Nuclear factor-kappaB (NF-B) plays a central role in regulating key proinflammatory mediators. The activation of NF-B is increased in tracheal aspirate (TA) cells from premature infants developing bronchopulmonary dysplasia (BPD). We studied the effect of azithromycin (AZM) on the suppression of NF-B activation and the synthesis of pro-inflammatory cytokines IL-6 and IL-8 by TA cells obtained from premature infants. Tracheal aspirate cells were stimulated with tumor necrosis factor-alpha (TNF-␣) and incubated with AZM. The nuclear NF-B-DNA binding activity, the levels of inhibitory kappaB-alpha (IB-␣) in the cytoplasmic fraction and IL-6 and IL-8 release in the cell culture media were measured. Stimulation of TA cells by TNF-␣ increased the activation of NF-B, which was suppressed by the addition of AZM. Increased activation of NF-B was also associated with increased levels of pro-inflammatory cytokines (IL-6 and IL-8). AZM significantly reduced the IL-6 and IL-8 production to the levels similar to control. TNF-␣ stimulation also increased the degradation of IB-␣, which was restored with the addition of AZM. Our data suggest that AZM therapy may be an effective alternative to steroids in reducing lung inflammation and prevention of BPD in ventilated premature infants. (Pediatr Res 62: [483][484][485][486][487][488] 2007)

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The inherited leukodystrophy Canavan disease arises due to a loss of the ability to catabolize N-acetylaspartic acid (NAA) in the brain and constitutes a major point of focus for efforts to define NAA function. Accumulation of noncatabolized NAA is diagnostic for Canavan disease, but contrasts with the abnormally low NAA associated with compromised neuronal integrity in a broad spectrum of other clinical conditions. Experimental evidence for NAA function supports a role in white matter lipid synthesis, but does not explain how both elevated and lowered NAA can be associated with pathology in the brain. We have undertaken a systematic analysis of postnatal development in a mouse model of Canavan disease that delineates development and pathology by identifying markers of oxidative stress preceding oligodendrocyte loss and dysmyelination. These data suggest a role for NAA in the maintenance of metabolic integrity in oligodendrocytes that may be of relevance to the strong association between NAA and neuronal viability. N-acetylaspartic acid is proposed here to support lipid synthesis and energy metabolism via the provision of substrate for both cellular processes during early postnatal development.

Objectives: To study the association between angiopoietin 2 (Ang2) concentrations in tracheal aspirates (TAs) and adverse outcome (bronchopulmonary dysplasia (BPD)/death) in ventilated premature infants (VPIs) and modulation of Ang2 concentrations with dexamethasone (Dex) use.Study Design: Serial TA samples were collected on days 1, 3, 5 and 7, and Ang2 concentrations were measured. Ang2 TA concentrations were compared prior to and after 48 to 72 h of using Dex.Result: A total of 151 TA samples were collected from 60 VPIs. BPD was defined as the oxygen requirement at 36 weeks postmenstrual age (PMA). Twelve infants (mean ± s.d.) (gestational age (GA) 26.5 ± 2.1 weeks, birth weight (BW) 913±230 g) had no BPD, 32 infants (GA 25.8±1.4 weeks, BW 768 ± 157 g) developed BPD and 16 infants (GA 24.5 ± 1.1 weeks, BW 710 ± 143 g) died before 36 weeks PMA. Ang2 concentrations were significantly lower in infants with no BPD (median, 25th and 75th percentile) (157, 16 and 218 pg mg À1 ) compared with those who developed BPD (234, 138 and 338 pg mg À1 , P ¼ 0.03) or BPD and/or death (234, 157 and 347 pg mg À1 , P ¼ 0.017), in the first week of life. Twenty-six VPIs (BW 719±136 g, GA 25.1±1.3 weeks) received 27 courses of Dex. Ang2 concentrations before starting Dex were 202, 137 and 278 pg mg À1 and significantly decreased to 144, 0 and 224 pg mg À1 after therapy (P ¼ 0.007).Conclusions: Higher Ang2 concentrations in TAs are associated with the development of BPD or death in VPIs. Dex use suppressed Ang2 concentrations.

Nuclear Factor-kappaB (NF-kappaB) plays a central role in regulating the key mediators of inflammation involved in acute lung injury. The anti-inflammatory effect of steroids by suppressing pro-inflammatory cytokines may be mediated by inhibition of transcription factor NF-kappaB. The objective of this study was to determine the effect of glucocorticoid therapy on the expression of NF-kappaB in the cells of tracheobronchial lavage fluid (TBLF) in premature neonates with respiratory distress. Nineteen premature neonates requiring mechanical ventilation and receiving glucocorticoids were enrolled. Their gestational age (mean +/- SD) was 25.0 +/- 1.2 wk, birth weight 714 +/- 105 g and age of starting dexamethasone was 33 +/- 15 d. Tracheobronchial lavage fluid was collected before and 48-72 h after starting dexamethasone. NF-kappaB expression was measured by immunocytochemistry using mouse MAb against the p65 subunit of NF-kappaB on cytospin slides. The percent of cells stained and the intensity staining index were significantly higher before starting dexamethasone compared with after steroid therapy. Localization of NF-kappaB was significantly decreased in the cytoplasm and nuclei of mononuclear cells after initiation of dexamethasone therapy. The concentration of IL-8 was also significantly lower after starting dexamethasone. In conclusion, dexamethasone suppressed the expression of NF-kappaB in the cytoplasm and nuclei of mononuclear cells and decreased levels of IL-8 in TBLF from premature neonates with respiratory distress. The anti-inflammatory effects of corticosteroids may be mediated through NF-kappaB.