58 CHANGES IN HUMAN LIPOPROTEIN COMPOSITION IN PATIENTS WITH ACUTE CORONARY SYNDROME

The protein composition of lipoproteins may serve as biomarkers or reveal underlying mechanisms during different states of disease. Here we have analysed the protein composition of LDL and HDL from patients with acute coronary syndrome (ACS) and patients receiving statins after previous ACS. Plasma samples were obtained from males, namely 12 healthy donors, 9 patients with ACS and 7 stable patients receiving statin treatment after previous ACS. LDL and HDL were isolated by two-step density ultracentrifugation. LDL proteins were analysed with two-dimensional gel electrophoresis and mass spectrometry. Paraoxonase 1 (PON-1) in HDL was analyzed with SDSPAGE/Western Blot.Concentrations of apo A-IV, a1-antitrypsin and transthyretin were significantly increased (P < 0.05) in LDL from patients with ACS compared to healthy controls. In patients receiving statins, a1-antitrypsin remained increased while serum amyloid A4 was decreased. By western blot analysis, a non-significant increase in PON-1 was found in HDL from patients with ACS. Interestingly, a truncated form of PON-1 was detected in all patients with ACS but not in any of the controls.In conclusion, we confirm previous findings that LDL-associated transthyretin is a possible biomarker of myocardial infarction. Moreover, the increased concentration of the inflammatory marker a1-antitrypsin in LDL from both ACS patients and stable patients after ACS indicate that the enrichment does not only reflect an acute phase response. The presence of a truncated form of the antioxidant protein PON-1 in HDL may explain previous findings showing increased amounts but lower activity of PON-1 in patients with ACS.