title: Constitutive pro- and anti-inflammatory cytokine and growth factor response to exercise in leukocytes.
abstract: Leukocytosis following exercise is a well-described phenomenon of stress/inflammatory activation in healthy humans. We hypothesized that, despite this increase in circulating inflammatory cells, exercise would paradoxically induce expression of both pro- and anti-inflammatory cytokines and growth factors within these cells. To test this hypothesis, 11 healthy adult men, 18-30 yr old, performed a 30-min bout of heavy cycling exercise; blood sampling was at baseline, end-exercise, and 60 min into recovery. The percentage of leukocytes positive for intracellular cytokines and growth factors and mean fluorescence intensity was obtained by flow cytometry. Proinflammatory cytokines (IL-1alpha, IL-2, IFN-gamma, and TNF-alpha), a pleiotropic cytokine (IL-6), and anti-inflammatory cytokines and growth factors [IL-4, IL-10, growth hormone (GH), and IGF-I] were examined. Median fluorescence intensity was not affected by exercise; however, we found a number of significant changes (P < 0.05 by mixed linear model and modified t-test) in the numbers of circulating cells positive for particular mediators. The pattern of expression reflected both pro- and anti-inflammatory functions. In T-helper lymphocytes, TNF-alpha, but also IL-6, and IL-4 were significantly increased. In monocytes, both IFN-gamma and IL-4 increased. B-lymphocytes positive for GH and IGF-I increased significantly. GH-positive granulocytes also significantly increased. Collectively, these observations indicate that exercise primes an array of pro- and anti-inflammatory and growth factor expression within circulating leukocytes, perhaps preparing the organism to effectively respond to a variety of stressors imposed by exercise.
authors.affiliation: Department of Pediatrics, Pediatric Exercise Research Center, University Children's Hospital, University of California, Irvine, USA.
authors.forename: Frank
authors.initials: F
authors.lastname: Zaldivar
authors.forename: Jessica
authors.initials: J
authors.lastname: Wang-Rodriguez
authors.forename: Dan
authors.initials: D
authors.lastname: Nemet
authors.forename: Christina
authors.initials: C
authors.lastname: Schwindt
authors.forename: Pietro
authors.initials: P
authors.lastname: Galassetti
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Mills
authors.forename: Lori D
authors.initials: LD
authors.lastname: Wilson
authors.forename: Dan M
authors.initials: DM
authors.lastname: Cooper
mesh_terms: D000293:Adolescent; D000328:Adult; D000893:Anti-Inflammatory Agents / Q000378:metabolism*; D016207:Cytokines / Q000378:metabolism*; D015444:Exercise / Q000502:physiology*; D006098:Granulocytes / Q000378:metabolism; D019382:Human Growth Hormone / Q000378:metabolism; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D007378:Interleukins / Q000378:metabolism; D007962:Leukocytes / Q000378:metabolism*; D018655:Lymphocyte Count; D008214:Lymphocytes / Q000378:metabolism; D008297:Male; D009000:Monocytes / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D000893:Anti-Inflammatory Agents; D016207:Cytokines; D018836:Inflammation Mediators; D036341:Intercellular Signaling Peptides and Proteins; D007378:Interleukins; D014409:Tumor Necrosis Factor-alpha; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I