Effects of short-term nitrogen monoxide inhalation on leukocyte adhesion molecules, generation of reactive oxygen species, and cytokine release in human blood

Increased nitrogen monoxide (NO) concentrations change leukocyte function u nder a multitude of experimental conditions, NO inhalation is an experiment al treatment for lung failure and exposes leukocytes to increased NO concen trations during passage through the lungs, To investigate whether short-ter m NO inhalation induces lasting changes in the function of circulating huma n leukocytes, venous blood samples were drawn from eight healthy male volun teers before and at the end of a 35-min period of breathing 40 ppm NO in 30 % O-2. The leukocytes in the samples were subsequently analyzed for NO-indu ced changes in expression of cell surface molecules, generation of reactive oxygen species (ROS), and cytokine production by flow cytometry and ELISA techniques. The results were (1) NO inhalation changed neither the baseline nor the Escherichia coli lipopolysaccharide (LPS)induced expression of the cell adhesion molecules CD11a, CD11b, CD11c, and CD62L (L-selectin) on neu trophilic granulocytes (PMN) or monocytes (Mo), The expression of CD14 and HLA-DR was also unchanged. (2) The generation of ROS in response to activat ion with phorbol myristate acetate increased in PMN after NO inhalation; an increase in Mo did not reach significance, (3) Baseline and LPS-stimulated production of IL-1 beta decreased after NO inhalation, while the LPS-stimu lated production of TNF-alpha increased. No changes in IL-6 production were detected. (C) 2000 Academic Press.