Multi-type maternal diabetes mellitus affects human placental villous geometric morphology: A three-dimensional imaging study.

INTRODUCTION: Diabetes mellitus leads to maldevelopment of the villous morphology in the human placenta, disrupting the exchange of materials between the maternal and fetal compartments, consequently compromising fetal development. This study aims to explore how different types of diabetes mellitus affect human placental villous geometric morphology including branching numbers and sizes (length, diameter). METHODS: Here an optical coherence tomography (OCT)-based 3D imaging platform was utilized to capture 3D images of placental villi from different types of diabetes, including type 1 diabetes mellitus (T1DM), type 2 diabetes mellitus (T2DM), and gestational diabetes mellitus (GDM). RESULTS: Different types of diabetes mellitus exhibit different effects on human placental villous geometric morphological parameters: GDM had greater placenta villous parameters at intermediate villous diameter (IVD), terminal villous diameter (TVD), terminal villous length (TVL) compared to the healthy, T1DM, and T2DM, and these differences were statistically significant. The TVD of T1DM and T2DM had significantly greater sizes than the healthy. There was no statistically significant difference in the number of villous branches among the three types of diabetes, but T1DM and GDM had more villous branches than healthy individuals. DISCUSSION: Diabetes mellitus affects the geometric morphology of human placental villi, with varying effects observed in pregnancies of different diabetes types. These findings offer a novel avenue for exploring underlying pathophysiological mechanisms and enhancing the management of women with diabetes from preconception through pregnancy.

MiR-322-5p is involved in regulating chondrocyte proliferation and differentiation in offspring's growth plate of maternal gestational diabetes.

Pregestational diabetes mellitus (PGDM) has an impact on fetal bone formation, but the underlying mechanism is still obscure. Although miRNAs have been extensively investigated throughout bone formation, their effects on fetal bone development caused by PGDM still need clarification. This study intends to examine the mechanism by which hyperglycemia impairs the bone formation of offspring via miR-322-5p (miR-322). In this study, miR-322 was selected by systemically screening utilizing bioinformatics and subsequent validation experiments. Using streptozotocin (STZ)-induced diabetic mice and ATDC5 cell lines, we found that miR-322 was abundantly expressed in the proliferative and hypertrophic zones of the growth plate, and its expression pattern was disturbed in the presence of hyperglycemia, suggesting that miR-322 is involved in the chondrocyte proliferation and differentiation in absence/presence of hyperglycemia. This observation was proved by manipulating miR-322 expression in ATDC5 cells by transfecting mimic and inhibitor of miR-322. Furthermore, Adamts5, Col12a1, and Cbx6 were identified as the potential target genes of miR-322, verified by the co-transfection of miR-322 inhibitor and the siRNAs, respectively. The evaluation criteria are the chondrocyte proliferation and differentiation and their relevant key gene expressions (proliferation: Sox9 and PthIh; differentiation: Runx2 and Col10a1) after manipulating the gene expressions in ATDC5 cells. This study revealed the regulative role miR-322 on chondrocyte proliferation and differentiation of growth plate by targeting Adamts5, Col12a1, and Cbx6 in hyperglycemia during pregnancy. This translational potential represents a promising avenue for advancing our understanding of bone-related complications in diabetic pregnancy and mitigating bone deficiencies in diabetic pregnant individuals, improving maternal and fetal outcomes.

[The association between visceral adipose thickness and gestational diabetes mellitus in the first trimester].

Objective: To investigate the association between visceral adipose tissue (VAT) thickness in early pregnancy and the risk of gestational diabetes mellitus (GDM). Methods: Based on the Qingdao Women and Children Health Cohort, pregnant women in the first trimester (11-13+6 weeks of gestation) were enrolled in this cohort study between May 2019 and October 2022. The VAT was measured in first trimester and determined as the distance from the inner margin of the rectus abdominis muscle to the anterior wall of the great artery using multi-functional color ultrasound. The 75 g oral glucose tolerance test (OGTT) results were followed up at 24-28 weeks and the participants were divided into GDM group and non-GDM group. The pregnant women were divided into 4 groups according to the VAT quartile. Log-binomial model and linear regression model were used to analyze the association between VAT and GDM/blood glucose. Results: A total of 3 686 pregnant women were included in this study, the mean age of participants was (30.56±4.05) years and 722 were diagnosed with GDM, with an incidence of 19.6%. The log-binomial regression model results showed that compared with VAT thickness Q1 (VAT<14.70 mm), the GDM risk in Q3 (21.65≤VAT≤29.69 mm) and Q4 (VAT ≥29.70 mm) increased by 34% [RR(95%CI): 1.34 (1.08-1.67)], and 61% [RR(95%CI): 1.61 (1.30-2.00)], respectively. Among women with gestational age<35 years old, compared with VAT thickness Q1, the risk of GDM increased by 42% in Q3 [RR(95%CI): 1.42 (1.22-1.65)] and 70% [RR(95%CI): 1.70 (1.46-1.98)] in Q4, whereas no associations were found in women with gestational age ≥35 years old (P>0.05). The association between VAT and GDM risk was only found in pregnant women with pre-pregnancy BMI <24.0 kg/m2, and the GDM risk increased by 57% [RR(95%CI): 1.57 (1.22-2.04)] in Q3 and 65% [RR(95%CI): 1.65 (1.24-2.19)] in Q4 compare with Q1. The results of multiple linear regression analysis showed that VAT was positively correlated with fasting blood glucose, 1-hour blood glucose after 75 g OGTT and 2-hours blood glucose after 75 g OGTT (all Pfor trend<0.001). Conclusion: High VAT thickness in early pregnancy is an independent risk factor for GDM, and the GDM risk increases with the raising of VAT depth.

Excessive palmitic acid disturbs macrophage α-ketoglutarate/succinate metabolism and causes adipose tissue insulin resistance associated with gestational diabetes mellitus.

Abnormal polarization of adipose tissue macrophages (ATMs) results in low-grade systemic inflammation and insulin resistance (IR), potentially contributing to the development of diabetes. However, the underlying mechanisms that regulate the polarization of ATMs associated with gestational diabetes mellitus (GDM) remain unclear. Thus, we aimed to determine the effects of abnormal fatty acids on macrophage polarization and development of insulin resistance in GDM. Levels of fatty acids and inflammation were assessed in the serum samples and adipose tissues of patients with GDM. An in vitro cell model treated with palmitic acid was established, and the mechanisms of palmitic acid in regulating macrophage polarization was clarified. The effects of excessive palmitic acid on the regulation of histone methylations and IR were also explored in the high-fat diet induced GDM mice model. We found that pregnancies with GDM were associated with increased levels of serum fatty acids, and inflammation and IR in adipose tissues. Increased palmitic acid could induce mitochondrial dysfunction and excessive ROS levels in macrophages, leading to abnormal cytoplasmic and nuclear metabolism of succinate and α-ketoglutarate (αKG). Specifically, a decreased nuclear αKG/succinate ratio could attenuate the enrichment of H3K27me3 at the promoters of pro-inflammatory cytokines, such as IL-1ß, IL-6, and TNF-α, leading to cytokine secretion. Importantly, GDM mice treated with GSK-J4, an inhibitor of histone lysine demethylase, were protected from abnormal pro-inflammatory macrophage polarization and excessive production of pro-inflammatory cytokines. Our findings highlight the importance of the metabolism of αKG and succinate as transcriptional modulators in regulating the polarization of ATMs and the insulin sensitivity of adipose tissue, ensuring a normal pregnancy. This novel insight sheds new light on gestational fatty acid metabolism and epigenetic alterations associated with GDM.

Kisspeptin signalling and its correlation with placental ultrastructure and clinical outcomes in pregnant South African women with obesity and gestational diabetes.

INTRODUCTION: Gestational diabetes mellitus (GDM) is a major pregnancy metabolic disorder and is strongly linked with obesity. Kisspeptin is a hormone that increases several thousand-fold in the maternal circulation during human pregnancy, with placenta as its main source. Studies have suggested that kisspeptin regulates trophoblast invasion and promotes pancreatic insulin secretion and peripheral insulin sensitivity. METHODS: In a well-characterized cohort of pregnant South African women and molecular and histological techniques, this study explored the impact and interaction of maternal obesity and GDM on kisspeptin (KISS1) signalling in relation to placental morphology and maternal and neonatal parameters. RESULTS: We found that GDM had no effect on placental KISS1 and KISS1R (KISS1 receptor) mRNA and/or protein expression. However, obesity reduced placental KISS1R mRNA expression even though overall KISS1 protein abundance or localization was not different from the non-obese group. Maternal and cord circulating KISS1 concentrations did not vary with obesity or GDM, but maternal circulating KISS1 was positively correlated with placenta weight in non-GDM obese women, and negatively correlated with placental intervillous space volume in non-GDM non-obese women. Cord serum KISS1 was positively correlated with infant weight in GDM obese women, but negatively correlated with maternal BMI in the non-obese GDM group. Placental syncytiotrophoblast extracellular vesicles exhibited detectable KISS1 and its abundance was ∼50 % lower in those from obese GDM compared to non-GDM women. DISCUSSION: This study shows maternal obesity and GDM can modulate placental kisspeptin signalling and placental morphological development with potential pathophysiological implications for clinically-relevant pregnancy and perinatal outcomes.

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

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

Improved neonatal outcomes in pregnancies with coexisting gestational diabetes and preeclampsia in normal birthweight neonates- insights from a retrospective cohort study.

INTRODUCTION: We aimed to assess neonatal and maternal outcomes in appropriate-for-gestational-weight (AGA) neonates of mothers with both gestational diabetes mellitus (GDM) and preeclampsia (PET). METHODS: Medical records of women diagnosed with GDM or PET were reviewed. Women with AGA neonates were divided into three groups- GDM, PET, and GDM + PET and maternal neonatal and placental outcomes were compared. The primary outcome was a composite of adverse neonatal outcomes, including intensive care unit admission (NICU), neurological morbidity, hypoglycemia, ventilation, respiratory distress syndrome (RDS), phototherapy, sepsis, blood transfusion, and neonatal death. Post-hoc analysis was performed to determine between-group significance. RESULTS: Composite adverse neonatal outcomes are significantly lower in women with multiple morbidities compared to women with confined PET (p = 0.015), and a similar trend is observed when comparing neonatal outcomes between women with GDM to those with GDM + PET, yet these results are underpowered (18.9 % vs. 12.8 % respectively, p = 0.243). Placentas of women with GDM + PET were larger, with a lower rate of placentas below the 10th percentile as compared to placentas of women with isolated PET (p < 0.001), but with similar rates of MVM lesions. DISCUSSION: While maternal and placental outcomes in patients of the GDM + PET group resemble the characteristics of the PET group, surprisingly, the neonatal outcomes in this group are significantly better compared to isolated morbidities. The paradoxical benefit attributed to the coexistence of GDM + PET may be explained by a balance of the opposing trends characterizing these morbidities-the reduced blood and nutrient supply characterizing PET vs. chronic overflow and abundance typical of GDM. CLINICAL TRIAL REGISTRATION: approval of local ethics committee WOMC-19-0152.

Insulin signaling and mitochondrial phenotype of skeletal muscle are programmed in utero by maternal diabetes.

Maternal diabetes may influence glucose metabolism in adult offspring, an area with limited research on underlying mechanisms. Our study explored the impact of maternal hyperglycemia during pregnancy on insulin resistance development. Adult female Sprague-Dawley rats from control and diabetic mothers were mated, and their female offspring were monitored for 150 days. The rats were euthanized for blood and muscle samples. Maternal diabetes led to heightened insulin levels, increased HOMA-IR, elevated triglycerides, and a raised TyG index in adult offspring. Muscle samples showed a decreased protein expression of AMPK, PI3K, MAPK, DRP1, and MFF. These changes induced intergenerational metabolic programming in female pups, resulting in insulin resistance, dyslipidemia, and glucose intolerance by day 150. Findings highlight the offspring's adaptation to maternal hyperglycemia, involving insulin resistance, metabolic alterations, the downregulation of insulin signaling sensors, and disturbed mitochondrial morphology. Maintaining maternal glycemic control emerges as crucial in mitigating diabetes-associated disorders in adult offspring.

Non-hypertensive gestational diabetes mellitus: Placental histomorphology and its association with perinatal outcomes.

INTRODUCTION: Gestational diabetes mellitus (GDM) exerts a great impact on the placenta and reflects changes on placentas both morphological and functionally. The aims of this study are to evaluate the prevalence of placental histopathological lesions in pregnancies complicated by GDM compared to gestational age-matched controls, and their association with maternal and fetal complications. METHODS: Fifty-four singleton GDM-complicated pregnancies were recruited and compared to 33 consecutive normal pregnancies. Two pathologists, blinded to all clinical data, reviewed and evaluated all histological samples of the placentas in accordance with Amsterdam criteria. Relevant demographic, clinical data and primary birth outcomes were recorded. RESULTS: A myriad of histomorphological abnormalities, including chronic inflammation (n = 9/54, p = 0.031), histological chorioamnionitis (n = 23/54, p < 0.001), umbilical/chorionic vasculitis (n = 9/54, p = 0.031), changes related to maternal vascular malperfusion (n = 22/54, p = 0.003), chorangiosis (n = 10/54, p = 0.046) and villous dysmaturity (n = 9/54, p = 0.012) were observed more frequently in the GDM placentas compared to the controls. Additionally, GDM significantly increased the risk of fetal complications, including macrosomia/fetal growth restriction (n = 13/54, p = 0.004). DISCUSSION: Histoarchitectural abnormalities were observed more frequently in placentas of GDM pregnancies compared to the controls. Our findings support the hypothesis that diabetic-induced damage in the placental function may be associated with the increased in fetal growth disorders in GDM-complicated pregnancies.

Lachnospiraceae-derived butyrate mediates protection of high fermentable fiber against placental inflammation in gestational diabetes mellitus.

Inflammation-associated insulin resistance is a key trigger of gestational diabetes mellitus (GDM), but the underlying mechanisms and effective interventions remain unclear. Here, we report the association of placental inflammation (tumor necrosis factor-α) and abnormal maternal glucose metabolism in patients with GDM, and a high fermentable dietary fiber (HFDF; konjac) could reduce GDM development through gut flora-short-chain fatty acid-placental inflammation axis in GDM mouse model. Mechanistically, HFDF increases abundances of Lachnospiraceae and butyrate, reduces placental-derived inflammation by enhancing gut barrier and inhibiting the transfer of bacterial-derived lipopolysaccharide, and ultimately resists high-fat diet-induced insulin resistance. Lachnospiraceae and butyrate have similar anti-GDM and anti-placental inflammation effects, and they can ameliorate placental function and pregnancy outcome effects probably by dampening placental immune dysfunction. These findings demonstrate the involvement of important placental inflammation-related mechanisms in the progression of GDM and the great potential of HFDFs to reduce susceptibility to GDM through gut-flora-placenta axis.

Placenta-derived exosomal miR-135a-5p promotes gestational diabetes mellitus pathogenesis by activating PI3K/AKT signalling pathway via SIRT1.

Most people are aware of gestational diabetes mellitus (GDM), a dangerous pregnancy complication in which pregnant women who have never been diagnosed with diabetes develop chronic hyperglycaemia. Exosomal microRNA (miRNA) dysregulation has been shown to be a key player in the pathophysiology of GDM. In this study, we looked into how placental exosomes and their miRNAs may contribute to GDM. When compared to exosomes from healthy pregnant women, it was discovered that miR-135a-5p was elevated in placenta-derived exosomes that were isolated from the maternal peripheral plasma of GDM women. Additionally, we discovered that miR-135a-5p encouraged HTR-8/SVneo cell growth, invasion and migration. Further research revealed that miR-135a-5p activates HTR-8/SVneo cells' proliferation, invasion and migration by promoting PI3K/AKT pathway activity via Sirtuin 1 (SIRT1). The transfer of exosomal miR-135a-5p generated from the placenta could be viewed as a promising agent for targeting genes and pertinent pathways involved in GDM, according to our findings.

Microstructural Brain Development and Neurodevelopmental Outcome of Very Preterm Infants of Mothers with Gestational Diabetes Mellitus.

INTRODUCTION: There are data linking gestational diabetes mellitus (GDM) with adverse neurodevelopmental outcome in the offspring. We investigated the effect of GDM on microstructural brain development and neurodevelopmental outcome of very preterm infants. MATERIALS AND METHODS: Preterm infants <32 gestational weeks of mothers with GDM obtained cerebral magnetic resonance imaging (MRI) including diffusion-tensor imaging at term-equivalent age. For every infant, two gestational age-, sex-, and MRI scanner type-matched controls were included. Brain injury was assessed and fractional anisotropy (FA) and apparent diffusion coefficient (ADC) measured in 14 defined cerebral regions. Neurodevelopmental outcome was quantified at the corrected age of 24 months using the Bayley Scales of Infant Development. RESULTS: We included 47 infants of mothers with GDM and 94 controls. There were no differences in neonatal morbidity between the groups, nor in any type of brain injury. The GDM group showed significantly higher FA values in the centrum semiovale, the posterior limb of the internal capsule and the pons bilaterally, in the corpus callosum and the right occipital white matter, as well as lower ADC values in the right centrum semiovale, the right occipital white matter and the corpus callosum. Neurodevelopmental outcome did not differ between the groups. CONCLUSION: We found no impairment of brain development in GDM-exposed infants compared to matched controls, but differences in white matter microstructure in specific regions indicating an enhanced maturation. However, neurodevelopmental outcome was equal in both groups. Further studies are needed to better understand brain maturation in preterm infants exposed to GDM.

Adropin as a potential protective factor of metabolic complications in obese pregnant women with hyperglycaemia diagnosed in early pregnancy.

Adropin is a hormone which increases insulin sensitivity. It enhances the oxygenation of glucose in the muscles. The 91 obese pregnant women (BMI >30 kg/m2) with gestational diabetes mellitus (GDM) diagnosed in the first half of pregnancy has been recruited to the study group. The control group consisted of 10 age matched and homogeneous pregnant women with BMI <25 kg/m2. Blood samples were collected on visit V1 - between the 28th and 32nd week and on visit V2 - between the 37th and 39th week of gestation. The ELISA test was used to measure the adropin level. The results in the study group and the control group were compared. Blood samples were collected at the same visits. The median concentration of adropin was 442.2 pg/ml on V1 and 453.1 pg/ml on V2. The increase was significant (p<0.05). Results were significantly lower in the control group's patients, i.e. 57.0 pg/ml (p<0.001) on V1 and 107.9 pg/ml on V2 (p<0.001). The higher adropin level on the V1 and V2 visits were related to patients' lower BMI and better metabolic control. The increase in the adropin level in the third trimester may have been involved in the weight gain reduction, whereas better dietary adherence might have had a compensatory effect on increasing insulin resistance. However, the small control group is a limitation of this study.

High TXNIP expression accelerates the migration and invasion of the GDM placenta trophoblast.

INTRODUCTION: Our previous study has proofed the glucose sensitive gene-thioredoxin-interacting protein (TXNIP) expression was up in the placenta of the patients with gestational diabetes mellitus (GDM), but the pathological mechanisms underlying abnormal TXNIP expression in the placenta of patients with GDM is completely unclear and additional investigations are required to explain the findings we have observed. In the present study, we simulated the high TXNIP expression via introducing the Tet-On "switch" in vitro, approximate to its expression level in the real world, to explore the following consequence of the abnormal TXNIP. METHODS: The expression and localization of TXNIP in the placenta of GDM patients and the health control was investigated via immunofluorescent staining, western blot and RT-qPCR. Overexpression of TXNIP was achieved through transfecting Tet-on system to the human trophoblastic cell line-HTR-8/Svneo cell. TXNIP knockout was obtained via CRISPR-Cas9 method. The cell phenotype was observed via IncuCyte Imaging System and flow cytometry. The mechanism was explored via western blot and RT-qPCR. RESULTS: The expression level of TXNIP in the GDM placenta was nearly 2-3 times higher than that in the control. The TXNIP located at trophoblastic cells of the placenta. When the expression of TXNIP was upregulated, the migration and invasion of the cells accelerated, but cell apoptosis and proliferation did not changed compared with the control group. Furthermore, the size of the TetTXNIP cells became larger, and the expression level of Vimentin and p-STAT3 increased in the TetTXNIP cells. All the changes mentioned above were opposite in the TXNIP-KO cells. CONCLUSIONS: Abnormal expression of TXNIP might be related to the impairment of the GDM placental function, affecting the migration and invasion of the placental trophoblast cells through STAT3 and Vimentin related pathway; thus, TXNIP might be the potential therapeutic target for repairing the placental dysfunction deficient in GDM patients.

Transient elastography and controlled attenuation parameter to evaluate hepatic steatosis and liver stiffness in postpartum patients.

INTRODUCTION: Nonalcoholic fatty liver disease (NAFLD) affects 30% of adults in the United States. Transient elastography (TE) (Fibroscan, Echosens, Paris, France) with controlled attenuation parameter (CAP) is a noninvasive way to evaluate liver steatosis and liver stiffness. The primary objective of this study was to assess prevalence of elevated liver stiffness and steatosis immediately postpartum. Furthermore, we sought to evaluate whether there were differences in rates of metabolic disorders of pregnancy (gestational diabetes mellitus (GDM), gestational hypertension, and preeclampsia) and pre-pregnancy conditions (type 2 diabetes mellitus (DM), chronic hypertension, and obesity) in those with elevated postpartum liver steatosis/liver stiffness. METHODS: IRB approved prospective cross-sectional study in which TE and liver function tests were performed 1-2 days postpartum. CAP ≥300 dB/m was classified as significant steatosis. Increased liver stiffness was defined as ≥7 kPa. Prevalence was determined by proportion of individuals undergoing TE/CAP who met criteria. Chi-square analysis was used to compare differences between groups. RESULTS: Eighty-nine patients were included: 20 (22%) had GDM, 13 (15%) had gestational hypertension, and 15 (17%) had preeclampsia. Women with kPa ≥7 were more likely to have ALT ≥25, type 2 diabetes, and preeclampsia (p < .05). Pre-gravid BMI, BMI at delivery, and GDM were not associated with increased kPa. Pregravid BMI ≥25 and chronic hypertension were associated with CAP ≥ 300 dB/m (p < .05). GDM, preeclampsia, and gestational hypertension were not associated with CAP ≥300 dB/m. CONCLUSIONS: Patients with preeclampsia, type 2 diabetes, and elevated ALT were more likely to have elevated postpartum liver stiffness. Pregravid BMI ≥25 and ≥30 were associated with increased liver steatosis, although did not impact liver stiffness. GDM was not associated with increased liver stiffness or steatosis. Consideration should be made for screening pregnant patients with preeclampsia, type 2 DM and overweight or obese BMI for liver disease in the postpartum period with potential for lifestyle intervention.

Platelets and endothelial dysfunction in gestational diabetes mellitus.

The prevalence of gestational diabetes mellitus (GDM) has increased in recent years, along with the higher prevalence of obesity in women of reproductive age. GDM is a pathology associated with vascular dysfunction in the fetoplacental unit. GDM-associated endothelial dysfunction alters the transfer of nutrients to the foetus affecting newborns and pregnant women. Various mechanisms for this vascular dysfunction have been proposed, of which the most studied are metabolic alterations of the vascular endothelium. However, different cell types are involved in GDM-associated endothelial dysfunction, including platelets. Platelets are small, enucleated cell fragments that actively take part in blood haemostasis and thrombus formation. Thus, they play crucial roles in pathologies coursing with endothelial dysfunction, such as atherosclerosis, cardiovascular diseases, and diabetes mellitus. Nevertheless, platelet function in GDM is understudied. Several reports show a potential relationship between platelet volume and mass with GDM; however, platelet roles and signaling mechanisms in GDM-associated endothelial dysfunction are unclear. This review summarizes the reported findings and proposes a link among altered amount, volume, mass, reactivity, and function of platelets and placenta development, resulting in fetoplacental vascular dysfunction in GDM.

Beta-cell compensation and gestational diabetes.

Gestational diabetes mellitus (GDM) is characterized by glucose intolerance in pregnant women without a previous diagnosis of diabetes. While the etiology of GDM remains elusive, the close association of GDM with increased maternal adiposity and advanced gestational age implicates insulin resistance as a culpable factor for the pathogenesis of GDM. Pregnancy is accompanied by the physiological induction of insulin resistance in the mother secondary to maternal weight gain. This effect serves to spare blood glucose for the fetus. To overcome insulin resistance, maternal ß-cells are conditioned to release more insulin into the blood. Such an adaptive response, termed ß-cell compensation, is essential for maintaining normal maternal metabolism. ß-cell compensation culminates in the expansion of ß-cell mass and augmentation of ß-cell function, accounting for increased insulin synthesis and secretion. As a result, a vast majority of mothers are protected from developing GDM during pregnancy. In at-risk pregnant women, ß-cells fail to compensate for maternal insulin resistance, contributing to insulin insufficiency and GDM. However, gestational ß-cell compensation ensues in early pregnancy, prior to the establishment of insulin resistance in late pregnancy. How ß-cells compensate for pregnancy and what causes ß-cell failure in GDM are subjects of investigation. In this mini-review, we will provide clinical and preclinical evidence that ß-cell compensation is pivotal for overriding maternal insulin resistance to protect against GDM. We will highlight key molecules whose functions are critical for integrating gestational hormones to ß-cell compensation for pregnancy. We will provide mechanistic insights into ß-cell decompensation in the etiology of GDM.

Associations of gestational diabetes and proton density fat fraction of vertebral bone marrow and paraspinal musculature in premenopausal women.

Background and objective: Fat content in bones and muscles, quantified by magnetic resonance imaging (MRI) as a proton density fat fraction (PDFF) value, is an emerging non-invasive biomarker. PDFF has been proposed to indicate bone and metabolic health among postmenopausal women. Premenopausal women with a history of gestational diabetes (GDM) carry an increased risk of developing type 2 diabetes and an increased risk of fractures. However, no studies have investigated the associations between a history of GDM and PDFF of bone or of paraspinal musculature (PSM), composed of autochthonous muscle (AM) and psoas muscle, which are responsible for moving and stabilizing the spine. This study aims to investigate whether PDFF of vertebral bone marrow and of PSM are associated with a history of GDM in premenopausal women. Methods: A total of 37 women (mean age 36.3 ± 3.8 years) who were 6 to 15 months postpartum with (n=19) and without (n=18) a history of GDM underwent whole-body 3T MRI, including a chemical shift encoding-based water-fat separation. The PDFF maps were calculated for the vertebral bodies and PSM. The cross-sectional area (CSA) of PSM was obtained. Associations between a history of GDM and PDFF were assessed using multivariable linear and logistic regression models. Results: The PDFF of the vertebral bodies was significantly higher in women with a history of GDM (GDM group) than in women without (thoracic: median 41.55 (interquartile range 32.21-49.48)% vs. 31.75 (30.03-34.97)%; p=0.02, lumbar: 47.84 (39.19-57.58)% vs. 36.93 (33.36-41.31)%; p=0.02). The results remained significant after adjustment for age and body mass index (BMI) (p=0.01-0.02). The receiver operating characteristic curves showed optimal thoracic and lumbar vertebral PDFF cutoffs at 38.10% and 44.18%, respectively, to differentiate GDM (AUC 0.72 and 0.73, respectively, sensitivity 0.58, specificity 0.89). The PDFF of the AM was significantly higher in the GDM group (12.99 (12.18-15.90)% vs. 10.83 (9.39-14.71)%; p=0.04) without adjustments, while the CSA was similar between the groups (p=0.34). Conclusion: A history of GDM is significantly associated with a higher PDFF of the vertebral bone marrow, independent of age and BMI. This statistical association between GDM and increased PDFF highlights vertebral bone marrow PDFF as a potential biomarker for the assessment of bone health in premenopausal women at risk of diabetes.

Maternal obesity and placental pathology in correlation with adverse pregnancy outcome.

Maternal obesity is associated with increased maternal and fetal morbidity and mortality, with an increased risk of gestational diabetes mellitus (GDM) and preeclampsia (PE). This prospective study histopathologically analyzes the placentas obtained from 34 pregnant obese women studied between October 2016 and May 2020. The 10 cases of term placentas from obese pregnancies with GDM and the 12 cases with PE were examined by the Hematoxylin-Eosin (HE), Masson's trichrome (MT) and Periodic Acid-Schiff-Hematoxylin (PAS-H) classical stainings, and by the immunohistochemical evaluation and compared to placentae from uncomplicated term obese pregnancies (12 cases). We did not meet placental histopathological (HP) abnormalities that we could classify as characteristic only for the state of obese pregnancy, but we did find placental changes associated with PE and GDM, in the context of obese pregnancy. In the case of association with PE, there were common lesions, manifested by intra- and perivillous fibrinoid deposition, calcification, and placental infarction area, to which were added numerous syncytial knots. In the case of obese pregnancy associated with GDM, we found, in addition to common placental lesions of obesity, intravillositary vascular edema and in the terminal villi appearing chorangiosis. This study revealed a number of HP changes that occur in maternal obesity, even in uncomplicated obese pregnancies. A characteristic of obese pregnancies associated with PE was the presence of numerous syncytial knots, and in obese pregnancies associated with GDM, the most common HP lesion was placental chorangiosis. Certainly, we cannot conclude that these HP lesions are specific to a particular pathology, but they belong primarily to the status of maternal obesity.

Abnormal placental villous maturity and dysregulated glucose metabolism: implications for stillbirth prevention.

OBJECTIVES: In the UK one in 250 pregnancies end in stillbirth. Abnormal placental villous maturation, commonly associated with gestational diabetes, is a risk factor for stillbirth. Histopathology reports of placental distal villous immaturity (DVI) are reported disproportionately in placentas from otherwise unexplained stillbirths in women without formal diagnosis of diabetes but with either clinical characteristics or risk factors for diabetes. This study aims to establish maternal factors associated with DVI in relation to stillbirth. METHODS: Placental histopathology reports were reviewed for all pregnant women delivering at University College London Hospital between July 2018 to March 2020. Maternal characteristics and birth outcomes of those with DVI were compared to those with other placental lesions or abnormal villous maturation. RESULTS: Of the 752 placental histopathology reports reviewed, 11 (1.5%) were reported as diagnostic of DVI. Eighty cases were sampled for clinical record analysis. All women with DVI had normal PAPP-A (>0.4 MoM), normal uterine artery Doppler studies (UtA-PI) and were normotensive throughout pregnancy. Nearly one in five babies (2/11, 18.5%) with DVI were stillborn and 70% had at least one high glucose test result in pregnancy despite no formal diagnosis of diabetes. CONCLUSIONS: These findings suggest that the mechanism underlying stillbirth in DVI likely relates to glucose dysmetabolism, not sufficient for diagnosis using current criteria for gestational diabetes, resulting in placental dysfunction that is not identifiable before the third trimester. Relying on conventional diabetes tests, foetal macrosomia or growth restriction, may not identify all pregnancies at risk of adverse outcomes from glucose dysmetabolism.