Seishu Tamaki

Therapeutic effects of restricted diet and exercise in obese patients with fatty liver

BACKGROUND/AIMS The incidence of obese patients with fatty liver has recently increased in Japan as well as in the United States and Europe. Fatty liver may occasionally progress to liver cirrhosis. In this study, we have compared the effects of restricted diet and exercise versus no treatment in obese patients with fatty liver. METHODS Twenty-five obese patients with fatty liver were divided into treated and control groups. Fifteen obese patients followed a program of restricted diet (ideal weight x 25 Cal x kg(-1)) and exercise (walking or jogging) for a trial period of 3 months. No changes in diet or lifestyle were made by the other 10 patients during the same trial period. Blood biochemical tests and liver histology were compared in all patients before and after the trial. RESULTS In the treated group, weight, blood biochemical data such as aminotransferase, albumin, cholinesterase, total cholesterol and fasting blood glucose values, and steatosis were significantly decreased after the trial. In the control group, there were no significant differences in the clinical and histological findings before and after the trial. CONCLUSIONS These results indicate that restricted diet and exercise therapy, such as walking and jogging, are useful means of improving blood biochemical data and histological findings in liver tissues related to fatty liver.

Serum hyaluronate reflects hepatic sinusoidal capillarization

BACKGROUND Most of circulating hyaluronate has been commonly degraded by hepatic sinusoidal endothelial cells (SECs). In hepatic sinusoidal capillarization, SECs morphologically change and also seem to decrease hyaluronate degradation. This work expands on the relationship between serum hyaluronate levels and changes in hepatic SECs accompanying hepatic sinusoidal capillarization. METHODS Serum hyaluronate levels were determined using an enzyme binding assay system. Liver biopsy specimens were collected to examine basement-membrane formation, the localization of Weibel-Palade bodies, and the localization of factor VIII-related antigen (FVIIIRAg) in SECs. RESULTS Serum hyaluronate levels increased with the progression of liver disorder, being high in all patients with liver cirrhosis. Patients showing markedly high serum hyaluronate levels, 200 ng/mL or more, had liver cirrhosis involving the SECs, which showed basement-membrane formation, Weibel-Palade bodies, and FVIIIRAg and closely resembled vascular endothelial cells. CONCLUSIONS Measurement of the serum hyaluronate concentration allows the evaluation of morphological and functional changes that occur in SEC accompanying hepatic sinusoidal capillarization in various liver disorders. The findings also suggest that patients with high serum hyaluronate levels, 200 ng/mL or more, have liver cirrhosis with typical hepatic sinusoidal capillarization formed by SECs containing FVIIIRAg.

Evaluation of hyaluronic acid binding ability of hepatic sinusoidal endothelial cells in rats with liver cirrhosis

BACKGROUND & AIMS In liver cirrhosis, the binding and degradation of hyaluronic acid in the hepatic sinusoidal endothelial cells are considered to be reduced by development of hepatic sinusoidal capillarization, resulting in high serum hyaluronic acid concentration. The aim of this study is to clarify the cause of high blood hyaluronic acid concentration in liver cirrhosis. METHODS Liver cirrhosis was induced in rats by thioacetamide administration. In vivo observation of sinusoidal capillarization, in vitro immunolocalization of factor VIII-related antigen and CD44, and [14C]hyaluronic acid binding in cultured sinusoidal endothelial cells were determined. RESULTS Basement membranes were observed on the basal side of sinusoidal endothelial cells. The fenestrae and fluorescent intensity of anti-CD44 bound to the cells decreased with progression of hepatic fibrosis. Immunofluorescent reactive products of factor VIII-related antigen were more abundant in the cirrhotic rats compared with the controls. Amount of [14C]hyaluronic acid binding was significantly decreased in the cirrhotic group compared with the controls. CONCLUSIONS One reason that the blood hyaluronic acid concentration increases markedly in liver cirrhosis is considered to be the reduction in hyaluronic acid receptors of hepatic sinusoidal endothelial cells and in the amount of hyaluronic acid binding to the cells.

Coordinated expression of integrin α6β1 and laminin in hepatocellular carcinoma

Abstract The interaction between tumor cells and laminin mediated by laminin-binding integrins is critical for tumor invasion and metastasis. The aim of this study was to clarify the altered expression of lamininbinding integrins with the change of laniinin deposition in hepatocellular carcinoma (HCC) in comparison with cirrhotic or normal liver by immunohistochemistry. In HCC, hepatoma cells and sinusoidal endothelial cells expressed integrins α1β1, α2β1, α3β1, and α6β1. Integrins α1β1 and α6β1 were detected in a continuous pattern along the sinusoids in accordance with laminin assembly. Integrins α2β1 and α3β1 were detected in a discontinuous pattern at these sites. Integrin α6β4 was not detected. In cirrhotic liver, although integrins α1β1 and α6β1 as well as laminin were detected in a continuous pattern along the sinusoids, integrins α2β1, α3β1, and α6β4 were not detected. In normal liver, although integrin α1β1 was detected in a continuous pattern along the sinusoids, neither integrins α2β1, α3β1, α6β1, α6β4, nor laminin were detected. We have clarified that, of laminin-binding integrins, the localization of integrin α6β1 shows the best correspondence with the localization of laminin. These results suggest that of laminin-binding integrins, integrin α6β1 is very important for cell-laminin interactions in HCC.

Significance of serum tissue inhibitor of metalloproteinases-1 in various liver diseases

BACKGROUND/AIMS This study was performed to assess the significance of elevated serum tissue inhibitor of metalloproteinases-1 concentration in various liver diseases. METHODS Tissue inhibitor of metalloproteinases-1 levels were measured in patients with various liver diseases, and were compared with serum type III procollagen-N-peptide (P III P), type IV collagen and laminin P1 levels, as well as with the histology of liver biopsy specimens. RESULTS Mean tissue inhibitor of metalloproteinases-1 levels were significantly higher in subjects with acute viral hepatitis, cirrhosis, alcoholic hepatitis, and alcoholic cirrhosis than in the control group (p < 0.05). Serum tissue inhibitor of metalloproteinases-1 levels in the various liver diseases showed positive correlation with serum type IV collagen, P III P, and laminin P1 levels. Regarding the relationship between tissue inhibitor of metalloproteinases-1 and liver histology, serum tissue inhibitor of metalloproteinases-1 levels correlated with the degree of hepatic fibrosis and inflammation, such as focal necrosis and cell infiltration. Furthermore, elevated serum tissue inhibitor of metalloproteinases-1 levels were especially related to the cell infiltration, focal necrosis, portal fibrosis, and serum type IV collagen level. CONCLUSIONS These findings suggest that the measurement of the serum tissue inhibitor of metalloproteinases-1 level in various liver diseases may be useful to estimate the active hepatic fibrogenesis associated with the active inflammatory stage of the liver injury.

Contraction and Relaxation of Ito Cells

Ito cells (hepatic stellate cells) are localized around liver sinusoidal endothelial cells. The cytoplasm of these cells contains contractile proteins such as actin and myosin, suggesting that microcirculation of liver sinusoids is regulated by the contraction and relaxation of these cells.

Hepatic Innervation and Hepatic Sinusoidal Cells

The innervation of the human liver is distributed throughout the hepatic lobules from the portal spaces to the centralobular spaces. Nerve endings in the intralobular spaces are localized mainly in the Disse spaces, and are closely related to hepatic stellate cells (HSCs). Various neurotransmitters such as substance P exist in these nerve endings. Substance P induces contraction in HSCs. In addition, HSCs possess endothelin (ET) receptors, and contract in response to ET-1 treatment. Moreover, α-smooth muscle actin (α-SMA) is localized in the cytoplasm of HSCs. α-SMA is closely related to the contractility of smooth muscle cells. Nitric oxide (NO) inhibits the contraction of HSCs. HSCs thus appear to be involved in the regulation of hepatic sinusoidal microcirculation by contraction and relaxation. In the human cirrhotic liver, intralobular innervation is decreased or absent, but ET, ET receptors, and NO are overexpressed in the HSCs. These phenomena indicate that HSCs in the human cirrhotic liver may play an important role in the sinusoidal microcirculation through agents such as ET or NO rather than through intralobular innervation.

Diagnosis and Treatment of Hepatic Fibrosis and Hepatic Sinusoidal Cells

Hepatic fibrosis is a common response to chronic liver injury from many causes, including alcohol, chronic viral infections, metabolic liver disorders, and autoimmune hepatitis. Hepatic fibrosis results from an imbalance in extracellular matrix (ECM) synthesis (fibrogenesis) and ECM degradation (fibrolysis). The dynamic process of hepatic fibrosis and the cells producing ECM or matrix metalloproteinases (MMP) have largely been elucidated; it is mainly hepatic stellate cells (HSCs) and Kupffer cells which are involved in fibrogenesis and fibrolysis, respectively. Based on an understanding of connective tissue metabolism, new perspectives for specific antifibrotic therapy in hepatic fibrosis are been developed. The new potential strategies for this therapy are the inhibition of ECM synthesis, augmentation of ECM degradation, inhibition of HSC activation, neutralization of proliferative or fibrogenic mediators, and gene therapy. These approaches are expected to prevent progressive hepatic fibrosis and cirrhosis in the future.

Fungus thielavia minor blocks hepatic stellate cell proliferation and inhibits experemental hepatic fibrosis in rats

Introdnction and Aim: Hepatic stellate cells (HSCs) are proliferated by cytokines such as PDGF and produce extracellular matrix (ECM) in response to TGF[3 1 in hepatic fibrosis. On the other hand, Fungus thielavia minor (OPC15161) inhibits mesangial cell proliferation and ECM production by the ceils, which are the principal cells producing ECM in the kidney. In this study, we examined the inhibitory effects of OPC-15161 against the HSC proliferation and ECM production in vitro, and against the rat thioacetamide (TAA)-induced hepatic fibrosis in vivo. Methods: In vitro: HSCs were isolated from Wistar rats by the collagenase perfusion method using an elutriation rotor and cultured for 24 hours. To determine the inhibitory effect of OPC-15161 on proliferation and ECM production, the uptake of 3H-thymidine and the production of 3H-hydroxyproline were compared in the presence of PDGF (10ng/ml) and TGFI~ 1 (lng/ml) and various concentrations (0-30 la g/ml) of OPC-15161. The changes of inocitol-triphosphate ( IP3) concentration and Ca 2÷ mobilization in HSCs with OPC-15161 were examined with an IP.~-assay system kit and by confocal scanning laser microscopy using Fluo-3AM, respectively. In vivo: TAA (200mg/kg) was injected intrapertioneally into rats for 12 weeks. Animals were given a diet containing OPC-15161 (group I) or standard diet (group I1) from 9 to 12 weeks. The degree of hepatic fibrosis, the mRNA expression by Northern blotting and the immunolocalization of type I procollagen were evaluated between group I and group II. In addition, the detection of HSCs in liver tissues of groups I and II was performed by immunohistochemistry (ABC methods) using anti-desmin antibody as a primary antibody. Results and Conclusion: 3H-thymidine uptake and the amount of 3H-hydroxyproline in cultured HSCs were significantly increased by PDGF and TGF13 1, but decreased dose-dependently by OPC-15161. The intracellular IP 3 and Ca 2÷ levels were increased by PDGF, but were suppressed by OPC-15161. In the rat TAA hepatic fibrosis model, the deposition of ECM and the expression of type I procollagen and desmin in the liver were significantly suppressed by OPC-15161. These results indicate that OPC-15161 blocks HSC proliferation through the IP3-Ca2* system and inhibits the process of the hepatic fibrosis in rats.