Kooko Sakakibara

Native collagen formation by liver parenchymal cells in culture

IN normal supporting tissue and repair tissue of animals collagen is usually considered to be produced by cells of mesenchymal origin. Little is known, however, about the type of cell which synthesises collagen in organs which undergo diffuse fibrosis without known physical trauma, such as in cirrhosis of the liver. Tissue culture has shown, however, that epithelial cells1, including cancer cells2 and smooth muscle cells3, can synthesise collagen. We report here that an epithelial clone, originating from the liver cell line of rat forms a considerable amount of native collagen in culture.

Collagen fiber formation as a common property of epithelial liver cell lines in culture.

Abstract Collagen fiber formation in vitro was morphologically investigated on 22 epithelial-like cell lines originating from normal rat livers mainly by using specific histochemical stainings. All the cell lines, eight of which were cloned formed typical “collagenous” and/or “reticulin” fibers in the histological sense when they had been left as a full sheet for more than 3 weeks without subculture. Only one of five fibroblastic cell lines serving as control formed fibers to a lesser degree. Different patterns were recognized in fibers appearing between the liver cell cultures and the fibroblast cultures.

Immunolocalization of type III collagen and procollagen in cirrhotic human liver using monoclonal antibodies

Immunolocalization of type III collagen and procollagen in cirrhotic human liver was studied using monoclonal antibody specific for the helical determinant of type III collagen extracted from human placenta. Deparaffinized, trypsin-treated cirrhotic liver sections from 8 autopsy cases were examined by the unlabeled peroxidase-antiperoxidase and immunofluorescence techniques. These techniques revealed the localization of this epitope shared by type III collagen and procollagen not only in the extracellular matrix of hepatocytes and sinusoidal cells but also in the cytoplasm. In hepatocellular carcinoma concurrent with cirrhosis, neoplastic cells were shown to react with this antibody as well. These results are consistent with data obtained using antiserum specific for bovine type III procollagen aminopeptide which appeared in our previous report.

Localization of type III procollagen aminopeptide antigenicity in hepatocytes from cirrhotic human liver

Immunolocalization of type III procollagen (pro III) in normal and cirrhotic human liver was studied using rabbit antiserum specific for bovine type III procollagen aminopeptide. The material examined was deparaffinized, trypsin-treated hepatic tissue sections from 28 autopsy cases, including 19 cirrhotic and 9 normal liver donors. Immunostaining, performed by the unlabeled peroxidase-antiperoxidase antibody technique demonstrated that extracellular matrices corresponding to perisinusoidal reticulin, collagen in periportal areas, and blood vessel walls were the common sites of pro III antigenicity in both normal and cirrhotic liver. Moreover, in the cirrhotic liver, the fibrous septa of pseudolobules, and cytoplasm of hepatocytes and sinusoidal cells were positive when stained for pro III peptide. The differential counts of pro III positive cells in cirrhotic liver, however, revealed that the average ratio of these hepatocytes to sinusoidal cells was 25 to 1, indicating complete dominance of hepatocytes with respect to stainability for pro III peptide compared to sinusoidal cells. In hepatocellular carcinomas co-existing with cirrhosis, neoplastic cells also displayed pro III antigenicity. These data suggest that hepatocytes of cirrhotic liver and hepatocellular carcinoma cells play a significant role in type III collagen synthesis in vivo.

High incidence of rat mammary carcinoma by oral administration of ethyl methanesulphonate

Ethyl methanesulphonate (EMS), one of the alkylating agents, is known to be a potent mutagen. We tested EMS for its carcinogenicity in female rats by oral administration. EMS was dissolved in drinking tap water at a concentration of 10(-3) M and was given for the first 12 weeks. The subcutaneous tumors were noticed as early as 16 weeks after initiating the experiment. At the 32nd week, all the surviving rats produced tumors; the majority were multiple tumors in the neck, axillar and inguinal areas corresponding to bilateral mammary glands. Histologically, the prevailing feature of the tumors was infiltrating medullary adenocarcinoma consistent with carcinoma of mammary duct origin. Neither regional lymph node involvement nor distant metastases were shown, but intraductal spread of carcinoma was a marked finding during the 32-week period.

Immunohistochemical localization fo galactocerebroside in kidney, liver, and lung of golden hamster

Localization of galactocerebroside in kidney, liver, and lung of hamster was studied by the immunoperoxidase method using an affinity-purified specific antibody. Epithelial cells of the following anatomical sites were labelled with the antibody: distal tubuli, ascending limbs of Henles loops, and collecting tubuli in kidney; periportal bile ducts and hepatic parenchyma in liver; bronchioli and alveoli in lung. The existence of galactocerebroside in these 3 organs was also confirmed by chemical analysis.