Development and Disorders of the Airway in Bronchopulmonary Dysplasia.

Bronchopulmonary dysplasia (BPD), a disorder characterized by arrested lung development, is a frequent cause of morbidity and mortality in premature infants. Parenchymal lung changes in BPD are relatively well-characterized and highly studied; however, there has been less emphasis placed on the role that airways disease plays in the pathophysiology of BPD. In preterm infants born between 22 and 32 weeks gestation, the conducting airways are fully formed but still immature and therefore susceptible to injury and further disruption of development. The arrest of maturation results in more compliant airways that are more susceptible to deformation and damage. Consequently, neonates with BPD are prone to developing airway pathology, particularly for patients who require intubation and positive-pressure ventilation. Airway pathology, which can be divided into large and small airways disease, results in increased respiratory morbidity in neonates with chronic lung disease of prematurity.

Evaluation of 2-year outcomes in infants born to mothers with and without NAFLD in pregnancy.

Nonalcoholic fatty liver disease (NAFLD) affects an estimated 17% of pregnant patients in the USA. However, there are limited data on the impact of maternal NAFLD on pediatric outcomes. We prospectively evaluated outcomes in infants born to mothers with and without NAFLD in pregnancy over their first 2 years of life. Maternal subjects were identified through an ongoing prospective study in which pregnant individuals were screened for NAFLD. Pediatric outcomes of infants born to these mothers-including adverse neonatal outcomes and weight and weight-for-length percentile at 6, 12, 18, and 24 months-were prospectively evaluated. Multivariate logistic regression was performed to evaluate the association of maternal NAFLD with pediatric outcomes, as well as to adjust for potentially confounding maternal characteristics. Six hundred thirty-eight infants were included in our cohort. The primary outcomes assessed were weight and growth throughout the first 2 years of life. Maternal NAFLD was also not associated with increased infant birth weight or weight-for-gestational-age percentile or weight or weight-for-length percentile over the first 2 years of life. Maternal NAFLD was significantly associated with very premature delivery before 32 weeks, even after adjustment for confounding maternal characteristics (aOR = 2.83, p = 0.05). Maternal NAFLD was also significantly associated with neonatal jaundice, including after adjusting for maternal race (aOR = 1.67, p = 0.03). However, maternal NAFLD was not significantly associated with any other adverse neonatal outcomes.    Conclusion: Maternal NAFLD may be independently associated with very premature birth and neonatal jaundice but was not associated with other adverse neonatal outcomes. Maternal NAFLD was also not associated with any differences in infant growth over the first 2 years of life. What is Known: • Maternal NAFLD in pregnancy may be associated with adverse pregnancy and neonatal outcomes, but the findings are inconsistent across the literature. What is New: • Maternal NAFLD is not associated with any differences in weight at birth or growth over the first 2 years of life. • Maternal NAFLD is associated with very premature delivery and neonatal jaundice, but is not associated with other adverse neonatal outcomes.

Real-Time Ultrasound Guidance for Umbilical Venous Cannulation in Neonates With Congenital Heart Disease.

OBJECTIVES: Umbilical venous cannulation is the favored approach to perinatal central access worldwide but has a failure rate of 25-50% and the insertion technique has not evolved in decades. Improving the success of this procedure would have broad implications, particularly where peripherally inserted central catheters are not easily obtained and in neonates with congenital heart disease, in whom umbilical access facilitates administration of inotropes and blood products while sparing vessels essential for later cardiac interventions. We sought to use real-time, point-of-care ultrasound to achieve central umbilical venous access in patients for whom conventional, blind placement techniques had failed. DESIGN: Multicenter case series, March 2019-May 2021. SETTING: Cardiac and neonatal ICUs at three tertiary care children's hospitals. PATIENTS: We identified 32 neonates with congenital heart disease, who had failed umbilical venous cannulation using traditional, blind techniques. INTERVENTIONS: Real-time ultrasound guidance and liver pressure were used to replace malpositioned catheters and achieve successful placement at the inferior cavoatrial junction. MEASUREMENTS AND MAIN RESULTS: In 32 patients with failed prior umbilical venous catheter placement, real-time ultrasound guidance was used to successfully "rescue" the line and achieve central position in 23 (72%). Twenty of 25 attempts (80%) performed in the first 48 hours of life were successful, and three of seven attempts (43%) performed later. Twenty-four patients (75%) were on prostaglandin infusion at the time of the procedure. We did not identify an association between patient weight or gestational age and successful placement. CONCLUSIONS: Ultrasound guidance has become standard of care for percutaneous central venous access but is a new and emerging technique for umbilical vessel catheterization. In this early experience, we report that point-of-care ultrasound, together with liver pressure, can be used to markedly improve success of placement. This represents a significant advance in this core neonatal procedure.

Developmental window of vulnerability to white matter injury driven by sublethal intermittent hypoxemia.

BACKGROUND: In the developing brain, the death of immature oligodendrocytes (OLs) has been proposed to explain a developmental window for vulnerability to white matter injury (WMI). However, in neonatal mice, chronic sublethal intermittent hypoxia (IH) recapitulates the phenotype of diffuse WMI without affecting cellular viability. This work determines whether, in neonatal mice, a developmental window of WMI vulnerability exists in the absence of OLs lineage cellular death. METHODS: Neonatal mice were exposed to cell-nonlethal early or late IH stress. The presence or absence of WMI phenotype in their adulthood was defined by the extent of sensorimotor deficit and diffuse cerebral hypomyelination. A separate cohort of mice was examined for markers of cellular degeneration and OLs maturation. RESULTS: Compared to normoxic littermates, only mice exposed to early IH stress demonstrated arrested OLs maturation, diffuse cerebral hypomyelination, and sensorimotor deficit. No cellular death associated with IH was detected. CONCLUSIONS: Neonatal sublethal IH recapitulates the phenotype of diffuse WMI only when IH stress coincides with the developmental stage of primary white matter myelination. This signifies a contribution of cell-nonlethal mechanisms in defining the developmental window of vulnerability to diffuse WMI. IMPACT: The key message of our work is that the developmental window of vulnerability to the WMI driven by intermittent hypoxemia exists even in the absence of excessive OLs and other cells death. This is an important finding because the existence of the developmental window of vulnerability to WMI has been explained by a lethal-selective sensitivity of immature OLs to hypoxic and ischemic stress, which coincided with their differentiation. Thus, our study expands mechanistic explanation of a developmental window of sensitivity to WMI by showing the existence of cell-nonlethal pathways responsible for this biological phenomenon.

Mild intermittent hypoxemia in neonatal mice causes permanent neurofunctional deficit and white matter hypomyelination.

Very low birth weight (VLBW) premature infants experience numerous, often self-limited non-bradycardic episodes of intermittent hypoxemia (IH). We hypothesized that these episodes of IH affect postnatal white matter (WM) development causing hypomyelination and neurological handicap in the absence of cellular degeneration. Based on clinical data from ten VLBW neonates; a severity, daily duration and frequency of non-bradycardic IH episodes were reproduced in neonatal mice. Changes in heart rate and cerebral blood flow during IH were recorded. A short-term and long-term neurofunctional performance, cerebral content of myelin basic protein (MBP), 2'3' cyclic-nucleotide 3-phosphodiesterase (CNPase), electron microscopy of axonal myelination and the extent of cellular degeneration were examined. Neonatal mice exposed to IH exhibited no signs of cellular degeneration, yet demonstrated significantly poorer olfactory discrimination, wire holding, beam and bridge crossing, and walking-initiation tests performance compared to controls. In adulthood, IH-mice demonstrated no alteration in navigational memory. However, sensorimotor performance on rota-rod, wire-holding and beam tests was significantly worse compared to naive littermates. Both short- and long-term neurofunctional deficits were coupled with decreased MBP, CNPase content and poorer axonal myelination compared to controls. In neonatal mice mild, non-ischemic IH stress, mimicking that in VLBW preterm infants, replicates a key phenotype of non-cystic WM injury: permanent hypomyelination and sensorimotor deficits. Because this phenotype has developed in the absence of cellular degeneration, our data suggest that cellular mechanisms of WM injury induced by mild IH differ from that of cystic periventricular leukomalacia where the loss of myelin-producing cells and axons is the major mechanism of injury.

Developmental expression patterns of the zebrafish small heat shock proteins.

Small heat shock proteins (sHSPs), or alpha-crystallins, are low-molecular weight proteins found in every kingdom and nearly every species examined to date. Many, if not all, sHSPs act as molecular chaperones. Several also have functions independent of their chaperone activity, and at least a few are expressed in specific spatiotemporal patterns during embryonic and/or juvenile stages, suggesting specific roles during development. To date, however, no one has systematically characterized the expression patterns of all of the sHSPs during development in any organism. We have characterized the normal heat shock-induced expression patterns of all 13 zebrafish sHSPs during development. Seven of the sHSPs are expressed in a tissue-specific manner during development, and five are upregulated by heat shock. The results of these studies provide a foundation for analysis of sHSP function during normal development and their roles in protecting cells from the effects environmental stressors.