Selected Abstracts Presented at the Annual Conference of the Canadian Society of Clinical Chemists (CSCC), Saint John, NB, 2-5 June 2019

Abstract

Low serum PON1 activities (paraoxon, phenyl-acetate or lactone substrates) are associated with coronary heart disease (CHD). We investigated the rate of diazoxon hydrolysis by PON1 in a population with CHD.Case- control study of 410 subjects with CHD and 274 controls. PON1 activity towards paraoxon and diazoxon, PON1 serum concentration and the PON1–55 and 192 polymorphisms were determined.There were no differences in the distribution of the PON1–55 or PON1–192 genotypes between the CHD and controls, however, PON1 activity towards diazoxon (DIAZ) was significantly (+160%) higher in CHD. In the control population, DIAZ was significantly different between the PON1–192 genotypes in the order QQ > QR > RR (P < .001). However, in CHD the order was QQ > QR = RR. In CHD DIAZ was significantly higher in all the PON1–192 and 55 genotypes compared to controls. In both populations DIAZ was significantly different between the PON1–55 genotypes in the order LL > LM > MM (P < .001).If this result can be replicated in other studies and/or with other PON1 substrates, there may be major diagnostic and mechanistic implications for the relationship of PON1 and CHD.