Association of the T-G polymorphism in adiponectin (exon 2) with obesity and insulin sensitivity: interaction with family history of type 2 diabetes

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.

A dominant negative ADIPOQ mutation in a diabetic family with renal disease, hypoadiponectinemia, and hyperceramidemia

Adiponectin, encoded by ADIPOQ, is an insulin-sensitizing, anti-inflammatory, and renoprotective adipokine that activates receptors with intrinsic ceramidase activity. We identified a family harboring a 10-nucleotide deletion mutation in ADIPOQ that cosegregates with diabetes and end-stage renal disease. This mutation introduces a frameshift in exon 3, resulting in a premature termination codon that disrupts translation of adiponectin's globular domain. Subjects with the mutation had dramatically reduced circulating adiponectin and increased long-chain ceramides levels. Functional studies suggest that the mutated protein acts as a dominant negative through its interaction with non-mutated adiponectin, decreasing circulating adiponectin levels, and correlating with metabolic disease.

Reproducibility and discrimination of different indices of insulin sensitivity and insulin secretion

Aims

Insulin sensitivity and insulin secretion can be estimated by multiple indices from fasting blood samples or blood samples obtained during oral glucose tolerance tests. The test-retest reliability of these indices in repeated measurements within the same individuals can strongly vary.

Methods

We analyzed data of persons without diabetes who underwent two repeated OGTTs. For each measurement pair, we calculated multiple commonly used indices for the assessment of insulin secretion and insulin sensitivity. We then evaluated the coefficient of variation (standard deviation/mean) and discriminant ratio for each index.

Results

89 persons underwent two OGTTs with a median interval of 86 days (IQR 64–249). Among indices of insulin sensitivity derived from fasting blood samples, the revised quantitative insulin sensitivity check index had the smallest coefficient of variation (2.8 ± 2.1%) whereas the C-peptide based homeostasis model assessment 2 had the highest discriminant ratio (1.97 (1.65–2.39)). As for insulin sensitivity indices that are based on OGTT, the oral glucose insulin sensitivity index had the smallest coefficient of variation (6.5 ± 5.1%). The highest discriminant ratio was found for the non-esterified fatty acids-based insulin sensitivity index (NEFA-ISI, 2.70 (2.30–3.22)). For the assessment of insulin secretion from fasting variables, the lowest mean coefficient of variation was found for C-peptide based homeostasis model assessment 2 beta with 10.8 ± 8% and the highest discriminant ratio for the C-peptide / Glucose-Ratio (2.18 (1.84–2.63)). Among indices assessing insulin secretion from an OGTT, the lowest coefficient of variation was found for the ratio of the areas under the C-peptide and glucose curves from 0 to 120 minutes with 11.3 ± 9.7%.

Conclusion

The data reveal large differences in the reproducibility and the discrimination capability of different indices that assess insulin sensitivity or insulin secretion. Our findings can aid the selection of an appropriate index in clinical studies.

Exploratory Study on Expression of Fatty Tissue in Gestational Diabetes Mouse

Objective

To investigate the changes of UCP1 protein in brown fat by establishing a model of gestational diabetes mellitus through intervention of high fat and carbohydrate diet. To explore the changes of UCP1 protein in brown fat in gestational diabetic mice, and analyze the characteristics of abnormal glucose metabolism in gestational diabetic mice and its relationship with changes in adipocyte morphology and insulin resistance.

Methods

Eighty C57BL/6J pregnant mice were randomly divided into a normal control group and a high-fat and high-sugar feeding group. The normal control group was fed a normal diet, while the high-fat and high-sugar group was fed a high-fat and high-sugar diet to establish a gestational diabetes mellitus (GDM) model. On the pregnancy days 0, 10, and 18, the weight and fasting glucose were measured. On the pregnancy day 18, the triglycerides (TG), the total cholesterol (TC), free fatty acid (FFA), insulin levels, and insulin resistance index (HOMA-IR) were measured or calculated. At the same time, brown fat UCP1 protein of the two groups of pregnant mice were measured using Western blot Observed the Adipose tissue pathological changes by staining HE. The adipocyte was observed, and the correlation was analyzed.

Results

Twenty-one pregnant mice reach the level of gestational diabetes diagnosis (FBG ≥ 5.1 mmol/L) in the high-fat and high-sugar diet group. On the pregnancy day 10 and 18, the fasting plasma glucose and the body weight significantly increased (P < 0.05). The total cholesterol, triglycerides, free fatty acid, insulin level, and insulin resistance index of the GDM group were also higher compared with that of the control group (P < 0.05). The adipocyte size significantly increased in the GDM mice. TG, TC, FFA, and body weight at 18 days of gestation were significantly correlated with HOMA-IR and single-adipocyte area in the GDM mice. HOMA-IR was significantly correlated with a single-adipocyte area. Compared with the normal control group, the UCP1 proteins of GDM mice decreased significantly and negatively correlated with body weight increase.

Conclusion

Feeding C57BL/6J pregnant mice with high fat and high sugar to establish a gestational diabetes mouse model has good stability and is similar to human gestational diabetes. The reduction of brown fat UCP1 protein in GDM mice has a certain correlation with obesity tendency and obvious insulin resistance.

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.

Association of ADIPOQ rs266729 and rs1501299 gene polymorphisms and circulating adiponectin level with the risk of type 2 diabetes in a population of Iran: a case-control study

Purpose

Mutation in various regions of the adiponectin (ADIPOQ) gene is described to be associated with type 2 diabetes (T2D). Our aim was to investigate the association between rs1501299 (SNP + 276 G > T) and rs266729 (SNP-11377 C > G) polymorphisms of ADIPOQ gene and susceptibility to T2D in an Iranian population.

Methods

This is a case-control study. A total of 210 subjects including 100 patients with T2D and 110 healthy controls were selected from an Iranian population. SNP-11377 C > G and SNP + 276 G > T polymorphisms were investigated using the Tetra ARMS-PCR method.

Results

The genotypes frequency of the SNP-11377 C > G polymorphism (P = 0.21) and SNP + 276 G > T polymorphism (P = 0.10) were in agreement with the Hardy-Weinberg equilibrium. The genotype and allele frequencies for rs266729 polymorphism showed a significant difference between the T2D and control groups. Further, the frequencies of the genotypes of GG (OR = 2.43, P = 0.031), GG + GG (OR = 2.11, P < 0.01) and G allele (OR = 1.6, P = 0.041) in SNP-11377 C > G polymorphism was significantly associated with an increased risk of T2D compared to control group. While, there was no significant association between the different genotypes of SNP + 276 G > T polymorphism and the risk of T2D in an Iranian population. The circulating adiponectin level in T2D subjects had significant difference compared to the control group in rs266729 polymorphism.

Conclusion

We concluded that ADIPOQ rs266729 (SNP-11377 C > G) gene polymorphism but no rs1501299 is associated with increased risk of T2D in our population.

The autophagy protein Becn1 improves insulin sensitivity by promoting adiponectin secretion via exocyst binding

Autophagy dysregulation is implicated in metabolic diseases, including type 2 diabetes. However, the mechanism by which the autophagy machinery regulates metabolism is largely unknown. Autophagy is generally considered a degradation process via lysosomes. Here, we unveil a metabolically important non-cell-autonomous, non-degradative mechanism regulated by the essential autophagy protein Becn1 in adipose tissue. Upon high-fat diet challenge, autophagy-hyperactive Becn1^F121A mice show systemically improved insulin sensitivity and enhanced activation of AMP-activated protein kinase (AMPK), a central regulator of energy homeostasis, via a non-cell-autonomous mechanism mediated by adiponectin, an adipose-derived metabolic hormone. Adipose-specific Becn1^F121A expression is sufficient to activate AMPK in non-adipose tissues and improve systemic insulin sensitivity by increasing adiponectin secretion. Further, Becn1 enhances adiponectin secretion by interacting with components of the exocyst complex via the coiled-coil domain. Together, our study demonstrates that Becn1 improves insulin sensitivity by facilitating adiponectin secretion through binding the exocyst in adipose tissue.

Kuramoto et al. demonstrate a non-degradative and non-cell-autonomous mechanism by which the autophagy protein Becn1 regulates systemic energy metabolism. Becn1 interacts with exocyst proteins in white adipose tissue to facilitate adiponectin secretion, resulting in systemic insulin sensitization via the adiponectin receptor-AMPK signaling pathway in non-adipose tissues.

Modeling different types of diabetes using human pluripotent stem cells

Diabetes mellitus (DM) is a metabolic disease characterized by chronic hyperglycemia as a result of progressive loss of pancreatic β cells, which could lead to several debilitating complications. Different paths, triggered by several genetic and environmental factors, lead to the loss of pancreatic β cells and/or function. Understanding these many paths to β cell damage or dysfunction could help in identifying therapeutic approaches specific for each path. Most of our knowledge about diabetes pathophysiology has been obtained from studies on animal models, which do not fully recapitulate human diabetes phenotypes. Currently, human pluripotent stem cell (hPSC) technology is a powerful tool for generating in vitro human models, which could provide key information about the disease pathogenesis and provide cells for personalized therapies. The recent progress in generating functional hPSC-derived β cells in combination with the rapid development in genomic and genome-editing technologies offer multiple options to understand the cellular and molecular mechanisms underlying the development of different types of diabetes. Recently, several in vitro hPSC-based strategies have been used for studying monogenic and polygenic forms of diabetes. This review summarizes the current knowledge about different hPSC-based diabetes models and how these models improved our current understanding of the pathophysiology of distinct forms of diabetes. Also, it highlights the progress in generating functional β cells in vitro, and discusses the current challenges and future perspectives related to the use of the in vitro hPSC-based strategies.

Type 2 diabetes risk gene Dusp8 regulates hypothalamic Jnk signaling and insulin sensitivity

Recent genome-wide association studies (GWAS) identified DUSP8, encoding a dual-specificity phosphatase targeting mitogen-activated protein kinases, as a type 2 diabetes (T2D) risk gene. Here, we reveal that Dusp8 is a gatekeeper in the hypothalamic control of glucose homeostasis in mice and humans. Male, but not female, Dusp8 loss-of-function mice, either with global or corticotropin-releasing hormone neuron-specific deletion, had impaired systemic glucose tolerance and insulin sensitivity when exposed to high-fat diet (HFD). Mechanistically, we found impaired hypothalamic-pituitary-adrenal axis feedback, blunted sympathetic responsiveness, and chronically elevated corticosterone levels driven by hypothalamic hyperactivation of Jnk signaling. Accordingly, global Jnk1 ablation, AAV-mediated Dusp8 overexpression in the mediobasal hypothalamus, or metyrapone-induced chemical adrenalectomy rescued the impaired glucose homeostasis of obese male Dusp8-KO mice, respectively. The sex-specific role of murine Dusp8 in governing hypothalamic Jnk signaling, insulin sensitivity, and systemic glucose tolerance was consistent with functional MRI data in human volunteers that revealed an association of the DUSP8 rs2334499 risk variant with hypothalamic insulin resistance in men. Further, expression of DUSP8 was increased in the infundibular nucleus of T2D humans. In summary, our findings suggest the GWAS-identified gene Dusp8 as a novel hypothalamic factor that plays a functional role in the etiology of T2D.

Pathophysiology-based subphenotyping of individuals at elevated risk for type 2 diabetes

The state of intermediate hyperglycemia is indicative of elevated risk of developing type 2 diabetes1. However, the current definition of prediabetes neither reflects subphenotypes of pathophysiology of type 2 diabetes nor is predictive of future metabolic trajectories. We used partitioning on variables derived from oral glucose tolerance tests, MRI-measured body fat distribution, liver fat content and genetic risk in a cohort of extensively phenotyped individuals who are at increased risk for type 2 diabetes2,3 to identify six distinct clusters of subphenotypes. Three of the identified subphenotypes have increased glycemia (clusters 3, 5 and 6), but only individuals in clusters 5 and 3 have imminent diabetes risks. By contrast, those in cluster 6 have moderate risk of type 2 diabetes, but an increased risk of kidney disease and all-cause mortality. Findings were replicated in an independent cohort using simple anthropomorphic and glycemic constructs4. This proof-of-concept study demonstrates that pathophysiological heterogeneity exists before diagnosis of type 2 diabetes and highlights a group of individuals who have an increased risk of complications without rapid progression to overt type 2 diabetes.

Role of Adiponectin and Brain Derived Neurotrophic Factor in Metabolic Regulation Involved in Adiposity and Body Fat Browning

Obesity, characterized by excessive fat mass, has been emerging as a major global epidemic and contributes to the increased risk of morbidity around the world. Thus, the necessity to find effective therapy and specific regulatory mechanisms is increasing for controlling obesity. Lately, many researchers have been interested in the linkage between obesity and adipokines/myokines, particularly adiponectin and brain-derived neurotrophic factor (BDNF). However, the role of adiponectin and BDNF in adiposity has not been clearly defined yet. We examined the association of adiposity with adiponectin and BDNF through human study (observational study) with Korean women and in vitro experiments. In the human study, we found a negative relationship between adiposity and circulating adiponectins but irregular patterns in the relationship between adiposity and circulating BDNFs. In the in vitro study using 3T3-L1 adipocytes, adiponectin treatment strongly promoted adipocyte differentiation and the fat browning process, whereas BDNF treatment attenuated adipocyte differentiation and the fat browning process in differentiated adipocytes. Our results demonstrate that adiponectin and BDNF play an important role in regulating fat mass and the expression of fat-browning markers in different ways, and also suggest that circulating adiponectin may be used as an important monitoring index for obesity status.

Association of omentin-1, adiponectin, and resistin genetic polymorphisms with systemic lupus erythematosus in a Chinese population

OBJECTIVE

An increasing number of studies have demonstrated the roles of adipokines in systemic lupus erythematosus (SLE). We aimed to investigate the association of genetic variations of omentin-1, adiponectin, and resistin with SLE susceptibility.

METHODS

We selected 623 SLE patients and 665 normal controls in the present study. Genotyping of omentin-1 rs2274907, rs35779394, rs79209815, and rs13376023; adiponectin rs16861194 and rs266729; and resistin rs1862513, rs3745368, and rs3745367 was conducted by TaqMan SNP genotyping assays.

RESULTS

Overall, we found no significant differences in the allele or genotype frequencies of the nine studied SNPs between the SLE patients and controls. However, an increased frequency of the resistin rs3745368 variant was observed in the SLE patients under the dominant model (P = 0.024). In omentin-1, the rs13376023 A allele was found to be related to oral ulcers in SLE patients (P = 0.013), and the rs35779394 C and rs13376023 A allele frequencies were significantly lower in SLE patients with BMI ≥ 24 kg/m² (P = 0.019, P = 0.033, respectively). For resistin, the frequencies of the rs3745368 AA genotype and A allele were lower in SLE patients with discoid rash (P = 0.036, P = 0.011), and the rs3745368 A allele frequency was higher in SLE patients with lupus nephritis (P = 0.018). The resistin rs3745367 AA genotype and A allele frequencies were related to the occurrence of renal disorder in SLE patients (P = 0.024, P = 0.009). The haplotype analysis showed that the CGA haplotype of resistin was associated with susceptibility to SLE (P = 0.005). No significant associations of plasma omentin-1, adiponectin or resistin levels with their respective genotypes were found in SLE patients.

CONCLUSIONS

In summary, omentin-1, adiponectin and resistin SNPs are not associated with the genetic background of SLE in Chinese patients. However, omentin-1 and resistin genetic variations might contribute to several clinical phenotypes of SLE.

A genetic analysis identifies a haplotype at adiponectin locus: Association with obesity and type 2 diabetes

Adiponectin is a prime determinant of the status of insulin resistance. Association studies between adiponectin (ADIPOQ) gene single nucleotide polymorphisms (SNPs) and metabolic diseases have been reported earlier. However, results are ambiguous due to apparent contradictions. Hence, we investigated (1) the association between ADIPOQ SNPs: −11377C/G, +10211T/G, +45T/G and +276G/T for the risk towards type 2 diabetes (T2D) and, (2) genotype-phenotype association of these SNPs with various biochemical parameters in two cohorts. Genomic DNA of diabetic patients and controls from Gujarat and, Jammu and Kashmir (J&K) were genotyped using PCR-RFLP, TaqMan assay and MassArray. Transcript levels of ADIPOQ were assessed in visceral adipose tissue samples, and plasma adiponectin levels were estimated by qPCR and ELISA respectively. Results suggest: (i) reduced HMW adiponectin/total adiponectin ratio in Gujarat patients and its association with +10211T/G and +276G/T, and reduced ADIPOQ transcript levels in T2D, (ii) association of the above SNPs with increased FBG, BMI, TG, TC in Gujarat patients and (iii) increased GGTG haplotype in obese patients of Gujarat population and, (iv) association of −11377C/G with T2D in J&K population. Reduced HMW adiponectin, in the backdrop of obesity and ADIPOQ genetic variants might alter metabolic profile posing risk towards T2D.

Variants in ADIPOQ gene are linked to adiponectin levels and lung function in young males independent of obesity

Background

Obesity is a major risk factor for many chronic diseases, including reduced lung function. The role of polymorphisms of the adiponectin gene, though linked with cardiometabolic consequences of obesity, has not been studied in relation to lung function.

Objectives

The aim of this study is to examine polymorphisms in the ADIPOQ, ADIPOR1, and ADIPOR2 genes in relation to adiponectin serum levels, BMI, and adiposity in 18-year old Cypriot males, as well as determine whether BMI, adipokines levels and polymorphisms in adipokine related genes are associated with lung function levels.

Results

From the participants, 8% were classified as obese, 22% as overweight, and the remaining 71% as normal. We found that rs266729 and rs1501299 in ADIPOQ and rs10920531 in ADIPOR1 were significantly associated with serum adiponectin levels, after adjusting for ever smoking. In addition, there was an overall significant increase in FEV₁% predicted with increasing BMI (β = 0.53, 95% CI: 0.27, 0.78) and in FVC % predicted (β = 1.02, 95% CI: 0.73, 1.30). There was also a decrease in FEV₁/FVC with increasing BMI (β = -0.53, 95% CI: -0.71, -0.35). Finally, rs1501299 was associated with lung function measures.

Discussion

Functional variants in the ADIPOQ gene were linked with lung function in young males. Further studies should concentrate on the role of adipokines on lung function which may direct novel therapeutic approaches.

Pure additive contribution of genetic variants to a risk prediction model using propensity score matching: application to type 2 diabetes

The achievements of genome-wide association studies have suggested ways to predict diseases, such as type 2 diabetes (T2D), using single-nucleotide polymorphisms (SNPs). Most T2D risk prediction models have used SNPs in combination with demographic variables. However, it is difficult to evaluate the pure additive contribution of genetic variants to classically used demographic models. Since prediction models include some heritable traits, such as body mass index, the contribution of SNPs using unmatched case-control samples may be underestimated. In this article, we propose a method that uses propensity score matching to avoid underestimation by matching case and control samples, thereby determining the pure additive contribution of SNPs. To illustrate the proposed propensity score matching method, we used SNP data from the Korea Association Resources project and reported SNPs from the genome-wide association study catalog. We selected various SNP sets via stepwise logistic regression (SLR), least absolute shrinkage and selection operator (LASSO), and the elastic-net (EN) algorithm. Using these SNP sets, we made predictions using SLR, LASSO, and EN as logistic regression modeling techniques. The accuracy of the predictions was compared in terms of area under the receiver operating characteristic curve (AUC). The contribution of SNPs to T2D was evaluated by the difference in the AUC between models using only demographic variables and models that included the SNPs. The largest difference among our models showed that the AUC of the model using genetic variants with demographic variables could be 0.107 higher than that of the corresponding model using only demographic variables.

Adiponectin and human eating behaviour: a Mendelian randomization study

Background

Adiponectin plays key roles in regulating appetite and food intake. Altered circulating adiponectin levels have been observed in human eating disorders such as anorexia nervosa, bulimia nervosa or binge eating. In addition, an association between circulating adiponectin levels and human eating behaviour (EB) has been reported. Interestingly, a disturbance in eating behaviour is the defining characteristic of human eating disorders. However, it is unknown whether adiponectin is causally implicated in human EB. We therefore aimed to investigate the causal effect of adiponectin on EB.

Results

Mendelian randomization (MR) analysis estimated the influence of blood adiponectin on EB by combining data on the association of adiponectin gene (ADIPOQ) variants with adiponectin levels and with three EB factors involving disinhibition, restraint and hunger. Using inverse-variance weighted (IVW) regression method and other complementary MR techniques (weighted median regression, MR Egger and weighted modal regression), the MR analysis revealed a broadly consistent evidence that higher blood adiponectin concentration was significantly associated with increased EB factor disinhibition (beta coefficient for IVW regression [βIVW], 3.05; 95% confidence interval [CI] 1.10, 5.00) but non-significantly associated with increased EB factor restraint (βIVW, 0.17; 95% CI − 1.85, 2.18), and increased EB factor hunger (βIVW, 1.63; 95% CI − 0.75, 4.01).

Conclusions

Overall, our findings indicate a causal role of adiponectin levels in eating disinhibition but not in eating restraint and hunger.

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.

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.

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.

Association between +45T>G adiponectin polymorphism gene and type 2 diabetes mellitus and metabolic syndrome in a Venezuelan population

Background: Adiponectin (ADIPOQ) is a hormone primarily synthesized by adipocytes and encoded by the ADIPOQ gene, which exerts anti-inflammatory, antiatheratogenic and insulin sensitizing functions. It has been shown that its plasma concentrations are decreased in individuals with metabolic syndrome (MS) and type 2 diabetes mellitus (DM2), which could be due to variations in the gene coding for this protein. The aim of this study was to detect the +45 T>G polymorphism of the ADIPOQ gene in subjects with DM2 and MS in Maracaibo municipality, Zulia state, Venezuela. Methods: A total of 90 subjects who attended the Center for Metabolic Endocrine Research "Dr. Félix Gómez" were enrolled for this study, 46 of which had MS-DM2 and 44 of which were healthy control individuals. Genomic DNA was extracted from blood samples and PCR-restriction fragment length polymorphism analysis was carried out for the promoter region of the ADIPOQ gene. Likewise, the +45 T> G polymorphism was identified and correlated with MS and DM2 in the studied population. Results: The most frequent allele in both groups was the T allele, and the predominant genotype was homozygous T/T (79%). Genotypes with heterozygous T/G and G/G homozygous polymorphism were more frequent in the control group than in the MS-DM2 group. Regarding the individuals with T/G and G/G genotypes, statistically significant lower mean values ​​were found for fasting glucose, total cholesterol, triacylglycerides, abdominal circumference, and for the medians of systolic and diastolic blood pressure. Odds ratio were calculated for the presence or absence of MS and DM2. Conclusions: The results suggested that the presence of the G allele exerts a protective effect on the carrier individuals, thus avoiding the appearance of the aforementioned metabolic alterations.

Role of rs1501299 variant in the adiponectin gene on total adiponectin levels, insulin resistance and weight loss after a Mediterranean hypocaloric diet

BACKGROUND/AIM

Several adiponectin gene (ADIPOQ) single nucleotide polymorphisms (SNPS) have been related with adiponectin levels and risk for obesity. Our aim was to analyze the effects of rs1501299 ADIPOQ gene polymorphism on total adiponectin levels, insulin resistance and weight loss after a Mediterranean hypocaloric diet in obese subjects.

METHODS

A Caucasian population of 82 obese patients was analyzed, before and after 3 months on a Mediterranean hypocaloric diet. Before and after 3 months on a hypocaloric diet, an anthropometric evaluation, an assessment of nutritional intake and a biochemical analysis were performed.

RESULTS

After dietary treatment and in wild type group, weight, BMI, fat mass, leptin levels, systolic blood pressure and waist circumference decreases were similar to the mutant type group. In wild type group, the decrease in total cholesterol was -28.1 ± 15.3 mg/dl (mutant group: -12.6 ± 16.7 mg/dl:p = 0.009), LDL- cholesterol was -31.8 ± 20.5 mg/dl (-12.2 ± 11.5 mg/dl:p = 0.006), fasting glucose plasma -4.8 ± 2.5 mg/dL (-0.5 ± 0.1 mg/dL:p = 0.02), insulin -3.6 ± 1.5 mUI/L (+0.6 ± 1.1 mUI/L:p = 0.02) and HOMA-IR -1.2 ± 0.9 (-0.1 ± 1.1:p = 0.03).

CONCLUSION

The present study suggests that T allele of ADIPO (rs1501299) could be a predictor of a lack of response of HOMA-IR, insulin, fasting glucose and LDL cholesterol secondary to a Mediterranean hypocaloric diet in obese subjects.

Sex-Specific Associations of Testosterone With Metabolic Traits

Background: Testosterone levels are differentially linked with diabetes risk in men and women: lower testosterone levels in men and higher testosterone levels in women are associated with type 2 diabetes, though, the mechanisms are not fully clear. We addressed sex-specific links between testosterone and major pathogenetic mechanisms of diabetes. Methods: We analyzed data of 623 subjects (202 male, 345 female without, and 76 female with oral contraceptive therapy [OCT]) for whom insulin sensitivity and insulin secretion were assessed by oral glucose tolerance test. Body fat percentage was assessed by bioelectrical impedance. Testosterone was measured by enzyme-linked immunoassay; free testosterone and Framingham risk score were calculated. Results: There were significant interactions between testosterone and sex for all tested metabolic traits. Increasing testosterone was associated with less body fat, elevated insulin sensitivity, and reduced glycemia, independent of adiposity in men. In women without OCT, testosterone correlated with more body fat, insulin resistance, and higher glucose concentrations. Testosterone was not associated with insulin secretion in either sex, but with lower Framingham risk score in men and higher Framingham risk score in women. Conclusions: Similar to diabetes risk, insulin resistance has different association directions with testosterone levels in males and females. Insulin resistance could therefore constitute the best biological candidate linking testosterone levels and diabetes prevalence. The question of antiandrogen therapy being able to improve metabolism, glucose tolerance and cardiovascular risk in women was not clarified in our study but should be reviewed with higher numbers in a carefully matched study to reduce the influence of confounding variables.

Investigation of potential genomic biomarkers for obesity and personalized medicine

Obesity, as a global health issue, is a complex metabolic syndrome and its association with many chronic diseases. The pathology of obesity results from an interaction of psychological, environmental and variety of genetic factors. Etiologic determinants and molecular pathophysiology of obesity have not yet understood clearly. Previously shown that genetic markers have a significant role in the development of obesity, although results are divergent with populations. Turkish Cypriots have a unique mixture of allele distributions as being a small-islander population. Therefore, the current study was aimed to evaluate the association between obesity and three putative obesity-related ADIPOQ, FTO and ACE gene markers, respectively. We investigated a possible association of ADIPOQ rs2241766 G>T, FTO rs9939609 A>T and ACE rs4340288 DIP variants among obese and non-obese Turkish Cypriot origin. Additionally, the correlation between these variants and biochemical and physical measurements were also evaluated to determine the possible biomarker for obesity in the population. Only FTO rs9939609 A>T polymorphism was associated with obesity and no association was observed with ADIPOQ rs2441666 G>T and ACE rs4340288 DIP. To conclude, FTO rs9939609 A allele found to have strong association with obesity in the population of Turkish Cypriots.

Genetic association of ADIPOQ gene variants (-3971A>G and +276G>T) with obesity and metabolic syndrome in North Indian Punjabi population

BACKGROUND AND AIMS

At present obesity and metabolic syndrome (MetS) in India are the most challenging health problems. It is also well accepted that obesity is a significant risk factor for the development of metabolic syndrome and other degenerative diseases. Many studies have reported that single-nucleotide polymorphisms (SNPs) of the adiponectin (ADIPOQ) gene have been associated with obesity and its related disorders. Here, we aimed to investigate the association of two intronic variants in ADIPOQ gene, -3971A>G (rs822396) and +276G>T (rs1501299) with obesity and metabolic syndrome.

METHODS

Biochemical and anthropometric measurements were obtained from a total of 550 unrelated subjects (obese = 250 and non-obese = 300) of North Indian Punjabi population. Genotyping for the intron variants were performed by polymerase chain reaction based restriction fragment length polymorphism (PCR-RFLP) methods. After genotyping, as a quality control measure 10% of the samples for each polymorphism were confirmed by Sanger Sequencing method. The distributions of genotypic and allelic frequencies among obese and non-obese groups were compared by chi-square test and the corresponding risk was calculated using binary logistic regression. The effects of multiple testing were controlled by applying Bonferroni corrections.

RESULTS

All the anthropometric and biochemical parameters except triglycerides (TG) and very low-density lipoproteins cholesterol (VLDL-C) have shown significant association with both GG and TT genotypes of -3971A>G (rs822396) and +276G>T (rs1501299) polymorphisms respectively. The frequencies of GG (-3971A>G) and TT (+276G>T) genotypes were higher among obese cases (p = 0.008 and p = 0.035 respectively). However, no significant association was found between allelic frequencies of ADIPOQ rs822396 and obesity, whereas the association of ADIPOQ rs1501299 attenuated and became marginally significant after Bonferroni correction (p>0.025). Both the variant genotypes of ADIPOQ gene polymorphisms (-3971GG and +276TT) significantly increased the risk of development of obesity (OR: 1.52, p = 0.03; OR: 1.58, p = 0.04 respectively) and MetS (OR: 1.42, p = 0.03; OR: 1.57, p = 0.01 respectively) in the present population, after adjusting the various covariates. The G-T haplotype model (possessing -3971G and +276T alleles) was shown toprovide ~ 3 fold risk towards the obesity susceptibility (OR: 2.69, p = 0.009) and MetS risk (OR: 2.73, p = 0.009) and the association persisted after adjusting for different confounding variables.

CONCLUSION

The present study has confirmed that ADIPOQ -3971A>G (rs822396) and +276G>T (rs1501299) polymorphism may be clinically helpful to estimate obesity and MetS risk in North Indian Punjabi population.

Contribution of adiponectin polymorphisms to the risk of coronary artery disease in a North-African Tunisian population

BACKGROUND

Adiponectin, an adipocyte-derived protein, is known to play a key role in the processes leading to atherosclerosis and coronary artery disease (CAD) through its anti-atherogenic, anti-inflammatory, antioxidative, and anti-apoptotic properties. In the current study, we have studied the association of two single nucleotide polymorphisms (SNPs) +45 T>G (rs2241766) and +276 G>T (rs1501299) of the adiponectin gene with coronary artery disease (CAD) on an Arab/North-African population from Tunisia.

METHODS

Subjects comprised 277 patients with angiographically demonstrated CAD and 269 age- and gender-matched control subjects. The adiponectin genotypes were performed by polymerase chain reaction-restriction fragment length polymorphism analysis (PCR-RFLP). The contribution of adiponectin variants to CAD was analyzed by haplotype and regression analysis.

RESULTS

Adiponectin +45T>G and +276G>T genotypic and allelic distributions did not show a significant difference between cases and controls. Similarly, no association with CAD was observed for the haplotype analysis. Assuming dominant model of transmission for both polymorphisms and after adjustment of a number of traditional risk factors for CAD, logistic regression analysis showed an association of SNP +45 T>G with increased risk of developing CAD [adjusted OR (95% CI) = 2.59 (1.17-5.70); P = .01]. However, SNP + 276 G>T is associated with decreased risk of developing CAD [adjusted OR (95% CI) = 0.47 (0.22-0.97); P = .04].

CONCLUSION

There is no allelic or genotypic association of +45 T>G and +276 G>T of the adiponectin gene with CAD in the Tunisian population.

The association of SNP276G>T at adiponectin gene with insulin resistance and circulating adiponectin in response to two different hypocaloric diets

BACKGROUND

Several adiponectin gene (ADIPOQ) single nucleotide polymorphisms (SNPS) have been related with adiponectin levels and risk for obesity.

OBJECTIVE

The aim of our study was to analyze the effect of rs1501299 ADIPOQ gene polymorphism and dietary intake on total adiponectin levels and insulin resistance after two hypocaloric diets in obese subjects.

MATERIAL AND METHODS

A Caucasian population of 284 obese patients was enrolled in a randomized clinical trial with two hypocaloric diets (I: moderate carbohydrates vs II: low fat). Before and after 12 weeks on each hypocaloric diet, an anthropometric evaluation, an assessment of nutritional intake and a biochemical analysis were realized. The statistical analysis was performed for the combined GT and TT as a group (mutant) and GG as second group (wild) (dominant model).

RESULTS

The genotype distribution was 149 GG, 124 GT and 21 TT. With caloric restriction strategies, body weight, body mass index (BMI), fat mass, waist circumference, systolic blood pressure, total LDL cholesterol, LDL cholesterol and leptin levels decreased. Only in subjects with GG genotype, diet I and II decreased fasting insulin levels, HOMA-IR and adiponectin levels. The improvement was similar with both diets; insulin concentrations (Diet I: -4.7 ± 1.4 mUI/L vs. Diet II: -5.9 ± 1.9 mUI/L: p = .76), HOMA-IR (Diet I: -1.4 ± 0.6 units vs. Diet II: -2.0 ± 0.7 units: p = .56) and adiponectin levels (Diet I: -10.2 ± 3.4 ng/dl vs. Diet II: -14.0 ± 2.9 ng/dl: p = .33).

CONCLUSION

The GG genotype of ADIPOQ gene variant (rs1501299) is associated with an increase in adiponectin levels and a decrease of insulin and HOMA-IR after weight loss.

Effect of natural products on diabetes associated neurological disorders

Diabetes mellitus, a metabolic disorder, is associated with neurological complications such as depression, anxiety, hypolocomotion, cognitive dysfunction, phobias, anorexia, stroke, pain, etc. Traditional system of medicine is long known for its efficient management of diabetes. The current review discusses the scope of some common medicinal herbs as well as secondary metabolites with a special focus on diabetes-mediated central nervous system complications. Literatures suggest that natural products reduce diabetes-mediated neurological complications partly by reducing oxidative stress and/or inflammation or apoptosis in certain brain regions. Natural products are known to modulate diabetes-mediated alterations in the level of acetylcholinesterase, choline acetyltransferase, monoamine oxidase, serotonin receptors, muscarinic receptors, insulin receptor, nerve growth factor, brain-derived neurotrophic factor, and neuropeptide in brain. Further, there are several natural products reported to manage diabetic complications with unknown mechanism. In conclusion, medicinal plants or their secondary metabolites have a wide scope and possess therapeutic potential to effectively manage neurological complications associated with chronic diabetes.

T allele at ADIPOQ rs1501299 G/T polymorphism is more susceptible to the influence of circulating adiponectin on arterial stiffness in nondiabetic men

BACKGROUND

Low adiponectin levels are associated with increased insulin resistance (IR) and arterial stiffness in hypertensive patients, but higher adiponectin levels are also found in heart failure patients. This discrepancy has not been fully resolved, but it may be related to the adiponectin gene (ADIPOQ) which regulates adiponectin production. We aimed to investigate whether the relationship between adiponectin and arterial stiffness is associated with ADIPOQ rs1501299 G/T polymorphism in nondiabetic Korean men.

METHODS

In nondiabetic men without disease (n = 301), anthropometric parameters, lipid profiles, IR, circulating adiponectin, and brachial-ankle pulse wave velocity (baPWV) were measured. rs1501299 G/T polymorphism was also analyzed.

RESULTS

Circulating adiponectin levels were negatively correlated with baPWV and homeostatic model assessment-IR in the T allele carriers (n = 167), but this correlation was not observed in the GG subjects (n = 134). However, a positive correlation between baPWV and IR was observed in the GG subjects, but not in the T carriers. These patterns were maintained after the adjustment for confounding factors. A stepwise linear regression analysis revealed that circulating adiponectin and systolic blood pressure (BP) were the main influencing factors on baPWV levels in T carriers, but systolic BP, IR and age were the main contributors to increased baPWV levels in the GG subjects.

CONCLUSIONS

This study demonstrates that the relationship between circulating adiponectin and arterial stiffness is different according to ADIPOQ rs1501299 G/T polymorphism, and suggests that T allele is more susceptible to the influence of adiponectin on arterial stiffness than GG homozygotes. This information may prove to be useful for personal-based early prevention and management of atherosclerotic risk.

Emerging role of adipokines in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder characterized by multisystem organ involvement and unclear pathogenesis. Several adipokines synthesized in the adipose tissue, including leptin, adiponectin, resistin, and chemerin, have been explored in autoimmune rheumatic diseases, especially SLE, and results suggest that these mediators may be implicated in the pathogenesis of SLE. However, the current results are controversial. In this review, we will briefly discuss the expression and possible pathogenic role of several important adipokines, including leptin, adiponectin, resistin, and chemerin in SLE.

Relationships between adiponectin levels, the metabolic syndrome, and type 2 diabetes: a literature review

Elevated hepatic glucose production, impaired insulin secretion, and insulin resistance - abnormalities of glucose metabolism typically found in subjects with obesity - are major factors underlying the pathogenesis of type 2 diabetes (DM2) and the metabolic syndrome (MS). Adiponectin is a major regulator of glucose and lipid homeostasis via its insulin-sensitizing properties, and lower levels seems to be associated with the development of DM2 and MS. The purpose of this review is to clarify the mechanisms whereby adiponectin relates to the development of DM2 and MS and the association between polymorphisms of the adiponectin gene, circulating levels of the hormone, and its relationships with DM2. In addition, the impact of dietary lipids in the circulating levels of adiponectin will be addressed. According to the literature, circulating adiponectin levels seem to decrease as the number of MS components increases. Lower adiponectin concentrations are associated with higher intra-abdominal fat content. Therefore, adiponectin could link intra-abdominal fat with insulin resistance and development of MS. Therapeutic strategies that target the MS and its components, such as lifestyle modification through physical activity and weight loss, have been shown to increase adiponectin concentrations. Possible roles of diets containing either low or high amounts of fat, or different types of fat, have been analyzed in several studies, with heterogeneous results. Supplementation with n-3 PUFA modestly increases adiponectin levels, whereas conjugated linoleic acid supplementation appears to reduce concentrations when compared with unsaturated fatty acid supplementation used as an active placebo.

Excessive fuel availability amplifies the FTO-mediated obesity risk: results from the TUEF and Whitehall II studies

Variation in FTO is the most important common genetic determinant of body weight. Altered energy metabolism could underlie this association. We hypothesized that higher circulating glucose or triglycerides can amplify the FTO impact on BMI. In 2671 subjects of the TUEF study, we investigated the interaction effect of fasting glucose and triglyceride levels with rs9939609 in FTO on BMI. We analysed the same interaction effect by longitudinally utilizing mixed effect models in the prospective Whitehall II study. In TUEF, we detected an interaction effect between fasting glucose and fasting triglycerides with rs9939609 on BMI (p = 0.0005 and p = 5 × 10⁻⁷, respectively). The effect size of one risk allele was 1.4 ± 0.3 vs. 2.2 ± 0.44 kg/m² in persons with fasting glucose levels below and above the median, respectively. Fasting triglycerides above the median increased the per-allele effect from 1.4 ± 0.3 to 1.7 ± 0.4 kg/m². In the Whitehall II study, body weight increased by 2.96 ± 6.5 kg during a follow-up of 13.5 ± 4.6 yrs. Baseline fasting glucose and rs9939609 interacted on weight change (p = 0.009). Higher fasting glucose levels may amplify obesity-risk in FTO carriers and lead to an exaggerated weight gain over time. Since weight gain perpetuates metabolic alterations, this interplay may trigger a vicious circle that leads to obesity and diabetes.

Analysis of the correlation between adiponectin gene polymorphism and metabolic syndrome incidence and its relationship with the degree of atherosclerosis in patients

The aim of the present study was to determine the correlation between adiponectin (APN) gene polymorphism, metabolic syndrome incidence, and degree of atherosclerosis in patients with this disease. The study was conducted on 369 unrelated patients, diagnosed with metabolic abnormalities. The patients were divided into the metabolic syndrome group (MS group, n=182), the metabolic abnormality group (n=187) and the control group with metabolic normality (n=134), as per the degree of metabolic abnormality. The gene polymorphism of rs121917815 site of APN gene was detected by TaqMAN probe technique, and the OR values of different genotypes and alleles were calculated. The APN protein, C-reactive protein (CRP), IL-1 and high-density lipoprotein (HDL) 2a and 2b expression level changes were detected by immunoblotting. The atherosclerosis index (AI) of each allele in patients with MS was calculated. Compared with the control group, the expression levels of APN protein in the metabolic abnormality and MS groups were significantly decreased. However, there was no distinct difference in the comparison of gene polymorphism between the control and metabolic abnormality groups. The CC genotype frequency and C allele frequency of rs121917815 polymorphic site in the MS group were significantly increased, compared with the control group. The TT genotype frequency and T allele frequency were significantly decreased and the OR values of the CC genotype and C allele were increased. The results of immunoblotting showed that there was no obvious change of CRP, IL-1, HDL-2a and HDL-2b in the three groups, and there was no statistically significant difference in the comparison of AI between the MS and control groups as well as the metabolic abnormality group. The APN gene polymorphic site rs121917815 is associated with MS. The occurrence of CC genotype and C allele increased the incidence of MS, but it did not increase the degree of atherosclerosis in MS patients.

Leptin and adiponectin: pathophysiological role and possible therapeutic target of inflammation in ischemic stroke

Stroke is a multifactorial disease contributing to significant noncommunicable disease burden in developing countries. Risk of stroke is largely a consequence of morbidities of diabetes, obesity, hypertension, and heart diseases. Incidence of stroke is directly proportional to body mass index. Adipose tissue stores energy as well as acts as an active endocrine organ, which secretes numerous humoral factors. Adiponectin and leptin are the commonest adipocytokines and have been invariably linked to the development of coronary heart disease and may be involved in the underlying biological mechanism of stroke. Leptin and adiponectin mediate proatherogenic and antiatherogenic responses, respectively, and hence, determining the plasma or serum levels of leptin and adiponectin alone or in combination may act as a novel prognostic biomarker for inflammation and atherosclerosis in stroke. This review addresses leptin- and adiponectin-mediated inflammatory mechanism in ischemic stroke and their potential as therapeutic targets.

Adiponectin gene variants and abdominal obesity in an Iranian population

INTRODUCTION

Waist-to-height ratio (WHtR) can be effective for the diagnosis of abdominal obesity and the risk of type 2 diabetes. The role of genetic factors in the development of obesity has been broadly recognized. Adiponectin's level is inversely correlated with body fat percentage and is reduced in obesity and type 2 diabetes. The aim of this study is to investigate the association between WHtR and adiponectin gene polymorphisms in Iranian population.

METHODS

This study was conducted on 610 subjects from two Iranian populations. Anthropometric characteristics were measured by routine methods. Blood samples were collected in tubes (3-5 mL) containing EDTA and were stored at 20 °C. After DNA extraction, genotyping was performed using PCR-RFLP technique.

RESULTS

There were statistically significant differences in genotype frequencies of -11391 G/A in centrally obese (WHtR >0.5) and noncentrally obese (WHtR ≤0.5) subjects (P value <0.044). In the former, the frequencies of GG and GA + AA genotypes were 89.4 and 10.6 %, respectively, while the frequencies of GG and GA + AA genotypes were 95.9 and 4.1 %, respectively, in noncentrally obese subjects.

CONCLUSIONS

The frequency of GG genotype was significantly increased in subjects with WHtR >0.5 compared to the other group. After adjustment for diabetes, abdominal obesity was significantly associated with the -11391 G/A polymorphism.

A novel insulin sensitivity index particularly suitable to measure insulin sensitivity during gestation

AIMS

Insulin resistance underlies the etiology of both type 2 diabetes and gestational diabetes. In pregnancy, insulin resistance is also associated with an unfavorable metabolic programming of the fetus, potentially contributing to a higher risk of obesity and type 2 diabetes in the offspring. To assess insulin sensitivity, several methods based on glucose and insulin levels during a 75-g oral glucose tolerance test (OGTT) exist. It is unclear how they perform during pregnancy, where physiologically altered metabolism could introduce a bias.

METHODS

In a cohort comprising 476 non-diabetic subjects undergoing OGTT and hyperinsulinemic-euglycemic clamp (HEC), we used cross-validation to develop an insulin sensitivity index also based on non-esterified fatty acids (NEFA) that could be more robust during pregnancy (NEFA-index). We tested commonly used OGTT-based indexes and the NEFA-index in a different cohort of 42 women during pregnancy and 1 year after delivery.

RESULTS

The Matsuda and OGIS index failed to detect lower insulin sensitivity during pregnancy as compared to the follow-up OGTT 1 year after delivery (p > 0.09). The new NEFA-index incorporating BMI, plasma insulin and NEFA, but not glucose, clearly indicated lower insulin sensitivity during pregnancy (p < 0.0001). In the non-pregnant cohort, this NEFA-index correlated well with the gold-standard HEC-based insulin sensitivity index, and outperformed other tested indexes for the prediction of HEC-measured insulin resistance.

CONCLUSIONS

This insulin/NEFA-based approach is feasible, robust, and could be consistently used to estimate insulin sensitivity also during pregnancy.

Association of Adiponectin Polymorphism with Metabolic Syndrome Risk and Adiponectin Level with Stroke Risk: A Meta-Analysis

Many previous studies have provided evidence that the ADIPOQ +45T>G polymorphism (rs2241766) might cause metabolic syndrome (MS). As a cardiovascular manifestation of MS, the incidence of stroke is associated with adiponectin; however, the results remain controversial and inconsistent. Systematic searches of relevant studies published up to Dec 2014 and Jan 2016 on the ADIPOQ +45T>G polymorphism and the risk of MS and adiponectin levels and the risk of stroke, respectively, were conducted in MEDLINE and EMBASE. The odds ratio (OR) or risk ratio (RR) and their 95% confidence interval (95% CI) were extracted. Sixteen studies containing 4,113 MS cases and 3,637 healthy controls indicated a weak positive association between ADIPOQ +45 T>G and MS in the dominant genetic model (OR = 1.30, 95% CI = 1.03-1.65), which was also validated by stratified subgroup analyses. Twelve studies including 26,213 participants and 4,246 stroke cases indicated that 5 μg/ml increments in adiponectin level were not relevant to stroke risk (RR = 1.05, 95% CI = 1.00-1.10, P = 0.069). This study suggested a weak positive association of ADIPOQ +45T>G with MS and a strong association with metabolic-related disease. Additionally, adiponectin level was not a causal factor of increasing stroke risk.

Adiponectin, Leptin, and Fatty Acids in the Maintenance of Metabolic Homeostasis through Adipose Tissue Crosstalk

Metabolism research has made tremendous progress over the last several decades in establishing the adipocyte as a central rheostat in the regulation of systemic nutrient and energy homeostasis. Operating at multiple levels of control, the adipocyte communicates with organ systems to adjust gene expression, glucoregulatory hormone exocytosis, enzymatic reactions, and nutrient flux to equilibrate the metabolic demands of a positive or negative energy balance. The identification of these mechanisms has great potential to identify novel targets for the treatment of diabetes and related metabolic disorders. Herein, we review the central role of the adipocyte in the maintenance of metabolic homeostasis, highlighting three critical mediators: adiponectin, leptin, and fatty acids.

The diabetogenic action of statins - mechanisms and clinical implications

Treatment with statins has transformed primary and secondary prevention of cardiovascular disease (CVD), including thrombotic stroke. Evidence-based data demonstrate the benefits and safety of statin therapy and help to guide clinicians in the management of populations at high risk of CVD. Nevertheless, clinical trials, meta-analyses and observational studies highlight a 10-12% increase in new-onset diabetes mellitus (NODM) among patients receiving statins. The risk further increases with intensive therapy and among individuals with known risk factors for NODM. Mechanisms underpinning this effect are not yet fully understood; however, Mendelian randomization studies suggest that they are related to lowered activity of HMG-CoA reductase, the target of statin therapy. In vitro research indicates that statins potentially impair β-cell function and decrease insulin sensitivity but how these findings relate to patients is unknown. In the clinic, statins should be prescribed on the basis of CVD risk and individual patient characteristics. In addition, diet and lifestyle interventions should be emphasized to help mitigate the risk of NODM. Individuals who develop NODM while taking statins do not exhibit increased microvascular disease, which is reassuring. In diabetes mellitus of long duration, the effect of statins on glycaemic control is small and unlikely to be clinically important.

Central Administration of Galanin Receptor 1 Agonist Boosted Insulin Sensitivity in Adipose Cells of Diabetic Rats

Our previous studies testified the beneficial effect of central galanin on insulin sensitivity of type 2 diabetic rats. The aim of the study was further to investigate whether central M617, a galanin receptor 1 agonist, can benefit insulin sensitivity. The effects of intracerebroventricular administration of M617 on insulin sensitivity and insulin signaling were evaluated in adipose tissues of type 2 diabetic rats. The results showed that central injection of M617 significantly increased plasma adiponectin contents, glucose infusion rates in hyperinsulinemic-euglycemic clamp tests, GLUT4 mRNA expression levels, GLUT4 contents in plasma membranes, and total cell membranes of the adipose cells but reduced the plasma C-reactive protein concentration in nondiabetic and diabetic rats. The ratios of GLUT4 contents were higher in plasma membranes to total cell membranes in both nondiabetic and diabetic M617 groups than each control. In addition, the central administration of M617 enhanced the ratios of pAkt/Akt and pAS160/AS160, but not phosphorylative cAMP response element-binding protein (pCREB)/CREB in the adipose cells of nondiabetic and diabetic rats. These results suggest that excitation of central galanin receptor 1 facilitates insulin sensitivity via activation of the Akt/AS160 signaling pathway in the fat cells of type 2 diabetic rats.

Prevalence, Risk Factors, and Genetic Traits in Metabolically Healthy and Unhealthy Obese Individuals

Objective. To assess prevalence of metabolically healthy individuals among patients with abdominal obesity (AO) and to determine phenotype and potential genetic traits associated with a benign metabolic status. Methods. 503 AO patients without cardiovascular diseases were examined. Waist circumference (WC), BMI, blood pressure, plasma glucose and serum insulin levels, HOMA-IR, lipid profile, and adiponectin (AN) and leptin (LEP) concentrations in serum were measured. Polymorphisms A19G and Q223R of the LEP and LEP receptor gene, and G276T and T45G of the AN gene were investigated. Results. 91.3% of patients were metabolically unhealthy obese (MUO), and 8.7% metabolically healthy obese (MHO). MHO patients were younger, and had lesser BMI and WC, while duration of obesity, frequency, and duration of physical training were greater than MUO patients (p < 0.05). In MHO and MUO patients distribution of the G19G, G19A, and A19A genotypes of the LEP gene and G276G, G276T, and T276T genotypes of AN gene did not differ. The Т45Т genotype was associated with increase of metabolic disorders' risk for patients with АО (OR = 2.331; 95%  CI = 1.121 ÷ 5.132). Conclusions. Prevalence of MHO individuals among patients with AO is low. Benign metabolic status was associated with younger age, lower waist circumference, and higher physical activity, shorter duration of obesity, and G45G adiponectin genotype carriage.

Association Between Single Nucleotide Polymorphism +276G > T (rs1501299) in ADIPOQ and Endometrial Cancer

Current literature gives evidence of an indisputable role adiponectin plays in adipose tissue metabolism and obesity-related diseases. Moreover, latest research efforts focus on linking genetic markers of this adipocytokine's gene (ADIPOQ) with cancer. Aim of this study was to determine the genotype distribution of single nucleotide polymorphism +276G > T (rs1501299) in ADIPOQ and an attempt to identify the impact this polymorphism exerts on endometrial cancer risk in obese females. The test group comprised 90 women treated surgically for endometrial cancer between 2000 and 2012 in the Department of Surgical & Endoscopic Gynecology and Gynecologic Oncology, Polish Mothers' Memorial Hospital - Research Institute, Lodz, Poland. 90 individuals treated in the parallel period for uterine fibroids constituted the control group. Patients within both groups were stratified according to BMI into: lean, overweight and obese subjects. Statistical analysis was performed between two major groups and, furthermore, within the abovementioned subgroups. The analysis revealed that allele G of the investigated polymorphism in obese women with endometrial cancer is significantly more frequent, and allele T is significantly less frequent than in lean controls. However, no significant correlation was observed between the polymorphism and endometrial cancer in lean and overweight females. Single nucleotide polymorphism +276G > T (rs1501299) in ADIPOQ may be considered to be a risk factor of endometrial cancer. Further research on SNP in EC is warranted to obtain more conclusive outcomes.