Enhanced Kupffer cell activity after repeated hepatic arterial ischaemia in an experimental model.

Kupffer cells are important for host defence against both foreign invaders and neoplasia. Several studies have demonstrated that ischaemia and reperfusion activates Kupffer cells. The effect of hepatic arterial ischaemia on Kupffer cell function was assessed using blood clearance and organ uptake of radiolabelled Escherichia coli. Transient ischaemia for 1 h did not alter Kupffer cell function in comparison with sham operation. However, prolonging arterial ischaemia for 2 h stimulated Kupffer cell function; both the phagocytic index and liver uptake of radiolabelled E. coli increased significantly (P < 0.01). Furthermore, this enhanced Kupffer cell activity was achieved each time the ischaemia was induced over a period of 5 days compared with repeated sham procedures (P < 0.05). Serum tumour necrosis factor (TNF) was significantly released after both single and repeated arterial occlusion for 2 h (P < 0.01). These observations show that transient arterial ischaemia enhances Kupffer cell function and induces TNF production.