No abstract

Oxidative stress is believed to play an important role in the pathogenesis of smoking-induced chronic obstructive pulmonary disease. We hypothesized that polymorphisms of antioxidant genes glutathione S-transferase M1 (GSTM1), GSTT1, GSTP1, and heme oxygenase-1 (HMOX1) would be associated with susceptibility to accelerated decline of lung function in smokers. We genotyped 621 subjects (299 rapid decliners [change in forced expiratory volume in 1 second (DeltaFEV(1)) = -152 +/- 2.5 ml/year] and 322 nondecliners [DeltaFEV(1) = +15 +/- 1.5 ml/year]) selected from among smokers followed for 5 years in the National Heart, Lung, and Blood Institute Lung Health Study. Because genotype frequencies were different between ethnic groups, we limited the association study to 594 whites (286 rapid decliners and 308 nondecliners). None of the genotypes studied had a statistically significant effect on decline of lung function when analyzed separately. There was an association between rapid decline of lung function and presence of all three GST polymorphisms (odds ratio [OR] = 2.83; p = 0.03). A combination of a family history of chronic obstructive pulmonary disease with GSTP1 105Ile/Ile genotype was also associated with rapid decline of lung function (OR = 2.20; p = 0.01). However, due to the multiple comparisons that were made, these associations may represent type 1 error. There was no association between HMOX1 (GT)n alleles and the rate of decline in lung function in smokers.

Background: Stroke is accompanied by a distinguished inflammatory reaction that is initiated by the infiltration of immunocytes, expression of cytokines, and other inflammatory mediators. As natural killer cells (NK cells) are a type of cytotoxic lymphocyte critical to the innate immune system, we investigated the mechanism of NK cells-induced brain injuries after cerebral ischemia and the chemotactic effect of IP-10 simultaneously. Methods: NK cells infiltration, interferon-gamma (IFN-γ) and IP-10 expression were detected by immunohistochemistry, immunofluorescence, PCR and flow cytometry in human and C57/BL6 wild type mouse ischemic brain tissues. The ischemia area was detected via 2,3,5-triphenyltetrazolium chloride staining. CXCR3 mean fluorescence intensity of isolated NK cells was measured by flow cytometry. The neuronal injury made by NK cells was examined via apoptosis experiment. The chemotactic of IP-10 was detected by migration and permeability assays. Results: In human ischemic brain tissue, infiltrations of NK cells were observed and reached a peak at 2 to 5 days. In a permanent middle cerebral artery occlusion (pMCAO) model, infiltration of NK cells into the ischemic infarct region reached their highest levels 12 hours after ischemia. IFN-γ-positive NK cells and levels of the chemokine IP-10 were also detected within the ischemic region, from 6 hours up to 4 days after pMCAO was performed, and IFN-γ levels decreased after NK cells depletion in vivo. Co-culture experiments of neural cells with NK cells also showed that neural necrosis was induced via IFN-γ. In parallel experiments with IP-10, the presence of CXCR3 indicates that NK cells were affected by IP-10 via CXCR3, and the effect was dose-dependent. After IP-10 depletion in vivo, NK cells decreased. In migration assays and permeability experiments, disintegration of the blood-brain barrier (BBB) was observed following the addition of NK cells. Moreover, in the presence of IP-10 this injury was aggravated. Conclusions: All findings support the hypothesis that NK cells participate in cerebral ischemia and promote neural cells necrosis via IFN-γ. Moreover, IP-10 intensifies injury to the BBB by NK cells via CXCR3.