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超声及微泡介导干细胞治疗心肌梗死的研究进展

2017-09-22张杰穆玉明

中国医药导报 2017年23期
关键词:微泡超声心肌梗死

张杰+穆玉明

[摘要] 利用干细胞修复梗死心肌的方法极具潜力,但单纯外源性移植存在免疫排斥、病原体传播、储存、包装等问题,更重要的是,干细胞无法高效归巢到靶区。而超声靶向微泡破坏技术凭借其非侵入性、低免疫原性、可重复性、靶向性等优点成为一种新型基因传递体系,在干细胞趋化和基因治疗的研究中被广泛应用。本文就超声及微泡辅助干细胞治疗心肌梗死的方法进行综述。

[关键词] 超声;微泡;干细胞治疗;心肌梗死

[中图分类号] R542.2 [文献标识码] A [文章编号] 1673-7210(2017)08(b)-0029-04

[Abstract] The method of using stem cells to repair infarcted myocardium has great potential. But there are a series of questions with simple exogenous transplantation, such as immunological rejection, transmission of pathogens, storage, packing and more, the stem cells can′t home to the targeted area efficiently. As a novel gene delivery system, ultrasound-targeted microbubble destruction has been widely used for recruiting stem cells and gene therapy for its advantages of noninvasiveness, low immunogenicity, repeatability, spatial target specificity, etc. This article reviewes the methods of ultrasound and microbubble mediated stem cell in the treatment of myocardial infarction.

[Key words] Ultrasound; Microbubble; Stem cell therapy; Myocardial infarction

隨着全球经济的迅猛发展,城市化和生活方式的改变使心血管疾病患病率与日俱增,尽管新的研究成果已经开始用于诊断和治疗,但在很多国家,心血管疾病仍是主要的致死原因[1],因此,利用干细胞替代、修复和改善受损心肌的方法前景广阔[2]。事实上,心肌梗死后机体本身释放的趋化因子可诱导外周骨髓干细胞自发归巢,修复受损的心肌组织,通过外力作用放大此种效应无疑可起到治疗心肌梗死的作用。但是,“轴向移动”效应[3]使毛细血管中的干细胞主要位于血管中轴附近,严重限制了干细胞向内皮组织的靶向黏附能力。

自Imada等[4]首次利用超声联合微泡干预的方法增效干细胞移植治疗缺血骨骼肌以来,超声微泡开始在细胞、基因治疗方面倍受关注。超声辐照微泡通过声孔效应使周围组织的生物屏障通透性增加,有利于移植细胞向缺血区的迁移和浸润;同时使血管内容物外渗产生炎性反应、通过旁分泌作用增加内源性细胞因子的产生,改变局部微环境,促进新生血管形成,促进干细胞的归巢、黏附、增殖、分化,增强移植干细胞的增殖活性和靶向性,修复受损心肌组织[5-7]。因此,本文对超声及微泡介导干细胞治疗心肌梗死的方法进行综述。

1 超声、微泡对心肌梗死组织预处理后行干细胞移植

鉴于心肌微环境在干细胞移植中的决定性作用[8],许多研究者将超声辐照微泡对心肌微环境的影响作为研究重点,在经冠脉干细胞移植前利用超声靶向微泡破坏技术(ultrasound-targeted microbubble destruction,UTMD)对心梗组织预处理,通过刺激炎性反应、改变局部心肌微环境,促进骨髓间充质干细胞(bone marrow-derived mesenchymal stem cells,BMSCs)向心肌归巢、分化[9-11],同时促进归巢干细胞的存活[12],提高治疗效果。随着聚焦超声(focused ultrasound,FUS)的发展[13],Ghanem等[14]用发射能量较低的高强度聚焦超声介导的微泡刺激(highly focused ultrasound-mediated stimulation of microbubbles,fh-UMS)代替普通的UTMD,对大鼠梗死心肌预处理后经主动脉根部导管注射BMSCs增强了内皮细胞的靶向黏附能力,促进了干细胞移植。考虑到不同的超声辐照参数产生的生物学效应不同,较弱的炎性反应有助于干细胞的动员和归巢,但过度的炎症细胞浸润可能会使干细胞凋亡和坏死,不利于细胞治疗,Ling等[15]以犬为研究对象,利用不同参数UTMD对梗死心肌预处理后经冠状动脉注射间充质干细胞(mesenchymal stem cells,MSCs),证明此方法治疗心肌梗死的同时,亦得出一组较佳的超声辐照参数:频率1 Hz,脉冲超声强度1 W/cm2。通过对最佳超声辐照参数的研究,UTMD得到进一步的发展,通过改变局部心肌微环境,诱导干细胞归巢,增强了干细胞治疗心肌梗死的效果。

2 超声、微泡对干细胞预处理后行干细胞移植

随着UTMD的不断成熟,一些研究者开始对超声辐照微泡(ultrasound-exposed microbubbles,UM)预处理的干细胞进行移植,探究其对心肌梗死的治疗效果。经冠脉注射UM预处理的BMSCs较注射未预处理的BMSCs可明显增加向受损心肌归巢的干细胞数量,促进新生血管形成,改善心功能[16]。对BMSCs进行UM预处理可以促使BMSCs向基质细胞衍生因子-1(stromal derived factor-1,SDF-1)浓度迁移、向缺血的大鼠心肌靶向归巢[17-18],Gu等[19]检测BMSCs内CXCR4的转染和表达以及钙离子的含量,证明外源性移植经UM预处理的干细胞可增强干细胞移植效果,其机制可能与UM-钙离子-CXCR4轴有关。至此,超声及微泡介导干细胞治疗心肌梗死的研究层次得到提高。endprint

3 干细胞移植后注射微泡行超声辐照

将UTMD与干细胞移植相结合治疗心肌梗死的方法很多,为了探求一个最佳的结合方法,也有研究者对心肌梗死的新西兰兔经静脉MSCs移植后注射微泡进行超声辐照,发现此方法亦可诱导局部新生血管形成,改善心肌灌注,同时抑制心肌纤维化和心肌重构[20],改善心功能。通过进一步分析SDF-1/CXCR4的表达、计数向心梗区域归巢的MSCs,Li等[7]提出,此方法促使经静脉注射的MSCs向SD大鼠缺血心肌归巢的机制与UTMD上调SDF-1/CXCR4轴有关。超声及微泡介导干细胞治疗心肌梗死的作用通过SDF-1/CXCR4轴得到印证。

4 超声、微泡与其他方法相结合对干细胞预处理后进行移植

单纯UTMD介导干细胞移植的作用有限,众多研究者开始在体外将UTMD与其他方法相结合对干细胞进行预处理,共同促进干细胞移植。UTMD与去甲基化药物5-氮杂胞苷(5-Azacytine,5-Aza)联合应用,5-Aza诱导MSCs向心肌分化的效果增强[21];UTMD(t = 30 s,A = 0.6 W/cm2,MB = 106/mL)与低氧诱导(hypoxic preconditioning,HP)(1%O2,94%N2,5%CO2,24 h)相结合(HP-MB),SDF-1/CXCR4轴的表达上调,MSCs向心肌梗死区的趋化能力提高[22]。UTMD与其他方法联合应用预处理干细胞促进其归巢的作用得到证实。

5 超声辐照经修饰的微泡促进干细胞移植

除了联合其他方法对干细胞进行预处理外,对微泡进行修饰也可以提高移植效率:超声辐照NO微泡可通过增加SDF-1和血管内皮生长因子(vascular endothelial growth factor,VEGF)的表达促进经静脉注射的干细胞向大鼠梗死心肌归巢、诱导新生血管形成,改善心功能[23-24];利用UTMD将铜-微泡传递至新西兰兔缺血心肌,可通过激活铜相关低氧诱导转录因子(hypoxia-inducible transcription factor-1,HIF-1)重建BMSCs归巢的信号通路,促进经静脉注射的BMSCs归巢[25]。

6 超声辐照微泡-干细胞复合体促进干细胞移植

为了进一步提高干细胞移植的效率,Naaijkens等[26]将CD90抗体与CD54抗体同时偶联到微泡表面,制成干细胞-微泡复合体(stem bells),通过CD90抗体使双重靶向微泡与脂肪源性干细胞(adipose derived stem cells,ASCs)结合,通过抗ICAM-1的CD54抗体促使经静脉注射的ASCs向兔心肌梗死区靶向运动,进一步增强了干细胞移植的靶向性。Kokhuis等[27]则通过活体显微镜直接在鸡胚胎中对超声辐照stem bells产生的效应进行光学观察,证实了联合应用UTMD和stem bells定向传递干细胞的可行性和高效性:增加干细胞靶向归巢的同时将侵袭性降到最低,并在体外鉴定stem bells在超声暴露下的活性以及对声辐射的敏感性之后,在Wistar大鼠体内证实了超声辐照经静脉注射的stem bells来促进干细胞归巢的安全性[28]。至此,超声介导微泡-干细胞联合治疗心肌梗死以其较强的靶向性正吸引着越来越多的研究者。

7 UTMD介导的基因治疗促进内源性干细胞移植

除了干细胞移植效率的问题外,外源性干细胞移植还存在着分离、纯化、免疫排斥等问题,均限制了干细胞移植的应用。因此,促进内源性干细胞移植的研究应运而生。一些研究者[29-32]首先在体外证实,UTMD不但可提高基因转染效率,还能保持干细胞转染后的增殖活性和分化能力。在体内研究中,Du等[33]利用UTMD介導与功能恢复有关的GDF11[34]转染促进了老年大鼠自身内皮祖细胞(endothelial progenitorcells,EPCs)归巢和心脏干细胞(cardiac stem cells,CSCs)增殖,改善了心功能;Fujii等[35]将UTMD与VEGF、干细胞因子(stem cell factor,SCF)基因治疗相结合,通过基因转染促进C57BL/6小鼠自体干细胞[VEGF受体2+和SCF受体(c-kit)+]向心脏归巢,之后又通过重复治疗(至少6次)增强了治疗效果[36]。因其广阔的应用前景,UTMD介导基因转染促内源性干细胞归巢治疗心肌梗死的研究日益增多。

8 小结和展望

超声及微泡辅助干细胞移植治疗心肌梗死的效果已得到证实,是一种极具潜力的治疗方法。但迄今为止,UTMD的研究还只停留在体外和小动物模型等临床前实验的阶段,在靶基因选择、超声辐照参数、微泡浓度和成分以及微泡和干细胞或基因的比例等显著影响移植效率的重要方面[37]均无明确标准,考虑到安全性的问题,要将超声及微泡辅助干细胞移植的方法真正用于心肌梗死的临床治疗,仍需进一步研究。

[参考文献]

[1] Mozaffarian D,Benjamin EJ,Go AS,et al. Heart disease and stroke statistics—2015 update:a report from the American Heart Association [J]. Circulation,2015,131(4):e29-e322.

[2] Hao M,Wang R,Wang W. Cell therapies in cardiomyopathy:current status of clinical trials [J]. Anal Cell Pathol(Amst),2017,2017:9404057.

[3] Bayliss LE. The axial drift of the red cells when blood flows in a narrow tube [J]. J Physiol,1959,149:593-613.endprint

[4] Imada T,Tatsumi T,Mori Y,et al. Targeted delivery of bone marrow mononuclear cells by ultrasound destruction of microbubbles induces both angiogenesis and arteriogenesis response [J]. Arterioscler Thromb Vasc Biol,2005,25(10):2128-2134.

[5] Deng W,Chen QW,Li XS,et al. Bone marrow mesenchymal stromal cells with CD47 high expression via the signal transducer and activators of transcription signaling pathway preventing myocardial fibrosis [J]. Int J Clin Exp Pathol,2015,8(9):10555-10564.

[6] Liao YY,Chen ZY,Wang YX,et al. New progress in angiogenesis therapy of cardiovascular disease by ultrasound targeted microbubble destruction [J]. Biomed Res Int,2014, 2014:872984.

[7] Li L,Wu SZ,Liu Z,et al. Ultrasound-targeted microbubble destruction improves the migration and homing of mesenchymal stem cells after myocardial infarction by upregulating SDF-1/CXCR4:a pilot study [J]. Stem Cells Int,2015,2015:691310.

[8] Scuderi GJ,Butcher J. Naturally engineered maturation of cardiomyocytes [J]. Front Cell Dev Biol,2017,5:50.

[9] Song X,Zhu H,Jin L,et al. Ultrasound-mediated microbubble destruction enhances the efficacy of bone marrow mesenchymal stem cell transplantation and cardiac function [J]. Clin Exp Pharmacol Physiol,2009,36(3):267-271.

[10] Zhong S,Shu S,Wang Z,et al. Enhanced homing of mesenchymal stem cells to the ischemic myocardium by ultrasound-targeted microbubble destruction [J]. Ultrasonics,2012,52(2):281-286.

[11] Chang X,Liu J,Liao X,et al. Ultrasound-mediated microbubble destruction enhances the therapeutic effect of intracoronary transplantation of bone marrow stem cells on myocardial infarction [J]. Int J Clin Exp Pathol,2015, 8(2):2221-2134.

[12] Silva GV,Zheng Y,Quan X,et al. A novel strategy for increasing myocardial retention of stem cells delivered by intracoronary infusion in a porcine model of acute myocardial infarction [J]. Circulation,2011,124(21):A15663.

[13] Miller DB,O'Callaghan JP. New horizons for focused ultrasound (FUS)-therapeutic applications in neurodegenerative diseases [J]. Metabolism,2017,69(S):S3-S7.

[14] Ghanem A,Steingen C,Brenig F,et al. Focused ultrasound-induced stimulation of microbubbles augments site-targeted engraftment of mesenchymal stem cells after acute myocardial infarction [J]. J Mol Cell Cardiol,2009,47(3):411-418.

[15] Ling ZY,Shu SY,Zhong SG,et al. Ultrasound targeted microbubble destruction promotes angiogenesis and heart function by inducing myocardial microenvironment change [J]. Ultrasound Med Biol,2013,39(11):2001-2010.endprint

[16] Yin F,Battiwalla M,Ito S,et al. Bone marrow mesenchymal stromal cells to treat tissue damage in allogeneic stem cell transplant recipients:correlation of biological markers with clinical responses [J]. Stem Cells,2014,32(5):1278-1288.

[17] Purroy N,Abrisqueta P,Carabia J,et al. Co-culture of primary CLL cells with bone marrow mesenchymal cells,CD40 ligand and CpG ODN promotes proliferation of chemoresistant CLL cells phenotypically comparable to those proliferating in vivo [J]. Oncotarget,2015,6(10):7632-7643.

[18] Lourenco S,Teixeira VH,Kalber T,et al. Macrophage migration inhibitory factor-CXCR4 is the dominant chemotactic axis in human mesenchymal stem cell recruitment to tumors [J]. J Immunol,2015,194(7):3463-3474.

[19] Gu JY,Shi HF,Gao XL,et al. Effect of CXCR4 pretreated with ultrasound-exposed microbubbles on accelerating homing of bone marrow mesenchymal stem cells to ischemic myocardium in AMI rats [J]. Asian Pac J Trop Med,2015,8(9):766-771.

[20] Xu YL,Gao YH,Liu Z,et al. Myocardium-targeted transplantation of mesenchymal stem cells by diagnostic ultrasound-mediated microbubble destruction improves cardiac function in myocardial infarction of New Zealand rabbits [J]. Int J Cardiol,2010,138(2):182-195.

[21] 陳玲玲,尹立雪.超声辐照微泡介导5-氮杂胞苷诱导人骨髓间充质干细胞心肌样分化的实验研究[J].中华超声影像学杂志,2013,22(11):991-996.

[22] Li L,Wu S,Li P,et al. Hypoxic preconditioning combined with microbubble-mediated ultrasound effect on MSCs promote SDF-1/CXCR4 expression and its migration ability:an in vitro study [J]. Cell Biochem Biophys,2015,73(3):749-757.

[23] Bian Y,Tong J,Shen X,et al. Expernment study of ultrasound combined with nitric oxide microbubbles enhance the efficacy of mesenchymal stem cells transplantation in myocardial infarction and the probable mechanism [J]. Heart,2012,98(s2):E120.

[24] Tong J,Ding J,Shen X,et al. Mesenchymal stem cell transplantation enhancement in myocardial infarction rat model under ultrasound combined with nitric oxide microbubbles [J]. PLoS One,2013,8(11):e80186.

[25] Zheng L,Sun W,Sun X,et al. Recovery of mesenchymal stem cells homing to rabbit myocardial ischemic infarct area by Cu-microbubble treatment [J]. FASEB J,2015, 29(1):s670.3.

[26] Naaijkens B,Krijnen P,Bogaards S,et al. Directing stem cells to the infarcted heart using stem bells TM:introducing a novel technique using targeted microbubbles [J]. Circulation,2013,128(s22):A15053.

[27] Kokhuis TJ,Skachkov I,Naaijkens BA,et al. Intravital microscopy of localized stem cell delivery using microbubbles and acoustic radiation force [J]. Biotechnol Bioeng,2015,112(1):220-227.endprint

[28] Woudstra L,Krijnen PA,Bogaards SJ,et al. Development of a new therapeutic technique to direct stem cells to the infarcted heart using targeted microbubbles:stem bells [J]. Stem Cell Res,2016,17(1):6-15.

[29] Otani K,Yamahara K,Ohnishi S,et al. Nonviral delivery of siRNA into mesenchymal stem cells by a combination of ultrasound and microbubbles [J]. J Control Release,2009,133(2):146-153.

[30] Pu Z,You X,Xu Q,et al. Protein expression of mesenchymal stem cells after transfection of pcDNA3.1?-hVEGF by ultrasound-targeted microbubble destruction [J]. J Biomed Biotechnol,2011,2011:839653.

[31] Li P,Gao Y,Liu Z,et al. DNA transfection of bone marrow stromal cells using microbubble-mediated ultrasound and polyethylenimine:an in vitro study [J]. Cell Biochem Biophys,2013,66(3):775-786.

[32] Jin L,Li F,Wang H,et al. Ultrasound targeted microbubble destruction enhances gene transduction of adeno-associated virus in a less-permissive cell type,NIH/3T3 [J]. Mol Med Rep,2013,8(2):320-326.

[33] Du GQ,Shao ZB,Wu J,et al. Targeted myocardial delivery of GDF11 gene rejuvenates the aged mouse heart and enhances myocardial regeneration after ischemia-reperfusion injury [J]. Basic Res Cardiol,2017,112(1):7.

[34] Finkenzeller G,Stark GB,Strassburg S. Growth differentiation factor 11 supports migration and sprouting of endothelial progenitor cells [J]. J Surg Res,2015,198(1):50-56.

[35] Fujii H,Sun Z,Li SH,et al. Ultrasound-targeted gene delivery induces angiogenesis after a myocardial infarction in mice [J]. JACC Cardiovasc Imaging,2009,2(7):869-879.

[36] Fujii H,Li SH,Wu J,et al. Repeated and targeted transfer of angiogenic plasmids into the infarcted rat heart via ultrasound targeted microbubble destruction enhances cardiac repair [J]. Eur Heart J,2011,32(16):2075-2084.

[37] Zhang CB,Cao HL,Li Q,et al. Enhancement effect of ultrasound-induced microbubble cavitation on branched polyethylenimine-mediated VEGF(165) transfection with varied N/P ratio [J]. Ultrasound Med Biol,2013,39(1):161-171.endprint

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