Obesity decreases the oxidant stress induced by tobacco smoke in a rat model.

Obesity and emphysema are associated with low-grade systemic inflammation and oxidant stress. Assuming that the oxidant stress induced by emphysema would be decreased by obesity, we analyzed the oxidant/antioxidant state in a rat model combining both diseases simultaneously. Obesity was induced using sucrose, while emphysema by exposure to tobacco smoke. End-points evaluated were: body weight, abdominal fat, plasma dyslipidemia and malondialdehyde (MDA), insulin and glucose AUC, activities of Mn-superoxide dismutase (Mn-SOD), glutathione reductase (GR), glutathione transferase (GST) and glutathione peroxidase (GPx); lung MnSOD and 3-nitrotyrosine (3-NT) immunostaining, and expression of αV and ß6 integrin subunits. In rats with obesity, the body weight, abdominal fat, plasma triglyceride levels, glucose AUC, insulin levels, GST activity, and αV and ß6 integrin expressions were amplified. The rats with emphysema had lower values of body weight, abdominal fat, plasma insulin, triglycerides and glucose AUC but higher values of plasma MDA, GPx activity, and the lung expression of the αV and ß6 integrins. The combination of obesity and emphysema compared to either condition alone led to diminished body weight, abdominal fat, plasma insulin MDA levels, GPx and GST activities, and αV and ß6 integrin expressions; these parameters were all previously increased by obesity. Immunostaining for MnSOD augmented in all experimental groups, but the staining for 3-NT only increased in rats treated with tobacco alone or combined with sucrose. Results showed that obesity reduces oxidant stress and integrin expression, increasing antioxidant enzyme activities; these changes seem to partly contribute to a protective mechanism of obesity against emphysema development.

Overexpression of MEOX2 and TWIST1 is associated with H3K27me3 levels and determines lung cancer chemoresistance and prognosis.

Lung cancer is the leading cause of death from malignant diseases worldwide, with the non-small cell (NSCLC) subtype accounting for the majority of cases. NSCLC is characterized by frequent genomic imbalances and copy number variations (CNVs), but the epigenetic aberrations that are associated with clinical prognosis and therapeutic failure remain not completely identify. In the present study, a total of 55 lung cancer patients were included and we conducted genomic and genetic expression analyses, immunohistochemical protein detection, DNA methylation and chromatin immunoprecipitation assays to obtain genetic and epigenetic profiles associated to prognosis and chemoresponse of NSCLC patients. Finally, siRNA transfection-mediated genetic silencing and cisplatinum cellular cytotoxicity assays in NSCLC cell lines A-427 and INER-37 were assessed to describe chemoresistance mechanisms involved. Our results identified high frequencies of CNVs (66-51% of cases) in the 7p22.3-p21.1 and 7p15.3-p15.2 cytogenetic regions. However, overexpression of genes, such as MEOX2, HDAC9, TWIST1 and AhR, at 7p21.2-p21.1 locus occurred despite the absence of CNVs and little changes in DNA methylation. In contrast, the promoter sequences of MEOX2 and TWIST1 displayed significantly lower/decrease in the repressive histone mark H3K27me3 and increased in the active histone mark H3K4me3 levels. Finally these results correlate with poor survival in NSCLC patients and cellular chemoresistance to oncologic drugs in NSCLC cell lines in a MEOX2 and TWIST1 overexpression dependent-manner. In conclusion, we report for the first time that MEOX2 participates in chemoresistance irrespective of high CNV, but it is significantly dependent upon H3K27me3 enrichment probably associated with aggressiveness and chemotherapy failure in NSCLC patients, however additional clinical studies must be performed to confirm our findings as new probable clinical markers in NSCLC patients.

The effect of obesity and tobacco smoke exposure on inflammatory mediators and matrix metalloproteinases in rat model.

Obesity is characterized by hypertrophy of adipose tissue and chronic obstructive pulmonary disease (COPD) by lung damage; both diseases are associated with systemic low-grade inflammation. There are no animal models combining obesity and COPD; therefore, these diseases were induced simultaneously in rats to analyze their effects on the expression of inflammatory mediators and enzymes involved in lung tissue remodeling. Obesity was induced with sucrose (30%) for 4 months concomitant with tobacco smoke exposure (20 cigarettes/day, 5 days/wk) for the last 2 months. Were evaluated: body weight, abdominal fat, dyslipidemia, glucose tolerance test (GTT), histology, inflammatory mediators with qPCR and enzyme-linked immunosorbent assay, matrix metalloproteinases (MMP-2), MMP-9, MMP-12, TIMP-1 and TIMP-2 through qRT-PCR, and MMP-2 and MMP-9 by gelatin zymography. The rats on a sucrose diet exhibited increased body weight, abdominal fat, triglycerides, GTT, and plasma levels of insulin, adiponectin, leptin, resistin, IL-6, IL-1ß, tumor necrosis factor-α (TNF-α) and IFN-γ, upregulated lung IL-6, IL-1ß, TNF-α and IFN-γ, showing hyperplastic bronchial and alveolar epithelium. The animals exposed to sucrose and tobacco smoke exhibited decreased body weight, abdominal fat and plasma levels of leptin, resistin, IL-1ß and IFN-γ, reducing inflammation but showing emphysematous lesions. Expression of gelatinases and MMP-12 augmented in the rats exposed to tobacco smoke alone or combined with sucrose. Zymography showed prominent gelatinases activity in all the experimental groups. These results suggest that simultaneous exposure to sucrose and tobacco smoke decreases inflammation but results in emphysematous lesions similar to those observed with tobacco smoke exposure, suggesting that obesity does not confer any protective effect against lung damage.

Oxidative stress and lung injury induced by short-term exposure to wood smoke in guinea pigs.

Oxidative stress and lung injury induced by short-term exposure to wood smoke were evaluated in guinea pigs through cell profile, bronchoalveolar lavage (BAL), conventional histology and immunohistochemistry (4-hydroxynonenal, 3-nitrotyrosine, Mn-superoxide dismutase, heme oxygenase-1); malondialdehyde and 4-hydroxynonenal concentration, Mn-superoxide dismutase, glutathione reductase, glutathione peroxidase, and catalase activities in plasma, lung and BAL. Total cells increased in BAL, and the percentage of macrophages, neutrophils and lymphocytes augmented (72-96 h). Histopathological examination of lung tissues showed mild thickening of membranous bronchiole walls, infiltration of foamy macrophages and polymorphonuclear leukocytes in bronchial, bronchiolar and intraalveolar spaces. Goblet cell hyperplasia was also observed in bronchial and bronchiolar epithelia. Plasma malondialdehyde concentration was increased at all times, while 4-hydroxynonenal was increased only in plasma and BAL after 24 h. Plasma glutathione reductase activity increased at 24 and 72 h, BAL glutathione peroxidase activity decreased at 72 and 96 h, whereas catalase activity increased in plasma at 72 h, and decreased in BAL at 24 h. Immunostaining intensity to 4-hydroxynonenal, 3-nitrotyrosine, Mn-superoxide dismutase and heme oxygenase-1 was enhanced mainly in macrophages, bronchial/bronchiolar epithelial cells and type II pneumocytes after 72-96 h of wood smoke exposure. Overall, short-term exposure to wood smoke induces alterations in oxidative/antioxidant state in lung and airway injury, similar to those observed in humans with domestic exposure.