[Renal hemodynamics and proteinuria in chronic glomerulonephritis treated with beta-receptor blockers or ace inhibitors]

Abstract

Background and objective: In patients with chronic glomerular nephropathy associated arterial hypertension and proteinuria are considered to be cardinal risk factors in the progressive deterioration of renal function. Treatment regimens which reduce proteinuria and hypertension improve prognosis. The effect of the new beta-receptor blockers compared to common ACE-Inhibitors is of special interest.

Patients and methods: The studied cohort consisted of 11 patients with CGN, hypertension and proteinuria > 400 mg/24 h. Four drugs were given for 4 weeks, doubly blinded and randomized according to a "Latin-square design": Celiprolol (beta-1-antagonist, beta-2-agonist, 200 mg/d), Atenolol (selective beta-1-antagonist, 50 mg/d), Ramipril (ACE-inhibitor, 2.5 mg/d) and placebo. There was a two-week wash-out phase between each of the four treatment phases. At the end of each treatment phase glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were measured by inulin and para-amino-hippuric acid (PAH) clearance. Proteinuria was determined in the course of a three-day collection period at the end of each treatment phase. During this period blood pressures were measured with a continuous 24-hour blood pressure monitor.

Results: Mean arterial blood pressure (MAP) was significantly reduced, compared with placebo, by all three antihypertensives (108 +/- 9 mm Hg with placebo, 98 +/- 12 mg Hg with atenolol, 101 +/- 11 mm Hg with celiprolol and 98 +/- 8 mm Hg with ramipril; P < 0.01). Celiprolol produced a significant rise In ERPF (322 +/- 109 ml/min with placebo, 391 +/- 110 ml/min with celiprolol: P < 0.05). GFR was slightly, but not significantly, reduced by celiprolol and atenolol. Filtration fraction remained unchanged with atenolol and celiprolol, while it was slightly, but not significantly, reduced with ramipril. Compared with the placebo, all three drugs significantly reduced proteinuria (P < 0.05): 1.8 +/- 1.3 g/24 h with placebo, 1.2 +/- 1.2 g/24 h with atenolol, 1.2 +/- 1.1 g/24 h with celiprolol and 1.4 +/- 1.4 g/24 h with ramipril.

Conclusion: These data indicate that, in addition to ACE inhibitors, the new generation of beta-receptor blockers in particular, because of their vasodilator action, favourably influence proteinuria and renal blood flow in patients with CGN and arterial hypertension.