Associations of MTHFR Polymorphisms and Cytosine Modifications with Early-Gestational Diabetes Mellitus in Chinese Pregnant Women

Early-Gestational Diabetes Mellitus (Early-GDM) is a complex condition that may cause complications in infants of affected mothers. The aim of this case-control study was to analyze the effects of genetic-epigenetic interaction on Early-GDM and fetal development with respect to cytosine modifications (i.e., 5mC, 5-methylcytosines; and 5hmC, 5-hydroxymethylcytosines) and single nucleotide polymorphisms (SNPs) of MTHFR, a key gene involving cytosine modifications. Peripheral blood samples were collected from 92 women in their first or second trimester of pregnancy (Early-GDM, n = 14; Controls, n = 78). Global DNA 5mC and 5hmC were quantified by HPLC-MS/MS, and MTHFR SNPs (rs1801133 C > T and rs1801131 A > C) were determined by TaqMan-qPCR. Association analysis suggested that MTHFR rs1801133 TT genotype was a risk factor of Early-GDM (OR [odds ratio] = 4.00; 95% CI [confidence interval]: 1.24, 12.86; p = 0.02). The C allele of rs1801131 appeared to be a protective factor for the 2-h OGTT (oral glucose tolerance test) (OR = -0.79; 95% CI: -1.48, -0.10; p = 0.03). Patients with Early-GDM had higher global 5mC and lower global 5hmC. The reduction of global 5hmC and the TT genotype of rs1801133 were associated with higher level of the 1st-FBG (fasting blood glucose in the first trimester) (p < 0.05). Additionally, global 5mC showed a positive correlation with birth weight, body length and head circumference of newborns, while global 5hmC showed a negative correlation with birth weight. The current study implicated MTHFR SNPs and cytosine modifications in the development of Early-GDM and potential complications in their newborns.

Predictive value of first-trimester GPR120 levels in gestational diabetes mellitus

Background

Early diagnosis of gestational diabetes mellitus (GDM) reduces the risk of unfavorable perinatal and maternal consequences. Currently, there are no recognized biomarkers or clinical prediction models for use in clinical practice to diagnosing GDM during early pregnancy. The purpose of this research is to detect the serum G-protein coupled receptor 120 (GPR120) levels during early pregnancy and construct a model for predicting GDM.

Methods

This prospective cohort study was implemented at the Women's Hospital of Jiangnan University between November 2019 and November 2022. All clinical indicators were assessed at the Hospital Laboratory. GPR120 expression was measured in white blood cells through quantitative PCR. Thereafter, the least absolute shrinkage and selection operator (LASSO) regression analysis technique was employed for optimizing the selection of the variables, while the multivariate logistic regression technique was implemented for constructing the nomogram model to anticipate the risk of GDM. The calibration curve analysis, area under the receiver operating characteristic curve (AUC) analysis, and the decision curve analysis (DCA) were conducted for assessing the performance of the constructed nomogram.

Results

Herein, we included a total of 250 pregnant women (125 with GDM). The results showed that the GDM group showed significantly higher GPR120 expression levels in their first trimester compared to the normal pregnancy group (p < 0.05). LASSO and multivariate regression analyses were carried out to construct a GDM nomogram during the first trimester. The indicators used in the nomogram included fasting plasma glucose, total cholesterol, lipoproteins, and GPR120 levels. The nomogram exhibited good performance in the training (AUC 0.996, 95% confidence interval [CI] = 0.989-0.999) and validation sets (AUC=0.992) for predicting GDM. The Akaike Information Criterion of the nomogram was 37.961. The nomogram showed a cutoff value of 0.714 (sensitivity = 0.989; specificity = 0.977). The nomogram displayed good calibration and discrimination, while the DCA was conducted for validating the clinical applicability of the nomogram.

Conclusions

The patients in the GDM group showed a high GPR120 expression level during the first trimester. Therefore, GPR120 expression could be used as an effective biomarker for predicting the onset of GDM. The nomogram incorporating GPR120 levels in early pregnancy showed good predictive ability for the onset of GDM.

Enhanced recovery in patients with gestational diabetes mellitus and MTHFR 677 TT genotype after taking high-dose folic acid supplements during mid-late pregnancy: an open-label interventional study

Objective

To explore the relationship between folic acid supplementation and the recovery rate of gestational diabetes mellitus (GDM) in women with methylenetetrahydrofolate (MTHFR) 677 TT genotypes in mid-late pregnancy.

Methods

9, 096 pregnant women were recruited with their MTHFR gene genotyped. 5,111 women underwent a 75-g oral glucose tolerance test (OGTT) and 2,097 were confirmed with GDM. The association between MTHFR genotypes and GDM risk was estimated using logistic and log-binomial regression, with age and parity set as the covariates to control their confounding effects. Further assessment of GDM risk on glucose levels was done using the ANCOVA model. As an open-label intervention study, 53 GDM patients with TT genotype were prescribed 800μg/day of folic acid as the high-dose group, while 201 GDM patients were given 400μg/day as the standard-dose group at their 24-28 weeks of pregnancy. A rate ratio (RR) of GDM recovery was estimated at each available time point for both groups. The time-to-GDM persistence events were analyzed with the Kaplan-Meier method and Cox-regression model. The trend of glucose levels over time was estimated using the linear model.

Results

MTHFR 677 TT genotype has no significant association with the glucose levels and GDM risk, with an adjusted OR of 1.105 (95% CI 0.853, 1.431; p=0.452) and an adjusted PR of 1.050 (95% CI 0.906, 1.216; p=0.518) compared to the wildtype CC group. Patients in the high-dose group (n=38; 15 drop-outs; 40.69 days (95% CI 33.22, 48.15)) recovered from GDM approximately 27 days faster than those in the standard-dose group (n=133; 68 drop-outs; 68.09 days (95% CI 63.08, 73.11)). Concomitantly, the RR of GDM recovery rose and reached 1.247 (95% CI 1.026, 1.515) at 100 days of treatment with the standard-dose group as reference.

Conclusion

High-dose folic acid supplement intake in mid-late pregnancy is associated with faster GDM relief in patients with MTHFR 677 TT genotype compared to the standard dose, which would be served as a novel and low-cost alternative therapy for the treatment of GDM.

LncRNA XIST promotes insulin resistance in gestational diabetes mellitus via the microRNA-181b-5p/NDRG2 axis

Many studies have explored the role of lncRNA X inactivation-specific transcript (XIST) in diabetes. This study was designed to unravel the regulatory mechanism of XIST on animal models of gestational diabetes mellitus (GDM) progression via the microRNA (miR)-181b-5p/N-myc downstream-regulated gene 2 (NDRG2) axis. XIST, miR-181b-5p, and NDRG2 expression levels in GDM mice were detected. The GDM mice were subjected to gain- and loss-of-function assays to examine the change of glucose metabolism indices (fasting blood glucose (FBG), fasting insulin (FINS) and homeostasis model assessment of insulin resistance (HOMA-IR)), serum oxidative stress factors (glutathione (GSH), superoxide dismutase (SOD), and malondialdehyde (MDA)), serum inflammatory factors (interleukin-1 β (IL-1β), IL-6, and tumor necrosis factor α (TNF-α)), pathological changes of pancreatic tissues, and apoptotic cells in pancreatic islets in GDM mice. XIST and NDRG2 expression were elevated while miR-181b-5p expression was depleted in GDM mice. Down-regulated XIST or NDRG2 or up-regulated miR-181b-5p reduced the FBG level, HOMA-IR, and serum IL-1β, IL-6, and TNF-α, and MDA contents, elevated the FINS, GSH, and SOD level, mitigated pathological changes in pancreatic tissues, and decelerated apoptotic cells in pancreatic islets in GDM mice. Silenced XIST dampens insulin resistance in GDM mice via the modulation of the miR-181b-5p/NDRG2 axis.

Circular RNA HIPK3 facilitates ferroptosis in gestational diabetes mellitus by regulating glutathione peroxidase 4 DNA methylation

BACKGROUND

Gestational diabetes mellitus (GDM) is the most frequently occurring complication during pregnancy, with a high prevalence rate. Ferroptosis, a type of iron-dependent cell death, is closely associated with GDM nosogenesis. The present study aimed to examine the potential role and mechanism of circHIPK3 in GDM.

METHODS

Placental tissues, plasma samples, and HTR-8/SVneo cells were used. A receiver operating characteristic curve was used to analyze the diagnostic value of circHIPK3 in GDM. Actinomycin D and RnaseR were added to identify circHIPK3 characteristics. The expression of circHIPK3, miR-1278, and DNA methyltransferase 1 (DNMT1) was assessed using a quantitative reverse transcriptase-PCR. Cell counting kit-8 and terminal deoxynucleotidyl transferase dUTP nick end labeling assays and specific kits were employed to assess cell viability, apoptosis, reactive oxygen species (ROS), malondialdehyde, iron, glutathione, and glutathione peroxidase 4 (GPX4) levels.

RESULTS

The interaction between miR-1278 and circHIPK3 or DNMT1 was validated via luciferase reporter and RNA pull-down assays. circHIPK3 expression was found to be high in GDM placental tissues, plasma, and cells, with a high diagnostic value. In high glucose (HG)-induced HTR-8/SVneo cells, the inhibition of circHIPK3 provoked cell viability and mitigated cell apoptosis, ROS, and iron levels, but it was rescued through the downregulation of miR-1278. Mechanism experiments showed that circHIPK3 bound with miR-1278 targeting DNMT1 in GDM. The elevation in DNMT1 expression abolished the effects of miR-1278 overexpression on ferroptosis in HG-cultured HTR-8/SVneo cells.

CONCLUSIONS

Overall, circHIPK3 might facilitate ferroptosis via miR-1278/DNMT1 to regulate GPX4 DNA methylation in HG-cultured HTR-8/SVneo cells. CircHIPK3 could be a therapeutic agent for GDM treatment.

DNA methylation analysis reveals the effect of arsenic on gestational diabetes mellitus

BACKGROUND

Arsenic (As) exposure is one of the risk factors for gestational diabetes mellitus (GDM). This study aimed to explore the effect of As-exposure on DNA methylation in GDM and to establish a risk assessment model of GDM in As exposed pregnant women.

METHOD

We collected elbow vein blood of pregnant women before delivery to measure As concentration and DNA methylation data. Then compared the DNA methylation data and established a nomogram.

RESULT

We identified a total of 10 key differentially methylated CpGs (DMCs) and found 6 corresponding genes. Functions were enriched in Hippo signaling pathway, cell tight junction, prophetic acid metabolism, ketone body metabolic process, and antigen processing and presentation. A nomogram was established that can predict GDM risks (c-index = 0.595, s:p = 0.973).

CONCLUSION

We found 6 genes associated with GDM with high As exposure. The prediction of the nomograms has been proven to be effective.

[Association Between Apolipoprotein C-3 SstⅠ Polymorphism and Serum Lipids in Patients With Gestational Diabetes Mellitus]

Objective

To investigate the apolipoprotein C-3 (APOC3) gene Sst Ⅰ polymorphism and its relationship with changes in serum lipids in patients with gestational diabetes mellitus (GDM).

Methods

A total of 630 pregnant women with GDM and 1027 normal pregnant controls were covered in the study. The genotype and allele frequencies of APOC3 Sst Ⅰ polymorphism were analyzed by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP). Total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and glucose (Glu) were measured by enzymatic methods. Plasma insulin (INS) was measured by chemiluminescence. Apolipoproteins A 1 (apoA1) and B (apoB) levels were measured by turbidimetric immunoassay.

Results

The allele frequencies of S1 and S2 of the APOC3 polymorphism at the SstⅠ locus were 0.704 and 0.296 in the GDM group and 0.721 and 0.279 in the control group, respectively. There was no significant difference in genotype frequency and allele frequency of APOC3 Sst Ⅰ polymorphism between the GDM and the control groups ( P>0.05). In the GDM group, those with S2S2 and S1S2 genotypes had higher plasma HDL-C levels and lower atherogenic index (AI) values than those with S1S1 genotype did, with the differences being statistically significant (all P<0.05). GDM patients were then divided into obesity and non-obesity subgroups. Further subgroup analysis showed that the association of APOC3 genotype with changes in HDL-C levels was observed only in obese GDM patients, while the association of APOC3 genotype with changes in AI values was observed in both obese and nonobese patients. In addition, in obese GDM patients, those with S2S2 genotype had significantly higher plasma TG levels than those with S1S1 and S1S2 genotypes did ( P<0.05 and P<0.01, respectively). In non-obese GDM patients, those with S2S2 genotype had significantly lower apoB/apoA1 ratio than S2S2 carriers did ( P<0.05). No genotype-related effect on lipid and apolipoprotein variations was evident in the normal controls.

Conclusion

APOC3 Sst Ⅰ polymorphism in GDM patients is associated with HDL-C and TG levels as well as AI value and apoB/apoA1 ratio. The changes in lipid levels and apolipoprotein ratio showed BMI-dependent features. However, association between polymorphism at the locus and the development of GDM was not observed.

Associations between nutrients in one-carbon metabolism and fetal DNA methylation in pregnancies with or without gestational diabetes mellitus

BACKGROUND

Gestational diabetes mellitus (GDM), characterized by hyperglycemia that develops during pregnancy, increases the risk of fetal macrosomia, childhood obesity and cardiometabolic disorders later in life. This process has been attributed partly to DNA methylation modifications in growth and stress-related pathways. Nutrients involved with one-carbon metabolism (OCM), such as folate, choline, betaine, and vitamin B12, provide methyl groups for DNA methylation of these pathways. Therefore, this study aimed to determine whether maternal OCM nutrient intakes and levels modified fetal DNA methylation and in turn altered fetal growth patterns in pregnancies with and without GDM.

RESULTS

In this prospective study at a single academic institution from September 2016 to June 2019, we recruited 76 pregnant women with and without GDM at 25-33 weeks gestational age and assessed their OCM nutrient intake by diet recalls and measured maternal blood OCM nutrient levels. We also collected placenta and cord blood samples at delivery to examine fetal tissue DNA methylation of the genes that modify fetal growth and stress response such as insulin-like growth factor 2 (IGF2) and corticotropin-releasing hormone (CRH). We analyzed the association between maternal OCM nutrients and fetal DNA methylation using a generalized linear mixed model. Our results demonstrated that maternal choline intake was positively correlated with cord blood CRH methylation levels in both GDM and non-GDM pregnancies (r = 0.13, p = 0.007). Further, the downstream stress hormone cortisol regulated by CRH was inversely associated with maternal choline intake (r = - 0.36, p = 0.021). Higher maternal betaine intake and serum folate levels were associated with lower cord blood and placental IGF2 DNA methylation (r = - 0.13, p = 0.049 and r = - 0.065, p = 0.034, respectively) in both GDM and non-GDM pregnancies. Further, there was an inverse association between maternal betaine intake and birthweight of infants (r = - 0.28, p = 0.015).

CONCLUSIONS

In conclusion, we observed a complex interrelationship between maternal OCM nutrients and fetal DNA methylation levels regardless of GDM status, which may, epigenetically, program molecular pathways related to fetal growth and stress response.

Association of common variants of TCF7L2 and PCSK2 with gestational diabetes mellitus in West Bengal, India

The genetic etiology of gestational diabetes mellitus (GDM) was suggested to overlap with type-2 diabetes(T2D). Transcription factor 7-like 2 (TCF7L2) and Proprotein Convertase Subtilisin/Kexin type 2 (PCSK2) are T2D susceptibility genes of the insulin synthesis/processing pathway. We analyzed associations of TCF7L2 and PCSK2 variants with GDM risk and evaluated their potential impact on impaired insulin processing in an eastern Indian population. The study included 114 GDM (case) and 228 non-GDM pregnant women (control). rs7903146, rs4132670, rs12255372 of TCF7L2, and rs2269023 of PCSK2 were genotyped by PCR-RFLP, and genotype distributions were compared between case and control. Fasting serum proinsulin and C-peptide levels were measured by ELISA and the Proinsulin/C-peptide ratio was considered an indicator of proinsulin conversion. Significantly higher frequency of risk allele (T) of rs12255372 (p = 0.02, OR = 2.0, 95%CI = 1.11-3.64) and rs4132670 (p = 0.002, OR = 2.26, 95%CI = 1.32-3.87) of TCF7L2 was found in GDM cases than non-GDM controls; TT genotype was associated with significantly increased disease risk. In rs7903146 (TCF7L2) and rs2269023 (PCSK2), although the frequency of risk allele (T) was not significantly higher in cases than controls, an association of TT for both variants remained significant with higher GDM risk in the recessive model. Increased serum pro-insulin and proinsulin:c-peptide ratio was found in GDM than non-GDM women and the phenomenon showed significant association with careers of risk alleles for TCF7L2 variants. In conclusion, TCF7L2 and PCSK2 variants are related to GDM risk in the studied population and hence may serve as potential biomarkers for assessing the disease risk. TCF7L2 variants contribute to impaired insulin processing.

Ferroptosis and its potential role in gestational diabetes mellitus: updated evidence from pathogenesis to therapy

Background

Studies have demonstrated that high iron status is positively associated with gestational diabetes mellitus (GDM), implying that iron overload and ferroptosis play important roles in the development of GDM. The aim of this study was to explore effective therapeutic drugs from traditional Chinese medicine (TCM)formulas for the treatment of GDM based on ferroptosis.

Methods

In this study, the presence of ferroptosis in the placenta was verified through clinical and experimental data, and key genes were subsequently screened for association with ferroptosis in the development of GDM. The analysis was based on transcriptome sequencing of datasets combined with differentially expressed genes (DEGs) analysis and weighted gene correlation network analysis (WGCNA); functional enrichment analysis was also performed. A protein-protein interaction (PPI) network was constructed and pivotal genes were identified using Cytoscape. Finally, traditional Chinese medicine (TCM)formulas related to treating GDM were collected, then the proteins corresponding to the key genes were molecularly docked with the small molecular structures of clinically proven effective herbal tonics, and molecular dynamic simulations were performed to select the best candidates for pharmacological compounds.

Results

Elevated ferritin levels in patients with GDM were verified using clinical data. The presence of ferroptosis in placental tissues of patients with GDM was confirmed using electron microscopy and western blotting. Ninety-nine key genes with the highest correlation with ferroptosis were identified from DEGs and weighted gene co-expression network analysis (WGCNA). Analysis using the Kyoto Encyclopedia of Genes and Genomes demonstrated that the DEGs were primarily involved in the oxidative phosphorylation pathway. The key genes were further screened by PPI; two key genes, SF3B14 and BABAM1, were identified by combining the gene corresponding to protein structure and function, followed by molecular docking and molecular dynamic simulation. Coptis chinensis was proposed as the best candidate for herbal treatment at the molecular level.

Conclusion

This data revealed the presence of ferroptosis in patients with GDM and identified possible modulatory roles of ferroptosis-related genes involved in the molecular mechanisms of GDM, providing new insights into the pathogenesis of GDM, which also provided new directions for the systematic optimization of TCM formulas for the management and targeted treatment of GDM.

LncRNA HCG27 Promotes Glucose Uptake Ability of HUVECs by MiR-378a-3p/MAPK1 Pathway

OBJECTIVE

Gestational diabetes mellitus (GDM) is the most common metabolic disorder during pregnancy. LncRNA HLA complex group 27 (HCG27) plays a crucial role in various metabolic diseases. However, the relationship between lncRNA HCG27 and GDM is not clear. This study aimed to verify a competing endogenous RNA (ceRNA) interaction regulation axis of miR-378a-3p/mitogen-activated protein kinase 1 (MAPK1) regulated by HCG27 in GDM.

METHODS

LncRNA HCG27 and miR-378a-3p were detected by RT-qPCR. The expression of MAPK1 in umbilical vein endothelial cells (HUVECs) was detected by RT-qPCR and that in the placenta by Western blotting. To explore the relationship among lncRNA HCG27, miR-378a-3p, MAPK1 and the glucose uptake ability of HUVECs, vector HCG27, si-HCG27, miR-378a-3p mimic and inhibitor were transfected to achieve overexpression and inhibition of HCG27 or miR-378a-3p. The interaction between miR-378a-3p and lncRNA HCG27 or MAPK1 was confirmed by the dual-luciferase reporter assay. Besides, glucose consumption by HUVECs was detected by the glucose assay kit.

RESULTS

HCG27 expression was significantly decreased in both the placenta and primary umbilical vein endothelial cells, while the expression of miR-378a-3p was significantly increased in GDM tissues, and the expression of MAPK1 was decreased in GDM tissues. This ceRNA interaction regulation axis was proved to affect the glucose uptake function of HUVECs. The transfection of si-HCG27 could significantly reduce the expression of the MAPK1 protein. If the MAPK1 overexpression plasmid was transfected simultaneously with si-HCG27 transfection, the reduced glucose uptake in HUVECs resulting from the decrease in lncRNA HCG27 was reversed. MiR-378a-3p mimic can significantly reduce the mRNA expression of MAPK1 in HUVECs, whereas miR-378a-3p inhibitor can significantly increase the mRNA expression of MAPK1. The inhibition of miR-378a-3p could restore the decreased glucose uptake of HUVECs treated with si-HCG27. Besides, overexpression of lncRNA HCG27 could restore the glucose uptake ability of the palmitic acid-induced insulin resistance model of HUVECs to normal.

CONCLUSION

LncRNA HCG27 promotes glucose uptake of HUVECs by miR-378a-3p/MAPK1 pathway, which may provide potential therapeutic targets for GDM. Besides, the fetal umbilical cord blood and umbilical vein endothelial cells collected from pregnant women with GDM after delivery could be used to detect the presence of adverse molecular markers of metabolic memory, so as to provide guidance for predicting the risk of cardiovascular diseases and health screening of offspring.

Milk Exosomes from Gestational Diabetes Mellitus (GDM) and Healthy Parturient Exhibit Differential miRNAs Profiles and Distinct Regulatory Bioactivity on Hepatocyte Proliferation

SCOPE

Exosomes, a novel type of bioactive component in human milk (HM), affect infant development, growth, and health. Recent studies indicate that HM exosomes and miRNAs relate to gestational diabetes mellitus (GDM). However, the miRNAs profiles and functionalities of HM exosomes from GDM parturient remain unclear. This study aims to compare the differential miRNAs in HM exosomes from GDM and healthy parturient, and investigate the HM exosomes bioactivities in regulating hepatocyte proliferation and insulin sensitivity.

METHODS AND RESULTS

This study extracted HM exosomes from GDM (GDM-EXO) and healthy (NOR-EXO) parturient by ultracentrifugation, high-throughput sequenced and compared the exosomal miRNAs profiles, and explored the regulatory bioactivities on hepatocyte proliferation in HepG2 cells and Balb/c mice. As compared to NOR-EXO, GDM-EXO has similar morphology, size, concentration, and exosome-specific markers (CD9 and TSG101) expression. GDM-EXO and NOR-EXO specifically harbor 1299 and 8 miRNAs, respectively. Moreover, GDM-EXO had 176 upregulated and 47 downregulated miRNAs compared with NOR-EXO. Both GDM-EXO and NOR-EXO were absorbed in cultured HepG2 hepatocytes and mice liver. GDM-EXO inhibited hepatocytes proliferation by downregulating mammalian target of rapamycin (mTOR) possibly via exosomal miR-101-3p delivery.

CONCLUSION

HM exosomes from GDM and healthy parturient exhibit differential miRNAs profiles and distinct regulatory bioactivity on hepatocyte proliferation.

Epigenetic marks associated with gestational diabetes mellitus across two time points during pregnancy

An adverse intrauterine or periconceptional environment, such as hyperglycemia during pregnancy, can affect the DNA methylation pattern both in mothers and their offspring. In this study, we explored the epigenetic profile in maternal peripheral blood samples through pregnancy to find potential epigenetic biomarkers for gestational diabetes mellitus (GDM), as well as candidate genes involved in GDM development. We performed an epigenome-wide association study in maternal peripheral blood samples in 32 pregnant women (16 with GDM and 16 non-GDM) at pregnancy week 24-28 and 36-38. Biochemical, anthropometric, and obstetrical variables were collected from all the participants. The main results were validated in an independent cohort with different ethnic origin (European = 307; South Asians = 165). Two hundred and seventy-two CpGs sites remained significantly different between GDM and non-GDM pregnant women across two time points during pregnancy. The significant CpG sites were related to pathways associated with type I diabetes mellitus, insulin resistance and secretion. Cg01459453 (SELP gene) was the most differentiated in the GDM group versus non-GDM (73.6 vs. 60.9, p = 1.06E-11; FDR = 7.87E-06). Three CpG sites (cg01459453, cg15329406, and cg04095097) were able to discriminate between GDM cases and controls (AUC = 1; p = 1.26E-09). Three differentially methylated positions (DMPs) were replicated in an independent cohort. To conclude, epigenetic marks during pregnancy differed between GDM cases and controls suggesting a role for these genes in GDM development. Three CpGs were able to discriminate GDM and non-GDM groups with high specificity and sensitivity, which may be biomarker candidates for diagnosis or prediction of GDM.

Exploring the potential of microRNA as a diagnostic tool for gestational diabetes

MicroRNAs (miRNAs) are small non-coding RNAs that play critical roles in regulating host gene expression. Recent studies have indicated a role of miRNAs in the pathogenesis of gestational diabetes mellitus (GDM), a common pregnancy-related disorder characterized by impaired glucose metabolism. Aberrant expression of miRNAs has been observed in the placenta and/or maternal blood of GDM patients, suggesting their potential use as biomarkers for early diagnosis and prognosis. Additionally, several miRNAs have been shown to modulate key signaling pathways involved in glucose homeostasis, insulin sensitivity, and inflammation, providing insights into the pathophysiology of GDM. This review summarizes the current knowledge on the dynamics of miRNA in pregnancy, their role in GDM as well as their potential as diagnostic and therapeutic targets.

Association of solute carrier family 30 A8 zinc transporter gene variations with gestational diabetes mellitus risk in a Chinese population

Background

The solute carrier family 30 A8 zinc transporter (SLC30A8) plays a crucial role in insulin secretion. This study aimed to investigate the impact of SLC30A8 gene polymorphisms on gestational diabetes mellitus (GDM).

Methods

The research objective was to select 500 patients with GDM and 502 control subjects. Rs13266634 and rs2466293 were genotyped using the SNPscan™ genotyping assay. Statistical tests, such as the chi-square test, t-test, logistic regression, ANOVA, and meta-analysis, were conducted to determine the differences in genotypes, alleles, and their associations with GDM risk.

Results

Statistically significant differences were observed in age, pregestational BMI, SBP, DBP, and parity between individuals with GDM and healthy subjects (P < 0.05). After adjusting for these factors, rs2466293 remained significantly associated with an increased risk of GDM in overall subjects (GG+AG vs. AA: OR = 1.310; 95% CI: 1.005-1.707; P = 0.046, GG vs. AA: OR = 1.523; 95% CI: 1.010-2.298; P = 0.045 and G vs. A: OR = 1.249; 95% CI: 1.029-1.516; P = 0.024). Rs13266634 was still found to be significantly associated with a decreased risk of GDM in individuals aged ≥ 30 years (TT vs. CT+CC: OR = 0.615; 95% CI: 0.392-0.966; P = 0.035, TT vs. CC: OR = 0.503; 95% CI: 0.294-0.861; P = 0.012 and T vs. C: OR =0.723; 95% CI: 0.557-0.937; P = 0.014). Additionally, the haplotype CG was found to be associated with a higher risk of GDM (P < 0.05). Furthermore, pregnant women with the CC or CT genotype of rs13266634 exhibited significantly higher mean blood glucose levels than those with the TT genotype (P < 0.05). Our findings were further validated by the results of a meta-analysis.

Conclusion

The SLC30A8 rs2466293 polymorphism was found to be associated with an increased risk of GDM, while rs13266634 was associated with a decreased risk of GDM in individuals aged ≥ 30 years. These findings provide a theoretical basis for GDM testing.

Saudi Community-Based Screening Study on Genetic Variants in β-Cell Dysfunction and Its Role in Women with Gestational Diabetes Mellitus

BACKGROUND

Diabetes (hyperglycemia) is defined as a multifactorial metabolic disorder in which insulin resistance and defects in pancreatic β-cell dysfunction are two major pathophysiologic abnormalities that underpin towards gestational diabetes mellitus (GDM). TCF7L2, KCNQ1, and KCNJ11 genes are connected to the mechanism of β-cell dysfunction. The purpose of this study was to investigate the genes associated with β-cell dysfunction and their genetic roles in the rs7903146, rs2237892, and rs5219 variants in Saudi women diagnosed with type 2 diabetes mellitus and GDM.

MATERIALS AND METHODS

In this case-control study, 100 women with GDM and 100 healthy volunteers (non-GDM) were recruited. Genotyping was performed using polymerase chain reaction (PCR), followed by restriction fragment length analysis. Validation was performed using Sanger sequencing. Statistical analyses were performed using multiple software packages.

RESULTS

Clinical studies showed a β-cell dysfunction positive association in women with GDM when compared to non-GDM women (p < 0.05). Both rs7903146 (CT vs. CC: OR-2.12 [95%CI: 1.13-3.96]; p = 0.01 & T vs. C: (OR-2.03 [95%CI: 1.32-3.11]; p = 0.001) and rs5219 SNPs (AG vs. AA: OR-3.37 [95%CI: 1.63-6.95]; p = 0.0006 & G vs. A: OR-3.03 [95%CI: 1.66-5.52]; p = 0.0001) showed a positive association with genotype and allele frequencies in women with GDM. ANOVA analysis confirmed that weight (p = 0.02), BMI (p = 0.01), and PPBG (p = 0.003) were associated with rs7903146 and BMI (p = 0.03) was associated with rs2237892 SNPs.

CONCLUSIONS

This study confirms that the SNPs rs7903146 (TCF7L2) and rs5219 (KCNJ11) are strongly associated with GDM in the Saudi population. Future studies should address the limitations of this study.

Association of miR-196a2 and miR-27a polymorphisms with gestational diabetes mellitus susceptibility in a Chinese population

Introduction

MiR-196a2 and miR-27a play a key role in the regulation of the insulin signaling pathway. Previous studies have indicated that miR-27a rs895819 and miR-196a2 rs11614913 have a strong association with type 2 diabetes (T2DM), but very few studies have investigated their role in gestational diabetes mellitus (GDM).

Methods

A total of 500 GDM patients and 502 control subjects were enrolled in this study. Using the SNPscan™ genotyping assay, rs11614913 and rs895819 were genotyped. In the data treatment process, the independent sample t test, logistic regression and chi-square test were used to evaluate the differences in genotype, allele, and haplotype distributions and their associations with GDM risk. One-way ANOVA was conducted to determine the differences in genotype and blood glucose level.

Results

There were obvious differences in prepregnancy body mass index (pre-BMI), age, systolic blood pressure (SBP), diastolic blood pressure (DBP) and parity between GDM and healthy subjects (P &lt; 0.05). After adjusting for the above factors, the miR-27a rs895819 C allele was still associated with an increased risk of GDM (C vs. T: OR=1.245; 95% CI: 1.011-1.533; P = 0.039) and the TT-CC genotype of rs11614913-rs895819 was related to an increased GDM risk (OR=3.989; 95% CI: 1.309-12.16; P = 0.015). In addition, the haplotype T-C had a positive interaction with GDM (OR=1.376; 95% CI: 1.075-1.790; P=0.018), especially in the 18.5 ≤ pre-BMI &lt; 24 group (OR=1.403; 95% CI: 1.026-1.921; P=0.034). Moreover, the blood glucose level of the rs895819 CC genotype was significantly higher than that of the TT and TC genotypes (P &lt; 0.05). The TT-CC genotype of rs11614913-rs895819 showed that the blood glucose level was significantly higher than that of the other genotypes.

Discussion

Our findings suggest that miR-27a rs895819 is associated with increased GDM susceptibility and higher blood glucose levels.

Association of the CDKAL1 gene polymorphism with gestational diabetes mellitus in Chinese women

INTRODUCTION

To identify the association of the cyclin-dependent kinase 5 regulatory subunit associated protein 1-like 1 (CDKAL1) gene polymorphism with gestational diabetes mellitus (GDM) in the Chinese population.

RESEARCH DESIGN AND METHODS

This case-control study enrolled 835 pregnant women with GDM and 870 pregnant women without diabetes who underwent antenatal examination during 24 to 28 gestational weeks at the Maternal and Child Health Hospital of Hubei Province from January 15, 2018 to March 31, 2019. Trained nurses collected their clinical information and blood samples. CDKAL1 gene rs10440833, rs10946398, rs4712523, rs4712524, rs7754840, rs7756992 and rs9465871 loci were genotyped by Agena MassARRAY system. SPSS V.26.0 software and online SHesis were used to analyze the relationship between CDKAL1 gene polymorphism and GDM susceptibility.

RESULTS

After being adjusted for maternal age, prepregnancy body mass index (BMI), parity and family history of type 2 diabetes mellitus (T2DM), CDKAL1 gene rs10440833 (AA vs TT, OR=1.631, 95% CI 1.192 to 2.232), rs10946398 (CC vs AA, OR=1.400, 95% CI 1.028 to 1.905), rs4712523 (GG vs AA, OR=1.409, 95% CI 1.038 to 1.913), rs4712524 (GG vs AA, OR=1.418, 95% CI 1.043 to 1.929) and rs7754840 (CC vs GG, OR=1.407, 95% CI 1.036 to 1.911) polymorphisms were all associated with the increased risk of GDM. In addition, there was a powerful linkage disequilibrium (LD) among rs10946398, rs4712523, rs4712524 and rs7754840 (D'>0.900, r²>0.900). And there were significant differences in haplotype CGGC (OR=1.207, 95% CI 1.050 to 1.387) and AAAG (OR=0.829, 95% CI 0.721 o 0.952, p=0.008) between the GDM group and the control group.

CONCLUSIONS

rs10440833, rs10946398, rs4712523, rs4712524 and rs7754840 of CDKAL1 gene are associated with GDM susceptibility in central Chinese population.

Expression of microRNAs in patients with gestational diabetes mellitus: a systematic review and meta-analysis

BACKGROUND

MicroRNAs (miRNA) are noncoding RNAs that play a central role in governing various physiological and pathological processes. There are few studies on miRNA involvement in gestational diabetes mellitus (GDM). In this study, we performed a meta-analysis of the miRNA expression profiling from GDM patients.

METHODS

Guided by the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols, we performed a systematic search of the PubMed, Cochrane Library, and EMBASE databases from inception to December 20, 2021, to retrieve the original research studies. All the relevant data were retrieved, analyzed, and summarized.

RESULTS

Six studies (252 GDM cases and 309 controls) were included and analyzed. The six studies reported the expressions of 21 miRNAs in GDM cases. Of the 21 miRNAs, 12 miRNAs were found to be upregulated, and two were downregulated. The top three most consistently reported upregulated miRNAs were miR-16-5p (mean differences of fold change are 1.25, 95% CI = 0.04-2.46, P = 0.040), miR-19a-3p (mean differences of fold change are 2.90, 95% CI = 1.45-4.35, P = 0.001), and miR-19b-3p (mean differences of fold change are 3.10, 95% CI = 0.94-5.25, P = 0.005). miR-155-5p and miR-21-3p were found to be downregulated.

CONCLUSIONS

The results indicate that several miRNAs may be used as markers for diabetes gestational diabetes mellitus. In the future, more studies are needed to validate the findings of our study.

Circulating microRNA as Biomarkers for Gestational Diabetes Mellitus-A Systematic Review and Meta-Analysis

Gestational diabetes mellitus (GDM) is a severe pregnancy complication for both the woman and the child. Women who suffer from GDM have a greater risk of developing Type 2 diabetes mellitus (T2DM) later in life. Identification of any potential biomarkers for the early prediction of gestational diabetes can help prevent the disease in women with a high risk. Studies show microRNA (miRNA) as a potential biomarker for the early discovery of GDM, but there is a lack of clarity as to which miRNAs are consistently altered in GDM. This study aimed to perform a systematic review and meta-analysis to investigate miRNAs associated with GDM by comparing GDM cases with normoglycemic controls. The systematic review was performed according to PRISMA guidelines with searches in PubMed, Web of Science, and ScienceDirect. The primary search resulted in a total of 849 articles, which were screened according to the prior established inclusion and exclusion criteria. Following the screening of articles, the review was based on the inclusion of 35 full-text articles, which were evaluated for risk of bias and estimates of quality, after which data were extracted and relative values for miRNAs were calculated. A meta-analysis was performed for the miRNA species investigated in three or more studies: MiR-29a, miR-330, miR-134, miR-132, miR-16, miR-223, miR-155, miR-122, miR-17, miR-103, miR-125, miR-210, and miR-222. While some miRNAs showed considerable between-study variability, miR-29a, miR-330, miR-134, miR-16, miR-223, and miR-17 showed significant overall upregulation in GDM, while circulating levels of miR-132 and miR-155 were decreased among GDM patients, suggesting further studies of these as biomarkers for early GDM discovery.

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.

Arsenic metabolism, N6AMT1 and AS3MT single nucleotide polymorphisms, and their interaction on gestational diabetes mellitus in Chinese pregnant women

BACKGROUND

Single nucleotide polymorphisms (SNPs) in N6AMT1 and AS3MT are associated with arsenic (As) metabolism, and efficient As methylation capacity has been associated with diabetes. However, little is known about the gene-As interaction on gestational diabetes mellitus (GDM).

OBJECTIVE

This study aimed to explore the individual and combined effects of N6AMT1 and AS3MT SNPs with As metabolism on GDM.

METHODS

A cross-sectional study was performed among 385 Chinese pregnant women (86 GDM and 299 Non-GDM). Four SNPs in N6AMT1 (rs1997605 and rs1003671) and AS3MT (rs1046778 and rs11191453) were genotyped. Urinary inorganic arsenic (iAs), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) were determined, and the percentages of As species (iAs%, MMA%, and DMA%) were calculated to assess the efficiency of As metabolism.

RESULTS

Pregnant women with N6AMT1 rs1997605 AA genotype had lower iAs% (B: 2.11; 95% CI: 4.08, -0.13) and MMA% (B: 0.21; 95% CI: 0.39, -0.04) than pregnant women with GG genotype. The AS3MT rs1046778 and rs11191453 C alleles were negatively associated with iAs% and MMA% but positively associated with DMA%. Higher urinary MMA% was significantly associated with a lower risk of GDM (OR: 0.54; 95% CI: 0.30, 0.97). The A allele in N6AMT1 rs1997605 (OR: 0.46; 95% CI: 0.26, 0.79) was associated with a decreased risk of GDM. The additive interactions between N6AMT1 rs1997605 GG genotypes and lower iAs% (AP: 0.50; 95% CI: 0.01, 0.99) or higher DMA% (AP: 0.52; 95% CI: 0.04, 0.99) were statistically significant. Similar additive interactions were also found between N6AMT1 rs1003671 GG genotypes and lower iAs% or higher DMA%.

CONCLUSIONS

Genetic variants in N6AMT1 and efficient As metabolism (indicated by lower iAs% and higher DMA%) can interact to influence GDM occurrence synergistically in Chinese pregnant women.

Circulating lncRNAs NONHSAT054669.2 and ENST00000525337 can be used as early biomarkers of gestational diabetes mellitus

Early diagnosis can help prevent and reduce the adverse effects of gestational diabetes mellitus (GDM). This study intended to investigate key circulating long non-coding RNAs (lncRNAs) as novel biomarkers for diagnosis of GDM at the early stages. First, lncRNA microarray analysis was conducted for plasma samples of GDM women before delivery and 48 h after delivery. The expression of differentially expressed lncRNAs in clinical samples at different trimesters was randomly validated by quantitative polymerase chain reaction (PCR). Moreover, the correlation between lncRNA expression and oral glucose tolerance test (OGTT) level in GDM women during the second trimester was analyzed, followed by evaluating the diagnostic value of key lncRNAs during different trimesters using receiver operating characteristic (ROC) curve. Higher NONHSAT054669.2 expression and lower ENST00000525337 expression were revealed in GDM women before delivery relative to 48 h after delivery (P < 0.05). The expression of NONHSAT054669.2 and ENST00000525337 in GDM women during the first and second trimesters was dramatically higher than pregnant women (P < 0.05) with normal glucose tolerance (NGT). During the second trimester, NONHSAT054669.2 expression was positively related to OGTT level at 1 h (r = 0.41455, P < 0.001). Furthermore, ROC curve analysis revealed that ENST00000525337 alone, NONHSAT054669.2 alone, and their combination had high diagnostic value for GDM during the first (area under the ROC curve (AUC) = 0.979, 0.956, and 0.984, respectively) and second (AUC = 0.829, 0.809, and 0.838, respectively) trimesters (all P < 0.001). The plasma level of NONHSAT054669.2 and ENST00000525337 may be applied as novel diagnostic biomarkers for early diagnosis of GDM.

Obesity and risk of gestational diabetes mellitus: A two-sample Mendelian randomization study

AIMS

To estimate genetically predicted causal associations of general and central obesity with GDM, and to determine the mediating role of circulating lipids.

METHODS

Summary-level data was obtained from the largest available genome-wide association studies of five obesity traits, five lipid traits and GDM. Two-sample univariate Mendelian randomization (MR), multivariate MR, and MR-based mediation analysis was applied to determine the total effect, direct effect and the mediating effect, respectively.

RESULTS

Univariate MR showed that the odds of GDM increased per 1-SD increase in body mass index (BMI) (OR = 1.64, P = 5.05 × 10^-17), waist-to-hip ratio (WHR) (OR = 1.57, P = 2.27 × 10^-14) and WHR adjusted for BMI (OR = 1.42, P = 6.11 × 10^-15). The heterogeneous associations of waist circumference (OR = 1.64, P = 5.57 × 10^-14) and hip circumference (OR = 1.20, P = 0.002) on GDM further reflected that body fat distribution could influence GDM risk. Mediation analysis suggested that triglycerides, high-density lipoprotein-cholesterol and apolipoprotein A-I each mediated between 5% and 10% of the association between obesity and GDM.

CONCLUSION

Our findings supported a deleterious causal effect of obesity on GDM risk, where lipid metabolism acted as potential drivers of the relationships between both general and central obesity and GDM.

[Cholesterol 7α-Hydroxylase Gene-204A/C Polymorphism in Normal and Gestational Diabetic Pregnancies]

Objective

To investigate the cholesterol 7α-hydroxylase gene ( CYP7A1)-204A/C single nucleotide polymorphism and its relationship with the blood lipid levels of pregnant women with gestational diabetes mellitus (GDM) and normal pregnant women.

Methods

The genotype and allele frequencies of CYP7A1-204A/C gene polymorphism of 1037 normal pregnant women, the normal controls, and 627 pregnant women with GDM were examined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. Total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and blood glucose (Glu) were measured by enzymatic assay. Chemiluminescence determination of plasma insulin (Ins) was conducted. Apolipoproteins A1 (apoA1) and B (apoB) were measured by the turbidimetric immunoassay.

Results

Allele frequencies of A and C at the CYP7A1-204A/C polymorphic locus were 0.586 and 0.414, respectively, in the GDM group and 0.557 and 0.443, respectively in the control group. The distribution of genotype frequencies in both groups showed conformity with the Hardy-Weinberg principle. There was no significant difference in allele and genotype frequencies between the GDM group and the control group. In the control group, carriers of the genotype AA were associated with significantly higher concentrations of apoA1 and lower levels of Ins and homeostatic model assessment of insulin resistance (HOMA-IR) compared with those with genotype CC (all P<0.05). In the non-obese subgroup of the control subjects, carriers of the genotype CC were associated with significantly higher plasma TG or apoA1 levels compared with those with genotype AA ( P<0.05). In the GDM group, carriers with genotype AA of CYP7A1-204A/C polymorphism had elevated levels of gestational weight gain (GWG) compared with those with genotype CC ( P<0.05).

Conclusion

These results suggest that 204A/C polymorphism in the CYP7A1 gene is not associated with GDM, but may be closely associated with gestational weight gain in pregnant women with GDM. Variants in this locus are strongly associated with plasma apoA1, Ins, and HOMA-IR levels in the controls and elevated plasma TG levels in non-obese controls.