Fetal origins of adult cardiac disease: a novel approach to prevent fetal growth restriction induced cardiac dysfunction using insulin like growth factor

BACKGROUND

Fetal growth restriction (FGR) is a risk factor for adult cardiovascular disease. Intraplacental gene transfer of human insulin-like growth factor-1 (IGF-1) corrects birth weight in our mouse model of FGR. This study addresses long term effects of FGR on cardiac function and the potential preventive effect of IGF-1.

STUDY DESIGN

Laparotomy was performed on pregnant C57BL/6J mice at embryonic day 18 and pups were divided into three groups: Sham operated; FGR (induced by mesenteric uterine artery ligation); treatment (intraplacental injection of IGF-1 after uterine artery ligation). Pups were followed until 32 wk of life. Transthoracic echocardiography was performed starting at 12 wk.

RESULTS

Systolic cardiac function was significantly impaired in the FGR group with reduced fractional shortening compared with sham and treatment group starting at week 12 of life (20 ± 4 vs. 31 ± 5 vs. 32 ± 5, respectively, n = 12 for each group; P < 0.001) with no difference between the sham and treatment groups.

CONCLUSION

Intraplacental gene transfer of IGF-1 prevents FGR induced cardiac dysfunction. This suggests that in utero therapy may positively impact cardiac remodeling and prevent adult cardiovascular disease.

Online versus offline spatiotemporal image correlation (STIC) M-mode for the evaluation of cardiac longitudinal annular displacement in fetal growth restriction

PURPOSE

Our first aim was to compare online M-mode with offline spatiotemporal image correlation (STIC) M-mode for assessing longitudinal annular displacement (LAD) in growth-restricted fetuses (FGR). Our second aim was to compare LAD measures of FGR cases with controls.

MATERIALS AND METHODS

Prospective study including 40 FGR cases (defined estimated fetal weight and birth weight <10th centile) and 72 normally grown fetuses matched to cases by gestational age at scan. LAD was measured with online M-mode and offline STIC M-mode at the left and right ventricular free walls and septum in all fetuses.

RESULTS

FGR cases had a significant decrease in LAD by STIC in all sites as compared to controls (e.g. right LAD in FGR mean 6.7 mm (SD 1.2) versus controls 7.2 mm (1.2), p = .033). There was a non-significant trend for lower values in FGR when using online M-mode (e.g. right LAD in FGR 6.9 mm (1.5) versus controls 7.4 mm (1.5), p = .084).

CONCLUSIONS

STIC M-mode seems a better method than online M-mode for detecting subtle changes in myocardial motion. STIC presents more precise results and allows an ideal placement of the M-mode arrow. These results confirm previous data suggesting decreased longitudinal motion in FGR.

The effect of foetal growth restriction on the development of migraine and tension-type headache in adulthood. The HUNT Study

BACKGROUND

There is little knowledge about how factors early in life affect the development of migraine and tension-type headache. We aimed to examine whether growth restriction in utero is associated with development of migraine and frequent tension-type headache in adults.

METHODS

The population-based Nord-Trøndelag Health Study (HUNT 3) contained a validated headache questionnaire, which differentiated between migraine and tension-type headache. These data were linked to information on weight and gestational age at birth from the Norwegian Medical Birth Registry. In total 4557 females and 2789 males, aged 19-41 years, were included in this registry-based study. Participants were categorized as appropriate for gestational age (AGA, 10th-90th percentile), small for gestational age (SGA, 3rd-10th percentile) or very small for gestational age (VSGA, < 3rd percentile). Logistic regression was used to calculate odds ratios (OR) with 95% confidence intervals (CI) for migraine and tension-type headache, with exposure being growth restriction at birth.

RESULTS

The effect of growth restriction on migraine was modified by sex, with a significant association in males (p<0.001), but not in females (p = 0.20). In particular, males born VSGA were at increased risk of developing migraine (OR 2.73, 95% CI 1.63-4.58, p<0.001), with an intermediate risk among those born SGA (OR 1.50, 95% CI 0.96-2.35, p = 0.08) compared to those born AGA. There was no significant association between growth restriction and frequent TTH (p = 0.051).

CONCLUSION

Growth restriction was associated with increased risk of migraine in adulthood among males, but not among females. This suggests that migraine might, in part, be influenced by early life events, and that males seem to be particularly vulnerable.

Prediction of delivery of small-for-gestational-age neonates and adverse perinatal outcome by fetoplacental Doppler at 37 weeks' gestation

OBJECTIVE

To explore the predictive capacity of fetoplacental Doppler at 37 weeks' gestation in identifying small-for-gestational-age (SGA) neonates, fetal growth restriction (FGR) and adverse perinatal outcome.

METHODS

This was a prospective cohort study of low-risk singleton pregnancies undergoing ultrasound assessment at 37 weeks. At study inclusion, biometry for estimated fetal weight (EFW), and fetoplacental Doppler variables (uterine artery pulsatility index (UtA-PI), cerebroplacental ratio (CPR) and umbilical vein blood flow (UVBF) normalized by EFW) were measured. SGA was defined as a customized birth weight between the 3^rd and 10^th centiles, and FGR was defined as a birth weight < 3^rd centile, according to local standards. Adverse perinatal outcomes included emergency Cesarean section for non-reassuring fetal status, 5-min Apgar score < 7 and neonatal acidosis at birth.

RESULTS

A total of 946 pregnancies were included in the study. Of these, 89 (9.4%) were classified as SGA and 40 (4.2%) as FGR, with an overall rate of adverse perinatal outcome of 4.9%. At a fixed 10% false-positive rate (FPR), the detection rate of SGA by EFW, UtA-PI, CPR, UVBF and by a combination of Doppler variables (UtA-PI and CPR) and EFW was 59.2%, 10.5%, 13.7%, 3.2% and 61.0%, respectively. At a fixed 10% FPR, the detection rate of FGR by EFW, UtA-PI, CPR, UVBF and a combination of CPR and EFW centile was 83.3%, 13.9%, 27.8%, 13.9% and 88.6%, respectively. At a fixed 10% FPR, the detection rate of adverse perinatal outcome by EFW, UtA-PI, CPR and UVBF was 19.2%, 9.2%, 23.1% and 16.9%, respectively, while combining EFW with Doppler variables (including CPR and UVBF normalized by EFW) improved the detection rate to nearly 30%.

CONCLUSION

In low-risk pregnancies, Doppler evaluation at 37 weeks' gestation did not improve the prediction of SGA and FGR compared with that given by EFW alone, however, combining Doppler variables with EFW improved the prediction of adverse perinatal outcomes given by these parameters alone, although not markedly. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Pregnancy as a critical window for blood pressure regulation in mother and child: programming and reprogramming

Pregnancy is a critical time for long-term blood pressure regulation in both mother and child. Pregnancies complicated by placental insufficiency, resulting in pre-eclampsia and intrauterine growth restriction, are associated with a threefold increased risk of the mother to develop hypertension later in life. In addition, these complications create an adverse intrauterine environment, which programmes the foetus and the second generation to develop hypertension in adult life. Female offspring born to a pregnancy complicated by placental insufficiency are at risk for pregnancy complications during their own pregnancies as well, resulting in a vicious circle with programmed risk for hypertension passing from generation to generation. Here, we review the epidemiology and mechanisms leading to the altered programming of blood pressure trajectories after pregnancies complicated by placental insufficiency. Although the underlying mechanisms leading to hypertension remain the subject of investigation, several abnormalities in angiotensin sensitivity, sodium handling, sympathetic activity, endothelial function and metabolic pathways are found in the mother after exposure to placental insufficiency. In the child, epigenetic modifications and disrupted organ development play a crucial role in programming of hypertension. We emphasize that pregnancy can be viewed as a window of opportunity to improve long-term cardiovascular health of both mother and child, and outline potential gains expected of improved preconceptional, perinatal and post-natal care to reduce the development of hypertension and the burden of cardiovascular disease later in life. Perinatal therapies aimed at reprogramming hypertension are a promising strategy to break the vicious circle of intergenerational programming of hypertension.

Ehmt2/G9a controls placental vascular maturation by activating the Notch pathway

Defective fetoplacental vascular maturation causes intrauterine growth restriction (IUGR). A transcriptional switch initiates placental maturation where blood vessels elongate. However, cellular mechanisms and regulatory pathways involved are unknown. We show that the histone methyltransferase Ehmt2, also known as G9a, activates the Notch pathway to promote placental vascular maturation. Placental vasculature from embryos with G9a-deficient endothelial progenitor cells failed to expand due to decreased endothelial cell proliferation and increased trophoblast proliferation. Moreover, G9a deficiency altered the transcriptional switch initiating placental maturation and caused downregulation of Notch pathway effectors including Rbpj. Importantly, Notch pathway activation in G9a-deficient endothelial progenitors extended embryonic life and rescued placental vascular expansion. Thus, G9a activates the Notch pathway to balance endothelial cell and trophoblast proliferation and coordinates the transcriptional switch controlling placental vascular maturation. Accordingly, G9A and RBPJ were downregulated in human placentae from IUGR-affected pregnancies, suggesting that G9a is an important regulator in placental diseases caused by defective vascular maturation.

Early nutrition, epigenetics, and cardiovascular disease

PURPOSE OF REVIEW

Here, we provide a summary of the current knowledge on the impact of early life nutrition on cardiovascular diseases that have emerged from studies in humans and experimental animal models. The involvement of epigenetic mechanisms in the Developmental Origins of Health and Disease will be discussed in relation to the implications for the heart and the cardiovascular system.

RECENT FINDINGS

Environmental cues, such as parental diet and a suboptimal in utero environment can shape growth and development, causing long-lasting cardiometabolic perturbations. Increasing evidence suggest that these effects are mediated at the epigenomic level, and can be passed onto future generations. In the last decade, epigenetic mechanisms (DNA methylation, histone modifications) and RNA-based mechanisms (microRNAs, piRNAs, and tRNAs) have therefore emerged as potential candidates for mediating inheritance of cardiometabolic diseases.

SUMMARY

The burden of obesity and associated cardiometabolic diseases is believed to arise through interaction between an individual's genetics and the environment. Moreover, the risk of developing poor cardiometabolic health in adulthood is defined by early life exposure to pathological cues and can be inherited by future generations, initiating a vicious cycle of transmission of disease. Elucidating the molecular triggers of such a process will help tackle and prevent the uncontrolled rise in obesity and cardiometabolic disease.

Altered cardiovascular function at birth in growth-restricted preterm lambs

BACKGROUND

Cardiovascular dysfunction at birth may underlie poor outcomes after fetal growth restriction (FGR) in neonates. We compared the cardiovascular transition between FGR and appropriately grown (AG) preterm lambs and examined possible mechanisms underlying any cardiovascular dysfunction in FGR lambs.

METHODS

FGR was induced in ewes bearing twins at 0.7 gestation; the twin was used as an internal control (AG). At 0.8 gestation, lambs were delivered and either euthanized with their arteries isolated for in vitro wire myography, or ventilated for 2 h. At 60 min, inhaled nitric oxide (iNO) was administered in a subgroup for 30 min. Molecular assessment of the nitric oxide (NO) pathway within lung tissue was conducted.

RESULTS

FGR lambs had lower left ventricular output and cerebral blood flow (CBF) and higher systemic vascular resistance compared with AG lambs. INO administration to FGR lambs rapidly improved cardiovascular and systemic hemodynamics but resulted in decreased CBF in AG lambs. Isolated arteries from FGR lambs showed impaired sensitivity to NO donors, but enhanced vasodilation to Sildenafil and Sodium nitroprusside, and altered expression of components of the NO pathway.

CONCLUSION

Cardiovascular dysfunction at birth may underlie the increased morbidity and mortality observed in preterm FGR newborns. Impaired NO signaling likely underlies the abnormal vascular reactivity.

Fetal cardiovascular remodeling persists at 6 months in infants with intrauterine growth restriction

OBJECTIVES

Intrauterine growth restriction is associated with increased cardiovascular risk later in life but the link between fetal disease and postnatal risk is not well-documented. We evaluated longitudinally the association between cardiovascular remodeling in small-for-gestational-age (SGA) fetuses and at 6 months of age.

METHODS

A cohort of 80 SGA fetuses (defined by estimated fetal and birth weights < 10(th) centile) delivered > 34 weeks' gestation was compared with 80 normally grown age-matched control fetuses, with follow-up at 6 months of corrected age (i.e. 6 months from estimated date of delivery according to first-trimester crown-rump length). Cardiovascular evaluation included a comprehensive echocardiographic assessment in both fetuses and infants and blood pressure and aortic intima-media thickness (aIMT) measurement in infants. Parameters were adjusted by linear regression analysis for gender, gestational age at delivery, pre-eclampsia, prenatal glucocorticoid exposure, Cesarean delivery, admission to neonatal intensive care unit and body surface area.

RESULTS

Both pre- and postnatally, when compared with controls, the SGA group showed a more globular cardiac shape (left sphericity index: controls 2.06 vs SGA 1.87 (P = 0.022) prenatally and 1.92 vs 1.67 (P = 0.007) postnatally), as well as signs of systolic longitudinal dysfunction (systolic annular peak velocity (S'): 7.2 vs 6.3 cm/s (P = 0.003) prenatally and 7.9 vs 6.4 cm/s (P < 0.001) postnatally; tricuspid annular plane systolic excursion: 7.2 vs 6.8 mm (P = 0.015) prenatally and 16.0 vs 14.2 mm (P < 0.001) postnatally) and diastolic dysfunction (left isovolumetric relaxation time: 46 vs 52 ms (P < 0.001) prenatally and 50 vs 57 ms (P = 0.034) postnatally). In addition, infants in the SGA group had increased mean blood pressure (mean: 61 vs 70 mmHg, P < 0.001) and maximum aIMT (0.57 vs 0.66 mm; P < 0.001).

CONCLUSIONS

Primary cardiovascular changes are already present in the SGA fetus and persist at 6 months of age. These data support prenatal cardiovascular remodeling as a mechanistic pathway of increased risk later in life in cases of SGA, regardless of Doppler abnormalities. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Intrauterine growth restriction inhibits expression of eukaryotic elongation factor 2 kinase, a regulator of protein translation

Nutrient deprivation suppresses protein synthesis by blocking peptide elongation. Transcriptional upregulation and activation of eukaryotic elongation factor 2 kinase (eEF2K) blocks peptide elongation by phosphorylating eukaryotic elongation factor 2. Previous studies examining placentas from intrauterine growth restricted (IUGR) newborn infants show decreased eEF2K expression and activity despite chronic nutrient deprivation. However, the effect of IUGR on hepatic eEF2K expression in the fetus is unknown. We, therefore, examined the transcriptional regulation of hepatic eEF2K gene expression in a Sprague-Dawley rat model of IUGR. We found decreased hepatic eEF2K mRNA and protein levels in IUGR offspring at birth compared with control, consistent with previous placental observations. Furthermore, the CpG island within the eEF2K promoter demonstrated increased methylation at a critical USF 1/2 transcription factor binding site. In vitro methylation of this binding site caused near complete loss of eEF2K promoter activity, designating this promoter as methylation sensitive. The eEF2K promotor in IUGR offspring also lost the protective histone covalent modifications associated with unmethylated CGIs. In addition, the +1 nucleosome was displaced 3' and RNA polymerase loading was reduced at the IUGR eEF2K promoter. Our findings provide evidence to explain why IUGR-induced chronic nutrient deprivation does not result in the upregulation of eEF2K gene transcription.

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.

Intrauterine growth restriction combined with a maternal high-fat diet increases hepatic cholesterol and low-density lipoprotein receptor activity in rats

Intrauterine growth restriction (IUGR) and maternal consumption of a high-saturated-fat diet (HFD) increase the risk of hypercholesterolemia, a leading cause of morbidity and mortality. Many pregnant women eat a HFD, thus exposing the fetus to a HFD in utero. The cumulative effect of in utero exposure to IUGR and a HFD on offspring cholesterol levels remains unknown. Furthermore, little is known about the mechanism through which IUGR and maternal HFD consumption increase cholesterol. We hypothesize that IUGR combined with a maternal HFD would increase offspring serum and hepatic cholesterol accumulation via alteration in levels of key proteins involved in cholesterol metabolism. To test our hypothesis we used a rat model of surgically induced IUGR and fed the dams a regular diet or a HFD HFD-fed dams consumed the same kilocalories as regular diet-fed dams, with no difference between surgical intervention groups. In the offspring, IUGR combined with a maternal HFD increased hepatic cholesterol levels, low-density lipoprotein (LDL) receptor protein levels, and Ldlr activity in female rat offspring at birth and both sexes at postnatal day 14 relative to non-IUGR offspring both from regular diet- and HFD-fed dams. These findings suggest that IUGR combined with a maternal HFD increases hepatic cholesterol accumulation via increased LDL cholesterol uptake into the liver with resulting persistent increases in hepatic cholesterol accumulation.

Zidovudine treatment in HIV-infected pregnant women is associated with fetal cardiac remodelling

OBJECTIVE

To evaluate the cardiac structure and function of the fetuses of pregnant women with HIV infection on combined antiretroviral treatment (cART) and the HIV-related and nonrelated determinants of abnormal findings.

DESIGN

A prospective cohort study including 42-noninfected fetuses from HIV pregnant women on cART and 84 fetuses from non-HIV-infected women.

METHODS

Fetal echocardiography was performed at 26-32 weeks of pregnancy to assess cardiac structure and function. The impact of maternal and perinatal factors on fetal cardiac remodelling was evaluated by multivariate regression analysis.

RESULTS

Fetuses from HIV pregnant women on cART presented larger hearts and pericardial effusion together with thicker myocardial septal walls (mean 3.56 mm (SD 0.88) vs non-HIV mean 2.75 mm (SD 0.77); P = 0.002) and smaller left ventricular cavities (10.81 mm (SD 2.28) vs 12.3 mm (SD 2.54); P = 0.033). Fetuses from HIV women also presented signs of systolic (mitral systolic annular peak velocity 5.85 cm/s (SD 0.77) vs non-HIV 6.25 cm/s (SD 0.97); P = 0.007) and diastolic (isovolumic relaxation time 52 ms (SD 8.91) vs non-HIV 45 ms (SD 7.98); P < 0.001) dysfunction. In the multivariate analysis, maternal treatment with zidovudine was the only factor significantly associated with fetal cardiac changes (P = 0.014).

CONCLUSION

Fetuses from HIV-infected mothers on cART have cardiac remodelling and dysfunction, which might explain the cardiovascular changes described in childhood. Fetal cardiac remodelling was essentially associated with maternal treatment with zidovudine which challenges its use during pregnancy.

Growth Asymmetry, Head Circumference, and Neurodevelopmental Outcomes in Infants with Single Ventricles

OBJECTIVE

To assess the variability in asymmetric growth and its association with neurodevelopment in infants with single ventricle (SV).

STUDY DESIGN

We analyzed weight-for-age z-score minus head circumference-for-age z-score (HCAZ), relative head growth (cm/kg), along with individual growth variables in subjects prospectively enrolled in the Infant Single Ventricle Trial. Associations between growth indices and scores on the Psychomotor Developmental Index (PDI) and Mental Developmental Index (MDI) of the Bayley Scales of Infant Development-II (BSID-II) at 14 months were assessed.

RESULTS

Of the 230 subjects enrolled in the Infant Single Ventricle trial, complete growth data and BSID-II scores were available in 168 (73%). Across the cohort, indices of asymmetric growth varied widely at enrollment and before superior cavopulmonary connection (SCPC) surgery. BSID-II scores were not associated with these asymmetry indices. In bivariate analyses, greater pre-SCPC HCAZ correlated with higher MDI (r = 0.21; P = .006) and PDI (r = 0.38; P < .001) and a greater HCAZ increase from enrollment to pre-SCPC with higher PDI (r = 0.15; P = .049). In multivariable modeling, pre-SCPC HCAZ was an independent predictor of PDI (P = .03), but not MDI.

CONCLUSION

In infants with SV, growth asymmetry was not associated with neurodevelopment at 14 months, but pre-SCPC HCAZ was associated with PDI. Asymmetric growth, important in other high-risk infants, is not a brain-sparing adaptation in infants with SV.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT00113087.

Influence of breastfeeding and postnatal nutrition on cardiovascular remodeling induced by fetal growth restriction

BACKGROUND

Our aim was to determine the influence of breastfeeding and postnatal nutrition on cardiovascular remodeling induced by fetal growth restriction (FGR).

METHODS

A cohort study including 81 children with birthweight <10th centile (FGR) and 121 with adequate fetal growth for gestational age (AGA) was conducted. Cardiovascular endpoints were left ventricular sphericity index (LVSI), carotid intima-media thickness (cIMT), and blood pressure (BP) at 4-5 y of age. The combined effect of FGR and postnatal variables-including breastfeeding, fat dietary intake, and BMI-on cardiovascular endpoints was assessed by linear and robust regressions.

RESULTS

FGR was the strongest predictor of cardiovascular remodeling in childhood, leading to lower LVSI and increased cIMT and BP as compared with AGA. Breastfeeding >6 mo (coefficient: 0.0982) and healthy-fat dietary intake (coefficient: -0.0128) showed an independent beneficial effect on LVSI and cIMT, respectively. Overweight/obesity induced an additional increment of 1 SD on cIMT in FGR children (interaction coefficient: 0.0307) when compared with its effect in AGA. BMI increased systolic BP (coefficient: 0.7830) while weight catch-up increased diastolic BP (coefficient: 4.8929).

CONCLUSIONS

Postnatal nutrition ameliorates cardiovascular remodeling induced by FGR. Breastfeeding and healthy-fat dietary intake improved while increased BMI worsened cardiovascular endpoints, which opens opportunities for targeted postnatal interventions from early life.

Donor catch-up growth after laser surgery for twin-twin transfusion syndrome

OBJECTIVE

To assess fetal growth after laser surgery for TTTS at the time of prenatal diagnosis, birth, and at 2years of age.

DESIGN/METHODS

Growth data were collected from surviving children treated between 2007 and 2010 as part of a study to assess neurodevelopment at 24months (±6weeks) corrected age. Fetal weights were obtained via ultrasound using Hadlock's formula at the time of preoperative assessment for laser surgery. Birth weights were recorded by the staff at the delivering institutions. Weights at 2years corrected age were recorded at the time of neurodevelopmental testing. Weights were converted into percentiles according to standard growth curves. Growth restriction was defined as <10th percentile for given age. Multilevel latent growth curve models in Mplus (twins nested in families) examined weight change over time as a function of donor status, and repeated measures ANOVA was utilized to assess in donor-recipient weight discordance over time for twin pairs.

RESULTS

99 of 206 children (56 of 130 families) were studied. There were no differences between enrolled and non-enrolled patients in donor/recipient status and survival rates, fetal demise, intrauterine growth restriction, Quintero stage, and gestational age of surgery or delivery. 48.5% were donors. The median fetal, birth, and 2-year weights for all twins were 288g, 1.9kg, and 11.8kg, respectively, and the overall prevalence of growth restriction was 28%, 22%, and 3%, respectively. Growth restriction rates at prenatal diagnosis were 56% in donors vs. 2% in recipients (OR=64.3, p<0.001); at birth, 35% vs. 10% (OR=5.0, p<0.01); and at 2years, 6% vs. 0%. Donors showed significant gains in weight percentile (B=13.1, p<0.001) and a significant decrease in growth restriction rates over time (B=-1.6, p<0.001). Weight discordance between donor and recipient pairs also significantly decreased over time (linear F(1,42)=54.34, p<0.001).

CONCLUSIONS

After laser surgery for TTTS, donor twins exhibit significant catch-up growth by two years of age.

Effect of resveratrol on metabolic and cardiovascular function in male and female adult offspring exposed to prenatal hypoxia and a high-fat diet

Prenatal hypoxia, a common outcome of pregnancy complications, predisposes offspring to the development of metabolic and cardiovascular disorders in later life. We have previously observed that resveratrol improved cardiovascular and metabolic health in adult male rat offspring exposed to prenatal hypoxia and a postnatal high-fat (HF) diet; however, the effects of resveratrol in female rat offspring are not known. Our aim was to identify the mechanism(s) by which resveratrol may prevent metabolic and cardiac dysfunction in both male and female rat offspring exposed to prenatal hypoxia and a postnatal HF diet. Offspring that experienced normoxia or hypoxia in utero were fed a HF diet or a HF diet supplemented with resveratrol for 9 weeks following weaning. Body composition, metabolic function, in vivo cardiac function and ex vivo cardiac susceptibility to ischaemia-reperfusion (I/R) injury were assessed at 12 weeks of age. Prenatal hypoxia impaired metabolic function in male, but not female, rat offspring fed a HF diet and this was improved by resveratrol supplementation. Prenatal hypoxia also led to reduced recovery from cardiac I/R injury in male, and to a lesser extent in female, rat offspring fed a HF diet. Indices of cardiac oxidative stress after I/R were enhanced in both male and female rat offspring exposed to prenatal hypoxia. Resveratrol improved cardiac recovery from I/R injury and attenuated superoxide levels in both male and female rat offspring. In conclusion, prenatal hypoxia impaired metabolic and cardiac function in a sex-specific manner. Resveratrol supplementation may improve metabolic and cardiovascular health in adult male and female rat offspring exposed to prenatal hypoxia.

Comparison of Two Different Ultrasound Systems for the Evaluation of Tissue Doppler Velocities in Fetuses

Introduction: Recent studies have reported variations of up to 30% between different ultrasound machines for tissue Doppler imaging (TDI), a problem that can significantly impact clinical diagnosis, patient management and research studies. The objective of this study was to assess repeatability and agreement between fetal myocardial peak velocities evaluated by TDI with two different ultrasound systems. Materials and Methods: Systolic (S'), early (E') and late (A') diastolic myocardial peak velocities at mitral and tricuspid annuli as well as at the basal septum were evaluated by spectral TDI in 150 fetuses using two different ultrasound systems: Siemens Antares (Siemens Medical Systems, Malvern, Pa., USA) and Vivid Q (General Electric Healthcare, Horten, Norway). A method comparison study was performed, calculating intraclass correlation coefficients (ICC), and agreement was assessed by Bland-Altman plots. Results: Annular peak velocities showed lower values when measured by Vivid Q compared to values measured by Siemens Antares. ICC ranged from 0.07 (septal S') to 0.33 (right A'), showing very poor repeatability for clinical application. Agreement between the two systems was also poor, with high coefficients of variation for all measurements. Conclusions: Fetal annular peak velocities obtained with different ultrasound systems are not directly comparable. This is consistent with previous data in adults and warrants the need of system-specific reference values, suggesting that the same ultrasound machine should be used for longitudinal follow-up.

Using Satellite-Based Spatiotemporal Resolved Air Temperature Exposure to Study the Association between Ambient Air Temperature and Birth Outcomes in Massachusetts

BACKGROUND

Studies looking at air temperature (Ta) and birth outcomes are rare.

OBJECTIVES

We investigated the association between birth outcomes and daily Ta during various prenatal exposure periods in Massachusetts (USA) using both traditional Ta stations and modeled addresses.

METHODS

We evaluated birth outcomes and average daily Ta during various prenatal exposure periods in Massachusetts (USA) using both traditional Ta stations and modeled address Ta. We used linear and logistic mixed models and accelerated failure time models to estimate associations between Ta and the following outcomes among live births > 22 weeks: term birth weight (≥ 37 weeks), low birth weight (LBW; < 2,500 g at term), gestational age, and preterm delivery (PT; < 37 weeks). Models were adjusted for individual-level socioeconomic status, traffic density, particulate matter ≤ 2.5 μm (PM2.5), random intercept for census tract, and mother's health.

RESULTS

Predicted Ta during multiple time windows before birth was negatively associated with birth weight: Average birth weight was 16.7 g lower (95% CI: -29.7, -3.7) in association with an interquartile range increase (8.4 °C) in Ta during the last trimester. Ta over the entire pregnancy was positively associated with PT [odds ratio (OR) = 1.02; 95% CI: 1.00, 1.05] and LBW (OR = 1.04; 95% CI: 0.96, 1.13).

CONCLUSIONS

Ta during pregnancy was associated with lower birth weight and shorter gestational age in our study population.

Fetal cardiac function in late-onset intrauterine growth restriction vs small-for-gestational age, as defined by estimated fetal weight, cerebroplacental ratio and uterine artery Doppler

OBJECTIVE

Among late-onset small fetuses, a combination of estimated fetal weight (EFW), cerebroplacental ratio (CPR) and mean uterine artery (UtA) pulsatility index (PI) can predict a subgroup of fetuses with poor perinatal outcome; however, the association of these criteria with fetal cardiac structure and function is unknown. Our aim was to determine the presence and severity of signs indicating cardiac dysfunction in small fetuses, classified as intrauterine growth-restricted (IUGR) or small-for-gestational age (SGA), according to EFW, CPR and UtA-PI.

METHODS

A cohort of 209 late-onset small fetuses that were delivered > 34 weeks of gestation was divided in two categories: SGA (n = 59) if EFW was between the 3(rd) and 9(th) centiles with normal CPR and UtA-PI; and IUGR (n = 150) if EFW was < 3(rd) centile, or < 10(th) centile with a CPR < 5(th) centile and/or UtA-PI > 95(th) centile. The small population was compared with 150 appropriately grown fetuses (controls). Fetal cardiac morphometry and function were assessed by echocardiography using two-dimensional M-mode, conventional and tissue Doppler.

RESULTS

Compared with controls, both IUGR and SGA fetuses showed larger and more globular hearts (mean left sphericity index ± SD: controls, 1.8 ± 0.3; SGA, 1.5 ± 0.2; and IUGR, 1.6 ± 0.3; P < 0.01) and showed signs of systolic and diastolic dysfunction, including decreased tricuspid annular plane systolic excursion (mean ± SD: controls, 8.2 ± 1.1; SGA, 7.4 ± 1.2; and IUGR, 6.9 ± 1.1; P < 0.001) and increased left myocardial performance index (mean ± SD: controls, 0.45 ± 0.14; SGA, 0.51 ± 0.08; and IUGR, 0.57 ± 0.1; P < 0.001).

CONCLUSIONS

Despite a perinatal outcome comparable to that of normal fetuses, the population of so-defined SGA fetuses showed signs of prenatal cardiac dysfunction. This supports the concept that at least a proportion of them are not 'constitutionally small' and that further research is needed.

Angiogenic Factors and Doppler Evaluation in Normally Growing Fetuses at Routine Third-Trimester Scan: Prediction of Subsequent Low Birth Weight

Objective: To evaluate in normally growing fetuses at routine 32-36 weeks scan the performance of maternal angiogenic factors, Doppler and ultrasound indices in predicting smallness for gestational age (SGA) at birth. Methods: A cohort of 1,000 singleton pregnancies with normal estimated fetal weight (EFW, ≥10th centile) at 32-36 weeks scan was included. At inclusion, Doppler indices (mean uterine artery pulsatility index [mUtA-PI], cerebroplacental ratio and normalized umbilical vein blood flow by EFW (ml/min/kg) were evaluated, and blood samples were collected and frozen. Nested in this cohort, maternal circulating placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1) were assayed by enzyme-linked immunosorbent assay in all cases with a birth weight <10th centile by customized standards and in an equivalent number of controls (birth weight ≥10th centile). Results: 160 cases were included (80 SGA and 80 controls). EFW (2,128 vs. 2,279 g, p < 0.001), mUtA-PI z-values (-0.25 vs. -0.65, p = 0.034) and sFlt-1/PlGF ratio (11.10 vs. 6.74, p < 0.005) were lower in SGA. The combination of sFlt-1/PlGF ratio and EFW resulted in a 66.3% detection rate for subsequent SGA, with 20% of false-positives. Fetal Doppler indices were not predictive of SGA. Conclusions: In normally growing fetuses, maternal angiogenic factors add to ultrasound parameters in predicting subsequent SGA at birth. This supports further research to investigate composite scores in order to improve the definition and identification of fetal growth restriction.

The emerging epidemic of hypertension in Asian children and adolescents

Hypertension has become a serious global public health burden because of its high incidence and concomitant risk of cardiovascular disease. Many studies have verified that risk factors, such as hypertension and obesity which are responsible for cardiovascular disease, start in early childhood. In Asian countries, the prevalence of hypertension in the pediatric age group has become more prevalent than ever before with the increasing obesity epidemic. To tackle the epidemic of cardiovascular disease, a leading cause of death and disability of non-communicable diseases in Asian countries, population-based measures aiming at reducing harmful environmental factors to blood pressure and body weight must be applied to individuals in their early childhood, as early as the fetal stage. This review focused on the prevalence of pediatric hypertension in Asian countries and outlined several considerations for accurate blood pressure (BP) measurement and evaluation, along with an overview of pathophysiology of fetal programming and obesity related with childhood hypertension.

Dysregulated flow-mediated vasodilatation in the human placenta in fetal growth restriction

Increased vascular resistance and reduced fetoplacental blood flow are putative aetiologies in the pathogenesis of fetal growth restriction (FGR); however, the regulating sites and mechanisms remain unclear. We hypothesised that placental vessels dictate fetoplacental resistance and in FGR exhibit endothelial dysfunction and reduced flow-mediated vasodilatation (FMVD). Resistance was measured in normal pregnancies (n = 10) and FGR (n = 10) both in vivo by umbilical artery Doppler velocimetry and ex vivo by dual placental perfusion. Ex vivo FMVD is the reduction in fetal-side inflow hydrostatic pressure (FIHP) following increased flow rate. Results demonstrated a significant correlation between vascular resistance measured in vivo and ex vivo in normal pregnancy, but not in FGR. In perfused FGR placentas, vascular resistance was significantly elevated compared to normal placentas (58 ± 7.7 mmHg and 36.8 ± 4.5 mmHg, respectively; 8 ml min⁻¹; means ± SEM; P < 0.0001) and FMVD was severely reduced (3.9 ± 1.3% and 9.1 ± 1.2%, respectively). In normal pregnancies only, the highest level of ex vivo FMVD was associated with the lowest in vivo resistance. Inhibition of NO synthesis during perfusion (100 μm l-NNA) moderately elevated FIHP in the normal group, but substantially in the FGR group. Human placenta artery endothelial cells from FGR groups exhibited increased shear stress-induced NO generation, iNOS expression and eNOS expression compared with normal groups. In conclusion, fetoplacental resistance is determined by placental vessels, and is increased in FGR. The latter also exhibit reduced FMVD, but with a partial compensatory increased NO generation capacity. The data support our hypothesis, which highlights the importance of FMVD regulation in normal and dysfunctional placentation.