Influence of smoking and smoking cessation on biomarkers of endothelial function and their association with mortality.

BACKGROUND AND AIMS: Endothelial dysfunction precedes atherosclerosis and smoking is a well-known risk factor for the development of endothelial dysfunction. The aim of our study was to analyse the effect of smoking on circulating markers of endothelial function and to investigate whether such effects have an influence on the potential use of these markers to estimate cardiovascular risk. METHODS: Stratified for smoking, levels of sE-/sP-/sL-selectin, von Willebrand (vWF), sICAM-1 and sVCAM-1, their association with mortality using Cox regression, and their accuracy of risk prediction using area-under-the-ROC-curve and net-reclassification-index were analysed in 1926 participants from the Ludwigshafen Risk and Cardiovascular Health (LURIC) - a prospective case-control study in patients who underwent coronary angiography with a median mortality follow-up of 10.6 years. RESULTS: In smokers, higher concentrations of sICAM-1, sE-selectin sP-selectin, but lower concentrations of sL-selectin and sVCAM-1, were detected compared to never-smokers. A direct association with mortality was found for levels of sICAM-1, sVCAM-1 and vWF regardless of smoking. Low sL-selectin levels were inversely associated with mortality in heavy and light smokers, with hazard ratios of 0.72 and 0.67 per 1-SD increase, adjusted for cardiovascular risk factors. Adding sL-selectin to a model based on traditional risk factors significantly improved AUC from 0.725 to 0.752 (p = 0.034) with an NRI of 43% (16.9%-62.3%). CONCLUSIONS: Smoking alters the concentration of circulating markers of endothelial function. sL-selectin is decreased in smokers, inversely associated with risk, and could be a useful marker to improve risk prediction.

Adiponectin and Mortality in Smokers and Non-Smokers of the Ludwigshafen Risk and Cardiovascular Health (LURIC) Study.

Cardiovascular diseases (CVD) are an important cause of morbidity and mortality worldwide. A decreased concentration of adiponectin has been reported in smokers. The aim of this study was to analyze the effect of cigarette smoking on the concentration of adiponectin and potassium in active smokers (AS) and life-time non-smokers (NS) of the Ludwigshafen Risk and Cardiovascular Health (LURIC) Study, and the use of these two markers for risk prediction. Smoking status was assessed by a questionnaire and measurement of plasma cotinine concentration. The serum concentration of adiponectin was measured by ELISA. Adiponectin was binned into tertiles separately for AS and NS and the Cox regression was used to assess the effect on mortality. There were 777 AS and 1178 NS among the LURIC patients. Within 10 years (median) of follow-up 221 AS and 302 NS died. In unadjusted analyses, AS had lower concentrations of adiponectin. However, after adjustment for age and gender there was no significant difference in adiponectin concentration between AS and NS. In the Cox regression model adjusted for age and gender, adiponectin was significantly associated with mortality in AS, but not in NS, with hazard ratio (95 % CI) of 1.60 (1.14-2.24) comparing the third with first tertile. In a model further adjusted for the risk factors, such as diabetes mellitus, hypertension, coronary artery disease, body mass index, LDL-cholesterol and HDL-cholesterol, adiponectin was significantly associated with mortality with hazard ratio of 1.83 (1.28-2.62) and 1.56 (1.15-2.11) for AS and NS, respectively. We conclude that increased adiponectin is a strong and independent predictor of mortality in both AS and NS. The determination of adiponectin concentration could be used to identify individuals at increased mortality risk.

The Renin-Angiotensin-Aldosterone System in Smokers and Non-Smokers of the Ludwigshafen Risk and Cardiovascular Health (LURIC) Study.

High concentrations of renin and aldosterone are risk factors for cardiovascular diseases (CVD) which are the leading cause of morbidity and mortality worldwide. Enhanced activation of the renin-angiotensin-aldosterone system (RAAS) by cigarette smoking has been reported. The aim of our study was to analyze the effect of cigarette smoking on parameters of the RAAS in active smokers (AS) and life-time non-smokers (NS) of the Ludwigshafen Risk and Cardiovascular Health (LURIC) Study as well as the utility of RAAS parameter for risk prediction. We determined the concentration of aldosterone, renin, angiotensin-I and angiotensin-II in participants of the LURIC study. Smoking status was assessed by a questionnaire and the measurement of plasma cotinine concentration. Parameters were log transformed before entering analyses, where appropriate. We used a multivariate Cox regression analysis to assess the effect of parameters on mortality. From the 3316 LURIC participants 777 were AS and 1178 NS. Within a median observation period of 10 years 221 (28.4 %) AS and 302 (25.6 %) NS died. After adjustment for age, gender, and the use of anti-hypertensive medication, only angiotensin-I was significantly different in AS compared to NS with an estimated marginal mean (95 % CI) of 1607 (1541-1673) ng/L and 1719 (1667-1772) ng/L, respectively. For both NS and AS renin and angiotensin-II were directly associated with mortality in the multivariate Cox regression analysis. Angiotensin-I was only associated with increased risk for mortality in NS (HR (95 % CI) of 0.69 (0.53-0.89)). We conclude that increased renin and angiotensin-II are independent predictors of mortality in AS and NS, while angiotensin-I was associated with reduced risk of death in NS only.

Product Failures in Respirators and Consumables: Analysis of Field Safety Notices of 2005-2013 Publicized by the Federal Institute for Drugs and Medical Devices in Germany.

The current European system governed by the three EC directives 93/42/EEC (Medical Device Directive), 98/79/EC (In-Vitro Diagnostic Directive) and 90/385/EEC (Active Implantable Medical Device Directive) regulates marketing and post-market surveillance of medical devices in the European Economic Area (EEA). In cases of incidents raising the field safety corrective actions (FSCA), manufacturers have to inform the responsible Competent Authority (CA; in Germany this is the Federal Institute for Drugs and Medical Devices, BfArM) and the public by field safety notices (FSN). In this study we analyzed FSN of respirators and consumables directly required for their function, whereas devices for anesthesia and gas delivery were excluded. FSCA and FSN of 2005-2013 publicized by BfArM for the included products were analyzed with respect to the MEDDEV 2.12-1 rev. 8. In total, 60 FSCA were publicized. German and English FSN were found in 59/53 cases, respectively. FSN were clearly characterized as FSN in 44/38 cases and declaration of the type of action in 45/44 cases, respectively. Product names were provided in all cases. Lot numbers or other information for product characterization were available in 7/7 and 43/40 cases, respectively. Detailed information regarding FSCA and product malfunction was found in all cases. Information on product related risks with previous use of affected devices was provided in 42/38 cases. In 53/53 cases manufacturers provided information to mitigate product related risks. Requests to pass FSN to persons needing awareness in the organization were found in 27/24 cases. Contact data were provided in 53/48 cases, respectively. Confirmation that a CA was informed was found in 28/26 cases and in 19/15 cases a customer confirmation was included. The identified risks were: total loss of function (19/16), short circuit (1/1) and burn (3/3), and inhalation of foreign particles (1/1) which might cause severe risk to patients and users. The most frequent FSCA were product modifications and customer information. The data suggest that there is an annually increasing number of FSCA on devices included in our study. Most FSN fulfill the criteria of MEDDEV 2.12-1 rev. 8. However, there are differences between German and English FSN, e.g., regarding the distribution to persons needing awareness, missing statement that a CA was informed, and missing customer confirmation. Due to the importance of FSN for reduction of product related risks in FSCA, the type and content of FSN should be further improved.

Field Safety Notes in Product Problems of Medical Devices for Use in Pulmonology.

The current European system for medical devices is governed by three EC directives: the Medical Device Directive 93/42/EEC, the In-Vitro Diagnostic Directive 98/79/EC and the Active Implantable Medical Device Directive 90/385/EEC and regulates marketing and post-market surveillance of medical devices in the European Economic Area. In cases of incidents and field safety corrective actions (FSCA) manufacturers have to inform the responsible Competent Authority, which is the Federal Institute for Drugs and Medical Devices (BfArM) and the public by field safety notices (FSN). In this study we analyzed FSN of medical devices exclusively serving for diagnostics or treatment in pulmonology (e.g. nebulizers, oxygen concentrators, pulse oximeters, lung function analyzers, and non-active devices for treatment). FSCA and FSN publicized by BfArM in 2005-2013 were analyzed in respect to the MEDDEV 2.12-1 rev 8. In total 41 FSCA were publicized for the included products. German and English FSN were found in 36/35 cases, respectively. FSN were clearly characterized as FSN in 22/20 cases and declaration of the type of action was found in 27/26 cases, respectively. Product names were provided in all cases. Lot numbers or other information for product characterization were available in 7/8 and 26/24 cases, respectively. Detailed information regarding FSCA and product malfunction were found in 27/33 and 36/35 cases, respectively. Information on product related risks with previous use of the affected product was provided in 24/23 cases. In 34/34 cases manufacturers provided information to mitigate product related risks. Requests to pass FSN to persons needing awareness were found in 10/14 cases. Contact data were provided in 30/30 cases. Confirmation that the Competent Authority was informed was found in 12/14 cases and in 19/18 cases a customer confirmation was included. The obtained data suggest that there is an increasing annual number of FSCA and most FSN fulfill the criteria of MEDDEV 2.12-1 rev 8. However, there are differences between German and English FSN, e.g. regarding the distribution to persons needing awareness, missing statement that the Competent Authority was informed and missing customer confirmation. Due to the importance of FSN for reduction of product related risks in FSCA type and content of FSN should be further improved.

Plasma Fibrinolysis Parameters in Smokers and Non-smokers of the Ludwigshafen Risk and Cardiovascular Health (LURIC) Study.

Cardiovascular diseases (CVD) are an important cause of morbidity and mortality worldwide. Parameters of coagulation and fibrinolysis are risk factors of CVD and might be affected by cigarette smoking. Aim of our study was to analyze the effect of cigarette smoking on parameters of fibrinolysis in active smokers (AS) and life-time non-smokers (NS) of the Ludwigshafen Risk and Cardiovascular Health (LURIC) Study as well as the use of these parameters for risk prediction. We determined plasminogen activator inhibitor-1 (PAI-1), tissue plasminogen activator antigen (t-PA), protein C activity, and D-dimers in 3,316 LURIC patients. Smoking status was assessed by a questionnaire and measurement of plasma cotinine concentration. Cox regression was used to assess the effect of parameters on mortality. We found that of the 3,316 LURIC patients 777 were AS and 1,178 NS. Within the observation period of 10 years (median) 221 AS and 302 NS died. In male AS vs. NS, PAI-1 (19.0 (10.0-35.0) vs. 15.0 (9.0-29.0) U/ml; p=0.026) and t-PA antigen (12.7 (9.6-16.3) vs. 11.6 (8.9-14.6) µg/l; p=0.020) were slightly increased, while t-PA activity was slightly decreased (0.63 (0.30-1.05) vs. 0.68 (0.42-1.10) U/l; p=0.005). In female AS vs. NS, t-PA antigen (10.5 (8.3-13.9) vs. 11.5 (8.8-15.0) µg/l; p=0.025) and protein C (108.0±24.1% vs. 118.0±25.7%; p=0.004) were decreased. All parameters except for protein C were predictive for mortality in AS. Fully adjusted hazard ratios (95% CI) were 1.14 (1.04-1.25), 1.19 (1.06-1.34), and 1.29 (1.11-1.49) per 1SD increase for D-dimer, t-PA, and PAI-1, respectively. Including fibrinolysis parameters in risk prediction models for mortality improved the area-under-the-curve (AUC) significantly compared with the conventional risk factors. In conclusion, we found alterations in the fibrinolytic system in smokers, which were more pronounced in male AS. PAI-1, t-PA and D-dimers were significant predictors of mortality in AS in LURIC and should be included into the assessment of cardiovascular risk particularly in patients at risk.

Cotinine as a marker for risk prediction in the Ludwigshafen Risk and Cardiovascular Health Study.

BACKGROUND: Cotinine is one of the major metabolites of nicotine. The aim our study was to investigate cotinine as a marker for individual risk prediction in the Ludwigshafen Risk and Cardiovascular Health study. METHODS: 840 samples had detectable cotinine measured using a radioimmunoassay (RIA nicotine metabolite, DPC Biermann GmbH). The distribution of risk factors across quartiles of cotinine or pack-years was analyzed by ANOVA and the association of cotinine and pack-years with mortality by Cox regression. RESULTS: Cotinine and pack-years both showed significant association with mortality in adjusted models with HRs (95% CI) of 1.30 (1.17-1.44) and 1.26 (1.13-1.42) comparing the third to the first tertile for cotinine and pack-years, respectively. Either cotinine or pack-years or self-reported smoking increased the area-under-the-curve significantly as compared to a basic model including other risk factors. DISCUSSION: Cotinine is a strong predictor of mortality in non-smokers as well as in smokers. As objectively measurable parameter cotinine would be preferable for risk prediction.

Aerosolized GLP-1 for treatment of diabetes mellitus and irritable bowel syndrome.

Diabetes is a global burden and the prevalence of the disease, in particular diabetes mellitus type 2 is rapidly increasing worldwide. After introduction of insulin into clinical therapy about 90 years ago a major number of pharmaceuticals has been developed for treatment of diabetes mellitus type 2. One of these, the incretin glucagon-like peptide 1 (GLP-1), like insulin, needs subcutaneous administration causing inconvenience to patients. However, administration of GLP-1 plays also a role for treatment of irritable bowel syndrome (IBS). To improve patient convenience inhaled insulin (Exubera(®)) was developed and approved but failed market acceptance some years ago. Recently, another inhalative insulin (Afrezza(®)) received market approval and GLP-1 may serve as another candidate drug for inhalative administration. This review analyzes the current literature investigating alternative administration of GLP-1 and GLP-1 analogs focusing on inhalation. Several formulations for inhalative administration of GLP-1 and analogs were investigated in animal studies, whereas there are only few clinical data. However, feasibility of GLP-1 inhalation has been shown and should be further investigated as such type of drug administration may serve for improvement of therapy in patients with diabetes mellitus or irritable bowel syndrome.

Does customer information fulfill MEDDEV criteria in cases of product problems of in vitro diagnostics for infection testing?

The European Directive 98/79/EC on in vitro diagnostics (IVD) regulates marketing and post market surveillance of IVD in the European Economic Area. In cases of incidents and field safety corrective actions (FSCA) manufacturers have to inform responsible competent authority (CA) and public by field safety notices (FSN). We analyzed FSCA and FSN of IVD for infection testing (culture media, reagents, kits, control materials, as well as culture-based analyzers and their general consumables) published by the Federal Institute for Drugs and Medical Devices (BfArM) in Bonn, Germany in 2005-2012 in regard to the European Regulatory Framework of Medical Devices (MEDDEV). One hundred and sixty-nine FSCA were published and German and English FSN were found in 157 and 154 cases, respectively. FSN were clearly characterized as FSN in 110 German and 134 English cases and product names were provided in 157 and 154 cases, respectively. Lot numbers and other information for product characterization were available in 146 and 137 cases, respectively. The information regarding FSCA and product malfunction was provided in 157 and 151 and 144 and 136 cases and that regarding the product related risks with continued use of affected IVD in 116 and 116 cases, respectively. In 156 German and 152 English cases, manufacturers provided the information for risk mitigation, including retesting in 69 and 75 cases, respectively. Requests to pass FSN to persons needing awareness were found in 108 and 87 cases, and contact data were provided in 127 and 131 cases, respectively. We conclude that most FSN fulfilled the MEDDEV criteria. However, type and content of FSN should be improved to ensure a better mitigation of risks due to product failure.

Low-density lipoprotein particle diameter and mortality: the Ludwigshafen Risk and Cardiovascular Health Study.

AIMS: The aim of the study was to examine whether differences in average diameter of low-density lipoprotein (LDL) particles were associated with total and cardiovascular mortality. METHODS AND RESULTS: We studied 1643 subjects referred to coronary angiography, who did not receive lipid-lowering drugs. During a median follow-up of 9.9 years, 398 patients died, of these 246 from cardiovascular causes. We calculated average particle diameters of LDL from the composition of LDL obtained by ß-quantification. When LDL with intermediate average diameters (16.5-16.8 nm) were used as reference category, the hazard ratios (HRs) adjusted for cardiovascular risk factors for death from any cause were 1.71 (95% CI: 1.31-2.25) and 1.24 (95% CI: 0.95-1.63) in patients with large (>16.8 nm) or small LDL (<16.5 nm), respectively. Adjusted HRs for death from cardiovascular causes were 1.89 (95% CI: 1.32-2.70) and 1.54 (95% CI: 1.06-2.12) in patients with large or small LDL, respectively. Patients with large LDL had higher concentrations of the inflammatory markers interleukin (IL)-6 and C-reactive protein than patients with small or intermediate LDL. Equilibrium density gradient ultracentrifugation revealed characteristic and distinct profiles of LDL particles in persons with large (approximately even distribution of intermediate-density lipoproteins and LDL-1 through LDL-6) intermediate (peak concentration at LDL-4) or small (peak concentration at LDL-6) average LDL particle diameters. CONCLUSIONS: Calculated LDL particle diameters identify patients with different profiles of LDL subfractions. Both large and small LDL diameters are independently associated with increased risk mortality of all causes and, more so, due to cardiovascular causes compared with LDL of intermediate size.

Fractional exhaled nitric oxide in clinical trials: an overview.

Designing clinical trials in asthma it is crucial to find the perfect primary endpoint for showing bioequivalence, especially when the investigational medicinal product is not a bronchodilator, but a substance, which suppresses the inflammatory process, e.g. inhalative corticosteroids (ICS). In the past, lung function parameters were used as the primary endpoint, which entails a long study duration and hundreds of patients. The measurement of fractional exhaled nitric oxide (FeNO) is established as a non-invasive marker for eosinophilic inflammation, and several guidelines focus on that diagnosis. FeNO is a surrogate measure of eosinophilic inflammation and at the same time, eosinophilic airway inflammation is usually steroid responsive. Thus, FeNO should be a part of the clinical management of asthma in ambulatory settings in conjunction with other conventional methods of asthma assessment. Furthermore, FeNO should be used to determine the presence or absence of eosinophilic airway inflammation, to determine the likelihood of steroid responsiveness, to measure response to steroid therapy, and level of inflammation control. In addition, FeNO is a useful tool to monitor patient ICS treatment adherence and allergen exposure. FeNO may be used to predict steroid responsiveness and as a measure to determine the optimal treatment of airway inflammation. FeNO has all characteristics of a good marker for bioequivalence measurements in the market approval process of generic ICS products. With a reliable study design in terms of patient population, concomitant medication, equipment and other factors, which can influence the measurement, efficient clinical trials can be performed, with a relatively short treatment time of 2-4 weeks and 50-100 patients.

Smoking, apolipoprotein E genotypes, and mortality (the Ludwigshafen RIsk and Cardiovascular Health study).

AIMS: The genetic polymorphism of apolipoprotein E (APOE) has been suggested to modify the effect of smoking on the development of coronary artery disease (CAD) in apparently healthy persons. The interaction of these factors in persons undergoing coronary angiography is not known. METHODS AND RESULTS: We analysed the association between the APOE-genotype, smoking, angiographic CAD, and mortality in 3263 participants of the LUdwigshafen RIsk and Cardiovascular Health study. APOE-genotypes were associated with CAD [ε22 or ε23: odds ratio (OR) 0.56, 95% confidence interval (CI) 0.43-0.71; ε24 or ε34 or ε44: OR 1.10, 95% CI 0.89-1.37 compared with ε33] and moderately with cardiovascular mortality [ε22 or ε23: hazard ratio (HR) 0.71, 95% CI 0.51-0.99; ε33: HR 0.92, 95% CI 0.75-1.14 compared with ε24 or ε34 or ε44]. HRs for total mortality were 1.39 (95% CI 0.39-0.1.67), 2.29 (95% CI 1.85-2.83), 2.07 (95% CI 1.64-2.62), and 2.95 (95% CI 2.10-4.17) in ex-smokers, current smokers, current smokers without, or current smokers with one ε4 allele, respectively, compared with never-smokers. Carrying ε4 increased mortality in current, but not in ex-smokers (HR 1.66, 95% CI 1.04-2.64 for interaction). These findings applied to cardiovascular mortality, were robust against adjustment for cardiovascular risk factors, and consistent across subgroups. No interaction of smoking and ε4 was seen regarding non-cardiovascular mortality. Smokers with ε4 had reduced average low-density lipoprotein (LDL) diameters, elevated oxidized LDL, and lipoprotein-associated phospholipase A2. CONCLUSION: In persons undergoing coronary angiography, there is a significant interaction between APOE-genotype and smoking. The presence of the ε4 allele in current smokers increases cardiovascular and all-cause mortality.

Costs of smoking-attributable productivity losses in Poland.

In Poland smoking poses a severe socioeconomic problem. Not only does tobacco consumption cause an increase in direct medical costs due to the necessity for treatment of smoking-attributable diseases, but it also generates indirect costs due to productivity losses. The aim of this paper was to estimate the annual productivity loss due to smoking in Poland from the societal perspective and to compare the obtained results with the equivalent research in other selected countries (Germany, Sweden, and USA). The assessment was performed by the use of the human capital approach, considering loss of productivity until achieving the retirement age and gross income. Four distinct components of indirect costs of nicotine consumption were included: costs of premature mortality, costs of acquired disability, as well as costs of absenteeism and presenteeism caused by smokers. The costs of smoking-attributable productivity loss within a year amount to more than 15 billion PLN (1 Euro approx. 4 PLN) which is about 402 PLN per capita and 1418 PLN per smoker. This represents about 2.6% of Polish annual Gross Domestic Product (GDP), which is more than in Germany, Sweden, or the USA. This amount clearly shows the enormous socioeconomic burden and suggests the need for taking measures to reduce it.

Roles of oxidants, nitric oxide, and asymmetric dimethylarginine in endothelial function.

Vascular endothelium plays a crucial role in ensuring normal function and morphology of blood vessels, and many risk factors of atherosclerosis act via their effects on endothelial cells. However, endothelial dysfunction is induced by very different pathomechanisms. In principle, it is caused by an impaired bioavailability of nitric oxide (NO) due to an inhibited synthesis (eg, by asymmetric dimethylarginine [ADMA]) or increased consumption of formed NO (by reactive oxygen species [ROS]). ROS can be synthesized in the organism (eg, by different enzymes) or can be administered from the environment (eg, by cigarette smoking), whereas ADMA is the subject of endogenous metabolism only. Many studies have elucidated the system of pathomechanisms and targeted some as potential goals for therapeutic interventions. This review demonstrates roles of ROS, NO, ADMA, endothelin, and estrogen in endothelial function and dysfunction focusing on homocysteinemia and diabetes mellitus and provide examples for the medical treatment of endothelial dysfunction.

Experience with post-market surveillance of in-vitro diagnostic medical devices for lay use in Germany.

BACKGROUND: The European Directive 98/79/EC on in-vitro diagnostic medical devices (IVDs) regulates IVD marketing practices and post-market surveillance. IVD manufacturers have to inform the responsible Competent Authorities of any issues. In Germany, the Federal Institute for Drugs and Medical Devices (BfArM) is responsible for most IVDs, with a small subset of IVDs being within the responsibility of the Paul-Ehrlich-Institute (PEI). METHODS: All IVD notifications received by BfArM between 1999 and June 2006 were analysed in terms of the source of notification, underlying product defects and corrective actions. RESULTS: A total of 773 notifications were received, 566 related to IVDs for professional use and 207 related to over-the-counter (OTC) products for lay use. The latter included systems for blood glucose testing (analysers, tests and control materials; n=166) or coagulation testing (n=13) and pregnancy tests (n=25). Most reports came from manufacturers (n=115; 55.6%) and users (n=72; 34.8%) mainly via pharmacies and the Drug Commission of the German Pharmaceutical Association. Manufacturer investigations for all lay IVD cases reported revealed underlying product defects in 53 cases (25.6%). Product failure was excluded in 80 cases (38.6%), which included a large number of user errors (n=34). Many cases (n=74, 35.7%) could not be clarified because the test strips and/or analysers were not returned to the manufacturer for further investigation. In most cases, product defects identified by manufacturer investigations were related to the test strips and not to the analysers. Because of the high proportion of cases without proven product failure, corrective actions were performed only in a subset (n=54, 26.1%) of the cases reported for IVDs specified for lay use. CONCLUSIONS: The results show that the governmental system for post-marketing surveillance of IVDs is an established tool to ensure product safety. The proportion of notifications for OTC products indicates that they should be the focus for action by the competent surveillance authorities.

Role of oxidants and antioxidants in atherosclerosis: results of in vitro and in vivo investigations.

Both in vitro and in vivo studies have shown that oxidants are central in the development of atherosclerosis. Consequently, additional studies evaluated the protective effects of various natural and synthetic antioxidants, alone and in combination, with most studies focusing on alpha-tocopherol (vitamin E). Here, we summarize the role of oxidants in the pathomechanism of atherosclerosis. We also discuss epidemiological studies and others focused on the protective effect of vitamin E against atherosclerosis. Other antioxidants are also considered if they were included in studies involving vitamin E. The protective effect of antioxidants on atherosclerotic pathomechanisms has been confirmed in vitro, but only in some animal studies. Various epidemiological and observational studies have produced conflicting results on the protective effect of antioxidants. Most studies of primary or secondary prevention failed to show a protective effect. These conflicting results are biased by a number of factors, including differences between the study groups. Therefore, we describe these studies in detail.

Distribution spectrum of paraoxonase activity in HDL fractions.

BACKGROUND: Paraoxonase (PON1) associated with HDL can be regarded as a cardio- and vasoprotective enzyme. However, because HDL is not a homogeneous fraction, it is important to investigate in which subgroups of HDL active PON1 is located. It would also be useful to determine density profiles of the HDL apolipoproteins (Apo) E and J. METHODS: We investigated the density range of HDL (rho = 1.063-1.256 kg/L) in healthy individuals, using the ultracentrifugation reference method and a newly introduced automated fractionation method. Profiles of PON1 activity and ApoA-I, ApoA-II, ApoE, ApoJ, and cholesterol concentrations were obtained by use of various density gradients. RESULTS: PON1 activity was highest in the more dense HDL(3) and VHDL fractions where PON1 was not dissociated from the particles during centrifugation. The fraction in density range 1.175-1.185 kg/L showed not only the highest PON1 activity, but also the highest specific activity (activity per HDL particle). This fraction was the least-dense fraction containing both ApoE and ApoJ. Only the Q192R polymorphism had an effect on the distribution profile of PON1 activity. In contrast, L55M and the T(-107)C polymorphisms (determined by a novel nonradioactive method) were without effect on the density distribution of PON1 activity. CONCLUSION: The HDL(3) fraction, which is important in reverse cholesterol transport, also carries the highest PON1 activity.