Dissecting the pathogenesis of diabetic kidney disease

Transcription

1 Dissecting the pathogenesis of diabetic kidney disease Bryan Conway Scottish Senior Clinical Fellow/Honorary Consultant Nephrologist University of Edinburgh/Royal Infirmary Edinburgh

2 Overview Epidemiology of diabetic nephropathy (DN) Dissecting the pathogenesis of DN: o o Animal models Human disease Integrating animal and human data

3 Diabetic nephropathy (DN) is the most common cause of ESRD in UK Source: UK Renal Registry

4 Median survival on dialysis by diagnosis and age-group Scottish life expectancy data Source: Scottish Renal Registry

5 Prevalence of CKD in Lothian diabetic population CKD stage Number of patients %age of patients 1 2, , , Total 24, Source: Scottish Care Information: Diabetes Collaboration

6 CKD as a risk factor for cardiovascular disease Stage 3 Stage 4 Increasing cardiovascular risk Stage 5 Dialysis Death

7 CKD is a risk factor for cardiovascular disease Go et al. NEJM 2004;351:

8 CKD as a risk factor for cardiovascular disease Stage 3 Stage 4 Risk factors Diabetes Hypertension Smoking Dyslipidaemia Family history Increasing cardiovascular risk Stage 5 Dialysis Death

9 CKD as a risk factor for cardiovascular disease Stage 3 Stage 4 Risk factors Diabetes Hypertension Smoking Dyslipidaemia Family history Causality Renovascular disease Hypoperfusion Atheroemboli Increasing cardiovascular risk Stage 5 Dialysis Death

10 CKD as a risk factor for cardiovascular disease Stage 3 Stage 4 Risk factors Diabetes Hypertension Smoking Dyslipidaemia Family history Causality Renovascular disease Hypoperfusion Atheroemboli Increasing cardiovascular risk Stage 5 Dialysis Causality Classical Renal specific Anaemia Arterial calcification Death

11 Dissecting the pathogenesis of DN Animal models

12 Advantages of animal models Can determine causality v association with disease Useful for testing novel therapeutic agents

13 Natural history of diabetic nephropathy Stage 1 Stage 2 Stage 3 Stage 4 Stage 5 Pre-nephropathy Normoalbuminuria Incipient nephropathy Overt nephropathy Chronic renal failure Adapted from Mogensen et al, Diabetologia 1979; 17: 71-76

14 Normal glomerulus Early DN Late DN

15 Ideal animal model of DN (AMDCC guidelines) Progressive albuminuria (>100 fold normal) Decline in GFR >50% normal Pathology: Mesangial sclerosis Arterial hyalinosis GBM thickening >150% baseline Tubulo-interstitial fibrosis

16 Natural history of diabetic nephropathy Stage 1 Stage 2 Stage 3 Stage 4 Stage 5 Pre-nephropathy Normoalbuminuria Incipient nephropathy Overt nephropathy Chronic renal failure Adapted from Mogensen et al, Diabetologia 1979; 17: 71-76

17 Key role for hypertension in diabetic nephropathy Parental risk of hypertension confers increased risk of nephropathy in patients with diabetes Treatment of hypertension is at least as important as good glycaemic control High blood pressure is a requirement for DN

18 Diabetes with unilateral renal artery stenosis Diabetic glomerulosclerosis Normal kidney Berkman J, Rifken H. Metabolism 1973;22: Berionade VC, et al. Am J Nephrol 1987;7:55

19 Conditional mren2 rat model (Cyp1a1mRen2 rat) Indole-3-carbinol Cyp1a1 promoter mren2 cdna mren2 expression Titrable and reversible hypertension Kantachuvesiri et al. J.Biol.Chem 2001;276:

20 Conditional mren2 rat Citrate buffer 2wks Streptozotocin 2wks No HTN (n=6) HTN (n=8) No HTN (n=6) HTN (n=8) 28wks 28wks Readouts: Clinical: albuminuria, creatinine and inulin clearance Histological: glomerulosclerosis, tubulointerstitial fibrosis, M recruitment Microarray: determine molecular signature of interaction between hyperglycaemia and hypertension

21 Blood sugar (mm) Glycaemic control Blood sugar Cont Diabetic alone HTN alone Diabetic and HTN Time (wks)

22 Systolic BP (mmhg) Blood pressure 2wklyBP Cont Diabetic alone HTN alone Diabetic and HTN Time (wks)

23 ACR (mg/mmol) Albumin:creatinine ratio ACR ### $$ ### ### *** *** *** $ ### *** ### *** 1000 ### ### *** ***## # *** ### # ## *** *** *** 0 *** *** *** *** Time(wks) Cont Diabetic alone HTN alone Diabetic and HTN

24 GFR (ml/min) Trend towards reduced renal function in hypertensive animals 4 Terminal GFR Cont DM HTN DM+HTN

25 Cont DM HTN DM+HTN

26 Glomerulosclerosis index Synergistic increase in glomerulosclerosis in DM+HTN ** ## $ Cont DM HTN DM+HTN **<0.01 v Cont or DM; ## P<0.01 v DM; $ p<0.05 v HTN

27 Cont DM HTN DM+HTN

28 Percentage area Picosirus Red positive Increase in interstitial fibrosis in HTN and DM+HTN PicRed Quantification CON DM HTN DM+HTN * *** # *p<0.05 and ***p<0.001 v Cont #p<0.05 v DM

29 No.of ED-1 positive cells/ x200-power field No.of CD3+ve cells/ x200-power field Interstitial macrophage and T-cell infiltration CD *** ### *** ### $ *p< v control #p< v STZ ##p<0.001 v STZ 10 5 # *** ### $$ 0 Cont DM HTN DM+HTN 0 CON DM HTN DM+HTN ***p<0.001 v Cont; #p<0.05 and ###p<0.001 v DM; $p<0.05 v HTN

30 Up-regulated genes Down-regulated genes DM HTN DM HTN DM+HTN DM+HTN

31 The gene expression in diabetic rats mimics that in the tubulointerstium in human DN Human DN DM+HTN rats 50%

32 Summary Cyp1a1mRen2 rat model of DN mimics human disease: Progressive, severe albuminuria Trend to decline in renal function Histological features: glomerulosclerosis tubulointerstitial fibrosis Transcriptome