Proteomic analysis of milk fat globule membrane proteins in mature human milk of women with and without gestational diabetes mellitus

Milk fat globule membrane proteins (MFGMP) in human milks have positive effects on infant's health. As gestational diabetes mellitus (GDM) causes variations in MFGMP, it is essential to understand the effects of GDMon MFGMP. This study aims to investigate and compare the MFGMP (>3 months postpartum) of GDM and non-GDM (NGDM) women using four-dimensional-data-independent-acquisition proteomics technology. Principal component analysis shows significant differences in the MFGMP of GDM and NGDM women. A total of 4747 MFGMP were identified in maturehuman milk of GDM and NGDM women. Among these proteins, 174 differentially expressed proteins (DEPs) were identified in MFGM of GDM and NGDM women. Albumin (FC = 7.96) and transthyretin (FC = 2.57) which are related to insulin resistance and involved in thyroid hormone synthesis, are significantly up-regulated in MFGMP of GDM mothers indicating insulin resistance, imbalance of glucose homeostasis and poor glucose metabolism might persist in postpartum period.

The role of hsa_circ_0042260/miR-4782-3p/LAPTM4A axis in gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is a common metabolic condition during pregnancy, posing risks to both mother and fetus. CircRNAs have emerged as important players in various diseases, including GDM. We aimed to investigate the role of newly discovered circRNA, hsa_circ_0042260, in GDM pathogenesis. Using GSE194119 dataset, hsa_circ_0042260 was identified and its expression in plasma, placenta, and HG-stimulated HK-2 cells was examined. Silencing hsa_circ_0042260 in HK-2 cells assessed its impact on cell viability, apoptosis, and inflammation. Bioinformatics analysis revealed downstream targets of hsa_circ_0042260, namely miR-4782-3p and LAPTM4A. The interaction between hsa_circ_0042260, miR-4782-3p, and LAPTM4A was validated through various assays. hsa_circ_0042260 was upregulated in plasma from GDM patients and HG-stimulated HK-2 cells. Silencing hsa_circ_0042260 improved cell viability, suppressed apoptosis and inflammation. Hsa_circ_0042260 interacted with miR-4782-3p, which exhibited low expression in GDM patient plasma and HG-stimulated cells. MiR-4782-3p targeted LAPTM4A, confirmed by additional assays. LAPTM4A expression increased in GDM patient plasma and HG-induced HK-2 cells following hsa_circ_0042260 knockdown or miR-4782-3p overexpression. In rescue assays, inhibition of miR-4782-3p or overexpression of LAPTM4A counteracted the effects of hsa_circ_0042260 downregulation on cell viability, apoptosis, and inflammation. In conclusion, the hsa_circ_0042260/miR-4782-3p/LAPTM4A axis plays a role in regulating GDM progression in HG-stimulated HK-2 cells.

Early-Pregnancy Serum Maternal and Placenta-Derived Exosomes miRNAs Vary Based on Pancreatic β-Cell Function in GDM

CONTEXT

Pancreatic β-cell function impairment is a key mechanism for developing gestational diabetes mellitus (GDM). Maternal and placental exosomes regulate maternal and placental responses during hyperglycemia. Studies have associated exosomal micro-RNAs (miRNAs) with GDM development. To date, no studies have been reported that evaluate the profile of miRNAs present in maternal and placental exosomes in the early stages of gestation from pregnancies that develop GDM.

OBJECTIVE

We assessed whether early-pregnancy serum maternal and placenta-derived exosomes miRNA profiles vary according to pancreatic β-cell function in women who will develop GDM.

METHODS

A prospective nested case-control study was used to identify exosomal miRNAs that vary in early-pregnancy stages (<18 weeks of gestation) from women with normoglycemia and those who developed GDM based on their pancreatic β-cell function using the homeostasis model assessment of pancreatic β-cell function (HOMA-%β) index. Early-pregnancy serum maternal and placenta-derived exosomes were isolated to obtain miRNA profiles. Potential target and pathway analyses were performed to identify molecular and metabolic pathways associated with the exosomal miRNAs identified.

RESULTS

In early-pregnancy stages, serum maternal exosome size and concentration are modified in GDM group and fluctuate according to HOMA-%β index. Serum maternal exosomal hsa-miR-149-3p and hsa-miR-455-3p in GDM are related to insulin secretion and signaling, lipolysis, and adipocytokine signaling. Early-pregnancy serum placenta-derived exosomes hsa-miR-3665 and hsa-miR-6727-5p in GDM are related to regulating genes involved in response to immunological tolerance of pregnancy and pathways associated with placental dysfunction.

CONCLUSION

Early serum exosomal miRNAs differ depending on their origin (maternal or placental) and pancreatic β-cell function. This research provides insights into the interactions between maternal and placental exosomal miRNAs and may have implications for identifying potential biomarkers or therapeutic targets for GDM.

DNA methylation signatures of youth-onset type 2 diabetes and exposure to maternal diabetes

OBJECTIVE

Youth-onset type 2 diabetes (T2D) is physiologically distinct from adult-onset, but it is not clear how the two diseases differ at a molecular level. In utero exposure to maternal type 2 diabetes (T2D) is known to be a specific risk factor for youth-onset T2D. DNA methylation (DNAm) changes associated with T2D but which differ between youth- and adult-onset might delineate the impacts of T2D development at different ages and could also determine the contribution of exposure to in utero diabetes.

METHODS

We performed an epigenome-wide analysis of DNAm on whole blood from 218 youth with T2D and 77 normoglycemic controls from the iCARE (improving renal Complications in Adolescents with type 2 diabetes through REsearch) cohort. Associations were tested using multiple linear regression models while adjusting for maternal diabetes, sex, age, BMI, smoking status, second-hand smoking exposure, cell-type proportions and genetic ancestry.

RESULTS

We identified 3830 differentially methylated sites associated with youth T2D onset, of which 3794 were moderately (adjusted p-value < 0.05 and effect size estimate > 0.01) associated and 36 were strongly (adjusted p-value < 0.05 and effect size estimate > 0.05) associated. A total of 3725 of these sites were not previously reported in the EWAS Atlas as associated with T2D, adult obesity or youth obesity. Moreover, three CpGs associated with youth-onset T2D in the PFKFB3 gene were also associated with maternal T2D exposure (FDR < 0.05 and effect size > 0.01). This is the first study to link PFKFB3 and T2D in youth.

CONCLUSION

Our findings support that T2D in youth has different impacts on DNAm than adult-onset, and suggests that changes in DNAm could provide an important link between in utero exposure to maternal diabetes and the onset of T2D.

Epigenetics of the non-coding RNA nc886 across blood, adipose tissue and skeletal muscle in offspring exposed to diabetes in pregnancy

BACKGROUND

Diabetes in pregnancy is associated with increased risk of long-term metabolic disease in the offspring, potentially mediated by in utero epigenetic variation. Previously, we identified multiple differentially methylated single CpG sites in offspring of women with gestational diabetes mellitus (GDM), but whether stretches of differentially methylated regions (DMRs) can also be identified in adolescent GDM offspring is unknown. Here, we investigate which DNA regions in adolescent offspring are differentially methylated in blood by exposure to diabetes in pregnancy. The secondary aim was to characterize the RNA expression of the identified DMR, which contained the nc886 non-coding RNA.

METHODS

To identify DMRs, we employed the bump hunter method in samples from young (9-16 yr, n = 92) offspring of women with GDM (O-GDM) and control offspring (n = 94). Validation by pyrosequencing was performed in an adult offspring cohort (age 28-33 years) consisting of O-GDM (n = 82), offspring exposed to maternal type 1 diabetes (O-T1D, n = 67) and control offspring (O-BP, n = 57). RNA-expression was measured using RT-qPCR in subcutaneous adipose tissue and skeletal muscle.

RESULTS

One significant DMR represented by 10 CpGs with a bimodal methylation pattern was identified, located in the nc886/VTRNA2-1 non-coding RNA gene. Low methylation status across all CpGs of the nc886 in the young offspring was associated with maternal GDM. While low methylation degree in adult offspring in blood, adipose tissue, and skeletal muscle was not associated with maternal GDM, adipose tissue nc886 expression was increased in O-GDM compared to O-BP, but not in O-T1D. In addition, adipose tissue nc886 expression levels were positively associated with maternal pre-pregnancy BMI (p = 0.006), but not with the offspring's own adiposity.

CONCLUSIONS

Our results highlight that nc886 is a metastable epiallele, whose methylation in young offspring is negatively correlated with maternal obesity and GDM status. The physiological effect of nc886 may be more important in adipose tissue than in skeletal muscle. Further research should aim to investigate how nc886 regulation in adipose tissue by exposure to GDM may contribute to development of metabolic disease.

Genetic polymorphisms associated with adverse pregnancy outcomes in nulliparas

Adverse pregnancy outcomes (APOs) affect a large proportion of pregnancies and represent an important cause of morbidity and mortality worldwide. Yet the pathophysiology of APOs is poorly understood, limiting our ability to prevent and treat these conditions. To search for genetic markers of maternal risk for four APOs, we performed multi-ancestry genome-wide association studies (GWAS) for pregnancy loss, gestational length, gestational diabetes, and preeclampsia. We clustered participants by their genetic ancestry and focused our analyses on three sub-cohorts with the largest sample sizes: European, African, and Admixed American. Association tests were carried out separately for each sub-cohort and then meta-analyzed together. Two novel loci were significantly associated with an increased risk of pregnancy loss: a cluster of SNPs located downstream of the TRMU gene (top SNP: rs142795512), and the SNP rs62021480 near RGMA. In the GWAS of gestational length we identified two new variants, rs2550487 and rs58548906 near WFDC1 and AC005052.1, respectively. Lastly, three new loci were significantly associated with gestational diabetes (top SNPs: rs72956265, rs10890563, rs79596863), located on or near ZBTB20, GUCY1A2, and RPL7P20, respectively. Fourteen loci previously correlated with preterm birth, gestational diabetes, and preeclampsia were found to be associated with these outcomes as well.

Lipids, apolipoproteins and gestational diabetes mellitus: a Mendelian randomization study

BACKGROUND

This study investigates the causal relationship between lipid traits and GDM in an effort to better understand the aetiology of GDM.

METHODS

Employing a two-sample Mendelian Randomization (MR) framework, we used Single Nucleotide Polymorphisms (SNPs) as instrumental variables to examine the impact of lipids and apolipoproteins on GDM. The research comprised univariable and multivariable MR analyses, with a prime focus on individual and combined effects of lipid-related traits. Statistical techniques included the fixed-effect inverse variance weighted (IVW) method and supplementary methods such as MR-Egger for comprehensive assessment.

RESULTS

Our findings revealed the following significant associations: apoA-I and HDL cholesterol were inversely correlated with GDM risk, while triglycerides showed a positive correlation. In multivariable analysis, apoA-I consistently exhibited a strong causal link with GDM, even after adjusting for other lipids and Body Mass Index (BMI).

CONCLUSION

The study demonstrates a significant causal relationship between apoA-I and GDM risk.

The associations of IGF2, IGF2R and IGF2BP2 gene polymorphisms with gestational diabetes mellitus: A case-control study

OBJECTIVE

To investigate the associations of Insulin-like growth factor-II (IGF2) gene, Insulin-like growth factor-II receptor (IGF2R) gene and Insulin-like growth factor-II binding protein 2 (IGF2BP2) gene polymorphisms with the susceptibility to gestational diabetes mellitus (GDM) in Chinese population.

METHODS

A total of 1703 pregnant women (835 GDM and 868 Non-GDM) were recruited in this case-control study. All participants underwent prenatal 75 g oral glucose tolerance test (OGTT) examinations during 24-28 gestational weeks at the Maternal and Child Health Hospital of Hubei Province from January 15, 2018 to March 31, 2019. Genotyping of candidate SNPs (IGF2 rs680, IGF2R rs416572, IGF2BP2 rs4402960, rs1470579, rs1374910, rs11705701, rs6777038, rs16860234, rs7651090) was performed on Sequenom MassARRAY platform. Logistic regression analysis was conducted to investigate the associations between candidate SNPs and risk of GDM. In addition, multifactor dimensionality reduction (MDR) method was applied to explore the effects of gene-gene interactions on GDM risk.

RESULTS

There were significant distribution differences between GDM group and non-GDM group in age, pre-pregnancy BMI, education level and family history of diabetes (P < 0.05). After adjusted for age, pre-pregnancy BMI, education level and family history of diabetes, there were no significant associations of the candidate SNPs polymorphisms and GDM risk (P > 0.05). Furthermore, there were no gene-gene interactions on the GDM risk among the candidate SNPs (P > 0.05). However, the fasting blood glucose (FBG) levels of rs6777038 CT carriers were significantly lower than TT carriers (4.69±0.69 vs. 5.03±1.57 mmol/L, P < 0.01), and the OGTT-2h levels of rs6777038 CC and CT genotype carriers were significantly lower than TT genotype carriers (8.10±1.91 and 8.08±1.87 vs. 8.99±2.90 mmol/L, P < 0.01).

CONCLUSIONS

IGF2 rs680, IGF2R rs416572, IGF2BP2 rs4402960, rs1470579, rs11705701, rs6777038, rs16860234, rs7651090 polymorphisms were not significantly associated with GDM risk in Wuhan, China. Further lager multicenter researches are needed to confirm these results.

MicroRNA-125b regulates vitamin D resistance by targeting CYP24A1 in the progression of gestational diabetes mellitus

Vitamin D deficiency is prevalent in pregnancy and has been associated with increased occurrences of preeclampsia, cesarean delivery, neonatal bacterial vaginosis, and gestational diabetes. CYP24A1, recognized as a key factor in vitamin D metabolism homeostasis, encodes 24-hydroxylase responsible for converting 25(OH)D3 and 1,25(OH)2D3 into inactive metabolites. Recently, we have reported CYP24A1 overexpression in patients with gestational diabetes mellitus (GDM) and trophoblast cells exposed to hyperglycemia. In this study, we explored miRNA-mediated regulation of CYP24A1 in GDM progression, validating our findings through silencing experiments in a trophoblast cell line. In silico tools identified miR-125b-5p as a putative target of CYP24A1. Expression analysis revealed downregulation of miR-125b-5p in blood samples from early GDM and GDM compared to healthy pregnant women, positively correlating with vitamin D levels. Hyperglycemic exposure in human trophoblastic cell lines (BeWo) decreased miR-125b-5p expression, concomitant with an increase in CYP24A1. To confirm the regulatory role of miR-125b on CYP24A1, we transfected BeWo cells with antimiR-125b or miR-125b mimic. AntimiR-125b transfection heightened CYP24A1 levels, while miR-125b mimic overexpression resulted in decreased CYP24A1 expression. These findings establish miR-125b as a regulator of CYP24A1. To explore the influence of miR-125b on vitamin D metabolism, trophoblast cells overexpressing miR-125b were treated with 0.1 and 1 µM calcitriol. Hyperglycemic conditions exhibited a reduction in CYP24A1 levels. Collectively, our results indicate that miR-125b may regulate vitamin D metabolism by targeting CYP24A1, contributing to GDM progression. These findings may pave the way for understanding vitamin D resistance in concurrent GDM development and identifying novel miRNAs targeting CYP24A1.

Does gestational diabetes mellitus increase the risk of cardiovascular disease? A Mendelian randomization study

PURPOSE

In recent years, epidemiological studies have revealed the relationship between gestational diabetes mellitus (GDM) and cardiovascular disease (CVD). In this study, we utilized Mendelian randomization (MR) to investigate the potential causal impact of GDM on cardiovascular disease for the first time.

METHODS

 We retrieved summary statistics from published genome-wide association studies. MR was first performed using significant SNPs extracted from the eighth data release of the FinnGen study. Next, a replication analysis for coronary artery disease (CAD) was conducted in another European ancestry population to validate our findings. Finally, mediation analysis was carried out to assess potential mediation effects.

RESULTS

Our data analysis revealed that genetically predicted GDM was significantly associated with increased CAD risk (OR 1.10, 95% CI 1.02-1.18, p 0.006). Replication analysis confirmed a significant genetic association between GDM and CAD (OR 1.07, 95% CI 1.02-1.12, p 0.003) in another European ancestry population. Mediation analysis indicated no significant mediation effect by type 2 diabetes mellitus (T2DM) on the GDM-CAD relationship (mediation effect β [95% CI]: 0.005 [-0.003, -0.017]).

CONCLUSION

Women with a prior history of GDM face an elevated risk of future CAD. This increased risk of CAD cannot be solely attributed to the subsequent onset of diabetes. Regular CAD risk assessment and primary prevention strategies are of paramount importance for women with a history of GDM.

Is there a causal association between gestational diabetes mellitus and immune mediators? A bidirectional Mendelian randomization analysis

Background

Diabetes that only appears or is diagnosed during pregnancy is referred to as gestational diabetes mellitus (GDM). The maternal physiological immune profile is essential for a positive pregnancy outcome. However, the causal relationship between GDM and immunophenotypes is not fully defined.

Methods

Based on the high-density genetic variation data at the genome-wide level, we evaluated the logical associations between 731 specific immune mediators and GDM using bidirectional Mendelian randomization (MR). The inverse variance weighted (IVW) was the main method employed for MR analysis. We performed multiple methods to verify the robustness and dependability of the MR results, and sensitivity measures were applied to rule out potential heterogeneity and horizontal pleiotropy.

Results

A substantial causal association between several immune mediators and GDM was detected. After FDR testing, HLA DR++ monocyte %leukocyte and HLA DR on plasmacytoid DC were shown to increase the risk of GDM; in contrast, CD127 on CD28+ CD45RA+ CD8br and CD19 on PB/PC were shown to attenuate the effect of GDM. Moreover, the progression of GDM has been shown to decrease the maternal levels of CD39+ activated Treg AC, CD39+ activated Treg %CD4 Treg, CD39+ resting Treg AC, CD39+ resting Treg %CD4 Treg, and CD39+ CD8BR %T cell.

Conclusions

Our findings support a possible causal association between GDM and various immunophenotypes, thus facilitating the provision of multiple options for preventive recognition as well as for the diagnostic and therapeutic management of GDM in clinical practice.

Genetic and inflammatory factors underlying gestational diabetes mellitus: a review

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

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.

RNA-seq analysis-based study on the effects of gestational diabetes mellitus on macrosomia

Background

Both the mother and the infant are negatively impacted by macrosomia. Macrosomia is three times as common in hyperglycemic mothers as in normal mothers. This study sought to determine why hyperglycemic mothers experienced higher macrosomia. Methods: Hematoxylin and Eosin staining was used to detect the placental structure of normal mother(NN), mothers who gave birth to macrosomia(NM), and mothers who gave birth to macrosomia and had hyperglycemia (DM). The gene expressions of different groups were detected by RNA-seq. The differentially expressed genes (DEGs) were screened with DESeq2 R software and verified by qRT-PCR. The STRING database was used to build protein-protein interaction networks of DEGs. The Cytoscape was used to screen the Hub genes of the different group.

Results

The NN group's placental weight differed significantly from that of the other groups. The structure of NN group's placenta is different from that of the other group, too. 614 and 3207 DEGs of NM and DM, respectively, were examined in comparison to the NN group. Additionally, 394 DEGs of DM were examined in comparison to NM. qRT-PCR verified the results of RNA-seq. Nucleolar stress appears to be an important factor in macrosomia, according on the results of KEGG and GO analyses. The results revealed 74 overlapped DEGs that acted as links between hyperglycemia and macrosomia, and 10 of these, known as Hub genes, were key players in this process. Additionally, this analysis believes that due of their close connections, non-overlapping Hubs shouldn't be discounted.

Conclusion

In diabetic mother, ten Hub genes (RPL36, RPS29, RPL8 and so on) are key factors in the increased macrosomia in hyperglycemia. Hyperglycemia and macrosomia are linked by 74 overlapping DEGs. Additionally, this approach contends that non-overlapping Hubs shouldn't be ignored because of their tight relationships.

Sex-Specific Alterations in Placental Proteomics Induced by Intrauterine Hyperglycemia

Gestational diabetes mellitus (GDM) with intrauterine hyperglycemia induces a series of changes in the placenta, which have adverse effects on both the mother and the fetus. The aim of this study was to investigate the changes in the placenta in GDM and its gender differences. In this study, we established an intrauterine hyperglycemia model using ICR mice. We collected placental specimens from mice before birth for histological observation, along with tandem mass tag (TMT)-labeled proteomic analysis, which was stratified by sex. When the analysis was not segregated by sex, the GDM group showed 208 upregulated and 225 downregulated proteins in the placenta, primarily within the extracellular matrix and mitochondria. Altered biological processes included cholesterol metabolism and oxidative stress responses. After stratification by sex, the male subgroup showed a heightened tendency for immune-related pathway alterations, whereas the female subgroup manifested changes in branched-chain amino acid metabolism. Our study suggests that the observed sex differences in placental protein expression may explain the differential impact of GDM on offspring.

TCF7L2 Polymorphism rs7903146 (C/T) and Gestational Diabetes Influence on Obstetric Outcome: A Romanian Case-Control Study

Gestational diabetes mellitus (GDM) is one of the most frequent predictors of obstetric outcome among Romanian pregnant women. Thus, we aimed to investigate the role of rs7903146 (C/T) TCF7L2 gene polymorphism in the presence of GDM and to evaluate the influence on maternal-fetal outcomes in a cohort of pregnant women from Northern Transylvania. Our prospective case-control study was performed in a tertiary maternity center on 61 patients diagnosed with GDM and 55 normal pregnant patients. The patients were genotyped for rs7903146 (C/T) polymorphism of the TCF7L2 gene using the PCR-RFLP method between 24 and 28 weeks of gestation. The minor T allele was associated with a high risk of developing GDM (OR 1.71 [95% CI 0.82-3.59]) if both heterozygote and homozygote types were considered. Also, a higher risk of developing GDM was observed in homozygous carriers (OR 3.26 [95% CI 1.10-9.68]). Women with the TT genotype were more likely to require insulin therapy during pregnancy than other genotypes with a 5.67-fold increased risk ([1.61-19.97], p = 0.015). TT homozygote type was significantly associated with fetal macrosomia for birth weights greater than the 95th percentile (p = 0.034). The homozygous TT genotype is associated with an increased risk of developing GDM. Also, rs7903146 (C/T) TCF7L2 variant is accompanied by a high probability of developing insulin-dependent gestational diabetes mellitus (ID-GDM). The presence of at least one minor T allele was associated with a higher risk of fetal macrosomia.

Causal relationship between gestational diabetes and preeclampsia: A bidirectional mendelian randomization analysis

AIMS

The study aimed to explore the potential causal link between gestational diabetes mellitus (GDM) and preeclampsia (PE) using a bidirectional mendelian randomization (MR) analysis.

MATERIALS

We conducted a bidirectional MR analysis to investigate the causal relationship between GDM and PE. Data from public genome-wide association studies (GWAS) for GDM and PE were obtained from the FinnGen consortium. Various MR methods were employed, including inverse-variance weighted (IVW), MR-Egger, and sensitivity analyses. Additionally, a knowledge-based approach identified genes underlying this potential connection.

RESULTS

The IVW method revealed a lack of significant association between GDM and PE (OR: 1.04, 95 % CI: 0.96-1.14; p = 0.275). Conversely, IVW analysis indicated a causal connection from PE to GDM (OR: 1.14, 95 % CI: 1.06-1.23; p < 0.001). Molecular pathway analysis identified 20 key genes, including ASAP2, central to the PE-GDM relationship. Tissue enrichment analysis showed pertinent gene expression in significant tissues. Moreover, lower ASAP2 expression was detected in PE patients' placentas.

CONCLUSIONS

Our bidirectional MR analysis offers evidence supporting a causal link between PE and GDM, elucidating their interconnected pathogenesis. Genetic and knowledge-based insights facilitate a deeper comprehension of these complex pregnancy complications.

MicroRNA Associations with Preterm Labor-A Systematic Review

This systematic review delves into the connections between microRNAs and preterm labor, with a focus on identifying diagnostic and prognostic markers for this crucial pregnancy complication. Covering studies disseminated from 2018 to 2023, the review integrates discoveries from diverse pregnancy-related scenarios, encompassing gestational diabetes, hypertensive disorders and pregnancy loss. Through meticulous search strategies and rigorous quality assessments, 47 relevant studies were incorporated. The synthesis highlights the transformative potential of microRNAs as valuable diagnostic tools, offering promising avenues for early intervention. Notably, specific miRNAs demonstrate robust predictive capabilities. In conclusion, this comprehensive analysis lays the foundation for subsequent research, intervention strategies and improved outcomes in the realm of preterm labor.

Non-alcoholic fatty liver disease and gestational diabetes mellitus: a bidirectional two-sample mendelian randomization study

PURPOSE

Previous observational studies have revealed a potential link between non-alcoholic fatty liver disease (NAFLD) and gestational diabetes mellitus (GDM), but their causal relationship remains unclear. Thus, this study aimed to examine whether a causal link exists between genetically determined NAFLD and GDM.

METHODS

Utilizing publicly accessible genome-wide association studies (GWAS), a two-sample bidirectional Mendelian randomization (MR) analysis was conducted. The GWASs data pertaining to NAFLD and GDM were obtained from the UK Biobank Consortium and FinnGen database in primary analysis, respectively. The random-effects inverse variance weighted (IVW) method was utilized as primary analysis method. Several sensitivity analyses were utilized to verify the robustness of the results. Additionally, we also analyzed the causal effect of potential shared influencing factors on these two conditions.

RESULTS

The result of the IVW method showed that there was no significant causal relationship between genetically determined NAFLD and GDM (OR = 0.98, 95% CI: 0.90-1.07, P = 0.691). Similarly, our reverse MR analysis failed to detect a significant causal effect of GDM on NAFLD (OR = 1.14, 95% CI: 0.97-1.36, P = 0.118). Sensitivity analyses further confirmed the robustness of the results. Moreover, we found that genetically determined body mass index, waist-to-hip ratio, triglycerides, and television viewing time may be positively correlated with NAFLD and GDM, while high-density lipoprotein cholesterol and apolipoprotein A-I may both be negatively correlated with NAFLD and GDM.

CONCLUSIONS

The current bidirectional MR study failed to provide sufficient genetic evidence for the causal relationship between NAFLD and GDM.

Distinct and shared genetic architectures of gestational diabetes mellitus and type 2 diabetes

Gestational diabetes mellitus (GDM) is a common metabolic disorder affecting more than 16 million pregnancies annually worldwide1,2. GDM is related to an increased lifetime risk of type 2 diabetes (T2D)1-3, with over a third of women developing T2D within 15 years of their GDM diagnosis. The diseases are hypothesized to share a genetic predisposition1-7, but few studies have sought to uncover the genetic underpinnings of GDM. Most studies have evaluated the impact of T2D loci only8-10, and the three prior genome-wide association studies of GDM11-13 have identified only five loci, limiting the power to assess to what extent variants or biological pathways are specific to GDM. We conducted the largest genome-wide association study of GDM to date in 12,332 cases and 131,109 parous female controls in the FinnGen study and identified 13 GDM-associated loci, including nine new loci. Genetic features distinct from T2D were identified both at the locus and genomic scale. Our results suggest that the genetics of GDM risk falls into the following two distinct categories: one part conventional T2D polygenic risk and one part predominantly influencing mechanisms disrupted in pregnancy. Loci with GDM-predominant effects map to genes related to islet cells, central glucose homeostasis, steroidogenesis and placental expression.

Changes of miR-139-5p, TGFB1, and COL1A1 in the placental tissue of cases with gestational diabetes mellitus

There are structural changes in the placenta of cases with Gestational Diabetes Mellitus (GDM). TGF-β and collagen pathways have crucial roles in tissue remodeling and TGF-β1 and COL1A1 are important genes in these signalling respectively. Also, lncRNA NEAT1, and miRNA hsa-miR-139-5p and hsa-miR-129-5p have regulatory effects on TGF-β1 and COL1A1. Here we aimed to assess their expressions in the placenta tissue of GDM cases. 30 patients with GDM and 30 healthy pregnant women participated in the study. Placental tissues taken during normal or cesarean delivery were used and total RNA was isolated from the tissues. mRNA levels were determined by qPCR and protein levels were determined by ELISA methods. An in silico analysis was done to elucidate the possible relation of TGF-β1 and COL1A1 gene networks with GDM. We determined that NEAT1 and miR-129-5p expression levels did not differ between GDM and healthy control groups (p = 0.697 and 0.412, respectively). But, miR-139-5p mRNA level, TGFB1 and COL1A1 protein levels significantly differ between the GDM and control groups (p = 0.000, p = 0.000 and p = 0.001, respectively). The in silico analysis revealed that TGFB1 and COL1A1 genes network may have important role in the GDM with their variety of members and regulatory molecules NEAT1, hsa-miR-139-5p, and hsa-miR-129-5p can control their functions. The expression of TGFB1, COL1A1 and miR-139-5p is changed in placenta tissue of GDM cases and many genes in the interacting networks of TGFB1 and COL1A1 could contribute to the pathogenicity of GDM.

Investigating the Potential Mechanisms of Ferroptosis and Autophagy in the Pathogenesis of Gestational Diabetes

Ferroptosis and autophagy are two different cellular processes that have recently been highlighted for their potential roles in the pathogenesis and progression of gestational diabetes (GD). This research sought to uncover the crucial genes tied to ferroptosis and autophagy in GD, further investigating their mechanisms. Differentially expressed genes (DEGs) linked to ferroptosis and autophagy in GD were identified using publicly available data. Pathway enrichment, protein interactions, correlation with immune cell infiltration, and diagnostic value of DEGs were analyzed. HTR-8/SVneo cells were subjected to varying glucose levels to evaluate cell viability and the expression of markers related to ferroptosis and proteins associated with autophagy. Crucial DEGs were validated in vitro. A total of 12 DEGs associated with ferroptosis and autophagy in GD were identified, enriched in the PI3K-AKT signaling pathway. These genes exhibited significant correlations with monocyte infiltration, resting CD4 memory T cells, and follicular helper T cells. They exhibited high diagnostic value for GD (AUC: 0.77-0.97). High glucose treatment inhibited cell viability, induced ferroptosis, and activated autophagy in HTR-8/SVneo cells. Validation confirmed altered expression of SNCA, MTDH, HMGB1, TLR4, SOX2, SESN2, and HMOX1 after glucose treatments. In conclusion, ferroptosis and autophagy may play a role in GD development through key genes (e.g., TLR4, SOX2, SNCA, HMOX1, HMGB1). These genes could serve as promising biomarkers for GD diagnosis.

Body composition and risk of gestational diabetes mellitus: A univariable and multivariable Mendelian randomization study

OBJECTIVE

In this study, we employed a Mendelian randomization (MR) approach to investigate the independent causal associations of six body composition traits with gestational diabetes mellitus (GDM).

METHODS

Genome-wide significant levels (P < 10 × 5-8 ) of single nucleotide polymorphisms associated with body water mass, total protein, whole body fat-free mass, weight, whole body fat mass, and body fat percentage were used as instrumental variables. Data on GDM were obtained from the FinnGen Consortium, and both univariable and multivariable Mendelian randomization were performed. We utilized five different analytical methods including inverse-variance weighted (IVW), MR Egger, weighted median, simple mode, and weighted mode to assess the robustness of the results.

RESULTS

With univariable Mendelian randomization, the risk of GDM increased per 1-standard deviation (SD) increase in weight (ORweight  = 1.297, P = 3.06 × 10-5 ), whole body fat mass (ORwhole body fat mass  = 1.408, P = 1.32 × 10-6 ), and the risk of GDM increased per percent increase in body fat percentage (ORbody fat percentage  = 1.661, P = 1.01 × 10-8 ). Total protein had a protective effect on the risk of GDM (ORtotal protein  = 0.880, P = 0.048). However, there was no significant causal association between increases in body water mass and whole body fat-free mass per SD and the risk of GDM. Causal associations between weight, whole body fat mass, body fat percentage, and total protein with GDM were reduced to null in multivariable Mendelian randomization.

CONCLUSION

The present study furnishes genetic evidence to elucidate the causal relationship between body composition traits and GDM. Additionally, further studies are imperative to establish a causal connection between body composition traits and gestational diabetes mellitus.

A retrospective cohort study evaluating pregnancy outcomes in women with MIDD

AIMS

The most common pathogenic mitochondrial mutation associated with mitochondrial disease is m.3243A>G. Increased obstetric complications, such as spontaneous abortion, gestational diabetes (GDM), preterm delivery, and preeclampsia, have been reported in women carrying this mutation. We aimed to determine the fetal and maternal outcomes in pregnant women with mitochondrial disease.

METHODS

We retrospectively studied the obstetric and perinatal outcomes in 88 pregnancies of 26 women with genetically confirmed mitochondrial disease (m.3243A>G in the MTTL1 gene (n = 25); m.12258C>A in the MT-TS2 gene (n = 1)). Outcomes included pregnancy related complications, mode of delivery, gestational age at delivery and birthweight.

RESULTS

Mean heteroplasmy rate was 18%. The miscarriage rate was higher than background at 25%. 21 pregnancies (24%) were complicated by GDM; 9 pregnancies (13.6%) had a preterm delivery and 2 of them (3%) an extreme premature delivery < 32 weeks. One woman had preeclampsia and one had a postpartum hemorrhage. The caesarean section (CS) rate was 20%. For every unit increase in maternal heteroplasmy levels there was a 26% increased risk of undergoing an assisted operative vaginal delivery (OR 1.26, 95% CI 1.04-1.53, P = 0.002, Bonferroni corrected P = 0.005) and an 18% increased risk of undergoing a CS (OR 1.18, 95% CI 1.01-1.39, P = 0.01, Bonferroni corrected P = 0.03) compared to a spontaneous vaginal delivery. There was a statistical significant correlation between maternal and offspring heteroplasmy levels. Spearman correlation rho = 0.96, 95% CI 0.78-0.99, P = 0.0002.

CONCLUSION

Women with mitochondrial disease appear to have more frequent obstetric complications including miscarriage and GDM. Pre-pregnancy diagnosis of m.3243A>G will enable the counseling of women and increase awareness of possible obstetric complications.

Review of Genetic and Artificial Intelligence approaches to improving Gestational Diabetes Mellitus Screening and Diagnosis in sub-Saharan Africa

Background: Adverse outcomes from gestational diabetes mellitus (GDM) in the mother and newborn are well established. Genetic variants may predict GDM and Artificial Intelligence (AI) can potentially assist with improved screening and early identification in lower resource settings. There is limited information on genetic variants associated with GDM in sub-Saharan Africa and the implementation of AI in GDM screening in sub-Saharan Africa is largely unknown. Methods: We reviewed the literature on what is known about genetic predictors of GDM in sub-Saharan African women. We searched PubMed and Google Scholar for single nucleotide polymorphisms (SNPs) involved in GDM predisposition in a sub-Saharan African population. We report on barriers that limit the implementation of AI that could assist with GDM screening and offer possible solutions. Results: In a Black South African cohort, the minor allele of the SNP rs4581569 existing in the PDX1 gene was significantly associated with GDM. We were not able to find any published literature on the implementation of AI to identify women at risk of GDM before second trimester of pregnancy in sub-Saharan Africa. Barriers to successful integration of AI into healthcare systems are broad but solutions exist. Conclusions: More research is needed to identify SNPs associated with GDM in sub-Saharan Africa. The implementation of AI and its applications in the field of healthcare in the sub-Saharan African region is a significant opportunity to positively impact early identification of GDM.

The integrated bioinformatic analysis identifies immune microenvironment-related potential biomarkers for patients with gestational diabetes mellitus

Background

Gestational diabetes mellitus (GDM), a transient disease, may lead to short- or long-term adverse influences on maternal and fetal health. Therefore, its potential functions, mechanisms and related molecular biomarkers must be comprehended for the control, diagnosis and treatment of GDM.

Methods

The differentially expressed genes (DEGs) were identified using GSE49524 and GSE87295 associated with GDM from the Gene Expression Omnibus database, followed by function enrichment analysis, protein-protein interactions network construction, hub DEGs mining, diagnostic value evaluation and immune infiltration analysis. Finally, hub DEGs, the strongest related to immune infiltration, were screened as immune-related biomarkers.

Results

A hundred and seven DEGs were identified between patients with GDM and healthy individuals. Six hub genes with high diagnostic values, including ALDH1A1, BMP4, EFNB2, MME, PLAUR and SLIT2, were identified. Among these, two immune-related genes (PLAUR and SLIT2) with the highest absolute correlation coefficient were considered immune-related biomarkers in GDM.

Conclusion

Our study provides a comprehensive analysis of GDM, which would provide a foundation for the development of diagnosis and treatment of GDM.

DNA methylation risk score for type 2 diabetes is associated with gestational diabetes

BACKGROUND

Gestational diabetes mellitus (GDM) and type 2 diabetes mellitus (T2DM) share many pathophysiological factors including genetics, but whether epigenetic marks are shared is unknown. We aimed to test whether a DNA methylation risk score (MRS) for T2DM was associated with GDM across ancestry and GDM criteria.

METHODS

In two independent pregnancy cohorts, EPIPREG (n = 480) and EPIDG (n = 32), DNA methylation in peripheral blood leukocytes was measured at a gestational age of 28 ± 2. We constructed an MRS in EPIPREG and EPIDG based on CpG hits from a published epigenome-wide association study (EWAS) of T2DM.

RESULTS

With mixed models logistic regression of EPIPREG and EPIDG, MRS for T2DM was associated with GDM: odd ratio (OR)[95% CI]: 1.3 [1.1-1.8], P = 0.002 for the unadjusted model, and 1.4 [1.1-1.7], P = 0.00014 for a model adjusted by age, pre-pregnant BMI, family history of diabetes and smoking status. Also, we found 6 CpGs through a meta-analysis (cg14020176, cg22650271, cg14870271, cg27243685, cg06378491, cg25130381) associated with GDM, and some of their methylation quantitative loci (mQTLs) were related to T2DM and GDM.

CONCLUSION

For the first time, we show that DNA methylation marks for T2DM are also associated with GDM, suggesting shared epigenetic mechanisms between GDM and T2DM.

MTNR1B gene variations and high pre-pregnancy BMI increase gestational diabetes mellitus risk in Chinese women

AIM

To investigate the association of melatonin receptor 1B (MTNR1B) gene variations and pre-pregnancy body mass index (BMI) with gestational diabetes mellitus (GDM).

MATERIALS AND METHOD

In this study, 1566 Chinese Han pregnant women were enrolled and multiple genetic models were used to evaluate the association between MTNR1B gene polymorphisms and the risk of GDM. The clinical value of pre-pregnancy BMI in predicting GDM was analyzed and evaluated using receiver operating characteristic (ROC) curves. Several methods of analysis were used to examine the impact of gene-gene and gene-BMI interactions on the incidence of GDM influence.

RESULTS

For the MTNR1B gene, rs1387153 (C > T), rs10830962 (C > G), rs4753426 (T > C), and rs10830963 (C > G) are all risk mutations associated with the susceptibility of GDM. The ROC curve analysis indicated that the BMI demonstrated an area under the curve (AUC) of 0.595. Alongside, the sensitivity and specificity stood at 0.676 and 0.474 respectively. The maximum Joden index was found to be 0.150, with a corresponding critical BMI value of 20.5691 kg/m2. Interaction analysis revealed that gene-gene and gene-BMI interactions had no significant effect on GDM occurrence.

CONCLUSION

MTNR1B genetic variations confers the risk to GDM in Chinese women. Furthermore, the high pre-pregnancy BMI (≥20.5691 kg/m2) significantly increases the risk of GDM in Chinese women.

Investigating the causal impact of polycystic ovary syndrome on gestational diabetes mellitus: a two-sample Mendelian randomization study

Introduction

Determining the causal relationship between polycystic ovary syndrome (PCOS) and gestational diabetes mellitus (GDM) holds significant implications for GDM prevention and treatment. Despite numerous observational studies suggesting an association between PCOS and GDM, it remains unclear whether a definitive causal relationship exists between these two conditions and which specific features of PCOS contribute to increased incidence of GDM.

Methods

The causal relationship between polycystic ovary syndrome (PCOS), its characteristic indices, and gestational diabetes mellitus (GDM) was investigated using a two-sample Mendelian randomization study based on publicly available statistics from genome-wide association studies (GWAS). The inverse-variance weighted method was employed as the primary analytical approach to examine the association between PCOS, its characteristic indices, and GDM. MR Egger intercept was used to assess pleiotropy, while Q values and their corresponding P values were utilized to evaluate heterogeneity. It is important to note that this study adopts a two-sample MR design where PCOS and its characteristic indices are considered as exposures, while GDM is treated as an outcome.

Results

The study results indicate that there is no causal relationship between PCOS and GDM (all methods P > 0.05, 95% CI of OR values passed 1). The IVW OR value was 1.007 with a 95% CI of 0.906 to 1.119 and a P value of 0.904. Moreover, the MR Egger Q value was 8.141 with a P value of 0.701, while the IVW Q value was also 8.141 with a P value of 0.774, indicating no significant heterogeneity. Additionally, the MR Egger intercept was 0.0004, which was close to zero with a P value of 0.988, suggesting no pleiotropy. However, the study did find a causal relationship between several other factors such as testosterone, high-density lipoprotein, sex hormone-binding globulin, body mass index, waist-hip ratio, apolipoprotein A-I, number of children, diabetes illnesses of mother, father and siblings, hemoglobin A1c, fasting insulin, fasting blood glucose, years of schooling, and GDM based on the IVW method.

Conclusion

We observed no association between genetically predicted PCOS and the risk of GDM, implying that PCOS itself does not confer an increased susceptibility to GDM. The presence of other PCOS-related factors such as testosterone, high-density lipoprotein, and sex hormone-binding globulin may elucidate the link between PCOS and GDM. Based on these findings, efforts aimed at preventing GDM in individuals with PCOS should prioritize those exhibiting high-risk features rather than encompassing all women with PCOS.

Autoimmune diseases and risk of gestational diabetes mellitus: a Mendelian randomization study

AIMS

Observational studies have reported that autoimmune diseases are associated with gestational diabetes mellitus (GDM), but the causality is unknown. The study aimed to evaluate the potential causal effect of autoimmune diseases on GDM.

METHODS

A two-sample Mendelian randomization (MR) study was designed using the summary statistics of GDM (123,579 individuals) and three common autoimmune diseases, including inflammatory bowel disease (IBD, 59,957 individuals), rheumatoid arthritis (RA, 80,799 individuals) and systemic lupus erythematosus (SLE, 14,267 individuals), from the genome-wide association study (GWAS). The fixed-effects inverse variance weighted (IVW) was used to deduce the causal association between autoimmune diseases and GDM, and sensitivity analyses were further performed.

RESULTS

The inverse variance weighting (IVW) method showed that RA and SLE increased the risk of GDM (RA: OR = 1.076, 95%CI = 1.033-1.122, P = 4.649E-04; SLE: OR = 1.025, 95%CI = 1.001-1.049, P = 0.044). But there were no any associations of IBD with GDM (P > 0.05). No significant horizontal pleiotropy was found by MR Egger regression (IBD: P for intercept = 0.905; RA: P for intercept = 0.103; SLE = P for intercept = 0.608).

CONCLUSION

This two-sample MR study found that both SLE and RA are positively associated with the risk of GDM. Our findings provide help for the future prevention and treatment of GDM to reduce associated maternal and fetal complications. However, more research is needed to obviate the role of the GC and the HCQ to ensure this relationship is causal.

MicroRNA-322 overexpression reduces neural tube defects in diabetic pregnancies

BACKGROUND

Hyperglycemia from pregestational diabetes mellitus induces neural tube defects in the developing fetus. Folate supplementation is the only effective way to prevent neural tube defects; however, some cases of neural tube defects are resistant to folate. Excess folate has been linked to higher maternal cancer risk and infant allergy. Therefore, additional interventions are needed. Understanding the mechanisms underlying maternal diabetes mellitus-induced neural tube defects can identify potential targets for preventing such defects. Despite not yet being in clinical use, growing evidence suggests that microRNAs are important intermediates in embryonic development and can serve as both biomarkers and drug targets for disease intervention. Our previous studies showed that maternal diabetes mellitus in vivo activates the inositol-requiring transmembrane kinase/endoribonuclease 1α (IRE1α) in the developing embryo and that a high glucose condition in vitro reduces microRNA-322 (miR-322) levels. IRE1α is an RNA endonuclease; however, it is unknown whether IRE1α targets and degrades miR-322 specifically or whether miR-322 degradation leads to neural tube defects via apoptosis. We hypothesize that IRE1α can inhibit miR-322 in maternal diabetes mellitus-induced neural tube defects and that restoring miR-322 expression in developing neuroepithelium ameliorates neural tube defects.

OBJECTIVE

This study aimed to identify potential targets for preventing maternal diabetes mellitus-induced neural tube defects and to investigate the roles and relationship of a microRNA and an RNA endonuclease in mouse embryos exposed to maternal diabetes mellitus.

STUDY DESIGN

To determine whether miR-322 reduction is necessary for neural tube defect formation in pregnancies complicated by diabetes mellitus, male mice carrying a transgene expressing miR-322 were mated with nondiabetic or diabetic wide-type female mice to generate embryos with or without miR-322 overexpression. At embryonic day 8.5 when the neural tube is not yet closed, embryos were harvested for the assessment of 3 miR-322 transcripts (primary, precursor, and mature miR-322), tumor necrosis factor receptor-associated factor 3 (TRAF3), and neuroepithelium cell survival. Neural tube defect incidences were determined in embryonic day 10.5 embryos when the neural tube should be closed if there is no neural tube defect formation. To identify which miR-322 transcript is affected by maternal diabetes mellitus and high glucose conditions, 3 miR-322 transcripts were assessed in embryos from dams with or without diabetes mellitus and in C17.2 mouse neural stem cells treated with different concentrations of glucose and at different time points. To determine whether the endonuclease IRE1α targets miR-322, small interfering RNA knockdown of IRE1α or overexpression of inositol-requiring transmembrane kinase/endoribonuclease 1α by DNA plasmid transfection was used to determine the effect of IRE1α deficiency or overexpression on miR-322 expression. RNA immunoprecipitation was performed to reveal the direct targets of inositol-requiring transmembrane kinase/endoribonuclease 1α.

RESULTS

Maternal diabetes mellitus suppressed miR-322 expression in the developing neuroepithelium. Restoring miR-322 expression in the neuroepithelium blocked maternal diabetes mellitus-induced caspase-3 and caspase-8 cleavage and cell apoptosis, leading to a neural tube defect reduction. Reversal of maternal diabetes mellitus-inhibited miR-322 via transgenic overexpression prevented TRAF3 up-regulation in embryos exposed to maternal diabetes mellitus. Activated IRE1α acted as an endonuclease and degraded precursor miR-322, resulting in mature miR-322 reduction.

CONCLUSION

This study supports the crucial role of the IRE1α-microRNA-TRAF3 circuit in the induction of neuroepithelial cell apoptosis and neural tube defect formation in pregnancies complicated by diabetes mellitus and identifies IRE1α and miR-322 as potential targets for preventing maternal diabetes mellitus-induced neural tube defects.

Maternal obesity induced metabolic disorders in offspring and myeloid reprogramming by epigenetic regulation

Maternal obesity and gestational diabetes are associated with childhood obesity and increased cardiovascular risk. In this review, we will discuss and summarize extensive clinical and experimental studies that metabolically imbalanced environment exposure in early life plays a critical role in influencing later susceptibility to chronic inflammatory diseases and metabolic syndrome. The effect of maternal obesity and metabolic disorders, including gestational diabetes cause Large-for-gestational-age (LGA) children to link future development of adverse health issues such as obesity, atherosclerosis, hypertension, and non-alcoholic fatty liver disease by immune reprogramming to adverse micro-environment. This review also addresses intrauterine environment-driven myeloid reprogramming by epigenetic regulations and the epigenetic markers as an underlying mechanism. This will facilitate future investigations regarding maternal-to-fetal immune regulation and the epigenetic mechanisms of obesity and cardiovascular diseases.

Gestational diabetes in mice induces hematopoietic memory that affects the long-term health of the offspring

Gestational diabetes is a common medical complication of pregnancy that is associated with adverse perinatal outcomes and an increased risk of metabolic diseases and atherosclerosis in adult offspring. The mechanisms responsible for this delayed pathological transmission remain unknown. In mouse models, we found that the development of atherosclerosis in adult offspring born to diabetic pregnancy can be in part linked to hematopoietic alterations. Although they do not show any gross metabolic disruptions, the adult offspring maintain hematopoietic features associated with diabetes, indicating the acquisition of a lasting diabetic hematopoietic memory. We show that the induction of this hematopoietic memory during gestation relies on the activity of the advanced glycation end product receptor (AGER) and the nucleotide binding and oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, which lead to increased placental inflammation. In adult offspring, we find that this memory is associated with DNA methyltransferase 1 (DNMT1) upregulation and epigenetic changes in hematopoietic progenitors. Together, our results demonstrate that the hematopoietic system can acquire a lasting memory of gestational diabetes and that this memory constitutes a pathway connecting gestational health to adult pathologies.

Placenta-derived exosomes exacerbate beta cell dysfunction in gestational diabetes mellitus through delivery of miR-320b

Recent studies have shown placenta-derived exosome (pdE) acts as an important mediator of organ-to-organ interplay regulating maternal metabolic alterations, however, the function and mechanisms of placental exosomes on pancreatic β-cell maladaptation in gestational diabetes mellitus (GDM) remain unclear. The purpose of this investigation was to ascertain how placental exosomes affected the β-cell dysfunction associated with the onset of GDM. Exosomes were isolated from chorionic villi explants of pregnant mice and humans with normal glucose tolerance (NGT) and GDM. The effects of pdE from GDM on glucose tolerance in vivo and islets function in vitro were determined. Isolated islets from mice fed on the chow diet displayed an increase in apoptosis and observed their glucose-stimulated insulin secretion (GSIS) greatly diminished by PdE from GDM mice. Mice that accepted PdE from mice with GDM possessed glucose intolerance.Based on miRNA microarray assay and bioinformatics analysis from human placental exosomes, we identified miR-320b selectively enriched in PdE secreted in GDM compared with NGT. Importantly, the level of placental miR-320b was positively correlated with the 1h-glucose and 2-h glucose of a 75 g oral glucose tolerance test (OGTT) during human pregnancies. Furthermore, miR-320 overexpression attributed to impaired insulin secretion and increased apoptosis in MIN6 cells and islets obtained from mice with normal insulin sensitivity. This study firstly proposed that altered miRNAs in pdE contribute to defective adaptation of β cells during pregnancy, which expands the knowledge of GDM pathogenesis. Exosomes from the placenta may be an emerging therapeutic target for GDM.

Assessment of potential risk factors associated with gestational diabetes mellitus: evidence from a Mendelian randomization study

Background

Previous research on the association between risk factors and gestational diabetes mellitus (GDM) primarily comprises observational studies with inconclusive results. The objective of this study is to investigate the causal relationship between 108 traits and GDM by employing a two-sample Mendelian randomization (MR) analysis to identify potential risk factors of GDM.

Methods

We conducted MR analyses to explore the relationships between traits and GDM. The genome-wide association studies (GWAS) for traits were primarily based on data from the UK Biobank (UKBB), while the GWAS for GDM utilized data from FinnGen. We employed a false discovery rate (FDR) of 5% to account for multiple comparisons.

Results

The inverse-variance weighted (IVW) method indicated that the genetically predicted 24 risk factors were significantly associated with GDM, such as "Forced expiratory volume in 1-second (FEV1)" (OR=0.76; 95% CI: 0.63, 0.92), "Forced vital capacity (FVC)" (OR=0.74; 95% CI: 0.64, 0.87), "Usual walking pace" (OR=0.19; 95% CI: 0.09, 0.39), "Sex hormone-binding globulin (SHBG)" (OR=0.86; 95% CI: 0.78, 0.94). The sensitivity analyses with MR-Egger and weighted median methods indicated consistent results for most of the trats.

Conclusion

Our study has uncovered a significant causal relationship between 24 risk factors and GDM. These results offer a new theoretical foundation for preventing or mitigating the risks associated with GDM.

Methylation of serotonin regulating genes in cord blood cells: association with maternal metabolic parameters and correlation with methylation in peripheral blood cells during childhood and adolescence

BACKGROUND

Serotonin (5-hydroxytryptamine, 5-HT) signaling is involved in neurodevelopment, mood regulation, energy metabolism, and other physiological processes. DNA methylation plays a significant role in modulating the expression of genes responsible for maintaining 5-HT balance, such as 5-HT transporter (SLC6A4), monoamine oxidase A (MAOA), and 5-HT receptor type 2A (HTR2A). Maternal metabolic health can influence long-term outcomes in offspring, with DNA methylation mediating these effects. We investigated associations between maternal metabolic parameters-pre-pregnancy body mass index (pBMI), gestational weight gain (GWG), and glucose tolerance status (GTS), i.e., gestational diabetes mellitus (GDM) versus normal glucose tolerance (NGT)-and cord blood methylation of SLC6A4, MAOA, and HTR2A in participants from our PlaNS birth cohort. CpG sites (15, 9, and 2 in each gene, respectively) were selected based on literature and in silico data. Methylation levels were quantified by bisulfite pyrosequencing. We also examined the stability of methylation patterns in these genes in circulating blood cells from birth to adolescence using longitudinal DNA methylation data from the ARIES database.

RESULTS

None of the 203 PlaNS mothers included in this study had preexisting diabetes, 99 were diagnosed with GDM, and 104 had NGT; all neonates were born at full term by planned Cesarean section. Methylation at most CpG sites differed between male and female newborns. SLC6A4 methylation correlated inversely with maternal pBMI and GWG, while methylation at HTR2A site -1665 correlated positively with GWG. None of the maternal metabolic parameters statistically associated with MAOA methylation. DNA methylation data in cord blood and peripheral blood at ages 7 and 15 years were available for 808 participants from the ARIES database; 4 CpG sites (2 in SLC6A4 and 2 in HTR2A) overlapped between the PlaNS and ARIES cohorts. A positive correlation between methylation levels in cord blood and peripheral blood at 7 and 15 years of age was observed for both SLC6A4 and HTR2A CpG sites.

CONCLUSIONS

Methylation of 5-HT regulating genes in cord blood cells is influenced by neonatal sex, with maternal metabolism playing an additional role. Inter-individual variations present in circulating blood cells at birth are still pronounced in childhood and adolescence.

Correlation between TCF7L2 and CAPN10 gene polymorphisms and gestational diabetes mellitus in different geographical regions: a meta-analysis

BACKGROUND

The association between TCF7L2 and CAPN10 gene polymorphisms and gestational diabetes mellitus (GDM) has been explored in diverse populations across different geographical regions. Yet, most of these studies have been confined to a limited number of loci, resulting in inconsistent findings. In this study, we conducted a comprehensive review of published literature to identify studies examining the relationship between TCF7L2 and CAPN10 gene polymorphisms and the incidence of GDM in various populations. We specifically focused on five loci that were extensively reported in a large number of publications and performed a meta-analysis.

METHODS

We prioritized the selection of SNPs with well-documented correlations established in existing literature on GDM. We searched eight Chinese and English databases: Cochrane, Elton B. Stephens. Company (EBSCO), Embase, Scopus, Web of Science, China National Knowledge Infrastructure (CNKI), Wanfang, and China Science and Technology Journal Database and retrieved all relevant articles published between the inception of the database and July 2022. The Newcastle Ottawa Scale (NOS) was used to evaluate the selected articles, and the odds ratio (OR) was used as the combined effect size index to determine the association between genotypes, alleles, and GDM using different genetic models. Heterogeneity between the studies was quantified and the I2 value calculated. Due to large heterogeneities between different ethnic groups, subgroup analysis was used to explore the correlation between genetic polymorphisms and the incidence of GDM in the different populations. The stability of the results was assessed using sensitivity analysis. Begg's and Egger's tests were used to assess publication bias.

RESULTS

A total of 39 articles reporting data on 8,795 cases and 16,290 controls were included in the analysis. The frequency of the rs7901695 genotype was statistically significant between cases and controls in the European population (OR = 0.72, 95% CI: 0.65-0.86) and the American population (OR = 0.61, 95% CI: 0.48-0.77). The frequencies of rs12255372, rs7901695, rs290487, and rs2975760 alleles were also considerably different between the cases and controls in the populations analyzed.

CONCLUSIONS

rs7903146, rs12255372, rs7901695, rs290487, and rs2975760 were associated with the incidence of GDM in different populations.

Altered expression of long noncoding RNA MEG3 in the offspring of gestational diabetes mellitus induces impaired glucose tolerance in adulthood

AIM

Gestational diabetes mellitus (GDM) affects a significant number of women worldwide and has been associated with lifelong health consequences for their offspring, including increased susceptibility to obesity, insulin resistance, and type II diabetes. Recent studies have suggested that aberrant expression of the long non-coding RNA Meg3 in the liver may contribute to impaired glucose metabolism in individuals. In this study, we aimed to investigate whether intrauterine exposure to hyperglycemia affects glucose intolerance in puberty by mediating the overexpression of LncMeg3 in the liver.

METHODS

To test our hypothesis, we established an animal model of intrauterine hyperglycemia to mimic GDM. The progeny was observed for phenotypic changes, and intraperitoneal glucose tolerance tests, insulin tolerance tests, and pyruvate tolerance tests were conducted to assess glucose and insulin tolerance. We also measured LncMeg3 expression in the liver using real-time quantitative PCR and examined differential methylation areas (DMRs) in the Meg3 gene using pyrophosphoric sequencing. To investigate the role of LncMeg3 in glucose tolerance, we conducted Meg3 intervention by vein tail and analyzed the changes in the phenotype and transcriptome of the progeny using bioinformatics analysis.

RESULTS

We found that intrauterine exposure to hyperglycemia led to impaired glucose and insulin tolerance in the progeny, with a tendency toward increased fasting blood glucose in fat offspring at 16 weeks (P = 0.0004). LncMeg3 expression was significantly upregulated (P = 0.0061), DNMT3B expression downregulated (P = 0.0226), and DNMT3A (P = 0.0026), TET2 (P = 0.0180) expression upregulated in the liver. Pyrophosphoric sequencing showed hypomethylation in Meg3-DMRs (P = 0.0005). Meg3 intervention by vein tail led to a decrease in the percentage of obese and emaciated offspring (emaciation: 44% vs. 23%; obesity: 25% vs. 15%) and attenuated glucose intolerance. Bioinformatics analysis revealed significant differences in the transcriptome of the progeny, particularly in circadian rhythm and PPAR signaling pathways.

CONCLUSION

In conclusion, our study suggests that hypomethylation of Meg3-DMRs increases the expression of the imprinted gene Meg3 in the liver of males, which is associated with impaired glucose tolerance in GDM-F1. MEG3 interference may attenuate glucose intolerance, which may be related to transcriptional changes. Our findings provide new insights into the mechanisms underlying the long-term effects of intrauterine hyperglycemia on progeny health and highlight the potential of Meg3 as an intervention target for glucose intolerance.

METTL14-mediated lncRNA XIST silencing alleviates GDM progression by facilitating trophoblast cell proliferation and migration via the miR-497-5p/FOXO1 axis

Gestational diabetes mellitus (GDM), a prevalent complication during the gestation period, has been linked to impaired proliferation and migration of trophoblasts causing placental maldevelopment. We previously found that lncRNA X-inactive specific transcript (XIST) played an essential role in GDM progression. Here, we investigated the precise biological functions as well as the upstream and downstream regulatory mechanisms of XIST in GDM. We found that XIST and forkhead box O1 (FOXO1) were conspicuously upregulated and miR-497-5p and methyltransferase-like 14 (METTL14) were downregulated in the placentas of GDM patients. XIST silencing facilitated proliferation and migration and inhibited cell apoptosis and cell cycle arrest in HG-cultured HTR8/SVneo cells. METTL14 inhibited XIST expression through m6A methylation modification. XIST overexpression abrogated the positive effect of METTL14 overexpression on HG-cultured HTR8/SVneo cell progression. MiR-497-5p and FOXO1 are downstream regulatory genes of XIST in HTR8/SVneo cells. Reverse experiments illustrated that XIST mediated HTR8/SVneo cell functions by regulating the miR-497-5p/FOXO1 axis. Additionally, XIST silencing augmented glucose tolerance and alleviated fetal detrimental changes in GDM rats. To conclude, METTL14-mediated XIST silencing facilitated proliferation and migration and inhibited cell apoptosis and cell cycle arrest in HG-cultured HTR8/SVneo cells via the miR-497-5p/FOXO1 axis, thereby alleviating GDM progression in rats.

ABHD5-CPT1B: An Important Way of Regulating Placental Lipid Metabolism in Gestational Diabetes Mellitus

BACKGROUND AND AIM

Gestational diabetes mellitus (GDM) is one of the most common metabolic disorders in pregnancy, and a novel association of maternal lipid profile has been suggested to play an important role. However, the molecular mechanism is not clear.

METHODS

Bio-analyzed combined with placental metabonomics and single-cell RNA-sequencing (scRNA-seq) successfully identified a potentially important molecule: α-β hydrolase domain-containing protein 5 (ABHD5). The syncytiotrophoblast (SCT) cell model was adopted as a fusion of BeWo cells in response to forskolin. On this basis, the high glucose-stimulated cell experiment was carried out. 15 women with GDM and 15 normal pregnant women were recruited for validation experiments.

RESULTS

ABHD5 was mainly expressed in the trophoblast cells, especially in SCT cells, and significantly decreased in the GDM placenta. After stimulation by high glucose, the expression of ABHD5 was downregulated in a time-dependent manner in BeWo cells treated with forskolin. At the same time, lipid droplets (LDs) were increased in the SCT. LD storage was also increased in the SCT with siABHD5, while it was significantly reduced in SCT cells with high ABHD5 expression. However, this effect could be attenuated by downregulated carnitine palmitoyltransferase 1B (CPT1B).

CONCLUSIONS

ABHD5-CPT1B is confirmed as an important regulator of placental lipid metabolism.

Role of CircCHD2 in the pathogenesis of gestational diabetes mellitus by regulating autophagy via miR-33b-3p/ULK1 axis

Gestational diabetes mellitus (GDM) is a common pregnancy complication with a high incidence in women; however, its pathophysiology remains unknown. Our previous study suggested that the circCHD2/miR-33b-3p/ULK1 axis may be involved in GDM pathogenesis. However, the mechanism through which circCHD2 regulates GDM development requires further investigation. We found that high-glucose (HG, 25 mmol/L) significantly induced the expression of circCHD2, increased autophagy and apoptosis, and decreased cell viability in human placental trophoblast HTR-8/SVneo cells. In contrast, the downregulation of circCHD2 significantly attenuated the effects of HG on HTR-8/SVneo cells. MiR-33b-3p downregulated in the placenta of GDM patients was reduced by HG and detected as a target of circCHD2 using bioinformatics analysis, a dual-luciferase reporter assay, and qRT-PCR assay. Further studies showed that the inhibition of miR-33b-3p significantly blocked the effects of circCHD2 downregulation on cell viability, apoptosis, and autophagy in HG-treated HTR-8/SVneo cells. ULK1 is a target of miR-33b-3p, based on bioinformatics analysis, a dual-luciferase reporter assay, qRT-PCR assay, and Western blot analysis. Compared to miR-33b-3p, ULK1 is upregulated in the placenta of GDM patients. ULK1 overexpression notably blocked the effects of miR-33b-3p mimics on cell viability, apoptosis, and autophagy in HG-treated HTR-8/SVneo cells. These findings suggested that circCHD2 acts as an autophagy promoter via the miR-33b-3p/ULK1 axis to induce apoptosis in HTR-8/SVneo cells, suggesting that circCHD2 is a potential diagnostic and therapeutic target for GDM.

Methylation analysis by targeted bisulfite sequencing in large for gestational age (LGA) newborns: the LARGAN cohort

BACKGROUND

In 1990, David Barker proposed that prenatal nutrition is directly linked to adult cardiovascular disease. Since then, the relationship between adult cardiovascular risk, metabolic syndrome and birth weight has been widely documented. Here, we used the TruSeq Methyl Capture EPIC platform to compare the methylation patterns in cord blood from large for gestational age (LGA) vs adequate for gestational age (AGA) newborns from the LARGAN cohort.

RESULTS

We found 1672 differentially methylated CpGs (DMCs) with a nominal p < 0.05 and 48 differentially methylated regions (DMRs) with a corrected p < 0.05 between the LGA and AGA groups. A systems biology approach identified several biological processes significantly enriched with genes in association with DMCs with FDR < 0.05, including regulation of transcription, regulation of epinephrine secretion, norepinephrine biosynthesis, receptor transactivation, forebrain regionalization and several terms related to kidney and cardiovascular development. Gene ontology analysis of the genes in association with the 48 DMRs identified several significantly enriched biological processes related to kidney development, including mesonephric duct development and nephron tubule development. Furthermore, our dataset identified several DNA methylation markers enriched in gene networks involved in biological pathways and rare diseases of the cardiovascular system, kidneys, and metabolism.

CONCLUSIONS

Our study identified several DMCs/DMRs in association with fetal overgrowth. The use of cord blood as a material for the identification of DNA methylation biomarkers gives us the possibility to perform follow-up studies on the same patients as they grow. These studies will not only help us understand how the methylome responds to continuum postnatal growth but also link early alterations of the DNA methylome with later clinical markers of growth and metabolic fitness.

Genetic variants of ERBB4 gene and risk of gestational diabetes mellitus: a susceptibility and diagnostic nomogram study

Introduction

Gestational diabetes (GDM) is one of the common complications of female pregnancy, which seriously affects the health of mothers and their offspring. So far, the etiology has not been fully clarified.

Methods

A case-control study was conducted to clarify the relationship between Erb-b2 receptor tyrosine kinase 4 (ERBB4) functional tag genetic variants (rs1595064, rs1595065, rs1595066 and rs6719645) and the risk of GDM. Associations between variants and GDM risk were evaluated with the odds ratios (ORs) and their corresponding 95% confidence intervals (CIs). Subsequently, the false-positive reporting probability (FPRP), multi-factor dimension reduction (MDR) and bioinformatics analysis were adopted to confirm the significant associations. A nomogram model was constructed to predict the risk of GDM.

Results

Association analysis demonstrated that rs1595066 TT genotype performed a protective effect on GDM risk among all subjects (TT vs. CC: adjusted OR = 0.60, 95% CI = 0.38 - 0.94, P = 0.026; TT vs. CC/CT: adjusted OR = 0.61, 95% CI = 0.40 - 0.95, P = 0.027). Meanwhile, stratified analysis showed that rs1595066 TT can also reduce the GDM risk in age > 30.09 years old, pre-pregnancy BMI > 22.23 Kg/m2, SBP ≤ 110.08 mmHg, etc subgroups. Interactions between rs1595066 and DBP (P interaction = 0.01), FPG (P interaction < 0.001) and HbA1c (P interaction < 0.001) were detected. The FPRP analysis confirmed that association between rs1595066 and GDM risk in subjects of FPG < 4.79 mmol/L (P = 0.199) is true. The MDR analysis showed that rs1595066 was the best single locus model while the 4-loci model was the best multiple factors model to predict GDM risk. Functional prediction revealed that rs1595066 may disturb the stability of miRNA-mRNA binding. The predictive nomogram model has a well consistence and acceptable discriminative ability with a diagnosed AUC of 0.813.

Discussion

ERBB4 variants can change an individual's susceptibility to GDM via the interaction of gene-gene, gene-environment and changes in the regulatory effects of miRNAs on ERBB4 expression.

Global DNA methylation and miR-126-3p expression in Mexican women with gestational diabetes mellitus: a pilot study

BACKGROUND

Gestational diabetes mellitus (GDM), a type of diabetes that occurs for the first time during pregnancy, may predispose the development of chronic degenerative diseases and metabolic alterations in mother and offspring. DNA methylation and microRNA (miRNA) expression are regulatory mechanisms of gene expression that may contribute to the pathogenesis of GDM. Therefore, we determined global DNA methylation and miR-126-3p expression levels in 8 and 7 Mexican women with and without GDM, respectively.

METHODS AND RESULTS

Global DNA methylation was assessed by measuring the percentage of 5-methylcytosine (5-mC) in placenta, umbilical cord, and plasma DNA samples, whereas miR-126-3p expression was quantified by real-time PCR using the 2-ΔCt method of the corresponding RNA samples. A significant increase in the percentage of 5-mC was detected in placenta samples from GDM patients compared to healthy women, while plasma samples showed a significant decrease. Conversely, miR-126-3p expression levels were significantly higher in plasma from the GDM group, while placenta and umbilical cord samples showed no significant differences across experimental groups. Furthermore, DNA methylation correlated significantly with glucose levels in placenta and plasma. Likewise, miR-126-3p expression correlated significantly with plasma glucose, in addition to maternal body mass index (BMI at first trimester).

CONCLUSION

The results indicate that GDM is associated with alterations in global DNA methylation levels and miR-126-3p expression in placenta and/or plasma, providing insights into future novel approaches to diagnose and/or prevent this pathology.

Impact of vitamin D resistance genes on vitamin D deficiency during pregnancy among the South Indian population

Increasing evidence suggests that vitamin D (Vit-D) could be pivotal in maintaining normal glucose homeostasis. Low levels of Vit-D in early pregnancy are associated with a higher risk of gestational diabetes mellitus (GDM). Though several reports have highlighted the prevalence of vit-D deficiency among pregnant women, its underlying cause has not yet been fully elucidated. In this connection, a few studies have found the development of resistance to Vit-D, including the levels of Vitamin D receptor (VDR) and transcription regulators that modify VDR action, as well as the bioavailability of Vit-D. We aimed to determine the levels of Vit-D resistance genes such as 25-HydroxyVit-D-24-hydroxylase (CYP24A1), VDR repressor genes (SNAIL and SMRT) and their association between Vit-D concentrations in early pregnancy, and the risk of gestational diabetes mellitus (GDM). A prospective observational study was conducted on healthy pregnant women (NGDM; n = 50) and GDM (n = 50) attending routine antenatal care at SRM Medical College Hospital, Chennai, recruited at 12 weeks of gestation. We found that the serum levels of Vit-D were low in GDM subjects and negatively correlated with the fasting glucose levels. Further, increased expressions of Vit-D resistance genes such as CYP24A1, SNAIL, and SMRT were observed in GDM subjects and negatively correlated with the serum levels of Vit-D. Furthermore, we have validated the data using the trophoblast cell line, BeWo, exposed to calcitriol under a hyperglycemic environment. Our finding showed that increased expression of Vit-D resistance genes in pregnancy may be associated with a greater risk of adverse pregnancy outcomes, including GDM.

Association of HHEX and SLC30A8 Gene Polymorphisms with Gestational Diabetes Mellitus Susceptibility: A Meta-analysis

Genetics plays a role in the development of gestational diabetes mellitus (GDM), which poses serious risks to pregnant women and their children. Several studies have demonstrated a link between GDM susceptibility and rs13266634 C/T polymorphism in SLC30A8 gene and rs1111875 C/T and rs5015480 C/T, which are located near the linkage disequilibrium block containing the IDE, HHEX, and KIF11 genes. However, the results are conflicting. Therefore, we aimed to investigate the association between susceptibility to GDM and HHEX and SLC30A8 gene polymorphisms. PubMed, Web of Science, EBSCO, CNKI, Wanfang Data, VIP, and SCOPUS were used to search for research articles. The quality of the selected literature was evaluated using the Newcastle-Ottawa scale. A meta-analysis was performed using Stata 15.1. Allelic, dominant, recessive, homozygote, and heterozygote models were used for the analysis. Nine articles with 15 studies were included. (1) Four studies about HHEX rs1111875 showed that the C allele was associated with the susceptibility to GDM; (2) three studies on HHEX rs5015480 indicated that the C allele in rs5015480 was significantly associated with GDM; (3) eight studies about SLC30A8 rs13266634 showed that the C allele was significantly associated with the susceptibility to GDM; and (4) a subgroup analysis showed that the rs5015480 polymorphism in HHEX and rs13266634 polymorphism in SLC30A8 gene were associated with GDM susceptibility in Asians. The meta-analysis provided evidence that the C allele in rs1111875 and rs5015480 in HHEX and rs13266634 in SLC30A8 can increase the risk of GDM.PROSPERO registration number CRD42022342280.

GCKR and ADIPOQ gene polymorphisms in women with gestational diabetes mellitus

AIMS

To investigate the associations of GCKR and ADIPOQ variants with the risk of gestational diabetes mellitus (GDM) in Chinese women.

METHODS

GCKR rs1260326, ADIPOQ rs266729, and rs1501299 were selected and genotyped in 519 GDM patients and 498 controls. Candidate SNPs were genotyped using multiplex polymerase chain reaction (PCR) combined with next-generation sequencing methods, and the association of these SNPs with GDM was analyzed.

RESULTS

We found that GCKR rs1260326 was significantly associated with an increased risk of GDM in the allele model, the codominant model (CC vs. TT), the dominant model, the recessive model, and the genotypic model distributions (p = 0.0029, p = 0.0022, p = 0.0402, p = 0.0038, and p = 0.0028, respectively). The rs1260326 polymorphism was shown to be associated with 1 h-OGTT level and gravidity in GDM patients (CC vs. TT: p = 0.0475 and p = 0.0220, respectively). Diastolic blood pressure (DBP) was significantly higher in the GDM patients with the rs266729 GG genotype compared to those with the CC or CG genotype (p = 0.0444 and p = 0.0339, respectively). The DBP of the GDM patients with the rs1501299 GT genotype was lower than that of those with the GG genotype (p = 0.0197). There was a weak linkage disequilibrium value between the GCKR and ADIPOQ SNPs.

CONCLUSIONS

The genes GCKR and ADIPOQ may be involved in the pathophysiology of GDM.

Association between VDR genetic polymorphisms and risk of gestational diabetes mellitus in the Chinese population

BACKGROUND AND AIMS

Abnormal metabolism of vitamin D was the primary mechanism in many pregnancy diseases. Our study was the first to examine the hypothesis that VDR gene polymorphisms contribute to the risk of gestational diabetes mellitus (GDM) in the Chinese population at high altitudes.

MATERIALS AND METHODS

One hundred and eighteen women with GDM and 104 women with normal glucose tolerance (NGT) were included in this study using a case-control design. Four single nucleotide polymorphisms (g.47879112G > A, g.47846052C > T, g.47844974A > G, and g.47845054C > A) of mother and fetus were genotyped.

RESULTS

Maternal and fetal frequency of the A allele of g.47879112G > A was significantly increased in women with GDM than in those with NGT (p < .05). A correlation between the AA homozygous genotype of g.47879112G > A and GDM was noted. Compared with non-carriers, A allele carriers showed higher fasting plasma insulin and two-hour post-challenge plasma glucose (2h-PPG), and lower levels of vitamin D. Furthermore, both maternal and fetal 4-marker haplotype ACCG were found to be significantly associated with GDM (p < .05).

CONCLUSIONS

Association and haplotype analysis indicated that the A allele of g.47879112G > A could be a risk factor for GDM development in the Chinese population at high altitudes. Additionally, the VDR gene polymorphism of the fetus and mother may have a synergistic effect. The VDR polymorphism is associated with an increased risk of GDM and may be useful for predicting the development of the disease.

Analysis of global DNA methylation and epigenetic modifiers (DNMTs and HDACs) in human foetal endothelium exposed to gestational and type 2 diabetes

Foetuses exposed to maternal gestational diabetes (GDM) and type 2 diabetes (T2D) have an increased risk of adverse perinatal outcomes. Epigenetic mechanisms, including DNA methylation and histone modifications, may act as mediators of persistent metabolic memory in endothelial cells (ECs) exposed to hyperglycaemia, even after glucose normalization. Therefore, we investigated alterations in global DNA methylation and epigenetic modifier expression (DNMT1, DNMT3a, DNMT3b, HDAC1, and HDAC2) in human umbilical vein ECs (HUVECs) from the umbilical cords of mothers with GDM (n = 8) and T2D (n = 3) compared to that of healthy mothers (n = 6). Global DNA alteration was measured using a 5-methylation cytosine colorimetric assay, followed by quantitative real-time polymerase chain reaction to measure DNA methyltransferase and histone acetylase transcript expression. We revealed that DNA hypermethylation occurs in both GDM- and T2D-HUVECs compared to that in Control-HUVECs. Furthermore, there was a significant increase in HDAC2 mRNA levels in GDM-HUVECs and increase in DNMT3b mRNA levels in T2D-HUVECs. Overall, our results suggest that GDM and T2D are associated with global DNA hypermethylation in foetal endothelial cells under normoglycemic conditions and the aberrant mRNA expression of HDAC2 and DNMT3b could play a role in this dysregulation.