EXPRESSION OF INDUCIBLE NITRIC-OXIDE SYNTHASE IN HUMAN LUNGS

The aim of this study was to investigate the expression of inducible n itric oxide synthase (iNOS) in lungs of patients with or without adult respiratory distress syndrome (ARDS). We compared the expression of i NOS by immunohistochemical analysis and polymerase chain reaction in t he human lungs collected during open-lung biopsy or at autopsy. The ex pression of iNOS mRNA was present in all lung samples; however, only 3 out of 11 lung samples showed weak staining for iNOS. Although the in volvement of nitric oxide in animal models of ARDS is reported, produc tion of nitric oxide in human lungs is still controversial. The data p resented here suggest that human lungs express iNOS mRNA but that the production of iNOS protein may be tightly regulated and is expressed i n pulmonary inflammation.