Associations between two single-nucleotide polymorphisms (rs1801278 and rs2943641) of insulin receptor substrate 1 gene and type 2 diabetes susceptibility: a meta-analysis

Genetic and inflammatory factors underlying gestational diabetes mellitus: a review

Gestational diabetes mellitus (GDM) poses a significant global health concern, impacting both maternal and fetal well-being. Early detection and treatment are imperative to mitigate adverse outcomes during pregnancy. This review delves into the pivotal role of insulin function and the influence of genetic variants, including SLC30A8, CDKAL1, TCF7L2, IRS1, and GCK, in GDM development. These genetic variations affect beta-cell function and insulin activity in crucial tissues, such as muscle, disrupting glucose regulation during pregnancy. We propose a hypothesis that this variation may disrupt zinc transport, consequently impairing insulin production and secretion, thereby contributing to GDM onset. Furthermore, we discussed the involvement of inflammatory pathways, such as TNF-alpha and IL-6, in predisposing individuals to GDM. Genetic modulation of these pathways may exacerbate glucose metabolism dysregulation observed in GDM patients. We also discussed how GDM affects cardiovascular disease (CVD) through a direct correlation between pregnancy and cardiometabolic function, increasing atherosclerosis, decreased vascular function, dyslipidemia, and hypertension in women with GDM history. However, further research is imperative to unravel the intricate interplay between inflammatory pathways, genetics, and GDM. This understanding is pivotal for devising targeted gene therapies and pharmacological interventions to rectify genetic variations in SLC30A8, CDKAL1, TCF7L2, IRS1, GCK, and other pertinent genes. Ultimately, this review offers insights into the pathophysiological mechanisms of GDM, providing a foundation for developing strategies to mitigate its impact.

Semaglutide alleviates gut microbiota dysbiosis induced by a high-fat diet

This study investigated the effects of semaglutide (Sema) on the gut microbiota of obese mice induced with high-fat diet (HFD). Male C57BL/6 J mice aged 6 weeks were enrolled and randomly distributed to four groups, which were provided with a normal control diet (NCD,NCD + Sema) and a 60% proportion of a high-fat diet (HFD,HFD + Sema), respectively. HFD was given for 10 weeks to develop an obesity model and the intervention was lasted for 18 days. The results showed semaglutide significantly reduced body weight gain, areas under the curve (AUC) of glucose tolerance test and insulin resistance test, as well as adipose tissue weight in mice. Semaglutide effectively reduced lipid deposition and lipid droplet formation in the liver of obese mice, and regulated the expression of genes related to abnormal blood glucose regulation. Additionally, semaglutide influenced the composition of gut microbiota, mitigating the microbial dysbiosis induced by a high-fat diet by impacting the diversity of the gut microbiota. After the high-fat diet intervention, certain strains such as Akkermansia, Faecalibaculum, and Allobaculum were significantly decreased, while Lachnospiraceae and Bacteroides were significantly increased. However, the application of semaglutide restored the lost flora and suppressed excessive bacterial abundance. Moreover, semaglutide increased the content of tight junction proteins and repaired the damage to intestinal barrier function caused by the high-fat diet intervention. Furthermore, correlation analysis revealed inverse relationship among Akkermansia levels and weight gain, blood glucose levels, and various obesity indicators. Correlation analysis also showed that Akkermansia level was negatively correlated with weight gain, blood glucose levels and a range of obesity indicators. This phenomenon may explain the anti-obesity effect of semaglutide, which is linked to alterations in gut microbiota, specifically an increase in the abundance of Akkermansia. In summary, our findings indicate that semaglutide has the potential to alleviate gut microbiota dysbiosis, and the gut microbiota may contribute to the obesity-related effects of this drug.

Association of IRS-1 and IRS-2 polymorphisms with predisposition to type-2 diabetes (T2D): a meta-analysis and trial sequential analysis

Background: Insulin Receptor Substrate (IRS) molecules play a major role in insulin signalling, and single nucleotide polymorphisms in the IRS-1 (rs1801278) and IRS-2 (rs1805097) gene has been associated with the predisposition to the development of type-2 diabetes (T2D) in some population. However, the observations remain contradictory. Discrepancies in the results have been attributed to several factors, and consideration of a smaller sample size is one of them. To reach a valid conclusion, we performed a meta-analysis of the genetic association between IRS-1 (rs1801278) and IRS-2 (rs1805097) polymorphism with a predisposition to T2D. Materials and Methods: The literature search was performed in different databases such as PubMed, Science Direct, and Scopus. All relevant articles were screened and based in inclusion and exclusion criteria eligible reports were identified. Baseline characteristics, genotype and allele frequencies were extracted from the eligible reports. The meta-analysis was performed by comprehensive meta-analysis software v3.3.070 and odds ratios, 95% confidence interval and probability values were calculated to find out association of IRS-1 and IRS-2 polymorphisms with rhinitis. Results: A total of seven studies comprising 1287 cases and 1638 control were considered for the present meta-analysis for the association of IRS-1 (rs1801278) polymorphism with T2D, and no significant association was observed. For IRS-2 (rs1805097) polymorphism, data from eight cohorts (cases: 1824, controls: 1786) were considered. The heterozygous genetic comparison models revealed a significant protective association against T2D predisposition (p = 0.017, OR = 0.841, 95% CI = 0.729 to 0.970). The trial sequential analysis revealed the requirement of additional case-control studies to draw a definitive conclusion for IRS-1 polymorphism. Conclusions: IRS-2 rs1805097 heterozygotes are protected from T2D development. However, IRS-1 (rs1801278) is not associated with a subject's proclivity for T2D.

The genetic interactions between non-alcoholic fatty liver disease and cardiovascular diseases

The ongoing debate on whether non-alcoholic fatty liver disease (NAFLD) is an active contributor or an innocent bystander in the development of cardiovascular disease (CVD) has sparked interests in understanding the common mediators between the two biologically distinct entities. This comprehensive review identifies and curates genetic studies of NAFLD overlapping with CVD, and describes the colinear as well as opposing correlations between genetic associations for the two diseases. Here, CVD described in relation to NAFLD are coronary artery disease, cardiomyopathy and atrial fibrillation. Unique findings of this review included certain NAFLD susceptibility genes that possessed cardioprotective properties. Moreover, the complex interactions of genetic and environmental risk factors shed light on the disparity in genetic influence on NAFLD and its incident CVD. This serves to unravel NAFLD-mediated pathways in order to reduce CVD events, and helps identify targeted treatment strategies, develop polygenic risk scores to improve risk prediction and personalise disease prevention.

COBLL1 and IRS1 Gene Polymorphisms and Placental Expression in Women with Gestational Diabetes

Gestational diabetes mellitus (GDM) is carbohydrate intolerance in pregnant women leading to various complications. Currently, there is a search for factors predisposing to GDM. Among them are genetic polymorphisms of genes involved in insulin secretion as well as carbohydrate metabolism. Due to the similar pathogenesis of GDM to type 2 diabetes (T2DM), genetic polymorphisms associated with T2DM are considered. The aim of this study was to examine the associations between the COBLL1 rs7607980 T > C and IRS1 rs2943641 T > C gene polymorphisms and the risk of GDM as well as selected clinical parameters in women with GDM. Additionally, we examined the expression of these genes in the placenta of women with and without GDM in correlation with selected clinical parameters. This study included 328 pregnant women with normal glucose tolerance (NGT) and 251 pregnant women with GDM diagnosed on the basis of a 75 g oral glucose tolerance test (OGTT) at 24−28 weeks gestation. There were no statistically significant differences in the distribution of IRS1 rs2943641 gene polymorphisms between women with GDM and pregnant women with NGT. In the GDM group, we observed a decreased frequency of COBLL1 rs7607980 CC homozygous women (CC vs. TC+TT, p = 0.048); however, there was no statistically significant difference in the frequency of alleles between women with GDM and the control group. There were no statistically significant associations between COBLL1 rs7607980 gene polymorphism and clinical parameters in women with GDM. In GDM women with the IRS1 rs2943641 TT genotype, fasting glucose levels were significantly higher than in women with CC and TC genotypes. There was no statistically significant difference in the expression of COBLL1 and IRS1 genes in the placenta between women with GDM and healthy women. There were no statistically significant correlations between COBLL1 gene expression in the placenta and clinical parameters. The expression of IRS1 correlated significantly with an increase in BMI during pregnancy. The results of this study suggest that COBLL1 rs7607980 and IRS1 rs2943641 gene polymorphisms are not significant risk factors for GDM in our population. The IRS1 TT genotype may be associated with higher fasting glucose levels in women with GDM. Expression of the IRS1 gene in the placenta positively correlates with an increase in BMI during pregnancy in women with GDM.

Association of Insulin Receptor Substrate-1 Gene Polymorphism (rs1801278) with Alzheimer’s Disease

Background: Alzheimer’s disease (AD) is the most common form of dementia. AD is also the leading cause of morbidity and mortality due to dementia worldwide. It has been shown that AD is associated with type 2 diabetes mellitus (T2DM) and brain insulin resistance. Rs1801278 is a polymorphism in insulin receptor substrate-1 (IRS-1) gene which changes the amino acid Arg972. This polymorphism has been found to be associated with susceptibility to AD in some populations. Objective: In the present study, our aim was to investigate the association of Arg972 IRS-1 (rs1801278) gene polymorphism and late-onset Alzheimer’s disease (LOAD) in an Iranian population. Methods: In this case-control study, 150 patients with LOAD and 150 unrelated healthy controls were recruited. Polymerase chain reaction (PCR) was performed to amplify a DNA segment of 263 base-pair (bp) length containing the single nucleotide polymorphism (SNP). The PCR product was then incubated with MvaI restriction enzyme to undergo enzymatic cleavage. Electrophoresis was thereafter carried out using agarose gel and DNA safe stain. The gel was ultimately visualized under a UV trans-illuminator. Allelic and genotypic frequencies were then compared. Results: A allele (mutant) of the gene was significantly associated with the risk of AD after adjustment for sex and age (p = 0.04, adjusted OR:1.77, 95% CI:1.00–3.11). Only AA genotype (mutant homozygote) was significantly associated with the risk of AD after adjustment for sex and age (p = 0.01, adjusted OR:2.39, 95% CI:1.22–4.66). Conclusion: SNP rs1801278 is significantly associated with the risk of developing AD in the studied Iranian population.

Association of IRS1 (Gly972Arg) and IRS2 (Gly1057Asp) genes polymorphisms with OSA and NAFLD in Asian Indians

AIM AND OBJECTIVE

The aim of the study was to investigate the relationships between insulin receptor substrate (IRS) 1 (Gly972Arg) and IRS2 (Gly1057Asp) genes with obstructive sleep apnea (OSA) and non-alcoholic fatty liver disease (NAFLD) in Asian Indians.

METHOD

A total of 410 overweight/obese subjects (130 with OSA with NAFLD, 100 with OSA without NAFLD, 95 without OSA and with NAFLD and 85 without OSA and without NAFLD) were recruited. Degree of NAFLD was based on liver ultrasound and of OSA on overnight polysomnography. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism and confirmed by gene sequencing.

RESULT

Mean values of blood pressure, body fat markers, blood glucose, lipids, liver function, and markers of insulin resistance were significantly increased in OSA and NAFLD subjects (p<0.05). In addition, according to age (years) categories, blood pressure, blood glucose, lipids, obesity markers, and markers of insulin resistance were significantly higher in 45-60 years group as compared to 20-45 years group (p<0.05). In IRS1 gene, the genotype frequency (%) of Arg/Arg was significantly higher in NAFLD and OSA subjects. In addition, Gly/Arg genotype of IRS1 gene was associated with significantly higher body mass index, fat mass, %body fat, triglycerides, cholesterol, alkaline phosphate, aspartate transaminase, fasting insulin and HOMA-IR levels in OSA and NAFLD subjects. No significant difference in genotype frequencies of IRS2 was observed between four groups. Further we found that subjects carrying IRS1 Gly/Arg (OR 4.49, 95% C.I. 1.06-12.52, p = 0.002) genotype possess a much higher risk of OSA and NAFLD compared to IRS2 Gly/Asp (OR 1.01, 95% C.I. 0.8-2.56, p = 0.05). In sub group analysis of IRS1 Gly/Arg have significant differences between the mild, moderate and severe group (P<0.05). In addition, patients with the 'Gly' allele were inclined to develop more severe OSA.

CONCLUSION

We concluded that Asian Indian subject carrying the allele Gly972Arg polymorphism of IRS1 is predisposed to develop OSA and NAFLD.

The Association between Maternal/Fetal Insulin Receptor Substrate 1 Gene Polymorphism rs1801278 and Gestational Diabetes Mellitus in a Chinese Population

OBJECTIVES

Insulin receptor substrate 1 (IRS1) is a crucial factor in the insulin signaling pathway. IRS1 gene polymorphism rs1801278 in mothers has been reported to be associated with gestational diabetes mellitus (GDM). However, it is not clear whether IRS1 gene polymorphism rs1801278 in fetuses is associated with their mothers' GDM morbidity. The purpose of this study is to analyze the association between maternal, fetal, or maternal/fetal IRS1 gene polymorphism rs1801278 and GDM risk.

DESIGN

The study was a single-center, prospective cohort study. In total, 213 pairs of GDM mothers/fetuses and 191 pairs of control mothers/fetuses were included in this study. They were recruited after they underwent oral glucose tolerance test during 24-28 weeks of gestation and followed up until delivery. All participants received the conventional interventions (diet and exercise), and no special therapy except routine treatment.

METHODS

A total of 213 pairs of GDM mothers/fetuses and 191 pairs of normal blood glucose pregnant mothers/fetuses were ge-notyped using PCR and DNA sequencing from January 2015 to September 2016. Maternal/fetal IRS1 gene polymorphism rs1801278 was analyzed and compared between 2 groups.

RESULTS

There were no significant differences in the frequency of individual mothers' or fetuses' IRS1 rs1801278 polymorphisms between 2 groups; if both the mothers and fetuses carried A allele, significantly lower GDM morbidity was observed in the mothers.

LIMITATIONS

The sample size was relatively small as a single-center study.

CONCLUSIONS

Our study suggested that maternal/fetal rs1801278 polymorphism of IRS1 is a modulating factor in GDM; both mothers/fetuses carrying the A allele of rs1801278 may protect the mothers against the development of GDM.

ASSOCIATION OF IRS1 GLY971ARG GENE POLYMORPHISM WITH INSULIN RESISTANCE IN IRANIAN NEWLY DIAGNOSED DIABETIC ADULTS

Context

Insulin receptor substrate-1 (IRS-1) has an important role in insulin signaling and the common Gly971Arg polymorphism is related to type 2 diabetes (T2D). IRS-1 Gly971Arg polymorphism can modify tyrosine phosphorylation at a specific site of IRS-1 and may have a critical role in the development of insulin resistance (IR).

Objective

The purpose of this study was to investigate the association between this polymorphism and IR in Iranian patients with newly-diagnosed type 2 diabetes.

Design

The study was conducted on 114 individuals with newly-diagnosed T2D and 118 healthy matched controls, aged 20-80 years. Fasting blood glucose and insulin were measured by the enzymatic method and enzyme-linked immunosorbent assay, respectively. Insulin-resistance was calculated by homeostasis model assessment estimated-insulin resistance (HOMA-IR). The gene polymorphism was examined by polymerase chain reaction-restriction fragment length polymorphism.

Results

There are significant differences between IRS1 Gly971Arg polymorphism and studied individuals (P<0.0001). The findings showed that the risk of developing T2D in individuals who had R-alleles was 3.74 folds higher than those without R-alleles. However, IRS1 Gly971Arg polymorphism was not associated with high HOMA-IR, high BMI and familial history of diabetes.

Conclusions

Even though there was not a significant relationship between IRS-1 G971R polymorphism with insulin resistance and high BMI, this polymorphism was correlated to newly-diagnosed diabetic patients. Thus, the evaluation of IRS-1 G971R polymorphism may be helpful for predicting T2D new cases.

Association of IRS1 genetic variants with glucose control and insulin resistance in type 2 diabetic patients from Bosnia and Herzegovina

Background Previous studies reported conflicting results regarding association of insulin receptor substrate 1 (IRS1) gene variation with type 2 diabetes (T2D) and insulin resistance (IR) in different ethnic groups. We examined the association of rs7578326, rs2943641, and rs4675095 in the IRS1 gene with T2D and related traits in a population from Bosnia and Herzegovina, which is one of the European countries with the highest T2D prevalence of 12.5%. Methods Our study included 390 T2D patients and 252 control subjects. Biochemical parameters, including fasting glucose (FG), fasting insulin (FI), homeostasis model assessment insulin resistance index (HOMA-IR), and HbA1c were measured in all participants. Genotyping analysis was performed by Mass Array Sequenom iPlex platform. Results Our results demonstrated that rs7578326 and rs4675095 variants were associated with increased FG levels. The rs7578326 was also associated with higher FI, HOMA-IR (B = 0.08, 95% CI [0.01, 0.15], padd = 0.025; B = 0.079, 95% CI [0.006, 0.150], padd = 0.033, respectively) in T2D, and with HbA1c (B = 0.034, 95% CI [0.003, 0.065], pdom = 0.035) in non-drug-treated T2D. In contrast, rs2943641 C allele was associated with lower FG levels in control subjects (B = -0.17, 95% CI [-0.03, -0.002], padd = 0.030) and HbA1c (B = 0.03, 95% CI [0.002, 0.06], pdom = 0.040) in non-drug-treated T2D. Conclusions We report the association between common variants in IRS1 gene with insulin resistance, glucose, and HbA1c levels in Bosnia and Herzegovina's population.

Clinical effect of emergency cervical cerclage and elective cervical cerclage on pregnancy outcome in the cervical-incompetent pregnant women

PURPOSE

To compare the clinical effect of emergency cervical cerclage and elective cervical cerclage on pregnancy outcome in the cervical-incompetent pregnant women.

METHODS

Literature was searched from the databases of Pubmed, Embase and Google scholar. The fixed or random effects model was used to calculate pooled risk ratios on the basis of heterogeneity. Meta-regression, sensitive analysis, subgroup analysis, and publication bias assessment were also conducted to confirm the results according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2009.

RESULTS

The meta-analysis results showed that there were significant associations between cerclage operations and pregnancy outcomes in gestation age, birth weight, and PROM rate. Gestation age was significantly higher in women with elective cerclage than those with emergency cerclage, and birth weight was significantly higher in newborns for the elective group as compared with emergency group. The rate of PROM in elective group was lower than emergency group. However, there were no differences between the emergency cerclage group and the elective cerclage group regarding the rate of vaginal delivery.

CONCLUSIONS

This meta-analysis suggests that emergency cerclage has lower gestation age and birth weight than elective cerclage, and it increases the risk of PROM. Further well-designed studies are warranted to confirm these results.

Gene-Diet Interactions in Type 2 Diabetes: The Chicken and Egg Debate

Consistent evidence from both experimental and human studies indicates that Type 2 diabetes mellitus (T2DM) is a complex disease resulting from the interaction of genetic, epigenetic, environmental, and lifestyle factors. Nutrients and dietary patterns are important environmental factors to consider in the prevention, development and treatment of this disease. Nutritional genomics focuses on the interaction between bioactive food components and the genome and includes studies of nutrigenetics, nutrigenomics and epigenetic modifications caused by nutrients. There is evidence supporting the existence of nutrient-gene and T2DM interactions coming from animal studies and family-based intervention studies. Moreover, many case-control, cohort, cross-sectional cohort studies and clinical trials have identified relationships between individual genetic load, diet and T2DM. Some of these studies were on a large scale. In addition, studies with animal models and human observational studies, in different countries over periods of time, support a causative relationship between adverse nutritional conditions during in utero development, persistent epigenetic changes and T2DM. This review provides comprehensive information on the current state of nutrient-gene interactions and their role in T2DM pathogenesis, the relationship between individual genetic load and diet, and the importance of epigenetic factors in influencing gene expression and defining the individual risk of T2DM.