Linked Life Data

9490660

Source:http://linkedlifedata.com/resource/pubmed/id/9490660

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1998-3-31
pubmed:abstractText
Inhaled nitric oxide (NO) is an important new therapeutic agent used to treat pulmonary arterial hypertension in a variety of disease states. However, the effects of NO on cells in the lung are uncertain. Previously, we have shown that NO gas depresses neutrophil oxidative cell function and increases neutrophil cell death. The purpose of this in vitro study was to determine the mechanism of neutrophil death. We hypothesized that NO hastened cell death by inducing apoptosis. To mimic the clinical environment of patients with respiratory failure, we also studied the effects of hyperoxia on neutrophil cell viability and apoptosis. Isolated human neutrophils were exposed to 80% O2 (O2), NO at 20 ppm in room air (NO/RA), 20 ppm NO blended with 80% O2 (NO/O2), or RA alone (control) for 2 to 24 h. Experiments were repeated with NO concentrations of 5 and 50 ppm and with 20 ppm in the presence of superoxide dismutase (SOD). Neutrophils were also incubated in the absence or presence of neutrophil stimulant fMLP (10 nM). Neutrophil cell viability was measured by fluorescence viability/cytotoxicity assay. Neutrophil apoptosis was assessed by cell death detection ELISA for histone-associated DNA fragments, TdT transferase-mediated fluorescence-labeled dUTP nick end labeling (TUNEL) assay, and DNA fragmentation gel electrophoresis. NO/O2-exposed neutrophils showed decreased viability at 2 h (31.7 +/- 3.7%, mean % viability +/- SD) compared with control (94.7 +/- 4.7%), O2 (75.6 +/- 9.3%), and NO/RA (62.8 +/- 14.9%; P < 0.05 by ANOVA; n = 9). Although control neutrophils demonstrated marked apoptosis at 24 h, there was no significant apoptosis at 2, 4, or 6 h (P < 0.001 by Kruskal-Wallis, n = 20) as assessed by ELISA and TUNEL assays. When compared with RA controls at 2 h, neutrophils exposed to NO/O2 showed significantly more apoptosis (292% of control, range: 106 to 2,488%, P < 0.001 by ANOVA and Kruskal-Wallis) but not with exposure to NO/RA or O2 alone. These findings were confirmed by TUNEL assay (n = 4, P < 0.05). NO/ RA and NO/O2-exposed neutrophils demonstrated both evidence of necrosis and enhanced DNA fragmentation at 2 h by gel electrophoresis (n = 2). Fifty parts per million NO produced similar findings, but exposure to 5 ppm NO did not induce significant DNA fragmentation. Coincubation with SOD inhibited NO/ O2-associated apoptosis, suggesting peroxynitrite contributed to cell death. Stimulation with fMLP did not alter apoptosis induced in neutrophils exposed to NO/RA or NO/O2. We conclude that exogenous NO gas, at clinically relevant concentrations under hyperoxic conditions, induces cell death in neutrophils in part by enhancing DNA fragmentation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
1044-1549
pubmed:author
pubmed:issnType
Print
pubmed:volume
18
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
421-8
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Exogenous nitric oxide enhances neutrophil cell death and DNA fragmentation.
pubmed:affiliation
Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't