Filtration as the main mechanism of increased protein extravasation in liver cirrhosis

Abstract

Transvascular escape rates of albumin and immunoglobulin-G, IgG (TER_alb and TER_IgG, i.e. the fractions of intravascular mass of albumin and IgG passing to the extravascular space per unit time) were determined simultaneously from the disappearance of intravenously injected ¹³¹I-labelled human serum albumin and ¹²⁵I-labelled human IgG in eight patients with cirrhosis of the liver. The mean wedged hepatic venous pressure was 22 mmHg (range 13-34). TER_IgG and TER_alb were on average 8.4± 0.8 %/h (SD), and 7.4 ± 1.9 %/h (SD), respectively and these values are significantly increased compared to normal subjects [TER_alb = 5.2±1.0 %/h (SD) and TER_IgG = 3.0 ± 0.7 %/h (SD), PIgG/TER_alb ratio was on average 0.88 ± 0.20 (SD), which is significantly higher than that of normals [0.58 ± 0.08 (SD), P<0.005]. The results indicated that increased filtration (bulk flow) is the dominant process of the increase microvascular protein escape in cirrhosis, due most likely to increased hepatic, but also to increased extrahepatic splanchnic transcapillary protein flux.