Laboratory stress in normotensives, borderline hypertensives and essential hypertensives is associated with priming of phagocytic cells

Abstract

The present study was designed to investigate the effect of standardized laboratory physical and mental stress on phagocytic generation of reactive oxygen species (ROS) and hormonal responses in normotensives (NT), borderline hypertensives (BH) and essential hypertensives (EH). BH were characterized by increased neurohormonal activation in the prestress situation as indicated by significant higher noradrenaline and ACTH values. Although physical stress resulted in a marked activation of the sympatho-adrenal system in all groups, the BH group revealed a strong tendency of more pronounced sympatho-adrenal response. The intracellular and extracellular production of ROS was quantified using chemiluminescence (CL) assays. Phagocytic cells of NT, BH and EH responded to stress with a significantly enhanced zymosan-stimulated luminol- and lucigenin-amplified CL, predominantly localized intracellularly. In the BH group, but not in NT and EH, significant stress-related increases of extracellularly and intracellularly generated oxidative metabolites of isolated granulocytes after stimulation with the chemotactic peptide FMLP were found. Baseline values of all measured CL parameters did not differ between NT, BH and EH. The results show that stress is followed by priming of phagocytes for enhanced oxygen radical generation. In addition to stress-related activation of intracellular ROS production granulocytes of BH showed enhanced release of oxygen metabolites into the extracellular space.