This Article Abstract Full Text (PDF) All Versions of this Article: 107/22/2775    most recent 01.CIR.0000070954.00271.13v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Mackness, B. Articles by Mackness, M. Search for Related Content PubMed PubMed Citation Articles by Mackness, B. Articles by Mackness, M. Pubmed/NCBI databases Gene GEO Profiles HomoloGene UniGene Compound via MeSH Substance via MeSH Related Collections Lipid and lipoprotein metabolism Pathophysiology Risk Factors

(Circulation. 2003;107:2775.)
© 2003 American Heart Association, Inc.

Clinical Investigation and Reports

Low Paraoxonase Activity Predicts Coronary Events in the Caerphilly Prospective Study

Bharti Mackness, PhD; Paul Durrington, FMedSci; Patrick McElduff, PhD; John Yarnell, PhD; Naheed Azam, BSc; Michael Watt, BSc; Michael Mackness, PhD

From the University Department of Medicine (B.M., P.D., N.A., M.W., M.M.), Manchester Royal Infirmary; School of Epidemiology and Public Health (P.M.), University of Manchester; and Department of Epidemiology and Public Health (J.Y.), Queen’s University Belfast, UK.

Correspondence to Michael Mackness, PhD, University Department of Medicine, Manchester Royal Infirmary, Oxford Rd, Manchester M13 9WL, UK. E-mail mike.mackness{at}cmmc.nhs.uk

	Abstract

Top Abstract Introduction Methods Results Discussion References

 
Background— The hypothesis that paraoxonase (PON1) has a role in preventing atherosclerosis is based on experimental, transgenic, and case-control studies but has not previously been tested prospectively.

Methods and Results— The Caerphilly Prospective Study is a cohort study of men aged 49 to 65 years observed for coronary heart disease (CHD) events (fatal and nonfatal myocardial infarction) over a mean period of 15 years. Serum PON1 activity toward paraoxon was measured in 1353 participants. PON1 activity was 20% lower in the 163 men who had a coronary event (P=0.039). Men in the highest quintile of PON1 activity had a decreased risk compared with those in the lowest quintile (OR 0.57 [95% CI, 0.33 to 0.96]). The inverse relationship between quintiles of serum PON1 activity and CHD risk was graded, the median change in OR across each quintile being 0.87 (0.77 to 0.98). After adjustment for all other CHD risk factors, including HDL cholesterol, this median value became 0.90 (0.78 to 1.02). PON1 was most predictive of a new CHD event in patients at highest risk by virtue of preexisting CHD (adjusted median OR for each quintile, 0.74 [0.59 to 0.93]; n=313) or the presence of other risk factors. For the highest tertile of CHD risk (n=390) calculated by the Framingham equation, adjusted median OR for each quintile was 0.84 (0.66 to 1.05); n=390.

Conclusions— Low serum PON1 activity toward paraoxon is an independent risk factor for coronary events in men at high risk because of preexisting disease or other CHD risk factors.

Key Words: myocardial infarction • lipoproteins • coronary disease • antioxidants

	Introduction

Top Abstract Introduction Methods Results Discussion References

 
Paraoxonase (EC.3.1.8.1, aryldialkylphosphatase) (PON1) has been extensively studied in the field of toxicology because it hydrolyses organophosphate compounds, used as insecticides and nerve gases.^1,2 PON1 is synthesized in the liver and in serum is located on HDL. The serum HDL concentration is inversely correlated with atherosclerosis risk.³ The mechanism for this continues to be the subject of considerable debate. The initial focus of attention was on the role of HDL in reverse-cholesterol transport. However, recent studies have suggested more diverse mechanisms. HDL protects against oxidative modification of LDL,^4–6 which is believed to be central to the initiation and progression of atherosclerosis.⁷ The antioxidant activity of HDL relates to its enzymes, primarily PON1, but also LCAT,⁸ and these can prevent lipid-peroxide accumulation on LDL both in vitro and in vivo.^9–14

PON1 activity is partly genetically determined. An amino acid substitution at position 192 (QR) gives rise to 2 allozymes,^15,16 the relative activities of which are substrate dependent. Substrates, such as paraoxon and fenitroxon, are hydrolyzed faster by the R alloenzyme, whereas other substrates, such as phenyl acetate, are hydrolyzed at the same rate by both alloenzymes, and yet others, such as diazoxon and the nerve gases soman and sarin, are hydrolyzed more rapidly by the Q alloenzyme.¹⁷ The Q alloenzyme in vitro provides greater protection against the accumulation of lipid peroxides on LDL than the R alloenzyme.^18,19 A second exonic polymorphism of the PON1 gene occurs at amino acid position 55 (LM). This polymorphism also affects PON1 activity, although less than that of the 192 polymorphism.²⁰

There have been many case-control studies to test the hypothesis that the 192R allele of the PON1 gene is associated with coronary heart disease (CHD).²¹ A recent meta-analysis of these found that the PON1-192R allele was significantly related to the presence of CHD, but there was evidence of publication bias.²² Furthermore, genetic case-control studies fail to test the hypothesis that serum PON1 activity protects against CHD, because the 192 polymorphism accounts for only a small part of the 40-fold individual variation in serum PON1 activity.

Only 5 case-control studies have included measurements of PON1 activity as opposed to relying on genotype alone.^22–26 In one of these, diminished protection of LDL against oxidation by HDL from patients with coronary atherosclerosis was reported,²⁴ which, it was proposed, was attributable to low serum PON1 activity. In another study we found that serum PON1 activity was already decreased within 2 hours of the onset of symptoms of acute myocardial infarction²⁵ and remained low subsequently, suggesting that the decreased activity may have preceded the acute event.²⁵ Furthermore, the lower activity in the patients with myocardial infarction compared with controls was substantially greater than could be accounted for by PON1 polymorphisms. Two recently conducted large case-control studies in which PON1 activity and genotype were measured in people with angiographically proven CHD and controls also concluded that serum PON1 activity was more closely related to the presence of CHD than the PON1-192 genotype.^22,26

Case-control studies can give misleading results because of survivor effects, bias in case selection, and the effect of the disease and its treatment. It is thus important that the association of PON1 activity and CHD be tested prospectively. We therefore studied the relationship between new coronary events in the Caerphilly Prospective Study and serum PON1 activity with the specific a priori hypothesis that PON1 activity would be related to CHD. We also measured serum PON1 concentration and clusterin (apolipoprotein J [apoJ]), which has also been proposed as a component of HDL with a role in protecting tissues against oxidative damage.^24,27

	Methods

Top Abstract Introduction Methods Results Discussion References

 
Subjects
The general design and methods of the Caerphilly Prospective Study have been described elsewhere.²⁸ Men aged 49 to 65 years living in Caerphilly (South Wales), randomly selected from the electoral register, were invited to participate between 1984 and 1988. A detailed medical, lifestyle, and family history was obtained, the London School of Hygiene and Tropical Medicine chest pain questionnaire²⁹ was administered, a 12-lead ECG was recorded, and full anthropometric details and fasting blood samples were obtained.

Previously unthawed serum samples stored at -80°C were available from 1353 men. In a pilot study, we analyzed 100 of them randomly chosen for PON1 activity toward paraoxon. Their median activity, 198.1 U/L (96.4 to 407.7), was not significantly different from fresh samples from a Manchester control population (n=281) in which it was 216.1 U/L (76.8 to 517.8). In 40 controls from Manchester, serum PON1 activity at the time samples was taken, and 6 years after storage at -80°C was also not significantly different (170.6 U/L [68.2 to 360.4] and 165.9 U/L [56.6 to 320.9], respectively). Similar comparisons of PON1 and apoJ concentration also revealed no significant differences (results not shown).

The occurrence of a coronary event was monitored over an average of 15 years as described²⁸ and was defined as fatal or nonfatal myocardial infarction or the appearance of major or moderate Q waves (Minnesota codes 1–1-any, 1–2-1 to 1–2-5, or 1–2-7) on any follow-up ECG where there were no Q waves (1–1-any, 1–2-any, 1–3-any) on the recruitment ECG. Preexisting CHD was defined as a history of severe chest pain, a positive history of angina on the chest pain questionnaire, or ischemic changes on the ECG as defined previously.²⁸ Family history of CHD was defined as having at least one first-degree relative with acute myocardial infarction before the age of 55 years.

Analysis of PON1
Serum PON1 activity toward paraoxon was analyzed spectrophotometrically as described previously.²⁰ PON 1 concentration was determined by using our in-house competitive ELISA using rabbit anti-human PON1 monospecific antibodies as described previously.³⁰

Determination of Clusterin Concentration
Clusterin concentration was determined by ELISA using monoclonal antibodies to human clusterin and pure clusterin as standard (both purchased from Quidel, Aalkmar, the Netherlands) as described previously.²² Interassay and intra-assay coefficients of variation were 7.2% and 4.2%, respectively.

Other Laboratory Tests
Methods for serum cholesterol, HDL cholesterol (HDL-C), apoB, apoA1, and triglycerides have been previously described.²⁸

Statistical Analysis
Means were calculated for most variables in men who did and did not have a coronary event. Medians were used for serum triglycerides, total to HDL cholesterol ratio, PON1 activity, PON1 concentration, and clusterin, which were nongaussian. Differences were sought by Student’s t test unless the frequency distribution was nongaussian, when the Mann-Whitney U test was used. Differences in the proportions of men with categorical variables were sought with the ² test.

The independent contribution of quintiles of PON1 to CHD risk expressed as the OR (the median ratio of the proportion of men in 1 quintile who had a CHD event to that in the next) was tested by logistic regression analysis with age, smoking status, preexisting CHD, family history of CHD, body mass index, systolic blood pressure, diastolic blood pressure, diabetes, serum cholesterol, HDL-C, serum triglyceride, and total to HDL cholesterol ratio included as covariates.

	Results

Top Abstract Introduction Methods Results Discussion References

 
The risk factors of the men who did or did not have a new coronary event are given in Table 1. The former had significantly increased systolic and diastolic blood pressure, serum total cholesterol, triglycerides, and apoB, total serum to HDL cholesterol ratio, and likelihood of smoking, preexisting CHD, a family history of CHD, and lower HDL cholesterol, as previously reported.^28,31 Serum PON1 activity was 20% lower in the men experiencing CHD events (P<0.039). PON1 (79.4 µg/mL [2.3 to 275.9] versus 84.6 [3.3 to 447.8] µg/mL median [range]), and clusterin (97.5 [12.6 to 192.7] versus 101.2 [1.0 to 320.5] µg/mL) concentrations in the men who did and did not have a coronary event were not significantly different.

View this table: [in this window] [in a new window]   TABLE 1. Risk Factors in Men Who Did and Did Not Experience a New Coronary Event During the Study and the Median OR for Each Quintile Compared With the Next for Each Risk Factor

There was a graded inverse relationship between quintiles of serum PON1 activity and the likelihood of a CHD event (Figure). Men in the highest quintile of PON1 activity had a decreased likelihood of having a coronary event, OR=0.57 (95% CI, 0.33 to 0.96) (P=0.031) compared with those in the lowest quintile, and the median decrease in risk from each quintile to the next highest was 0.87 (0.77 to 0.98) (P<0.05) (Table 1). The median OR for the likelihood of an event for each successive quintile of PON1 remained statistically significant after adjustment for history of CHD, family history of CHD, smoking, diabetes, body mass index, blood pressure, and total serum cholesterol (Table 2).

View larger version (15K): [in this window] [in a new window]   The relative likelihood (OR) of a new CHD event occurring in the quintiles of serum paraoxonase activity in 1353 men, when quintile 1 has the lowest and quintile 5 has the highest activity. , ORs adjusted for age, family history, smoking, body mass index, history of CHD, diabetes, blood pressure, cholesterol, triglycerides, and HDL-C. , Unadjusted OR.

View this table: [in this window] [in a new window]   TABLE 2. Median OR (95% CIs) for the Likelihood of a CHD Event Between Each Quintile of PON1 Activity and the Next

Adjustment for HDL-C had only a quantitatively small effect on the median OR between successive quintiles of PON1 activity and CHD risk, changing it from 0.87 to 0.89, although its confidence intervals just exceeded unity. PON1 and HDL-C were significantly correlated (P=<0.001), but the correlation coefficient (0.21) was too low to explain the whole of the effect of PON1 activity on CHD risk. Triglycerides correlated with HDL-C (Spearman’s correlation coefficient -0.40; P<0.0001), and addition of these after HDL-C made no difference to the model. When a similar analysis was performed for the predictive power of HDL-C, adjusting for all risk factors except PON1 activity, the OR for HDL was 0.83 (0.72 to 0.95). When PON1 activity was added to the model, HDL-C was relatively unaffected as a risk factor(OR 0.83 [0.76 to 0.96]) for the men overall, although in the men with preexisting CHD, PON1 adjusted for HDL-C was a stronger risk factor than HDL-C adjusted for PON1 (OR, 0.73 [0.58 to 0.92] versus 0.85 [0.69 to 1.05]). These results indicate that both HDL-C and PON1 activity contribute independently to variation in CHD risk.

PON1 was a stronger prognostic factor in the presence of CHD. The gradient between quintiles in the 313 subjects with a definite history of CHD on entry to the study gave an OR of 0.74 (0.59 to 0.93) (P=0.011) after adjustment for all other coronary risk factors including HDL-C, whereas the OR for the 1040 subjects with no history of CHD on entry to the study was 0.98 (0.83 to 1.15) (P=0.769) after adjustment (Table 2). Men with CHD are at greater risk of new CHD events than men without such a history. To examine whether the greater predictive power of PON1 activity was related to the presence of CHD or to their greater risk, we studied those men who had no history of CHD but who were in the highest tertile of CHD risk predicted by the Framingham equation.³² The OR for this group after adjustment for all other risk factors was 0.84 (0.66 to 1.05), indicating a stronger predictive power of PON1 activity than in those without CHD at entry.

	Discussion

Top Abstract Introduction Methods Results Discussion References

 
This is the first prospective epidemiological study of PON1 and CHD. Its results indicate that low serum PON1 activity toward paraoxon is a predictive risk factor for subsequent coronary events independent of all other established risk factors, with the exception of HDL, of which PON1 is a component. However, the erosion of the independent effect of PON1 by HDL-C was small. The correlation of HDL-C with PON1 was weak and certainly not strong enough to explain the whole relationship between PON1 and CHD.

This, together with the results of earlier case-control studies of the PON1-192 polymorphisms, which influence PON1 activity toward paraoxon,²¹ support the view that PON1 has a direct protective effect against CHD. Its capacity to predict coronary events, like its location and activity, is likely to be intimately linked with HDL. This would explain the suggestion from our present findings that PON1 activity and HDL-C are only partially independent CHD risk factors. We and others have shown that PON1 can prevent the oxidation of LDL both in vitro and in vivo. The present findings thus provide evidence in support of the hypothesis that the oxidative modification of LDL is important in the initiation and progression of atherosclerosis.⁷ The protection that the PON1 of HDL affords LDL against lipid peroxidation is substantially more prolonged than that of antioxidant vitamins,⁶ which have been notably unsuccessful in CHD prevention.^33–36

Our finding that PON1 activity was a stronger prognostic factor in the men at highest risk of a new CHD event, either because they already had clinical evidence of CHD or because other risk factors clustered in them as indicated by the Framingham risk equation, is consistent with several case-control studies in which low PON1 activity or PON1 polymorphisms associated with low activity have been reported to be more prevalent in patients at increased risk by virtue of other risk factors such as age, cigarette smoking, hypertension, hyperlipidemia, and diabetes mellitus.^21,37 It suggests that, were it possible to increase PON1 activity by a nutritional or pharmacological intervention,³⁷ the adverse effect of some of other risk factors might be ameliorated.

The lack of any significant association between CHD and PON1 concentration requires explanation. We cannot exclude the possibility that PON1 concentration would have been predictive of coronary events in a larger study than the present one. However, our finding that the higher PON1 concentration was not statistically related to CHD risk, whereas hydrolytic activity toward paraoxon was, would suggest that the differential substrate activity of PON1 may be critical for its protective effect against atherosclerosis, at least within the concentration range encountered in our population. The concentration of the enzymatic catalyst is probably more critical to the reaction rate for hydrolytic activities of PON1, which are rapid, for example, with phenylacetate. The reaction rate with paraoxon (and lipid peroxides) is relatively low,^1,9 and therefore the enzyme concentration may be less critical. Genetic and acquired factors might also influence the active site configuration on PON1 so that PON1 activity may be more critical than concentration in atherogenesis.

A lipid environment is essential for the activity of PON1, because most of its substrates are highly hydrophobic.¹ The lipid composition of HDL, which is open to nutritional or pharmacological modification, may provide a means of modifying PON1 activity favorably. Furthermore, there may be opportunities to increase the expression of PON1 activity by nutritional or pharmacological effects on its genetic regulation³⁷ now that promoter polymorphisms of PON1 have been reported to be associated with early onset CHD.³⁸

Serum clusterin, which is present in the same HDL subspecies as PON1, did not predict new CHD events in this study, nor was it related to the presence of CHD in our previous case-control study.²² It is possible that the results of Navab et al,²⁴ obtained in fewer than 30 patients, were a reflection of an acute rather than chronic elevation, and additional studies should be conducted, specifically designed to test this possibility.

In conclusion, we have shown that low PON1 activity explains a significant proportion of the variation in CHD risk in middle-aged men. These results are likely to be explained by a derangement of PON1 activity toward lipid peroxides, which is reflected in its hydrolytic activity toward paraoxon.

	Acknowledgments

 
This study was supported by the British Heart Foundation. The Caerphilly study was undertaken by the former MRC Epidemiology Unit (South Wales) and was funded by the UK Medical Research Council. The authors thank C. Price for expert preparation of the manuscript.

Received February 21, 2003; accepted March 4, 2003.

	References

Top Abstract Introduction Methods Results Discussion References

 

1. La Du BN. Human serum paraoxonase/arylesterase. In: Kalow W, ed. Pharmacogenetics of Drug Metabolism. New York: Pergamon Press; 1992: 51–91.
   
2. Mackness B, Durrington PN, Mackness MI. Human serum paraoxonase. Gen Pharmacol. 1998; 31: 329–336.[CrossRef][Medline] [Order article via Infotrieve]
   
3. Miller GJ, Miller NE. Plasma high-density lipoprotein concentration and the development of ischaemic heart disease. Lancet. 1975; i: 16–19.
   
4. Parthasarathy S, Barnett J, Fong LG. High-density lipoprotein inhibits the oxidative modification of low-density lipoprotein. Biochim Biophys Acta. 1990; 1044: 275–283.[Medline] [Order article via Infotrieve]
   
5. Ohta T, Takata S, Morino Y, et al. The protective effects of lipoproteins containing apoprotein A-I on Cu²⁺-catalysed oxidation of human low-density lipoprotein. FEBS Lett. 1989; 257: 435–438.[CrossRef][Medline] [Order article via Infotrieve]
   
6. Mackness MI, Abbott CA, Arrol S, et al. The role of high density lipoprotein and lipid-soluble antioxidant vitamins in inhibiting low-density lipoprotein oxidation. Biochem J. 1993; 294: 829–835.
   
7. Steinberg D, Parthasarathy S, Carew TE, et al. Beyond cholesterol modifications of low-density lipoprotein that increase its atherogenicity. N Engl J Med. 1989; 320: 915–924.[Medline] [Order article via Infotrieve]
   
8. Mackness MI, Durrington PN. High density lipoprotein, its enzymes and its potential to influence lipid peroxidation. Atherosclerosis. 1995; 115: 243–253.[CrossRef][Medline] [Order article via Infotrieve]
   
9. Mackness MI, Arrol S, Durrington PN. Paraoxonase prevents accumulation of lipoperoxides in low-density lipoprotein. FEBS Lett. 1991; 286: 152–154.[CrossRef][Medline] [Order article via Infotrieve]
   
10. Mackness MI, Arrol S, Abbott CA, et al. Protection of low-density lipoprotein against oxidative modification by high-density lipoprotein associated paraoxonase. Atherosclerosis. 1993; 104: 129–135.[CrossRef][Medline] [Order article via Infotrieve]
    
11. Watson AD, Berliner JA, Hama SY, et al. Protective effect of high density lipoprotein associated paraoxonase: inhibition of the biological activity of minimally oxidised low-density lipoprotein. J Clin Invest. 1995; 96: 2882–2889.
    
12. Shih DM, Gu L, Xia Y-R, et al. Mice lacking serum paraoxonase are susceptible to organophosphate toxicity and atherosclerosis. Nature. 1998; 394: 284–287.[CrossRef][Medline] [Order article via Infotrieve]
    
13. Aviram M, Billecke S, Sorenson R, et al. Paraoxonase active site required for protection against LDL oxidation involves its free sulphydryl group and is different from that required for its arylesterase/paraoxonase activities: selective action of human paraoxonase alloenzymes Q and R. Arterioscler Thromb Vasc Biol. 1998; 10: 1617–1624.
    
14. Aviram M, Hardak E, Vaya J, et al. Human serum paraoxonase (PON1) Q and R selectively decrease lipid peroxides in human coronary and carotid atherosclerotic lesions: PON1 esterase and peroxidase-like activities. Circulation. 2000; 101: 2510–2517.[Medline] [Order article via Infotrieve]
    
15. Adkins S, Gan KN, Mody M, et al. Molecular basis for the polymorphic forms of human serum paraoxonase/arylesterase: glutamine or arginine at position 191, for the respective A or B allozymes. Am J Hum Genet. 1993; 52: 598–608.[Medline] [Order article via Infotrieve]
    
16. Humbert R, Adler DA, Disteche CM, et al. The molecular basis of the human serum paraoxonase activity polymorphism. Nature Genet. 1993; 3: 73–76.[CrossRef][Medline] [Order article via Infotrieve]
    
17. Davies HG, Richter RJ, Keifer M, et al. The effect of the human serum paraoxonase polymorphism is reversed with diazoxon, soman and sarin. Nature Genet. 1996; 14: 334–336.[CrossRef][Medline] [Order article via Infotrieve]
    
18. Mackness MI, Arrol S, Mackness B, et al. The alloenzymes of paraoxonase determine the effectiveness of high-density lipoprotein in protecting low density lipoprotein against lipid-peroxidation. Lancet. 1997; 349: 851–852.[CrossRef][Medline] [Order article via Infotrieve]
    
19. Mackness B, Mackness MI, Arrol S, et al. Effect of the human serum paraoxonase 55 and 192 genetic polymorphisms on the protection by high density lipoprotein against low density lipoprotein oxidative modification. FEBS Lett. 1998; 423: 57–60.[CrossRef][Medline] [Order article via Infotrieve]
    
20. Mackness B, Mackness MI, Arrol S, et al. Effect of the molecular polymorphisms of human paraoxonase (PON1) on the rate of hydrolysis of paraoxon. Br J Pharmacol. 1997; 112: 265–268.[CrossRef]
    
21. Durrington PN, Mackness B, Mackness MI. Paraoxonase and atherosclerosis. Arterioscler Thromb Vasc Biol. 2001; 21: 473–480.[Abstract/Free Full Text]
    
22. Mackness B, Davies GK, Turkie W, et al. Paraoxonase status in coronary heart disease: are activity and concentration more important than genotype? Arterioscler Thromb Vasc Biol;. 2001; 21: 1451–1457.[Abstract/Free Full Text]
    
23. McElveen J, Mackness MI, Colley CM, et al. Distribution of paraoxon hydrolysing activity in the serum of patients after myocardial infarction. Clin Chem. 1986; 32: 671–673.[Abstract/Free Full Text]
    
24. Navab M, Hama-Levy S, Van Lenten BJ, et al. Mildly oxidised LDL induces an increased apolipoprotein J/paraoxonase ratio. J Clin Invest. 1997; 99: 2005–2019.[Medline] [Order article via Infotrieve]
    
25. Ayub A, Mackness MI, Arrol S, et al. Serum paraoxonase after myocardial infarction. Arterioscler Thromb Vasc Biol. 1999; 19: 330–335.[Abstract/Free Full Text]
    
26. Jarvik GP, Rozek LS, Brophy VH, et al. Paraoxonase (PON1) phenotype is a better predictor of vascular disease than is PON1₁₉₂ or PON1₅₅ genotype. Arterioscler Thromb Vasc Biol. 2000; 20: 2441–2447.[Abstract/Free Full Text]
    
27. Jordan-Starck TC, Witte DP, Aronow BJ, et al. Apolipoprotein J: a membrane policeman? Curr Opin Lipidol. 1992; 3: 75–85.[CrossRef]
    
28. Bainton D, Miller NE, Bolton CH, et al. Plasma triglyceride and high density lipoprotein cholesterol as predictors of ischaemic heart disease in British men: the Caerphilly and Speedwell Collaborative Heart Disease Studies. Br Heart J. 1992; 68: 60–66.
    
29. Rose GA. The diagnosis of ischaemic heart pain and intermittent claudication in field surveys. Bull World Health Org. 1962; 27: 645–658.[Medline] [Order article via Infotrieve]
    
30. Blatter Garin M-C, Abbott C, Messmer S, et al. Quantification of human serum paraoxonase by enzyme-linked immunoassay: population differences in protein concentrations. Biochem J. 1994; 304: 549–554.
    
31. Sweetnam PM, Bolton CH, Downs LG, et al. Apolipoprotein A-I, A-II, and B, lipoprotein (a), and the risk of ischaemic heart disease: the Caerphilly Study. Eur J Clin Invest. 2000; 30: 947–956.[CrossRef][Medline] [Order article via Infotrieve]
    
32. Wilson PWF, D’Agostino RB, Levy D, et al. Prediction of coronary heart disease using risk factor categories. Circulation. 1998; 97: 1837–1847.[Medline] [Order article via Infotrieve]
    
33. Dietary supplementation with n-3 polyunsaturated fatty acids and vitamin E after myocardial infarction: results of the GISSI-Prevenzione trial. Gruppo Italiano per lo Studio della Sopravvivenza nell’Infarto miocardico. Lancet. 1999; 354: 447–455.[CrossRef][Medline] [Order article via Infotrieve]
    
34. Yusuf S, Degenais G, Pogue J, et al. Vitamin supplementation and cardiovascular events in high-risk patients: the Heart Outcomes Prevention Evaluation Study Investigators. N Engl J Med. 2000; 342: 154–160.[Abstract/Free Full Text]
    
35. Heart Protection Study Collaborative Group. MRC/BHF Heart Protection Study of antioxidant vitamin supplementation in 20,536 high-risk individuals: a randomised placebo-controlled trial. Lancet. 2002; 360: 23–33.[CrossRef][Medline] [Order article via Infotrieve]
    
36. Boaz M, Smetana S, Weinstein T, et al. Secondary prevention with antioxidants of cardiovascular disease in end-stage renal disease (SPACE): randomised placebo-controlled trial. Lancet. 2000; 356: 1213–1218.[CrossRef][Medline] [Order article via Infotrieve]
    
37. Durrington PN, Mackness B, Mackness MI. The hunt for nutritional and pharmacological modulators of paraoxonase. Arterioscler Thromb Vasc Biol. 2002; 22: 1248–1250.[Free Full Text]
    
38. Leviev I, Poirier O, Nicaud V, et al. High expressor paraoxonase PON1 gene promoter polymorphisms are associated with reduced risk of vascular disease in younger coronary patients. Atherosclerosis. 2002; 161: 463–467.[CrossRef][Medline] [Order article via Infotrieve]
    

This article has been cited by other articles:

				D J Hausenloy and D M Yellon Targeting residual cardiovascular risk: raising high-density lipoprotein cholesterol levels Heart, June 1, 2008; 94(6): 706 - 714. [Abstract] [Full Text] [PDF]

				M. V. Poulakou, K. I. Paraskevas, I. S. Vlachos, S.-A. P. Karabina, M. R. Wilson, D. C. Iliopoulos, S. I. Tsitsilonis, D. P. Mikhailidis, and D. N. Perrea Effect of Statins on Serum Apolipoprotein J and Paraoxonase-1 Levels in Patients With Ischemic Heart Disease Undergoing Coronary Angiography Angiology, May 1, 2008; 59(2): 137 - 144. [Abstract] [PDF]

				R. Movva and D. J. Rader Laboratory Assessment of HDL Heterogeneity and Function Clin. Chem., May 1, 2008; 54(5): 788 - 800. [Abstract] [Full Text] [PDF]

				P. W. Connelly, G. F. Maguire, C. M. Picardo, J. F. Teiber, and D. Draganov Development of an immunoblot assay with infrared fluorescence to quantify paraoxonase 1 in serum and plasma J. Lipid Res., January 1, 2008; 49(1): 245 - 250. [Abstract] [Full Text] [PDF]

				A. Sarandol, S. Kirli, C. Akkaya, N. Ocak, E. Eroz, and E. Sarandol Coronary artery disease risk factors in patients with schizophrenia: effects of short term antipsychotic treatment J Psychopharmacol, November 1, 2007; 21(8): 857 - 863. [Abstract] [PDF]

				L. Gaidukov and D. S. Tawfik The development of human sera tests for HDL-bound serum PON1 and its lipolactonase activity J. Lipid Res., July 1, 2007; 48(7): 1637 - 1646. [Abstract] [Full Text] [PDF]

				C. J. Ng, N. Bourquard, S. Y. Hama, D. Shih, V. R. Grijalva, M. Navab, A. M. Fogelman, and S. T. Reddy Adenovirus-Mediated Expression of Human Paraoxonase 3 Protects Against the Progression of Atherosclerosis in Apolipoprotein E-Deficient Mice Arterioscler. Thromb. Vasc. Biol., June 1, 2007; 27(6): 1368 - 1374. [Abstract] [Full Text] [PDF]

				R. S. Birjmohun, S. I. van Leuven, J. H.M. Levels, C. van 't Veer, J. A. Kuivenhoven, J. C.M. Meijers, M. Levi, J. J.P. Kastelein, T. van der Poll, and E. S.G. Stroes High-Density Lipoprotein Attenuates Inflammation and Coagulation Response on Endotoxin Challenge in Humans Arterioscler. Thromb. Vasc. Biol., May 1, 2007; 27(5): 1153 - 1158. [Abstract] [Full Text] [PDF]

				D. M. Shih, Y.-R. Xia, X.-P. Wang, S. S. Wang, N. Bourquard, A. M. Fogelman, A. J. Lusis, and S. T. Reddy Decreased Obesity and Atherosclerosis in Human Paraoxonase 3 Transgenic Mice Circ. Res., April 27, 2007; 100(8): 1200 - 1207. [Abstract] [Full Text] [PDF]

				L. Gaidukov, M. Rosenblat, M. Aviram, and D. S. Tawfik The 192R/Q polymorphs of serum paraoxonase PON1 differ in HDL binding, lipolactonase stimulation, and cholesterol efflux J. Lipid Res., November 1, 2006; 47(11): 2492 - 2502. [Abstract] [Full Text] [PDF]

				M. Mastorikou, M. Mackness, and B. Mackness Defective Metabolism of Oxidized Phospholipid by HDL From People With Type 2 Diabetes Diabetes, November 1, 2006; 55(11): 3099 - 3103. [Abstract] [Full Text] [PDF]

				C. J. Ng, N. Bourquard, V. Grijalva, S. Hama, D. M. Shih, M. Navab, A. M. Fogelman, A. J. Lusis, S. Young, and S. T. Reddy Paraoxonase-2 Deficiency Aggravates Atherosclerosis in Mice Despite Lower Apolipoprotein-B-containing Lipoproteins: ANTI-ATHEROGENIC ROLE FOR PARAOXONASE-2 J. Biol. Chem., October 6, 2006; 281(40): 29491 - 29500. [Abstract] [Full Text] [PDF]

				E. Thomas-Moya, M. Gianotti, A. M. Proenza, and I. Llado The age-related paraoxonase 1 response is altered by long-term caloric restriction in male and female rats J. Lipid Res., September 1, 2006; 47(9): 2042 - 2048. [Abstract] [Full Text] [PDF]

				A. Kontush and M. J. Chapman Functionally Defective High-Density Lipoprotein: A New Therapeutic Target at the Crossroads of Dyslipidemia, Inflammation, and Atherosclerosis Pharmacol. Rev., September 1, 2006; 58(3): 342 - 374. [Abstract] [Full Text] [PDF]

				B. Mackness, R. Quarck, W. Verreth, M. Mackness, and P. Holvoet Human Paraoxonase-1 Overexpression Inhibits Atherosclerosis in a Mouse Model of Metabolic Syndrome Arterioscler. Thromb. Vasc. Biol., July 1, 2006; 26(7): 1545 - 1550. [Abstract] [Full Text] [PDF]

				M. Graner, R. W. James, J. Kahri, M. S. Nieminen, M. Syvanne, and M.-R. Taskinen Association of Paraoxonase-1 Activity and Concentration With Angiographic Severity and Extent of Coronary Artery Disease J. Am. Coll. Cardiol., June 20, 2006; 47(12): 2429 - 2435. [Abstract] [Full Text] [PDF]

				A. H.E.M. Klerkx, K. E. Harchaoui, W. A. van der Steeg, S. M. Boekholdt, E. S.G. Stroes, J. J.P. Kastelein, and J. A. Kuivenhoven Cholesteryl Ester Transfer Protein (CETP) Inhibition Beyond Raising High-Density Lipoprotein Cholesterol Levels: Pathways by Which Modulation of CETP Activity May Alter Atherogenesis Arterioscler. Thromb. Vasc. Biol., April 1, 2006; 26(4): 706 - 715. [Abstract] [Full Text] [PDF]

				M. Rosenblat, L. Gaidukov, O. Khersonsky, J. Vaya, R. Oren, D. S. Tawfik, and M. Aviram The Catalytic Histidine Dyad of High Density Lipoprotein-associated Serum Paraoxonase-1 (PON1) Is Essential for PON1-mediated Inhibition of Low Density Lipoprotein Oxidation and Stimulation of Macrophage Cholesterol Efflux J. Biol. Chem., March 17, 2006; 281(11): 7657 - 7665. [Abstract] [Full Text] [PDF]

				M.-C. Blatter Garin, X. Moren, and R. W. James Paraoxonase-1 and serum concentrations of HDL-cholesterol and apoA-I J. Lipid Res., March 1, 2006; 47(3): 515 - 520. [Abstract] [Full Text] [PDF]

				V. Charlton-Menys, Y. Liu, and P. N. Durrington Semiautomated Method for Determination of Serum Paraoxonase Activity Using Paraoxon as Substrate Clin. Chem., March 1, 2006; 52(3): 453 - 457. [Abstract] [Full Text] [PDF]

				A. Gutierrez, E. P. Ratliff, A. M. Andres, X. Huang, W. L. McKeehan, and R. A. Davis Bile Acids Decrease Hepatic Paraoxonase 1 Expression and Plasma High-Density Lipoprotein Levels Via FXR-Mediated Signaling of FGFR4 Arterioscler. Thromb. Vasc. Biol., February 1, 2006; 26(2): 301 - 306. [Abstract] [Full Text] [PDF]

				P. M. Erlich, K. L. Lunetta, L. A. Cupples, M. Huyck, R. C. Green, C. T. Baldwin, L. A. Farrer, and for the MIRAGE Study Group Polymorphisms in the PON gene cluster are associated with Alzheimer disease Hum. Mol. Genet., January 1, 2006; 15(1): 77 - 85. [Abstract] [Full Text] [PDF]

				Prepared by: British Cardiac Society, British Hype JBS 2: Joint British Societies' guidelines on prevention of cardiovascular disease in clinical practice Heart, December 1, 2005; 91(suppl_5): v1 - v52. [Full Text] [PDF]

				L. S. Rozek, T. S. Hatsukami, R. J. Richter, J. Ranchalis, K. Nakayama, L. A. McKinstry, D. A. Gortner, E. Boyko, G. D. Schellenberg, C. E. Furlong, et al. The correlation of paraoxonase (PON1) activity with lipid and lipoprotein levels differs with vascular disease status J. Lipid Res., September 1, 2005; 46(9): 1888 - 1895. [Abstract] [Full Text] [PDF]

				A. Chait, C. Y. Han, J. F. Oram, and J. W. Heinecke Thematic review series: The Immune System and Atherogenesis. Lipoprotein-associated inflammatory proteins: markers or mediators of cardiovascular disease? J. Lipid Res., March 1, 2005; 46(3): 389 - 403. [Abstract] [Full Text] [PDF]

				S. D. Nguyen and D.-E. Sok Preferential inhibition of paraoxonase activity of human paraoxonase 1 by negatively charged lipids J. Lipid Res., December 1, 2004; 45(12): 2211 - 2220. [Abstract] [Full Text] [PDF]