Factors modulating the epithelial response to toxicants in tracheobronchial airways

As one of the principal interfaces between the organism and the environment , the respiratory system is a target for a wide variety of toxicants and ca rcinogens. The cellular and architectural complexity of the respiratory sys tem appears to play a major role in defining the focal nature of the pulmon ary response to environmental stressors. This review will address the biolo gical factors that modulate the response of one of the major target compart ments within the respiratory system, the tracheobronchial airway tree. Indi vidual airway segments respond uniquely to toxic stress and this response i nvolves not only the target cell population, e.g. epithelium, but also othe r components of the airway wall suggesting a trophic interaction within all components of the airway wall in maintaining steady state and responding t o injury. A number of biological factors modulate the nature of the respons e, including: (1) metabolic potential at specific sites for activation and detoxification; (2) the nature of the local inflammatory response; (3) age of the organism at the time of exposure; (4) gender of the exposed organism ; (5) history of previous exposure; and (6) species and strain of the organ ism exposed. (C) 2001 Published by Elsevier Science Ireland Ltd. All rights reserved.