Lance A. Parton

Plasma Biomarkers of Oxidative Stress: Relationship to Lung Disease and Inhaled Nitric Oxide Therapy in Premature Infants

OBJECTIVES. Inhaled nitric oxide treatment for ventilated premature infants improves survival without bronchopulmonary dysplasia. However, there has been no information regarding possible effects of this therapy on oxidative stress. We hypothesized that inhaled nitric oxide therapy would not influence concentrations of plasma biomarkers of oxidative stress. PATIENTS AND METHODS. As part of the Nitric Oxide Chronic Lung Disease Trial, we collected blood samples at specified intervals from a subpopulation of 100 infants of <1250 g birth weight who received inhaled nitric oxide (20 ppm, weaned to 2 ppm) or placebo gas for 24 days. Plasma was assayed for total protein and for 3-nitrotyrosine and carbonylation by using immunoassays. RESULTS. The demographic characteristics and primary outcome for the infants were representative of the entire group of infants who were in the Nitric Oxide Chronic Lung Disease Trial. For all infants at baseline, before receiving study gas, the concentration of total protein was inversely correlated with the respiratory severity score, and plasma carbonyl was positively correlated with severity score, supporting an association between oxidative stress and severity of lung disease. Infants who survived without bronchopulmonary dysplasia had 30% lower protein carbonylation concentrations at study entry than those who had an adverse outcome. At each of 3 time points (1–10 days) during exposure to study gas, there were no significant differences between control and treated infants for concentrations of plasma protein, 3-nitrotyrosine, and carbonylation. CONCLUSIONS. Inhaled nitric oxide treatment for premature infants who are at risk for bronchopulmonary dysplasia does not alter plasma biomarkers of oxidative stress, which supports the safety of this therapy.

Surfactant Function and Composition in Premature Infants Treated With Inhaled Nitric Oxide

OBJECTIVES. We hypothesized that inhaled nitric oxide treatment of premature infants at risk for bronchopulmonary dysplasia would not adversely affect endogenous surfactant function or composition. METHODS. As part of the Nitric Oxide Chronic Lung Disease Trial of inhaled nitric oxide, we examined surfactant in a subpopulation of enrolled infants. Tracheal aspirate fluid was collected at specified intervals from 99 infants with birth weights <1250 g who received inhaled nitric oxide (20 ppm, weaned to 2 ppm) or placebo gas for 24 days. Large-aggregate surfactant was analyzed for surface activity with a pulsating bubble surfactometer and for surfactant protein contents with an immunoassay. RESULTS. At baseline, before administration of study gas, surfactant function and composition were comparable in the 2 groups, and there was a positive correlation between minimum surface tension and severity of lung disease for all infants. Over the first 4 days of treatment, minimum surface tension increased in placebo-treated infants and decreased in inhaled nitric oxide–treated infants. There were no significant differences between groups in recovery of large-aggregate surfactant or contents of surfactant protein A, surfactant protein B, surfactant protein C, or total protein, normalized to phospholipid. CONCLUSIONS. We conclude that inhaled nitric oxide treatment for premature infants at risk of bronchopulmonary dysplasia does not alter surfactant recovery or protein composition and may improve surfactant function transiently.

Inflammatory markers and mediators in tracheal fluid of premature infants treated with inhaled nitric oxide.

OBJECTIVE. We compared serial measurements of inflammatory mediators and markers in infants treated with inhaled nitric oxide or placebo to assess the effects of inhaled nitric oxide therapy on lung inflammation during bronchopulmonary dysplasia. We investigated relationships between respiratory severity scores and airway concentrations of inflammatory markers/mediators. METHODS. As part of the Nitric Oxide (to Prevent) Chronic Lung Disease trial, a subset of 99 infants (52 placebo-treated infants and 47 inhaled nitric oxide-treated infants; well matched at baseline) had tracheal aspirate fluid collected at baseline, at 2 to 4 days, and then weekly while still intubated during study gas treatment (minimum of 24 days). Fluid was assessed for interleukin-1β, interleukin-8, transforming growth factor-β, N-acetylglucosaminidase, 8-epi-prostaglandin F2α, and hyaluronan. Results were normalized to total protein and secretory component of immunoglobulin A. RESULTS. At baseline, there was substantial variability of each measured substance and no correlation between tracheal aspirate fluid levels of any substance and respiratory severity scores. Inhaled nitric oxide administration did not result in any time-matched significant change for any of the analytes, compared with the placebo-treated group. There was no correlation between any of the measured markers/mediators and respiratory severity scores throughout the 24 days of study gas administration. In the posthoc analysis of data for inhaled nitric oxide-treated infants, there was a difference at baseline in 8-epi-prostaglandin F2α levels for infants who did (n = 21) and did not (n = 26) develop bronchopulmonary dysplasia at postmenstrual age of 36 weeks. CONCLUSIONS. Inhaled nitric oxide, as administered in this study, seemed to be safe. Its use was not associated with any increase in airway inflammatory substances.

Attenuated interleukin-8/leukocyte immunoresponse in preterm infants compared with term infants hospitalized with respiratory syncytial virus bronchiolitis: a pilot study.

Decreased transplacental transfer of antibodies and altered immunoresponsiveness may place preterm (PT) infants at higher risk for serious consequences from respiratory syncytial virus (RSV) bronchiolitis. We hypothesize that among infants hospitalized with RSV bronchiolitis, immune response in PT infants may be different when compared with that of term infants. Nasal-wash samples were collected from 11 PT (<37 weeks of gestation) and 13 term infants (≥37 weeks of gestation) hospitalized with RSV bronchiolitis. Severity of illness (clinical score [CS]), admission peripheral oxygen saturation, and days subjects required supplemental oxygen were compared. Nasal-wash leukocyte count as well as cytokines for interleukin (IL)-8, IL-4, and interferon-γ (IFN-γ) were assayed. No significant differences in CS, admission SaO(2), and O(2) days were seen between PT and term infants. Nasal-wash leukocyte counts and IL-8 levels were higher in term infants compared with PT and correlated with severity (higher CS) in term (p < 0.05) but not in PT (p > 0.05) infants. IL-4 and IFN-γ levels did not differ between the 2 groups (p > 0.05). PT infants hospitalized with RSV bronchiolitis have lower nasal-wash leukocyte counts and a less robust IL-8 response than term infants, and only in term infants did IL-8 levels correlate with clinical disease severity.

Differences in perspective on prognosis and treatment of children with trisomy 18.

Differences in perspective between physicians caring for children with trisomy 18 may be confusing and stressful for parents. The hypothesis of this study was that neonatologists and pediatric pulmonologists differ in their opinions regarding long‐term prognosis and recommended interventions. Neonatologists and pediatric pulmonologists in New York State were surveyed. Respondents were asked to report their personal experience caring for affected children, opinions on prognosis, major influences on their opinions, and their likelihood of recommending specific medical or surgical interventions for two clinical vignettes. A total of 393 surveys were mailed, 327 to neonatologists and 66 to pediatric pulmonologists. Sixty‐six (20%) neonatologists and 21 (32%) pediatric pulmonologists completed the survey. Neonatologists had cared for more patients with trisomy 18. Twenty‐nine percent of pediatric pulmonologists had never cared for a patient with trisomy 18 compared to 2% of neonatologists, P < 0.001. Pediatric pulmonologists were more likely to recommend almost all interventions including antibiotics for pneumonia, mechanical ventilation, cardiac and orthopedic surgery, and “full code resuscitation.” Neonatologists were more likely to recommend comfort care only or palliative care. Fifty‐four percent of neonatologists and 5% of pediatric pulmonologists thought patients with trisomy 18 without significant congenital heart disease would die before age one despite aggressive medical care, P < 0.001. The major influences impacting these recommendations also varied. Pediatric pulmonologists are more optimistic about the prognosis for children than neonatologists and more likely to recommend medical and surgical interventions. Experience with the condition and perception of survivability may contribute to these differences in approach.

Are placental Fas and Fas ligand gene polymorphisms associated with preeclampsia

INTRODUCTION Increased placental trophoblastic apoptosis has been reported in pregnancies complicated by preeclampsia. Fas-Fas ligand is one of the major signal transduction pathways of apoptosis. OBJECTIVES To determine if placental Fas and Fas ligand gene polymorphisms differ between patients with and without preeclampsia. METHODS Forty-five singleton placentas were studied. Twenty-three placentas were from preeclamptic pregnancies and 22 were from normotensive controls. The study was approved by IRB. Genotyping was performed for Fas-1377, Fas-691, Fas-670, Fas ligand-844, Fas ligand-1174, Fas ligand-2777. Chi-square and Fishers exact tests were used for statistical analysis. RESULTS There were no significant differences in maternal age, parity or race between the two groups. There were no significant differences in genotypes or allele frequencies for the placental Fas-1377, Fas-691, Fas-670, Fas ligand-844, Fas ligand-1174 and Fas ligand-2777. CONCLUSION Immune intolerance of maternal and placental interaction plays an important role in the pathogenesis of preeclampsia. Our findings do not support the role of placental Fas and Fas ligand gene polymorphisms in the pathogenesis of preeclampsia. The heterogeneous and complex etiology of preeclampsia makes it unrealistic to expect a single nucleotide polymorphism to explain the pathogenesis of this pregnancy complication. This relatively understudied area warrants further investigation.

PP128. Placental Caspase-3 gene polymorphisms is associated with preeclampsia

INTRODUCTION Increased placental trophoblastic apoptosis (programmed cell death) was previously reported in pregnancies complicated by preeclampsia. Caspase-3 is one of the key executioners of apoptosis. Caspase are expressed in many tissues including human placental trophoblast and other tissues. Variations in the promoter area of the Caspase genes may modulate apoptotic signaling, contributing to an increased risk of preeclampsia OBJECTIVES To determine if gene polymorphisms of Caspase 3 proteins differ between patient with and without preeclampsia. METHODS Forty-three singleton placentas were studied. Twenty-two placentas were with preeclampsia and 21 were normotensive controls. DNA was extracted from placentas using QIAAmp DNA Minikit. Genotyping of Caspase 3 +567 was determined by real-time PCR using the Applied Biosystems Prism 7900 HT SDS machine. Chi-square and Fishers exact tests were used for statistical analysis. RESULTS There were no significant differences in maternal age, parity or race between the two groups. Preeclamptic placentas had higher frequency of wild type TT of Caspase-3 SNP (+567) as compared with normotensive controls (59% versus 28.5%). Preeclamptic placentas expressed significantly more genotype of TT of Caspase-3 SNP (+567) than normotensive patients when compared to CC (p=0.02). The alle frequencies of the Caspase SNP (+567) in preeclampstic placentas were 0.77 and 0.23 for T and C, respectively, as compared to 0.52 and 0.48, respectively, in placentas from normotensive pregnancies. CONCLUSION Immune intolerance of maternal and placental interaction plays an important role in the pathogenesis of preeclampsia. Increased of placental apoptosis was reported in pregnancy complicated with preeclamsia. Our findings indicate placental Caspase 3 (+567) gene polymorphisms is associated with preeclampsia. Altered placental alle frequencies and caspase-3 SNP (+567) in preeclampsia further suggests preeclampsia is a trophoblastic disorder.

Does surfactant type cause a differential proinflammatory response in preterm infants with respiratory distress syndrome

IntroductionThe objective of this study was to compare the pulmonary inflammatory response of premature infants with respiratory distress following instillation of one of two commonly available surfactant preparations.MethodsThis was a prospective, randomized investigation of preterm infants who were less than 30 weeks of gestational age, weighed less than 1 kg at birth, and who qualified to receive surfactant. Infants with multiple congenital anomalies or whose mothers were taking anti-inflammatory medications were ineligible. Tracheal aspirates (TAs) were collected on days 1, 3, 5, and 7 and airway cytokines from TAs were assayed for interleukin (IL)-8 and IL-6.ResultsInfants were evenly matched by gestation (26±2 days and 26±1 days [mean±SD], Surfactant A and B, respectively) and birth weight (730±141 g and 732±167 g). TA cytokine levels were not different between or within groups. Ventilator requirements and clinical outcomes were similar between the two groups.ConclusionThe postnatal airway inflammatory response observed in preterm infants is not altered by the instillation of either surfactant preparation.