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.

Acute moderate-intensity exercise in middle-aged men has neither an anti- nor proinflammatory effect

“…The overall impact of such changes could potentially affect proatherosclerotic aspects of cell function (adherence to stimulated endothelial cells and leukocyte cytokine secretion). For example, a single bout of exercise has been shown to reduce lymphocyte adhesion to cultured endothelial cells (17). However, in the present study, we did not observe changes in any of these measures (leukocyte cell count, CRP, IL-6, IL-10, lymphocyte HO-1, or lymphocyte adhesion) over a 7-day period in response to a single bout of moderate-intensity exercise.…”

“…to show the same response (17). The subjects in the present investigation were similar in characteristics to these unfit individuals, and it appears that an acute bout of moderateintensity exercise in middle-aged men has no effect on either the expression of a key anti-inflammatory gene in lymphocytes (HO-1) or lymphocyte-endothelial adhesion ex vivo.…”

High-Intensity Training Reduces CD8+ T-cell Redistribution in Response to Exercise

“…For example, physically fit individuals, who engage regularly in exercise training, exhibit a smaller exerciseinduced lymphocytosis compared with unfit individuals, which is independent of absolute exercise intensity (16,29). It has previously been reasoned that ß2-adrenergic receptors are desensitized owing to repeated exercise-induced adrenergic activity (16,29). Also consistent with our findings is the observation that relative to unfit individuals, physically fit individuals tended to show more modest epinephrine responses to stress and exercise tasks (16).…”

“…The observed blunting of epinephrine and CD8^TL responses to acute exercise after high-intensity training is consistent with previous reports. For example, physically fit individuals, who engage regularly in exercise training, exhibit a smaller exerciseinduced lymphocytosis compared with unfit individuals, which is independent of absolute exercise intensity (16,29). It has previously been reasoned that ß2-adrenergic receptors are desensitized owing to repeated exercise-induced adrenergic activity (16,29).…”

The potential anti-inflammatory benefits of improving physical fitness in hypertension

“…For example, the exercise-induced increase in cells expressing CD11a is greater in less fit, than it is in fit, individuals [81]. Similarly, the proportion of PBMC exhibiting endothelial adhesion post-exercise is attenuated by physical fitness [82]. These positive findings from cross-sectional studies augur well for the prospective investigations with exercise interventions (reviewed below), especially in inflammatory-related diseases.…”