Declaration of conflict of interest

Transcription

1 Declaration of conflict of interest

2 Inhibitors of vascular calcification what have we learned from animal models Ralf Westenfeld Department of Cardiology Heinrich-Heine-University Düsseldorf

3 Do you know your calcification score?

4 Outline 1 Epidemiology of calcification 2 Calcification -a chemist s view 3 Calcification Inhibitors

5 Outline 1 Epidemiology of calcification 2 Calcification -a chemist s view 3 Calcification Inhibitors

6 Jährliche Annual Mortality Sterblichkeit [%] (%) Exzessive mortality in HD patients Dialysepatienten Hemodialysis Normalbevölkerung Controls >85 Age Alter

7 Calcification mortality predictor Okuno S, Am J Kidney Dis. 2007; patients (60 ± 12 Jahre), single Center, follow Up 60 Monate, 103 deaths 40 x 2.7 Calcified Aorta: yes no [%] x All-Cause Mortality CV Mortality

8 Atherosclerosis Inflammatory Lipid deposition ischemia-related, occlusion Mediasclerosis Non-inflammatory No lipid deposition Usually asymptomatic pseudohypertension

9 Valvular calcifications in uremia Myocardial calcifications in uremia More angiogenesis and macrophage infiltration as compared to normal controls Kajbaf S et al., AJKD 2005

10 Calcification clinical correlates [%] 40 CAC Score: > previous MI symp.angina known CAD Raggi et al., J Am Coll Cardiol 2002

11 Outline 1 Epidemiology of calcification 2 Calcification -a chemist s view 3 Calcification Inhibitors

12 Calcification chemist s view = Soft tissue and vascular calcifications: amorphous calcium phosphate or hydroxyapatite Ca 5 (PO 4 ) 3 OH Contiguglia et al. Kidney Int 1973 Schwarz et al. Nephrol Dial Transplant 2000 LeGeros Z Kardiol 2001

13 Calcification chemist s view 2.5 mm/l (= 7.8 mg/dl) inorg. phosphate (Na 2 HPO 4 ) 1.25 mm/l (= 5 mg/dl) calcium (CaCl 2 )

14 Calcification chemist s view 2.5 mm/l (= 7.8 mg/dl) inorg. phosphate (Na 2 HPO 4 ) 1.25 mm/l (= 5 mg/dl) calcium (CaCl 2 ) Both combined

15 Experimental CKD in mice Two step procedure - mild uremia d 0 42d Time Uremia ± high phosphate diet Westenfeld, Nephrol Dial Transplant; 2007

16 [mg/dl] [µg Ca/mg dry weight] Phosphate loading induces VC Design: Severe and moderate CKD was induced in DBA/2 mice and combined with high- (HP) and normal phosphate (NP) diet. Results: Calcium Content Aorta 15 Phosphate loading was indespensable to induce medial calcification, even in mice with severe CKD. Moderate CKD with HP diet provoked VC despite normal serum phosphorus levels Serum Phosphate induction of osteochondrogenic markers reduction of VSMC markers Sham Mild CKD Severe CKD El-Abbadi, Kidney Int, Epub March 2009

17 Elevated P i and VC in mild CKD Design: - n= 439 (MESA cohort) mild CKD (egfr 51 ml/min) Results: calcification coronaries thoracic aorta aortic valve mitral valve prevalence (%) % 80% 60% 40% 20% No. of calcified sites % < >4 P i [mg/dl] Higher Pi serum concentrations (in the normal range) are associated with a greater prevalence of vascular and valvular calcification Adeney, J Am Soc Nephrol, 20(2):381;2009

18 Calcification the role of serum

19 Outline 1 Epidemiology of calcification 2 Calcification -a chemist s view 3 Calcification Inhibitors

20 Activators / inhibitors of calcification CaxP i -Produkt Fetuin-A - the systemic calcification Inhibitor Matrix-Gla Protein - the local calcification inhibitor Osteoprotegerin - RANKL - ANK - BMP-7 - BMP-4 - Osterix - Sos-9 - Pyrophosphat - Alkalische Phosphatase - Kollagen Typ I - cbfa-1 - osteopontin - Transglutaminase - Magnesium - warfarin - Smad 6 - NPP 1- Leptin -

21 Fetuin-A Systemic VC inhibition hepatic synthesis serum con g/l negative acute-phase P. potent inhibitor of hydroxyapatite formation.

22 Calcification in Fet-A deficent mice Schäfer, Westenfeld,... Jahnen-Dechtent, J Clin Invest. 2003

23 Cardiovascular Survival Fetuin deficiency in HD patients Ketteler M... Westenfeld et al., Lancet. 2003

24 Von Kossa [%] Vascular calcification Fet/ApoE mice Design: - Fetuin-A / ApoE double-ko mice - mild CKD and/or High P i Diet Aorta Kalzifizierung Calcification Westenfeld R, Schäfer C et al.; JASN, 2009

25 Interaction of calcification inhibitors? mrna expression Aorta Osteopontin mrna correlates with vascular calcification Matrix Gla Protein (MGP) induction precedes calcification Westenfeld R, Schäfer C et al.; JASN, 2009

26 Matrix-gla-protein local inhibition MGP +/+ MGP -/- MGP -/- ; Hyp lethal 6weeks Murshed M et al., Genes & Dev 2005

27 Matrix-gla-protein local inhibition MGP +/+ MGP -/- MGP -/- sm22tg lethal 6weeks only local genetic rescue is effective Murshed M et al., Genes & Dev 2005

28 Matrix-gla-protein local inhibition MGP +/+ MGP -/- MGP -/- sm22tg MGP -/-; Hyp lethal 6weeks only local genetic rescue is effective hypophosphatemia rescues MGP deficiency Murshed M et al., Genes & Dev 2005

29 control control Positive area [µm 2 ] VSMC number [per µm 2 ] VC due to MGP inactivation Calcification aorta VSMC number ** *** warfarin [mg/g] K1 [mg/g] warfarin treatment [days] 100µm Aortic valve Control 28 days warfarin 49 days warfarin Peak Gradient [mmhg] 8.6 ± ± ±3.1 Aortic stiffness pulse wave velocity [m/s] 1.9 ± ± ± 0.47 Veulemanns, Westenfeld unpublished

30 Apoptosis promotes calfication Design: - SM22a-hDTR/ApoE -/- mice Chronic VSMC apoptosis i.p. diphtheria toxin injection - low-levels apoptosis (1% of VSMC cells) - accelerated plaque growth. - enhanced plaque calcification Murray, Circ Res 2008

31 In summary we have learned from animal models, that... VC is aggravated by precipitation of Ca and P i. VC is an active process involving systemic (Fetuin-A) and local (MGP) inhibitors. chronic apoptosis enhances vascular calcification. robust calcification models may serve as a valuable tool to investigate potential treatment strategies (Vitamin K, OPG, etc.)

32 V. Veulemans P. Horn T. Rassaf M. Kelm Düsseldorf V. Brandenburg W. Jahnen-Dechent J. Floege Aachen L. Schurgers E. Cranenburg S. Heidenreich KfH Aachen S. Holzmann Erkelenz C. Vermeer Maastricht M. Ketteler Coburg