Heightened activation of embryonic megakaryocytes causes aneurysms in the developing brain of mice lacking podoplanin.

During early embryonic development in mammals, including humans and mice, megakaryocytes (Mks) first originate from primitive hematopoiesis in the yolk sac. These embryonic Mks (eMks) circulate in the vasculature with unclear function. Herein, we report that podoplanin (PDPN), the ligand of C-type lectin-like receptor (CLEC-2) on Mks/platelets, is temporarily expressed in neural tissue during midgestation in mice. Loss of PDPN or CLEC-2 resulted in aneurysms and spontaneous hemorrhage, specifically in the lower diencephalon during midgestation. Surprisingly, more eMks/platelets had enhanced granule release and localized to the lower diencephalon in mutant mouse embryos than in wild-type littermates before hemorrhage. We found that PDPN counteracted the collagen-1-induced secretion of angiopoietin-1 from fetal Mks, which coincided with enhanced TIE-2 activation in aneurysm-like sprouts of PDPN-deficient embryos. Blocking platelet activation prevented the PDPN-deficient embryo from developing vascular defects. Our data reveal a new role for PDPN in regulating eMk function during midgestation.

Prevalence of COL4A1 and COL4A2 mutations in severe fetal multifocal hemorrhagic and/or ischemic cerebral lesions.

OBJECTIVE: To establish the prevalence of COL4A1 and COL4A2 gene mutations in fetuses presenting with a phenotype suggestive of cerebral injury. METHODS: This was a single-center retrospective analysis of all cases of fetal cerebral anomalies suggestive of COL4A1 or COL4A2 gene mutation over the period 2009-2018. Inclusion criteria were: (1) severe and/or multifocal hemorrhagic cerebral lesions; (2) multifocal ischemic-hemorrhagic cerebral lesions. These anomalies could be of different ages and associated with schizencephaly or porencephaly. Between fetuses with and those without a mutation, we compared gestational age at the time of diagnosis, parity and fetal gender. RESULTS: Among the 956 cases of cerebral anomaly diagnosed in our center during the 10-year study period, 18 fetuses were identified for inclusion. A pathogenic COL4A1 gene mutation was found in five of these cases, among which four were de-novo mutations. A variant of unknown significance was found in four fetuses: in the COL4A1 gene in one case and in the COL4A2 gene in three cases. No COL4A1 or COL4A2 mutation was found in the remaining nine fetuses. The median (interquartile range) gestational age at diagnosis was significantly lower in cases with a mutation (24 (22-26) weeks) than in cases without a mutation (32 (29.5-34.5) weeks) (P = 0.03). CONCLUSIONS: A phenotype suggestive of cerebral injury was found in 18 of the 956 (1.9%) cases in our population, in 28% of which there was an associated COL4A1 or COL4A2 mutation. COL4A1 and COL4A2 gene mutations should be sought systematically in cases of severe and/or multifocal hemorrhagic or ischemic-hemorrhagic cerebral lesions, with or without schizencephaly or porencephaly. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Trends in hospitalization of preterm infants with intraventricular hemorrhage and hydrocephalus in the United States, 2000-2010.

OBJECT Even with improved prenatal and neonatal care, intraventricular hemorrhage (IVH) occurs in approximately 25%-30% of preterm infants, with a subset of these patients developing hydrocephalus. This study was undertaken to describe current trends in hospitalization of preterm infants with posthemorrhagic hydrocephalus (PHH) using the Nationwide Inpatient Sample (NIS) and the Kids' Inpatient Database (KID). METHODS The KID and NIS were combined to generate data for the years 2000-2010. All neonatal discharges with ICD-9-CM codes for preterm birth with IVH alone or with IVH and hydrocephalus were included. RESULTS There were 147,823 preterm neonates with IVH, and 9% of this group developed hydrocephalus during the same admission. Of patients with Grade 3 and 4 IVH, 25% and 28%, respectively, developed hydrocephalus in comparison with 1% and 4% of patients with Grade 1 and 2 IVH, respectively. Thirty-eight percent of patients with PHH had permanent ventricular shunts inserted. Mortality rates were 4%, 10%, 18%, and 40%, respectively, for Grade 1, 2, 3, and 4 IVH during initial hospitalization. Length of stay has been trending upward for both groups of IVH (49 days in 2000, 56 days in 2010) and PHH (59 days in 2000, 70 days in 2010). The average hospital cost per patient (adjusted for inflation) has also increased, from $201,578 to $353,554 (for IVH) and $260,077 to $495,697 (for PHH) over 11 years. CONCLUSIONS The number of neonates admitted with IVH has increased despite a decrease in the number of preterm births. Rates of hydrocephalus and mortality correlated closely with IVH grade. The incidence of hydrocephalus in preterm infants with IVH remained stable between 8% and 10%. Over an 11-year period, there was a progressive increase in hospital cost and length of stay for preterm neonates with IVH and PHH that may be explained by a concurrent increase in the proportion of patients with congenital cardiac anomalies.

The 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) pathway regulates developmental cerebral-vascular stability via prenylation-dependent signalling pathway.

Spontaneous intracranial hemorrhage is a debilitating form of stroke, often leading to death or permanent cognitive impairment. Many of the causative genes and the underlying mechanisms implicated in developmental cerebral-vascular malformations are unknown. Recent in vitro and in vivo studies in mice have shown inhibition of the 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) pathway to be effective in stabilizing cranial vessels. Using a combination of pharmacological and genetic approaches to specifically inhibit the HMGCR pathway in zebrafish (Danio rerio), we demonstrate a requirement for this metabolic pathway in developmental vascular stability. Here we report that inhibition of HMGCR function perturbs cerebral-vascular stability, resulting in progressive dilation of blood vessels, followed by vessel rupture, mimicking cerebral cavernous malformation (CCM)-like lesions in humans and murine models. The hemorrhages in the brain are rescued by prior exogenous supplementation with geranylgeranyl pyrophosphate (GGPP), a 20-carbon metabolite of the HMGCR pathway, required for the membrane localization and activation of Rho GTPases. Consistent with this observation, morpholino-induced depletion of the ß-subunit of geranylgeranyltransferase I (GGTase I), an enzyme that facilitates the post-translational transfer of the GGPP moiety to the C-terminus of Rho family of GTPases, mimics the cerebral hemorrhaging induced by the pharmacological and genetic ablation of HMGCR. In embryos with cerebral hemorrhage, the endothelial-specific expression of cdc42, a Rho GTPase involved in the regulation of vascular permeability, was significantly reduced. Taken together, our data reveal a metabolic contribution to the stabilization of nascent cranial vessels, requiring protein geranylgeranylation acting downstream of the HMGCR pathway.

Role of foetal MRI in the evaluation of ischaemic-haemorrhagic lesions of the foetal brain.

OBJECTIVE: The purpose of this study is to define the role of foetal magnetic resonance imaging (MRI) in evaluating cerebral ischaemic-haemorrhagic lesions and the extension of parenchymal injuries. STUDY DESIGN: From September 2006 to September 2010, 271 foetal MRI have been performed on cases referred to us for ultrasound suspect of brain abnormalities or cytomegalovirus infection and Toxoplasma serum conversion. Foetal MRI was performed with a 1.5-T magnet system without mother sedation. RESULTS: Foetal MRI detected ischaemic-haemorrhagic lesions in 14 of 271 foetuses, consisting of 5% incidence. MRI confirmed the diagnosis in three of 14 cases with ultrasonography (US) suspect of ischaemic-haemorrhagic lesions associated with ventriculomegaly. In one of 14 cases with US findings of cerebellar haemorrhage, MRI confirmed the diagnosis and provided additional information regarding the parenchymal ischaemic injury. In eight of 14 cases with US suspect of ventriculomegaly (3), corpus callosum agenesis (2), hypoplasia of cerebellar vermis (1), holoprosencephaly (1) and spina bifida (1), MRI detected ischaemic and haemorrhagic lesions unidentified at US examination. In two of 14 foetuses with US suspect of intracerebral space-occupying lesion, MRI modified the diagnosis to extra-axial haematoma associated with dural sinus malformation. Results were compared with post-mortem findings or afterbirth imaging follow-up. CONCLUSIONS: Foetal MRI is an additional imaging modality in the diagnosis of cerebral ischemic-haemorrhagic lesions, and it is useful in providing further information on the extension of the parenchymal injury and associated abnormalities, thus improving delivery management.

The role of Doppler indices in predicting intra ventricular hemorrhage and perinatal mortality in fetal growth restriction.

OBJECTIVES: The aim of this study is to determine whether Doppler indices predict intra-ventricular hemorrhage and perinatal mortality in fetal growth restricted pregnancies (FGR). MATERIAL AND METHODS: In this cohort study, 43 FGR fetuses underwent multi-vessel Doppler ultrasounds weekly or twice weekly after admission. Blood gases of the umbilical cord were analyzed immediately after delivery. Ultrasonography of the neonatal brain was performed after birth. Intra ventricular hemorrhage (IVH) and perinatal mortality were studied as outcomes. RESULTS: The median gestational age at the diagnosis of fetal growth restriction was 31 weeks, and the median age at delivery was 33.4 weeks. Seven cases had IVH. The chance of IVH was about five times greater in cases of absent/reversed umbilical diastolic flow (AREDF). The predicting factors for IVH were gestational age at delivery, birth weight, and acidosis. Nine neonates died in the neonatal period. AREDF, the Resistance Index of middle cranial artery (MCA/RI) and umbilical artery (UA), and absent/reversed "a" waves in ductus venosus (DV) were the Doppler indices predicting perinatal mortality. The other prognostic factors for perinatal mortality were gestational age at diagnosis and delivery, final amniotic fluid, Apgar score, and acidosis. CONCLUSION: Doppler indices, such as AREDF, can be predictors of IVH or perinatal death, and an absent or reversed "a" wave in the ductus venosus and the hypoxic index can be significant predictors of death in fetuses with fetal growth restriction. However, other important factors for IVH were gestational age at delivery and birth weight. The most important factors predicting perinatal mortality were gestational age, birth weight, acidosis, low AF, and low Apgar score.

ßPix plays a dual role in cerebral vascular stability and angiogenesis, and interacts with integrin αvß8.

The growth of new blood vessels by angiogenesis and their stabilization by the recruitment of perivascular mural cells are thought to be two sequential, yet independent events. Here we identify molecular links between both processes through the ßPix and integrin α(v)ß(8) proteins. Bubblehead (bbh) mutants with a genetic mutation in ßPix show defective vascular stabilization. ßPix is a guanine nucleotide exchange factor and scaffold protein that binds many proteins including Git1, which bridges ßPix to integrins at focal adhesions. Here we show that the ability of ßPix to stabilize vessels requires Git1 binding residues. Knockdown of Git1 leads to a hemorrhage phenotype similar to loss of integrin α(v), integrin ß(8) or ßPix, suggesting that vascular stabilization through ßPix involves interactions with integrins. Furthermore, double loss of function of ßPix and integrin α(v) shows enhanced hemorrhage rates. Not only is vascular stability impaired in these embryos, but we also uncover a novel role of both ßPix and integrin α(v)ß(8) in cerebral angiogenesis. Downregulation of either ßPix or integrin α(v)ß(8) results in fewer and morphologically abnormal cerebral arteries penetrating the hindbrain. We show that this is coupled with a significant reduction in endothelial cell proliferation in bbh mutants or integrin α(v)ß(8) morphants. These data suggest that a complex involving ßPix, GIT1 and integrin α(v)ß(8) may regulate vascular stability, cerebral angiogenesis and endothelial cell proliferation in the developing embryo.

pak2a mutations cause cerebral hemorrhage in redhead zebrafish.

The zebrafish is a powerful model for studying vascular development, demonstrating remarkable conservation of this process with mammals. Here, we identify a zebrafish mutant, redhead (rhd(mi149)), that exhibits embryonic CNS hemorrhage with intact gross development of the vasculature and normal hemostatic function. We show that the rhd phenotype is caused by a hypomorphic mutation in p21-activated kinase 2a (pak2a). PAK2 is a kinase that acts downstream of the Rho-family GTPases CDC42 and RAC and has been implicated in angiogenesis, regulation of cytoskeletal structure, and endothelial cell migration and contractility among other functions. Correction of the Pak2a-deficient phenotype by Pak2a overexpression depends on kinase activity, implicating Pak2 signaling in the maintenance of vascular integrity. Rescue by an endothelial-specific transgene further suggests that the hemorrhage seen in Pak2a deficiency is the result of an autonomous endothelial cell defect. Reduced expression of another PAK2 ortholog, pak2b, in Pak2a-deficient embryos results in a more severe hemorrhagic phenotype, consistent with partially overlapping functions for these two orthologs. These data provide in vivo evidence for a critical function of Pak2 in vascular integrity and demonstrate a severe disease phenotype resulting from loss of Pak2 function.

Visual development in infants with prenatal post-haemorrhagic ventricular dilatation.

OBJECTIVE: The aim of this study was to assess visual function in 13 infants with evidence of prenatal post haemorrhagic ventricular dilatation. DESIGN: Infants were assessed at 5, 12 and 24 months using a battery of tests specifically designed to assess various aspects of visual function in infancy. Visual findings were correlated with several variables, including extent of the lesion and presence of epilepsy. RESULTS AND CONCLUSIONS: Abnormalities of visual function were frequent (over 60%) in our cohort at age 2 years, ranging from isolated abnormal ocular movements to severe abnormalities of all the aspects of visual function assessed. The most severe and persistent abnormalities of visual function were found in infants with grade IV intraventricular haemorrhage and shunted hydrocephalus who also had epilepsy in the first year.

Are routine cranial ultrasounds necessary in premature infants greater than 30 weeks gestation?

The purpose of this study was to validate the recommendation of the American Academy of Neurology and the Child Neurology Society that screening cranial ultrasonography be performed routinely on all infants of less than 30 weeks gestation at 7 to 14 days of age and again between 36 and 40 weeks postmenstrual age, and, by using this practice parameter, to determine the number of babies with a clinically significant abnormal screening cranial ultrasound (US) who would otherwise have been missed. A retrospective study of 486 infants of 30 to 33 weeks gestation born January 1, 1999 to June 30, 2004 was done. All had screening cranial ultrasounds. Grade III and/or grade IV intraventricular hemorrhage (IVH) occurred in 4 (0.8%) infants of 30 to 31 weeks gestation. Infants with significant IVH had either risk factors for brain injury or symptoms that would eventually warrant US during their hospitalization. Seven (1.4%) infants had periventricular leukomalacia (PVL). All infants with a final diagnosis of PVL had pre- and/or perinatal risk factors associated with PVL. There was a significant trend toward fewer abnormal cranial ultrasounds from 30 to 33 weeks gestation (p=0.04). Our study supports the recommendation by the American Academy of Neurology and the Child Neurology Society that screening US can be limited but suggests that the gestational age cut off should be 30 weeks or less.

Fetal germinal matrix and intraventricular hemorrhage.

Subependymal germinal matrix with intraventricular hemorrhage (GMIVH) is a common complication associated with delivery in preterm neonates but has rarely been observed in the fetus. Clinical and neuroradiological findings of 5 patients who were diagnosed as having fetal GMIVH with prenatal ultrasonographic examinations (US) and MRI, and postnatal MRI were reviewed retrospectively. During a seemingly uneventful pregnancy, fetal GMIVH occurred at approximately 30-33 weeks of gestation, with the absence of any known factor predisposing to fetal hemorrhage. Routine obstetric US revealed an intraventricular lesion in the enlarged ventricles. Prenatal MRI clearly demonstrated parenchymal change such as intracerebral hematoma adjacent to the subependymal and intraventricular hematoma, and periventricular leukomalacia as well as GMIVH. Although patients without parenchymal destruction (hemosiderin deposit alone) had a favorable neurodevelopmental outcome, encephalomalacia and periventricular leukomalacia contributed to long-term neurodevelopmental deficits. Evaluating parenchymal damage with prenatal MRI can therefore help to predict neurodevelopmental prognosis of the fetus with GMIVH.

Visual field defects in prematurely born patients with white matter damage of immaturity: a multiple-case study.

PURPOSE: White matter damage of immaturity may affect visual, motor and cognitive functions. This multiple-case study presents standardized perimetry results in six teenagers and young adults born prematurely with visual dysfunction due to white matter damage of immaturity of pre- or perinatal origin. METHODS: Six subjects, aged 13-25 years, born at a gestational age of 28-34 weeks, with white matter damage of immaturity documented by MRI, and optic disc appearances documented by fundus photography, were examined with manual and computerized quantitative perimetry. RESULTS: All subjects had subnormal visual field (VF) function, although the depth and extension of the VF defects differed between subjects. The inferior VF function was more deviant than the superior in all cases. The concordance between the VF defects detected with the different techniques was good, although the static computerized techniques revealed slightly more abnormality. CONCLUSION: White matter damage of immaturity may affect the VF. The lower VF is often more affected than the upper. The abnormalities can be demonstrated by both manual and computerized perimetry.

Contribution of fetal MR imaging in the evaluation of cerebral ischemic lesions.

BACKGROUND AND PURPOSE: Little is known about the different patterns of fetal cerebral ischemic lesions at MR imaging. Our purpose was to evaluate the contribution of MR imaging in the evaluation of such lesions by correlating the results with ultrasonography (US) and neurofetopathologic (NFP) findings. METHODS: We examined 28 fetuses (mean, 28 weeks' gestation) with cerebral ischemic lesions on NFP examination. MR findings were correlated with US and NFP results with regard to the depiction of gyration and parenchymal abnormalities. RESULTS: MR imaging added to US findings in 24 cases by revealing lesions (gyration abnormalities, parenchymal lesions). These results were either overlooked during US (n = 16) or more extensive than expected with US (n = 8). MR findings were always confirmed by NFP. NFP yielded additional findings for 14 lesions that were overlooked during MR imaging (n = 4) or that were more extensive than expected with MR imaging (n = 10). T1-, T2-, and T2*-weighted MR patterns of different lesions (cavitations, gliosis, softening of the white matter, laminar necrosis, calcified leukomalacia, old hemorrhage) were identified. CONCLUSION: MR imaging is a valuable tool in the evaluation of fetal brain ischemia. The results of this study emphasize the role of the different sequences (T1-, T2-, T2*-weighted) required to detect fetal cerebral ischemic lesions. MR imaging is more accurate in the detection of small focal lesions than in the evaluation of diffuse white matter abnormalities.

Infection-related perinatal brain injury: the pathogenic role of impaired fetal cardiovascular control.

There is a growing body of evidence from clinical and epidemiologic studies that in utero exposure to infection plays an important role in the genesis of fetal or neonatal injury leading to cerebral palsy and chronic lung disease. Thus, after chorioamnionitis the incidence of immature neonates with periventricular white matter damage and periventricular or intraventricular hemorrhage is significantly elevated. Recent clinical and experimental data support the hypothesis that a fetal inflammatory response links antenatal infection with brain white matter damage and subsequent motor handicap. A variety of studies support the view that cytokines released during intrauterine infection directly cause injury to the immature brain. In this review, we provide evidence that in utero exposure to bacterial infection can severely alter fetal cardiovascular function, resulting in dysregulation of cerebral blood flow and subsequent hypoxic-ischemic brain injury.

Optic disc morphology may reveal timing of insult in children with periventricular leucomalacia and/or periventricular haemorrhage.

AIMS: To evaluate the relation between optic disc morphology and timing of periventricular white matter damage, defined as either periventricular leucomalacia (PVL) or periventricular haemorrhage (PVH), as estimated by neuroradiology. METHODS: 35 children with periventricular white matter damage who had had neuroradiology performed and ocular fundus photographs taken had their photographs analysed by digital image analysis and compared with a control group of 100 healthy full term children. Timing of brain lesion was estimated by analysis of the brain lesion pattern on neuroradiological examinations (magnetic resonance imaging or computed tomography). RESULTS: Four of 35 children had a small optic disc area; these four children had a brain lesion estimated to have occurred before 28 weeks of gestation. Nine of 11 children with a large cup area had a PVL/PVH estimated to have occurred after 28 weeks of gestation. The children with PVL/PVH had a significantly larger cup area (median 0.75 mm(2)) than the control group (median 0.33 mm(2)) (p = 0.001) and a significantly smaller neuroretinal rim area (median 1.58 mm(2)) than the controls (median 2.07 mm(2)) (p = 0.001). CONCLUSION: In a child with PVL/PVH and abnormal optic disc morphology, the possibilities of timing of the lesion should be considered.

Comparison of perinatal outcome in fetuses with reverse or absent enddiastolic flow in the umbilical artery and/or fetal descending aorta.

OBJECTIVES: To examine the differences of perinatal outcome in fetuses with absent and reversed enddiastolic flow velocity waveforms of the umbilical artery or fetal descending aorta. DESIGN: In a retrospective study, 30 pregnant women with reversed enddiastolic flow in the umbilical artery or fetal aorta (group I) were compared with 30 cases of absent enddiastolic flow (group II). Patients were included in the groups according to the last Doppler finding before delivery. Perinatal and neonatal outcome was correlated with antenatal Doppler flow findings. RESULTS: The mean gestational age at birth was 31 weeks in both groups. Fetuses with reverse flow showed higher perinatal (27% and 7% respectively) and overall mortality (53.3% and 10% respectively) compared to the absent enddiastolic flow group (p < 0.05). All the intrauterine fetal deaths occurred in the reversed flow group (n = 12). The rates of intrauterine growth retardation, oligohydramnios and hypocalcemia were different between the groups (p < 0.05). The cesarean section rate, perinatal and neonatal complications including the incidence of acidosis, the number of cases admitted to neonatal intensive care unit and mean treatment time were not different between the groups. A tendency to higher incidence of neonatal cerebral hemorrhage in reversed flow cases (28%) compared to absent enddiastolic flow cases (17%) was observed, but this was not statistically significant. CONCLUSIONS: The present study suggests that reversed flow should be seen as a particular clinical entity with higher incidences of perinatal and overall mortality, and severe intrauterine growth retardation (< 5. perc) compared to the absent enddiastolic flow group. The optimal timing of delivery in pregnancies complicated by highly pathological Doppler flow findings is only to be resolved in well-designed randomized, multicenter clinical trials.

Widening spectrum of congenital hemiplegia: Periventricular venous infarction in term neonates.

MRI in five term children with congenital hemiplegia without clinically apparent prenatal or perinatal difficulties showed a focal or porencephalic enlargement of the lateral ventricle and periventricular T2 prolongation, which were identical to findings of periventricular venous infarction seen in preterm children. Some cases of congenital hemiplegia in term neonates may be due to clinically silent periventricular venous infarction that occurred in utero.

[Fetal germinal matrix and intraventricular hemorrhage associated with periventricular leukomalacia].

Subependymal germinal matrix hemorrhage with intraventricular hemorrhage(SEIVH) is a common complication associated with delivery in preterm neonates but has rarely been observed in the fetus. We report a fetus with SEIVH, hydrocephalus and periventricular leukomalacia(PVL). Although this fetus had uneventful prenatal periods, transabdominal ultrasound examination(US) at 33 weeks of pregnancy revealed SEIVH and hydrocephalus, and MRI at 36 weeks did associated PVL. While no events reported that could explain the onset of SEIVH, PVL was considered to be the results of anoxic events associated with SEIVH. In addition to US, information provided by fetal MRI, especially T 2-weighted image, permits a better understanding of the pathophysiology of fetal SEIVH with PVL.