Paraoxonase Arg 192 allele is an independent risk factor for three-vessel stenosis of coronary artery disease

The role of the paraoxonase (PON1) codon 192 polymorphism [glutamine (Q)/arginine (R)] in coronary artery disease (CAD) is controversial. The aim of the present study was to evaluate whether the PON1 gene polymorphism is an independent risk factor for severity of coronary artery disease in patients from west of Iran. The PON1-Arg-192 genotypes were detected by PCR-RFLP in 414 individuals undergoing their first coronary angiography. Patients were placed into one of two groups: CAD and control without CAD or diabetes. The frequency of PON1-Arg-192 allele was significantly higher in the CAD (23.4 vs. 16%, P = 0.032) than in the control group and there was a higher risk of developing CAD (OR = 1.6, P = 0.02). In addition, this difference remained significant after adjustment for without history of diabetes (OR = 1.47, P = 0.048), presence of normolipidemia and absence of history of blood pressure (OR = 1.4, P = 0.05). This result indicated PON1-Arg-192 allele is a risk factor of CAD also when correcting for conventional risk factors. We found a significant association between the PON1-Arg-192 genotype (QR + RR) and the extent of CAD in CAD patients and CAD subjects without diabetes, represented by the increased frequency of three-vessel disease with OR = 1.49, P = 0.046; χ2 = 3.82, P = 0.048 and OR = 1.46, P = 0.05; χ2 = 3.48, P = 0.051, respectively. The CAD patients carrying PON1-Arg-192 genotype (QR + RR) had lower plasma HDL-C level (P = 0.019) and higher plasma LDL-C(P = 0.01) and TG(P = 0.05). Our results indicated that PON1-Arg-192 allele can be important independent risk factor of CAD in a west population of Iran, with carriers of PON1-Arg-192 having an increased frequency of three-vessel disease and also having a distinct plasma lipids profile. Larger collaborative studies are needed to confirm these results.     

Investigating paraoxonase-1 gene Q192R and L55M polymorphism in patients with renal cell cancer

Increased oxidative stress can help promote carcinogenesis, including development of renal cell carcinoma. The enzyme protects low-density lipoproteins from oxidation and can be a factor in this process. PON1 Q192R and L55M paraoxonase gene polymorphisms were assessed in 60 renal cell carcinoma patients and 60 healthy controls. Genotypes were examined by PCR; the restriction enzyme AlwI was used to examine the Q192R polymorphism and Hsp92II for the L55M polymorphism. Significant differences in the PON1 Q192R polymorphism were found between patients and controls. The Q allele was more frequent in the patient group than in controls, while the R allele was more frequent in the control group. No significant differences were found in the L55M polymorphism. Additionally, there were no significant differences in L and M allele frequencies. We conclude that the R allele may protect against renal cell carcinoma.     

First survey of the three gene polymorphisms (PON1 Q192R, eNOS E298D and eNOS C-786T) potentially associated with coronary artery spasm in African populations and comparison with worldwide data

Three polymorphisms, Paraoxonase 1 (PON1) Q192R (C/G), endothelial nitric oxide synthase (eNOS) E298D (G/T) and eNOS T‐786C have been suggested to be potentially associated with coronary artery spasm in Japanese patients. Data on worldwide populations are needed to clarify whether these associations could hold true for other populations. However, few data are available especially in Africans, spasm of which has been suggested to be an aetiology of myocardial infarction. Therefore, these polymorphisms were investigated in three Africans, Ovambos (n = 123), Ghanians (n = 118) and Xhosas (n = 96), together with Japanese (n = 96), by using polymerase chain reaction‐restriction fragment length polymorphism analysis. Genotype‐distributions of all these SNPs in African populations were significantly different from those in Caucasians, whereas were similar to those in Japanese population. African populations exhibit relatively higher frequency of spasm‐associated G192 allele in PON1 Q192R being similar to Japanese population, however frequencies of spasm‐associated T298 allele and –C786 allele in SNP eNOS E298D and T‐786C, respectively, were conversely lower in Africans than Caucasians. Although healthy subjects have been recruited in this study, these findings may provide genetic background for elucidation of aetiology of spasm. Copyright © 2011 John Wiley & Sons, Ltd.     

A preliminary study of human paraoxonase and PON 1 L/M55–PON 1 Q/R 192 polymorphisms in Turkish patients with coronary artery disease

Paraoxonase 1 (PON 1) is a high‐density lipoprotein (HDL)‐associated enzyme with antioxidant function protecting low‐density lipoprotein (LDL) from oxidation. PON 1 has two amino acid polymorphisms in coding region; L/M 55 and Q/R 192. These polymorphisms modulate paraoxonase activity of the enzyme. PON 1 activity decreases in coronary artery disease (CAD). In the present study, distribution of PON 1 L/M 55 and Q/R 192 polymorphisms and the effect of these polymorphisms on the activities of PON 1, and on the severity of CAD in 277 CAD (+) patient and 92 CAD (?) subjects were examined. PON 1 L/M 55 and Q/R 192 genotypes were determined by PCR, RFLP and agarose gel electrophoresis techniques. Genotype distributions and allele frequencies for PON 1 Q/R 192 polymorphism were not significantly different between controls and CAD (+) patient group (p > 0.05), but in genotype and allele distribution of PON 1 L/M55 polymorphism, there was significantly difference among groups (p < 0.05). Genotype distributions for both polymorphisms were not significantly different between subgroups of single‐vessel disease (SVD), double‐vessel disease (DVD) and triple‐vessel disease (TVD). Serum PON 1 activity was lower in CAD (+) group than in controls and this was also statistically significant (p < 0.001). In both groups, the highest PON activities were detected in LL and RR genotypes. In summary, our results suggest that there is an association between the PON 1 L/M 55 polymorphism of paraoxonase and CAD in Turkish patients but not with PON 1 Q/R 192 polymorphism. However, it is hard to correlate these polymorphisms and severity of CAD. Copyright © 2009 John Wiley & Sons, Ltd.     

Paraoxonase 1 192 and 55 polymorphisms in osteosarcoma

Paraoxonase is an HDL-associated enzyme that plays a preventive role against oxidative stres. Previous studies suggested that involved an amino acid substitution at position 192 gives rise to two alloenzymes with a low activity (Q allele) and a high activity (R allele) towards paraoxon. There also exists a second polymorphism of the human PON1 gene affecting amino acid 55, giving rise to a leucine (L-allele) substitution for methionine (M-allele). PON1 gene polymorphisms were studied in 50 patients with osteosarcoma and 50 healthy controls. Paraoxonase genotypes were determined by PCR–RFLP. We found a reduction in the frequency of PON1 192 R allele in patients (P = 0.015). Besides, PON1 192 wild type QQ genotype (P = 0.015) and PON1 55 wild type L allele (P = 0.001) were higher in patients compared to healthy controls. PON1 192 QQ genotype was associated with osteosarcoma in multivariate logistic regression analysis. Our findings have suggested that PON1 192 wild type genotypes may be associated with a risk of developing osteosarcoma.     

Paraoxonase 1 gene polymorphisms and enzyme activities in diabetes mellitus

Paraoxonase 1 (PON1), an antioxidant enzyme closely associated with HDL (high-density lipoproteins), preserves LDL (low-density lipoproteins) against oxidation. Less protection may be therefore supposed by decreased PON1 activity. This study was undertaken to investigate the association of PON1 gene polymorphisms with diabetic angiopathy and to evaluate the relationship of these polymorphisms with PON1 activity. Total of 86 Type 1 (T1DM) and 246 Type 2 (T2DM) diabetic patients together with 110 healthy subjects were examined. DNA isolated from leukocytes was amplified with polymerase chain reaction (PCR) followed by restriction enzyme digestion. The products were analyzed for L55M and Q192R polymorphisms in coding region and for -107 C/T and -907 G/C in promotor sequence of PON1. Serum enzyme activity was measured spectrophotometrically. Significant differences were found between T1DM or T2DM and control persons in L55M polymorphism (allele M more frequent in T1DM and T2DM vs. controls, p<0.05) and Q192R polymorphism (R allele less frequent in T1DM and T2DM vs. controls, p<0.01) of the PON1 gene. Serum PON1 activity was significantly decreased in T1DM (110+/-68 nmol/ml/min) and T2DM patients (118+/-69 nmol/ml/min) compared to the control persons (203+/-58 nmol/ml/min), both p<0.01. The presence of MM and QQ genotypes was accompanied by lower PON1 activity than of LL and RR genotypes (p<0.05), respectively. Better diabetes control was found in patients with LL than with MM genotypes and similarly in RR genotype than QQ genotype with p<0.05. Significantly different allele frequencies were found in diabetic patients with macroangiopathy than in those without it (M: 0.59 vs. 0.44. R: 0.12 vs. 0.19, p<0.01). The association of PON1 polymorphisms, lower PON1 activity and poorer diabetes control found in patients with macroangiopathy further support the idea of genetic factors contributing to the development of vascular disorders in diabetes.     

Paraoxonase (PON1) 55 and 192 polymorphism and its effects to oxidant-antioxidant system in turkish patients with type 2 diabetes mellitus

Paraoxonase (PON1) is a serum enzyme with an antioxidant function, protecting the low density lipoproteins (LDL) from oxidative modifications. Because diabetic patients are at greater risk of oxidative stress, we investigated the effect of PON1 55 methione (M)/leucine (L) and PON1 192 glutamine (A)/arginine (B) polymorphisms on oxidant-antioxidant system in 213 individuals with type 2 diabetes mellitus and 116 non-diabetic control subjects from Turkish population were included in the study. Polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP), and agarose gel electrophoresis techniques were used to determine the PON1 genotypes. Thiobarbituric acid reactive substances (TBARS), conjugated dienes levels in the serum and glutathione (GSH) levels in whole blood were measured spectrophotometrically. In both groups PON1 192 AA and PON1 55 MM genotypes had higher TBARS, conjugated dienes levels and lower GSH levels, whereas PON1 192 BB and PON1 55 LL genotypes had lower TBARS, conjugated diene levels and higher GSH level than other genotypes. We thus conclude that PON1 192 BB and PON1 55 LL alleles have protective effect against oxidative stress.     

Relationships between PON1 Q192R polymorphism and clinical outcome of antiplatelet treatment after percutaneous coronary intervention: a meta-analysis

This meta-analysis was performed to assess the relationships between the PON1 Q192R (rs662 T>C) polymorphism and the clinical outcome of antiplatelet treatment after percutaneous coronary intervention (PCI). A range of electronic databases were searched: Web of Science (1945–2013), the Cochrane Library Database (Issue 12, 2013), PubMed (1966–2013), EMBASE (1980–2013), CINAHL (1982–2013) and the Chinese Biomedical Database (CBM) (1982–2013) without language restrictions. Meta-analysis was conducted using the STATA 12.0 software. The crude odds ratio (OR) with their 95 % confidence interval (CI) were calculated. Six clinical cohort studies with a total number of 5,189 patients undergoing PCI for coronary heart disease were included. Our meta-analysis revealed that the PON1 Q192R polymorphism was correlated with an increased risk of major adverse cardiovascular events (MACE) in patients receiving antiplatelet treatment after PCI (C allele vs. T allele: OR = 1.22, 95 % CI 1.04–1.43, P = 0.014; CT+CC vs. TT: OR = 1.38, 95 % CI 1.03–1.86, P = 0.029; CC vs. TT: OR = 1.45, 95 % CI 1.05–1.99, P = 0.024; respectively), especially among Asians. Furthermore, we found significantly positive correlations between the PON1 Q192R polymorphism and the incidence of stent thrombosis in patients receiving antiplatelet treatment after PCI (C allele vs. T allele: OR = 1.42, 95 % CI 1.08–1.87, P = 0.011; CT+CC vs. TT: OR = 1.93, 95 % CI 1.01–3.67, P = 0.046; CC vs. TT: OR = 2.18, 95 % CI 1.09–4.35, P = 0.027; respectively). Our meta-analysis of clinical cohort studies provides evidence that the PON1 Q192R polymorphism may increase the risk of MACE and stent thrombosis in patients receiving antiplatelet treatment after PCI.     

PON基因簇潜在功能多态位点与冠心病的关联研究

在中国汉族人群PON基因簇序列筛查研究基础上,系统探讨PON基因簇所有潜在功能多态位点与国人冠心病的关系,以期明确PON基因簇序列变异是否国人冠心病的遗传危险因素。随机入选1997～1999年期间阜外心血管病医院病房收治的经冠状动脉造影确诊和/或有明确急性心肌梗塞病史男性冠心病患者474例及年龄(±2岁)匹配的男性健康对照475例。PCR产物直接测序法鉴定PON1基因-1076A/G、-908G/C、-831G/A、-162G/A、-126G/C和-107C/T多态基因型;等位基因特异性扩增方法鉴定PON2基因的A148G和S311C多态;PCR RFLP方法鉴定PON1基因R160G、Q192R和PON3基因-133C/A多态。单变量分析显示192Q, 160R,-162A和311C等位基因频率在病例组中显著高于对照组。以这4个多态性位点作为自变量的多元Logis tic回归分析发现仅R160G和-162G/A多态仍然与冠心病显著关联(P值分别为0.0054和0.0002),并独立于冠心病传统危险因素。不同多态组合的单体型分析进一步证实了单一SNP分析的结果,只有包含160R或-162A 等位基因的单体型在病例组中的频率显著高于对照组。中国北方汉族人群中,PON1基因-162G/A和R160G多态与冠心病独立关联,提示PON1基因可能是冠心病易感基因。     

Paraoxonase (PON)1 Q192R functional genotypes and PON1 Q192R genotype by smoking interactions are risk factors for the metabolic syndrome,but not overweight or obesity

Abstract

Background

The metabolic syndrome (MetS) is a complex of multiple risk factors that contribute to the onset of cardiovascular disorder, including lowered levels of high-density lipoprotein (HDL) and abdominal obesity. Smoking, mood disorders, and oxidative stress are associated with the MetS. Paraoxonase (PON)1 is an antioxidant bound to HDL, that is under genetic control by functional polymorphisms in the PON1 Q192R coding sequence.

Aims and methods

This study aimed to delineate the associations of the MetS with plasma PON1 activity, PON1 Q192R genotypes, smoking, and mood disorders (major depression and bipolar disorder), while adjusting for HDL cholesterol, body mass index, age, gender, and sociodemographic data. We measured plasma PON1 activity and serum HDL cholesterol and determined PON1 Q192R genotypes through functional analysis in 335 subjects, consisting of 97 with and 238 without MetS. The severity of nicotine dependence was measured using the Fagerström Nicotine Dependence Scale.

Results

PON1 Q192R functional genotypes and PON1 Q192R genotypes by smoking interactions were associated with the MetS. The QQ and QR genotypes were protective against MetS while smoking increased metabolic risk in QQ carriers only. There were no significant associations between PON1 Q192R genotypes and smoking by genotype interactions and obesity or overweight, while body mass index significantly increased MetS risk. Smoking and especially severe nicotine dependence are significantly associated with the MetS although these effects were no longer significant after considering the effects of the smoking by PON1 Q192R genotype interaction. The MetS was not associated with mood disorders, major depression or bipolar disorder.

Discussion

PON1 Q192R genotypes and genotypes by smoking interactions are risk factors for the MetS that together with lowered HDL and increased body mass and age contribute to the MetS.     

Association between paraoxonase-1 gene Q192R and L55M polymorphisms and risk of gastric cancer: A case-control study from Iran

The aim of the present study was to examine the relation between two paraoxonase1 (PON1) polymorphisms, Q192R and L55M and susceptibility to gastric cancer in an Iranian population. In this case-control study the PON1 polymorphisms were assessed in 90 gastric cancer patients and 90 healthy controls by polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) method. Regarding PON1 Q192R polymorphism, a significant increase in the R allele in the patient group compared with the controls (p value?=?0.0006) While the Q allele was more frequent in the control group. No significant difference was found in the genotype or allele frequency of the L55M polymorphism between healthy individuals and patients with gastric cancer. Our results demonstrated the protective effect of Q allele against gastric cancer.     

European versus Asian differences for the associations between paraoxonase‐1 genetic polymorphisms and susceptibility to type 2 diabetes mellitus

Many studies have examined the associations between paraoxonase‐1 (PON1) genetic polymorphisms (Q192R, rs662 and L55M, rs854560) and the susceptibility to type 2 diabetes mellitus (T2DM) across different ethnic populations. However, the evidence for the associations remains inconclusive. In this study, we performed a meta‐analysis to clarify the association of the two PON1 variants with T2DM risk. We carried out a systematic search of PubMed, Embase, CNKI and Wanfang databases for studies published before June 2017. The pooled odds ratios (ORs) for the association and their corresponding 95% confidence intervals (CIs) were calculated by a random‐ or fixed‐effect model. A total of 50 eligible studies, including 34 and 16 studies were identified for the PON1 Q192R (rs662) and L55M (rs854560) polymorphism, respectively. As for the PON1 Q192R polymorphism, the 192R allele was a susceptible factor of T2DM in the South or East Asian population (OR > 1, P < 0.05) but represented a protective factor of T2DM in European population (OR = 0.66, 95% CI = 0.45–0.98) under a heterozygous genetic model. With regard to the PON1 L55M polymorphism, significant protective effects of the 55M allele on T2DM under the heterozygous (OR = 0.77, 95% CI = 0.61–0.97) and dominant (OR = 0.80, 95% CI = 0.65–0.99) genetic models were found in the European population, while no significant associations in the Asian populations under all genetic models (P > 0.05). In summary, by a comprehensive meta‐analysis, our results firmly indicated that distinct effects of PON1 genetic polymorphisms existed in the risk of T2DM across different ethnic backgrounds.     

R-carrying genotypes of serum paraoxonase (PON1) 192 polymorphism and higher activity ratio are related to susceptibility against ischemic stroke

The polymorphic gene of serum paraoxonase (PON1) and its activity involved in atherosclerosis. The purpose of the study was to analyze PON1 192 Q/R polymorphism and the enzyme activities in ischemic stroke. The polymorphism as the most common polymorphism in PON1 gene coding sequence is associated with variation in the enzyme activity and vascular disease. The study included 85 stroke patients and 71 control subjects. PON1 192 polymorphism was genotyped using PCR protocol. Paraoxonase activity (Para) and arylesterase activity (Aryl) were determined spectrophotometrically using paraoxon and phenylacetate as the substrates. The QR and RR genotypes were more frequent in stroke population compared to controls, resulting in a higher frequency of the R allele in patients (0.24 vs 0.18, OR?=?1.41). Patients had significantly higher Para/Aryl ratio than that of controls (P?=?0.016). In stroke patients, Para/Aryl and Para/HDL ratios increased with this order: QQ?<?QR?<?RR. Hypertension significantly increased the risk of ischemic stroke by 15-fold among R-containing people, while this was significantly increased 4-fold for QQ homozygotes. Smoking increased the risk of having ischemic stroke in both QQ homozygote and QR?+?RR group (OR?=?2.84 and OR?=?2.33, respectively). In conclusion, these data highlight the importance of PON1 192 R allele and high Para/Aryl ratio in susceptibility to ischemic stroke in the population. The presence of the 192 R allele potentiates the risk of stroke especially in hypertensive people. Decreased Aryl and increased Para/Aryl, Para/HDL and Aryl/HDL ratios may be markers indicated the increased susceptibility to ischemic stroke in the population.     

Q192R polymorphism in the PON1 gene and nasal polyp in a Turkish population

The pathogenesis of nasal polyps is not completely understood. Oxidative damage contributes to polyp formation in the nasal mucosa. The paraoxonase 1 (PON1) enzyme is an important liver enzyme with high antioxidant activity. In this study, we investigated the correlation between Q192R genotypic polymorphism of the PON1 enzyme and nasal‐polyp disease. The study examined 62 nasal‐polyp patients and 88 controls. PON1 Q192R polymorphism was determined using polymerase chain reaction‐restriction fragment length polymorphism. The genotype distribution of the PON1 gene was significantly different between nasal‐polyp patients (QQ = 69.35%, QR = 25.81%, RR = 4.83%) and healthy controls (QQ = 52.27%, QR = 44.31%, RR = 3.40%). Our results suggest that the PON1 QQ genotype (odds ratio [OR] = 2.066, P = .036) is associated with a higher risk of developing the nasal‐polyp disease while QR genotype (OR = 0.437, P = .021) showed a lower risk.     

Paraoxonase 1 polymorphisms L55M and Q192R were not risk factors for Parkinson's disease: a HuGE review and meta-analysis

Purpose

The Paraoxonase 1 (PON1) has been studied as a potential candidate gene for Parkinson's disease risk, but direct evidence from genetic association studies remains inconclusive. We performed a meta-analysis pooling data from all relevant studies in order to determine the effects of two PON 1 polymorphisms (L55M and Q192R) on Parkinson's disease.

Methods

We applied a random effects to combine odds ratio (OR) and 95% confidence intervals. Q statistic was used to evaluate the homogeneity, and Egger's test and Funnel plot were used to assess publication bias. In secondary analyses, we examined dominant and recessive models as well.

Results

Concerning the PON1 L55M polymorphism, we identified 9 eligible studies (a total of 2582 cases and 3997 controls). The random effects pooled OR was OR = 1.29, (0.90, 1.84). Concerning the Q192R polymorphism, we identified 7 eligible studies (a total of 2582 cases and 3997 controls). The random effects pooled OR was OR = 1.08(0.81, 1.43). Analysis with dominant and recessive genetic models yielded the same inferences as genotype-based comparisons for both of the two polymorphisms.

Conclusion

The results of this meta-analysis suggested that both PON1 L55M and Q192R were not responsible for PD.     

PON1 55/192 polymorphism, oxidative stress, type, prognosis and severity of stroke

We investigated the association of PON1 55/192 polymorphisms with type, severity and prognosis of stroke and oxidative markers. Paraoxonase1 (PON1), Glutathione Reductase (GSH-Rd) and Malondialdehyde (MDA) levels were measured at day 1 and at day 5 following the onset of stroke. Genotypes were determined by polymerase chain reaction and restriction digestion. The frequencies of QQ and MM genotypes of PON1 192 and PON1 55, respectively, were significantly higher in controls than in patients. However, the allele frequencies of PON1 192 R and PON1 55 L were significantly more frequent in patients compared to controls. The frequency of combined genotype of RR/LL was significantly higher in cardioembolic group than in atherothrombotic group. PON1 activities were significantly diminished in stroke patients compared to controls. In contrast, serum MDA levels were significantly greater in patients than the values in controls. GSH-Rd activity was higher in patients with small lesion and good prognosis than those with large and poor prognosis. Low density lipoprotein (LDL) levels in patients with large lesions were higher than those with small lesions. PON1 55/192 polymorphisms influence activity of the enzyme. PON1 55/192 genotypes have been associated with MDA levels. In conclusion, PON1 genetic variations are associated with risk factors, severity, type and prognosis of stroke and oxidative stress.     

Paraoxonase1-192 polymorphism modulates the effects of regular and acute exercise on paraoxonase1 activity

Regular exercise practise is a protective factor against coronary heart disease and enhances antioxidant systems, whereas acute exercise appears to be a major source of increased oxidative stress. Paraoxonase1 (PON1) is an antioxidant HDL-linked enzyme, whose activity toward paraoxon (PON1 activity) is strongly modulated by the PON1-192 polymorphism, comprising Q and R alleles for low and high PON1 activity, respectively. Another polymorphism at the PON1 locus, the PON1-55, modulates PON1 protein and activity levels. PON1 activity, lipid levels, and oxidized LDL concentration were determined in 17 healthy young volunteers before and after a 16-weeks aerobic exercise training period. Furthermore, PON1 activity was analyzed after a bout of exercise in both situations. We found that regular exercise was associated with a decrease in oxidized LDL levels, and an increase in PON1 activity in QQ subjects and with a decrease in PON1 activity in R carriers. A bout of exercise produced an increase in PON1 activity just after the bout of exercise, followed by a decrease in its activity. A recovery of the basal PON1 activity levels at 24 h was found in QQ subjects regardless of their training status and in trained R carriers, but not in untrained R carriers. These results suggest that the effects of regular and acute exercise on PON1 activity levels are modulated by PON1-192 polymorphism. Changes were less evident for the PON1-55 polymorphism.     

The 192R/Q polymorphs of serum paraoxonase PON1 differ in HDL binding, lipolactonase stimulation, and cholesterol efflux

Serum paraoxonase (PON1) is a HDL-associated enzyme exhibiting potentially antiatherogenic properties. Here, we examined the common PON1-192R/Q human polymorphism. Despite numerous studies, the effect of this polymorphism on the antiatherogenic potential of PON1 is yet unresolved. Our structural model suggests that amino acid 192 constitutes part of the HDL-anchoring surface and active site of PON1. Based on our findings that PON1 is an interfacially activated lipolactonase that selectively binds HDL carrying apolipoprotein A-I (apoA-I) and is thereby greatly stabilized and catalytically activated, we examined the interaction of the PON1-192 isozymes with reconstituted HDL-apoA-I particles. We found that PON1 position 192 is indeed involved in HDL binding. The PON1-192Q binds HDL with a 3-fold lower affinity than the R isozyme and consequently exhibits significantly reduced stability, lipolactonase activity, and macrophage cholesterol efflux. We also observed the lower affinity and stability of the 192Q versus the 192R isozyme in sera of individuals belonging to the corresponding genotypes. The observed differences in the properties of PON1-192R/Q isozymes provide a basis for further analysis of the contribution of the 192R/Q polymorphism to the susceptibility to atherosclerosis, although other factors, such as the overall levels of PON1, may play a more significant role.     

Paraoxonase 1 gene polymorphism 192Q/R in old men and long-livers from Tatars ethnic group

Comparison in genotype and allele frequencies of people groups of younger (from 1 till 20 years), middle (21-55 years), elderly (56-74 years), senile (75-89 years) age and long-livers (90-109 years) have been performed (only 1116 person) with the purpose of analysis of molecular-genetic bases of ageing and longevity of the person. Allele variants of PON1 gene have been identified by polymerase chain reaction in a combination with restriction analysis. In the general sample of Tatars genotypes PON1*Q/*Q, PON1*Q/*R and PON1*R/*R are revealed with frequencies of 46.15, 44.35 and 9.5%, alleles PON1*Q and PON1*R are found with frequencies of 68.32 and 31.68% accordingly. Statistically significant distinctions on frequencies of genotypes and alleles between separate age groups are found. It has appeared, that frequency of PON1*R allele (28.46%) is lowered among old men in comparison with those among persons of younger age (37.42%, P = 0.009). However essentially above in group of long-livers, than in group of old men, frequencies allele PON1*R (P = 0.005) and genotype PON1*R/*R (P = 0.01).     

Differential effects of paraoxonase 1 (PON1) polymorphisms on cancer risk: evidence from 25 published studies

Paraoxonase is an HDL-associated enzyme that plays a preventive role against oxidative stress, which is thought to contribute to cancer development. PON1 activity varies widely among individuals, which is in part related to two common nonsynonymous polymorphisms in the PON1 gene (Q192R and L55M). The polymorphisms in PON1 have been implicated in cancer risk. However, results from the studies to date have been conflicting. To clarify the association, a meta-analysis was performed for 7,073 cases and 9,520 controls from 25 published case–control studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the association. Significant associations between PON1-L55M but not Q192R polymorphism and total cancer were observed from all the comparisons. In stratified analyses, PON1-55M allele was a risk factor for breast cancer. Similarly, increased risk was observed for prostate cancer (OR = 1.18, 95% CI: 1.01–1.36, P _{heterogeneity} = 0.260) and Caucasian population (OR = 1.18, 95% CI: 1.02–1.38, P _{heterogeneity} = 0.1) of the LM genotype, compared with the LL genotype. For PON1-Q192R polymorphism, PON1-192R allele was a decreased risk factor for cancer in the Asian group (RR vs QQ: OR = 0.61, 95% CI: 0.38–0.98, P _{heterogeneity} = 0.268; QR vs QQ: OR = 0.71, 95% CI: 0.52–0.96, P _{heterogeneity} = 0.130; RR + QR vs QQ: OR = 0.71, 95% CI: 0.53–0.95, P _{heterogeneity} = 0.135). Although some modest bias could not be eliminated, this meta-analysis suggests that the PON1-55M allele is a risk factor for the development of cancer, in particular for breast cancer. Future studies with larger sample sizes are warranted to further evaluate these associations.