Heme oxygenase-1 expression is down-regulated by angiotensin II and under hypertension in human neutrophils.
BACKGROUND We recently demonstrated that arachidonic:linoleic acid ratio of erythrocytes of essential hypertension patients is greater than normal. OBJECTIVE To investigate fatty acid composition, capability for adhesion to biological substrate and expression of beta2 integrins of leucocytes obtained from peripheral blood and skin window exudate of essential hypertension patients. DESIGN Neutrophil activation state was evaluated by reproducing the various conditions occurring in vivo during the life of the cell (i.e. under the 'resting' condition, such as in peripheral blood, and 'primed' condition, such as after transmigration through the endothelium and after administration of specific chemo-attractants). Because both peripheral blood and skin window leucocytes of the subjects were obtained on the same day, we could be sure that there had been no dietary influences on changes in levels of fatty acid. Thus, the observed changes should reliably reflect the metabolic rate of utilization of fatty acids coupled to the activation and migration of cells. RESULTS Leucocytes from essential hypertension patients were richer in arachidonic acid than were the corresponding cells from normotensive subjects; this difference was also evident for functionally activated skin window leucocytes, in spite of there having been a greater loss of poly-unsaturated fatty acids and arachidonic acid after migration. Moreover, a greater than normal arachidonic acid:linoleic acid ratio was shown for the first time to apply for leucocytes of essential hypertension patients, so extending our previous findings on the erythrocytes. Leucocytes from essential hypertension patients, collected both from peripheral blood and from skin window exudate, proved far more adhesive than the corresponding cells from age-matched and sex-matched controls, but this was not associated with a quantitative hyperexpression of beta2 integrins. CONCLUSIONS The results suggest that an increase in availability of arachidonic acid in leucocytes could be a further expression of the generalized disturbance of fatty acid levels associated with essential hypertension and that a condition of hyperadhesion of neutrophils could occur spontaneously in vivo during the course of hypertension.