Protein Z Plasma Levels in Different Phases of Activity of Coronary Atherosclerosis

Abstract number: P1254

Fedi S, Sofi F, Cesari F, Vigiani S, Fatini C, Marcucci R, Giglioli C, Margheri M, Abbate R, Gensini GF

Protein Z (PZ) is a vitamin-K-dependent glycoprotein which shows structural homologies with many coagulation factors. Data from literature suggest that PZ plays an important role in inhibiting coagulation as it serves as cofactor for the inactivation of factor Xa by forming a complex with the plasma protein Z-dependent protease inhibitor. We previously reported that low PZ plasma levels are associated with acute coronary syndromes (ACS). Aim of the present study was to evaluate PZ plasma levels in different phases of activity of coronary atherosclerosis. Therefore, we measured PZ plasma levels in 3 different groups of subjects: 166 (131 M; 35 F) patients with a clinical history of ACS who have been event-free for the last year before the investigation (group A); 166 (131 M; 35 F) patients admitted with a diagnosis of ACS to the Coronary Unit of University of Florence (group B), and 332 (262 M; 70 F) controls (group C) comparable for age and gender with the other two groups. None had liver or renal dysfunction nor showed a positivity for antiphospholipid antibodies or for factor V Leiden mutation. Moreover, none was under warfarin therapy. Mean PZ plasma levels were found to be significantly (P < 0.0001) lower in group A (1327.6 ± 690.7 ng/mL) as compared to group B (1475 ± 684.1 ng/mL) and group C (1650.1 ± 634.5 ng/mL). Moreover, PZ levels below the 5^th percentile (609.3 ng/mL) of normal values distribution in control subjects were found in 24.7% of patients in group A, in 19.3% of patients in group B and in 4.8% of subjects in group C (P < 0.0001). In conclusion, these results confirm our previous data on low PZ plasma levels in ACS and indicate that low PZ plasma levels are present even in a chronic phase of activity of atherosclerotic disease.