Carlos E Girod | PubMed Health

PubMed2005

COPD: a dust-induced disease?

Various reports have demonstrated the importance of small airway inflammation in the development of airflow limitation and progression of COPD. This hypothesis proposes that the pathogenesis of COPD mirrors a chronic inhalational dust-induced disease. The putative inorganic dust in cigarette smoke is aluminum silicate or kaolinite, a common component of clay soils. Kaolinite has been recovered in the alveolar macrophages of smokers and has been reported as a constituent of tobacco products. The origin of kaolinite in tobacco products remains unknown, and possible potential sources are proposed. On inhalation, kaolinite deposition in the distal lung may promote macrophage accumulation within the terminal airways leading to a respiratory bronchiolitis. In the susceptible smoker, important genetic, environmental, immunologic, and mechanical factors interact and modulate this small airway inflammation, ultimately leading to the pathologic lesion of emphysema. Further studies into the effects of kaolinite on macrophage function and the subsequent development of respiratory bronchiolitis could lead to prevention of COPD at its precursor lesion.

Bronchiolitis↗

PubMed2004

Pulmonary prostacyclin synthase overexpression chemoprevents tobacco smoke lung carcinogenesis in mice.

Increased pulmonary production of prostaglandin I2 (prostacyclin) by lung-specific overexpression of prostacyclin synthase decreases lung tumor incidence and multiplicity in chemically induced murine lung cancer models. We hypothesized that pulmonary prostacyclin synthase overexpression would prevent lung carcinogenesis in tobacco-smoke exposed mice. Murine exposure to tobacco smoke is an established model of inducing pulmonary adenocarcinomas and allows for the testing of potential chemopreventive strategies. Transgenic FVB/N mice with lung-specific prostacyclin synthase overexpression were exposed to mainstream cigarette smoke for 22 weeks and then held unexposed for an additional 20 weeks. All of the exposed animals developed bronchiolitis analogous to the respiratory bronchiolitis seen in human smokers. The transgenic mice, when compared with smoke-exposed transgene negative littermates, had significant decreases in tumor incidence and multiplicity. Significantly fewer transgenics (6 of 15; 40%) developed tumors compared with the tumor incidence in wild-type littermates (16 of 19; 84%; Fisher's exact test, P = 0.012). Tumor multiplicity was also significantly decreased in the transgenic animals (tg+ = 0.4 +/- 0.5 versus wild-type = 1.2 +/- 0.86 tumors/mouse; P < 0.001). Targeted prostaglandin levels at the time of sacrifice revealed significantly elevated prostaglandin I2 levels in the transgenic animals, coupled with significantly decreased prostaglandin E2 levels. Gene expression analysis of isolated type II pneumocytes suggests potential explanations for the observed chemoprevention, with Western blot analysis confirming decreased expression of cytochrome p450 2e1. These studies extend our previous studies and demonstrate that manipulation of prostaglandin production distal to cyclooxygenase significantly reduces lung carcinogenesis in a tobacco smoke exposure model, and gene expression studies show critical alterations in antioxidation, immune response, and cytokine pathways.

Animals↗

PubMed2003

Blue rubber bleb nevus syndrome: endobronchial involvement presenting as chronic cough.

This case report describes a rare presentation of chronic cough secondary to endobronchial involvement with blue rubber bleb nevus syndrome (BRBNS) lesions. BRNBS is a rare syndrome characterized with cavernous hemangiomas involving the skin and GI tract. We report the case of a 37-year-old woman, with known BRBNS, who acquired an intractable cough with a radiograph revealing multiple pulmonary nodules. A bronchoscopy demonstrated various bluish, raised, and hypervascular lesions characteristic for BRBNS involving the right mainstem bronchus and segmental bronchi. To our knowledge, this is the first report of endobronchial involvement with BRBNS.

Adult↗