Expression of anaphylatoxin receptors on platelets in patients with coronary heart disease

Abstract Objective : Inhibition of components of the complement system or of its receptors has been postulated as a concept for primary and secondary prevention in atherosclerosis and was applied in clinical trials. Although the anaphylatoxin-receptors C3aR and C5aR are commonly associated with inflammatory cells, in vitro studies suggested their expression also on platelets. Methods and Results : Expression levels of C3aR and C5aR were measured by flow cytometry in a collective of 302 patients with documented coronary artery disease (CAD) including patients with stable CAD (n = 152), unstable angina (n = 54), acute myocardial infarction (AMI; Non-ST elevation myocardial infarction, n = 70, ST elevation MI, n = 26) or healthy controls (n = 21). Patients with stable CAD, unstable angina or AMI had significantly higher expression of C5aR on platelets in comparison to healthy controls (MFI 14.68 (5.2), 14.56 (5.18) and 13.34 (4.52) versus 10.68 (3.1)); p   0.001 for C3aR, r = 0.76 for C5aR, p  Conclusion : In summary, we observed a positive correlation between the expression of anaphylatoxin-receptors C3aR and C5aR with platelet activation in patients with CAD. Further investigations are needed to study the clinical and mechanistic relevance of these findings.