Cigarette Smoke-induced Lung Damage Research Articles

Paclobutrazol ameliorates cigarette smoke-induced chronic obstructive pulmonary disease (COPD) in experimental rats

BackgroundThe cigarette smoking epidemic is one of the desperate threats experienced all over the world. Cigarettes cause diseases such as chronic obstructive pulmonary disease (COPD), asthma, lung cancer, stroke, heart diseases, etc. Paclobutrazol is a growth regulator hormone that increases antioxidant enzymes, mineral absorption, carbohydrate synthesis, and flowering and fruit production in plants. ObjectiveIn the current study, we assessed the ameliorative effect of paclobutrazol against chronic cigarette smoke-induced COPD in rats. MethodologyA side-stream cigarette exposure rat model was used for the study, which is a well-accepted model to evaluate cigarette smoke-induced lung damage. The paclobutrazol treatment was given for 12 weeks, and since the reduction in body weight is the primary symptom of COPD, the food efficiency and the weight gain were measured. Muscular strength was analyzed with a grip strength test, and respiratory functions were assessed with a whole-body plethysmograph. Plasma leptin was measured to detect the fat mass index. C-reactive protein was quantified to assess the level of inflammation. Further bronchoaleveolar fluid was collected and analyzed for the total white blood cell count, neutrophils, lymphocytes, and monocytes to evaluate the inflammation. In order to confirm the anti-inflammatory property of paclobutrazol against cigarette smoke-induced lung inflammation, histopathological analysis of lung tissue was done. ResultsThe paclobutrazol treatment increased the body weight, improved respiratory functions, and decreased inflammation in the rats exposed to secondhand cigarette smoke. Our results of histopathological analysis confirm that paclobutrazol has effectively inhibited cigarette smoke-induced lung tissue damage in young Wistrar rats. ConclusionHence, it can be used as a supplementary drug to protect smokers from cigarette smoke-induced lung damage.

Directed Differentiation of Human-Induced Pluripotent Stem Cells to Mesenchymal Stem Cells.

Multipotent stromal cells, also known as mesenchymal stem cells (MSCs), possess great potential to generate a wide range of cell types including endothelial cells, smooth muscle cells, bone, cartilage, and lipid cells. This protocol describes in detail how to perform highly efficient, lineage-specific differentiation of human-induced pluripotent stem cells (iPSCs) with an MSCs fate. The approach uses a clinically compliant protocol with chemically defined media, feeder-free conditions, and a CD105 positive and CD24 negative selection to achieve a single cell-based MSCs derivation from differentiating human pluripotent cells in approximately 20 days. Cells generated with this protocol express typical MSCs surface markers and undergo adipogenesis, osteogenesis, and chondrogenesis similar to adult bone marrow-derived MSCs (BM-MSCs). Nonetheless, compared with adult BM-MSCs, iPSC-MSCs display a higher proliferative capacity, up to 120 passages, without obvious loss of self-renewal potential and constitutively express MSCs surface antigens. MSCs generated with this protocol have numerous applications, including expansion to large scale cell numbers for tissue engineering and the development of cellular therapeutics. This approach has been used to rescue limb ischemia, allergic disorders, and cigarette smoke-induced lung damage and to model mesenchymal and vascular disorders of Hutchinson-Gilford progeria syndrome (HGPS).

NTPDase1/CD39 and aberrant purinergic signalling in the pathogenesis of COPD.

Purinergic receptor activation via extracellular ATP is involved in the pathogenesis of chronic obstructive pulmonary disease (COPD). Nucleoside triphosphate diphosphohydrolase-1/CD39 hydrolyses extracellular ATP and modulates P2 receptor signalling.We aimed to investigate the expression and function of CD39 in the pathogenesis of cigarette smoke-induced lung inflammation in patients and preclinical mouse models. CD39 expression and soluble ATPase activity were quantified in sputum and bronchoalveolar lavage fluid (BALF) cells in nonsmokers, smokers and COPD patients or mice with cigarette smoke-induced lung inflammation. In mice, pulmonary ATP and cytokine concentrations, inflammation and emphysema were analysed in the presence or absence of CD39.Following acute cigarette smoke exposure CD39 was upregulated in BALF cells in smokers with further increases in COPD patients. Acute cigarette smoke exposure induced CD39 upregulation in murine lungs and BALF cells, and ATP degradation was accelerated in airway fluids. CD39 inhibition and deficiency led to augmented lung inflammation; treatment with ATPase during cigarette smoke exposure prevented emphysema.Pulmonary CD39 expression and activity are increased in COPD. CD39 deficiency leads to enhanced emphysema in mice, while external administration of a functional CD39 analogue partially rescues the phenotype. The compensatory upregulation of pulmonary CD39 might serve as a protective mechanism in cigarette smoke-induced lung damage.

Macrophage Migration Inhibitory Factor Is a Novel Determinant of Cigarette Smoke–Induced Lung Damage

Cigarette smoke (CS) is the most common cause of chronic obstructive pulmonary diseases (COPD), including emphysema. CS exposure impacts all cell types within the airways and lung parenchyma, causing alveolar tissue destruction through four mechanisms: (1) oxidative stress; (2) inflammation; (3) protease-induced degradation of the extracellular matrix; and (4) enhanced alveolar epithelial and endothelial cell (EC) apoptosis. Studies in human pulmonary ECs demonstrate that macrophage migration inhibitory factor (MIF) antagonizes CS-induced apoptosis. Here, we used human microvascular ECs, an animal model of emphysema (mice challenged with chronic CS), and patient serum samples to address both the capacity of CS to alter MIF expression and the effects of MIF on disease severity. We demonstrate significantly reduced serum MIF levels in patients with COPD. In the murine model, chronic CS exposure resulted in decreased MIF mRNA and protein expression in the intact lung. MIF deficiency (Mif(-/-)) potentiated the toxicity of CS exposure in vivo via increased apoptosis of ECs, resulting in enhanced CS-induced tissue remodeling. This was linked to MIF's capacity to protect against double-stranded DNA damage and suppress p53 expression. Taken together, MIF appears to antagonize CS-induced toxicity in the lung and resultant emphysematous tissue remodeling by suppressing EC DNA damage and controlling p53-mediated apoptosis, highlighting a critical role of MIF in EC homeostasis within the lung.

Differential function of IL-17A in cigarette smoke induced lung damage

Smoking is the main risk factor for the chronic obstructive pulmonary disease (COPD). A recent study demonstrated by quantitative microcomputed tomography (µCT) that IL-17A-deficient mice exposed to cigarette smoke are protected from increases in lung volume and decreased lung density. This suggests that Th-17/IL-17-dependent immune mechanisms mediate smoke-induced lung damage, such as the development of emphysema. Here, we demonstrate a more complex role of IL-17A in the development of lung damage in mice chronically exposed to smoke. Physiologically relevant pulmonary function showed that IL-17A deficient mice were per se not protected from smoke-induced emphysematous disease. Respiratory compliance was increased in IL-17-deficient mice after smoke exposure, even though IL-17-deficient mice were partially protected from smoke-induced changes in the total lung capacity and hysteresis. Histology and morphometry showed that smoke-exposure results in loss of lung structure in IL-17-deficient mice. These results suggest that, in the present disease model, IL-17A rather has a protective than a deleterious role in smoke-induced loss of lung function.

Differential function of IL-17A in cigarette smoke induced lung damage

Differential function of IL-17A in cigarette smoke induced lung damage

Cellular and molecular mechanisms of cigarette smoke-induced lung damage and prevention by vitamin C.

BackgroundCigarette smoke-induced cellular and molecular mechanisms of lung injury are not clear. Cigarette smoke is a complex mixture containing long-lived radicals, including p-benzosemiquinone that causes oxidative damage. Earlier we had reported that oxidative protein damage is an initial event in smoke-induced lung injury. Considering that p-benzosemiquinone may be a causative factor of lung injury, we have isolated p-benzosemiquinone and compared its pathophysiological effects with cigarette smoke. Since vitamin C is a strong antioxidant, we have also determined the modulatory effect of vitamin C for preventing the pathophysiological events.MethodsVitamin C-restricted guinea pigs were exposed to cigarette smoke (5 cigarettes/day; 2 puffs/cigarette) for 21 days with and without supplementation of 15 mg vitamin C/guinea pig/day. Oxidative damage, apoptosis and lung injury were assessed in vitro, ex vivo in A549 cells as well as in vivo in guinea pigs. Inflammation was measured by neutrophilia in BALF. p-Benzosemiquinone was isolated from freshly prepared aqueous extract of cigarette smoke and characterized by various physico-chemical methods, including mass, NMR and ESR spectroscopy. p-Benzosemiquinone-induced lung damage was examined by intratracheal instillation in guinea pigs. Lung damage was measured by increased air spaces, as evidenced by histology and morphometric analysis. Oxidative protein damage, MMPs, VEGF and VEGFR2 were measured by western blot analysis, and formation of Michael adducts using MALDI-TOF-MS. Apoptosis was evidenced by TUNEL assay, activation of caspase 3, degradation of PARP and increased Bax/Bcl-2 ratio using immunoblot analysis and confocal microscopy.ResultsExposure of guinea pigs to cigarette smoke resulted in progressive protein damage, inflammation, apoptosis and lung injury up to 21 days of the experimental period. Administration of 15 mg of vitamin C/guinea pig/day prevented all these pathophysiological effects. p-Benzosemiquinone mimicked cigarette smoke in causing protein modification and apoptosis in vitro and in A549 cells ex vivo as well as apoptosis and lung damage in vivo. All these pathophysiological events were also prevented by vitamin C.Conclusionp-Benzosemiquinone appears to be a major causative factor of cigarette smoke-induced oxidative protein damage that leads to apoptosis and lung injury. The pathophysiological events are prevented by a moderately large dose of vitamin C.