CKD in individuals with CKD Sylvia E. Rosas, MD, MSCE University of Pennsylvania Philadelphia VA Medical Center 3/19/2011

Objectives Brief overview of pathophysiology of CKD.

All-cause Mortality and CV Events According to Estimated GFR Go, et al All-cause Mortality and CV Events According to Estimated GFR Go, et al. NEJM 2004

CKD is prevalent in CVD 46% 43% Patients With CKD (%) 33% 23% CAD, N=431 AMI, N=14,527 CHF, N=6800 CAD CrCl ≤60 mL/min AMI GFR <60 mL/min CHF GFR ≤60 mL/min CVA GFR ≤60 mL/min Ix, et al., 2003; Anavekar, et al., 2004; Shlipak, et al., 2004, McClellan et al, 2006.

Cause of death with graft function (DWGF) among renal transplant recipients 1988-1997 Ojo, KI 2000

Mean Coronary Calcium Score Dialysis Patients have higher Coronary Calcification Score compared to CAD patients 2500 CAD-no ESRD 2000 Dialysis 1500 Mean Coronary Calcium Score 1000 Coronary calcification is much more marked in dialysis patients than in either patients with coronary artery disease (not on dialysis) or the general population. 500 28-39 40-49 50-59 60-69 Age (years) Adapted from Braun J et al. Am J Kid Dis. 1996;27:394-401.

The people to test are those at greatest risk Diabetes mellitus Hypertension Cardiovascular disease Family members of patients with ESRD Note on pediatric patients: CKD may start with childhood obesity No recommendations for routine testing

Pathological abnormalities; or Definition of CKD Kidney damage for > 3 mo, as defined by structural or functional abnormalities of the kidney, with or w/o decreased GFR, manifest by either Pathological abnormalities; or Markers of kidney damage, including abnormalities in the composition of the blood or urine, or abnormalities in imaging tests GFR < 60 ml/min/1.73m2 for > 3 mo, with or w/o kidney damage

Vascular Calcification Inductive vs. inhibitory process Inductive process Inhibitory process Pyrophosphate MGP, Osteopontin and osteoprotegerin Fetuin (a) Smad 6 BMP2 Cbfa1 Phos, PTH and Vitamin D

Stages of Chronic Kidney Disease (CKD)1 Description GFR (ml/min/1.73m2) Stage 1(National Kidney Foundation: K/DOQI Clinical Practice Guidelines for Chronic Kidney Disease: Evaluation, Classification, and Stratification. Am J Kidney Dis 39[Suppl 1]: S1-S266, 2002)

Major mechanisms of vascular calcification Major mechanisms of vascular calcification. Six different mechanisms that have been proposed to regulate the initiation or progression of vascular calcification are illustrated, along with key molecular mediators where known. The extent to which each of these mechanisms plays a role in vascular calcification in various disease states, including hyperphosphatemia and ESRD, is currently unknown. cMGP; gamma carboxylated matrix gla protein, pOPN; phosphorylated osteopontin. Giachelli, KI 2009

Ca load in the vessel wall is high in patients on dialysis Calcium accumulation in the vessel wall begins predialysis Figure 1. Quantification of Ca load in the vessel wall. (A) Dialysis vessels had a significantly higher Ca load compared with predialysis or normal vessels (P0.0001, ANOVA). (B) von Kossa staining demonstrated the absence of calcification in controls, whereas dialysis vessel showed speckled calcification (arrows) in the media and along the internal elastic lamina. M indicates media; Ad, adventitia; and Ca, calcium. Medium-sized muscular arteries routinely removed at omentectomy during a peritoneal dialysis catheter insertion or at renal transplantation in 34 patients with CKD were compared with mesenteric arteries removed at planned intra-abdominal surgery in 6 disease free, age-matched controls. Shroff et al . Dialysis Induces Apoptosis and Vascular Calcification. Circulation. 2008;118;1748-1757.

Dialysis leads to VSMC apoptosis Shroff et al . Circulation 2008 Figure 3. Cell number and apoptosis in vessels. (A)VSMC nuclei per unit area of vessel were counted on a hematoxylin-eosin stained sample to determine the number of VSMCs in different vessel types. There was no reduction in the number of VSMCs in predialysis compared with control vessels, but cell numbers were significantly reduced in dialysis vessels. (B) There was no increase in the number of apoptotic cells in predialysis as compared with normal vessels, but dialysis vessels showed significantly more apoptosis. (C) Staining for smooth muscle cell actin (top) was reduced, as was cell number in dialysis vessels compared with controls. Arrows indicate areas of cell loss in the dialysis vessel. TUNEL staining (middle) was present in dialysis vessels but absent in controls. Von Kossa staining (bottom) showed that areas of medial calcification in dialysis vessels localized to regions that were also TUNEL-positive in adjacent sections. No TUNEL positivity or calcification were observed in control vessels. VSMC indicates vascular smooth muscle cells; M, media; Ad, adventitia; -SM actin, smooth muscle cell actin; and TUNEL, terminal deoxynucleotidyl transferase mediated dUTP nick end abeling. Figure 5. Deposition of calcification inhibitors.(A) Dialysis vessels showed maximum fetuin-A positivity as compared with predialysis or normal vessels (P0.03). (B) Dialysis vessels had more Glu compared with Gla MGP: Gla/ Glu0.40.1 compared with predialysis (1.020.1) or normal (1.50.2) vessels (P0.02). (C) Immunohistochemistry for fetuin-A (top) confirmed significantly greater fetuin-A positivity in dialysis as compared with predialysis or normal vessels. Immunohistochemistry for Gla and Glu MGP (middle and bottom) showed increased amounts of Glu compared with Gla-MGP in dialysis, whereas control vessels had predominantly Gla-MGP. Gla indicates carboxylated; Glu, undercarboxylated; MGP, matrix Gla-protein; M, media; and Ad, adventitia.

Dialysis leads to VSMC apoptosis Shroff et al . Circulation 2008 heteropycnotic nuclei Cytoplasmic vacuoles and matrix vesicles Normal vesicular debris TEM showed (a) a normal contractile VSMC showing a normal nucleus with heterochromatic areas localized predominantly around the nuclear envelope. The euchromatin is interspersed with heterochromatin in the deeper regions of the nucleus. Arrowheads indicate dense bodies indicative of a contractile cell. (b) Interspersed with normal VSMCs were contractile cells with evidence of damage showing heteropycnotic nuclei (large arrow), with highly increased electron density of heterochromatin and much less euchromatin. Cytoplasmic vacuoles and matrix vesicles were deposited in the extracellular matrix adjacent to the plasma membrane. Boxed area is enlarged to show vesicles. (c) Many cells had undergone cell death leaving cellular debris, including vesicular debris (boxed area enlarged). (d) In some areas, vesicles stained with high contrast, indicating the presence of mineral (arrow). (e) The origin of vesicles from budding of the plasma membrane is shown (arrow). Bar1 m. M indicates media; Ad, adventitia; TEM, transmission electron microscopy.

Risk Factors for Vascular Calcification in CKD Intima Media Dyslipidemia √ Advanced age HTN Reciprocal Male Smoking Diabetes Inflammation √ (local) √ (systemic) Goodman et al, AJKD 2004

Risk Factors for Vascular Calcification in CKD Intima Media Reduced GFR √ Hypercalcemia Positive Ca balance Hyperphosphatemia PTH abnormalities Vitamin D administration Duration of treatment with dialysis Goodman et al, AJKD 2004

Electron Beam Tomography

EBCT Coronary Calcium Scoring Area = 15 mm2 Peak CT = 450 Score = 15 x 4 = 60 Area = 8 mm2 Peak CT = 290 Score = 8 x 2 = 16 Total Score = S Hn x-factor (Agatston Scoring) 130-199 1 200-299 2 300-399 3 >400 4

Types of Vascular Calcification Atherosclerosis Intimal Calcification Medial Calcification or Mönckeberg’s sclerosis

Association between CRP and WBC quintiles and coronary calcification Roe, Rosas, Atherosclerosis, 2010

Roe, Rosas, Atherosclerosis, 2010 Mortality and cardiovascular event free survival in patients with and without CAC No CAC CAC Roe, Rosas, Atherosclerosis, 2010

Coronary calcification predicts cardiovascular events and mortality Roe, Rosas, Atherosclerosis, 2010

Change in CAC score over time in renal transplant recipients Schankel, Rosas AJT 2007

Schankel, Rosas AJT 2007

Roe, Rosas, Atherosclerosis, 2010 Coronary calcification progression predicts cardiovascular events and mortality n = 87 Roe, Rosas, Atherosclerosis, 2010

Sylvia.rosas@uphs.upenn.edu