Single-cell atlas of the human brain vasculature across development, adulthood and disease.

A broad range of brain pathologies critically relies on the vasculature, and cerebrovascular disease is a leading cause of death worldwide. However, the cellular and molecular architecture of the human brain vasculature remains incompletely understood1. Here we performed single-cell RNA sequencing analysis of 606,380 freshly isolated endothelial cells, perivascular cells and other tissue-derived cells from 117 samples, from 68 human fetuses and adult patients to construct a molecular atlas of the developing fetal, adult control and diseased human brain vasculature. We identify extensive molecular heterogeneity of the vasculature of healthy fetal and adult human brains and across five vascular-dependent central nervous system (CNS) pathologies, including brain tumours and brain vascular malformations. We identify alteration of arteriovenous differentiation and reactivated fetal as well as conserved dysregulated genes and pathways in the diseased vasculature. Pathological endothelial cells display a loss of CNS-specific properties and reveal an upregulation of MHC class II molecules, indicating atypical features of CNS endothelial cells. Cell-cell interaction analyses predict substantial endothelial-to-perivascular cell ligand-receptor cross-talk, including immune-related and angiogenic pathways, thereby revealing a central role for the endothelium within brain neurovascular unit signalling networks. Our single-cell brain atlas provides insights into the molecular architecture and heterogeneity of the developing, adult/control and diseased human brain vasculature and serves as a powerful reference for future studies.

Estrogen stimulates fetal vascular endothelial growth factor expression and microvascularization.

We recently showed that the ratio of capillaries to myofibers in skeletal muscle, which accounts for 80% of insulin-directed glucose uptake and metabolism, was reduced in baboon fetuses in which estrogen was suppressed by maternal letrozole administration. Since vascular endothelial growth factor (VEGF) promotes angiogenesis, the present study determined the impact of estrogen deprivation on fetal skeletal muscle VEGF expression, capillary development, and long-term vascular and metabolic function in 4- to 8-year-old adult offspring. Maternal baboons were untreated or treated with letrozole or letrozole plus estradiol on days 100-164 of gestation (term = 184 days). Skeletal muscle VEGF protein expression was suppressed by 45% (P < 0.05) and correlated (P = 0.01) with a 47% reduction (P < 0.05) in the number of capillaries per myofiber area in fetuses of baboons in which serum estradiol levels were suppressed 95% (P < 0.01) by letrozole administration. The reduction in fetal skeletal muscle microvascularization was associated with a 52% decline (P = 0.02) in acetylcholine-induced brachial artery dilation and a 23% increase (P = 0.01) in mean arterial blood pressure in adult progeny of letrozole-treated baboons, which was restored to normal by letrozole plus estradiol. The present study indicates that estrogen upregulates skeletal muscle VEGF expression and systemic microvessel development within the fetus as an essential programming event critical for ontogenesis of systemic vascular function and insulin sensitivity/glucose homeostasis after birth in primate offspring.

Maternal tadalafil treatment does not increase uterine artery blood flow or oxygen delivery in the pregnant ewe.

Increasing placental perfusion (PP) could improve outcomes of growth-restricted fetuses. One way of increasing PP may be by using phosphodiesterase (PDE)-5 inhibitors, which induce vasodilatation of vascular beds. We used a combination of clinically relevant magnetic resonance imaging (MRI) techniques to characterize the impact that tadalafil infusion has on maternal, placental and fetal circulations. At 116-117 days' gestational age (dGA; term, 150 days), pregnant ewes (n = 6) underwent fetal catheterization surgery. At 120-123 dGA ewes were anaesthetized and MRI scans were performed during three acquisition windows: a basal state and then ∼15-75 min (TAD 1) and ∼75-135 min (TAD 2) post maternal administration (24 mg; intravenous bolus) of tadalafil. Phase contrast MRI and T2 oximetry were used to measure blood flow and oxygen delivery. Placental diffusion and PP were assessed using the Diffusion-Relaxation Combined Imaging for Detailed Placental Evaluation-'DECIDE' technique. Uterine artery (UtA) blood flow when normalized to maternal left ventricular cardiac output (LVCO) was reduced in both TAD periods. DECIDE imaging found no impact of tadalafil on placental diffusivity or fetoplacental blood volume fraction. Maternal-placental blood volume fraction was increased in the TAD 2 period. Fetal D O 2 ${D_{{{\mathrm{O}}_2}}}$ and V ̇ O 2 ${\dot V_{{{\mathrm{O}}_2}}}$ were not affected by maternal tadalafil administration. Maternal tadalafil administration did not increase UtA blood flow and thus may not be an effective vasodilator at the level of the UtAs. The increased maternal-placental blood volume fraction may indicate local vasodilatation of the maternal intervillous space, which may have compensated for the reduced proportion of UtA D O 2 ${D_{{{\mathrm{O}}_2}}}$ .

Pulmonary vascular reactivity in growth restricted fetuses using computational modelling and machine learning analysis of fetal Doppler waveforms.

The aim of this study was to investigate the pulmonary vasculature in baseline conditions and after maternal hyperoxygenation in growth restricted fetuses (FGR). A prospective cohort study of singleton pregnancies including 97 FGR and 111 normally grown fetuses was carried out. Ultrasound Doppler of the pulmonary vessels was obtained at 24-37 weeks of gestation and data were acquired before and after oxygen administration. After, Machine Learning (ML) and a computational model were used on the Doppler waveforms to classify individuals and estimate pulmonary vascular resistance (PVR). Our results showed lower mean velocity time integral (VTI) in the main pulmonary and intrapulmonary arteries in baseline conditions in FGR individuals. Delta changes of the main pulmonary artery VTI and intrapulmonary artery pulsatility index before and after hyperoxygenation were significantly greater in FGR when compared with controls. Also, ML identified two clusters: A (including 66% controls and 34% FGR) with similar Doppler traces over time and B (including 33% controls and 67% FGR) with changes after hyperoxygenation. The computational model estimated the ratio of PVR before and after maternal hyperoxygenation which was closer to 1 in cluster A (cluster A 0.98 ± 0.33 vs cluster B 0.78 ± 0.28, p = 0.0156). Doppler ultrasound allows the detection of significant changes in pulmonary vasculature in most FGR at baseline, and distinct responses to hyperoxygenation. Future studies are warranted to assess its potential applicability in the clinical management of FGR.

Feasibility of MRI assessment of maternal-fetal oxygen transport and consumption relative to maternal position in healthy late gestational pregnancies.

Late gestational supine positioning reduces maternal cardiac output due to inferior vena caval (IVC) compression, despite increased collateral venous return. However, little is known about the impact of maternal position on oxygen (O2 ) delivery and consumption of the gravid uterus, fetus, placenta and lower limbs. We studied the effects of maternal positioning on these parameters in 20 healthy pregnant subjects at 36 ± 2 weeks using magnetic resonance imaging (MRI); a follow-up MRI was performed 6-months postpartum (n = 16/20). MRI techniques included phase-contrast and T1/T2 relaxometry for blood flow and oximetry imaging, respectively. O2 transport was measured in the following vessels (bilateral where appropriate): maternal abdominal descending aorta (DAoabdo ), IVC, ovarian, paraspinal veins (PSV), uterine artery (UtA) and external iliacs, and umbilical. Maternal cardiac output was measured by summing DAothoracic and superior vena cava flows. Supine mothers (n = 6) had lower cardiac output and O2 delivery in the DAoabdo , UtA and external iliac arteries, and higher PSV flow than those in either the left (n = 8) or right (n = 6) lateral positions during MRI. However, O2 consumption in the gravid uterus, fetus, placenta and lower limbs was unaffected by maternal positioning. The ratio of IVC/PSV flow decreased in supine mothers while ovarian venous flow and O2 saturation were unaltered, suggesting a major route of pelvic venous return unaffected by maternal position. Placental-fetal O2 transport and consumption were similar between left and right lateral maternal positions. In comparison to non-pregnant findings, DAoabdo and UtA O2 delivery and pelvic O2 consumption increased, while lower-limb consumption remained constant , despite reduced external iliac artery O2 delivery in late gestation. KEY POINTS: Though sleeping supine during the third trimester is associated with an increased risk of antepartum stillbirth, the underlying biological mechanisms are not fully understood. Maternal cardiac output and uteroplacental flow are reduced in supine mothers due to inferior vena caval compression from the weight of the gravid uterus. This MRI study provides a comprehensive circulatory assessment, demonstrating reduced maternal cardiac output and O2 delivery (uteroplacental, lower body) in supine compared to lateral positioning; however, O2 consumption (gravid uterus, fetus, placenta, lower limbs) was preserved. Unlike other mammalian species, the ovarian veins conduct substantial venous return from the human pregnant uterus that is unaffected by maternal positioning. Lumbar paraspinal venous flow increased in supine mothers. These observations may have important considerations during major pelvic surgery in pregnancy (i.e. placenta percreta). Future studies should address the importance of maternal positioning as a potential tool to deliver improved perinatal outcomes in pregnancies with compromised uteroplacental O2 delivery.

Assessing the effects of prenatal poly-drug exposure on fetal brain vasculature using optical coherence angiography.

Significance: Maternal exposure to drugs during pregnancy is known to have detrimental effects on the fetus. Alcohol (ethanol) and nicotine are two of the most commonly co-abused substances during pregnancy, and prenatal poly-drug exposure is common due, in part, to the prevalence of unplanned pregnancies. The second trimester is a critical period for fetal neurogenesis and angiogenesis. When drug exposure occurs during this time, fetal brain development is affected. Several behavioral, morphological, and functional studies have evaluated the changes in fetal brain development due to exposure to these drugs individually. However, research on the combined effects of ethanol and nicotine is far more limited, specifically on fetal vasculature changes and development. Aim: We use correlation mapping optical coherence angiography (cm-OCA) to evaluate acute changes in fetal brain vasculature caused by maternal exposure to a combination of ethanol and nicotine. Approach: Ethanol (16.6% v/v, at a dose of 0.75g/kg) and nicotine (at a dose of 0.1 mg/kg) were administered to pregnant mice after initial cm-OCA measurements in utero. Subsequent measurements were taken at 5-min intervals for a total period of 45 min. Results from these experiments were compared to results from our previous studies in which the mother was exposed to only ethanol (dose: 0.75 g/kg) or nicotine (dose: 0.1 mg/kg). Results: While results from exposure to ethanol or nicotine independently showed vasoconstriction, no significant change in vasculature was observed with combined exposure. Conclusion: Results suggested antagonistic effects of ethanol and nicotine on fetal brain vasculature.

Clinical presentation, conventional/4D spatio-temporal image correlation imaging findings, pregnancy and early postnatal outcomes in fetuses having anomalies of systemic venous return in the absence of significant intracardiac defects: A retrospective study from two centres in Southern India.

BACKGROUND: Recent advances in fetal ultrasound imaging, especially four-dimensional (4D) spatio-temporal image correlation techniques permit detailed evaluation of the fetal venous system and its abnormalities. In this report, we present the clinical presentation, conventional/4D spatio-temporal image correlation imaging findings, pregnancy, and early postnatal outcomes in fetuses having anomalies of systemic venous return in the absence of significant intracardiac defects from two centres in southern India. OBJECTIVES: To report the clinical presentation, conventional/4D spatio-temporal image correlation imaging findings, pregnancy, and early postnatal outcomes in fetuses having anomalies of systemic venous return in the absence of significant intracardiac defects from two centres in Southern India. METHODS: Retrospective study (October 2017 to March 2022). All fetuses referred with abnormal cardiac imaging findings who were diagnosed to have anomalies of systemic venous return in the absence of significant intracardiac defects were included. Imaging techniques like 2D with color and 4D spatio-temporal image correlation fetal imaging were used to evaluate systemic venous anomalies. Systemic venous anomalies were grouped into cardinal venous anomalies and umbilico-portosystemic venous anomalies. RESULTS: Thirty-nine fetuses were included; this represented 4.4% of all cardiac anomalies diagnosed during the study period. Cardinal venous anomalies were seen in 29 fetuses (74%); the mean gestation age at diagnosis was 25.5 ± 3.4 weeks. Absent dilated coronary sinus was associated with anomalous drainage of superior caval vein through completely unroofed coronary sinus into the left atrium (n = 3) which resulted in cyanosis after birth in all infants. Among the three cases, one underwent surgery at 6 months of age due to a progressive increase in cyanosis (Spo2 78%) and others are awaiting surgery. A prenatal genetic evaluation was performed in 17 (58.6%). Cardinal venous anomalies were not associated with genetic abnormalities. Live births occurred in all fetuses with cardinal venous anomalies. Umbilico-portosystemic venous anomalies were seen in 10 (26%). The mean gestation age at diagnosis was 26.5 ± 4.5 weeks. Except in a fetus with the extrahepatic portosystemic shunt (umbilical vein to iliac vein), the genetic evaluation was normal in our cohort. Extracardiac anomalies (n = 3/10; 30%) were seen in both intra (n = 1) and extrahepatic portosystemic shunts (n = 2). CONCLUSION: Anomalies of systemic venous return in the absence of significant intracardiac, extracardiac, and genetic abnormalities carried an overall favorable prognosis in our cohort. Precise characterization of anatomic details using advanced imaging techniques helps in the understanding of this complex three-dimensional anatomy and in the prognostication of these anomalies.

The effect of middle cerebral artery peak systolic velocity on prognosis in early and late-onset fetal growth restriction.

OBJECTIVES: We aim to investigate the utility of middle cerebral artery peak systolic velocity (MCA PSV) Doppler in determining the perinatal mortality and morbidity in serial Doppler measurements from the time of diagnosis to the delivery of complicated cases with fetal growth restriction (FGR). METHODS: At 24-38 weeks of gestation, 65 pregnant women diagnosed with FGR were included in the study. The fetal biometry measurements, MCA pulsatility index (PI), and MCA PSV Doppler evaluation of the cases formed at the diagnosis and the delivery were recorded. Gestational weeks, birth weights, APGAR scores, cord pH values, NICU (neonatal intensive care unit) admission, NICU duration of stay, and perinatal morbidity parameters such as RDS (respiratory distress syndrome), BPD (bronchopulmonary dysplasia), NEC (necrotizing enterocolitis), sepsis and perinatal mortality were compared. The patients were divided into two groups: early and late-onset fetal growth restriction. Perinatal morbidity and mortality were accepted as adverse perinatal outcomes. RESULTS: MCA PSV above the 95th percentile at the diagnosis and delivery time was seen at a significantly higher rate with adverse perinatal outcomes. CONCLUSIONS: This study shows that evaluating MCA PSV with Doppler can be a helpful diagnostic method for early diagnosis of restriction and hypoxic fetuses. Also, it may be used in clinics as a noninvasive method to predict neonatal prognosis.

Fisiología respiratoria: el pulmón al momento de nacer / Respiratory Physiology - the lung at the moment of birth

La adaptación fisiológica de los recién nacidos de la vida intrauterina a la extrauterina incluye cambios fisiológicos complejos. Para que se complete con éxito la transición fetal a neonatal, los recién nacidos deben lograr el aclaramiento de líquido pulmonar, la generación de CRF e inicio de la respiración, para permitir el intercambio de gases y la oxigenación de los tejidos. En este artículo se describen estos mecanismos, algunas bases del desarrollo pulmonar y de la circulación fetal; y las medidas que se requieren para asistir al recién nacido cuando no logran completar esta transición espontáneamente, lo que ocurre en el 5 al 10 % de los casos.

The physiological adaptation of newborns from intrauterine to extrauterine life includes complex physiological changes. For the fetal to neonatal transition to be successfully completed, neonates must achieve lung fluid clearance, FRC generation, and initiation of respiration to allow gas exchange and tissue oxygenation. This article describes these mechanisms, some bases of lung development and fetal circulation; and the measures required to assist the newborn, when they fail to complete this transition spontaneously, which occurs in the 5 to 10% of cases.

Late-term fetuses with reduced umbilical vein blood flow volume: An under-recognized population at increased risk of growth restriction.

OBJECTIVES: To investigate the umbilical vein and uterine arteries blood flow volume (UV-Q, UtA-Q) in late-term pregnancies. STUDY DESIGN: This was a prospective observational cohort study of singleton pregnancies ≥40 + 0 weeks in which UV-Q and UtA-Q, both absolute and normalized for estimated fetal weight (EFW) values, were evaluated in relation to AC drop of ≥20 percentiles from 20 weeks to term, Doppler signs of fetal cerebral blood flow redistribution and composite adverse perinatal outcome. The presence of neonatal hypoglycaemia and the need of formula milk supplementation were also examined. RESULTS: The study population comprised 200 women. Fetuses with AC drop (n = 34) had a significantly lower UV-Q and UV-Q/EFW than fetuses without AC drop (n = 166): median UV-Q 184 ml/min (IQR 143-225) vs 233 ml/min (IQR 181-277), p = 0.0006; median UV-Q/EFW 55 ml/min/kg (IQR 42-66) vs 63 ml/min/kg (IQR 48-74), p = 0.03. Fetuses with cerebral blood flow redistribution (n = 48) had a significantly lower UV-Q and UV-Q/EFW than those without (n = 134): median UV-Q 210 ml/min (IQR 155-263) vs 236 ml/min (IQR 184-278), p = 0.04; median UV-Q/EFV 58 ml/min/kg (IQR 45-70) vs 65 ml/min/kg (IQR 50-76), p = 0.04. There was a significant moderate correlation between middle cerebral artery pulsatility index (MCA-PI) and UV-Q and UV-Q/EFW (Spearman Rho -0.20 and -0.20; p = 0.008 and p = 0.006). CONCLUSIONS: The umbilical vein blood flow volume might have a potential role to identify fetuses with stunted growth in late-term pregnancies.

Brain Doppler abnormalities in fetuses with open spina bifida.

BACKGROUND: To describe the brain Doppler changes in fetuses with isolated open spina bifida (OSB). STUDY DESIGN: Doppler ultrasound measurements including the umbilical artery (UA) pulsatility index (PI), middle cerebral artery (MCA) PI, and their combination into the cerebroplacental ratio (CPR) and umbilicocerebral ratio (UCR) were performed in a cohort of fetuses with OSB. Included patients were individually matched to a control group without structural anomalies and similar gestational ages. MCA-PI and/or CPR values below the 5th centile were considered abnormal and indicative of cerebral blood redistribution, while UCR and UA-PI above the 95th centile were considered abnormal. RESULTS: During the study period, 266 fetuses were recruited, 133 normally grown fetuses with OSB and 133 matched controls. Doppler recordings were successfully obtained in all fetuses at a median gestational age of 30.9 weeks. All cases showed UA-PI within normal ranges, but fetuses with OSB showed significantly higher frequency of cerebral blood redistribution (15.0 vs. 3.0%, p < .01), MCA-PI <5th centile (10.5% vs. 3.0%, p = .01), decreased CPR (9.8% vs. 2.3%, p = .01) and increased UCR (17.2 % vs 7.5 %, p =.02). The rate of cerebral blood redistribution was significantly higher in the OSB group with ventriculomegaly in comparison to those with OSB and normal lateral ventricle diameter (18.6% vs. 3.2%, respectively; p <.05). CONCLUSION: A proportion of fetuses with isolated open spina bifida showed cerebral blood redistribution.

Adverse perinatal outcomes in fetuses with severe late-onset fetal growth restriction.

OBJECTIVE: To evaluate perinatal outcomes in fetuses with severe late-onset fetal growth restriction. METHODS: This was a retrospective and observational cohort study in which pregnant women diagnosed with late-onset fetal growth restriction assisted at perinatal maternity birth from 2010 to 2017 were included. The outcomes were intensive care unit (ICU) admission and perinatal complications, such as neonatal death, intraventricular hemorrhage, periventricular leukomalacia, hypoxic-ischemic encephalopathy, necrotizing enterocolitis, bronchopulmonary dysplasia, and sepsis. RESULTS: We selected 277 pregnant women, of whom 124 newborns (44.76%) went to the ICU. The chance of a newborn needing ICU decreases by 62, 7, and 9% according to an increase of one gestational week, 1 cm of the abdominal circumference, or 1 cm of the amniotic fluid index, respectively. Oligohydramnios increases the risk of going to the ICU by 2.13 times. The increase in the umbilical artery pulsatility index (PI) Doppler increases the chance of ICU admission by 7.9 times. The normal middle cerebral artery PI Doppler and the normal cerebroplacental ratio reduce the risk of ICU admission. CONCLUSION: The estimated fetal weight, abdominal circumference, and amniotic fluid index diagnosed severe late-onset fetal growth restriction. With the decrease in middle cerebral artery PI Doppler, there is a greater probability of admission to the ICU, with the most common complications being intraventricular hemorrhage and necrotizing enterocolitis.

Impact of fetal trisomy 21 on umbilical artery Doppler indices.

OBJECTIVES: Umbilical artery (UA) Doppler indices are surrogate measures of placental function, most commonly used to assess fetal wellbeing in pregnancies with fetal growth restriction. Fetuses with trisomy 21 (t21) are reported to have elevated UA Doppler indices, but reference percentiles are currently lacking for this population. We hypothesized that gestational age-specific values of UA Doppler indices in pregnancies complicated by t21 will be elevated compared to established percentiles based on euploid pregnancies. We aimed to assess UA Doppler indices longitudinally in fetuses with t21 in order to demonstrate Doppler patterns across gestation in this population, compare them with euploid fetuses, and investigate their association with pregnancy outcomes. METHODS: We conducted a retrospective cohort study of singleton pregnancies with confirmed fetal t21 who underwent UA Doppler surveillance antenatally from January 2012 to August 2019. UA Doppler indices, including systolic/diastolic (S/D) ratio, pulsatility index (PI), and resistance index (RI) were extracted from ultrasound reports or directly from ultrasound images. UA S/D, PI, and RI percentiles by gestational week were created from available observations from our cohort via a data-driven approach using a generalized additive model. A secondary analysis was run to statistically compare t21 values to established percentiles based on observations from a historical population of euploid fetuses. RESULTS: UA Doppler measurements from 86 t21 fetuses and 130 euploid fetuses were included in our analysis. Median (IQR) maternal age in t21 pregnancies and euploid pregnancies were 35 years (29-38) and 30 years (27-33), respectively. As in euploid fetuses, we found a negative association between Doppler indices and gestational age in the t21 fetuses. Maternal tobacco use, obesity, or chronic hypertension had no significant effect on UA Doppler indices. As hypothesized, values for UA S/D ratio, PI, and RI at the 2.5th, 5th, 10th, 25th, 50th, 75th, 90th, 95th, and 97.5th percentiles by gestational week were significantly higher in t21 fetuses compared to euploid fetuses (p<.001). Overall, 55.8% (48/86) of the t21 fetuses demonstrated at least one Doppler value above the 95th percentile for gestational age based on euploid reference standard. At birth, eight (9.3%) of the t21 fetuses were small for gestational age. When these pregnancies were removed from analysis, UA Doppler indices remained significantly higher than established percentiles at each week of gestation (p < .001). Only three pregnancies ended in fetal demise in the t21 population, two of which had persistently elevated Dopplers above the 95th percentile per established reference percentiles. CONCLUSIONS: At each week of gestation, UA Doppler indices in t21 fetuses were significantly higher than established percentiles from a euploid population. Reference intervals based on euploid fetuses may therefore not be appropriate for antenatal surveillance of fetuses with t21. Prospective studies are needed to investigate the role and impact of serial UA Doppler velocimetry in the surveillance of pregnancies complicated by fetal t21.

Prenatal cardiac biometry and flow assessment in fetuses with bicuspid aortic valve at 20 weeks' gestation: multicenter cohort study.

OBJECTIVE: To investigate prenatal changes in cardiac biometric and flow parameters in fetuses with bicuspid aortic valve (BAV) diagnosed neonatally compared with controls with normal cardiac anatomy. METHODS: This analysis was conducted as part of the Copenhagen Baby Heart Study, a multicenter cohort study of 25 556 neonates that underwent second-trimester anomaly scan at 18 + 0 to 22 + 6 weeks' gestation and neonatal echocardiography within 4 weeks after birth, in Copenhagen University Hospital Herlev, Hvidovre Hospital and Rigshospitalet in greater Copenhagen, between April 2016 and October 2018. From February 2017 (Rigshospitalet) and September 2017 (Herlev and Hvidovre hospitals), the protocol for second-trimester screening of the heart was extended to include evaluation of the four-chamber view, with assessment of flow across the atrioventricular valves, sagittal view of the aortic arch and midumbilical artery and ductus venosus pulsatility indices. All images were evaluated by two investigators, and cardiac biometric and flow parameters were measured and compared between cases with BAV and controls. All cases with neonatal BAV were assessed by a specialist. Maternal characteristics and first- and second-trimester biomarkers were also compared between the two groups. RESULTS: Fifty-five infants with BAV and 8316 controls with normal cardiac anatomy were identified during the study period and assessed using the extended prenatal cardiac imaging protocol. There were three times as many mothers who smoked before pregnancy in the group with BAV as in the control group (9.1% vs 2.7%; P = 0.003). All other baseline characteristics were similar between the two groups. Fetuses with BAV, compared with controls, had a significantly larger diameter of the aorta at the level of the aortic valve (3.1 mm vs 3.0 mm (mean difference, 0.12 mm (95% CI, 0.03-0.21 mm))) and the pulmonary artery at the level of the pulmonary valve (4.1 mm vs 3.9 mm (mean difference, 0.15 mm (95% CI, 0.03-0.28 mm))). Following conversion of the diameter measurements of the aorta and pulmonary artery to Z-scores and Bonferroni correction, the differences between the two groups were no longer statistically significant. Pregnancy-associated plasma protein-A (PAPP-A) multiples of the median (MoM) was significantly lower in the BAV group than in the control group (0.85 vs 1.03; P = 0.04). CONCLUSIONS: Our findings suggest that fetuses with BAV may have a larger aortic diameter at the level of the aortic valve, measured in the left-ventricular-outflow-tract view, and a larger pulmonary artery diameter at the level of the pulmonary valve, measured in the three-vessel view, at 20 weeks' gestation. Moreover, we found an association of maternal smoking and low PAPP-A MoM with BAV. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Insulin-like growth factor 1 signaling in the placenta requires endothelial nitric oxide synthase to support trophoblast function and normal fetal growth.

Currently, there is no effective treatment for placental dysfunction in utero. In a ligated mouse model of fetal growth restriction (FGR), nanoparticle-mediated human insulin-like 1 growth factor (hIGF1) gene delivery (NP-Plac1-hIGF1) increased hIGF1 expression and maintained fetal growth. However, whether it can restore fetal growth remains to be determined. Using the endothelial nitric oxide synthase knockout (eNOS-/-) mouse model, a genetic model of FGR, we found that despite inducing expression of hIGF1 in the placentas treated with NP-Plac1-hIGF1 (P = 0.0425), FGR did not resolve. This was associated with no change to the number of fetal capillaries in the placental labyrinth; an outcome which was increased with NP-Plac1-hIGF1 treatment in the ligated mouse model, despite increased expression of angiopoietin 1 (P = 0.05), and suggested IGF1 signaling in the placenta requires eNOS to modulate placenta angiogenesis. To further assess this hypothesis, BeWo choriocarcinoma cell line and human placental explant cultures were treated with NP-Plac1-hIGF1, oxidative stress was induced with hydrogen peroxide (H2O2), and NOS activity was inhibited using the inhibitor NG-monomethyl-l-arginine (l-NMMA). In both BeWo cells and explants, the protective effect of NP-Plac1-hIGF1 treatment against H2O2-induced cell death/lactate dehydrogenase release was prevented by eNOS inhibition (P = 0.003 and P < 0.0001, respectively). This was associated with an increase in mRNA expression of oxidative stress markers hypoxia inducing factor 1α (HIF1α; P < 0.0001) and ADAM10 (P = 0.0002) in the NP-Plac1-hIGF1 + H2O2 + l-NMMA-treated BeWo cells. These findings show for the first time the requirement of eNOS/NOS in IGF1 signaling in placenta cells that may have implications for placental angiogenesis and fetal growth.

Improvement in fetal pulmonary hypertension and maturity after reversal of ductal constriction: prospective cohort study.

OBJECTIVES: To test the hypotheses that estimated mean pulmonary arterial pressure (MPAP) decreases and pulmonary vascular maturation, assessed by the ratio of pulmonary arterial flow acceleration time to ejection time (AT/ET ratio), increases after reversal of fetal ductus arteriosus constriction by reducing maternal intake of the causal agent (prostaglandin inhibitors, such as polyphenol-rich foods or non-steroidal anti-inflammatory drugs), and that these effects are independent of gestational age, which are inferences not yet demonstrated in the clinical setting. METHODS: This was a prospective cohort study comparing Doppler echocardiographic ductal flow dynamics, MPAP and pulmonary arterial flow AT/ET ratio in third-trimester fetuses (≥ 28 weeks' gestation) with ductus arteriosus constriction, at the time of diagnosis and after 2 weeks of reduced maternal intake of prostaglandin inhibitors either by suspending the use of pharmacological agents with potential for prostaglandin inhibition or by restricting the consumption of polyphenol-rich foods. MPAP was estimated using the Dabestani equation (MPAP = 90 - (0.62 × AT)), and pulmonary vascular maturity was assessed using the AT/ET ratio, according to reported validation studies. Student's t-test was used for comparison of variables at diagnosis with those after reversal of ductal constriction. Change in MPAP and pulmonary AT/ET ratio between the two assessments was compared with the expected change in the same gestational period in normal fetuses based on reference curves of MPAP and pulmonary AT/ET ratio constructed in normal fetuses from healthy pregnant women at 19-37 weeks' gestation, encompassing the same gestational age range as the study group (28-37 weeks). RESULTS: Seventy pregnancies with fetal ductus arteriosus constriction were included in the study. After 2 weeks of reduced maternal intake of prostaglandin inhibitors, normalization of mean systolic (change from 1.86 ± 0.34 m/s at diagnosis to 1.38 ± 0.41 m/s; P < 0.001) and diastolic (change from 0.41 ± 0.11 m/s to 0.21 ± 0.065 m/s; P < 0.001) ductal velocities and of mean pulsatility index (change from 1.99 ± 0.20 to 2.55 ± 0.42; P < 0.001) was demonstrated. MPAP decreased between the assessments (change from 66.7 ± 6.90 mmHg at diagnosis to 54.5 ± 6.70 mmHg after 2 weeks; P < 0.001) and mean pulmonary AT/ET ratio increased (change from 0.20 ± 0.06 to 0.33 ± 0.07; P < 0.001). Change in MPAP between diagnosis and after 2 weeks of reduced maternal intake of prostaglandin inhibitors was -12.2 ± 0.30 mmHg, which was 5.3-times higher than that in 305 normal fetuses over 2 weeks during the same gestational period (-2.3 ± 0.19 mmHg) (P < 0.001), and change in pulmonary AT/ET ratio between the two assessments was 0.13 ± 0.08, which was 8.7-times higher than that in normal fetuses in the same gestational period (0.015 ± 0.08) (P < 0.001). CONCLUSIONS: Resolution of fetal ductal constriction is followed by a fall in MPAP and by an increase in pulmonary vascular maturity, to a significantly greater degree than is observed in normal fetuses in the same gestational-age period. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Prediction of post-laser fetal death in selective growth restriction complicating twin-twin transfusion syndrome using standardized definitions.

OBJECTIVE: Selective fetal growth restriction (sFGR) complicating twin-twin transfusion syndrome (TTTS) is associated with a 3-6-fold increased risk of fetal demise after fetoscopic laser surgery (FLS). Identifying these patients is challenging due to varying definitions of sFGR used in the literature. The objective of this study was to determine the association of three currently used definitions for sFGR with demise of the smaller twin, typically the donor, following FLS for TTTS. METHODS: This was a retrospective cohort study of monochorionic diamniotic twin pregnancies undergoing FLS for TTTS between January 2015 and December 2018. Classification of the cohort as sFGR or non-sFGR was performed using three different definitions: (1) estimated fetal weight (EFW) of one twin < 10th centile and intertwin EFW discordance > 25%, according to the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) (Definition A); (2) EFW of one twin < 3rd centile, according to the solitary criterion for sFGR reported in a Delphi consensus (Definition B); and (3) presence of at least two of four of the following criteria: EFW of one twin < 10th centile, abdominal circumference of one twin < 10th centile, intertwin EFW discordance of ≥ 25% and umbilical artery pulsatility index of the smaller twin > 95th centile, according to the contributory criteria for sFGR in monochorionic diamniotic twin pregnancies reported in the Delphi consensus (Definition C). Pearson's χ2 and univariate and multivariate logistic regression analyses were performed to assess the association of classification as sFGR according to the different definitions with fetal demise within 48 h after FLS. RESULTS: A total of 124 pregnancies underwent FLS for TTTS during the study period. Of these, 46/124 (37.1%) were identified as having sFGR according to the ISUOG criteria (Definition A), 57/124 (46.0%) based on EFW < 3rd centile (Definition B) and 70/124 (56.5%) according to the Delphi contributory criteria (Definition C). There were no differences in maternal body mass index, recipient twin amniotic fluid volume, gestational age (GA) at intervention or GA at delivery between sFGR and non-sFGR cases for any of the three definitions. There were also no differences in the rates of postprocedure recipient demise or Doppler abnormalities in the recipient. Regardless of the definition used, sFGR cases showed a significantly higher rate of postprocedure donor twin demise compared with that in non-sFGR cases (Definition A: 28.3% vs 3.8%, P < 0.01; Definition B: 22.8% vs 4.5%, P = 0.02; Definition C: 22.9% vs 0%, P < 0.01). For all of the sFGR definitions, the rate of Stage-III TTTS was increased in sFGR compared to non-sFGR cases (Definition A: 65.2% vs 35.9%, P ≤ 0.01; Definition B: 59.6% vs 35.8%, P = 0.04; Definition C: 62.9% vs 25.9%, P < 0.01). All cases of donor demise met the criteria for sFGR according to Definition C. Classification as sFGR according to Definition C was associated with a significantly higher rate of post-FLS donor demise compared to Definitions A and B (χ2 , 15.32; P < 0.01). Logistic regression analysis demonstrated that sFGR cases had an increased risk of donor demise (Definition A: odds ratio (OR), 4.97 (95% CI, 1.77-13.94), P < 0.01; Definition B: OR, 4.39 (95% CI, 1.36-14.15), P = 0.01) and that staging of TTTS was also predictive of demise (OR, 2.26 (95% CI, 1.14-4.47), P = 0.02). After adjusting for GA at intervention and stage of TTTS, the results were similar (Definition A: OR, 6.48 (95% CI, 2.11-24.56), P = 0.002; Definition B: OR, 4.16 (95% CI, 1.35-15.74), P = 0.02). CONCLUSIONS: The rate of fetal demise following FLS for TTTS is increased in the presence of sFGR. Improving diagnosis of sFGR should improve counseling and may affect management. The Delphi method of defining sFGR based on the presence of at least two of four contributory criteria had the highest predictive value for donor demise following FLS for TTTS. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Fetal-placental blood flow and neurodevelopment in childhood: population-based neuroimaging study.

OBJECTIVE: Antenatal Doppler measurements of the fetal umbilical and cerebral circulations can predict perinatal complications; however, it is unclear if subtle variations in antenatal Doppler measurements are associated with long-term neurodevelopmental outcome. In this study, we examined whether antenatal Doppler measurements of the fetal-placental circulation are associated with cognitive and motor abilities and brain morphology in childhood. METHODS: To evaluate differences in long-term sequelae across the continuum of the umbilical and cerebral artery circulations in the general population, we utilized a population-based longitudinal cohort study approach. In women from the Generation R study, we measured second- and third-trimester umbilical artery pulsatility index (UA-PI). Children underwent non-verbal intelligence testing at 4-8 years of age, and at 8-12 years they underwent finger-tapping tests to measure fine motor skills, balance beam tests to measure gross motor skills and brain magnetic resonance imaging. We assessed the relationships between prenatal UA-PI and neurodevelopmental outcome using linear regression. We adjusted for child age and sex, maternal age, education, parity and smoking status. RESULTS: The study sample included 2803 pregnancies. Higher third-trimester UA-PI was associated with poorer fine motor performance (0.41 (95% CI, 0.11-0.70) fewer taps on the finger-tapping test per 1 SD higher UA-PI) and gross motor performance (0.64 (95% CI, 0.20-1.08) fewer steps on the balance beam test per 1 SD higher UA-PI). One SD higher third-trimester UA-PI was also associated with 0.65 (95% CI, 0.04-1.25) points lower intelligence quotient; however, unlike the associations with motor abilities, this finding did not persist after correction for multiple testing. Higher second-trimester UA-PI was associated with smaller brain volume (6.1 (95% CI, 1.0-11.3) cm3 reduction per 1 SD higher UA-PI), but the association did not persist after correction for multiple testing. CONCLUSION: Higher placental vascular resistance may have mild adverse effects on neurodevelopmental outcome at school age. While these effects are subtle at population level, we encourage future research into the role of early circulation in brain development. This information could be used to develop targeted interventions. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Fetal cardiac function at 35-37 weeks' gestation in pregnancies that subsequently develop pre-eclampsia.

OBJECTIVE: To compare fetal cardiac morphology and function between pregnancies that subsequently developed pre-eclampsia (PE) and those that remained normotensive. METHODS: This was a prospective observational study in 1574 pregnancies at 35-37 weeks' gestation, including 76 that subsequently developed PE. We carried out comprehensive assessment of fetal cardiac morphology and function including novel imaging modalities, such as speckle-tracking echocardiography, and measured uterine artery pulsatility index, mean arterial pressure (MAP), serum placental growth factor (PlGF), soluble fms-like tyrosine kinase-1 (sFlt-1) and cerebroplacental ratio (CPR). The findings in the group that subsequently developed PE were compared to those in pregnancies that remained normotensive. RESULTS: In fetuses of mothers who subsequently developed PE, compared to those from normotensive pregnancies, there was a more globular right ventricle, as shown by reduced right ventricular sphericity index, reduced right ventricular systolic contractility, as shown by reduced global longitudinal strain, and reduced left ventricular diastolic function, as shown by increased E/A ratio. On multivariable regression analysis, these indices demonstrated an association with PE, independent of maternal characteristics and fetal size. In pregnancies that subsequently developed PE, compared to those that remained normotensive, MAP, sFlt-1 and the incidence of low birth weight were higher, whereas serum PlGF, CPR and the interval between assessment and delivery were lower. These findings demonstrate that, in pregnancies that develop PE, there is evidence of impaired placentation, reflected in low PlGF and reduced birth weight, placental ischemia, evidenced by increased sFlt-1 which becomes apparent in the interval of 2-4 weeks preceding the clinical onset of PE, and consequent fetal hypoxia-induced redistribution in the fetal circulation, reflected in the low CPR. CONCLUSION: Although the etiology of the observed fetal cardiac changes in pregnancies that subsequently develop PE remains unclear, it is possible that the reduction in right-heart systolic function is the consequence of high afterload due to increased placental resistance, whilst the early left ventricular diastolic changes could be due to fetal hypoxia-induced redistribution in the fetal circulation. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.