Effects of gestational diabetes on fetal oxygen and glucose levels in vivo

Bone development in fetuses with intrauterine growth restriction caused by maternal endocrine-metabolic dysfunctions

Intrauterine growth restriction (IUGR) affects a large proportion of infants, particularly in underdeveloped countries. Among the main causes of IUGR, maternal endocrine-metabolic dysfunction is highlighted, either due to its high incidence or due to the severity of the immediate and mediated changes that these dysfunctions cause in the fetus and the mother. Although the effects of endocrine and metabolic disorders have been widely researched, there are still no reviews that bring together and summarize the effects of these conditions on bone development in cases of IUGR. Therefore, the present literature review was conducted with the aim of discussing bone changes observed in fetuses with IUGR caused by maternal endocrine-metabolic dysfunction. The main endocrine dysfunctions that occur with IUGR include maternal hyperthyroidism, hypothyroidism, and hypoparathyroidism. Diabetes mellitus, hypertensive disorders, and obesity are the most important maternal metabolic dysfunctions that compromise fetal growth. The bone changes reported in the fetus are, for the most part, due to damage to cell proliferation and differentiation, as well as failures in the synthesis and mineralization of the extracellular matrix, which results in shortening and fragility of the bones. Some maternal dysfunctions, such as hyperthyroidism, have been widely studied, whereas conditions such as hypoparathyroidism and gestational hypertensive disorders require further study regarding the mechanisms underlying the development of bone changes. Similarly, there is a gap in the literature regarding changes related to intramembranous ossification, as most published articles only describe changes in endochondral bone formation associated with IUGR. Furthermore, there is a need for more research aimed at elucidating the late postnatal changes that occur in the skeletons of individuals affected by IUGR and their possible relationships with adult diseases, such as osteoarthritis and osteoporosis.

Gestational diabetes mellitus and development of intergenerational non-alcoholic fatty liver disease (NAFLD) after delivery: a systematic review and meta-analysis

Background

It is known that gestational diabetes mellitus (GDM)-complicated pregnancies could affect maternal cardiometabolic health after delivery, resulting in hepatic dysfunction and a heightened risk of developing non-alcoholic fatty liver disease (NAFLD). Hence, this study aims to summarise existing literature on the impact of GDM on NAFLD in mothers and investigate the intergenerational impact on NAFLD in offspring.

Methods

Using 4 databases (PubMed, Embase, Web of Science and Scopus) between January 1980 and December 2023, randomized controlled trials and observational studies that assessed the effect of maternal GDM on intergenerational liver outcomes were extracted and analysed using random-effects meta-analysis to investigate the effect of GDM on NAFLD in mothers and offspring. Pooled odds ratio (OR) was calculated using hazards ratio (HR), relative risk (RR), or OR reported from each study, with corresponding 95% confidence intervals (CI), and statistical heterogeneity was assessed with the Cochran Q-test and I2 statistic, with two-sided p values. The study protocol was pre-registered on PROSPERO (CRD42023392428).

Findings

Twenty studies pertaining to mothers and offspring met the inclusion criteria and 12 papers were included further for meta-analysis on intergenerational NAFLD development. Compared with mothers without a history of GDM, mothers with a history of GDM had a 50% increased risk of developing NAFLD (OR 1.50; 95% CI: 1.21-1.87, over a follow-up period of 16 months-25 years. Similarly, compared with offspring born to non-GDM-complicated pregnancies, offspring born to GDM-complicated pregnancies displayed an approximately two-fold elevated risk of NAFLD development (2.14; 1.57-2.92), over a follow-up period of 1-17.8 years.

Interpretation

This systematic review and meta-analysis suggests that both mothers and offspring from GDM-complicated pregnancies exhibit a greater risk to develop NAFLD. These findings underline the importance of early monitoring of liver function and prompt intervention of NAFLD in both generations from GDM-complicated pregnancies.

Funding

No funding was available for this research.

Early-life exposure to gestational diabetes mellitus predisposes offspring to pediatric nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) has emerged as the prevailing chronic liver disease in the pediatric population due to the global obesity pandemic. Evidence shows that prenatal and postnatal exposure to maternal abnormalities leads to a higher risk of pediatric NAFLD through persistent alterations in developmental programming. Gestational diabetes mellitus (GDM) is a hyperglycemic syndrome which has become the most prevalent complication in pregnant women. An increasing number of both epidemiologic investigations and animal model studies have validated adverse and long-term outcomes in offspring following GDM exposure in utero. Similarly, GDM is considered a crucial risk factor for pediatric NAFLD. This review aimed to summarize currently published studies concerning the inductive roles of GDM in offspring NAFLD development during childhood and adolescence. Dysregulations in hepatic lipid metabolism and gut microbiota in offspring, as well as dysfunctions in the placenta are potential factors in the pathogenesis of GDM-associated pediatric NAFLD. In addition, potentially effective interventions for GDM-associated offspring NAFLD are also discussed in this review. However, most of these therapeutic approaches still require further clinical research for validation.

Association between maternal gestational diabetes and allergic diseases in offspring: a birth cohort study

BACKGROUND

Previous studies have linked gestational diabetes (GDM) with allergies in offspring. However, the effect of specific glucose metabolism metrics was not well characterized, and the role of polyunsaturated fatty acids (PUFAs), a modifier of metabolism and the immune system, was understudied. We aimed to investigate the association between maternal GDM and allergic diseases in children and the interaction between glucose metabolism and PUFAs on allergic outcomes.

METHODS

This prospective cohort study included 706 mother-child dyads from Guangzhou, China. Maternal GDM was diagnosed via a 75-g oral glucose tolerance test (OGTT), and dietary PUFAs were assessed using a validated food frequency questionnaire. Allergic disease diagnoses and the age of onset were obtained from medical records of children within three years old.

RESULTS

Approximately 19.4% of women had GDM, and 51.3% of children had any allergic diseases. GDM was positively associated with any allergic diseases (hazard ratio [HR] 1.40; 95% confidence interval (CI) 1.05-1.88) and eczema (HR 1.44; 95% CI 1.02-1.97). A unit increase in OGTT after two hours (OGTT-2 h) glucose was associated with an 11% (95% CI 2%-21%) higher risk of any allergic diseases and a 17% (95% CI 1-36%) higher risk of food allergy. The positive associations between OGTT-2 h glucose and any allergic diseases were strengthened with decreased dietary a-linolenic acid (ALA) and increased n-6 PUFAs, linoleic acid (LA), LA/ALA ratio, and n-6/n-3 PUFA ratio.

CONCLUSIONS

Maternal GDM was adversely associated with early-life allergic diseases, especially eczema. We were the first to identify OGTT-2 h glucose to be more sensitive in inducing allergy risk and that dietary PUFAs might modify the associations.

Sardinian Infants of Diabetic Mothers: A Metabolomics Observational Study

Gestational diabetes mellitus (GDM) is a condition characterized by glucose intolerance, with hyperglycemia of varying severity with onset during pregnancy. An uncontrolled GDM can lead to an increased risk of morbidity in the fetus and newborn, and an increased risk of obesity or developing type 2 diabetes, hypertension or neurocognitive developmental impairment in adulthood. In this study, we used nuclear magnetic resonance (NMR) spectroscopy and gas chromatography-mass spectrometry (GS-MS) to analyze the urinary metabolomic profile of newborns of diabetic mothers (NDMs) with the aim of identifying biomarkers useful for the monitoring of NDMs and for early diagnosis of predisposition to develop related chronic diseases. A total of 26 newborns were recruited: 21 children of diabetic mothers, comprising 13 in diet therapy (NDM-diet) and 8 in insulin therapy (NDM-insulin), and 5 control children of non-diabetic mothers (CTR). Urine samples were collected at five time points: at birth (T1), on the third day of life (T2), one week (T3), one month (T4) and six months postpartum (T5). At T1, variations were observed in the levels of seven potential biomarkers (acetate, lactate, glycylproline/proline, isocitrate, N,N-dimethylglycine, N-acetylglucosamine and N-carbamoyl-aspartate) in NMD-insulin infants compared to NDM-diet and CTR infants. In particular, the altered metabolites were found to be involved in several metabolic pathways such as citrate metabolism, glycine, serine and threonine metabolism, arginine and proline metabolism, amino sugar and nucleotide sugar metabolism, and pyruvate metabolism. In contrast, these changes were not visible at subsequent sampling times. The impact of early nutrition (maternal and formula milk) on the metabolomic profile was considered as a potential contributing factor to this finding.

Intrauterine Growth Restriction Due to Gestational Diabetes: From Pathophysiology to Diagnosis and Management

Intrauterine growth restriction (IUGR) represents a condition where the fetal weight is less than the 10th percentile for gestational age, or the estimated fetal weight is lower than expected based on gestational age. IUGR can be caused by various factors such as maternal, placental or fetal factors and can lead to various complications for both the fetus and the mother, including fetal distress, stillbirth, preterm delivery, and maternal hypertension. Women with gestational diabetes are at an increased risk of developing IUGR. This article reviews the different aspects of gestational diabetes in addition to IUGR, the diagnostic methods available for IUGR detection, including ultrasound and Doppler studies, discusses the management strategies for women with IUGR and gestational diabetes and analyzes the importance of early detection and timely intervention to improve pregnancy outcomes.

The impact of maternal diabetes on birth to placental weight ratio and umbilical cord oxygen values with implications for fetal-placental development

INTRODUCTION

We determined the impact of gestational diabetes (GDM) and pre-existing diabetes (DM) on birth/placental weight and cord oxygen values with implications for placental efficiency and fetal-placental growth and development.

METHODS

A hospital database was used to obtain birth/placental weight, cord PO₂ and other information on patients delivering between Jan 1, 1990 and Jun 15, 2011 with GA >34 weeks (N = 69,854). Oxygen saturation was calculated from the cord PO₂ and pH data, while fetal O₂ extraction was calculated from the oxygen saturation data. The effect of diabetic status on birth/placental weight and cord oxygen values was examined adjusting for covariates.

RESULTS

Birth/placental weights were stepwise decreased in GDM and DM compared to non-diabetics with placentas disproportionally larger indicating decreasing placental efficiency. Umbilical vein oxygen was marginally increased in GDM but decreased in DM attributed to the previously reported hyper-vascularization in diabetic placentas with absorbing surface area of capillaries initially increased, but then constrained by increasing distance from maternal blood within the intervillous space. Umbilical artery oxygen was unchanged in GDM and DM, with fetal O₂ extraction decreased in DM indicating that fetal O₂ delivery must be increased relative to O₂ consumption and likely due to increased umbilical blood flow.

DISCUSSION

Increased villous density/hyper-vascularization in GDM and DM with placentas disproportionately larger and umbilical blood flow increased, are postulated to normalize umbilical artery oxygen despite increased birth weights and growth-related O₂ consumption. These findings have implications for mechanisms signaling fetal-placental growth and development in diabetic pregnancies and differ from that reported with maternal obesity.

Increased variability of fetal heart rate during labour: a review of preclinical and clinical studies

Increased fetal heart rate variability (FHRV) in intrapartum cardiotocographic recording has been variably defined and poorly understood, limiting its clinical utility. Both preclinical (animal) and clinical (human) evidence support that increased FHRV is observed in the early stage of intrapartum fetal hypoxaemia but can also be observed in a subset of fetuses during the preterminal stage of repeated hypoxaemia. This review of available evidence provides data and expert opinion on the pathophysiology of increased FHRV, its clinical significance and a stepwise approach regarding the management of this pattern, and propose recommendations for standardisation of related terminology.

Fetoplacental oxygen homeostasis in pregnancies with maternal diabetes mellitus and obesity

Despite improvements in clinical management, pregnancies complicated by pre-existing diabetes mellitus, gestational diabetes mellitus or obesity carry substantial risks for parent and offspring. Some of the endocrine and metabolic changes in parent and fetus in diabetes mellitus and obesity lead to fetal oxygen deficit, mostly due to insulin-induced accelerated fetal metabolism. The human fetus deals with reduced oxygenation through a wide range of adaptive responses that act at various levels in the placenta as well as the fetus. These responses ensure adequate oxygen delivery to the fetus, increase the oxygen transport capacity of fetal blood and redistribute oxygen-rich blood to vital organs such as the brain and heart. The liver has a central role in adapting to reduced oxygenation by increasing its oxygen extraction and stimulating erythropoietin synthesis to increase haematocrit. The type of adaptive response depends on the onset and duration of hypoxia and the severity of the metabolic disturbance. In pregnancies characterized by diabetes mellitus or obesity, these adaptive systems come under additional strain owing to the increased maternal supply of glucose and resultant fetal hyperinsulinaemia, both of which stimulate oxidative metabolism. In the rare situation that the adaptive responses are overwhelmed, stillbirth can ensue.

Factors early in life associated with hepatic steatosis

BACKGROUND

The rise in prevalence of non-alcoholic fatty liver disease (NAFLD) mirrors the obesity epidemic. NAFLD is insidious but may gradually progress from simple steatosis to steatohepatitis, fibrosis and cirrhosis and/or hepatocellular carcinoma. Intervention strategies to ameliorate developmental programming of NAFLD may be more efficacious during critical windows of developmental plasticity.

AIM

To review the early developmental factors associated with NAFLD.

METHODS

Databases MEDLINE via PubMed, and EMBASE and Reference Citation Analysis were searched and relevant publications up to April 30, 2021 were assessed. Original research studies that included risk factors associated with early development of NAFLD in human subjects were included. These factors include: Maternal factors, intrauterine and prenatal factors, post-natal factors, genetic and ethnic predisposition, childhood and adolescence environmental factors. Studies were excluded if they were review articles or animal studies, case reports or conference abstracts, or if NAFLD was not clearly defined and assessed radiologically.

RESULTS

Of 1530 citations identified by electronic search, 420 duplicates were removed. Of the 1110 citations screened from title and abstract, 80 articles were included in the final analysis. Genetic polymorphisms such as patatin-like phospholipase domain-containing protein 3 (PNPLA3) and membrane-bound O-acyltransferase domain-containing protein 7 (MBOAT7) were associated with increased risk of NAFLD. Familial factors such as maternal obesogenic environment and parental history of hepatic steatosis was associated with offspring NAFLD. Longer duration of exclusive breastfeeding in infancy was associated with a lower risk of developing NAFLD later in life while metabolic dysfunction and/or obesity in adolescence was associated with increased risk of NAFLD. Studies relating to socioeconomic factors and its association with NAFLD reported confounding results.

CONCLUSION

Maternal metabolic dysfunction during pregnancy, being exclusively breastfed for a longer time postnatally, diet and physical activity in childhood and adolescence are potential areas of intervention to decrease risk of NAFLD.

Prenatal Hypoxia Affects Foetal Cardiovascular Regulatory Mechanisms in a Sex- and Circadian-Dependent Manner: A Review

Prenatal hypoxia during the prenatal period can interfere with the developmental trajectory and lead to developing hypertension in adulthood. Prenatal hypoxia is often associated with intrauterine growth restriction that interferes with metabolism and can lead to multilevel changes. Therefore, we analysed the effects of prenatal hypoxia predominantly not associated with intrauterine growth restriction using publications up to September 2021. We focused on: (1) The response of cardiovascular regulatory mechanisms, such as the chemoreflex, adenosine, nitric oxide, and angiotensin II on prenatal hypoxia. (2) The role of the placenta in causing and attenuating the effects of hypoxia. (3) Environmental conditions and the mother's health contribution to the development of prenatal hypoxia. (4) The sex-dependent effects of prenatal hypoxia on cardiovascular regulatory mechanisms and the connection between hypoxia-inducible factors and circadian variability. We identified that the possible relationship between the effects of prenatal hypoxia on the cardiovascular regulatory mechanism may vary depending on circadian variability and phase of the days. In summary, even short-term prenatal hypoxia significantly affects cardiovascular regulatory mechanisms and programs hypertension in adulthood, while prenatal programming effects are not only dependent on the critical period, and sensitivity can change within circadian oscillations.

Immunometabolic adaptation and immune plasticity in pregnancy and the bi-directional effects of obesity

Mandatory maternal metabolic and immunological changes are essential to pregnancy success. Parallel changes in metabolism and immune function make immunometabolism an attractive mechanism to enable dynamic immune adaptation during pregnancy. Immunometabolism is a burgeoning field with the underlying principle being that cellular metabolism underpins immune cell function. With whole body changes to the metabolism of carbohydrates, protein and lipids well recognised to occur in pregnancy and our growing understanding of immunometabolism as a determinant of immunoinflammatory effector responses, it would seem reasonable to expect immune plasticity during pregnancy to be linked to changes in the availability and handling of multiple nutrient energy sources by immune cells. While studies of immunometabolism in pregnancy are only just beginning, the recognised bi-directional interaction between metabolism and immune function in the metabolic disorder obesity might provide some of the earliest insights into the role of immunometabolism in immune plasticity in pregnancy. Characterised by chronic low-grade inflammation including in pregnant women, obesity is associated with numerous adverse outcomes during pregnancy and beyond for both mother and child. Concurrent changes in metabolism and immunoinflammation are consistently described but any causative link is not well established. Here we provide an overview of the metabolic and immunological changes that occur in pregnancy and how these might contribute to healthy versus adverse pregnancy outcomes with special consideration of possible interactions with obesity.

The Origins of NAFLD: The Potential Implication of Intrauterine Life and Early Postnatal Period

Fetal life and the first few months after birth represent a plastic age, defined as a “window of opportunity”, as the organism is particularly susceptible to environmental pressures and has to adapt to environmental conditions. Several perturbations in pregnancy, such as excessive weight gain, obesity, gestational diabetes mellitus and an inadequate or high-fat diet, have been associated with long-term metabolic consequences in offspring, even without affecting birth weight. Moreover, great interest has also been focused on the relationship between the gut microbiome of early infants and health status in later life. Consistently, in various epidemiological studies, a condition of dysbiosis has been associated with an increased inflammatory response and metabolic alterations in the host, with important consequences on the intestinal and systemic health of the unborn child. This review aims to summarize the current knowledge on the origins of NAFLD, with particular attention to the potential implications of intrauterine life and the early postnatal period. Due to the well-known association between gut microbiota and the risk of NAFLD, a specific focus will be devoted to factors affecting early microbiota formation/composition.

Tissue-specific responses that constrain glucose oxidation and increase lactate production with the severity of hypoxemia in fetal sheep

Fetal hypoxemia decreases insulin and increases cortisol and norepinephrine concentrations and may restrict growth by decreasing glucose utilization and altering substrate oxidation. Specifically, we hypothesized that hypoxemia would decrease fetal glucose oxidation and increase lactate and pyruvate production. We tested this by measuring whole body glucose oxidation and lactate production, and molecular pathways in liver, muscle, adipose, and pancreas tissues of fetuses exposed to maternal hypoxemia for 9 days (HOX) compared with control fetal sheep (CON) in late gestation. Fetuses with more severe hypoxemia had lower whole body glucose oxidation rates, and HOX fetuses had increased lactate production from glucose. In muscle and adipose tissue, expression of the glucose transporter GLUT4 was decreased. In muscle, pyruvate kinase (PKM) and lactate dehydrogenase B (LDHB) expression was decreased. In adipose tissue, LDHA and lactate transporter (MCT1) expression was increased. In liver, there was decreased gene expression of PKLR and MPC2 and phosphorylation of PDH, and increased LDHA gene and LDH protein abundance. LDH activity, however, was decreased only in HOX skeletal muscle. There were no differences in basal insulin signaling across tissues, nor differences in pancreatic tissue insulin content, β-cell area, or genes regulating β-cell function. Collectively, these results demonstrate coordinated metabolic responses across tissues in the hypoxemic fetus that limit glucose oxidation and increase lactate and pyruvate production. These responses may be mediated by hypoxemia-induced endocrine responses including increased norepinephrine and cortisol, which inhibit pancreatic insulin secretion resulting in lower insulin concentrations and decreased stimulation of glucose utilization.NEW & NOTEWORTHY Hypoxemia lowered fetal glucose oxidation rates, based on severity of hypoxemia, and increased lactate production. This was supported by tissue-specific metabolic responses that may result from increased norepinephrine and cortisol concentrations, which decrease pancreatic insulin secretion and insulin concentrations and decrease glucose utilization. This highlights the vulnerability of metabolic pathways in the fetus and demonstrates that constrained glucose oxidation may represent an early event in response to sustained hypoxemia and fetal growth restriction.

Melatonin Administration Prevents Placental and Fetal Changes Induced by Gestational Diabetes

Gestational diabetes mellitus (GDM) promotes changes in the placenta and fetuses, due to oxidative stress. Antioxidants can reduce oxidative stress in the placenta. We tested the hypothesis that melatonin (Mel) can prevent these effects in the placenta and fetuses, analyzing their histology, histochemistry, morphometry, and immunohistochemistry. Thirty albino rats were used, divided into groups: CG-pregnant non-diabetic rats; GD-pregnant diabetic rats; GD + Mel-pregnant diabetic rats treated with melatonin. Diabetes was induced by streptozotocin at a dosage of 50 mg/kg i.p. Melatonin was administered in daily injections of 0.8 mg/kg i.p. Melatonin prevented the placental weight and fetal weight and length from increasing, in addition to histomoformetric, histochemical, and immunohistochemical changes in the placentas, compared to the placentas of diabetic females (GD). Thus, we conclude that melatonin has a great potential to prevent placental changes due to GDM.

Transient Hyperglycemia and Hypoxia Induce Memory Effects in AngiomiR Expression Profiles of Feto-Placental Endothelial Cells

Gestational diabetes (GDM) and preeclampsia (PE) are associated with fetal hyperglycemia, fetal hypoxia, or both. These adverse conditions may compromise fetal and placental endothelial cells. In fact, GDM and PE affect feto-placental endothelial function and also program endothelial function and cardiovascular disease risk of the offspring in the long-term. MicroRNAs are short, non-coding RNAs that regulate protein translation and fine tune biological processes. A group of microRNAs termed angiomiRs is particularly involved in the regulation of endothelial function. We hypothesized that transient hyperglycemia and hypoxia may alter angiomiR expression in feto-placental endothelial cells (fpEC). Thus, we isolated primary fpEC after normal, uncomplicated pregnancy, and induced hyperglycemia (25 mM) and hypoxia (6.5%) for 72 h, followed by reversal to normal conditions for another 72 h. Current vs. transient effects on angiomiR profiles were analyzed by RT-qPCR and subjected to miRNA pathway analyses using DIANA miRPath, MIENTURNET and miRPathDB. Both current and transient hypoxia affected angiomiR profile stronger than current and transient hyperglycemia. Both stimuli altered more angiomiRs transiently, i.e., followed by 72 h culture at control conditions. Pathway analysis revealed that hypoxia significantly altered the pathway ‘Proteoglycans in cancer’. Transient hypoxia specifically affected miRNAs related to ‘adherens junction’. Our data reveal that hyperglycemia and hypoxia induce memory effects on angiomiR expression in fpEC. Such memory effects may contribute to long-term adaption and maladaption to hyperglycemia and hypoxia.

Intrapartal cardiotocographic patterns and hypoxia-related perinatal outcomes in pregnancies complicated by gestational diabetes mellitus

AIMS

In previous reports, cardiotocographic (CTG) fetal heart rate (FHR) monitoring has shown only limited benefits in decreasing adverse perinatal outcomes in pregnancies complicated by gestational diabetes mellitus (GDM). The aim of the present study was to evaluate whether an association exists between the recently reported ZigZag pattern (FHR baseline amplitude changes of > 25 bpm with a duration of 2-30 min) and asphyxia-related neonatal outcomes in GDM pregnancies.

METHODS

Intrapartal CTGs were recorded in a one-year cohort of 5150 singleton childbirths. The following CTG changes were evaluated: ZigZag pattern, saltatory pattern, late decelerations, episodes of tachycardia and bradycardia, reduced variability, and uterine tachysystole. The cohort was divided into three groups: women with GDM, women with normal oral glucose tolerance test (OGTT), and women with no OGTT performed. Umbilical artery (UA) blood gases, Apgar scores, neonatal respiratory distress, and neonatal encephalopathy were used as outcome variables.

RESULTS

GDM was diagnosed in 624 (12.1%), OGTT was normal in 4115 (79.9%), and OGTT was not performed in 411 (8.0%) women. Hypoxia-related ZigZag patterns (OR 1.94, 95% CI 1.64-2.34) and late decelerations (OR 1.65, 95% CI 1.27-2.13) of FHR, as well as a greater risk of fetal asphyxia (UA pH < 7.10 and/or UA BE < -12.0 meq/L and/or Apgar scores < 7 at 5-min) (OR 6.64, 95% CI 1.84-12.03) were observed in those with GDM compared with those without GDM.

CONCLUSIONS

GDM is associated with intrapartal ZigZag pattern and late decelerations, cord blood acidemia and low 5-min Apgar scores at birth indicating increased occurrence of fetal hypoxia in GDM pregnancies.

Increased Fetal Cardiovascular Disease Risk: Potential Synergy Between Gestational Diabetes Mellitus and Maternal Hypercholesterolemia

Cardiovascular diseases (CVD) remain a major cause of death worldwide. Evidence suggests that the risk for CVD can increase at the fetal stages due to maternal metabolic diseases, such as gestational diabetes mellitus (GDM) and maternal supraphysiological hypercholesterolemia (MSPH). GDM is a hyperglycemic, inflammatory, and insulin-resistant state that increases plasma levels of free fatty acids and triglycerides, impairs endothelial vascular tone regulation, and due to the increased nutrient transport, exposes the fetus to the altered metabolic conditions of the mother. MSPH involves increased levels of cholesterol (mainly as low-density lipoprotein cholesterol) which also causes endothelial dysfunction and alters nutrient transport to the fetus. Despite that an association has already been established between MSPH and increased CVD risk, however, little is known about the cellular processes underlying this relationship. Our knowledge is further obscured when the simultaneous presentation of MSPH and GDM takes place. In this context, GDM and MSPH may substantially increase fetal CVD risk due to synergistic impairment of placental nutrient transport and endothelial dysfunction. More studies on the separate and/or cumulative role of both processes are warranted to suggest specific treatment options.

The diagnostic indicators of gestational diabetes mellitus from second trimester to birth: a systematic review

BACKGROUND

Gestational diabetes mellitus (GDM) is glucose intolerance first recognised during pregnancy. Both modalities and thresholds of the GDM diagnostic test, the Oral Glucose Tolerance Test (OGTT), have varied widely over time and among countries. Additionally, OGTT limitations include inconsistency, poor patient tolerability, and questionable diagnostic reliability. Many biological parameters have been reported to be modified by GDM and could potentially be used as diagnostic indicators. This study aimed to 1) systematically explore biomarkers reported in the literature as differentiating GDM from healthy pregnancies 2) screen those indicators assessed against OGTT to propose OGTT alternatives.

MAIN BODY

A systematic review of GDM diagnostic indicators was performed according to PRISMA guidelines (PROSPERO registration CRD42020145499). Inclusion criteria were full-text, comprehensible English-language articles published January 2009-January 2021, where a biomarker (from blood, ultrasound, amniotic fluid, placenta) was compared between GDM and normal glucose tolerance (NGT) women from the second trimester onward to immediately postpartum. GDM diagnostic method had to be clearly specified, and the number of patients per study higher than 30 in total or 15 per group. Results were synthesised by biomarkers.

RESULTS

Of 13,133 studies identified in initial screening, 174 studies (135,801 participants) were included. One hundred and twenty-nine studies described blood analytes, one amniotic fluid analytes, 27 ultrasound features, 17 post-natal features. Among the biomarkers evaluated in exploratory studies, Adiponectin, AFABP, Betatrophin, CRP, Cystatin-C, Delta-Neutrophil Index, GGT, TNF-A were those demonstrating statistically and clinically significant differences in substantial cohorts of patients (> 500). Regarding biomarkers assessed versus OGTT (i.e. potential OGTT alternatives) most promising were Leptin > 48.5 ng/ml, Ficolin3/adiponectin ratio ≥ 1.06, Chemerin/FABP > 0.71, and Ultrasound Gestational Diabetes Score > 4. These all demonstrated sensitivity and specificity > 80% in adequate sample sizes (> / = 100).

CONCLUSIONS

Numerous biomarkers may differentiate GDM from normoglycaemic pregnancy. Given the limitations of the OGTT and the lack of a gold standard for GDM diagnosis, advanced phase studies are needed to triangulate the most promising biomarkers. Further studies are also recommended to assess the sensitivity and specificity of promising biomarkers not yet assessed against OGTT.

TRIAL REGISTRATION

PROSPERO registration number CRD42020145499.

Gestational diabetes and childhood asthma in a racially diverse US pregnancy cohort

BACKGROUND

Childhood asthma is a common chronic disease that likely has prenatal origins. Gestational diabetes alters maternal physiology and may influence fetal risk for childhood-onset disease. However, the association between gestational diabetes and child asthma is not well characterized.

OBJECTIVE

To investigate the association between gestational diabetes and wheeze/asthma at approximately 4 years of age in a racially diverse US cohort.

METHODS

We studied mother-child dyads enrolled prenatally in the Conditions Affecting Neurocognitive Development and Learning in Early Childhood study. Gestational diabetes was determined by medical chart review. At approximately 4 years of age, we assessed child respiratory outcomes including parent report of physician-diagnosed asthma (ever), current wheeze (symptoms within the past 12 months), and current asthma (physician diagnosis and/or medication or symptoms within the past 12 months). We used the modified Poisson regression to assess associations between gestational diabetes and child respiratory outcomes, adjusting for maternal age, race, prenatal smoking, pre-pregnancy body mass index, parity, asthma history, socioeconomic status, and infant sex.

RESULTS

Among 1107 women, 66% were African American/Black. Six percent (n = 62) had gestational diabetes documented during pregnancy. Gestational diabetes was associated with increased risk of physician-diagnosed asthma (adjusted risk ratio (RR) [95% Confidence Interval]: 2.13 [1.35, 3.38]; prevalence: 14%), current wheeze (RR: 1.85 [1.23, 2.78]; prevalence: 19%), and current asthma (RR: 2.01 [1.30, 3.10]; prevalence: 16%).

CONCLUSIONS

Gestational diabetes was associated with increased risk of asthma and wheeze outcomes. Additional studies are needed to elucidate modifiable pathways underlying this association.

Association between maternal diabetes mellitus and allergic diseases in children - A systematic review and meta-analysis

BACKGROUND

Existing knowledge suggests that gestational diabetes mellitus was inconsistently associated with offspring allergic diseases. The aim of this study was to identify the association between maternal diabetes mellitus and the risk of offspring allergic diseases by systematic review.

METHODS

We searched and retrieved three databases (PubMed, Web of Science, and Cochrane Library) for articles on the association between maternal diabetes mellitus and offspring allergic diseases published before December 31, 2019. Stata software version 16.0 was used for statistical analysis.

RESULTS

Eight published studies were included in this meta-analysis. The pooled effect estimates showed the association between maternal diabetes mellitus and allergic outcomes, including asthma (OR: 1.13, 95% CI: 1.01-1.27), wheezing (OR: 1.13, 95% CI: 1.07-1.21), and atopic dermatitis (OR: 1.43, 95% CI: 1.22-1.57). Maternal diabetes mellitus was not associated with the risk of allergic sensitization, with a pooled effect estimate of 1.07 (95% CI: 0.45, 2.58).

CONCLUSION

Maternal diabetes mellitus may increase the risk of allergic diseases in their children. However, this finding should be validated with future large-sample epidemiological studies covering a wider spectrum of allergic diseases.

Effects of Maternal Obesity and Gestational Diabetes Mellitus on the Placenta: Current Knowledge and Targets for Therapeutic Interventions

Obesity and gestational diabetes mellitus (GDM) are becoming more common among pregnant women worldwide and are individually associated with a number of placenta-mediated obstetric complications, including preeclampsia, macrosomia, intrauterine growth restriction and stillbirth. The placenta serves several functions throughout pregnancy and is the main exchange site for the transfer of nutrients and gas from mother to fetus. In pregnancies complicated by maternal obesity or GDM, the placenta is exposed to environmental changes, such as increased inflammation and oxidative stress, dyslipidemia, and altered hormone levels. These changes can affect placental development and function and lead to abnormal fetal growth and development as well as metabolic and cardiovascular abnormalities in the offspring. This review aims to summarize current knowledge on the effects of obesity and GDM on placental development and function. Understanding these processes is key in developing therapeutic interventions with the goal of mitigating these effects and preventing future cardiovascular and metabolic pathology in subsequent generations.

Placental structural abnormalities in gestational diabetes and when they develop: A scoping review

Gestational diabetes mellitus (GDM) is defined as diabetes with onset or first recognition during gestation. It is a common complication of pregnancy that has become more prevalent over the past few decades. Abnormalities in fetal growth, including increased incidence of both large and small for gestational age babies, suggest placental dysfunction. The major goal of this scoping review is to determine what is known about abnormalities in placentas delivered from GDM pregnancies, and how early in gestation these abnormalities arise. A secondary goal is to review to what extent other selected factors, in particular obesity, have been found to influence or modify the reported effects of GDM on placental development, and whether these are considered in the study of GDM placentas. PubMed and Scopus databases were searched using the key terms: "gestational diabetes AND (woman OR human) AND placenta AND (ultrasound OR ultrastructure OR imaging OR histology OR pathology). Studies of gross morphology and histoarchitecture in placentas delivered from GDM pregnancies consistently report increased placental size, villous immaturity and a range of vascular lesions when compared to uncomplicated pregnancies. In contrast, a small number of ultrasound studies have examined placental development in GDM pregnancies in the second, and especially, the first trimester. Relatively few studies have analyzed interactions with maternal BMI, but these do suggest that it may play a role in placental abnormalities. Further examination of placental development early in pregnancy is needed to understand when it becomes disrupted in GDM, as a first step to identifying the underlying causes.

Cinnamaldehyde mitigates placental vascular dysfunction of gestational diabetes and protects from the associated fetal hypoxia by modulating placental angiogenesis, metabolic activity and oxidative stress

Gestational diabetes mellitus (GDM) is a major pregnancy-related disorder with an increasing prevalence worldwide. GDM is associated with altered placental vascular functions and has severe consequences for fetal growth. There is no commonly accepted medication for GDM due to safety considerations. Actions of the currently limited therapeutic options focus exclusively on lowering the blood glucose level without paying attention to the altered placental vascular reactivity and remodelling. We used the fat-sucrose diet/streptozotocin (FSD/STZ) rat model of GDM to explore the efficacy of cinnamaldehyde (Ci; 20 mg/kg/day), a promising antidiabetic agent for GDM, and glyburide/metformin-HCl (Gly/Met; 0.6 + 100 mg/kg/day), as a reference drug for treatment of GDM, on the placenta structure and function at term pregnancy after their oral intake one week before mating onward. Through genome-wide transcriptome, biochemical, metabolome, metal analysis and histopathology we obtained an integrated understanding of their effects. GDM resulted in maternal and fetal hyperglycemia, fetal hyperinsulinemia and placental dysfunction with subsequent fetal anemia, hepatic iron deficiency and high serum erythropoietin level, reflecting fetal hypoxia. Differentially-regulated genes were overrepresented for pathways of angiogenesis, metabolic transporters and oxidative stress. Despite Ci and Gly/Met effectively alleviated the maternal and fetal glycemia, only Ci offered substantial protection from GDM-associated placental vasculopathy and prevented the fetal hypoxia. This was explained by Ci's impact on the molecular regulation of placental angiogenesis, metabolic activity and redox signaling. In conclusion, Ci provides a dual impact for the treatment of GDM at both maternal and fetal levels through its antidiabetic effect and the direct placental vasoprotective action. Lack of Gly/Met effectiveness to restore it's impaired functionality demonstrates the vital role of the placenta in developing efficient medications for GDM.

Placental Magnetic Resonance Imaging: A Method to Evaluate Placental Function In Vivo

This article describes the use of placental magnetic resonance imaging (MRI) relaxation times in the in vivo assessment of placental function. It focuses on T2*-weighted placental MRI, the main area of the authors' research over the past decade. The rationale behind T2*-weighted placental MRI, the main findings reported in the literature, and directions for future research and clinical applications of this method are discussed. The article concludes that placental T2* relaxation time is an easily obtained and robust measurement, which can discriminate between normal and dysfunctional placenta. Placenta T2* is a promising tool for in vivo assessment of placental function.

The role of obesity and gestational diabetes on placental size and fetal oxygenation

INTRODUCTION

Maternal pregestational obesity is a significant risk factor for adverse pregnancy outcomes, such as gestational diabetes. Both these conditions can have an impact on placental development and affect maternal-fetal exchanges, compromising fetal metabolic status. The aim of the study is to investigate the influence of pre-pregnancy BMI on placental size and to evaluate the role of obesity and gestational diabetes mellitus (GDM) on fetal oxygenation in overweight and obese pregnant women.

METHODS

208 normal weight (NW), 57 overweight (OW) and 69 obese (OB) women were studied at elective cesarean section (CS) at term. 10 OW and 24 OB women were affected by GDM. Maternal, fetal and placental data were collected. Respiratory gases and acid-base balance were measured in umbilical venous and arterial blood.

RESULTS

Placental weight and thickness were higher in OB pregnancies. Lower fetal-placental ratios (F/P) were found in GDM pregnancies, both OW and OB. Fetuses from OB mothers were more hypoxic and acidemic compared to NW, particularly when complicated by GDM.

DISCUSSION

In agreement with previous studies, our data show that placentas from OB and GDM pregnancies are heavier and thicker, suggesting that an unbalanced pregestational nutritional status can decrease the placental efficiency in maternal-fetal exchanges. Fetuses from obese women are also hypoxic and acidemic, while fetuses from gestational diabetic mothers are hypoxic, reflecting that an altered pre-pregnancy BMI can affect fetal oxygenation, and GDM can play an additional detrimental role, thus worsening placental function and fetal oxygenation.

[Comparative morphofunctional analysis of the state of fetoplacental complex in diabetes mellitus (literature review)]

This article reviews the literature on placental morphofunctional changes in placenta of patients with type 1 and type 2 diabetes mellitus and gestational diabetes mellitus. The detailed analysis of features of pathogenesis of various abnormalities of the fetoplacental complex depending on the type of diabetes, its influence on the formation of the placental vascular bed. The analysis of mechanisms of development of placenta formation disorders, pathologies of placental vascular bed, the role of hyperglycemia and hyperinsulinemia in villous maturation, placental weight gain, perinatal outcomes. The discussed anomalies have a significant impact on the fetoplacental complex, acting as epigenetic factors, forming the environment for the fetus, which may later affect the health of the unborn child. They lead to adverse perinatal outcomes, including high infant morbidity and mortality. Literature search was performed in Russian (eLibrary, CyberLeninka.ru) and international (PubMed, Cochrane Library) databases in Russian and English languages. The free access to the full text of the articles was in priority. The selection of sources was prioritized for the period from 2016 to 2020. However, due to the lack of knowledge of the chosen topic, the selection of sources was dated from 2001.

Clinical Importance of the Human Umbilical Artery Potassium Channels

Potassium (K⁺) channels are usually predominant in the membranes of vascular smooth muscle cells (SMCs). These channels play an important role in regulating the membrane potential and vessel contractility-a role that depends on the vascular bed. Thus, the activity of K⁺ channels represents one of the main mechanisms regulating the vascular tone in physiological and pathophysiological conditions. Briefly, the activation of K⁺ channels in SMC leads to hyperpolarization and vasorelaxation, while its inhibition induces depolarization and consequent vascular contraction. Currently, there are four different types of K⁺ channels described in SMCs: voltage-dependent K⁺ (K_V) channels, calcium-activated K⁺ (K_Ca) channels, inward rectifier K⁺ (Kir) channels, and 2-pore domain K⁺ (K_2P) channels. Due to the fundamental role of K⁺ channels in excitable cells, these channels are promising therapeutic targets in clinical practice. Therefore, this review discusses the basic properties of the various types of K⁺ channels, including structure, cellular mechanisms that regulate their activity, and new advances in the development of activators and blockers of these channels. The vascular functions of these channels will be discussed with a focus on vascular SMCs of the human umbilical artery. Then, the clinical importance of K⁺ channels in the treatment and prevention of cardiovascular diseases during pregnancy, such as gestational hypertension and preeclampsia, will be explored.

Disruption of fertility, placenta, pregnancy outcome, and multigenerational inheritance of hepatic steatosis by organotin exposure from contaminated seafood in rats

Early life exposure to endocrine-disrupting chemicals (EDCs) is an emerging risk factor for development of complications later in life and in subsequent generations. We previously demonstrated that exposure to the EDC organotin (OT), which is present in contaminated seafood, resulted in reproductive abnormalities in female rats. However, few studies have explored the effect of OT accumulation in seafood on pregnancy outcomes. This led us to consider the potential effects of the OT present in seafood on fertility, pregnancy, the placenta, and the offspring. In this investigation, we assessed whether exposure to the OT in contaminated seafood resulted in abnormal fertility and pregnancy features and offspring complications. OT in contaminated seafood (LNI) was administered to female rats, and their fertility, pregnancy outcomes, and fetal liver morphology were assessed. LNI caused abnormal fertility, a reduction in the total number of pups, and an increase in serum testosterone levels compared to controls. Furthermore, LNI exposure caused irregular uterine morphology with inflammation and fibrosis and led to a reduction in embryonic implantation. In pregnant rats, LNI caused abnormal lipid profiles and livers with steatosis features. LNI exposure also causes placental morpho-physiology disruption, a high presence of glycogen and inflammatory cells, and irregular lipid profiles. In addition, LNI exposure caused an increase in large amounts of carbohydrate and lipid delivery to the fetus via an increase in placental nutrient sensor protein expressions (GLUT1, IRβ/mTOR and Akt). In both genders of offspring, LNI exposure led to an increase in body weights, liver megakaryocytes, lipid accumulation, and oxidative stress (OS) levels. Collectively, these data suggest that OT exposure from contaminated seafood in female rats leads to reduced fertility, uterine implantation failure, pregnancy and placental metabolic outcome irregularities, offspring adiposity, liver steatosis, and an increase in OS. Furthermore, some of the effects of OT may be the result of obesogenic and multigenerational effects of OT in adult female rats.

Immunological Role of the Maternal Uterine Microbiota in Postpartum Hemorrhage

Recent metagenomics and microbiology studies have identified microorganisms that are typical of the fetoplacental unit. Considering this emerging evidence, the placenta, uterus, and the amniotic cavity are not sterile and not immune privileged. However, there is evidence for a beneficial interaction between active maternal immune system and the presence of commensal pathogens, which lead to an immune-tolerant state, thereby preventing fetal rejection. Multiple conditions associated with the loss of the normal flora are described (dysbiosis), which could result in perinatal and puerperal adverse events, including, directly or indirectly, postpartum hemorrhage. Altered flora when associated with a severe proinflammatory state and combined with patient's genetic and environmental factors confers a high-risk adverse outcome. Better understanding of the adverse role of dysbiosis in pregnancy outcome will improve maternal outcome.

Association between insulin and post-caesarean resuscitation rates in infants of women with GDM: A retrospective study

BACKGROUND

Gestational diabetes mellitus (GDM) and caesarean deliveries independently increase the risk of postoperative complications. There are limited data on the influence of insulin use on the outcomes of neonates who were delivered via caesarean section. We sought to investigate the impact of insulin use in women with GDM on resuscitation rates of infants post caesarean delivery.

METHODS

A retrospective database review of women with singleton term (≥ 37 weeks) pregnancies who were on insulin for GDM delivering between January 2005 and December 2014 at a major metropolitan hospital in Sydney.

RESULTS

One thousand eight hundred and fifty-seven women with GDM were identified. The mean age was 31.01 ± 5.63 years and mean gestational period of 39.07 ± 1.00 weeks. 31.0% received insulin treatment for GDM. Women who were on insulin were older (31.9 ± 5.7 vs 30.6 ± 5.6 years, P < 0.001), had a higher body mass index (BMI) (31.2 ± 7.7 vs 29.0 ± 7.4 kg/m2, P < 0.001), higher rates of preeclampsia (7.3% vs 4.1%, P = 0.004), lower rates of alcohol consumption (0.4% vs 1.7%, P = 0.014), and had infants with lower resuscitation rates (21.2% vs 28.6%, P = 0.001). Infants who required resuscitation had a lower gestational age, lower five-minute APGAR score, and lower birth weight, length, and head circumferences. On multivariate analysis, women with GDM treated with insulin (odds ratio [OR] = 0.69, CI = 0.54-0.89, P = 0.004), higher gestational age (OR = 0.88, CI = 0.78-0.99, P = 0.032), higher maternal BMI (OR = 1.02, CI = 1.01-1.04, P = 0.005), and emergency caesarean (OR = 2.33, CI = 1.74-3.12, P < 0.001) independently predicted incidence of resuscitation.

CONCLUSIONS

The findings suggest a relationship between insulin use and reduced resuscitation rates of infants born from mothers with GDM. Further studies investigating the role, dosage, and criteria for insulin use in women with GDM are required.

Expression of placental glucose transporter proteins in pregnancies complicated by fetal growth disorders

During pregnancy fetal growth disorders, including fetal macrosomia and fetal growth restriction (FGR) are associated with numerous maternal-fetal complications, as well as due to the adverse effect of the intrauterine environment lead to an increased morbidity in adult life. Accumulating evidence suggests that occurrence of fetal macrosomia or FGR, may be associated with alterations in the transfer of nutrients across the placenta, in particular of glucose. The placental expression and activity of specific GLUT transporters are the main regulatory factors in the process of maternal-fetal glucose exchange. This review article summarizes the results of previous studies on the expression of GLUT transporters in the placenta, concentrating on human pregnancies complicated by intrauterine fetal growth disorders. Characteristics of each transporter protein found in the placenta is presented, alterations in the location and expression of GLUT isoforms observed in individual placental compartments are described, and the factors regulating the expression of selected GLUT proteins are examined. Based on the above data, the potential function of each GLUT isoform in the maternal-fetal glucose transfer is determined. Further on, a detailed analysis of changes in the expression of glucose transporters in pregnancies complicated by fetal growth disorders is given, and significance of these modifications for the pathogenesis of fetal macrosomia and FGR is discussed. In the final part novel interventional approaches that might reduce the risk associated with abnormalities of intrauterine fetal growth through modifications of placental GLUT-mediated glucose transfer are explored.

Δ9-tetrahydrocannabinol exposure during rat pregnancy leads to symmetrical fetal growth restriction and labyrinth-specific vascular defects in the placenta

1 in 5 women report cannabis use during pregnancy, with nausea cited as their primary motivation. Studies show that (-)-△9-tetrahydrocannabinol (Δ9-THC), the major psychoactive ingredient in cannabis, causes fetal growth restriction, though the mechanisms are not well understood. Given the critical role of the placenta to transfer oxygen and nutrients from mother, to the fetus, any compromise in the development of fetal-placental circulation significantly affects maternal-fetal exchange and thereby, fetal growth. The goal of this study was to examine, in rats, the impact of maternal Δ9-THC exposure on fetal development, neonatal outcomes, and placental development. Dams received a daily intraperitoneal injection (i.p.) of vehicle control or Δ9-THC (3 mg/kg) from embryonic (E)6.5 through 22. Dams were allowed to deliver normally to measure pregnancy and neonatal outcomes, with a subset sacrificed at E19.5 for placenta assessment via immunohistochemistry and qPCR. Gestational Δ9-THC exposure resulted in pups born with symmetrical fetal growth restriction, with catch up growth by post-natal day (PND)21. During pregnancy there were no changes to maternal food intake, maternal weight gain, litter size, or gestational length. E19.5 placentas from Δ9-THC-exposed pregnancies exhibited a phenotype characterized by increased labyrinth area, reduced Epcam expression (marker of labyrinth trophoblast progenitors), altered maternal blood space, decreased fetal capillary area and an increased recruitment of pericytes with greater collagen deposition, when compared to vehicle controls. Further, at E19.5 labyrinth trophoblast had reduced glucose transporter 1 (GLUT1) and glucocorticoid receptor (GR) expression in response to Δ9-THC exposure. In conclusion, maternal exposure to Δ9-THC effectively compromised fetal growth, which may be a result of the adversely affected labyrinth zone development. These findings implicate GLUT1 as a Δ9-THC target and provide a potential mechanism for the fetal growth restriction observed in women who use cannabis during pregnancy.

Effect of gestational diabetes mellitus and pregnancy-induced hypertension on human umbilical vein smooth muscle KATP channels

Gestational diabetes mellitus (GDM) and pregnancy-induced hypertension (PIH) can jeopardize mother and/or fetus. Vascular ATP-sensitive potassium (K_ATP) channels most likely participate in the processes of diabetes and hypertension. The aim of this research was to examine whether GDM and PIH cause changes in the expression and function of K_ATP channels in vascular smooth muscle of human umbilical vein (HUV). Western blot and immunohistochemistry detected significantly decreased expression of Kir6.1 subunit of K_ATP channels in GDM and PIH, while the expression of SUR2B was unchanged. In GDM, a K⁺ channel opener, pinacidil caused reduced relaxation of the endothelium-denuded HUVs compared to normal pregnancy. However, its effects in HUVs from PIH subjects were similar to normal pregnancy. In all groups K_ATP channel blocker glibenclamide antagonized the relaxation of HUV induced by pinacidil without change in the maximal relaxations indicating additional K_ATP channel-independent mechanisms of pinacidil action. Iberiotoxin, a selective antagonist of large-conductance calcium-activated potassium channels, inhibited the relaxant effect of pinacidil in PIH, but not in normal pregnancy and GDM. Experiments performed in K⁺-rich solution confirmed the existence of K⁺-independent effects of pinacidil, which also appear to be impaired in GDM and PIH. Thus, the expression of K_ATP channels is decreased in GDM and PIH. In GDM, vasorelaxant response of HUV to pinacidil is reduced, while in PIH it remains unchanged. It is very likely that K_ATP channels modulation and more detailed insight in K_ATP channel-independent actions of pinacidil may be precious in the therapy of pathological pregnancies.

Role of oxidative stress in neonatal respiratory distress syndrome

Respiratory distress syndrome is the commonest respiratory disorder in preterm infants. Although it is well known that preterm birth has a key role, the mechanisms of lung injury have not been fully elucidated. The pathogenesis of this neonatal condition is based on the rapid formation of the oxygen reactive species, which surpasses the detoxification capacity of anti-oxidative defense system. The high reactivity of free radical leads to damage to a variety of molecules and may induce respiratory cell death. There is evidence that the oxidative stress involved in the physiopathology of this disease, is particularly related to oxygen supplementation, mechanical ventilation, inflammation/infection and diabetes. This narrative review summarizes what is known regarding the connection between oxidative stress and respiratory distress syndrome.

Placental structure in gestational diabetes mellitus

The placenta is a transitory organ, located between the mother and the foetus, which supports intrauterine life. This organ has nutritional, endocrine and immunologic functions to support foetal development. Several factors are related to the correct functioning of the placenta including foetal and maternal blood flow, appropriate nutrients, expression and function of receptors and transporters, and the morphology of the placenta itself. Placental morphology is crucial for understanding the pathophysiology of the organ as represents the physical structure where nutrient exchange occurs. In pathologies of pregnancy such as diabetes mellitus in humans and animal models, several changes in the placental morphology occur, related mainly with placental size, hypervascularization, higher branching capillaries of the villi and increased glycogen deposits among others. Gestational diabetes mellitus is associated with modifications in the structure of the human placenta including changes in the surface area and volume, as well as histological changes including an increased volume of intervillous space and terminal villi, syncytiotrophoblast number, fibrinoid areas, and glycogen deposits. These modifications may result in functional changes in this organ thus limiting the wellbeing of the developing foetus. This review gives an overview of recurrent morphological changes at macroscopic and histological levels seen in the placenta from gestational diabetes in humans and animal models. This article is part of a Special Issue entitled: Membrane Transporters and Receptors in Pregnancy Metabolic Complications edited by Luis Sobrevia.

Mild maternal hyperglycemia in INS C93S transgenic pigs causes impaired glucose tolerance and metabolic alterations in neonatal offspring

Alongside the obesity epidemic, the prevalence of maternal diabetes is rising worldwide, and adverse effects on fetal development and metabolic disturbances in the offspring's later life have been described. To clarify whether metabolic programming effects are due to mild maternal hyperglycemia without confounding obesity, we investigated wild-type offspring of INS^C93S transgenic pigs, which are a novel genetically modified large-animal model expressing mutant insulin (INS) C93S in pancreatic β-cells. This mutation results in impaired glucose tolerance, mild fasting hyperglycemia and insulin resistance during late pregnancy. Compared with offspring from wild-type sows, piglets from hyperglycemic mothers showed impaired glucose tolerance and insulin resistance (homeostatic model assessment of insulin resistance: +3-fold in males; +4.4-fold in females) prior to colostrum uptake. Targeted metabolomics in the fasting and insulin-stimulated state revealed distinct alterations in the plasma metabolic profile of piglets from hyperglycemic mothers. They showed increased levels of acylcarnitines, gluconeogenic precursors such as alanine, phospholipids (in particular lyso-phosphatidylcholines) and α-aminoadipic acid, a potential biomarker for type 2 diabetes. These observations indicate that mild gestational hyperglycemia can cause impaired glucose tolerance, insulin resistance and associated metabolic alterations in neonatal offspring of a large-animal model born at a developmental maturation status comparable to human babies.

Editor's choice: Mild maternal hyperglycemia causes impaired glucose tolerance and metabolic alterations in wild-type neonatal offspring of INS^C93S transgenic pigs, a novel large animal model for mutant INS gene-induced diabetes of youth (MIDY).

Assessment of placental metal levels in a South African cohort

The placenta plays an important role in mediating the effect of maternal metal exposure on fetal development, acting as both barrier and transporter. Term-placenta metal levels serve as an informative snapshot of maternal/fetal exposure during pregnancy and could be used to predict offspring short- and long-term health outcomes. Here, we measured term-placenta metal levels of 11 metals in 42 placentas from the Soweto First 1000 days cohort (S1000, Soweto-Johannesburg, SA). We compared these placental metal concentrations with previously reported global cohort measurements to determine whether this cohort is at increased risk of exposure. Placental metals were tested for correlations to understand potential interactions between metals. Since these samples are from a birth cohort study, we also performed exploratory analyses to determine whether metal levels were associated with placenta and birth outcomes. Most S1000 placental metal levels were similar to other cohorts; however, cadmium (Cd) levels up to 50-fold lower, and essential elements nickel (Ni) and chromium (Cr) level up to 6- and 16-fold lower, respectively. Cd, Se, and Ni were associated with placenta and birth outcomes. Studies are ongoing to examine underlying mechanisms and how these developmental differences affect long-term health.

Fetal hyperglycemia acutely induces persistent insulin resistance in skeletal muscle

Offspring exposed in utero to maternal diabetes exhibit long-lasting insulin resistance, though the initiating mechanisms have received minimal experimental attention. Herein, we show that rat fetuses develop insulin resistance after only 2-day continuous exposure to isolated hyperglycemia starting on gestational day 18. Hyperglycemia-induced reductions in insulin-induced AKT phosphorylation localized primarily to fetal skeletal muscle. The skeletal muscle of hyperglycemia-exposed fetuses also exhibited impaired in vivo glucose uptake. To address longer term impacts of this short hyperglycemic exposure, neonates were cross-fostered and examined at 21 days postnatal age. Offspring formerly exposed to 2 days late gestation hyperglycemia exhibited mild glucose intolerance with insulin signaling defects localized only to skeletal muscle. Fetal hyperglycemic exposure has downstream consequences which include hyperinsulinemia and relative uteroplacental insufficiency. To determine whether these accounted for induction of insulin resistance, we examined fetuses exposed to late gestational isolated hyperinsulinemia or uterine artery ligation. Importantly, 2 days of fetal hyperinsulinemia did not impair insulin signaling in murine fetal tissues and 21-day-old offspring exposed to fetal hyperinsulinemia had normal glucose tolerance. Similarly, fetal exposure to 2-day uteroplacental insufficiency did not perturb insulin-stimulated AKT phosphorylation in fetal rats. We conclude that fetal exposure to hyperglycemia acutely produces insulin resistance. As hyperinsulinemia and placental insufficiency have no such impact, this occurs likely via direct tissue effects of hyperglycemia. Furthermore, these findings show that skeletal muscle is uniquely susceptible to immediate and persistent insulin resistance induced by hyperglycemia.

Altered development of fetal liver perfusion in pregnancies with pregestational diabetes

Background

Pregestational diabetes is associated with fetal macrosomia, and umbilical perfusion of the fetal liver has a role in regulating fetal growth. We therefore hypothesized that pregestational diabetes alters fetal liver blood flow depending on degree of glycemic control.

Methods

In a prospective study, 49 women with pregestational diabetes underwent monthly ultrasound examinations during 24–36 gestational weeks. Blood flow was determined in the umbilical vein, ductus venosus and portal vein, and blood velocity was measured in the left portal vein, the latter reflecting the watershed between splanchnic and umbilical flow. The measurements were compared with reference values by z-score statistics, and the effect of HbA_1c assessed.

Results

The umbilical venous flow to the liver (z-score 0.36, p = 0.002), total venous liver flow (z-score 0.51, p<0.001) and left portal vein blood velocity (z-score 0.64, p<0.001), were higher in the study group. Normalized portal venous flow was lower (z-score -0.42, p = 0.002), and normalized total venous liver flow tended to be lower after 30 gestational weeks (z-score -0.54, p = 0.047) in the diabetic pregnancies compared with reference values from a low-risk population. The left portal vein blood velocity was positively, and the portal fraction of total venous liver flow negatively correlated with first trimester HbA_1C.

Conclusions

In spite of increased umbilical blood distribution to the fetal liver, graded according to glycemic control, the total venous liver flow did not match third trimester fetal growth in pregnancies with pregestational diabetes, thus contributing towards increased perinatal risks and possibly altered liver function with long-term metabolic consequences.

Obstetric and perinatal outcomes of pregnancies according to initial maternal serum HCG concentrations after vitrified-warmed single blastocyst transfer

RESEARCH QUESTION

Do pregnancy, obstetric and perinatal outcomes differ according to initial maternal serum human chorionic gonadotrophin (HCG) level measured on day 11 after single blastocyst transfer?

DESIGN

Vitrified-warmed single blastocyst transfer cycles (n = 640) were collected between 1 January 2013 and 30 April 2017 with positive HCG values and retrospectively analysed by receiver operating characteristic curves to predict clinical pregnancy, ongoing pregnancy and delivery. Cycles were divided into a low HCG group (n = 155) and high HCG group (n = 485) based on cut-off value of live birth prediction. Cycles in the HCG group were subdivided into a low-high subgroup (n = 162), medium-high subgroup (n = 162) and high-high subgroup (n = 161) based on tertile points. Pregnancy rates and obstetric and perinatal outcomes were compared.

RESULTS

The area under curves for clinical pregnancy, ongoing pregnancy and live birth prediction were 0.95, 0.81 and 0.79, respectively; corresponding cut-off values were 152.2 IU/l, 211.9 IU/l and 211.9 IU/l; HCG less than 211.9 IU/l indicated an extremely low clinical pregnancy rate (34.84%), a high early miscarriage rate (61.11%) and a low live birth rate (12.26%). Rates of gestational diabetes mellitus (GDM) (P = 0.007) and female neonates (P = 0.001) were significantly higher in the LHG group compared with the HHG group; no significant differences were observed in the low versus high HCG group overall.

CONCLUSIONS

Lower initial maternal serum HCG levels indicated poorer clinical outcomes. Within the high HCG group, a lower initial maternal HCG level was found to be associated with GDM occurrence and proportion of female neonates.

Pathophysiology of placenta and fetus in diabetes mellitus

Currently, there is a steady increase in the incidence of diabetes mellitus (DM) in the global population, which causes an increase in maternal and perinatal mortality. Children born to mothers with DM have a high risk of not only congenital abnormalities, but also cardiovascular and metabolic disorders in later life. Fetal growth is determined by both the metabolic and nutritional status of the mother, and the placental nutrient transfer capacity. Pregnancy complicated by DM is associated not only with overgrowth of the fetus, but also with the excess deposition of metabolites in the placenta. The role of disorders of carbohydrate metabolism, obesity and other factors in relation to the function of the placenta and fetal growth remains not fully understood. This review provides an overview of the literature on the placental complex status in pregnancy complicated by obesity, as well as pre-gestational and gestational types of DM. The focus is on three key substrates in these conditions: glucose, lipids, and amino acids, and their influence on placental metabolic activity and on the fetus. Improved knowledge of morphology and understanding of changes in the function of the placenta that lead to abnormal growth of the fetus will allow for the development of new therapeutic approaches to improve the outcomes of pregnancy, maternal and child health.

Human fetoplacental arterial and venous endothelial cells are differentially programmed by gestational diabetes mellitus, resulting in cell-specific barrier function changes

AIMS/HYPOTHESIS

An adverse intrauterine environment can result in permanent changes in the physiology of the offspring and predispose to diseases in adulthood. One such exposure, gestational diabetes mellitus (GDM), has been linked to development of metabolic disorders and cardiovascular disease in offspring. Epigenetic variation, including DNA methylation, is recognised as a leading mechanism underpinning fetal programming and we hypothesised that this plays a key role in fetoplacental endothelial dysfunction following exposure to GDM. Thus, we conducted a pilot epigenetic study to analyse concordant DNA methylation and gene expression changes in GDM-exposed fetoplacental endothelial cells.

METHODS

Genome-wide methylation analysis of primary fetoplacental arterial endothelial cells (AEC) and venous endothelial cells (VEC) from healthy pregnancies and GDM-complicated pregnancies in parallel with transcriptome analysis identified methylation and expression changes. Most-affected pathways and functions were identified by Ingenuity Pathway Analysis and validated using functional assays.

RESULTS

Transcriptome and methylation analyses identified variation in gene expression linked to GDM-associated DNA methylation in 408 genes in AEC and 159 genes in VEC, implying a direct functional link. Pathway analysis found that genes altered by exposure to GDM clustered to functions associated with 'cell morphology' and 'cellular movement' in healthy AEC and VEC. Further functional analysis demonstrated that GDM-exposed cells had altered actin organisation and barrier function.

CONCLUSIONS/INTERPRETATION

Our data indicate that exposure to GDM programs atypical morphology and barrier function in fetoplacental endothelial cells by DNA methylation and gene expression change. The effects differ between AEC and VEC, indicating a stringent cell-specific sensitivity to adverse exposures associated with developmental programming in utero.

DATA AVAILABILITY

DNA methylation and gene expression datasets generated and analysed during the current study are available at the National Center for Biotechnology Information (NCBI) Gene Expression Omnibus (GEO) database ( http://www.ncbi.nlm.nih.gov/geo ) under accession numbers GSE106099 and GSE103552, respectively.

Impaired vasocontractile responses to adenosine in chorionic vessels of human term placenta from pregnant women with pre-existing and gestational diabetes

BACKGROUND

There is clinical and experimental evidence for altered adenosine signalling in the fetoplacental circulation in pregnancies complicated by diabetes, leading to adenosine accumulation in the placenta. However, the consequence for fetoplacental vasocontractility is unclear. This study examined contractility to adenosine of chorionic vessels from type 1 diabetes mellitus, gestational diabetes mellitus and normal pregnancies.

METHODS

Chorionic arteries and veins were isolated from human placenta from normal, gestational diabetes mellitus and type 1 diabetes mellitus pregnancies. Isometric tension recording measured responses to adenosine and the thromboxane A₂ analogue U46619 (thromboxane A₂ mediates fetoplacental vasoconstriction to adenosine). Adenosine and thromboxane prostanoid receptor protein expression was determined by immunoblotting.

RESULTS

Adenosine elicited contractions in chorionic arteries and veins which were impaired in both gestational diabetes mellitus and type 1 diabetes mellitus. Contractions to potassium chloride were unchanged. Adenosine A_2A and A_2B receptor protein levels were not different in gestational diabetes mellitus and normal pregnancies. Contractions to U46619 were unaltered in gestational diabetes mellitus arteries and increased in type 1 diabetes mellitus arteries. Overnight storage of vessels restored contractility to adenosine in gestational diabetes mellitus arteries and normalized contraction to U46619 in type 1 diabetes mellitus arteries.

CONCLUSION

These data are consistent with the concept of aberrant adenosine signalling in diabetes; they show for the first time that this involves impaired adenosine contractility of the fetoplacental vasculature.

Maternal Choline and Betaine Supplementation Modifies the Placental Response to Hyperglycemia in Mice and Human Trophoblasts

Gestational diabetes mellitus (GDM) is characterized by excessive placental fat and glucose transport, resulting in fetal overgrowth. Earlier we demonstrated that maternal choline supplementation normalizes fetal growth in GDM mice at mid-gestation. In this study, we further assess how choline and its oxidation product betaine influence determinants of placental nutrient transport in GDM mice and human trophoblasts. C57BL/6J mice were fed a high-fat (HF) diet 4 weeks prior to and during pregnancy to induce GDM or fed a control normal fat (NF) diet. The HF mice also received 25 mM choline, 85 mM betaine, or control drinking water. We observed that GDM mice had an expanded placental junctional zone with an increased area of glycogen cells, while the thickness of the placental labyrinth zone was decreased at E17.5 compared to NF control mice (p < 0.05). Choline and betaine supplementation alleviated these morphological changes in GDM placentas. In parallel, both choline and betaine supplementation significantly reduced glucose accretion (p < 0.05) in in vitro assays where the human choriocarcinoma BeWo cells were cultured in high (35.5 mM) or normal (5.5 mM) glucose conditions. Expression of angiogenic genes was minimally altered by choline or betaine supplementation in either model. In conclusion, both choline and betaine modified some but not all determinants of placental transport in response to hyperglycemia in mouse and in vitro human cell line models.

Circulatory changes during gestational development of the sheep and human fetus

BACKGROUND

Circulatory changes during gestational development of the human fetus have been considered to be similar to those noted in studies of the lamb fetus.

METHODS

Blood flow measurements derived by Doppler ultrasound and magnetic resonance imaging techniques in human fetuses at various stages of gestation have been compared with those in the lamb.

RESULTS

Combined ventricular output relative to fetal body weight does not change significantly with growth in the lamb or human. However, the proportion of cardiac output to the brain increases markedly in the human, but only slightly in the lamb fetus in the latter half of gestation. Cardiac output distribution to other organs also changes little in the lamb, but in the human, there is a marked decrease in the proportion distributed to the placenta and an increase in pulmonary flow.

CONCLUSION

The developmental changes in the distribution of combined ventricular output in the human fetus may modify the responses to circulatory disturbances, such as congenital cardiovascular malformations, dependent on gestation.

Maternal diabetes alters the development of ductus venosus shunting in the fetus

INTRODUCTION

Despite adequate glycemic control, the risks of fetal macrosomia and perinatal complications are increased in diabetic pregnancies. Adjustments of the umbilical venous distribution, including increased ductus venosus shunting, can be important fetal compensatory mechanisms, but the impact of pregestational diabetes on umbilical venous and ductus venosus flow is not known.

MATERIAL AND METHODS

In this prospective study, 49 women with pregestational diabetes mellitus underwent monthly ultrasound examinations from gestational week 20 to 36. The blood velocity and the mean diameters of the umbilical vein and ductus venosus were used for calculating blood flow volumes. The development of the umbilical venous flow, ductus venosus flow and ductus venosus shunt fraction (% of umbilical venous blood shunted through the ductus venosus) was compared with a reference population, and the effect of HbA_1c on the ductus venosus flow was assessed.

RESULTS

The umbilical venous flow was larger in pregnancies with pregestational diabetes mellitus than in low-risk pregnancies (p < 0.001) but smaller when normalized for fetal weight (p = 0.036). The distributional pattern of the ductus venosus flow developed differently in diabetic pregnancies, particularly during the third trimester, being smaller (p = 0.007), also when normalized for fetal weight (p < 0.001). Correspondingly, the ductus venosus shunt fraction was reduced (p < 0.0001), most prominently at 36 weeks. There were negative relations between the maternal HbA_1c and the ductus venosus flow velocity, flow volume and shunt fraction.

CONCLUSIONS

In pregnancies with pregestational diabetes mellitus, prioritized umbilical venous distribution to the fetal liver and lower ductus venosus shunt capacity reduce the compensatory capability of the fetus and may represent an augmented risk during hypoxic challenges during late pregnancy and birth.

Fetoplacental endothelial exosomes modulate high d-glucose-induced endothelial dysfunction

INTRODUCTION

Gestational diabetes mellitus (GDM) is associated with fetoplacental endothelial dysfunction, which may be induced by hyperglycemia. We hypothesized that endothelial exosomes, which are extracellular nanovesicles affecting endothelial function, play a role in the high glucose (HG)-induced endothelial dysfunction.

METHODS

Exosomes were isolated from HUVECs incubated with basal glucose (5.5 mmol/L; HUVEC- BG; exo-BG) and from HUVECs incubated with HG for 24 h (25 mmol/L; HUVEC-HG; exo-HG) in exosome-free medium. Exosomes were isolated and characterized by ultracentrifugation, sucrose gradient, electron microscopy, nanotracking analysis and Western blotting. HUVEC-BG and HUVEC-HG were exposed to exo-BG and exo-HG in two different concentrations: 5 μg and 1 μg exosome protein/mL. The exosomal effect on endothelial cell function was determined by wound healing assay, expression of endothelial nitric oxide synthase (eNOS), human cationic amino acid transporter type 1 (hCAT-1), vascular endothelial growth factor (VEGF) and intracellular adhesion molecule type 1 (ICAM-1) by Western blotting, qPCR or flow cytometry.

RESULTS

HG increased the exosomal release from HUVECs, endothelial wound healing and expression of phosphorylated (P∼Ser¹¹⁷⁷)-eNOS, hCAT-1, VEGF and ICAM-1. Exo-HG also increased endothelial cell wound healing, P∼Ser¹¹⁷⁷-eNOS, hCAT-1 and ICAM-1 expression in HUVEC-BG. Exo-BG reverted the effect of HG on endothelial cell wound healing and hCAT-1 mRNA expression to normal values.

DISCUSSION

Our results show that HG may induce endothelial dysfunction in HUVECs and that exosomes from HUVEC-HG mimicked some of the effects of HG. This study contributes to the unraveling of the mechanism by which hyperglycemia affects the fetoplacental vasculature in GDM.

Pregestational diabetes increases fetoplacental vascular resistance in rats

INTRODUCTION

Diabetes is a well-known risk factor in pregnancy. Because maternal diabetes involves oxidative stress that is also induced by chronic hypoxia and can alter vascular function, we sought to determine the effects of chronic maternal hyperglycemia on the fetoplacental vasculature in rats and to compare it with the effects of chronic hypoxia.

METHODS

Diabetes was induced in female rats by a streptozotocin injection at a neonatal age. When these animals reached adulthood, their hyperglycemia was confirmed and they were inseminated. Half of them were exposed to hypoxia (10% O₂) for the last week before the delivery. One day before the expected date of delivery, one of their placentae was isolated and perfused.

RESULTS

Fetoplacental vascular resistance was increased equally by experimental diabetes, chronic hypoxia, and their combination. Fetoplacental perfusion pressure-flow analysis suggested increased resistance in the small vessels in chronic hypoxia and in larger vessels in diabetes. Fetal plasma nitrotyrosine levels, measured as a marker of peroxynitrite (reaction product of superoxide and nitric oxide), mirrored the differences in fetoplacental resistance, suggesting a causative role. Fetoplacental vasoconstrictor reactivity to acute hypoxic stimuli was reduced similarly in all groups. Fasudil, a strong vasodilator agent, reduced fetoplacental vascular resistance similarly in all groups, suggesting that for the observed differences among the groups, the changes in vascular morphology were more important than variances in vascular tone.

DISCUSSION

Maternal diabetes increases fetoplacental vascular resistance to a similar extent as chronic hypoxia. These stimuli are not additive. Changes in vascular tone are not responsible for these effects.