Distribution ofplasminogen activator inhibitor in normal liver, cirrhotic liver, andliver with

Aims-To examinethedistribution of PAI-iantigen innormalandcirrhotic liver andliver withmetastases. Methods-Sections ofnormalandcirrhoticliverandliverwithmetastases werestained usingthealkaline phosphataseantialkaline phosphatase (APAAP) technique andmonoclonal antibody specific forplasminogen activator inhibitor (PAI-1). Results-PAI-i antigen wasidentified as discrete granules inthecytoplasm of hepatocytes innormalliver, particularly aroundportal tracts andcentral veins of theliverlobule. In cirrhotic livera striking reduction ofPAI-iantigen was noted. Inliver withmetastases increased amountsofPAI-iantigen wereconcentrated inhepatocytes aroundthemargins ofmalignant deposits. Conclusions-Cirrhotic livercontains considerably less PAI-Iantigen thandoes normalliver, despite raised plasmaconcentrations ofPAI-1.Thismay reflect release ofhepatic PAI-iintothecirculationor decreased clearance ofPAI-i fromtheplasma.Secondary malignant deposits intheliver seem tostimulate production ofPAI-iinadjacent hepatocytes. Thismay influence theinvasive process andmaycontribute tothethrombotictendency associated withmalignancy.