Translational 3D-Cell Culture Model to Assess Hyperoxia Effects on Human Neonatal Airway Epithelial Cells.

The preterm neonatal airway epithelium is constantly exposed to environmental stressors. One of these stressors in neonates with lung disease includes oxygen (O2) tension higher than the ambient atmosphere - termed hyperoxia (>21% O2). The effect of hyperoxia on the airway depends on various factors, including the developmental stage of the airway, the degree of hyperoxia, and the duration of exposure, with variable exposures potentially leading to unique phenotypes. While there has been extensive research on the effect of hyperoxia on neonatal lung alveolarization and airway hyperreactivity, little is known about the short and long-term underlying effect of hyperoxia on human neonatal airway epithelial cells. A major reason for this is the scarcity of an effective in vitro model to study human neonatal airway epithelial development and function. Here, we describe a method for isolating and expanding human neonatal tracheal airway epithelial cells (nTAECs) utilizing human neonatal tracheal aspirates and culturing these cells in air-liquid interface (ALI) culture. We demonstrate that nTAECs form a mature polarized cell-monolayer in ALI culture and undergo mucociliary differentiation. We also present a method for moderate hyperoxia exposure of the cell monolayer in ALI culture using a specialized incubator. Additionally, we describe an assay to measure cellular oxidative stress following hyperoxia exposure in ALI culture using fluorescent quantification, which confirms that moderate hyperoxia exposure induces cellular oxidative stress but does not cause significant cell membrane damage or apoptosis. This model can potentially be used to simulate clinically relevant hyperoxia exposure encountered by neonatal airways in the Neonatal Intensive Care Unit (NICU) and used to study the short and long-lasting effects of O2 on neonatal airway epithelial programming. Studies using this model could be utilized to explore ways to mitigate early-life oxidative injury to developing airways, which is implicated in the development of long-term airway diseases in former premature infants.

Supplemental Oxygen in the Newborn: Historical Perspective and Current Trends.

Oxygen is the final electron acceptor in aerobic respiration, and a lack of oxygen can result in bioenergetic failure and cell death. Thus, administration of supplemental concentrations of oxygen to overcome barriers to tissue oxygen delivery (e.g., heart failure, lung disease, ischemia), can rescue dying cells where cellular oxygen content is low. However, the balance of oxygen delivery and oxygen consumption relies on tightly controlled oxygen gradients and compartmentalized redox potential. While therapeutic oxygen delivery can be life-saving, it can disrupt growth and development, impair bioenergetic function, and induce inflammation. Newborns, and premature newborns especially, have features that confer particular susceptibility to hyperoxic injury due to oxidative stress. In this review, we will describe the unique features of newborn redox physiology and antioxidant defenses, the history of therapeutic oxygen use in this population and its role in disease, and clinical trends in the use of therapeutic oxygen and mitigation of neonatal oxidative injury.

Neonatal Extracellular Superoxide Dismutase Knockout Mice Increase Total Superoxide Dismutase Activity and VEGF Expression after Chronic Hyperoxia.

Bronchopulmonary dysplasia (BPD) is a common lung disease affecting premature infants that develops after exposure to supplemental oxygen and reactive oxygen intermediates. Extracellular superoxide dismutase (SOD3) is an enzyme that processes superoxide radicals and has been shown to facilitate vascular endothelial growth factor (VEGF) and nitric oxide (NO) signaling in vascular endothelium. We utilized a mouse model of neonatal hyperoxic lung injury and SOD3 knockout (KO) mice to evaluate its function during chronic hyperoxia exposure. Wild-type age-matched neonatal C57Bl/6 (WT) and SOD3-/- (KO) mice were placed in normoxia (21% FiO2, RA) or chronic hyperoxia (75% FiO2, O2) within 24 h of birth for 14 days continuously and then euthanized. Lungs were harvested for histologic evaluation, as well as comparison of antioxidant enzyme expression, SOD activity, VEGF expression, and portions of the NO signaling pathway. Surprisingly, KO-O2 mice survived without additional alveolar simplification, microvascular remodeling, or nuclear oxidation when compared to WT-O2 mice. KO-O2 mice had increased total SOD activity and increased VEGF expression when compared to WT-O2 mice. No genotype differences were noted in intracellular antioxidant enzyme expression or the NO signaling pathway. These results demonstrate that SOD3 KO mice can survive prolonged hyperoxia without exacerbation of alveolar or vascular phenotype.

Placental vascular maldevelopment, intrauterine growth restriction, and pulmonary hypertension.

A 33-year-old gravida 2, para 1 woman was noted to have early intrauterine growth restriction at 22 weeks gestation and subsequently developed severe pre-eclampsia. She delivered a 460 g male neonate at 28 weeks. The infant was managed on non-invasive ventilatory support and was gaining weight on enteral feeds for the first eight weeks of life, at which point he developed necrotizing enterocolitis. He then developed severe pulmonary hypertension that was refractory to maximal medical management. He died at 10 weeks of life due to hypoxemic respiratory and heart failure. Placental pathology revealed a constellation of findings consistent with maternal vascular malperfusion. Lung autopsy revealed muscularized and hypertrophied pulmonary arterioles consistent with severe pulmonary hypertension. Von Willebrand factor immunofluorescent staining of autopsy specimens suggest parallels in extent of endothelial injury. This case study illustrates our evolving knowledge of the fetal origins of neonatal lung diseases.

Patients in a private hospital in India leave the emergency department against medical advice for financial reasons.

BACKGROUND: Some reports indicate financial concerns as a factor affecting ED patients leaving the acute care setting against medical advice (AMA). In India, no person is supposed to be denied urgent care because of inability to pay. Since a large proportion of the Indian health care system is financed by out-of-pocket expenses, we investigate the role of financial constraints for ED patients at a private hospital in India in leaving AMA. METHODS: A prospective ED-based cross-sectional survey of patients leaving AMA was conducted at a private hospital in India from 1 October 2010 to 31 December 2010. Descriptive statistics and the chi-square test were used to identify associations between financial factors and the decision to leave the hospital AMA. RESULTS: Overall, 55 (3.84%) ED patients left AMA, of which 46 (84%) reported leaving because of financial restrictions. Thirty-nine (71%) respondents indicated the medical bill would represent more that 25% of their annual income. Females (19/19) were more likely to leave AMA for financial reasons compared to males (27/36, p = 0.017). Among females who signed out AMA, the decision was never made by the female herself. CONCLUSION: The number of people leaving the ED AMA in a private Indian hospital is relatively high, with most leaving for financial reasons. In most cases, women did not decide to leave the ED AMA for themselves, whereas males did. This survey suggests that steps are needed to ensure that the inability to pay does not prevent emergent care from being provided.

The livelihoods of Haitian health-care providers after the january 2010 earthquake: a pilot study of the economic and quality-of-life impact of emergency relief.

INTRODUCTION: An effective international response to a disaster requires cooperation and coordination with the existing infrastructure. In some cases, however, international relief efforts can compete with the local work force and affect the balance of health-care systems already in place. This study seeks to evaluate the impact of the international humanitarian response to the 12 January 2010 earthquake on Haitian health-care providers (HHP). METHODS: Fifty-nine HHPs were surveyed in August of 2010 using a modified World Health Organization Quality of Life-Brief questionnaire (WHOQoL-B) that included questions on respondents' workload before the earthquake, immediately after, and presently. The study population consisted of physicians, nurses, and technicians at public hospitals, non-governmental organization (NGO) clinics, and private offices in Port-au-Prince, Haiti. RESULTS: Following the earthquake, public hospital and NGO providers reported a significant increase in their workload (15 of 17 and 22 of 26 respondents, respectively). Conversely, 12 of 16 private providers reported a significant decrease in workload (p < 0.0001). Although all groups reported working a similar number of hours prior to the earthquake (average 40 h/week), they reported working significantly different amounts following the earthquake. Public hospital and NGO providers averaged more than 50 h/week, and private providers averaged just over 33 h/week of employment (p < 0.001).Health-care providers working at public hospitals and NGOs, however, had significantly lower scores on the WHOQoL-B when answering questions about their environment (p < 0.001), and in open-ended responses often commented about the lack of potable water and poor access to toilets. Providers from all groups expressed dissatisfaction with the scope and quality of care provided at public hospitals and NGO clinics, as well as disappointment with the reduction in patient volume at private practices. CONCLUSIONS: The emergency medical response to the January 2010 earthquake in Haiti had the unintended consequence of poorly distributing work among HHPs. To create a robust health-care system in the long term while meeting short-term needs, humanitarian responses should seek to better integrate existing systems and involve local providers in the design and implementation of an emergency program.