Renin-angiotensin system blockade in biopsy-proven allograft nephropathy

The role of renin-angiotensin system in the chronic allograft nephropathy: an immunohistochemical study

BACKGROUND

Evidences suggest a role of renin-angiotensin system (RAS) in the development of chronic allograft injury.

METHODS

We correlated intrarenal angiotensin-converting enzyme, angiotensin II (Angio II) and transforming growth factor β1 (TGFβ1) expression in 58 biopsies-proven chronic allograft nephropathy (CAN) with tissue injury and allograft survival.

RESULTS

The biopsies with CAN were graded according to Banff classification as I (22 cases), II (17) and III (19); 27 biopsies also showed a mononuclear inflammatory infiltrate in scarred areas. There were increased expression of angiotensin converting-enzyme (ACE), Angio II and TGFβ1 mainly in tubulointerstitial compartment in the group with CAN; there was no association of Angio II and TGFβ1 expression with interstitial fibrosis. There were no significant differences of ACE, Angio II and TGFβ1 expression between the patients treated and untreated with RAS blockade, and with the graft outcome. Interstitial inflammatory infiltrate had positive correlation with interstitial fibrosis and significant impact on graft survival at 8 years.

CONCLUSIONS

Our study showed in a group of cases with CAN a high percentage of inflammatory infiltrate that correlated with interstitial fibrosis and graft outcome. The chronic inflammatory changes in these cases did not show significant association with local RAS expression.

Efficacy and Safety of Valsartan, an Angiotensin II Receptor Antagonist, in Hypertension After Renal Transplantation: A Randomized Multicenter Study

BACKGROUND

The prevalence of posttransplant hypertension is high, and it appears to be a major risk factor for graft and patient survival. The aim of this study was to assess the efficacy and safety of valsartan, an angiotensin-receptor blocker (ARB), in the treatment of posttransplant hypertension.

METHODS

A multinational, multicenter, prospective, randomized, double-blind, placebo-controlled study was performed on the treatment of hypertension (systolic blood pressure [BP] >/= 140 and/or diastolic BP >/= 90 mm Hg) in adult cyclosporin-treated renal transplant recipients randomized to receive either valsartan (80 mg once daily) or a matching placebo for 8 weeks. After the first 4 weeks, furosemide 20 mg twice daily was added on a open basis if systolic BP remained >/= 130 mm Hg and/or diastolic BP remained >/= 85 mm Hg.

RESULTS

One hundred fifteen (valsartan = 57, placebo = 58) uncontrolled hypertensive patients despite monotherapy for hypertension, other than angiotensin-converting enzyme inhibitor or ARB, were randomized. In the valsartan group, significant decreases were seen in systolic BP (from 153 +/- 11 to 140.9 +/- 18.35 mm Hg at 4 weeks, and 136.5 +/- 15 mm Hg at 8 weeks) and diastolic BP (from 93 +/- 9 to 85.2 +/- 11.28 mm Hg at 4 weeks, and 83.8 +/- 9.2 mm Hg at 8 weeks). There was no significant change in the placebo group. In the valsartan group, a statistically but not clinically significant reduction was observed in the mean hemoglobin concentration (12.9 +/- 1.6 g/dL versus 13.8 +/- 1.6 g/dL at 4 weeks, P < .01; and 12.3 +/- 1.6 versus 13.8 +/- 1.7 at 8 weeks; P < .001) as well as a significant increase in serum potassium (4.4 +/- 0.5 mmol/L versus 4.1 +/- 0.4 mmol/L at 4 weeks, P < .01) vs placebo.

CONCLUSIONS

Valsartan is effective in the treatment of posttransplant hypertension and is well tolerated.

[The significance of angiotensin converting enzyme inhibitors in therapy in chronic allograft nephropathy]

Angiotensin II plays a crucial role in pathologic processes of chronic allograft nephropathy (CAN) leading to chronic and progressive renal allograft dysfunction (CRAD). Systemic and glomerular hypertensions together with proteinuria occur in CAN under conditions of JGA hypertrophy with up-regulated RAS activity in the renal allograft, and they represent independent factors of rapid progression of chronic renal allograft failure. ACEi are safe and efficient antihypertensives with renoprotective effects in patients with CAN. Favorable response to ACEi has been reflected in diminished proteinuria, slow increase of creatininemia, regulation of arterial hypertension and better long-term survival of patients and kidney allografts. Our pilot study highlights the importance of ACEi therapy in CAN after renal transplantation from elder donors (>55 years).