组织工程血管种子细胞的研究进展

组织工程血管种子细胞的来源、制取、培养分化、验证及种植已成为组织工程血管研究的关键步骤。目前常用的种子细胞是血管内皮细胞，干细胞如内皮前体细胞、间充质干细胞、脂肪干细胞等，尤其是间充质干细胞及脂肪干细胞具有易于分离培养、增殖能力强和可定向分化为内皮细胞及平滑肌细胞的特点而成为热点研究的种子细胞，干细胞的研究进展将会促进组织工程血管的临床应用。     

体外构建组织工程化小口径血管模型

目的体外构建组织工程化人工血管模型。方法将诱导细胞制成细胞ECMgel悬液培养,镜下观察细胞形态;将诱导的平滑肌细胞和内皮细胞悬液分层种植于支架内表面,以荧光显微镜、扫描电镜和HE染色光镜观察。结果在ECMgel凝胶中细胞生长良好;旋转培养的血管模型,质地均匀,内腔面光滑;HE染色可见血管壁三层结构:内皮细胞层、平滑肌细胞层、PGA 交联胶原层;扫描电镜可见内皮细胞融合成片;荧光显微镜观察可见均匀分布的内皮细胞。结论①ECMgel是携带细胞良好的基质;②旋转培养条件可以促进细胞的贴附和分化;③利用体外诱导的种子细胞分层种植可以构建成与天然血管结构相似的血管模型。     

内皮祖细胞在血管新生及血管组织工程化过程中的生物学意义

内皮祖细胞(EPCs)是能分化为成熟血管内皮细胞的祖细胞,参与了出生后的血管再生和受损内皮的修复过程。近年来围绕以EPCs作为种子细胞来促进血管新生、维持内皮功能完整并构建组织工程化血管方面展开了许多研究。本文就这方面的进展作一综述。     

干细胞分化来源血管内皮细胞研究进展

种子细胞是细胞治疗和组织工程化组织构建的基础,在缺血性疾病细胞治疗和组织工程血管构建中,内皮细胞的来源一直是亟待解决的问题之一.自体血管壁分离获得的内皮细胞由于数量少、体外培养困难、增殖能力有限.应用受到限制.随着干细胞研究的兴起,干细胞逐渐成为内皮细胞来源的研究焦点.就具有向成熟血管内皮细胞分化潜能的干细胞(内皮祖细胞,造血干细胞,骨髓基质干细胞,脂肪来源基质干细胞,胚胎干细胞)来源、分布、特点、诱导分化、动物实验或临床应用及近期相关研究予以综述,并比较各自的优缺点.为内皮细胞来源的选择提供参考.     

组织工程化血管构建中有关VEGF和bFGF的研究进展

内皮细胞是血管组织工程的重要种子细胞,小肠粘膜下基质(SIS)的生物活性和力学特性日益引起人们的关注,细胞因子的生物活性成分及其在组织工程化血管构建中的作用可以从不同角度、不同水平进行研究.本文主要从以下两个方面进行综述:SIS中所含生长因子的含量、类型和分布;内皮细胞中碱性成纤维细胞生长因子和血管内皮细胞生长因子的分泌情况,并着重对剪切力作用下内皮细胞分泌活性的变化进行综述,从而为组织工程化血管的基础研究提供参考.     

组织工程化血管种子细胞研究现状

种子细胞制取、培养、种植的研究是组织工程化血管研究的关键性环节。目前常用于作为组织工程化血管种子细胞的是白体血管壁细胞，如内皮细胞。造血系统来源的干细胞及间充质干细胞由于取材方便，可体外大量培养增殖，无免疫原性的优点，有望成为组织工程化血管的种子细胞主要来源，随着对胚胎干细胞的进一步研究，胚胎干细胞也可作为种子细胞。考虑到流体切应力对种子细胞的影响，动态培养种子细胞可促进种植后细胞的粘附性、细胞生长及功能的发挥，使组织工程血管更符合生理需要。     

组织工程骨血管化的研究进展

组织工程骨血管化的问题是制约构建大块组织工程骨的一个重要方面，迫切需要在材料中构建血管网给种子细胞传输营养物质、氧气和调控因子。血管化可明显促进新生骨的形成，材料的性能和三维结构对血管形成有很大的影响，成骨细胞和血管内皮细胞共同培养时可以相互促进生长，多种细胞因子可以刺激血管的生长并且起协同作用。目前对血管化骨的制备进行了细胞混合培养和使用显微制造技术等一些方法的探索。     

组织工程骨血管化的研究进展

组织工程骨血管化的问题是制约构建大块组织工程骨的一个重要方面 ,迫切需要在材料中构建血管网给种子细胞传输营养物质、氧气和调控因子。血管化可明显促进新生骨的形成 ,材料的性能和三维结构对血管形成有很大的影响 ,成骨细胞和血管内皮细胞共同培养时可以相互促进生长 ,多种细胞因子可以刺激血管的生长并且起协同作用。目前对血管化骨的制备进行了细胞混合培养和使用显微制造技术等一些方法的探索     

新的组织工程种子细胞——内皮祖细胞

内皮祖细胞作为一种在血管领域的干细胞在组织工程中有着广阔的应用前景。内皮祖细胞取材方便，参与新生血管的形成，具有成熟内皮细胞相似的特性。因此，内皮祖细胞可能是组织工程血管、血管植入物再内皮化以及构建组织工程器官血管网络的种子细胞的理想来源。简单介绍了内皮祖细胞的来源、特性以及体外扩增技术，并对其在组织工程中应用的研究进展做一回顾。     

新的组织工程种子细胞--内皮祖细胞

内皮祖细胞作为一种在血管领域的干细胞在组织工程中有着广阔的应用前景.内皮祖细胞取材方便,参与新生血管的形成,具有成熟内皮细胞相似的特性.因此,内皮祖细胞可能是组织工程血管、血管植入物再内皮化以及构建组织工程器官血管网络的种子细胞的理想来源.简单介绍了内皮祖细胞的来源、特性以及体外扩增技术,并对其在组织工程中应用的研究进展做一回顾.     

内皮祖细胞生物学特征及其临床应用

背景：内皮祖细胞已经广泛用于研究缺血性疾病,能促进内皮再生、血管修复及组织中新生血管形成。 目的：综述内皮祖细胞生物学特征及其临床应用的研究进展。 方法：应用计算机检索1997-01/2010-12 PubMed数据库相关文章,检索词为“endothelial progenitor cells,ischemic cerebrovascular disease,early endothelial progenitor cells,late endothelial progenitor cells”,共检索到文献219篇,最终纳入符合标准的文献28篇。 结果与结论：内皮祖细胞定居于成体骨髓,现已证实胎肝、人脐血、成人外周血及骨髓中均存在,且人脐血、外周血中的内皮祖细胞均来源于骨髓。此外在心脏、血管、脂肪组织和骨骼肌等外周组织中也发现内皮祖细胞的存在。内皮祖细胞具有促进内皮再生及血管修复的功能,能促进组织中新生血管形成,在防治血管成形术后再狭窄等血管性疾病中发挥重要作用,其中晚期内皮祖细胞比早期内皮祖细胞更易形成毛细血管,在干细胞移植临床应用于缺血性脑卒中具有广泛的前景。     

Macrophage colony-stimulating factor (M-CSF), as well as granulocyte colony-stimulating factor (G-CSF), accelerates neovascularization

It has been reported that bone marrow cells (BMCs) differentiate into endothelial cells of blood vessels, and that granulocyte colony-stimulating factor (G-CSF) mobilizes progenitors in the BMCs to the peripheral blood, while macrophage colony-stimulating factor (M-CSF) augments the production of monocytes. We examined whether M-CSF augments the differentiation of BMCs into endothelial cells of blood vessels using a hindlimb-ischemic model. Either G-CSF or M-CSF, or both, was administered to the hindlimb-ischemic mice for 3 days. Both M-CSF and G-CSF augmented the differentiation of BMCs into endothelial cells of blood vessels through vascular endothelial cell growth factor (VEGF), resulting in early recovery of blood flow in the ischemic limbs.     

Immunocytochemical localization of xanthine oxidase in rat myocardium

Monoclonal antibodies (MAb's) to xanthine oxidase (XO) (from bovine milk) were produced by hybridoma technique. Culture supernatants were initially screened using enzyme-linked immunoabsorbant assay (ELISA). Forty four positive clones were subcloned and further characterized by ELISA and immunoblot analysis. Out of fifteen clones, which were positive in immunoblot analysis, one clone N2-26 was also positive in immunocytochemical studies. Indirect immunoperoxidase and enzyme histochemistry staining showed that XO activity is present in endothelial cells of capillaries, small blood vessels and also in interstitial cells. Electron microscopy revealed that diaminobenzidine reaction product was distributed in the cytoplasm of interstitial cells and endothelial cells of capillaries and small blood vessels. This is the first report of the presence of XO in interstitial cells and endothelial cells of small blood vessels. Allopurinol, which inhibits the xanthine oxidase activity, did not have any effect on the immunocytochemical staining. Our results in normal rat heart suggest that XO activity is confined to interstitial cells, endothelial cells of capillaries and small blood vessels.     

Postnatal development of blood vessels (capillaries) in the rat olfactory bulb: A light and ultrastructural study

The increase in density and development of blood vessels (capillaries) were studied in the rat olfactory bulb. The density of blood vessels increased significantly over the second ten-day period of postnatal development. Electron microscopy revealed that blood vessels developed from solid cords of cells with thick endothelial cells, slit-like lumina and ill-defined lamina. The majority of these vessels became luminized during the second ten-day period and were characterized by patent lumina, well defined basal lamina and attenuated endothelial cells.     

Expression Sites of Colligin 2 in Glioma Blood Vessels

In a previous study using state-of-the-art proteomic techniques, we identified colligin 2 (HSP47) as a glioma blood vessel-specific protein. In the present study we precisely localized the expression of colligin 2 in the blood vessels of diffusely infiltrating gliomas and relate the expression to the distinct cellular components of the vessels by using multiple immunolabeling and confocal microscopy. We grouped the glioma blood vessels into morphological categories ranging from normal looking capillaries to vessels with hypertrophic and sclerotic changes. The expression patterns of various markers of endothelial and pericytic differentiation were correlated with the position of the cells in the vessels and the expression of colligin 2. We found that colligin 2 is expressed in all categories of glioma blood vessels in cells with endothelial and pericytic lineage. Expression of colligin 2 was also found in cells scattered around blood vessels and in few glial fibrillary acidic protein-positive cells within the blood vessels. There is overlap in the expression of colligin 2 and the collagens type I and IV for which colligin 2 is a chaperon. We conclude that colligin 2 is expressed in all cellular components of glioma blood vessels and may serve as a general marker for active angiogenesis.     

Development of anti-atherosclerotic tissue-engineered blood vessel by A20-regulated endothelial progenitor cells seeding decellularized vascular matrix

To investigate whether decellularized vascular tissues and A20-regulated endothelial progenitor cells can be used for constructing a transgenic tissue-engineered blood vessel with anti-atherosclerotic vascular stenotic properties. A20 gene-transfected endothelial progenitor cells differentiated endothelial cells and smooth muscle cells attached to and migrated into the decellularized porcine vascular scaffolding in a bioreactor. The histology of the conduits revealed viable and layered tissue. Scanning electron microscopy showed confluent, homogeneous tissue surfaces. The mechanical strength of the pulsed constructs was similar to that of the human artery. In vivo, the A20 gene-transfected tissue-engineered blood vessels were transplanted into the carotid artery of a rat for 6 months. Blood vessel xenotransplantation caused hyperacute rejection; all transplanted control blood vessels were completely rejected, but A20-transfected tissue-engineered blood vessels demonstrated good flow on implantation, and remained open for 6 months postoperatively, as assessed by Doppler. The HE stain demonstrated that the vessels were patent, without evidence of stenosis or dilatation after 6 months. These results demonstrate that transgenic tissue-engineered blood vessels have long-term patency and unique anti-stenotic properties.     

Endoglin (CD105) expression in angiogenesis of colon cancer: analysis using tissue microarrays and comparison with other endothelial markers

Some markers of angiogenic endothelial cells are emerging as targets of cancer therapy. The present study compares the expression of CD105 with that of other endothelial markers in all tissue layers during the development of colon cancer. We immunohistochemically analyzed the expression of the colon adenoma–carcinoma sequence by endothelial cells using a panel of eight endothelial markers. We examined sections from endoscopic mucosal resection and surgical resection of tubular adenoma (n=31), carcinoma in adenoma (n=11), and adenocarcinoma (n=34). Cylindrical cores were punched out from donor paraffin blocks of normal mucosa adjacent to tumors, from tumor lesions of mucosa, submucosa, muscularis propria, subserosa, and serosa, and from lymph node metastases. CD31 (PECAM-1) was universally expressed in the blood vessels of adenoma–carcinoma lesions as well as in normal mucosal vessels (80–95%), with no significant differences. In contrast, cancer-associated blood vessels (up to 80%) and cancer cells themselves expressed high levels of CD105. In normal mucosa, CD105 was weakly expressed in endothelial cells of capillaries (≦21%), and significant differences in its expression in endothelial cells between the normal mucosa and adenoma, carcinoma in adenoma, and adenocarcinoma were found. Flt-1, Flk-1, transforming growth factor-β1, transforming growth factor-β receptor II, and CD44 were strongly expressed in the cancer cells but were not expressed in the blood vessels. Vascular endothelial growth factor was expressed at <30% in the blood vessels of adenoma, carcinoma in adenoma, and carcinoma. Moreover, this study provided evidence that CD105 was expressed exclusively in endothelial blood vessels by double immunostaining of CD105 and D2-40. The present study shows that de novo blood vessels of colon cancer specifically express CD105. These findings provide the basis for novel antiangiogenic cancer therapies.     

The pathogenesis of vascular changes in erythema nodosum-like lesions of Beh?et's syndrome: an electron microscopic study

The probable sequence of microvascular changes affecting endothelial cells in erythema nodosum-like lesions was examined by electron microscopy in 18 patients with typical Beh?et's syndrome. Dark endothelial cells in the superficial and deep dermis exhibited degeneration with contraction changes. Consequently, degenerated endothelial cells showed nuclear and cytoplasmic condensation, vacuolization in the cytoplasm, and rich ribosomes. Moreover, blood vessels which were enveloped by cuffs of lymphocytes simultaneously exhibited both endothelial cell hypertrophy and endothelial cell necrosis. The implied associations between perivascular lymphocytic cuffs and blood vessels exhibiting endothelial cell alterations indicate that microvascular changes in erythema nodosum-like lesions may be closely associated with the delayed-type hypersensitivity reaction.     

New vessel formation after surgical brain injury in the rat's cerebral cortex II. Formation of the blood vessels distal to the surgical injury

We investigated the features of newly formed blood vessels after surgical brain injury of the rat's cerebral cortex distal to the operated region. We document the process of split mature blood vessels by an endothelial bridge and morphological features of newly formed vessels. We did not observe a disruption of brain parenchyma. The endothelial lining in vessels was complete. The morphological features of the endothelial cells and basement membrane show that non-sprouting angiogenesis takes place distally to the surgical injury.