Effects of an exercise challenge on mobilization and surface marker expression of monocyte subsets in individuals with normal vs. elevated blood pressure.

High blood pressure (BP) and monocyte activation are associated with atherogenic processes. Especially, CD16 expressing monocytes are shown to be activated in many inflammatory conditions but their characteristics in hypertension is unknown. We compared CD16(++), CD16(+) and CD16(-) monocyte populations and their cellular adhesion molecule (CAM), chemokine receptor, and activation marker expression in response to a moderate 20-min treadmill exercise bout at 65-70% V O(2peak) in 44 participants with elevated (EBP) or normal BP (NBP). Blood was drawn before, immediately after, and 10min after exercise. Phenotyping of monocytes and detection of surface markers were done by flow cytometry. Monocyte subset by exercise [pre, post, 10-min post] repeated measures ANOVA and group [EBP vs. NBP] by exercise repeated measures of ANCOVA with age, BMI, and fitness as covariates were employed. Circulating numbers of all the three monocyte subsets increased after exercise (p<0.001), with the largest % increase for CD16(+)CD14(++). Percents of CD16(++)CD14(+) and CD16(+)CD14(++) increased, whereas % CD16(-)CD14(++) decreased (p<0.001). Also, pre to post exercise changes in CD62L, CD11b, CXCR2, and HLA-DR expression were different among the monocyte subsets (p's<0.001). BP status did not significantly affect monocyte subset trafficking, although post-exercise changes in CD62L and CXCR2 levels were greater in EBP individuals (p<0.05). We conclude that exercise leads to a different mobilization among monocyte subsets based on CD16 expression. Individuals with high BP showed greater responses to a physical challenge in some monocyte chemokine receptors and selectins, but its clinical implications need further examination.