Effects of paraoxonase activity and gene polymorphismon coronary vasomotion
Paraoxonase 1 (PON1) is recognized as a protective enzyme against LDL oxidation and PON1 polymorphism has been described as a factor influencing coronary heart disease (CHD) free survival. As coronary vasoreactivity is a surrogate of future cardiovascular event, we aimed at assessing the respective effect of PON1 genotype and phenotype on coronary vasoreactivity in a population of type 2 diabetic patients.
Methods:
Nineteen patients with type 2 diabetes mellitus underwent a Rb-82 cardiac PET/CT to quantify myocardial blood flow (MBF) at rest, during cold pressor testing (CPT) and adenosine-induced hyperaemia to compute myocardial flow reserve (MFR).
They were allocated according to Q192R and L55M polymorphisms into 3 groups (wild-type and LM/QR heterozygotes; MM homozygotes; and RR homozygotes) and underwent a measurement of plasmatic PON1 activity. Relations between rest-MBF, stress-MBF, MFR, MBF response to CPT and PON1 genotypes and PON1 activity were assessed using Spearman correlation and multivariate linear regression analysis.
Results:
Although PON1 activity was significantly associated with PON1 polymorphism (p<0.0001), there was no significant relation between PON1 genotypes and rest-MBF, stress-MBF or MBF response to CPT (p[greater than or equal to]0.33).
PON1 activity significantly correlated with HDL plasma level (rho=0.63, p=0.005), age (rho=-0.52, p= 0.027) and MFR (rho=0.48, p=0.044). Moreover, on multivariate analysis PON1 activity was independently associated with MFR (p=0.037).
Conclusion:
Our study supports an independent association between PON1 activity and MFR.
Whether PON1 contributes to promote coronary vasoreactivity through its antioxidant activity remains to be elucidated. This putative mechanism could underlie the increased risk of CHD in patients with low PON1 activity.
Author: Vincent DunetJuan RuizGilles AllenbachPaola IzzoRichard JamesJohn Prior
Credits/Source: EJNMMI Research 2011, 1:27
Published on: 2011-11-18
Copyright by the authors listed above - made available via BioMedCentral (Open Access). Please
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