applied to explore interactions between the polymorphisms and environmental factors.

RESULTS

Using the Bonferroni method, we found no significant associations between four adiponectin polymorphisms and DR susceptibility. Multivariate logistic regression found that physical activity played a protective role in the progress of DR, whereas family history of diabetes (odds ratio 1.75) and insulin therapy (odds ratio 1.78) were associated with an increased risk for DR. The interaction between the C-11377 G (rs266729) polymorphism and insulin therapy might be associated with DR risk. Family history of diabetes combined with insulin therapy also increased the risk of DR. No adiponectin gene polymorphisms influenced the serum adiponectin levels. Serum adiponectin levels did not differ between the DR group and non-DR group.

CONCLUSIONS

No significant association was identified between four adiponectin polymorphisms and DR susceptibility after stringent Bonferroni correction. The interaction between C-11377G (rs266729) polymorphism and insulin therapy, as well as the interaction between family history of diabetes and insulin therapy, might be associated with DR susceptibility.

Association of adiponectin (ADIPOQ) rs2241766 polymorphism and dyslipidemia in HIV/HCV-coinfected patients

BACKGROUND

The adiponectin (ADIPOQ) rs2241766 polymorphism is related to metabolic abnormalities. The aim of this study was to evaluate the association of the ADIPOQ rs2241766 polymorphism with serum dyslipidemia and insulin resistance (IR) in human immunodeficiency virus (HIV)/hepatitis C virus (HCV)-coinfected patients.

METHODS

We carried out a cross-sectional study on 262 patients. ADIPOQ rs2241766 polymorphisms were genotyped by GoldenGate® assay. Generalized linear models (GLMs) were used to compare continuous outcome variables (total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), non-HDL-C and homeostatic model assessment (HOMA)) and categorical outcome variables (TC≥200 mg/dL, TG≥170 mg/dL, LDL-C≥100 mg/dL, HDL-C≤35 mg/dL, non-HDL-C≥120 mg/dL and HOMA≥3·8) according to ADIPOQ genotype under a dominant inheritance model.

RESULTS

Patients with the rs2241766 GG/GT genotype had significantly lower serum TC levels (P=0·038) and percentages of TC≥200 mg/dL (P=0·022) than rs2241766 TT carriers. When adjusted GLM was performed, rs2241766 GG/GT was associated with low serum TC levels (arithmetic mean ratio (AMR)=0·92 [(95% CI=0·85; 0·99) P=0·024]) and low likelihood of TC≥200 mg/dL (odds ratio (OR)=0·32 [(95% CI=0·11; 0·88) P=0·027]. When stratifying by steatosis, no significant values were found for patients without steatosis. However, for patients with steatosis, rs2241766 GG/GT genotypes were related to low TC serum values of TC (AMR=0·89; P=0·027), LDL-C (AMR=0·85; P=0·039) and non-HDL-C (AMR=0·86; P=0·015). No significant associations were found between rs2241766 and HOMA values.

CONCLUSIONS

The presence of the ADIPOQ rs2241766 G allele (GG/GT genotype) was associated with a protective effect against dyslipidemia, primarily in HIV/HCV-coinfected patients with steatosis.

Association between 276G/T adiponectin gene polymorphism and new-onset diabetes after kidney transplantation

BACKGROUND

New-onset diabetes after transplantation (NODAT) is a well-recognized complication of kidney transplantation and is associated with poor outcomes. Both adiponectin and chemokine ligand 5 (CCL5) proteins are related to glucose metabolism and genetic variations in their genes can lead to development of NODAT. The aim of this study was to investigate the association of adiponectin and CCL5 genes polymorphisms with NODAT in a population of Caucasian kidney transplant recipients.

METHODS

Two hundred seventy Caucasian kidney transplant recipients (83 with NODAT and 187 without NODAT) were included in a nested case-control study. Patients with pretransplantation diabetes mellitus and multiorgan transplantation were excluded. NODAT diagnosis was determined by American Diabetes Association criteria. Subjects were genotyped for 276G/T adiponectin gene polymorphism (rs1501299) and rs2280789 and rs3817655 CCL5 gene polymorphisms by real-time polymerase chain reaction.

RESULTS

The TT genotype of 276G/T adiponectin gene polymorphism was significantly more frequent in NODAT than non-NODAT patients compared with GG/GT genotypes (recessive model; P=0.031). TT genotype was identified as an independent risk factor for NODAT in Caucasian kidney transplant recipients after adjusting for age at transplantation, pretransplantation body mass index, and use of tacrolimus (TT vs. GG/GT, hazard ratio=1.88, 95% confidence interval=1.03-3.45, P=0.041). There were no differences in genotype distribution and allele frequency of rs2280789 and rs3817655 CCL5 gene polymorphisms between NODAT and non-NODAT groups.

CONCLUSIONS

The 276G/T adiponectin gene polymorphism is associated with NODAT in Caucasian kidney transplant recipients.

Adiponectin gene polymorphisms in Egyptian type 2 diabetes mellitus patients with and without diabetic nephropathy

Recently, several reports addressed the associations of adiponectin (ADIPOQ) gene polymorphisms with abnormal adiponectin serum levels, type 2 diabetes mellitus (T2DM), and diabetic nephropathy (DN); however, results are inconsistent. This study aimed to investigate the possible association of ADIPOQ gene polymorphisms with T2DM and/or DN and whether they affect serum adiponectin levels in Egyptian population. Two hundred and ninety-six T2DM patients (100 normoalbuminuric patients, 103 microalbuminuric patients, and 93 macroalbuminuric patients) and 209 controls were enrolled in the present study. Polymorphisms of +45, -11391, and +276 of the ADIPOQ gene were detected using polymerase chain reaction restriction fragment length polymorphism. Serum adiponectin was measured using ELISA. Our results revealed that ADIPOQ +45 TG and GG genotypes and G allele were significantly associated with T2DM, micro/macroalbuminuria, and decreased serum adiponectin level. ADIPOQ -11391 AA genotype frequency was significantly increased in T2DM group. Moreover, GA and AA genotypes and A allele of ADIPOQ -11391 were significantly associated with susceptibility to macroalbuminuria despite increased serum adiponectin concentrations. While, ADIPOQ +276 TT genotype and T allele were protective factors regarding the susceptibility to T2DM and micro/macroalbuminuria, and they were significantly associated with increased adiponectin levels. We observed also that the decrease of the serum Adiponectin level was accompanied by an insulin resistance, albuminuria, as well as an increase of serum creatinine. We concluded that ADIPOQ +45; ADIPOQ -11391 gene polymorphisms are associated with T2DM and/or DN in Egyptian population. While, ADIPOQ +276 gene polymorphism is a protective factor regarding T2DM and/or DN susceptibility.