Breath biomarkers of exposure and disease

Exhaled breath is a non-invasive biological sample that can be collected from humans and animals. Breath analysis can be used to monitor disease activity and to quantify chemical exposure. However, breath molecule concentrations can change as a result of variations in ventilation. A novel breath collection system has been developed to monitor volume flow, carbon dioxide, mouth pressure, and respiratory rate during breath collection. Thermal adsorbents were specially designed for the quantitative capture and release of breath molecules, providing a profile of molecules in breath. The breath samples were analyzed by thermal desorption, capillary gas chromatography and mass spectrometry. Real-time monitors were used to analyze molecules such as carbon monoxide, nitric oxide and sulfur compounds.; Experiments were performed using breath analysis to study mechanisms of disease pathogenesis and to characterize occupational exposure. Breath was sampled from obese and lean mice to investigate the role of obesity in liver disease. Oxidative stress status and novel disease markers were also investigated by sampling from patients in clinics for lung cancer, scleroderma, steatohepatitis and Alzheimer's disease clinics. The objective of these experiments was to see if breath could be developed as a non-invasive sample for identification of sensitive markers of disease status. Breath analysis was also used in an exposure assessment of nurses, who are occupationally exposed to volatile anesthetics while working in the perianesthesia care unit (PACU).; Two compounds were identified that were specific to lung disease. One marker, acetonitrile, was predictive of smoking and dimethyl ether was correlated with chronic obstructive pulmonary disease (COPD). Ethane, a marker of lipid peroxidation, was found to be associated with lung cancer, scleroderma and Alzheimer's disease. Ethanol production was increased in obese mice compared to lean littermates. A human control study indicated that ethanol increases post-prandially, and may be related to eating or gut dismotility. Sulfur-containing compounds also increased with time of day. The exposure assessment showed that nurses bioaccumulate isoflurane over the course of a shift in the PACU and may experience biological effects from exposure. In summary, breath is a valuable but underused matrix for exposure assessment and monitoring biological effects.