Biomedical subjects

M Pinzani

Publications and source records attributed to M Pinzani.

At least 55 records · Page 3Linked to original sources

PubMed1998

Increased expression of monocyte chemotactic protein-1 during active hepatic fibrogenesis: correlation with monocyte infiltration.

Monocyte chemotactic protein (MCP)-1 is a chemoattractant and activator for circulating monocytes and T lymphocytes. We investigated MCP-1 protein and gene expression during chronic liver disease at different stages, using immunohistochemistry and in situ hybridization, respectively. In normal liver, a modest expression of MCP-1 was confined to few peri-sinusoidal cells and to bile duct epithelial cells. During chronic hepatitis, MCP-1 immunostaining and gene expression were evident in the inflammatory infiltrate of the portal tract. In tissue from patients with active cirrhosis, MCP-1 expression was clearly up-regulated and was present in the portal tract, in the epithelial cells of regenerating bile ducts, and in the active septa surrounding regenerating nodules. A combination of in situ hybridization for MCP-1 and immunohistochemistry showed that activated stellate cells and monocyte/macrophages contribute to MCP-1 expression in vivo together with bile duct epithelial cells. Comparison of serial sections of liver biopsies from patients with various degrees of necro-inflammatory activity showed that infiltration of the portal tracts with monocytes/macrophages is directly correlated with the expression of MCP-1. These data expand previous in vitro studies showing that secretion of MCP-1 may contribute to the formation and maintenance of the inflammatory infiltrate observed during chronic liver disease.

Adult↗

PubMed1997

Detection of cytochrome P4503A (CYP3A) in human hepatic stellate cells.

In this study we have investigated the occurrence of cytochrome P450 isoforms and of related cytochrome P450 reductase in human hepatic stellate cells (hHSC), a type of cell having relevant roles in physiopathological conditions of the liver. By performing immunoblotting of hHSC microsomes and immunofluorescence analysis associated to confocal laser microscopy we detected only P450 enzymes belonging to the cytochrome P450 3A subfamily (CYP3A) as well as cytochrome P450 reductase. The presence of CYP3A was further indicated by detection of testosterone 6beta-hydroxylase activity in hHSC microsomes. Other important human P450 forms were either undetectable (CYP1A2, CYP2E1, CYP2C8/9/19 and CYP4A) or bearly detectable (CYP1A1) in hHSC. This is the first study showing existence of active cytochrome P450 isoforms in human HSC.

Adipocytes↗

PubMed1997

Integrin-mediated stimulation of monocyte chemotactic protein-1 expression.

We investigated whether activation of integrin receptors could modulate the expression of monocyte chemotactic protein-1 (MCP-1) in human hepatic stellate cells (HSC), mesenchymal cells responsible for extracellular matrix synthesis within the liver. When compared to non-adherent cells, HSC plated on collagen types I or IV, or fibronectin, showed increased MCP-1 gene expression and protein secretion in the conditioned medium. Increased MCP-1 secretion was also observed when cells were plated on dishes coated with a monoclonal antibody directed against the beta1-integrin subunit, demonstrating that ligation of beta1-integrins is sufficient to stimulate MCP-1 expression. Conversely, integrin-independent cell adhesion on poly-L-lysine did not modify MCP-1 secretion. Disruption of the actin cytoskeleton by cytochalasin D blocked the collagen-dependent increase in MCP-1 secretion. Chemotactic assay of HSC-conditioned medium showed that HSC plated on collagen secrete higher amounts of chemotactic factors for lymphomonocytes, and that MCP-1 accounts for the great majority of this effect. These findings indicate a novel mechanism of MCP-1 regulation possibly relevant in those conditions where HSC interact with an altered extracellular matrix.

Cell Adhesion↗

PubMed1997

Ectopic expression of the calcium-binding protein parvalbumin in mouse liver endothelial cells.

To elucidate the physiological role of the Ca2+ binding protein parvalbumin, we have generated transgenic mice carrying the full-length complementary DNA (cDNA) of rat parvalbumin under the control of the heavy-metal inducible metallothionein IIA promoter. Immunohistochemical and biochemical methods have been used to detect the presence of ectopic parvalbumin expression in different tissues. Here we show the expression of parvalbumin in endothelial cells lining the liver sinusoids in situ and after isolation in vitro. The hemodynamic effects of endothelin 1, a peptide hormone mediating potent vasoconstriction via calcium signalling, were investigated in the mouse liver perfused in situ. Vasoconstriction, thought to be mediated by the Ito cell, was not affected in the transgenic animals, whereas microvascular exchange, probed with the multiple indicator dilution technique, was markedly decreased in normal mice but virtually not affected in the transgenic animals. This suggests that ectopically expressed parvalbumin is involved in the regulation of Ca2+ signals in the sinusoidal endothelial cells. This animal model could be of interest to those working on the physiology of liver circulation.

Animals↗

PubMed1997

Phosphatidylinositol 3-kinase is required for platelet-derived growth factor's actions on hepatic stellate cells.

BACKGROUND & AIMS: Platelet-derived growth factor (PDGF) is the most potent mitogen for hepatic stellate cells (HSCs) in vitro. The aim of this study was to investigate the role of phosphatidylinositol 3-kinase (PI 3-K) activation in mediating the biological effects of PDGF on cultured HSCs and its involvement in vivo. METHODS: HSCs were isolated from normal human livers. PI 3-K was assayed on phosphotyrosine or PDGF-receptor immunoprecipitates by in vitro kinase assay. RESULTS: Incubation of HSCs with PDGF caused a time-dependent increase in PI 3-K activity. Immunoprecipitation of PDGF-alpha and -beta receptors showed that both subunits associate with active PI 3-K in PDGF-stimulated HSCs. Wortmannin, a specific PI 3-K inhibitor, dose-dependently blocked PI 3-K activity induced by PDGF and inhibited DNA synthesis. PDGF (homodimer)-BB also stimulated HSC chemotaxis, which was inhibited by pretreatment with wortmannin. To explore the potential role of PI 3-K in vivo, liver homogenates from rats treated with CCl4 and from control rats were immunoprecipitated with anti-PDGF-beta-receptor antibodies. Liver injury was associated with increased PDGF-beta-receptor autophosphorylation, and greater PI 3-K activity associated with the receptor itself. CONCLUSIONS: This study shows that in cultured HSCs, PI 3-K activation is necessary for both mitogenesis and chemotaxis induced by PDGF and that this pathway is up-regulated during liver injury in vivo.

Androstadienes↗

PubMed1997

Effect of pentoxifylline on the degradation of procollagen type I produced by human hepatic stellate cells in response to transforming growth factor-beta 1.

1. Pentoxifylline (PTF) may act as a potential antifibrogenic agent by inhibiting cell proliferation and/or collagen deposition in cell type(s) responsible for the accumulation of extracellular matrix. The aim of the present study was to investigate at which level PTF may affect synthesis and degradation of type I collagen in human hepatic stellate cells (HSCs), a key source of connective tissue in fibrotic liver. 2. Procollagen type I synthesis and release were evaluated in cells maintained in serum free/insulin free medium for 48 h and then stimulated with transforming growth factor-beta 1 (TGF-beta 1) for different time periods in the presence or absence of PTF. TGF-beta 1 caused an upregulation of procollagen I mRNA levels with a peak increase after 3-6 h of stimulation. This effect was followed by an increase in both the cell associated and the extracellular levels of the corresponding protein, with a peak effect at 9-12 h after the addition of TGF-beta 1. Co-incubation with PTF slightly but consistently reduced basal as well as stimulated procollagen I mRNA levels, with negligible effects on the cell-associated expression of the corresponding protein. Conversely, PTF dose-dependently reduced procollagen type I levels detected in supernatants from unstimulated and stimulated cells. 3. Pulse-chase experiments employing L-[3H]-proline revealed that PTF was able to induce significantly the degradation of procollagen, mainly in the extracellular compartment. We next analysed the effect of PTF on the major pathway involved in type I collagen degradation. PTF did not affect the expression of metalloproteinase 1 (MMP-1) mRNA both in basal and stimulated conditions, whereas it markedly reduced the expression of tissue inhibitor of metalloproteinase 1 (TIMP-1) mRNA. Accordingly incubation with PTF increased the levels of 'activated MMP-1' in cell supernatants in both basal and stimulated conditions. 4. These results suggest that the antifibrogenic action of PTF on human HSCs is mainly mediated by extracellular collagen degradation rather than by a reduction of collagen synthesis.

Cells, Cultured↗

PubMed1997

Focal adhesion kinase and phospholipase C gamma involvement in adhesion and migration of human hepatic stellate cells.

BACKGROUND & AIMS: Hepatic stellate cells (HSCs) play a key role in the development of liver fibrosis. Integrin receptors contribute to the regulation cell adhesion and migration. The aim of this study was to evaluate the interaction between focal adhesion kinase (FAK) and phospholipase C gamma (PLC gamma) potentially involved in HSC integrin-mediated signaling pathways. METHODS: Interaction between FAK and PLC gamma was determined by immunoprecipitation and immunoblotting. HSC chemotactic activity was evaluated using the Boyden chamber technique. RESULTS: HSC adhesion to extracellular matrix components (collagen type I and IV, laminin, and fibronectin) and antibody-mediated beta 1 ligation elicited increased tyrosine phosphorylation of FAK. HSC adhesion to different extracellular matrix components did not result in PLC gamma tyrosine phosphorylation. However, HSC adhesion induced association between PLC gamma and FAK. All extracellular matrix components tested stimulated HSC chemotactic activity only at high concentrations. On the contrary, platelet-derived growth factor, homodimer BB (PDGF-BB), was able to stimulate HSC migration in a dose-dependent manner; this event, occurring in the presence of FAK phosphorylation, was associated to a dose-dependent PLC gamma tyrosine phosphorylation. CONCLUSIONS: These findings provide the first evidence that PLC gamma recruitment by FAK during HSC adhesion is an important process implicating a link between integrin and PDGF-mediated signaling pathways to regulate HSC adhesion and motility.

Becaplermin↗

PubMed1997

Arginine vasopressin induces contraction and stimulates growth of cultured human hepatic stellate cells.

BACKGROUND & AIMS: Hepatic stellate cells (HSCs) are perisinusoidal cells believed to participate in the regulation of hepatic blood flow because of their contractile properties and presence of receptors for several vasoactive factors. It is unknown whether HSCs have receptors for vasopressin, one of the most potent endogenous vasoconstrictors. This study investigated the existence of receptors for and the effects of arginine vasopressin (AVP) on cultured human HSCs. METHODS: intracellular calcium concentration ([Ca2+]i) and cell contraction were measured in individual cells loaded with fura-2 using a morphometric method with an epifluorescence microscope coupled to a CCD imaging system (Photometrics, Tucson, AZ). AVP-specific binding was measured with [3H]AVP. Mitogen-activated protein kinase (MAPk) activity and DNA synthesis were measured by in vitro phosphorylation of myelin basic protein and [3H]thymidine incorporation, respectively. Parallel experiments were performed in vascular smooth muscle cells. RESULTS: AVP elicited a dose-dependent increase in [Ca2+]i and contraction of HSCs. Moreover, AVP increased MAPk activity, DNA synthesis, and cell number. These effects were similar to those observed in vascular smooth muscle cells and were blocked by a V1 receptor antagonist. The existence of V1 receptors was further confirmed by binding studies. CONCLUSIONS: Human HSCs have V1-vasopressin receptors that induce effects similar to those observed in vascular smooth muscle cells. AVP may play a role in the regulation of HSC function.

Animals↗

PubMed1997

Neutrophil-derived superoxide anion induces lipid peroxidation and stimulates collagen synthesis in human hepatic stellate cells: role of nitric oxide.

Experimental evidence indicates that the lipid peroxidation of biological membranes is often associated with the development of liver fibrosis. We have studied the effect of neutrophil-derived reactive oxygen species (ROS) on collagen synthesis by human hepatic stellate cells (HSC), the major source of collagen in the liver, in a coculture system. Lipid peroxidation in the cocultures was evaluated in terms of either malondialdehyde (MDA) production or the formation of MDA/4-hydroxynonenal protein adducts. The expression of cellular messenger RNAs (mRNAs) was evaluated by either Northern blotting or RNAse protection assay. Nitric oxide (NO) synthase activity in cells was measured by [3H]citrulline formation from [3H]arginine. In vitro exposure of HSC to ROS resulted in the early induction of lipid peroxidation and was associated with a marked increase (threefold) of procollagen I mRNA expression and synthesis. The addition of antioxidants, such as vitamin E or superoxide dismutase (SOD), impaired this stimulation. The inhibition of neutrophil NO formation by N(G)-monomethyl-L-arginine made the ROS-induced stimulation of procollagen I more evident. The addition of xanthine/xanthine oxidase X/XO, a superoxide anion donor, to HSC cultures strongly increased procollagen I synthesis. This stimulation was hampered by the addition of both SOD and sodium nitroprusside (an NO donor). The contribution of HSC to the production of NO in our coculture system was negligible, because inducible NO synthase (iNOS) mRNA was almost undetectable in these cells, and also because the amount of NO produced by HSC stimulated with tumor necrosis factor alpha (TNF-alpha) and lipopolysaccharide (LPS) was 500 times less than that synthesized by neutrophils. In conclusion, these results indicate that neutrophil-derived ROS may contribute to the development of hepatic fibrosis associated with alcoholic hepatitis. NO produced by neutrophils may exert a "protective" antioxidant effect by operating as a scavenger of superoxide anion.

Humans↗

PubMed1997

Long course and prognostic factors of virus-induced cirrhosis of the liver.

OBJECTIVE: Chronic infection by hepatitis B virus (HBV) and hepatitis C virus (HCV) is now recognized as a major cause of liver cirrhosis. This study was aimed at evaluating the natural history of the disease in a large series of Italian patients with HBV- and HCV-related cirrhosis without portal hypertension at entry. METHODS: The clinical records of 405 patients (233 males, mean age 54 +/- 9 yr) with histologically proven cirrhosis (321 with HCV-related and 84 with HBV-related cirrhosis) and no clinical evidence of portal hypertension at entry were retrospectively examined to evaluate the occurrence of complications and the cumulative mortality rate during follow-up. RESULTS: Patients had a mean follow-up of 8 +/- 3 yr. The cumulative survival rate was 99.1% at 5 yr, 76.8% at 10 yr, and 49.4% at 15 yr. The age-adjusted death rate was 3.14 and 2.84 times higher than in the general Italian population in men and women, respectively. Only the bilirubin level was an independent indicator of survival. Esophageal varices, ascites, jaundice, hemorrhage, hepatic encephalopathy, and hepatocellular carcinoma significantly reduced the survival rate (major complications), whereas thrombocytopenia, diabetes, and cholelithiasis did not affect survival (minor complications). The incidence of hepatocellular carcinoma was similar in patients with either HBV- or HCV-related disease and was quite frequent, especially in males. CONCLUSIONS: This study demonstrates that the course of virus-induced liver cirrhosis is not influenced by the etiology of the disease and that the occurrence of complications significantly shortens life expectancy. The longer survival rate observed in this study is probably due to the fact that cirrhosis was here recognized by liver biopsy in the absence of clinical evidence of portal hypertension.

Bilirubin↗

PubMed1997

Arachidonic acid derivatives and renal function in liver cirrhosis.

Prostaglandins (PGs) are arachidonic acid (AA) derivatives via the PG endoperoxyde H synthase (PGHS) complex. Two PGHS isoforms have been recognized, constitutive (PGHS-1) and inducible (PGHS-2), respectively. Within the kidney, vascular endothelium mainly produces PGI2; the whole glomerulus synthesizes several prostanoids, the predominant AA metabolite in humans being PGI2; tubules and medullary interstitial cells produce mainly PGE2. Renal PGs modulates the action of other hormones and autacoids involved in the regulation of renal hemodynamics, glomerular filtration and the renal handling of sodium and water. Renal PGs are, at least in part, excreted into urine. Measurement of urinary PGs or their metabolites has been found to provide a reliable estimation of basal as well as stimulated PG synthesis. Patients with cirrhosis of the liver show an increased renal synthesis of vasodilating PGs, as indicated by the high urinary excretion of PGs and/or their metabolites. Administration of nonsteroidal anti-inflammatory drugs (NSAIDs) to these patients causes a profound reduction in renal blood flow and glomerular filtration rate, a reduction in sodium excretion, and an impairment of free water clearance. These data clearly indicate that the increased renal synthesis of vasodilating PGs has a relevant role in maintaining renal hemodynamics, sodium and water excretion in a clinical setting characterized by a reduction of effective plasma volume and a striking activation of the major vasoconstricting systems, namely the renin-angiotensin-aldosterone, the sympathetic nervous system, and vasopressin. Patients with hepato-renal syndrome have a reduced renal synthesis of vasodilating PGE2 in the setting of a striking activation of endogenous vasoconstrictors and a maintained or increased renal production of thromboxane A2. Therefore, an imbalance between vasoconstricting systems and the renal vasodilator PGE2 was proposed to explain the renal failure observed in this condition. The urinary excretion of 2-3-dinor 6-keto-PGF1 alpha, an index of systemic PGI2 synthesis, is increased in patients with cirrhosis and hyperdynamic circulation, thus raising the possibility that systemic synthesis of PGI2 may contribute to the arterial vasodilatation of these patients. Finally, administration of exogenous prostanoids to patients with cirrhosis is not effective either in ameliorating renal function or in preventing the deleterious effect of NSAIDs.

Animals↗

PubMed1996

Induction of procollagen type I gene expression and synthesis in human hepatic stellate cells by 4-hydroxy-2,3-nonenal and other 4-hydroxy-2,3-alkenals is related to their molecular structure.

4-Hydroxy-2,3-nonenal (HNE) has been shown to induce procollagen type I gene expression and synthesis in hepatic stellate cells (HSC), i.e. the cells responsible for deposition of collagen and other extracellular matrix proteins in fibrotic liver. Here we report that the stimulatory effect of HNE mostly depends on the contemporary presence of the hydroxyl group in position C4 and of the double bond between position C2 and C3 since equimolar concentrations of 2,3-nonenal as well as of nonenal did not procollagen type I synthesis either at mRNA or at protein levels. Accordingly to this concept, all the other 4-hydroxy-2,3-alkenals of different chain length tested on cultured human HSC (4-hydroxy-2,3-hexenal, 4-hydroxy-2,3-octenal and 4-hydroxy-2,3-undecenal) strongly induced procollagen type I gene expression and synthesis. The stimulatory effect of 4-hydroxy-2,3-alkenals may depend on the well known ability of these aldehydes to react with either SH-groups or NH2-groups of functional proteins.

Aldehydes↗

PubMed1996

Endothelin 1 is overexpressed in human cirrhotic liver and exerts multiple effects on activated hepatic stellate cells.

BACKGROUND & AIMS: Endothelin (ET) 1 could be involved in the regulation of hepatic microcirculation and in the development of portal hypertension. The expression and distribution of ET-1 in normal and cirrhotic liver tissue and its effects on hepatic stellate cells (HSCs), liver-specific pericytes, were investigated. METHODS: ET-1 expression in liver tissue was analyzed using in situ hybridization and immunohistochemistry. Secretion of ET-1 by HSC was evaluated by radioimmunoassay. Changes in intracellular Ca2+ concentration and cell contraction were studied using digital video imaging. Specific binding of ET-1 was evaluated using self- and cross-displacement curves. RESULTS: ET-1 expression was markedly enhanced in cirrhotic liver tissue, where activated HSCs were shown to be major sites of ET-1 synthesis, as confirmed by studies performed on cultured human HSC. ET-1 exerted several biological actions on HSC, including mitogenicity, activation of mitogen-activated protein kinase, and a rapid increase in intracellular Ca2+ coupled with reversible cell contraction. All these effects appeared to be mediated by ETA receptors. Finally, the relative prevalence of ETA and ETB binding sites changed with the progressive phenotypical modulation of HSC. CONCLUSIONS: ET-1 may act as a paracrine and autocrine factor for activated HSC and contribute to the increased resistance to portal flow in cirrhotic liver.

Adipocytes↗

PubMed1996

Expression and function of integrin receptors for collagen and laminin in cultured human hepatic stellate cells.

BACKGROUND & AIMS: Human hepatic stellate cells (HSCs), liver-specific pericytes, are currently considered major producers of extracellular matrix (ECM) components and key elements in the development of liver fibrogenesis. However, little is known about the possible functional interactions between HSCs and the various ECM components. Therefore, the present study was designed to evaluate the expression of integrins, the major family of extracellular matrix receptors. METHODS: Integrin expression was evaluated by immunoprecipitation and confirmed by immunocytochemistry and flow cytometry. RESULTS: Human HSCs were shown to express alpha1beta1, alpha2beta1, alpha(v)beta1. Adhesion to type IV collagen, type I collagen, fibronectin, and laminin 1 was inhibited by anti-beta1 antibody identifying beta1-containing integrins as possible receptors for these components. In addition, we showed that HSCs express alpha6beta4, a heterodimer known to mediate adhesion of epithelial cells to laminin and not previously characterized in mesenchymal cells. Adhesion to laminin 1 was not inhibited by antibodies specific for alpha6 or beta4, thus establishing that laminin 1 is not a ligand for alpha6beta4 in this cell type. CONCLUSIONS: These findings represent the first description of integrin receptors in HSC and provide an attempt to cover the gap of information in the field of HSC-ECM interactions.

Adipocytes↗

PubMed1996

Inhibition by pentoxifylline of extracellular signal-regulated kinase activation by platelet-derived growth factor in hepatic stellate cells.

1. It has been proposed that pentoxifylline (PTF) acts an antifibrogenic agent by reducing the synthesis of extracellular matrix components, and this possibility has been confirmed in animal models of hepatic fibrosis. In this study the effects of PTF on the proliferation of extracellular matrix producing cells induced by platelet-derived growth factor (PDGF) were evaluated. The study was performed on hepatic stellate cells, currently indicated as the major source of extracellular matrix in fibrotic liver. 2. PTF caused a dose-dependent reduction of PDGF-induced mitogenesis with an IC50 of 170 microM, identical to the EC50 for the increase in intracellular cyclic AMP levels. Preincubation with PTF did not affect either PDGF-receptor autophosphorylation or phosphotidylinositol 3-kinase activity, whereas it markedly reduced PDGF-stimulated extracellular signal-regulated kinase (ERK) activity and ERK isoform phosphorylation. PTF also reduced PDGF-induced c-fos mRNA expression, which is dependent on activation of the RAS/ERK pathway. In addition, the PDGF-induced increase in cytsolic-free calcium was almost completely prevented by pretreating the cells with PTF. 3. The results of the present study indicate that PTF, in addition to its effect on collagen deposition and degradation, may exert an antifibrogenic effect by reducing the PDGF-induced proliferation of extracellular matrix producing cells. This effect appears to be mediated by a reduction of PDGF-stimulated ERK activity as well as of other intracellular signalling pathways such as the PDGF-induced elevation of cytosolic-free calcium.

Adipocytes↗

PubMed1996

Expression of platelet-derived growth factor and its receptors in normal human liver and during active hepatic fibrogenesis.

Expression of platelet-derived growth factor (PDGF) and its receptor (R) subunits was evaluated in normal human liver and in cirrhotic liver tissue by in situ hybridization and immunohistochemistry. In normal liver, PDGF and PDGF-R subunit expression was limited to a few mesenchymal cells of the portal tract stroma and vessels. In cirrhotic liver, PDGF-A and -B chain mRNA expression was markedly increased and was co-distributed with immunoreactivity for PDGF-AA and -BB in infiltrating inflammatory cells and along vascular structures within fibrous septa. These aspects were paralleled by a marked overexpression of PDGF-R alpha- and beta-subunit mRNAs and of the relative immunoreactivities in a wide range of mesenchymal cells in fibrous septa and in perisinusoidal alpha-smooth-muscle-actin-positive cells. In general expression and distribution of PDGF-R subunits appeared to be related to the activation of different mesenchymal cell types involved in the fibroproliferative process. Therefore, we evaluated the expression of PDGF-R subunits in liver tissue specimens with increasing degrees of necroinflammatory activity. The results of this additional study confirmed that expression of PDGF-R subunits is highly correlated with the severity of histological lesions and collagen deposition. Our results, providing evidence for a functional involvement of PDGF/PDGF-R in liver fibrogenesis, greatly support the results of previous in vitro studies and direct attention toward pharmacological strategies able to affect the series of signaling events arising from the autophosphorylation of PDGF-R subunits.

Chronic Disease↗

PubMed1996

[Viral liver cirrhosis: natural course, pathogenesis and clinical implications of the complications].

The role of hepatitis B virus (HBV) and hepatitis C virus (HCV) as a major cause of chronic liver disease is now accepted worldwide. This study was aimed at evaluating the natural history of the disease in patients with virus-induced chronic active hepatitis or cirrhosis, and the influence played by age, sex and etiology, liver function tests and by the occurrence of different complications. We retrospectively examined the clinical records of 506 inpatients: 194 were affected by chronic active hepatitis (125 males, 69 females, mean age 45 +/- 11 years, 146 HCV- and 48 HBV-related), and 312 by cirrhosis without clinical evidence of portal hypertension (178 males, 134 females, mean age 53 +/- 9 years, 249 HCV- and 63 HBV-related). The occurrence of cirrhosis in the chronic active hepatitis group was then calculated, together with the occurrence of complications and the cumulative mortality rate of established cirrhosis. During follow-up 93 patients with chronic hepatitis developed cirrhosis. The cumulative probability of developing cirrhosis in this group was 6.64% at 5 years, 56.1% at 10 years and 86.8% at 15 years. These patients were therefore included in the cirrhosis group for the final analysis, so that a total of 405 cirrhotic patients were evaluated: these patients had a cumulative survival rate of 99.1% at 5, 76.8% at 10 and 49.4% at 15 years. Comparing the age-adjusted death rate of our patients with the general Italian population, we observed that in patients with liver cirrhosis it was 3.14 and 2.84 times higher in men and women, respectively. Bilirubin was an independent indicator of survival. Several complications, such as esophageal varices, ascites, jaundice, hemorrhage, hepatic encephalopathy and hepatocellular carcinoma significantly reduced the survival rate and were indicated as major complications, while thrombocytopenia, cholelithiasis and diabetes did not affect survival and thus were called minor complications. Incidence of hepatocellular carcinoma was very high especially in males, without correlation with etiology. In conclusion, the progression of virus-induced chronic active hepatitis to cirrhosis is not influenced by sex and etiology. Similarly, the different etiology does not modify the natural history of cirrhosis while the occurrence of one or more major complications significantly shortens survival. The longer survival rate observed in patients with cirrhosis included in this study is probably due to the selective inclusion of patients with early disease and no evidence of portal hypertension.

Adult↗

PubMed1995

Involvement of phosphatidylinositol 3-kinase in the activation of extracellular signal-regulated kinase by PDGF in hepatic stellate cells.

Phosphatidylinositol 3-kinase (PI 3-K) is a lipid and protein kinase which associates with the activated platelet-derived growth factor (PDGF) receptor and other tyrosine kinases. We studied the effects of wortmannin, a selective inhibitor of PI 3-K, on the activation of extracellular-signal regulated kinase (ERK) by PDGF in cultured hepatic stellate cells, mesenchymal cells responsible for extracellular matrix synthesis within the liver. Incubation with 100 nM wortmannin, a dose which almost completely blocks PI 3-K, resulted in 50% reduction of ERK activity. Direct inhibition of ERK by wortmannin could not be considered responsible for this effect, since wortmannin did not inhibit ERK activity in vitro. Rather, inhibition of PI 3-K acts on the kinase cascade that leads to ERK activation, since PDGF-dependent phosphorylation of ERK was found to be reduced after incubation with wortmannin. Wortmannin also inhibited the increase in c-fos mRNA induced by PDGF, which is dependent on ERK activation. The results of this study show that in hepatic stellate cells PI 3-K is involved in ERK activation, although it is not necessary. These data indicate cross-talk between PI 3-K and the Ras/ERK pathway in PDGF-stimulated cells.

Androstadienes↗