Follistatin-like 1 (FSTL1) levels as potential early biomarker of cardiovascular disease in a Mexican population.

Cardiovascular diseases (CVD) are the leading cause of death globally. In recent years, follistatin-like protein 1 (FSTL1) has been proposed as an emerging potential clinical biomarker of CVD, since its concentration is upregulated in heart failure. The aim of the present study was to evaluate the association of FSTL1 levels and classic biomarkers with the risk of CVD in Mexican population. A case-control study was carried out in patients with cardiovascular diseases (CVD), arterial hypertension, but not CVD (cardiovascular risk factor-CRF), and healthy controls (control group) from the Mexican Institute of Social Security. Lipid profile, homocysteine (Hcys), serum amyloid A (SAA), FSTL1 concentration, PON1 concentration and activities [Arylesterase (ARE), and Lactonase (LAC)] were evaluated. High levels of FSTL1 were found in the CRF group and a positive association of FSTL1 (OR = 4.55; 95% CI 1.29-16.04, p = 0.02) with the presence of arterial hypertension, as well as Hcys (OR, 3.09; 95% CI 1.23-7.76, p = 0.02) and SAA (OR, 1.03; 95% CI 1.01-1.05, p < 0.01) with the presence of CVD. LAC activity (OR, 0.26; 95% CI 0.07-0.94, p = 0.04) and PON1 concentration (OR, 0.17; 95% CI 0.05-0.62, p = 0.01) were associated with a decrease in OR belonging to the group with CVD. Our results suggest that FSTL1 may be a useful biomarker for monitoring cardiovascular risk in clinical settings. However, longitudinal studies are needed to evaluate how FSTL1 could influence the association of PON1 activity and Hcys with CVD.

Improved risk assessment of coronary artery disease by substituting paraoxonase 1 activity for HDL-C: Novel cardiometabolic biomarkers based on HDL functionality.

BACKGROUND AND AIMS: Developing laboratory assays to evaluate HDL functions and improve cardiovascular disease (CVD) risk assessment has recently emerged as a challenge. The present study was conducted to help predict the risk of coronary artery disease (CAD) by investigating new cardiometabolic risk factors based on substituting paraoxonase 1 (PON1) as a critical enzyme in the functionality of HDL for that of HDL-C. METHODS AND RESULTS: The present study recruited 274 subjects undergoing diagnostic coronary angiography, 92 without significant CAD (non-CAD), and 182 with a severe CAD. The diagnostic accuracy of the new biomarkers in non-CAD versus multi-vessel disease was obtained in descending order of AUC as 0.72 (P < 0.001) for log (TG/PON1), 0.70 (P < 0.001) for nonHDL-C/PON1, and 0.67 (P < 0.001) for LDL-C/PON1. After performing a multivariate adjustment for age, gender, BMI, statin therapy, and diabetes mellitus, the increased odds of CAD remained significant for the new cardiometabolic ratios as independent variables [adjusted OR = 1.47 (1.15-1.88), p = 0.002 for LDL-C/PON1; adjusted OR = 2.15 (1.41-3.5), p = 0.009 for nonHDL-C/PON1; adjusted OR = 5.03 (2.14-13.02), p = 0.004 for log (TG/PON1)]. CAD was diagnosed with an optimal discriminating cutoff of 1.84 for LDL-C/PON1, 2.8 for nonHDL-C/PON1, and 0.48 for log (TG/PON1). CONCLUSIONS: To improve CAD's risk assessment, the PON1 activity was proposed as an alternative to HDL-C in the commonly used atherogenic lipid ratios. Substituting the PON1 activity for the HDL-C concentration can provide an index of the HDL activity. The present study sought to exploit the lipoprotein-related risk factors of CAD from a more effective perspective.

Phenotypes and concentration of PON1 in cardiovascular disease: The role of nutrient intake.

BACKGROUND AND AIMS: Paraoxonase 1 (PON1) is considered to play a crucial role as an anti-atherosclerotic factor. The PON1 activity is affected by genetic polymorphisms, environmental factors, age, sex, lifestyle, pharmaceutical drugs, and dietary factors. The aim of this study was to evaluate the association between macro- and micronutrients as well as PON1 concentration and activities in patients with cardiovascular diseases (CVD), cardiovascular risk factors but no CVD (CRF), and in healthy controls (control group). METHODS AND RESULTS: A case-control study was carried out with 356 volunteers from the Mexican Institute of Social Security, Mexico. Clinical parameters, lipid profile, PON1 activities (AREase, LACase, CMPAase and PONase), and PON1 concentration were evaluated. There was a differential intake of macro- and micronutrients among the study groups. The intake of proteins and carbohydrates was higher in the CVD group than in the CFR and control groups (p < 0.05). AREase, LACase, and CMPAase activities and PON1 concentration were lowest in the CVD group. CONCLUSION: LACase and CMPAase activities, as well as PON1 concentration, could be included in the battery of CVD predictive biomarkers in the Mexican population.

Assessment of PON1 activity and circulating TF levels in relation to BMI, testosterone, HOMA-IR, HDL-C, LDL-C, CHO, SOD activity and TAC in women with PCOS: An observational study.

BACKGROUND: Polycystic Ovary Syndrome (PCOS) is the most common female endocrinopathy among premenopausal women associated with hyperandrogenism, obesity, dyslipidemia, insulin resistance and inflammation. Oxidative stress is an important component of cardio-metabolic risk seen in PCOS. MATERIAL AND METHODS: A total of 95 women with PCOS and 95 healthy controls were included in this observational study. Serum PON1 activity and stress markers were measured by spectrophotometric methods. Circulating TF level was measured by ELISA. RESULTS: We found decreased PON1 activity and increased TF levels in women with PCOS compared to healthy controls. Fasting insulin, HOMA-IR, testosterone, LDL-C, MDA, PC and SOD activity were significantly increased whereas FGIR, QUICKI, HDLC, CAT and TAC were significantly decreased in PCOS women than controls. We observed a positive association of PON1 activity with FGIR, QUICKI, HDL-C and TAC, and its negative association was observed with LH, testosterone, fasting insulin and HOMA-IR in PCOS women. We further observed a positive association of TF with waist, waist to hip ratio, BMI, glucose 1hr, cholesterol, LDL-C, SGPT, uric acid and SOD activity in PCOS women. CONCLUSIONS: Decreased PON1 activity and raised circulating TF levels are respective indicators of pro-inflammatory and procoagulant status in PCOS women. The imbalanced oxidant/antioxidant status further supports the evidences that PCOS is an oxidant state. Further, the association of PON1 activity and TF levels with the clinical, laboratory findings and stress marker levels suggest that these factors taken together are involved in aggravating the pro-inflammatory status in PCOS women.

Assessment of the relationship between serum paraoxonase activity and epicardial adipose tissue in hemodialysis patients.

PURPOSE: Paraoxonase-1 (PON-1) is a high-density lipoprotein-associated (HDL) enzyme, which has been shown to reduce susceptibility to low-density lipoprotein (LDL) peroxidation. Epicardial adipose tissue (EAT) is a marker of atherosclerosis. The aim of this study was to determine the relationship between PON-1 activity and EAT in hemodialysis (HD) patients. METHODS: This is a cross-sectional study conducted on 72 (43 males) HD patients with end-stage renal disease. Serum levels for lipid profiles, C-reactive protein, calcium, phosphate, and parathyroid hormone were measured. PON-1 activity was also measured and compared to the rate of enzymatic hydrolysis of paraoxon to p-nitrophenol. Echocardiography was used to measure EAT thickness (EATT). The correlation between PON-1 and EATT was assessed, while independent predictors of EATT in HD patients were similarly assessed using multivariate regression analysis. RESULTS: There was a significant low mean value of PON-1 activity in HD patients compared with the control group (82.1 ± 31.6 vs. 164.3 ± 61.5 U/l, p = 0.0001) and significant high mean value of EATT in HD patients, compared with controls (6.2 ± 1.7 vs. 3.9 ± 1.1 mm, p = 0.0001). In addition, there was a significant negative correlation between PON-1 activity and EATT (r = -0.484, p = 0.0001) and a significant positive correlation between PON-1 activity and HDL-C (r = 0.417, p = 0.0003). PON-1, total cholesterol, triglycerides, LDL, HDL, age, and body mass index were found to be independent predictors of EATT. CONCLUSION: Our study demonstrated that PON-1 activity was significantly lower in HD patients compared with healthy controls and that PON-1 activity was inversely correlated with EATT in this population.

Serum paraoxonase 1 activity and lipid metabolism parameter changes in Dachshunds with chronic mitral valve disease. Assessment of its diagnostic usefulness.

Chronic mitral valve disease, which is frequently diagnosed in Dachshunds, leads to structural, hemodynamic and redox state changes in dogs. The aim of this study was to investigate serum paraoxonase 1 (PON1) activity and lipid metabolism in different disease stages. Standardized PON1 activity (PON1/HDL ratio) was lower in asymptomatic dogs, B1 and B2 Stages when compared to healthy ones and symptomatic Dachshunds in Stage C (ACVIM classfication). PON1 paraoxonase activity was elevated in Stage C dogs, with no changes found in PON1 activity towards phenyl acetate. Dachshunds in Stage B2 and C showed increased triglyceride levels, with no changes in cholesterol and lipoprotein concentration in comparison to healthy ones. Our data suggest that standardized PON1 activity changes could be used in laboratory diagnostics to differentiate the CMVD of affected asymptomatic (Stage B1 and B2) dogs from healthy (Stage A) and clinically affected (Stage C) dogs. Also, a standardized PON1 activity increase might be a prognostic progression signal of the disease to Stage C.

Onion extract (Allium cepa L.), quercetin and catechin up-regulate paraoxonase 1 activity with concomitant protection against low-density lipoprotein oxidation in male Wistar rats subjected to oxidative stress.

BACKGROUND: Paraoxonase 1 (PON1) protects the oxidative modification of low-density lipoprotein (LDL) and is a major anti-atherosclerotic protein component of high-density lipoprotein. We explored the effect of onion extract and flavonoids (quercetin and catechin) in the regulation of PON1 expression and correlating with oxidised LDL levels in male Wistar rats subjected to mercuric chloride (HgCl2) induced oxidative insult. Rats were divided into eight groups: Control, Experimental (HgCl2), Experimental + onion/catechin/quercetin, Positive control (Normal + onion/catechin/quercetin). Treatment continued for 4 weeks. RESULTS: PON1 activity and radical scavenging activity decreased in the Experimental group (P < 0.001) with increased susceptibility of LDL for oxidation and plasma malondialdehyde levels (P < 0.001). Onion extract significantly attenuated the adverse effects of HgCl2 by up-regulating PON1 activity (P < 0.05), radical scavenging activity (P < 0.01), and protected against LDL oxidation (P < 0.001) and lipid peroxidation (P < 0.01). Similar effects were observed with quercetin and to a lesser extent with catechin. CONCLUSIONS: The findings may explain the anti-atherosclerotic effect of onion and also foods containing quercetin and catechins.

Assessment of small C-fiber status for screening of oxidative stress in patients at risk of diabetes.

Oxidized LDL (oxLDL), anti-oxLDL antibody (anti-oxLDL) and paraoxonase (PON1) are increasingly being reported to be associated with diabetic atherosclerosis. Oxidative stress could affect also small C-fibers innervating the sweat glands even in prediabetes. Hence it could be hypothesized that sweat dysfunction may be a predictor of oxidative stress status for early detection of diabetes. Ezscan, a new device, has recently been developed to measure the sweat function. Therefore, this study was aimed to determine the relevance of this Ezscan method to identify impairment in oxidative stress parameters. Plasma levels of oxLDL and anti-oxLDL were measured by enzyme immunoassay and ELISA respectively. Small C-fiber status was assessed by measurement of hand and foot sweat function with the help of Ezscan device and subsequent calculation of a risk score. Out of 82 subjects recruited in this study, 38 had impaired glucose tolerance and 6 had newly diagnosed diabetes mellitus. Ezscan risk score was significantly (p=0.004) correlated with oxLDL/anti-oxLDL ratio (0.32). Area under the curve (AUC) of receiver operating characteristics (ROC) analysis for detection of oxLDL/anti-oxLDL ratio (>0.12) was 0.76. For an Ezscan risk score of 50%, the sensitivity and specificity were 68% and 71% respectively. After adjustment for age and BMI, PON1 activity showed significant difference among the 3 risk groups defined by Ezscan risk score. Based on these results it may be concluded that Ezscan could be a useful screening tool in daily practice to assess alterations in oxidative stress parameters in individuals at risk of developing diabetes.

Assessment of early atherosclerotic findings in patients with nasal polyposis.

OBJECTIVE: To investigate early markers of atherosclerosis in patients with nasal polyposis (NP) through measurements of carotid artery intima-media thickness (CIMT), flow-mediated vasodilatation (FMD) of the brachial artery and serum paraoxonase-1 (PON-1) activity. METHODS: Forty-five patients with NP were included in the study group and 45 healthy individuals in the control group. The diagnosis of patients with NP was predicated on anterior rhinoscopy, endoscopic nasal examination and coronal paranasal sinus computed tomography (CT). Measurements of CIMT and FMD of the brachial artery were performed by high-resolution ultrasonography. Serum PON-1 activity was evaluated by measuring the rate of paraoxon hydrolysis. RESULTS: Mean CIMT values were found to be increased in the NP group compared to the control group. However, mean FMD % values and serum PON-1 activity were significantly lower in the NP group compared to the control group. Moreover; the endoscopic polyps' scores and paranasal sinus CT scores were positively correlated with CIMT and negatively correlated with FMD % values and PON-1 activity. Disease duration also was positively correlated with CIMT and negatively correlated with FMD % values. CONCLUSION: Impaired FMD, increased CIMT and decreased serum PON-1 activity may be considered to be risk factors for accelerated atherosclerosis in patients with NP who may have subclinical atherosclerosis and be at risk for cardiovascular events in the future.

Assessment of the serum paraoxonase activity and oxidant/antioxidant status in patients with recurrent aphthous stomatitis.

OBJECTIVES: Several studies have indicated that recurrent aphthous stomatitis (RAS) is associated with oxidative stress. The aim of this study was to investigate serum paraoxonase (PON) activity and oxidant/antioxidant status in patients with RAS. DESIGN AND METHODS: Thirty-one patients with RAS and 31 healthy controls were enrolled. Serum PON1 and arylesterase activities, total antioxidant capacity, total oxidant status, and oxidative stress index were determined. RESULTS: Serum total antioxidant capacity levels, PON1, and arylesterase activities were significantly lower in RAS than controls (P < 0.001), while total oxidant status levels and oxidative stress index were significantly higher (P < 0.001). PON1 activity had a significant correlation with high-density lipoprotein cholesterol only (r = 0.482, P < 0.05), while there were no correlations with other lipids (P > 0.05) in patients with RAS. CONCLUSIONS: Our results indicate that RAS is associated with decreased PON1 activity and increased oxidative stress that plays a crucial role in the pathogenesis of RAS. Further studies on a larger number of patients are needed to verify these results.

Assessment of emerging biomarkers of liver injury in human subjects.

Hepatotoxicity remains a major challenge in drug development. Although alanine aminotransferase (ALT) remains the gold standard biomarker of liver injury, alternative biomarker strategies to better predict the potential for severe drug-induced liver injury (DILI) are essential. In this study, we evaluated the utility of glutamate dehydrogenase (GLDH), purine nucleoside phosphorylase (PNP), malate dehydrogenase (MDH), and paraxonase 1 (PON1) as indicators of liver injury in cohorts of human subjects, including healthy subjects across age and gender, subjects with a variety of liver impairments, and several cases of acetaminophen poisoning. In the healthy subjects, levels of GLDH and MDH were not affected by age or gender. Reference ranges for GLDH and MDH in healthy subjects were 1-10 and 79-176U/L, respectively. In contrast, the levels of PON1 and PNP were not consistent across cohorts of healthy subjects. Furthermore, GLDH and MDH had a strong correlation with elevated ALT levels and possessed a high predictive power for liver injury, as determined by ROC analysis. In contrast, PON1 and PNP did not detect liver injury in our study. Finally, evaluation of patients with acetaminophen-induced liver injury provided evidence that both GLDH and MDH might have utility as biomarkers of DILI in humans. This study is the first to evaluate GLDH, MDH, PON1, and PNP in a large number of human subjects and, and it provides an impetus for prospective clinical studies to fully evaluate the diagnostic value of GLDH and MDH for detection of liver injury.

Neurobehavioral assessment of mice following repeated postnatal exposure to chlorpyrifos-oxon.

Chlorpyrifos (CPF), one of the most widely-used organophosphorus (OP) insecticides in agriculture, is degraded in the field to its oxon form, chlorpyrifos-oxon (CPO), which can represent a significant contaminant in exposures to adults and children. CPO is also responsible for the acetylcholinesterase (AChE) inhibition associated with CPF exposures; CPF is converted by liver CYP450 enzymes to CPO, which binds to and inhibits AChE and other serine active-site esterases, lipases and proteases. Young children represent a particularly susceptible population for exposure to CPF and CPO, in part because levels of the plasma enzyme, paraoxonase (PON1), which hydrolyzes CPO, are very low during early development. While a number of studies have demonstrated developmental neurotoxicity associated with CPF exposure, including effects at or below the threshold levels for AChE inhibition, it is unclear whether these effects were due directly to CPF or to its active metabolite, CPO. PON1 knockout (PON1-/-) mice, which lack PON1, represent a highly sensitive mouse model for toxicity associated with exposure to CPF or CPO. To examine the neurobehavioral consequences of CPO exposure during postnatal development, PON1-/- mice were exposed daily from PND 4 to PND 21 to CPO at 0.15, 0.18, or 0.25 mg/kg/d. A neurobehavioral test battery did not reveal significant effects of CPO on early reflex development, motor coordination, pre-pulse inhibition of startle, startle amplitude, open field behavior, or learning and memory in the contextual fear conditioning, Morris water maze, or water radial-arm maze tests. However, body weight gain and startle latency were significantly affected by exposure to 0.25 mg/kg/d CPO. Additionally, from PNDs 15-20 the mice exposed repeatedly to CPO at all three doses exhibited a dose-related transient hyperkinesis in the 20-min period following CPO administration, suggesting possible effects on catecholaminergic neurotransmission. Our previous study demonstrated wide-ranging effects of neonatal CPO exposure on gene expression in the brain and on brain AChE inhibition, and modulation of both of these effects by the PON1(Q192R) polymorphism. The current study indicates that the neurobehavioral consequences of these effects are more elusive, and suggests that alternative neurobehavioral tests might be warranted, such as tests of social interactions, age-dependent effects on learning and memory, or tests designed specifically to assess dopaminergic or noradrenergic function.

Quantitative assessment of the influence of paraoxonase 1 activity and coronary heart disease risk.

Human paraoxonase 1 (PON1) is a calcium-dependent high-density lipoprotein associated ester hydrolase that has attracted considerable attention as a candidate factor for coronary heart disease (CHD) based on its function as a key factor in lipoprotein catabolism pathways. This meta-analysis aimed to clarify the inconsistency of published studies and to establish a comprehensive picture of the relationship between PON1 activity and CHD susceptibility. A systematic search was performed from PubMed, Web of Science, EMBASE, and CNKI databases. Ratio of means (RoM) between case and control and 95% confidence intervals (CIs) were calculated using a random-effects model. The source of heterogeneity was explored by subgroup analysis and meta-regression. We identified 47 eligible studies including a total of 9853 CHD cases and 11,408 controls. The pooled analysis showed that CHD patients had a 19% lower PON1 activity than did the controls (RoM=0.81; 95% CI: 0.74-0.89, p<10(-5)). In the subgroup analyses by CHD end points, a similar effect size was observed with coronary stenosis and myocardial infarction subgroups, with corresponding RoM of 0.81 (95% CI: 0.73-0.89, p<10(-4)) and 0.83 (95% CI: 0.74-0.93, p=0.001), respectively. Decreased PON1 activity associated with CHD risk was observed in almost all subgroup analysis according to ethnicity, sample size, study design, mean age of cases, source, and type of control. Decreased PON1 activity may act as a risk factor for the development of CHD. Progressive decrease in serum PON1 activity may exist for an individual with severe disease. However, larger studies using a prospective approach are needed to confirm our results.

Assessment of paraoxonase 1, xanthine oxidase and glutathione peroxidase activities, nitric oxide and thiol levels in women with polycystic ovary syndrome.

OBJECTIVE: To investigate whether there is any relation between oxidative stress and the antioxidant system in the development of polycystic ovary syndrome (PCOS) by measuring serum nitric oxide (NO) levels and xanthine oxidase (XO) activity (a generator of reactive oxygen species) and antioxidant status by measuring serum thiol levels and glutathione peroxidase (GSHPx) and paraoxonase 1 (PON1) activities. DESIGN: Prospective case-control study. SETTING: University hospital in Turkey. SAMPLE: Thirty women with polycystic ovary syndrome and 20 age- and sex-matched healthy control subjects were included. METHODS: Serum XO, PON1 and GSHPx activity and NO and thiol levels were determined by spectrophotometric methods. MAIN OUTCOME MEASURES: Activity of serum XO, PON1 and GSH, as well as NO and thiol levels. RESULTS: Serum XO activities were higher in women with PCOS than in the control women (p<0.001). The PON1 activity was lower in women with PCOS than in the control women (p<0.001). No significant difference was found between NO and thiol levels and GSHPx activities of women with PCOS and the control women (p>0.05). Serum PON1 activities were negatively correlated with serum XO activities and NO levels. CONCLUSION: Increased oxidant XO activity and decreased lipid antioxidant PON1 activity, along with the observed negative correlation between these parameters, suggests that women with PCOS are under oxidative stress and that there is XO-mediated lipid peroxidation, which may be related to increased atherosclerosis seen in later life in such women.

The role of combined assessment of defense against oxidative stress and inflammation in the evaluation of peripheral arterial disease.

Atherosclerosis in symptomatic peripheral arterial disease affects wide portions of numerous arteries in lower extremities. The resulting active inflammation in a considerable amount of arterial tissue facilitates systemic detection via measurement of inflammation-related variables. We reasoned that the combined assessment of defense against oxidative stress, in the form of paraoxonase-1 (PON1), and monocyte migration measured as circulating (C-C motif) ligand 2 (CCL2), may play a role in the evaluation of these patients. Plasma CCL2 and serum PON1-related variables, assessed by their interaction with functional genetic variants, were measured in a cross-sectional study in patients with symptomatic PAD. We found that PON1 activity and concentration were significantly lower and CCL2 concentration higher in PAD patients compared to controls, that the combination of plasma CCL2 and PON1- related values, especially PON1 concentration differentiated, almost perfectly, controls from patients and that the expression of CCL2 and PON1 generally co-localized in the atherosclerotic lesion. Since no association with genetic variants was found, such a relationship is probably the result of the disease. Our data suggest a coordinated role between CCL2 and PON1 that may be detected in blood with simple measurements and may represent an indicator of the extent of atherosclerosis.

Evaluation of oxidative stress markers in first trimester for assessment of preeclampsia risk.

AIM: The aim of this study is to determine the predictive values of oxidative stress markers and antioxidants in the development of preeclampsia between 10-14 and also at 20-24 weeks of gestation, after the completion of vascular transformation. MATERIALS AND METHODS: Levels of oxidative stress parameters such as malondialdehyde (MDA), lipidhydroperoxide (LHP) and prostaglandin F(2α) (PGF(2α)), oxidized LDL (oxLDL), and antioxidant status parameters such as paraoxonase 1 (PON1), superoxide dismutase (SOD) and total antioxidant capacity (TAC) levels were measured and compared in 21 preeclamptic and 24 healthy pregnant women. RESULTS: In preeclamptic women, both between 10-14 and also at 20-24 weeks of gestation the levels of oxLDL, MDA and PGF(2α) were significantly higher (P < 0.001, P < 0.001, respectively), PON1, SOD and TAC were significantly lower (P < 0.01, P < 0.001, P < 0.05, respectively) compared to healthy pregnant women; yet there was no significant difference in LHP levels. CONCLUSION: Increased levels of serum MDA and PGF(2α), low levels of SOD and PON1 activity, in 10-14 GW may have been associated with preeclampsia etiology. High levels of MDA and PGF(2α) indicate that the oxidative damage is present well before the clinical symptoms occur. A panel of oxidative stress markers such as MDA and PGF(2α) in maternal blood can predict the development of preeclampsia long before clinical onset.

Cardiovascular risk assessment in patients with type 2 diabetes mellitus and metabolic syndrome: role of biomarkers.

OBJECTIVES: Metabolic syndrome (MetS) and type 2 diabetes mellitus (DM) are associated with a high incidence of cardiovascular diseases. The aim of this study was to determine paraoxonase (PON), total sialic acid (TSA), and nitric oxide (NO) levels in addition to conventional risk markers in patients with DM, MetS and DM plus MetS. MATERIAL AND METHODS: The study has been carried out over 78 subjects which divided into four groups; control (n=18), DM (n=20), newly diagnosed MetS (n=20) and DM plus MetS patient groups (n=20). RESULTS: Both insulin and triglyceride concentrations were significantly higher in DM+MetS group than in control and DM groups and serum HDL-C concentrations were significantly lower in DM+MetS group than other groups. Patients with MetS had higher LDL-C, total cholesterol and hsCRP concentrations than in the other groups. Interestingly, in addition to body mass index and waist circumference values, LDL-C, total cholesterol and hsCRP concentrations were decreased in patients who have both DM and MetS. Serum NO and TSA levels were higher in MetS and DM+MetS groups compared to control subjects. Unexpectedly, PON activity has been found lower in control group when compared to other groups. CONCLUSIONS: Although there is no doubt that association of DM and MetS elevates the risk of cardiovascular disease, occurrence of DM in patients with undiagnosed MetS might be encouraging patients to change their life styles and dietary habits.