Levels of the human hepatocyte growth factor in serum of patients with various liver diseases determined by an enzyme-linked immunosorbent assay

Serum hepatocyte growth factor/scatter factor levels in small cell lung cancer patients

Serum hepatocyte growth factor/scatter factor (HGF/SF) levels were measured in 25 patients with small cell lung cancer (SCLC), 16 patients with benign lung diseases and 15 healthy subjects with an enzyme-linked immunosorbent assay. The patients with SCLC did not have bacterial or interstitial pneumonia. Patients with benign lung diseases included eight with bacterial pneumonia, three with interstitial pneumonia, and five with benign lung tumor. Serum HGF/SF levels were significantly higher in patients with SCLC (mean +/- S.D.: 0.40 +/- 0.17 ng/ml) than in healthy subjects (0.26 +/- 0.093 ng/ml) (P = 0.0083). Patients with bacterial pneumonia had significantly higher serum HGF/SF (0.52 +/- 0.19 ng/ml) than did those with benign lung tumors (0.27 +/- 0.058 ng/ml) and healthy subjects (P = 0.013 and P = 0.0019, respectively). By clinical stage of SCLC, HGF/SF levels were 0.34 +/- 0.12 and 0.47 +/- 0.20 ng/ml in patients with limited disease and extensive disease, respectively; this difference was not significant (P = 0.080). Although serum HGF/SF levels were increased in patients with SCLC, this increase might not have been related to tumor burden.

Hepatic expression of regeneration marker genes following partial hepatectomy in the rat. Influence of 1,25-dihydroxyvitamin D3 in hypocalcemia

BACKGROUND/AIMS

Vitamin D (D) depletion is a common feature of chronic liver diseases. In past years, disturbances in calcium metabolism involving inadequate D and parathyroid hormone status have been reported to significantly impair the hepatic regeneration process following partial hepatectomy in the rat. The purpose of this study was to investigate how hypocalcemia and D deficiency affect specific cell markers of hepatic compensatory growth.

METHODS

Steady-state mRNA levels of gene markers of the regeneration process were investigated following 2/3 partial hepatectomy. The response of hypocalcemic D-depleted rats was compared to that of animals whose calcium status had been normalized by repletion with the active D hormone 1,25-dihydroxyvitamin D3 (1,25(OH)2D3).

RESULTS

The transcript for the major hepatic mitogen HGF increased in both groups after partial liver resection but the increase was significantly lower as well as delayed in livers obtained from calcium deficient rats in the prereplicative phase of the regeneration process. TGF alpha mRNA levels were also found to be significantly lower in calcium deficient rats at all time-points following partial hepatectomy, while the relative behavior of the tandem TGF alpha-EGFR indicated an early dominant effect in normocalcemic 1,25(OH)2D3-repleted animals. HGF-c-met mRNA levels also indicated that the 1,25(OH)2D3-repleted animals reacted more promptly to the regeneration stimuli. Indeed, while relative (1,25(OH)2D3/D-Ca- ratio) maximum mRNA levels were observed 12 h following liver resection in 1,25(OH)2D3-treated animals, relative peak levels were only apparent 24 h post-surgery in hypocalcemic rats. Maximum cyclin D1 (a marker of the G1 phase of the cell cycle) mRNA occurred between 8-18 h after partial hepatectomy in 1,25(OH)2D3-repleted animals to return to base-line value thereafter, but in hypocalcemic rats the transcript levels remained significantly below 1,25(OH)2D3-repleted animals during the prereplicative period with increases above initial values between 12-24 h post-surgery. Both cyclin A (an S phase marker) transcripts (1.8 and 2.9 kb) were influenced by the regeneration process. The transcripts significantly and sharply increased in hypocalcemia between 30-36 h following partial hepatectomy to decrease thereafter, while the increase was observed between 24-30 h, and at 48 h (1.8 kb) in 1,25(OH)2D3-repleted animals. Liver weight recovery was also found to be decreased in D-depleted rats over the 48 h period of observation.

CONCLUSIONS

Our data further confirm the presence of an impaired regeneration process in hypocalcemia of D deficiency which seems to be associated with gene markers indicating an inefficient transit across the G1 phase of the cell cycle.

Hepatocyte growth factor in assessment of acute pancreatitis: comparison with C-reactive protein and interleukin-6

Serum levels of hepatocyte growth factor (HGF), C-reactive protein (CRP), and interleukin-6 (IL-6) were determined at the time of admission in 38 patients with acute pancreatitis. The clinical utility of HGF for the detection of severe pancreatitis and for predicting prognosis, bacterial infection (infected pancreatic necrosis or sepsis), and organ dysfunction (liver, kidney, and lung) during the clinical course of acute pancreatitis was compared with the clinical utility of CRP and IL-6 by analysis of receiver operator characteristic (ROC) curves. The optimum cutoff levels of HGF for severity, prognosis, infection, hepatic dysfunction, renal dysfunction, and respiratory dysfunction were 0.9, 1.1, 1.0, 1.1, 1.1, and 1.0 ng/ml, respectively. HGF was as useful as CRP and more useful than IL-6 for detection of severe pancreatitis and for predicting hepatic dysfunction. Moreover, HGF was more useful than CRP or IL-6 for predicting prognosis, renal dysfunction, and respiratory dysfunction. However, for predicting infection, CRP was more useful than HGF. These results suggest that serum HGF levels on admission may be a useful new clinical parameter for determining the prognosis of acute pancreatitis and that HGF may be closely related to the organ dysfunction of acute pancreatitis.

Hepatocyte growth factor(HGF): a new biochemical marker for acute myocardial infarction

The purpose of this study was to investigate the use of hepatocyte growth factor as a biochemical marker for acute myocardial infarction. Several biochemical markers are used for noninvasive detection of acute myocardial infarction. However, hepatocyte growth factor has not been used previously for this purpose. We measured hepatocyte growth factor, creatine phosphokinase, and MB isoenzyme (CK-MB) levels in 6 patients with stable effort angina after diagnostic catheterization (controls) and in 12 patients with acute myocardial infarction (AMI). The measurements in the AMI patients were recorded twice a day for the first 3 days after onset of chest pain and once a day for the next 4 days. Furthermore, in each patient we evaluated the time to reach the maximum level and the time for the level to decline to less than half the maximum. Hepatocyte growth factor levels (ng/ml) were 0.3+/-0.1 for angina pectoris patients, and 15.7+/-9.1 within 6h and 12.5+/-4.6 within 12h after the onset for AMI patients, respectively. The correlation coefficients between hepatocyte growth factor and creatine phosphokinase and between hepatocyte growth factor and CK-MB were 0.68 and 0.74, respectively. The time to reach the maximum (h) and the time to decline to less than half of the maximum level (days) were 6.6+/-2.6 and 1.2 +/-0.2 for hepatocyte growth factor, 19.4+/-8.7 and 2.5+/-1.4 for creatine phosphokinase, and 16.6+/-7.7 and 1.5+/-0.4 for CK-MB, respectively. Hepatocyte growth factor is useful as a prognostic indicator and reflects the clinical course in patients with acute myocardial infarction.

Immunodetection of c-met-oncogene's protein product in renal cell neoplasia

The proto-oncogene c-met encodes a transmembrane tyrosine kinase receptor for hepatocyte growth factor and is expressed in normal kidney tissue. This receptor may be involved in the carcinogenesis of various organs. The aim of this study was to investigate the relationship between c-met immunohistochemical expression and pathological tumor variables in human renal cell carcinomas (RCCs) and adenomas (RAs). Formalin fixed, paraffin embedded tissues from 35 RCCs, 16 RAs and 17 normal kidneys were immunostained (Strept. ABC/HRP) with a polyclonal antibody against c-met protein (Santa Cruz, Clone C-12). The statistical analysis was performed using the linear trend in proportions and Fisher's exact test. C-met protein was detected in the cytoplasm and the plasma membranes of neoplastic cells in 19/35 RCCs (54%), 10/16 adenomas (63%) (p = 0.41) and in 17/17 controls in the epithelial cells of distal renal tubules and collecting ducts. C-met protein expression was not related with gender (p = 0.45), age (p = 0.18), tumor size (p = 0.99), cell type (p = 0.26), grade (p = 0.86) and stage (p = 0.33). Moreover, c-met immunopositive tumor cell percentage and intensity were increased in stage [RCCs, but these results were not statistically significant. Apart from glandular differentiation, c-met protein expression was not related to other histopathological features (i.e. to the type of cells or to any selective overexpression in tumor cells). C-met product may be involved in the malignant transformation of tubular epithelial cells as an early event in RCC carcinogenesis. C-met expression does not seem to have any prognostic significance for RCCs, as it was not associated with any pathological prognosticator.

Increased production of interleukin 1 beta and hepatocyte growth factor may contribute to foveolar hyperplasia in enlarged fold gastritis

BACKGROUND AND AIMS

It has been reported that eradication of Helicobacter pylori improves fold width in H pylori associated enlarged fold gastritis. The aim of this study was to clarify the mechanism of fold thickening in this condition.

PATIENTS AND METHODS

In eight patients with enlarged fold gastritis and 13 patients without enlarged folds, the presence of H pylori infection, inflammatory infiltrates, mucosal plasia, and epithelial cell proliferation in the body mucosa were investigated, and production of transforming growth factor alpha (TGF alpha), hepatocyte growth factor (HGF), and interleukin 1 beta (IL 1 beta) was determined by a competitive reverse transcription/polymerase chain reaction method and in vitro short-term culture of biopsy specimens.

RESULTS

In the patients with enlarged fold gastritis, inflammatory infiltrates including macrophages increased with H pylori colonisation in the body. Foveolar thickness and proliferating cell nuclear antigen (PCNA) labelling index were increased. Messenger RNA levels of HGF, but not TGF alpha, were increased, and release of HGF and IL 1 beta was increased. HGF release, which was positively correlated with IL 1 beta release and foveolar thickness, decreased in the presence of IL 1 receptor antagonist. After eradication of H pylori, inflammatory infiltrates, IL 1 beta and HGF release decreased with concomitant decreases in PCNA labelling index, foveolar thickness and fold width.

CONCLUSIONS

Increased IL 1 beta and HGF production caused by H pylori infection may contribute to fold thickening of the stomach by stimulating epithelial cell proliferation and foveolar hyperplasia in patients with enlarged fold gastritis.

Human hepatocyte growth factor in alcoholic liver disease: a comparison with change in alpha-fetoprotein. Department of Veterans Affairs Cooperative Study Group 275

To evaluate the hepatic regenerative response in patients with alcoholic liver disease, sera from 263 patients with severe alcoholic hepatitis and/or cirrhosis were analyzed for hepatocyte growth factor (HGF) and alpha-fetoprotein (AFP). HGF concentration was elevated above healthy controls in 95% of the patients (median level = 2.4 ng/ml), whereas AFP tended to be depressed below controls (median level = 4.1 ng/ml). Correlations with parameters of liver injury (i.e., ascites, encephalopathy, AST bilirubin, and protime) all showed a more significant correlation with HGF concentrations than those of AFP. Patients with HGF levels below the mean (4 ng/ml) exhibited significantly better survival (median survival = 35 months vs. 8.5 months for those with HGF > or = 4 ng/ml; p = 0.007). Serum HGF levels were associated with various specific histologic features of alcoholic hepatitis that included, but were not exclusively related to, necrosis.

Thermolabile beta-2 macroglycoprotein (Hakata antigen) in liver disease: biochemical and immunohistochemical study

Thermolabile beta-2 macroglycoprotein is a novel serum protein that was detected by an autoantibody in sera of a Japanese woman with systemic lupus erythematosus. We developed an enzyme-linked immunosorbent assay for this glycoprotein and measured its serum levels in patients with chronic liver disease. There were significant correlations between serum levels of this glycoprotein and those of albumin and cholinesterase. The serum levels of TL beta 2MG decreased with increasing severity of cirrhosis. Immunohistochemical staining using monoclonal anti-thermolabile beta-2 macroglycoprotein antibody revealed positive staining in the cytoplasm of the hepatocytes. These data strongly suggested that hepatocyte may be one of the production sites of this glycoprotein. Measurement of serum levels of this glycoprotein was useful for evaluation of hepatic function in chronic liver disease.

Primary human fibroblasts induce diverse tumor invasiveness: involvement of HGF as an important paracrine factor

Fibroblasts have been considered to play an important role in tumor progression. In order to evaluate the contribution of fibroblasts to tumor invasion, TE2-NS, an esophageal cancer cell line, was cultured on collagen gel containing primary fibroblasts derived from normal esophageal submucosa or cancerous tissues of seven esophageal cancer patients. TE2-NS showed diverse invasiveness into the underlying gel containing fibroblasts, but did not invade the gel not containing fibroblasts. The invasiveness of TE2-NS, which expressed hepatocyte growth factor (HGF) receptor, was well-correlated with the concentration of HGF in conditioned medium. Administration of neutralizing antibody against HGF effectively suppressed the invasion, but application of recombinant HGF without fibroblasts induced little invasion into the gel. Fibroblasts from non-cancerous tissue generally secreted a larger amount of HGF and induced tumor invasion to a greater extent than those from cancer tissue, with large diversity. Interestingly, HGF secretion of fibroblasts from non-cancerous tissue was stimulated by co-culture with TE2-NS in two lines, but not in the other four. These results indicate that HGF is an important paracrine factor which induces tumor cell invasion, and the diversity of HGF production by fibroblasts might suggest different potentiality to induce tumor invasion among patients.

Contribution of primary cultures of adult human hepatocytes to the pathophysiology of hepatocellular carcinoma

BACKGROUND/AIMS

The mechanisms of hepatocarcinogenesis are still poorly understood. The development of hepatocellular carcinoma has recently been shown to be associated with increased DNA synthesis in cirrhosis. The aim of this work was to determine whether the high rate of hepatocyte regeneration observed in cirrhotic liver with hepatocellular carcinoma is associated with the presence of a growth factor that could be detectable in the serum.

METHODS

Adult human hepatocytes in primary culture, allowing the evaluation of the release of circulating hepatotrophic factors, were used. These cultures were treated for 48 h with serum from patients with cirrhosis with and without hepatocellular carcinoma, from patients with liver metastasis, and from healthy subjects. The rate of DNA synthesis in these cultures was assessed by measuring the amount of [3H]-thymidine incorporation into genomic DNA.

RESULTS

On average, the synthesis of DNA was increased 2.5-, 2.2-, 2.1-, and 2.3-fold, respectively, in response to serum from patients with cirrhosis with hepatocellular carcinoma, from patients with cirrhosis without hepatocellular carcinoma, from patients with liver metastasis, and from healthy subjects.

CONCLUSIONS

We conclude that the hepatotrophic activity of the serum is not significantly different in patients with cirrhosis with or without hepatocellular carcinoma. These results suggest that the increased DNA synthesis in hepatocytes of cirrhotic liver with hepatocellular carcinoma might be due to proliferative factor(s) acting by paracrine or autocrine pathways.

Hepatocyte growth factor mRNA in human liver cirrhosis as evidenced by in situ hybridization

BACKGROUND

Hepatocyte growth factor (HGF) is a strong mitogen of hepatocytes, and HGF-producing cells have been reported to be Ito cells or endothelial cells in the sinusoid of the liver. No reports have been published about the localization of HGF mRNA in human liver cirrhosis.

METHODS

In situ hybridization (ISH) for HGF mRNA was performed in 5 normal liver and 16 human liver cirrhosis specimens, using 1 RNA probe and 3 oligonucleotide probes labeled with 35S.

RESULTS

A positive signal was obtained in 15 of these cases. In five normal liver specimens, signals of HGF mRNA were not obtainable. In 13 of the 15 cases of liver cirrhosis, HGF mRNA was present in the periphery of the regenerative nodules. This peripheral pattern was seen in regenerative nodules with irregular nodule to septal interfaces. Combined immunohistochemistry and ISH showed that vimentin and CD 68-positive cells consistent with macrophages expressed HGF mRNA in such cases. In three specimens with diffuse signal for HGF mRNA in the hepatic nodules, signals localized to the sinusoidal spaces. HGF mRNA-positive cells were spindled and polygonal in shape, suggesting endothelial, Kupffer, and/or Ito cells of origin. In the diffuse pattern the peripheral margins of the regenerative nodules appeared well-defined. In one case regenerative nodules with both diffuse and peripheral signal patterns were present in the same section. There was no relationship among HGF mRNA, etiology, and macroscopic appearance of liver cirrhosis.

CONCLUSIONS

HGF gene transcription in human liver cirrhosis nodules may be heterogeneous, probably related to the degree of activity of the regenerative nodules. HGF appears to be produced by the mesenchymal cells, including Ito cells, macrophages (Kupffer cells), and endothelial cells in human liver cirrhosis.

Effects of hepatocyte growth factor (HGF) on human glioma cells in vitro: HGF acts as a motility factor in glioma cells

Expression of c-Met, the receptor for hepatocyte growth factor (HGF), and the biological roles of HGF were examined in cultured human glioma cells. All of the 5 glioma cell lines examined expressed c-Met protein as well as the c-met gene. Expression of the c-met gene was also confirmed in a glioblastoma tissue. Three cell lines (MGM-3, U251, KG-1-C) demonstrated chemotactic response to HGF in a dose-dependent manner. The response was not only chemotactic but also chemokinetic as judged by a checkerboard analysis. The amounts of c-Met mRNA and protein were abundant in the cell lines which showed a migratory response to HGF. Moreover, c-Met protein expression was highest in U251 with the highest migratory response to HGF. Among the cell lines, KG-1-C produced notable amounts of HGF protein as well as of c-Met, suggesting that HGF may act in an autocrine fashion in this case. HGF did not act as an apparent growth factor in the glioma cell lines examined. Furthermore, HGF stimulated the production of metalloproteinase, probably gelatinase A, in U251 cells.

Clinical significance of serum hepatocyte growth factor in orthotopic liver transplantation

BACKGROUND

Hepatocyte growth factor (HGF) plays a key role in the regulation of liver regeneration after hepatocyte damage. Changes in HGF production reflect the status of the regeneration process.

METHODS

Serum concentrations of HGF and energy substrates were measured during and after liver transplantation in 30 recipients.

RESULTS

In the patients with compromised grafts (group A) HGF concentrations were persistently high after reperfusion, whereas in the patients with well-functioning grafts (group B), HGF concentrations decreased rapidly and remained low 4 hours after reperfusion. The patients in group A who died had persistently high concentrations of HGF. The surviving patients with reversible primary graft dysfunction in group A exhibited low concentrations 48 hours after reperfusion. The decrease in HGF concentration preceded the decrease in aspartate aminotransferase concentration. The metabolic parameters that reflect carbohydrate metabolism by the graft paralleled the changes in HGF.

CONCLUSIONS

HGF may be more sensitive and specific in predicting early graft function than prothrombin time, ratio, aspartate aminotransferase, or arterial ketone body ratio. The determination of HGF levels after liver transplantation may yield valuable information for evaluating early graft function and making an early decision to repeat a graft procedure in an acutely ill patient.

Serum hyaluronate in patients with acute and fulminant hepatitis

We evaluated serum hyaluronate (HA) levels in 17 patients with acute hepatitis and 9 with fulminant hepatitis (FH). Upon admission, patients with FH showed increased levels of serum HA and these levels showed significant correlation with biochemical parameters such as human hepatocyte growth factor, hepaplastin test, and prothrombin activity. In patients with AH, the levels of serum HA decreased during convalescence. Higher serum HA levels were observed in patients with type A acute hepatitis than in patients with non-A type. In patients with FH, serum HA levels were decreased in the survivors, while they were elevated in the non-survivors. These findings suggest that serum HA levels may be a useful indicator for evaluating the prognosis of patients with acute and fulminant hepatitis. Further study is necessary to determine whether there is a causal relationship between elevated serum HA levels and the type of hepatitis virus.

Hepatocyte proliferation and serum hepatocyte growth factor levels in patients with alcoholic hepatitis

BACKGROUND/METHODS

Hepatocyte growth factor is thought to be important in stimulating growth of the liver following injury. In this study we have measured serum levels of hepatocyte growth factor together with hepatocyte proliferation in liver biopsies, by detection of the Ki-67 antigen, in 23 patients with alcoholic hepatitis.

RESULTS

Serum hepatocyte growth factor was elevated in all patients (median 0.9 ng/ml; range 0.6-7.7 ng/ml; normal < 0.5 ng/ml) and there was a positive correlation between hepatocyte growth factor levels and hepatocyte proliferation in the biopsies.

CONCLUSIONS

These results demonstrate that in acute alcoholic hepatitis the liver proliferates in response to injury and suggest that hepatocyte growth factor may be one of the growth factors responsible for this proliferative activity.

Lipoteichoic acid and interleukin 1 stimulate synergistically production of hepatocyte growth factor (scatter factor) in human gingival fibroblasts in culture

Lipoteichoic acids (LTA) from various gram-positive bacteria, including oral streptococci such as Streptococcus sanguis, enhanced the production of hepatocyte growth factor (HGF) (scatter factor) by human gingival fibroblasts in culture, whereas lipopolysaccharides (LPS) from various gram-negative bacteria did not. In contrast, LPS induced interleukin 1 activity in human gingival epithelial cells in culture, while LTA had little effect. LTA and recombinant human interleukin 1 alpha enhanced synergistically the production of HGF/SF in human gingival fibroblast cultures. Recombinant human HGF, in turn, enhanced the proliferation of human gingival epithelial cells in culture.

Serum HGF levels in acute renal rejection after living related renal transplantation

Hepatocyte growth factor (HGF), a long sought-after hepatotrophic factor, has recently been shown to act as a renotrophic factor in regeneration of the kidney. We investigated serum HGF levels in 16 renal transplant patients. In patients with acute rejection, the serum HGF level was markedly increased (over 1 ng/ml), and its elevation was accompanied by an increase in serum creatinine and blood urea nitrogen (BUN). In contrast, serum HGF levels were continuously low in patients without rejection. We conclude that serum HGF may become a clinically useful marker for the assessment of acute renal rejection.

Gene expressions of c-met and hepatocyte growth factor in chronic liver disease and hepatocellular carcinoma

BACKGROUND/AIMS

The roles of c-met proto-oncogene and hepatocyte growth factor in human livers have not been shown.

METHODS

Gene expressions of both c-met and hepatocyte growth factor were quantified in livers with chronic active hepatitis and in cirrhotic livers with hepatocellular carcinoma as well as in normal controls, using competitive reverse transcription polymerase chain reaction.

RESULTS

C-met expression was significantly increased in chronic active hepatitis compared with control livers, and c-met expression in chronic active hepatitis correlated with serum alanine aminotransferase levels. Hepatocyte growth factor expression was increased in some patients with chronic active hepatitis compared with controls, and there was a significant correlation between c-met expression and hepatocyte growth factor expression. On the other hand, in hepatocellular carcinoma tissues, c-met expression was increased in some cases, while that in the surrounding non-carcinomatous tissues was similar to normal controls. Hepatocyte growth factor expression was not detected in the hepatocellular carcinoma tissues and was low in the surrounding non-carcinomatous tissues.

CONCLUSIONS

These findings suggest that hepatocyte growth factor may be involved in the regeneration of hepatocytes via paracrine mechanism in chronic active hepatitis, while in regulation of c-met expression in hepatocellular carcinoma tissues may be independent of hepatocyte growth factor stimulation.

Activation of hepatocyte growth factor in the injured tissues is mediated by hepatocyte growth factor activator

Hepatocyte growth factor (HGF) is a potent mitogen, motogen, and morphogen for epithelial cells in vitro. It appears likely that HGF participates in tissue regeneration following hepatic and renal injury in vivo. The activity of HGF is localized to the injured tissues by a proteolytic activation system; HGF remains as an inactive single-chain form in the normal state and is converted to an active heterodimeric form in response to tissue injury. A protease responsible for this conversion is induced in the injured liver, but it has not yet been identified. We have previously purified and characterized HGF activator (HGFA), a serum-derived serine protease that efficiently activates single-chain HGF in vitro. In this study, we found that the HGF-converting activity in the injured liver was inhibited by an anti-HGFA antibody. We also found that the active form of HGFA was generated exclusively in the injured tissues. Thus, it appears likely that HGFA is the key enzyme that regulates the activity of HGF in the injured tissues. We also analyzed the heparin binding properties of the precursor and mature forms of HGFA. HGFA had a weak affinity for heparin near the physiological salt concentration in its precursor form but acquired a strong affinity for heparin upon activation that is linked to blood coagulation. This property may ensure the local action of this enzyme at the site of tissue injury.

Hepatocyte growth factor reverses the TGF-beta-induced growth inhibition of CCL-64 cells. A novel bioassay for HGF and implications for the TGF-beta bioassay

The influence of human hepatocyte growth factor (HGF) on the transforming growth factor beta (TGF-beta) bioassay CCL-64 was examined. HGF induced proliferation of the CCL-64 cells and potently counteracted TGF-beta-induced growth inhibition. HGF was not inactivated by transient acidification to pH 2, a commonly used procedure to activate latent TGF-beta. HGF was a stronger mitogen for the mink lung cells than epidermal growth factor (EGF), a known stimulator of CCL-64 cell growth. Costimulation of the cells by these two cytokines resulted in an additive effect on proliferation. In complex biological fluids containing large amounts of HGF, the TGF-beta concentration can be underestimated when determined by the CCL-64 assay. When a fixed amount of TGF-beta is added, the CCL-64 cells can be used as a reliable bioassay for HGF with a sensitivity of about 1 ng/ml.

Expression of immunoreactive human hepatocyte growth factor in human esophageal squamous cell carcinomas

Hepatocyte growth factor (HGF) is a potent mitogen for epithelial cells that promotes cell motility and invasiveness. In this study, we report that the human esophageal squamous cell carcinoma (SCC) shows a significant elevation of HGF concentration (600 +/- 416 ng/100 mg protein), compared to normal mucosa (80 +/- 183 ng/100 mg protein) (P < 0.01). An association could be established between levels of HGF and decreasing differentiation of 37 SCCs. The 2-year crude survival rates were 51.1% and 68.4% at high and low HGF concentrations, respectively. The results indicate that HGF is significantly increased in human esophageal SCCs, especially of poorly differentiated type. HGF might thus be useful as a biological biomarker for characterization of human esophageal SCCs.

Changes in immunoreactive insulin, C-peptide immunoreactivity, and immunoreactive glucagon in acute viral hepatitis

Insulin and glucagon are thought to play important roles as hepatotrophic factors in acute viral hepatitis (AVH); however, few reports have investigated the responses and relationships of each of these hormones to liver damage in detail. We studied insulin and glucagon responses during the acute and recovery phases of AVH. We performed a glucose tolerance test (GTT) and an insulin sensitivity test (IST) in each phase in 11 patients with AVH. In 8 additional patients in the acute phase (total n = 19), were compared immunoreactive insulin (IRI) and C-peptide immunoreactivity (CPR) levels with transaminase levels. In the acute phase, IRI concentrations were normal from fasting to 60 min, despite an increased CPR level. In the recovery phase, IRI and CPR levels increased significantly. Immunoreactive glucagon levels in both phases did not differ significantly from those in controls. During the IST, the insulin sensitivity index in both phases was significantly lower than that in the controls. Fasting IRI and sigma IRI showed significant negative correlations with transaminase levels. We found enhanced insulin secretion and a decrease in plasma insulin in the acute phase of AVH. The discrepancy between IRI and CPR responses in the acute phase suggests an increase in the degradation or consumption of insulin in the liver.

Concomitant expression of hepatocyte growth factor (HGF), HGF activator and c-met genes in human glioma cells in vitro

Three new cell lines of human glioblastoma have been established. These cells co-expressed hepatocyte growth factor (HGF) and its receptor, c-Met, genes in vitro. Reverse-transcriptase/polymerase-chain reaction study revealed that the cells also expressed gene for HGF activator, a recently cloned serine proteinase, suggesting that HGF might have a role in glioma cells in vitro as an autocrine factor. The activator mRNA was also detected in other well-established glioma cell lines, glioma tissues and normal brain. The concomitant expression of HGF, HGF activator and c-met was also detected in one glioblastoma case in vivo out of five tested.

Levels of hepatocyte growth factor in maternal serum and amniotic fluid

OBJECTIVE

The purpose of our study was to investigate hepatocyte growth factor levels in maternal serum and amniotic fluid during pregnancy. We also demonstrated production and secretion of hepatocyte growth factor by placenta and amnion at different stages of gestation.

STUDY DESIGN

Hepatocyte growth factor levels in maternal serum (n = 219), cord blood (n = 20), and amniotic fluid samples (n = 90) were measured by an enzyme-linked immunosorbent assay. The secretion of hepatocyte growth factor by placenta and amnion was evaluated by measuring the amount released into the culture supernatant.

RESULTS

Most hepatocyte growth factor levels in maternal serum were below the detection limit before 10 weeks of pregnancy. Levels increased significantly thereafter and continued to increase until term. On the other hand, levels in amniotic fluid were significantly higher between 20 and 29 weeks of gestation than after 30 weeks. Hepatocyte growth factor secretion from the placental tissue per weight seemed unchanged throughout pregnancy. Its secretion from amnion was, however, approximately 300 to 400-fold higher in the second trimester compared with that at term.

CONCLUSION

Both placenta and amnion produce and secrete hepatocyte growth factor, suggesting its role in fetal growth and the growth and differentiation of placenta.

Expression of hepatocyte growth factor receptor (c-met) mRNA in primary cultures of human hepatocytes

Aim-To investigate the regulation of hepatocyte growth factor (HGF) receptor (c-met) gene expression in isolated primary human hepatocytes.Methods-Primary hepatocytes were maintained in monolayer culture for up to 72 hours in serum-free medium. They were treated with growth factors and the level of HGF, c-met and reduced glyceraldehyde-phosphate dehydrogenase mRNA expression determined by northern blot analysis.Results-Hepatocytes expressed a single 9 kilobase c-met gene transcript whilst HGF mRNA analysis was negative. Addition of HGF and epidermal growth factor, both potent mitogens for human hepatocytes, enhanced c-met mRNA expression approximately twofold within 24 hours, after which levels returned to normal. In non-growth factor treated cells, transforming growth factor-beta (TGFbeta) had little effect upon c-met mRNA levels. However, TGFbeta inhibited the HGF induced increase in c-met mRNA levels.Conclusions-These results indicate that hepatocytes which proliferate in response to HGF demonstrate levels of c-met mRNA which are subject to growth factor modulation and suggest an important means of growth regulatory control.

Frequent expression of genes for receptor tyrosine kinases and their ligands in human pancreatic cancer cells

Limited information is available concerning the involvement of growth factor receptors and their ligands in the pathogenesis of human pancreatic cancer. We analyzed 12 human pancreatic cancer cell lines by Northern blot analysis for the expression of 9 receptor tyrosine kinase (RTKs) and 6 growth factors. The effect of a monoclonal antibody (MAb) against transforming growth factor-alpha (TGF-alpha) on in vitro pancreatic cancer cell growth was also assessed, mRNA for EGF-R, c-erbB-2 and c-erbB-3 was expressed in 12 (100%), 12 (100%), and 7 (58%), respectively, of the cell lines examined. In addition, 8 (67%) cell lines expressed the c-met/receptor for hepatocyte growth factor. As for ligands, TGF-alpha mRNA was detected in 10 (83%) cell lines; MAb against TGF-alpha inhibited growth of the 2 cell lines examined. Furthermore, mRNA for amphiregulin (AR) was expressed in 10 (83%) cell lines. Coexpression of TGF-alpha, AR, and EGF-R was observed in 9 (75%) cell lines. These results support the concept that several specified types of RTKs and their ligands are closely involved in regulation of the growth of human pancreatic cancer cells.

Effects of hepatocyte growth factor on viability and biotransformation functions of hepatocytes in gel entrapped and monolayer culture

OBJECTIVES

An extracorporeal bioartificial liver device must maintain viability and differentiated function of hepatocytes cultivated at high cell density. Growth factors, such as hepatocyte growth factor, found in high concentrations in the plasma of patients with fulminant hepatic failure, have the potential to promote hepatocyte dedifferentiation and thus, decrease function. We tested the hypothesis that hepatocyte growth factor would improve viable cell density and decrease biotransformation functions of liver cells in monolayer culture and in hepatocytes entrapped in collagen cylindrical gel "noodles" as found in the extracorporeal bioartificial liver.

DESIGN

In vitro, controlled study.

SETTING

University research laboratory.

SUBJECTS

Adult Sprague Dawley Rats.

INTERVENTIONS

Hepatocytes were harvested by a two-step collagenase technique. Harvested hepatocytes were plated onto type 1 collagen coated plates or entrapped in type 1 collagen cylindrical gels and cultured in different concentrations of hepatocyte growth factor. Interval measurements of 3H-thymidine incorporation, albumin synthesis, biotransformation functions, and viability were made.

MEASUREMENTS AND MAIN RESULTS

In monolayer culture, the addition of hepatocyte growth factor caused a dramatic increase in 3H-thymidine incorporation. This increase was accompanied by a decrease in the appearance of the lidocaine metabolite, monoethyglycinexylidide. Albumin production was unchanged. In cylindrical gel entrapment cultures, hepatocyte growth factor caused a significant increase in 2-day viability but had no effect on the metabolite appearance of lidocaine or 4-methyl umbelliferone or albumin production.

CONCLUSIONS

Hepatocyte growth factor induces dedifferentiation of hepatocytes in monolayer culture. Collagen matrix entrapment appears to abrogate this effect and improve liver cell viability. There may be reciprocal regulation of hepatocyte reproductive and differentiated functions, such as biotransformation, which can be influenced by the entrapment of hepatocytes in an extracellular type 1 collagen matrix.

Roles of hepatocyte growth factor and its receptor in gastric mucosa. A cell biological and molecular biological study

Hepatocyte growth factor (HGF) stimulates the growth of hepatocytes and other epithelial cells. A gene for the HGF receptor, c-met, is detected in the intestinal tract and the liver, as well as in gastric carcinoma cells. However, the role of HGF in the regeneration of the normal gastric mucosa is not known. The purpose of the present study was to elucidate the effects of HGF on the morphogenesis of cultured gastric mucosal cells and to evaluate the role of HGF and c-met in the healing process in rat gastric mucosa. The cultured gastric mucosal cells developed a branching morphology in a collagen matrix supplemented with HGF or fetal calf serum. They did not form this morphology on a plastic dish or in the collagen without HGF or the serum. In an in vivo study, total RNA was extracted from rat gastric mucosa 6, 24, 48, and 96 hr after the exposure to a solution of 0.6 M HCl. HGF messenger RNA was not detected, but c-met was expressed in the mucosa. The increased expression of c-met was followed by healing of the mucosal injury. These results indicate that HGF plays important roles in the morphogenesis of gastric mucosal cells and that the HGF receptor gene participates in the healing process of gastric mucosa.

Biological activation of pro-HGF (hepatocyte growth factor) by urokinase is controlled by a stoichiometric reaction

Hepatocyte growth factor (HGF) is a paracrine inducer of morphogenesis and invasive growth in epithelial and endothelial cells. HGF is secreted by mesenchymal cells as an inactive precursor (pro-HGF). The crucial step for HGF activation is the extracellular hydrolysis of the Arg494-Val495 bond, which converts pro-HGF into alpha beta-HGF, the high-affinity ligand for the Met receptor. We previously reported that the urokinase-type plasminogen activator (uPA) activates pro-HGF in vitro. We now show that this is a stoichiometric reaction, and provide evidence for its occurrence in tissue culture. Activation involves the formation of a stable complex between pro-HGF and uPA. This complex was isolated from the in vitro reaction of pure uPA with recombinant pro-HGF, as well as from the membrane of target cells, after sequential addition of uPA and pro-HGF. On the cell membrane, the uPA-HGF complex was bound to the Met receptor. Monocytic cell lines, and primary monocytes after adhesion, activated efficiently pro-HGF both on their surface and in the culture medium. This activation was inhibited by anti-catalytic anti-uPA antibodies, and occurred by a stoichiometric reaction. The stoichiometry of the activation reaction suggests that the biological effects of HGF can be titrated in vivo by the level of uPA activity. Adequate amounts of uPA can be locally provided by the macrophages, which would condition the tissue microenvironment by rendering HGF bioavailable to its target cells.

Characterization of the scatter factor/hepatocyte growth factor gene promoter. Positive and negative regulatory elements direct gene expression to mesenchymal cells

Scatter factor/hepatocyte growth factor (SF/HGF) and its receptor c-Met represent a paracrine signaling system involved in mesenchymal-epithelial interactions during development and during tumor progression. We have examined the promoters of the mouse and human SF/HGF genes by deletion mapping followed by CAT assays as well as by gel retardation and footprinting analysis. The promoter sequences are highly conserved (89.5% identity) up to position -453 from the major transcription start site but diverged considerably further upstream. Both promoters are active in mesenchymal but not epithelial cells thus reflecting the expression pattern of the SF/HGF gene in cells in vitro and in vivo. We have here identified two regulatory sequences in the SF/HGF promoter: a negative element at positions -239 to -258 and a positive element near the major transcription start site; specific deletions destroyed the activities of these elements. We were not able to localize elements on the SF/HGF promoter region that mediate the previously described effects of transforming growth factor beta, 12-O-tetradecanoylphorbol-13-acetate, and coculture of epithelial cells on SF/HGF gene expression. This study represents a first step toward understanding the intricately regulated and cell type-specific expression of the paracrine acting SF/HGF.

Serum hepatocyte growth factor levels in liver diseases: clinical implications

Although recent studies have shown that hepatocyte growth factor (HGF) is a potent mitogen in vivo, the significance of serum HGF in liver diseases remains unclear. To clarify clinical significance of serum HGF in liver diseases, serum HGF was measured in 127 patients with liver diseases and in 200 healthy individuals, using a highly sensitive immunoradiometric assay (IRMA). This assay is specific for HGF and is sensitive enough to detect 0.1 ng/mL of HGF. Mean values for serum HGF in acute hepatitis (AH), chronic hepatitis (CH), liver cirrhosis (LC), hepatocellular carcinoma (HCC), primary biliary cirrhosis (PBC), fulminant hepatic failure (FHF), and normal controls were 0.45, 0.40, 1.05, 1.06, 0.44, 16.40, and 0.27 ng/mL, respectively. Serum HGF levels in these diseases were significantly increased compared with those in the controls (P < .001), and exhibited a positive correlation with total bilirubin, indocyanine green (ICG) test (R15), asparate aminotransferase (AST), and a negative correlation with albumin and prothrombin time (P < .001). Cirrhotic patients with modified Child class C had higher levels of serum HGF than those graded as modified Child class A or B (P < .001). In CH, serum HGF levels were significantly related to the histological activity index (HAI) score (P < .002). Seven patients with HCC who underwent transcatheter arterial embolization (TAE) exhibited a gradual increase in serum HGF levels up to day 4 after treatment; these higher levels were maintained until day 7, although AST reached a peak on day 2 and then decreased gradually.(ABSTRACT TRUNCATED AT 250 WORDS)

Differing distribution of hepatocyte growth factor-positive cells in the liver of LEC rats with acute hepatitis, chronic hepatitis and hepatoma

Using anti-rat hepatocyte growth factor (HGF) antibody, we investigated the distribution of HGF-positive cells in the liver tissues of LEC rats at various phases of liver diseases. During the phase of fulminant hepatitis, HGF-positive cells increased remarkably, and many of them were localized at the portal triads; these cells were identified from their shape as non-epithelial cells. A reduced number of HGF-positive cells was observed during the phase of chronic hepatitis, while no HGF-positive cells were seen in the tissue of cholangiofibrosis. During the phase of carcinoma, staining revealed that both the hepatocellular carcinoma cells and the non-epithelial cells in cancerous liver tissue were HGF-positive. These results suggest that, in LEC rats, HGF may play an important role in the regeneration of hepatocytes as well as in the development of hepatocellular carcinoma.

Induction of hepatocyte growth factor in human skin fibroblasts by epidermal growth factor, platelet-derived growth factor and fibroblast growth factor

Hepatocyte growth factor (HGF) is a potent mitogen for rat and human hepatocytes in primary culture and appears to be the physiological hepatotrophic factor that triggers or modulates liver regeneration. Regulation of HGF gene expression and the protein production in human skin fibroblasts was examined. Addition of epidermal growth factor (EGF), platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF), acidic fibroblast growth factor (aFGF) and transforming growth factor-alpha (TGF-alpha) to confluent cultures of the cells markedly stimulated HGF secretion from the cells. The stimulating effect of EGF, PDGF and bFGF was further investigated. The effect of all three growth factors was maximal at 3-30 ng/ml and was accompanied by an increase in HGF mRNA levels. The mRNA levels were not elevated at 5 h but were at 10 h or more after addition of EGF. The levels of HGF mRNA in fibroblasts treated with the optimal doses of EGF, PDGF, bFGF, aFGF and TGF-alpha for 24 h were 6, 4, 5, 4 and 5 times that of control cultures incubated in medium only, respectively. The growth factor-induced HGF mRNA expression and HGF secretion was inhibited by addition of TGF-beta 1 or dexamethasone. Pretreatment with a high dose of phorbol 12-myristate 13-acetate (PMA), which causes down-regulation in protein kinase C (PKC) activity and PMA-induced HGF secretion, did not reduce the effects of the growth factors on HGF mRNA expression and HGF secretion, but rather enhanced them.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of human neonatal serum on DNA synthesis in suckling and adult rat hepatocytes in primary culture

The effect of human neonatal serum on DNA synthesis in suckling and adult rat hepatocytes in primary culture was investigated to characterize growth regulating factors of the liver in neonates and to confirm whether the stimulatory factor is human hepatocyte growth factor (hHGF). Neonatal serum stimulated DNA synthesis of both adult and suckling rat hepatocytes. The stimulatory effect was dose-dependent up to 20% in volume. The molecular weight of the stimulatory substance in neonatal serum was between 12,500 and 25,000, as estimated by gel filtration. Its activity was stable after heating at 56 degrees C for 20 min, but was lost after heating at 90 degrees C for 30 s, and easily passed through S- or heparin-Sepharose columns. The concentration of hHGF quantified by ELISA was too low to stimulate DNA synthesis in vitro. Biological and biochemical properties of the growth stimulatory activity in neonatal serum differed from that of hHGF. The presence of other growth factors in human neonatal serum for suckling and adult hepatocytes was suggested.

Rapid induction of mRNAs for liver regeneration factor and insulin-like growth factor binding protein-1 in primary cultures of rat hepatocytes by hepatocyte growth factor and epidermal growth factor

Liver regeneration factor belongs to the leucine-zipper family of transcription factors. It was originally cloned and characterized through differential screening of a regenerating rat liver cDNA library. The mRNA for liver regeneration factor-1 is barely detectable in normal rat liver but is dramatically induced after two-thirds hepatectomy, with a peak 1 to 3 hr after surgery. The nature of the signaling molecule(s) for this rapid induction is not known. It has been suggested that the liver regeneration factor-1 protein product, through complex interactions with other transcription factors such as c-Jun and Jun-B, controls expression of genes that are required during the G1 phase of hepatic growth. Hepatocyte growth factor has been shown to be the most potent mitogen for hepatocytes in vitro and in vivo. Plasma levels of hepatocyte growth factor rapidly (within 30 min) increase after loss of hepatic parenchyma induced by partial hepatectomy or carbon tetrachloride treatment. It has been postulated that hepatocyte growth factor plays a crucial role in stimulating the hepatocyte to enter the cell cycle. In this communication, we report that addition of pure hepatocyte growth factor to primary cultures of rat hepatocytes in the absence of serum and insulin results in rapid and transient induction of liver regeneration factor-1 mRNA (more than 20-fold) with a peak of expression 1 hr after treatment. The levels of jun-B and c-fos mRNAs, which are also known to be induced during the early hours of liver regeneration, were also increased after treatment of isolated hepatocytes with hepatocyte growth factor.(ABSTRACT TRUNCATED AT 250 WORDS)

Circulating proinflammatory cytokines (IL-1 beta, TNF-alpha, and IL-6) and IL-1 receptor antagonist (IL-1Ra) in fulminant hepatic failure and acute hepatitis

Fulminant hepatic failure (FHF) is characterized by massive necroinflammation of the liver tissue and is associated with high mortality. Serum concentrations of IL-1 beta, tumour necrosis factor-alpha (TNF-alpha), IL-6 and IL-1 receptor antagonist (IL-1Ra) were measured in 30 patients with FHF and in 23 patients with acute hepatitis (AH) before start of treatment and in 23 healthy controls. Levels of all four molecules were increased significantly in FHF compared with AH, in which values were higher than in the healthy controls. High serum levels of IL-1 beta and a significantly reduced ratio of IL-1Ra to IL-1 beta (IL-1Ra/IL-1 beta) were observed in FHF patients who subsequently died compared with subjects who survived. TNF-alpha and IL-6 concentrations were correlated with levels of human hepatocyte growth factor (hHGF), an index of hepatocyte regeneration. Although serum cytokine levels varied considerably between patients within each group studied, it is suggested that the striking elevation in proinflammatory cytokine levels in FHF may reflect both the insufficiency of hepatitis virus elimination and a failure to control a vicious cytokine cascade leading to overwhelming hepatocyte destruction rather than regeneration. The high cytokine levels observed in these patients and the significantly elevated IL-1Ra/IL-1 beta ratio in FHF patients who survived compared with those who did not suggest the possible therapeutic use of cytokine antagonists for the control of this life-threatening disease.

Expression of hepatocyte growth factor mRNA, and c-met mRNA (hepatocyte growth factor receptor) in human liver tumours

We have quantified mRNA for the hepatocyte growth factor and its putative receptor the c-met proto-oncogene protein product, in a series of human primary and secondary liver tumours and adjacent non-neoplastic liver. In all hepatocellular cancers, hepatocyte growth factor 6 kb mRNA expression was less (mean 23.93% +/- 6.33% S.E.M. n = 7) in the tumours than in the adjacent normal liver. Both relative over- and under-expression of c-met transcripts were found in tumour tissue compared to non-neoplastic liver. Thus hepatocellular cancer tissue does not over-express mRNA for hepatocyte growth factor, though this growth factor might play a role in hyperproliferative states leading to liver cancer.

Production of hepatocyte growth factor by human haematopoietic cell lines

Hepatocyte growth factor (HGF) is a multi-functional molecule characterized as a mitogen, a motogen, a morphogen and a tumour suppressor. Little is known about cell types which produce HGF, so we analysed HGF production from cultured cell lines of haematopoietic cell lineage. A total of 138 human leukemia and virus-transformed cell lines were studied and the levels of HGF were measured by ELISA. A significant amount of HGF was detected in a variety of cell lines, including one T, four B, five non-T non-B, eight myeloid one erythroid and two EBV-transformed B cell lines. The amount of HGF spontaneously produced by three of the myeloid cell lines, KCL-22 (33.48 ng/ml), KG-1A (26.21 ng/ml), and KG-1 (18.81 ng/ml), is comparable to the amount produced by human embryonic lung fibroblast cells, known as high HGF-producers. Biological assays together with Western blot analyses verified that the immunoreactive HGF detected in the culture supernatant of haematopoietic cell lines had the same properties as authentic HGF. Moreover, HGF mRNA was detected in high HGF producers by Northern blot analysis. Our findings that lymphoid and myeloid cells function as a source of HGF may provide significant evidence for the involvement of haematopoietic cells in HGF-related morphogenesis and cell growth.

Serum collagen type IV for the assessment of fibrosis and resistance to interferon therapy in chronic hepatitis C

Sixty-nine patients with chronic hepatitis C (CH-C) were treated with interferon therapy, and serum collagen type IV (s-collagen IV) levels were measured by enzyme immunoassay to analyze the responsiveness to interferon therapy. Classified by the improved pattern of serum alanine aminotransferase levels after interferon administration, 23 patients were judged as sustained responders, 23 as transient responders, and 23 as non-responders. Fibrotic grades of the liver sample correlated statistically with the levels of s-collagen IV (P < 0.01). Pre-therapy s-collagen IV levels of sustained responders were significantly lower than those of the other responders, and only sustained responders showed a significant decrease of s-collagen IV levels after interferon therapy, in accordance with histologic improvement. Multivariate analysis showed that s-collagen IV and hepatitis C virus genotype were the most important factors affecting the response to interferon therapy of all variates. Thus, s-collagen IV is one of the most useful aids for the evaluation of liver fibrotic grade in CH-C and a potent predicting indicator for the responsiveness to interferon therapy.

Hepatocyte growth factor in transgenic mice: effects on hepatocyte growth, liver regeneration and gene expression

Attention has recently been focused on hepatocyte growth factor as a major candidate factor in liver regeneration because it is the most potent known mitogen for hepatocytes in vitro. However, hepatocyte growth factor also displays diverse activities in vitro as scatter factor, as an epithelial morphogen, as a pluripotent mitogen and as a growth inhibitor. Consequently, we developed transgenic mice that expressed hepatocyte growth factor under the control of albumin regulatory sequences to examine its in vivo role in hepatocyte growth. Hepatocytes of these mice expressed increased levels of hepatocyte growth factor as an autocrine growth factor. Hepatocyte growth factor was a potent stimulus for liver repair; the livers of hepatocyte growth factor-transgenic mice recovered completely in half the time needed for their normal siblings after partial hepatectomy. This transgenic model also enabled us to study the chronic effects of hepatocyte growth factor expression. During several months of observation, the labeling index of hepatocytes in albumin-hepatocyte growth factor mice was doubled, and liver DNA content was increased compared with that in wild-type mice. To identify intermediate signaling pathways for hepatocyte growth factor that might regulate this increased growth response, we examined transgenic mice for changes in expression of genes that are known to be regulated during liver regeneration. We found that levels of c-myc and c-jun mRNA were increased in the hepatocyte growth factor-transgenic mice. In additional experiments the increased c-myc expression was the consequence of increased transcription rates as seen in nuclear run-on and myc-CAT reporter gene experiments. We conclude that hepatocyte growth factor increases growth and repair processes when expressed for long periods in the liver and that c-myc and c-jun may be important intermediaries in the hepatocyte growth response caused by hepatocyte growth factor.

Immunohistochemistry with antibodies to hepatocyte growth factor and its receptor protein (c-MET) in human brain tissues

Hepatocyte growth factor (HGF) is a potent mitogen for mature hepatocytes, and also has multifunctional effects on some other cells in various organs. The human c-Met proto-oncogene product has recently been identified as its high-affinity receptor. We examined HGF-like and c-Met protein-like immunoreactivities in the brains of neurologically normal, lacunar stroke and Alzheimer disease (AD) cases. The HGF antibody stained only round cells in the capillaries and astrocytes in the white matter. Positive staining with the antibody to c-Met protein was seen in microglia, predominantly in the white matter. The possibility of interactions between astrocytes and microglia through HGF and its receptor is suggested.

Regulating factors of liver regeneration after hepatectomy

The factors regulating liver regeneration were studied by measuring changes in the liver volume and serum hepatocyte growth factor (HGF) levels after hepatectomy. Changes in the liver volumes were studied in 68 hepatectomized patients, including (A) hepatoma patients who had chronic hepatitis or liver cirrhosis (n = 44) and (B) metastatic liver cancer patients who had normal liver parenchyma (n = 24). The hepatic volume increased by 13.8% of the remnant hepatic volume in group A and by 49.1% in group B. The examined factors included the percentage of resected liver volume (%RLV) and the results of laboratory tests. Regression analysis showed that in group A, both %RLV (beta = 0.46) and the serum total bilirubin (T-Bil) level (beta = -0.33) correlated significantly with the extent of liver regeneration and that in group B, only %RLV (beta = 0.78) correlated significantly with the regeneration. Serum HGF levels after hepatectomy were studied in 21 hepatectomized patients, including 11 hepatoma patients and 10 patients with some types of metastatic liver cancer. Serum HGF levels increased significantly after surgery in all 21 patients. Regression analysis, however, showed that the change in HGF was related to liver cirrhosis (beta = 0.46) and to the maximal postoperative T-Bil level (beta = 0.51) but not to the extent of liver regeneration after hepatectomy. These results suggest that liver regeneration is regulated primarily by factors relating to the percentage of the resected liver parenchyma and that serum HGF levels do not directly relate to liver regeneration after surgery.

c-met mRNA overexpression in human hepatocellular carcinoma

This study was aimed at assessing the presence of c-met overexpression in human hepatocellular carcinoma and at determining whether this feature is associated with a definite clinical or pathological characteristic. Expression of c-met was determined by Northern-blot hybridization of a specific probe (human met proto-oncogene) in 18 tumoral and nontumoral liver samples obtained in 18 cirrhotic patients with hepatocellular carcinoma submitted to surgical treatment. Eight of the 18 hepatocellular carcinomas exhibited c-met overexpression, with an increase ranging between 2-fold and 10-fold when compared by densitometry with the surrounding liver. By contrast, in the remaining 10 cases c-met expression was almost identical to that of the surrounding nontumoral liver tissue. Overexpression of c-met was not related to either the age, sex, etiology or functional status of the underlying liver disease, or to the size of the tumor, to its differentiation degree or to the presence of pseudocapsule invasion and existence of additional neoplastic nodules. These data indicate that almost half of the human hepatocellular carcinomas exhibit c-met overexpression. Nevertheless, the biological relevance of this characteristic is not known.

Plasma hepatocyte growth factor and biliprotein levels and outcome in fulminant hepatic failure

Plasma levels of growth factors may be important in determining the extent of liver regeneration in patients with fulminant hepatic failure and in this study human hepatocyte growth factor and biliprotein (bilirubin covalently bound to albumin) were determined in patients with fulminant hepatic failure, mainly as a result of acetaminophen overdose. Admission values for plasma human hepatocyte growth factor were significantly raised, although with a wide range in acetaminophen-induced fulminant hepatic failure (median 7.4 ng/ml, range 0.45-48.4 ng/ml, n = 34) and in fulminant hepatic failure from other causes (3.8 ng/ml, 1.72-25.1 ng/ml, n = 9) as compared to normal subjects (0.24 ng/ml, 0-0.5 ng/ml, n = 30). Higher plasma human hepatocyte growth factor was observed in patients who died (10.1 ng/ml, 3.8-48.4 ng/ml, n = 19) than in those who survived (4.3 ng/ml, 0.45-25.1 ng/ml, n = 22, p < 0.02), which may reflect lack of hepatic clearance in the former group. The median plasma biliprotein on admission (13.2 mg/l, range 6.3-100.7 mg/l, n = 43) was significantly increased compared to normal subjects (1.3 mg/l, 0-4.1 mg/l, n = 7, p < 0.001) with no difference between patients who survived or died, although when plasma biliprotein results were expressed as a percentage of the total bilirubin, the values were slightly higher in survivors (median 14.4%, range 10.8-40.5%, n = 23) compared to those who died (12.1%, 7.7-20.9%, n = 20, p = 0.004).(ABSTRACT TRUNCATED AT 250 WORDS)

Immunohistochemical detection of hepatocyte growth factor/scatter factor in human cancerous and inflammatory lesions of various organs

Hepatocyte growth factor (HGF)/scatter factor (SF) is a multifunctional factor considered to be potentially involved in tissue regeneration, wound healing, embryogenesis, angiogenesis and cancer invasion. Here we examined immunohistochemically the distribution of HGF/SF in human tissues, including cancerous and inflammatory tissues, using anti-HGF antibody. HGF/SF accumulation was clearly detected in the extracellular matrix, particularly along the basement membrane, in cancerous and inflammatory tissues, but only a little was detected in normal tissues. HGF/SF is well known to have a strong affinity for heparin in vitro, and from the results of our immunohistochemical assay, we considered that HGF/SF was bound to heparin or heparan sulfate of the extracellular matrix and basement membrane. HGF/SF was well localized in cancerous and inflammatory lesions of human lung, liver and pancreas, and in apparently normal tissues of kidney, adrenal gland and pancreas obtained at autopsy. In lung, HGF/SF was localized along the basement membranes of cancer cell nests, in the extracellular matrix of the cancer cell surface, cancer stroma and tissues invaded by cancer, and the basement membranes of bronchial epithelium and capillary vessels in inflammatory stroma. Since HGF/SF makes some cancer cells more invasive in vitro, the accumulation of HGF/SF in cancerous tissue suggests that the invasiveness of some cancer cells may be increased by HGF/SF in vivo.

Hepatocyte growth factor/scatter factor, liver regeneration and cancer metastasis

Hepatocyte growth factor (HGF) is the most potent stimulator of hepatocyte growth and DNA synthesis identified; it is now known to be the same molecule as scatter factor, which increases the motility of a variety of cell types. HGF is becoming recognized as one of the most important factors in the regulation of liver regeneration after surgical resection or chemical damage. HGF is produced by several tissues, including neoplasms; it can therefore provide a stimulus for increased motility of malignant cells by both a paracrine and autocrine mechanism. The receptor for HGF has been identified as the product of the oncogene c-met, raising the possibility that this gene plays a key role in facilitating cellular invasion. HGF may therefore be important not only for liver cell growth but also in metastasis. This article summarizes the current position of research on HGF, and presents both clinical and scientific evidence that strongly implicates this factor in liver regeneration and cancer invasion and metastasis.

Expression of the hepatocyte growth factor receptor in the regenerating rat liver

The c-met oncogene product is a cell-surface receptor, which ligand is believed to be the hepatocyte growth factor. We studied the expression of c-met oncogene in the regenerating rat liver after either partial hepatectomy or CCl4-induced liver injury. Northern blot analysis showed that after partial hepatectomy the transcripts of c-met decreased at 8 h, reached the minimum at 36 h, and returned to the steady level on the seventh day. In contrast with the hepatectomized liver, the transcripts of c-met increased after CCl4 treatment. These observations suggest that c-met transcription may be regulated differently depending on regeneration signals.