Modificazioni età-correlate del signaling β-adrenergico e basi molecolari dell'utilizzo dei β-bloccanti

Transcription

1 L Italia? Non è un paese per vecchi 53 Congresso Nazionale Società Italiana di Gerontologia e Geriatria Firenze, Novembre 2008 Modificazioni età-correlate del signaling β-adrenergico e basi molecolari dell'utilizzo dei β-bloccanti Dario Leosco Cattedra di Geriatria Università degli Studi di Napoli Federico II

2 Physiologic conditions extracellular β-ar β G s α s α γ AC intracellular ATP camp + PKA RDIOMYOCYTE contractility

3 RDIOMYOCYTE extracellular intracellular AC β-ar G s α β γ PKA ATP camp Heart Failure PI3K PI3K P GRK2 contractility

4 Heart Failure P GRK2 β-ar Cardiomyocyte Extracellular Cytosol GRK2 induces β-ar INTERNALIZATION β-ar downregulation and desensitization occur also with Aging

5 Age-associated reductions of cardiac myocyte β 1 AR and β 2 AR adrenergic responses in rats Contraction Amplitude (% C) Contraction Amplitude (% C) NE concentration (M) Zinterol concentration (M) fmol/mg membrane protein p< mo 24 mo β 1 AR β 2 AR Xiao RP, Lakatta EG, Koch WJ et al. J ClinInvest1998

6 β-ar function changes with age of subject in myocytes from non failing human ventricle Davies CH, Ferrara N, Harding SE. Cardiovasc Res, 1996

7 β-adrenergic Receptor desensitization The role of GRK2 (β-ark1)

8 The β-adrenergic Receptor Kinase (βark1 or GRK2) Ubiquitously expressed member of the GRK family. Highest expressed GRK in the heart. Up-regulated (heart and blood vessels) in several cardiovascular disorders including heart failure and hypertension. Basic science research allowed for a way to inhibit the activity of this enzyme (preventing membrane translocation - βarkct).

9 β 1 -AR blockade enhances contractility reserve of the aged heart via restoring cardiac β-ar signaling Young Old + β 1 AR blockade Old + Exercise Old fmol/mg β-ars density * pmol/mg/min camp production * * Old Young Old+β 1 block Old Young Old+β 1 block Old Young Old+β 1 Block GRK2 Actin Leosco D et al. Am J Physiol 2007

10 β-ar blockade reduces cardiac GRK2 (β-ark1) levels in normal hearts Iaccarino G, Lefkowitz RJ and Walter J. Koch. Circulation 1998

11 Targeting GRK2 (β-ark1) dramatically increases survival in animal models of heart failure Harding et al. PNAS 2001

12 Cardiac GRK2 normalization via β 1 AR blockade and AAV6-βARKct Gene Therapy Improves Cardiac Function in Heart Failure Cardiac GRK2 LV prior to infection LV post-infection LV Ejection Fraction Giuseppe Rengo and Walter J. Koch. Circulation 2008

13 Cardiac GRK2 normalization via β 1 AR blockade and AAV6-βARKct gene therapy normalizes the neurohormonal axis in heart failure Giuseppe Rengo and Walter J. Koch. Circulation 2008

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15 Lymperopoulos A, Rengo G, Koch WJ. Nature Medicine 2007

16 Inhibition of adrenal GRK2 activity leads to reduction of circulating cathecolamines Lymperopoulos A, Rengo G, Koch WJ. Nature Medicine 2007

17 Inhibition of adrenal GRK2 activity leads to improved function of the failing heart. Lymperopoulos A, Rengo G, Koch WJ. Nature Medicine 2007

18 Pathophysiologic role of GRK2 and the therapeutic potential of its inhibition in heart failure.

19 Novel pathophysiologic implications of β-blocker therapy in heart failure Potential action of β-blockers of third generation (carvedilol, nebivolol) on regulating cathecolamines secretion from the adrenal gland Kajiwara K et al. J Pharmacol Exp Ther 2002

20 GRK2 as a Novel Biomarker of Heart Failure in Humans

21 Elevated myocardial and lymphocyte GRK2 expression and activity in human heart failure GRK2 Lymphocytes pt. 37 pt.53 Right Atria pt. 37 pt.53 Right Appendages GRK2 (O.D.) y = x R 2 = , p< Lymphocytes GRK2 (O.D.) Lymphocyte GRK2 activity (fmol pi/mg/min) 30 * >45% <45% Ejection Fraction (%) Iaccarino G, Leosco D, Koch WJ. Eur Heart J 2005

22 Different effects of β-blockers on lymphocyte GRK2 levels in pts with heart failure Lymphocyte GRK2 GRK2 (D.U.) Prior Post PriorPost PriorPost PriorPost Lymphocyte GRK2 GRK2 (D.U.) D.U. (300 ug IP) 9000 GRK p< 0.01 Prior Post β-blocker β-blocker 30 VO2 max (ml/kg/min) p= NS Prior β-blocker Post β-blocker Prior Post PriorPost PriorPost PriorPost p= NS Prior Post β-blocker β-blocker p= NS Prior β-blocker Post β-blocker Proportion alive Kaplan Meyer (adjusted) Responder Non Responder P< 0.01 (Log Rank Test) Months Unpublished data

23 The Role of β-adrenergic Receptor Dysregulation on Age-associated Endothelial Dysfunction

24 Endothelium dependent β-ar vasorelaxation is impaired in aged and hypertensive rats as well Fold of 10-6 M PE Aging Endothelium independent vasorelaxation Nitroprusside Log M old young Fold of 10 M PE Hypertension Endothelium independent vasorelaxation Nitroprusside Log M 1.2 β-ar vasorelaxation β-ar vasorelaxation Fold of 10-6 M PE 0.8 young Isoproterenol Log M old * Fold of 10 M PE Hypertensive Isoproterenol Log M Normotensive Leosco D et al. Am J Physiol, 2003 Iaccarino G et al. Circulation, 2002

25 Endothelial GRK2 activity is increased with aging and hypertension Aging Hypertension 20 Beta Binding Normotensive Normotensive Hypertensive Hypertensive 10 fmol/mg 0 * Young Old GRK2 GRK Young Old Old GRK2 Activity * Arbitrary Units Arbitrary Units Young Normotensive Young Hypertensive Young Old Leosco D et al. Am J Physiol 2003 Gros R et al. J Clin Invest 1997

26 Mixed endothelial β 3 -adrenoceptor agonist and α1-adrenoceptor antagonist properties of nebivolol Rozec B et al. British J Pharmacol 2006

27 Nebivolol induces endothelial β 2 -adrenergic receptor mediated nitric oxide production Nitric oxide production Cytosolic free Ca 2+ concentration Baseline Nebivolol Salbutamol Nebivolol Nebivolol + Butoxamine Baseline Nebivolol + Butoxamine Broeders MA et al. Circulation 2000

28 The Role of β-adrenergic Receptor Dysregulation on Age and Heart Failure-related Impairment of Angiogenesis

29 Age-related impairment of angiogenesis in hindlimb ischemia Old Sedentary Old Exercised P< 0.01 Capillary to fiber 0,7 0,6 0,5 0,4 0,3 0,2 0,1 P< Old SED Old EX Young SED Young EX Young Sedentary Young Exercised Leosco D et al. J Gerontol A Biol Sci, 2007

30 Aging induces downregulation of VEGF angiogenic signaling cascade in hearts Iemitsu M et al. Am J Physiol 2006

31 Angiogenesis impairment in the post-ischemic HF HF Sedentary HF Exercised Total capillary density (capillare/mm2) Capillaries Arteriolar Lenght density (mm/mm3) Arterioles Leosco D et al. Cardiovascular Research 2008

32 β 1 -AR selective blockade improves angiogenesis in the post-ischemic failing heart HF untreated 1,2 Septum 1 Border area HF β 1 -AR blockade Capillaries/mµ 2 0,8 0,6 0,4 * 0,2 0 HF HF Untreated β 1 AR block Sham Operated Zincarelli C, Rengo G, and Leosco D et al. AHA Scientific Sessions 2008

33 β 1 -AR selective blockade improves β 1 -AR pathway and LV remodelling in the post-ischemic HF pmol/mg of membrane protein HF Untreat β-ars density * HF β 1 -AR block Sham Operated pmol/mg/min c-amp production HF Untreat * HF β 1 -AR block Sham Operated A.U 1,6 1,4 1,2 1 0,8 0,6 0,4 0,2 0 HF Untreat Cardiac GRK2 * HF β 1 -AR block Sham Operated SHAM HF untreated HF β1-ar blockade 70 LV FS% SHAM HF * HF β 1 2-AR block Zincarelli C, Rengo G, and Leosco D et al. AHA Scientific Sessions 2008

34 Selective β 1 AR blockade activates VEGF/Akt angiogenic pathway in HF HF Ctrl HF β 1 -AR block HF Ctrl HF β 1 -AR block HF Ctrl HF β 1 -AR block pakt takt penos enos VEGF GAPDH p-akt/t-akt 1 0,5 0 * p-enos/enos 1,4 0,7 0 * VEGF/GAPDH 0,4 0,2 0 * HF Ctrl HF β 1 -AR block HF Ctrl HF β 1 -AR block HF Ctrl HF β 1 -AR block Zincarelli C, Rengo G, and Leosco D et al. AHA Scientific Sessions 2008

35 Shyngosine-1-Phosphate receptors (S1P1) Member of the superfamily of G-protein coupled receptors (such as β-adrenergic receptors) Essential for vasculogenesis Highly expressed in the heart Regulated by GRK2

36 GRK2 overexpression induces β-ar internalization and S1P1 receptors degradation in human coronary arteries endothelial cells β-ar S1P1r Basal Isoproterenol + GRK2 overexpression Basal Isoproterenol + GRK2 overexpression Data in progress

37 Heart Failure P GRK2 P GRK2 β-ar S1P1 contractility vasodilation angiogenesis Cardiomyocytes and Endothelial Cells Extracellular Cytosol

38 Conclusions Cardiac and vascular β-adrenergic receptor dysfunction represent a common finding of aging These abnormalities resemble those observed in heart failure and hypertension β-ar blockade has been shown to reverse receptorial and post-receptorial abnormalities of β-ar signaling

39 ß-adrenergic blockers Old and Novel Mechanisms of action Sympathetic activation HR Myocardial ischemia Blood pressure Arrhythmias Oxidative stress, proliferation, Apoptotis β-ar density and function ( The paradox ) Endothelium-mediated vasodilation Angiogenesis

40 Conclusions Cardiac and vascular β-adrenergic receptor dysfunction represent a common finding of aging These abnormalities resemble those observed in heart failure and hypertension β-ar blockade has been shown to reverse receptorial and post-receptorial abnormalities of β-ar signaling Other issues have to be considered for elderly pts with cardiovascular diseases

41 New Concept G Protein Coupled Receptor Dimerization AII NE Angiotensin Receptor β Adrenergic Receptor PIP2 IP3 ATP camp DAG

42 β-blockers Inhibit Ang II Stimulated Myocyte Contractility AII Gαq Myocyte contractility Barki-Harrington et al. Circulation 2003

43 Valsartan Uncouples Agonist-Stimulated βars and Acts Like a β-blocker In Vivo Val Gαs Barki-Harrington et al. Circulation 2003

44 Cattedra di Geriatria Università di Napoli Federico II Fondazione S. Maugeri Istituto di Telese/Campoli IRCCS The Lab Precious coworkers Franco Rengo Pasquale Abete Gianluca Testa Giuseppe Rengo Carmela Zincarelli David Della Morte Luca Golino Francesca Fortunato Daniela Femminella Elena Avallone Walter J Koch Howard Rockman Guido Iaccarino Philadelphia Durham Napoli