title: Caffeine affects CD8+ lymphocyte apoptosis and migration differently in naïve and familiar individuals following moderate intensity exercise.
abstract: The purpose of this investigation was to determine the lymphocyte subset response to 30 min of moderate treadmill exercise during caffeine supplemented (6.0 mg.kg(-1)) and placebo conditions in caffeine-naïve and -familiar individuals. Seventeen individuals participated (caffeine-familiar = 8, caffeine-naïve = 9) completing two exercise bouts (caffeine supplemented and placebo control) 48 h apart in a counterbalanced and double-blinded fashion. Individuals were classified as follows: caffeine-naive <50 mg.d(-1) and caffeine-familiar >200 mg.d(-1) Whole blood samples were obtained at rest, 30 min after caffeine or placebo ingestion, immediately following exercise, and 1 h post exercise. Blood was used to analyze apoptosis (annexin V) and cellular migration (CX3CR1) responses in lymphocyte subsets (CD4+, CD8+, CD19+). Absolute changes from rest values were calculated and differences between conditions were determined through Chi-squared analysis with significance accepted at P <0.05. With regard to CD4+ and CD19+ lymphocytes, the interaction of caffeine and exercise did not affect naïve individuals to a greater extent immediately post exercise when compared to familiar, as similar apoptotic and migratory responses were observed (P >0.05). However, CD8+ lymphocyte cell death and migration responses were observed to be significantly greater at each sampling point in caffeine-familiar individuals (P <0.05). It is possible that chronic caffeine supplementation may prime CD8+ cell receptors for responsiveness to apoptosis and migration and the consequence of this form of immunosuppression in the post-exercise period should be determined.
authors.affiliation: Department of Kinesiology and Nutrition Sciences, University of Nevada, Las Vegas, Las Vegas, NV, USA james.navalta@unlv.edu.
authors.forename: James W
authors.initials: JW
authors.lastname: Navalta
authors.affiliation: Department of Kinesiology, Recreation, and Sport, Western Kentucky University, Bowling Green, KY, USA.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Fedor
authors.affiliation: Department of Kinesiology, Recreation, and Sport, Western Kentucky University, Bowling Green, KY, USA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Schafer
authors.affiliation: Department of Kinesiology, Recreation, and Sport, Western Kentucky University, Bowling Green, KY, USA.
authors.forename: T Scott
authors.initials: TS
authors.lastname: Lyons
authors.affiliation: Graduate Program on Physical Education, Catholic University of Brasilia, Brasilia, Brazil.
authors.forename: Ramires A
authors.initials: RA
authors.lastname: Tibana
authors.affiliation: Graduate Program on Physical Education, Catholic University of Brasilia, Brasilia, Brazil.
authors.forename: Guilherme B
authors.initials: GB
authors.lastname: Pereira
authors.affiliation: Graduate Program on Physical Education, Catholic University of Brasilia, Brasilia, Brazil.
authors.forename: Jonato
authors.initials: J
authors.lastname: Prestes
mesh_terms: D000328:Adult; D017209:Apoptosis / Q000187:drug effects*; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects*; D002110:Caffeine / Q000494:pharmacology*; D002465:Cell Movement / Q000187:drug effects*; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000379:methods; D005260:Female; D006801:Humans; D018655:Lymphocyte Count / Q000379:methods; D008297:Male; D055815:Young Adult
chemical_list: D002110:Caffeine
keywords: cytotoxic T cell; ergogenic supplement; exercise-induced lymphocytopenia; methylxanthine; programmed cell death