title: Influence of age on the release of reactive oxygen species by phagocytes as measured by a whole blood chemiluminescence assay.
abstract: Polymorphonuclear and mononuclear phagocytes play an important role in host defense, but may also cause tissue injury through excessive inflammation. Reactive oxygen species (ROS) are not only directly ore indirectly involved in a wide variety of clinical disorders, such as atherosclerosis, reperfusion injury, pulmonary toxicity and cancer, but they are also important in the aging process. This process is associated with increasing susceptibility to infection. In this study we investigated the influence of age and sex on phagocyte activation by means of a whole blood chemiluminescence (CL) assay. Circulating phagocyte activity was measured in 55 healthy volunteers (24 females, 31 males) aged from 6 to 92 years. Using an automated luminescence system, phagocytes were stimulated by polystyrene beads and Luminol-enhanced CL was determined in terms of peak height and peak time in freshly withdrawn, peripheral venous whole blood. An extremely significant positive correlation (p < 0.0001) between the maximum of light emission after stimulation and increasing age was found. This finding is true for the total population of blood phagocytes as well as for a single cell. In contrast the time of the appearance of the maximum of light emission showed an extremely significant inverse correlation (p < 0.0003) with increasing age. The influence of sex on the CL-parameters showed no significant difference between women and men. It is concluded that the increased susceptibility of circulating phagocytes to oxidative burst in elderly subjects may be the consequence of several biological events. Senescent cells express more and also have new antigens on their surfaces that trigger an autoimmune response. Cellular senescence appears earlier in old organisms. Therefore phagocytes in aging individuals may be increasingly involved in their scavenger tasks that grow with the catabolic bias in cell turnover. Moreover, atherosclerotic alterations in the intima and endothelial lesions are physiologic concomitants of age and may lead to a stimulation of circulating phagocytes.
authors.affiliation: Institute of Biochemistry, Karl Franzens University of Graz, Austria.
authors.forename: E M
authors.initials: EM
authors.lastname: Kukovetz
authors.forename: G
authors.initials: G
authors.lastname: Bratschitsch
authors.forename: H P
authors.initials: HP
authors.lastname: Hofer
authors.forename: G
authors.initials: G
authors.lastname: Egger
authors.forename: R J
authors.initials: RJ
authors.lastname: Schaur
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D002648:Child; D005260:Female; D006801:Humans; D008163:Luminescent Measurements; D008297:Male; D008875:Middle Aged; D010586:Phagocytes / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*
chemical_list: D017382:Reactive Oxygen Species