Cell Adhesion Molecules in Response to Physical and Mental Stress

Abstract

INTRODUCTION: Soluble cell adhesion molecules (sCAM) are increased following maximal aerobic exercise, likely in response to elevated HR and increased shear stress in the vasculature. Shedding of adhesion molecules from the endothelium, an anti-atherogenic process, may be facilitated during physical activity. Mental stress elicits increased cardiovascular shear stress, however it is unclear how mental stress affects levels of circulating sCAM. PURPOSE: To examine concentrations of vascular cell adhesion molecule-1 (VCAM-1) and CX3CL1 (fractalkine) following physical and mental stress in adult males. METHODS: Twenty males were recruited and completed a maximal aerobic treadmill test and a 20-minute mental stress task (Stroop Color-Word and Mental Arithmetic) on separate, non-consecutive days. HR was measured at baseline and during exercise and mental stress. Blood was collected at baseline, immediately after (POST) and 30 minutes following (POST30) exercise and mental stress. Soluble VCAM-1 and fractalkine were quantified in participant sera via standard ELISA. RESULTS: The HR response to exercise was significantly greater than that elicited by mental stress (178.03±77.59 % vs. 39.08±14.50 % [p<0.001]). VCAM-1 and fractalkine were significantly increased POST exercise (VCAM-1: 815.74±139.55 ng/mL vs. 738.67± 131.59 ng/mL (p=0.002); fractalkine: 1032.37±334.94 pg/mL vs. 596.47±201.88 pg/mL (p=0.000) before returning to concentrations similar to baseline at POST30. There were no changes in either VCAM-1 (p=0.131) or fractalkine (p=0.146) following acute mental stress. CONCLUSIONS: Exercise produced the largest increase in HR. Interestingly, only exercise increased VCAM-1 and fractalkine concentrations in the serum of young males. Mental stress did not significantly alter VCAM-1 or fractalkine concentrations. These data suggest that the anti-atherogenic endothelial shedding of CAM may not take place during the acute mental stress response.