To evaluate the proteinuria lowering efficacy as well as tolerability and safety of the renin inhibitor aliskiren compared with that of placebo and angiotensin converting enzyme inhibitor perindopril in patients with non-diabetic chronic renal disease.

Proteinuria is a major risk factor for progression to end-stage renal disease in both diabetic and nondiabetic nephropathies. Angiotensin II and aldosterone are the key players in the development of renal failure, either directly by promoting tissue fibrosis or indirectly through their action on glomerular hemodynamic and proteinuria. Therefore, pharmacological inhibition of the renin-angiotensin-aldosterone system (RAAS) may have a beneficial impact on proteinuria and chronic kidney diseases progression. Recently, renin inhibitors, a new class of drugs that selectively inhibits angiotensin II formation at the first step of the RAAS cascade has been introduced to clinical practice. Aliskiren is the first orally bioavailable direct renin inhibitor approved for the treatment of hypertension. Blood pressure (BP)-lowering effect of aliskiren is associated with a decreased generation of angiotensin I, as it blocks its generation from angiotensinogen, by inhibiting the active enzymatic site of renin. The investigators plan this study to evaluate the short-term effects of treatment with aliskiren to those of placebo and ACEI perindopril on proteinuria.

Inclusion Criteria:

• age 18-65 years
• chronic non-diabetic proteinuric nephropathy
• creatinine clearance above 30 ml/min
• stable proteinuria above 500 mg/ 24 hours
• blood pressure above 125/75 mmHg and below 150/95 mmHg
• no steroids or other immunosuppressive treatment for a minimum of six months before the study

Exclusion Criteria:

• unstable coronary heart disease
• decompensated congestive heart failure in the previous 6 months
• episode of malignant hypertension or stroke in the history
• diabetes
• creatinine clearance below 30 ml/min