Roles of insulin resistance and beta cell dysfunction in macrosomia among Chinese women with gestational diabetes mellitus

Placental IGFBP1 levels during early pregnancy and the risk of insulin resistance and gestational diabetes

Reduced insulin sensitivity (insulin resistance) is a hallmark of normal physiology in late pregnancy and also underlies gestational diabetes mellitus (GDM). We conducted transcriptomic profiling of 434 human placentas and identified a positive association between insulin-like growth factor binding protein 1 gene (IGFBP1) expression in the placenta and insulin sensitivity at ~26 weeks gestation. Circulating IGFBP1 protein levels rose over the course of pregnancy and declined postpartum, which, together with high gene expression levels in our placenta samples, suggests a placental or decidual source. Higher circulating IGFBP1 levels were associated with greater insulin sensitivity (lesser insulin resistance) at ~26 weeks gestation in the same cohort and in two additional pregnancy cohorts. In addition, low circulating IGFBP1 levels in early pregnancy predicted subsequent GDM diagnosis in two cohorts of pregnant women. These results implicate IGFBP1 in the glycemic physiology of pregnancy and suggest a role for placental IGFBP1 deficiency in GDM pathogenesis.

Association of Parity With Insulin Resistance Early in Pregnant Women: ECLIPSES Study

CONTEXT

Little is known about whether parity is associated with elevated early-pregnancy insulin resistance (IR), or whether overweight/obesity contributes to increasing the possible effect.

OBJECTIVE

We determined the associations between parity and glucose metabolism parameters in the first trimester of pregnancy in a Mediterranean pregnant population, and whether these associations are affected by overweight/obesity.

METHODS

A cross-sectional study was conducted of 264 healthy pregnant women from the ECLIPSES study who were recruited at 12 weeks of gestation. At baseline, details on socioeconomic status, obstetric history (including parity, ie, number of births), lifestyle factors, anthropometry, and blood samples were collected. Fasting serum glucose, insulin, and homeostasis model assessment of insulin resistance (HOMA-IR) index were assessed in the first trimester. Elevated IR was defined as the upper HOMA-IR tertile (≥1.58). Multivariable linear regression and Cox regression model with constant time were performed.

RESULTS

Parity ranged from 0 to 4. After multivariable adjustment, the insulin levels (β [% change]: 20.92; 95% CI, 4.08-37.71) and HOMA-IR index (β [% change]: 19.72; 95% CI, 2.43-40.49) were positively associated with parity. Additionally, multiparous women, as compared to nulliparous, were more likely to have higher HOMA-IR levels (primiparous [1 birth], β [% change[: 16.88; 95% CI, -1.00 to 37.99; multiparous [≥2 births), β [% change]: 32.18; 95% CI, 3.56-68.71), and an increased relative risk (RR) of an elevated IR (primiparous [1 birth], RR: 1.55; 95% CI, 1.03-2.36; multiparous (≥2 births), RR: 1.72; 95% CI, 1.05-2.83). The combination of multiparity and overweight/obesity conferred a 3.04-fold increase in the RR of elevated IR, which increased proportionally to the number of parities.

CONCLUSION

This study demonstrates that parity may have a negative effect on early-pregnancy IR and that maternal overweight/obesity appears to further aggravate this relationship.

Evaluation of insulin secretion and insulin sensitivity in pregnant women: Application value of simple indices

The prevalence of gestational diabetes mellitus (GDM) is increasing annually, which poses substantial harm to the health of both mothers and children. Therefore, selection of clinically applicable and easily detectable indicators in the assessment of maternal insulin secretory function and insulin sensitivity in pregnant women undoubtedly holds great importance in evaluating the risk of GDM, guiding the choice of GDM therapy modalities, and improving the ability to provide early warning of adverse pregnancy outcomes. Compared with the classic clamp technique, many simple indices are more suited for use among pregnant women due to the low frequency of blood sampling and simple administration involved. While indices derived from fasting blood glucose and fasting insulin levels are most readily available, they are unable to provide information on the ability of insulin to manage the glucose load during pregnancy. Although the indices derived from the insulin and glucose values at each time point of the oral glucose tolerance test can provide a more comprehensive picture of the insulin sensitivity and insulin secretory function of the body, their application is constrained by the complexity of the procedure and associated high costs. Concomitantly, the findings from different studies are influenced by a variety of confounding factors, such as the gestational age during testing, race, and detection method. Furthermore, insulin secretory function and insulin sensitivity in pregnant women differ from those in non-pregnant women in that they change significantly with prolonged pregnancy; hence, there is an urgent need to develop a pregnancy-specific reference range. This article reviews the progress in the application of simple indices to help clinicians better understand their potential application in detecting GDM.

Refining the diagnosis of gestational diabetes mellitus: a systematic review and meta-analysis

BACKGROUND

Perinatal outcomes vary for women with gestational diabetes mellitus (GDM). The precise factors beyond glycemic status that may refine GDM diagnosis remain unclear. We conducted a systematic review and meta-analysis of potential precision markers for GDM.

METHODS

Systematic literature searches were performed in PubMed and EMBASE from inception to March 2022 for studies comparing perinatal outcomes among women with GDM. We searched for precision markers in the following categories: maternal anthropometrics, clinical/sociocultural factors, non-glycemic biochemical markers, genetics/genomics or other -omics, and fetal biometry. We conducted post-hoc meta-analyses of a subset of studies with data on the association of maternal body mass index (BMI, kg/m2) with offspring macrosomia or large-for-gestational age (LGA).

RESULTS

A total of 5905 titles/abstracts were screened, 775 full-texts reviewed, and 137 studies synthesized. Maternal anthropometrics were the most frequent risk marker. Meta-analysis demonstrated that women with GDM and overweight/obesity vs. GDM with normal range BMI are at higher risk of offspring macrosomia (13 studies [n = 28,763]; odds ratio [OR] 2.65; 95% Confidence Interval [CI] 1.91, 3.68), and LGA (10 studies [n = 20,070]; OR 2.23; 95% CI 2.00, 2.49). Lipids and insulin resistance/secretion indices were the most studied non-glycemic biochemical markers, with increased triglycerides and insulin resistance generally associated with greater risk of offspring macrosomia or LGA. Studies evaluating other markers had inconsistent findings as to whether they could be used as precision markers.

CONCLUSIONS

Maternal overweight/obesity is associated with greater risk of offspring macrosomia or LGA in women with GDM. Pregnancy insulin resistance or hypertriglyceridemia may be useful in GDM risk stratification. Future studies examining non-glycemic biochemical, genetic, other -omic, or sociocultural precision markers among women with GDM are warranted.

Placental RNA sequencing implicates IGFBP1 in insulin sensitivity during pregnancy and in gestational diabetes

Reduced insulin sensitivity (or greater insulin resistance) is a hallmark of normal physiology in late pregnancy and also underlies gestational diabetes mellitus (GDM) pathophysiology. We conducted transcriptomic profiling of 434 human placentas and identified a strong positive association between insulin-like growth factor binding protein 1 gene (IGFBP1) expression in the placenta and insulin sensitivity at ~ 26 weeks' gestation. Circulating IGFBP1 protein levels rose over the course of pregnancy and declined postpartum, which together with high placental gene expression levels, suggests a placental source. Higher circulating IGFBP1 levels were strongly associated with greater insulin sensitivity (lesser insulin resistance) at ~ 26 weeks' gestation in the same cohort and two additional pregnancy cohorts. In addition, low circulating IGFBP1 levels in early pregnancy predicted subsequent GDM diagnosis in two cohorts. These results implicate IGFBP1 in the glycemic physiology of pregnancy and suggest a role for placental IGFBP1 deficiency in GDM pathogenesis.

Glycemic status during pregnancy according to fasting and post-load glucose values: The association with adverse pregnancy outcomes. An observational study

AIM

Prognosis of treated hyperglycemia in pregnancy (HIP) may differ according to whether diagnosis following an oral glucose tolerance test (OGTT) is based on high fasting and/or high post-load glucose values.

METHODS

From a multiethnic prospective study, we included 8,339 women screened for HIP after 22 weeks of gestation. We evaluated the risk of large-for-gestational-age (LGA) infant (primary endpoint) and other adverse pregnancy outcomes according to HIP status in four groups defined as follows: no HIP (n = 6,832, reference); isolated fasting HIP (n = 465), isolated post-load HIP (n = 646), and fasting and post-load HIP (n = 396).

RESULTS

After adjusting for age, body mass index, ethnicity, smoking during pregnancy and parity, compared with no HIP, the adjusted odds ratios [95% confidence interval] for LGA infant were higher in the isolated fasting HIP (1.47 [1.11-1.96]) and fasting and post-load HIP (1.65 [1.23-2.21]) groups, but not in the isolated post-load HIP (1.13 [0.86-1.48]) group. The adjusted odds ratios for preterm delivery and neonatal intensive care unit were higher in the post-load HIP group (1.44 [1.03-2.03] and 1.28 [1.04-1.57], respectively), the fasting and post-load HIP group (1.81 [1.23-2.68] and 1.42 [1.10-1.81], respectively) but not in the isolated fasting HIP group (1.34 [0.90-2.00] and 1.20 [0.94-1.52], respectively).

CONCLUSION

Despite glucose-lowering care and adjustment for confounders, compared with no HIP, fasting HIP was associated with a higher rate of LGA infant, whereas post-load HIP was associated with higher preterm delivery and neonatal intensive care unit admission rates.

Comparison of the key modifiable factors in the first 1000 days predicting subsequent overweight and obesity in pre-school children in Tehran: a case-control study

The identification of paediatric obesity predictors in the early stages of life is warranted, as it can influence the development of effective strategies to prevent metabolic disorders. In this case-control study, we assessed nine risk factors for paediatric obesity, namely a birth weight > 4000 g, an exclusive breast-feeding period < 4 months, the introduction of solid food at < 4 months, maternal overweight or obesity before pregnancy, maternal smoking during pregnancy, the presence of gestational diabetes, paternal overweight and obesity and paternal smoking. In order to identify the most relevant predictors of paediatric obesity, we employed a multiple logistic regression model with R2 Cox Snell by adjusting confounders. In the randomly selected 509 preschool children from Tehran, children exposed to gestational diabetes had the maximum predicted probability of obesity (4·36 (1·94, 9·80) %) among the analysed risk factors %. The introduction of solid food at < 4 months of age increased the risk of obesity by 2·98 (1·77, 4·97 %). The OR of childhood obesity was associated with maternal overweight and obesity (2·72(1·60-4·60) %), maternal smoking (2·21 (1·18, 4·11) %) and excessive gestational weight gain (1·89 (1·23, 2·91) %). Paternal smoking and high birth weight increased the risk of paediatrics obesity > 1·8 times (1·15-2·94) and > 1·5 times (1·015-2·43), respectively. There was no association between the paternal BMI, the exclusive breast-feeding time and the risk of paediatric obesity. Among early risk factors, probably gestational diabetes can be considered as the most important predictor for the risk of paediatric obesity.

Metabolic characteristics and adverse pregnancy outcomes for women with hyperglycaemia in pregnancy as a function of insulin resistance

AIM

Recent studies have shown that women with hyperglycaemia in pregnancy and insulin resistance have a greater risk of adverse pregnancy outcomes than women with normoglycaemic pregnancies. This study aimed to determine adverse pregnancy outcomes of women with hyperglycaemia in pregnancy only as a function of insulin resistance.

METHODS

From a prospective cohort study, we included 1,423 women with hyperglycaemia in pregnancy whose insulin resistance was evaluated using homeostatic model assessment for insulin resistance (HOMA-IR) when care was first provided for this condition. We compared the adverse pregnancy outcomes for different tertiles of HOMA-IR (intertertile range 1.9 and 3.3).

RESULTS

Increasing HOMA-IR tertiles were positively associated with the rate of insulin therapy (tertile 1, 2 and 3: 32.7, 47.0 and 58.7%, P < 0.0001), caesarean section (23.7, 26.0 and 32.2%, respectively, P < 0.01), gestational hypertension (1.3, 2.8 and 5.4% respectively, P < 0.01), preeclampsia (1.5, 2.8 and 4.5% respectively, P < 0.05), large-for-gestational-age infant (13.3, 10.4 and 17.6% respectively, P < 0.05), and neonatal hypoglycaemia (0.8, 1.5 and 3.2% respectively, P < 0.05). Women in the 3^rd HOMA-IR tertile were more likely to have insulin therapy (odds ratio 2.09 (95% interval confidence 1.61-2.71)), hypertensive disorders (2.26 (1.42-3.36)), and large-for-gestational-age infant (1.42 (1.01-1.99)) than those in the 1^st and 2^nd tertiles combined in multivariable logistic regression analyses adjusted for gestational age at HOMA-IR measurement, glycaemic status, age, body mass index, family history of diabetes, parity and ethnicity.

CONCLUSION

Despite suitable care and increased rates of insulin therapy during pregnancy, higher insulin resistance in women with hyperglycaemia in pregnancy was associated with a greater risk of adverse pregnancy outcomes.

Protective Effects of Astragaloside IV on Uric Acid-Induced Pancreatic β-Cell Injury through PI3K/AKT Pathway Activation

Background

Elevated uric acid (UA) has been found to damage pancreatic β-cell, promote oxidative stress, and cause insulin resistance in type 2 diabetes (T2D). Astragaloside IV (AS-IV), a major active monomer extracted from Astragalus membranaceus (Fisch.) Bunge. which belongs to TRIB. Galegeae (Br.) Torrey et Gray, Papilionaceae, exhibits various activities in a pathophysiological environment and has been widely employed to treat diseases. However, the effects of AS-IV on UA-induced pancreatic β-cell damage need to be investigated and the associating mechanism needs to be elucidated. This study was designed to determine the protective effects and underlying mechanism of AS-IV on UA-induced pancreatic β-cell dysfunction in T2D.

Methods

UA-treated Min6 cells were exposed to AS-IV or wortmannin. Thereafter, the 3-(45)-dimethylthiahiazo(-z-y1)-35-di-phenytetrazoliumromide (MTT) assay and flow cytometry were employed to determine the effect of AS-IV on cell proliferation and apoptosis, respectively. Insulin secretion was evaluated using the glucose-stimulated insulin secretion (GSIS) assay. Finally, western blot and quantitative real-time polymerase chain reaction (qRT-PCR) were performed to determine the effect of AS-IV on the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) pathway in UA-treated cells.

Results

AS-IV had no cytotoxic effects on Min6 cells. UA significantly suppressed Min6 cell growth, promoted cell apoptosis, and enhanced caspase-3 activity; however, AS-IV abolished these effects in a dose-dependent manner. Further, decreased insulin secretion was found in UA-treated Min6 cells compared to control cells, and the production of insulin was enhanced by AS-IV in a dose-dependent manner. AS-IV significantly increased phosphorylated (p)-AKT expression and the ratio of p-AKT/AKT in Min6 cells exposed to UA. No evident change in AKT mRNA level was found in the different groups. However, the effects of AS-IV on UA-stimulated Min6 cells were reversed by 100 nM wortmannin.

Conclusion

Collectively, our data suggest that AS-IV protected pancreatic β-cells from UA-treated dysfunction by activating the PI3K/AKT pathway. Such findings suggest that AS-IV may be an efficient natural agent against T2D.

Angiopoietin-Like 8 in Gestational Diabetes Mellitus: Reduced Levels in Third Trimester Maternal Serum and Placenta, Increased Levels in Cord Blood Serum

Gestational diabetes mellitus (GDM) poses a significant health risk to pregnant women, and thus exploring the potential underlying mechanism is highly desirable. The aim of the study was to compare maternal serum, cord blood serum, and placental angiopoietin-like 8 (ANGPTL8) levels in the third trimester of pregnancy in women with and without gestational diabetes and explore the potential underlying mechanism. A total of 42 pregnant women (23 with GDM and 19 with normal glucose tolerance (NGT)) along with 29 age-matched non-pregnant healthy females were enrolled. All pregnant subjects were in the late third trimester. Maternal serum and cord blood serum ANGPTL8 levels were measured with an enzyme-linked immunosorbent assay and the protein levels of ANGPTL8 in placentas were assessed with western blotting. The associations between maternal serum and cord blood serum ANGPTL8 levels and metabolic parameters were investigated with the Spearman correlation analysis. Significantly lower levels of maternal serum and placental ANGPTL8 levels were observed in GDM patients compared to NGT pregnant women, while remarkably higher ANGPTL8 levels were present in the cord blood serum samples. The maternal serum ANGPTL8 level was positively correlated with BMI, total cholesterol, triglycerides, and AUC for OGTT and birthweight. Additionally, the cord blood serum ANGPTL8 level was positively correlated with insulin and the homeostatic model assessment for insulin resistance. Both maternal serum and cord blood serum ANGPTL8 levels seemed to correlate with GDM and has the potential to be used as a biomarker for GDM and birthweight prediction.

Associations between insulin resistance and adverse pregnancy outcomes in women with gestational diabetes mellitus: a retrospective study

Background

This study aimed to explore the relationship between insulin resistance (IR) and adverse pregnancy outcomes in women with gestational diabetes mellitus (GDM), and to determine the risk factors for IR in women with GDM.

Methods

This study employed a retrospective survey of 710 women diagnosed with GDM. Serum lipids, fasting plasma glucose (FPG), glycosylated hemoglobin (HbA1c), and serum protein were measured in the first trimester (6–12 weeks), and OGTT and fasting insulin tests were performed in the second trimester (24–28 weeks). These results were then used to evaluate IR by homeostasis model assessment (HOMA). When HOMA-IR ≥ 2.0, IR was diagnosed. The relationship between HOMA-IR and adverse pregnancy outcomes was analyzed by a logistic regression model, and multiple stepwise regression was used to analyze the risk factors of IR.

Results

IR significantly increasd the risk of the hypertensive disorders of pregnancy and large for gestational age (LGA) (OR = 5.31,95%CI:1.87,15.10; OR = 1.65,95%CI:1.10, 2.48, respectively) in women with GDM, but not for cesarean section, premature delivery, premature rupture of membranes, postpartum hemorrhage, macrosomia and SGA. Compared to normal groups, greater body mass index (BMI) before pregnancy category (overweight or obesity group) were associated with higher risk of IR in the second trimester, the OR (95% CI) were 4.09 (2.65, 6.30) and 6.52 (2.99, 14.20). And higher level of FPG (OR = 1.63, 95%CI: 1.11, 2.40), TG (OR = 1.32, 95%CI: 1.08, 1.63) and weight gain before diagnosis of GDM (OR = 1.08, 95%CI: 1.02, 1.15) were also associated with higher risk of IR in the second trimester in women with GDM, while age (OR = 0.94, 95%CI: 0.90, 0.98)was the weak protective factor for IR.

Conclusion

GDM with IR in the second trimester increased adverse pregnancy outcomes, especially the risk of hypertensive disorders of pregnancy and LGA. In addition, FPG, HbA1c, and TG in early pregnancy, pre-pregnant BMI and weight gain before diagnosis of GDM were all independent risk factors for IR.

A Novel Review of Homocysteine and Pregnancy Complications

Homocysteine (Hct) is a substance produced in the metabolism of methionine. It is an essential type of amino acid gained from the daily diet. Methylenetetrahydrofolate reductase (MTHFR) gene mutation is related to elevated total homocysteine (tHct) expressions, in particular, among women with low folate intake. Hyperhomocysteinemia (HHct) is caused by numerous factors, such as genetic defects, lack of folic acid, vitamin B₆ and B₁₂ deficiency, hypothyroidism, drugs, aging, and renal dysfunction. Increased Hct in peripheral blood may lead to vascular illnesses, coronary artery dysfunction, atherosclerotic changes, and embolic diseases. Compared to nonpregnant women, the Hct level is lower in normal pregnancies. Recent studies have reported that HHct was associated with numerous pregnancy complications, including recurrent pregnancy loss (RPL), preeclampsia (PE), preterm delivery, placental abruption, fetal growth restriction (FGR), and gestational diabetes mellitus (GDM). Besides, it was discovered that neonatal birth weight and maternal Hct levels were negatively correlated. However, a number of these findings lack consistency. In this review, we summarized the metabolic process of Hct in the human body, the levels of Hct in different stages of normal pregnancy reported in previous studies, and the relationship between Hct and pregnancy complications. The work done is helpful for obstetricians to improve the likelihood of a positive outcome during pregnancy complications. Reducing the Hct level with a high dosage of folic acid supplements during the next pregnancy could be helpful for females who have suffered pregnancy complications due to HHct.

Oral L-glutamine rescues fructose-induced poor fetal outcome by preventing placental triglyceride and uric acid accumulation in Wistar rats

BACKGROUND

Metabolic adaptation of pregnant mothers is crucial for placental development and fetal growth/survival. However, evidence exists that indiscriminate consumption of fructose-enriched drink (FED) during pregnancy disrupts maternal-fetal metabolic tolerance with attendant adverse fetal outcomes. Glutamine supplementation (GLN) has been shown to exert a modulatory effect in metabolic disorders. Nevertheless, the effects of GLN on FED-induced poor fetal outcome, and in particular the impacts on placental uric acid/lipid accumulation are unknown. The present study was conducted to test the hypothesis that oral GLN improves fetal outcome by attenuating placental lipid accumulation and uric acid synthesis in pregnant rats exposed to FED.

MATERIALS AND METHODS

Pregnant Wistar rats (160-180 g) were randomly allotted to control, GLN, FED and FED + GLN groups (6 rats/group). The groups received vehicle by oral gavage, glutamine (1 g/kg) by oral gavage, fructose (10%; w/v) and fructose + glutamine, respectively, through gestation.

RESULTS

Data showed that FED during pregnancy caused placental inefficiency, reduced fetal growth, and caused insulin resistance with correspondent increase in fasting blood glucose and plasma insulin. FED also resulted in an increased placental triglyceride, total cholesterol and de novo uric acid synthesis by activating adenosine deaminase and xanthine oxidase activities. Moreover, FED during pregnancy led to increased lipid peroxidation, lactate production with correspondent decreased adenosine and glucose-6-phosphate dehydrogenase-dependent antioxidant defense. These alterations were abrogated by GLN supplementation.

CONCLUSION

These findings implicate that high FED intake during pregnancy causes poor fetal outcome via defective placental uric acid/triglyceride-dependent mechanism. The findings also suggest that oral GLN improves fetal outcome by ameliorating placental defects through suppression of uric acid/triglyceride accumulation.

Expression of miR-409-5p in gestational diabetes mellitus and its relationship with insulin resistance

Expression of miR-409-5p in gestational diabetes mellitus (GDM) and its relationship with insulin resistance were explore. One hundred and forty-nine pregnant women who underwent antenatal examination in Taizhou First People's Hospital were divided into a GDM group and a control group according to whether they had GDM or not. Serum miR-409-5p expression of the two groups was detected, and the levels of glycosylated hemoglobin (HbAlc) and other GDM-related biochemical indicators were measured. Fasting plasma glucose (FPG) was determined by glucose oxidase method, fasting insulin (FINS) was detected by radioimmunoassay, and homeostasis model assessment of insulin resistance (HOMA-IR) was calculated. The relationship between miR-409-5p and other biochemical indicators and insulin resistance was analyzed, and logistic multivariate regression was employed to analyze the risk factors of GDM. miR-409-5p was highly expressed in the serum of GDM patients. HbAlc, FPG, FINS, and HOMA-IR in pregnant women in the GDM group were markedly higher than those in the control group. The serum miR-409-5p in GDM pregnant women showed a positive correlation with HbAlc, FPG, FINS, and HOMA-IR (P<0.05). The insulin resistance group presented remarkably higher serum miR-409-5p level than the non-insulin resistance group. Moreover, it was found that elevated miR-409-5p, FINS, and HOMA-IR were all independent risk factors for the onset of GDM. miR-409-5p is highly expressed in the serum of patients with GDM, and it is positively correlated with insulin resistance index of GDM patients, which may be a potential target for clinical diagnosis and treatment of GDM.

Berberine improves insulin resistance in adipocyte models by regulating the methylation of hypoxia-inducible factor-3α

Methylation of hypoxia-inducible factor-3α (HIF3A) was previously demonstrated to be highly associated with insulin resistance (IR) in patients with gestational diabetes mellitus (GDM). We aimed to study the therapeutic effects of Berberine (BBR) on GDM and the possible mechanisms. The expressions and methylated states of HIF3A in pregnant women with GDM were compared with that in healthy controls. The IR cell models of 3T3-L1 adipocytes was constructed by 1 μmol/l dexamethasone (Dex) and 1 μmol/l insulin (Ins). To evaluate the effects of BBR on IR adipocyte models, cells were subjected to BBR treatment at different concentrations. Transfection of HIF3A siRNA further confirmed the role of HIF3A in the BBR-induced improving effects. Low expression and high methylation of HIF3A gene were frequent in the GDM pregnancies. BBR treatment noticeably increased the glucose usage rates, adiponectin secretion and cell differentiation of IR 3T3-L1 adipocytes. Increased HIF3A expression and decreased methylated state of HIF3A were also found in IR adipocytes. Furthermore, HIF3A silencing not only reversed the effects of BBR on improving insulin sensibility, but also partially abolished the expression alterations of insulin-related genes in IR adipocytes induced by BBR treatment. Our results suggest that BBR improves insulin sensibility in IR adipocyte models, and the improving effects of BBR are possibly realized through the inhibition of HIF3A methylation.

Erythrocyte glucose-6-phosphate dehydrogenase activity and risk of gestational diabetes

Purpose

Glucose-6-phosphate dehydrogenase (G6PD) is the regulating enzyme in the pentose phosphate pathway. A link between the activity of G6PD and diabetes mellitus has previously been reported. The association of G6PD activity with the pathogenesis of gestational diabetes mellitus (GDM) has not yet been investigated. The aim of the present study was to investigate the association of erythrocyte G6PD activity with major characteristics of GDM.

Methods

This case-control study was conducted at Hafez Hospital, Shiraz University of Medical Sciences, Shiraz, Iran from March to November 2017. Eighty-four age-matched pregnant women including GDM (n = 33), impaired glucose tolerance (IGT; n = 7), and normal glucose tolerance (NGT; n = 44) subjects were enrolled in this study. The levels of erythrocyte G6PD activity, fasting plasma glucose (FPG), insulin, malondialdehyde (MDA), and ferric reducing power (FRAP) of serum were measured. The level of homeostasis model for the assessment of insulin resistance (HOMA-IR) was calculated. The data were analyzed using SPSS software. P < 0.05 was considered statistically significant.

Results

The values of FPG, insulin, HOMA-IR, G6PD activity, and FRAP were significantly higher in GDM patients compared to NGT subjects. G6PD activity was correlated with FPG ((r = 0.224; P = 0.041). Binary logistic regression analysis revealed independent association of body mass index >25.88 [OR = 3.23, 95% CI 1.071-9.75, P = 0.037], HOMA- IR >2.33 [OR = 7.15, 95% CI 2.26-22.56, P < 0.001], and G6PD activity>21.17 U/g Hb [OR = 4.63, 95% CI 1.49-14.38, P = 0.008] with an increased risk of GDM. No significant change was observed among serum MDA levels in the three groups.

Conclusion

The findings demonstrate that increased G6PD activity is positively associated with the risk of GDM.

No evidence of attenuation of placental insulin-stimulated Akt phosphorylation and amino acid transport in maternal obesity and gestational diabetes mellitus

Pregnancies complicated by obesity and/or gestational diabetes (GDM) are associated with peripheral insulin resistance; however, the insulin responsiveness of the placenta in these pregnancy complications remains largely unknown. We tested the hypothesis that primary human trophoblast cells and placental villous explants will be insulin responsive, characterized by amino acid transport, Akt and Erk activity with maternal obesity, and/or GDM. We evaluated term placentas from women with normal body mass index (BMI) (normal; n = 15), obesity (OB; n = 11), normal BMI with GDM (N-GDM; n = 11), and obesity with GDM (OB-GDM; n = 11). In a subgroup, primary human trophoblast cells (PHT) were isolated, and in an independent subgroup placental villous explants were exposed to varying concentrations of insulin. Amino acid transport capacity and insulin signaling activity were determined. Insulin significantly increased amino acid transport activity to a similar degree in PHT cells isolated from normal (+21%), N-GDM (+38%), OB (+37%), and OB-GDM (+35%) pregnancies. Insulin increased Akt and Erk phosphorylation in PHT cells (3-fold) and in villous explants (2-fold) in all groups to a similar degree. In contrast to the peripheral maternal insulin resistance commonly associated with obesity and/or GDM, we found that the placenta is insulin sensitive in these pregnancy complications. We suggest that elevated maternal insulin levels in pregnancies complicated by obesity and/or GDM promote critical placental functions, including amino acid transport. Insulin-stimulated placental nutrient delivery may contribute to the increased risk of fetal overgrowth and adiposity in these pregnancies. Moreover, our findings may inform efforts to optimize insulin regimens for women with GDM.

Interactive effects of prepregnancy overweight and gestational diabetes on macrosomia and large for gestational age: A population-based prospective cohort in Tianjin, China

AIMS

Obesity increases risk of gestational diabetes mellitus (GDM) and GDM increases risk of macrosomia but their inter-relations for increased risk of macrosomia remain uncertain. We aimed to examine associations between prepregnancy overweight and macrosomia, and synergistic effects between prepregnancy overweight and GDM on macrosomia.

METHODS

From 2010 to 2012, 19,622 women in urban Tianjin, China, underwent a 50-g 1-h glucose challenge test (GCT) at 24-28 gestational weeks and followed by a 75-g 2-h oral glucose tolerance test (OGTT) if the GCT value was ≥ 7.8 mmol/L. GDM was defined according to International Association of Diabetes and Pregnancy Study Group's criteria. Overweight was defined as body mass index ≥ 24.0 kg/m². Logistic regression was performed to obtain odds ratios (ORs) and 95% confidence intervals (CIs). Additive interaction between prepregnancy overweight and GDM was used to test synergistic effects.

RESULTS

In the cohort, 1791 (9.1%) and 1726 (8.8%) of the women delivered a macrosomic infant or a large-for-gestational-age (LGA) infant, respectively. Prepregnancy overweight was associated with increased risk of macrosomia and LGA with adjusted ORs being 2.29 (95%CI: 2.07-2.54) and 2.27 (2.05-2.52), respectively. Copresence of prepregnancy overweight and GDM greatly enhanced the adjusted ORs of overweight alone (ORs for macrosomia and LGA: 2.17, 1.94-2.42 & 2.21,1.98-2.47) and GDM alone (ORs for macrosomia and LGA: 2.01,1.48-2.72 & 2.14, 1.60-2.87) for macrosomia and LGA to 5.29 (4.07-6.87) for macrosomia and 4.72 (3.66-6.10) for LGA, with significant additive interactions.

CONCLUSIONS

Prepregnancy overweight increased the risks of macrosomia and LGA independently and synergistically with GDM.

Methylation of HIF3A promoter CpG islands contributes to insulin resistance in gestational diabetes mellitus

BACKGROUND

Gestational diabetes mellitus (GDM) is defined as any degree of glucose intolerance during pregnancy, and will lead to high risk of diabetes even after pregnancy. Hypoxia-inducible factor (HIF) family proteins are transcriptional factors that are highly correlated with methylation, which might be involved in the regulation of GDM.

METHODS

Baseline clinical characteristics of the GDM patients and healthy women were analyzed. Omental tissue from GDM patients and control groups were collected and detected for the expression levels of HIF1A, HIF2A, and HIF3A. The CpG islands of HIF3A promoter were predicted by "methprimer" software, and the methylation level of CpG islands was detected by bisulfite sequencing PCR.

RESULTS

HIF3A was downregulated in the omental tissue from GDM patients, whereas HIF1A and HIF2A were not affected. Furthermore, HIF3A expression was positively correlated with levels of estrogen receptor α (ESR1) and solute carrier family 2 member 4 (SLC2A4). Moreover, CpG islands of HIF3A promoter were highly methylated in GDM patients. In addition, methylation level of CpG islands could be upregulated by Estradiol (E2) treatment, since high dose of E2 reduced HIF3A mRNA expression in 3T3-L1 adipocytes.

CONCLUSION

Our findings demonstrate that the expression level of HIF3A, but not HIF1A or HIF2A, is downregulated in GDM patients. The methylation status of HIF3A promoter region is highly correlated with GDM, which could be a novel therapeutic target for GDM treatment.