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[The effect of angiotensin-converting enzyme inhibitors on proteinuria in chronic glomerulonephritis]
Insights
Lisinopril and captopril, both angiotensin-converting enzyme (ACE) inhibitors, were studied in patients with chronic glomerulonephritis. Lisinopril significantly reduced albuminuria, while both drugs affected plasma-renin activity differently.
Area of Science:
- Nephrology
- Pharmacology
- Cardiovascular Medicine
Background:
- Hypertension and chronic glomerulonephritis often lead to proteinuria and impaired renal function.
- Angiotensin-converting enzyme (ACE) inhibitors are commonly used to manage these conditions.
- The specific effects of lisinopril and captopril on proteinuria and renal hemodynamics require further elucidation.
Purpose of the Study:
- To compare the effects of lisinopril and captopril on proteinuria and renal hemodynamics in patients with chronic glomerulonephritis and impaired renal function.
- To investigate the impact of these ACE inhibitors on albuminuria, protein excretion, plasma-renin activity, and renal hemodynamics.
- To explore the independent effects of ACE inhibitors on the kidney's basal membrane.
Main Methods:
- A randomized, double-blind, cross-over trial involving 11 hypertensive patients with proteinuria and renal impairment.
- Patients received six-week treatments of either lisinopril or captopril, separated by four-week placebo phases.
- Measurements included protein excretion, fractional clearance of albumin and IgG, plasma-renin activity, and renal hemodynamics.
Main Results:
- Neither lisinopril nor captopril significantly reduced overall protein excretion.
- Lisinopril significantly decreased albumin excretion and fractional albumin clearance, unlike captopril.
- Both drugs increased plasma-renin activity, with a more pronounced effect from lisinopril. Captopril significantly decreased filtration fraction.
Conclusions:
- Lisinopril demonstrates a specific benefit in reducing albuminuria in patients with chronic glomerulonephritis and renal impairment.
- ACE inhibitors influence the renin-angiotensin-aldosterone system and may have independent effects on the glomerular filtration barrier.
- Further research is warranted to fully understand the differential effects of ACE inhibitors on renal outcomes.
Abstract:
The effect of two angiotensin-converting enzyme (ACE) inhibitors, lisinopril and captopril, on proteinuria and renal haemodynamics was investigated in 11 hypertensives (9 men, 2 women; mean age 46 +/- 16 years) with proteinuria (> 1.5 g/24 h) due to chronic glomerulonephritis and impaired renal function (glomerular filtration rate < 75 ml/min). In a randomized and double-blind cross-over trial the patients received, each time for six weeks, either lisinopril (5 mg/d, sometimes increased to 10 mg/d after 3 weeks) or captopril (twice daily 12.5 mg, sometimes increased to twice 25 mg after 3 weeks). Initially and between the individual treatment phases they were on a placebo phase for 4 weeks. The following were measured: protein excretion, including fractional clearance of albumin and IgG, plasma-renin activity and renal haemodynamics. Protein excretion was not significantly reduced by either drug (placebo: 7.1 +/- 4.0 g/d; lisinopril: 5.1 +/- 2.8 g/d; captopril: 5.4 +/- 3.0 g/d). Albumin excretion and fractional albumin clearance were significantly decreased only by lisinopril (P < 0.05), not by captopril. Plasma-renin activity was increased more by lisinopril than captopril (Placebo: 1.0 +/- 0.9 ng/ml.h; lisinopril: 5.2 +/- 2.8 ng/ml.h [P < 0.05]; captopril: 1.8 +/- 1.3 ng/ml.h [P < 0.05]). The renal haemodynamics was only slightly influenced by either drug, but captopril significantly decreased the filtration fraction in the presence of chronic glomerulonephritis and renal failure. - Resulting from their influence on the renin-angiotensin-aldosterone system, ACE inhibitors have, in addition to their known action on renal haemodynamics, an independent effect on the loading barrier of the basal membrane of the kidney.