The effect of adrenergic innervation and/or circulating catecholamines on the function of liver fibrogenic cells is poorly understood. Our aim was to investigate the effects of noradrenergic antagonism on carbon tetrachloride (CCl 4 )-induced liver fibrosis in rats. Two weeks of CCl 4 induced a ϳ5-fold increase in the area of fibrosis as compared with controls. The addition of 6-hydroxydopamine (OHDA), a toxin that destroys noradrenergic fibers, decreased fibrosis by 60%. After 6 weeks of CCl 4 , the area of fibrosis increased about 30-fold in CCl 4 -treated animals and was decreased by 36% with OHDA. At 2 weeks, OHDA abrogated the CCl 4 -induced increase in mRNA level of tissue inhibitor of matrix metalloproteinases-1 (TIMP-1), an inhibitor of extracellular matrix degradation, and it greatly reduced it at 6 weeks. Finally, when rats treated with CCl 4 for 2 weeks also received prazosin, an antagonist of ␣ 1 -adrenergic receptors, fibrosis was decreased by 83%. In conclusion, destruction of noradrenergic fibers or antagonism of noradrenergic signaling through ␣ 1 receptors inhibited the development of liver fibrosis. Because adrenoreceptor antagonists have a very sound safety profile, they appear as attractive drugs to reduce liver fibrogenesis. (HEPATOLOGY 2002; 35:325-331.)

We have previously shown that human liver myofibroblasts promote in vitro invasion of human hepatocellular carcinoma (HCC) cells through a hepatocyte growth factor (HGF)/urokinase/plasmin-dependent mechanism. In this study, we demonstrate that myofibroblasts synthesize the serine proteinase inhibitor tissue factor pathway inhibitor-2 (TFPI-2). Despite the fact that recombinant TFPI-2 readily inhibits plasmin, we show that it potentiates HGF-induced invasion of HCC cells and is capable of inducing invasion on its own. Furthermore, HCC cells stably transfected with a TFPI-2 expression vector became spontaneously invasive. HCC cells express tissue factor and specifically factor VII. Addition of an antibody to factor VII abolished the pro-invasive effect of TFPI-2. We suggest that TFPI-2 induces invasion following binding to a tissue factor-factor VIIa complex preformed on HCC cells. Our data thus demonstrate an original mechanism of cell invasion that may be specific for liver tumor cells.Hepatocellular carcinoma (HCC) 1 is one of the most frequent primary tumors in the world (1). It is a major complication of liver cirrhosis, although more rarely it will develop on a noncirrhotic liver. HCC are characterized by a high rate of local, intra-hepatic invasion. HCC are infiltrated by myofibroblastlike cells, located around tumoral sinusoids and in fibrous septa and capsule, when present (2-4). We have previously shown that cultured human liver myofibroblasts strongly promoted in vitro invasion of human HCC cell lines through their secretion of hepatocyte growth factor (HGF) (5). In further studies, we showed that HGF induced invasion by increasing the expression of the urokinase-type plasminogen activator (uPA) by the cancer cells (6). Indeed, myofibroblast-or HGFinduced invasion was dose-dependently blocked by a selective uPA antagonist (6). One of the main functions of uPA is to convert the inactive zymogen plasminogen into plasmin, a broad-spectrum proteinase able to degrade several components of the extracellular matrix and thus a likely effector of cancer cell invasion.Tissue factor pathway inhibitor-2 (TFPI-2), also known as placental protein 5 is a serine proteinase inhibitor containing 3 tandemly arranged Kunitz-type proteinase inhibitor domains, homologous to tissue factor pathway inhibitor (7). TFPI-2 exists as 3 isoforms of 27, 31, and 33 kDa that are synthetic products of a single gene and arise from differential glycosylation. TFPI-2 is a strong inhibitor of plasmin as well as of trypsin, plasma kallikrein, and factor XIa. It does not inhibit uPA (8). TFPI-2 synthesis has been described in dermal fibroblasts and endothelial cells (9 -11). In these cell types, the major part of TFPI-2 is sequestered within the extracellular matrix (ECM), presumably bound to heparan sulfate. In the course of a systematic sequencing of a human liver myofibroblast cDNA library described elsewhere (12), we found that these cells expressed transcripts for TFPI-2. Given the ability of TFPI-2 to inhibit plasmin, we were interest...

The oral administration of selenium (Se) to young rats induces, over a 2-month period, the formation of nodular regenerative hyperplasia with sinusoidal damage around nodules. Perinodular areas located in zone 1 comprise atrophic hepatocytes and capillarized sinusoids without fibrosis. We used this unique model of capillarization without fibrosis to investigate the temporal relationship between the process of capillarization and changes occurring in the deposition of components of the extracellular matrix. After 2 weeks of intoxication, type III collagen and fibronectin were stable, but laminin and type IV collagen had increased in zone 1, resulting in the formation of septae between portal tracts. Even at 8 weeks, these two components still formed the principal deposits in perinodular zones. Electron microscopy showed already at 1 week in zone 1 that part of the endothelial wall had detached from hepatocytes. Sinusoidal endothelial cells progressively acquired certain of the characteristics of a vascular endothelium, some proliferated, and perisinusoidal cells transformed into myofibroblasts, surrounded by deposits of laminin and type IV collagen. These results indicate that both laminin and type IV collagen are involved in capillarization without fibrosis and in angiogenesis; fibronectin would not seem to play a role.

Weaned male rats were fed a 4 ppm selenium diet. Compared after 2 mo with a control group fed a 0.4 ppm diet, the rats' body weights had not significantly decreased and liver function was normal, but portal pressure was 1.8 times higher (p less than 0.05). Liver weight was slightly increased (10.3%; p less than 0.05). All livers had an abnormal appearance. In the less severe cases the surface was only slightly irregular, but in the more severe cases, atrophic micronodular lobes and hypertrophic lobes, with mildly irregular surfaces, were present. On light microscopy, atrophic lobes displayed a peripheral nodular zone with micronodules separated by rows of atrophic hepatocytes without fibrosis, characteristic of nodular regenerative hyperplasia, and a central atrophic zone that was sometimes peliotic. Hypertrophic lobes and livers in the less severe cases had only minor and relatively localized evidence of nodular regenerative hyperplasia; occasional peliosis was seen. In all cases portal veins, hepatic veins and hepatic arteries were normal. By electron microscopy, in nonnodular zones with no obvious evidence of parenchymal atrophy, the endothelial wall showed signs of complete or incomplete capillarization with frequent enlargement of the Disse space. The selenium-enriched diet is a reproducible model of liver nodular regenerative hyperplasia. In this model, damage to the sinusoidal wall could represent the primum movens of microcirculatory disturbances.

With indirect methods, it was shown in rats with portacaval shunts (PCS) that total hepatic blood flow (THBF) remained constant when expressed per gram of liver. These results implied an absolute increase in hepatic arterial blood flow (HABF). The aim of this study was to investigate HABF and splanchnic nonhepatic arterial blood flow (SNHABF) with a direct method (57Co microspheres) in PCS rats. One month after surgery, the following results were obtained in PCS rats compared with pair-fed, sham-operated rats: 1) liver mass atrophy was 42.3 +/- 10.9%, 2) HABF (ml X min-1 X g liver-1) was increased by a factor of 2.7, 3) SNHABF (ml X min-1 X 100 g body wt-1) was higher (9.8 +/- 3.3 vs. 5.6 +/- 2.7) (P less than 0.05) and 4) THBF (ml X min-1 X g liver-1) was decreased (1.36 +/- 0.34 vs. 1.85 +/- 0.86) but not significantly. Increases in HABF and SNHABF were not the direct consequence of an increase in cardiac output as attested by a normal cerebral blood flow (ml X min-1 X g organ-1) in PCS rats. In PCS rats, an increase in HABF may prevent the further spread of liver necrosis. The cause and the reason for an increase in SNHABF remain unknown.