- Email: [email protected]
Mo-W7:1 Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, acts as a novel cardiovascular risk factor
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Momlay, June 19, 2006: Workshop Biomarkers for risk determbzation: novel risk factors
ENDOTHELIAL PROTEIN C PATHWAY MODULATES NEUTROPHIL INFLAMMATORY E V E N T S
Q. Zheng, S. Kurosawa, D.J. Steaxns-Kurosawa. Oklahoma Medical Researeh
Foundation, Oklahoma City, USA Objectives: Soluble endothelial protein C receptor (sEPCR) is released from endothelium after thrombin generation and epidemiological studies show elevated sEPCR levels axe a risk factor for cardiovascular disease, sEPCR binds to activated neutrophils via proteinase-3 (PR3), a neutrophil serine protease, and beta2 integrin. PR3 cleaves tumor necrosis factor precursor to release pro-inflammatory TNFa. This study examined localization of sEPCR on neutrophils, and the influence of sEPCR on activity of neutrophil enzymes. Methods: ELISAs measured proteolytic TNFa release from stably transfected TNF precursor-CHO cells and soluble thrombomodulin from HUVECs. TNFa degradation +/- PR3, elastase (HLE) or sEPCR was determined by western blotting or ELISA. Confocal microscopy and ultracentrifugation studies examined localization of PR3, sEPCR nad lipid raft markers on neutrophils. Results: PR3 and HLE degraded TNFa; this was inhibited by sEPCR (0-5uM). At 0.5uM sEPCR, PR3 activity was inhibited by 33.6% and HLE by 54.6%. sEPCR did not alter cleavage of TNF precursor by PR3 or endothelial thrombomodulin by HLE. sEPCR did not change PR3 or HLE amidolytic activity. PR3 and sEPCR co-localized with lipid microdomaJn markers cholera toxin B, CD 18 and flotillin- 1 on activated neutrophils. Conclusions: sEPCR localizes to ra£t-like structures on neutrophils where it interacts with serine proteases other than activated protein C to alter macromolecular specificity and modulate cytokine bioavaJlability. This may be important for an appropriate and controlled local inflammatory response. Funding: NIH RR020143, Pfizer A R A (DSK)
Mo-W6:6
AUGMENTED LEVELS OF CD44 IN MACROPHAGES FROM ATHEROSCLEROTIC SUBJECTS: A POSSIBLE IL-6 - CD44 FEEDBACK LOOP?
S. Sloberg-, D. Hagg I , L. Mattson Hulten-, B. Fagerberg-, O. Wiklund-, A. Rosengren 3, L.M.S. Carlsson 1 , J. Boren-, E-A. Svensson "-, A. Krettek-.
1Researeh Center For Endocrinology & Metabolism, Shalgrenska Academy At Goteborg Universi~, Goteborg, Sweden." 2 Wallenberg [xtboratot y For Cardiovascular Researeh, Sahlgrenska AccMemy At Goteborg University, Goteborg, Sweden." 3Dept. of Acute arm Cardiovascular Medicine, Sahlgrenska Academy At Goteborg Universi~, Goteborg, Sweden Objective: Cell-adhesion molecule CD44 likely participates in atherosclerosis development. We have shown previously that pro-inflammatory cytokines aYfect CD44 expression. Hence, this work examined the role of elevated CD44 levels in human macrophages (MO). Methods: We matched atherosclerotic subjects with control subjects and then searched for atherosclerosis susceptibility genes by performing expression profiling of primary MO. Genotyping of single nucleotide polymorphisms (SNP) was performed in 561 cases and 570 controls. The impact of cytokines, initially examined by a cytokine screen on plasma from CD44-deficient and wild-type mice, showed a difference in IL-6 concentrations. We then measured IL-6 in cell culture supernatants and serum from subjects with and without atherosclerosis. Finally, we examined if IL-6 stimulates CD44 production in human MO. Results: MO from atherosclerotic subjects showed 1.5-fold elevated levels of CD44 transcript (P=0.050) and protein (P=0.044) compared to controls. The two SNP in the CD44 gene were not associated with coronary artery disease. Elevated CD44 expression correlates (P = 0.012) with enhanced MO IL-6 secretion (3.13 -4- 2.5 pg/mL vs. 0.32 -4- 0.16 pg/mL in controls, P=0.021). Furthermore, IL-6 augments CD44 expression in primary human MO after 24 (P=0.038) and 48 hours (P=0.015). Conclusions: Taken together, our data show an IL-6 - CD44 feedback loop in MO. Elevated CD44 expression in MO from atherosclerotic subjects suggests that this loop may participate importantly in atherogenesis. Funding: Swedish Research Council, Swedish Heart-Lung Foundation, Ake Wiberg's Foundation.
CHOLESTEROL CRYSTALS RUPTURE PLAQUES DURING MYOCARDIAL INFARCTION G. Abela, K. Aziz. Michigan State Universi~, East [xmsing, ML USA
Objective: To elucidate the mechanism of plaque rupture we evaluated the effect of cholesterol crystal formation from a liquid to solid state in an in vitro model and compared it to human coronary artery following acute myocardial
infaxction. We hypothesize that cholesterol crystallization causes rapid and forceful expansion that can damage the plaque caps. Metbods: Two in vitro experiments were performed; first, cholesterol powder was melted in graduated cylinders and allowed to crystallize at room temperature. Volume changes from a liquid to solid state were measured and timed. Second, thin fibrous biological membranes, rabbit pericardium and mesentery (10-40 I~m thick) were put in the path of growing crystals to determine damage by crystallization. Scanning electron microscopy (SEM) was performed on membranes and fresh human coronary artery from necropsy while avoiding use of solvents. Results: As cholesterol crystallized, the peak volume increased rapidly by up to 45% over 3 rain and sharp tipped crystals tore through membranes. The amount of cholesterol was directly related to the level and rate of crystal growth (r = 0.98; r = 0.99; p<0.01, respectively). SEM of human coronary artery demonstrated crystals tearing through the intima at and near the rupture site similar to findings in biological membranes. Conclusions: As cholesterol crystallized, the occupied volume expanded rapidly and sharp tipped crystals tore through membranes. The amount of cholesterol was directly related to the extent and rate of crystal growth. Human coronary artery demonstrated crystals tearing through the intima at and near the plaque rupture site as seen in biological membranes. These findings greatly elucidate the mechanism of plaque rupture and thrombosis. Funding: Michigan State University; American Society for Lasers in M e d i d n e and Surgery; National Institutes of Health.
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BIOMARKERS FOR RISK DETERMINATION: NOVEL RISK FACTORS ASYMMETRICDIMETHYLARGININE(ADMA), AN ENDOGENOUS INHIBITOR OF NITRIC OXIDE SYNTHASE, ACTS AS A NOVEL CARDIOVASCULAR RISK FACTOR
R.H. B6ger. b~stitute of Eapet4mental and Cl#dcal Pharntacology, Universi~ Hospital Hmnburg-Eppendotf Hmnburg, Get'many Experimental and clinical evidence has recently accumulated that A D M A is an endogenous competitive inhibitor of NO synthase. A D M A inhibits vascular NO production in pathophysiological concentrations; A D M A also causes local vasoconstriction when it is infused intraaxterially. A D M A is increased in plasma of humans with hypercholesterolemia, atherosclerosis, hypertension, chronic renal failure, chronic heart failure, and other clinical entitites. Increased A D M A levels are associated with reduced NO synthesis as assessed by impaired endothelium-dependent vasodilation. In several prospective and cross-sectional studies, A D M A has evolved as a marker of cardiovascular risk. Moreover, prospective clinical studies have suggested that A D M A may play a role as a novel cardiovascular risk factor. In 2001, we were the first to show that elevated A D M A is associated with a 3-fold increased risk of future severe cardiovascular events and total mortality in hemodialysis patients. Valkonen and co-workers demonstrated in a nested case-control study that elevated A D M A was associated with a 4-fold elevated risk for acute coronary events in clinically healthy, non-smoking men. In patients with stable angina pectoris, pre-interventional A D M A indicates the risk of developing restenosis or severe clinical events after coronary intervention; likewise, A D M A indicates the prognosis of patients in acute coronary syndrome. Furthermore, in humans with no underlying cardiovascular disease undergoing intensive care unit (ICU) treatment, A D M A is a marker of the mortality risk during ICU treatment. We recently extended the latter finding by showing in a prospective study design that in humans undergoing major thoracic or abdominal surgery, pre-operative A D M A levels can predict the incidence of developing major post-operative complications. Pathophysiological evidence has recently become available from transgenic and knockout mouse models, which support a causative role of A D M A in regulating endothelial function, vascular resistance, and vascular disease. In summary, an increasing number of prospective clinical trials have shown that the association between elevated A D M A levels and major cardiovascular events and total mortality is robust and extends to diverse patient populations. However, we need to define more clearly in the future who will profit from A D M A determination, in order to more specifically use this novel risk marker as a diagnostic tool. References [1] Zoccali C, Bode-B6ger SM, Mallamaci F, Benedetto FA, Tripepi G, Malatino L, Cataliotti A, Bellanuova I, F e r r e t I, Fr61ich JC, B6ger RH. Asymmetric dimethylarginine (ADMA): An endogenous inhibitor of ni-
XIV bztetTmtional Symposium on Atherosclerosis, Rome, Italy, June 18-22, 2006
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[3]
[4]
[5]
Momlay, June 19, 2006: Workshop Biomarkers for risk determination: novel risk factors
tric oxide synthase predicts mortality in and-staga ranal disease 0ESRD). Lancat. 2001; 358:2113-2117 Schulza F, Wasamann R, Schwadhalm E, Sydow K, Albsmaiar J, Cooka JE B6gar RH. Datarmination of A D M A using a noval ELISA assay. Clin. Chain. Lab. Mad. 2004; 42:1377-1383 Schulza F, Maas R, Fraasa R, Schwadhalm E, Silbarhorn L, B6gar RH. Datarmination of a rafaranca valua for N,N-dimathyl-L-axginina in 500 subjacts. Eur. J. Clin. Invast. 2005; 35:622-626 Schwadhalm E, Tan-Andrasan J, Maas R, Riadarar U, Schulze F, B6gar RH. LC-tandam MS mathod for tha analysis of asymmatric dimathylaxginina (ADMA) in human plasma. Clin. Cham. 2005; 51:1268-1271 B6gar RH. Asymmatric dimathylarginina (ADMA): a noval risk markar in cardiovascular madicina and bayond. Ann. Mad. 2006 fin prass)
I Mo-W7:2 ] PARTICULATE AIR POLLUTION A N D ATHEROSCLEROTIC CARDIOVASCULAR DISEASE R.D. Brook. Division of Cardiovascular Medicbte, Universi~ of Michigan,
Ann Arbor; Michigan, USA Objective: To raviaw tha sciantific avidanca linking particulate mattar (PM) air pollution to an incraasad risk of cardiovascular disaasas. Methods: Litaratura raviaw Results: PM air pollution is a complax, hataroganaous mixtura of aarosols that wxy in size from savaral nanomatars (PM0.1), through fina PM <2.5 I~m (PM2.5), to coarsa PM batwaan 2.5 and 10 I~m in diamatar (PM10). Tha avidanca most strongly links PM2.5 to advarsa cardiovascular (CV) haalth affacts; howavar more racant findings also implicata ultrafina (PM0.1) PM. In tha modarn world, most PM2.5 is darivad from urban fossil fuel combustion, industry, and from mobila sourcas such as automobilas and diasal axhaust. Tha chamical composition of tha PM mixtura may play a role in datarmining tha haalth impact. Individuals with pra-axisting heart or lung disaasa and diabatas may ba at highar CV risk dua to tha affacts of PM. Epidamiological studias conductad throughout tha world have confirmad a consistant, gradad association batwaan PM axposura and incraasad risk for CV avants. Short-tarm (hours-to-days) axposura incraasas tha risk for acute (1-5 days) CV mortality by 0.31 to approximataly 1.0% par 10 i~g/m3 alavation in PM10. Tha risk for acute myocardial infarction has been shown to incraasa by as much as 48% within 2 hours (par 25 i~g/m3 incraasa in PM2.5) in Boston. Studias in Rome and Europa confirm tha association batwaan acute myocardial infaxction and also ra-infaxction with axposura to PM. Automobila sourcas of PM may ba particularly harmful, incraasing tha risk for myocardial infaxction by 2.9-fold within 1 hour. PM may also triggar stokas. Studias assassing tha long-tarm affacts of PM axposura damonstrata an even graatar affact on CV risk. Sixtaan year axposura to alavatad PM2.5 incraasas tha mortality due to CV disease (RR 1.12), ischemic heart disaasa (RRI.18), and axrhythmia/haart faJlura/caxdiac arrast (RR 1.13). Savaral machanisms have now been dascribad that may axplain tha biological pathways rasponsibla. PM axposura could play a role in atharosclarotic CV disaasa at all stagas: from promoting tha davalopmant of traditional CV risk factors (a.g. hypartansion), to diracdy facilitating tha ganasis of atharosclarosis (a.g. vascular inflammation), to triggaring acute plaqua ruptura and instigating suddan avants (a.g. vasoconstriction, anhancad thrombosis). In ganaral, tha pulmonary inhalation of PM could aYfact tha systamic vasculatura by ganarating local lung tissua oxidativa strass/inflammation with tha subsaquant spill-ovar of activatad cells and pro-inflammatory madiators; by diracdy altaring autonomic balanca through intaracting with pulmonary racaptors; and/or by diract affacts on tha vasculatura by PM or solubla constituants capabla of raaching tha circulation. PM has been shown to triggar acute arterial vasoconstriction and andothalial dysfunction, possibly as a rasult of oxidativa strass, that could chronically promota atharosclarosis and acutaly triggar ischamia. Other studias show incraasad systamic inflammation, anhancad thrombosis/coagulation, and autonomic imbalanca dua to PM inhalation. Racantly, axparimants in both animals and humans corroborata that tha chronic axposura to PM can actually promota tha ganasis of atharosclarosis itsalf. Conclusions: Both short and long-tarm axposura to PM air pollution is linkad to incraasa risk of CV disaasa. PM is capabla of both triggaring acute CV avants and promoting tha davalopmant of atharosclarosis via savaral machanistic pathways. References [1] Brook RD, Franklin B, Cascio W, at al. Air pollution and cardiovascular disaasa. A statement for haalthcara professionals from tha expert panel on population and prevention science of tha American Heart Association. Circulation 2004; 109: 2655-71.
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HOXA9 AND FLK1 E X P R E S S I O N IN CD34+ PERIPHERAL CELLS OF HYPERTENSIVE PATIENTS CORRELATES WITH THE NUMBER OF CIRCULATING E N D O T H E L I A L P R O G E N I T O R CELLS
M. Pirro, C. Manacali, F. Bagaglia, M.R. Mannaxino, G. Schillaci, E. Mannarino. InterTtal Medicbw, Angiology attd Arteriosclerosis Diseases,
Perugia, Italy Objective: HoxA9, a critical regulator of postnatal neovasculaxization and endothelial commitment during progenitor cell maturation, is essential for the expression of the endothelial-committed genes (ex. F l k l ) . We investigated whether in hypertensive patients CD34+ cells expression of HoxA9 and F l k l is impaired and if a correlation exists between the expression of these genes and the number of circulating endothelial progenitor cells. Methods: 20 patients with never-treated essential hypertension and 10 ageand sex-matched normal controls were recruited for the study. Total RNA was isolated from circulating CD34+ cells and subjected to quantitative RT-PCR for measurement of HoxA9 and F l k l expression. The number of endothelial progenitor cells was measured after PBMC isolation, staining with anti-CD34 and anti-Flkl fluorescent antibodies and flow-citometry analysis. Results: hypertensive patients had a reduced expression of HoxA9 and F l k l genes compared to normotensive subjects. In addition, the number of peripheral CD34+ cells and that of circulating endothelial progenitor cells was significantly lower in hypertensive than in normotensive subjects. Intarastingly, a direct correlation was obsarvad batwaan CD34+ cells gene axprassion of HoxA9 and F l k l , on tha ona hand, and tha numbar of andothalial proganitors, on tha other hand. Conclusions: in hypartansiva patiants, a down-regulation of paripharal CD34+ cells HoxA9 and F l k l gana axprassion may contributa to raduca tha numbar of circulating andothalial proganitor calls, thus potantially impairing postnatal naovascularization and vascular reparation.
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A S Y M M E T R I C D I M E T H Y L A R G I N I N E ( A D M A ) IS A S S O C I A T E D W I T H I N C I D E N T CARDIOVASCULAR D I S E A S E IN T H E G E N E R A L P O P U L A T I O N . T H E H O O R N STUDY
T. Taarlink, R.J. Heine, G. Nijpals, L.M. Boutar, C.D.A. Stahouwar, J.M. Dakkar. Institute For Cardiovascular Researeh, VU Universi~ Medical
Center: Amsterdam, the Netherlands Objective: Incraasad asymmatric dimathylaxginina (ADMA), an andoganous inhibitor of nitric oxide synthasa, pradicts cardiovascular disaasa (CVD) in high-risk patiant groups. Wa have prospactivaly studiad tha association batwaan A D M A and CVD in tha ganaral population. Methods: Tha Hoorn Study, a community-basad prospactiva cohort study, startad in 1989. Plasma A D M A at basalina was maasurad by HPLC in 1707 subjacts (aga 50 to 75 yaars, 158 with type 2 diabatas). Tha main outcoma maasura was tha combinad incidanca of fatal and non-fatal CVD during 10-yaax follow-up. Tha ralation batwaan A D M A and CVD was axaminad with Cox proportional hazards modals. Results: During follow-up, 389 subjacts (68 with diabatas) axpariancad a cardiovascular avant. Tha ralation batwaan A D M A and CVD was not continuous but rastrictad to tha highast quintila. After adjusting for aga, gandar and astablishad risk factors (cholastarol, HDL-cholastarol, body mass indax, renal function, hypartansion, smoking, glucosa and pravalant CVD) a high plasma concantration of A D M A fi.a. highast quintila varsus lowast four quintilas) was associatad with a hazard ratio for CVD of 1.49 (95% C.I., 1.16 to 1.90) in subjacts without diabatas and 0.48 (0.24 to 0.98) in subjacts with diabatas. In analysas rastrictad to participants without diabatas and CVD at basalina, tha hazard ratio was 1.40 (1.02 to 1.91). Conclusion: A high plasma concantration of A D M A indapandantly pradicts CVD in subjacts without type 2 diabatas. Tha invarsa ralation batwaan high A D M A and CVD in subjacts with diabatas needs confirmation in other populations.
XIV bzterTmtional Symposium on Atherosclerosis, Rome, Italy, June 18-22, 2006
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Momlay, June 19, 2006: Workshop Biomarkers for risk determbzation: novel risk factors
ENDOTHELIAL PROTEIN C PATHWAY MODULATES NEUTROPHIL INFLAMMATORY E V E N T S
Q. Zheng, S. Kurosawa, D.J. Steaxns-Kurosawa. Oklahoma Medical Researeh
Foundation, Oklahoma City, USA Objectives: Soluble endothelial protein C receptor (sEPCR) is released from endothelium after thrombin generation and epidemiological studies show elevated sEPCR levels axe a risk factor for cardiovascular disease, sEPCR binds to activated neutrophils via proteinase-3 (PR3), a neutrophil serine protease, and beta2 integrin. PR3 cleaves tumor necrosis factor precursor to release pro-inflammatory TNFa. This study examined localization of sEPCR on neutrophils, and the influence of sEPCR on activity of neutrophil enzymes. Methods: ELISAs measured proteolytic TNFa release from stably transfected TNF precursor-CHO cells and soluble thrombomodulin from HUVECs. TNFa degradation +/- PR3, elastase (HLE) or sEPCR was determined by western blotting or ELISA. Confocal microscopy and ultracentrifugation studies examined localization of PR3, sEPCR nad lipid raft markers on neutrophils. Results: PR3 and HLE degraded TNFa; this was inhibited by sEPCR (0-5uM). At 0.5uM sEPCR, PR3 activity was inhibited by 33.6% and HLE by 54.6%. sEPCR did not alter cleavage of TNF precursor by PR3 or endothelial thrombomodulin by HLE. sEPCR did not change PR3 or HLE amidolytic activity. PR3 and sEPCR co-localized with lipid microdomaJn markers cholera toxin B, CD 18 and flotillin- 1 on activated neutrophils. Conclusions: sEPCR localizes to ra£t-like structures on neutrophils where it interacts with serine proteases other than activated protein C to alter macromolecular specificity and modulate cytokine bioavaJlability. This may be important for an appropriate and controlled local inflammatory response. Funding: NIH RR020143, Pfizer A R A (DSK)
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AUGMENTED LEVELS OF CD44 IN MACROPHAGES FROM ATHEROSCLEROTIC SUBJECTS: A POSSIBLE IL-6 - CD44 FEEDBACK LOOP?
S. Sloberg-, D. Hagg I , L. Mattson Hulten-, B. Fagerberg-, O. Wiklund-, A. Rosengren 3, L.M.S. Carlsson 1 , J. Boren-, E-A. Svensson "-, A. Krettek-.
1Researeh Center For Endocrinology & Metabolism, Shalgrenska Academy At Goteborg Universi~, Goteborg, Sweden." 2 Wallenberg [xtboratot y For Cardiovascular Researeh, Sahlgrenska AccMemy At Goteborg University, Goteborg, Sweden." 3Dept. of Acute arm Cardiovascular Medicine, Sahlgrenska Academy At Goteborg Universi~, Goteborg, Sweden Objective: Cell-adhesion molecule CD44 likely participates in atherosclerosis development. We have shown previously that pro-inflammatory cytokines aYfect CD44 expression. Hence, this work examined the role of elevated CD44 levels in human macrophages (MO). Methods: We matched atherosclerotic subjects with control subjects and then searched for atherosclerosis susceptibility genes by performing expression profiling of primary MO. Genotyping of single nucleotide polymorphisms (SNP) was performed in 561 cases and 570 controls. The impact of cytokines, initially examined by a cytokine screen on plasma from CD44-deficient and wild-type mice, showed a difference in IL-6 concentrations. We then measured IL-6 in cell culture supernatants and serum from subjects with and without atherosclerosis. Finally, we examined if IL-6 stimulates CD44 production in human MO. Results: MO from atherosclerotic subjects showed 1.5-fold elevated levels of CD44 transcript (P=0.050) and protein (P=0.044) compared to controls. The two SNP in the CD44 gene were not associated with coronary artery disease. Elevated CD44 expression correlates (P = 0.012) with enhanced MO IL-6 secretion (3.13 -4- 2.5 pg/mL vs. 0.32 -4- 0.16 pg/mL in controls, P=0.021). Furthermore, IL-6 augments CD44 expression in primary human MO after 24 (P=0.038) and 48 hours (P=0.015). Conclusions: Taken together, our data show an IL-6 - CD44 feedback loop in MO. Elevated CD44 expression in MO from atherosclerotic subjects suggests that this loop may participate importantly in atherogenesis. Funding: Swedish Research Council, Swedish Heart-Lung Foundation, Ake Wiberg's Foundation.
CHOLESTEROL CRYSTALS RUPTURE PLAQUES DURING MYOCARDIAL INFARCTION G. Abela, K. Aziz. Michigan State Universi~, East [xmsing, ML USA
Objective: To elucidate the mechanism of plaque rupture we evaluated the effect of cholesterol crystal formation from a liquid to solid state in an in vitro model and compared it to human coronary artery following acute myocardial
infaxction. We hypothesize that cholesterol crystallization causes rapid and forceful expansion that can damage the plaque caps. Metbods: Two in vitro experiments were performed; first, cholesterol powder was melted in graduated cylinders and allowed to crystallize at room temperature. Volume changes from a liquid to solid state were measured and timed. Second, thin fibrous biological membranes, rabbit pericardium and mesentery (10-40 I~m thick) were put in the path of growing crystals to determine damage by crystallization. Scanning electron microscopy (SEM) was performed on membranes and fresh human coronary artery from necropsy while avoiding use of solvents. Results: As cholesterol crystallized, the peak volume increased rapidly by up to 45% over 3 rain and sharp tipped crystals tore through membranes. The amount of cholesterol was directly related to the level and rate of crystal growth (r = 0.98; r = 0.99; p<0.01, respectively). SEM of human coronary artery demonstrated crystals tearing through the intima at and near the rupture site similar to findings in biological membranes. Conclusions: As cholesterol crystallized, the occupied volume expanded rapidly and sharp tipped crystals tore through membranes. The amount of cholesterol was directly related to the extent and rate of crystal growth. Human coronary artery demonstrated crystals tearing through the intima at and near the plaque rupture site as seen in biological membranes. These findings greatly elucidate the mechanism of plaque rupture and thrombosis. Funding: Michigan State University; American Society for Lasers in M e d i d n e and Surgery; National Institutes of Health.
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BIOMARKERS FOR RISK DETERMINATION: NOVEL RISK FACTORS ASYMMETRICDIMETHYLARGININE(ADMA), AN ENDOGENOUS INHIBITOR OF NITRIC OXIDE SYNTHASE, ACTS AS A NOVEL CARDIOVASCULAR RISK FACTOR
R.H. B6ger. b~stitute of Eapet4mental and Cl#dcal Pharntacology, Universi~ Hospital Hmnburg-Eppendotf Hmnburg, Get'many Experimental and clinical evidence has recently accumulated that A D M A is an endogenous competitive inhibitor of NO synthase. A D M A inhibits vascular NO production in pathophysiological concentrations; A D M A also causes local vasoconstriction when it is infused intraaxterially. A D M A is increased in plasma of humans with hypercholesterolemia, atherosclerosis, hypertension, chronic renal failure, chronic heart failure, and other clinical entitites. Increased A D M A levels are associated with reduced NO synthesis as assessed by impaired endothelium-dependent vasodilation. In several prospective and cross-sectional studies, A D M A has evolved as a marker of cardiovascular risk. Moreover, prospective clinical studies have suggested that A D M A may play a role as a novel cardiovascular risk factor. In 2001, we were the first to show that elevated A D M A is associated with a 3-fold increased risk of future severe cardiovascular events and total mortality in hemodialysis patients. Valkonen and co-workers demonstrated in a nested case-control study that elevated A D M A was associated with a 4-fold elevated risk for acute coronary events in clinically healthy, non-smoking men. In patients with stable angina pectoris, pre-interventional A D M A indicates the risk of developing restenosis or severe clinical events after coronary intervention; likewise, A D M A indicates the prognosis of patients in acute coronary syndrome. Furthermore, in humans with no underlying cardiovascular disease undergoing intensive care unit (ICU) treatment, A D M A is a marker of the mortality risk during ICU treatment. We recently extended the latter finding by showing in a prospective study design that in humans undergoing major thoracic or abdominal surgery, pre-operative A D M A levels can predict the incidence of developing major post-operative complications. Pathophysiological evidence has recently become available from transgenic and knockout mouse models, which support a causative role of A D M A in regulating endothelial function, vascular resistance, and vascular disease. In summary, an increasing number of prospective clinical trials have shown that the association between elevated A D M A levels and major cardiovascular events and total mortality is robust and extends to diverse patient populations. However, we need to define more clearly in the future who will profit from A D M A determination, in order to more specifically use this novel risk marker as a diagnostic tool. References [1] Zoccali C, Bode-B6ger SM, Mallamaci F, Benedetto FA, Tripepi G, Malatino L, Cataliotti A, Bellanuova I, F e r r e t I, Fr61ich JC, B6ger RH. Asymmetric dimethylarginine (ADMA): An endogenous inhibitor of ni-
XIV bztetTmtional Symposium on Atherosclerosis, Rome, Italy, June 18-22, 2006
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[2]
[3]
[4]
[5]
Momlay, June 19, 2006: Workshop Biomarkers for risk determination: novel risk factors
tric oxide synthase predicts mortality in and-staga ranal disease 0ESRD). Lancat. 2001; 358:2113-2117 Schulza F, Wasamann R, Schwadhalm E, Sydow K, Albsmaiar J, Cooka JE B6gar RH. Datarmination of A D M A using a noval ELISA assay. Clin. Chain. Lab. Mad. 2004; 42:1377-1383 Schulza F, Maas R, Fraasa R, Schwadhalm E, Silbarhorn L, B6gar RH. Datarmination of a rafaranca valua for N,N-dimathyl-L-axginina in 500 subjacts. Eur. J. Clin. Invast. 2005; 35:622-626 Schwadhalm E, Tan-Andrasan J, Maas R, Riadarar U, Schulze F, B6gar RH. LC-tandam MS mathod for tha analysis of asymmatric dimathylaxginina (ADMA) in human plasma. Clin. Cham. 2005; 51:1268-1271 B6gar RH. Asymmatric dimathylarginina (ADMA): a noval risk markar in cardiovascular madicina and bayond. Ann. Mad. 2006 fin prass)
I Mo-W7:2 ] PARTICULATE AIR POLLUTION A N D ATHEROSCLEROTIC CARDIOVASCULAR DISEASE R.D. Brook. Division of Cardiovascular Medicbte, Universi~ of Michigan,
Ann Arbor; Michigan, USA Objective: To raviaw tha sciantific avidanca linking particulate mattar (PM) air pollution to an incraasad risk of cardiovascular disaasas. Methods: Litaratura raviaw Results: PM air pollution is a complax, hataroganaous mixtura of aarosols that wxy in size from savaral nanomatars (PM0.1), through fina PM <2.5 I~m (PM2.5), to coarsa PM batwaan 2.5 and 10 I~m in diamatar (PM10). Tha avidanca most strongly links PM2.5 to advarsa cardiovascular (CV) haalth affacts; howavar more racant findings also implicata ultrafina (PM0.1) PM. In tha modarn world, most PM2.5 is darivad from urban fossil fuel combustion, industry, and from mobila sourcas such as automobilas and diasal axhaust. Tha chamical composition of tha PM mixtura may play a role in datarmining tha haalth impact. Individuals with pra-axisting heart or lung disaasa and diabatas may ba at highar CV risk dua to tha affacts of PM. Epidamiological studias conductad throughout tha world have confirmad a consistant, gradad association batwaan PM axposura and incraasad risk for CV avants. Short-tarm (hours-to-days) axposura incraasas tha risk for acute (1-5 days) CV mortality by 0.31 to approximataly 1.0% par 10 i~g/m3 alavation in PM10. Tha risk for acute myocardial infarction has been shown to incraasa by as much as 48% within 2 hours (par 25 i~g/m3 incraasa in PM2.5) in Boston. Studias in Rome and Europa confirm tha association batwaan acute myocardial infaxction and also ra-infaxction with axposura to PM. Automobila sourcas of PM may ba particularly harmful, incraasing tha risk for myocardial infaxction by 2.9-fold within 1 hour. PM may also triggar stokas. Studias assassing tha long-tarm affacts of PM axposura damonstrata an even graatar affact on CV risk. Sixtaan year axposura to alavatad PM2.5 incraasas tha mortality due to CV disease (RR 1.12), ischemic heart disaasa (RRI.18), and axrhythmia/haart faJlura/caxdiac arrast (RR 1.13). Savaral machanisms have now been dascribad that may axplain tha biological pathways rasponsibla. PM axposura could play a role in atharosclarotic CV disaasa at all stagas: from promoting tha davalopmant of traditional CV risk factors (a.g. hypartansion), to diracdy facilitating tha ganasis of atharosclarosis (a.g. vascular inflammation), to triggaring acute plaqua ruptura and instigating suddan avants (a.g. vasoconstriction, anhancad thrombosis). In ganaral, tha pulmonary inhalation of PM could aYfact tha systamic vasculatura by ganarating local lung tissua oxidativa strass/inflammation with tha subsaquant spill-ovar of activatad cells and pro-inflammatory madiators; by diracdy altaring autonomic balanca through intaracting with pulmonary racaptors; and/or by diract affacts on tha vasculatura by PM or solubla constituants capabla of raaching tha circulation. PM has been shown to triggar acute arterial vasoconstriction and andothalial dysfunction, possibly as a rasult of oxidativa strass, that could chronically promota atharosclarosis and acutaly triggar ischamia. Other studias show incraasad systamic inflammation, anhancad thrombosis/coagulation, and autonomic imbalanca dua to PM inhalation. Racantly, axparimants in both animals and humans corroborata that tha chronic axposura to PM can actually promota tha ganasis of atharosclarosis itsalf. Conclusions: Both short and long-tarm axposura to PM air pollution is linkad to incraasa risk of CV disaasa. PM is capabla of both triggaring acute CV avants and promoting tha davalopmant of atharosclarosis via savaral machanistic pathways. References [1] Brook RD, Franklin B, Cascio W, at al. Air pollution and cardiovascular disaasa. A statement for haalthcara professionals from tha expert panel on population and prevention science of tha American Heart Association. Circulation 2004; 109: 2655-71.
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HOXA9 AND FLK1 E X P R E S S I O N IN CD34+ PERIPHERAL CELLS OF HYPERTENSIVE PATIENTS CORRELATES WITH THE NUMBER OF CIRCULATING E N D O T H E L I A L P R O G E N I T O R CELLS
M. Pirro, C. Manacali, F. Bagaglia, M.R. Mannaxino, G. Schillaci, E. Mannarino. InterTtal Medicbw, Angiology attd Arteriosclerosis Diseases,
Perugia, Italy Objective: HoxA9, a critical regulator of postnatal neovasculaxization and endothelial commitment during progenitor cell maturation, is essential for the expression of the endothelial-committed genes (ex. F l k l ) . We investigated whether in hypertensive patients CD34+ cells expression of HoxA9 and F l k l is impaired and if a correlation exists between the expression of these genes and the number of circulating endothelial progenitor cells. Methods: 20 patients with never-treated essential hypertension and 10 ageand sex-matched normal controls were recruited for the study. Total RNA was isolated from circulating CD34+ cells and subjected to quantitative RT-PCR for measurement of HoxA9 and F l k l expression. The number of endothelial progenitor cells was measured after PBMC isolation, staining with anti-CD34 and anti-Flkl fluorescent antibodies and flow-citometry analysis. Results: hypertensive patients had a reduced expression of HoxA9 and F l k l genes compared to normotensive subjects. In addition, the number of peripheral CD34+ cells and that of circulating endothelial progenitor cells was significantly lower in hypertensive than in normotensive subjects. Intarastingly, a direct correlation was obsarvad batwaan CD34+ cells gene axprassion of HoxA9 and F l k l , on tha ona hand, and tha numbar of andothalial proganitors, on tha other hand. Conclusions: in hypartansiva patiants, a down-regulation of paripharal CD34+ cells HoxA9 and F l k l gana axprassion may contributa to raduca tha numbar of circulating andothalial proganitor calls, thus potantially impairing postnatal naovascularization and vascular reparation.
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A S Y M M E T R I C D I M E T H Y L A R G I N I N E ( A D M A ) IS A S S O C I A T E D W I T H I N C I D E N T CARDIOVASCULAR D I S E A S E IN T H E G E N E R A L P O P U L A T I O N . T H E H O O R N STUDY
T. Taarlink, R.J. Heine, G. Nijpals, L.M. Boutar, C.D.A. Stahouwar, J.M. Dakkar. Institute For Cardiovascular Researeh, VU Universi~ Medical
Center: Amsterdam, the Netherlands Objective: Incraasad asymmatric dimathylaxginina (ADMA), an andoganous inhibitor of nitric oxide synthasa, pradicts cardiovascular disaasa (CVD) in high-risk patiant groups. Wa have prospactivaly studiad tha association batwaan A D M A and CVD in tha ganaral population. Methods: Tha Hoorn Study, a community-basad prospactiva cohort study, startad in 1989. Plasma A D M A at basalina was maasurad by HPLC in 1707 subjacts (aga 50 to 75 yaars, 158 with type 2 diabatas). Tha main outcoma maasura was tha combinad incidanca of fatal and non-fatal CVD during 10-yaax follow-up. Tha ralation batwaan A D M A and CVD was axaminad with Cox proportional hazards modals. Results: During follow-up, 389 subjacts (68 with diabatas) axpariancad a cardiovascular avant. Tha ralation batwaan A D M A and CVD was not continuous but rastrictad to tha highast quintila. After adjusting for aga, gandar and astablishad risk factors (cholastarol, HDL-cholastarol, body mass indax, renal function, hypartansion, smoking, glucosa and pravalant CVD) a high plasma concantration of A D M A fi.a. highast quintila varsus lowast four quintilas) was associatad with a hazard ratio for CVD of 1.49 (95% C.I., 1.16 to 1.90) in subjacts without diabatas and 0.48 (0.24 to 0.98) in subjacts with diabatas. In analysas rastrictad to participants without diabatas and CVD at basalina, tha hazard ratio was 1.40 (1.02 to 1.91). Conclusion: A high plasma concantration of A D M A indapandantly pradicts CVD in subjacts without type 2 diabatas. Tha invarsa ralation batwaan high A D M A and CVD in subjacts with diabatas needs confirmation in other populations.
XIV bzterTmtional Symposium on Atherosclerosis, Rome, Italy, June 18-22, 2006