Relationship between melatonin receptor 1B and insulin receptor substrate 1 polymorphisms with gestational diabetes mellitus: a systematic review and meta-analysis

Association between insulin receptor substrate 1 gene polymorphism rs1801278 and gestational diabetes mellitus: an updated meta- analysis

OBJECTIVES

we performed this meta- analysis to investigate the impact of insulin receptor substrate 1 (IRS1) gene rs1801278 on susceptibility to gestational diabetes mellitus (GDM).

METHODS

The pooled odds ratio (OR) and 95% confidence interval (95% CI) were calculated, and p value is used to determine statistical significance. Sensitivity analysis was performed under three models (dominant, recessive and allele model), and the pooled ORs and 95%CI were calculated. Funnel plots and Begger's regression test were employed to test the publication bias.

RESULTS

The meta-analysis included 4777 participants (2116 cases and 2661 controls). The IRS1 rs1801278 (C/T) were not significant associated with GDM risk under the dominant and allele models, OR (95%CI) = 1.22 (0.88-1.70) and 1.24 (0.91-1.68), respectively (both p values were more than 0.05). But we also found the IRS1 rs1801278 (C/T) were significant associated with GDM risk under the recessive model, OR (95%CI) = 0.37 (0.16-0.86), p = 0.030. Our results showed that none of the studies affected the quality of the pooled OR. We also found no significant publication bias existed in this meta study for three genetic models, PTT + CT vs. CC = 0.445; PCC+CT vs. TT= 0.095; PC vs. T = 0.697.

CONCLUSION

this meta-analysis indicated that IRS1 rs1801278 (C/T) was associated with the GDM risk under the recessive model but was not associated with the GDM risk under dominant and allele models.

Genetic and Epigenetic Factors in Gestational Diabetes Mellitus Pathology

Gestational diabetes (GDM) is the carbohydrate intolerance occurring during pregnancy. The risk factors of GDM include obesity, advanced maternal age, polycystic ovary syndrome, multigravidity, a sedentary lifestyle, and pre-existing hypertension. Additionally, complex genetic and epigenetic processes are also believed to play a crucial role in the development of GDM. In this narrative review, we discuss the role of genetic and epigenetic factors in gestational diabetes mellitus pathogenesis.

The Role of Melatonin in Pregnancy and the Health Benefits for the Newborn

In the last few years, there have been significant evolutions in the understanding of the hormone melatonin in terms of its physiology, regulatory role, and potential utility in various domains of clinical medicine. Melatonin's properties include, among others, the regulation of mitochondrial function, anti-inflammatory, anti-oxidative and neuro-protective effects, sleep promotion and immune enhancement. As it is also bioavailable and has little or no toxicity, it has been proposed as safe and effective for the treatment of numerous diseases and to preserve human health. In this manuscript, we tried to evaluate the role of melatonin at the beginning of human life, in pregnancy, in the fetus and in newborns through newly published literature studies.

Melatonin receptor gene polymorphisms as a risk factor in patients with diabetic peripheral neuropathy

AIMS

Oxidative stress plays an important role in the pathogenesis of diabetic peripheral neuropathy (DPN). Melatonin is one of the most powerful endogenous antioxidants and has anti-inflammatory properties. We investigated how the gene polymorphism of melatonin differs in patients with DPN compared to an healthy control group.

MATERIALS AND METHODS

A total of 54 diabetic peripheral neuropathy patients who applied to the Neurology outpatient clinic between 2020 and 2021, and 53 healthy controls comparable with the patient group in terms of age and gender were included in the study. Electromyography was performed and the melatonin gene polymorphism was analysed using the pyrosequencing method.

RESULTS

Melatonin gene variants rs2119882, rs13140012, and rs10830963 were analysed in patients and controls. The rs2119882 (G allele) has a protective role, and rs13140012 polymorphism has a related 5-fold higher risk of DPN in the recessive model.

CONCLUSIONS

Melatonin gene polymorphisms have been shown to be associated with DPN. This is the first and only study investigating the relationship between melatonin gene polymorphisms and DPN. Ethnicity is very important in genetic studies, and it will give us more information on the role of melatonin gene variants in larger study groups of diabetic patients of other ethnic origin.

Pathophysiological Role of Genetic Factors Associated With Gestational Diabetes Mellitus

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

Association of surfactant protein D gene polymorphism with susceptibility to gestational diabetes mellitus: a case-control study

Background

Surfactant protein D (SP-D) is a critical component of the innate immune system intrinsically linked to energy metabolism. However, the relationship of SP-D gene polymorphisms and gestational diabetes mellitus (GDM) remains unclear. In this study, we analyzed SP-D gene polymorphisms in GDM patients and nondiabetic controls and then determined the association of SP-D gene polymorphisms with GDM.

Methods

We examined a common genetic polymorphism located in the SP-D coding region (rs721917, Met31Thr) in GDM patients (n = 147) and healthy pregnant controls (n = 97) by using a cleaved amplification polymorphism sequence-tagged sites (PCR–RFLP) technique. The level of SP-D protein in the serum of GDM patients and nondiabetic controls was determined by ELISA. The gene and allele frequencies of SP-D and their association with GDM as well as SP-D protein levels were analyzed and expressed as odds ratios (ORs) with 95% confidence intervals (95% CIs).

Results

We found that there was a significant association of the SP-D polymorphism (rs721917) with GDM. The SP-D (T/T) genotype was found in 11.6% and 21.6% of GDM patients and matched healthy controls, respectively (odds ratio, 0.473; 95% confidence interval, 0.235–0.952; P = 0.033), indicating that women with the (T/T) genotype had a lower prevalence of GDM (OR = 0.473). Women with the T/C genotype showed an increased risk of GDM (odds ratio, 2.440; 95% confidence interval, 1.162–5.123; P = 0.017). We did not observe corrections between glucose homeostasis markers and SP-D genotypes in women with GDM. Furthermore, serum SP-D levels were higher in GDM patients than in matched healthy controls.

Conclusions

This study found the first evidence that an SP-D gene polymorphism (rs721917) was associated with GDM, which may provide the basis for further study on how SP-D plays a regulatory role in GDM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04541-1.

Urinary Angiotensinogen-Melatonin Ratio in Gestational Diabetes and Preeclampsia

Background: A large research portfolio indicates that an activated renal renin-angiotensin system or a deficit on melatonin is associated with several cardiovascular pathologies. In this observational clinical study, we hypothesized that alterations in urinary melatonin or angiotensinogen levels may be altered in two common conditions, preeclampsia and gestational diabetes. Our study’s primary objective was to assess melatonin and angiotensinogen as novel disease biomarkers detectable and quantifiable in the urine of pregnant women with or without pregnancy complications.

Methods: This was a concurrent cohort study of pregnant women with selected obstetric pathologies (gestational diabetes, preeclampsia, hypertension and obesity with hypertension). A group of healthy controls was also included. Urinary 6-sulfatoxymelatonin and angiotensinogen were measured by sensitive and specific ELISAs in first morning void urine samples. The patients were included in the cohort consecutively, and the diagnosis was blinded at the level of urine collection. Urinary 6-sulfatoxymelatonin and angiotensinogen levels were investigated in the patients included in the cohort.

Results: Urinary levels of angiotensinogen were significantly higher in the gestational diabetes [angiotensinogen/creatinine ratio median (25th, 75th): 0.11 (0.07, 0.18)] and preeclampsia [0.08 (0.06, 0.18)] groups than in those with healthy pregnancy [0.05(0.04, 0.06]; 6-sulfatoxymelatonin levels were significantly lower in the gestational diabetes [ug/h: median (25th, 75th): 0.12(0.08, 0.17)] and preeclampsia [0.12 (0.09, 0.15)] groups than in those with healthy pregnancy [0.20 (0.15, 0.27]. Neither morning void protein/creatinine ratio nor 24-h urine protein estimate were significantly different between the study groups.

Conclusion: These results suggest that urinary angiotensinogen levels may indicate an intrarenal RAS activation while melatonin production appears to be defective in gestational diabetes or hypertension. An angiotensinogen/melatonin ratio is suggested as an early biomarker for identification of gestational diabetes or hypertension. This report provides a basis for the potential use of melatonin for the treatment of preeclampsia. A prospective study in a larger number of patients to determine the operative characteristics of these markers as potential diagnostic tests is justified.

An early prediction model for gestational diabetes mellitus based on genetic variants and clinical characteristics in China

OBJECTIVES

To evaluate the influence of genetic variants and clinical characteristics on the risk of gestational diabetes mellitus (GDM) and to construct and verify a prediction model of GDM in early pregnancy.

METHODS

Four hundred seventy five women with GDM and 487 women without, as a control, were included to construct the prediction model of GDM in early pregnancy. Both groups had complete genotyping results and clinical data. They were randomly divided into a trial cohort (70%) and a test cohort (30%). Then, the model validation cohort, including 985 pregnant women, was used for the external validation of the GDM early pregnancy prediction model.

RESULTS

We found maternal age, gravidity, parity, BMI and family history of diabetes were significantly associated with GDM (OR > 1; P < 0.001), and assisted reproduction was a critical risk factor for GDM (OR = 1.553, P = 0.055). MTNR1B rs10830963, C2CD4A/B rs1436953 and rs7172432, CMIP rs16955379 were significantly correlated with the incidence of GDM (AOR > 1, P < 0.05). Therefore, these four genetic susceptible single nucleotide polymorphisms (SNPs) and six clinical characteristics were included in the construction of the GDM early pregnancy prediction model. In the trial cohort, a predictive model of GDM in early pregnancy was constructed, in which genetic risk score was independently associated with GDM (AOR = 2.061, P < 0.001) and was the most effective predictor with the exception of family history of diabetes. The ROC-AUC of the prediction model was 0.727 (95% CI 0.690-0.765), and the sensitivity and specificity were 69.9% and 64.0%, respectively. The predictive power was also verified in the test cohort and the validation cohort.

CONCLUSIONS

Based on the genetic variants and clinical characteristics, this study developed and verified the early pregnancy prediction model of GDM. This model can help screen out the population at high-risk for GDM in early pregnancy, and lifestyle interventions can be performed for them in a timely manner in early pregnancy.

Melatonin Receptor 1B Genetic Variants on Susceptibility to Gestational Diabetes Mellitus: A Hospital-Based Case-Control Study in Wuhan, Central China

PURPOSE

The aim of the study was to find out the associations of Melatonin receptor 1B (MTNR1B) genetic variants with gestational diabetes mellitus (GDM) in Wuhan of central China.

PATIENTS AND METHODS

A hospital-based case-control study that included 1679 women was carried out to explore the associations of MTNR1B single nucleotide polymorphisms (SNPs) with GDM risk, which were analyzed through logistic regression analysis by adjusting age, pre-pregnancy BMI and family history of diabetes. Multifactor dimensionality reduction was applied to determine gene-gene interactions between SNPs.

RESULTS

MTNR1B SNPs rs10830962, rs10830963, rs1387153, rs7936247 and rs4753426 were significantly associated with GDM risk (P<0.05). The rs10830962/G, rs10830963/G, rs1387153/T, and rs7936247/T were risk variants, whereas rs4753426/T was protective variant for GDM development. Fasting plasma glucose (FPG) and 1h-plasma glucose (PG) were significantly different among genotypes at rs10830962 and rs10830963, whereas 2h-PG levels were not. Gene-gene interactions were not found among the five SNPs on GDM risk.

CONCLUSION

MTNR1B genetic variants have significant associations but no gene-gene interactions with GDM risk in central Chinese population. Furthermore, MTNR1B SNPs have significant relationships with glycemic traits.

Gestational Diabetes Mellitus: The Genetic Susceptibility Behind the Disease

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

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

OBJECTIVES

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

DESIGN

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

METHODS

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

RESULTS

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

LIMITATIONS

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

CONCLUSIONS

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

Relationship between melatonin and high-risk pregnancy: A review of investigations published between the years 2010 and 2020

The purpose of this review was to search for articles on human studies investigating the relationship between melatonin and high-risk pregnancy. An electronic search was conducted in the MEDLINE and PubMed databases from September 2010 to October 2020. The initial search produced 441 articles in PubMed and 407 in MEDLINE. After sorting the titles and abstracts, and removing duplicates, we had nine articles in PubMed and three in Medline. The results of these studies mainly show that the association between melatonin receptor 1B polymorphisms and gestational diabetes mellitus is the most common physiological mechanism relating to melatonin and high-risk pregnancy in this review. In addition, the circadian rhythm, decreased melatonin production, and anti-inflammatory and antioxidant effects were explored. The findings of our review of the literature suggest that this indoleamine is essential in high-risk pregnancy for its potent anti-inflammatory and antioxidant effects, regulation of the circadian rhythm, and genic receptor expression.

Impact of Early Nutrition, Physical Activity and Sleep on the Fetal Programming of Disease in the Pregnancy: A Narrative Review

Early programming is the adaptation process by which nutrition and environmental factors alter development pathways during prenatal growth, inducing changes in postnatal metabolism and diseases. The aim of this narrative review, is evaluating the current knowledge in the scientific literature on the effects of nutrition, environmental factors, physical activity and sleep on development pathways. If in utero adaptations were incorrect, this would cause a mismatch between prenatal programming and adulthood. Adequate caloric intake, protein, mineral, vitamin, and long-chain fatty acids, have been noted for their relevance in the offspring brain functions and behavior. Fetus undernutrition/malnutrition causes a delay in growth and have detrimental effects on the development and subsequent functioning of the organs. Pregnancy is a particularly vulnerable period for the development of food preferences and for modifications in the emotional response. Maternal obesity increases the risk of developing perinatal complications and delivery by cesarean section and has long-term implications in the development of metabolic diseases. Physical exercise during pregnancy contributes to overall improved health post-partum. It is also interesting to highlight the relevance of sleep problems during pregnancy, which influence adequate growth and fetal development. Taking into account these considerations, we conclude that nutrition and metabolic factors during early life play a key role of health promotion and public health nutrition programs worldwide to improve the health of the offspring and the health costs of hospitalization.

A functional polymorphism rs10830963 in melatonin receptor 1B associated with the risk of gestational diabetes mellitus

The melatonin receptor 1B (MTNR1B) polymorphism rs10830963 C>G has been reported to be associated with the risk of gestational diabetes mellitus (GDM) with inconsistent results. To clarify the effect of the polymorphism on the risk of GDM, a meta-analysis therefore was performed. Pooled OR with its corresponding 95%CI was used to estimate the strength of the association. Totally 14 eligible studies with a number of 5033 GDM patients and 5614 controls were included in this meta-analysis. Results indicated that the variant G allele was significantly associated with an increased GDM risk (CG vs. CC: OR = 1.25, 95% CI = 1.11−1.40, P < 0.001; GG vs. CC: OR = 1.78, 95% CI = 1.45−2.19, P < 0.001; G vs. C: OR = 1.33, 95% CI = 1.21−1.47, P < 0.001). In the stratified analysis by ethnicity, similar results were found in Asians (CG vs. CC: OR = 1.15, 95%CI = 1.02−1.28, P = 0.020; GG vs. CC: OR = 1.52, 95% CI = 1.23−1.89, P < 0.001; G vs. C: OR = 1.23, 95% CI = 1.10−1.37, P < 0.001) and in Caucasians (CG vs. CC: OR = 1.40, 95% CI = 1.16−1.70, P < 0.001; GG vs. CC: OR = 2.21, 95% CI = 1.54−3.17, P < 0.001; G vs. C: OR = 1.47, 95% CI = 1.24−1.73, P < 0.001). FPRP and TSA analyses confirmed findings support that the rs10830963 G allele increases the risk of GDM, and further functional experimental studies are warranted to explore and clarify the potential mechanism.

A diterpene derivative enhanced insulin signaling induced by high glucose level in HepG2 cells

The predominant feature of type 2 diabetes is insulin resistance. Identifying a drug able to reduce insulin resistance is an urgent requirement. ent-3α-Formylabieta-8(14),13(15)-dien-16,12β-olide had been identified as a new diterpene derivative which showed anticancer activity. This study explores the hypoglycemic effect of ent-3α-formylabieta-8(14),13(15)-dien-16,12β-olide and studied its mechanism. The insulin response of HepG2 cells following ent-3α-formylabieta-8(14),13(15)-dien-16,12β-olide treatment, as a model for liver cancer cells, was assessed. The results demonstrated that hyperglycemia resulted in a significant increase in the levels of insulin receptor substrate-1 (IRS-1) serine phosphorylation and decrease in Akt phosphorylation. High glucose also inhibited the phosphorylation of insulin-dependent GSK3β. ent-3α-Formylabieta-8(14),13(15)-dien-16,12β-olide treatment improved the effect of insulin on the phosphorylation of IRS-1 Ser307. In addition, this study demonstrated that the effect of ent-3α-formylabieta-8(14),13(15)-dien-16,12β-olide was dependent on the activation of AMP-activated protein kinase. Collectively, experimental data indicated an association between insulin resistance and hyperglycemia in HepG2 cells, and that ent-3α-formylabieta-8(14),13(15)-dien-16,12β-olide reduces IRS-1 Ser307 phosphorylation via activating AMPK, thereby decreasing the insulin signaling blockade.

Whether the risk of gestational diabetes mellitus is affected by TNF-α, IL-6, IL-10 or ADIPOQ polymorphisms: a meta-analysis

BACKGROUND

Whether polymorphisms in tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-10 (IL-10) or adiponectin (ADIPOQ) influence the risk of gestational diabetes mellitus (GDM) or not remain inconclusive. Therefore, the authors conducted a meta-analysis to robustly assess relationships between polymorphisms in TNF-α, IL-6, IL-10 or ADIPOQ and the risk of GDM by merging the results of eligible publications.

METHODS

A through literature searching in Medline, Embase, Wanfang, VIP and CNKI was conducted by the authors to identify eligible publications, and twenty-two publications were finally found to be eligible for merged quantitative analyses.

RESULTS

The merged quantitative analyses revealed that ADIPOQ + 45T/G (rs2241766) polymorphism was significantly associated with the risk of GDM in overall population (dominant comparison: OR = 0.70, p < 0.001; recessive comparison: OR = 1.95, p < 0.001; over-dominant comparison: OR = 1.18, p = 0.03; allele comparison: OR = 0.71, p < 0.001) and Asians (dominant comparison: OR = 0.70, p < 0.001; recessive comparison: OR = 1.94, p < 0.001; allele comparison: OR = 0.72, p < 0.001). Nevertheless, we did not observe any positive results for TNF-α - 238G/A (rs361525), TNF-α - 308G/A (rs1800629), IL6 - 174G/C (rs1800795), IL-10 - 819C/T (rs1800871), IL-10 - 592C/A (rs1800872), IL-10 - 1082A/G (rs1800896) and ADIPOQ + 276G/T (rs1501299) polymorphisms.

CONCLUSIONS

The present meta-analysis shows that among investigated TNF-α, IL-6, IL-10 or ADIPOQ polymorphisms, only ADIPOQ + 45T/G (rs2241766) polymorphism may affect the risk of GDM.

Genetics and Epigenetics: New Insight on Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is the most common metabolic complication of pregnancy, with a prevalence that has increased significantly in the last decade, coming to affect 12-18% of all pregnancies. GDM is believed to be the result of a combination of genetic, epigenetic and environmental factors. Following the identification of susceptibility genes for type 2 diabetes by means of genome-wide association studies, an association has also been demonstrated between some type 2 diabetes susceptibility genes and GDM, suggesting a partial similarity of the genetic architecture behind the two forms of diabetes. More recent genome-wide association studies, focusing on maternal metabolism during pregnancy, have demonstrated an overlap in the genes associated with metabolic traits in gravid and non-gravid populations, as well as in genes apparently unique to pregnancy. Epigenetic changes-such as DNA methylation, histone modifications and microRNA gene silencing-have also been identified in GDM patients. Metabolomics has been used to profile the metabolic state of women during pregnancy, based on the measurement of numerous low-molecular-weight metabolites. Measuring amino acids and conventional metabolites has revealed changes in pregnant women with a higher insulin resistance and high blood glucose levels that resemble the changes seen in non-gravid, insulin-resistant populations. This would suggest similarities in the metabolic profiles typical of insulin resistance and hyperglycemia whether individuals are pregnant or not. Future studies combining data obtained using multiple technologies will enable an integrated systems biology approach to maternal metabolism during a pregnancy complicated by GDM. This review highlights the recent knowledge on the impact of genetics and epigenetics in the pathophysiology of GDM and the maternal and fetal complications associated with this pathology condition.

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

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

MTNR1B genetic polymorphisms as risk factors for gestational diabetes mellitus: a case-control study in a single tertiary care center

BACKGROUND

Gestational diabetes mellitus (GDM) is a metabolic disease in pregnancy that causes carbohydrate intolerance and hyper-glycemia. Genome-wide association studies and meta-analyses have found that the single nucleotide polymorphisms (SNPs) rs1387153 and rs10830963 of the melatonin receptor 1B ( MTNR1B) gene are associated with GDM. No studies on the MTNR1B gene effect on GDM have been performed in Saudis, other Arabs, or other Middle Eastern populations.

OBJECTIVES

Investigate the association of genotype or allele frequencies of the two SNPs with GDM and with clinical parameters related to GDM.

DESIGN

Case-control study.

SETTINGS

Tertiary care center, Riyadh.

PATIENTS AND METHODS

We recruited 400 pregnant Saudi women ages 18-45 years (200 were diagnosed with GDM, and 200 were healthy controls). Biochemical assays were performed, and rs1387153 and rs10830963 polymorphisms were analyzed by polymerase chain reaction-restriction fragment length polymorphism analysis and real-time polymerase chain reaction with TaqMan genotyping.

MAIN OUTCOME MEASURES

The association of MTNR1B gene (rs1387153 and rs10830963 polymorphisms) with GDM and with biochemical parameters related to GDM.

SAMPLE SIZE

200 GDM cases and 200 non-GDM controls.

RESULTS

Differences in allele frequencies for GDM vs non-GMD were statistically significant or nearly significant for both SNPs after adjustment for age and body mass index. In a logistic regression analysis, genotype TT was positively associated with post-prandial blood glucose (P=.018), but other associations were not statistically significant.

CONCLUSION

The odds ratios for the associations between the rs1387153 and rs10830963 SNPs and GDM exceeded 1.5-fold, which is higher than typically reported for diseases with complex genetic background. These effect sizes for GDM suggest pregnancy-specific factors related to the MTNR1B risk genotypes.

LIMITATIONS

Only two SNPs were studied.

CONFLICT OF INTEREST

None.

A Review of Data of Findings on Night Shift Work and the Development of DM and CVD Events: a Synthesis of the Proposed Molecular Mechanisms

PURPOSE OF REVIEW

Night shift work has become highly prevalent in our 24/7 societies, with up to 18% of the US work force working alternate shift schedules. However, studies indicate that there may be adverse health effects of chronic night work across diverse populations. These effects are likely due to misalignment of the circadian system with work schedules, mediated by the system's primary marker melatonin as well as other downstream molecules.

RECENT FINDINGS

Melatonin has multiple biologic actions that are relevant to cardiometabolic disease, including modulation of oxidative stress, inflammation, and (via the melatonin receptor) vasoconstriction. Behavioral traits, such as chronotype and meal timing, have recently been shown to interact with the effects of night work on cardiometabolic health. Together with recent findings suggesting a role for circadian genes in cardiometabolic risk, the interactions of night shift work and behavioral traits are likely to facilitate novel treatment and prevention approaches for cardiovascular disease and type 2 diabetes, incorporating aspects of clock and timing.

Association of eNOS and ACE gene polymorphisms as a genetic risk factor in gestational diabetes in Iranian women

Background

Gestational diabetes mellitus (GDM) is the most popular metabolic disease during pregnancy. The aim of the present study was to investigate any possible association between eNOS Glu298Asp and ACE I/D gene polymorphisms and the risk of GDM in a group of Iranian pregnant women.

Methods

In this case-control study 204 pregnant women were recruited (94 cases and 110 controls). Genomic DNA was isolated from whole blood and genotyping was performed by the Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR- RFLP) and only PCR for eNOS and ACE polymorphisms respectively.

Results

Frequencies of GT and TT genotype of eNOS polymorphism among women with and without GDM were 67.90% vs. 74.47 and 7.41% vs. 8.51% respectively (P = 0.4). Corresponding figures for DD genotype of ACE polymorphism among GDM patients was more than that in healthy women (51.65% vs. 63.81% respectively). Conversely, ACE heterozygote genotype was more common in diabetic women (35.16% vs. 26.67% respectively). Although these differences were not statistically significant (P = 0.2).

Conclusions

Our study showed that there is no association between the presence of eNOS and ACE gene polymorphisms and developing gestational diabetes mellitus among pregnant women in our population. Further longitudinal and multicenter studies should be carried out to assess the exact metabolic effects of these polymorphisms.

Melatonin attenuates arsenic induced nephropathy via the regulation of oxidative stress and inflammatory signaling cascades in mice

Arsenic is a potent inducer of several acute and chronic nephrotoxic disorders. It promotes deleterious phenomenon like oxidative stress, inflammation, cell death and altered glucose uptake leading to distorted kidney homeostasis that end up in chronic kidney disease. This study investigated the possible protective role of melatonin; a natural antioxidant produced by the pineal gland, against arsenic induced nephrotoxicity. Melatonin successfully ameliorated arsenic induced renal toxicity both in in vitro and in vivo models. Elevated BUN, creatinine, urine glucose and protein levels and altered renal histopathological conditions were observed in arsenic intoxicated mice. Significant oxidative stress induced damage of biomolecules along with downregulation in antioxidant enzymes and thiols were also detected in the kidney tissues of arsenic-intoxicated mice. These alterations along with mitochondrial dysfunction ultimately triggered TNFα mediated inflammatory and cell death cascades. Interestingly arsenic also led to disruption of glucose uptake in the kidney. These findings suggest that melatonin protects the kidney against toxic effect of arsenic, presumably through its antioxidant, anti-inflammatory and antidiabetic properties by inhibiting inflammatory outburst, apoptosis, necroptosis and stimulating glucose uptake. As melatonin is a natural antioxidant molecule, detailed pharmacokinetic and pharmacodynamic studies are expected to establish it as an effective nephro-protective agent in future.

SOS1 gene polymorphisms are associated with gestational diabetes mellitus in a Chinese population: Results from a nested case-control study in Taiyuan, China

Gestational diabetes mellitus is a growing public health concern due to its large disease burden; however, the underlying pathophysiology remains unclear. Therefore, we examined the relationship between 107 single-nucleotide polymorphisms in insulin signalling pathway genes and gestational diabetes mellitus risk using a nested case-control study. The SOS1 rs7598922 GA and AA genotype were statistically significantly associated with reduced gestational diabetes mellitus risk ( p_trend = 0.0006) compared with GG genotype. At the gene level, SOS1 was statistically significantly associated with gestational diabetes mellitus risk after adjusting for multiple comparisons. Moreover, AGGA and GGGG haplotypes in SOS1 gene were associated with reduced risk of gestational diabetes mellitus. Our study provides evidence for an association between the SOS1 gene and risk of gestational diabetes mellitus; however, its role in the pathogenesis of gestational diabetes mellitus will need to be verified by further studies.

The Q192R polymorphism of the paraoxonase-1 (PON1) gene is associated with susceptibility to gestational diabetes mellitus in the Greek population

A key factor protecting from oxidative stress in gestational diabetes mellitus (GDM) and in type 2 diabetes (T2D) is paraoxonase-1 (PON1). Inconclusive and limited data exist regarding the effect of a coding polymorphism (Q192R) of the PON1 gene in conferring susceptibility to both states. In the present study, we investigated the association between the PON1 gene and the risk for GDM in the Greek population and assessed for the first time its transcriptional efficiency. We studied 185 women with GDM and 104 non-diabetic controls for the PON1 polymorphism. For PON1 mRNA expression, peripheral leucocytes were harvested from 20 GDM and 20 control women, harboring different genotypes for the polymorphism, using real-time quantitative PCR. The RR genotype and the R allele of the PON1 Q192R polymorphism were significantly associated with an increased risk for GDM (p = 0.012 and p < 0.0001, respectively). Furthermore, there was no statistical correlation between the individual metabolic parameters tested and the three genotypes. Finally, the expression levels of PON1 mRNA in GDM patients did not exhibit any statistical difference compared with normal controls (p = 0.138). These data independently document that the Q192R polymorphism is closely associated with GDM susceptibility, while the PON1 gene expression is not impaired in GDM.

Effects of the Tangningtongluo formula as an alternative strategy for diabetics via upregulation of insulin receptor substrate-1

Tangningtongluo (TNTL), a traditional Chinese medicine, has been widely used in clinics for decades in southwest China. Its pharmacological properties and underlying molecular mechanisms remain unclear. The main goal of ethnopharmacology is to identify novel bioactive compounds derived from plants for use in indigenous medical practice. This knowledge can be used to develop novel pharmaceuticals. In the present study, hyperglycemic C57BL/KsJ-db/db (db/db) mice were used to test the effect of TNTL on microvasculature of the retina and hypoglycemia. Metformin (Met) was selected as a positive control. 26-week-old mice were randomly assigned to receive either the anti-diabetic agent Met [140 mg/kg body weight (BW)], 1.8, 0.9 or 0.45 g/kg BW TNTL, or a placebo. The fasting blood glucose, serum insulin and glycated hemoglobin levels were measured. Histopathologic examination of the pancreas was performed to confirm the hypoglycemic effect. Fluorescein angiography was applied to detect diabetes-induced retinal angioma in the db/db mice. TNTL intake significantly decreased the fasting blood glucose level in a dose-dependent manner. Additionally, TNTL intervention resulted in a significant decrease in the insulin resistance index. Notably, TNTL treatment markedly reduced the speed of retinal degeneration and mildly reversed microvascular caliber degeneration. Western blot analysis indicated that upregulation of phosphorylated insulin receptor substrate-1 (p-IRS-1) by the administration of TNTL may be strongly involved in the improvement of insulin resistance. In conclusion, TNTL exerted a strong hypoglycemic effect and reversed retinal degeneration via upregulation of ISR-1. The present findings provide important scientific evidence supporting TNTL as an effective alternative approach for the management of Type 2 diabetes mellitus.

MECHANISMS IN ENDOCRINOLOGY: Epigenetic modifications and gestational diabetes: a systematic review of published literature

OBJECTIVE

To summarize the current knowledge on epigenetic alterations in mother and offspring subjected to gestational diabetes (GDM) and indicate future topics for research.

DESIGN

Systematic review.

METHODS

We performed extensive searches in PubMed, EMBASE and Google scholar, using a combination of the search terms: GDM, gestational diabetes, epigenetic(s), methylation, histone modification, histone methylation, histone acetylation, microRNA and miRNA. Studies that compared women diagnosed with GDM and healthy controls were included. Two authors independently scanned the abstracts, and all included papers were read by at least two authors. The searches were completed on October 31st, 2016.

RESULTS

We identified 236 articles, of which 43 were considered relevant for this systematic review. Studies published showed that epigenetic alterations could be found in both mothers with GDM and their offspring. However, differences in methodology, diagnostic criteria for GDM and populations studied, together with a limited number of published studies and small sample sizes, preclude clear conclusions about the role of epigenetic modifications in transmitting risk from GDM mothers to their offspring.

CONCLUSION

The current research literature suggests that GDM may have impact on epigenetic modifications in the mother and offspring. However, larger studies that include multiple cohorts of GDM patients and their offspring are needed.

Association of common polymorphisms with gestational diabetes mellitus in Japanese women: A case-control study

Gestational diabetes (GDM) and type 2 diabetes (T2DM) share part of pathomechanism and several T2DM susceptibility genes are demonstrated to be associated with GDM. No information on the genetics of GDM, however, was available in Japanese women. In this study, T2DM risk variants (45 single nucleotide polymorphisms [SNPs] from 36 genes) identified in previous studies were genotyped using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry in a cohort of 171 Japanese women with GDM and 128 normal glucose tolerance (NGT) diagnosed by the new International Association of Diabetes in Pregnancy Study Group criteria. Of 45 SNPs, three genetic variants were nominally associated with the development of GDM: rs266729 (p = 0.013, odds ratio [OR]: 1.56, 95% confidence interval [CI]: 1.10-2.23) in ADIPOQ, rs10811661 (p = 0.035, OR: 1.46, 95% CI: 1.03-2.08) in CDKN2A/2B, and rs9505118 (p = 0.046, OR: 1.41, 95% CI: 1.01-1.97) in SSR1-RREB1. There was a significant difference in the number of risk alleles of three variants between women with GDM and NGT (3.79 ± 1.33 vs. 3.05 ± 1.41, p = 6.0 × 10^-6). In combined analysis of three genetic variants, women with five or more risk alleles had a 7.32-fold increased risk of GDM (p = 5.6 × 10^-5, 95% CI: 4.54-11.96), compared with those having no more than one risk allele. Our results suggest several risk variants of T2DM had cumulative effects on the development of GDM in Japanese women.

Melatonin attenuates the high-fat diet and streptozotocin-induced reduction in rat hippocampal neurogenesis

A deviant level of melatonin in blood circulation has been associated with the development of diabetes and with learning and memory deficiencies. Melatonin might have an important function in diabetes control; however, the mechanism of melatonin in diabetes remains unknown. The present study aimed to investigate the hyperglycemic condition induced by high-fat diet (HFD) feeding and streptozotocin (STZ) injection and to examine the effect of melatonin on adult hippocampal functions. HFD-fed and STZ-treated rats significantly increased blood glucose level. The present study showed that HFD-fed and STZ-treated rats significantly impaired memory in the Morris Water Maze task, reduced neurogenesis in the hippocampus shown by a reduction in nestin, doublecortin (DCX) and β-III tubulin immunoreactivities, reduced axon terminal markers, synaptophysin, reduced dendritic marker including postsynaptic density 95 (PSD-95) and the glutamate receptor subunit NR2A. Moreover, a significant downregulation of melatonin receptor, insulin receptor-β (IR-β) and both p-IR-β and phosphorylated extracellular signal-regulated kinase (p-ERK) occurred in HFD-fed and STZ-treated rats, while the level of glial fibrillary acidic protein (GFAP) increased. Treatment of melatonin, rats had shorter escape latencies and remained in the target quadrant longer compared to the HFD-fed and STZ-treated rats. Melatonin attenuated the reduction of neurogenesis, synaptogenesis and the induction of astrogliosis. Moreover, melatonin countered the reduction of melatonin receptor, insulin receptor and downstream signaling pathway for insulin. Our data suggested that the dysfunction of insulin signaling pathway occurred in the diabetes may provide a convergent mechanism of hippocampal impaired neurogenesis and synaptogenesis lead to impair memory while melatonin reverses these effects, suggesting that melatonin may reduce the pathogenesis of diabetes.

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

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

TCF7L2 involvement in estradiol- and progesterone-modulated islet and hepatic glucose homeostasis

To evaluate the role of TCF7L2, a key regulator of glucose homeostasis, in estradiol (E2) and progesterone (P4)-modulated glucose metabolism, mouse insulinoma cells (MIN6) and human liver cancer cells (hepG2 and HUH7) were treated with physiological concentrations of E2 or P4 in the up- and down-regulation of TCF7L2. Insulin/proinsulin secretion was measured in MIN6 cells, while glucose uptake and production were evaluated in liver cancer cells. E2 increased insulin/proinsulin secretion under both basal and stimulated conditions, whereas P4 increased insulin/proinsulin secretion only under glucose-stimulated conditions. An antagonistic effect, possibly concentration-dependent, of E2 and P4 on the regulation of islet glucose metabolism was observed. After E2 or P4 treatment, secretion of insulin/proinsulin was positively correlated with TCF7L2 protein expression. When TCF7L2 was silenced, E2- or P4-promoted insulin/proinsulin secretion was significantly weakened. Under glucotoxicity conditions, overexpression of TCF7L2 increased insulin secretion and processing. In liver cancer cells, E2 or P4 exposure elevated TCF7L2 expression, enhanced the activity of insulin signaling (pAKT/pGSK), reduced PEPCK expression, subsequently increased insulin-stimulated glucose uptake, and decreased glucose production. Silencing TCF7L2 eliminated effects of E2 or P4. In conclusion, TCF7L2 regulates E2- or P4-modulated islet and hepatic glucose metabolism. The results have implications for glucose homeostasis in pregnancy.

Relationship between melatonin receptor 1B (rs10830963 and rs1387153) with gestational diabetes mellitus: a case-control study and meta-analysis

PURPOSE

Variants rs10830963 (C/G) and rs1387153 (C/T) in MTNR1B have been shown with an increased risk of developing type 2 diabetes and gestational diabetes mellitus. However, the results are still controversial, and evidence was not satisfied. Hence, a case-control study and a further meta-analysis will be performed in this study.

METHODS

We recruited 674 GDM patients and 690 controls from Jan 2010 and Jan 2014. The SNPs were genotyped by ABI TaqMan SNP Genotyping Assays. MTNR1B rs10830963 and rs1387153 single nucleotide polymorphisms (SNPs) were performed for association analysis. Then a systematic search of all relevant studies was conducted. A meta-analysis was performed to prove the relationship between melatonin receptor 1B (rs10830963 and rs1387153) with GDM.

RESULTS

The case-control study presented that G allele of the rs10830963 and T allele of rs1387153 were significantly associated with increased risk of GDM. The further meta-analysis included other five studies showed that the frequency of MTNR1B rs10830963 G allele and rs1387153 T allele are higher in GDM patients.

CONCLUSION

The case-control study proved that the risk allele (G allele) of rs10830963 and (T allele) of rs1387153 lead to a higher risk for GDM. The further meta-analysis provides additional evidence supporting the above results. Due to the limited data currently available in different race population, further studies with large sample sizes are required.

Variants in Vitamin D Binding Protein Gene Are Associated With Gestational Diabetes Mellitus

To investigate whether single nucleotide polymorphisms (SNPs) within 4 representative genes (VDR, GC, CYP2R1, and CYP24A1) encoding the core proteins involved in vitamin D production, degradation, and ligand-dependent signaling pathway are associated with gestational diabetes mellitus (GDM) in a Chinese population. A total of 1494 pregnant Han Chinese women (692 women with GDM and 802 women with normal glucose served as controls) were recruited through a 2-step approach. Participants were further divided into 2 groups according to body mass index before gestation (pre-BMI) (25 kg/m2). Nine SNPs (rs3733359, rs2282679, and rs16847024 in GC, rs2060793 and rs10741657 in CYP2R1, rs2248359 and rs6013897 in CYP24A1, rs11574143 and rs739837 in VDR) were genotyped using TaqMan allelic discrimination assays. The relationships between genotypes/alleles of a single locus as well as haplotypes of each gene and GDM were analyzed. We did not observe a significant difference in genotype frequency of each SNP between cases and controls. However, in the obese subgroup (pre-BMI ≥ 25 kg/m2), the risk allele-A of rs3733359 showed an association with increased risk of GDM (OR = 1.739, 95% CI = 1.066-2.837, P = 0.027). The GG-haplotype frequency of rs3733359 and rs2282679 in GC was modestly lower in the GDM group (OR = 0.848, 95% CI = 0.719-0.999, P = 0.048). Rs2060793 and rs10741657 were associated with insulin area under the curve (P = 0.028, P = 0.042, respectively), while rs739837 and rs6013897 demonstrated a correlation with fasting glucose (P = 0.019, P = 0.049, respectively). Additionally, rs2248359 displayed an association with leukocyte counts (B = 0.063 P = 0.033) and rs16847024 was related to high-sensitivity C-reactive protein levels (B = 0.086, P = 0.005). Our results indicate an association between GC variants and GDM, as well as a relation between a subset of loci in CYP2R1, CYP24A1, and VDR and clinical parameters related to GDM. Our findings may provide information for identifying biomarkers for early risk prediction of GDM and the pathways involved in disease progression.