Alterations of regular and mature monocytes are distinct, and dependent of intensity and duration of exercise

Circulating monocytes comprise functionally distinct regular (CD14^bright+) and mature (CD141^low+) cells. Cell surface receptors were determined by three colour flow cytometry in 8 healthy control subjects. Compared to regular monocytes, mature monocytes had lower levels of the high affinity Fcy receptor 1 (CD64), complement receptor 3 (CDllb), CD45RO and higher levels for HLA-DR, LFA-1 (CD11a/CD18), interleukin-2 receptor (CD25), CD45RA and the Fcγ receptor 3 (CD16). Both regular and mature monocytes were measured before and up to three hours after four different types of exercise (Ex) in endurance trained athletes (n=9-16). Immediately after anaerobic exercise of I min with a maximal lactate concentration (la_max) of I2.3 (SD I.4) mmol · l^-1 and exhaustive exercise of 24 (SD 8) min with a maximal lactate concentration (la_max) of 7.4 (SD 2.6) mmol· l^-1 mature monocytes increased more than regular monocytes. Exhaustive endurance exercise of 87 (SD 21) min [la_max 3.7 (SD I.0)] led to a similar increase of regular and mature monocytes. 15-33 min after a 100km run regular monocytes increased significantly, whereas mature monocytes decreased. Up to three hours after the end of all exercises mature monocytes fell below pre-exercise values. In conclusion, duration and intensity of exercise alter distinct maturation stages of monocytes differently. It is probable that the avidity of adhesion molecules like LFA-1 to their endothelial ligands is increased to enable the firm attachment to the endothelium.