title: Physical fitness attenuates leukocyte-endothelial adhesion in response to acute exercise.
abstract: Studies suggest that physical fitness promotes cardiovascular health, including improved endothelial function and possibly reduced inflammatory responses to stressors. This study examined the effects of fitness on leukocyte-endothelial adhesion in response to an acute exercise challenge. Peripheral blood mononuclear cell (PBMC) adhesion to human umbilical venous endothelial cells (HUVEC) was examined in 18 more-fit and 19 less-fit individuals [mean age 39 yr (SD 11)] before and after a 20-min treadmill exercise at 65-70% peak oxygen consumption. PBMC were isolated from whole blood (Ficoll-Paque) at rest and immediately after exercise. HUVEC were incubated for 4 h in the presence of cytokines IL-1 and IL-8 to activate endothelial adhesion molecule expression. Fit subjects showed a significant reduction in PBMC-HUVEC adhesion after exercise (P < 0.01) compared with less-fit subjects, who showed no significant change. Regardless of fitness levels, both at rest and in response to exercise, soluble ICAM-1 in the incubation media attenuated PBMC-HUVEC adhesion by approximately 81% (P < 0.001). The findings indicate that immune cells that demarginate in response to exercise have reduced ability to adhere in individuals who are physically fit, an effect apparently independent of ICAM-1 binding. The findings provide evidence of how physical fitness might protect individuals from inflammatory responses to exercise.
authors.affiliation: Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA. pmills@ucsd.edu
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Mills
authors.forename: Suzi
authors.initials: S
authors.lastname: Hong
authors.forename: Laura
authors.initials: L
authors.lastname: Redwine
authors.forename: Steven M
authors.initials: SM
authors.lastname: Carter
authors.forename: Albert
authors.initials: A
authors.lastname: Chiu
authors.forename: Michael G
authors.initials: MG
authors.lastname: Ziegler
authors.forename: Joel E
authors.initials: JE
authors.lastname: Dimsdale
authors.forename: Alan S
authors.initials: AS
authors.lastname: Maisel
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D000328:Adult; D002448:Cell Adhesion / Q000502:physiology*; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006801:Humans; D007962:Leukocytes / Q000166:cytology / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D005082:Physical Exertion / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology*