Arsenic exposure during pregnancy and postpartum maternal glucose tolerance: evidence from Bangladesh

Background Arsenic exposure has been associated with gestational diabetes mellitus. However, the extent to which arsenic exposure during pregnancy is associated with postpartum glucose intolerance is unknown. Methods We studied 323 women in Bangladesh. We assessed arsenic exposure in early pregnancy via toenail and water samples. We measured fasting glucose and insulin in serum at a mean (SD) of 4.0 (3.5) weeks post-delivery. We ran covariate-adjusted, linear regression models to examine associations of arsenic concentrations with HOMA-IR, a marker of insulin resistance, and HOMA-β, a marker of beta cell function. Results Median (IQR) arsenic concentration was 0.45 (0.67) μg/g in toenails and 2.0 (6.5) μg/L in drinking water. Arsenic concentrations during pregnancy were not associated with insulin resistance or beta cell function postpartum. HOMA-IR was 0.07% (− 3.13, 3.37) higher and HOMA-β was 0.96% (− 3.83, 1.99) lower per IQR increment in toenail arsenic, but effect estimates were small and confidence intervals crossed the null. Conclusions Although arsenic exposure during pregnancy has been consistently associated with gestational diabetes mellitus, we found no clear evidence for an adverse effect on postpartum insulin resistance or beta cell function.

Characteristics of the gut microbiome in women with gestational diabetes mellitus: A systematic review

Background The incidence of women developing gestational diabetes mellitus (GDM) is increasing, which is associated with an increased risk of type 2 diabetes mellitus (T2DM) for both mother and child. Gut microbiota dysbiosis may contribute to the pathogenesis of both GDM and the accompanying risk of T2DM. Thus, a better understanding of the microbial communities associated with GDM could offer a potential target for intervention and treatment in the future. Therefore, we performed a systematic review to investigate if the GDM women have a distinct gut microbiota composition compared to non-GDM women. Methods We identified 21 studies in a systematic literature search of Embase and PubMed up to February 24, 2021. Data on demographics, methodology and identified microbial metrics were extracted. The quality of each study was assessed according to the Newcastle-Ottawa Scale. Results Sixteen of the studies did find a GDM-associated gut microbiota, although no consistency could be seen. Only Collinsella and Blautia showed a tendency to be increased in GDM women, whereas the remaining genera were significantly different in opposing directions. Conclusion Although most of the studies found an association between GDM and gut microbiota dysbiosis, no overall GDM-specific gut microbiota could be identified. All studies in the second trimester found a difference between GDM and non-GDM women, indicating that dysbiosis is present at the time of diagnosis. Nevertheless, it is still unclear when the dysbiosis develops, as no consensus could be seen between the studies investigating the gut microbiota in the first trimester of pregnancy. However, studies varied widely concerning methodology and study design, which might explain the highly heterogeneous gut microbiota compositions between studies. Therefore, future studies need to include multiple time points and consider possible confounding factors such as ethnicity, pre-pregnancy body mass index, and GDM treatment.

The interactive effects of pre-pregnancy body mass index, thyroid function, and blood lipid levels on the risk of gestational diabetes mellitus: a crossover analysis

Background Studies have demonstrated the associations between pre-pregnancy obesity, thyroid dysfunction, dyslipidemia, and increased risk of gestational diabetes mellitus (GDM) in pregnant women. This study was designed to investigate whether and to what extent, the interactions between these factors contribute to the risk of GDM. Methods A case-control study of 232 GDM cases and 696 controls was conducted among pregnant women from Hangzhou, China. Multiple logistic regression analysis was applied to identify independent risk factors of GDM. Crossover analysis was performed to assess the interactive effects of pre-pregnancy body mass index (pBMI), thyroid hormones, blood lipid profiles on the risk of GDM. The indexes including attributable proportion (AP) to the interaction and the relative excess risk due to interaction (RERI) were calculated. Results Chinese pregnant women with pBMI > 23 kg/m2 (adjusted: OR=4.162, P<0.001), high triglyceride levels (> 2.30 mmol/L) (adjusted: OR=1.735, P<0.001) and the free triiodothyronine/free thyroxine (FT3/FT4) ratio ≥0.502 (OR=4.162, P<0.001) have significantly increased risk of GDM. Crossover analysis indicated that there were significant interactions between pre-pregnancy overweight/obesity and FT3/FT4 ≥0.502(AP=0.550, P<0.001; RERI=7.586, P=0.009), high TG levels and FT3/FT4≥0.502 (AP=0.348, 95%CI=0.081~0.614, P=0.010; RERI =2.021, 95%CI=0.064~3.978, P=0.043) on the risk of GDM. Conclusion The interactions between pBMI and FT3/FT4 ratio, TG level, and FT3/FT4 ratio may have significant impacts on the risk of GDM in pregnant women. Such findings may help improve our understanding of the pathogenesis of GDM as well as develop comprehensive strategies for the management of GDM.

The Challenges for Screening and Diagnosing Gestational Diabetes Mellitus in Brazil: a cross-sectional study in a low-risk obstetric hospital.

Background: Gestational Diabetes Mellitus (GDM) is a very prevalent disease and can cause several morbidities for women and their offspring. The literature demonstrates the necessity for a better approach during prenatal assistance to detect and treat the disease. We aimed to evaluate the model and efficacy of GDM screening and diagnosis in a referenced low-risk obstetrical center of the municipality of Assis, Sao Paulo state, Brazil. Moreover, the specific objective was to evaluate the prevalence of GDM. Methods: We conducted a retrospective cross-sectional study of pregnant women, in which 257 prenatal cards and the clinical approaches used for GDM diagnosis and their results. We observed the consecutive patients admitted to the low-risk referenced obstetrical service of the "Santa Casa de Assis-SP" for childbirth from January to August 2021. Results: There were 257 pregnant women, 227 prenatal cards obtained. Of these, 24.6% of the cards were considered incomplete, 25 (9.72%) did not contain the initial fasting plasma glucose information, and 93 (36.18%) did not describe this information in the second to the third trimester. The prevalence of GDM in the population was 14.78%. Conclusion: We observed many pregnant women not screened according to the recommended guidelines and many prenatal cards with incomplete information. According to the screening and diagnosis guidelines, GDM prevalence was underestimated. The lack of prenatal card information and inadequacy of screening and diagnoses were observed in this population.

Dynamic Regulation of Lipid Metabolism in the Placenta of in Vitro and in Vivo Models of Gestational Diabetes Mellitus

Background: The purpose of this study was to investigate lipid metabolism in the placenta of Gestational diabetes mellitus (GDM) individuals and to evaluate its effect on the fetus. Methods: We examined the expression of lipogenesis- and lipolysis-related proteins in the in vitro and in vivo GDM placenta models. Results: The levels of sterol regulatory element binding protein-1c (SREBP-1c) were increased, and fat accumulated more during early hyperglycemia, indicating that lipogenesis was stimulated. When hyperglycemia was further extended, lipolysis was activated due to the phosphorylation of hormone-sensitive lipase (HSL) and expression of adipose triglyceride lipase (ATGL). In the animal model of GDM and in the placenta of GDM patients during the extended stage of GDM, the expression of SREBP-1c decreased and the deposition of fat increased. Similar to the results obtained in the in vitro study, lipolysis was enhanced in the animal and human placenta of extended GDM. Conclusion: These results suggest that fat synthesis may be stimulated by lipogenesis in the placenta when the blood glucose level is high. Subsequently, the accumulated fat can be degraded by lipolysis and more fat and its metabolites can be delivered to the fetus when the GDM condition is extended at the late stage of gestation. Imbalanced fat metabolism in the placenta and fetus of GDM patients can cause metabolic complications in the fetus, including fetal macrosomia, obesity, and type 2 diabetes mellitus.

Gestational Diabetes Mellitus: The Crosslink among Inflammation, Nitroxidative Stress, Intestinal Microbiota and Alternative Therapies

Gestational diabetes mellitus (GDM) is characterized by a set of metabolic complications arising from adaptive failures to the pregnancy period. Estimates point to a prevalence of 3 to 15% of pregnancies. Its etiology includes intrinsic and extrinsic aspects of the progenitress, which may contribute to the pathophysiogenesis of GDM. Recently, researchers have identified that inflammation, oxidative stress, and the gut microbiota participate in the development of the disease, with potentially harmful effects on the health of the maternal-fetal binomial, in the short and long terms. In this context, alternative therapies were investigated from two perspectives: the modulation of the intestinal microbiota, with probiotics and prebiotics, and the use of natural products with antioxidant and anti-inflammatory properties, which may mitigate the endogenous processes of the GDM, favoring the health of the mother and her offspring, and in a future perspective, alleviating this critical public health problem.