乙型肝炎肝组织血管内皮细胞生长因子的表达

目的　研究血管内皮细胞生长因子（ ＶＥＧＦ） 与乙型肝炎（ 乙肝）分级（ Ｇ） 和分期（Ｓ） 的关系．方法　乙肝活检肝标本１５０ 例,用ＶＥＧＦ 单克隆抗体进行免疫组化（ＳＰ 法） 染色．结果　ＶＥＧＦ 在肝组织表达有胞浆型、膜窦型及窦内皮细胞型;ＶＥＧＦ 主要由肝细胞分泌,其次在肝窦内皮细胞、贮脂细胞、成肌纤维细胞,单形核细胞也示阳性． 无明显病变的血管内皮细胞及肝细胞ＶＥＧＦ 染色阴性． 提示随分级增高ＶＥＧＦ表达增强,其间有极显著性差异（ Ｐ＜ ０－０１） ;而Ｓ 低分值者ＶＥＧＦ 多示阳性表达,Ｓ 较高分值者其多为强阳性表达,两者有明显不同（ Ｐ＜ ０－０１） ．结论　ＶＥＧＦ 表达与乙肝Ｇ 和Ｓ 呈相关．     

氯化钴诱导人肝窦内皮细胞缺氧模型特点

目的观察氯化钴(CoCl_2)诱导人肝窦内皮细胞(HHSEC)缺氧模型特点。方法不同浓度CoCl2(0~800μmol/L)与HHSEC细胞孵育24 h,CCK8法检测细胞活力;50~200μmol/L CoCl2与HHSEC细胞孵育,Transwell实验检测细胞迁移;Matrigel管腔生成实验检测细胞管腔形成情况;蛋白质免疫检测细胞HIF-1α、vWF、VEGF蛋白表达;免疫荧光染色观察HIF-1α核转位。结果与对照组比较,50~200μmol/L CoCl2组HHSEC细胞活力明显增加,细胞迁移到膜下的数量显著增多,并且形成丰富而密闭的管状结构。50μmol/L、200μmol/L CoCl2促进HHSEC中缺氧诱导因子1α(HIF-1α)、第八因子相关抗原(vWF)、血管内皮生长因子(VEGF)表达,其中200μmol/L CoCl2组HIF-1α、vWF表达较50μmol/L CoCl2组高。结论 50μmol/L、200μmol/L低浓度CoCl2可诱导人肝窦内皮细胞缺氧、血管新生,其作用机制与促进HIF-1α表达及核转位相关。     

依泽替米贝抑制大鼠血管平滑肌细胞荷脂

背景和目的治疗性血管新生在缺血性疾病包括对动脉粥样硬化的干预中具有实际意义,我们近年研究发现,生理性微电场可介导血管内皮细胞血管新生样反应,但其机制尚待深入研究。本研究拟探讨微电场影响内皮细胞血管新生相关基因的表达及其机制。方法应用微电场对血管内皮细胞进行刺激;利用显微成像系统及共聚焦显微镜研究内皮细胞的形态与结构;用ELISA法和/或RT-PCR测定内皮细胞血管新生相关基因的表达;用特异抑制剂研究血管内皮生长因子/血管内皮生长因子受体(VEGF/VEGFR)介导的细胞信号通路在内皮细胞血管新生及其基因表达中的作用。结果生理性微电场可刺激血管内皮细胞变长和定向排列,以及细胞定向移动。这些细胞行为在微血管内皮细胞(HMEC-1)和大血管内皮细胞(HUVEC)的反应存在明显差异。微电场刺激血管内皮细胞使VEGF165、VEGF121和白细胞介素8(IL-8)表达上调,而对其他血管新生相关分子如碱性成纤维细胞生长因子(bFGF)、转化生长因子β(TGF-β)以及内皮型一氧化氮合酶(eNOS)等mRNA表达影响不明显。VEGFR抑制剂作用于血管内皮细胞后,抑制微电场对内皮细胞VEGF和IL-8的表达及内皮细胞定向排列...     

慢性乙型肝炎肝组织中碱性成纤维细胞生长因子及其mRNA的表达

目的研究肝组织中碱性成纤维细胞生长因子(bFGF)及bFGFmRNA的表达与慢性乙型肝炎(CHB)肝血管增生、改建及肝血管纤维化的关系。方法对120例CHB肝标本进行bFGF免疫组织化学(免疫组化)染色及bFGFmRNA原位杂交。结果随着CHB肝细胞变性坏死及肝血管病变的加重,bFGF在肝血管及肝窦壁表达强阳性逐渐上升(P<0.01),部分固缩性肝细胞也示强阳性显色。原位杂交显示,bFGFmRNA主要分布于血管纤维化区域肝窦壁及部分肝细胞。结论bFGF通过激活血管及肝窦内皮细胞,引发其增生和凋亡,最终导致肝血管纤维化、肝窦毛细血管化及假小叶纤维间隔形成。     

慢性乙型肝炎患者肝组织低氧诱导因子1α的表达变化

目的研究肝组织中低氧诱导因子（HIF）-1α的表达与慢性乙型肝炎（CHB）患者肝脏微循环障碍的关系。方法对81例CHB患者和5例正常人的肝标本进行免疫组织化学染色,并用透射电镜观察肝组织超微结构的变化。结果 HIF-1α在肝组织中的表达强度和范围与CHB患者肝脏微循环障碍程度密切相关,电镜示肝窦腔内红细胞聚集、狄氏腔中胶原纤维沉积及肝窦内皮细胞表面有基底膜形成。结论 HIF-1α通过激活血管增生,最终导致血管纤维化和肝窦毛细血管化,加重肝脏微循环障碍。     

血管内皮细胞生长因子在唇癌中的表达

目的 探讨血管内皮细胞生长因子(VEGF)在唇癌表达的临床意义.方法 采用免疫组织化学SP法检测32例唇癌组织、15例正常唇黏膜组织中血管内皮细胞生长因子(VEGF)表达水平的变化.〖HT6H〗结果 在正常唇黏膜组织中VEGF表达阳性率为4/15;而在唇癌细胞中VEGF表达阳性率为26/32,二者比较具有统计学意义(P<0.01).随着病理分级的升高,VEGF阳性表达强度增高,与病理分级呈正相关(rs=0.672,P<0.001);TNM分期与VEGF表达无关.结论 VEGF在唇癌发生、发展、浸润及转移中具有重要的作用,可作为一种有价值的标志物,在判断肿瘤的恶性程度和预后及治疗方面有重要的临床应用价值.     

内皮型一氧化氮合酶在慢性乙型肝炎肝组织中的表达

目的研究内皮型一氧化氮合酶(endothelium-type nitric oxide synthase,eNOS)在慢性乙型肝炎肝组织中的表达及其与病理改变的关系。方法应用免疫组化法观察了41例慢性乙型肝炎患者肝组织中eNOS的变化。结果 eNOS见于肝细胞,窦内皮细胞,枯否细胞,血管内皮细胞,单个核细胞,及增生的卵圆细胞,呈胞浆型,细颗粒型,粗颗粒型及胞膜型分布,以肝细胞为主,在炎症病变活动区相对集中。并发现其表达随肝组织病变活动程度增加而增强,与炎症程度的相关系数为0.5327(P<0.05),与纤维化程度无明显相关性。结论 eNOS与慢性乙肝肝组织病理改变密切相关。     

含溶栓颗粒血清对TNF-α损伤人脐静脉内皮细胞VEGF的影响

目的探讨溶栓颗粒对受损血管内皮细胞保护的可能机制。方法用肿瘤坏死因子-α（TNF-α）损伤人脐静脉内皮细胞（HUVEC）造模,用含大、申、小剂量溶栓颗粒的大鼠血清干预受损HUVEC,应用HE染色,观察细胞形态变化,免疫组化法观察血管内皮生长因子（VEGF）的表达。结果应用TNF-α 40ng／mL可以造成HUVEC损伤,表现细胞数量下降,皱缩、变形,分裂相细胞明显增加,VEGF表达明显增多。含大、中剂量溶栓颗粒的大鼠血清能减少VEGF表达,减少细胞有丝分裂。结论溶栓颗粒可以保护因炎性介质增加而受损的血管内皮细胞,这种保护作用可能与减少VEGF表达有关。     

转染VEGF165的大鼠血管内皮细胞与胰岛共移植对糖尿病大鼠的治疗作用

目的:探讨VEGF165转染大鼠血管内皮细胞诱导移植胰岛再血管化及对功能的影响.方法:受体糖尿病大鼠随机分为3组,对照组于肾被膜下移植300当量(1当量相当于1个直径为150μm的胰岛)胰岛,转染组和内皮细胞组分别加入1×106转染质粒pIRES2-EGFP/VEGF165的血管内皮细胞和正常血管内皮细胞.移植后监测血糖及血清胰岛素水平.术后10d行静脉糖耐量实验(IVGTT).术后14d,取受者肾脏HE染色及Insulin-6,VEGF和CD34免疫组化染色,计算微血管密度.结果:实验组大鼠于移植术后3d血糖及胰岛素水平恢复正常.对照组和内皮细胞组虽有所改善,但未恢复到正常水平.IVGTT显示实验组K值(K=2.69)与正常大鼠相似,对照组和内皮细胞组K值分别为1.9和1.87,两组间无明显差异,而与实验组有明显差异(P<0.05).实验组大鼠肾被膜下可见成团胰岛,Insulin-6免疫组化呈阳性,周围及内部有大量内皮细胞.VEGF165免疫组化及CD34免疫组化染色呈阳性.对照组和内皮细胞组肾被膜下的细胞团中心细胞较少,部分被纤维组织代替,内部仅有少量CD34染色阳性的内皮细胞.Insulin-6免疫组化仅有少量细胞染成棕黄色.VEGF165免疫组化呈阴性.对照组(11.43±2.22)和内皮细胞组MVD(10.9±2.45)无显著差异,而与实验组间(74.3±6.74)有明显差别(P<0.05).结论:VEGF165转染大鼠血管内皮细胞可以诱导移植胰岛新生血管生成,促进再血管化,降低移植胰岛早期死亡率,减少供胰用量.     

基质金属蛋白酶-2、-9与肝纤维化

研究基质金属蛋白酶－2（MMP－2）、基质金属蛋白酶－9（MMP－9）在实验性肝纤维化发生发展过程中的表达及动态变化。用皮下注射CCL4的方法复制大鼠化学性肝纤维化模型。用免疫组织化学方法在4周、8周、12周分别检测肝组织中MMP－2、MMP－9的表达。MMP－2主要位于血管内皮细胞、窦内皮细胞及肝窦细胞的胞浆；MMP－9主要位于静 肝细胞及肝窦细胞的胞浆。MMP－2、MMP－9免疫组化阳性表达面积，肝纤维化明显高于对照组（P＜0．05），并随造模时间延长而进行性增加。MMP－2、MMP－9参与了肝纤维化的进展，可能促进作用。     

The mechanisms of hepatic sinusoidal endothelial cell regeneration: A possible communication system associated with vascular endothelial growth factor in liver cells

Vascular endothelial growth factor (VEGF) has been shown to induce proliferation of sinusoidal endothelial cells in primary culture. To elucidate the mechanisms of sinusoidal endothelial cell regeneration in vivo, mRNA expression of VEGF and its receptors, flt-1 and KDR/flk-1, were studied in rat livers. Northern blot analysis revealed that VEGF-mRNA was expressed in hepatocytes immediately after isolation from normal rats. In contrast, non-parenchymal cells, including sinusoidal endothelial cells, expressed VEGF receptor-mRNA. Vascular endothelial growth factor-mRNA expression in hepatocytes was decreased during primary culture, but increased following a peak of DNA synthesis, induced by addition of epidermal growth factor or hepatocyte growth factor to the culture medium at 24 h of plating. In a 70% resected rat liver, VEGF-mRNA expression increased with a peak at 72 h after the operation, and mRNA expression of VEGF receptors between 72 and 168 h. In such a liver, mitosis was maximal in hepatocytes at 36 h and in sinusoidal endothelial cells at 96 h. Also, mRNA expression of both VEGF and its receptors was significantly increased in carbon tetrachloride-intoxicated rat liver compared with normal rat liver. Vascular endothelial growth factor expression was minimal in Kupffer cells isolated from normal rats, but marked in activated Kupffer cells and hepatic macrophages from the intoxicated rats. Vascular endothelial growth factor-mRNA expression was also increased in activated stellate cells from these rats and in the cells activated during primary culture compared with quiescent cells. We conclude that increased levels of VEGF expression in regenerating hepatocytes may contribute to the proliferation of sinusoidal endothelial cells in partially resected rat liver, probably through VEGF receptors up-regulated on the cells. Also, VEGF derived from activated Kupffer cells, hepatic macrophages and stellate cells may be involved in this proliferation in injured rat liver.     

Spatiotemporal expression of angiogenesis growth factor receptors during the revascularization of regenerating rat liver.

Regenerating liver was evaluated for the spatiotemporal expression of angiogenic growth factor receptors on endothelial cell (EC) membranes during revascularization resulting from 70% partial hepatectomy (PHx). Fractions enriched in EC membranes were examined by Western blot for angiogenic growth factor receptor expression from 1 to 14 days after PHx. Increases in vascular endothelial growth factor (VEGF) receptors Flt-1 and Flk-1/KDR, angiopoietin receptors Tie-1, Tie-2, and platelet-derived growth factor receptor beta (PDGF-Rbeta), modest increases in epidermal growth factor receptor (EGF-R), and no increase in hepatocyte growth factor receptor (c-Met) or fibroblast growth factor receptors (FGF-R) were observed in isolated membranes during EC proliferation. All receptors were tyrosine phosphorylated, and therefore activated, during peak expression. Immunofluorescence staining of regenerating liver identified populations with increased receptor expression, indicating cells receptive to ligand signaling. EGF-R was upregulated evenly throughout the sinusoidal membrane, whereas c-Met was observed on hepatocyte canaliculae, bile duct epithelium, and large vessel EC. Tie-2 and PDGF-Rbeta were increased on sinusoidal and large vessel EC, whereas Tie-1 was expressed in EC surrounding avascular hepatic islands. Flk-1/KDR was increased on large vessels with slight increases on sinusoidal EC, whereas Flt-1 was increased in arterioles, sinusoidal EC as well as in hepatocytes. Although Flt-1 was phosphorylated on isolated hepatocytes, vascular endothelial growth factor(165) (VEGF(165)) did not induce a proliferative or motogenic response. Proliferation assays on isolated EC indicated responsiveness to VEGF(165), but synergism among several growth factors including PDGF-BB was also observed. The data identify novel autocrine and paracrine interactions and indicate that each growth factor acts on a specific set of EC at specific times during revascularization of regenerating liver.     

Vascular endothelial growth factor reduces Fas-mediated acute liver injury in mice

Background and Aim:  Fulminant hepatitis is still a fatal liver disease, and no specific treatment for it has been available. Vascular endothelial growth factor (VEGF) is the focus of attention because of its various actions. We investigated the effect of vascular endothelial growth factor (VEGF) on Fas-induced fulminant hepatic failure (FHF).
Method:  Male Balb/c mice were treated with an intraperitoneal injection of an anti-Fas antibody (Jo-2 Ab) with or without premedication with intraperitoneally administered human recombinant VEGF.
Results:  The serum level of alanine aminotransferase (ALT) was up to 300 times higher that of normal mice following the Jo-2 Ab injection, and histological analysis revealed hepatic injury and massive hepatocyte apoptosis. The VEGF significantly suppressed an elevation in serum ALT levels and hepatocyte apoptosis. Immunohistochemically, VEGF-treated mice showed that Bcl-xL in hepatocytes was strongly expressed.
Conclusions:  Since hepatocytes do not express VEGF receptors, we speculated that VEGF acts on sinusoidal endothelial cells (SECs) and promotes production of cytokines such as hepatocyte growth factor in SECs, resulting in reducing apoptosis through an increase expression of Bcl-xL in hepatocytes. We suggest that VEGF has a potent antiapoptotic effect on hepatocytes through cell–cell interaction between SECs and hepatocytes.     

Simultaneous transfer of vascular endothelial growth factor and hepatocyte growth factor genes effectively promotes liver regeneration after hepatectomy in cirrhotic rats

BACKGROUND/AIMS: Liver regeneration in a cirrhotic liver is unsatisfactory. In the course of liver regeneration, non-parenchymal cells such as sinusoidal endothelial cells as well as hepatocytes increase in number while the liver structure and physiological functions are maintained. The aim of this study was to examine whether sufficient liver regeneration could be obtained by the simultaneous, preoperative injection of recombinant adenoviral vectors encoding human vascular endothelial growth factor (VEGF), a potent mitogen for sinusoidal endothelial cells, (pAxCAVEGF) and rat hepatocyte growth factor (HGF), a potent mitogen for hepatocytes, (pAxCAHGF) in 70% hepatectomized cirrhotic rats. METHODOLOGY: Forty-eight hours before 70% hepatectomy, dimethylnitrosamine-induced cirrhotic rats were infused intravenously with pAxCAVEGF or with pAxCAVEGF and pAxCAHGF, or with a control virus encoding Escherichia coli beta-galactosidase (pAxCALacZ). RESULTS: Strong VEGF mRNA expressions were shown in the livers of VEGF and VEGF/HGF-treated animals. The plasma HGF concentrations in the VEGF/HGF-treated rats were elevated compared with the other groups. Proliferating cell nuclear antigen immunostaining showed increased labeling indices of hepatocytes in the VEGF/HGF-treated rats at 24 and 48 h after hepatectomy. PCNA labeling indices of SECs were increased in the VEGF and VEGF/HGF-treated rats compared with the control animals at 24 and 48 h after hepatectomy. Moreover, the hepatic regeneration rate after hepatectomy was significantly augmented by the VEGF and VEGF/HGF treatment. CONCLUSIONS: Simultaneous preoperative injection of recombinant adenoviral vectors encoding VEGF and HGF effectively stimulates liver regeneration in cirrhotic rats.     

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.     

Vascular adhesion molecules in acute and chronic liver inflammation.

Adhesion to and penetration through the sinusoidal vascular endothelium is a mandatory step for leukocyte migration and accumulation at sites of liver inflammation. This leukocyte trafficking is controlled by interactions between adhesion molecules on leukocytes and corresponding ligands on endothelial cells. We have analyzed the in situ distribution of two recently described vascular adhesion molecules (i.e., endothelial leukocyte adhesion molecule-1 and vascular cell adhesion molecule-1) and of the lymphocyte "homing" receptor cluster of differentiation antigen-44 in normal and inflamed liver biopsy specimens. Endothelial leukocyte adhesion molecule-1 and vascular cell adhesion molecule-1 were absent from normal liver tissue, but they were strongly expressed on sinusoidal lining cells in inflammatory liver disease. Endothelial leukocyte adhesion molecule-1 expression predominated diffusely throughout the liver parenchyma in acute hepatitis; in contrast, vascular cell adhesion molecule-1 was mainly expressed in areas of periportal and intralobular inflammation in chronic active and persistent hepatitis. The "homing" receptor cluster of differentiation antigen-44 was weakly expressed on scattered mononuclear cells and on sinusoidal lining cells in normal liver tissue, but it was strongly up-regulated on mononuclear inflammatory cells and sinusoidal lining cells in acute and chronic hepatitis. In addition, reactivity for the cluster of differentiation antigen-44 was found on the membranes of variously sized clusters of hepatocytes in biopsy specimens with acute hepatitis. De novo or up-regulated expression of these adhesion molecules on sinusoidal lining cells in inflamed liver biopsy specimens indicates that these cells actively modulate their phenotype in response to environmental factors, thus playing a key role in the recruitment of leukocytes in acute and chronic liver inflammation.     

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.