Altered pulmonary lymphatic development in infants with chronic lung disease

Bronchopulmonary Dysplasia-Associated Pulmonary Hypertension: Basing Care on Physiology

Bronchopulmonary dysplasia (BPD) is the heterogeneous chronic lung developmental disease of prematurity, which is often accompanied by multisystem comorbidities. Pulmonary vascular disease and pulmonary hypertension (PH) contribute significantly to the pathogenesis and pathophysiology of BPD and dramatically influence the outcomes of preterm infants with BPD. When caring for those patients, clinicians should consider the multitude of phenotypic presentations that fall under the "BPD-PH umbrella," reflecting the need for matching therapies to specific physiologies to improve short- and long-term outcomes. Individualized management based on the patient's prenatal and postnatal risk factors, clinical course, and cardiopulmonary phenotype needs to be identified and prioritized to provide optimal care for infants with BPD-PH.

Neonatal perspective on central lymphatic disorders

Lymphatic disorders presenting in the first year of life are difficult to identify and manage given the broad range of underlying etiologies. Neonatal lymphatic disease arising from congenital or acquired conditions results in the abnormal accumulation of lymph fluid in the pleura (chylothorax), peritoneum (chylous ascites) and skin (edema/anasarca). There is also increasing recognition of lymphatic losses through the intestine resulting in protein-losing enteropathy (PLE). While the incidence of lymphatic disorders in neonates is unclear, advances in genetic testing and lymphatic imaging are improving our understanding of the underlying pathophysiology. Despite these advancements, medical management of neonatal lymphatic disorders remains challenging and variable among clinicians.

Hyperoxia Disrupts Lung Lymphatic Homeostasis in Neonatal Mice

Inflammation causes bronchopulmonary dysplasia (BPD), a common lung disease of preterm infants. One reason this disease lacks specific therapies is the paucity of information on the mechanisms regulating inflammation in developing lungs. We address this gap by characterizing the lymphatic phenotype in an experimental BPD model because lymphatics are major regulators of immune homeostasis. We hypothesized that hyperoxia (HO), a major risk factor for experimental and human BPD, disrupts lymphatic endothelial homeostasis using neonatal mice and human dermal lymphatic endothelial cells (HDLECs). Exposure to 70% O2 for 24-72 h decreased the expression of prospero homeobox 1 (Prox1) and vascular endothelial growth factor c (Vegf-c) and increased the expression of heme oxygenase 1 and NAD(P)H dehydrogenase [quinone]1 in HDLECs, and reduced their tubule formation ability. Next, we determined Prox1 and Vegf-c mRNA levels on postnatal days (P) 7 and 14 in neonatal murine lungs. The mRNA levels of these genes increased from P7 to P14, and 70% O2 exposure for 14 d (HO) attenuated this physiological increase in pro-lymphatic factors. Further, HO exposure decreased VEGFR3+ and podoplanin+ lymphatic vessel density and lymphatic function in neonatal murine lungs. Collectively, our results validate the hypothesis that HO disrupts lymphatic endothelial homeostasis.

The Clinical Evaluation of Severe Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia is a common disease of prematurity that presents along a wide spectrum of disease severity. Infants with high severity require prolonged hospitalizations and benefit from multidisciplinary care. We describe our approach to the evaluation of infants with severe bronchopulmonary dysplasia. Important considerations include the phenotypic heterogeneity in clinical presentation that necessitates individualized care, the common presence of comorbidities and importance of a comprehensive multisystem evaluation, and the value of applying a chronic care model that prioritizes long-term respiratory and neurodevelopmental goals. Key features of the history, physical examination, and diagnostic studies are discussed with these considerations in mind.

Cocaine enhances HIV-1 gp120-induced lymphatic endothelial dysfunction in the lung

Pulmonary complications are common in both AIDS patients and cocaine users. We addressed the cellular and molecular mechanisms by which HIV and cocaine may partner to induce their deleterious effects. Using primary lung lymphatic endothelial cells (L-LECs), we examined how cocaine and HIV-1 gp120, alone and together, modulate signaling and functional properties of L-LECs. We found that brief cocaine exposure activated paxillin and induced cytoskeletal rearrangement, while sustained exposure increased fibronectin (FN) expression, decreased Robo4 expression, and enhanced the permeability of L-LEC monolayers. Moreover, incubating L-LECs with both cocaine and HIV-1 gp120 exacerbated hyperpermeability, significantly enhanced apoptosis, and further impaired in vitro wound healing as compared with cocaine alone. Our studies also suggested that the sigma-1 receptor (Sigma-1R) and the dopamine-4 receptor (D4R) are involved in cocaine-induced pathology in L-LECs. Seeking clinical correlation, we found that FN levels in sera and lung tissue of HIV(+) donors were significantly elevated as compared to HIV(-) donors. Our in vitro data demonstrate that cocaine and HIV-1 gp120 induce dysfunction and damage of lung lymphatics, and suggest that cocaine use may exacerbate pulmonary edema and fibrosis associated with HIV infection. Continued exploration of the interplay between cocaine and HIV should assist the design of therapeutics to ameliorate HIV-induced pulmonary disorders within the drug using population.