Background: Many pathogenic processes and diseases are the result of an erroneous activation of the complement cascade and a number of inhibitors of complement have thus been examined for anti-inflammatory actions. It was recently demonstrated that supraphysiological concentrations of the endogenous complement inhibitor MAp44 (also denoted MAP1) protect against myocardial reperfusion injury. In the present study, we examined the association between outcome after acute myocardial infarction (MI) and the plasma levels of MAp44 and its related proteins MASP-1 and MASP-3 in patients with first-time MI. In addition, we compared plasma levels of MAp44, MASP-1, and MASP-3 in MI patients to levels in a healthy control group.
Methods: A total of 192 MI patients and 140 control persons were included. Plasma samples were obtained and analysed with time-resolved immunofluorometric assays determining the plasma levels of MAp44, MASP-1, and MASP-3. The myocardial outcomes (salvage index and final infarct size) were measured by gated single-photon emission CT.
Results: MI patients had 18 % higher plasma levels of MAp44 (IQR 11-25%) as compared to the healthy control group (p<0.001. However, neither salvage index (Spearman rho -0.1, p=0.28) nor final infarct size (Spearman rho 0.02, p=0.83) correlated with plasma levels of MAp44. Likewise, MASP-1 and MASP-3 were elevated in MI patients (p=0.002 and p<0.001), but the levels were not correlated to outcome.
Conclusions: Plasma levels of MAp44, MASP-1, and MASP-3 are significantly higher in patients with MI compared to healthy control persons, but are not associated with short-term outcome measured as salvage index and final infarct.
Keywords: Complement system; immunology; myocardial infarction; reperfusion.