Differentiation of platelet–leukocyte conjugate formation by short term exercise

Abstract

Platelet–leukocyte conjugates are increased in cardiovascular disease, but exercise is also able to trigger platelet–leukocyte formation in healthy subjects. The aim was to investigate the heterogeneity of platelet–leukocyte conjugate formations triggered by short term exercise. 18 healthy non‐smokers underwent a 90 second maximal test on a SRM™ cycle ergometry system and a control experiment. Blood samples were taken after 30 min rest, immediately before and after, 15 min and 1 h after exercise. The different platelet–leukocyte conjugates were detected by flow cytometry via CD45, CD14, CD16, CD41, together with CD62P antibodies for the investigation of platelet activation in the conjugates. In addition, a stimulation of conjugate formation in vitro with 8 μM TRAP‐6 was initiated. Immediately after exercise platelet–granulocyte (+24%), and –lymphocyte (+17%) conjugates were increased (p<0.01), while the platelet–monocyte conjugates (+40%) were enhanced (p<0.05) 15 min after exercise. The differentiation after stimulation showed that the regular (CD14⁺16⁻; +32%) and mature (CD14⁺16⁺; +35%) monocytes were both increased after exercise (p<0.01) but the regular monocytes were preferred (p<0.001) in platelet–monocyte conjugate formation. In addition, these conjugates revealed the highest CD62P expression.

Maximal short term exercise is useful for the investigation of platelet–leukocyte formation; e.g., it could be shown, that regular monocytes may be preferred in conjugate formation and that these conjugates revealed the highest CD62P expression.