Tu-P10:498 A proposed new comprehensive index of oxidative stress: Oxiscore

Tues&ty, June 20, 2006: Poster Session PIO Biomarkers for cardiovascular disectse

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lipids, transferrin saturation (TSAT), ferritin, and C-reactive protein (hs-CRP) was performed at baseline, after 3 months and, in HD patients, after 6 months. Lipid oxidation was assessed by measuring plasma malondialdehyde (MDA) concentration by HPLC. Results: In HD patients, median serum A A increased from 0.22 to 0.63 mg/dl (P<0.001) while a 26% increase was observed in plasma MDA from 1.50 4- 0.36 (baseline) to 1.89 4- 0.50 I~mol/1 after 3 months (P<0.001). After vitamin C supplements were stopped, A A and MDA returned to baseline concentrations after 6 months. MDA after 3 months positively correlated with ferritin (r=0.425, P<0.001), A A (r=0.307,P=0.003), and triglycerides (r=0.199, P=0.043) but not with other lipids, TSAT, or hs-CRR Significant changes in MDA were not observed in the CAPD group. Conclusions: Plasma MDA paradoxically increases by oral vitamin C supplementation in iron- and EPO-treated HD patients. This observation can be attributed to a pro-oxidant effect of vitamin C since A A releases Fe(II) from ferritin, and Fe(II) can induce lipid oxidation. The safety of vitamin C administration in iron-treated HD patients needs further study. I

I Tu-P10:495 I S E R U M L E V E L OF S O L U B L E R E C E P T O R F O R i A D V A N C E D G L Y C A T I O N E N D P R O D U C T S IS ASSOCIATED WITH CIRCULATING ADVANCED G L Y C A T I O N E N D P R O D U C T S IN T Y P E 2 D I A B E T E S

K.C.B. Tan I , W.S. Chow 1 , S.W.M. Shiu 1 , R. Bucala 2 , D.J. Betteridge 3 .

1Department of Medicine, University of Hong Kong, Hong Kong." 2 Yale Universi~ School of Medicine, Yale, USA." 3Royal Free & Universi~ College London Medical School, London, United Kingdom Objective: Activation of the receptor for advanced glycation end products (RAGE) has been implicated in atherosclerosis and inflammatory diseases. Blockade of RAGE using a soluble form of the receptor (sRAGE) suppressed vascular hyperpermeability and atherosclerosis in animal models. Since little is known about the regulation of endogenous sRAGE levels, we determine whether serum sRAGE is influenced by circulating advanced glycation end products (AGEs) and chronic inflammation in type 2 diabetes (DM). Methods: 323 DM subjects were recruited and divided into those with proteinuria (P), microalbuminuria (MA) or normoalbuminuria (NA). Serum sRAGE was assayed by an E L I S A kit (R&D Systems); serum AGEs by competitive ELISA using a polyclonal rabbit antisera raised against AGE-RNase; and high sensitivity C-reactive protein (CRP) by immunoturbidimetric assay. Results: Proteinuric subjects had the highest sRAGE level (P: 1251-4-701 pg/ml, MA: 1114-4-547; NA: 1013-4-418, ANOVA p=0.008). Serum AGEs and CRP were also highest in P (p<0.001). Serum sRAGE correlated with AGEs (r--0.28, p < 0.001), log(plasma creatinine) (r=0.31, p < 0.001), log(triglyceride) (r=0.14, p=0.01) but not with CRE On linear regression analysis, AGEs and creatinine levels were the main determinants of sRAGE independent of age, sex, body mass index, smoking, triglyceride and DM duration. Conclusion: Serum sRAGE may be influenced by circulating AGEs levels and renal function but not by the extent of inflammation in DM. Whether AGEs can directly affect sRAGE production warrants further investigation. Funding: Hong Kong Research Grants Council (HKU7350/02).

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I Tu-P 10:497 I O X I D A T I V E M O D I F I E D F I B R I N O G E N A S M A R K E R O F O X I D A T I V E S T R E S S IN M Y O C A R D I A L INFARCTION i

Y.I. Ragino, V.A. Baum, A.A. Gromov. Institute oflntemal Medicine Sb

Rams, Novosibirsk, Russia Oxidative stress is one of the main pathogenic compounds of coronary heart disease (CHD) and myocardial infaxction (MI). The aim of the study was to investigate the relationships between oxidative modified fibrinogen, activity of lipid peroxidation (LPO) process and disturbances of hemostasis system in patients with MI and to evaluate the diagnostic significance of oxidized fibrinogen detection. Thirty nine men with CHD and subacute MI (group-l) and 42 men of a similar age group without CHD (group-2) were included into the study. The simple method for evaluation of oxidative modified fibrinogen, including fast isolation of fibrinogen from plasma and spectrophotometrical detection of carbonyl groups content, was worked out (patent of Russia, 2005). Parameters of LPO process in plasma and in low-density lipoproteins (LDL) were determined as TBARS. The levels of LDL hydroperoxides were evaluated after lipid phase extraction from LDL with heptane-isopropanol (1:1). The levels of plasma fibrinogen were similar in two groups. However, extent of oxidative modified fibrinogen was significantly 4 times higher (p<0,001) in men with subacute MI versus men without CHD. Positive independent

associations of higher oxidative modified fibrinogen with MI were revealed (p<0,001). Parameters of LPO process in plasma, in LDL and the levels of LDL hydroperoxides were significantly higher (1,4, 2,2 and 1,9 times, respectively, p<0,001) in group-1 men versus control group. Men with MI had also the increased activity of antithrombine III, thrombin inactivation index and significantly decreased activity of XIIa-dependent fibrinolysis as compared with group-2 men. Strong positive correlation between parameters of LPO process in plasma and degree of oxidative modification of fibrinogen was found (r=0,611, p<0,001). Obtained results indicate that oxidative modified fibrinogen, equally with LPO level, is one of the new markers of oxidative stress in CHD and MI.

ITu-P10:4981

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A P R O P O S E D N E W C O M P R E H E N S I V E I N D E X OF OXIDATIVE STRESS: OXISCORE

F. Veglia 1, G. Cighetti 2 , L. Zingaxo 1 , E. Tremoli 3, V. Cavalca 4 . 1Centro

Cardiologico Monzino, Milan, Italy: 2Dept of Medical Chem Biochem Univ Milan, Milan, Italy: 3Dept of Pl~trm Sci Univ Milan, Milan, Italy: 4btst of Cardiology Univ Milan, Milan, Italy Objective: Oxidative stress has been related both to the aging process and to several pathologies, like cancer and cardiovascular disease. Up to now, no ideal biomaxker for oxidative stress is available. This study was performed to identify a comprehensive index of oxidative status (OXISCORE) reflecting both injuries and antioxidant defences in vivo. Methods: We enrolled and stratified by age and gender, 87 healthy subjects (59% males; age 24-77) and 20 CAD patients (65% males; age 47-81). Plasma free and total malondialdehyde (F- and T-MDA), glutathione disulphide/reduced forms (GSSG/GSH) and urine isoprostane (iPF2alpha-III) levels were measured as markers of oxidative damage, and computed in the damage score (DS). Plasma glutathione, alpha- and gamma-tocopherol (TH) levels, and individual antioxidant capacity (IAC), were measured as indexes of antioxidant defence, and computed in the protection score (PS). OXISCORE was computed by subtracting PS from DS. Results: In healthy subjects, only MDA was associated with age; only GSH, GSSG/GSH ratio and alpha-TH correlated with gender. OXISCORE, was positively associated with both age (p=0.007) and male gender (p=0.01). Interestingly, OXISCORE was significantly higher in CAD subjects even after adjusting for age and gender (p=0.0001). Conclusions: No single parameter fully reflects the redox status. By representing both antioxidant and oxidative systems, the OXISCORE provides a comprehensive index of oxidative stress related to age, gender and CAD status. Funding: Grant from Italian Ministry of Health

ITu-P10:4991LC YL ISNOIPCHAOLS IPMHPALTIICDAYTLICOHNOOLFI NCEI RINC UTLYAPTEI N2 G D I A B E T I C S : R O L E OF S E R U M H Y D R O L Y T I C ESTERASES Y. Kumon 1, S. Yamanaka 1 , Y. Ikeda 2 , H. Takeuchi 1 , M. Inoue 2, K. Arii 2, T. Suehiro 2, K. Hashimoto 2, T. Sugiura 1 . 1Dpt of Laboratory Medicine,

Kochi Medical School, Nankoku Kochi, Japan." 2Dpt of EtMocrinology, Metabolism arm Nephrology, Kochi Medical School, Nankoku Kochi, Japan Objective: Lysophosphatidylcholine (LPC), a major constituent of oxidized low-density lipoprotein (oxLDL), is considered as an oxidative marker. However, clinical implication of LPC and oxLDL is not determined. The aim of this study was to clarify the clinical significance of circulating LPC and oxLDL, and their relationship to serum hydrolytic enzymes in diabetes. Methods: Circulating LPC and oxLDL were measured in 147 patients with type 2 diabetes. We also evaluated serum esterase levels of paxaoxonase-1 (PON-1, paxaoxonase and arylesterase activities), platelet-activating factor acetylhydrase (PAF-AH), and secretary type phospholipase A2, all of which theoretically generate LPC in the body. Results: There was no significant correlation between plasma LPC and oxLDL. Both LPC and oxLDL concentrations correlated with LDLcholesterol(C) concentration, arylesterase and PAF-AH activities, but not with H b A l c level. LPC and arylesterase levels, but not oxLDL, were lower in patients with vascular complications. Stepwise multiple regression analysis revealed that LDL-C level accounted for most of the variations in oxLDL level, and that development of vascular complications was a negative determinant and axylesterase activity was a positive determinant of LPC level. Conclusions: The clinical implication of circulating levels of LPC and oxLDL were not identical, and LPC level was lower in type 2 diabetics

XIV bzten~ttional Symposium on Atherosclerosis, Rome, Italy, June 18-22, 2006