Blood-Brain Barrier Disintegration in Growth-Restricted Fetuses with Brain Sparing Effect

The endothelial cells of the blood-brain barrier adhere closely, which is provided by tight junctions (TJs). The aim of the study was to assess the damage to the endothelial TJs in pregnancy, complicated by fetal growth restriction (FGR) and circulatory centralization (brain-sparing effect, BS). The serum concentrations of NR1 subunit of the N-methyl-D-aspartate receptor (NR1), nucleoside diphosphate kinase A (NME1), S100 calcium-binding protein B (S100B), occludin (OCLN), claudin-5 (CLN5), and zonula occludens protein – 1 (zo-1), and the placental expressions of OCLN, claudin-4 (CLN4), CLN5, and zo-1 were assessed with ELISA. The significantly higher serum NME1 concentrations and the serum CLN5/zo-1 index were observed in FGR pregnancy with BS, as compared to the FGR group without BS. The FGR newborns with BS were about 20 times more likely to develop an intraventricular hemorrhage (IVH) than the FGR infants without BS. The cerebroplacental ratio (CPR) allowed to predict the IVH in growth-restricted fetuses. The significantly lower placental CLN4 expression was observed in the FGR group with BS and who postnatally developed an IVH, as compared to the growth-restricted infants with BS without IVH signs. Pregnancy complicated by FGR and BS is associated with the destabilization of the fetal blood-brain barrier. The IVH in newborns is reflected in the inhibition of the placental CLN4 expression, which may be a useful marker in the prediction of an IVH among growth-restricted fetuses.

Altered neurodevelopmental DNA methylation status after fetal growth restriction with brain-sparing

It is under debate how preferential perfusion of the brain (brain-sparing) in fetal growth restriction (FGR) relates to long-term neurodevelopmental outcome. Epigenetic modification of neurotrophic genes by altered fetal oxygenation may be involved. To explore this theory, we performed a follow-up study of 21 FGR children, in whom we prospectively measured the prenatal cerebroplacental ratio (CPR) with Doppler sonography. At 4 years of age, we tested their neurodevelopmental outcome using the Wechsler Preschool and Primary Scale of Intelligence, the Child Behavior Checklist, and the Behavior Rating Inventory of Executive Function. In addition, we collected their buccal DNA to determine the methylation status at predefined genetic regions within the genes hypoxia-inducible factor-1 alpha (HIF1A), vascular endothelial growth factor A (VEGFA), erythropoietin (EPO), EPO-receptor (EPOR), brain-derived neurotrophic factor (BDNF), and neurotrophic tyrosine kinase, receptor, type 2 (NTRK2) by pyrosequencing. We found that FGR children with fetal brain-sparing (CPR <1, n = 8) demonstrated a trend (0.05 < p < 0.1) toward hypermethylation of HIF1A and VEGFA at their hypoxia-response element (HRE) compared with FGR children without fetal brain-sparing. Moreover, in cases with fetal brain-sparing, we observed statistically significant hypermethylation at a binding site for cyclic adenosine monophophate response element binding protein (CREB) of BDNF promoter exon 4 and hypomethylation at an HRE located within the NTRK2 promoter (both p <0.05). Hypermethylation of VEGFA was associated with a poorer Performance Intelligence Quotient, while hypermethylation of BDNF was associated with better inhibitory self-control (both p <0.05). These results led us to formulate the hypothesis that early oxygen-dependent epigenetic alterations due to hemodynamic alterations in FGR may be associated with altered neurodevelopmental outcome in later life. We recommend further studies to test this hypothesis.

The effect of maternal position on fetal middle cerebral artery Doppler indices and its association with adverse perinatal outcomes: a pilot study

Objective The aim of this study was to compare position-related changes in fetal middle cerebral artery (MCA) Doppler pulsatility indices (PI). Methods A prospective study of 41 women with conditions associated with placental-pathology (chronic hypertension, pregestational diabetes, and abnormal analytes) and 34 women without those conditions was carried out. Fetal MCA Doppler velocity flow waveforms were obtained in maternal supine and left lateral decubitus positions. MCA PI Δ was calculated by subtracting the PI in the supine position from the PI in the left lateral position. Secondary outcomes included a composite of adverse perinatal outcomes (fetal growth restriction, oligohydramnios, and preeclampsia). χ2 and Student t-tests and repeated-measures analysis of variance were used. Results MCA PI Δ was significantly less for high-risk pregnant women ([P = 0.03]: high risk, left lateral PI, 1.90 ± 0.45 vs. supine PI, 1.88 ± 0.46 [Δ = 0.02]; low risk, left lateral PI, 1.90 ± 0.525 vs. supine PI, 1.68 ± 0.40 [Δ = 0.22]). MCA PI Δ was not significantly different between women who had a composite adverse outcome and women who did not have a composite adverse outcome (P = 0.843). Conclusion Our preliminary study highlights differences in position-related changes in fetal MCA PI between high-risk and low-risk pregnancies. These differences could reflect an attenuated ability of women with certain risk factors to respond to physiologic stress.

Body composition and organ development of intra-uterine growth restricted pigs at weaning

Sow litter sizes have increased, subjecting more small piglets to intra-uterine growth restriction (IUGR). Research on the development and growth of IUGR pigs is limited. The objective of this study was to compare the body composition and organ development of IUGR pigs at weaning, and to estimate their growth performance from birth to 30 kg. A total of 142 IUGR and 142 normal piglets were classified at birth based on their head morphology. At weaning, 20 IUGR and 20 normal piglets were collected, a whole-body dual-energy x-ray absorption scan was performed, and the piglets were euthanized for organ measurements. Body weight (BW) was measured weekly from birth to 30 kg, rectal temperature and whole-blood glucose levels were measured weekly from birth to weaning, and blood samples were collected at days 7, 14 and 21 for IGF-1 analysis. Results showed that IUGR pigs have a similar percentage of adipose tissue (P > 0.05) compared to normal pigs at 24 days of age. Organs were smaller (P < 0.001) in IUGR pigs than in normal pigs, whereas brain, liver, lungs and adrenal glands were relatively larger (P < 0.05) in relation to the BW of IUGR pigs. Average birth weight (BiW) of normal pigs was greater (P < 0.001) compared with IUGR pigs (1.38 v. 0.75 kg), and the average daily gain (ADG) of IUGR pigs was reduced from day 0 to 14, day 0 to 28 (weaning) and from weaning to 30 kg compared to normal pigs. From birth to weaning at day 28, IUGR piglets had a 72.9 g/day greater fractional ADG (FADG) in relation to their BiW (P < 0.05), but FADG did not differ (P > 0.05) from weaning to 30 kg. Rectal temperature of IUGR piglets was greater (P < 0.05) on day 7 compared with normal piglets, and, even though blood glucose levels were decreased (P < 0.001) in IUGR piglets at day 0, neither glucose nor IGF-1 concentrations differed (P > 0.05) between IUGR and normal piglets. In conclusion, IUGR piglets exhibited some relatively larger organs at weaning compared to normal pigs, but body composition was similar between IUGR and normal pigs. In addition, IUGR pigs had a reduced ADG from birth to 30 kg, and, although they exhibited a greater FADG during nursing, IUGR pigs still require six additional days to reach a BW of 30 kg in comparison to normal pigs.