Expression of xenobiotic-metabolizing enzymes in human pulmonary tissue: possible role in susceptibility for ILD.

The lung is a major target for all inhaled toxicants. Many inhaled chemicals are not hazardous as such, but are biotransformed to reactive intermediates. Therefore, the pathogenesis of interstitial and other lung diseases is intimately linked to exposure to environmental and other chemicals, which may be causative or modifying factors in the cellular pathways and mechanisms mediating oxidative stress and cell protection in the pulmonary tissue. Several different xenobiotic-metabolizing cytochrome P450 (CYP) and phase II enzymes (i.e. conjugation enzymes including several transferases) are present in the human lung and lung-derived cell lines, possibly contributing to in situ activation and inactivation of chemical toxicants. This paper describes the expression and localization of individual CYP-forms in the lung. Interindividual differences in the expression of these enzymes may contribute to the risk of developing interstitial and other lung diseases initiated by agents that require metabolic activation.