DNA single- and double-strand breaks by alkaline- and immuno-comet assay in lymphocytes of workers exposed to styrene.

Occupational exposure to styrene was studied in 34 workers employed in the production of fiberglass-reinforced plastic sheets and compared to 29 unexposed healthy controls. We evaluated genotoxic effects induced by occupational styrene exposure in lymphocytes by alkaline version of the comet assay to detect single-strand breaks (SSBs), DNA oxidation products (formamido pyrimidine glycosilase (Fpg)- and endonuclease (Endo III)-sensitive sites) and DNA repair kinetics studies, as well as the neutral version of comet assay for DNA double-strand breaks (DSBs). An innovative aspect of this study was the use of immuno-comet assay, a new technique that recognizes DSBs with specific antibody by DAPI/FITC method. The battery of parameters included markers of external and internal exposure. Exposed workers showed significant high levels of SSBs (p<0.0001) and DSBs (p<0.0001) in neutral- and immuno-comet assay. A drastic decrease in DNA repair activity as compared to controls was observed (180 min vs. 35 min). Styrene workplace concentration significantly correlated with alkaline comet parameters (TM, p=0.013; TI, p=0.008), in negative with TL (p=0.022), and with DNA-base oxidation (TM Endo III, p=0.048 and TI Endo III, p=0.028). There was a significant negative correlation between urinary metabolites (MA+PGA) and TM Endo III (p=0.032) and TI Endo III (p=0.017).

Reduced production of anti-inflammatory soluble HLA-G molecules in styrene exposed workers.

HLA-G antigens are non-classical HLA-class I anti-inflammatory molecules. Since styrene exposure has been suggested to induce immune alteration, we analyzed plasma levels and "in vitro" peripheral blood mononuclear cell (PBMC) production of soluble HLA-G (sHLA-G) and interleukin-10 (IL-10) molecules after lipopolysaccharide (LPS) stimulation, in styrene exposed workers and healthy subjects. Exposed workers showed reduced plasma levels of sHLA-G and IL-10 in comparison to healthy controls. Similarly, lower levels of sHLA-G and IL-10 molecules were observed in PBMC culture supernatants after LPS activation. These data propose styrene exposure as a mediator of impaired sHLA-G production.

Decreased heme-oxygenase (HO)-1 in the macrophages of non-small cell lung cancer.

Reactive oxygen species (ROS) are important in the initiation and promotion of cells to neoplastic growth. Heme-oxygenase (HO)-1, the inducible form of heme-oxygenase, is a cytoprotective enzyme that plays a central role in the defence against oxidative stress and is implicated in the protection of lung tissue against exogenous oxidant exposure. We investigated whether the expression of HO-1 would be decreased in lung tumour as compared with tumour-free adjacent lung tissues. HO-1 expression was quantified by immunohistochemistry in tumour macrophages, in macrophages of tumour-free lung and in tumour cells of surgical specimens collected from 53 individuals with surgically resectable non-small cell lung cancer (NSCLC). The expression of HO-1 was decreased in tumour as compared with tumour-free lung macrophages. No correlations were observed between the expression of HO-1 and both the clinicopathological characteristics and the overall survival of the examined subjects. In conclusion, our data show that macrophages of non-small cell lung cancer exhibit impaired anti-oxidant defence mechanisms, likely mediated by HO-1. Conversely, HO-1 expression does not seem to be associated with lung tumour progression and prognosis.

Asthma induced by isocyanates: a model of IgE-independent asthma.

Developments in the understanding of causes and natural history of asthma induced by isocyanates may allow improved preventive strategies for occupational asthma (OA), and may also lead to improved understanding of mechanisms involved in IgE-independent nonoccupational asthma. Studies of genetic markers in OA induced by isocyanates suggest that HLA class II genes, glutathione S-transferase and NAT1 genotypes may predispose to development of this type of OA. Specific IgE antibodies against isocyanates are not always found in subjects with OA caused by isocyanates, leading most researchers to consider this type of OA, as a model of IgE-independent asthma. Evidence for cell-mediated immunity in OA induced by isocyanates has been provided by bronchoalveolar lavage, bronchial biopsy and induced sputum studies. The pathology of this type of asthma is similar to that of nonoccupational asthma, with cells such as eosinophils and T lymphocytes that exhibit signs of activation, and with thickening of the reticular layer of the basement membrane. Animal studies have shown that isocyanate asthma is driven primarily by CD4+ T cells and is dependent upon the expression of Th2 cytokines. However, animal models are not always reflective of human responses. OA induced by isocyanates similarly to nonoccupational asthma, is a multifactorial condition, and it is likely that complex gene-environment interactions play a role. Better understanding of these interactions is important for affected workers, and also has potential relevance for nonoccupational asthma.

Sputum substance P and neurokinin A are reduced during exacerbations of chronic obstructive pulmonary disease.

Involvement of tachykinins in airway inflammation has been demonstrated in animal models, but evidence in humans is sparse. The aim of this study was to quantify the levels of substance P and neurokinin A in induced sputum of patients with chronic obstructive pulmonary disease (COPD) and to compare them with the levels in smokers with normal lung function and healthy nonsmokers. Content of tackykinins was measured in 12 sputum samples collected during stable condition and nine sputum samples collected during exacerbations from 13 COPD patients, in eight sputum samples from smokers with normal lung function and in nine from healthy nonsmokers. Patients with COPD exacerbations had a lower sputum content of substance P compared with the other 3 groups (p<0.05). No differences were found between patients with stable COPD, smokers with normal lung function, and nonsmokers. Sputum levels of neurokinin A were trending in the same direction of substance P, but the significant difference was reached for the paired sputum samples collected from the same COPD patients (n=8) during exacerbation and in stable condition. COPD exacerbations are associated with a reduced sputum content of substance P and neurokinin A. These tackykinins might be involved in COPD exacerbations.