Characteristics of Ex Vivo Expansion of Endothelial Progenitor Cells

Summary： The characteristics for the ex vivo expansion of the endothelial progenitor cells （EPCs） were explored, CD34^＋ cells were selected from umbilical cord blood mononuclear cells （MNC） by MiniMACS system, expanded under the same conditions as those for total MNC, coincubation of CD34^＋ and CD34 from the same donor for EPCs. In addition, the effects of vessel endothelial growth factor （VEGF） and passage on cell differentiation, expansion kinetics and apoptosis were examined, EPCs were determined and quantified by immunocytochemistry and flow cytometry, The results showed that both coculture of CD346＋ and CD34^- and total MNC led to a significant increase in the expansion of CD34^＋ cells as compared with CD34 enrichment （P〈0.05）. There was a tendency toward decreased apoptosis in cultures when early passage was performed immediately after cord like structures appeared. VEGF had no significant effect on apoptosis （P〉0.05）, These differentiated EPCs were positive for CD34^＋, von Willebrand factor （vWF）, KDR, CD31 staining and phagocytized acetylated low-density lipoprotein （LDL）. CD34^＋ cells accounted for （68.2±6,3） % of attaching （AT） cells at day 7 of culture. It was suggested the most efficient method to ex vivo expansion of EPCs was coculture of CD34^＋ and CD34^- or total MNC. Early passage makes cell apoptosis rate decrease. VEGF had no significant effect on ex vivo expansion of EPCs.

A familiar stranger:CD34 expression and putative functions in SVF cells of adipose tissue

Human adipose tissue obtained by liposuction is easily accessible and an abundant potential source of autologous cells for regenerative medicine applications. After digestion of the tissue and removal of differentiated adipocytes, the so-called stromal vascular fraction (SVF) of adipose, a mix of various cell types, is obtained. SVF contains mesenchymal fibroblastic cells, able to adhere to culture plastic and to generate large colonies in vitro , that closely resemble bone marrow-derived colony forming units-fibroblastic, and whose expanded progeny, adipose mesenchymal stem/stromal cells (ASC), show strong similarities with bone marrow mesenchymal stem cells. The sialomucin CD34, which is well known as a hematopoietic stem cell marker, is also expressed by ASC in native adipose tissue but its expression is gradually lost upon standard ASC expansion in vitro . Surprisingly little is known about the functional role of CD34 in the biology and tissue forming capacity of SVF cells and ASC. The present editorial provides a short introduction to the CD34 family of sialomucins and reviews the data from the literature concerning ex- pression and function of these proteins in SVF cells and their in vitro expanded progeny.

Enhancing endothelial progenitor cell for clinical use

Circulating endothelial progenitor cells(EPCs) have been demonstrated to correlate negatively with vascularendothelial dysfunction and cardiovascular risk factors. However, translation of basic research into the clinical practice has been limited by the lack of unambiguous and consistent definitions of EPCs and reduced EPC cell number and function in subjects requiring them for clinical use. This article critically reviews the definition of EPCs based on commonly used protocols, their value as a biomarker of cardiovascular risk factor in subjects with cardiovascular disease, and strategies to enhance EPCs for treatment of ischemic diseases.

Effects of endostatin on expression of vascular endothelial growth factor and its receptors and neovascularization in colonic carcinoma implanted in nude mice

AIM:To investigate the antiangiogenic effects of endostatin on colonic carcinoma cell line implanted in nude mice and its mechanism. METHODS:Nude mice underwent subcutaneous injection with LS-174t colonic carcinoma cell line to generate carcinoma and were randomly separated into two groups.Mice received injection of vehicle or endostatin every day for two weeks. After the tumor was harvested,the tumor volumes were determined,and the expressions of CD34,VEGF and FIk-1 were examined by immunohistochemical method. RESULTS:Tumor volume was significantly inhibited in the endostatin group(84.17%)and tumor weight was significantly inhibited in the endostatin group(0.197±0.049) compared to the control group(1.198±0.105)(F=22.56, P=0.001),microvessel density(MVD)was significantly decreased in the treated group(31.857±3.515)compared to the control group(100.143±4.290)(F=151.62,P<0.001). Furthermore,the expression of FIk-1 was significantly inhibited in the treated group(34.29%) ompared to the control group(8.57%)(X^2=13.745,P=0.001).However no significant decrease was observed in the expression of vascular endothelial growth factor(VEGF)between these two groups(X^2=0.119,P=0.730). CONCLUSION:Endostatin can inhibit tumor growth and angiogenesis by blocking Vegf/FIk-1 pathway.This experiment provides the theory basis for developing a new anti-carcinoma drug through studying the properties of anti-angiogenesis inhibitors.

Distinctive effects of CD34- and CD133-specific antibody-coated stents on re-endothelialization and in-stent restenosis at the early phase of vascular injury

It is not clear what effects of CD34-and CD133-specific antibody-coated stents have on reendothelialization and in-stent restenosis(ISR)at the early phase of vascular injury.This study aims at determining the capabilities of different coatings on stents(e.g.gelatin,anti-CD133 and anti-CD34 antibodies)to promote adhesion and proliferation of endothelial progenitor cells(EPCs).The in vitro study revealed that the adhesion force enabled the EPCs coated on glass slides to withstand flow-induced shear stress,so that allowing for the growth of the cells on the slides for 48 h.The in vivo experiment using a rabbit model in which the coated stents with different substrates were implanted showed that anti-CD34 and anti-CD133 antibody-coated stents markedly reduced the intima area and restenosis than bare mental stents(BMS)and gelatin-coated stents.Compared with the anti-CD34 antibody-coated stents,the time of cells adhesion was longer and earlier present in the anti-CD133 antibody-coated stents and anti-CD133 antibody-coated stents have superiority in re-endothelialization and inhibition of ISR.In conclusion,this study demonstrated that anti-CD133 antibody as a stent coating for capturing EPCs is better than anti-CD34 antibody in promoting endothelialization and reducing ISR.

电针对局灶脑缺血/再灌注大鼠骨髓及外周血CD34^+内皮祖细胞的影响

目的:观察电针对局灶脑缺血/再灌注大鼠骨髓及外周血CD 34+内皮祖细胞(EPCs)数量、磷酸化蛋白激酶B(p-AKT)表达的影响,探讨电针动员骨髓CD 34+EPCs入血,促进脑缺血修复的机制。方法:雄性SD大鼠随机分为假手术组、模型组、电针组。采用线栓法制备局灶脑缺血/再灌注大鼠模型,局灶脑缺血2h后将各组分为再灌注12、24、48h3个时间点,每个时间点12只大鼠。取大鼠"百会"穴及左侧"四关"穴("合谷"/"太冲")为电针穴位,刺激时间30min,每日1次。采用神经行为学评分法评价大鼠神经功能缺损情况,流式细胞术检测骨髓及外周血CD 34+EPCs数量,Western blot法检测骨髓p-AKT蛋白的表达。结果:模型组再灌注后各时间点均有不同程度的神经功能缺损,电针可明显改善大鼠再灌注后48h神经功能评分(P<0.05)。与假手术组比较,模型组各时间点骨髓及外周血CD 34+EPCs数量及骨髓p-AKT蛋白的表达明显增多(P<0.01,P<0.05);与模型组比较,电针组再灌注后各时间点外周血CD 34+EPCs数量及骨髓p-AKT蛋白的表达亦明显增多(P<0.05,P<0.01),同时电针组再灌注后12、24h骨髓CD 34+EPCs数量相对模型组明显上调(P<0.05,P<0.01)。结论:电针可上调局灶脑缺血/再灌注大鼠骨髓及外周血CD 34+EPCs数量,促进骨髓CD 34+EPCs动员入血,其作用可能与电针进一步激活骨髓磷脂酰肌醇-3-激酶/AKT通路相关。

Cold water swimming pretreatment reduces cognitive deficits in a rat model of traumatic brain injury

A moderate stress such as cold water swimming can raise the tolerance of the body to potentially injurious events. However, little is known about the mechanism of beneficial effects induced by moderate stress. In this study, we used a classic rat model of traumatic brain injury to test the hypothesis that cold water swimming preconditioning improved the recovery of cognitive functions and explored the mechanisms. Results showed that after traumatic brain injury, pre-conditioned rats（cold water swimming for 3 minutes at 4℃） spent a significantly higher percent of times in the goal quadrant of cold water swim, and escape latencies were shorter than for non-pretreated rats. The number of circulating endothelial progenitor cells was significantly higher in pre-conditioned rats than those without pretreatment at 0, 3, 6 and 24 hours after traumatic brain injury. Immunohistochemical staining and Von Willebrand factor staining demonstrated that the number of CD34~＋ stem cells and new blood vessels in the injured hippocampus tissue increased significantly in pre-conditioned rats. These data suggest that pretreatment with cold water swimming could promote the proliferation of endothelial progenitor cells and angiogenesis in the peripheral blood and hippocampus. It also ameliorated cognitive deficits caused by experimental traumatic brain injury.

乳腺癌患者外周血中内皮祖细胞检测的临床意义

目的探讨乳腺癌患者外周血中内皮祖细胞(EPCs)检测的临床意义。方法采用前瞻性研究方法,收集2014年3月至2015年3月吉林省肿瘤医院收治的、病理学证实的70例浸润性乳腺导管癌患者、61例乳腺纤维腺瘤患者和68名健康人的外周血,利用流式细胞术检测EPCs[CD34、CD133和血管内皮生长因子受体(VEGFR)-2阳性细胞]水平。采用Fisher确切概率检验和KruskalWallis H检验比较3组间EPCs阳性率及其表面标志物CD34、CD133和VEGFR-2表达量的差异,并用Fisher确切概率检验分析乳腺癌患者EPCs阳性率与临床病理特征的关系;采用t检验比较不同临床分期和不同淋巴结转移状态患者间EPCs表面标志物CD34、CD133和VEGFR-2表达量的差异。结果在乳腺癌患者、乳腺纤维腺瘤患者和健康人外周血中,EPCs阳性率及其表面标志物CD34、CD133和VEGFR-2表达量的差异均有统计学意义(χ~2=12. 811,P<0. 001; F=15. 275,P<0. 001);健康人及乳腺纤维腺瘤组均未检测到EPCs,组间两两比较显示,EPCs表面标志物CD34、CD133和VEGFR-2在乳腺癌患者外周血中的表达量[M(P25～P75):0. 006%(0. 003%～6. 008%)]明显高于健康人及乳腺纤维腺瘤患者(P=0. 002、0. 003),乳腺癌组EPCs阳性率也显著高于健康人及乳腺纤维腺瘤患者[11. 4%(8/70)分别比0(0/68)、0(0/61),P=0. 006、0. 007]。但EPCs阳性率与乳腺癌患者的年龄、ER、PR和HER-2状态均无关(P均>0. 050)。进一步分析EPCs阳性的8例乳腺癌患者临床资料后发现,Ⅰ期患者(n=4)外周血中EPCs表面标志物CD34、CD133和VEGFR-2的表达量明显低于Ⅱ～Ⅳ期患者(n=4)[(0. 300±0. 162)%比(1. 130±0. 318)%,t=4. 640,P=0. 004],而淋巴结转移者(n=4) EPCs表面标志物CD34、CD133和VEGFR-2的表达量明显高于未转移者(n=4)[(1. 062±0. 424)%比(0. 370±0. 287)%,t=2. 700,P=0. 040]。结论乳腺癌患者外周血中EPCs表面标志CD34、CD133和VEGFR-2表达水平较高,其可能是一种潜在的生物标志物和治疗靶点。