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

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.

Preliminary metabolomics analysis of placenta in maternal obesity

INTRODUCTION

Metabolomics identifies phenotypical groups with specific metabolic profiles, being increasingly applied to several pregnancy conditions. This is the first preliminary study analyzing placental metabolomics in normal weight (NW) and obese (OB) pregnancies.

METHODS

Twenty NW (18.5 ≤ BMI< 25 kg/m²) and eighteen OB (BMI≥ 30 kg/m²) pregnancies were studied. Placental biopsies were collected at elective caesarean section. Metabolites extraction method was optimized for hydrophilic and lipophilic phases, then analyzed with GC-MS. Univariate and PLS-DA multivariate analysis were applied.

RESULTS

Univariate analysis showed increased uracil levels while multivariate PLS-DA analysis revealed lower levels of LC-PUFA derivatives in the lipophilic phase and several metabolites with significantly different levels in the hydrophilic phase of OB vs NW.

DISCUSSION

Placental metabolome analysis of obese pregnancies showed differences in metabolites involved in antioxidant defenses, nucleotide production, as well as lipid synthesis and energy production, supporting a shift towards higher placental metabolism. OB placentas also showed a specific fatty acids profile suggesting a disruption of LC-PUFA biomagnification. This study can lay the foundation to further metabolomic placental characterization in maternal obesity. Metabolic signatures in obese placentas may reflect changes occurring in the intrauterine metabolic environment, which may affect the development of adult diseases.

Fine-particulate matter (PM2.5), a risk factor for rat gestational diabetes with altered blood glucose and pancreatic GLUT2 expression

Recent studies have shown an intriguing association between air pollution and diabetic risk. This study was to investigate the impact of fine particulate matter (PM2.5) on glucose consequences and pancreas glucose transporter2 (GLUT2) expression in a gestational diabetes mellitus (GDM) rat model. GDM rats were exposed to a low PM2.5 dose during pregnancy. After exposure, interleukin-6 (IL-6) and blood routine tests (BRT) were detected. Pancreas underwent pathologic examination. The levels of pancreatic homogenate glutathione peroxidase (GSH-Px), methane dicarboxylic aldehyde (MDA) and GLUT2 were detected. There were lower maternal body weight gain and fetal weight in the PM2.5 group. Exposure to PM2.5 caused increased absorbed blastocyst number, higher blood mono-nuclear cells (PBMC), platelets and IL-6 levels. The postprandial blood glucose (PBG) was elevated at most time points after exposure. The pancreas of PM2.5 exposed rats revealed periductal inflammation under pathological examination. The pancreatic GSH-Px significantly reduced and MDA increased in exposed group. The pancreatic GLUT2 expression was decreased after PM2.5 exposure. Our study provides direct evidence that PM2.5 exposure can result in pancreatic pathological changes and glycemic consequences in GDM rats. The oxidative response and inflammation are involved in PM2.5 increased risk of pancreatic impairment and glycemic consequences.

Fetal thymus size in pregnant women with diabetic diseases

AIM

The aim of our study was to assess fetal thymus size in diabetic pregnancies compared with normal pregnancies.

METHODS

Sonographic fetal thymus size was retrospectively assessed in 161 pregnancies with maternal diabetes and in 161 uncomplicated pregnancies matched by gestational age. The anteroposterior thymic and the intrathoracic mediastinal diameter were measured and the quotient was calculated [thymic-thoracic ratio (TT-ratio)]. In addition, we defined the quotient of the anteroposterior thymic diameter and the head circumference as thymus-head ratio (TH-ratio). The maternal diabetes cases were subdivided into three groups: (1) diet-controlled gestational diabetes, (2) insulin-dependent gestational diabetes and (3) preexisting maternal diabetes.

RESULTS

TT-ratio and TH-ratio were smaller in pregnancies with maternal diabetes (P<0.001 and P<0.001, respectively). In all three maternal diabetes subgroups, the TT-ratio and the TH-ratio were lower compared with the control group (P<0.001 for each group).

CONCLUSIONS

Reduced fetal thymus size seems to be associated with diabetic pregnancy. We introduce fetal thymus size as a new potential prognostic parameter for maternal diabetes.

Mitochondrial content and hepcidin are increased in obese pregnant mothers

OBJECTIVE

Maternal obesity is characterized by systemic low-grade inflammation and oxidative stress (OxS) with the contribution of fetal sex dimorphism. We recently described increased mitochondrial content (mtDNA) in placentas of obese pregnancies. Here, we quantify mtDNA and hepcidin as indexes of OxS and systemic inflammation in the obese maternal circulation.

METHODS

Forty-one pregnant women were enrolled at elective cesarean section: 16 were normal weight (NW) and 25 were obese (OB). Obese women were further classified according to the presence/absence of maternal gestational diabetes mellitus (GDM); [OB/GDM(-)]: n = 15, [OB/GDM(+)]: n = 10. mtDNA and hepcidin were evaluated in blood (real-time PCR) and plasma (ELISA).

RESULTS

mtDNA and hepcidin levels were significantly increased in OB/GDM(-) versus NW, significantly correlating with pregestational BMI. Male/female (M/F) ratio was equal in study groups, and overall F-carrying pregnancies showed significantly higher mtDNA and hepcidin levels than M-carrying pregnancies both in obese and normal weight mothers.

CONCLUSIONS

Our results indicate a potential compensatory mechanism to increased obesity-related OxS and inflammation, indicated by the higher hepcidin levels found in obese mothers. Increased placental mitochondrial biogenesis, due to lipotoxic environment, may account for the greater mtDNA amount released in maternal circulation. This increase is namely related to F-carrying pregnancies, suggesting a gender-specific placental response.

Fine particulate matter (PM2.5), a risk factor of rat gestational diabetes with altered blood glucose and pancreatic GLUT2 expression

Recent studies have shown an association between air pollution and diabetic risk. This study was to investigate the impact of fine particulate matter (PM2.5) on glucose consequences and pancreas glucose transporter 2 (GLUT2) expression and its related mechanisms in a gestational diabetes mellitus (GDM) rat model. GDM rats were exposed to a low PM2.5 dose while the controls received saline. Interleukin-6 (IL-6) and blood routine tests (BRT) were detected for analyzing coagulation and inflammation. Pancreas tissues underwent pathologic examination, the levels of homogenate glutathione peroxidase (GSH-Px), and methane dicarboxylic aldehyde (MDA) were detected for oxidative stress estimation, and the degree of GLUT2 expression of pancreas was analyzed. There were lower maternal body weight gain and fetal weight in the PM2.5 group. Exposure to PM2.5 caused increased absorbed blastocyst number and postprandial blood glucose (PBG) blood mono-nuclear cells (PBMC), platelets, and IL-6 levels. The pancreas of PM2.5 exposed rats revealed inflammation under pathological examination. The pancreatic GSH-Px significantly reduced and MDA increased and GLUT2 protein expression decreased after exposure. Our study provides direct evidence that PM2.5 exposure can result in glycemic consequences in GDM rats. The oxidative response and inflammation are involved in PM2.5 increased risk of adverse maternal and fetal consequences.

GDM alters paracrine regulation of feto-placental angiogenesis via the trophoblast

Feto-placental angiogenesis and vascular development are tightly regulated by pro- and anti-angiogenic factors. Villous trophoblast may be a major source of these factors. It forms the classical placental barrier between mother and fetus, and is thus exposed to maternal influences as well. Metabolic and hormonal derangements in gestational diabetes mellitus (GDM) affect feto-placental angiogenesis and vascular growth. Here we hypothesized that GDM alters the trophoblast secretome, which will modulate the paracrine regulation of feto-placental angiogenesis. Primary term trophoblasts were isolated from normal (n=6) and GDM (n=6) pregnancies. Trophoblast conditioned medium (CM) was used to investigate paracrine effects of normal and GDM-exposed trophoblasts on feto-placental endothelial cells (fpECs; n=7), using functional assays for 2D network formation, wound healing, chemotaxis, and proliferation. Gene expression of 23 pro- and anti-angiogenic factors was analyzed. Four trophoblast-derived paracrine regulators of angiogenesis were specifically measured in CM. CM from GDM trophoblasts increased 2D network formation of fpEC by 2.4-fold (P<0.001), whereas wound healing was attenuated by 1.8-fold (P=0.02) and chemo-attraction to the CM was reduced by 33±9% (P=0.02). The effect of CM on proliferation was unchanged between normal and GDM trophoblasts. Expression analysis of pro- and anti-angiogenic molecules in normal and GDM trophoblasts revealed significant differences in ANGPT2, HGF, KISS1 and PLGF expression. Analysis of secreted proteins demonstrated reduced pigment epithelium derived factor and tumor necrosis factor-α secretion by GDM trophoblasts. GDM alters the balance of trophoblast derived, angiogenesis modulating paracrine factors. This may contribute to GDM-associated changes in placental angiogenesis and vascular structure.

Oxygen and oxidative stress in the perinatal period

Fetal life evolves in a hypoxic environment. Changes in the oxygen content in utero caused by conditions such as pre-eclampsia or type I diabetes or by oxygen supplementation to the mother lead to increased free radical production and correlate with perinatal outcomes. In the fetal-to-neonatal transition asphyxia is characterized by intermittent periods of hypoxia ischemia that may evolve to hypoxic ischemic encephalopathy associated with neurocognitive, motor, and neurosensorial impairment. Free radicals generated upon reoxygenation may notably increase brain damage. Hence, clinical trials have shown that the use of 100% oxygen given with positive pressure in the airways of the newborn infant during resuscitation causes more oxidative stress than using air, and increases mortality. Preterm infants are endowed with an immature lung and antioxidant system. Clinical stabilization of preterm infants after birth frequently requires positive pressure ventilation with a gas admixture that contains oxygen to achieve a normal heart rate and arterial oxygen saturation. In randomized controlled trials the use high oxygen concentrations (90% to 100%) has caused more oxidative stress and clinical complications that the use of lower oxygen concentrations (30-60%). A correlation between the amount of oxygen received during resuscitation and the level of biomarkers of oxidative stress and clinical outcomes was established. Thus, based on clinical outcomes and analytical results of oxidative stress biomarkers relevant changes were introduced in the resuscitation policies. However, it should be underscored that analysis of oxidative stress biomarkers in biofluids has only been used in experimental and clinical research but not in clinical routine. The complexity of the technical procedures, lack of automation, and cost of these determinations have hindered the routine use of biomarkers in the clinical setting. Overcoming these technical and economical difficulties constitutes a challenge for the immediate future since accurate evaluation of oxidative stress would contribute to improve the quality of care of our neonatal patients.

Role of Altered Venous Blood Lactate and HbA1c in Women with Gestational Diabetes Mellitus

INTRODUCTION

Being a mirror image of metabolic syndrome, Gestational Diabetes Mellitus (GDM) is associated with significant maternal and fetal morbidity. Increased blood lactate concentration and alterations of substrate utilization are partly involved in development of insulin resistance in GDM. Fetuses born to such mothers have shown low umbilical vein oxygen saturation and low oxygen content and increased lactate concentrations. These changes may certainly reflect enhanced fetal metabolism as a result of hyperglycaemia and hyperinsulinemia and therefore, these fetuses deserve intense surveillance at term and during delivery. Ideally, HbA1c should be maintained below 5% during their first trimesters and below 6% during third trimester. We planned to investigate GDM women for their HbA1c levels too.

AIM

To know if there is any alteration in blood lactate and/or HbA1c levels and to know if there is any correlation between these two parameters in GDM pregnancies, in comparison with the previous studies which measured lactate in cord blood and placental vessels of GDM women.

MATERIALS AND METHODS

It was a hospital based prospective study on 40 women with gestational diabetes and 40 age-matched normal pregnant women. We analysed the biochemical and metabolic mileau in these women by estimating venous blood lactate and HbA1c levels. We paid special attention to follow them up regarding maternal complications if any and perinatal outcomes. The independent samples t-test and Pearson's correlation test were applied.

RESULTS

GDM mothers showed significantly higher lactate and HbA1c levels than normal pregnant women, both with p<0.001. Blood pressure and fetal birth weight were also significantly higher in GDM group than Normal Pregnant (NP) group, both with p-values of <0.001. Further, this increased lactate levels showed significant positive correlation with HbA1c, blood pressure and fetal birth weight.

CONCLUSION

Maternal blood lactate and HbA1c levels have a significant role to play in determining the metabolic mileau of both mother and fetus and thus, their obstetric and general health outcomes.

Developmental origins of NAFLD: a womb with a clue

Changes in the maternal environment leading to an altered intrauterine milieu can result in subtle insults to the fetus, promoting increased lifetime disease risk and/or disease acceleration in childhood and later in life. Particularly worrisome is that the prevalence of NAFLD is rapidly increasing among children and adults, and is being diagnosed at increasingly younger ages, pointing towards an early-life origin. A wealth of evidence, in humans and non-human primates, suggests that maternal nutrition affects the placenta and fetal tissues, leading to persistent changes in hepatic metabolism, mitochondrial function, the intestinal microbiota, liver macrophage activation and susceptibility to NASH postnatally. Deleterious exposures in utero include fetal hypoxia, increased nutrient supply, inflammation and altered gut microbiota that might produce metabolic clues, including fatty acids, metabolites, endotoxins, bile acids and cytokines, which prime the infant liver for NAFLD in a persistent manner and increase susceptibility to NASH. Mechanistic links to early disease pathways might involve shifts in lipid metabolism, mitochondrial dysfunction, pioneering gut microorganisms, macrophage programming and epigenetic changes that alter the liver microenvironment, favouring liver injury. In this Review, we discuss how maternal, fetal, neonatal and infant exposures provide developmental clues and mechanisms to help explain NAFLD acceleration and increased disease prevalence. Mechanisms identified in clinical and preclinical models suggest important opportunities for prevention and intervention that could slow down the growing epidemic of NAFLD in the next generation.

Placental Nutrient Transport in Gestational Diabetic Pregnancies

Maternal obesity during pregnancy is rising and is associated with increased risk of developing gestational diabetes mellitus (GDM), defined as glucose intolerance first diagnosed in pregnancy (1). Fetal growth is determined by the maternal nutrient supply and placental nutrient transfer capacity. GDM-complicated pregnancies are more likely to be complicated by fetal overgrowth or excess adipose deposition in utero. Infants born from GDM mothers have an increased risk of developing cardiovascular and metabolic disorders later in life. Diverse factors, such as ethnicity, age, fetal sex, clinical treatment for glycemic control, gestational weight gain, and body mass index among others, represent a challenge for studying underlying mechanisms in GDM subjects. Determining the individual roles of glucose intolerance, obesity, and other factors on placental function and fetal growth remains a challenge. This review provides an overview of changes in placental macronutrient transport observed in human pregnancies complicated by GDM. Improved knowledge and understanding of the alterations in placenta function that lead to pathological fetal growth will allow for development of new therapeutic interventions and treatments to improve pregnancy outcomes and lifelong health for the mother and her children.

Towards national comprehensive gestational diabetes screening - consequences for neonatal outcome and care

INTRODUCTION

The change from risk-factor-based to nearly comprehensive screening of gestational diabetes (GDM) identifies more but milder cases of the disease. The main aim of this study was to evaluate the effect of this screening policy change on neonatal outcomes and care.

MATERIAL AND METHODS

A population-based register study in Finland. GDM cases during risk-factor-based (year 2006, n = 5179) and comprehensive (2010, n = 6679) screenings were identified through the Medical Birth Register. All singletons without maternal GDM or prepregnancy diabetes served as controls (n = 51 746 and n = 52 386, respectively). The main outcomes were macrosomia, neonatal hypoglycemia and the need for care in a neonatal ward.

RESULTS

In the GDM group, the mean birthweight decreased between the study years from 3660 g to 3595 g and the prevalence of macrosomia from 5.6 to 4.1% even after adjustment for maternal age, parity and prepregnancy body mass index. The adjusted mean difference in birthweight between GDM and control newborns decreased from 70 to 22 g between the study years. The prevalence of neonatal hypoglycemia increased from 18.0 to 22.1% in the GDM group. However, neonatal hypoglycemia was more often treated without care in a neonatal ward. The proportion of infants treated on a neonatal ward decreased in both the GDM and control groups between the study years.

CONCLUSIONS

In newborns, comprehensive GDM screening led to decreased mean birthweight and macrosomia rates, but the prevalence of neonatal hypoglycemia increased. This places substantial demands for delivery hospitals and healthcare resources.

Placental endoplasmic reticulum stress in gestational diabetes: the potential for therapeutic intervention with chemical chaperones and antioxidants

AIMS/HYPOTHESIS

The aim of this work was to determine whether placental endoplasmic reticulum (ER) stress may contribute to the pathophysiology of gestational diabetes mellitus (GDM) and to test the efficacy of chemical chaperones and antioxidant vitamins in ameliorating that stress in a trophoblast-like cell line in vitro.

METHODS

Placental samples were obtained from women suffering from GDM and from normoglycaemic controls and were frozen immediately. Women with GDM had 2 h serum glucose levels > 9.0 mmol/l following a 75 g oral glucose tolerance test and were treated with diet and insulin when necessary. Western blotting was used to assess markers of ER stress. To test the effects of hyperglycaemia on the generation of ER stress, a new trophoblast-like cell line, BeWo-NG, was generated by culturing in a physiological glucose concentration of 5.5 mmol/l (over 20 passages) before challenging with 10 or 20 mmol/l glucose.

RESULTS

All GDM patients were well-controlled (HbA1c 5.86 ± 0.55% or 40.64 ± 5.85 mmol/mol, n = 11). Low-grade ER stress was observed in the placental samples, with dilation of ER cisternae and increased phosphorylation of eukaryotic initiation factor 2 subunit α. Challenge of BeWo-NG with high glucose activated the same pathways, but this was as a result of acidosis of the culture medium rather than the glucose concentration per se. Addition of chemical chaperones 4-phenylbutyrate and tauroursodeoxycholic acid and vitamins C and E ameliorated the ER stress.

CONCLUSIONS/INTERPRETATION

This is the first report of placental ER stress in GDM patients. Chemical chaperones and antioxidant vitamins represent potential therapeutic interventions for GDM.

Expressions of VEGF-A and VEGFR-2 in placentae from GDM pregnancies

BACKGROUND

Gestational diabetes mellitus (GDM) is one of the most common medical complications of pregnancy, and has important health implications for mother and child. Changes in the fetoplacental vessels may predict those in the vasculature of the developing fetus, as these have been implicated in the pathogenesis of human GDM. This study aimed to determine the differences in the localization and expression level of VEGFA and VEGFR2 between placentas of women with GDM and placentas of normal pregnancies, which is the first step in elucidating the possible roles of VEGFA and VEGFR2 in the altered uteroplacental function resulting from maternal hyperglycaemia and ultimately in the manifestation of GDM.

METHODS

The expressions of VEGFA and VEGFR2 mRNA and protein in 20 samples from each group were analyzed by real-time PCR, immunohistochemistry and Western blot. The placental blood barrier and angiogenesis were observed by the transmission electron microscopy (TEM) in10 GDM samples and ten controls.

RESULTS

The expression levels of VEGFA and VEGFR2 mRNA and protein were significantly decreased in the GDM group (P < 0.05 or 0.01). Immunohistochemical analysis showed the reduced expression of VEGFA and VEGFR2 protein in GDM-affected placental tissues, and the degenerative alterations of the terminal villi vascular.

CONCLUSION

The expressions of VEGFA and VEGFR-2 mRNAs and protein were reduced in GDM-affected placental tissues, suggesting that maternal GDM affects the pathophysiological function of placentas.

Placental origins of adverse pregnancy outcomes: potential molecular targets: an Executive Workshop Summary of the Eunice Kennedy Shriver National Institute of Child Health and Human Development

Although much progress is being made in understanding the molecular pathways in the placenta that are involved in the pathophysiology of pregnancy-related disorders, a significant gap exists in the utilization of this information for the development of new drug therapies to improve pregnancy outcome. On March 5-6, 2015, the Eunice Kennedy Shriver National Institute of Child Health and Human Development of the National Institutes of Health sponsored a 2-day workshop titled Placental Origins of Adverse Pregnancy Outcomes: Potential Molecular Targets to begin to address this gap. Particular emphasis was given to the identification of important molecular pathways that could serve as drug targets and the advantages and disadvantages of targeting these particular pathways. This article is a summary of the proceedings of that workshop. A broad number of topics were covered that ranged from basic placental biology to clinical trials. This included research in the basic biology of placentation, such as trophoblast migration and spiral artery remodeling, and trophoblast sensing and response to infectious and noninfectious agents. Research findings in these areas will be critical for the formulation of the development of future treatments and the development of therapies for the prevention of a number of pregnancy disorders of placental origin that include preeclampsia, fetal growth restriction, and uterine inflammation. Research was also presented that summarized ongoing clinical efforts in the United States and in Europe that has tested novel interventions for preeclampsia and fetal growth restriction, including agents such as oral arginine supplementation, sildenafil, pravastatin, gene therapy with virally delivered vascular endothelial growth factor, and oxygen supplementation therapy. Strategies were also proposed to improve fetal growth by the enhancement of nutrient transport to the fetus by modulation of their placental transporters and the targeting of placental mitochondrial dysfunction and oxidative stress to improve placental health. The roles of microRNAs and placental-derived exosomes, as well as messenger RNAs, were also discussed in the context of their use for diagnostics and as drug targets. The workshop discussed the aspect of safety and pharmacokinetic profiles of potential existing and new therapeutics that will need to be determined, especially in the context of the unique pharmacokinetic properties of pregnancy and the hurdles and pitfalls of the translation of research findings into practice. The workshop also discussed novel methods of drug delivery and targeting during pregnancy with the use of macromolecular carriers, such as nanoparticles and biopolymers, to minimize placental drug transfer and hence fetal drug exposure. In closing, a major theme that developed from the workshop was that the scientific community must change their thinking of the pregnant woman and her fetus as a vulnerable patient population for which drug development should be avoided, but rather be thought of as a deprived population in need of more effective therapeutic interventions.

A clinical study which relates to a theoretical simulation of the glucose transport in the human placenta under various diabetic conditions

AIMS

To characterize placental glucose delivery under normoglycemic conditions, gestational and pre-gestational diabetes and to relate the clinical data to theoretical predictions.

METHODS

Data from 125 pregnancies: 50 normal gestations and 75 ones with various types of diabetes were collected. In parallel, we formulated a theoretical model for the transport of glucose under various diabetic conditions. Measured glucose blood levels were fed into the theoretical model that predicts glucose supply to the fetus and the results were confronted with measured fetal weights.

RESULTS

Measured fetal weight and computed glucose delivery in gestational diabetic parturients resemble the situation in normal pregnancies. However, pre-gestational diabetes has a major effect as it involves heavier fetuses and enhanced computed glucose fluxes via placental membranes.

CONCLUSIONS

Fetal weight (increased in pre-gestational and unaltered in gestational diabetes) correlates with the predicted rate of glucose delivery through the placenta.

Insulin Is a Key Modulator of Fetoplacental Endothelium Metabolic Disturbances in Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is a disease of the mother that associates with altered fetoplacental vascular function. GDM-associated maternal hyperglycaemia result in fetal hyperglycaemia, a condition that leads to fetal hyperinsulinemia and altered L-arginine transport and synthesis of nitric oxide, i.e., endothelial dysfunction. These alterations in the fetoplacental endothelial function are present in women with GDM that were under diet or insulin therapy. Since these women and their newborn show normal glycaemia at term, other factors or conditions could be altered and/or not resolved by restoring normal level of circulating D-glucose. GDM associates with metabolic disturbances, such as abnormal handling of the locally released vasodilator adenosine, and biosynthesis and metabolism of cholesterol lipoproteins, or metabolic diseases resulting in endoplasmic reticulum stress and altered angiogenesis. Insulin acts as a potent modulator of all these phenomena under normal conditions as reported in primary cultures of cells obtained from the human placenta; however, GDM and the role of insulin regarding these alterations in this disease are poorly understood. This review focuses on the potential link between insulin and endoplasmic reticulum stress, hypercholesterolemia, and angiogenesis in GDM in the human fetoplacental vasculature. Based in reports in primary culture placental endothelium we propose that insulin is a factor restoring endothelial function in GDM by reversing ERS, hypercholesterolaemia and angiogenesis to a physiological state involving insulin activation of insulin receptor isoforms and adenosine receptors and metabolism in the human placenta from GDM pregnancies.

Placental Nutrient Transport and Intrauterine Growth Restriction

Intrauterine growth restriction refers to the inability of the fetus to reach its genetically determined potential size. Fetal growth restriction affects approximately 5–15% of all pregnancies in the United States and Europe. In developing countries the occurrence varies widely between 10 and 55%, impacting about 30 million newborns per year. Besides having high perinatal mortality rates these infants are at greater risk for severe adverse outcomes, such as hypoxic ischemic encephalopathy and cerebral palsy. Moreover, reduced fetal growth has lifelong health consequences, including higher risks of developing metabolic and cardiovascular diseases in adulthood. Numerous reports indicate placental insufficiency as one of the underlying causes leading to altered fetal growth and impaired placental capacity of delivering nutrients to the fetus has been shown to contribute to the etiology of intrauterine growth restriction. Indeed, reduced expression and/or activity of placental nutrient transporters have been demonstrated in several conditions associated with an increased risk of delivering a small or growth restricted infant. This review focuses on human pregnancies and summarizes the changes in placental amino acid, fatty acid, and glucose transport reported in conditions associated with intrauterine growth restriction, such as maternal undernutrition, pre-eclampsia, young maternal age, high altitude and infection.

Keap1-Nrf2 regulated redox signaling in utero: Priming of disease susceptibility in offspring

Intrauterine exposure to gestational diabetes, pre-eclampsia or intrauterine growth restriction alters the redox status of the developing fetus. Such pregnancy-related diseases in most cases do not have a readily identifiable genetic cause, and epigenetic 'priming' mechanisms in utero may predispose both mother and child to later-life onset of cardiovascular and metabolic diseases. The concept of 'fetal programing' or 'developmental priming' and its association with an increased risk of disease in childhood or adulthood has been reviewed extensively. This review focuses on adaptive changes in the in utero redox environment during normal pregnancy and the consequences of alterations in redox control associated with pregnancies characterized by oxidative stress. We evaluate the evidence that the Keap1-Nrf2 pathway is important for protecting the fetus against adverse conditions in utero and may itself be subject to epigenetic priming, potentially contributing to an increased risk of vascular disease and insulin resistance in later life.

Labor and neonatal outcomes after term induction of labor in gestational diabetes

OBJECTIVE

To identify the optimal gestational age (GA) for induction of labor (IOL) at term among patients with gestational diabetes (GDMA) according to perinatal outcomes.

STUDY DESIGN

The US Natality Database from 2007 to 2010 was reviewed. Inclusion criteria were singleton delivery, IOL at 37 to 42 weeks and GDMA. Exclusion criteria included congenital anomalies, pre-gestational diabetes, hypertensive disorders, previous cesarean, breech presentation and rupture of membranes. Controls were non-GDMA cases delivered in geographic and temporal proximity. Delivery mode, macrosomia and perinatal complications were analyzed. Logistic regression adjusted for confounders was used to calculate odds ratios by GA using 39 weeks non-GDMA as reference.

RESULTS

In all, 96,964 cases and 176,079 controls were included. Increased risk for all adverse outcomes among GDMA cases was found. The nadir for intrapartum and neonatal complications was 38 and 40 weeks, respectively, whereas for cesarean and macrosomia was 39 weeks.

CONCLUSION

The optimal timing for IOL at term in GDMA appears to be 39 to 40 weeks.

Increased adrenergic signaling is responsible for decreased glucose-stimulated insulin secretion in the chronically hyperinsulinemic ovine fetus

Insulin may stimulate its own insulin secretion and is a potent growth factor for the pancreatic β-cell. Complications of pregnancy, such as diabetes and intrauterine growth restriction, are associated with changes in fetal insulin concentrations, secretion, and β-cell mass. However, glucose concentrations are also abnormal in these conditions. The direct effect of chronic fetal hyperinsulinemia with euglycemia on fetal insulin secretion and β-cell mass has not been tested. We hypothesized that chronic fetal hyperinsulinemia with euglycemia would increase glucose-stimulated insulin secretion (GSIS) and β-cell mass in the ovine fetus. Singleton ovine fetuses were infused with iv insulin to produce high physiological insulin concentrations, or saline for 7-10 days. The hyperinsulinemic animals also received a direct glucose infusion to maintain euglycemia. GSIS, measured at 133 ± 1 days of gestation, was significantly attenuated in the hyperinsulinemic fetuses (P < .05). There was no change in β-cell mass. The hyperinsulinemic fetuses also had decreased oxygen (P < .05) and higher norepinephrine (1160 ± 438 vs 522 ± 106 pg/mL; P < .005). Acute pharmacologic adrenergic blockade restored GSIS in the hyperinsulinemic-euglycemic fetuses, demonstrating that increased adrenergic signaling mediates decreased GSIS in these fetuses.

Are there any relationships between umbilical artery Pulsatility Index and macrosomia in fetuses of type I diabetic mothers?

OBJECTIVE

To establish whether there are relationships between umbilical artery Pulsatility Index (PI) and fetal macrosomia in pregnancies complicated by type I diabetes.

METHODS

In a retrospective observational study, 102 singleton pregnant women with type I diabetes were considered. Umbilical artery PI was measured by Doppler ultrasonography within one week from delivery and related to neonatal weight. Pregnancies were grouped according to birtweight in macrosomic group (≥4000 g) and normal growth group (<4000 g). Relationships between umbilical artery PI and birth weight and birth weight centile were tested by Pearson's correlation analysis. Further umbilical artery PI values were compared between macrosomic and normally grown fetuses.

RESULTS

Birth weight was ≥4000 g in 24 pregnancies (23.5%). A significant relationship was found between umbilical artery PI and neonatal weight (r = 0.512; p < 0.01) and neonatal weight centile (r = 0.400; p < 0.01). Umbilical artery PI were significantly lower (t = -6.013; p < 0.001) in the macrosomic group (0.78; 95% confidence interval (CI) 0.73-0.84) than in the normal growth group (1.00; 95% CI 0.97-1.04).

CONCLUSIONS

In pregnancies complicated by type I diabetes there is a significant relationship between umbilical artery PI value before delivery and absolute birth weight and birth weight centile. Macrosomic fetuses show a significant reduction in umbilical artery PI when compared with diabetic pregnancies without fetal overgrowth.

Gestational Diabetes: Long-Term Central Nervous System Developmental and Cognitive Sequelae

Gestational diabetes is a common complication of pregnancy and occurs in approximately 7% of all pregnancies. It has been associated with an increased rate of congenital anomalies including disturbances of intrauterine growth, delayed brain maturity, and neurobehavioral abnormalities in the offspring. The resulting maternal and fetal metabolic dysfunction leads to diminished iron stores (which can affect red blood cell [RBC] production and subsequent organogenesis), a metabolism-placental perfusion mismatch, increased FFA, increased lactic acidosis, and potential hypoxia. Though most newborns born in the context of gestational diabetes are not significantly affected by it, empirical research suggests gestational diabetes has been associated with lower general intelligence, language impairments, attention weaknesses, impulsivity, and behavioral problems. In extreme cases, it may essentially function as a gestational brain insult. Children who are exposed to poorly controlled gestational diabetes may benefit from some form of tracking or follow-up assessments. Additionally, clinicians evaluating children with developmental learning or cognitive dysfunction may want to seek appropriate gestational diabetes-related information from the parents. A greater understanding of this significant gestational risk may help foster improved prenatal diabetes management and may help reduce the neurodevelopmental effects of gestational diabetes.

Glucose, insulin, and oxygen interplay in placental hypervascularisation in diabetes mellitus

The placental vasculature rapidly expands during the course of pregnancy in order to sustain the growing needs of the fetus. Angiogenesis and vascular growth are stimulated and regulated by a variety of growth factors expressed in the placenta or present in the fetal circulation. Like in tumors, hypoxia is a major regulator of angiogenesis because of its ability to stimulate expression of various proangiogenic factors. Chronic fetal hypoxia is often found in pregnancies complicated by maternal diabetes as a result of fetal hyperglycaemia and hyperinsulinemia. Both are associated with altered levels of hormones, growth factors, and proinflammatory cytokines, which may act in a proangiogenic manner and, hence, affect placental angiogenesis and vascular development. Indeed, the placenta in diabetes is characterized by hypervascularisation, demonstrating high placental plasticity in response to diabetic metabolic derangements. This review describes the major regulators of placental angiogenesis and how the diabetic environment in utero alters their expression. In the light of hypervascularized diabetic placenta, the focus was placed on proangiogenic factors.

Gestational diabetes as one of the "great obstetrical syndromes"--the maternal, placental, and fetal dialog

Gestational diabetes mellitus (GDM)-associated fetal and neonatal adverse outcome results from the metabolic milieu projected on the fetus via the placental interface. Therefore, it can be considered to be one of the great obstetrical syndromes. Placentas from GDM pregnancies differ from nondiabetic pregnancies by an increased placental to fetal ratio and by histological findings such as villous fibrinoid necrosis, villous immaturity, chorangiosis, and ischemic changes. While early onset diabetes is more associated with marked structural changes of the placenta, GDM that rises at late gestation is associated more with placental functional changes. These placental changes, causing increased intervillous diffusion distance of immature villi and placental size to perfusion mismatch, may predispose the fetus to chronic and acute changes in gas and nutrient exchange thus turning the placenta from being a "fetus protector" to a potential source of adverse outcome. Understanding placental changes and how they affect outcome is necessary in order to develop effective screening, prevention, and management approaches.

Reduced apoptosis in term placentas from gestational diabetic pregnancies

Gestational diabetic mellitus (GDM) pregnancies have an increased risk of macrosomic infants and large placental mass, though the mechanisms explaining each of these is uncertain. We sought to evaluate the contribution of apoptosis to placental size and the expression of glucose transporters (SLC2A) in GDM pregnancies. Maternal age and pre-pregnancy body weight were documented. Newborn weights were recorded after delivery. Placentas 37-40-week gestation from control patients (no pregnancy complication) (n = 5), or with GDM (n = 5) were weighed immediately after delivery. Villous samples (4 mm diameter) were collected and divided into specimens; one was fixed in 4% paraformaldehyde for immunostaining using terminal deoxynucleotidyl transferase dUTP-mediated nick-end labeling (TUNEL) and activated caspase-3. The other specimen was snap frozen in liquid nitrogen and stored at -80°C for active caspase-3, poly(ADP-ribose) polymerase (PARP), SLC2A1 and SLC2A3 gene expression analysis. Our results showed that maternal age and pre-pregnancy body weight were significantly higher in the GDM group when compared with those from the controls (P < 0.05). The mean neonatal birth weight and placenta weight were significantly higher in the GDM group compared with that from the controls (P < 0.05). The apoptotic index of placentas (0.05 ± 0.01 v. 0.17 ± 0.04, P < 0.04), active caspase-3 polypeptide fragments and PARP protein were significantly decreased in GDM placentas as compared with controls. Further, the level of placental SLC2A1 protein expression was ∼3-fold higher in GDM placentas. Our results suggest that reduced apoptosis in GDM placentas may contribute to increased placental tissue, which together with enhanced SLC2A1 expression, could play a role in fetal macrosomia.

Obstetric conditions and the placental weight ratio

INTRODUCTION

To elucidate how obstetric conditions are associated with atypical placental weight ratios (PWR)s in infants born: (a) ≥37 weeks gestation; (b) at ≥33 but <37 weeks gestation; and (c) <33 weeks gestation.

METHODS

The study included all in-hospital singleton births in London, Ontario between June 1, 2006 and March 31, 2011. PWR was assessed as <10th or >90th percentile by gestational age-specific local population standards. Multivariable analysis was carried out using multinomial logistic regression with blockwise variable entry in order of temporality.

RESULTS

Baseline factors and maternal obstetric conditions associated with PWR <10th percentile were: increasing maternal height, overweight and obese body mass indexes (BMI), large for gestational age infants, smoking, and gestational diabetes. Obstetric factors associated with PWR >90th percentile were: underweight, overweight and obese BMIs, smoking, preeclampsia, placenta previa, and placental abruption. In particular, indicators of hypoxia and altered placental function were generally associated with elevated PWR at all gestations.

DISCUSSION

An association between obstetric conditions associated with fetal hypoxia and PWR ≥90th percentile was illustrated.

CONCLUSIONS

The multivariable findings suggest that the PWR is similarly increased regardless of the etiology of the hypoxia.

Effects of uncomplicated vaginal delivery and epidural analgesia on fetal arterial acid-base parameters at birth in gestational diabetes

AIM

To investigate the effects of uncomplicated vaginal delivery and epidural analgesia on fetal acid-base parameters in women with gestational diabetes (GDM) compared with controls.

METHODS

A retrospective case-control study of 142 women with gestational diabetes and 284 controls. To evaluate the effect of diabetes and analgesia on acid-base status correcting for potential confounders we used ordered logistic equations including quartiles of fetal arterial acid-base parameters collected at birth as outcomes and categories of diabetes and epidural analgesia as explanatory variables.

RESULTS

In the GDM group cord base deficit (-2.63 mmol/l, interquartile range [IQR]=4.2 to -0.65 mmol/l vs. -1.9 mmol/l, IQR=-3.3 to -0.2 mmol/l, p=0.009, odds ratio (OR)=1.51, 95% confidence interval (CI)=1.04-2.18) was lower and concentration of calcium higher (1.49 mmol/l, IQR=1.42-1.56 mmol/l vs. 1.47 mmol/l, IQR=1.41-1.51 mmol/l, p=0.009, OR=1.69, 95% CI=1.12-2.56) compared with controls. Epidural analgesia in the GDM group was associated with reduced cord concentration of glucose (84.0mg/dl [4.7 mmol/l], IQR=70-103.3mg/dl vs. 92.5mg/dl [5.1 mmol/l], IQR=76.5-121.8 mg/dl, p=0.004), lactate (2.65 mmol/l (IQR=1.80-4.20) vs. 3.70 mmol/l (IQR=2.90-5.55 mmol/l), p=0.002) and less pronounced base deficit (-2.05 mmol/l, IQR=-3.90 to -0.17 mmol/l vs. -2.8, IQR=-5.57 to -1.05 mmol/l, p=0.01, OR=0.7, 95% CI=0.49-0.99).

CONCLUSIONS

In uncomplicated pregnancies and deliveries, well-controlled gestational diabetes mellitus has potentially significant detrimental effects on fetal acid-base status at birth. Epidural analgesia reduces cord arterial glucose and lactates.

Video-EEG recordings in full-term neonates of diabetic mothers: observational study

OBJECTIVE

To determine whether full-term newborn infants of diabetic mothers (IDM) present immature/disorganised EEG patterns in the immediate neonatal period, and whether there was any relationship with maternal glycaemic control.

DESIGN AND SETTING

Cohort study with an incidental sample performed in a tertiary hospital neonatal unit.

PATIENTS

23 IDM and 22 healthy newborns born between 2010 and 2013.

INTERVENTIONS

All underwent video-EEG recording lasting >90 min at 48-72 h of life.

MAIN OUTCOME MEASURES

We analysed the percentage of indeterminate sleep, transient sharp waves per hour and mature-for-gestational age EEG patterns (discontinuity, maximum duration of interburst interval (IBI), asynchrony, asymmetry, δ brushes, encoches frontales and α/θ rolandic activity). The group of IDM was divided into two subgroups according to maternal HbA1c: (1) HbA1c≥6% and (2) HbA1c<6%.

RESULTS

Compared with healthy newborns, IDM presented significantly higher percentage of indeterminate sleep (57% vs 25%; p<0.001), discontinuity (2.5% vs 0%; p=0.044) and δ brushes in the bursts (6% vs 3%; p=0.024); higher duration of IBI (0.3 s vs 0 s; p=0.017); fewer encoches frontales (7/h vs 35/h; p<0.001), reduced θ/α rolandic activity (3/h vs 9/h; p<0.001); and more transient sharp waves (25/h vs 5/h; p<0.001). IDM with maternal HbA1c≥6% showed greater percentage of δ brushes in the burst (14% vs 4%; p=0.007).

CONCLUSIONS

Full-term IDM newborns showed video-EEG features of abnormal development of brain function. Maternal HbA1c levels<6% during pregnancy could minimise the risk of cerebral dysmaturity.

Differences in post-mortem findings after stillbirth in women with and without diabetes

AIMS

The reason for the fivefold increased risk of stillbirth in women with diabetes is not known. Further understanding of the underlying mechanisms may facilitate identification of pregnancies at increased risk. We have compared post-mortem reports in matched pairs of stillbirths in women with and without diabetes.

METHODS

Post-mortem reports were provided by the Centre for Maternal and Child Enquiries. Stillbirths as a result of lethal congenital and genetic abnormalities were excluded. Whole body, placenta and organ weights and histo-pathological findings in cases and controls were compared and also related to published reference values.

RESULTS

We analysed post-mortem reports on 23 matched pairs of stillbirths from 2009 to 2010. Mean placental weight in women with diabetes was 75 g less than in control subjects (95% CI -143 to -7 g; P = 0.032). In maternal diabetes, the thymus was often small and showed a 'starry sky' pattern on histology in 11 of 20 cases compared with four of 22 controls (P = 0.03). This histological finding was associated with a particularly low mean placental weight z-score -2.1 (1.1) standard deviations below a reference population corrected for gestational age.

CONCLUSIONS

In over half of the stillbirths occurring in women with diabetes, there was a 'starry sky' appearance in the fetal thymus on histology, this being associated with a small placenta. These findings are consistent with a critical subacute metabolic disturbance being a prominent cause of the increased risk of stillbirth in pregnancies complicated by maternal diabetes.

Racial and ethnic health disparities in reproductive medicine: an evidence-based overview

Racial and ethnic health disparities in reproductive medicine exist across the life span and are costly and burdensome to our healthcare system. Reduction and ultimate elimination of health disparities is a priority of the National Institutes of Health who requires reporting of race and ethnicity for all clinical research it supports. Given the increasing rates of admixture in our population, the definition and subsequent genetic significance of self-reported race and ethnicity used in health disparity research is not straightforward. Some groups have advocated using self-reported ancestry or carefully selected single-nucleotide polymorphisms, also known as ancestry informative markers, to sort individuals into populations. Despite the limitations in our current definitions of race and ethnicity in research, there are several clear examples of health inequalities in reproductive medicine extending from puberty and infertility to obstetric outcomes. We acknowledge that socioeconomic status, education, insurance status, and overall access to care likely contribute to the differences, but these factors do not fully explain the disparities. Epigenetics may provide the biologic link between these environmental factors and the transgenerational disparities that are observed. We propose an integrated view of health disparities across the life span and generations focusing on the metabolic aspects of fetal programming and the effects of environmental exposures. Interventions aimed at improving nutrition and minimizing adverse environmental exposures may act synergistically to reverse the effects of these epigenetic marks and improve the outcome of our future generations.

Amniotic fluid oxidative and nitrosative stress biomarkers correlate with fetal chronic hypoxia in diabetic pregnancies

BACKGROUND

In spite of improvement in obstetrical care, pregnancy in women with type 1 diabetes mellitus is associated with increased perinatal morbidity and mortality. Hyperglycemia during pregnancy causes excessive fetal growth and chronic fetal hypoxia as reflected in increased erythropoietin (EPO) levels in amniotic fluid (AF).

OBJECTIVES

We hypothesized that the degree of fetal hypoxia would correlate with fetal oxidative and nitrosative stress as evidenced ty the concentration of specific biomarkers in AF.

MATERIAL AND METHODS

19 pregnant women with type 1 or insulin-treated gestational diabetes mellitus were studied. AF samples were collected and processed for EPO, meta-tyrosine, nitro-tyrosine and 8-hydroxy-2-deoxiguanosine by chemiluminescent immunoassay and high-performance liquid chromatography coupled to tandem mass spectrometry methods, respectively.

RESULTS

The mean (SD) of the last HbA1c concentration before delivery was 7.7% (1.1). Median gestational age was 258 days (range 231-268). Birth weight was 3,868 ± 695 g with a z-score >2 SD in 47% of the cases. A significant correlation was found between the concentrations of AF EPO and meta-tyrosine/phenylalanine ratio (p < 0.001), nitro-tyrosine (p < 0.01) and 8-oxo-dG/2dG ratio (p < 0.001).

CONCLUSIONS

We confirmed that fetuses of type 1 diabetes or insulin-treated gestational diabetes pregnancies experience chronic hypoxia as reflected by increased EPO concentrations in AF near term. Moreover, EPO levels significantly correlated with the concentration of oxidative and nitrosative stress biomarkers in AF. This pro-oxidant status may predispose newborn infants to poor postnatal adaptation and early neonatal complications.

The placenta and gestational diabetes mellitus

By its location between maternal and fetal bloodstreams the human placenta not only handles the materno-fetal transport of nutrients and gases, but may also be exposed to intrauterine conditions adversely affecting placental and fetal development. Such adverse conditions exist in pregnancies complicated by gestational diabetes mellitus (GDM), and have been associated with alterations in placental anatomy and physiology. These alterations are mainly based on changes on the micro-anatomical and/or even molecular level including aberrant villous vascularization, a disbalance of vasoactive molecules, and enhanced oxidative stress. The consequence thereof may be impaired fetal oxygenation and changes in transplacental nutrient supply. Although transplacental glucose flux is flow limited and independent of glucose transporter availability, transport of essential and nonessential amino acids and expression of genes involved in lipid transport and metabolism are significantly affected by GDM.

Biochemical and Physiological Characteristics of Neonates Born to Mothers with Diabetes During Gestation

The aim of this study was to investigate how glucose homeostasis disorders influence biochemical homeostasis and fetal maturation. A prospective randomized study included 102 infants: 31 newborns of mothers with glucose homeostasis disorders (Group I) and 71 newborns of healthy mothers (Group II). In the pregnant women, the mean age, body weight and height, BMI, parity, duration of the disease and the mode of labor were estimated. The following procedures were performed in each newborn infant: physical examination, determination of Apgar score, measurements of birth weight and length, estimation of neurological status, clinical estimation of gestational age, ECG and ultrasonography of the brain, as well as the basic hematologic, biochemical and microbiological analyses. Newborn infants of diabetic pregnancies were small for gestational age and of high birth weight. The levels of Na+, K+and Cl-ions did not show significant differences between the investigated groups, whereas the levels of total Ca and Mg were significantly decreased (2.18±0.59 and 0.65±0.17 mmol/L) (p<0.001) in the investigated group relative to the control group (2.42±0.53 and 0.81±0.09 mmol/L). The newborn infants of diabetic pregnancies presented with significantly decreased values of phosphates, bicarbonates and pH, whereas the difference in total osmolality was not statistically significant. The level of glucose at birth in the infants of diabetic mothers was lower (2.91±0.51 mmol/L) (p<0.001) than in the infants of healthy pregnancies (3.94±0.29 mmol/L). Glycemia lower than 2 mmol/L was recorded in 6.5% of infants of the investigated group. The level of bilirubin was significantly increased (209.71±56.66 mmol/L) (p<0.001) in infants of diabetic mothers compared to those of the healthy ones (155.70±61.14 mmol/L), like the incidence of clinically manifested hyperbilirubinemia. Disorders of maternal glucose homeostasis cause biochemical disorders such as hypoglycemia, hypocalcemia, hyperbilirubinemia, hypomagne semia and are associated with impaired maturation and congenital malformations of the fetus.

Atypical fetal response to the mother's voice in diabetic compared with overweight pregnancies

OBJECTIVE

To characterize fetal spontaneous heart rate changes and movements and auditory-elicited heart rate changes in fetuses in diabetic pregnancies compared with those in uneventful, overweight pregnancies.

METHODS

Spontaneous heart rate and movements and maternal voice-elicited heart rate changes were observed in 46 mother-fetal pairs (n = 14 gestational diabetic and n = 32 overweight prepregnancy) at 36 (±1) weeks gestational age. Fetal heart rate changes, body movements, and breathing movements were observed for 20 minutes while the mother was at rest. Subsequently, each fetus was presented with a 2-minute audio recording of the mother's voice using the following 6-minute procedure: 2 minutes no-voice baseline, 2 minutes voice presentation, and 2 minutes no-voice postvoice period; heart rate was recorded continuously.

RESULTS

There were no differences in spontaneous heart rate changes, body movements, or breathing movements between the 2 groups. Fetuses in the overweight group showed an increase in the heart rate during the playing of their mother's voice, whereas fetuses in the diabetic group showed no response.

CONCLUSIONS

Fetuses in overweight pregnancies responded to the mother's voice with an increase in the heart rate as has been reported previously in uneventful pregnancies. The lack of response to the mother's voice in fetuses in diabetic pregnancies may represent immature neural or auditory system development, an increased sensorineural threshold, and thyroid or iron deficiency.

Placental transport in pregnancy pathologies

The placenta is positioned between the maternal and fetal circulation and hence plays a key role in transporting maternal nutrients to the developing fetus. Fetal growth changes in the 2 most frequent pregnancy pathologies, gestational diabetes mellitus and fetal growth restriction, are predominantly characterized by an exaggerated and restricted fat accretion, respectively. Glucose, by its regulating effect on fetal insulin concentrations, and lipids have been strongly implicated in fetal fat deposition. Transplacental glucose flux is highly efficient and limited only by nutrient availability (flow-limited)--ie, driven by the maternal-fetal glucose concentration gradient and blood flow, with little, if any, effect of placental morphology, glucose consumption, and transporter expression. This explains why, despite changes in these determinants in both pathologies, transplacental glucose flux is unaltered.

Consequences of gestational and pregestational diabetes on placental function and birth weight

Maternal diabetes constitutes an unfavorable environment for embryonic and fetoplacental development. Despite current treatments, pregnant women with pregestational diabetes are at increased risk for congenital malformations, materno-fetal complications, placental abnormalities and intrauterine malprogramming. The complications during pregnancy concern the mother (gravidic hypertension and/or preeclampsia, cesarean section) and the fetus (macrosomia or intrauterine growth restriction, shoulder dystocia, hypoglycemia and respiratory distress). The fetoplacental impairment and intrauterine programming of diseases in the offspring’s later life induced by gestational diabetes are similar to those induced by type 1 and type 2 diabetes mellitus. Despite the existence of several developmental and morphological differences in the placenta from rodents and women, there are similarities in the alterations induced by maternal diabetes in the placenta from diabetic patients and diabetic experimental models. From both human and rodent diabetic experimental models, it has been suggested that the placenta is a compromised target that largely suffers the impact of maternal diabetes. Depending on the maternal metabolic and proinflammatory derangements, macrosomia is explained by an excessive availability of nutrients and an increase in fetal insulin release, a phenotype related to the programming of glucose intolerance. The degree of fetal damage and placental dysfunction and the availability and utilisation of fetal substrates can lead to the induction of macrosomia or intrauterine growth restriction. In maternal diabetes, both the maternal environment and the genetic background are important in the complex and multifactorial processes that induce damage to the embryo, the placenta, the fetus and the offspring. Nevertheless, further research is needed to better understand the mechanisms that govern the early embryo development, the induction of congenital anomalies and fetal overgrowth in maternal diabetes.

Differences in the implications of maternal lipids on fetal metabolism and growth between gestational diabetes mellitus and control pregnancies

AIMS

To evaluate the potential contribution of maternal glucose and lipids to fetal metabolic variables and growth in pregnancies with normal glucose tolerance in comparison with pregnancies with well-controlled gestational diabetes previously reported by us.

METHODS

In 190 pregnancies with normal oral glucose tolerance tests (controls), insulin, glucose and lipid components were determined in maternal and arterial cord blood serum. Birthweight and neonatal fat mass were obtained after delivery. Values were adjusted for maternal pre-pregnancy BMI, Caesarean section and gestational age. Measurements were compared with those of gestational diabetes previously reported.

RESULTS

Maternal serum glucose, triacylglycerol, free fatty acid and cholesterol levels did not differ between control pregnancies and those with gestational diabetes, whereas insulin, homeostasis model assessment and glycerol values were significantly lower in the former (2.6 vs. 5.6 μmol/l and 176 vs. 193 μmol/l, respectively). In contrast, cord blood glucose and free fatty acids were significantly lower in control pregnancies than in those with gestational diabetes (3.9 vs. 4.4 mmol/l and 80.7 vs. 137 μmol/l, respectively); the same was valid for insulin (0.03 vs. 0.05 nmol/l) and homeostasis model assessment (1.0 vs. 1.87). In control pregnancies, maternal serum glucose, free fatty acids and glycerol correlated with those in cord blood, but not with neonatal weight and fat mass, as seen for free fatty acids in those with gestational diabetes. The negative correlation between cord blood triacylglycerols and neonatal weight or fat mass previously reported in gestational diabetes could not be confirmed in control pregnancies, where all fetal lipids showed a positive correlation to neonatal anthropometrics.

CONCLUSION

In normal pregnancies, in contrast to those with gestational diabetes, maternal lipids do not influence neonatal weight. Similar levels of maternal lipids in pregnancies with gestational diabetes and control pregnancies, but higher free fatty acids in the cord blood of those with gestational diabetes, indicate their enhanced placental transport and/or enhanced lipolysis as a result of decreased fetal insulin responsiveness.

Foetal and neonatal complications in gestational diabetes: perinatal mortality, congenital malformations, macrosomia, shoulder dystocia, birth injuries, neonatal complications

OBJECTIVE

To evaluate the risks of perinatal complications in infants born to mothers with treated or untreated gestational diabetes mellitus (GDM).

METHODS

A search of the PubMed database was performed and recommendations from NICE and the French National Authority for Health were consulted.

RESULTS

Untreated moderate or severe GDM increases the risk of foetal and neonatal complications (EL1). The risk of malformations slightly increases in newborns of mothers with GDM compared to the general population (EL2). This risk is probably associated with the presence of undiagnosed type 2 diabetes among patients with GDM (EL2). There is a linear relationship between maternal blood glucose levels and an increased birth weight (EL2). Treatment for GDM reduces the incidence of macrosomia (EL1). Although the risk of cardiomyopathy in cases of GDM cannot be accurately estimated based on the available data, severe clinical forms are rare. The risks of neonatal asphyxia and perinatal mortality are no higher in infants born to women with GDM (EL2). Birth injuries and brachial plexus injuries are rare, and no more likely to occur in cases of untreated GDM. It is difficult to assess the risk of respiratory distress, regardless of its cause. It is not possible to establish a link between GDM and neonatal respiratory problems due to insufficient data. Although the risk of neonatal hypoglycaemia is difficult to determine due to the variable definitions reported in the literature, the incidence of hypoglycaemia requiring intravenous therapy is low (EL1). The risks of hypocalcaemia (EL4) and hyperbilirubinemia (EL1) are similar to the general population.

CONCLUSION

Serious perinatal complications specifically associated with GDM are rare. Macrosomia has been demonstrated to be the predominant adverse outcome in cases of GDM. It is the main factor linked to reported cases of complications in GDM. Maternal obesity is an additional risk factor for complications, regardless of diabetes status.

Fetal exposure to altered amniotic fluid glucose, insulin, and insulin-like growth factor-binding protein 1 occurs before screening for gestational diabetes mellitus

OBJECTIVE

We explored the possibility that perturbations in amniotic fluid glucose, insulin, and insulin-like growth factor-binding protein 1(IGFBP1) and/or metabolic acids exist before routine screening for GDM.

RESEARCH DESIGN AND METHODS

We selected consenting mother-infant pairs (n = 408) who met our inclusion criteria (singleton pregnancy, no genetic abnormalities, and no preexisting diabetes) and for whom sufficient amniotic fluid and appropriate medical information were available. We compared birth outcomes and second trimester amniotic fluid glucose, insulin, IGFBP1 concentrations, and amniotic fluid lactic, β-hydroxybutyric, and uric acids of mothers with gestational diabetes mellitus (GDM) (n = 52) with those of mothers with no diagnosis of GDM at >24 weeks (n = 356).

RESULTS

Higher amniotic fluid glucose, lactic acid, uric acid, and insulin and lower IGFBP1 concentrations were present by 15.1 ± 0.1 weeks in mothers in whom GDM was subsequently diagnosed. However, logistic regression showed that second trimester amniotic fluid glucose, but not insulin, IGFBP1, or metabolic acids was associated with an increased odds ratio (1.2 [95% CI 1.052-1.338]) for diagnosis of GDM at 24-28 weeks. In addition, probability contour maps that accounted for nonlinear relationships among the dynamically changing amniotic fluid constituents showed an increased risk for GDM with elevated second trimester amniotic fluid glucose in combination with either elevated amniotic fluid insulin or low amniotic fluid IGFBP1

CONCLUSIONS

Fetuses are exposed to increased amniotic fluid glucose before 15 weeks of gestation, suggesting that metabolic perturbations are underway before diagnosis and that earlier screening and intervention may be warranted.

Growth of fetal lean mass and fetal fat mass in gestational diabetes

OBJECTIVES

This study was carried out to investigate growth indicators of fetal lean mass and fat mass in the second half of the gestational period in pregnancies complicated by gestational diabetes mellitus (GDM) in comparison to normal control pregnancies.

METHODS

Forty-three control and 171 GDM pregnancies were followed longitudinally by ultrasound examinations, measuring both traditional biometric parameters and six non-traditional parameters for the evaluation of lean and fat mass. A mixed linear model derived from the log-Count function was used to model fetal growth and to make comparisons between groups. Factor analysis was used to evaluate the associations between gestational diabetes and fetal size and fetal fat/lean mass ratios.

RESULTS

A total of 506 scans were obtained in the 214 pregnancies, a mean of 2.4 scans per pregnancy (range 2-5). Maternal age, prepregnancy weight and body mass index were significantly higher in GDM pregnancies. Fetuses of GDM pregnancies showed greater growth, at the same gestational age, for each lean and fat non-traditional parameter, having a significantly greater amount of total tissue mass and a higher fat mass/lean mass ratio, independent of gestational age, in comparison to control pregnancies.

CONCLUSIONS

A non-invasive, repeatable evaluation of fetal body composition in utero could represent a useful method for the early detection of growth abnormalities and for direct estimation of the fetal metabolic status.