Pregestational diabetes induces fetal coronary artery malformation via reactive oxygen species signaling

The Interplay between Mechanoregulation and ROS in Heart Physiology, Disease, and Regeneration

Cardiovascular diseases are currently the most common cause of death in developed countries. Due to lifestyle and environmental factors, this problem is only expected to increase in the future. Reactive oxygen species (ROS) are a key player in the onset of cardiovascular diseases but also have important functions in healthy cardiac tissue. Here, the interplay between ROS generation and cardiac mechanical forces is shown, and the state of the art and a perspective on future directions are discussed. To this end, an overview of what is currently known regarding ROS and mechanosignaling at a subcellular level is first given. There the role of ROS in mechanosignaling as well as the interplay between both factors in specific organelles is emphasized. The consequences at a larger scale across the population of heart cells are then discussed. Subsequently, the roles of ROS in embryogenesis, pathogenesis, and aging are further discussed, exemplifying some aspects of mechanoregulation. Finally, different models that are currently in use are discussed to study the topics above.

Casting Light on The Hidden Prevalence: A Novel Perspective on Hypoplastic Coronary Artery Disease

Background and Objectives: Coronary artery anomalies (CAAs) represent a group of rare cardiac abnormalities with an incidence of up to 1.2%. The aim of this retrospective study was to conduct a comprehensive epidemiological assessment of the prevalence of hypoplastic coronary arteries using coronary computed tomography angiography (CCTA) in patients with diagnosed CAAs and individuals presenting with cardiovascular manifestations in the north-eastern region of Romania. This study was motivated by the limited investigation of the CAAs conducted in this area. Methods: We analyzed data collected from 12,758 coronary computed tomography angiography (CCTA) records available at the "Prof. Dr. George I.M. Georgescu" Cardiovascular Diseases Institute, spanning the years 2012 to 2022. Results: Among 350 individuals with CAAs (2.7% of the total cohort), 71 patients (20.3% of the anomaly presenting group and 0.5% of the entire CCTA cohort) exhibited at least one hypoplastic coronary artery. The mean age of individuals diagnosed with hypoplastic coronary artery disease (HCAD) was 61 years, while the age distribution among them ranged from 22 to 84 years. Nearly equal cases of right and left dominance (33 and 31, respectively) were observed, with only 7 cases of co-dominance. Conclusions: HCAD may be considered underexplored in current published research, despite its potentially significant implications ranging to an increased risk of sudden cardiac arrest. The specific prevalence of HCAD among CAAs might be higher than previously reported, possibly reflecting better diagnostic accuracy of CCTA over classic coronary imaging. The absence of standard diagnostic and therapeutic protocols for HCAD underscores the necessity of a personalized approach for such cases.

Long-term outcomes and potential mechanisms of offspring exposed to intrauterine hyperglycemia

Diabetes mellitus during pregnancy, which can be classified into pregestational diabetes and gestational diabetes, has become much more prevalent worldwide. Maternal diabetes fosters an intrauterine abnormal environment for fetus, which not only influences pregnancy outcomes, but also leads to fetal anomaly and development of diseases in later life, such as metabolic and cardiovascular diseases, neuropsychiatric outcomes, reproduction malformation, and immune dysfunction. The underlying mechanisms are comprehensive and ambiguous, which mainly focus on microbiota, inflammation, reactive oxygen species, cell viability, and epigenetics. This review concluded with the influence of intrauterine hyperglycemia on fetal structure development and organ function on later life and outlined potential mechanisms that underpin the development of diseases in adulthood. Maternal diabetes leaves an effect that continues generations after generations through gametes, thus more attention should be paid to the prevention and treatment of diabetes to rescue the pathological attacks of maternal diabetes from the offspring.

Pregestational Diabetes and Congenital Heart Defects

Studies have consistently shown a significant increase in the risk of congenital heart defects in the offspring of diabetic mothers compared with those of nondiabetic pregnancies. Evidence points that all types of pregestational diabetes have the capacity of generating cardiac malformations in a more accentuated manner than in gestational diabetes, and there seems to be an increased risk for all congenital heart defects phenotypes in the presence of maternal diabetes. Currently, the application of some therapies is under study in an attempt to reduce the risks inherent to diabetic pregnancies; however, it has not yet been possible to fully prove their effectiveness. The present review aims to better understand the mechanisms that govern the association between pregestational diabetes and congenital heart defects and how maternal diabetes interferes with fetal cardiac development, as there is still a long way to go in the investigation of this complex process.

Inhibition of intraflagellar transport protein-88 promotes epithelial-to-mesenchymal transition and reduces cardiac remodeling post-myocardial infarction

The epicardium is a potential source of cardiac progenitors to support reparative angiogenesis after myocardial infarction (MI) through epithelial-to-mesenchymal transition (EMT). Primary cilia are recognized as hubs of cellular signaling, and their presence can alter downstream pathways to modulate EMT. The present study aimed to examine the effects of inhibiting intraflagellar transport protein-88 (Ift88), a protein vital to ciliary assembly, on epicardial EMT and cardiac remodeling post-MI. Epicardium derived cells (EPDCs) were cultured from E13.5 heart explants and treated with adenoviral vector encoding short-hairpin RNA against the mouse Ift88 (Ad-shIft88) to disassemble the primary cilium. Effects of Ad-shIft88 on epicardial EMT and cardiac remodeling were examined in mice post-MI. Our results show that Ad-shIft88 enhanced EMT of cultured EPDCs. In adult mice, intra-myocardial administration of Ad-shIft88 increased the number of Wilms tumor 1 (Wt1) positive cells in the epicardium and myocardium, promoted expression of genes associated with epicardial EMT, and enhanced capillary and arteriolar densities post-MI. Additionally, intra-myocardial Ad-shIft88 treatment attenuated cardiac hypertrophy and improved myocardial function three weeks post-MI. In conclusion, knockdown of Ift88 improves epicardial EMT, neovascularization and cardiac remodeling in the ischemic heart. Our study highlights the primary cilium as a potential therapeutic target post-MI.

Maternal nicotine exposure induces congenital heart defects in the offspring of mice

Maternal cigarette smoking is a risk factor for congenital heart defects (CHDs). Nicotine replacement therapies are often offered to pregnant women following failed attempts of smoking cessation. However, the impact of nicotine on embryonic heart development is not well understood. In the present study, the effects of maternal nicotine exposure (MNE) during pregnancy on foetal heart morphogenesis were studied. Adult female mice were treated with nicotine using subcutaneous osmotic pumps at 0.75 or 1.5 mg/kg/day and subsequently bred with male mice. Our results show that MNE dose-dependently increased CHDs in foetal mice. CHDs included atrial and ventricular septal defects, double outlet right ventricle, unguarded tricuspid orifice, hypoplastic left ventricle, thickened aortic and pulmonary valves, and ventricular hypertrophy. MNE also significantly reduced coronary artery size and vessel abundance in foetal hearts. Moreover, MNE resulted in higher levels of oxidative stress and altered the expression of key cardiogenic regulators in the developing heart. Nicotine exposure reduced epicardial-to-mesenchymal transition in foetal hearts. In conclusion, MNE induces CHDs and coronary artery malformation in mice. These findings provide insight into the adverse outcomes of foetuses by MNE during pregnancy.

Congenital Abnormalities in the Infant of a Diabetic Mother

Diabetes mellitus is among the most common chronic diseases worldwide. Infants of diabetic mothers are at increased risk of having congenital abnormalities. Tremendous progress has been achieved in the pregnancy care of diabetic women; however, the risk of birth defects associated with maternal diabetes still exists. These anomalies might arise in many organs and systems of the developing fetus. Many mechanisms have been implicated in the teratogenicity of maternal diabetes and it is critical to achieve good glycemic control before conception in women with diabetes. Neonatal clinicians must be able to identify patients at risk and recognize the signs of diabetic embryopathy. This article presents a review of congenital anomalies associated with maternal diabetes.

Effect of Corn Silk Aqueous Extract on Brown Adipose Tissue of Embryos and Neonates of Diabetic Pregnant Mice: A Histological Study

Context

Many congenital malformations are seen increasingly, due to diabetic mothers causing a burden on health systems. Corn silk (CS) extract has been used as a natural hypoglycemic treatment. However, its teratogenic safety was not studied.

Aims

Therefore, in this study, we examine the effect of CS aqueous extract on fetuses, offspring of normal and diabetic female mice treated with CS aqueous extract.

Settings and Design

Pregnant female mice were divided into two groups diabetic and nondiabetic. Then, each of these groups was divided into control and treated.

Subjects and Methods

A daily dose of 4 g/kg of CS aqueous extract was given orally to the treated groups, control groups were given distilled water. The collection of samples was at day 16.5 of pregnancy, and neonates. Brown adipose tissue (BAT) in the sections of the preserved sample was examined.

Statistical Analysis Used

BAT areas were measured from 10 samples of each treatment age group in 2 sections. Data were analyzed with one-way ANOVA, then, two-independent sample test (Mann-Whitney) was done to test the significance of differences between groups.

Results

The BAT areas were negatively affected by diabetes and the extract. Both the extract and diabetes caused an increase in fat accumulation in the adipocytes with varying degrees.

Conclusions

This study showed for the first time to our knowledge that the use of CS aqueous extract during pregnancy affected BAT organization and area, and that the used dose did not decrease the malformations caused by diabetes. More studies with different doses should be investigated.

The role of glucose in physiological and pathological heart formation

Cells display distinct metabolic characteristics depending on its differentiation stage. The fuel type of the cells serves not only as a source of energy but also as a driver of differentiation. Glucose, the primary nutrient to the cells, is a critical regulator of rapidly growing embryos. This metabolic change is a consequence as well as a cause of changes in genetic program. Disturbance of fetal glucose metabolism such as in diabetic pregnancy is associated with congenital heart disease. In utero hyperglycemia impacts the left-right axis establishment, migration of cardiac neural crest cells, conotruncal formation and mesenchymal formation of the cardiac cushion during early embryogenesis and causes cardiac hypertrophy in late fetal stages. In this review, we focus on the role of glucose in cardiogenesis and the molecular mechanisms underlying heart diseases associated with hyperglycemia.

Myocardium-Specific Deletion of Rac1 Causes Ventricular Noncompaction and Outflow Tract Defects

Background: Left ventricular noncompaction (LVNC) is a cardiomyopathy that can lead to arrhythmias, embolic events and heart failure. Despite our current knowledge of cardiac development, the mechanisms underlying noncompaction of the ventricular myocardium are still poorly understood. The small GTPase Rac1 acts as a crucial regulator of numerous developmental events. The present study aimed to investigate the cardiomyocyte specific role of Rac1 in embryonic heart development. Methods and Results: The Nkx2.5-Cre transgenic mice were crossed with Rac1^f/f mice to generate mice with a cardiomyocyte specific deletion of Rac1 (Rac1^Nkx2.5) during heart development. Embryonic Rac1^Nkx2.5 hearts at E12.5–E18.5 were collected for histological analysis. Overall, Rac1^Nkx2.5 hearts displayed a bifid apex, along with hypertrabeculation and a thin compact myocardium. Rac1^Nkx2.5 hearts also exhibited ventricular septal defects (VSDs) and double outlet right ventricle (DORV) or overriding aorta. Cardiomyocytes had a rounded morphology and were highly disorganized, and the myocardial expression of Scrib, a planar cell polarity protein, was reduced in Rac1^Nkx2.5 hearts. In addition, cell proliferation rate was significantly decreased in the Rac1^Nkx2.5 ventricular myocardium at E9.5. Conclusions: Rac1 deficiency in the myocardium impairs cardiomyocyte elongation and organization, and proliferative growth of the heart. A spectrum of CHDs arises in Rac1^Nkx2.5 hearts, implicating Rac1 signaling in the ventricular myocardium as a crucial regulator of OFT alignment, along with compact myocardium growth and development.

NOX2 Is Critical to Endocardial to Mesenchymal Transition and Heart Development

NADPH oxidases (NOX) are a major source of reactive oxygen species (ROS) production in the heart. ROS signaling regulates gene expression, cell proliferation, apoptosis, and migration. However, the role of NOX2 in embryonic heart development remains elusive. We hypothesized that deficiency of Nox2 disrupts endocardial to mesenchymal transition (EndMT) and results in congenital septal and valvular defects. Our data show that 34% of Nox2^−/− neonatal mice had various congenital heart defects (CHDs) including atrial septal defects (ASD), ventricular septal defects (VSD), atrioventricular canal defects (AVCD), and malformation of atrioventricular and aortic valves. Notably, Nox2^−/− embryonic hearts show abnormal development of the endocardial cushion as evidenced by decreased cell proliferation and an increased rate of apoptosis. Additionally, Nox2 deficiency disrupted EndMT of atrioventricular cushion explants ex vivo. Furthermore, treatment with N-acetylcysteine (NAC) to reduce ROS levels in the wild-type endocardial cushion explants decreased the number of cells undergoing EndMT. Importantly, deficiency of Nox2 was associated with reduced expression of Gata4, Tgfβ2, Bmp2, Bmp4, and Snail1, which are critical to endocardial cushion and valvoseptal development. We conclude that NOX2 is critical to EndMT, endocardial cushion cell proliferation, and normal embryonic heart development.

Integrated bioinformatics analysis of potential pathway biomarkers using abnormal proteins in clubfoot

Background

As one of the most common major congenital distal skeletal abnormalities, congenital talipes equinovarus (clubfoot) affects approximately one in one thousandth newborns. Although several etiologies of clubfoot have been proposed and several genes have been identified as susceptible genes, previous studies did not further explore signaling pathways and potential upstream and downstream regulatory networks. Therefore, the aim of the present investigation is to explore abnormal pathways and their interactions in clubfoot using integrated bioinformatics analyses.

Methods

KEGG, gene ontology (GO), Reactome (REAC), WikiPathways (WP) or human phenotype ontology (HP) enrichment analysis were performed using WebGestalt, g:Profiler and NetworkAnalyst.

Results

A large number of signaling pathways were enriched e.g. signal transduction, disease, metabolism, gene expression (transcription), immune system, developmental biology, cell cycle, and ECM. Protein-protein interactions (PPIs) and gene regulatory networks (GRNs) analysis results indicated that extensive and complex interactions occur in these proteins, enrichment pathways, and TF-miRNA coregulatory networks. Transcription factors such as SOX9, CTNNB1, GLI3, FHL2, TGFBI and HOXD13, regulated these candidate proteins.

Conclusion

The results of the present study supported previously proposed hypotheses, such as ECM, genetic, muscle, neurological, skeletal, and vascular abnormalities. More importantly, the enrichment results also indicated cellular or immune responses to external stimuli, and abnormal molecular transport or metabolism may be new potential etiological mechanisms of clubfoot.

Maternal Diabetes Mellitus and Persistent Pulmonary Hypertension of the Newborn: Accumulated Evidence From Observational Studies

OBJECTIVES

Maternal diabetes mellitus (including pre-existing and gestational diabetes mellitus) is linked with adverse infant outcomes. However, the question of whether maternal diabetes increases the risk of persistent pulmonary hypertension of the newborn (PPHN) is unclear. Herein, we conducted a systematic review and meta-analysis to summarize clinical evidence to determine the association between maternal diabetes mellitus and PPHN.

METHODS

In this systematic review and meta-analysis, we systematically searched PubMed, Embase, Cochrane Library, Web of Science and Google Scholar to identify relevant studies according to predefined criteria. Data from selected studies were extracted, and meta-analysis was performed using fixed effects modelling.

RESULTS

In all, we included 7 unique studies with aggregated data on 2 million individuals and >5,000 cases of PPHN. Maternal diabetes was significantly associated with a higher risk of PPHN (risk ratio [RR], 1.37; 95% confidence interval [CI], 1.23 to 1.51). Both case-control and cohort studies exhibited that the presence of maternal diabetes increased the risk of PPHN (case-control: RR, 1.91; 95% CI, 1.02 to 2.79; cohort: RR, 1.36; 95% CI, 1.22 to 1.50). By omitting 1 study at a time, sensitivity analysis made sure that no individual study was entirely responsible for the combined results.

CONCLUSIONS

Maternal diabetes was associated with increased risk of PPHN. For babies with refractory hypoxemia, with mothers with diabetes, PPHN should be taken into consideration in clinical practice.

Sapropterin reduces coronary artery malformation in offspring of pregestational diabetes mice

Endothelial nitric oxide synthase (eNOS) and oxidative stress are critical to embryonic coronary artery development. Maternal diabetes increases oxidative stress and reduces eNOS activity in the fetal heart. Sapropterin (Kuvan®) is an orally active, synthetic form of tetrahydrobiopterin (BH4) and a co-factor for eNOS with antioxidant properties. The aim of the present study was to examine the effects of sapropterin on fetal coronary artery development during pregestational diabetes in mice. Diabetes was induced by streptozotocin to adult female C57BL/6 mice. Sapropterin (10 mg/kg/day) was orally administered to pregnant mice from E0.5 to E18.5. Fetal hearts were collected at E18.5 for coronary artery morphological analysis. Sapropterin treatment to diabetic dams reduced the incidence of coronary artery malformation in offspring from 50.0% to 20.6%. Decreases in coronary artery luminal diameter, volume and abundance in fetal hearts from diabetic mothers, were prevented by sapropterin treatment. Maternal diabetes reduced epicardial epithelial-to-mesenchymal transition (EMT) and expression of transcription and growth factors critical to coronary artery development including hypoxia-inducible factor 1a (Hif1a), Snail1, Slug, β-catenin, retinaldehyde dehydrogenase 2 (Aldh1a2), basic fibroblast growth factor (bFGF) and vascular endothelial group factor receptor 2 (Vegfr2) in E12.5 hearts. Additionally, eNOS phosphorylation was lower while oxidative stress was higher in E12.5 hearts from maternal diabetes. Notably, these abnormalities were all restored to normal levels after sapropterin treatment. In conclusion, sapropterin treatment increases eNOS activity, lowers oxidative stress and reduces coronary artery malformation in offspring of pregestational diabetes. Sapropterin may have therapeutic potential in preventing coronary artery malformation in maternal diabetes.

Say NO to ROS: Their Roles in Embryonic Heart Development and Pathogenesis of Congenital Heart Defects in Maternal Diabetes

Congenital heart defects (CHDs) are the most prevalent and serious birth defect, occurring in 1% of all live births. Pregestational maternal diabetes is a known risk factor for the development of CHDs, elevating the risk in the child by more than four-fold. As the prevalence of diabetes rapidly rises among women of childbearing age, there is a need to investigate the mechanisms and potential preventative strategies for these defects. In experimental animal models of pregestational diabetes induced-CHDs, upwards of 50% of offspring display congenital malformations of the heart, including septal, valvular, and outflow tract defects. Specifically, the imbalance of nitric oxide (NO) and reactive oxygen species (ROS) signaling is a major driver of the development of CHDs in offspring of mice with pregestational diabetes. NO from endothelial nitric oxide synthase (eNOS) is crucial to cardiogenesis, regulating various cellular and molecular processes. In fact, deficiency in eNOS results in CHDs and coronary artery malformation. Embryonic hearts from diabetic dams exhibit eNOS uncoupling and oxidative stress. Maternal treatment with sapropterin, a cofactor of eNOS, and antioxidants such as N-acetylcysteine, vitamin E, and glutathione as well as maternal exercise have been shown to improve eNOS function, reduce oxidative stress, and lower the incidence CHDs in the offspring of mice with pregestational diabetes. This review summarizes recent data on pregestational diabetes-induced CHDs, and offers insights into the important roles of NO and ROS in embryonic heart development and pathogenesis of CHDs in maternal diabetes.

Maternal voluntary exercise mitigates oxidative stress and incidence of congenital heart defects in pre-gestational diabetes

Women with pre‐gestational diabetes have a higher risk of producing children with congenital heart defects (CHDs), caused predominantly by hyperglycemia‐induced oxidative stress. In this study, we evaluated if exercise during pregnancy could mitigate oxidative stress and reduce the incidence of CHDs in the offspring of diabetic mice. Female mice were treated with streptozotocin to induce pre‐gestational diabetes, then mated with healthy males to produce offspring. They were also given access to running wheels 1 week before mating and allowed to exercise voluntarily until E18.5. Heart morphology, gene expression, and oxidative stress were assessed in foetal hearts. Maternal voluntary exercise results in a significantly lower incidence of CHDs from 59.5% to 25%. Additionally, diabetes‐induced defects in coronary artery and capillary morphogenesis were also lower with exercise. Myocardial cell proliferation and epithelial‐mesenchymal transition at E12.5 was significantly lower with pre‐gestational diabetes which was mitigated with maternal exercise. Cardiac gene expression of Notch1, Snail1, Gata4 and CyclinD1 was significantly higher in the embryos of diabetic mice that exercised compared to the non‐exercised group. Furthermore, maternal exercise produced lower reactive oxygen species (ROS) and oxidative stress in the foetal heart. In conclusion, maternal exercise mitigates ROS and oxidative damage in the foetal heart, and results in a lower incidence of CHDs in the offspring of pre‐gestational diabetes. Exercise may be an effective intervention to compliment clinical management and further minimize CHD risk in mothers with diabetes.

Sapropterin Treatment Prevents Congenital Heart Defects Induced by Pregestational Diabetes Mellitus in Mice

Background Tetrahydrobiopterin is a cofactor of endothelial NO synthase ( eNOS ), which is critical to embryonic heart development. We aimed to study the effects of sapropterin (Kuvan), an orally active synthetic form of tetrahydrobiopterin on eNOS uncoupling and congenital heart defects ( CHD s) induced by pregestational diabetes mellitus in mice. Methods and Results Adult female mice were induced to pregestational diabetes mellitus by streptozotocin and bred with normal male mice to produce offspring. Pregnant mice were treated with sapropterin or vehicle during gestation. CHD s were identified by histological analysis. Cell proliferation, eNOS dimerization, and reactive oxygen species production were assessed in the fetal heart. Pregestational diabetes mellitus results in a spectrum of CHD s in their offspring. Oral treatment with sapropterin in the diabetic dams significantly decreased the incidence of CHD s from 59% to 27%, and major abnormalities, such as atrioventricular septal defect and double-outlet right ventricle, were absent in the sapropterin-treated group. Lineage tracing reveals that pregestational diabetes mellitus results in decreased commitment of second heart field progenitors to the outflow tract, endocardial cushions, and ventricular myocardium of the fetal heart. Notably, decreased cell proliferation and cardiac transcription factor expression induced by maternal diabetes mellitus were normalized with sapropterin treatment. Furthermore, sapropterin administration in the diabetic dams increased eNOS dimerization and lowered reactive oxygen species levels in the fetal heart. Conclusions Sapropterin treatment in the diabetic mothers improves eNOS coupling, increases cell proliferation, and prevents the development of CHD s in the offspring. Thus, sapropterin may have therapeutic potential in preventing CHD s in pregestational diabetes mellitus.

A Systematic Review on the Protective Effect of N-Acetyl Cysteine Against Diabetes-Associated Cardiovascular Complications

INTRODUCTION

Heart failure is the leading cause of death in patients with diabetes. No treatment currently exists to specifically protect these patients at risk of developing cardiovascular complications. Accelerated oxidative stress-induced tissue damage due to persistent hyperglycemia is one of the major factors implicated in deteriorated cardiac function within a diabetic state. N-acetyl cysteine (NAC), through its enhanced capacity to endogenously synthesize glutathione, a potent antioxidant, has displayed abundant health-promoting properties and has a favorable safety profile.

OBJECTIVE

An increasing number of experimental studies have reported on the strong ameliorative properties of NAC. We systematically reviewed the data on the cardioprotective potential of this compound to provide an informative summary.

METHODS

Two independent reviewers systematically searched major databases, including PubMed, Cochrane Library, Google scholar, and Embase for available studies reporting on the ameliorative effects of NAC as a monotherapy or in combination with other therapies against diabetes-associated cardiovascular complications. We used the ARRIVE and JBI appraisal guidelines to assess the quality of individual studies included in the review. A meta-analysis could not be performed because the included studies were heterogeneous and data from randomized clinical trials were unavailable.

RESULTS

Most studies support the ameliorative potential of NAC against a number of diabetes-associated complications, including oxidative stress. We discuss future prospects, such as identification of additional molecular mechanisms implicated in diabetes-induced cardiac damage, and highlight limitations, such as insufficient studies reporting on the comparative effect of NAC with common glucose-lowering therapies. Information on the comparative analysis of NAC, in terms of dose selection, administration mode, and its effect on different cardiovascular-related markers is important for translation into clinical studies.

CONCLUSIONS

NAC exhibits strong potential for the protection of the diabetic heart at risk of myocardial infarction through inhibition of oxidative stress. The effect of NAC in preventing both ischemia and non-ischemic-associated cardiac damage is also of interest. Consistency in dose selection in most studies reported remains important in dose translation for clinical relevance.

Gestational diabetes mellitus modulates cholesterol homeostasis in human fetoplacental endothelium

Gestational diabetes mellitus (GDM) is associated with excessive oxidative stress which may affect placental vascular function. Cholesterol homeostasis is crucial for maintaining fetoplacental endothelial function. We aimed to investigate whether and how GDM affects cholesterol metabolism in human fetoplacental endothelial cells (HPEC). HPEC were isolated from fetal term placental arterial vessels of GDM or control subjects. Cellular reactive oxygen species (ROS) were detected by H₂DCFDA fluorescent dye. Oxysterols were quantified by gas chromatography-mass spectrometry analysis. Genes and proteins involved in cholesterol homeostasis were detected by real-time PCR and immunoblotting, respectively. Cholesterol efflux was determined from [³H]-cholesterol labeled HPEC and [¹⁴C]-acetate was used as cholesterol precursor to measure cholesterol biosynthesis and esterification. We detected enhanced formation of ROS and of specific, ROS-derived oxysterols in HPEC isolated from GDM versus control pregnancies. ROS-generated oxysterols were simultaneously elevated in cord blood of GDM neonates. Liver-X receptor activation in control HPEC by synthetic agonist TO901319, 7-ketocholesterol, or 7β-hydroxycholesterol upregulated ATP-binding cassette transporters (ABC)A1 and ABCG1 expression, accompanied by increased cellular cholesterol efflux. Upregulation of ABCA1 and ABCG1 and increased cholesterol release to apoA-I and HDL₃ (78 ± 17%, 40 ± 9%, respectively) were also observed in GDM versus control HPEC. The LXR antagonist GGPP reversed ABCA1 and ABCG1 upregulation and reduced the increased cholesterol efflux in GDM HPEC. Similar total cellular cholesterol levels were detected in control and GDM HPEC, while GDM enhanced cholesterol biosynthesis along with upregulated 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) and sterol O-acyltransferase 1 (SOAT1) mRNA and protein levels. Our results suggest that in GDM cellular cholesterol homeostasis in the fetoplacental endothelium is modulated via LXR activation and helps to maintain its proper functionality.

Palmitic acid, but not high-glucose, induced myocardial apoptosis is alleviated by N‑acetylcysteine due to attenuated mitochondrial-derived ROS accumulation-induced endoplasmic reticulum stress

Pharmacological inhibition of reactive oxygen species (ROS) is a potential strategy to prevent diabetes-induced cardiac dysfunction. This study was designed to investigate precise effects of antioxidant N‑acetylcysteine (NAC) in alleviating diabetic cardiomyopathy (DCM). Echocardiography and histologic studies were performed 12 weeks after streptozocin injection. Protein levels involved in endoplasmic reticulum stress (ERS) and apoptosis were analyzed by western blotting in diabetic hearts or high-glucose (HG, 30 mM)- and palmitic acid (PA, 300 μM)-cultured neonatal rat cardiomyocytes (NRCMs). ROS generation and structural alterations of mitochondria were also assessed. We report that NAC alleviated diabetes-induced cardiac abnormality, including restored ejection fraction (EF %), fraction shortening (FS %), peak E to peak A ratio (E/A) and reduced cardiac hypertrophy and fibrosis. These effects were concomitant with blocked ERS and apoptosis, as evidenced by inactivation of phosphorylated inositol-requiring enzyme-1α (IRE1α)/spliced X-box binding protein 1 (XBP1), phosphorylated protein kinase-like kinase (PERK)/phosphorylated eukaryotic initiation factor 2α (eIF2α) and glucose-regulated protein 78 (GRP78)/activating transcription factor 6 (ATF6α)/C/EBP homologous protein (CHOP) pathways, as well as suppressed Bcl-2-associated X protein (BAX)/B-cell lymphoma-2 (Bcl-2) and cleaved caspase 3 expressions. Mechanistically, PA mediated excessive mitochondrial ROS generation and oxidative stress, which were antagonized by NAC and Mito-TEMPO, a mitochondrial ROS inhibitor. No effects were noted by addition of apocynin, a nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor, and NADPH oxidase 4 (NOX 4) and NOX 2 expressions were not altered, indicating that PA-induced ROS generation is independent of NADPH oxidases. Most intriguingly, HG failed to promote ROS production despite its ability to promote ERS and apoptosis in NRCMs. Collectively, these findings indicate that NAC primarily abrogates PA-mediated mitochondrial ROS through ERS and therefore alleviates myocardial apoptosis but has little effect on HG-induced cardiac injury. This uncovers a potential role for NAC in formulating novel cardioprotective strategies in DCM patients.

Maternal diabetes up-regulates NOX2 and enhances myocardial ischaemia/reperfusion injury in adult offspring

Offspring of diabetic mothers are at risk of cardiovascular diseases in adulthood. However, the underlying molecular mechanisms are not clear. We hypothesize that prenatal exposure to maternal diabetes up‐regulates myocardial NOX2 expression and enhances ischaemia/reperfusion (I/R) injury in the adult offspring. Maternal diabetes was induced in C57BL/6 mice by streptozotocin. Glucose‐tolerant adult offspring of diabetic mothers and normal controls were subjected to myocardial I/R injury. Vascular endothelial growth factor (VEGF) expression, ROS generation, myocardial apoptosis and infarct size were assessed. The VEGF‐Akt (protein kinase B)‐mammalian target of rapamycin (mTOR)‐NOX2 signalling pathway was also studied in cultured cardiomyocytes in response to high glucose level. In the hearts of adult offspring from diabetic mothers, increases were observed in VEGF expression, NOX2 protein levels and both Akt and mTOR phosphorylation levels as compared to the offspring of control mothers. After I/R, ROS generation, myocardial apoptosis and infarct size were all significantly higher in the offspring of diabetic mothers relative to offspring of control mothers, and these differences were diminished by in vivo treatment with the NADPH oxidase inhibitor apocynin. In cultured cardiomyocytes, high glucose increased mTOR phosphorylation, which was inhibited by the PI3 kinase inhibitor LY294002. Notably, high glucose‐induced NOX2 protein expression and ROS production were inhibited by rapamycin. In conclusion, maternal diabetes promotes VEGF‐Akt‐mTOR‐NOX2 signalling and enhances myocardial I/R injury in the adult offspring. Increased ROS production from NOX2 is a possible molecular mechanism responsible for developmental origins of cardiovascular disease in offspring of diabetic mothers.

Maternal Diabetes, Birth Weight, and Neonatal Risk of Congenital Heart Defects in Norway, 1994-2009

OBJECTIVE

To investigate the association between pregestational or gestational diabetes and offspring risk of congenital heart defects and the association between large-for-gestational-age birth weight and risk of cardiac defects in offspring of diabetic women.

METHODS

Information on pregestational and gestational diabetes, cardiac defects, and birth weight among all births in Norway in 1994-2009 was ascertained from the Medical Birth Registry of Norway, national health registries, and the Cardiovascular Disease in Norway project. The relative risk (RR) compared offspring risk of cardiac defects for maternal diabetes with offspring risk in nondiabetic mothers adjusted for year of birth, maternal age, and parity.

RESULTS

Among 914,427 births (live births, stillbirths, terminated pregnancies), 5,618 (0.61%) were complicated by maternal pregestational diabetes and 9,726 (1.06%) by gestational diabetes. Congenital heart defects were identified in 10,575 offspring. The prevalence of cardiac defects differed between groups: 344 of 10,000 births to women with pregestational diabetes, 172 of 10,000 to women with gestational diabetes, and 114 of 10,000 in women without diabetes (adjusted RRs 2.92, 95% confidence interval [CI] 2.54-3.36 and 1.47, 95% CI 1.26-1.71). During the study period, the adjusted RRs for congenital heart defects did not change. The risk of cardiac defects in neonates very large for gestational age (birth weight greater than 3 standard deviations above the mean) was compared with neonates with birth weight appropriate for gestational age. For pregestational diabetes, the prevalences of offspring cardiac defects were 561 compared with 248 per 10,000 births (adjusted RR 2.23, 95% CI 1.39-3.59) and for gestational diabetes 388 compared with 132 per 10,000 (adjusted RR 2.73, 95% CI 1.53-4.85).

CONCLUSION

The increased risk of having a child with a congenital heart defect has not changed for diabetic women in Norway since 1994. Among women with pregestational or gestational diabetes, having a large-for-gestational-age neonate was associated with a two- to threefold increased risk of cardiac defects compared with neonates with normal birth weight.

The impaired myocardial ischemic tolerance in adult offspring of diabetic pregnancy is restored by maternal melatonin treatment

Diabetic pregnancy, with ever increasing prevalence, adversely affects embryogenesis and increases vasculometabolic disorder risks in adult offspring. However, it remains poorly understood whether maternal diabetes increases the offspring's susceptibility to heart injuries in adulthood. In this study, we observed that cardiac function and structure were comparable between adult offspring born to diabetic mice and their counterparts born to nondiabetic mice at baseline. However, in response to myocardial ischemia/reperfusion (MIR), diabetic mother offspring exhibited augmented infarct size, cardiac dysfunction, and myocardial apoptosis compared with control, in association with exaggerated activation of mitochondria- and endoplasmic reticulum (ER) stress-mediated apoptosis pathways and oxidative stress. Molecular analysis showed that the impaired myocardial ischemic tolerance in diabetic mother offspring was mainly attributable to blunted cardiac insulin receptor substrate (IRS)-1/Akt signaling. Furthermore, the effect of maternal melatonin administration on offspring's response to MIR was determined, and the results indicated that melatonin treatment in diabetic dams during pregnancy significantly improved the tolerance to MIR injury in their offspring, via restoring cardiac IRS-1/Akt signaling. Taken together, these data suggest that maternal diabetes predisposes offspring to augmented MIR injury in adulthood, and maternal melatonin supplementation during diabetic pregnancy may hold promise for improving myocardial ischemic tolerance in the offspring.

Stereological study of the effects of maternal diabetes on cerebellar cortex development in rat

Diabetes during pregnancy is associated with the deficits in balance and motor coordination and altered social behaviors in offspring. In the present study, we have investigated the effect of maternal diabetes and insulin treatment on the cerebellar volume and morphogenesis of the cerebellar cortex of rat neonates during the first two postnatal weeks. Sprague Dawley female rats were maintained diabetic from a week before pregnancy through parturition. At the end of pregnancy, the male offspring euthanized on postnatal days (P) 0, 7, and 14. Cavalieri's principle and fractionator methods were used to estimate the cerebellar volume, the thickness and the number of cells in the different layers of the cerebellar cortex. In spite of P0, there was a significant reduction in the cerebellar volume and the thickness of the external granule, molecular, and internal granule layers between the diabetic and the control animals. In diabetic group, the granular and purkinje cell densities were increased at P0. Moreover, the number of granular and purkinje cells in the cerebellum of diabetic neonates was reduced in comparison with the control group at P7 and P14. There were no significant differences in either the volume and thickness or the number of cells in the different layers of the cerebellar cortex between the insulin-treated diabetic group and controls. Our data indicate that diabetes in pregnancy disrupts the morphogenesis of cerebellar cortex. This dysmorphogenesis may be part of the cascade of events through which diabetes during pregnancy affects motor coordination and social behaviors in offspring.