신증후군 환자에서 혈장 Protein C및 S의 임상적 의의

Abstract

Objectives. Patients with nephrotic syndrome have increased risk of various thromboembolic com- plications. Renal loss of regulatory proteins of the co- agulation system such as antithrombin III have been suggested as important underlying mechanism for thromboembolic tendency of nephrotic syndrome, but the precise mechanism has not been clearly recog- nized. Recently, the importance of protein C and pro- tein S as another major anticoagulant proteins has been established and researches have been performed to prove their roles in patients with nephrotic syndrome, but only yielded conflicting results. There- fore we undertook this study to evaluate the role of antithrombin III, protein C and S in nephrotic syndrome. Method: we measured plasma protein C activity, free protein S concentration and antithrombin III activity in 17 adult patients with NS. The data were compsred with those obtained in a control group of normal 20 adults. Results '. 1) Plasma antithrombin m activity in nephrotic syndrome group(69.2 ± 14.9% ) was significantly lower than found in the control group(104.6±6.5%, p<0.001). In 13(76.5% )patients among 17 nephrotic patients, plasma antithrombin Ul activity was below the normal range. Plasma protein C activity in ne- phrotic syndrome group(149.3±37.3%) was signifi- cantly higher than measured in control group(103.0 ±9.6%, p<0.001). In 14(82.4%) patients among 17 nephrotic patients, plasma protein C activity was above the normal range. But there was no significant difference in plasma free protein S concentration be- tween nephrotic syndrome group(91.2±22.5%) and normal control group(103.4 ± 11.0% ). 2) Most nephrotic patients with low antithrombin m activity had high plasma protein C activity, but there was no significant correlation between the val- ues of either assay. 3) In 7 patients with minimal change nephrotic syndrome, plasma protein C activity was significaltly higher than patients with other pathologic types of nephrotic syndrome(p<0.05). In all these 7 patients with minimal change nephrotic syndrome, plasma protein C activity was above the normal range, and plasma antithrombin III activity was below the nor- mal range. Conclusion .: These observations suggest that low plasma levels of antithrombin III activity may be the cause of increasing the risk of thromboembolic com- plications in patients with nephrotic syndrome, and increased plasma protein C activity in nephrotic pa- tients may afford some protection against the throm- botic diathesis associated with antithrombin III defi- ciency. Interestingly, in patients with minimal change nephrotic syndrome, plasma protein C activity was significantly higher than patients with other pathologic types of nephrotic syndrome, but further studies with more patients would be needed to prove its clinical significance.