肝窦内皮细胞研究进展

肝窦内皮细胞（sinusoidal endothelical cell,SEC)是数量最多的肝脏非实质细胞,占非实质细胞总数的44％－60％,其形态结构和功能具有异质性。SEC与肝微循环、血脂代谢、内分泌代谢、内环境稳定、肝再生、肝细胞移植和肝癌发生等密切相关。     

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。     

肝窦内皮细胞研究进展

肝窦内皮细胞(sinusoidal endothelial cell,SEC)是数量最多的肝脏非实质细胞,占非实质细胞总数的44％～60％,其形态结构和功能具有异质性。SEC与肝微循环、血脂代谢、内分泌代谢、内环境稳定、肝再生、肝细胞移植和肝癌发生等密切相关。     

肝窦内皮细胞与肝再生

肝窦内皮细胞(liver sinusoidal endothelial cells,LSECs)是肝脏非实质细胞中数目最多的细胞,约占肝非实质细胞总数的70％,在表型、功能上与普通毛细血管内皮细胞有较大差异.有关LSECs在肝再生过程中作用的研究相对较少.近年来,关于LSECs再生行为及其与肝内其他细胞成分相互作用的研究结果提示其在肝再生和肝衰竭中具有重要作用,但具体机制尚未完全明确.现就LSECs的再生行为及其在肝再生中的作用,以及以LSECs为靶点干预肝再生等进行综述.     

肝血窦内皮细胞在肝再生和肝纤维化发生中的作用

肝血窦内皮细胞是肝脏非实质细胞的主要组成细胞,是覆盖于肝窦的薄层扁平状细胞,表面富含窗孔,是肝窦和窦状间隙之间溶质交换的开放通道。肝血窦内皮细胞的分泌功能尤其是Wnt信号通路在维持Axin2+源性肝细胞的自我更新、促进肝部分切除或肝损伤时肝再生中均发挥重要的保护作用。肝损伤时,肝血窦内皮细胞结构发生改变,表现为窗孔消失和内皮下基底膜的形成,即肝窦毛细血管化。肝窦毛细血管化既是肝纤维化发生的前奏,也会促进肝纤维化的进展。肝窦内皮细胞在不同生理或病理状态下可通过信号通路的转换实现肝再生和肝纤维化调控作用的转换。肝血窦内皮细胞参与肝再生和肝纤维化机制的深入认识有望为慢性肝病的防治提供新的治疗靶点。     

肝窦内皮细胞在肝损伤中的功能研究进展

肝窦内皮细胞（liver sinusoidal endothelial cells, LSECs）位于肝血窦表面,是肝脏与血液接触的第一道防线,也是肝脏中含量最多的非实质细胞。在生理情况下,LSECs通过参与物质运输、代谢废物清除而诱导肝脏免疫耐受,从而维持肝脏稳态;在病理情况下,LSECs通过抗原递呈促进肝脏炎症反应。LSECs在维持肝再生和肝纤维化平衡中发挥了重要的调节作用。本文对LSECs功能、LSECs在肝损伤中的变化、调节LSECs功能相关的信号通路以及LSECs与肝内其他细胞的相互作用等四方面研究进展进行综述,从而进一步明确LSECs的功能及在肝损伤中的作用。     

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。     

肝窦内皮细胞损伤在大鼠肝纤维化形成中的作用

目的 研究肝窦内皮细胞损伤在二甲基亚硝胺大鼠肝纤维化形成中的作用。方法 采用二甲基亚硝胺(dimethylnitrosamine,DMN)4周12次腹腔注射制备大鼠肝纤维化模型,应用电镜技术、免疫组织化学及图像分析方法结合血清生化测定,24周动态观察肝纤维化形成过程中肝窦内皮细胞损伤及其表型的改变。结果 造模2d后肝结构未见明显改变,肝窦内皮细胞(sinusoidal endothelial cell,SEC)远侧胞浆窗孔数减少、造模1周SEC失窗孔更明显,肝组织内未见明显变性坏死及纤维间隔形成,造模4周时见肝组织内大片出血坏死,有大量假小叶形成,内皮下出现SEC窗孔减少。SEC失窗孔早于肝细胞发生较为严重的坏死、肝纤维化的形成以及肝窦内皮下基底膜的形成。造模4周HA(ng/ml)和肝羟脯氨酸(ug/g)平均含量分别为231.30±143.80和223.04±37.09,对照组分别为56.50±18.10和61.55±20.85,t值在3.14～8.28,P<0.05。结论 DMN引起大鼠肝窦内皮细胞损伤及其表型改变可能是其诱导肝纤维化重要的始动机制之一。     

The role of liver sinusoidal endothelial cells in liver remodeling after injury

Liver transplantation is the optimal treatment for patients with end-stage liver disease, metabolic liver diseases, and hepatic malignancies that are not amenable to resection. Hepatic ischemia-reperfusion injury (IRI) is the main problem in liver transplantation and liver resection, leading to parenchymal cell injury and organ dysfunction. The damage of liver sinusoidal endothelial cells (LSECs) is a critical event in IRI. LSECs work as an important regulating factor of liver regeneration after partial hepatectomy. This review primarily describes the mechanisms of LSECs injury in IRI and explores the roles of LSECs in liver regeneration, and briefly introduces the protective strategies targeting LSECs damaged in IRI.     

肝血窦内皮细胞在非酒精性脂肪性肝病发展中的作用

非酒精性脂肪性肝病(NAFLD)是以肝脏脂肪变、炎症和纤维化为主要表现的临床代谢综合征,日渐成为严重影响公众健康的常见慢性肝病。肝血窦内皮细胞(LSEC)是肝脏组织特化的血管内皮细胞,作为一道重要的血管屏障,其对肝脏细胞吸收和代谢源自肠道血液中的营养与物质成分发挥重要调节作用。介绍了NAFLD发生发展进程中LSEC毛细血管化、血管功能障碍及其参与调控肝脏炎症、血管生成、肝纤维化的研究进展。     

T lymphocytes interact with hepatocytes through fenestrations in murine liver sinusoidal endothelial cells

The liver has an established ability to induce tolerance. Recent evidence indicates that this unique property might be related to its distinctive architecture allowing T cells to be activated in situ independently of lymphoid tissues. Unlike lymph node-activated T cells, liver-activated T cells are short-lived, a mechanism that might contribute to the "liver tolerance effect." Although the potential role of hepatocytes as tolerogenic antigen-presenting cells has been demonstrated, the question as to whether these cells are able to interact with CD8(+) T cells in physiological settings remains controversial. Contradicting the immunological dogma stating that na?ve T lymphocytes are prevented from interacting with parenchymal cells within non-lymphoid organs by an impenetrable endothelial barrier, we show here that the unique morphology of the liver sinusoidal endothelial cell (LSEC) permits interactions between lymphocytes and hepatocytes. Using electron microscopy, we demonstrate that liver resident lymphocytes as well as circulating na?ve CD8(+) T cells make direct contact with hepatocytes through cytoplasmic extensions penetrating the endothelial fenestrations that perforate the LSECs. Furthermore, the expression of molecules required for primary T cell activation, MHC class I and ICAM-1, is polarized on hepatocytes to the perisinusoidal cell membrane, thus maximizing the opportunity for interactions with circulating lymphocytes. In conclusion, this study has identified, at the ultrastructural level, a unique type of interaction between na?ve T lymphocytes and liver parenchymal cells in vivo. These results hold implications for the pathogenesis of viral hepatitis in which hepatocytes may represent the main antigen-presenting cell, and for the development of immune tolerance as lymphocytes pass through the liver.     

N-acetylglucosamine-6-phosphate deacetylase in hepatocytes, Kupffer cells and sinusoidal endothelial cells from rat liver

The activity of N-acetylglucosamine-6-phosphate deacetylase, a key enzyme in the pathway of N-acetylglucosamine catabolism, was measured in hepatocytes, Kupffer cells and sinusoidal endothelial cells from rat liver and cultured human skin fibroblasts. Kupffer cells and endothelial cells had similar high levels of deacetylase activity that were more than twice the level observed in fibroblasts. In contrast, hepatocytes had extremely low activity (several hundredfold less than Kupffer cells and endothelial cells). A major implication of deacetylase deficiency in hepatocytes is that N-acetylglucosamine generated as a result of the catabolism of complex carbohydrates in these cells cannot enter glycolysis and must be largely reused for the synthesis of plasma glycoproteins and other N-acetylglucosamine-containing macromolecules.     

Lymphocyte traffic through sinusoidal endothelial cells is regulated by hepatocytes

Crosstalk between hepatic sinusoidal ECs and closely juxtaposed hepatocytes via vascular endothelial growth factor is essential for the maintenance of sinusoidal endothelial growth and differentiation. We propose that paracrine interactions between endothelial cells and hepatocytes also may be responsible for the unique complement of adhesion receptors expressed on sinusoidal endothelium that regulate the recruitment of lymphocytes into the liver. To address this hypothesis, we developed an in vitro model of the hepatic sinusoid in which flowing lymphocytes could interact with hepatic endothelium conditioned by the presence of hepatocytes. Human hepatic sinusoidal endothelial cells cocultured with hepatocytes were activated so that they supported the adhesion of lymphocytes at levels equivalent to those seen on endothelium stimulated with the inflammatory cytokine tumour necrosis factor-beta. Lymphocyte adhesion was supported by intracellular adhesion molecule 1, vascular cell adhesion molecule 1, and E-selectin, with an additional contribution from the novel adhesion receptor VAP-1. In conclusion, we show that interactions between hepatocytes and endothelial cells amplify leukocyte recruitment through the sinusoids by regulating the expression and function of endothelial adhesion molecules. These paracrine interactions may be responsible for the induction of the adhesion molecules that support constitutive lymphocyte recruitment to the liver as well as contributing significantly to the patterns of leukocyte adhesion seen during episodes of hepatic inflammation.