Exposure of the developing heart to diabetic environment and early cardiac assessment: A review

The role of metabolism in cardiac development

Metabolism is the fundamental process that sustains life. The heart, in particular, is an organ of high energy demand, and its energy substrates have been studied for more than a century. In recent years, there has been a growing interest in understanding the role of metabolism in the early differentiation of pluripotent stem cells and in cancer research. Studies have revealed that metabolic intermediates from glycolysis and the tricarboxylic acid cycle act as co-factors for intracellular signal transduction, playing crucial roles in regulating cell behaviors. Mitochondria, as the central hub of metabolism, are also under intensive investigation regarding the regulation of their dynamics. The metabolic environment of the fetus is intricately linked to the maternal metabolic status, and the impact of the mother's nutrition and metabolic health on fetal development is significant. For instance, it is well known that maternal diabetes increases the risk of cardiac and nervous system malformations in the fetus. Another notable example is the decrease in the risk of neural tube defects when pregnant women are supplemented with folic acid. These examples highlight the profound influence of the maternal metabolic environment on the fetal organ development program. Therefore, gaining insights into the metabolic environment within developing fetal organs is critical for deepening our understanding of normal organ development. This review aims to summarize recent findings that build upon the historical recognition of the environmental and metabolic factors involved in the developing embryo.

Methyl Parathion Exposure Induces Development Toxicity and Cardiotoxicity in Zebrafish Embryos

Methyl parathion (MP) has been widely used as an organophosphorus pesticide for food preservation and pest management, resulting in its accumulation in the aquatic environment. However, the early developmental toxicity of MP to non-target species, especially aquatic vertebrates, has not been thoroughly investigated. In this study, zebrafish embryos were treated with 2.5, 5, or 10 mg/L of MP solution until 72 h post-fertilization (hpf). The results showed that MP exposure reduced spontaneous movement, hatching, and survival rates of zebrafish embryos and induced developmental abnormalities such as shortened body length, yolk edema, and spinal curvature. Notably, MP was found to induce cardiac abnormalities, including pericardial edema and decreased heart rate. Exposure to MP resulted in the accumulation of reactive oxygen species (ROS), decreased superoxide dismutase (SOD) activity, increased catalase (CAT) activity, elevated malondialdehyde (MDA) levels, and caused cardiac apoptosis in zebrafish embryos. Moreover, MP affected the transcription of cardiac development-related genes (vmhc, sox9b, nppa, tnnt2, bmp2b, bmp4) and apoptosis-related genes (p53, bax, bcl2). Astaxanthin could rescue MP-induced heart development defects by down-regulating oxidative stress. These findings suggest that MP induces cardiac developmental toxicity and provides additional evidence of MP toxicity to aquatic organisms.

Cardiac hypertrophy and insulin therapy in a pre-term newborn: is there a relationship?

Background

Hypertrophic cardiomyopathy (HCM) in newborns is a rare condition with heterogeneous etiologies. While the relationship between hyperinsulinism and cardiac hypertrophy (CH) is known, hyperinsulinism has not been reported as cause of HCM.

Case presentation

We report the case of cardiac hypertrophy (CH) in an Extremely Low Birth Weight (ELBW) infant; this patient underwent insulin therapy after the onset of persistent hyperglycemia due to parenteral nutrition (PN), supporting the hypothesis of a role of iatrogenic hyperinsulinemia in the development of HCM.

Conclusions

The present case underlines the importance of a close cardiological follow-up in infants undergoing insulin infusion for an alteration in the glucose metabolism.

Third Trimester Myocardial Performance Index in Fetuses from Women with Hyperglycemia in Pregnancy: A Systematic Review and Meta-Analysis

INTRODUCTION

 The myocardial performance index (MPI) has been proposed to evaluate cardiac dysfunction in newborns from diabetic mothers. Although MPI is routinely assessed in newborns, its role in the evaluation of fetuses from women with hyperglycemia in pregnancy (HIP) is still under evaluation. We aimed to evaluate the differences in third trimester fetal MPI in pregnant women with hyperglycemia compared to healthy controls.

MATERIALS AND METHODS

 Seven electronic databases were searched for all studies assessing women with HIP who underwent evaluation of fetal left MPI during pregnancy compared to a control group. The summary measures were reported as mean differences (MD) in the mean fetal left MPI between women with HIP and healthy controls, with a 95 % confidence interval (CI). A post hoc subgroup analysis based on the type of HIP - pregestational diabetes, GDM, or gestational impaired glucose tolerance (GIGT) - was performed as an additional analysis.

RESULTS

 14 studies assessing 1326 fetuses (580 from women with HIP and 746 from controls) were included. Women with HIP had a significantly higher mean left fetal MPI compared to controls (MD 0.08; 95 %CI: 0.05 to 0.11; p < 0.00 001). Subgroup analysis according to the type of HIP concurred with the overall analysis for women with DM (MD 0.07; 95 %CI: 0.01 to 0.13; p = 0.02) and for women with GDM (MD 0.012; 95 %CI: 0.07 to 0.17; p < 0.00 001) but not for women with GIGT (MD -0.01, 95 % CI -0.28 to 0.27; p = 0.96).

CONCLUSION

 Fetal left MPI is increased in pregnancies with HIP appearing as a potential marker of cardiac dysfunction.

Effect of maternal diabetes on fetal heart function on echocardiography: systematic review and meta-analysis

OBJECTIVE

Maternal diabetes in pregnancy is associated with structural anomalies of the fetal heart, as well as hypertrophy and functional impairment. This systematic review and meta-analysis aimed to estimate the effect of maternal diabetes on fetal cardiac function as measured by prenatal echocardiography.

METHODS

We performed a search of the EMBASE, PubMed and The Cochrane Library databases, from inception to 4 July 2019, for studies evaluating fetal cardiac function using echocardiography in pregnancies affected by diabetes compared with uncomplicated pregnancies. Outcome measures were cardiac hypertrophy and diastolic, systolic and overall cardiac function as assessed by various ultrasound parameters. The quality of the studies was assessed using the Newcastle-Ottawa Scale. Data on interventricular septal (IVS) thickness, myocardial performance index (MPI) and E/A ratio were pooled for the meta-analysis using random-effects models. For pregnancies with diabetes, results were reported overall and according to whether diabetes was pregestational (PDM) or gestational (GDM). Results were also stratified according to the trimester in which fetal cardiac assessment was performed.

RESULTS

Thirty-nine studies were included, comprising data for 2276 controls and 1925 women with pregnancy affected by diabetes mellitus (DM). Of these, 1120 had GDM, 671 had PDM and in 134 cases diabetes type was not specified. Fetal cardiac hypertrophy was more prevalent in diabetic pregnancies than in non-diabetic controls in 21/26 studies, and impaired diastolic function was observed in diabetic pregnancies in 22/28 studies. The association between DM and systolic function was inconsistent, with 10/25 studies reporting no difference between cases and controls, although more recent studies measuring cardiac deformation, i.e. strain, did show decreased systolic function in diabetic pregnancies. Of the studies measuring overall fetal cardiac function, the majority (14/21) found significant impairment in diabetic pregnancies. Results were similar when stratified according to GDM or PDM. These effects were already present in the first trimester, but were most profound in the third trimester. Meta-analysis of studies performed in the third trimester showed, compared with controls, increased IVS thickness in both PDM (mean difference, 0.75 mm (95% CI, 0.56-0.94 mm)) and GDM (mean difference, 0.65 mm (95% CI, 0.39-0.91 mm)) pregnancies, decreased E/A ratio in PDM pregnancies (mean difference, -0.09 (95% CI, -0.15 to -0.03)), no difference in E/A ratio in GDM pregnancies (mean difference, -0.01 (95% CI, -0.02 to 0.01)) and no difference in MPI in either PDM (mean difference, 0.04 (95% CI, -0.01 to 0.09)) or GDM (mean difference, 0.03 (95% CI, -0.01 to 0.06)) pregnancies.

CONCLUSIONS

The findings of this review show that maternal diabetes is associated with fetal cardiac hypertrophy, diastolic dysfunction and overall impaired myocardial performance on prenatal ultrasound, irrespective of whether diabetes is pregestational or gestational. Further studies are needed to demonstrate the relationship with long-term outcomes. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Development toxicity and cardiotoxicity in zebrafish from exposure to iprodione

Iprodione is a highly effective broad-spectrum fungicide commonly used for early disease control in fruit trees and vegetables. Pesticides often flow into watercourses due to rainfall, causing toxicity in non-target organisms, eventually entering the food chain. However, little information is available in the current literature about the toxicity of iprodione to cardiac development. The present study aimed to investigate the effect of iprodione on early embryonic development and its cardiotoxicity in aquatic animals, using zebrafish as a model. At 6-72 h post-fertilization (hpf), zebrafish were exposed to concentrations of 15 mg/L, 20 mg/L, and 25 mg/L (72 h-LC₅₀ = 21.15 mg/L). We found that exposure to iprodione resulted in yolk edema, increased mortality, and shortened body length in zebrafish embryos. In addition, iprodione was also found to induce edema in the pericardium of zebrafish, decrease heart rate, and cause the failure of cardiac cyclization. Exposure to iprodione significantly increased the accumulation of ROS and altered the activity of antioxidant enzymes (MDA, CAT) in zebrafish embryos. Moreover, iprodione induced changes in the transcription levels of heart developmental-related genes and apoptosis-related genes. In addition, Astaxanthin (antioxidant) can partially rescue the toxic phenotype caused by iprodione. Apoptosis-related genes and heart developmental-related genes were rescued after astaxanazin treatment. The results suggest that iprodione induces developmental and cardiac toxicity in zebrafish embryos, which provides new evidence of the toxicity of iprodione to organisms in aquatic ecosystems and assessing human health risks.

Longitudinal assessment of ventricular strain, tricuspid and mitral annular plane systolic excursion (TAPSE and MAPSE) in fetuses from pregnancies complicated by diabetes mellitus

OBJECTIVES

To evaluate fetal cardiac function using myocardial deformation analyses, tricuspid annular plane systolic excursion (TAPSE), mitral annular plane systolic excursion (MAPSE) and diastolic function parameters in pregnancies complicated by maternal diabetes mellitus.

METHODS

Myocardial deformation using velocity vector imaging (VVI), TAPSE, MAPSE and diastolic function was measured in 126 women with uncomplicated singleton pregnancies and 50 women with diabetes mellitus. Women underwent ultrasound scans every four weeks from recruitment (18-28 weeks gestational age) until delivery.

RESULTS

Left ventricle strain and strain rate, right ventricle strain and strain rate, TAPSE, MAPSE and diastolic parameters were not different between the diabetic cohort and controls throughout gestation. We did not find any significant correlation between the fetal cardiac function parameters with parity or smoking status. There was however a significant difference in strain and strain rate values in the left ventricle, but not the right ventricle in women with BMI >30 kg/m², and reduced TAPSE values in this same group. Fetuses in the diabetes group had thicker interventricular septum (IVS) throughout gestation.

CONCLUSION

Myocardial deformation of the fetal left ventricle, as measured by VVI, and TAPSE were reduced in fetuses of mothers in association with maternal obesity but not in women with diabetes mellitus. No significant differences in the fetal cardiac function parameters measured were different between the two groups, except for IVS thickness.

Associations of Maternal Glycemia in the First Half of Pregnancy With Alterations in Cardiac Structure and Function in Childhood

OBJECTIVE

Gestational diabetes mellitus has been associated with offspring cardiac congenital malformations, ventricular hypertrophy, and diastolic dysfunction in large observational cohort studies and experimental animal models. We assessed the associations of maternal random glucose concentrations across the full range with childhood cardiac ventricular structure and function.

RESEARCH DESIGN AND METHODS

In a population-based prospective cohort among 1,959 women and their offspring, maternal random glucose concentrations were measured at a median 13.1 weeks' gestation (95% range 10.5-16.8 weeks). We obtained offspring cardiac outcomes, relative to body size, through cardiac MRI at 10 years.

RESULTS

The mean maternal random glucose concentration was 4.4 mmol/L (SD 0.8). The highest quintile of maternal glucose concentrations, compared with the lowest quintile, was associated with a lower childhood left ventricular mass (-0.19 SD score [SDS]; 95% CI -0.31, -0.07) and left ventricular end-diastolic volume (-0.17 SDS; 95% -0.28, -0.05). Also, higher maternal glucose concentrations across the full range per 1 mmol/L increase were associated with a lower childhood left ventricular mass and left ventricular end-diastolic volume (P values ≤0.05). Adjustment for maternal prepregnancy BMI, gestational age, and weight at birth or childhood BMI and blood pressure did not influence the effect estimates. Maternal glucose concentrations were not significantly associated with childhood right ventricular end-diastolic volume or left and right ventricular ejection fraction.

CONCLUSIONS

Higher maternal random glucose concentrations in the first half of pregnancy are associated with a lower childhood left ventricular mass and left ventricular end-diastolic volume, with the strongest associations for childhood left ventricular mass. These associations were not explained by maternal, birth, or childhood characteristics. Further studies are needed to replicate these findings using repeated maternal glucose measurements throughout pregnancy and offspring cardiac outcomes throughout childhood and adulthood.

Could the E/A ratio be included in the cardiological evaluation of the offspring of diabetic mothers? A case-control study in South Sardinia

INTRODUCTION

Diabetes mellitus (DM) is a chronic disease widespread in the world. Sardinia represents, together with Finland, the region with the highest incidence of type 1 DM (DM1), as well as a high prevalence of gestational DM (GDM). Despite the improvement in obstetric surveillance, perinatal and long-term adverse outcomes are still frequent in the offspring of diabetic mothers. During gestations complicated by DM, fetal heart is one of the most affected organ potentially undergoing structural heart defects or several degrees of fetal myocardium hypertrophy and impaired cardiac function.

AIM

The aim of our study was to evaluate, through echocardiographic examination, cardiac features and performance in a South Sardinian population of newborns of diabetic mothers comparing them to a group of control subjects.

CONCLUSIONS

In our sample, the E/A ratio resulted a significant marker of early diastolic dysfunction in asymptomatic neonates born by diabetic mothers, even if such result should be confirmed on larger samples.

Metabolic environment in vivo as a blueprint for differentiation and maturation of human stem cell-derived cardiomyocytes

Patient-derived human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) are increasingly being used for disease modeling, drug screening and regenerative medicine. However, to date, an immature, fetal-like, phenotype of hPSC-CMs restrains their full potential. Increasing evidence suggests that the metabolic state, particularly important for provision of sufficient energy in highly active contractile CMs and anabolic and regulatory processes, plays an important role in CM maturation, which affects crucial functional aspects of CMs, such as contractility and electrophysiology. During embryonic development the heart is subjected to metabolite concentrations that differ substantially from that of hPSC-derived cardiac cell cultures. A deeper understanding of the environmental and metabolic cues during embryonic heart development and how these change postnatally, will provide a framework for optimizing cell culture conditions and maturation of hPSC-CMs. Maturation of hPSC-CMs will improve the predictability of disease modeling, drug screening and drug safety assessment and broadens their applicability for personalized and regenerative medicine.

AHR-mediated oxidative stress contributes to the cardiac developmental toxicity of trichloroethylene in zebrafish embryos

Trichloroethylene (TCE), a widely used chlorinated solvent, is a common environmental pollutant. Current evidence shows that TCE could induce heart defects during embryonic development, but the underlining mechanism(s) remain unclear. Since activation of the aryl hydrocarbon receptor (AHR) could induce oxidative stress, we hypothesized that AHR-mediated oxidative stress may play a role in the cardiac developmental toxicity of TCE. In this study, we found that the reactive oxygen species (ROS) scavenger, N-Acetyl-L-cysteine (NAC), and AHR inhibitors, CH223191 (CH) and StemRegenin 1, significantly counteracted the TCE-induced heart malformations in zebrafish embryos. Moreover, both CH and NAC suppressed TCE-induced ROS and 8-OHdG (8-hydroxy-2' -deoxyguanosine). TCE did not affect ahr2 and cyp1a expression, but increased cyp1b1 expression, which was restored by CH supplementation. CH also attenuated the TCE-induced mRNA expression changes of Nrf2 signalling genes (nrf2b, gstp2, sod2, ho1, nqo1) and cardiac differentiation genes (gata4, hand2, c-fos, sox9b). In addition, the TCE enhanced SOD activity was attenuated by CH. Morpholino knockdown confirmed that AHR mediated the TCE-induced ROS and 8-OHdG generation in the heart of zebrafish embryos. In conclusion, our results suggest that AHR mediates TCE-induced oxidative stress, leading to DNA damage and heart malformations in zebrafish embryos.

Applicability of Standardized Early Fetal Heart Examination in the Obese Population

OBJECTIVE

This study aimed to evaluate the impact of obesity on early evaluation of fetal cardiac landmarks using a standardized examination method at the time of nuchal translucency scan.

METHODS

This was a cross-sectional study of an ongoing prospective cohort at high risk for congenital heart defects. We used a standardized examination protocol using 2-dimensional sonography with power Doppler in the evaluation of fetal cardiac landmarks consisting of 4-chamber view, outflow tract relationship, and transverse arches view. The study population was stratified based on maternal body mass index into nonobese (<30 kg/m² ) and obese (≥30 kg/m² ). Groups were compared in terms of satisfactory evaluation of fetal cardiac landmarks, transvaginal sonography use, and scan times required for the evaluations. Subanalysis was performed by further categorizing obesity into nonmorbid obesity (30.0-39.9 kg/m² ) and morbid obesity (≥40 kg/m² ).

RESULTS

A total of 190 patients were evaluated. Of these, 48.4% (n = 92) were obese. The most common indication for fetal cardiac assessment was maternal pregestational diabetes mellitus (42.6%). Transvaginal sonography was utilized in one nonobese woman (1.4%) and 11 obese women (12%) (P = .002). The satisfactory evaluation of 4-chamber view, outflow tract relationship, transverse arches view, and all views were not significantly different between groups (P > .05). The scan time was about 5 minutes longer in the obese group compared with nonobese group (P = .020).

CONCLUSIONS

Obesity does not hamper early evaluation of fetal cardiac landmarks around the time of nuchal translucency scan. However, obese patients are more likely to require transvaginal examinations.