Neonatal Phenotype Research Articles

Diagnostic accuracy of cell-free DNA in maternal blood in detecting chromosomal anomalies in twin pregnancies: systematic review and meta-analysis.

To report the diagnostic accuracy of cell-free DNA (cfDNA) in maternal blood in detecting chromosomal anomalies in twin pregnancies. Medline, Embase and Cochrane databases were searched. The inclusion criteria were twin pregnancies undergoing cfDNA screening for Trisomies 13, 18, 21, monosomy X0 and other sex chromosomal anomalies (SCA). The index test was represented by a positive results of cfDNA test. The reference standard was represented by the karyotype results (obtained either pre or postnatally) or, in case of negative cfDNA result, by a normal neonatal phenotype. The quality of the studies was assessed using the revised tool for the quality assessment of diagnostic accuracy studies (QUADAS-2). Summary estimates of sensitivity, specificity, positive and negative likelihood ratios (LR+ and LR-) and diagnostic odds ratio (DOR), with the corresponding 95% Confidence Intervals (95% CI), were computed using the bivariate random-effects model. Thirty-five studies were included. cfDNA had an overall high accuracy in detecting Trisomy 21 in twin pregnancies with a sensitivity of 98.8% (95% CI 96.5-100), a specificity of 100% (95% CI 99.9-100). Sensitivity and specificity were of 94.9% (95% CI 75.6-99.1) and 100 (95% CI 99.9-100) for Trisomy 18, and 84.6% (95% C% 54.6-98.1) and 100% (95% CI 99.9-100) for Trisomy 13 . We could not compute the diagnostic accuracy of cfDNA in detecting monosomy X0 in twins, while cfDNA had a sensitivity of 100% (95% CI 71.5-100) and a specificity of 99.8% (95% CI 99.7-99.9) in detecting other SCA (11 cases). The accuracy of cfDNA in detecting Trisomy 21, 18 and 13 was similar in dichorionic and monochorionic twin pregnancies. cfDNA has a high diagnostic accuracy in detecting Trisomy 18 and 21 in twin pregnancies, irrespective of chorionicity. Accuracy in the detection of Trisomy 13 and SCA was limited by the small number of affected cases and the difficulties in the confirmation of false negative cases in case of SCA and requires confirmation in larger studies. This article is protected by copyright. All rights reserved.

Prenatal and neonatal phenotype of Larsen of La Réunion Island syndrome (B4GALT7-linkeropathy)

Larsen of La Réunion Island syndrome (LRS) is an autosomal recessive condition associated with multiple large joint dislocations, clubfeet, severe dwarfism, and distinctive facial features. LRS is caused by a recurrent homozygous variant in B4GALT7 gene with a founder effect in La Réunion population. Proteoglycans (PG) that are a major component of the extracellular matrix, are composed of a core protein connected to a glycosaminoglycans side chain via a tetrasaccharide linker region. B4GALT7 encodes galactosyltransferase I, one of the enzymes involved in the biosynthesis of the linker region. Conditions caused by pathogenic biallelic variants in genes implicated in the synthesis of the tetrasaccharide linker of PG are known as linkeropathies.Prenatal features are rarely described in this group of chondrodysplasias. We present a series of 12 unpublished patients having LRS and describe the perinatal phenotype. All the patients had a prenatal growth restriction with brevity of limbs. The other features revealed by ultrasounds were increased nuchal translucency at 10–12 weeks of gestation (50 %), feet abnormalities (clubfeet or metatarsus varus) (25 %), dislocation affecting at least one large joint (elbow, knee, wrist) (25 %). Bilateral bowing of femora was noted for two fetuses. Fibular hypertrophy was noted for one fetus. Prenatal helical computed tomography (CT) performed in three pregnancies showed additional data such as bowing of the forearm bones, proximal radio-ulnar synostosis, or dislocation of large joints. Prenatal sonographic and helical CT findings led to the prenatal diagnosis of LRS in four patients. We confirm that the neonatal clinical picture of LRS has an important overlap with that reported in patients with B4GALT7 deficiency outside La Réunion Island and other linkeropathies. The core of the phenotypic spectrum combines low birth height, micromelia, hypermobility, dislocation of at least one large joint, facial features with prominent eyes, microstomia, depressed nasal bridge, and midface hypoplasia. Other clinical features include clubfeet (33%), bifid thumb in one patient, and cardiac abnormalities in two patients. Radiological findings include radio-ulnar synostosis (75%), metaphyseal flaring, precocious carpal ossification, and a Swedish key appearance of the proximal femora. Finally, we also report radiological features rarely described in B4GALT7-linkeropathies, including bowing of the femora and fibular hypertrophy. Our results confirm the phenotypic continuum of LRS within linkeropathies with some additional findings, including a high frequency of clubfeet usually described in B3GALT6-linkeropathies, the presence of congenital heart diseases usually described in B3GAT3-linkeropathies, and a high frequency of metaphyseal flaring usually reported in B3GALT6 or XITLT1-linkeropathies.This is the first study that describes the perinatal phenotype in a cohort of patients with LRS. This study can help improve the prenatal diagnosis of the linkeropathies and add this group of conditions to the differential diagnosis of chondrodysplasias with multiple dislocations.In view of the founder effect for LRS in La Réunion Island, this disease should be suspected in fetuses with growth restriction and micromelia. Thus in case of LOH which include B4GALT7 identified in SNP-array, we recommend performing a targeted Sanger sequencing for the recurrent mutation c.808C > T; p. (Arg270Cys).

Determinants Of Postdate Pregnancies and Neonatal Phenotype in a Rural Low-Income, High-Altitude Population

Determinants Of Postdate Pregnancies and Neonatal Phenotype in a Rural Low-Income, High-Altitude Population

ATS core curriculum 2023. Pediatric pulmonary medicine: Respiratory disorders in infants.

The American Thoracic Society Core Curriculum updates clinicians annually in pediatric pulmonary disease. This is a summary of the Pediatric Pulmonary Medicine Core Curriculum presented at the 2023 American Thoracic Society International Conference. The respiratory disorders of infancy discussed in this year's review include: the care of the patient with bronchopulmonary dysplasia in the neonatal intensive care unit, clinical phenotypes and comorbidities; diffuse lung disease; pulmonary hypertension; central and obstructive sleep apnea. The care of infants with respiratory disorders often poses significant challenges to the general pediatric pulmonologist, sleep clinician, and neonatologist. This review aims to highlight the most clinically relevant aspects of the evaluation, management, and outcomes of infants with these key respiratory disorders, while emphasizing the importance of multidisciplinary care. Furthermore, this document summarizes essential aspects of genetic testing, novel imaging and treatment modalities, and includes multiple resources for clinical practice.

Neonatal Ultrasound and Radiographic Markers of Hip Dysplasia in Young Adults.

To examine radiologic outcomes at skeletal maturity of sonographically normal, immature, mildly, and severely dysplastic newborn hips. During 1988 to 1990, 11 925 newborns were enrolled in a randomized controlled trial examining screening strategies for developmental hip dysplasia. In total, 4469 were invited to clinical and radiologic follow-up 18 years later, of which 1735 had received neonatal ultrasound. Radiographic markers for dysplasia in left adult hips included the center-edge (CE) angle. At follow-up, 984 of 1735 (56.7%) with newborn ultrasound met, of which 966 (614 females) had valid radiographs and were thus included. For females, 34 (10.2%) and 1 (0.3%) of the 332 sonographically normal left neonatal hips were judged borderline (20°≤ CE <25°) or dysplastic (CE <20°) at skeletal maturity respectively. Corresponding numbers were 36 (19.7%) and 3 (1.6%) of the 183 immature, 12 (15.6%) and 2 (2.6%) of the 77 mildly dysplastic, and 3 (13.6%) and 3 (13.6%) of the 22 severely dysplastic neonatal left hips (P ≤ .001). In males, no associations were found. In females, adult joint hypermobility was associated with sonographic neonatal hip instability (P = .046), as well as with adult acetabular dysplasia (P = .024). Significant associations between neonatal hip phenotypes and adult dysplasia were revealed in females. This indicates the possibility of different mechanisms affecting the course of developmental dysplasia of the hip for females and males, prompting consideration of prolonged clinical and radiologic follow-up for females with dysplastic neonatal hips. Results in males are limited by low numbers of dysplastic hips. The significance of joint hypermobility warrants further investigation.

Enteric glial cell network function is required for epithelial barrier restitution following intestinal ischemic injury in the early postnatal period.

Ischemic damage to the intestinal epithelial barrier, such as in necrotizing enterocolitis or small intestinal volvulus, is associated with higher mortality rates in younger patients. We have recently reported a powerful pig model to investigate these age-dependent outcomes in which mucosal barrier restitution is strikingly absent in neonates but can be rescued by direct application of homogenized mucosa from older, juvenile pigs by a yet-undefined mechanism. Within the mucosa, a postnatally developing network of enteric glial cells (EGCs) is gaining recognition as a key regulator of the mucosal barrier. Therefore, we hypothesized that the developing EGC network may play an important role in coordinating intestinal barrier repair in neonates. Neonatal and juvenile jejunal mucosa recovering from surgically induced intestinal ischemia was visualized by scanning electron microscopy and the transcriptomic phenotypes were assessed by bulk RNA sequencing. EGC network density and glial activity were examined by Gene Set Enrichment Analysis, three-dimensional (3-D) volume imaging, and Western blot and its function in regulating epithelial restitution was assessed ex vivo in Ussing chamber using the glia-specific inhibitor fluoroacetate (FA), and in vitro by coculture assay. Here we refine and elaborate our translational model, confirming a neonatal phenotype characterized by a complete lack of coordinated reparative signaling in the mucosal microenvironment. Furthermore, we report important evidence that the subepithelial EGC network changes significantly over the early postnatal period and demonstrate that the proximity of a specific functional population of EGC to wounded intestinal epithelium contributes to intestinal barrier restitution following ischemic injury.NEW & NOTEWORTHY This study refines a powerful translational pig model, defining an age-dependent relationship between enteric glia and the intestinal epithelium during intestinal ischemic injury and confirming an important role for enteric glial cell (EGC) activity in driving mucosal barrier restitution. This study suggests that targeting the enteric glial network could lead to novel interventions to improve recovery from intestinal injury in neonatal patients.

LRP4 site-specific variants in the third β-propeller domain causes congenital myasthenic syndrome type 17

LRP4 is expressed in many organs. It mediates SOST-dependent inhibition of bone formation and acts as an inhibitor of WNT signaling. It is also a postsynaptic end plate cell surface receptor at the neuromuscular junction and is central to its development, maintenance, and function. Pathogenic variants of LRP4 that specifically affect the canonical WNT signaling pathway are known to be associated with Cenani-Lenz syndactyly syndrome or the overlapping condition sclerosteosis. However, site-specific pathogenic variants of LRP4 have been associated with the congenital myasthenic syndrome (CMS) type 17 with no abnormal bone phenotype. Only two studies reported biallelic variants of LRP4 associated with CMS17 that presented during childhood. All three reported variants (NM_002334.4: p.Glu1233Ala, p.Glu1233Lys, or p.Arg1277His) are located within the 3′-edge of the third β-propeller domain of LRP4. We report on a patient with a biallelic variant of the LRP4 gene presenting with a severe and neonatal lethal phenotype; we also provide a literature review of the previously reported patients. A female neonate, born to healthy consanguineous parents, presented with severe hypotonia, congenital diaphragmatic hernia, pulmonary hypertension, and progressive hypoxemia. Two of her siblings presented with a similar condition in the past, and all three died shortly after birth. Clinical exome sequencing revealed homozygosity for the pathogenic variant NM_002334.4:c.3698A > C (p.[Glu1233Ala]).

ClinVar and HGMD genomic variant classification accuracy has improved over time, as measured by implied disease burden

BackgroundCurated databases of genetic variants assist clinicians and researchers in interpreting genetic variation. Yet, these databases contain some misclassified variants. It is unclear whether variant misclassification is abating as these databases rapidly grow and implement new guidelines.MethodsUsing archives of ClinVar and HGMD, we investigated how variant misclassification has changed over 6 years, across different ancestry groups. We considered inborn errors of metabolism (IEMs) screened in newborns as a model system because these disorders are often highly penetrant with neonatal phenotypes. We used samples from the 1000 Genomes Project (1KGP) to identify individuals with genotypes that were classified by the databases as pathogenic. Due to the rarity of IEMs, nearly all such classified pathogenic genotypes indicate likely variant misclassification in ClinVar or HGMD.ResultsWhile the false-positive rates of both ClinVar and HGMD have improved over time, HGMD variants currently imply two orders of magnitude more affected individuals in 1KGP than ClinVar variants. We observed that African ancestry individuals have a significantly increased chance of being incorrectly indicated to be affected by a screened IEM when HGMD variants are used. However, this bias affecting genomes of African ancestry was no longer significant once common variants were removed in accordance with recent variant classification guidelines. We discovered that ClinVar variants classified as Pathogenic or Likely Pathogenic are reclassified sixfold more often than DM or DM? variants in HGMD, which has likely resulted in ClinVar’s lower false-positive rate.ConclusionsConsidering misclassified variants that have since been reclassified reveals our increasing understanding of rare genetic variation. We found that variant classification guidelines and allele frequency databases comprising genetically diverse samples are important factors in reclassification. We also discovered that ClinVar variants common in European and South Asian individuals were more likely to be reclassified to a lower confidence category, perhaps due to an increased chance of these variants being classified by multiple submitters. We discuss features for variant classification databases that would support their continued improvement.

Maternal pre-conceptional glyphosate exposure impacts the offspring hepatic and ovarian proteome.

Glyphosate (GLY) is an herbicide used for rural and urban weed control. Urinary GLY in women is associated with shortened gestational length yet effects of GLY on offspring due to maternal exposure are unclear. This study tested the hypothesis that maternal chronic pre-conceptional GLY exposure would cause phenotypic and molecular changes in F1 offspring. Female C57BL/6 mice (7-week-old; n = 40) received saline vehicle control (CT; n = 20) or GLY (2 mg/kg; n = 20) daily per os for 10 weeks. At dosing completion, females were housed with unexposed males and divided into Cohort 1 who were euthanized at gestation day 14 (n = 10 per treatment) and Cohort 2 who completed gestation (n = 10 per treatment). F1 female ovarian and liver samples underwent LC-MS/MS and bioinformatic analysis. Maternal exposure did not affect litter (P > .05) sex ratio, or embryonic or neonatal gross phenotypes. In Cohort 2 offspring, no treatment effect on (P > .05) offspring anogenital distance, puberty onset, or ovarian follicular composition was noted. Body weight was increased (P < .05) in male GLY-exposed compared with CT dam offspring. F1 females from GLY-exposed dams had altered (P < .05) abundance of 54 ovarian and 110 hepatic proteins. Pathways altered in the ovary (false discovery rate [FDR] ≤ 0.07) included thermogenesis and phosphatidylinositol-3 kinase-AKT signaling and in liver (FDR ≤ 0.08) included metabolic, glutathione metabolism, oxidative phosphorylation, non-alcoholic fatty liver disease, and thermogenesis. Thus, pre-conceptional GLY exposure affected offspring phenotypic and molecular profiles potentially impacting reproductive health.

Lipid nanoparticle-encapsulated mRNA therapy corrects serum total bilirubin level in Crigler-Najjar syndrome mouse model

Crigler-Najjar syndrome is a rare disorder of bilirubin metabolism caused by uridine diphosphate glucuronosyl transferase 1A1 (UGT1A1) mutations characterized by hyperbilirubinemia and jaundice. No cure currently exists; treatment options are limited to phototherapy, whose effectiveness diminishes over time, and liver transplantation. Here, we evaluated the therapeutic potential of systemically administered, lipid nanoparticle-encapsulated human UGT1A1 (hUGT1A1) mRNA therapy in a Crigler-Najjar mouse model. Ugt1 knockout mice were rescued from lethal post-natal hyperbilirubinemia by phototherapy. These adult Ugt1 knockout mice were then administered a single lipid nanoparticle-encapsulated hUGT1A1 mRNA dose. Within 24 h, serum total bilirubin levels decreased from 15 mg/dL (256μmol/L) to <0.5mg/dL (9μmol/L), i.e., slightly above wild-type levels. This reduction was sustained for 2weeks before bilirubin levels rose and returned to pre-treatment levels by day 42 post-administration. Sustained reductions in total bilirubin levels were achieved by repeated administration of the mRNA product in a frequency-dependent manner. We were also able to rescue the neonatal lethality phenotype seen in Ugt1 knockout mice with a single lipid nanoparticle dose, which suggests that this may be a treatment modality appropriate for metabolic crisis situations. Therefore, lipid nanoparticle-encapsulated hUGT1A1 mRNA may represent a potential treatment for Crigler-Najjar syndrome.

Clinical and Neurophysiologic Phenotypes in Neonates With BRAT1 Encephalopathy.

BRAT1 encephalopathy is an ultra-rare autosomal recessive neonatal encephalopathy. We delineate the neonatal electroclinical phenotype at presentation and provide insights for early diagnosis. Through a multinational collaborative, we studied a cohort of neonates with encephalopathy associated with biallelic pathogenic variants in BRAT1 for whom detailed clinical, neurophysiologic, and neuroimaging information was available from the onset of symptoms. Neuropathologic changes were also analyzed. We included 19 neonates. Most neonates were born at term (16/19) from nonconsanguineous parents. 15/19 (79%) were admitted soon after birth to a neonatal intensive care unit, exhibiting multifocal myoclonus, both spontaneous and exacerbated by stimulation. 7/19 (37%) had arthrogryposis at birth, and all except 1 progressively developed hypertonia in the first week of life. Multifocal myoclonus, which was present in all but 1 infant, was the most prominent manifestation and did not show any EEG correlate in 16/19 (84%). Video-EEG at onset was unremarkable in 14/19 (74%) infants, and 6 (33%) had initially been misdiagnosed with hyperekplexia. Multifocal seizures were observed at a median age of 14 days (range: 1-29). During the first months of life, all infants developed progressive encephalopathy, acquired microcephaly, prolonged bouts of apnea, and bradycardia, leading to cardiac arrest and death at a median age of 3.5 months (range: 20 days to 30 months). Only 7 infants (37%) received a definite diagnosis before death, at a median age of 34 days (range: 25-126), and almost two-thirds (12/19, 63%) were diagnosed 8 days to 12 years postmortem (median: 6.5 years). Neuropathology examination, performed in 3 patients, revealed severely delayed myelination and diffuse astrogliosis, sparing the upper cortical layers. BRAT1 encephalopathy is a neonatal-onset, rapidly progressive neurologic disorder. Neonates are often misdiagnosed as having hyperekplexia, and many die undiagnosed. The key phenotypic features are multifocal myoclonus, an organized EEG, progressive, persistent, and diffuse hypertonia, and an evolution into refractory multifocal seizures, prolonged bouts of apnea, bradycardia, and early death. Early recognition of BRAT1 encephalopathy allows for prompt workup, appropriate management, and genetic counseling.

Intrauterine growth restriction, prematurity, and low birth weight: risk phenotypes of neonatal death, Rio de Janeiro State, Brazil.

Intrauterine growth restriction and prematurity determine low birth weight. The combination of the three conditions results in different neonatal phenotypes that interfere with child survival. Neonatal prevalence, survival and mortality were estimated according to neonatal phenotypes in the cohort of live births in 2021 in the state of Rio de Janeiro, Brazil. In this study, live births of multiple pregnancies, with congenital anomalies and inconsistencies in the information of weight and gestational age were excluded. The Intergrowth curve was used to classify weight adequacy. Mortality (< 24 hours, 1-6 and 7-27 days) and survival (Kaplan-Meier) were estimated. In total, 6.8%, 5.5%, and 9.5% of the 174,399 live births were low birth weight, small for gestational age (SGA), and premature, respectively. Considering low birth weight live births, 39.7% were SGA and 70% were premature. The neonatal phenotypes were heterogeneous according to maternal, delivery, pregnancy, and newborn characteristics. The mortality rate per 1,000 live births was high for low birth weight premature newborns, both SGA (78.1) and AGA (adequate for gestational age: 61.1), at all specific ages. Reductions in the survival rate were observed when comparing non-low birth weight and AGA term live births. The estimated prevalence values were lower than those of other studies, partly due to the exclusion criteria adopted. The neonatal phenotypes identified children who were more vulnerable and at higher risk of death. Prematurity contributed more to mortality than SGA, and its prevention is necessary to reduce neonatal mortality in the state of Rio de Janeiro.

Restrição do crescimento intrauterino, prematuridade e baixo peso ao nascer: fenótipos de risco de morte neonatal, Estado do Rio de Janeiro, Brasil

Abstract: Intrauterine growth restriction and prematurity determine low birth weight. The combination of the three conditions results in different neonatal phenotypes that interfere with child survival. Neonatal prevalence, survival and mortality were estimated according to neonatal phenotypes in the cohort of live births in 2021 in the state of Rio de Janeiro, Brazil. In this study, live births of multiple pregnancies, with congenital anomalies and inconsistencies in the information of weight and gestational age were excluded. The Intergrowth curve was used to classify weight adequacy. Mortality (&lt; 24 hours, 1-6 and 7-27 days) and survival (Kaplan-Meier) were estimated. In total, 6.8%, 5.5%, and 9.5% of the 174,399 live births were low birth weight, small for gestational age (SGA), and premature, respectively. Considering low birth weight live births, 39.7% were SGA and 70% were premature. The neonatal phenotypes were heterogeneous according to maternal, delivery, pregnancy, and newborn characteristics. The mortality rate per 1,000 live births was high for low birth weight premature newborns, both SGA (78.1) and AGA (adequate for gestational age: 61.1), at all specific ages. Reductions in the survival rate were observed when comparing non-low birth weight and AGA term live births. The estimated prevalence values were lower than those of other studies, partly due to the exclusion criteria adopted. The neonatal phenotypes identified children who were more vulnerable and at higher risk of death. Prematurity contributed more to mortality than SGA, and its prevention is necessary to reduce neonatal mortality in the state of Rio de Janeiro.

Nanoengineering of gold nanoribbon-embedded isogenic stem cell-derived cardiac organoids.

Cardiac tissue engineering is an emerging field providing tools to treat and study cardiovascular diseases (CVDs). In the past years, the integration of stem cell technologies with micro- and nanoengineering techniques has enabled the creation of novel engineered cardiac tissues (ECTs) with potential applications in disease modeling, drug screening, and regenerative medicine. However, a major unaddressed limitation of stem cell-derived ECTs is their immature state, resembling a neonatal phenotype and genotype. The modulation of the cellular microenvironment within the ECTs has been proposed as an efficient mechanism to promote cellular maturation and improve features such as cellular coupling and synchronization. The integration of biological and nanoscale cues in the ECTs could serve as a tool for the modification and control of the engineered tissue microenvironment. Here we present a proof-of-concept study for the integration of biofunctionalized gold nanoribbons (AuNRs) with hiPSC-derived isogenic cardiac organoids to enhance tissue function and maturation. We first present extensive characterization of the synthesized AuNRs, their PEGylation and cytotoxicity evaluation. We then evaluated the functional contractility and transcriptomic profile of cardiac organoids fabricated with hiPSC-derived cardiomyocytes (mono-culture) as well as with hiPSC-derived cardiomyocytes and cardiac fibroblasts (co-culture). We demonstrated that PEGylated AuNRs are biocompatible and do not induce cell death in hiPSC-derived cardiac cells and organoids. We also found an improved transcriptomic profile of the co-cultured organoids indicating maturation of the hiPSC-derived cardiomyocytes in the presence of cardiac fibroblasts. Overall, we present for the first time the integration of AuNRs into cardiac organoids, showing promising results for improved tissue function.

2130. Neonatal Immune Phenotypes and Neurodevelopmental Outcomes in Infants with Congenital Cytomegalovirus Infection (cCMV)

Abstract Background Infants with congenital cytomegalovirus infection (cCMV) are at risk for neurodevelopmental impairment (NDI). Antiviral therapy has been shown to improve neurodevelopmental outcomes but is not recommended for all infected infants. There are currently no predictive markers for NDI in infants with cCMV. Our objective was to compare neonatal T cell differentiation and memory phenotypes in CMV-infected infants with and without subsequent NDI. Methods Blood samples were collected from infants with cCMV and age-matched healthy controls. Peripheral blood mononuclear cells were analyzed by flow cytometry for CD4 and CD8 T cells expressing CD28, CD57, PD, CD45RA/RO, and CCR7. Demographic and clinical data were collected. NDI was defined as Bayley III/IV testing below the average range in at least one domain in infants for whom this developmental testing was available or based on diagnosis by infectious disease physician or primary care provider. Outcomes for infants with follow-up at least 6 months of age were included. Infants with isolated speech delay associated with hearing loss were not considered to have NDI. Results Samples were analyzed from 18 infants (Table 1) at time of diagnosis (≤ 60 days of age) and 5 uninfected age-matched controls. The frequencies of CD8+ T cells expressing CD28low (differentiation), CD57+ (terminal differentiation/senescence), PD1hi (inhibitory or exhausted phenotype) and CD45RO± (memory) phenotypes were higher for the cCMV group without NDI compared to that with NDI (Figure 1). The cCMV group without NDI had lower proportions of naïve (CCR7+/CD45RA+) effector memory, TEM (CCR7-/CD45RA-), and effector memory RA, TEMRA (CCR7-/CD45RA+) CD8+ T cells than those with NDI (Figure 2). There was no difference in memory distribution or surface marker expression of CD4+ T cells. Table 1 Demographic and clinical characteristics of the infants with congenital cytomegalovirus infection (cCMV) with and without neurodevelopmental impairment (NI) and age-matched controls. Continuous variables are compared using the Mann Whitney U test and categorical variables with the Fischer’s Exact test. There were no significant differences between infants with and without NI. Figure 1.CD8+ T cell phenotypes in cCMV groups with and without Neurodevelopmental Impairment (NDI) Frequencies of CD8+ T cells lacking expression of CD28 (A), or expressing CD57 (B), PD-1 (C), or CD45RO (D) are shown at age ≤ 60 days. Infants with congenital CMV (cCMV) and normal neurodevelopmental outcome are shown in blue, infants with neurodevelopmental impairment are shown in red, and uninfected age-matched controls are shown in black. Data are shown as medians [interquartile range]. Groups were compared using the Mann Whitney U Test. Infants with no NDI had significantly higher frequencies of CD28- (p = 0.002), CD57+ (p = 0.001), PD-1+ (p = 0.01) and CD45RO+ (p = 0.01) CD8 T cells. * p ≤ 0.05; ** p ≤ 0.01. Figure 2.T cell memory subset distributions among cCMV groups and uninfected controls Proportions of CD4+ (A) and CD8+ (B) naïve (CCR7+/CD45RA+), central memory, TCM (CCR7+/CD45RA-), effector memory, TEM (CCR7-, CD45RA-), and effector memory RA, TEMRA (CCR7-/CD45RA+) T cells. Infants with congenital CMV (cCMV) and normal neurodevelopmental outcome are shown in blue, infants with neurodevelopmental impairment (NI) are shown in red while uninfected age-matched controls are shown in black and gray. Comparisons between T cell groups were made using the Mann Whitney U test. Infants with cCMV without NI had significantly fewer naïve (p = 0.0001), greater TEM (p = 0.0001), and TEMRA (p = 0.005) CD8+ T cells than those with NI. The distributions of CD4+ T cells were not significantly different. Conclusion In this small cohort of infants infected with CMV, these data suggest that a more differentiated memory CD8+ T cell phenotype in the neonatal period may correlate with normal neurodevelopmental outcomes. Disclosures Alexandra K. Medoro, MD, Merck: Grant/Research Support.

Endothelial dysfunction in preterm infants: The hidden legacy of uteroplacental pathologies.

Millions of infants are born prematurely every year worldwide. Prematurity, particularly at lower gestational ages, is associated with high mortality and morbidity and is a significant global health burden. Pregnancy complications and preterm birth syndrome strongly impact neonatal clinical phenotypes and outcomes. The vascular endothelium is a pivotal regulator of fetal growth and development. In recent years, the key role of uteroplacental pathologies impairing endothelial homeostasis is emerging. Conditions leading to very and extremely preterm birth can be classified into two main pathophysiological patterns or endotypes: infection/inflammation and dysfunctional placentation. The first is frequently related to chorioamnionitis, whereas the second is commonly associated with hypertensive disorders of pregnancy and fetal growth restriction. The nature, timing, and extent of prenatal noxa may alter fetal and neonatal endothelial phenotype and functions. Changes in the luminal surface, oxidative stress, growth factors imbalance, and dysregulation of permeability and vascular tone are the leading causes of endothelial dysfunction in preterm infants. However, the available evidence regarding endothelial physiology and damage is limited in neonates compared to adults. Herein, we discuss the current knowledge on endothelial dysfunction in the infectious/inflammatory and dysfunctional placentation endotypes of prematurity, summarizing their molecular features, available biomarkers, and clinical impact. Furthermore, knowledge gaps, shadows, and future research perspectives are highlighted.

Genetic and environmental factors influencing neonatal resting-state functional connectivity.

Functional magnetic resonance imaging has been used to identify complex brain networks by examining the correlation of blood-oxygen-level-dependent signals between brain regions during the resting state. Many of the brain networks identified in adults are detectable at birth, but genetic and environmental influences governing connectivity within and between these networks in early infancy have yet to be explored. We investigated genetic influences on neonatal resting-state connectivity phenotypes by generating intraclass correlations and performing mixed effects modeling to estimate narrow-sense heritability on measures of within network and between-network connectivity in a large cohort of neonate twins. We also used backwards elimination regression and mixed linear modeling to identify specific demographic and medical history variables influencing within and between network connectivity in a large cohort of typically developing twins and singletons. Of the 36 connectivity phenotypes examined, only 6 showed narrow-sense heritability estimates greater than 0.10, with none being statistically significant. Demographic and obstetric history variables contributed to between- and within-network connectivity. Our results suggest that in early infancy, genetic factors minimally influence brain connectivity. However, specific demographic and medical history variables, such as gestational age at birth and maternal psychiatric history, may influence resting-state connectivity measures.

138 Age-Dependent Intestinal Barrier Repair in Suckling Pigs: A Comparative Model to Improve Neonatal Gastrointestinal Health Across Species

Abstract As in porcine epidemic diarrhea virus, strangulating equine colic or necrotizing enterocolitis in human infants, intestinal diseases involving ischemic injury cause mucosal barrier damage and are associated with poorer survival in neonates. The cause of age-dependent outcomes in afflicted individuals has not been fully explained and therefore novel preventatives and treatments are lacking. While traditional rodent models have not demonstrated age-dependent differences in intestinal recovery, our translational pig model is the first to demonstrate an age-dependent intestinal barrier repair defect. We have shown that, while weaned pigs recover rapidly after ischemic intestinal injury, barrier repair is markedly impaired in suckling pigs, due to complete failure of epithelial restitution. Importantly, we found that the restitution defect in suckling pigs can be rescued by the direct application of homogenized mucosa from ischemia-injured small intestine from weaned pigs. Identifying reasons for this age-dependent defect in restitution and the components of the more mature pig mucosal tissues responsible for rescue will inform novel treatment interventions for neonates suffering with intestinal injury. Our lab has associated this age-dependent defect in barrier repair with an underdeveloped enteric glial cell (EGC) network, a postnatally developing component of the enteric nervous system known to regulate the intestinal barrier. We have found sub-epithelial EGC are reduced in neonates, neonatal epithelium in co-culture with EGC restitute more efficiently in vitro, and EGC inhibition ex vivo blocks restitution in juveniles recreating the neonatal phenotype. Further, as this EGC network is known to mature postnatally in response to the microbial colonization, we have found postnatal microbiota modulation with dietary prebiotic fiber supplementation exerts important effects on EGC network development and activity, and on EGC-epithelial pro-restitution crosstalk in vitro. Ongoing work to understand the roles of diet, microbiota, and the enteric nervous system on postnatal development of epithelial barrier repair can inform novel preventatives and interventions to improve intestinal health in vulnerable neonates.

Gain-of-Function Dynamin-2 Mutations Linked to Centronuclear Myopathy Impair Ca2+-Induced Exocytosis in Human Myoblasts.

Gain-of-function mutations of dynamin-2, a mechano-GTPase that remodels membrane and actin filaments, cause centronuclear myopathy (CNM), a congenital disease that mainly affects skeletal muscle tissue. Among these mutations, the variants p.A618T and p.S619L lead to a gain of function and cause a severe neonatal phenotype. By using total internal reflection fluorescence microscopy (TIRFM) in immortalized human myoblasts expressing the pH-sensitive fluorescent protein (pHluorin) fused to the insulin-responsive aminopeptidase IRAP as a reporter of the GLUT4 vesicle trafficking, we measured single pHluorin signals to investigate how p.A618T and p.S619L mutations influence exocytosis. We show here that both dynamin-2 mutations significantly reduced the number and durations of pHluorin signals induced by 10 μM ionomycin, indicating that in addition to impairing exocytosis, they also affect the fusion pore dynamics. These mutations also disrupt the formation of actin filaments, a process that reportedly favors exocytosis. This altered exocytosis might importantly disturb the plasmalemma expression of functional proteins such as the glucose transporter GLUT4 in skeletal muscle cells, impacting the physiology of the skeletal muscle tissue and contributing to the CNM disease.

Maternal immune activation alters fetal and neonatal microglia phenotype and disrupts neurogenesis in mice.

Activation of microglia, increase in cortical neuron density, and reduction in GABAergic interneurons are some of the key findings in postmortem autism spectrum disorders (ASD) subjects. The aim of this study was to investigate how maternal immune activation (MIA) programs microglial phenotypes and abnormal neurogenesis in offspring mice. MIA was induced by injection of lipopolysaccharide (LPS, i.p.) to pregnant mice at embryonic (E) day 12.5. Microglial phenotypes and neurogenesis were investigated between E15.5 to postnatal (P) day 21 by immunohistochemistry, flow cytometry, and cytokine array. MIA led to a robust increase in fetal and neonatal microglia in neurogenic regions. Homeostatic E15.5 and P4 microglia are heterogeneous, consisting of M1 (CD86+/CD206-) and mixed M1/M2 (CD86+/CD206+)-like subpopulations. MIA significantly reduced M1 but increased mixed M1/M2 microglia, which was associated with upregulation of numerous cytokines with pleotropic property. MIA resulted in a robust increase in Ki67+/Nestin+ and Tbr2+ neural progenitor cells in the subventricular zone (SVZ) of newborn mice. At juvenile stage, a male-specific reduction of Parvalbumin+ but increase in Reelin+ interneurons in the medial prefrontal cortex was found in MIA offspring mice. MIA programs microglia towards a pleotropic phenotype that may drive excessive neurogenesis in ASD patients. Maternal immune activation (MIA) alters microglial phenotypes in the brain of fetal and neonatal mouse offspring. MIA leads to excessive proliferation and overproduction of neural progenitors in the subventricular zone (SVZ). MIA reduces parvalbumin+ while increases Reelin+ interneurons in the prefrontal cortex. Our study sheds light on neurobiological mechanisms of abnormal neurogenesis in certain neurodevelopmental disorders, such as autism spectrum disorder (ASD).