908 EFFECTS OF ALISKIREN, IRBESARTAN AND THE COMBINATION ON URINARY LEVELS OF ANGIOTENSINOGEN AND RENIN IN PATIENTS WITH TYPE 2 DIABETES, HYPERTENSION AND ALBUMINURIA

Abstract

Introduction and Aim: Urinary levels of RAAS components are considered to reflect the intrarenal renin-angiotensin-aldosterone system (RAAS). We measured urinary levels of angiotensinogen and renin to gain information on treatment response to aliskiren and irbesartan treatment. Methods: We measured urinary levels of angiotensinogen and renin in 19 patients with type 2 diabetes, hypertension and albuminuria, during 2 month treatment periods with placebo, aliskiren 300 mg once daily, irbesartan 300 mg once daily or their combination. Levels were correlated with levels of albuminuria, and changes in urinary markers were correlated with change in albuminuria. Urine/plasma (U/P) concentration ratios of markers were also compared. Results: We found a significant reduction in urinary renin compared to placebo during aliskiren treatment (-3.3 [5.0]) pg/ml, p = 0.006), and during combination treatment (-3.2 [4.8]) pg/ml, p = 0.005). The reduction with irbesartan was not significant (-0.7 [2.7], p = 0.25). Irbesartan treatment led to a significant reduction in urinary angiotensinogen (0.05 [0.09] pmol/ml, p = 0.021) and so did combination therapy (0.09 [0.09] pmol/ml, p < 0.001), but not aliskiren treatment. Urinary angiotensinogen was associated with albuminuria during all treatment periods. A significant association between change in urinary renin and albuminuria was found during aliskiren treatment, r2 = 0.273, p = 0.013, but not in the other treatment periods. Angiotensinogen U/P correlated strongly to albuminuria, suggesting it as a marker of glomerular damage. Conclusion: Aliskiren monotherapy led to a reduction in urinary renin, and the change was correlated to change in albuminuria. This could point to a specific renal effect of renin inhibition.