Defining Longer-Term Outcomes in an Ovine Model of Moderate Perinatal Hypoxia-Ischemia.

Hypoxic-ischemic encephalopathy (HIE) is the leading cause of neonatal morbidity and mortality worldwide. Approximately 1 million infants born with HIE each year survive with cerebral palsy and/or serious cognitive disabilities. While infants born with mild and severe HIE frequently result in predictable outcomes, infants born with moderate HIE exhibit variable outcomes that are highly unpredictable. Here, we describe an umbilical cord occlusion (UCO) model of moderate HIE with a 6-day follow-up. Near-term lambs (n = 27) were resuscitated after the induction of 5 min of asystole. Following recovery, lambs were assessed to define neurodevelopmental outcomes. At the end of this period, lambs were euthanized, and brains were harvested for histological analysis. Compared with prior models that typically follow lambs for 3 days, the observation of neurobehavioral outcomes for 6 days enabled identification of animals that recover significant neurological function. Approximately 35% of lambs exhibited severe motor deficits throughout the entirety of the 6-day course and, in the most severely affected lambs, developed spastic diparesis similar to that observed in infants who survive severe neonatal HIE (severe, UCOs). Importantly, and similar to outcomes in human neonates, while initially developing significant acidosis and encephalopathy, the remainder of the lambs in this model recovered normal motor activity and exhibited normal neurodevelopmental outcomes by 6 days of life (improved, UCOi). The UCOs group exhibited gliosis and inflammation in both white and gray matters, oligodendrocyte loss, neuronal loss, and cellular death in the hippocampus and cingulate cortex. While the UCOi group exhibited more cellular death and gliosis in the parasagittal cortex, they demonstrated more preserved white matter markers, along with reduced markers of inflammation and lower cellular death and neuronal loss in Ca3 of the hippocampus compared with UCOs lambs. Our large animal model of moderate HIE with prolonged follow-up will help further define pathophysiologic drivers of brain injury while enabling identification of predictive biomarkers that correlate with disease outcomes and ultimately help support development of therapeutic approaches to this challenging clinical scenario.

Characterization of Disease Phenotype in Very Preterm Infants with Severe Bronchopulmonary Dysplasia.

Rationale: Bronchopulmonary dysplasia (BPD) is a heterogenous condition with poorly characterized disease subgroups.Objectives: To define the frequency of three disease components: moderate-severe parenchymal disease, pulmonary hypertension (PH), or large airway disease, in a referral cohort of preterm infants with severe BPD. The association between each component and a primary composite outcome of death before hospital discharge, tracheostomy, or home pulmonary vasodilator therapy was assessed.Methods: This was a retrospective, single-center cohort study of infants born at <32 weeks' gestation with severe BPD who underwent both chest computed tomography with angiography (CTA) and echocardiography between 40 and 50 weeks postmenstrual age between 2011 and 2015. Moderate-severe parenchymal lung disease was defined as an Ochiai score ≥8 on CTA. PH was diagnosed by echocardiogram using standard criteria. Large airway disease was defined as tracheomalacia or bronchomalacia on bronchoscopy and/or tracheoscopy or CTA.Measurements and Main Results: Of 76 evaluated infants, 73 (96%) were classifiable into phenotypic subgroups: 57 with moderate-severe parenchymal disease, 48 with PH, and 44 with large airway disease. The presence of all three disease components was most common (n = 23). Individually, PH and large airway disease, but not moderate-severe parenchymal disease, were associated with increased risk for the primary study outcome. Having more disease components was associated with an incremental increase in the risk for the primary outcome (2 vs. 1: odds ratio, 4.9; 95% confidence interval, 1.4-17.2 and 3 vs. 1: odds ratio, 12.8; 95% confidence interval, 2.4-70.0).Conclusions: Infants with severe BPD are variable in their predominant pathophysiology. Disease phenotyping may enable better risk stratification and targeted therapeutic intervention.

HIF-1α promotes cellular growth in lymphatic endothelial cells exposed to chronically elevated pulmonary lymph flow.

Normal growth and development of lymphatic structures depends on mechanical forces created by accumulating interstitial fluid. However, prolonged exposure to pathologic mechanical stimuli generated by chronically elevated lymph flow results in lymphatic dysfunction. The mechanisms that transduce these mechanical forces are not fully understood. Our objective was to investigate molecular mechanisms that alter the growth and metabolism of isolated lymphatic endothelial cells (LECs) exposed to prolonged pathologically elevated lymph flow in vivo within the anatomic and physiologic context of a large animal model of congenital heart disease with increased pulmonary blood flow using in vitro approaches. To this end, late gestation fetal lambs underwent in utero placement of an aortopulmonary graft (shunt). Four weeks after birth, LECs were isolated and cultured from control and shunt lambs. Redox status and proliferation were quantified, and transcriptional profiling and metabolomic analyses were performed. Shunt LECs exhibited hyperproliferative growth driven by increased levels of Hypoxia Inducible Factor 1α (HIF-1α), along with upregulated expression of known HIF-1α target genes in response to mechanical stimuli and shear stress. Compared to control LECs, shunt LECs exhibited abnormal metabolism including abnormalities of glycolysis, the TCA cycle and aerobic respiration. In conclusion, LECs from lambs exposed in vivo to chronically increased pulmonary lymph flow are hyperproliferative, have enhanced expression of HIF-1α and its target genes, and demonstrate altered central carbon metabolism in vitro. Importantly, these findings suggest provocative therapeutic targets for patients with lymphatic abnormalities.

An Atypical Presentation of Alagille Syndrome.

Alagille syndrome is a multisystem disorder classically involving the liver, heart, vertebrae, facial features, and the eyes. In this case report, we document a case of Alagille syndrome with an atypical clinical and histopathologic presentation and subsequent identification of a novel JAG1 missense mutation. This case highlights that there may be both atypical clinical and pathologic findings in mutation-proven Alagille syndrome and that the diagnosis of Alagille syndrome should be considered in cases of ongoing bile duct damage in the setting of early-onset jaundice, cholestasis, hepatosplenomegaly, posterior embryotoxon in the eyes, and butterfly vertebrae.

Predicting the need for laser treatment in retinopathy of prematurity using computer-assisted quantitative vascular analysis.

PURPOSE: To investigate whether parameters of retinal vascular dilation and/or tortuosity calculated by ROPtool software can help to predict, prior to diagnosis of plus disease, whether laser will be needed for treatment of retinopathy of prematurity (ROP). METHODS: Video indirect ophthalmoscopy recordings were obtained during routine ROP examinations. One posterior pole still image of one eye was selected from each examination for each infant. ROPtool was used to calculate vessel dilation, tortuosity, and the sum of adjusted indices (SAI, combining dilation and tortuosity) for each image. The following values were calculated for each vessel characteristic: maximum value from any one vessel across all examinations, largest increase per week in maximum value, highest mean value of all vessels from any one examination, and largest increase per week in mean value. These parameters were compared between infants who eventually received laser and those who did not. RESULTS: Medians for maximum tortuosity indices were, for the eventual laser group (n = 28), 8.92 tortuosity units and, for the no laser group (n = 56), 6.87 (P < 0.001). Medians for highest mean tortuosity indices were 4.95 tortuosity units for the eventual laser group and 3.66 for the no laser group (P < 0.001). Parameters involving dilation and SAI did not differ significantly between groups. In multivariable analysis, highest mean tortuosity was associated with need for laser (P = 0.003). CONCLUSIONS: ROPtool analysis of tortuosity parameters from indirect ophthalmoscopy images can help predict need for laser in ROP.

Current and future trends in treatment of severe retinopathy of prematurity.

Treatment for retinopathy of prematurity (ROP) is indicated when type 1 disease is present. The Early Treatment for Retinopathy of Prematurity (ETROP) clinical trial established that laser treatment of severe ROP has a high rate of visual and anatomic success. Recently, anti-vascular endothelial growth factor (VEGF) drugs such as bevacizumab have been used in lieu of or in addition to laser treatment. Results are promising, but long-term outcomes and systemic side effects are unknown. Future studies are needed to determine whether anti-VEGF treatment is superior to laser and, if so, which drug and dose are safe and effective.