- Email: [email protected]
853 PLATELET INFUSION THERAPY PROMOTES LIVER REGENERATION AFTER AN EXTENDED HEPATECTOMY IN RATS
04d: MOLECULAR AND CELLULAR BIOLOGY − d) LIVER REGENERATION
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promotion/inhibition genes associated with the G1/S (p21, CyclinA1, CyclinE) and G2/M (cyclinB1, Cdc25c) phase. Transcript and protein levels of Foxm1b, a transcription factor needed for hepatocyte proliferation, was down in c-Rel(−/−). Studies in c-Rel(−/−) and wildtype mice subjected to partial hepatectomy, confirmed these differences. Conclusions: NF-úB subunit c-Rel is a key component of the regenerative response in injured liver. Cell cycle promotion gene Foxm1b is a downstream target of c-Rel during the proliferation of hepatocytes following repeated liver injury and regeneration.
853 PLATELET INFUSION THERAPY PROMOTES LIVER REGENERATION AFTER AN EXTENDED HEPATECTOMY IN RATS
Figure 2. Ki-67 labeling index.
R. Matsuo1,2 , Y. Nakano1 , S. Murata1 , N. Ohkohchi1 . 1 Surgery, University of Tsukuba, Tsukuba, 2 Surgery, Ryugasaki Saiseikai Hospital, Ryugasaki, Japan E-mail: [email protected]
854 ALPHA-TAXILIN, A POSTULATED VESICLE TRAFFIC PROTEIN, MAY BE INVOLVED IN HEPATOCYTE PROLIFERATION
Background and Aims: In the last two decades, many attempts have been tried for liver regeneration therapy, but nothing is succeeded in clinical application. We recently reported platelets accumulate in the sinusoidal spaces and promote liver regeneration after an extended hepatectomy in mice. We also reported platelets promote hepatocyte proliferation via theAkt and the ERK1/2 pathways in vitro. We hypothesized that platelet could be applicable as liver regenerating factor after hepatectomy. The present study was designed to determine the applicability of platelet infusion therapy for liver regeneration. Materials and Methods: Seventy percent hepatectomy was carried out in male SD rats which were subsequently divided into two groups: (i) PRP group in which Platelet Rich Plasma (1×109 platelets/ml in normal saline) was infused via portal vein. (ii) NS group in which 1 ml of normal saline was infused via portal vein. Liver/body weight ratio of regenerating liver, Ki-67 labeling index, signal transduction relating to liver regeneration and laboratory data were analyzed. And the dynamics of platelets infused via portal vein were visualized before and after hepatectomy. Results: Both liver/body weight ratio and Ki-67 labeling index after 70% hepatectomy were significantly higher in the PRP group than that of the NS group (Figures 1, 2). The Akt pathway was activated more rapidly in the PRP group than in the NS group, and the activation of ERK1/2 pathway was prolonged in the PRP group than in the NS group. Many platelets accumulated in the sinusoidal spaces immediately after hepatectomy. Laboratory data did not reveal significant difference between each group. Conclusions: PRP infusion promotes liver regeneration after an extended hepatectomy in rats without any liver injury. Platelets infused via portal vein accumulated in the sinusoidal spaces immediately after hepatectomy without leading to thrombosis. PRP infusion can be applicable to liver regeneration therapy.
Figure 1. Liver/body weight ratio.
N. Ohtomo1 , T. Tomiya1 , Y. Tanoue1 , Y. Inoue1 , T. Nishikawa1 , N. Watanabe2 , H. Ikeda2 , M. Omata1 , Y. Seyama3 , N. Kokudo3 , J. Shibahara4 , M. Fukayama4 , H. Shirataki5 , K. Fujiwara6 . 1 Gastroenterology, University of Tokyo, 2 Clinical Laboratory, University of Tokyo Hospital, 3 Hepato-Biliary-Pancreatic Surgery, 4 Pathology, University of Tokyo, Tokyo, 5 Molecular and Cell Biology, Dokkyo University School of Medicine, Mibu, 6 Yokohama Rosai Hospital, Yokohama, Japan E-mail: [email protected] Background and Aims: Intracellular vesicle traffic is a principal transportation system in eukaryotic cells. It is considered to be involved in a variety of processes of cell proliferation. Recently, a novel protein named alpha-taxilin has been identified as a binding partner of the syntaxin family, which is a coordinator of intracellular vesicle traffic. However, the function of alpha-taxilin is not known. Recent studies have reported that alphataxilin is highly expressed in embryonic cells and in a kind of high-grade malignant cells. The aim of this study is to evaluate the involvement of alpha-taxilin in proliferation of normal hepatocytes and HCC cells. Methods and Results: In vitro experiments: Primary rat hepatocytes were seeded at low and high densities. Cellular contents of alpha-taxilin were gradually increased by culture in hepatocytes seeded at low density, but not in those at high density. Further increase was observed by addition of HGF only in low-density cultured hepatocytes, where DNA synthesis was markedly induced by HGF. In vivo experiments: Hepatic expressions of alpha-taxilin were examined in rats underwent two-thirds partial hepatectomy. The amount of alpha-taxilin expression began to increase at 2 hours after partial hepatectomy, peaked at 24 hours when hepatocyte proliferation was induced, and gradually decreased to pre-operative levels at 7 days. Immunohistochemistry showed strong staining of alpha-taxilin in hepatocytes in periportal areas at 24 hours, followed by a weak and diffuse staining at 48 hours. Relationship between the stainings of alpha-taxilin and proliferating cell nuclear antigen (PCNA), a marker of cell proliferation, was observed. Study in HCC patients: Surgically resected 29 nodules of HCC were studied. The expression of alpha-taxilin determined by immunohistochemistry was significantly correlated with PCNA-labeling index. It was also correlated with histological grade and invasive character of HCC. Much more weak and sporadic stainings of alpha-taxilin were found in the background liver of chronic hepatitis and cirrhosis, and were also correlated with PCNA stainings. Conclusions: Alpha-taxilin was expressed prior to DNA synthesis of hepatocytes. The expression of alpha-taxilin in HCC showed correlation with increased proliferative activity. These findings suggest that alphataxilin is involved in hepatocyte proliferation.
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promotion/inhibition genes associated with the G1/S (p21, CyclinA1, CyclinE) and G2/M (cyclinB1, Cdc25c) phase. Transcript and protein levels of Foxm1b, a transcription factor needed for hepatocyte proliferation, was down in c-Rel(−/−). Studies in c-Rel(−/−) and wildtype mice subjected to partial hepatectomy, confirmed these differences. Conclusions: NF-úB subunit c-Rel is a key component of the regenerative response in injured liver. Cell cycle promotion gene Foxm1b is a downstream target of c-Rel during the proliferation of hepatocytes following repeated liver injury and regeneration.
853 PLATELET INFUSION THERAPY PROMOTES LIVER REGENERATION AFTER AN EXTENDED HEPATECTOMY IN RATS
Figure 2. Ki-67 labeling index.
R. Matsuo1,2 , Y. Nakano1 , S. Murata1 , N. Ohkohchi1 . 1 Surgery, University of Tsukuba, Tsukuba, 2 Surgery, Ryugasaki Saiseikai Hospital, Ryugasaki, Japan E-mail: [email protected]
854 ALPHA-TAXILIN, A POSTULATED VESICLE TRAFFIC PROTEIN, MAY BE INVOLVED IN HEPATOCYTE PROLIFERATION
Background and Aims: In the last two decades, many attempts have been tried for liver regeneration therapy, but nothing is succeeded in clinical application. We recently reported platelets accumulate in the sinusoidal spaces and promote liver regeneration after an extended hepatectomy in mice. We also reported platelets promote hepatocyte proliferation via theAkt and the ERK1/2 pathways in vitro. We hypothesized that platelet could be applicable as liver regenerating factor after hepatectomy. The present study was designed to determine the applicability of platelet infusion therapy for liver regeneration. Materials and Methods: Seventy percent hepatectomy was carried out in male SD rats which were subsequently divided into two groups: (i) PRP group in which Platelet Rich Plasma (1×109 platelets/ml in normal saline) was infused via portal vein. (ii) NS group in which 1 ml of normal saline was infused via portal vein. Liver/body weight ratio of regenerating liver, Ki-67 labeling index, signal transduction relating to liver regeneration and laboratory data were analyzed. And the dynamics of platelets infused via portal vein were visualized before and after hepatectomy. Results: Both liver/body weight ratio and Ki-67 labeling index after 70% hepatectomy were significantly higher in the PRP group than that of the NS group (Figures 1, 2). The Akt pathway was activated more rapidly in the PRP group than in the NS group, and the activation of ERK1/2 pathway was prolonged in the PRP group than in the NS group. Many platelets accumulated in the sinusoidal spaces immediately after hepatectomy. Laboratory data did not reveal significant difference between each group. Conclusions: PRP infusion promotes liver regeneration after an extended hepatectomy in rats without any liver injury. Platelets infused via portal vein accumulated in the sinusoidal spaces immediately after hepatectomy without leading to thrombosis. PRP infusion can be applicable to liver regeneration therapy.
Figure 1. Liver/body weight ratio.
N. Ohtomo1 , T. Tomiya1 , Y. Tanoue1 , Y. Inoue1 , T. Nishikawa1 , N. Watanabe2 , H. Ikeda2 , M. Omata1 , Y. Seyama3 , N. Kokudo3 , J. Shibahara4 , M. Fukayama4 , H. Shirataki5 , K. Fujiwara6 . 1 Gastroenterology, University of Tokyo, 2 Clinical Laboratory, University of Tokyo Hospital, 3 Hepato-Biliary-Pancreatic Surgery, 4 Pathology, University of Tokyo, Tokyo, 5 Molecular and Cell Biology, Dokkyo University School of Medicine, Mibu, 6 Yokohama Rosai Hospital, Yokohama, Japan E-mail: [email protected] Background and Aims: Intracellular vesicle traffic is a principal transportation system in eukaryotic cells. It is considered to be involved in a variety of processes of cell proliferation. Recently, a novel protein named alpha-taxilin has been identified as a binding partner of the syntaxin family, which is a coordinator of intracellular vesicle traffic. However, the function of alpha-taxilin is not known. Recent studies have reported that alphataxilin is highly expressed in embryonic cells and in a kind of high-grade malignant cells. The aim of this study is to evaluate the involvement of alpha-taxilin in proliferation of normal hepatocytes and HCC cells. Methods and Results: In vitro experiments: Primary rat hepatocytes were seeded at low and high densities. Cellular contents of alpha-taxilin were gradually increased by culture in hepatocytes seeded at low density, but not in those at high density. Further increase was observed by addition of HGF only in low-density cultured hepatocytes, where DNA synthesis was markedly induced by HGF. In vivo experiments: Hepatic expressions of alpha-taxilin were examined in rats underwent two-thirds partial hepatectomy. The amount of alpha-taxilin expression began to increase at 2 hours after partial hepatectomy, peaked at 24 hours when hepatocyte proliferation was induced, and gradually decreased to pre-operative levels at 7 days. Immunohistochemistry showed strong staining of alpha-taxilin in hepatocytes in periportal areas at 24 hours, followed by a weak and diffuse staining at 48 hours. Relationship between the stainings of alpha-taxilin and proliferating cell nuclear antigen (PCNA), a marker of cell proliferation, was observed. Study in HCC patients: Surgically resected 29 nodules of HCC were studied. The expression of alpha-taxilin determined by immunohistochemistry was significantly correlated with PCNA-labeling index. It was also correlated with histological grade and invasive character of HCC. Much more weak and sporadic stainings of alpha-taxilin were found in the background liver of chronic hepatitis and cirrhosis, and were also correlated with PCNA stainings. Conclusions: Alpha-taxilin was expressed prior to DNA synthesis of hepatocytes. The expression of alpha-taxilin in HCC showed correlation with increased proliferative activity. These findings suggest that alphataxilin is involved in hepatocyte proliferation.