血管内皮祖细胞的研究进展

在胚胎发育过程中，血管系统的建立始于两种方式：血管发生和血管新生。传统理论认为血管新生即是出生后血管发生的代名词。然而，近的来发现循环中存在骨髓来源的血管内皮祖细胞，并与出生后血管发生密切相关，具有重要的生理、病理意义。这不仅拓展了干细胞的研究，也为缺血性疾病和肿瘤的治疗提供了新策略。本文简述了血管内皮祖细胞的来源、细胞表面标志、生物学特性、生理病理意义及其临床应用前景。     

内皮祖细胞促进血管发生及新骨生成辅助治疗骨缺损

文题释义：内皮祖细胞：是血管内皮细胞的前体细胞,可在生理或病理因素刺激下,从骨髓动员到外周血参与损伤血管的修复,在血管内皮再生中发挥着重要作用。血管发生：在胚胎发育时从中胚层起始,由成血管细胞发育成血管内皮细胞并最终形成血管的过程,这是血管“从无到有”的一个生物学过程。 摘要背景：骨折是临床常见的骨科疾病,虽然大多数骨折可以通过坚强内固定等手术治疗实现一期愈合,但仍有相当比例的骨折愈合不良,最终导致骨缺损,而骨缺损部位的血管新生对骨缺损的修复起到至关重要的作用。基于内皮祖细胞促进组织血管发生的能力,其对骨再生和修复的辅助作用逐渐成为学界关注的焦点。目的：综述骨缺损疾病中使用内皮祖细胞促进血管发生及新骨生成的研究进展。方法：遵循PRISMA指南,检索CNKI、万方数据库和PubMed数据库1986至2019年期间关于内皮祖细胞辅助治疗骨缺损的动物实验、临床试验及其机制的文章,检索词分别为“内皮祖细胞,血管生成,血管发生,治疗,骨缺损”“endothelial progenitor cells (EPCs),angiogenesis,vasculogenesis,therapy/treatment,bone defect”,最后选择58篇文章纳入结果分析。结果与结论：①骨缺损时可以促进内皮祖细胞的激活与归巢;②内皮祖细胞可以促进血管发生;③内皮祖细胞是通过促进血管发生进而促进骨再生的;④将内皮祖细胞辅助治疗骨缺损推广至临床应用目前尚存在一些问题有待解决;⑤需要通过进行更多的临床试验,并且进一步深入研究内皮祖细胞参与血管发生的确切机制,为将来的临床应用提供数据支持,给大量骨缺损致残患者带来更好的治疗。ORCID: 0000-0001-5481-3865(冯源)中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程     

吡格列酮促进大鼠骨髓内皮祖细胞的增殖

背景：内皮祖细胞具有增殖、迁移和分化为内皮细胞的特征,对冠状动脉硬化性心脏病及糖尿病心血管并发症的发生、发展可能起着重要作用。 目的：探讨选择性过氧化物酶体增殖物激活受体γ激动剂吡格列酮对大鼠骨髓内皮祖细胞增殖的影响及相关机制。 方法：①采用密度梯度离心法和差速贴壁法培养大鼠骨髓内皮祖细胞,置于含0,1,10,50,100,200 μmol/L吡格列酮的培养基中培养,观察吡格列酮促进内皮祖细胞增殖的最佳浓度。②将培养7 d的内皮祖细胞随机分5组：对照组加含二甲基亚砜的培养液;吡格列酮组加入50 μmol/L吡格列酮;PPAR-γ拮抗剂组加入50 μmol/L吡格列酮及10 μmol/L过氧化物酶体增殖物激活受体γ拮抗剂GW9662;PI3K/Akt阻滞剂组加入50 μmol/L吡格列酮及50 μmol/L磷脂酰肌醇3-激酶/蛋白激酶B通道阻滞剂Wortmannin;ERK阻滞剂组加入50 μmol/L吡格列酮及20 μmol/L细胞外调节蛋白激酶通道阻滞剂PD98059,观察不同组内皮祖细胞的增殖情况。 结果与结论：倒置显微镜下见培养前4 d细胞增殖不明显,第5-10天迅速增殖,并可见细胞集落及线状结构形成,第10天可达80%融合。培养第7天的内皮祖细胞具有吞噬Dil标记的乙酰化低密度脂蛋白和FITC标记的荆豆凝集素1的功能。10-200 μmol/L的吡格列酮均可明显促进内皮祖细胞的增殖(P < 0.01),以50 μmol/L吡格列酮的作用最明显。进一步阻断相关信号通路发现,Wortmannin和GW9662可明显拮抗吡格列酮的促细胞增殖作用,而PD98059对吡格列酮的作用无影响。说明吡格列酮促进大鼠骨髓内皮祖细胞增殖的作用是通过磷脂酰肌醇3-激酶/蛋白激酶B信号通路介导的。     

Notch signaling and the emergence of hematopoietic stem cells

The hematopoietic stem cell (HSC) is able to give rise to all blood cell lineages in vertebrates. HSCs are generated in the early embryo after two precedent waves of primitive hematopoiesis. Canonical Notch signaling is at the center of the complex mechanism that controls the development of the definitive HSC. The successful in vitro generation of hematopoietic cells from pluripotent stem cells with the capacity for multilineage hematopoietic reconstitution after transplantation requires the recapitulation of the most important process that takes place in the hemogenic endothelium during definitive hematopoiesis, that is the endothelial-to-hematopoietic transition (EHT). To meet this challenge, it is necessary to thoroughly understand the molecular mechanisms that modulate Notch signaling during the HSC differentiation process considering different temporal and spatial dimensions. In recent years, there have been important advances in this field. Here, we review relevant contributions describing different genes, factors, environmental cues, and signaling cascades that regulate the EHT through Notch interactions at multiple levels. The evolutionary conservation of the hematopoietic program has made possible the use of diverse model systems. We describe the contributions of the zebrafish model and the most relevant ones from transgenic mouse studies and from in vitro differentiated pluripotent cells.     

Induction of similar features of apoptosis in human and bovine vascular endothelial cells treated by 7-ketocholesterol

Cholesterol oxides have numerous cytotoxic effects and those oxidized in the C7 position have been shown to induce apoptosis in bovine aortic endothelial cells (BAEC). The aim of the present study was to determine whether apoptosis also occurs in human vascular endothelial cells (HUVEC) treated with 7-ketocholesterol. To this end, cultured BAEC and HUVEC were incubated for 48 h with 7-ketocholesterol (concentration range 5–80 μg/ml) and the characteristics of cell death were assessed by various methods: counting of adherent and non-adherent cells; analysis of DNA fragmentation pattern; and morphological study by light, fluorescence, and electron microscopy. The 7-ketocholesterol treatment was accompanied by a decrease in the number of adherent cells and an increase in the number of non-adherent cells. Apoptotic cells, recognized by fragmented and/or condensed nuclei after staining with Hoechst 33342 or Giemsa, were mainly detected among non-adherent cells, and agarose gel electrophoresis revealed a typical internucleosomal DNA fragmentation among 7-ketocholesterol-treated cells. The DNA fragmentation was no longer detected when HUVEC and BAEC were simultaneously incubated with 0·5 mmol/l zinc chloride, which is known to inhibit Ca²⁺/Mg²⁺-dependent endonucleases. Finally, the ultrastructural abnormalities observed by electron microscopy in both 7-ketocholesterol-treated HUVEC and BAEC were remarkably similar and were mainly characterized by condensed chromatin, altered mitochondria, disturbed organization of the cytoskeleton, and vacuoles containing myelin figures and/or cell debris; apoptotic bodies were also frequently detected. It is concluded that 7-ketocholesterol constitutes a potent inducer of apoptosis in endothelial vascular cells of both bovine and human origin, suggesting that cholesterol oxides may be involved in the early steps of the atherosclerotic process in humans. © 1997 John Wiley & Sons, Ltd.     

胰岛素对人肝癌HepG2细胞体外诱导人脐静脉内皮细胞血管形成能力的影响

目的:探讨胰岛素对人肝癌细胞系HepG2体外诱导人脐静脉内皮细胞(HUVECs)血管形成能力的影响及其可能机制。方法:用含不同浓度胰岛素的完全培养基预培养肝癌细胞系HepG2制备条件培养基;应用预铺Matrigel基质胶的Transwell小室检测不同组条件培养基对HUVECs迁移能力的影响;运用CCK-8方法及EdU细胞增殖实验检测不同组条件培养基对HUVECs增殖能力的影响;运用内皮细胞成管实验检测不同组条件培养基对HUVECs成血管能力的影响;同时应用RT-PCR检测不同胰岛素浓度培养的HepG2细胞中血管内皮生长因子(VEGF)121、VEGF165、环氧化酶2(COX-2)的转录水平。结果:在一定浓度范围内,HepG2细胞对HUVECs的侵袭迁移能力、增殖能力的影响,对HUVECs的成血管能力的影响,对HepG2细胞VEGF121、VEGF165、COX-2转录水平的影响,均分别与胰岛素浓度呈正相关。结论:在一定浓度范围内,胰岛素可能通过上调HepG2细胞中VEGF121、VEGF165、COX-2的表达水平促进HepG2细胞诱导HUVECs血管形成能力。     

The F‐prostaglandin receptor is a novel marker for tumor endothelial cells in renal cell carcinoma

Tumor angiogenesis is necessary for tumor progression and metastasis; therefore, tumor blood vessels are potential therapeutic targets in anticancer therapy. We previously reported that tumor endothelial cells (TECs) exhibit different phenotypes compared with normal endothelial cells (NECs), and microarray analyses of mouse TECs and NECs have shown that several genes are upregulated in TECs compared with NECs. Among these genes, the expression levels of prostaglandin F receptor (PTGFR) mRNA, which encodes the prostaglandin F receptor (FP), were higher in TECs than in NECs. It has been reported that FP and its ligand, prostaglandin F_2α, are involved in tumor angiogenesis. However, there have been no reports of the expression of PTGFR in the tumor vessels of renal cell carcinoma (RCC). Thus, we isolated human TECs (hTECs) from RCCs. The expression levels of PTGFR mRNA were also upregulated in hTECs. In addition, immunostaining showed that the PTGFR was expressed in human tumor blood vessels in vivo. These findings suggested that PTGFR is a novel TEC marker and that it may be a novel target for antiangiogenic therapy for RCC.     

Lack of correlation between vascular endothelial growth factor production and endothelial cell proliferation in the human endometrium.

The role of vascular endothelial growth factor (VEGF) in endometrial angiogenesis was examined by measuring its production in human endometrial tissues from different stages of the menstrual cycle and relating these data to endothelial cell proliferation in the same tissues. Conditioned medium was collected from explant, and separated glandular epithelial and stromal cells cultured from 24 normal human endometrial biopsies and VEGF measured by enzyme-linked immunosorbent assay (ELISA). Immunohistochemistry was also used to assess VEGF and the percentage of proliferating microvessels in the samples. Wide variation in results between individual endometrial samples at each stage of the menstrual cycle was observed for all parameters measured. There was no significant difference in VEGF secretion by explant, glandular epithelial or stromal cell cultures across the menstrual cycle, or in the percentage of proliferating vessels. VEGF immunostaining in the stroma was elevated during the early proliferative stage (P = 0.03). Epithelial cells secreted more VEGF than stromal cells (1.76 +/- 0.46 versus 0.46 +/- 0.06 ng per 10(5) cells; P = 0.002). There was no correlation between VEGF secreted by cultured explants, epithelial or stromal cells, VEGF immunostaining and the proportion of proliferating microvessels. These results show that the majority of endometrial VEGF is produced by glands, but neither total glandular nor stromal VEGF is correlated with endometrial endothelial cell proliferation. There is still no clear understanding on the regulation of human endometrial angiogenesis.     

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。     

Infantile hemangioma is a proliferation of beta 4-negative endothelial cells adjacent to HLA-DR-positive cells with dendritic cell morphology

Although hemangioma is referred as to the most common tumor in infancy, the underlying pathogenetic events and the biologic origin of this benign vascular neoplasm have remained obscure. By using immunohistochemistry on frozen sections of infantile hemangiomas, we show here that proliferating endothelial cells abundantly expressed alpha(v)beta(3) but lacked beta(4) integrins. Instead, regressing and involuting infantile hemangiomas due to treatment with IFN-alpha showed positive staining of beta(4) integrin, which might point to the angiogenic significance of beta(4) integrin in infantile hemangiomas. Moreover, immunofluorescence analysis revealed the existence of HLA-DR(+), mostly CD68(+) and partly DC-SIGN/CD209(+) cells with dendritic cell morphology in the intimate vicinity of hemangiomatous vessels. Such cells were also detected in the dermal microvascular unit in normal skin. The coupled occurrence of vascular structures and perivascular cells that were stained positive with markers of monocyte or macrophage or dendritic cells might suggest that the development of infantile hemangioma is a result of vasculogenesis, that is, the formation of primitive blood vessels from angioblasts, rather than of angiogenesis, that is, the sprouting of capillaries from preexisting vessels.     

Effects of defensin and lactoferrin on functional activity of endothelial cells <Emphasis Type="Italic">in vitro</Emphasis>

We studied the effects of antibacterial peptides and proteins (defensins and lactoferrins) on functional activity of endothelial cells in vitro: proliferative activity and adhesion of human endothelial ECV-304 cells to the matrix were evaluated. α-Defensin (NP-2) from rabbit neutrophils, total α-defensin (HNP 1-3) from human neutrophils, and lactoferrins from porcine neutrophils and human milk were studied. Defensins stimulated and lactoferrin in doses of 1–10 μg/ml inhibited proliferation and adhesion of endothelial cell. The stimulatory effect of defensins on proliferation and adhesion was reproduced in fibroblast culture. Lactoferrins did not modify proliferation of fibroblasts, but suppressed their adhesion. These data suggest that antibiotic proteins and peptides are prospective objects for the creation of drugs regulating angiogenesis. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 144, No. 9, pp. 306–309, September, 2007     

Electron microscopy of endothelial cells in culture: IV. Surface replicas

Summary Few techniques exist for applying the resolving power of the transmission electron microscope to examination of the surface plasma membrane of any cell type. In this paper methods are described for replicating the true outer surface of endothelial cells in culture and for preparing the replicas for examination in a transmission electron microscope.     

CXCR7 influences the migration of B cells during maturation

The atypical chemokine receptor CXCR7 binds the chemokines CXCL12 and CXCL11. The receptor is widely expressed and was shown to tune CXCR12‐induced responses of CXCR4. Here, the function of CXCR7 was examined at late stages of human B‐cell maturation, when B cells differentiate into Ab‐secreting plasmablasts. We identified two populations of CXCR7⁺ cells in tonsillar lymphocytes, one being presumably memory B cells or early plasmablasts (FSC^lowCD19⁺CD38^mid) and the other being plasmablasts or early plasma cells (FSC^highCD19⁺CD38⁺). CXCR7 is expressed on CD19⁺CD27⁺ memory B cells, on CD19⁺CD38⁺CD138^? and intracellular immunoglobulin high plasmablasts, but not on CD19⁺CD138⁺icIg^high plasma cells. The differential expression pattern suggests a potential contribution of the scavenger receptor in final B‐cell maturation. On in vitro differentiating B cells, we found a marked inverse correlation between CXCR7 and CXCR5 cell surface levels, whereas expression of CXCR4 remained almost constant. Migration assays performed with tonsillar mononuclear cells or in vitro differentiated cells revealed that inhibition of CXCR7 markedly increases chemotaxis toward CXCL12, especially at late stages of B‐cell maturation. Chemotaxis was attenuated in the presence of CXCR4 antagonists, confirming that migration is CXCR4 mediated. Our findings unequivocally demonstrate a novel role for CXCR7 in regulating the migration of plasmablasts during B‐cell maturation.     

辛伐他汀对香烟烟雾提取物诱导的人脐静脉内皮细胞表达sEPCR和mEPCR的影响

目的: 研究辛伐他汀对香烟烟雾提取物(CSE)诱导的人脐静脉内皮细胞(HUVECs) 表达可溶性内皮细胞蛋白C受体(sEPCR)和膜联内皮细胞蛋白C受体(mEPCR)的干预作用。方法: 体外培养的4~6代HUVECs 随机分为对照组、5%CSE组、不同浓度辛伐他汀组及辛伐他汀干预组,辛伐他汀组分别加入50、100、200 μmol/L辛伐他汀液孵育24 h,辛伐他汀干预组先以50、100、200 μmol/L辛伐他汀预处理细胞2 h,再与5%CSE孵育24 h。收集各组细胞及上清液,ELISA法检测上清液中sEPCR蛋白含量,实时定量PCR法检测各组细胞中mEPCR mRNA的表达。结果: (1)5%CSE组sEPCR蛋白含量高于对照组,mEPCR mRNA表达低于对照组,差异均有统计学意义(均P<0.05);(2)100 μmol/L与200 μmol/L辛伐他汀组sEPCR蛋白含量均高于对照组,低于5%CSE组,其mEPCR mRNA表达均低于对照组,高于5%CSE组,差异均有统计学意义(均P<0.05);(3)各辛伐他汀干预组sEPCR蛋白含量均低于5%CSE组,但高于对照组及相应浓度的辛伐他汀组;相反,各辛伐他汀干预组mEPCR mRNA表达均高于5%CSE组,低于对照组及相应浓度的辛伐他汀组,差异均有统计学意义(均P<0.05)。结论: 在体外,辛伐他汀通过上调HUVECs mEPCR mRNA的表达,降低sEPCR的分泌,对CSE介导的内皮细胞凝血功能障碍可能具有一定的改善作用。     

High expression of CD34-positive sinusoidal endothelial cells is a risk factor for hepatocellular carcinoma in patients with HCV-associated chronic liver diseases

CD34 has been widely used for the assessment of sinusoid-like neoangiogenesis in hepatocellular carcinoma (HCC). Recently, it was demonstrated that CD34-positive cells isolated from human peripheral blood differentiate into endothelial cells and contribute to neoangiogenesis in adults. We investigated the localization and the substantial role of CD34-positive endothelial cells in the liver with hepatitis C virus (HCV)--associated chronic liver diseases. Liver tissue sections obtained by biopsy from 56 patients with HCV-associated chronic liver diseases by were examined immunohistochemically using anti-CD34, anti-von Willebrand factor (vWF), and anti-vascular endothelial growth factor (VEGF) antibodies. CD34 was stained in the sinusoid, showing dotty, linear, semicircular, or circular patterns. However, sinusoidal expression of vWF was not substantially identified in the same specimens, indicating the existence of sinusoidal CD34-positive but vWF-negative endothelial cells. We classified these cells as CD34 LI and found that CD34 LI was correlated with the expression of VEGF. Among 34 patients with advanced-stage disease, the cumulative incidence of HCC was significantly higher in patients with CD34 LI >or= 12 (n = 16) than in those with CD34 LI < 12 (n = 18; P = .009). Moreover, among several clinicopathologic risk factors, CD34 LI could be recognized as an independently significant factor for development of HCC (relative risk, 7.36; P = .019). We conclude that CD34-positive endothelial cells are regulated by several factors, such as VEGF, and might play a substantial role in hepatocarcinogenesis. Furthermore, high expression of CD34-positive sinusoidal endothelial cells is a risk factor for HCC in patients with HCV-associated chronic liver diseases.