Reconstructed mass-spectrometric pattern for characterization of carbon compounds in smoker’s lung in situ

Abstract

Cigarette smoke is a major anthropogenic pollutant and contributes to the permanent load of ambient particulate matter in the air, particularly indoors. It is the leading risk factor for premature loss of life due to chronic bronchitis, emphysema and lung cancer. Smoker's lung and graphite pneumoconiosis are pathological states characterized by the deposition of carbonaceous particles. Mass spectrometry was used to evaluate unstained lung sections obtained in vivo from a heavy smoker and a patient with occupationally acquired graphite pneumoconiosis. The composition of carbon compounds deposited in lung tissue samples is demonstrated here for the first time. Thirty carbonaceous-containing microareas from ten biopsies (three areas per biopsy) of lung tissues were analyzed mass-spectrometrically. In each case, the samples were taken from a smoker's lung or those demonstrating a graphite pneumoconiosis. The lung-tissue samples were selected by light microscopy before they were evaporated for mass spectrometry. First-order criteria were anionic and cationic mass peaks which occur within the mass patterns in lung tissues of smoker's lung, although not in graphite pneumoconiosis. Second-order criteria were mass peaks from smoker's lung with standard deviations SD < or = 14% of the mean value. First and second-order mass peaks matched the mass peaks of experimental cigarette-smoke condensate in 9 out of 11 peaks. A software program was developed that enabled fast, automated recognition of the typical mass peaks, and thereby confirmed the histological diagnosis of smoker's lung. The analysis of carbonaceous particles within lung biopsies from a heavy smoker corresponded to the spectra of tobacco condensate and not to the investigated biopsies of graphite peneumoconiosis. The analyses were performed in order to find out whether mass-spectrometric criteria exist for the differentiation of carbonaceous lung-tissue deposits. Mass spectrometry may be a valuable tool in determining the composition of carbon compounds deposited in human lung tissue. So far, qualitative assessment of the composition of deposits in lung tissue is only possible after the patient is deceased (autopsy).