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

Acute psychological stress induces a prolonged suppression of the production of reactive oxygen species by phagocytes

Possible effects of psychological stress on the function of phagocytic cells have thus far hardly been investigated. In this study, we examined the phagocytic production of reactive oxygen species (ROS) in 10 healthy subjects undergoing a brief mental stressor. In a crossover design, the same subjects served as their own unstressed controls on a second experimental date. The acute laboratory stress resulted in a suppressed circadian rhythm of ROS production and in a decreased overall formation of ROS throughout the day. Especially under conditions of chronic stress, this finding may be of importance for the host's defense against infectious diseases.

Acute psychological stress simultaneously alters hormone levels, recruitment of lymphocyte subsets, and production of reactive oxygen species

Very little is known about the effects of acute psychological stress on the production of reactive oxygen species (ROS) by human phagocytic cells and the interplay between subjectively perceived stress, mediating hormones, variations in the number of peripheral leukocytes and ROS production. We measured psychological reactions, cardiovascular parameters, plasma catecholamines, plasma prolactin and cortisol as well as peripheral lymphocyte subsets in 13 experimental subjects undergoing a brief psychological stressor, and production of ROS, as indicated by chemiluminescence (CL), in stressed subjects and in healthy controls. The stressor elevated anger (p<0.01) and cardiovascular activation (p<0.01). There were significant changes in plasma levels of cortisol (p<0.01) and prolactin (p<0.001). During psychological stress natural killer (NK) cells (p<0.01) and CD8/CD38 cells (p<0.05) increased and returned to baseline only 25 minutes later. Significant changes in the number of naive CD4+/CD45RA+ (p<0.01) and antigen-experienced CD8+/CD45RO+ T cells (p<0.05) occurred. Subjects with stronger cardiovascular reaction showed higher stress-related plasma levels of norepinephrine (p<0.05) and were mainly responsible for the increase in NK cells. We observed a significantly reduced production of ROS following the stress test (p<0.05). Our results show that psychological stress is expressed simultaneously on psychological, hormonal and immunological levels of the organism. We show the existence of a circadian rhythm leading to a pronounced increase in CL during the morning hours. This first study taking this circadian rhythm in account revealed a significant suppressive effect of stress on ROS production.

Comparison of circulating phagocyte oxidative activity measured by chemiluminescence in whole blood and isolated polymorphonuclear leukocytes

The generation of reactive oxygen species (ROS) was measured by chemiluminescence (CL) in whole blood and isolated polymorphonuclear leukocytes (PMNLs) in 113 subjects. There were no differences in ROS production in males and females, smokers and non-smokers and no age dependency. A significant correlation was found between whole blood CL parameters and between parameters derived from isolated cells, but there was no correlation when these parameters were compared using isolated PMNLs and whole blood. Variations in serum lipid levels did not account for the variability of CL parameters in blood or PMNLs. Both methodologies had the same validity in demonstrating priming of phagocytes. Zymosan-induced CL was more sensitive in detecting distinct functional states of phagocytes than FMLP-induced CL.