PROPROTEIN CONVERTASE SUBTILISIN/KEXIN TYPE 9 (PCSK9) CONCENTRATION IN BLOOD OF MEN OF DIFFERENT POPULATION SUBGROUPS AND ITS ASSOCIATION WITH UNFAVORABLE LONG-TERM PROGNOSIS

The aim of the study was to investigate proprotein convertase subtilisin/kexin type 9 (PCSK9) concentration in men of different population subgroups, its associations with cardiovascular risk factors and with unfavorable 7(years long-term prognosis. The study took three subgroups of men from a population sample of residents of Novosibirsk, at the age of 44– 73 years, not using lipid-lowering drugs (including statins): the population subgroup (183 men), the subgroup with a hypercholesterolemia (46 men), and a subgroup with hypocholesterolemia (18 men). PCSK9 blood levels were determined by ELISA using the test-systems “Human Proprotein Convertase 9/PCSK9 Immunoassay” (R&D Systems). Long-term prognosis (myocardial infarction, cardiovascular death) were studied 7 years after the examination of population subgroups of men using data of the Register of Cardiovascular Mortality and Register of Myocardial Infarction. The outcome showed a normal PCSK9 distribution in population subgroups of men with hyper- and hypocholesterolemia and the abnormal distribution shifted to the left in the population group of men. Concentration of PCSK9 protein in the subgroup of men with hypercholesterolemia was by 1.2 times higher than in the population group of men. Statistically significant correlations of PCSK9 protein level with total cholesterol, LDL cholesterol, and glucose were found. PCSK9 variability was due to the influence of other factors only by 15% (R Square=0.155, p<0.001). Significant influences of HDL-cholesterol levels (Beta=0.238, p=0.023), TG (Beta=0.253, p=0.049) and LDL cholesterol (Beta=0.751, p=0.009) to protein PCSK9 blood level were revealed. Multivariate regression analysis showed a significant independent association of PCSK9 protein levels with the fact of cardiovascular death in a 7-year long-term period (p=0.048, OR=1.01). The results indicated that, in men with increasing blood levels of PCSK9 protein (by 1 ng/mL), the relative risk for cardiovascular death increased by 1% within 7 years after the examination independently of other parameters.

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