Classification of Endothelial Dysfunction. Stefano Taddei Department of Internal Medicine University of Pisa, Italy

Transcription

1 Classification of Endothelial Dysfunction Stefano Taddei Department of Internal Medicine University of Pisa, Italy

2 Pathogenesis of atherosclerosis from endothelial dysfunction to clinical disease endothelial dysfunction PGI EDHF NO plaque growth stimuli-induced vasodilation (e.g, to shear stress) remodeling/ proliferation acute coronary syndrome ischemia / angina pectoris clinical manifestations

3 Vascular effects of principal endothelium-derived substances Healthy conditions CV risk factors Vasodilation Platelet aggregation VSMC migration and proliferation Monocyte adhesion Adhesion molecules expression ET1 NO EDCFs (ET-1; A-II; TXA 2 ; PGH 2 ; O 2 -) Vasoconstriction NO breakdown: Platelet aggregation VSMC migration and proliferation Monocyte adhesion Adhesion molecules expression Each effect is a different aspect of endothelial function or dysfunction

4 Endothelial Pathology Endothelial Dysfunction reduced NO availability (vascular reactivity) Endothelial Activation acquisition of flogistic activity Endothelial Injury and Repair anathomical disruption and rigeneration of endothelial cells

5 Markers and clinical significance of endothelial pathology ENDOTHELIAL DYSFUNCTION NO NO2/NO3 and other plasma nitrosylated species ADMA Evaluation of vascular reactivity ENDOTHELIAL ACTIVATION adhesion molecules: E-selectin, P-selectin, ICAM-1, VCAM-1 Regulators of thrombosis: tpa, PAI-1 ENDOTHELIAL DAMAGE vwf soluble thrombomodulin circulating endothelial cells endothelial microparticles ENDOTHELIAL REPAIR circulating endothelial progenitor cells

6 Markers and clinical significance of endothelial pathology ENDOTHELIAL DYSFUNCTION NO NO2/NO3 and other plasma nitrosylated species ADMA Evaluation of vascular reactivity ENDOTHELIAL ACTIVATION adhesion molecules: E-selectin, P-selectin, ICAM-1, VCAM-1 Regulators of thrombosis: tpa, PAI-1 ENDOTHELIAL DAMAGE vwf soluble thrombomodulin circulating endothelial cells endothelial microparticles ENDOTHELIAL REPAIR circulating endothelial progenitor cells

7 Plasma ADMA is significantly associated with all-cause mortality The Framingham Offspring study Böger RH et al Circulation 2009

8 ADMA as a prospective marker of CV disease and mortality High risk Intermediate risk Low risk general population Boger RH et al. Pharmacological Research 2009

9 Vascular Reactivity Vascular response to stimulation or inhibition of endothelial function Selectivity for vessel type and vascular district Large availability of agonists and antagonists Strong association with intermediate organ damage and clinical endpoints

10 Effect of aging on endothelium-dependent vasodilation in the forearm microcirculation Normotensive Subjects (N=43) Taddei S et al. Circulation 1995

11 Normotensive Subjects Essential Hypertensive Patients FBFD% saline L-NMMA Ouabain * p<0.05 * Control Vitamin C * * * * * 0 BRADYKININ BRADYKININ BRADYKININ µg/100 ml/min Taddei S et al Circulation 1999

12 Coronary endothelial dysfunction in hypertensive patients Role of oxidative stress Solzbach U et al, Circulation 1997

13 Maximal Achetilcholine-induced FBF increase ( D%) Association between endothelial dysfunction and atherosclerosis CORONARY ARTERIES CAROTID ARTERIES 2000 r = -.58 p< ,6 0,9 1,2 1,5 1,8 2,1 INTIMA-MEDIAL THICKNING (mm) Zeiher AM et al. Circulation 1994 Ghiadoni L et al. Hypertension 1998

14 Endothelial Function Assessed by Vascular Reactivity and Cardiac Events Multivariant analysis of hazard ratio of present studies reporting association between coronary or peripheral endothelial function and cardiovascular events Lerman A & Zeiher A Circulation 2005

15 Vascular effects of principal endothelium-derived substances Healthy conditions CV risk factors Vasodilation Platelet aggregation VSMC migration and proliferation Monocyte adhesion Adhesion molecules expression ET1 NO EDCFs (ET-1; A-II; TXA 2 ; PGH 2 ; O 2 -) Vasoconstriction NO breakdown: Platelet aggregation VSMC migration and proliferation Monocyte adhesion Adhesion molecules expression

16 t-pa balance (ng/100 ml/min) Effect of NO-synthase blockade by L-NMMA on t-pa release in normotensive subjects and essential hypertensive patients ACh induced release 1.0 Normotensive subjects Hypertensive patients 0.5 * 0 ACh ACh + L-NMMA ACh + L- NMMA Giannarelli C et al Hypertension 2007

17 tpa release ng/100ml/min Effect of bradykinin on tpa release in the presence of saline or sulfaphenazole in hypertensive patients Hypertensive Patients Saline Sulfaphenazole p<0.01 vs BDK+saline * 0 Baseline Bradykinin Giannarelli C et al Circulation 2009

18 Relaxation t-pa release Smooth muscle cells Endothelial cells NO EDHF Bradykinin

19 Markers and clinical significance of endothelial pathology ENDOTHELIAL DYSFUNCTION NO NO2/NO3 and other plasma nitrosylated species ADMA ENDOTHELIAL ACTIVATION adhesion molecules: E-selectin, P-selectin, ICAM-1, VCAM-1 regulators of thrombosis: tpa, PAI-1 ENDOTHELIAL DAMAGE vwf soluble thrombomodulin circulating endothelial cells endothelial microparticles ENDOTHELIAL REPAIR circulating endothelial progenitor cells

20 Endothelial activation represents a switch from a quiescent phenotype toward one that involves the host defense response Constans J et al Clinica Chimica Acta 2006

21 Soluble e-selectin in essential hypertension: a correlate of vascular structural changes De Caterina R et al Am J Hypertens 2001

22 Soluble adhesion molecules and prediction of coronary heart disease: a prospective study and meta-analysis The odds ratio for CHD were 1 68 (95% Cl ) for ICAM-1 and 1 27 ( ) for E-selectin, but became not significant after adjustment for some classic coronary risk factors and indicators of socioeconomic status. The measurement of adhesion molecules is unlikely to add much predictive information to that provided by more established risk factors. Malik I et al Lancet 2001

23 Markers and clinical significance of endothelial pathology ENDOTHELIAL DYSFUNCTION NO NO2/NO3 and other plasma nitrosylated species ADMA ENDOTHELIAL ACTIVATION adhesion molecules: E-selectin, P-selectin, ICAM-1, VCAM-1 Regulators of thrombosis: tpa, PAI-1 ENDOTHELIAL DAMAGE Von Willebrand Factor soluble thrombomodulin circulating endothelial cells endothelial microparticles ENDOTHELIAL REPAIR circulating endothelial progenitor cells

24 Von Willebrand Factor, Soluble P-Selectin, and Target Organ Damage in Hypertension A Substudy of the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT) * * p<0.05 * * p<0.05 * Hypertensive patients Spencer CGC et al Hypertension 2002

25 A comparison of FMD and VWF as markers of endothelial cell function in health and in hypertension A substudy of the Anglo-Scandinavian Cardiac Outcomes Trial r=0.517, p < vwf and FMD both correlated with 10-year cardiovascular risk using the Framingham equation (vwf, r=0.48, p< 0.001; FMD, r =0.624, p< 0.001). Felmeden DC et al Blood Coagulation and Fibrinolysis 2003

26 Soluble thrombomodulin Thrombomodulin (TM) is specifically expressed by endothelial cells Soluble TM can be reliably measured by ELISA Controversial clinical significance: TM is released from injured endothelial cells high levels indicate a greater extent of endothelial damage? TM plays a role as a protein C cofactor and has anticoagulant activity high levels may be protective?

27 High Soluble thrombomodulin predicts recurrence after CAD and mortality after stroke 54 patients who had survived a myocardial infarction Soluble thrombomodulin was 65+/-24 ng/ml in patients who suffered an end-point and was 49+/-19 ng/ml in patients who were free of an end-point (p=0.009). Using life tables, soluble thrombomodulin had a significant effect on survival free of an end-point (p=0.011). Blann AD et al. Eur J Haematol patients with previous brain infarction 5 years follow up Soluble thrombomodulin among the upper tertile confers risk of recurrence of 2.04 ( ), as compared to the lower tertile Olivot GM et al Stroke 2004

28 Rate ratio of incident coronary heart disease Low stm predicts CHD in healthy individuals The ARIC study < >66.3 Quintiles of soluble thrombomodulin (ng/ml) Possible explanation: In healthy people, concentrations of soluble thrombomodulin may reflect the quantity of thrombomodulin expressed on the endothelial surface. Increased expression of thrombomodulin will increase production of activated protein C, which suppresses the coagulation reaction by degrading factors Va and VIIIa. Salomaa V et al Lancet 1999

29 Endothelial Dysfunction (FMD) and Damage (CEC) in Congestive Heart Failure r=0.423, p=0.002 Chong AY et al. Circulation. 2004;110:

30 Circulating endothelial cells and prognosis in 156 patients with acute coronary syndromes Numbers of circulating endothelial cells (CECs) on admission according to diagnosis and compared with patients with stable angina and healthy control subjects. STEMI indicates ST-segment elevation myocardial infarction; NSTEMI, non-stemi; UAP, unstable angina pectoris; SA, stable angina. Kaplan-Meier cumulative 1-year event-free survival curves between more than median versus less than median values of (A) CECs at 48 hours Lee KW et al. Blood 2005;105:526 32

31 Circulating endothelial cells in hypertension and acute ischaemic stroke 29 hypertensive patients with previous stroke, 30 hypertensive patients and 30 normotensive controls Patients with an acute ischaemic stroke had significantly higher numbers of CECs/ml of blood (p<0.001) plasma vwf (p=0.008), soluble E-selectin (p=0.002) and higher SBP as compared to the other groups The number of CECs significantly correlated with soluble E-selectin (r=0.432, p<0.001) and vwf (r=0.349, p=0.001) but not with SBP (r=0.198, p=0.069) Nadar SK et al, Thromb Haemost 2005; 94:

32 Microparticles Microparticles are submicron vesicles derived from cell membranes They are shed from plasma membranes in response to cell activation, injury, and/or apoptosis Microparticles originating from platelets, endothelial cells and leukocytes have been most extensively studied Chironi NG et al, Cell Tissue Res (2009) 335:

33 Circulating microparticles (events/µl) Circulating Endothelial Microparticles Are Associated with Vascular Dysfunction in Patients with End-Stage Renal Failure Flow cytometry analysis of platelet-free plasma from 44 patients with ESRF indicated that circulating levels of Annexin V+ microparticles were increased compared with 32 healthy subjects, as were levels of microparticles derived from endothelial cells (three-fold), platelets (16.5-fold), and erythrocytes (1.6-fold). Platelet-derived MP Endothelium-derived MP Endothelium-derived MP Erythrocytes-derived MP End stage renal failure Healthy subjects Amabile N et al. J Am Soc Nephrol 16: , 2005

34 Markers and clinical significance of endothelial pathology ENDOTHELIAL DYSFUNCTION NO NO2/NO3 and other plasma nitrosylated species ADMA ENDOTHELIAL ACTIVATION adhesion molecules: E-selectin, P-selectin, ICAM-1, VCAM-1 Regulators of thrombosis: tpa, PAI-1 ENDOTHELIAL DAMAGE vwf soluble thrombomodulin circulating endothelial cells endothelial microparticles ENDOTHELIAL REPAIR circulating endothelial progenitor cells

35 Conclusions Classification of endothelial dysfunction is important to understand the pathophysiology of atherosclerotic disease and in the next future might be useful for a better determination of CV risk and the effectiveness of treatment. However, at the present time, the different aspects of endothelial dysfunctions are not related to a specifc clinical significance. Further investigation is necessary to establish the exact relationship between the different types of endothelial alterations and the development of CV disease. In addition, no large scale intervention trials are available to consider endothelial dysfunction as a target of CV treatment.