Combined antiplatelet therapy reduces the pro-inflammatory properties of activated platelets

The cause of atherothrombosis is rupture or erosion of atherosclerotic lesions, leading to an increased risk on myocardial infarction or stroke. Here, platelet activation plays a major role, leading to the release of bioactive molecules, e.g. chemokines and coagulation factors, and to platelet clot formation. Several antiplatelet therapies have been developed for secondary prevention of cardiovascular events, in which anticoagulant drugs are often combined. Besides playing a role in haemostasis, platelets are also involved in inflammation. However, it is unclear whether current antiplatelet therapies also affect platelet immune functions. In this study, the possible anti-inflammatory effects of antiplatelet medications on chemokine release were investigated using ELISA and on the chemotaxis of THP-1 cells towards platelet releasates. The cause of atherothrombosis is rupture or erosion of atherosclerotic lesions, leading to an increased risk on myocardial infarction or stroke. Here, platelet activation plays a major role, leading to the release of bioactive molecules, e.g. chemokines and coagulation factors, and to platelet clot formation. Several antiplatelet therapies have been developed for secondary prevention of cardiovascular events, in which anticoagulant drugs are often combined. Besides playing a role in haemostasis, platelets are also involved in inflammation. However, it is unclear whether current antiplatelet therapies also affect platelet immune functions. In this study, the possible anti-inflammatory effects of antiplatelet medications on chemokine release were investigated using ELISA and on the chemotaxis of THP-1 cells towards platelet releasates. We found that antiplatelet medication acetylsalicylic acid (ASA) led to reduced chemokine (C-C motif) ligand 5 (CCL5) and chemokine (C-X-C motif) ligand 4 (CXCL4) release from platelets, while leukocyte chemotaxis was not affected. Depending on the agonist, αIIbβ3- and P2Y12-inhibitors also affected CCL5 or CXCL4 release. The combination of ASA with a P2Y12 inhibitor or a phosphodiesterase inhibitor did not lead to an additive reduction on CCL5 or CXCL4 release. Interestingly, these combinations did reduce leukocyte chemotaxis. This study provides evidence that combined therapy of ASA and a P2Y12 or PDE3 inhibitor can decrease the inflammatory leukocyte recruiting potential of the releasate of activated platelets.