肝窦内皮细胞及其对肝细胞的影响

本文简要地介绍了SEC的结构、功能特点及其在肝病发生、发展过程中的作用。SEC对肝细胞既有保护作用,在一定条件下又参与肝细胞的损伤过程。SEC主要经自身数量、体积变化和分泌、吞噬功能的改变来参与肝脏的各种生理、病理变化。     

肝窦内皮细胞及其对肝细胞的影响

本文简要地介绍了ＳＥＣ的结构，功能特点及其在肝病发生，发展过程中的作用。ＳＥＣ对肝细胞既有保护作用，在一定条件下又参与肝细胞的损伤过程。ＳＥＣ主要经自身数量，体积变化和分泌，吞噬功能的改变来参与肝脏的各种生理，病理变化。     

剪切力对肝脏切除术后肝窦内皮细胞的作用

肝切除术是肝脏疾病尤其是肝脏肿瘤的重要治疗手段,并且在肝切除术后会出现肝脏血流动力学的改变.肝窦内皮细胞是肝窦毛细血管内一类特殊的内皮细胞,对血流变化十分敏感.本文就肝脏切除术后血流产生的剪切力作用于肝窦内皮细胞,从而调节肝细胞再生和肝组织恢复的作用及机制作一综述.     

肝部分切除术后P13K/Akt信号途径对肝窦内皮细胞功能的影响

肝窦内皮细胞(HSEC)在一定条件下可以释放多种介质, 如:肝细胞生长因子(HGF),转化生长因子β(TGF β),白细胞介素-6(IL-6),一氧化氮(NO)及一氧化氮合酶(NOS) 等,这些细胞因子和介质在肝再生中发挥重要的作用。PI3K/ Akt信号途径在细胞增殖、细胞周期及生存中起到重要作用,     

肝部分切除术后PI3K/Akt信号途径对肝窦内皮细胞功能的影响

肝窦内皮细胞（HSEC）在一定条件下可以释放多种介质，如：肝细胞生长因子（HGF），转化生长因子β（TGFβ），白细胞介素-6（IL-6），一氧化氮（NO）及一氧化氮合酶（NOS）等，这些细胞因子和介质在肝再生中发挥重要的作用。PI3K/Akt信号途径在细胞增殖、细胞周期及生存中起到重要作用，Akt酶是PI3K下游直接靶蛋白，     

乙醇对大鼠肝窦内皮细胞窗孔的影响

目的 研究慢性乙醇摄取对大鼠肝窦内皮细胞(LSEC)窗孔的影响。方法 用乙醇直接灌胃的方法建立大鼠酒精性肝病动物模型，并于开始灌胃4周末、8周末、12周末，以及停止灌酒后(用平衡饲料继续喂养)12周末，分别处死实验组及对照组动物，经心脏灌流后取肝脏组织行HE染色和透射电镜观察LSEC窗孔的动态变化。结果 正常的LSEC扁平，胞核及细胞器排列规则，远侧胞质呈薄片状，有许多窗孔，内皮下缺乏基底膜(BM)；乙醇喂养4周末，可见部分LSEC远侧胞窗孔数减少，但BM未形成；8周末，窗孔数明显减少或消失，内皮下开始有不完全的BM形成，同时有功能活跃的纤维母细胞形成；12周末进一步加重，甚至可见完整的BM形成，但这种改变也多限于单个或邻近的窦状隙内，极少有广泛的纤维化形成；停药12周末，失窗孔及内皮下BM形成明显减轻。结论 随着乙醇的慢性刺激LSEC的去窗孔化和BM的形成也逐渐发生，严重时可形成肝窦毛细血管化和肝纤维化；这种早期即有局限性的去窗孔化改变和毛细血管化的生成可能是形成酒精性周围型纤维化的基础；去除病因后这种肝纤维化是可逆的。     

肝移植大鼠肝窦内皮细胞细胞凋亡与移植肝肝细胞损害的关系

目的探讨冷保存肝移植大鼠肝窦内皮细胞（SEC）细胞凋亡与移植肝肝细胞损害的关系。方法雄性SD大鼠随机分为假手术组（n=6）、UW1h肝移植组（11=48）、UW12h肝移植组（n=48）。参照Kamada的方法行原位肝移植（OLT）。观察大鼠I68h存活率。分别于术后不同时相点采取血液及组织标本，检测血清丙氨酸氨基转移酶（ALT）及透明质酸（HA）水平；TUNEL法检测SEC凋亡，透射电镜观察细胞凋亡的形态学改变。结果UW12h组168h存活率为50％，显著低于UW1h组（F=6．39，P〈0．05）。UW12h组肝移植后血清ALT、HA水平明显高于UW1h组（F=3．99，P〈0．05；F=12．43，P〈0．05），两组大鼠ALT水平均于术后6h达高峰。UW12h组SEC凋亡指数（AI）明显高于UW1h组和假手术组（F值分别为63．58和86．58，P值均〈0．01），两组大鼠SEC的AI也于术后6h达高峰，与血中丙氨酸氨基转移酶（ALT）的高峰时相点一致。且两组大鼠SEC的AI均与ALT水平呈显著正相关（，值分别为1．0和0．962，P〈0．05）。结论SEC凋亡程度与移植肝肝细胞损害呈显著正相关，SEC凋亡是冷保存再灌注损伤的关锋环节。     

肝窦内皮细胞在肝细胞再生中的作用

肝窦内皮细胞（LSEC）是最先接触肝脏血流的细胞群,在肝细胞和血液间形成一个通透性屏障。肝窦缺乏基底膜,内皮细胞间缺乏紧密连接,内皮细胞上富有开放的窗孔。由于LSEC特殊的解剖结构和生理功能,决定了其在肝细胞再生中发挥重要作用。     

胆酸对大鼠肝部分切除术后肝细胞脂质代谢及法尼醇X受体表达的影响

目的探讨胆酸对肝细胞脂质代谢、法尼醇X受体(FXR)及肝再生的影响。方法建立部分肝切除大鼠模型,随机分成3组:G1组(正常喂养),G2组(给予0.2%胆酸喂养),G3组(正常饮食中加入50%葡萄糖),每组10只,喂养后7 d切除大鼠70%肝组织,于术后72 h取出肝组织及血液标本,检测相关指标。RT-PCR和Western印迹检测SHP、CYP7A1、BSEP的表达;试剂盒检测肝细胞中甘油三酯、胆固醇的水平。结果与G1相比,G2组小异二聚体伴侣(SHP)、胆盐输出泵(BSEP)表达显著升高(P0.05),胆固醇7α-羟化醇(CYP7A1)表达显著降低(P0.05);G3组SHP、BSEP表达略增高(P0.05),CYP7A1显著升高(P0.05)。G2组甘油三酯(TG)水平显著降低,胆固醇(TC)含量显著升高,而G3组TG略升高,TC含量降低(均P0.05)。结论胆酸可促进肝细胞再生,FXR在调控肝细胞代谢中发挥重要作用。     

Vascular endothelial growth factor secreted by replicating hepatocytes induces sinusoidal endothelial cell proliferation during regeneration after partial hepatectomy in rats.

BACKGROUND: The aim of this study was to investigate regulatory mechanisms of sinusoidal endothelial cell (SEC) proliferation after hepatectomy in rats. METHODS: We investigated expressions of vascular endothelial cell growth factor (VEGF) and its receptors, flt-1 and KDR/flk-1, in regenerating liver after 70% hepatectomy. Proliferation of both hepatocytes and SECs was also monitored by evaluating the proliferating cell nuclear antigen (PCNA) labeling index. Furthermore, VEGF production by cultured hepatocytes isolated at different times after hepatectomy was measured in vitro. RESULTS: The expression of VEGF mRNA was increased markedly between 48 and 72 h after hepatectomy, and thereafter decreasing gradually. The immunohistochemical staining revealed that expression of VEGF started to increase 24 h after hepatectomy, with a peak at 72 h, and the majority of the VEGF-positive cells were hepatocytes located in periportal areas. Meanwhile, expression of flt-1 and KDR/flk-1 was observed along the sinusoids even before hepatectomy, but was increased between 72 and 120 h. Furthermore, VEGF production by cultured hepatocytes isolated 72 h after hepatectomy was significantly increased. The PCNA labeling index of the SECs exhibited a delayed and slower regenerative response in comparison to the hepatocytes, reaching a peak at 72 h. CONCLUSIONS: These data strongly suggest that VEGF secreted by proliferating hepatocytes may represent an important stimulator of SEC proliferation.     

Functional regeneration in liver of old rats after partial hepatectomy

This study suggests that changes in liver protein metabolism occurring with age are not due to changes in the genome. Regenerating rat liver in old animals has regained functional properties of young rat liver.Specifically albumin synthesis, which is elevated in old animals, returns to young rat levels in old rats for several weeks after partial hepatectomy. Both in vivo and in vitro studies support this evidence. Old rat liver ferritin also undergoes changes in regenerating liver. The amount of ferritin iron/g liver falls to one half, the amount of iron/mg ferritin protein drops, but the amount of ferritin protein/g liver remains constant in regenerated old rat liver. The half-life of ferritin in regenerated old rat liver (2·3 days) is much shorter than in old rat liver controls (3·9 days) and approaches that of young rat liver ferritin (2·1 days).Determinations were done at a time when liver weight had been fully restored following removal of 67 per cent of the liver. Functional properties of old rat liver are restored by 12 weeks after partial hepatectomy.     

Stimulation of DNA synthesis in hepatocytes by Kupffer cells after partial hepatectomy

The role of Kupffer cells during reparative regeneration of rat liver was investigated with an in vitro experimental model. Conditioned media from primary cultures of Kupffer cells isolated from intact and regenerating liver were added to primary cultures of hepatocytes, and [3H]thymidine incorporation into DNA was studied. Kupffer cell-conditioned media from intact liver and regenerating remnant liver significantly stimulated DNA synthesis in hepatocytes as compared with control media (p less than 0.05). Moreover, the stimulating activity of Kupffer cells prepared from regenerating liver at 6 and 12 hr after partial hepatectomy was significantly higher than that of Kupffer cells from untreated rats (p less than 0.05). The activity was found in serum-free conditioned media. This stimulating activity exponentially increased as the increase of the number of the cultured cells, indicating that the stimulating activity was released directly by cultured Kupffer cells. These results suggest that Kupffer cells stimulate DNA synthesis in hepatocytes by producing and releasing certain factor(s) at an early stage of liver regeneration after partial hepatectomy.     

Kinetic changes of liver regeneration and hepatocellular carcinoma cells after partial hepatectomy in rats

We investigated, using rats, the effect of partial hepatectomy (PH) on hepatocellular carcinoma (HCC, KDH-8 and AH-66) cells, and the effect of HCC cells on the regeneration of remaining hepatocytes after PH. Our results showed that PH significantly enhanced the growth of HCC cells in rats. Tumor volume increased more significantly in the partially hepatectomized group (H-group) than in the control group, and the tumor wet weights on the 14th postoperative day were significantly higher in the H-group than in the control group. Such an enhanced growth effect of PH on the injected (s.c) HCC cells was related to an abrupt increase of tumor volume within 24 hours after operation, which was supported by the mitotic indices (MI) of the KDH-8 cells. These phenomena of the enhanced growth of the HCC cells following PH were not observed at all in rats injected with estrogen receptor (ER)-negative mammary carcinoma (SST-2) or nonepithelial fibrosarcoma (KMT-75) cells. The MIs of the remaining hepatocytes after PH increased abruptly at the 30th postoperative hour and reached a maximum at the 36th postoperative hour, and the MIs were significantly higher in the H-group with the KDH-8 cells than in the H-group without them from the 42th to the 60th postoperative hour. In the control group, the MIs of hepatocytes were not regardless of the presence of KDH-8 cells. From these results, we speculate that some growth factor(s) induced by PH may act on injected (s.c.) HCC cells, and that the other growth factor(s) secreted by HCC cells may act on the regenerating hepatocytes after PH. This work was supported in part by a grant from the Japanese Ministry of Education. Science and Culture.     

Role of neutrophils in sinusoidal endothelial cell injury after extensive hepatectomy in cholestatic rats

BACKGROUND AND AIMS: The authors have shown previously that sinusoidal endothelial cell injury developed concomitantly with the accumulation of neutrophils in the hepatic sinusoidal space in cholestatic rats after extensive hepatectomy. The aim of the present study was to investigate the role of neutrophils in the development of this kind of endothelial cell injury. METHODS: Rats underwent 78% partial hepatectomy after 2 weeks of cholestasis, and subsequent external biliary drainage for 5 days. To decrease the number of neutrophils, antirat neutrophil serum was administered intraperitoneally. Some serum parameters and histological specimens were examined 48 h after partial hepatectomy. RESULTS: Anti-neutrophil serum significantly reduced the number of accumulated neutrophils in the hepatic sinusoids. Although the purine nucleoside phosphorylase: alanine aminotransferase ratio, a marker of non-parenchymal cell injury, was increased in cholestatic-hepatectomized rats, this abnormality was significantly attenuated by the treatment with antineutrophil serum. Electron microscopically, focal detachment of cytoplasms of sinusoidal endothelial cells was observed occasionally in cholestatic-hepatectomized rats, but was not found in the antirat neutrophil serum-treated rats. CONCLUSION: These results indicate that accumulated neutrophils might be important effector cells in the pathogenesis of sinusoidal endothelial cell injury after extensive hepatectomy in cholestatic rats, even after appropriate external biliary drainage.