ΠΑΝΕΠΙΣΤΗΜΙΟ ΙΩΑΝΝΙΝΩΝ ΔΠΜΣ Ιατρική Χημεία Μοριακή φαρμακολογία αιμοπεταλιακών υποδοχέων. Ανταγωνιστές των αιμοπεταλιακών υποδοχέων, υποκείμενοι μοριακοί μηχανισμοί και κλινική σημασία Αλέξανδρος Δ. Τσελέπης, MD, PhD Καθηγητής Βιοχημείας Κλινικής Χημείας
The Platelet
Σχηματική απεικόνιση του αιμοπεταλίου
ΠΑΡΑΓΟΝΤΕΣ ΠΗΞΗΣ-INΩΔΟΛΥΣΗΣ ΤΩΝ ΑΙΜΟΠΕΤΑΛΙΩΝ Παράγοντας Ινωδογόνο Παράγοντας V vwf Παράγοντας XI Παράγοντας XII HMWK Πρωτείνη S tpa PAI-1 Υποκυτταρική κατανομή Κυτταρική μεμβράνη, α-κοκκία α-κοκκία α-κοκκία Κυτταρική μεμβράνη Κυτοσόλιο α-κοκκία α-κοκκία α-κοκκία α-κοκκία
ΣΥΣΤΑΤΙΚΑ ΤΩΝ α-κοκκιων Αλβουμίνη β-θρομβοσφαιρίνη Κλουστερίνη Παράγων πήξης V Ινωδογόνο Φιβρονεκτίνη IgG Μουλτιμερίνη PDGF PF4 PAI-1 Θρομβοσπονδίνη Βιτρονεκτίνη vwf tpa TGF-β1 GP Ib-IX GP IV GP V α IIb β 3 PECAM-1 P-σελεκτίνη
ΣΥΣΤΑΤΙΚΑ ΤΩΝ ΠΥΚΝΩΝ ΚΟΚΚΙΩΝ ATP, GTP ADP, GDP Σεροτονίνη Ca 2+, Mg 2+
ΣΥΣΤΑΤΙΚΑ ΤΩΝ ΛΥΣΟΣΩΜΑΤΙΩΝ β-γλυκουρονιδάση β-γαλακτοσιδάση Ν-ακετυλογλυκοζαμινιδάση β-εξοζαμινιδάση Ενδογλυκοσιδάση β-γλυκεροφωσφατάση Καθεψίνες Ελαστάση Κολλαγονάση
INTEΓΚΡΙΝΕΣ-ΥΠΟΔΟΧΕΙΣ ΠΡΟΣΚΟΛΛΗΣΗΣ ΤΩΝ ΑΙΜΟΠΕΤΑΛΙΩΝ Υποδοχέας Αριθμός Προσδέτης α 2 β 1 (GP Ia-IIa) α 5 β 1 (GP Ic-IΙa) α 6 β 1 (GP Ic*-IΙa) α IIb β 3 (GP IIb-IΙIa) α ν β 3 1.000 1.000 1.000 40.000 80.000 500 Κολλαγόνο Φιβρονεκτίνη Λαμινίνη Ινωδογόνο, vwf, Φιβρονεκτίνη, Βιτρονεκτίνη Ινωδογόνο, vwf, Φιβρονεκτίνη, TSP Βιτρονεκτίνη
ΥΠΟΔΟΧΕΙΣ ΠΡΟΣΚΟΛΛΗΣΗΣ ΤΩΝ ΑΙΜΟΠΕΤΑΛΙΩΝ Υποδοχέας Αριθμός Προσδέτης GP Ib-IX-V GP IV GP VI PECAM-1 P-σελεκτίνη 20.000-30.000 25.000-5.000 10.000 Έκκριση α-κοκκίων vwf Κολλαγόνο, TSP Κολλαγόνο PECAM-1 PSGL-1, Sle a, SLe x
ΠΑΘΟΦΥΣΙΟΛΟΓΙΚΟΣ ΡΟΛΟΣ ΤΩΝ ΑΙΜΟΠΕΤΑΛΙΩΝ Θρόμβωση / Αιμόσταση Φλεγμονή Αθηρωμάτωση Αλλεργία Μεταστάσεις όγκων Οξειδωτικό στρες
Platelet Aggregation 0.5 μμ ADP 1.0 μμ ADP 2.5 μμ ADP 5.0 μμ ADP 1 min 10 μμ ADP Χρόνος, min
Platelet in Initiation of Thrombus Formation Fibrinogen Gp IIb/IIIa complex Platelet Fibrinogen Von Willebrand factor
Platelet-dependent thrombus formation at a ruptured atherosclerotic plaque Gawaz M, et al. Cardiovasc Res 2004: 61:498 511
Platelet aggregation and adhesion
Mechanism of PMPs production Freyssinet JM. J. Thromb. Haemost. 2003;1:1655-1662 VanWijk MJ et al. Cardiovasc. Res. 2003;59:277-287
Functions attributed to PMPs VanWijk MJ et al. Cardiovasc. Res. 2003;59:277-287
Role of scd40l in Atherogenesis
Sites of action of antiplatelet agents Kalantzi KI, et al. Expert Rev Clin Pharmacol. 2012;5:319-336
Relative effects of antiplatelet regimens versus placebo, aspirin, and clopidogrel in reducing the risk of stroke, MI, or vascular death Hankey GJ, et al. Lancet Neurol 2010; 9: 273 84
AA metabolism and the effect of COX-1 inhibitors Kalantzi KI, et al. Expert Rev Clin Pharmacol. 2012;5:319-336
Aspirin as α cornerstone therapy for CVD C O O H O C O C H 3 C O O H O H ACTIVE A C E T Y L S A L I C Y L I C A C I D INACTIVE S A L I C Y L I C A C I D Mc Neely W, Goa KL. Triflusal. Drugs 1998 Jun; 55(6):823-33
COX-1 Inhibition With Aspirin Schroeder WS, et al. J Thr Thrombol. 2006; 22:139-150 Patrono C, et al. Nature. 2007; 4:42-50
Triflusal C O O H O C O C H 3 C O O H O H C F 3 ACTIVE C F 3 ACTIVE T R I F L U S A L H T B C O O H O C O C H 3 C O O H O H ACTIVE INACTIVE A C E T Y L S A L I C Y L I C A C I D S A L I C Y L I C A C I D Mc Neely W, Goa KL. Triflusal. Drugs 1998 Jun; 55(6):823-33
Mode of Action TRIFLUSAL DIPYRIDAMOLE TRIFLUSAL ASPIRIN ASPIRIN CILOSTAZOL Vascular Cyclooxygenase Adenylate cyclase Arachidonic acid PGI 2 ATP camp camp- Phosphodiesterase 5'-AMP Arachidonic acid Platelet Cyclooxygenase Inhibition of TxA 2 Synthesis Ca ++ Block Phospholipase A 2 activation Ca-dependent platelet reaction PLATELET AGGREGATION INHIBITION
Cilostazol, Dipyridamol
Η σημασία του αιμοπεταλιακού υποδοχέα P2Y12 στην ενεργοποίηση των αιμοπεταλίων και οι σημαντικότεροι αναστολείς του
The P2Y 12 receptor and platelet activation Adenosine diphosphate (ADP) is secreted by activated platelets (Davi 2007; Meadows 2007) ADP binding to the P2Y 12 receptor is important for sustaining platelet activation and aggregation (Dorsam 2004; Davi 2007) G-protein-coupled receptor on platelet surface [Dorsam 2004] Potentiates further ADP secretion Recruits additional platelets Facilitates platelet adhesion Davi GD, et al. N Engl J Med. 2007;357:2482-2494; Meadows TA, et al. Circ Res. 2007;100:1261-1275; Dorsam RT, et al. J Clin Invest. 2004;113:340-345.
Pathways Activated Following Stimulation of P2Y12 by ADP VASP: Vasodilator-Stimulated Phosphoprotein Kleiman NS, et al. JACC. 2008; 51: 1412-1414
Clopidogrel Prasugrel Husted S, et al. Cardiov Therap 27 (2009) 259 274
Cangrelor Inhibition of P2Y 12 receptor Direct-acting Competitive Reversible Plasma half-life: 3 to 5 min Platelet function is restored within 1h after cessation of the infusion
Θειενοπυριδίνες Μη αντιστρεπτοί αναστολείς του Υποδοχέα του ADP P2Y12 O OCH 3 N N S Cl Ticlopidine (1 st generation) S Cl Clopidogrel (2 nd generation) Prasugrel (CS-747, LY640315) O O N CH 3 O S F
Mechanism of action of thienopyridines Variable proportion of prodrug metabolized to active drug by cytochrome P450 Hydrolysis by esterases Irreversible, covalent binding to P2Y 12 receptor Active drug ADP Inactive metabolites elimination by urine/feces Platelets require replacement for return to activity Meadows TA, et al. Circ Res. 2007;100(9):1261-1275; Beitelshees A, et al. Arterioscler Thromb Vasc Biol. 2006;26:1681-1683; Wiviott S, et al. Circulation. 2010; 122: 394-403; Cattaneo M. Eur Heart J. 2008;10(Suppl I):I33-I3; Ibanez B, et al. Eur Heart J. 2006:8:G.3
Κλοπιδογρέλη Μέγιστη ανασταλτική δράση 75 mg 24 h 300 mg 600 mg ή 900 mg 6 h 2 h
P2Y 12 ADP receptor inhibition by clopidogrel Κλοπιδογρέλη (προφάρμακο) S Μη αντιστρεπτή (ομοιοπολική) σύνδεση της κλοπιδογρέλης στον υποδοχέα P2Y12 Κλοπιδογρέλη (ενεργός μεταβολίτης)
Clopidogrel resistance CYP2C19*1/*2 CYP2C19*1/*1 Good metabolizer Intermediate metabolizer Poor metabolizer
Kaplan-Meier analysis for the cumulative incidence of stent Thrombosis and for the composite of death or stent thrombosis Sibbing D, et al. J Am Coll Cardiol 2009;53:849 56
Patient classification by CYP2C19 genotype Ahmad T, et al. Nat. Rev. Cardiol. 8, 560 571 (2011)
Genetic Effects on Pharmacokinetic and Pharmacodynamic Responses to Clopidogrel Επίπεδα ενεργού μεταβολίτη Επίδραση στα αιμοπετάλια Mega JL, et al. N Engl J Med 2009;360:354-62
Association between the CYP2C19*2 Reduced-Function Allele and the Primary Efficacy Outcome or Stent Thrombosis in Subjects Receiving Clopidogrel Mega JL, et al. N Engl J Med 2009;360:354-62
Active Metabolite Concentration (ng/ml; mean ± SD) Active Metabolite Plasma Concentrations After the Loading Dose 800 600 Clopidogrel 600 mg LD Clopidogrel 300 mg LD 400 Prasugrel 60 mg LD 200 0 0 1 2 3 4 Time (hours) SD=Standard deviation; LD=Loading dose Winters K, et al. Eur Heart J. 2007;28:218
IPA % (20 µm ADP) Inhibition of Platelet Aggregation After Loading Dose in Patients With Elective PCI 100 80 *** *** *** Prasugrel 60 mg 60 *** 40 Clopidogrel 600 mg 20 ***p<0.0001 Prasugrel vs. Clopidogrel 0 0.5 2 4 6 8 12 16 20 24 IPA=inhibition of platelet aggregation; PCI=Percutaneous coronary intervention Hours Wiviott SD et al. Circulation 2007;116(25):2923-2932
End Point (%) 15 10 TRITON TIMI-38 Balance of Efficacy and Safety CV Death/MI/Stroke Clopidogrel Prasugrel 12.1 9.9 138 events HR 0.81 (0.73-0.90) P=0.0004 NNT=46 5 0 Wiviott SD et al. N Engl J Med. 2007;357:2001-2015. TIMI Major Non-CABG Bleeds 0 30 60 90 180 270 360 450 Days Prasugrel Clopidogrel 2.4 1.8 35 events HR 1.32 (1.03-1.68) P=0.03 NNH=167 HR = hazard ratio; NNT = number needed to treat; NNH = number needed to harm
Αντιστρεπτοί Αναστολείς του Υποδοχέα του ADP P2Y12 Ticagrelor (AZD 6140) HO HO O OH N N N S N N H N F F Ticagrelor is a cyclo-pentyl-triazolo-pyrimidine (CPTP)
Ticagrelor Deepak L. Bhatt DL, et al. Nature Reviews Cardiology, 2009
Ticagrelor P2Y 12 receptor binding Ticagrelor is highly selective for the P2Y 12 receptor, compared with its effect at other P2 receptors (van Giezen 2008) Unlike thienopyridines ticagrelor does not interfere with ADP binding (van Giezen 2008) Ticagrelor prevents ADP- mediated P2Y 12 receptor activation (van Giezen 2008) Upon discontinuation, ticagrelor has a predictable and reliable offset reflecting the gradual fall in plasma concentration (Husted 2006; Gurbel 2009; van Giezen 2008) Platelet activity returns as ticagrelor is eliminated (van Giezen 2008) van Giezen JJJ. Eur Heart J. 2008;10 (Suppl D):D23-D29; Husted S, et al. Eur Heart J. 2006;27:1038-1047; Gurbel PA, et al. Circulation. 2009;120:2577-2585.
Husted S, et al. Cardiov Therap 27 (2009) 259 274
Inhibition of platelet reactivity Gurbel PA, et al. Circulation. 2009;120:2577-2585. Gurbel PA, et al. Circulation 2010;121;1188-1199
The RESPOND Study Inhibition of platelet aggregation in response to ADP in clopidogrel-responsive patients Before and after crossover Patients maintained on constant therapy Gurbel PA, et al. Circulation 2010;121;1188-1199
The RESPOND Study Inhibition of platelet aggregation to ADP in clopidogrel-nonresponsive patients Gurbel PA, et al. Circulation 2010;121;1188-1199
Ticagrelor proposed metabolic route
Cumulative Incidence (%) PLATO: Primary Efficacy Analysis Cardiovascular Death, MI, or Stroke N at risk Ticagrelor 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Clopidogrel HR, 0.84 (95% CI, 0.77-0.92) P<0.001 0 60 120 180 240 300 360 9,333 9,291 8,628 8,521 8,460 8,362 8,219 8 7 6 5 4 3 2 1 0 Days After Randomization 6,743 8,124 6,650 Clopidogrel 5.9 22% Death Ticagrelor 4.5 5,161 5,096 6.9 16% 5.8 Nonfatal MI 4,147 4,047 11.7 9.8 CI=confidence interval; HR=hazard ratio; MI=myocardial infarction This information concerns a use that has not been approved by the US Food and Drug Administration. Wallentin L et al. N Engl J Med. 2009;361:1045-1057.
Protease Activated Receptors Shah R, et al. Am Heart J. 2009;157:253-62
Αιμοπεταλιακοί υποδοχείς της θρομβίνης Protease-activated receptor (PAR)1 ( υψηλής συγγένειας υποδοχέας) PAR4 ( χαμηλής συγγένειας υποδοχέας)
Η θρομβίνη μετατρέπει το Ινωδογόνο σε ινώδες και ενεργοποιεί τα αιμοπετάλια Fibrinogen Fibrin Thrombin Resting platelets Activated platelets Θρόμβος
Proteolytic Activation of PAR-1 by Thrombin Extracellular cleavage Cleavage site site Hirudin-like binding site Tethered ligand SFLLRN Intracellular
Πρωτεολυτική ενεργοποίηση του PAR1 Σχάση με τη δράση της θρομβίνης = Προσδέτης (SFLLRN) G Landis, R.C., et al. Ann Thorac Surg 2001;72:2169-75 (Coughlin, S.R., et al. J Throm Hemost 2005;3:1800-14) Ενεργοποίηση
Intracellular Signaling induced by PAR-1 Angiolillo DJ, et al. Eur Heart J 2009
How to Shut off a Permanently Activated Receptor? Internalize the Receptor G Ishii K, et al. J Biol Chem 1993;268:9780 Ca 2+ Internalisation and desensitization By a phosphorylation-dependent mechanism
PAR-1 Antagonist SPRI A PAR-1 antagonist should block tethered ligand mechanism Thrombin LDPR SFLLRNP LDPR NRLLFS Antagonist X Signal 66
PAR-1 antagonists X Direct Thrombin Inhibitors Dabigatran Bivalirudin Angiolillo DJ, et al. Eur Heart J 2009
Vorapaxar
Vorapaxar Cheng Z, et al. Nature; 2012: 492:387-392 Leonardi S, et al. Curr Cardiol Rep; 2012: 14:32 39
P450-mediated Vorapaxar Metabolism Vorapaxar (SCH 530348) Mono-oxy metabolites M20 M20a/M22/M23/M24 M20 Active M19 Inactive Ghosal A, et al. Drug Metab Disp. 2011; 39: 30 38
Vorapaxar in the Secondary Prevention of Atherothrombotic Events Morrow DA, et al. N Engl J Med 2012; 366:1404-1413
Study Design In January 2011, Data Safety Monitoring Board suspended study drug in patients with a history of stroke (before or after randomization) due to an excess of intracranial haemorrhage David A. Morrow DA, et al. N Engl J Med 2012; 366:1404-1413
Kaplan Meier Rates CV Events Bleeding Morrow DA, et al. NEJM. 2012; 366:1404-1413
Conclusions Inhibition of PAR-1 with vorapaxar reduced the risk of CV death or ischemic events in patients with stable atherosclerosis who were receiving standard therapy However, it increased the risk of moderate or severe bleeding, including intracranial hemorrhage Morrow DA, et al. N Engl J Med 2012; 366:1404-1413
Stable patients with previous MI CV Events Bleeding Scirica ΒΜ, et al. Lancet. 2012; 380: 1317 24
Vorapaxar in Patients With PAD
Kaplan-Meier rates for the composite of CV Death, MI or Stroke Bonaca MP, et al. Circulation. 2013;127:1522-1529.
Kaplan-Meier Hospitalization for limb ischemia Kaplan-Meier Peripheral revascularization Bonaca MP, et al. Circulation. 2013;127:1522-1529.
Kaplan-Meier Urgent hospitalization for vascular cause of an ischemic nature Bonaca MP, et al. Circulation. 2013;127:1522-1529.
PAD Subgroup Analysis Conclusions Vorapaxar did not reduce the risk of CV death, MI, or Stroke in patients with PAD Vorapaxar significantly reduced acute limb ischemia and peripheral revascularization The beneficial effects of Vorapaxar on limb vascular events were accompanied by an increased risk of bleeding Whellan DJ, et al. JACC 2014; In press