Protein C levels in nephrotic syndrome: use of a new enzyme-linked immunoadsorbent assay for protein C antigen.
Activated protein C is a potent, physiologic anticoagulant that inactivates the activated forms of factors V and VIII as well as facilitates in vivo fibrinolysis. We developed a competitive protein-binding enzyme-linked immunoadsorbent assay (ELISA) for protein C that was utilized to investigate if the hypercoagulability of the nephrotic syndrome is related to a deficiency of circulating plasma protein C. Protein C was measured in plasma of 11 patients with nephrotic syndrome (24 hr protein 8.4 +/- 1.6 g, SEM; serum creatinine 4.2 +/- .74 mg/dl, SEM). Ten azotemic nonnephrotic patients were employed as controls (serum creatinine 6.0 +/- 1.25 mg/dl, SEM). No significant reduction of protein C values was observed (mean 108%, range 65-200%) in nephrotic patients when compared with the controls (mean 127%, range 100-200%) even though protein C antigen was present in all nephrotic urine samples tested. Also, no correlation existed between blood levels of urea nitrogen, creatinine, albumin, total protein, or 24-hr urine protein excretion and the observed protein C values. These results suggest that in patients with the nephrotic syndrome, a hypercoagulable state may not be related to a deficiency of protein C and that the level of this zymogen in nephrotic syndrome reflects a dynamic balance between urinary losses and systemic production.
Soff
G A
GA
Sica
D A
DA
Marlar
R A
RA
Evans
H J
HJ
Qureshi
G D
GD
D000328:Adult; D000368:Aged; D001780:Blood Coagulation Tests; D004797:Enzyme-Linked Immunosorbent Assay; D005169:Factor VIII / Q000032:analysis; D006023:Glycoproteins / Q000032:analysis*; D006801:Humans; D008875:Middle Aged; D009404:Nephrotic Syndrome / Q000097:blood*; D011485:Protein Binding; D011486:Protein C
D006023:Glycoproteins; D011486:Protein C; D005169:Factor VIII