Haemostatic and immunological sequelae of portacaval shunt in rats

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Abstract
We have evaluated the link between haemostatic abnormalities and immune dysfunction in liver disease by evaluating parameters of cellular and humoral immunity in conjunction with coagulation profiles in rats following portacaval anastomosis, induction of portal hypertension by portal vein stenosis or by sham surgical procedures. Twelve weeks following surgery, portacaval shunted rats were markedly anaemic (8.9±0.6 g/dl; controls 12.3±1.4 g/dl, p>0.05), had low plasma fibrinogen levels (0.6±0.3 g/l, controls 2.5±0.2 g/l p>0.05) and markedly elevated fibrin(ogen) degradation products (FDP) titres (1/40–1/80; controls >1/10. p>0.05). Portal vein stenosed rats were less anaemic (11.5±0.8 g/dl), had near normal fibrinogen levels (2.1±0.3 g/l) but elevated FDP levels (1/40–1/80). Both portacaval shunted and portal vein stenosed rats had elevated serum IgG levels (35.1±14.1 g/l; 29.2±13.9 g/l respectively; control values 20±5.9 g/l p>0.05 for comparison with both experimental groups). Intrinsic lymphocyte proliferation to T and B cell mitogens was markedly depressed in the portacaval anastamosed rats when compared to controls. Serum factors inhibitory to control lymphocyte proliferation were noted in the shunted rats. Phagocytosis of complement and immunoglobulin sensitised sheep RBC by Kupffer cells purified from rats that had undergone portacaval shunting was markedly reduced (p>0.05). The increased degree of phagocytosis following exposure to LPS‐endotoxin (50 μg/ml) was proportionate in degree to the control group. Spontaneous release of bioactive lymphocyte activating factors (IL‐1 and IL‐6) by purified rat sinusoidal cell populations was decreased in the portacaval shunted group, and decreased still further following stimulation with LPS (50 μg/ml) in vitro. The observation that many of the haemostatic and immunological abnormalities associated with chronic liver disease are present in rats with surgically created portacaval shunts or with induced portal hypertension, lends credence to the hypothesis that shunting of portal blood is, at least in part, responsible for many of the systemic manifestations associated with chronic liver disease.