Addressing the link between paraoxonase-1 gene variants and the incidence of early onset myocardial infarction

Introduction

The enzyme paraoxonase-1 (PON1) represents an endogenous defense mechanism against vascular oxidative stress, thereby contributing to the prevention of atherosclerosis. Several polymorphisms have been reported in the PON1 gene, including Q192R. PON1 phenotype is commonly expressed as the paraoxonase/arylesterase ratio (PON/ARE). The major aim of this study was to investigate the association between PON1 Q192R polymorphism, PON1 phenotypes and the incidence of early-onset acute myocardial infarction (AMI) in Egyptians.

Material and methods

The study subjects consisted of 102 AMI patients and 72 age-matched healthy controls. Genotyping and enzyme activities were determined using PCR-RFLP and kinetic spectrophotometric assays, respectively.

Results

The genotype distribution for the PON1 gene was significantly different between AMI patients (QQ = 38.24%, QR = 49.02%, RR = 12.75%) and controls (QQ = 66.67%, QR = 25%, RR = 8.33%). Allele frequencies were also significantly different between patients (Q = 62.75%, R = 37.25%) and controls (Q = 79.17%, R = 20.83%). The genotypes QR and RR showed higher risk for AMI compared to the homozygous QQ (odds ratio (OR) = 3.231, p < 0.001). The average PON/ARE ratio in MI patients (1.187 ±0.1) did not differ significantly from controls (1.118 ±0.26). However, it showed a significant difference among different genotypes in both AMI patients (QQ = 0.91 ±0.11, QR = 1.09 ±0.11 and RR = 2.65 ±0.4) (p = 0.0002) and controls (QQ = 0.68 ±0.1, QR = 1.07 ±0.11 and RR = 4.89 ±2.84) (p < 0.0001).

Conclusions

PON1 192R allele represents an independent risk factor for early-onset AMI in Egyptians, and PON1 Q192R polymorphism modulates the paraoxonase phenotype.     

Predictors of repeat transarterial chemoembolization in the treatment of hepatocellular carcinoma

ObjectivesRepeat transarterial chemoembolization (TACE) is a common intervention performed for hepatocellular carcinoma (HCC). The aim of this study was to identify predictors of the need for repeat TACE.MethodsBetween 2008 and 2012, data on patient and tumour variables were collected for 262 patients treated with a first TACE procedure for HCC. The decision to perform repeat TACE procedures was made at the completion of the first TACE or after follow-up imaging demonstrated the subtotal treatment of HCC tumours.ResultsRepeat TACE was performed in 67 of 262 (25.6%) patients. Necrosis of HCC, measured after the first TACE, was lower in patients who subsequently received repeat TACE (P = 0.042). On multivariable analysis, total tumour diameter of >5 cm [odds ratio (OR) 2.76, 95% confidence interval (CI) 1.45–5.25; P = 0.002] and increasing age (OR 1.04/year, 95% CI 1.00–1.07; P = 0.030) were predictive of the need for repeat TACE. Measures of liver function and TACE approach (selective versus non-selective) were not predictive of repeat TACE. Median survival did not differ significantly between patients who did (median survival: 21.1 months) and did not (median survival: 26.1 months) receive a repeat TACE procedure (P = 0.574).ConclusionsThe requirement for repeat TACE is associated with older age, increased HCC tumour burden and subtotal TACE-induced HCC necrosis. Importantly, repeat TACE was not associated with reduced survival.