Antiproteinuric effect of angiotensin-converting enzyme inhibition and C5b-9 urinary excretion in membranous glomerulonephritis.
BACKGROUND
Angiotensin-converting enzyme (ACE) inhibitors have an antiproteinuric effect in membranous glomerulonephritis (MGN). However, no studies have investigated whether this antiproteinuric effect is influenced by urinary C5b-9 excretion, a marker of immunological activity in this disease.


METHODS
Eleven patients with biopsy-proven MGN were treated with captopril for 8 weeks. The evolution of several clinical and biochemical parameters, including 24-h urinary protein excretion was evaluated every 4 weeks. Urinary C5b-9 excretion was measured at the onset and at the end of captopril treatment.


RESULTS
Patients with MGN had significantly higher C5b-9 excretions than a group of 14 healthy controls (89 +/- 23 vs 3.7 +/- 1.4 ng/mg UCr; P < 0.001). A significant correlation was found between urinary C5b-9 and the magnitude of proteinuria, both at the onset and at the end of treatment. After 8 weeks of captopril treatment, proteinuria had decreased from 8 +/- 1.8 to 5.2 +/- 1.3 g/day (P < 0.05). Four weeks after captopril discontinuation, proteinuria rose to 7.3 +/- 1.7 g/day (P < 0.05). A marked variability in the antiproteinuric response was observed, ranging from 0 to 85% with respect to baseline values. No correlation between decrease in proteinuria and baseline urinary C5b-9 levels was observed. Several patients with elevated urinary C5b-9 levels had captopril-induced decrease in proteinuria.


CONCLUSIONS
ACE inhibition induces an antiproteinuric effect in patients with MGN. The urinary C5b-9 excretion does not predict the magnitude of this response.
Praga
M
M
Department of Nephrology, Hospital 12 de Octubre, Madrid, Spain.
Paz Artal
E
E
Hernández
E
E
Segura
J
J
Moreno
M A
MA
Morales
J M
JM
Rodicio
J L
JL
D000328:Adult; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use*; D002216:Captopril / Q000627:therapeutic use*; D015938:Complement Membrane Attack Complex / Q000652:urine*; D005260:Female; D015433:Glomerulonephritis, Membranous / Q000188:drug therapy* / Q000652:urine*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011507:Proteinuria / Q000188:drug therapy*; D012016:Reference Values
D000806:Angiotensin-Converting Enzyme Inhibitors; D015938:Complement Membrane Attack Complex; D002216:Captopril