What happens with ageing: decline or remodeling of opsonin-independent phagocyte oxidative activity?

Changes that occur with age in the opsonin-independent oxidative activity of peripheral phagocytes in whole blood were examined by means of luminol chemiluminescence (LCL). The chemiluminescence was registered simultaneously by non-stimulated and stimulated cells and the age-related alterations of total and extracellular generation of reactive oxygen species (ROS) were studied using model systems. It was found that the rate of phagocyte activation by the glass surface of the measuring chambers, assessed by the time of the peak appearance after the start of LCL response, increased. However, the maximum oxidative activity and the integral oxidative capacity of the cells during adhesion, evaluated by the maximum LCL intensity and the area under the LCL curve, respectively, declined. No age-dependence of formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated oxidative cellular activity for total ROS generation was detected. The maximum oxidative activity and the integral oxidative capacity of peripheral phagocytes to generate extracellular superoxide in response to fMLP was decreased. The likely causes for the observed alterations in phagocyte function are discussed and an analysis of the obtained results is given on the background of the contradictory data published on phagocyte oxidative activity age-related changes.