Association of variants in PPARγ², IGF2BP2, and KCNQ1 with a susceptibility to gestational diabetes mellitus in a Korean population

Advancements in Nutritional Strategies for Gestational Diabetes Management: A Systematic Review of Recent Evidence

Gestational diabetes mellitus (GDM) is defined as hyperglycaemia first detected at any time during pregnancy with values lower than those determined by the WHO for diabetes diagnosis in adults. This pathology, with a worldwide prevalence of 13.4%, causes significant maternal and foetal risks. The first line of treatment consists of maintaining normo-glycaemia through an adequate diet and lifestyle changes. The aim is to synthesize the scientific evidence updating the nutritional recommendations for the effective management of GDM. A systematic review of the scientific literature was conducted following the PRISMA guidelines. Randomized clinical trials published within the last five years and providing information on nutritional recommendations to achieve an effective management of gestational diabetes were selected. The databases searched were PubMed, the WOS Core Collection, SCOPUS, and CINAHL, using the MeSH terms: "Diabetes, Gestational"; "Nutrition Assessment (nutrition*)"; "Diet"; "Eating"; and "Food"; with the Boolean operators "AND" and "OR". The PEDro scale (Physiotherapy Evidence Database) was used to assess the scientific quality of the studies, with a mean score of 8.9, indicating an average good scientific quality. Results: A total of 809 papers were collected, of which, after applying the inclusion and exclusion criteria, 14 randomized clinical trials were selected. Probiotic supplementation and co-supplementation with vitamin D have been found to be the most beneficial options for both mothers with GDM and neonates, but the most effective regimens are not known. Diets enriched with extra virgin olive oil (EVOO) and oat bran, as well as some recommendations focused on carbohydrates also seem effective, as well as diets designed for this group of women with GDM such as "CHOICE". Conclusions: Although there are numerous proposals that have been published in recent years focused on the diet of women with GDM in order to improve their results and those of their children, it is the supplementation with probiotics and the co-supplementation with vitamin D that is most agreed upon as beneficial; however, more research is needed into which protocols are most effective. Other proposals that could also be beneficial should be further studied.

A Clinical Update on Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) traditionally refers to abnormal glucose tolerance with onset or first recognition during pregnancy. GDM has long been associated with obstetric and neonatal complications primarily relating to higher infant birthweight and is increasingly recognized as a risk factor for future maternal and offspring cardiometabolic disease. The prevalence of GDM continues to rise internationally due to epidemiological factors including the increase in background rates of obesity in women of reproductive age and rising maternal age and the implementation of the revised International Association of the Diabetes and Pregnancy Study Groups' criteria and diagnostic procedures for GDM. The current lack of international consensus for the diagnosis of GDM reflects its complex historical evolution and pragmatic antenatal resource considerations given GDM is now 1 of the most common complications of pregnancy. Regardless, the contemporary clinical approach to GDM should be informed not only by its short-term complications but also by its longer term prognosis. Recent data demonstrate the effect of early in utero exposure to maternal hyperglycemia, with evidence for fetal overgrowth present prior to the traditional diagnosis of GDM from 24 weeks' gestation, as well as the durable adverse impact of maternal hyperglycemia on child and adolescent metabolism. The major contribution of GDM to the global epidemic of intergenerational cardiometabolic disease highlights the importance of identifying GDM as an early risk factor for type 2 diabetes and cardiovascular disease, broadening the prevailing clinical approach to address longer term maternal and offspring complications following a diagnosis of GDM.

KCNJ11 and KCNQ1 Gene Polymorphisms and Placental Expression in Women with Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) represents carbohydrate intolerance in pregnant women. The pathogenesis of GDM is very complex, but abnormalities in insulin production and secretion underlie the disease. Potassium channels play an important role in insulin production and secretion. The family of potassium channels includes (among others) the potassium inwardly rectifying channel, subfamily J, member 11 (KCNJ11) and voltage-gated K+ channel (KCNQ1). The aim of the study was to examine the distribution of the KCNJ11 rs5219 and KCNQ1 rs151290 and rs2237892 gene polymorphisms in women with GDM and pregnant women with normal carbohydrate tolerance, to verify whether these polymorphisms are risk factors for GDM. This study included 204 Caucasian pregnant women with GDM and 207 pregnant women with normal glucose tolerance (NGT) from the West Pomeranian region of Poland. The diagnosis of GDM was based on a 75 g oral glucose tolerance test (OGTT) at 24–28 weeks gestation. There were no statistically significant differences in distribution of the KCNJ11 rs5219 and KCNQ1 rs151290 and rs2237892 gene polymorphisms between women with GDM and pregnant women with normal carbohydrate tolerance. Moreover, there were no statistically significant associations between the studied genotypes and the selected clinical parameters in women with GDM. The results of our study suggest that the KCNJ11 rs5219 and KCNQ1 rs2237892 and rs151290 gene polymorphisms are not significant risk factors associated with the development of GDM in our population. There were also no differences in the expression of KCNJ11 and KCNQ1 genes in the placenta of women with GDM and normal carbohydrate tolerance. However, an association between KCNJ11 gene expression in placenta and APGAR score in newborns was found.

The role of insulin-like growth factor 2 mRNA binding proteins in female reproductive pathophysiology

Insulin-like growth factor 2 (IGF2) mRNA binding proteins (IMPs) family belongs to a highly conserved family of RNA-binding proteins (RBPs) and is responsible for regulating RNA processing including localization, translation and stability. Mammalian IMPs (IMP1-3) take part in development, metabolism and tumorigenesis, where they are believed to play a major role in cell growth, metabolism, migration and invasion. IMPs have been identified that are expressed in ovary, placenta and embryo. The up-to-date evidence suggest that IMPs are involved in folliculogenesis, oocyte maturation, embryogenesis, implantation, and placentation. The dysregulation of IMPs not only contributes to carcinogenesis but also disturbs the female reproduction, and may participate in the pathogenesis of reproductive diseases and obstetric syndromes, such as polycystic ovary syndrome (PCOS), pre-eclampsia (PE), gestational diabetes mellitus (GDM) and gynecological tumors. In this review, we summarize the role of IMPs in female reproductive pathophysiology, and hope to provide new insights into the identification of potential therapeutic targets.

Genomics and Epigenomics of Gestational Diabetes Mellitus: Understanding the Molecular Pathways of the Disease Pathogenesis

One of the most common complications during pregnancy is gestational diabetes mellitus (GDM), hyperglycemia that occurs for the first time during pregnancy. The condition is multifactorial, caused by an interaction between genetic, epigenetic, and environmental factors. However, the underlying mechanisms responsible for its pathogenesis remain elusive. Moreover, in contrast to several common metabolic disorders, molecular research in GDM is lagging. It is important to recognize that GDM is still commonly diagnosed during the second trimester of pregnancy using the oral glucose tolerance test (OGGT), at a time when both a fetal and maternal pathophysiology is already present, demonstrating the increased blood glucose levels associated with exacerbated insulin resistance. Therefore, early detection of metabolic changes and associated epigenetic and genetic factors that can lead to an improved prediction of adverse pregnancy outcomes and future cardio-metabolic pathologies in GDM women and their children is imperative. Several genomic and epigenetic approaches have been used to identify the genes, genetic variants, metabolic pathways, and epigenetic modifications involved in GDM to determine its etiology. In this article, we explore these factors as well as how their functional effects may contribute to immediate and future pathologies in women with GDM and their offspring from birth to adulthood. We also discuss how these approaches contribute to the changes in different molecular pathways that contribute to the GDM pathogenesis, with a special focus on the development of insulin resistance.

GST T1, M1, and IRS-1 G972R Genetic Variants Association to Gestational Diabetes Mellitus (GDM) in Egyptian Women: Linkage to Maternal Hyperglycemia

BACKGROUND

Gestational Diabetes Mellitus (GDM) shares in part the pathogenic mechanisms of multiple genetic interactions. Some of the T2D susceptibility genes are encountered in association with GDM.

OBJECTIVE

We aimed to investigate GST T1, M1, and G972R IRS-I gene polymorphisms with the risk of developing GDM.

METHODS

In this randomized case-control study, pregnant women with GDM were genotyped by PCR analysis for glutathione s-transferase-T1, M1 variant polymorphisms. RFLP was done for the G972R IRS 1 gene. Their newborns were additionally assayed for the whole of the clinical, laboratory, and genetic aspects.

RESULTS

The T allele IRS-1rs1801278 TT genotype was more frequently detected in GDM mothers in comparison to healthy control ones [for TT homozygous variant; OR(CI 95%): 2.05(1.09-3.87, p: 0.025)]. Furthermore, GST T1 null was significantly presented in GDM mothers than those of control mothers [OR (CI95%: 0.29 (0.084-1.02), p:0.04]. Added to the significant correlation of glycemic indices to clinical parameters of infants born to GDM, the M1-null genotype of GST was significantly correlated (p<0.05) to abnormal values of respiratory rates and 1 minute-APGAR score noted for extra NICU care.

CONCLUSION

Our results suggested that GST T1null and IRS-1 TT genotypic variants were claimed for GDM development among Egyptian women with a possible impact on their newly born infants.

Gestational Diabetes Mellitus: The Genetic Susceptibility Behind the Disease

Gestational diabetes mellitus (GDM), a type of pregnancy-specific glucose intolerance or hyperglycemia, is one of the most common metabolic disorders in pregnant women with 16.9% of the global prevalence of gestational hyperglycemia. Not only are women with GDM likely to develop T2DM, but their children are also at risk for birth complications or metabolic disease in adulthood. Therefore, identifying the potential risk factors for GDM is very important in the prevention and treatment of GDM. Previous studies have shown that genetic predisposition is an essential component in the occurrence of GDM. In this narrative review, we describe the role of polymorphisms in different functional genes associated with increased risk for GDM, and available evidence on genetic factors in the risk of GDM is summarized and discussed.

Lack of association between IGF2BP2 rs4402960 polymorphism and gestational diabetes mellitus: a case-control study, meta-analysis and trial sequential analysis

Background: It is well known that insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) rs4402960 polymorphism is associated with Type 2 diabetes mellitus, which has a shared genetic background with gestational diabetes mellitus (GDM). Previous studies have yielded controversial results about the link between IGF2BP2 rs4402960 polymorphism and GDM risk. Thus, a meta-analysis was performed to obtain more conclusive results.

Methods: Clinical and genotype data were determined for 305 GDM and 1216 healthy participants recruited. Eligible studies were retrieved in PubMed, Web of science, EMBASE, and Scopus. Odds ratios (ORs) with 95% confidence intervals (CIs) were utilized to evaluate the relationship between IGF2BP2 polymorphisms and GDM susceptibility in five genetic models. The subgroup stratified analysis and trial sequential analysis (TSA) were performed.

Results: In this case–control study, no significant association was revealed between IGF2BP2 polymorphism and GDM (P>0.05). When combined with the previous studies in the meta-analysis, there was no statistical association between IGF2BP2 polymorphism and GDM (allele model: OR = 1.01, 95% CI = 0.86–1.18; dominant model: OR = 1.00, 95% CI = 0.81–1.24; recessive model: OR = 1.08, 95% CI = 0.91–1.29; heterozygous model: OR = 0.99, 95% CI = 0.80–1.24; homozygous model: OR = 1.06, 95% CI = 0.78–1.42). No association was observed in five genetic models in each subgroup. TSA indicated sufficient proof of such null association in the overall population.

Conclusions: This meta-analysis provides sufficient statistical evidence indicating null association between IGF2BP2 rs4402960 polymorphism and GDM risk.

The role of IGF2BP2, an m6A reader gene, in human metabolic diseases and cancers

The human insulin-like growth factor 2 (IGF2) mRNA binding proteins 2 (IGF2BP2/IMP2) is an RNA-binding protein that regulates multiple biological processes. Previously, IGF2BP2 was thought to be a type 2 diabetes (T2D)-associated gene. Indeed IGF2BP2 modulates cellular metabolism in human metabolic diseases such as diabetes, obesity and fatty liver through post-transcriptional regulation of numerous genes in multiple cell types. Emerging evidence shows that IGF2BP2 is an N6-methyladenosine (m6A) reader that participates in the development and progression of cancers by communicating with different RNAs such as microRNAs (miRNAs), messenger RNAs (mRNAs) and long non-coding RNAs (lncRNAs). Additionally, IGF2BP2 is an independent prognostic factor for multiple cancer types. In this review, we summarize the current knowledge on IGF2BP2 with regard to diverse human metabolic diseases and its potential for cancer prognosis.

Polymorphic genetic markers and how they are associated with clinical and metabolic indicators of type 2 diabetes mellitus in the Kazakh population

Background

Type 2 diabetes mellitus is a serious public health problem worldwide. The aim of the study was to analyze the relationship of eight polymorphic gene variants with the development of clinical-metabolic rates of type 2 diabetes mellitus inside Kazakh population.

Materials and methods

139 patients with type 2 diabetes mellitus and 100 patients in the control group were examined. Genotyping of polymorphisms of candidate genes was carried out on a next generation QuantStudio 12 K Flex unit.

Results

Gene TCF7L2 locus rs7901695 and rs7903146, gene KCNQ1 locus rs2237892, rs7756992, and gene CDKAL1 locus rs7754840 demonstrated statistically significant associations with glucose metabolism, lipid profile and body mass index (BMI) in type 2 DM inside the population. Statistically significant difference in anthropometric and biochemical measures of rs17584499, rs4712523 and rs163184 has not been revealed.

Conclusions

Genetic polymorphisms that influence pancreatic gland beta-cells insulin release and secretion associate with metabolic and anthropometric measures definitive for type 2 DM in Kazakh population.

Nuclear receptors, gestational metabolism and maternal metabolic disorders

Normal pregnancy is characterised by a gradual alteration in metabolism that results in elevated serum bile acids, dyslipidaemia and impaired glucose tolerance in the third trimester. Nuclear receptors play important roles in regulating metabolic pathways that influence alterations in these parameters. There is evidence for altered function of FXR and LXR in gestation; these nuclear receptors play an integral role in bile acid and lipid homeostasis. There is some evidence for influence of clock genes in late pregnancy metabolic changes, and this may be linked to alterations in placental gene expression and function, thereby influencing fetal growth. This article will review the current data from human studies and investigation of animal models to illustrate the role of nuclear receptors (namely LXR, FXR, PPARs and clock genes) in gestational alterations in metabolism and the ways this may influence susceptibility to metabolic disorders of pregnancy such as gestational diabetes mellitus and intrahepatic cholestasis of pregnancy.

The Effects of Probiotic Supplementation on Genetic and Metabolic Profiles in Patients with Gestational Diabetes Mellitus: a Randomized, Double-Blind, Placebo-Controlled Trial

This study was carried out to evaluate the effects of probiotic supplementation on genetic and metabolic profiles in patients with gestational diabetes mellitus (GDM) who were not on oral hypoglycemic agents. This randomized, double-blind, placebo-controlled clinical trial was conducted in 48 patients with GDM. Participants were randomly divided into two groups to intake either probiotic capsule containing Lactobacillus acidophilus, Lactobacillus casei, Bifidobacterium bifidum, Lactobacillus fermentum (2 × 10⁹ CFU/g each) (n = 24) or placebo (n = 24) for 6 weeks. Probiotic intake upregulated peroxisome proliferator-activated receptor gamma (P = 0.01), transforming growth factor beta (P = 0.002) and vascular endothelial growth factor (P = 0.006), and downregulated gene expression of tumor necrosis factor alpha (P = 0.03) in peripheral blood mononuclear cells of subjects with GDM. In addition, probiotic supplementation significantly decreased fasting plasma glucose (β, - 3.43 mg/dL; 95% CI, - 6.48, - 0.38; P = 0.02), serum insulin levels (β, - 2.29 μIU/mL; 95% CI, - 3.60, - 0.99; P = 0.001), and insulin resistance (β, - 0.67; 95% CI, - 1.05, - 0.29; P = 0.001) and significantly increased insulin sensitivity (β, 0.009; 95% CI, 0.004, 0.01; P = 0.001) compared with the placebo. Additionally, consuming probiotic significantly decreased triglycerides (P = 0.02), VLDL-cholesterol (P = 0.02), and total-/HDL-cholesterol ratio (P = 0.006) and significantly increased HDL-cholesterol levels (P = 0.03) compared with the placebo. Finally, probiotic administration led to a significant reduction in plasma malondialdehyde (P < 0.001), and a significant elevation in plasma nitric oxide (P = 0.01) and total antioxidant capacity (P = 0.01) was observed compared with the placebo. Overall, probiotic supplementation for 6 weeks to patients with GDM had beneficial effects on gene expression related to insulin and inflammation, glycemic control, few lipid profiles, inflammatory markers, and oxidative stress.

Update on the genetic and epigenetic etiology of gestational diabetes mellitus: a review

Background

Many studies have been conducted on the genetic and epigenetic etiology of gestational diabetes mellitus (GDM) in the last two decades because of the disease’s increasing prevalence and role in global diabetes mellitus (DM) explosion. An update on the genetic and epigenetic etiology of GDM then becomes imperative to better understand and stem the rising incidence of the disease. This review, therefore, articulated GDM candidate genes and their pathophysiology for the awareness of stakeholders.

Main body (genetic and epigenetic etiology, GDM)

The search discovered 83 GDM candidate genes, of which TCF7L2, MTNR1B, CDKAL1, IRS1, and KCNQ1 are the most prevalent. Certain polymorphisms of these genes can modulate beta-cell dysfunction, adiposity, obesity, and insulin resistance through several mechanisms. Environmental triggers such as diets, pollutants, and microbes may also cause epigenetic changes in these genes, resulting in a loss of insulin-boosting and glucose metabolism functions. Early detection and adequate management may resolve the condition after delivery; otherwise, it will progress to maternal type 2 diabetes mellitus (T2DM) and fetal configuration to future obesity and DM. This shows that GDM is a strong risk factor for T2DM and, in rare cases, type 1 diabetes mellitus (T1DM) and maturity-onset diabetes of the young (MODY). This further shows that GDM significantly contributes to the rising incidence and burden of DM worldwide and its prevention may reverse the trend.

Conclusion

Mutations and epigenetic changes in certain genes are strong risk factors for GDM. For affected individuals with such etiologies, medical practitioners should formulate drugs and treatment procedures that target these genes and their pathophysiology.

Heterogeneous impact of type 2 diabetes mellitus-related genetic variants on gestational glycemic traits: review and future research needs

Gestational glucose homeostasis influences mother's metabolic health, pregnancy outcomes, fetal development and offspring growth. To understand the genetic roles in pregnant glucose metabolism and genetic predisposition for gestational diabetes (GDM), we reviewed the recent literature up to Jan, 2018 and evaluated the influence of T2DM-related genetic variants on gestational glycemic traits and glucose tolerance. A total of 140 variants of 89 genes were integrated. Their associations with glycemic traits in and outside pregnancy were compared. The genetic circumstances underlying glucose metabolism exhibit a similarity between pregnant and non-pregnant populations. While, not all of the T2DM-associated genetic variants are related to pregnant glucose tolerance, such as genes involved in fasting insulin/C-peptide regulation. Some genetic variants may have distinct effects on gestational glucose homeostasis. And certain genes may be particularly involved in this process via specific mechanisms, such as HKDC1, MTNR1B, BACE2, genes encoding cell cycle regulators, adipocyte regulators, inflammatory factors and hepatic factors related to gestational glucose sensing and insulin signaling. However, it is currently difficult to evaluate these associations with quantitative synthesis due to inadequate data, different analytical methods, varied measurements for glycemic traits, controversies in diagnosis of GDM, and unknown ethnicity- and/or sex-related influences on pregnant maternal metabolism. In conclusion, different genetic associations with glycemic traits may exist between pregnant and non-pregnant conditions. Comprehensive research on specific genetic regulation in gestation is necessary.

Genetic confirmation of T2DM meta-analysis variants studied in gestational diabetes mellitus in an Indian population

BACKGROUND

Meta-analysis is useful for combining the results of different studies statistically to confirm genuine associations in genetics. Based on earlier reports, we aimed to investigate the association between type 2 diabetes mellitus (T2DM) genetic variants identified in a previous meta-analysis in gestational diabetes mellitus (GDM) in an Indian woman.

MATERIAL AND METHODS

In this study, 137 pregnant women with GDM and 150 pregnant women were selected on the basis of their serum glucose levels. The six single nucleotide polymorphisms (SNPs) of different genes studied had known involvement in pancreatic β-cell function, particular pathways linked to T2DM, and other biological functions. Genomic DNA was isolated from the 287 women for polymerase chain reaction and restriction fragment length polymorphism analyses.

RESULTS

The rs7903146, rs13266634, rs2283228, rs5210 and rs179881 SNPs were found to be positively associated with GDM when calculated for genotype and allele frequencies (p < 0.05), but rs680 (ApaI) variant did not show statistically significant association (p = 0.31). The rs7903146, rs2283228, rs5210 and rs680 variants showed a strong association with oral glucose tolerance test values.

CONCLUSION

The SNPs studied in this GDM had the same role as those identified in a previous T2DM meta-analysis, and showed positive association in the Indian women. Meta-analyses should be implemented to assess the IGF2 gene in GDM subjects.

The Association between SIRT1 Genetic Variation and Type 2 Diabetes Mellitus Is Influenced by Dietary Intake in Elderly Chinese

BACKGROUND

To examine whether polymorphisms of SIRT1 and dietary product intake can be implicated in type 2 diabetes mellitus (T2DM).

METHODS

In this community-based, case-control study, 568 subjects (284 patients and 284 controls) were enrolled in a community located in northern Guangzhou, China. The four polymorphisms of SIRT1 (rs4746720, rs10509291, rs2236319, rs10823116) were examined using TaqMan nuclease technology. The dietary data were collected by an inquiring officer through face-to-face method.

RESULTS

The rs4746720 CC+TT genotype had higher risk compared with CT genotype to develop T2DM [odds ratio (OR) =1.42, 95% confidence interval (CI) = 1.02-1.97]. The subjects with rs4746720 CC+TT genotype and eat sugar food over 30g per day increased the risk of T2DM to 2.22(1.21-4.06) times. The subjects with rs4746720 CC+TT genotype and smoking increased the risk of T2DM to 1.65 (1.10-2.47) times. The unhealthy eating habits such as red meat, salty food, use animal fat yielded higher risks of T2DM, the OR of risk of T2DM was 2.89 (1.38-6.01), 2.73 (1.61-4.64) and 27.91(9.24-84.32) respectively. However, the milk, soy, white meat, vegetables and low-salt diet decreased the risk of T2DM, the OR of risk of T2DM was 0.51 (0.29-0.88), 0.43 (0.26-0.74), 0.51(0.32-0.83), 0.21(0.10-0.44), 0.28(0.12-0.65), 0.35(0.21-0.51) respectively.

CONCLUSION

Variants in SIRT1 with rs4746720 CC+TT genotype increased the risk of T2DM, especially with the unhealthy eating habits.

Geographic diversity in genotype frequencies and meta-analysis of the association between rs1801282 polymorphisms and gestational diabetes mellitus

AIMS

To derive a better understanding of the association between peroxisome proliferator-activated receptor gamma (PPAR-γ) rs1801282 polymorphisms and gestational diabetes mellitus (GDM) in general and in racial and ethnic subgroups and to illustrate geographic distribution of the protective of G allele of rs1801282 in women with and without GDM.

METHODS

ProQuest, PubMed, Medline, Web of Science, and Wanfang Data were systematically searched. Case-control studies on association between rs1801282 polymorphisms and GDM were selected. Comprehensive Meta-Analysis 2.0 statistical software was used to determine the relationship between GDM and rs1801282 polymorphism. Race/ethnicity-based and country-based stratified analysis was conducted.

RESULTS

Sixteen studies involving 3129 cases and 7168 controls were included. Significant associations were observed between rs1801282 polymorphisms and GDM under the dominant, heterozygote, and allele models. The G allele of rs1801282 polymorphism was associated with a reduced risk of GDM in Asian, especially Chinese, populations. Data revealed significant geographic diversity in frequency of the protective G allele in women with and without GDM.

CONCLUSIONS

The rs1801282 polymorphism may not be associated with genetic susceptibility to GDM in whites. The G allele of rs1801282 polymorphism was associated with reduced risk of GDM in Asians, especially Chinese, but not South Koreans.

A Randomized Double-Blinded, Placebo-Controlled Trial Investigating the Effect of Fish Oil Supplementation on Gene Expression Related to Insulin Action, Blood Lipids, and Inflammation in Gestational Diabetes Mellitus-Fish Oil Supplementation and Gestational Diabetes

Gestational diabetes mellitus (GDM) is a common complication of pregnancy, and it is mostly associated with postpartum diabetes, insulin resistance, and dyslipidemia. Fish oil (omega-3) supplementation has been shown to reduce the risk of different chronic diseases such as cardiovascular disease, type 2 diabetes, and cancers, though the evidence of its impact on gestational diabetes is scarce. Our goal in this study was to determine the effect of fish oil administration on gene expression related to insulin action, blood lipids, and inflammation in women with GDM. Participants with GDM (n = 40), aged 18–40 years, were randomized to take either 1000 mg fish oil capsules, containing 180 mg eicosapentaenoic acid and 120 mg docosahexaenoic acid (n = 20), or placebo (n = 20) twice a day for 6 weeks. Gene expression related to insulin, lipids, and inflammation was quantified in peripheral blood mononuclear cells (PBMCs) of GDM women using Reverse Transcription Polymerase Chain Reaction (RT-PCR) method. Results of RT-PCR indicated that omega-3 supplementation upregulated gene expression of peroxisome proliferator-activated receptor gamma (PPAR-γ) (P = 0.04) in PBMCs of patients with GDM, compared with the placebo. In addition, gene expression of the low-density lipoprotein receptor (LDLR) (P < 0.001), interleukin-1 (IL-1) (P = 0.007), and tumor necrosis factor alpha (TNF-α) (P = 0.01) was downregulated in PBMCs of women with GDM, following omega-3 supplementation. No significant effect of omega-3 supplementation was indicated on gene expression of IL-8 in PBMCs of patients with GDM. Overall, fish oil supplementation for 6 weeks in women with GDM significantly improved gene expression of PPAR-γ, IL-1, and TNF-α, but not gene expression of IL-8.

Type 2 diabetes-associated genetic variants of FTO, LEPR, PPARg, and TCF7L2 in gestational diabetes in a Brazilian population

Objective

Gestational diabetes mellitus (GDM) is a metabolic disorder that shares pathophysiologic features with type 2 diabetes mellitus. The aim of this study was to investigate the association of the polymorphisms fat mass and obesity-associated (FTO) rs1421085, leptin receptor (LEPR) rs1137100, rs1137101, peroxisome proliferator-activated receptor gamma (PPARg) rs1801282, and transcription factor 7-like 2 (TCF7L2) rs7901695 with GDM.

Subjects and methods

252 unrelated Euro-Brazilian pregnant women were classified into two groups according to the 2015 criteria of the American and Brazilian Diabetes Association: healthy pregnant women (n = 125) and pregnant women with GDM (n = 127), matched by age. The polymorphisms were genotyped using fluorescent probes (TaqMan®).

Results

All groups were in Hardy-Weinberg equilibrium. The genotype and allele frequencies of the studied polymorphisms did not show significant differences between the groups (P > 0.05). In the healthy and GDM groups, the C allele frequencies (95% CI) of the FTO rs1421085 polymorphism were 36.8% [31-43%] and 35.0% [29-41%]; the G allele frequencies (95% CI) of the LEPR rs1137100 polymorphism were 24.8% [19-30%] and 22.8% [18-28%]; the G allele frequencies (95% CI) of the LEPR rs1137101 polymorphism were 43.6% [37-50%] and 42.9% [37-49%]; the G allele frequencies (95% CI) of the PPARg rs1801282 polymorphism were 7.6% [4-11%] and 8.3% [5-12%]; and the C allele frequencies (95% CI) of the TCF7L2 rs7901695 polymorphism were 33.6% [28-39%] and 39.0% [33-45%], respectively.

Conclusion

The studied polymorphisms were not associated with GDM in a Brazilian population.

KCNQ1 rs2237895 polymorphism is associated with Gestational Diabetes in Pakistani Women

Background and Objective:

Genetic studies on gestational diabetes (GDM) are relatively scarce; moreover, limited data is available for KCNQ1 polymorphism in Pakistani pregnant women. We aimed to determine the frequency of KCNQ1 rs2237895 in GDM and normal pregnant controls and its association with GDM-related phenotypes.

Methods:

A total of 637 pregnant females (429 controls and 208 cases) in their second trimester were classified according to the International Association of the Diabetes and Pregnancy Study criteria in this study. Their blood samples were genotyped for KCNQ1 SNP rs2237895 using PCR-RFLP method and sequencing. Fasting and two hour-post glucose load blood levels, serum HbA1c, insulin, and anthropometric assessment was performed.: Pearson’s Chi Square test, Mann- Whitney U test, and regression analyses were performed. A p-value of <0.05 was considered significant.

Results:

The variant genotyped was in Hardy-Weinberg equilibrium (p>0.05). The rs2237895 showed an association with GDM (OR 2.281; 1.388-3.746: p <0.001) and remained significant after multiple adjustments for age and body mass index (OR 2.068; 1.430-2.997: p=0.005). The C allele showed positive association with insulin level, and HOMA-IR in study subjects.

Conclusions:

This study identifies that KCNQ1 rs2237895 polymorphisms might be associated with risk of GDM in Pakistani population and that it is related to higher glucose levels and insulin resistance. Further large scale studies are required to consolidate on the functional aspect of this polymorphism.

Peroxisome proliferator-activated receptor Pro12Ala polymorphism and the risks of gestational diabetes mellitus: An updated meta-analysis of 12 studies

BACKGROUND

Peroxisome proliferator-activated receptors-λ (PPAR-λ) is a member of nuclear receptor superfamily and acts as a ligand-dependent transcription factor often found in the adrenal gland, the spleen, and adipose tissue. The Pro12Ala polymorphism of PPAR-λ has been associated with the risks of gestational diabetes mellitus (GDM); however, association studies have provided conflicting results. The aim of this Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) compliant meta-analysis is to reach a more up-to-date and accurate estimation of the relationship between Pro12Ala genetic polymorphisms and the risks of GDM.

METHODS

Eligible studies were retrieved by searching PubMed, EMBASE, Web of Science, Ovid, WanFang, and Chinese National Knowledge Databases and selected according to a pre-defined inclusion criterion. The risk of bias was assessed using the Newcastle-Ottawa quality assessment scale. The per-allele odds ratio (OR) of risk allele proline (Pro) was compared between cases and controls in each study to describe the association between the Pro allele and an individual's risk of GDM. The ORs were pooled using both the random-effects model (the DerSimonian and Laird method) and the fixed effects model (the Mantel-Haenszel method) and the 95% confidence interval (95% CI) was calculated using Woolf method.

RESULTS

The final meta-analysis included a total of 11 articles of 12 data sets consisting of 7054 controls and 2980 GDM cases. Our results demonstrate that the Pro allele is not associated with GDM [OR: across multiple populations, 95% CI: 0.98-1.24; P(Z) = 0.01; P(Q) = 0.003]. In the stratified analysis by ethnicity, significantly increased risks were found for the Chinese (OR = 2.36; 95% CI: 1.47-3.78) and Korean (OR = 1.39; 95% CI: 1.00-1.93) populations.

CONCLUSION

These data suggest the potential role of Pro allele in the pathogenesis of GDM in Asian populations. Although the funnel plot of included studies showed assymetry, the results using the "trim and fill" method did not alter the conclusion of this study.

Genetic variants associated with gestational diabetes mellitus: a meta-analysis and subgroup analysis

Previous studies have demonstrated that gestational diabetes mellitus (GDM) and Type 2 diabetes mellitus (T2D) share common genetic polymorphisms. We conducted meta-analysis and subgroup analysis of all available variants and determined the effects of confounding and experimental components on the genetic association of GDM. Any case-controlled or cohort studies with genotype distribution compared GDM cases with controls were included. In total, 28 articles including 8,204 cases and 15,221 controls for 6 polymorphisms were studied. rs10830963(MTNR1B), rs7903146(TCF7L2), and rs1801278(IRS1) were significantly associated with the increased GDM risk. The association of rs4402960(IGF2BP2) and rs1800629(TNF-α) was significant only when the studies with control allele frequency deviation and publication bias were excluded. Further subgroup analysis showed the risk alleles of rs7903146(TCF7L2) and rs1801282(PPARG) were significantly associated with the GDM risk only in Asian, but not in Caucasian population. The OGTT test using 100 g, but not 75 g; and genotype detection by other assays, but not Taqman method, were also significantly associated with increased GDM risk in rs1801278(IRS1) and rs7903146(TCF7L2). Overall GDM was associated with rs10830963(MTNR1B), rs7903146(TCF7L2), and rs1801278(IRS1), but only rs7903146(TCF7L2) and rs1801282(PPARG) were significant in Asian populations. While rs1801278(IRS1) and rs7903146(TCF7L2) were significantly affected by OGTT protocol and genotyping methods.

Prenatal Exposures to Multiple Thyroid Hormone Disruptors: Effects on Glucose and Lipid Metabolism

Background. Thyroid hormones (THs) are essential for normal human fetal development and play a major role in the regulation of glucose and lipid metabolism. Delivery of TH to target tissues is dependent on processes including TH synthesis, transport, and metabolism. Thyroid hormone endocrine disruptors (TH-EDCs) are chemical substances that interfere with these processes, potentially leading to adverse pregnancy outcomes. Objectives. This review focuses on the effects of prenatal exposures to combinations of TH-EDCs on fetal and neonatal glucose and lipid metabolism and also discusses the various mechanisms by which TH-EDCs interfere with other hormonal pathways. Methods. We conducted a comprehensive narrative review on the effects of TH-EDCs with particular emphasis on exposure during pregnancy. Discussion. TH imbalance has been linked to many metabolic processes and the effects of TH imbalance are particularly pronounced in early fetal development due to fetal dependence on maternal TH for proper growth and development. The pervasive presence of EDCs in the environment results in ubiquitous exposure to either single or mixtures of EDCs with deleterious effects on metabolism. Conclusions. Further evaluation of combined effects of TH-EDCs on fetal metabolic endpoints could improve advice provided to expectant mothers.

Insertion and deletion polymorphism in the alpha-2B adrenoceptor gene in pregnant women ripens gestational diabetes mellitus

There are no earlier studies that reported the association of the 12Glu9 polymorphism in the alpha-2B adrenoceptor (ADRA2B) gene with gestational diabetes mellitus (GDM). We examined the potential association between the ADRA2B gene insertion/deletion (I/D) polymorphism in the Saudi population with GDM. Pregnant women with GDM have been reported to exhibit the same susceptibility as that observed in type 2 diabetes mellitus (T2DM). We have selected I/D polymorphism of the ADRA2B gene located in chromosome 2q11.1 that has been extensively related to T2DM and cardiovascular diseases. This case–control study was conducted with 200 GDM and 300 non-GDM pregnant women. Genotyping of I/D polymorphism was performed by conventional PCR method. Biochemical analyses were found to be significantly different between GDM and non-GDM subjects (p < 0.05). Genotype (ID + DD vs II, p = 0.0002) and allele (D vs I, p = 0.0002) frequencies of the 12Glu9 polymorphism were found to be statistically significant. However, a significant difference was found between allele and genotypes of I/D polymorphism of the ADRA2B gene or the clinical characteristics of the subjects. Our results obtained in this study indicate the ADRA2B gene in the Saudi women was associated with the development of GDM.

Correlation between KCNQ1 and KCNJ11 gene polymorphisms and type 2 and post-transplant diabetes mellitus in the Asian Indian population

Type 2 diabetes mellitus (T2DM) and post-transplant diabetes mellitus (PTDM) share a common pathophysiology. However, diabetes mellitus is a complex disease, and T2DM and PTDM have different etiologies. T2DM is a metabolic disorder, characterized by persistent hyperglycemia, whereas PTDM is a condition of abnormal glucose tolerance, with variable onset after organ transplant. The KCNQ1 and KCNJ11 gene encode potassium channels, which mediate insulin secretion from pancreatic β-cells, and KCN gene mutations are correlated with the development of diabetes. However, no studies have been carried out to establish an association between KCNQ1 and KCNJ11 gene polymorphisms and T2DM and PTDM. Therefore, our study was aimed at the identification of the role of KCNQ1 and KCNJ11 gene polymorphisms associated with T2DM and the risk of developing PTDM in the Asian Indian population. We have carried out a case-control study including 250 patients with T2DM, 250 control subjects, 42 patients with PTDM and 98 subjects with non-PTDM. PCR-RFLP analysis was carried out following the isolation of genomic DNA from EDTA-blood samples. The results of the present study reveal that two single nucleotide polymorphisms (rs2283228 and rs5210, of the KCNQ1 and KCNJ11 genes, respectively) are associated with both T2DM and PTDM. The results of our study suggest a role of KCNQ1 and KCNJ11 gene variants in the increased risk of T2DM and PTDM in the Asian Indian population.

The rs2237892 Polymorphism in KCNQ1 Influences Gestational Diabetes Mellitus and Glucose Levels: A Case-Control Study and Meta-Analysis

Objective

Recent genetic studies have shown that potassium voltage-gated channel, KQT-like subfamily, member1 (KCNQ1) gene is related to gestational diabetes mellitus (GDM). However, studies for the rs2237892 polymorphism in KCNQ1 and GDM remain conflicting in Asians. Furthermore, associations of this polymorphism with glucose levels during oral glucose tolerance test (OGTT) have not been described in Chinese pregnant women. The present study aimed to provide evidence for the associations of rs2237892 in KCNQ1 with GDM and glucose levels, and to systematically evaluate the effect of rs2237892 on GDM in Asians.

Methods

A case-control study on 562 women with GDM and 453 controls was conducted in Beijing, China. The association of rs2237892 with risk of GDM was analyzed using logistic regression. The associations with quantitative glucose levels were assessed using linear regression models. A meta-analysis including the present case-control study and four previously published reports in Asians was conducted.

Results

The rs2237892 polymorphism in KCNQ1 was associated with GDM (OR (95%CI) =1.99(1.26-3.15)). Additionally, the polymorphism was associated with levels of 1h and 2h glucose during OGTT. The pre-pregnancy BMI, age and genotypes of KCNQ1 polymorphism were independent risk factors of GDM. Subsequently, we performed a meta-analysis in Asians. In total, C-allele carriers of rs2237892 polymorphism had a 50% higher risk for GDM (OR (95%CI) =1.50(1.15-1.78)).

Conclusion

The study demonstrated for the first time that the KCNQ1 rs2237892 polymorphism was associated with GDM and glucose levels in Chinese women. The study provides systematic evidence for the association between this polymorphism and GDM in Asians.

Angiotensin converting enzyme gene polymorphism studies: A case-control study

Mild gestational hyperglycemia (MGH) is a very common complication of pregnancy that is characterized by intolerance to glucose. The association of angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism to MGH has been previously reported. In this study, we evaluated the association between ACE polymorphism and the risk of MGH in a Saudi population. We conducted a case-control study in a population of 100 MGH patients and 100 control subjects. ACE gene polymorphism was analyzed by the novel approach of tetraprimer amplification refractory mutation system (ARMS)-polymerase chain reaction (PCR). The frequency of ACE polymorphism was not associated with either alleles or genotypes in MGH patients. Glucose concentration was found to be significantly associated with the MGH group. Our study suggests that ACE genotypes were not associated with ACE polymorphism in a Saudi population.

Insulin-like Growth Factor 2 Overexpression Induces β-Cell Dysfunction and Increases Beta-cell Susceptibility to Damage

The human insulin-like growth factor 2 (IGF2) and insulin genes are located within the same genomic region. Although human genomic studies have demonstrated associations between diabetes and the insulin/IGF2 locus or the IGF2 mRNA-binding protein 2 (IGF2BP2), the role of IGF2 in diabetes pathogenesis is not fully understood. We previously described that transgenic mice overexpressing IGF2 specifically in β-cells (Tg-IGF2) develop a pre-diabetic state. Here, we characterized the effects of IGF2 on β-cell functionality. Overexpression of IGF2 led to β-cell dedifferentiation and endoplasmic reticulum stress causing islet dysfunction in vivo. Both adenovirus-mediated overexpression of IGF2 and treatment of adult wild-type islets with recombinant IGF2 in vitro further confirmed the direct implication of IGF2 on β-cell dysfunction. Treatment of Tg-IGF2 mice with subdiabetogenic doses of streptozotocin or crossing these mice with a transgenic model of islet lymphocytic infiltration promoted the development of overt diabetes, suggesting that IGF2 makes islets more susceptible to β-cell damage and immune attack. These results indicate that increased local levels of IGF2 in pancreatic islets may predispose to the onset of diabetes. This study unravels an unprecedented role of IGF2 on β-cells function.

Relationship between the paraoxonase 1 gene glutamine 192 to arginine polymorphism and gestational diabetes mellitus in Saudi women

OBJECTIVES

Gestational diabetes mellitus (GDM) is recognized as an imbalance between insulin resistance and insulin secretion, leading to maternal hyperglycemia. Previous studies in a Saudi population indicated a high frequency of Paraoxonase 1 glutamine 192 to arginine (PON1 Q192R) polymorphism, suggesting this polymorphism as an additional risk factor. The present study was designed to explore the possible association between the PON1 Q192R polymorphism and GDM in a Saudi population.

METHODS

This case-control study was carried out in 500 pregnant women, including 200 GDM cases and 300 non-GDM women. Genotyping for PON1 Q192R (rs662) variants was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

RESULTS

The results of the present study indicates that Q192R polymorphism was significantly associated with GDM in a Saudi population with the minor allele frequency (MAF) (p=0.0007). Q192R genotypes and alleles showed a strong association with GDM (p=0.009 and p=0.0007, respectively).

CONCLUSION

In conclusion, these findings suggest that the PON1 Q192R polymorphism has high MAF in GDM in the studied Saudi population.

Genetic Counseling for Diabetes Mellitus

Most diabetes is polygenic in etiology, with (type 1 diabetes, T1DM) or without (type 2 diabetes, T2DM) an autoimmune basis. Genetic counseling for diabetes generally focuses on providing empiric risk information based on family history and/or the effects of maternal hyperglycemia on pregnancy outcome. An estimated one to five percent of diabetes is monogenic in nature, e.g., maturity onset diabetes of the young (MODY), with molecular testing and etiology-based treatment available. However, recent studies show that most monogenic diabetes is misdiagnosed as T1DM or T2DM. While efforts are underway to increase the rate of diagnosis in the diabetes clinic, genetic counselors and clinical geneticists are in a prime position to identify monogenic cases through targeted questions during a family history combined with working in conjunction with diabetes professionals to diagnose and assure proper treatment and familial risk assessment for individuals with monogenic diabetes.

Investigation of Calpain 10 (rs2975760) gene polymorphism in Asian Indians with Gestational Diabetes Mellitus

Background

Type 2 Diabetes Mellitus (T2DM) and Gestational Diabetes Mellitus (GDM) are part of a heterogeneous and complex metabolic group of disorders that share common pathophysiological circumstances, including β-cell dysfunction and insulin resistance. The protein Calpain 10 (CAPN10) plays a role in glucose metabolism, pancreatic β-cell insulin secretion, and thermogenesis.

Objective

Polymerase Chain Reaction–Restriction Fragment Length Polymorphism (PCR–RFLP) based genotyping of CAPN10 (rs2975760) polymorphism was carried out in T2DM and GDM with suitable controls for each of the pathologies from the same population. Genomic DNA was isolated from 787 participants, including 250 cases of T2DM, 287 pregnant women, of which 137 were identified as having GDM and the remaining 150 were confirmed as non-GDM, and 250 healthy control volunteers, and association analysis was carried out for genotypes and alleles.

Results

In the present study, T2DM was compared with healthy controls and was not found to be associated with the CAPN10 C allele (odds ratio, OR: 1.09; 95% CI = 0.8011–1.484; p = 0.5821). GDM also did not show any association when compared with non-GDM (OR: 1.124; 95% CI = 0.7585–1.667; p = 0.5606) respectively.

Conclusion

Our study suggests that the CAPN10 (rs2975760) polymorphism scrutinized in this study is not associated with T2DM and GDM.

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In this study Calpain 10 (CAPN10) gene was carried out with Type 2 Diabetes Mellitus (T2DM) and Gestational Diabetes Mellitus (GDM). T2DM and GDM are different etiologies of the same complex diseases, frequently coexisting disorders and major components of metabolic syndrome that cause a substantial public health and economic burden worldwide.

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In this study T2DM, GDM are subsequently studied with rs2975760 polymorphism in CAPN10 gene.

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Molecular Analysis were performed by PCR-RFLP analysis.

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A total of 787 samples were included.

Insulin receptor substrate-1 (IRS-1) Gly927Arg: correlation with gestational diabetes mellitus in Saudi women

Pregnant women with gestational diabetes mellitus (GDM) and type 2 diabetes mellitus (T2DM) share a common pathophysiology associated with similar risk factors. Genetic variants used to determine the risk of developing T2DM might also be associated with the prevalence of GDM. The aim of the present study was to scrutinize the relationship between the G972R polymorphism of the insulin receptor substrate-1 (IRS-1) gene with GDM in the Saudi female population. This is a case-control study that monitored 500 Saudi women. Subjects with GDM (n = 200) were compared with non-GDM (n = 300) controls. We opted to evaluate rs1801278 polymorphism in the IRS1 gene, which plays a critical role in the insulin-signaling pathway. Genotyping was performed with the Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) method. The frequency of the rs1801278 polymorphism was significantly higher in women with GDM than in women with non-GDM (for TT + CT versus CC: P = 0.02). Additionally, there was a significant increase in the frequency of the Arg-encoding mutant allele from GDM to non-GDM (for T versus C: P = 0.01). Our results suggest that the rs1801278 polymorphism in the IRS-1 gene is involved in the occurrence of GDM in the Saudi population.