Genetics of Gestational Diabetes Mellitus and Maternal Metabolism

Gestational diabetes mellitus - more than the eye can see - a warning sign for future maternal health with transgenerational impact

Gestational diabetes mellitus (GDM) is regarded by many as maternal maladaptation to physiological insulin resistance during the second half of pregnancy. However, recent evidence indicates that alterations in carbohydrate metabolism can already be detected in early pregnancy. This observation, the increasing prevalence of GDM, and the significant short and long-term implications for the mother and offspring call for reevaluation of the conceptual paradigm of GDM as a syndrome. This review will present evidence for the syndromic nature of GDM and the controversies regarding screening, diagnosis, management, and treatment.

Methylation of the telomerase gene promoter region in umbilical cord blood of patients with gestational diabetes mellitus is associated with decreased telomerase expression levels and shortened telomere length

Objective

This study speculates that gestational diabetes mellitus (GDM) may reduce fetal telomere length (TL),which may be related to modification of methylation in the promoter region of the telomerase (TE) gene promoter region.

Methods

In this study, umbilical cord blood samples from patients with and without GDM (N = 100 each) were analyzed by prospective case-control. The TL, TE expression levels, and methylation levels of TERT and TERC gene promoter regions in two groups were measured. The significance of the methylation level of each CpG locus employed logistic regression analysis of R software, and the analysis of covariance (ANCOVA) was used to control the influence of confounding factors. Correlation analysis was performed by the Spearman.

Results

The TL and TE expression levels of the offspring of GDM patients were decreased despite adjusting for PBMI, PWG, and TG. A total of two CpG islands were screened in the promoter region of the TERT gene and three fragments (TERT_2, TERT_3, and TERT_4) containing a total of 70 CpG sites were designed. Additionally, four CpG sites of the TERT gene in the GDM group (TERT_2_40, TERT_2_47, TERT_3_46, and TERT_3_212) showed increased methylation levels compared with the control group (all P < 0.05). In the promoter region of the TERC gene, one CpG island containing 19 CpG loci was screened and designed, and the methylation levels of the two CpG sites were significantly different in TERC_1_67 (0.65 ± 0.21 versus 0.57 ± 0.30; P = 0.040) and TERC_1_120 (0.68 ± 0.23 versus 0.59 ± 0.27; P = 0.014). The methylation levels of TERC gene fragments of GDM patients were significantly higher than those of the control group (0.69 ± 0.06 versus 0.65 ± 0.08, P = 0.001).

Conclusion

This study revealed that GDM may induce decreased TE expression by increasing the methylation levels of TE genes promoter region, thereby reducing the TL.

Unveiling Gestational Diabetes: An Overview of Pathophysiology and Management

Gestational diabetes mellitus (GDM) is characterized by an inadequate pancreatic β-cell response to pregnancy-induced insulin resistance, resulting in hyperglycemia. The pathophysiology involves reduced incretin hormone secretion and signaling, specifically decreased glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), impairing insulinotropic effects. Pro-inflammatory cytokines, including tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6), impair insulin receptor substrate-1 (IRS-1) phosphorylation, disrupting insulin-mediated glucose uptake. β-cell dysfunction in GDM is associated with decreased pancreatic duodenal homeobox 1 (PDX1) expression, increased endoplasmic reticulum stress markers (CHOP, GRP78), and mitochondrial dysfunction leading to impaired ATP production and reduced glucose-stimulated insulin secretion. Excessive gestational weight gain exacerbates insulin resistance through hyperleptinemia, which downregulates insulin receptor expression via JAK/STAT signaling. Additionally, hypoadiponectinemia decreases AMP-activated protein kinase (AMPK) activation in skeletal muscle, impairing GLUT4 translocation. Placental hormones such as human placental lactogen (hPL) induce lipolysis, increasing circulating free fatty acids which activate protein kinase C, inhibiting insulin signaling. Placental 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) overactivity elevates cortisol levels, which activate glucocorticoid receptors to further reduce insulin sensitivity. GDM diagnostic thresholds (≥92 mg/dL fasting, ≥153 mg/dL post-load) are lower than type 2 diabetes to prevent fetal hyperinsulinemia and macrosomia. Management strategies focus on lifestyle modifications, including dietary carbohydrate restriction and exercise. Pharmacological interventions, such as insulin or metformin, aim to restore AMPK signaling and reduce hepatic glucose output. Emerging therapies, such as glucagon-like peptide-1 receptor (GLP-1R) agonists, show potential in improving glycemic control and reducing inflammation. A mechanistic understanding of GDM pathophysiology is essential for developing targeted therapeutic strategies to prevent both adverse pregnancy outcomes and the progression to overt diabetes in affected women.

Maternal genomic profile, gestational diabetes control, and Mediterranean diet to prevent low birth weight

Low birth weight (LBW) is associated to poor health outcomes. Its causes include maternal lifestyle, obstetric factors, and fetal (epi)genetic abnormalities. This study aims to increase the knowledge regarding the genetic background of LBW by analyzing its association with a set of 110 maternal variants related to gestational diabetes mellitus, in the setting of a nutritional intervention with Mediterranean diet. The analysis follows a multifactorial approach, including maternal genetic information of 1,642 pregnant women, along with their anthropometric and metabolic characteristics. Binary logistic regression models provided 33 discovery variants associated with LBW that underwent a functional enrichment process to obtain a protein/gene interaction network and 126 enriched terms. Overall, our analysis proves that genetic variants form proximity clusters, grouped into subsets statistically associated with underlying biological processes or other maternal characteristics, which, on their part, allow early prevention of the eventual risk of LBW.

Genetic disorders in maternal medicine

The role of genetic testing within maternal medicine is expanding. Advancing technology and the increasing availability of genetic testing have seen more patients receiving a genetic diagnosis than ever before. Improved healthcare and understanding of these rare diseases means that many patients are living well into their reproductive years and starting families. Individual diseases are considered by their patterns of inheritance i.e. autosomal recessive, autosomal dominant and chromosomal diseases. This chapter specifically addresses the following examples and outlines an approach to pre-conceptual and pregnancy management; autosomal recessive (cystic fibrosis, phenylketonuria), autosomal dominant (osteogenesis imperfecta, vascular Ehlers-Danlos syndrome) and chromosomal (Turner syndrome). For many rare and ultrarare genetic diseases, there may be no clear guidelines or consensus on the correct management in pregnancy. This chapter seeks to provide a framework for the clinician to use to address the unique needs and risk profile of these patients in pregnancy and pre-conceptually and plan accordingly. The role of pharmacogenetics in maternal medicine, the future of education in genetics for patients and clinicians and the important role of genetic counselling are all considered in this chapter. This overview highlights the important role of genetics in maternal medicine and how this can inform management and planning for the safe care of mother and baby.

Genetic variants related to insulin metabolism are associated with gestational diabetes mellitus

The current study sought to investigate the associations of common genetic risk variants with gestational diabetes mellitus (GDM) risk in the north Indian population and to evaluate their utility in identifying GDM cases. A case-control study, including 300 pregnant women, was included, and clinical and pathological information was collected. The amplification-refractory mutation system (ARMS) was used for genotyping four single nucleotide polymorphisms (SNPs), namely FTO (rs9939609), PPARG2 (rs1801282), SLC30A8 (rs13266634), and TCF7L2 (rs12255372). The odds ratio and confidence interval were determined for each SNP in different genetic models. Further, attributable risk, population penetrance, and relative risk were also calculated. The risk allele A of FTO (rs9939609) poses a two times higher risk of GDM (p = 0.02, OR = 2.5). The CG and GG genotypes of PPARG2 (rs1801282) have half a lower risk of GDM. In SLC30A8 (rs13266634), the recessive model analysis showed a two times higher risk of having GDM, while the recessive model (TT vs. GG + GT) analysis in TCF7L2 (rs12255372) indicates a lower risk of GDM. Finally, the relative risk, population penetrance, and attributable risk for risk allele in all four variants was higher in GDM mothers. All four polymorphisms were found to be significantly associated with BMI, HbA1c, and insulin. Our study first time confirmed a significant association with GDM for four variants, FTO, PPARG2, SLC30A8, and TCF7L2, in the North Indian population.

Genetic Predisposition to Prediabetes in the Kazakh Population

The aim of this study was to conduct a comparative analysis of the population frequencies of the minor allele of polymorphic variants in the genes TCF7L2 (rs7903146) and PPARG (rs1801282), based on the genome-wide association studies analysis data associated with the risk of developing prediabetes, in an ethnically homogeneous Kazakh population compared to previously studied populations worldwide. This study utilized a genomic database consisting of 1800 ethnically Kazakh individuals who were considered in healthy condition. Whole-genome genotyping was performed using Illumina OmniChip 2.5-8 arrays, which interrogated approximately 2.5 million single nucleotide polymorphisms. The distribution of genotypes for the TCF7L2 (rs7903146) and PPARG (rs1801282) polymorphisms in the Kazakh sample was found to be in Hardy-Weinberg equilibrium (p > 0.05). The minor G allele of the "Asian" protective polymorphism rs1801282 in the PPARG gene was observed at a frequency of 13.8% in the Kazakh population. This suggests a potentially more significant protective effect of this polymorphism in reducing the risk of prediabetes among Kazakhs. The frequency of the unfavorable T allele of the insulin secretion-disrupting gene TCF7L2 (rs7903146) in Kazakhs was 15.2%. Studying the associations of genetic markers for prediabetes enables the timely identification of "high-risk groups" and facilitates the implementation of effective preventive measures. Further results from replicative genomic research will help identify significant polymorphic variants of genes underlying the alteration of prediabetes status.

Current status and future of genomics in fetal and maternal medicine: A scientific review commissioned by European Board and College of Obstetrics and Gynaecology (EBCOG)

This EBCOG guidance reviews the current and future status of genomics within fetal and maternal medicine. This document addresses the clinical uses of genetic testing in both screening and diagnostic testing prenatally. The role of genomics within fetal and maternal medicine is described. The research and future implications of genetic testing as well as the educational, ethical and economic implications of genomics are discussed.

A Simplified Screening Model to Predict the Risk of Gestational Diabetes Mellitus in Caucasian and Latin American Pregnant Women

The pathophysiology of gestational diabetes mellitus (GDM) comprises clinical and genetic factors. In fact, GDM is associated with several single nucleotide polymorphisms (SNPs). This study aimed to build a prediction model of GDM combining clinical and genetic risk factors. A total of 1588 pregnant women from the San Carlos Cohort participated in the present study, including 1069 (67.3%) Caucasian (CAU) and 519 (32.7%) Latin American (LAT) individuals, and 255 (16.1%) had GDM. The incidence of GDM was similar in both groups (16.1% CAU and 16.0% LAT). Genotyping was performed via IPLEX Mass ARRAY PCR, selecting 110 SNPs based on literature references. SNPs showing the strongest likelihood of developing GDM were rs10830963, rs7651090, and rs1371614 in CAU and rs1387153 and rs9368222 in LAT. Clinical variables, including age, pre-pregnancy body mass index, and fasting plasma glucose (FPG) at 12 gestational weeks, predicted the risk of GDM (AUC 0.648, 95% CI 0.601-0.695 in CAU; AUC 0.688, 95% CI 0.628-9.748 in LAT), and adding SNPs modestly improved prediction (AUC 0.722, 95%CI 0.680-0.764 in CAU; AUC 0.769, 95% CI 0.711-0.826 in LAT). In conclusion, adding genetic variants enhanced the prediction model of GDM risk in CAU and LAT pregnant women.

The relationship between polymorphism of IGF2BP2 gene rs4402960 and risk of pan-cancer: a meta-analysis and a bioinformatics analysis

OBJECTIVE

To conduct a meta-analysis and a bioinformatics analysis to assess the relationship between IGF2BP2 gene polymorphism and pan-cancer risk.

METHODS

PubMed, EMBASE, and Web of Science were conducted to literature searches. The heterogeneity test was used in five genetic models. Odds ratios (OR), 95% confidence intervals (CI), and p-values were used to evaluate the combined effects of various genetic models. Subgroup analysis and Meta-regression analysis were used to analyze the characteristics of heterogeneity. Sensitivity analysis and publication bias were also performed. Transcriptomic information on IGF2BP2 was downloaded and analyzed from the TCGA and GTEx databases. GEPIA (http://gepia.cancer-pku.cn/) was performed to analyze the relationship between IGF2BP2 expression and cancer tissue.

RESULTS

This meta-analysis contained 7 case-control studies, with 5,908 cases and 7,890 controls. There were significant differences in the heterozygous genetic model of IGF2BP2 gene rs4402960 polymorphism (OR = 1.080, 95% CI = 1.003-1.163, p = 0.041). In subgroup analysis based on ethnicity, There was a statistical significant association in Chinese (heterozygous: OR = 1.110, 95% CI = 1.010-1.220, p = 0.030). Bioinformatics analysis found that IGF2BP2 was over-expressed in pan-cancer (p < 0.01). In addition, the Kaplan-Meier estimate showed that there is statistical significance of OS between the low and high IGF2BP2 TPM groups in Lung adenocarcinoma (p <0.001).

CONCLUSIONS

To sum up, IGF2BP2 gene polymorphism may be related to cancer risk. IGF2BP2 has diagnostic value in the diagnosis and treatment of pan-cancer.

Influence of gestational diabetes mellitus on subclinical myocardial dysfunction during pregnancy: A systematic review and meta-analysis

OBJECTIVE

The correlation between gestational diabetes mellitus (GDM) and subclinical myocardial dysfunction has been poorly investigated. Accordingly, we performed a meta-analysis to examine the influence of GDM on left ventricular (LV) global longitudinal strain (GLS), assessed by speckle tracking echocardiography (STE), during pregnancy.

STUDY DESIGN

All echocardiographic studies assessing conventional echoDoppler parameters and LV-GLS in GDM women vs. healthy controls, selected from PubMed and EMBASE databases, were included. The risk of bias was assessed by using the National Institutes of Health (NIH) Quality Assessment of Case-Control Studies. The subtotal and overall standardized mean differences (SMDs) of LV-GLS were calculated using the random-effect model.

RESULTS

The full-texts of 10 studies with 1147 women with GDM and 7706 pregnant women without diabetes were analyzed. GDM women enrolled in the included studies were diagnosed with a small reduction in LV-GLS in comparison to controls (average value -19.4 ± 2.5 vs -21.8 ± 2.5 %, P < 0.001) and to the accepted reference values (more negative than -20 %). Substantial heterogeneity was detected for the included studies, with an overall statistic value I2 of 94.4 % (P < 0.001). Large SMDs were obtained for the included studies, with an overall SMD of -0.97 (95 %CI -1.32, -0.63, P < 0.001). Egger's test for a regression intercept gave a P-value of 0.99, indicating no publication bias. On meta-regression analysis, all moderators and/or potential confounders (age at pregnancy, BMI, systolic blood pressure and ethnicity) were not significantly associated with effect modification (all P < 0.05).

CONCLUSIONS

GDM is independently associated with subclinical myocardial dysfunction in pregnancy. STE analysis allows to identify, among GDM women, those who might benefit of targeted non-pharmacological and/or pharmacological interventions, aimed at reducing the risk of developing type 2 diabetes and cardiovascular complications later in life.

Beta-cell compensation and gestational diabetes

Gestational diabetes mellitus (GDM) is characterized by glucose intolerance in pregnant women without a previous diagnosis of diabetes. While the etiology of GDM remains elusive, the close association of GDM with increased maternal adiposity and advanced gestational age implicates insulin resistance as a culpable factor for the pathogenesis of GDM. Pregnancy is accompanied by the physiological induction of insulin resistance in the mother secondary to maternal weight gain. This effect serves to spare blood glucose for the fetus. To overcome insulin resistance, maternal β-cells are conditioned to release more insulin into the blood. Such an adaptive response, termed β-cell compensation, is essential for maintaining normal maternal metabolism. β-cell compensation culminates in the expansion of β-cell mass and augmentation of β-cell function, accounting for increased insulin synthesis and secretion. As a result, a vast majority of mothers are protected from developing GDM during pregnancy. In at-risk pregnant women, β-cells fail to compensate for maternal insulin resistance, contributing to insulin insufficiency and GDM. However, gestational β-cell compensation ensues in early pregnancy, prior to the establishment of insulin resistance in late pregnancy. How β-cells compensate for pregnancy and what causes β-cell failure in GDM are subjects of investigation. In this mini-review, we will provide clinical and preclinical evidence that β-cell compensation is pivotal for overriding maternal insulin resistance to protect against GDM. We will highlight key molecules whose functions are critical for integrating gestational hormones to β-cell compensation for pregnancy. We will provide mechanistic insights into β-cell decompensation in the etiology of GDM.

Development and validation of a multivariable genotype-informed gestational diabetes prediction algorithm for clinical use in the Mexican population: insights into susceptibility mechanisms

INTRODUCTION

Gestational diabetes mellitus (GDM) is underdiagnosed in Mexico. Early GDM risk stratification through prediction modeling is expected to improve preventative care. We developed a GDM risk assessment model that integrates both genetic and clinical variables.

RESEARCH DESIGN AND METHODS

Data from pregnant Mexican women enrolled in the 'Cuido mi Embarazo' (CME) cohort were used for development (107 cases, 469 controls) and data from the 'Mónica Pretelini Sáenz' Maternal Perinatal Hospital (HMPMPS) cohort were used for external validation (32 cases, 199 controls). A 2-hour oral glucose tolerance test (OGTT) with 75 g glucose performed at 24-28 gestational weeks was used to diagnose GDM. A total of 114 single-nucleotide polymorphisms (SNPs) with reported predictive power were selected for evaluation. Blood samples collected during the OGTT were used for SNP analysis. The CME cohort was randomly divided into training (70% of the cohort) and testing datasets (30% of the cohort). The training dataset was divided into 10 groups, 9 to build the predictive model and 1 for validation. The model was further validated using the testing dataset and the HMPMPS cohort.

RESULTS

Nineteen attributes (14 SNPs and 5 clinical variables) were significantly associated with the outcome; 11 SNPs and 4 clinical variables were included in the GDM prediction regression model and applied to the training dataset. The algorithm was highly predictive, with an area under the curve (AUC) of 0.7507, 79% sensitivity, and 71% specificity and adequately powered to discriminate between cases and controls. On further validation, the training dataset and HMPMPS cohort had AUCs of 0.8256 and 0.8001, respectively.

CONCLUSIONS

We developed a predictive model using both genetic and clinical factors to identify Mexican women at risk of developing GDM. These findings may contribute to a greater understanding of metabolic functions that underlie elevated GDM risk and support personalized patient recommendations.

Genetics and Epigenetics: Implications for the Life Course of Gestational Diabetes

Gestational diabetes (GDM) is one of the most common complications of pregnancy, affecting as many as one in six pregnancies. It is associated with both short- and long-term adverse outcomes for the mother and fetus and has important implications for the life course of affected women. Advances in genetics and epigenetics have not only provided new insight into the pathophysiology of GDM but have also provided new approaches to identify women at high risk for progression to postpartum cardiometabolic disease. GDM and type 2 diabetes share similarities in their pathophysiology, suggesting that they also share similarities in their genetic architecture. Candidate gene and genome-wide association studies have identified susceptibility genes that are shared between GDM and type 2 diabetes. Despite these similarities, a much greater effect size for MTNR1B in GDM compared to type 2 diabetes and association of HKDC1, which encodes a hexokinase, with GDM but not type 2 diabetes suggest some differences in the genetic architecture of GDM. Genetic risk scores have shown some efficacy in identifying women with a history of GDM who will progress to type 2 diabetes. The association of epigenetic changes, including DNA methylation and circulating microRNAs, with GDM has also been examined. Targeted and epigenome-wide approaches have been used to identify DNA methylation in circulating blood cells collected during early, mid-, and late pregnancy that is associated with GDM. DNA methylation in early pregnancy had some ability to identify women who progressed to GDM, while DNA methylation in blood collected at 26-30 weeks gestation improved upon the ability of clinical factors alone to identify women at risk for progression to abnormal glucose tolerance post-partum. Finally, circulating microRNAs and long non-coding RNAs that are present in early or mid-pregnancy and associated with GDM have been identified. MicroRNAs have also proven efficacious in predicting both the development of GDM as well as its long-term cardiometabolic complications. Studies performed to date have demonstrated the potential for genetic and epigenetic technologies to impact clinical care, although much remains to be done.

Mouse Models of Gestational Diabetes Mellitus and Its Subtypes: Recent Insights and Pitfalls

Gestational diabetes mellitus (GDM) is currently the most common complication of pregnancy and is defined as a glucose intolerance disorder with recognition during pregnancy. GDM is considered a uniform group of patients in conventional guidelines. In recent years, evidence of the disease's heterogeneity has led to a growing understanding of the value of dividing patients into different subpopulations. Furthermore, in view of the increasing incidence of hyperglycemia outside pregnancy, it is likely that many cases diagnosed as GDM are in fact patients with undiagnosed pre-pregnancy impaired glucose tolerance (IGT). Experimental models contribute significantly to the understanding of the pathogenesis of GDM and numerous animal models have been described in the literature. The aim of this review is to provide an overview of the existing mouse models of GDM, in particular those that have been obtained by genetic manipulation. However, these commonly used models have certain limitations in the study of the pathogenesis of GDM and cannot fully describe the heterogeneous spectrum of this polygenic disease. The polygenic New Zealand obese (NZO) mouse is introduced as a recently emerged model of a subpopulation of GDM. Although this strain lacks conventional GDM, it exhibits prediabetes and an IGT both preconceptionally and during gestation. In addition, it should be emphasized that the choice of an appropriate control strain is of great importance in metabolic studies. The commonly used control strain C57BL/6N, which exhibits IGT during gestation, is discussed in this review as a potential model of GDM.

Association of CDKAL1 gene polymorphism (rs10946398) with gestational diabetes mellitus in Pakistani population

BACKGROUND

CDK5 regulatory subunit associated protein 1 like 1 (CDKAL1) encodes a tRNA modifying enzyme involved in the proper protein translation and regulation of insulin production encoded by the CDKL gene. Sequence variations in the CDKAL1 gene lead to the misreading of the Lys codon in proinsulin, resulting in decreased glucose-stimulated proinsulin production. Various polymorphic sequence variants of the CDKAL1 gene such as rs7754840, rs7756992, rs9465871, and rs10946398 are reported to be associated with type 2 diabetes mellitus and gestational diabetes mellitus (GDM) incidence. One of these single nucleotide polymorphisms i.e., rs10946398 has been reported to impact the risk of GDM and its outcomes in pregnant women of different ethnicities i.e., Egypt, Chinese, Korean, Indian, Arab, and Malaysian. Numerous findings have shown that rs10946398 overturns the regulation of CDKAL1 expression, resulting in decreased insulin production and elevated risk of GDM. However, there is no data regarding rs10946398 genotype association with GDM incidence in our population.

METHODOLOGY

In this study, 47 GDM patients and 40 age-matched controls were genotyped for rs10946398 CDKAL1 variant using Tetra primer Amplification Refractory Mutation System Polymerase Chain Reaction (Tetra ARMS-PCR).

RESULTS

Analysis of the results showed the significant association of the C allele of CDKAL1 SNP rs10946398 (χ² = 0.02 p = 0.001) with the risk of GDM development. Conclusively, the results support the role of SNP i.e., rs10946398 of CDKAL1 gene in GDM development in Pakistani female patients. However, future large-scale studies are needed to functionally authenticate the role of variant genotypes in the disease pathogenesis and progression.

Genetic predisposition to gestational diabetes mellitus in the Kazakh population

BACKGROUND AND AIMS

The purpose of the study was to conduct a comparative analysis of population frequencies of alleles and genotypes of polymorphic variants of genes for impaired insulin synthesis and associated with insulin signal transduction.

METHODS

This investigation uses a genomic database of 1800 conditionally healthy individuals of Kazakh ethnicity, who underwent full genome genotyping using OmniChip 2.5-8 Illumina chips of ∼2.5 million Single Nucleotide Polymorphism at deCODE Iceland Genomic Centre.

RESULTS

The highest frequency of carriage of minor A allele - 17.6% rs4607517 polymorphism of Glucokinase gene, unfavorable genotypes A/G - 29.5% and A/A - 3.0% in comparison with European and Asian populations, indicates a contribution of hereditary family forms of Maturity-onset diabetes of the young type 2 to gestational diabetes mellitus in Kazakh population.

CONCLUSIONS

The study of the associations of genetic markers of gestational diabetes mellitus will allow timely identification of high-risk groups before and at an early stage of pregnancy, carrying out the necessary effective preventive measures and, in the case of gestational diabetes mellitus development, optimizing the correction of carbohydrate metabolism disorders and predicting outcomes for the mother and the fetus.

Genetic variants for prediction of gestational diabetes mellitus and modulation of susceptibility by a nutritional intervention based on a Mediterranean diet

Hypothesis

Gestational diabetes mellitus (GDM) entails a complex underlying pathogenesis, with a specific genetic background and the effect of environmental factors. This study examines the link between a set of single nucleotide polymorphisms (SNPs) associated with diabetes and the development of GDM in pregnant women with different ethnicities, and evaluates its potential modulation with a clinical intervention based on a Mediterranean diet.

Methods

2418 women from our hospital-based cohort of pregnant women screened for GDM from January 2015 to November 2017 (the San Carlos Cohort, randomized controlled trial for the prevention of GDM ISRCTN84389045 and real-world study ISRCTN13389832) were assessed for evaluation. Diagnosis of GDM was made according to the International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria. Genotyping was performed by IPLEX MassARRAY PCR using the Agena platform (Agena Bioscience, SanDiego, CA). 110 SNPs were selected for analysis based on selected literature references. Statistical analyses regarding patients' characteristics were performed in SPSS (Chicago, IL, USA) version 24.0. Genetic association tests were performed using PLINK v.1.9 and 2.0 software. Bioinformatics analysis, with mapping of SNPs was performed using STRING, version 11.5.

Results

Quality controls retrieved a total 98 SNPs and 1573 samples, 272 (17.3%) with GDM and 1301 (82.7%) without GDM. 1104 (70.2%) were Caucasian (CAU) and 469 (29.8%) Hispanic (HIS). 415 (26.4%) were from the control group (CG), 418 (26.6%) from the nutritional intervention group (IG) and 740 (47.0%) from the real-world group (RW). 40 SNPs (40.8%) presented some kind of significant association with GDM in at least one of the genetic tests considered. The nutritional intervention presented a significant association with GDM, regardless of the variant considered. In CAU, variants rs4402960, rs7651090, IGF2BP2; rs1387153, rs10830963, MTNR1B; rs17676067, GLP2R; rs1371614, DPYSL5; rs5215, KCNJ1; and rs2293941, PDX1 were significantly associated with an increased risk of GDM, whilst rs780094, GCKR; rs7607980, COBLL1; rs3746750, SLC17A9; rs6048205, FOXA2; rs7041847, rs7034200, rs10814916, GLIS3; rs3783347, WARS; and rs1805087, MTR, were significantly associated with a decreased risk of GDM, In HIS, variants significantly associated with increased risk of GDM were rs9368222, CDKAL1; rs2302593, GIPR; rs10885122, ADRA2A; rs1387153, MTNR1B; rs737288, BACE2; rs1371614, DPYSL5; and rs2293941, PDX1, whilst rs340874, PROX1; rs2943634, IRS1; rs7041847, GLIS3; rs780094, GCKR; rs563694, G6PC2; and rs11605924, CRY2 were significantly associated with decreased risk for GDM.

Conclusions

We identify a core set of SNPs in their association with diabetes and GDM in a large cohort of patients from two main ethnicities from a single center. Identification of these genetic variants, even in the setting of a nutritional intervention, deems useful to design preventive and therapeutic strategies.

Gestational Diabetes Mellitus—Recent Literature Review

Gestational diabetes mellitus (GDM), which is defined as a state of hyperglycemia that is first recognized during pregnancy, is currently the most common medical complication in pregnancy. GDM affects approximately 15% of pregnancies worldwide, accounting for approximately 18 million births annually. Mothers with GDM are at risk of developing gestational hypertension, pre-eclampsia and termination of pregnancy via Caesarean section. In addition, GDM increases the risk of complications, including cardiovascular disease, obesity and impaired carbohydrate metabolism, leading to the development of type 2 diabetes (T2DM) in both the mother and infant. The increase in the incidence of GDM also leads to a significant economic burden and deserves greater attention and awareness. A deeper understanding of the risk factors and pathogenesis becomes a necessity, with particular emphasis on the influence of SARS-CoV-2 and diagnostics, as well as an effective treatment, which may reduce perinatal and metabolic complications. The primary treatments for GDM are diet and increased exercise. Insulin, glibenclamide and metformin can be used to intensify the treatment. This paper provides an overview of the latest reports on the epidemiology, pathogenesis, diagnosis and treatment of GDM based on the literature.

Plasminogen activator inhibitor 1 and gestational diabetes: the causal relationship

Plasminogen activator inhibitor 1 (PAI-1) also known as serpin E1 or endothelial plasminogen activator inhibitor, is produced from endothelial cells and adipose tissue. PAI-1 inhibits tissue plasminogen activator (tPA) and urokinase (uPA) preventing activation of plasminogen and fibrinolysis. Gestational diabetes mellitus (GDM) is defined as glucose intolerance and hyperglycemia during pregnancy. The underlying mechanism of GDM is due to the reduction of insulin secretion or the development of insulin resistance (IR). Normal PAI-1 is a crucial mediator for maintaining pregnancy, though aberrantly high PAI-1 promotes inflammation and thrombosis with increased risk of pregnancy loss. Increasing PAI-1 level had been shown to be an early feature of cardio-metabolic derangement in women with GDM. As well, GDM is regarded as an independent predictor for increasing PAI-1 levels compared to normal pregnancy. Taken together, GDM seems to be the causal factor in the increase of PAI-1 via induction of IR, hyperglycemia and hypertriglyceridemia. In conclusion, GDM triggers expression and release of PAI-1 which linked with GDM severity due to exaggerated pro-inflammatory and inflammatory cytokines with the development of IR. High PAI-1 levels in GDM may induce hypofibrinolysis and thrombotic complications.

Risk of large for gestational age births at early, full and late term in relation to pre-pregnancy body mass index: Mediation by gestational diabetes status

BACKGROUND

Maternal pre-pregnancy body mass index (BMI) is strongly associated with infant birthweight and the risk differs in pregnancies complicated by gestational diabetes (GDM).

OBJECTIVES

To examine the risk of large for gestational age (LGA) (≥97th percentile) singleton births at early term, full term and late term in relation to maternal pre-pregnancy BMI status mediated through GDM.

METHODS

We analysed data from the 2018 U.S. National Vital Statistics Natality File restricted to singleton term births (N = 3,229,783). In counterfactual models for causal inference, we estimated the total effect (TE), natural direct effect (NDE) and natural indirect effect (NIE) for the association of pre-pregnancy BMI with subcategories of LGA births at early, full and late term mediated through GDM, using log-binomial regression and adjusting for race/ethnicity, age, education, parity and infant sex. Proportion mediated was calculated on the risk difference scale and potential unmeasured confounders were assessed using the E-value.

RESULTS

Overall, 6.4% of women had GDM, and there were 3.6% LGA singleton term births. The highest prevalence of GDM was among pre-gestational overweight/obesity that also had the highest rates of LGA births at term. The TE estimates for the risk of LGA births were the strongest across women with higher pre-pregnancy BMI compared to women with normal pre-pregnancy BMI. The NDE estimates were higher than the NIE estimates for overweight/obese BMI status. The proportion mediated, which answers the causal question to what extent the total effect of the association between pre-pregnancy BMI and LGA births is accounted for through GDM, was the highest (up to 16%) for early term births.

CONCLUSIONS

Term singleton births make up the largest proportion in a cohort of newborns. While the percentage mediated through GDM was relatively small, health risks arising from pre-pregnancy overweight, and obesity can be substantial to both mothers and their offspring.

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.

Pathophysiological Role of Genetic Factors Associated With Gestational Diabetes Mellitus

Gestational Diabetes Mellitus (GDM) is a highly prevalent maternal pathology characterized by maternal glucose intolerance during pregnancy that is, associated with severe complications for both mother and offspring. Several risk factors have been related to GDM; one of the most important among them is genetic predisposition. Numerous single nucleotide polymorphisms (SNPs) in genes that act at different levels on various tissues, could cause changes in the expression levels and activity of proteins, which result in glucose and insulin metabolism dysfunction. In this review, we describe various SNPs; which according to literature, increase the risk of developing GDM. These SNPs include: (1) those associated with transcription factors that regulate insulin production and excretion, such as rs7903146 (TCF7L2) and rs5015480 (HHEX); (2) others that cause a decrease in protective hormones against insulin resistance such as rs2241766 (ADIPOQ) and rs6257 (SHBG); (3) SNPs that cause modifications in membrane proteins, generating dysfunction in insulin signaling or cell transport in the case of rs5443 (GNB3) and rs2237892 (KCNQ1); (4) those associated with enzymes such as rs225014 (DIO2) and rs9939609 (FTO) which cause an impaired metabolism, resulting in an insulin resistance state; and (5) other polymorphisms, those are associated with growth factors such as rs2146323 (VEGFA) and rs755622 (MIF) which could cause changes in the expression levels of these proteins, producing endothelial dysfunction and an increase of pro-inflammatory cytokines, characteristic on GDM. While the pathophysiological mechanism is unclear, this review describes various potential effects of these polymorphisms on the predisposition to develop GDM.

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.

The impact of short-term hyperglycemia and obesity on biventricular and biatrial myocardial function assessed by speckle tracking echocardiography in a population of women with gestational diabetes mellitus

BACKGROUND AND AIMS

To compare biventricular and biatrial myocardial strain indices assessed by two-dimensional speckle tracking echocardiography (2D-STE) in women with gestational diabetes mellitus (GDM) and those with uncomplicated pregnancy at the third trimester of pregnancy and in post-partum.

METHODS AND RESULTS

30 consecutive GDM women and 30 age-, ethnicity- and gestational week-matched controls without any comorbidity were examined in this prospective case-control study. All women underwent obstetric visit, blood tests and transthoracic echocardiography (TTE) implemented with 2D-STE analysis of all cardiac chambers at 36-38 weeks' gestation. TTE and 2D-STE were repeated at 6-10 weeks after delivery. At 36-38 weeks' gestation, GDM women, compared to controls, had significantly higher body mass index (BMI), blood pressure values and inflammatory markers. TTE showed increased left ventricular (LV) mass and impaired LV diastolic function in GDM women, whereas there was no significant difference between the groups in ejection fraction. 2D-STE revealed that biventricular global longitudinal strain (GLS) and biatrial reservoir strain indices were significantly lower in GDM women than controls. Third trimester BMI was inversely correlated with LV-GLS (r = -0.86) and was independently associated with reduced LV-GLS (less negative than -20%) in GDM women in post-partum (OR 1.81, 95%CI 1.14-2.89). A BMI value ≥ 30 kg/m² had 100% sensitivity and 99.5% specificity for identifying GDM women with impaired LV-GLS in post-partum (AUC = 0.97).

CONCLUSION

Women with GDM, compared to women with uncomplicated pregnancy, have significantly lower biventricular and biatrial myocardial deformation indices. These abnormalities may be persistent in post-partum in GDM women with obesity.

Application of Metabolomics in Various Types of Diabetes

Metabolomics is the analysis of numerous small molecules known as metabolites. Over the past few years, with the continuous development in metabolomics, it has been widely used in the detection, diagnosis, and treatment of diabetes and has demonstrated great benefits. At the same time, studies on diabetes and its complications have discovered the metabolic markers that are characteristic of diabetes. However, the pathogenesis of diabetes has yet to be clarified, as well as no complete cure. The mechanism of diabetes has not been completely elucidated, and its eradication treatment is not available. Thus, prevention of the onset of the disease and its treatment have become very important. In this review, we focused on the recent progress in the use of metabolites in diabetes and their complications, as well as understanding the impact of diabetes metabolites.

Genetic risk factors associated with gestational diabetes in a multi-ethnic population

AIMS

Genome-wide association studies have shown an increased risk of type-2-diabetes (T2DM) in patients who carry single nucleotide polymorphisms in several genes. We investigated whether the same gene loci confer a risk for gestational diabetes mellitus (GDM) in women from Hawaii, and in particular, Pacific Islander and Filipino populations.

METHODS

Blood was collected from 291 women with GDM and 734 matched non-diabetic controls (Pacific Islanders: 71 GDM, 197 non-diabetic controls; Filipinos: 162 GDM, 395 controls; Japanese: 58 GDM, 142 controls). Maternal DNA was used to genotype and show allele frequencies of 25 different SNPs mapped to 18 different loci.

RESULTS

After adjusting for age, BMI, parity and gravidity by multivariable logistic regression, several SNPs showed significant associations with GDM and were ethnicity specific. In particular, SNPs rs1113132 (EXT2), rs1111875 (HHEX), rs2237892 (KCNQ1), rs2237895 (KCNQ1), rs10830963 (MTNR1B) and rs13266634 (SLC30A8) showed significant associations with GDM in Filipinos. For Japanese, SNPs rs4402960 (IGFBP2) and rs2237892 (KCNQ1) were significantly associated with GDM. For Pacific Islanders, SNPs rs10830963 (MTNR1B) and rs13266634 (SLC30A8) showed significant associations with GDM. Individually, none of the SNPs showed a consistent association with GDM across all three investigated ethnicities.

CONCLUSION

Several SNPs associated with T2DM are found to confer increased risk for GDM in a multiethnic cohort in Hawaii.

Novel association between a transient receptor potential cation channel subfamily M member 5 expression quantitative trait locus rs35197079 and decreased susceptibility of gestational diabetes mellitus in a Chinese population

AIMS/INTRODUCTION

Emerging evidence suggests that expression quantitative trait loci (eQTLs) are more likely to associate with complex diseases. Transient receptor potential cation channel subfamily M member 5 (TRPM5) is a ubiquitously expressed voltage-gated cation channel that acts indispensably to trigger insulin secretion in pancreatic β-cells. The present study evaluated the association between TRPM5 eQTL single-nucleotide polymorphisms and the risk of gestational diabetes mellitus (GDM) in a Chinese population.

MATERIALS AND METHODS

A total of 380 unrelated Chinese pregnant women including 241 GDM patients and 139 controls were included in this study. The eQTL single-nucleotide polymorphisms of TRPM5 were obtained from the GTEx eQTL Browser, and were subsequently genotyped using the Agena MassARRAY iPLEX platform.

RESULTS

Logistic regression analysis and linear regression analysis showed that rs35197079 and rs74848824 were significantly associated with reduced GDM risk and lower fasting plasma glucose levels after adjusting confounder factors in dominant genetic models. Stratification analysis based on pre-pregnancy body mass index validated a strong association between rs35197079 and GDM susceptibility in underweight and normal weight individuals. Luciferase and electrophoretic mobility shift assays carried out in rat pancreatic β-cells showed that rs35197079 was functional.

CONCLUSIONS

The TRPM5 eQTL single-nucleotide polymorphism rs35197079 was associated with decreased GDM susceptibility in a Chinese population, especially in underweight and normal weight pregnant women, and it was functional in modulating gene transcription.

Association between functional genetic variants in retinoid X receptor-α/γ and the risk of gestational diabetes mellitus in a southern Chinese population

To clarify the effect of retinoid X receptor-α/γ (RXR-α/γ) genes functional genetic variants (RXR-α rs4842194 G>A, RXR-γ rs100537 A>G and rs2134095 T>C) on the risk of gestational diabetes mellitus (GDM), a case–control study with 573 GDM patients and 740 pregnant women with normal glucose tolerance was performed in Guangxi area of China. An odds ratio (OR) with its corresponding 95% confidence interval (CI) was used to assess the strengths of the association between genetic variation and GDM. After adjustment of age and pre-BMI, the logistic regression analysis showed that the rs2134095 was significantly associated with GDM risk (CC vs. TT/TC: adjusted OR = 0.71, 95% CI = 0.56–0.90) in all subjects, and this result remained highly significant after Bonferroni’s correction for multiple testing (P=0.004). The stratified analysis showed that rs2134095 was significantly associated with the risk of GDM among age > 30 years (adjusted OR = 0.61, 95% CI = 0.39–0.97), BMI > 22 kg/m² (adjusted OR = 0.46, 95% CI = 0.30–0.70), systolic blood pressure (SBP) > 120 mmHg (adjusted OR = 1.96, 95% CI = 1.14–3.36), glycosylated hemoglobin A1c (HbA1c) < 6.5% (adjusted OR = 1.41, 95% CI = 1.11–1.78), TG ≤ 1.7 mmol/l (adjusted OR = 2.57, 95% CI = 1.45–4.53), TC ≤ 5.18 mmol/l (adjusted OR = 1.58, 95% CI = 1.13–2.22), high-density lipoprotein cholesterol (HDL-c) ≤ 1.5 mmol/l (adjusted OR = 1.70, 95% CI = 1.16–2.49) and low-density lipoprotein cholesterol (LDL-c) > 3.12 mmol/l (adjusted OR = 1.47, 95% CI = 1.08–2.00) subjects, under the recessive genetic model. We also found that rs2134095 interacted with age (P_interaction=0.039), pre-BMI (P_interaction=0.040) and TG (P_interaction=0.025) influencing individual’s genetic susceptibility to GDM. The rs2134095 T>C is significantly associated with the risk of GDM by effect of a single locus and/or complex joint gene–gene and gene–environment interactions. Larger sample-size and different population studies are required to confirm the findings.

HLA Alleles Cw12 and DQ4 in Kidney Transplant Recipients Are Independent Risk Factors for the Development of Posttransplantation Diabetes

Supplemental Digital Content is available in the text.

The association between specific HLA alleles and risk for posttransplantation diabetes (PTDM) in a contemporary and multiethnic kidney transplant recipient cohort is not clear.

Meta-analysis: Interleukin 6 gene -174G/C polymorphism associated with type 2 diabetes mellitus and interleukin 6 changes

The gene coding interleukin 6 (IL‐6) is a promising candidate in predisposition to type 2 diabetes mellitus (T2DM). This study aimed to meta‐analytically examine the association of IL‐6 gene −174G/C polymorphism with T2DM and circulating IL‐6 changes across −174G/C genotypes. Odds ratio (OR) and standard mean difference (SMD) with 95% confidence interval (CI) were calculated. Twenty‐five articles were meta‐analysed, with 20 articles for T2DM risk and 9 articles for circulating IL‐6 changes. Overall, there was no detectable significance for the association between −174G/C polymorphism and T2DM, and this association was relatively obvious under dominant model (OR: 0.82, 95% CI: 0.56‐1.21). Improved heterogeneity was seen in some subgroups, with statistical significance found in studies involving subjects of mixed races (OR: 0.63, 95% CI: 0.46‐0.86). Begg's and filled funnel plots, along with Egger's tests revealed week evidence of publication bias. In genotype‐phenotype analyses, carriers of −174CC and −174CG genotypes separately had 0.10 and 0.03 lower concentrations (pg/mL) of circulating IL‐6 than −174GG carriers. Albeit no detectable significance for the association of −174G/C with T2DM, our findings provided suggestive evidence on a dose‐dependent relation between −174G/C mutant alleles and circulating IL‐6 concentrations, indicating possible implication of this polymorphism in the pathogenesis of T2DM.

Lactonase activity and status of paraoxonase 1 and oxidative stress in neonates of women with gestational diabetes mellitus

BACKGROUND

The level and lactonase activity of paraoxonase 1 (PON1) and their association with PON1 genetic variants and oxidative stress are unclear in neonates of women with gestational diabetes mellitus (GDM).

METHODS

This study included 362 neonates of women with GDM and 302 control neonates. The level, lactonase activity, normalized lactonase activity (NLA), and genetic polymorphisms of PON1, serum total oxidant status (TOS), total antioxidant capacity (TAC), and malondialdehyde (MDA) were analyzed.

RESULTS

The neonates of the women with GDM had significantly higher levels, lactonase activity, and NLA of PON1, higher TOS, TAC, and MDA concentrations, and relatively higher oxidative stress index than those of the control neonates. The PON1 -108C → T variation decreased the lactonase activity, level, and NLA of PON1, while the PON1 192Q → R variation decreased the PON1 NLA in a genotype-dependent manner in the two groups. Multivariable regression analysis revealed the PON1 -108C/T or 192Q/R variation, apolipoprotein (apo)A1, or apoB as significant predictors of the level, lactonase activity, and NLA of PON1.

CONCLUSIONS

The lactonase activity, level, and NLA of PON1 were increased in the neonates of women with GDM. The PON1 genetic variants, abnormalities in lipoproteins, and increased oxidative stress may be associated with these changes.

IMPACT

This is the first study to report the elevated level, lactonase activity, and NLA of PON1 in the neonates of women with GDM. These neonates also exhibited increased oxidative stress and an adverse glycolipid metabolic profile. We further established that the -108C/T and/or 192Q/R genetic variants of the PON1 gene, abnormalities in lipoprotein metabolism, and/or increased oxidative stress had noticeable influences on the level and activities of PON1. Whether these changes potentially cause metabolic disorders later in life remains to be determined. Therefore, the neonates born to women with GDM require further clinical follow-ups.

Common Variants in NUS1 and GP2 Genes Contributed to the Risk of Gestational Diabetes Mellitus

BACKGROUND

Recently, NUS1 and GP2 genes were reported to be associated with the risk of type 2 diabetes (T2D) in a Japanese population. Given the sharing of pathogenic contribution from genetic factors between T2D and gestational diabetes mellitus (GDM), we conducted the study to systematically examine the relationship of NUS1 and GP2 genes with the susceptibility to GDM in Chinese Han population.

METHODS

A total of 4,250 subjects comprised of 1,282 patients with GDM and 2,968 controls were recruited, and 20 tag single nucleotide polymorphisms (SNPs) (10 from NUS1 and 10 from GP2) were selected for genotyping. Association analyses were conducted for GDM and its related biomedical indexes including fasting glucose and HbA1c levels.

RESULTS

Two SNPs, rs80196932 from NUS1 (P=2.93×10^-5) and rs117267808 from GP2 (P=5.68×10^-5), were identified to be significantly associated with the risk of GDM. Additionally, SNP rs80196932 was significantly associated with HbA1c level in both patients with GDM (P=0.0009) and controls (P=0.0003), while SNP rs117267808 was significantly associated with fasting glucose level in both patients with GDM (P=0.0008) and controls (P=0.0007). Serum levels of protein NUS1 and GP2 were measured for the study subjects, and significant differences were identified among groups with different genotypes of SNP rs80196932 and rs117267808, respectively.

CONCLUSIONS

Our findings indicate that NUS1 and GP2 genes contribute to the risk of GDM, which would help to offer the potential to improve our understanding of the etiology of GDM and, in turn, could facilitate the development of novel medicines and treatments for GDM.

Exposure to maternal diabetes induces endothelial dysfunction and hypertension in adult male rat offspring

The adverse environment in early life can modulate adult phenotype, including blood pressure. Our previous study shows, in a rat streptozotocin (STZ)-induced maternal diabetes model, fetal exposure to maternal diabetes is characterized by established hypertension in the offspring. However, the exact mechanisms are not known. Our present study found, as compared with male control mother offspring (CMO), male diabetic mother offspring (DMO) had higher blood pressure with arterial dysfunction, i.e., decreased acetylcholine (Ach)-induced vasodilation. But there is no difference in blood pressure between female CMO and DMO. The decreased Ach-induced vasodilation was related to decreased nitric oxide (NO) production in the endothelium, not NO sensitivity in vascular smooth muscle because sodium nitroprusside (SNP)-mediated vasodilation was preserved; there was decreased NO production and lower eNOS phosphorylation in male DMO. The reactive oxygen species (ROS) level was increased in male DMO than CMO; normalized ROS levels with tempol increased NO production, normalized Ach-mediated vasodilation, and lowered blood pressure in male DMO rats. It indicates that diabetic programming hypertension is related to arterial dysfunction; normalizing ROS might be a potential strategy for the prevention of hypertension in the offspring.

Genetic Loci and Physiologic Pathways Involved in Gestational Diabetes Mellitus Implicated Through Clustering

Hundreds of common genetic variants acting through distinguishable physiologic pathways influence the risk of type 2 diabetes (T2D). It is unknown to what extent the physiology underlying gestational diabetes mellitus (GDM) is distinct from that underlying T2D. In this study of >5,000 pregnant women from three cohorts, we aimed to identify physiologically related groups of maternal variants associated with GDM using two complementary approaches that were based on Bayesian nonnegative matrix factorization (bNMF) clustering. First, we tested five bNMF clusters of maternal T2D-associated variants grouped on the basis of physiology outside of pregnancy for association with GDM. We found that cluster polygenic scores representing genetic determinants of reduced β-cell function and abnormal hepatic lipid metabolism were associated with GDM; these clusters were not associated with infant birth weight. Second, we derived bNMF clusters of maternal variants on the basis of pregnancy physiology and tested these clusters for association with GDM. We identified a cluster that was strongly associated with GDM as well as associated with higher infant birth weight. The effect size for this cluster's association with GDM appeared greater than that for T2D. Our findings imply that the genetic and physiologic pathways that lead to GDM differ, at least in part, from those that lead to T2D.

Polymorphisms of TGF-β1 and TGF-β3 in Chinese women with gestational diabetes mellitus

Background

Gestational diabetes mellitus (GDM) is a pregnancy-specific carbohydrate intolerance Which can cause a large number of perinatal and postpartum complications. The members of Transforming growth factor-β (TGF-β) superfamily play key roles in the homeostasis of pancreatic β-cell and may involve in the development of GDM. This study aimed to explore the association between the polymorphisms of TGF-β1, TGF-β3 and the risk to GDM in Chinese women.

Methods

This study included 919 GDM patients (464 with preeclampsia and 455 without preeclampsia) and 1177 healthy pregnant women. TaqMan allelic discrimination real-Time PCR was used to genotype the TGF-β1 (rs4803455) and TGF-β3 (rs2284792 and rs3917201), The Hardy-Weinberg equilibrium (HWE) was evaluated by chi-square test.

Results

An increased frequency of TGF-β3 rs2284792 AA and AG genotype carriers was founded in GDM patients (AA vs. AG + GG: χ² = 6.314, P = 0.012, OR = 1.270, 95%CI 1.054–1.530; AG vs. GG + AA: χ² = 8.545, P = 0.003, OR = 0.773, 95%CI 0.650–0.919). But there were no significant differences in the distribution of TGF-β1 rs4803455 and TGF-β3 rs3917201 between GDM and healthy women. In addition, no significant differences were found in allele and genotype frequencies among GDM patients with preeclampsia (PE).

Conclusions

The AA and AG genotype of TGF-β3 rs2284792 polymorphism may be significantly associated with increased risk of GDM in Chinese population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-020-03459-w.

Defining Heterogeneity Among Women With Gestational Diabetes Mellitus

Attention to precision medicine in type 2 diabetes (T2D) has provided two favored approaches to subclassifying affected individuals and parsing heterogeneity apparent in this condition: phenotype-based and genotype-based. Gestational diabetes mellitus (GDM) shares phenotypic characteristics with T2D. However, unlike T2D, GDM emerges in the setting of profound pregnancy-related physiologic changes in glucose metabolism. T2D and GDM also share common genetic architecture, but there are likely to be unique genetic influences on pregnancy glycemic regulation that contribute to GDM. In this Perspective, we describe efforts to decipher heterogeneity in T2D and detail how we and others are applying approaches developed for T2D to the study of heterogeneity in GDM. Emerging results reveal the potential of phenotype- and genotype-based subclassification of GDM to deliver the promise of precision medicine to the obstetric population.

Perturbations of gut microbiota in gestational diabetes mellitus patients induce hyperglycemia in germ-free mice

Shifts in the maternal gut microbiota have been implicated in the development of gestational diabetes mellitus (GDM). Understanding the interaction between gut microbiota and host glucose metabolism will provide a new target of prediction and treatment. In this nested case-control study, we aimed to investigate the causal effects of gut microbiota from GDM patients on the glucose metabolism of germ-free (GF) mice. Stool and peripheral blood samples, as well as clinical information, were collected from 45 GDM patients and 45 healthy controls (matched by age and prepregnancy body mass index (BMI)) in the first and second trimester. Gut microbiota profiles were explored by next-generation sequencing of the 16S rRNA gene, and inflammatory factors in peripheral blood were analyzed by enzyme-linked immunosorbent assay. Fecal samples from GDM and non-GDM donors were transferred to GF mice. The gut microbiota of women with GDM showed reduced richness, specifically decreased Bacteroides and Akkermansia, as well as increased Faecalibacterium. The relative abundance of Akkermansia was negatively associated with blood glucose levels, and the relative abundance of Faecalibacterium was positively related to inflammatory factor concentrations. The transfer of fecal microbiota from GDM and non-GDM donors to GF mice resulted in different gut microbiota colonization patterns, and hyperglycemia was induced in mice that received GDM donor microbiota. These results suggested that the shifting pattern of gut microbiota in GDM patients contributed to disease pathogenesis.

The impact of sex on gene expression across human tissues

Many complex human phenotypes exhibit sex-differentiated characteristics. However, the molecular mechanisms underlying these differences remain largely unknown. We generated a catalog of sex differences in gene expression and in the genetic regulation of gene expression across 44 human tissue sources surveyed by the Genotype-Tissue Expression project (GTEx, v8 release). We demonstrate that sex influences gene expression levels and cellular composition of tissue samples across the human body. A total of 37% of all genes exhibit sex-biased expression in at least one tissue. We identify cis expression quantitative trait loci (eQTLs) with sex-differentiated effects and characterize their cellular origin. By integrating sex-biased eQTLs with genome-wide association study data, we identify 58 gene-trait associations that are driven by genetic regulation of gene expression in a single sex. These findings provide an extensive characterization of sex differences in the human transcriptome and its genetic regulation.

Precision medicine in diabetes: a Consensus Report from the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD)

The convergence of advances in medical science, human biology, data science and technology has enabled the generation of new insights into the phenotype known as 'diabetes'. Increased knowledge of this condition has emerged from populations around the world, illuminating the differences in how diabetes presents, its variable prevalence and how best practice in treatment varies between populations. In parallel, focus has been placed on the development of tools for the application of precision medicine to numerous conditions. This Consensus Report presents the American Diabetes Association (ADA) Precision Medicine in Diabetes Initiative in partnership with the European Association for the Study of Diabetes (EASD), including its mission, the current state of the field and prospects for the future. Expert opinions are presented on areas of precision diagnostics and precision therapeutics (including prevention and treatment) and key barriers to and opportunities for implementation of precision diabetes medicine, with better care and outcomes around the globe, are highlighted. Cases where precision diagnosis is already feasible and effective (i.e. monogenic forms of diabetes) are presented, while the major hurdles to the global implementation of precision diagnosis of complex forms of diabetes are discussed. The situation is similar for precision therapeutics, in which the appropriate therapy will often change over time owing to the manner in which diabetes evolves within individual patients. This Consensus Report describes a foundation for precision diabetes medicine, while highlighting what remains to be done to realise its potential. This, combined with a subsequent, detailed evidence-based review (due 2022), will provide a roadmap for precision medicine in diabetes that helps improve the quality of life for all those with diabetes.

Gestational Diabetes Mellitus: A Harbinger of the Vicious Cycle of Diabetes

Gestational diabetes mellitus (GDM), characterized by a transitory form of diabetes induced by insulin resistance and pancreatic β-cell dysfunction during pregnancy, has been identified as one of the major obstacles in achieving improved maternal and child health. Approximately 9-25% of pregnancies worldwide are impacted by the acute, long-term, and transgenerational health complications of this disease. Here, we discuss how GDM affects longstanding maternal and neonatal outcomes, as well as health risks that likely persist into future generations. In addition to the current challenges in the management and diagnosis of and the complications associated with GDM, we discuss current preclinical models of GDM to better understand the underlying pathophysiology of the disease and the timely need to increase our scientific toolbox to identify strategies to prevent and treat GDM, thereby advancing clinical care.

Precision Medicine in Diabetes: A Consensus Report From the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD)

The convergence of advances in medical science, human biology, data science, and technology has enabled the generation of new insights into the phenotype known as "diabetes." Increased knowledge of this condition has emerged from populations around the world, illuminating the differences in how diabetes presents, its variable prevalence, and how best practice in treatment varies between populations. In parallel, focus has been placed on the development of tools for the application of precision medicine to numerous conditions. This Consensus Report presents the American Diabetes Association (ADA) Precision Medicine in Diabetes Initiative in partnership with the European Association for the Study of Diabetes (EASD), including its mission, the current state of the field, and prospects for the future. Expert opinions are presented on areas of precision diagnostics and precision therapeutics (including prevention and treatment), and key barriers to and opportunities for implementation of precision diabetes medicine, with better care and outcomes around the globe, are highlighted. Cases where precision diagnosis is already feasible and effective (i.e., monogenic forms of diabetes) are presented, while the major hurdles to the global implementation of precision diagnosis of complex forms of diabetes are discussed. The situation is similar for precision therapeutics, in which the appropriate therapy will often change over time owing to the manner in which diabetes evolves within individual patients. This Consensus Report describes a foundation for precision diabetes medicine, while highlighting what remains to be done to realize its potential. This, combined with a subsequent, detailed evidence-based review (due 2022), will provide a roadmap for precision medicine in diabetes that helps improve the quality of life for all those with diabetes.

The impact of GSTM1 and GSTT1 polymorphisms on susceptibility to gestational diabetes in Iranian population

Background: Gestational diabetes mellitus (GDM) is characterized as a common metabolic disorder during pregnancy which is associated with glucose intolerance and insulin resistance. Genetic predisposition could contribute to the development of GDM.Methods: We conducted a case-control study to inspect the impact of GSTM1 and GSTT1 polymorphism on GDM susceptibility in Iranian population. The population consisted of 149 pregnant women with GDM as cases, and 138 healthy pregnant women without any history of GDM as controls. Polymerase chain reaction-restriction fragment length polymorphism method was applied to determine the GSTM1 and GSTT1 gene polymorphisms.Results: There were statistically significant differences between the cases and controls in terms of age (p = .005), BMI (p < .001), family history of gestational diabetes (p < .001), FBS (p = .001), TG (p ≤ .001), and HDL (p = .003). However, no significant differences were observed in TC (p = .078) and LDL (p = .062). There were significant differences between GSTM1 polymorphism (Null and present) in the case and controls groups [OR (95% CI); 2.3 (1.4-3.7), p < .001]. The distribution of GSTM1-null genotype was found to be significantly higher in GDM patients (68.6%) than the control group (48.5%). No significant variance was detected between GSTT1 polymorphism (Null and present) in the case and controls groups [OR (95% CI); 1.1 (0.6-1.6), p = .088]. The frequency of GSTM1 null/GSTT1 null [OR (95% CI); 2.7 (1.2-5.2), p = .01] and GSTM1 null/GSTT1 present [OR (95% CI); 2.6 (1.4-4.8), p = .002] genotypes significantly differed between the GDM and control groups.Conclusion: It seems that GSTM1 null genotype might be considered as GDM risk factor in Iranian population.

Common genetic variants in ADCY5 and gestational glycemic traits

Two meta-analysis of genome wide association studies identified two variants at adenylate cyclase 5 (ADCY5) associated with type 2 diabetes mellitus, fasting and 2-hour glucose in non-pregnant individuals of European descent. The objective of our study was to explore the role of common variants in ADCY5 on gestational glycemic traits, including plasma glucose, insulin values, β cell function and insulin resistance in the fasted state as well as plasma glucose 1 hour after a 50-gram glucose challenge test among Chinese Han women. Homoeostasis model assessment (HOMA) was used to quantify β cell function (HOMA1-β and HOMA2-β) and insulin resistance (HOMA1-IR and HOMA2-IR). Thirty-five single nucleotide polymorphisms (SNPs) in ADCY5 were genotyped in 929 unrelated Chinese Han women with singleton pregnancies. Three SNPs (rs6797915, rs9856662 and rs9875803) displayed evidence for association with plasma glucose 1 hour after a 50-gram glucose challenge test (P = 0.042, 0.018 and 0.018, respectively), one (rs6777397) displayed evidence for association with HOMA1-β (P = 0.014), and one (rs6762009) displayed evidence for association with HOMA1-IR (P = 0.033). These results provide additional insight into the effects of genetic variation within ADCY5 in glucose metabolism, especially during pregnancy and in non-European descent populations.

Novel Genetic Variants of PPARγ2 Promoter in Gestational Diabetes Mellitus and its Molecular Regulation in Adipogenesis

Peroxisome proliferator-activated receptor γ2 (PPARγ2) is a nuclear hormone receptor of ligand-dependent transcription factor with a key role in adipogenesis and insulin sensitization in diabetes mellitus. In this study, we investigated genetic variants in PPARγ2 promoter, its association with gestational diabetes mellitus (GDM), and its molecular regulation. PPARγ2 promoter and start codon (-2,091 to +82 bp) from 400 pregnancies with GDM and 400 gestational-age matched control pregnancies were sequenced. Association and linkage disequilibrium of the identified polymorphisms with GDM was determined. ChIP-seq, gene silencing, and dual-luciferase reporter assays were performed to confirm transcription factor binding sites and promoter activity of the variants. Transfection experiments were carried out to determine the effects of variants on gene expression and adipogenesis. Among 15 variants identified, 7 known variants were not significantly associated with the risk of GDM (odds ratio: 0.710-1.208, 95% confidence interval: 0.445-0.877 to 1.132-1.664, P > 0.05) while linkage disequilibrium was significant (D' > 0.7, R² > 0.9). However, T-A-A-T-G haplotype was not significantly associated with GDM (χ² = 2.461, P = 0.117). Five rare variants and 3 novel variants (rs948820149, rs1553638909, and rs1553638903) were only found in GDM. Transcription factor glucocorticoid receptor β (GRβ) bound to -807A/C (rs948820149) and knockdown of GRβ suppressed PPARγ2 promoter activity. This mutation significantly down-regulated PPARγ2 expression and alleviated adipogenesis. In conclusion, a novel -807A/C in PPARγ2 promoter was identified in Chinese women with GDM and the mutation affected GRβ binding and transcription of PPARγ2 for adipogenesis.

Omics-based biomarkers in the diagnosis of diabetes

Diabetes mellitus (DM) is a group of metabolic diseases related to the dysfunction of insulin, causing hyperglycaemia and life-threatening complications. Current early screening and diagnostic tests for DM are based on changes in glucose levels and autoantibody detection. This review evaluates recent studies on biomarker candidates in diagnosing type 1, type 2 and gestational DM based on omics classification, whilst highlighting the relationship of these biomarkers with the development of diabetes, diagnostic accuracy, challenges and future prospects. In addition, it also focuses on possible non-invasive biomarker candidates besides common blood biomarkers.

Serum growth differentiation factor 15 is associated with glucose metabolism in the third trimester in Chinese pregnant women

OBJECTIVE

Growth differentiation factor 15 (GDF15) has been demonstrated to increase in diabetes as a protective factor. However, studies assessing relationships between GDF15 levels and gestational diabetes mellitus (GDM) are limited. In this study, we aimed to investigate whether GDF15 levels are related to GDM in Chinese subjects.

METHODS

We included 200 GDM patients and 200 matched normal controls in the second trimester as well as 130 GDM patients and 130 matched normal controls in the third trimester. Serum GDF15 levels of all participants were determined using an enzyme-linked immunosorbent assay (ELISA). Then, according to GDF15 levels, we equally divided the participants in the second and third trimesters into four subgroups respectively. The relationships of serum GDF15 levels with glucolipid metabolism indicators were analyzed.

RESULTS

In the third trimester, GDF15 levels were significantly higher in the GDM patients than in the normal controls (P < 0.001). Additionally, fasting blood glucose (FBG), 1-h postprandial glucose (1h-PG), 2-h postprandial glucose (2h-PG), hemoglobin A1C (HbA1c) and area under curve of glucose (AUCG) from the 75-g oral glucose tolerance test (OGTT) were positively associated with GDF15 levels (P < 0.05), even after adjusting for age, pregestational BMI, changes of BMI until the third trimester, gestational age, twin and family history of diabetes. Moreover, GDF15 levels were higher in the third trimester than in the second trimester (P < 0.001). No significant relationships were found between GDF15 levels and glucolipid metabolism in the second trimester (P > 0.05).

CONCLUSIONS

Serum GDF15 levels were positively correlated with glucose metabolism in the third trimester in Chinese pregnant women.