TRIP-1 via AKT modulation drives lung fibroblast/myofibroblast trans-differentiation

Abstract Background Myofibroblasts are the critical effector cells in the pathogenesis of pulmonary fibrosis which carries a high degree of morbidity and mortality. We have previously identified Type II TGFβ receptor interacting protein 1 (TRIP-1), through proteomic analysis, as a key regulator of collagen contraction in primary human lung fibroblasts—a functional characteristic of myofibroblasts, and the last, but critical step in the process of fibrosis. However, whether or not TRIP-1 modulates fibroblast trans-differentiation to myofibroblasts is not known. Methods TRIP-1 expression was altered in primary human lung fibroblasts by siRNA and plasmid transfection. Transfected fibroblasts were then analyzed for myofibroblast features and function such as α-SMA expression, collagen contraction ability, and resistance to apoptosis. Results The down-regulation of TRIP-1 expression in primary human lung fibroblasts induces α-SMA expression and enhances resistance to apoptosis and collagen contraction ability. In contrast, TRIP-1 over-expression inhibits α-SMA expression. Remarkably, the effects of the loss of TRIP-1 are not abrogated by blockage of TGFβ ligand activation of the Smad3 pathway or by Smad3 knockdown. Rather, a TRIP-1 mediated enhancement of AKT phosphorylation is the implicated pathway. In TRIP-1 knockdown fibroblasts, AKT inhibition prevents α-SMA induction, and transfection with a constitutively active AKT construct drives collagen contraction and decreases apoptosis. Conclusions TRIP-1 regulates fibroblast acquisition of phenotype and function associated with myofibroblasts. The importance of this finding is it suggests TRIP-1 expression could be a potential target in therapeutic strategy aimed against pathological fibrosis.Peer Reviewe

Hyperinsulinemic hypoglycemia in growth restricted convalescent preterm neonates: clinical characteristics and impediments to early diagnosis

Abstract Objectives Describe clinical characteristics, course, and risk factors for hyper-insulinemic hypoglycemia (HIH) in preterm infants and identify impediments to early diagnosis. Methods Electronic records of infant–mother dyads were used to describe clinical characteristics, lab parameters, and course of HIH. Results All eight patients (gestational ages 26w0d–29w3d) had intrauterine growth restriction (IUGR) due to placental insufficiency, (4/8) were small for gestational age. All maintained normal glucose levels with glucose infusion during the first 48 h six of eight patients had cholestasis despite being on parenteral nutrition for short time (average 17 days). Four of eight patients were treated with diazoxide (average 22 days). Four of eight patients who recovered spontaneously (average 49 days after diagnosis) responded to continuous feeds and hydrocortisone for other clinical indications. Conclusions In IUGR preterms, HIH is asymptomatic, may be prolonged, requiring diazoxide treatment. Transient cholestasis is seen in majority of patients. Euglycemia should be demonstrated on bolus gavage feeds, off glucocorticoids before discontinuing blood glucose monitoring. </jats:sec

A Case Series of Four Preterm Intrauterine Growth Restricted Babies With Transient Hyper-Insulinemic Hypoglycemia and Cholestasis

Abstract Background: Premature infants with intrauterine growth restriction (IUGR) are predisposed to stress related hyper Insulinemic hypoglycemia (HIH). These babies are at risk for other prematurity related complications including direct hyperbilirubinemia. However, association of HIH with this has not been described, and transient cholestasis in HIH infants has not been reported. We present 4 such infants with perinatal stress related HIH who had cholestasis that resolved with time. Case series: In our retrospective review of these preemies with IUGR who had developed HIH, we found that 4 infants developed direct hyperbilirubinemia. Their gestational ages at birth ranged between 26 to 27 weeks, with birth weights between 527 to 642 grams. These infants had received total parenteral nutrition (TPN) for durations ranging between 12 to 19 days of life (DOL). HIH was established in them at variable ages between 55 to 75 DOL, based on an exaggerated glycemic response to glucagon. Of these, 1 baby was not started on Diazoxide due to underlying fluid overload. His HIH resolved by DOL 182. Two babies responded to therapy and while one remained on this till its resolution at 9 months age, another had the Diazoxide discontinued due to acute respiratory worsening leading to readmission. HIH in the latter resolved by 109 DOL. Fasting The last baby developed fluid overload early in therapy leading to its discontinuation without establishing response. Hypoglycemia in these infants resolved by ages between 4 to 9 months of life. Interestingly direct hyperbilirubinemia was noted by age 16 to 59 DOL. In all infants, the diagnosis of HIH was established after the onset of cholestasis. Extensive work up for hyperbilirubinemia ruled out any organic pathology. This transient cholestasis was noted to have resolved by ages 80 to 115 DOL. Conclusion: It appears from our experience in these premature infants, cholestasis may be associated with HIH. Its diagnosis preceded the establishment of HIH. We noted that HIH diagnosis was delayed by around 30 days after the onset of intermittent hypoglycemia. Both the cholestasis and HIH were transient. Whether the cholestasis may prognosticate the development of HIH or is indicative of transient HIH needs to be investigated. Any association between the two needs to be studied to address a common causality. IUGR babies with conjugated hyperbilirubinemia develop a mild and transient HI state which is self-resolving. Due to transient nature of this HIH in these IUGR babies with cholestasis, a genetic work up for HIH may be deferred.</jats:p

Outcomes of Infants Who Failed to Extubate despite Systemic Corticosteroids

Objective The objective of this study was to assess the outcomes of preterm infants who failed to extubate following initial treatment with steroids. Materials and Methods This is a retrospective cohort study of ventilator-dependent preterm infants treated with first course of systemic steroids to facilitate extubation. Outcomes of infants who successfully extubated were compared with infants who failed to extubate. Results In this study, 74 infants (mean gestation 25.4 ± 1.4 weeks and mean birth weight 764 ± 163 g) met inclusion criteria. Of these, 41 (55%) were successfully extubated and 33 (45%) were not. Baseline demographics were similar between the two groups. The primary outcome of severe bronchopulmonary dysplasia (BPD) or death at 36 weeks was higher among infants who failed to extubate (94 vs. 63%, p = 0.002). Severe BPD remained significantly higher even after adjustment for potential confounders (odds ratio: 12.2, 95% confidence interval: 2.1–70.5, p = 0.005). Extubation failure was also associated with substantially higher rate of tracheostomy (32 vs. 5%, p = 0.003) and gastrostomy tube placement (61 vs. 22%, p = 0.001), as well as longer days of hospitalization (179 ± 72 vs. 129 ± 44 days, p = 0.001) and mechanical ventilation (112 ± 89 vs. 52 ± 42 days, p &lt; 0.001). Conclusion Failure to extubate after first course of systemic steroids for BPD is associated with poor prognostic implications.</jats:p

Clinical Outcomes among Diagnostic Subgroups of Infants with Severe Bronchopulmonary Dysplasia through 2 Years of Age

Objective This article aimed to identify readmission risk factors through 2 years of life for infants with severe bronchopulmonary dysplasia (BPD) who do not require tracheostomy and ventilatory support after neonatal intensive care unit (NICU) discharge. It also aimed to identify if clinical differences exist between the subcategories of severe BPD. Study Design A retrospective chart review was performed on 182 infants with severe BPD born between 2010 and 2015. A total of 130 infants met the inclusion criteria and were stratified into three groups based on their respiratory status at 36 weeks of gestational age: group A—oxygen (O2), group B—assisted ventilation (AV), group C—both O2 and AV. NICU clinical risk factors for readmission were assessed at set time points (6/12/18/24 months). Reasons for readmission were assessed for the entire cohort and severe BPD subgroups. Conclusion An NICU diagnosis of neurologic abnormality, necrotizing enterocolitis, invasive NICU infection, dysphagia, and O2 at NICU discharge differed between the three subgroups of severe BPD. The most common cause of readmission was viral respiratory tract infection. Inhaled steroid use remained stable over time, while oxygen use and diuretic use declined over time. Risk factors for readmission in the entire cohort included g-tube, O2 use, and diuretic use at 12 months. There was no significant difference in readmission rates between the three BPD subgroups.</jats:p

Acute Post-Tracheostomy Clinical Decompensations in Infants—Are There Predictive Markers?

Objective To report on the population of infants receiving a tracheostomy, identify acute post-tracheostomy clinical decompensations, and seek predictive markers associated with acute complications following the placement of a tracheostomy. Study Design Retrospective deidentified clinical data was provided by the Infant Pulmonary Data Repository at Children's Mercy Hospital, Kansas City. Data from infants undergoing tracheostomy from January 1, 2008 through September 30, 2016 were divided into one of two study groups based on clinical correlations: (1) no acute decompensations within 72 hours post-tracheostomy or (2) acute clinical decompensation defined as sustained escalation of respiratory care within the 72 hours following tracheostomy. Results Thirty-four percent of infants undergoing tracheostomy during this period developed acute post-tracheostomy clinical decompensations. Elevated pre-tracheostomy positive end expiratory pressure, mean airway pressure, and echocardiogram findings suggestive of pulmonary hypertension (PH) or ventricular dysfunction were associated with acute post-tracheostomy clinical decompensations. Additionally acute post-tracheostomy clinical decompensation was associated with higher rate of death prior to discharge. Conclusion Infants requiring higher respiratory support and infants with PH or ventricular dysfunction are at risk of acute post-tracheostomy clinical decompensation, thus identifying these patients may lead to better pre-tracheostomy counseling and potentially targeted treatments to decrease this risk.</jats:p

Delta-like 4 is required for pulmonary vascular arborization and alveolarization in the developing lung

The molecular mechanisms by which endothelial cells (ECs) regulate pulmonary vascularization and contribute to alveolar epithelial cell development during lung morphogenesis remain unknown. We tested the hypothesis that delta-like 4 (DLL4), an EC Notch ligand, is critical for alveolarization by combining lung mapping and functional studies in human tissue and DLL4-haploinsufficient mice (Dll4+/lacz). DLL4 expressed in a PECAM-restricted manner in capillaries, arteries, and the alveolar septum from the canalicular to alveolar stage in mice and humans. Dll4 haploinsufficiency resulted in exuberant, nondirectional vascular patterning at E17.5 and P6, followed by smaller capillaries and fewer intermediate blood vessels at P14. Vascular defects coincided with polarization of lung EC expression toward JAG1-NICD-HES1 signature and decreased tip cell-like (Car4) markers. Dll4+/lacZ mice had impaired terminal bronchiole development at the canalicular stage and impaired alveolarization upon lung maturity. We discovered that alveolar type I cell (Aqp5) markers progressively decreased in Dll4+/lacZ mice after birth. Moreover, in human lung EC, DLL4 deficiency programmed a hypersprouting angiogenic phenotype cell autonomously. In conclusion, DLL4 is expressed from the canalicular to alveolar stage in mice and humans, and Dll4 haploinsufficiency programs dysmorphic microvascularization, impairing alveolarization. Our study reveals an obligate role for DLL4-regulated angiogenesis in distal lung morphogenesis