Partial purification and characterization of hepatocyte growth factor from serum of hepatectomized rats

Elevated Serum Concentrations of Hepatocyte Growth Factor in Patients With Multiple Myeloma

Serum from 398 myeloma patients at diagnosis and serial samples from 29 patients were analysed for hepatocyte growth factor (HGF). HGF was elevated at diagnosis in 43% of myeloma patients compared with healthy controls (median 1.00 ng/mL and 0.44 ng/mL, respectively;P < .00001). In the group with elevated HGF levels 46% of the patients reached plateau phase, as compared with 60% of the patients with low HGF levels (P = .005), and the median survival time was 21 and 32 months, respectively (P = .002). In a univariate Cox regression analysis, HGF was a significant predictor of mortality (P = .02). In the subgroup of patients with β2-microglobulin levels less than or equal to 6 mg/L, high versus low HGF was a prognostic factor when a multivariate Cox regression analysis was performed. In serial samples HGF was higher at the time of diagnosis and relapse (median 0.57 ng/mL and 0.52 ng/mL, respectively; P = .0018) than at response (median 0.24 ng/mL, P = .008). We conclude that HGF may be a useful follow-up parameter in myeloma patients. Measurement of HGF may identify a group of patients with poor response to melphalan-prednisone treatment and short survival. HGF was a prognostic factor in patients with high levels of β2-microglobulin.

Perioperative continuous hepatocyte growth factor supply prevents postoperative liver failure in rats with liver cirrhosis

Insufficient regeneration and dysfunction of cirrhotic liver following partial hepatectomy often make the resection extremely vulnerable to postoperative liver failure, which frequently leads to multiple organ failure. Hepatocyte growth factor (HGF), first identified as the most potent mitogen for primary hepatocytes, not only stimulates hepatic regeneration but also accelerates liver function, improves fibrosis, and protects liver cells against injury. Therefore, we investigated the ability of a continuous supply of HGF to cirrhotic livers to prevent postoperative liver failure in rats. After liver cirrhosis was induced in 40 rats by the intraperitoneal injection of dimethylnitrosamine (DMN) for 4 weeks, fibroblasts genetically modified to secret rat HGF or control fibroblasts were implanted in the spleens of 20 syngenic rats per group to supply HGF continuously and directly to the cirrhotic livers. Two weeks after the implantation, all rats underwent a 30% hepatectomy. The HGF administration significantly improved liver fibrosis at the time of operation, attenuated the postoperative hepatic damage on histological examination, markedly accelerated the liver regeneration at 24 h after the hepatectomy. The blood chemical analysis indicated that HGF significantly suppressed postoperative liver failure. Most importantly, the HGF treatment significantly improved the survival rate of the rats at 48 h after the hepatectomy. The perioperative continuous supply of HGF from the spleen effectively prevented liver failure following resection of cirrhotic livers in rats.

Enhancement of intestinal adaptation by hepatocyte growth factor

BACKGROUND/PURPOSE

Hepatocyte growth factor (HGF) was originally shown to enhance hepatocyte DNA synthesis. Recently, the expression of HGF and its receptor (c-met) were observed in the intestinal tract. In a previous study, we demonstrated that HGF can increase normal rat intestinal epithelial mass and function in vivo. This study was designed to determine if HGF, given either systemically or luminally, can enhance intestinal epithelial mass and function beyond the normal adaptive response after massive small bowel resection.

METHODS

Twenty young adult male Sprague-Dawley rats underwent an 80% small bowel resection. Seven days after resection, systemic infusion (via the jugular vein) or luminal perfusion (via the jejunum) were performed using subcutaneously placed osmotic minipumps. The rats were divided into four groups: group 1, systemic saline, (control, n=5); group 2, systemic HGF at 150 microg/kg/d (n=5); group 3, luminal saline, (control, n=5); and group 4, luminal HGF at 75 microg/kg/d (n=5). After a 14-day infusion, [C14] galactose and [C14] glycine absorption (micromol/cm2 intestine), mucosal DNA content (microg/mg mucosa) and protein content (microg/mg mucosa) were measured in the remaining small intestine of each rat.

RESULTS

Systemic infusion of HGF increased galactose absorption 68% (P<.05), glycine absorption 57% (P<.05), DNA content 17% (P<.01), and protein content 57% (P<.01), when compared with the appropriate control. Luminal perfusion of HGF also increased galactose absorption 114% (P<.01), glycine absorption 126% (P<.01), DNA content 32% (P<.01), and protein content 45% (P<.01), when compared with the appropriate control.

CONCLUSIONS

These data demonstrate for the first time that HGF can significantly enhance intestinal epithelial cell function and mucosal mass beyond the normal adaptive response. Luminal administration appeared to produce a greater response when compared with systemic administration but was significant only for galactose absorption (P<.05). HGF may be clinically useful in patients with short bowel syndrome.

Elevated Serum Concentrations of Hepatocyte Growth Factor in Patients With Multiple Myeloma

Serum from 398 myeloma patients at diagnosis and serial samples from 29 patients were analysed for hepatocyte growth factor (HGF). HGF was elevated at diagnosis in 43% of myeloma patients compared with healthy controls (median 1.00 ng/mL and 0.44 ng/mL, respectively;P < .00001). In the group with elevated HGF levels 46% of the patients reached plateau phase, as compared with 60% of the patients with low HGF levels (P = .005), and the median survival time was 21 and 32 months, respectively (P = .002). In a univariate Cox regression analysis, HGF was a significant predictor of mortality (P = .02). In the subgroup of patients with β2-microglobulin levels less than or equal to 6 mg/L, high versus low HGF was a prognostic factor when a multivariate Cox regression analysis was performed. In serial samples HGF was higher at the time of diagnosis and relapse (median 0.57 ng/mL and 0.52 ng/mL, respectively; P = .0018) than at response (median 0.24 ng/mL, P = .008). We conclude that HGF may be a useful follow-up parameter in myeloma patients. Measurement of HGF may identify a group of patients with poor response to melphalan-prednisone treatment and short survival. HGF was a prognostic factor in patients with high levels of β2-microglobulin.

Effects of sho-saiko-to extract on fibrosis and regeneration of the liver in rats

Sho-saiko-to, one of the most widely used Chinese herbal preparations, has long been used for the treatment of chronic liver diseases. We have investigated its effect in retarding the process of liver fibrosis and accelerating liver regeneration, especially its effect on Ito cells that are thought to be deeply involved with liver fibrosis. Sho-saiko-to extract and its active constituents were orally administered to rats with dimethylnitrosamine-induced liver-injury. After treatment with sho-saiko-to extract hepatic function improved, histopathological results confirmed repair of liver tissue, and retinoid levels increased. On the other hand, when active constituents of sho-saiko-to extract were administered alone, liver retinoid levels remained low, implying that interaction among active constituents of the extract was suppressing Ito cell activation. When sho-saiko-to extract was administered to 70% hepatectomized normal and liver-injured rats, liver weight, the number of S-phase-cells and retinoid levels increased with time. However, these changes were different for normal and liver-injured rats, suggesting that the site of action of sho-saiko-to extract in regenerating liver is different for normal and liver-injured rats. These results show that sho-saiko-to extract was useful for suppressing the activation of Ito cells.

Hepatocyte growth factor up-regulates SGLT1 and GLUT5 gene expression after massive small bowel resection

BACKGROUND/PURPOSE

Hepatocyte growth factor (HGF), originally known to stimulate hepatocyte DNA synthesis, also has been shown to stimulate growth of intestinal epithelial cells in vitro. The authors recently demonstrated that HGF can dramatically increase substrate absorption beyond the normal adaptive response after massive small bowel resection in the rat. However, the mechanism for this enhanced substrate absorption is unknown. This study was designed to determine if up-regulation of gene expression by HGF of the Na+/glucose cotransporter SGLT1 and the facilitative glucose transporter GLUT5 is a possible mechanism of action.

METHODS

Young adult Sprague-Dawley rats underwent an 80% small bowel resection and jejunostomy tube placement. Seven days later, an osmotic minipump was connected to the subcutaneously placed jejunostomy tube. The rats were divided into two groups based on the contents in the minipumps: group 1, saline (control, n = 5); and group 2, HGF at 75 microg/kg/d (n = 5). After a 14-day infusion, biopsy specimens of the small bowel mucosa were obtained. After total RNA extraction, Northern blot analysis was performed with SGLT1 and GLUT5 cDNA probes. Auto radiographs were quantitated by image analysis.

RESULTS

SGLT1 mRNA levels were significantly up-regulated in the HGF-treated animals (121% increase, P<.01) when compared with the control. Up-regulation of GLUT5 mRNA levels was also seen in the HGF-treated animals (96% increase, P < .01).

CONCLUSIONS

These data, demonstrating that HGF upregulates intestine epithelial glucose transporter gene expression after massive small bowel resection, may elucidate a mechanism of action for the enhanced carbohydrate absorption after HGF administration. This growth factor may be useful for patients with short bowel syndrome.

Co-expression of hepatocyte growth factor and its receptor in human prostate cancer

Hepatocyte growth factor acts differently depending on the organs or tumours involved. It may be produced simultaneously with its receptor, c-Met, in several types of malignant tumour cells and may exercise an autocrine regulation. To analyse the effect of hepatocyte growth factor in human prostate cancer, we conducted immunohistochemistry, in situ hybridization and the reverse transcriptase polymerase chain reaction. The first two techniques revealed the growth factor in prostate cancer cells, and the polymerase chain reaction confirmed this expression. c-Met is expressed in prostate cancer cells, but not in interstitial cells. Hepatocyte growth factor is expressed in interstitial cells, especially in hormone-treated cancer tissue, indicating that the growth factor pathway changes with the hormonal status. Low-grade tumours expressed c-Met at the plasma membrane. Higher grade tumours tended to express it in the cytoplasm, suggesting that the role of c-Met as the hepatocyte growth factor receptor was blocked in higher grade tumours. The relationship between the growth factor and its receptor is thus influenced by hormonal status and differentiation in prostate cancer and is not explained simply in terms of autocrine or paracrine action.

Expression of the HGF/SF receptor, c-met, and its ligand in human colorectal cancers

The c-met proto-oncogene product is a receptor tyrosine kinase that mediates the effects of the multifunctional cytokine hepatocyte growth factor/scatter factor (HGF/SF). We have studied the expression of both the c-met receptor and HGF/SF at both the protein and message level in colorectal cancer tissues of varying disease stage. All of the tumors displayed an overexpression of the c-met mRNA compared to their normal tissue counterparts while 16 of 21 tissues (75%) displayed up-regulation of c-met protein. No HGF/SF mRNA or protein could be detected in either tissue type. Viable tumor cells extracted from cancer tissue exhibited increased motility in response to HGF/SF stimulation demonstrating that c-met was functionally active. No correlation between expression of c-met and tumor stage or degree of differentiation was observed. HGF/SF is known to be a potent stimulator of tumor cell motility and invasion, two cellular properties essential for the metastatic development of cancers. The overexpression of the HGF/SF receptor in colorectal cancers may result in an increased sensitivity to HGF/SF, which may confer an enhanced metastatic potential to the cancer cells within the tumor body.

HGF/NK4 is a specific antagonist for pleiotrophic actions of hepatocyte growth factor

We prepared a specific antagonist for hepatocyte growth factor (HGF) and designated it HGF/NK4. HGF/NK4 is composed of N-terminal 447 amino acids of the alpha-chain of HGF, thus contains the N-terminal hairpin domain and subsequent four kringle domains. HGF/NK4 competitively inhibited the specific binding of HGF to the receptor. Importantly, HGF/NK4 neither stimulated DNA synthesis of primary cultured rat hepatocytes (mitogenesis) nor induced cell scattering (motogenesis) and branching tubulogenesis (morphogenesis) of MDCK renal epithelial cells, however, HGF/NK4 almost completely inhibited the mitogenic, motogenic, and morphogenic activities of HGF. HGF/NK4 also suppressed tyrosine phosphorylation of the c-Met/HGF receptor induced by HGF. Apparently this is the first documentation of a specific antagonist which abrogates the mitogenic, motogenic, and morphogenic activities of HGF.

Simultaneous or delayed administration of hepatocyte growth factor equally represses the fibrotic changes in murine lung injury induced by bleomycin. A morphologic study

Hepatocyte growth factor (HGF) is a humoral mediator of epithelial-mesenchymal interactions, acting on a variety of epithelial cells as mitogen, motogen, and morphogen. Exogenous HGF acts as a hepatotrophic factor and a renotrophic factor during experimental injury. To investigate whether HGF has a pulmotrophic function, human recombinant HGF was administered to C57BL/6 mice with severe lung injury by bleomycin (BLM). Low dose simultaneous and continuous administration of HGF (50 micrograms/mouse/7 d) with BLM (100 mg/mouse/7 d) repressed fibrotic morphological changes at 2 and 4 wk. Ashcroft score showed a significant difference in lung fibrosis with and without HGF at 4 wk (3.7 +/- 0.4 versus 4.9 +/- 0.3, p < 0.05). Furthermore, either simultaneous or delayed administration of high dose HGF (280 micrograms/mouse/14 d) equally repressed fibrotic changes by BLM when examined at 4 wk (Ashcroft score: 2.6 +/- 0.4 and 2.4 +/- 0.2 versus 4.1 +/- 0.2, p < 0.01). Hydroxyproline content in the lungs was significantly lower in mice with either simultaneous or delayed administration of high dose HGF as compared to those administered BLM alone (121.8 +/- 8.1% and 113.2 +/- 6.2% versus 162.7 +/- 4.6%, p < 0.001). These findings indicate that exogenous HGF acts as a pulmotrophic factor in vivo and prevents the progression of BLM-induced lung injury when administered in either a simultaneous or delayed fashion. HGF may be a potent candidate to prevent or treat lung fibrosis.

Expression of c-met proto-oncogene in primary colorectal cancer and liver metastases

We have examined the expression of c-met mRNA in tissue from 27 colorectal cancers and ten liver metastases using the reverse transcriptase-polymerase chain reaction method. The expression of c-met mRNA in these tissues was quantified and the copy number of c-met mRNA to 10(8.0) copies of beta-actin mRNA was calculated. Mean copy numbers of c-met mRNA in cancer tissue and normal mucosa were 10(5.5) and 10(4.5) respectively. The c-met expression of cancer was significantly higher than that of normal mucosa (P < 0.0001). In 20 of 22 samples in which c-met expression of both tumor and corresponding normal tissue were examined, c-met was overexpressed in the cancer tissue. No correlation was found between c-met expression and the clinicopathologic background. The mean copy numbers of c-met mRNA in the tissue from the ten liver metastases and normal liver were 10(6.1) and 10(6.2) respectively. Although c-met expression in metastatic tissue was higher than that in the primary cancer tissue, the increase was not statistically significant. In three of four patients with synchronous liver metastases, c-met was overexpressed in the metastatic tissue compared with that in the corresponding primary cancer tissue. These results show that c-met is overexpressed in both primary colorectal cancer and liver metastases and suggest that c-met plays a role in the development of colorectal cancer liver metastases.

Functional characterization of domains contained in hepatocyte growth factor-like protein

To delineate the functional protein domains necessary for the biological activity of hepatocyte growth factor-like protein (HGFL), we created various site-directed and deletion mutated cDNAs coding for this protein. Wild-type and mutated versions of HGFL were produced after transfection of the corresponding cDNAs into tissue culture cells. The biological importance of the domains within HGFL was then examined by addition of recombinant wild-type or mutant forms of HGFL to assays aimed at elucidating regions involved in the stimulation of DNA synthesis, the induction of shape changes in macrophages, and the ability to stimulate cell scattering. Mutant proteins lacking the serine protease-like domain (light chain) were not biologically active in any of the assays tested and could not compete with wild-type HGFL in cell scattering experiments. These data, in addition to direct enzyme-linked immunosorbent assay analyses, suggest that the light chain may play an important role in the interaction of HGFL with its receptor, Ron. Elimination of the proposed protease cleavage site between the heavy and light chains (by mutation of Arg-483 to Glu) produced a protein with activity comparable to wild-type HGFL. Further studies with this mutated protein uncovered an additional proteolytic cleavage site that produces biologically active protein. Deletion of the various kringle domains or the amino-terminal hairpin loop had various effects in the multiple assays. These data suggest that the heavy chain may play a pivotal role in determining the functional aspects of HGFL.

Existence of two nonlinear elimination mechanisms for hepatocyte growth factor in rats

Nonlinearity in the overall elimination of hepatocyte growth factor (HGF) was examined in rats. After intravenous administration, the plasma clearance (CLplasma) of HGF exhibited a dose-dependent biphasic reduction with high- and low-affinity components. If we consider our previous finding that both receptor-mediated endocytosis (RME) and a low-affinity uptake mechanism, probably mediated by heparan sulfate proteoglycan (HSPG), in the liver are major HGF clearance mechanisms, it may be that saturation of CLplasma at lower and higher doses represents saturation of RME and HSPG-mediated uptake, respectively. At an HGF dose (1.46 nmol/kg), which completely saturates the high-affinity component, CLplasma was almost completely reduced when HGF was premixed with heparin. However, CLplasma was reduced by heparin to, at most, one-fifth that after HGF alone in a dose near the linear range (3.66 pmol/kg). Saturation of CLplasma for HGF premixed with heparin was monophasic and nonlinear only at the lowest HGF doses. In vitro, high-affinity binding of [35S]heparin to HGF was found, showing that one HGF molecule binds to the penta- or hexasaccharide unit. Because mitogenic activity of HGF has been reported in the presence of heparin, these results suggest that heparin mainly inhibits low-affinity HGF uptake by complexing with HGF, whereas its effect on RME is relatively minor.

Serum hepatocyte growth factor as a possible indicator of arteriosclerosis

OBJECTIVE

To investigate the possible involvement of hepatocyte growth factor in arteriosclerotic lesions, by studying the relationship between serum concentrations of hepatocyte growth factor and grades of retinal arteriosclerosis.

METHODS

We measured the blood pressure, body mass index, serum concentrations of total cholesterol, high-density lipoprotein cholesterol, triglycerides, creatinine, uric acid, total protein, aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, gamma-glutamyltranspeptidase, alkaline phosphatase, and hepatocyte growth factor, erythrocyte counts, hemoglobin concentration, and hematocrit levels of 112 adults. Serum concentrations of hepatocyte growth factor were measured by a specific enzyme-linked immunosorbent assay. For each subject, photographs of both optic fundi were taken, and the grade of arteriosclerotic changes in the retinal arteries was evaluated according to Scheie's classification.

RESULTS

Individuals with more advanced grades of arteriosclerotic changes had higher serum hepatocyte growth factor values (grade 0, 0.056 +/- 0.004 ng/ml, n = 86; grade 1, 0.132 +/- 0.026 ng/ml, n = 17, P < 0.01, versus grade 0; grade 2-3, 0.271 +/- 0.023 ng/ml, n = 9, P < 0.01, versus grades 0 and 1). The serum hepatocyte growth factor concentrations were also correlated significantly to the serum uric acid concentrations (r = 0.230, P = 0.015) and erythrocyte counts (r = 0.299, P = 0.001), but not to the systolic and diastolic blood pressures, and other physical and humoral parameters.

CONCLUSIONS

Serum hepatocyte growth factor levels are thought to indicate the presence or development of arteriosclerotic lesions and may be a useful biochemical parameter for estimating the development of systemic arteriosclerosis irrespective of blood pressure levels.

Hepatocyte growth factor facilitates cartilage repair. Full thickness articular cartilage defect studied in rabbit knees

Hepatocyte growth factor (HGF) is a multifunctional factor which promotes proliferation, motility and morphogenesis in epithelial cells. In addition, it has been found to play an important role in cartilage metabolism. To investigate articular cartilage repair using HGF in vivo, we injected HGF into rabbit knee joints, where 4 mm diameter osteochondral defects had been made, and observed the animals for 6 months. We found that HGF effectively repaired osteochondral defects. The repair process of the articular cartilage defects using HGF was shown to be much better than saline injection on all macroscopic and histologic examinations. Although the observation period in our study was short, HGF is one of the most promising candidates for repairing articular cartilage defects clinically.

Influence of luminal hepatocyte growth factor on small intestine mucosa in vivo

In 1984, a growth factor was identified that stimulated hepatocyte DNA synthesis. This growth factor, referred to as hepatocyte growth factor (HGF), has been shown to enhance growth of intestinal epithelial cells in vitro. Recently, we reported that HGF can increase absorption and intestinal mass when given systemically in an in vivo model. This study was designed to examine if luminally administrated HGF can stimulate intestinal epithelial cell mass and function. Twenty-five young adult Sprague-Dawley rats had catheters inserted into the small intestine and connected to subcutaneously placed osmotic minipumps. The rats were divided into five groups (n = 5 for each group) based on the contents in the osmotic pump: group 1 received normal saline (control); groups 2, 3, 4, and 5 received HGF in increasing doses of 30, 75, 150, and 300 microg/kg/day, respectively. Following a 14-day infusion, [14C]galactose and [14C]glycine absorption was measured in 10-cm segments of mid-small intestine using an in vivo closed-recirculation technique. Mucosal DNA content and protein content of the same small bowel segment were determined for each group. HGF significantly increased galactose absorption at doses of 75 (P < 0.01) and 150 (P < 0.05) microg/kg/day and glycine absorption at doses of 30 (P < 0.05) and 75 (P < 0.01) microg/kg/day. HGF significantly increased DNA content (P < 0.01) at each dose and protein content when given at 30 (P < 0.01) and 75 (P < 0.01) microg/kg/ day. These data demonstrate that luminal administration of HGF can increase intestinal epithelial cell mass and function in vivo. HGF may be clinically useful in patients with inadequate intestinal function.

Continuous hepatocyte growth factor supply prevents lipopolysaccharide-induced liver injury in rats

We present a rat model in which continuous supply of hepatocyte growth factor (HGF) prevents liver injury induced by carbon tetrachloride (CCl4) and E. coli 011:B4 lipopolysaccharide (LPS). Rat fibroblasts genetically modified to secrete rat HGF were implanted in syngenic rat spleen 7 days before administration of the hepatotoxins. Rats with HGF-secreting fibroblasts in the spleen showed a dramatic resistance to CCl4- and LPS-induced liver injury. In the LPS-induced liver injury model, blood chemical analysis revealed that the increase in serum glutamic oxalacetic transaminase level and the decrease in blood sugar level were remarkably suppressed in rats with HGF-secreting cells in the spleen. Most importantly, their survival rate was greatly improved compared to other control groups of rats. Thus our results indicate a new role of HGF in liver protection during endotoxemia and convey important clinical implications for developing new therapeutic modalities in the treatment of liver failure caused by endotoxemia.

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.

Hepatocyte growth factor enhances intestinal mucosal cell function and mass in vivo

Hepatocyte growth factor (HGF), originally known to stimulate hepatocyte DNA synthesis, recently has been shown to enhance growth of intestinal epithelial cells in vitro. However, there have been no studies on the effect of HGF on the function of intestinal epithelial cells in vivo. This study was designed to examine the effect of systemically administrated HGF on intestinal epithelial cell mass and function. Twenty young adult male Sprague-Dawley rats underwent placement of jugular venous catheters connected to subcutaneously placed osmotic minipumps. The rats were divided into four groups based on the contents in the osmotic pump: Group 1 (control, n = 5), normal saline; Group 2 (n = 5), HGF 75 microg/kg/d; Group 3 (n = 5), HGF 150 microg/kg/d; and Group 4 (n = 5), HGF 300 microg/kg/d. After a 14 day infusion, [C14] galactose and [C14] glycine absorption were measured in a 10-cm segment of mid small intestine using an in vivo closed-recirculation technique. Mucosal DNA content and protein content of the same small bowel segment were determined for each group. With all three doses, HGF significantly increased DNA content (P < .01) and protein content (P < .05). HGF also significantly increased galactose absorption (P < .01) with all three doses. Glycine absorption was increased with a dose of 75 (P < .05) and 150 microg/kg/d (P < .01), but not at a dose of 300 microg/kg/d. These data demonstrate that HGF can increase intestinal epithelial cell mass and function in vivo. HGF may be clinically useful in patients with short bowel syndrome.

Enhanced expression of hepatocyte growth factor/c-Met by myocardial ischemia and reperfusion in a rat model

BACKGROUND

Hepatocyte growth factor (HGF) is a multifunctional factor implicated in tissue regeneration, wound healing, and angiogenesis. Circulating HGF is reportedly elevated during the early stage of myocardial infarction. However, its precise effect on the heart is unknown. To evaluate the regulation of HGF in ischemically damaged myocardium, the production of HGF and its high-affinity receptor, c-Met, was studied in a rat model of myocardial ischemia and reperfusion.

METHODS AND RESULTS

The plasma concentration of HGF began to increase within 1 hour of reperfusion after 1 hour of ischemia. The peak level was reached at 3 hours after reperfusion. Northern blotting revealed that HGF mRNA expression in the heart was augmented threefold at 24 and 48 hours and remained elevated by twofold at 120 hours after the myocardium was reperfused. The signal for c-met, high-affinity HGF receptor mRNA, was also upregulated parallel to upregulation for HGF. In the kidney, liver, lung, and spleen, HGF mRNA was also maximally increased at 12 hours after reperfusion. However, c-met was not upregulated in these organs. Immunohistochemical studies disclosed that capillary endothelial and interstitial cells, including infiltrating macrophages, were intensely stained for HGF, whereas capillary endothelial cells in the reperfused myocardium were positive for c-Met.

CONCLUSIONS

This study is the first to show that myocardial ischemia and reperfusion induced HGF expression in various organs in vivo. These results indicate that HGF/c-Met plays a role in capillary endothelial cell regeneration in the ischemically injured heart.

Control of invasive growth by hepatocyte growth factor (HGF) and related scatter factors

Hepatocyte growth factor (HGF) is the prototype of a family of structurally related soluble molecules, named scatter factors (SFs). These control a complex genetic programme leading to cell-dissociation, migration in the extracellular matrix, growth, acquisition of polarity and tubule formation. This programme is pivotal during the embryonic development of epithelial and some mesodermal-derived tissues. In the adult HGF sustains cell survival and regeneration. A structurally related molecule, originally identified as macrophage stimulating protein (MSP), triggers the same complex genetic programme in epithelial and neural cells. The receptors for HGF and MSP are the tyrosine kinases encoded by the homologous genes MET and RON. As a distinctive feature, these receptors act via a two-phosphotyrosine docking site, capable of concomitant activation of multiple intracellular transducers and signalling pathways. In a number of malignant tumours, MET and RON constitutively sustain the genetic programme of scattering, leading to invasive growth and metastatic phenotype. Four MET-related receptors have been recently identified (the SEX protein family). These molecules are predominantly expressed during development and are likely to mediate repelling cues between cells of different type.

Interaction of c-myc with transforming growth factor alpha and hepatocyte growth factor in hepatocarcinogenesis

Double transgenic mice bearing fusion genes consisting of mouse albumin enhancer/promoter-mouse c-myc cDNA and mouse metallothionein 1 promoter-human TGF-alpha cDNA were generated to investigate the interaction of these genes in hepatic oncogenesis and to provide a general paradigm for characterizing the interaction of nuclear oncogenes and growth factors in tumorigenesis. Coexpression of c-myc and TGF-alpha as transgenes in the mouse liver resulted in a tremendous acceleration of neoplastic development in this organ as compared to expression of either of these transgenes alone. The two distinct cellular reactions that occurred in the liver of the double transgenic mice prior to the appearance of liver tumors were dysplastic and apoptotic changes in the existing hepatocytes followed by emergence of multiple focal lesions composed of both hyperplastic and dysplastic cell populations. These observations suggest that the interaction of c-myc and TGF-alpha, during development of hepatic neoplasia contributes to the selection and expansion of the preneoplastic cell populations which consequently increases the probability of malignant conversion. These studies have now been extended to examine the interaction of hepatocyte growth factor (HGF) with c-myc during hepatocarcinogenesis in the transgenic mouse model. While sustained overexpression of c-myc in the liver leads to cancer, coexpression of HGF and c-myc in the liver delayed the appearance of preneoplastic lesions and prevented malignant conversion. Similarly, tumor promotion by phenobarbital was completely inhibited in the c-myc/HGF double transgenic mice whereas phenobarbital was an effective tumor promoter in the c-myc single transgenic mice. The results indicate that HGF may function as a tumor suppressor during early stages of liver carcinogenesis, and suggest the possibility of therapeutic application for this cytokine. Furthermore, we show for the first time that interaction of c-myc with HGF or TGF-alpha results in profoundly different outcomes of the neoplastic process in the liver.

Activation of Met tyrosine kinase by hepatocyte growth factor is essential for internal organogenesis in Xenopus embryo

Hepatocyte growth factor (HGF) specifically activates Met tyrosine kinase receptor, leading to mitogenic, motogenic, and morphogenic responses in a wide variety of cells. To know a role of HGF in Xenopus embryogenesis, loss-of-function mutation was introduced by dominant expression of truncated tyrosine kinase-negative Met. When tyrosine kinase-negative Met mRNA was micro-injected into two-cell to eight-cell stages Xenopus embryos, the liver development was mostly impaired and structures of pronephros and the gut were grossly underdeveloped in the restricted, late stage of development. These results strongly suggest that functional coupling between HGF and Met is essential for the development of internal organs originated from primitive gut and possibly involved in embryonic skeletogenesis. Together with developmental abnormality in mice mutated with HGF or Met gene, essential role of HGF for liver development is highly conserved from amphibian to mammalian species.

Characterization of glycosaminoglycans in regenerating canine liver

BACKGROUND/AIMS

Liver regeneration after partial hepatectomy is accompanied by hepatocyte proliferation and alteration of the extracellular matrix. Glycosaminoglycans, which are components of the extracellular matrix, interact with other matrix components, and are related to hepatocyte growth. The aim of this study was to investigate the relationship between hepatocyte proliferation and changes in glycosaminoglycan.

METHODS

Hepatocyte proliferation and changes in glycosaminoglycan were investigated in dogs after 55% partial hepatectomy. Hepatocyte mitosis was investigated by immunohistochemistry using anti-proliferating cell nuclear antigen antibody. The amount of glycosaminoglycan was determined by the carbazole-sulfuric acid method. We used a new method for analysis of glycosaminoglycan chains, involving endo-beta-xylosidase digestion and fluorescence labelling, to investigate the components of glycosaminoglycan.

RESULTS

Hepatocyte mitosis was increased after hepatectomy, reaching a peak at postoperative day 7. The total amount of hepatic glycosaminoglycan reached a maximum at 1 to 2 weeks afer hepatectomy, and the ratio of the components showed a concomitant change, the amount of heparan sulfate increasing, and that of chondroitin sulfate/dermatan sulfate decreasing. Increased heparan sulfate has shorter chains at 1 to 2 weeks after hepatectomy.

CONCLUSIONS

These results suggest that the transient changes in heparan sulfate with a decreased chain length and chondroitin sulfate/dermatan sulfate and observed during liver regeneration are associated with hepatocyte proliferation.

Liver regeneration

Liver regeneration after the loss of hepatic tissue is a fundamental parameter of liver response to injury. Recognized as a phenomenon from mythological times, it is now defined as an orchestrated response induced by specific external stimuli and involving sequential changes in gene expression, growth factor production, and morphologic structure. Many growth factors and cytokines, most notably hepatocyte growth factor, epidermal growth factor, transforming growth factor-alpha, interleukin-6, tumor necrosis factor-alpha, insulin, and norepinephrine, appear to play important roles in this process. This review attempts to integrate the findings of the last three decades and looks toward clues as to the nature of the causes that trigger this fascinating organ and cellular response.

Modifications of the hepatocyte growth factor/c-met pathway by constitutive expression of transforming growth factor-alpha in rat liver epithelial cells

We have previously shown that rat liver epithelial cells (RLEC) transfected with and constitutively expressing transforming growth factor-alpha (TGF-alpha) have an enhanced mitogenic response to hepatocyte growth factor (HGF). In the study reported here, we examined tumor clones derived from the TGF-alpha transfectants with respect to mitogenic response to HGF. Tumor cell lines that expressed TGF-alpha responded to HGF with a greater increase in DNA synthesis than did the nontransfected parental RLEC (pRLEC). The tumor clones had also acquired a lower threshold for HGF response, which enabled them to undergo significant DNA synthesis at a low concentration of HGF that did not evoke a response in the pRLEC or TGF-alpha transfectants. We investigated the mechanisms by which TGF-alpha expression may influence the HGF/c-met pathway. We showed that most TGF-alpha transfectants and tumor cells displayed increases in c-met mRNA and protein, indicating that the enhanced HGF response may be due in part to an increase in the amount of receptor present. However, in all transfectants and tumor clones that constitutively expressed TGF-alpha, c-met was tyrosine phosphorylated in the absence of ligand (HGF) or other exogenous growth factors. These data suggest that induction of c-met mRNA and transactivation of c-met may be a sequela of the constitutive expression of TGF-alpha and that constitutive activation of the epidermal growth factor receptor pathway leads to phosphorylation and activation of c-met. These studies provide evidence for a novel mechanism of communication between epidermal growth factor receptor and c-met pathways that may partially explain the synergistic effects reported between TGF-alpha and HGF.

Hepatocyte Growth Factor Is Constitutively Produced by Human Bone Marrow Stromal Cells and Indirectly Promotes Hematopoiesis

Bone marrow (BM) stromal cells are required for normal hematopoiesis. A number of soluble factors secreted by these cells that mediate hematopoiesis have been characterized. However, the mechanism of hematopoiesis cannot be explained solely by these known factors, and the existence of other, still unknown stromal factors has been postulated. We showed that hepatocyte growth factor (HGF ) is one such cytokine produced by human BM stromal cells. BM stromal cells were shown to constitutively produce HGF and also to express the c-MET/HGF receptor. The production of HGF was enhanced by addition of heparin and phorbol ester. Dexamethasone and tumor growth factor-β (TGF-β) inhibited the production of HGF. Interleukin-1α (IL-1α) tumor necrosis factor-α (TNF-α), and N6,2′-o-dibutyryl-adenosine-3′:5′-cyclic monophosphate (dbc-AMP) showed no obvious influence on HGF production. Western blot analysis of HGF derived from BM stromal cells showed two bands at 85 and 28 kD corresponding to native and variant HGF, respectively. Addition of recombinant HGF significantly promoted the formation of burst-forming unit-erythroid (BFU-E) and colony-forming unit-granulocyte erythroid macrophage (CFU-GEM) by BM mononuclear cells in the presence of erythropoietin and granulocyte-macrophage colony-stimulating factor (GM-CSF ), but the formation of CFU-GM was not modified. However, HGF had no effects on colony formation by purified CD34+ cells. Within BM mononuclear cells, c-MET was expressed on a proportion of cells (CD34−, CD33+, CD13+, CD14+, and CD15+), but was not found on CD34+ cells. We conclude that HGF is constitutively produced by BM stromal cells and that it enhances hematopoiesis. In addition, expression of c-MET on the stromal cells suggests the presence of an autocrine mechanism, operating through HGF, among stromal cells.

Hepatocyte Growth Factor Is Constitutively Produced by Human Bone Marrow Stromal Cells and Indirectly Promotes Hematopoiesis

Bone marrow (BM) stromal cells are required for normal hematopoiesis. A number of soluble factors secreted by these cells that mediate hematopoiesis have been characterized. However, the mechanism of hematopoiesis cannot be explained solely by these known factors, and the existence of other, still unknown stromal factors has been postulated. We showed that hepatocyte growth factor (HGF ) is one such cytokine produced by human BM stromal cells. BM stromal cells were shown to constitutively produce HGF and also to express the c-MET/HGF receptor. The production of HGF was enhanced by addition of heparin and phorbol ester. Dexamethasone and tumor growth factor-β (TGF-β) inhibited the production of HGF. Interleukin-1α (IL-1α) tumor necrosis factor-α (TNF-α), and N6,2′-o-dibutyryl-adenosine-3′:5′-cyclic monophosphate (dbc-AMP) showed no obvious influence on HGF production. Western blot analysis of HGF derived from BM stromal cells showed two bands at 85 and 28 kD corresponding to native and variant HGF, respectively. Addition of recombinant HGF significantly promoted the formation of burst-forming unit-erythroid (BFU-E) and colony-forming unit-granulocyte erythroid macrophage (CFU-GEM) by BM mononuclear cells in the presence of erythropoietin and granulocyte-macrophage colony-stimulating factor (GM-CSF ), but the formation of CFU-GM was not modified. However, HGF had no effects on colony formation by purified CD34+ cells. Within BM mononuclear cells, c-MET was expressed on a proportion of cells (CD34−, CD33+, CD13+, CD14+, and CD15+), but was not found on CD34+ cells. We conclude that HGF is constitutively produced by BM stromal cells and that it enhances hematopoiesis. In addition, expression of c-MET on the stromal cells suggests the presence of an autocrine mechanism, operating through HGF, among stromal cells.

Increase in the circulating level of hepatocyte growth factor in gastric cancer patients

We measured serum concentrations of hapatocyte growth factor (HGF) in patients with gastric cancer and compared these with the histological findings and conventional tumour markers, including CEA, CA19-9 and CA125, for evaluation of the significance of serum HGF levels as a tumour marker. The HGF levels were measured by an enzyme-linked immunosorbent assay (ELISA) system. The average levels of serum HGF in 89 healthy control subjects, 104 patients with primary gastric cancer and 15 patients with recurrent gastric cancer were 0.31 +/- 0.11 ng ml(1), 0.42 +/- 0.50 ng ml(-1) and 0.92 +/- 0.39 ng ml(-1) respectively. The average level in patients with recurrent disease was significantly higher than in healthy control subjects and in primary cancer patients (P< 0.001 and P< 0.003 respectively). Of 104 patients with primary gastric cancer, 35 (33.7%) showed an aberrant increase in the circulating level of HGF. The increased HGF levels were significantly associated with the degrees of histological tumour invasion and venous invasion. Of 15 patients with recurrent gastric cancer, 14 (93.3%) showed an aberrant increase. No correlation was found between serum HGF levels and CEA levels, CA19-9 levels and CA125 levels. However, the rate of the aberrant increase in HGF levels was significantly higher than that of any other tumour markers, including CEA, CA19-9 and CA125, in primary gastric cancer patients. In conclusion, the circulating levels of HGF were elevated in approximately one-third of patients with primary gastric cancer, particularly in those with high grades of histological tumour invasion and venous invasion, and frequently in patients with distant metastases, suggesting that HGF might play important roles in the tumour progression of gastric cancer. Furthermore, serum HGF levels may be of value as a tumour marker in patients with gastric cancer.

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.

Partial purification and characterization of serum embryotrophic factor required for early postimplantation growth of rat embryos in culture

Serum embryotrophic factor (SEF) required for the growth of cultured postimplantation rat embryos was partially purified from rat serum. Rabbit serum was used as a basal medium for the embryo culture, and embryotrophic activity was measured as embryonic protein increase. For partial purification of SEF, the rat serum globulin fraction obtained by ultracentrifugation and (NH4)2SO4 precipitation was fractionated by gel filtration, diethylaminoethyl ion-exchange chromatography, and hydroxyapatite chromatography. Partially purified SEF was characterized by stability tests and affinity chromatography. SEF was inactivated by heat, acid, dithiothreitol reduction, or trypsin digestion. SEF bound to concanavalin A but not to heparin. These results indicated that SEF was an acid-labile acidic glycoprotein with disulphide bonds and no affinity for heparin. The M(r) of SEF was estimated to be about 180 x 10(3) by gel filtration. The specific activity (U/g protein) was increased about 25-fold with 9.4% recovery by the partial purification, when 1 U of SEF was defined as the amount giving 50% embryonic protein increase. By polyacrylamide gel electrophoresis, a protein most likely to be SEF was identified as a heterodimer composed of subunits of M(r) 116 x 10(3) and 62 x 10(3) linked by disulphide bonds, and was shown to be contained in the medium at micromolar concentrations. SEF appeared to be distinct from known protein embryotrophic factors, growth factors, or cytokines.

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.

Concomitant expression of hepatocyte growth factor/scatter factor and the receptor c-MET in human myeloma cell lines

Myeloma cell line supernatants were screened for their ability to inhibit the activity of transforming growth factor-beta (TGFbeta) in the mink lung cell (Mv-1-Lu) bioassay. Supernatant from the human myeloma cell line JJN-3 contained potent TGFbeta antagonistic activity. This activity was isolated and found to be associated with a 72-78-kDa glycoprotein. Specific polyclonal and monoclonal antibodies were generated toward the 72-78-kDa protein, and these antibodies precipitated the TGFbeta inhibitory activity from JJN-3 supernatant. Upon amino acid sequencing the protein appeared to be identical to hepatocyte growth factor (HGF), and some of the generated antibodies directly blocked the action of recombinant HGF in various assays. By HGF-specific polymerase chain reaction we demonstrated that HGF mRNA was expressed in five out of five tested myeloma cell lines. The level of HGF protein in supernatants showed great variation from >500 ng/ml in JJN-3 supernatant to a few ng/ml in the supernatants from other myeloma cell lines. The same five cell lines were also screened for expression the HGF receptor c-MET. Four of them expressed the receptor as shown by reverse transcriptase-polymerase chain reaction and Western blot. The receptor was shown to be constitutively phosphorylated in the human myeloma cell line JJN-3. This receptor could be dephosphorylated by anti-HGF antibodies, indicating the existence of an autocrine HGF loop in this cell line. We propose that HGF/c-MET may play a role in multiple myeloma.

Expression of c-met/HGF receptor in human non-small cell lung carcinomas in vitro and in vivo and its prognostic significance

The expression of c-met/HGF receptor was evaluated in non-small cell lung cancers (NSCLC) by western blot analysis of 11 established cell lines and 104 surgically resected tissues. All cancer cell lines (eight adenocarcinomas, two squamous cell carcinomas and a large cell carcinoma) showed strong c-met protein bands of 145 kDa and 170 kDa. Moreover, c-met protein was demonstrated in 34 (72.3%) of 47 surgically resected adenocarcinomas, 20 (38.5%) of 52 squamous cell carcinomas and 3 of 5 others, and the results were mostly confirmed immunohistochemically in formalin-fixed and paraffin-embedded tumors of the same case. Although squamous cell carcinomas showed relatively high c-met protein expression in established cell lines, more adenocarcinomas than squamous cell carcinomas showed c-met protein expression in the original cancers. Furthermore, two cell lines used in this study originated from primary cancers negative for c-met protein expression, suggesting that c-met protein expression might be influenced by cultivation. Furthermore, clinicopathological study revealed that NSCLC with c-met protein expression tended to be in a higher pathological tumor stage and to have a worse outcome than those without such expression. In conclusion, c-met protein is expressed in cell lines and primary tumors of NSCLC, and this phenomenon is probably closely related to the aggressive behavior or progression of NSCLC, especially of adenocarcinomas.

Hepatocyte growth factor and its actions in growth plate chondrocytes

Hepatocyte growth factor (HGF) has been implicated as a paracrine regulator of organogenesis and repair in many tissues. Here we have studied the expression and actions of HGF in intact rachitic rat growth plate and derived cultures of proliferative zone chondrocytes. In vivo and in vitro chondrocytes express HGF mRNA; 1,25(OH)2 has a three-fold maximal stimulatory effect, which can be blocked by H-7, an inhibitor of protein kinase C. Although HGF elaboration and action generally follow a paracrine model, chondrocytes appear capable of both expressing and responding to HGF. mRNA encoding the HGF receptor (c-met) was detected in both growth cartilage and derived chondrocyte cultures. HGF addition to chondrocyte cultures increased collagen II mRNA and alkaline phosphatase enzymatic activity to degrees comparable to that observed for active vitamin D metabolites. Combining HGF and 1,25-D evoked a synergistic response (ninefold) of alkaline phosphatase activity. To assess whether a similar stimulatory effect might be seen with bioactive peptides and HGF, we investigated the effect of HGF pretreatment on acute responses of chondrocytes to synthetic human calcitonin, an anabolic chondrocyte regulator whose skeletal action are mediated principally by cAMP elevation and subsequent protein kinase A activation. CT's maximal activation of protein kinase A was increased by prior HGF treatment from 56% to 78%. In concert, our findings indicate that in addition to HGF's classical paracrine role during skeletal growth, this growth factor may modulate hormonal sensitivity of the chondrocyte during proliferation, differentiation, and/or apoptosis.

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.

Hepatocyte growth factor. A cytokine mediating endothelial migration in inflammatory arthritis

OBJECTIVE

Angiogenesis is an integral component of the vasculoproliferative phase of rheumatoid arthritis (RA). Recently, a heparin-binding cytokine termed hepatocyte growth factor (HGF), or scatter factor (due to its ability to disperse cohesive epithelial colonies), was described. We conducted this study to investigate the hypothesis that this cytokine was present in the milieu of the inflamed joint, and that it contributed to the chemotaxis of endothelial cells in the synovial tissue.

METHODS

We examined synovial fluid, synovial tissue, and peripheral blood from 91 patients with RA and other arthritides. We used 83 total samples in an enzyme-linked immunosorbent assay to quantitate the HGF in synovial fluids and peripheral blood. To determine whether the HGF was biologically active, an epithelial scatter factor assay was performed. Immunohistochemical analysis was used to determine localization in synovial tissues. To define a function for synovial HGF, we preincubated rheumatoid synovial fluids with neutralizing anti-HGF and measured the ability of these synovial fluids to induce endothelial chemotaxis.

RESULTS

Synovial fluid from patients with RA contained a mean +/- SEM HGF concentration of 2.0 +/- 0.3 ng/ml, while synovial fluid from patients with other arthritides (including inflammatory arthritis) contained 2.4 +/- 0.7 ng/ml HGF. Osteoarthritis (OA) patient samples contained the smallest quantities of synovial fluid HGF at 0.9 +/- 0.1 ng/ml. RA synovial fluid contained significantly more HGF than did RA peripheral blood (1.1 +/- 0.2 ng/ml) (P < 0.05). Rheumatoid synovial fluids induced more scattering of cells than did OA synovial fluids, suggesting a role for this cytokine in rheumatoid joint destruction. Interleukin-1 beta induced expression of rheumatoid synovial tissue fibroblast antigenic HGF and scatter factor activity. Immunohistochemically, HGF, as well as the HGF receptor (the met gene product), localized to significantly more rheumatoid synovial tissue lining cells than normal lining cells (P < 0.05). Both HGF and its receptor immunolocalized to subsynovial macrophages as well. Levels of synovial tissue immunoreactive HGF correlated positively with the number of synovial tissue blood vessels. Anti-HGF neutralized a mean of 24% of the chemotactic activity for endothelial cells found in 10 rheumatoid synovial fluid samples.

CONCLUSION

These results indicate that synovial HGF may contribute to the vasculoproliferative phase of inflammatory arthritides such as RA, by inducing HGF-mediated synovial neovascularization. These findings point to a newly described role for HGF in the fibroproliferative phase of RA-associated synovitis.

Management of acute renal failure: new perspectives

Despite major developments in medicine, surgery, and intensive care, acute renal failure (ARF) still remains a common problem affecting approximately 5% of all general hospital patients. Mortality of all forms of ARF continues to be greater than 50%, and this percentage has not decreased significantly over the last 30 years. There are multiple factors, which may explain the persistence of such high mortality; the most important of these is probably the evolution of the disease spectrum underlying the development of ARF. At present, ARF is more often observed in older or more complex patients frequently in association with multiorgan system failure. The annual cost of managing ARF is staggering. This article reviews several of the new strategies and approaches that have been developed to aid in the management and prevention of ARF. For example, the use of biocompatible membranes has been proven to positively influence the course of ARF, which necessitates renal replacement therapy. Although continuous renal replacement therapy has a theoretical advantage compared with intermittent hemodialysis in critically ill and hemodynamically unstable patients, there are no well-controlled clinical studies to support a beneficial effect on mortality. There is, however, good evidence that calcium channel blockers play a positive role in the management of ARF, especially that associated with cadaveric kidney transplantation. Vasoactive agents, such as dopamine, may have the advantage of increasing the urine output in patients with oliguric ARF; however, their efficacy in otherwise altering the course of ARF is not well substantiated. Finally, growth factors and atrial natriuretic peptide appear to have the potential for accelerating renal recovery and decreasing morbidity and mortality from this commonly encountered medical problem. Prospective randomized clinical studies are the key to many of the dilemmas encountered with ARF.

Amelioration of disordered hepatic protein synthesis by the deleted form of hepatocyte growth factor in models of liver failure in rats

Because the liver plays an important role in protein synthesis and cholesterol metabolism and reductions in these functions are observed in almost all hepatic disorders, the effects of the deleted form of hepatocyte growth factor (dHGF) on disordered hepatic protein synthesis were studied in various liver-injured rat models using Wistar male rats. In the 70% hepatectomized rats, plasma clotting time was prolonged and the serum level of total protein and the liver protein content were decreased. The treatment of the animals with dHGF (100-500 micrograms kg-1, i.v., twice daily) ameliorated these parameters at 48 or 72 h. The administration of carbon tetrachloride or D-galactosamine to hepatectomized rats induced a marked prolongation of plasma clotting time and hypoproteinaemia. In the animals treated with dHGF (500 micrograms kg-1, i.v., twice daily) these parameters were rapidly reversed compared with those of control groups. In a hepatocellular necrosis model induced by dimethylnitrosamine, the plasma clotting time was extremely prolonged, and liver protein content, serum total protein, albumin, HDL-cholesterol (as an index of lipoprotein) and plasma lecithin-cholesterol acyltransferase activity severely reduced. In this severely injured model, dHGF (5-500 micrograms kg-1, i.v., twice daily for 28 days) dose-dependently prevented the loss of liver protein content and improved the disordered plasma coagulability and serum protein levels. These results suggest that dHGF is useful for ameliorating the disorders in hepatic functions such as protein synthesis.

Hepatocyte growth factor is a coupling factor for osteoclasts and osteoblasts in vitro

Hepatocyte growth factor (HGF), also known as scatter factor, is a powerful motogen, mitogen, and morphogen produced by cells of mesodermal origin, acting on epithelial and endothelial cells. Its receptor is the tyrosine kinase encoded by the c-MET protooncogene. We show that the HGF receptor is expressed by human primary osteoclasts, by osteoclast-like cell lines, and by osteoblasts. In both cell lineages, HGF stimulation triggers the receptor kinase activity and autophosphorylation. In osteoclasts, HGF receptor activation is followed by increase in intracellular Ca2+ concentration and by activation of the pp60c-Src kinase. HGF induces changes in osteoclast shape and stimulates chemotactic migration and DNA replication. Osteoblasts respond to HGF by entering the cell cycle, as indicated by stimulation of DNA synthesis. Interestingly, osteoclasts were found to synthesize and secrete biologically active HGF. These data strongly suggest the possibility of an autocrine regulation of the osteoclast by HGF and a paracrine regulation of the osteoblast by the HGF produced by the osteoclast.

Comitogenic effects of vasoactive intestinal polypeptide on rat hepatocytes

The primary mitogens such as epidermal growth factor and transforming growth factor-alpha are known to stimulate DNA synthesis in primary cultures of adult rat hepatocytes. Vasoactive intestinal polypeptide (VIP) was found to amplify DNA synthesis induced by the primary mitogens and thus acted as a comitogen. The comitogenic effect of VIP was specific for the culture medium, suggesting that minor components in the medium were required for hepatocytes to fully respond to VIP. Glutamic acid is probably one of these minor components, although other components present in the nutrient-rich medium were also necessary for the full comitogenic effect. Other comitogens such as insulin, vasopressin, and angiotensin II interacted additively with low concentrations of VIP. The comitogenic effect of VIP was also found in hepatocytes cultured from regenerating rat liver after a partial hepatectomy. In the regenerating hepatocyte cultures, VIP can act as a mitogen even in the absence of the primary mitogen EGF. VIP mRNA was found in several organs including brain, intestine, and liver, and its expression was slightly induced in liver 24 h after a partial hepatectomy. These results suggest that VIP can act as a hepatic comitogen and may play a role in liver cell proliferation.

Epidermal growth factor, but not hepatocyte growth factor, suppresses the apoptosis induced by transforming growth factor-beta in fetal hepatocytes in primary culture

We studied whether the TGF-beta-induced apoptosis in fetal hepatocyte primary cultures may be modulated by the presence of mitogenic stimuli, such as EGF or HGF. EGF prevented cell death, showing a dose dependence that was identical to that observed for its effect on DNA synthesis stimulation. HGF, in contrast, had no effect, even at high concentrations. EGF blocked apoptosis, since in the presence of this factor cells did not show DNA fragmentation. Moreover, EGF, but not HGF, blocked c-fos induction associated with the apoptotic process induced by TGF-beta in these cells.

Plasma hepatocyte growth factor levels are increased in systemic inflammatory response syndrome

Interleukin-1 (IL-1), a cytokine released from macrophages by endotoxin stimulation, has been shown to upregulate the genetic expression of the hepatocyte growth factor (HGF). The present study was conducted to determine whether plasma HGF is increased in patients with systemic inflammatory response syndrome (SIRS). The plasma levels of HGF, endotoxin, and beta-glucan were measured in 41 surgical patients without hepatic diseases, 18 of whom had been diagnosed with sepsis, and 33, with nonseptic SIRS. The plasma HGF was found to be significantly increased in the 18 patients with sepsis, at 0.69 +/- 0.47 ng/ml (mean +/- SD), and in the 23 patients with nonseptic SIRS, at 0.49 +/- 0.37 ng/ml, compared to values in 40 normal controls, at 0.10 +/- 0.03 ng/ml (P < 0.001). No significant correlations were observed between the plasma levels of HGF and endotoxin (r = 0.02) or beta-glucan (r = -0.05) in any of the patients; however, plasma HGF was significantly correlated with the WBC count (r = 0.34, P < 0.05) and with total bilirubin (r = 0.45, P < 0.01). Plasma HGF was also strongly correlated with alanine transaminase (ALT) in 8 patients with ALT levels higher than 50 U/l (r = 0.70), but there was no such correlation in 33 patients with ALT levels of 50 U/l or less (r = 0.30). Thus, although the clinicopathologic significance of HGF is not well understood, the present findings indicate that plasma HGF increases in response to infection or inflammation.

Hepatocyte growth factor is involved in the morphogenesis of tooth germ in murine molars

The patterns of gene expression for hepatocyte growth factor (HGF) and its receptor, c-Met, were revealed in the tooth germ of rat mandibular molars using RT-PCR. In situ hybridization demonstrated that the HGF gene was expressed only in the cells of the dental papilla of the tooth germ in vivo. The characteristic temporospatial distribution of HGF and c-Met during germ development was revealed using immunohistochemical studies in vivo. In order to demonstrate the functional role played by HGF in tooth development, HGF translation arrest by antisense phosphorothioate oligodeoxynucleotide (ODN) was carried out in vitro. In the control experiment, explants of tooth germs from embryonic 14 day mice were cultured in a modification of Trowell's system under serum-free and chemically defined conditions for two weeks. Other explants were cultured with 15mer antisense or sense ODN targeted to the HGF mRNA. Both the control and the sense-treated explants showed normal histological structure, as observed in vivo. On the other hand, antisense-treated explants exhibited an abnormal structure in which the enamel organs were surrounded by a thin layer of dentin and dental papilla, appearing ‘inside-out’ compared to the control and sense-treated explants, although the cytodifferentiation of ameloblasts and odontoblasts was not inhibited. The explants treated with recombinant human HGF combined with antisense ODN showed normal development, indicating that exogenous HGF rescued the explants from the abnormal structure caused by antisense ODN. The findings of a BrdU incorporation experiment suggested that the imbalance between the proliferation activity of the inner enamel epithelium and that of the dental papilla caused by HGF translation arrest results in the abnormal structure of the tooth germ. These results indicate that HGF is involved in the morphogenesis of the murine molar.

Quantitative analysis of vascular endothelial growth factor in primary breast cancer

BACKGROUND

Recent clinical studies have demonstrated that tumor angiogenesis is a potent prognostic indicator for breast cancer patients. The quantitation of endothelial growth factors is thought to be useful to assess angiogenic phenotype in the tumor. Among the many new endothelial growth factors, vascular endothelial growth factor (VEGF) is known to be particularly responsible for promoting the neovascularization in human breast cancer.

METHODS

Intratumoral protein levels of VEGF were measured by enzymatic immunoassay in 135 primary breast cancer tissues. The VEGF levels were compared with the microvessel density evaluated by immunostaining the endothelial antigen and also were compared with intratumoral protein levels of other endothelial growth factors, including basic fibroblast growth factor (bFGF) and hepatocyte growth factor (HGF).

RESULTS

Intratumoral VEGF concentrations varied from 3.3 pg/mg protein to 2032 pg/mg protein (average 148 pg/mg protein). An immunocytochemical analysis using anti-VEGF antibody confirmed that VEGF was located mainly in the cytoplasm of the tumor cells. The VEGF concentrations were significantly higher in vascularly rich tumors than in vascularly poor tumors. No significant association was found between VEGF concentrations and the two other endothelial growth factor concentrations.

CONCLUSIONS

The quantitation of intratumoral VFGF levels seems to be useful for assessing the activity of tumor angiogenesis.