磁性标记的小胶质细胞在大鼠脑内的MR示踪

目的 探讨超顺磁性氧化铁颗粒(SPIO)标记的小胶质细胞在正常大鼠及阿尔茨海默病(AD)大鼠体内移植后,MR活体示踪的可行性.方法 以日本血液凝集病毒包膜(HVJ-E)为标记载体,将SPIO标记的小胶质细胞经颈内动脉注入正常大鼠(5只)及AD大鼠动物模型(5只)体内,3 d后应用7.0 T MR行T2*序列扫描,并与脑组织切片组织化学染色结果对照.结果 在正常大鼠脑内,MRI可见数个点状的信号改变区,这些信号改变区散在地分布在脑内各处,脑组织切片显示铁颗粒标记细胞位置与信号改变部位一致.MRI能够检测到由数个标记细胞引起的信号强度的改变.在AD大鼠模型脑内,MRI可见β-淀粉样蛋白42(Aβ42)注射区信号强度明显下降,信号改变区面积较大.与之相比,生理盐水注射区信号改变的强度及面积均不如Aβ42注射区改变明显.Aβ42注射区的标记细胞数为(454±47)个/mm2,明显高于生理盐水注射区的标记细胞数(83±13)个/mm2(P<0.05).结论 MRI可作为一种非侵入性检测手段在活的动物体内追踪标记细胞,在AD细胞水平的治疗中具有一定临床应用前景.     

磁标记大鼠骨髓间充质干细胞活体内移植后向肝癌细胞趋向性迁移的研究

目的 探讨磁标记大鼠骨髓间充质干细胞(BMSCs)活体内移植后对大鼠肝细胞癌的趋向性迁移及其机制.方法 培养大鼠BMSCs,超顺磁性氧化铁粒子标记.制备大鼠肝癌模型24只,数字表法随机分为3组:实验组(n=12)经脾植入磁标记的BMSCs;对照组A(n=6)移植未标记的BMSCs;对照组B(n=6)不作任何处理.分别于移植前及移植后1、3、7和14 d行MR扫描,选用T_2*WI序列进行移植细胞的示踪并测量肿瘤组织与正常肝组织的信号强度的比值(SI/SI*),结果行单因素方差分析;取肿瘤组织、瘤旁正常肝组织行普鲁士蓝染色,分析BMSCs在体内的分布并与MR对照.结果 BMSCs的磁标记率为90%以上.移植后实验组T_2*WI显示肿瘤信号强度值明显减低,移植前及移植后1、3、7和14 d的SI/SI*值分别为3.18±0.21、1.98±0.20、2.38±0.28、2.70±0.25及3.16±0.24,差异有统计学意义(F=56.65,P<0.05);与移植前相比,1、3、7 d肿瘤信号强度的减低有统计学意义(t值分别为1.20、0.79、0.48,P值均<0.05).对照组移植前后各SI/SI*值差异无统计学意义(P>0.05).免疫组织化学显示实验组肿瘤边缘及内部有大量监染的普鲁士蓝阳性细胞分布,标记细胞在肿瘤内的分布与MR信号改变基本一致.对照组肿瘤组织普鲁士蓝染色均为阴性结果.结论 BMSCs在活体内对肝癌细胞有明显的趋向迁移特性,有望成为基因治疗肝细胞癌的载体.     

MRI评价骨髓问质干细胞治疗猪急性心肌梗死效果的实验研究

目的 应用MRI评价经冠状动脉途径移植猪自体骨髓间质干细胞(BM-MSCs)治疗急性心肌梗死(AMI)的治疗效果.方法 8月龄中华小型猪14只[(27±3)kg],平均分成移植组与对照组.胶圈套扎左前降支第一对角支分叉以远90 min后松开,建成AMI模型.心肌梗死后1周进行细胞移植,将干细胞悬液(移植组:1×106/ml × 10 ml)或无血清培养液(DMEM)(对照组10 ml)经微导管注入前降支.AMI术后1周(基线)和MSCs移植后6周(终点)各行1次MR扫描,评价移植前后心脏形态、功能、心肌灌注及延迟增强.第2次MR扫描后立即处死动物,分别行冰冻切片、石蜡切片和电镜观察.结果 与对照组比较,移植组在移植6周后左心室整体功能较前明显改善,实验组与对照组比较,左心室平均射血分数(EF)值从(42.7±7.5)%升至(50.1±10.1)%(P＜0.01),左心室节段运动异常数平均减少4个(P＜0.01)、梗死面积减少3.2 cm2(P＜0.01),心脏重量指数增加4.1 g/m2(P＜0.05).病理证实移植组梗死区和梗死周边的病变情况显著轻于对照组,有大量存活心肌,纤维化程度显著减轻;并且可见核大、边集,胞质丰富的幼稚细胞;在梗死区和梗死周边区组织的冰冻切片上可见4-6-二脒基二苯基吲哚(DAPI)阳性的移植细胞存活.免疫荧光检测进一步表明大部分DAPI阳性细胞表达心肌特异性肌钙蛋白T(troponin T),并且表达间隙连接蛋白43(connexin 43).部分DAPI阳性细胞表达平滑肌肌动蛋白(smooth muscle actin)和血管性血友病因子(Von Willebrand),移植组梗死周边区毛细血管密度显著高于对照组[分别为(8.7±2.0)、(4.9±1.3)个/高倍镜](P＜0.01).结论 MRI可作为猪BM-MSCs在体移植前后评价其治疗效果的可靠影像检查方法 .     

磁共振心肌灌注成像及延迟成像检测冠心病心肌缺血的临床研究

目的 探讨MR心肌灌注成像(PI)联合延迟扫描成像检测梗死心肌的价值.资料与方法 对18例经冠状动脉造影证实有冠状动脉狭窄的患者行MR首过心肌灌注及延迟扫描成像检查.分别计算低灌注节段组和正常灌注节段组灌注信号强度参数前后信号增强最大强度(SIp)、相对峰值强化率(SI%)、累积信号强度(ASI)、对比剂到达时间(t0)、强化峰值时间(t1),对比剂流入到强化峰值50%s时间(t1/2)、对比剂流入到强化峰值时间(Tp)、最大曲线上升斜率Slope(α).观察心肌低灌注节段,并与DSA结果比较.测定延迟扫描强化区与无强化区的信号强度值,计算强化区体积占心肌总体积的比值,分析强化区体积所占心肌总体积的比值与每搏输出量之间的相关性.结果 (1)心肌首过灌注成像与冠状动脉造影两种方法存在较好的相关性(X2=21.0,P＜0.05,r=0.53).(2)正常灌注节段组各参数分别为:SIp(162.8±30.2),SI%(136.2±6.6),ASI(931.4±98.1),t0(16.2±1.1),t1/2(18.5±1.4),t1(22.4±1.4),Tp(9.7±1.7),Slope(α)(16.1±1.7).低灌注节段与正常灌注节段参数SIp、SI%、ASI、t1、Tp、Slope(α)差异有统计学意义(P＜0.05),t0、t1/2差异无统计学意义(P＞0.05).SIp、SI%、Tp、Slope(α)为反映心肌首过灌注TIC的特异性参数,能敏感地反映缺血的程度.(3)延迟强化后,异常延迟强化区信号值(616.6±38.4)与正常延迟强化区信号值(304.0±69.0)差异有统计学意义(P＜0.05).异常延迟强化区体积比与患者每搏输出量呈负相关(r=-0.977,P＜0.05).结论 MR心肌PI通过灌注参数的分析可以评估梗死心肌的程度,参照延迟增强的结果,可确定梗死心肌,并计算梗死面积,是对心肌血供情况的最直接反映.     

超顺磁性氧化铁标记鼠骨髓间充质干细胞的体外MR成像研究

目的: 探讨不同浓度超顺磁性氧化铁(SPIO)颗粒标记鼠骨髓间充质干细胞(MSCs)的标记率和对细胞活力的影响,以及MR成像显示磁标记干细胞的可行性.材料和方法: 将不同浓度的SPIO-PLL复合物与培养基混合,行普鲁士蓝染色观察细胞内铁和检测细胞活力.应用1.5T MR仪,以T1WI和T2WI行磁标记干细胞成像.结果: SPIO可有效标记MSCs,标记后的铁颗粒位于细胞质内.SPIO标记的MSCs可引起T2WI信号降低,50、100、150较25μg Fe /ml的信号强度降低明显.结论: SPIO可以简便标记MSCs,并在适当浓度下对细胞活力没有影响,此技术为干细胞移植的MR活体内示踪奠定基础.     

超顺磁性氧化铁标记猪骨髓间充质干细胞的体外MR成像研究

目的 明确超顺磁性氧化铁(SPIO)粒子体外标记猪骨髓间充质干细胞(MSCs)的方法、经MR成像的特征及可成像的最低标记细胞量.方法 分离、纯化、培养猪MSCs,体外进行不同种类SPIO标记,对标记细胞行普鲁士蓝染色及荧光显微镜观察;测量并绘制未标记细胞和标记细胞的MTT生长曲线;选取不同的细胞量组进行标记后MR成像,测量不同扫描序列标记细胞管的信号强度改变,并进行统计学分析.结果 该方法标记MSCs的有效率为100%,普鲁士蓝染色见细胞浆内有多少不等的蓝染铁颗粒;SPIO标记的MSCs在T2WI尤其是FFE(T2*WI)序列信号明显降低;在25 μg Fe/ml培养液标记浓度下,MR成像的最低细胞量为1×105;在不同种类SPIO标记下,2#、3#USPIO与Feridex在T2WI及T2*WI上有统计学差异,而1#USPIO与Feridex在T2WI及T2*WI上无明显统计学差异;Feridex标记MSCs在T2WI及T2*WI上与T1WI之间均有统计学意义. 结论该方法可以简便标记MSCs并且在适当浓度下对MSCs的生物学活性没有影响,MR T2WI和T2*WI序列可敏感显像磁性标记的干细胞.     

铁羧葡胺标记猪间充质干细胞的体内外磁共振成像研究

目的 探讨铁羧葡胺-多聚赖氨酸复合物标记猪骨髓间充质干细胞(MSC)的体外和活体心脏内MR成像的特点.方法 分离培养猪MSC,用含铁羧葡胺-多聚赖氨酸复合物标记细胞24 h.分别于标记后0、4、8、12、16、20 d行普鲁士蓝染色观察细胞内铁,原子吸收分光光度仪测定细胞内含铁量,锥虫蓝排除试验检测细胞活力.对不同时间点、不同细胞数的磁标记干细胞进行1.5 T MR仪体外成像,并对植入猪心肌内的标记细胞进行体内MR成像.结果 ①MSC标记后见胞质中大量普鲁士蓝着色颗粒,标记率达100%,铁离子含量平均为(13.13±2.30)pg/细胞;随细胞的分裂增殖,细胞内铁离子含量逐渐减少,16 d时铁离子含量下降到(0.68±0.20)pg/细胞,接近标记前水平[(0.21±0.06)pg/细胞,P＞0.05].干细胞磁标记后各时间点的锥虫蓝拒染率与未标记细胞无统计学差异(P＞0.05).②3种成像序列中GRE T2*WI信号改变最为明显,成像细胞数量越多,信号强度变化越明显.1×106个细胞进行MR成像,发现随着标记后体外培养时间延长,T2*WI磁标低信号逐渐消失,12 d以后信号强度和标记前无差异(P＞0.05).体外MR成像最少能检测到5×104～1×105个标记的猪MSC.③标记细胞心肌内移植后1周MR成像显示低信号区.结论 应用铁羧葡胺-多聚赖氨酸复合物标记猪MSC安全、高效;体外MR信号强度能一定程度上反映磁标记细胞的数量及增殖情况;1.5 T临床MR成像仪可对植入心脏的磁标记细胞进行活体显像示踪.     

大鼠骨髓间充质干细胞的钆-荧光双标记及MRI体外示踪的研究

目的 应用多聚胺载体,对大鼠骨髓间充质干细胞(MSCs)进行钆喷替酸葡甲胺(Gd-DTPA)及荧光双标记,探讨MSCs MR磁性标记及体外示踪的可行性.方法 以聚乙烯亚胺-罗丹明复合物(JetPEI-FluoR)为载体,制备Gd-DTPA双标记示踪剂,培养分离SD大鼠骨髓MSCs,以此示踪剂体外标记间MSCs.对标记后细胞行生物学性状检测及电镜、荧光镜观察.应用1.5 T MR仪,对标记的干细胞进行sE T1 WI及T2 WI及混合(mixed)回波序列的T1测量,标记细胞正常传代后进行MR检查,观察标记的持久性.标记细胞、未标记细胞的T1 WI信号强度、T1之间的比较使用t检验,台盼蓝拒染率采用两因素重复资料方差分析,不同浓度示踪下细胞吸光度比较采用单因素方差分析.结果双标记示踪剂标记5×105个MSCs,标记成功了4.25×105个,荧光镜下标记率为85%,电镜下钆(Gd)颗粒主要位于胞质内高尔基体周围.双标记示踪剂孵育3、6、12、24 h内标记细胞的台盼蓝拒染率分别为(96.55±2.90)%、(94.17±2.56)%、(97.16±3.12)%、(94.23±2.67)%,相应的未标记细胞的拒染率分别为(95.86±2.67)%、(92.04±2.21)%、(93.38±3.64)%、(92.12±2.53)%,24 h内标记细胞与未标记细胞拒染率差异无统学意义(F=4.523,P＞0.05).细胞增殖实验中,在2.5、5.0、10.0、20.0、30.0、40.0 μl不同浓度示踪剂时,标记细胞的吸光度分别为(0.1884±0.0151)、(0.1878±0.0190)、(0.1741±0.0160)、(0.1135±0.0215)、(0.1079±0.0145)、(0.0811±0.0079),未标记细胞为(0.1940±0.0116),Gd-DTPA 30.0 μl以下标记细胞与未标记细胞吸光度差异无统计学意义(q'=0.2225～0.9458,P＞0.05).标记后细胞凋亡指数为5.08%,对照组未标记细胞为3.86%.未标记细胞T1 WI平均信号强度及T1分别为240.3±24.7、(2457±56)ms,而标记细胞为336.2±20.7、(1102±64)ms,两者间差异有统计学意义(t值分别为12.656、17.889,P值均＜0.01),T1 WI可监测到最低密度为5×103个标记细胞.标记细胞正常传代后,MRI体外可持续显示至第4代标记细胞.结论应用多聚胺载体对大鼠间充质干细胞进行Gd-DTPA及荧光双标记,安全有效,MRI能示踪体外双标记的干细胞.     

USPIO标记脐带间充质干细胞靶向小鼠肺癌MR、病理对照研究

目的 将USPIO-PLL标记人脐带间充质干细胞(MSCs)移植入肺癌LLC种植瘤的小鼠,利用3.0T MR对MSCs活体示踪;运用免疫组化SABC法,探讨MSCs与血管内皮细胞生长因子(VEGF)表达及肿瘤血管的关系;综合分析移植MSCs对肺癌的影响.方法 培养人脐带MSCs;以多聚赖氨酸(PLL)为转染剂,用USPIO对MSCs-PLL进行磁性标记;将磁标记的MSCs通过鼠尾静脉植入LLC种植瘤小鼠体内,分别于移植前、移植后1 d、10 d行MRI观察;组织块行免疫组化.结果 (1)移植后1 d MRI可监测到MSCs到达肿瘤区,10 d到达肿瘤区MSCs增多,MRI信号降低,差异有统计学意义(P<0.05);移植1 d、10 d抑瘤率均为正值;(2)移植后10 d,MSCs移植组VEGF表达阳性率为86.67％,MVD值为44.22±12.36;NS组VEGF表达阳性率为26.67％,MVD值为20.29±8.47;VEGF阳性表达及微血管密度(MVD)值组差别均有统计学意义(P<0.05).结论 3.0T MR可以有效进行干细胞移植后的活体示踪;干细胞对肺癌具有双向作用:既可定向趋化分化抑制肿瘤生长,也可一定程度增强VEGF表达及微血管形成.     

经脾移植SPIO-PLL标记的诱导后大鼠胰岛素分泌细胞及MR示踪研究

目的 超顺磁性氧化铁颗粒及多聚左旋赖氨酸复合体(SPIO-PLL)标记诱导后的大鼠胰岛素分泌细胞,移植入正常大鼠脾,应用1.5 T MR仪进行活体成像,为胰岛素分泌细咆移植后的活体示踪提供依据.材料与方法将大鼠骨髓间质干细胞(BMSCs)体外诱导成胰岛素分泌细胞,SPIO-PLL标记细胞.10只受体大鼠分二组,每组5只.将标记后的胰岛素分泌细胞(标记组)和未标记的胰岛素分泌细胞(未标记组)分别移植入脾.各组分别于移植前、移植后5天、10天、14天及21天对脾进行T1WI、T2WI、T2*WI三个序列MR扫描,观察脾信号改变情况,在T2*WI序列测量移植部位脾信噪比(SNR),与各时间点脾组织切片普鲁士蓝染色对照.结果 与移植前相比,标记组脾移植部位SNR值明显降低,差异有统计学意义(F=182.92,P<0.05),但移植后各时间点SNR值差异无统计学意义(Bonferroni法,P>0.05).未标记组脾移植前后SNR值差异无统计学意义(F=0.98,P>0.05).脾组织切片普鲁士蓝染色显示标记组染色阳性部位沿注射针道分布,与MRI信号降低区域基本一致.结论 SPIO-PLL可以有效标记诱导后大鼠胰岛素分泌细胞.临床应用型1.5 T MR仪可对经脾移植的标记细胞进行活体示踪.     

心肌梗死模型大鼠梗死区周围心肌C3G蛋白的表达变化及其意义

目的观察心肌梗死模型大鼠梗死区周围心肌C3G蛋白表达的改变及其意义。方法健康雄性SD大鼠随机分为心肌梗死组和假手术组,按照Litwin方法建立实验性大鼠心肌梗死及假手术模型。于术后24h和12周处死两组大鼠,收集心肌标本。取心尖部心肌(心肌梗死组取含梗死区的心肌组织),采用苦味酸天狼星及免疫组化方法检测心肌Ⅰ、Ⅲ型胶原容积(CVFⅠ、Ⅲ)及C3G蛋白表达情况;取心底部心肌(心肌梗死组取非梗死区的心肌组织),采用Western blotting检测C3G蛋白的相对表达量。结果苦味酸天狼星染色结果显示,心肌梗死后12周组心肌细胞中CVFⅠ、Ⅲ分别为14.01±2.73、4.80±0.64,明显高于假手术后24h组(3.15±0.70、1.42±0.48),心肌梗死后24h组(3.68±0.95、1.53±0.61)以及假手术后12周组(3.27±0.65、1.47±0.52),差异有统计学意义(P<0.05),而后3组间差异无统计学意义(P>0.05)。免疫组化检测显示,心肌梗死后12周组心肌中C3G蛋白表达较其他3组均显著增加(P<0.05),而后3组间比较无明显差异(P>0.05)。Western blotting检测显示,与假手术后12周组(0.22±0.04)、假手术后24h组(0.22±0.04)、心肌梗死后24h组(0.29±0.02)比较,心肌梗死后12周组梗死区周围心肌C3G蛋白表达(0.56±0.06)显著增加(P<0.05)。结论心肌中存在C3G蛋白表达。发生心肌梗死后,梗死区周围心肌C3G蛋白表达水平显著增加,提示C3G蛋白参与了梗死后的心肌重塑。     

Cardiac tumors: assessment with Gd-DTPA enhanced MR imaging

Previous studies have shown the value of MR imaging for the identification of cardiac masses. The distinction of intramural tumors from normal myocardium may be equivocal because of the similarity of signal intensity between tumor and normal myocardium on ECG-gated SE images. The purpose of this study was to assess the role of Gd-DTPA for improving the contrast between cardiac tumors and myocardium. Four patients with established or suspected cardiac tumors were imaged with a 1.5 T imager. The T1-weighted images (TR = RR interval, TE = 20-30 ms) were obtained before and immediately after the intravenous injection of Gd-DTPA, at a dosage of 0.1 mmol/kg. Tumors were identified in three patients. All tumors were isointense to the myocardium in precontrast images but demonstrated differential enhancement relative to myocardium after the administration of Gd-DTPA. Two tumors were hyperintense relative to myocardium, and the third was mostly hypointense, surrounded by a hyperintense rim. In the remaining case, no tumor was found and the myocardium was homogeneously enhanced on postgadolinium images. Gadolinium DTPA can produce differential enhancement of tumor from normal myocardium and therefore demonstrate intramural masses.     

125I标记CD90单克隆抗体靶向结合间充质干细胞的实验研究

目的:制备 125I标记的CD90单克隆抗体（mAb）,探讨其示踪间充质干细胞（MSCs）的可能性。 方法:采用氯胺T法对CD90 mAb进行 125I标记,测定标记率。（1）体外实验：检测MSCs和 125I-CD90 mAb孵育后上清液和沉淀的放射性计数,分别计算6个不...     

MRI of focal nodular hyperplasia (FNH) with gadobenate dimeglumine (Gd-BOPTA) and SPIO (ferumoxides): an intra-individual comparison

PURPOSE: To compare the efficacy of two different MR contrast agents for the detection and diagnosis of focal nodular hyperplasia (FNH). MATERIALS AND METHODS: Fifty patients with 83 FNH lesions detected on spiral CT were studied in two different MRI sessions with Gd-BOPTA (MultiHance) and ferumoxides (Endorem). MRI with Gd-BOPTA was performed precontrast (T1wGRE and T2wTSE sequences) and during the dynamic and late (1-3 hours) phases after injection (T1wGRE sequences only). MRI with ferumoxides (T1wGRE and T2wTSE sequences) was performed before and at least 30 minutes after injection. Hyper- or isointensity of FNH in the late phase was considered typical for Gd-BOPTA, while isointensity or lesion hypointensity was considered typical for ferumoxides. RESULTS: With Gd-BOPTA, 83 FNH lesions (100%) appeared hyperintense during the arterial phase of dynamic MRI. All but one lesion was iso- or slightly hyperintense in the portal-venous and equilibrium phases. In the late phase, 81 FNH lesions were hyper- or isointense to the surrounding parenchyma, with two lesions appearing slightly hypointense. With ferumoxides, a significant (P < 0.001) number (21/83, 25.3%) of FNH lesions (mean diameter = 16.8 +/- 6.6 mm) were not visible. Of the visible FNH lesions, 38/62 were slightly hyperintense, and 24/62 were isointense to the surrounding parenchyma on the T2wTSE images. On the T1wGRE images, 42/62 lesions were isointense, 19/62 were slightly hyperintense, and one lesion was slightly hypointense. Seventeen lesions in 12 patients with previous neoplasia were all detected after Gd-BOPTA administration, whereas only nine of these 17 lesions (52.9%) were detected after ferumoxide administration. Two of these nine lesions showed atypical enhancement features. CONCLUSION: Gd-BOPTA-enhanced MRI is significantly better than ferumoxide-enhanced MRI for the identification and characterization of FNH.     

MRI对急性心肌梗死后不同心脏状态下干细胞移植后体内再分布与疗效评价的动物实验研究

目的 探讨MRI在研究停跳与不停跳两种心脏状态下,经猪心肌梗死模型心肌注射骨髓间充质干细胞后全身各主要脏器(心、肝、脾、肾)干细胞的早期再分布及疗效评价中的应用价值.方法 干细胞提取自雄性猪并用超顺磁性氧化铁标记.雌性猪制成急性心肌梗死模型7 d后数字表随机方法分为4组.第1组为心脏停跳细胞注射组(6只),体外循环后心脏停跳,超顺磁性氧化铁标记的干细胞(1×108)经心肌注入心肌梗死周边区.第2组为不停跳心脏细胞注射组(6只),相同的细胞在心脏跳动下经心肌注入心肌梗死周边区.第3组停跳心脏对照组(6只)和第4组不停跳心脏对照组(6只)中,相同剂量的生理盐水分别在停跳和不停跳状态下经心肌注入心肌梗死周边区.3 d后,行MR T2*WI示踪和心功能检查.并取动物心、肝、脾、肺、肾的标本,用实时定量聚合酶链反应(qRT-PCR)检测雄性细胞特异性的性别决定区域(SRY)基因定量检查.统计学分析采用方差分析和t检验.结果 第1～4组术前左心室舒张末期容积(LVEDV)分别为(56.8±5.3)、(54.8±6.8)、(57.4±4.3)和(56.8±2.8) ml,术后LVEDV分别为(65.2±5.2)、(63.2±3.7)、(60.2±4.7)和(62.2±4.4) ml,术前左心室收缩末期容积(LVESV)分别为(33.5±7.6)、(32.3±5.3)、(33.5±3.6)和(32.7±4.6) ml,术后LVESV分别为(37.3±5.6)、(36.3±6.9)、(34.3±5.4)和(36.3±8.1) ml;术前左心室射血分数值(LVEF)分别为(42.3±7.2)%、(41.7±6.8)%、(41.8±8.6)%和(42.7±7.7)%,术后LVEF分别为(44.5±8.7)%、(43.1±7.4)%、(42.8±5.6)%和(43.3±8.4)%;术前心肌梗死面积(MI)分别为(6.5±2.1)、(6.4±1.9)、(6.5±2.5)和(6.4±2.6) cm2,术后MI分别为(6.4±2.3)、(6.2±2.6)、(6.3±2.5)和(6.4±2.8) cm2,差异均无统计学意义(术前P值均＞0.05,F值分别为0.277、0.066、0.066、0.003;术后P值均＞0.05,F值分别为1.137、0.182、0.021及0.008).心脏中第1组较第2组T2*降低显著[(-22.3±2.2)和(-17.0±0.8) ms,t=-5.489,P＜0.01],而脾脏中第2组较第1组T2*值降低显著[(-7.7±0.7)和(-13.3±1.1) ms,t=9.055,P＜0.01],在肝脏及肾脏2组差异无统计学意义(肝脏t=-0.532,P>0.05,肾脏t=-0.113,P>0.05).SRY基因和qRT-PCR结果,第1组及第2组心脏[(150±62)和(72±4) U/L]、脾脏[(131±1)和(233±17) U/L]及肝脏[(17±1)和(9±5) U/L]差异有统计学意义(P值均＜0.05,t值分别为3.109、-13.286及3.492),病理学检查可以见移植细胞呈普鲁士蓝染色阳性,与MRI有很好的一致性.结论 干细胞氧化铁颗粒标记后,MRI可以作为方便而有效的手段在移植早期活体示踪干细胞,评价其在体内的分布情况.在心脏停跳状态下经心肌注射骨髓间充质干细胞将更有利于细胞在心脏的滞留.

Abstract：

Objective To evaluate the efficacy of MRI for assessment of re-distribution of bone marrow mesenchymal stem cells injected intramyocardially in main organs (heart, liver, spleen and kidney) under different heart status (beating or arresting) in a porcine model. Methods Bone marrow-derived mesenchymal stem cells were obtained from the male swine and labeled with iron oxide during culture. Acute myocardial infarction was created in female swine, one week later, the survivors were randomly divided into 4 groups. Cardiopulmonary bypass was set up to arrest the heart, and then labeled cells (1×108) were intramyocardially injected into the border of the infracted myocardium in group 1 (n=6). The same volume of cells was grafted into the beating heart in group 2 (n=6). In group 3 and 4, saline was injected into either the arresting or beating myocardium. Three days later, re-distribution of stem cells and cardiac function were assessed by T2*WI and cine MRI, respectively. All animals were sacrificed for histology and real-time quantitative polymerase chain reaction (RT-PCR) of sex-determining region on Y-chromosome (SRY) investigation.The ANOVA and t test was used for statistics. Results The left ventricular end-diastolic volume (LVEDV) before transplantation for group 1-4 were: (56.8±5.3),(54.8±6.8),(57.4±4.3)and(56.8±2.8) ml, and after transplantation for group 1-4 were: (65.2±5.2),(63.2±3.7),(60.2±4.7)and(62.2±4.4) ml. The left ventricular end-systolic volume (LVESV) before transplantation for group 1-4 were: (33.5±7.6),(32.3±5.3),(33.5±3.6)and(32.7±4.6) ml,and after transplantation for group 1-4 were: (37.3±5.6),(36.3±6.9),(34.3±5.4)and(36.3±8.1) ml. The left ventricular EF values (LVEF) before transplantation for group 1-4 were: (42.3±7.2)%,(41.7±6.8)%,(41.8±8.6)% and(42.7±7.7)%,and after transplantation for group 1-4 were: (44.5±8.7)%,(43.1±7.4)%,(42.8±5.6)% and(43.3±8.4)%. The myocardial infarction area (MI) before transplantation for group 1-4 were: (6.5±2.1),(6.4±1.9),(6.5±2.5)and(6.4±2.6) cm2,and after transplantation for group 1-4 were: (6.4±2.3),(6.2±2.6),(6.3±2.5)and(6.4±2.8) cm2 . There were no statistical differences before and after transplantation in these 4 groups[P values of before and after transplantation for LVEDV, LVESV, LVEF,MI were >0.05 (F= 0.277, 0.066,0.066, 0.003); and >0.05 (F= 1.137,0.182,0.021,0.008),respectively]. The T2 value of the infracted myocardium in group 1 decreased more obviously than that in group 2[(-22.3 ± 2.2) vs (-17.0 ± 0.8) ms, t=-5.489, P＜0.01], while the T2 value of the spleen decreased more significantly in group 2 than that in group 1[(-7.7 ± 0.7) vs (-13.3 ± 1.1) ms,t=9.055, P＜0.01]. The T2 values of the liver and kidney were no significant differences in group 1 and 2 (liver, t=-0.532,P>0.05 and kidney, t=-0.113,P>0.05). The results of RT-PCR in group 1 and 2 showed significant differences in heart[(150±62) vs (72±4) U/L ,P<0.05, t=3.109], spleen[(131±1) vs (233±17) U/L, P＜0.01, t=- 13.286]and liver[(17±1) vs (9±5) U/L ,P<0.01,t= 3.492]. Pathological examination demonstrated that the transplanted stem cells were positive for Prussian blue staining, which had a good correlation with MRI results. Conclusion MRI can serve as a convenient and efficient imaging method to track the migration of stem cells with SPIO labeled in early stage and evaluate its early re-distribution in vivo. Injection of bone marrow mesenchymal stem cells in the arresting heart could favor retaining more cells in the myocardium.     

高CO2分压下大鼠神经胶质瘤肿瘤血管的MR灌注成像特点

目的 了解MR灌注成像显示肿瘤血管成熟度和变异度的可行性.方法 20只雄性SD大鼠,采用数字表法随机平分为肿瘤组和正常对照组.肿瘤组大鼠于右侧尾状核区种植C6胶质瘤细胞,复制大鼠脑胶质瘤模型.种植肿瘤细胞后4周,两组大鼠吸入高浓度CO2混合气体,吸入气体前后,分别行全脑灌注成像扫描,检测局部相对脑血容量(rCBV)、局部相对脑血流量(rCBF).扫描前测定大鼠血CO2分压、pH值等血气指标.检查后处死肿瘤组大鼠并取脑固定,全脑切片,分别行苏木精-伊红及鼠特异性平滑肌抗体反应素(SMA)抗体免疫组织化学染色.光学显微镜下观察肿瘤组织特征并进行SMA阳性血管计数.采用配对t检验比较两组大鼠脑组织MR灌注值、肿瘤组织微血管计数及血气指标的差异,并将免疫组织化学检查结果与MR检查结果进行Pearson相关性分析.结果胶质瘤的rCBV和rCBF呈明显的高灌注.所有大鼠在吸入含高浓度CO2的混合气体15 min后,血液CO2分压肿瘤组从(4.69±0.62)kPa升高至(7.62±0.81)kPa,对照组从(4.67±0.51)kPa升高至(7.63±0.78)kPa,差异具有统计学意义(t值分别为6.09,7.012,P值均＜0.05);pH值肿瘤组从(7.42±0.03)降至(7.10±0.05),对照组从(7.40±0.04)降至(7.08±0.02),差异具有统计学意义(t值分别为2.745,2.693,P值均＜0.05).肿瘤实质部分的rCBV和rCBF的增加率分别为(26±17)%和(26±18)%,低于肿瘤组健侧正常脑组织[分别为(90±32)%和(45±14)%],二者差异具有统计学意义(t值分别为5.05,2.355,P值均＜0.05).SMA染色部位在血管的平滑肌细胞,形态规则,肿瘤内SMA阳性血管较正常脑组织的阳性血管管壁薄,管腔直径宽;肿瘤内SMA阳性血管[(6.7±2.8)个/高倍视野]明显少于肿瘤组健侧脑组织[(12.7±2.8)个/高倍视野](t=1.86,P＜0.05).吸入高浓度CO2混合气体后,肿瘤实质区的rCBV和rCBF的变化率与免疫组织化学的SMA阳性血管计数之间均无显著的相关性(r值分别为0.504和0.607,P值均＞0.05).但正常脑组织的rCBV和rCBF变化率与其SMA阳性血管计数之间呈正相关(r值分别为0.721和0.525,P值均＜0.05).结论 MR灌注技术在改变血液CO2分压的条件下可以反映正常脑组织和肿瘤组织血流变化,进而间接判断肿瘤血管的成熟度.     

In vivo tracking of genetically engineered, anti-HER2/neu directed natural killer cells to HER2/neu positive mammary tumors with magnetic resonance imaging

The purpose of this study is to optimize labeling of the human natural killer (NK) cell line NK-92 with iron-oxide-based contrast agents and to monitor the in vivo distribution of genetically engineered NK-92 cells, which are directed against HER2/neu receptors, to HER2/neu positive mammary tumors with magnetic resonance (MR) imaging. Parental NK-92 cells and genetically modified HER2/neu specific NK-92-scFv(FRP5)-zeta cells, expressing a chimeric antigen receptor specific to the tumor-associated ErbB2 (HER2/neu) antigen, were labeled with ferumoxides and ferucarbotran using simple incubation, lipofection and electroporation techniques. Labeling efficiency was evaluated by MR imaging, Prussian blue stains and spectrometry. Subsequently, ferucarbotran-labeled NK-92-scFv(FRP5)-zeta (n=3) or parental NK-92 cells were intravenously injected into the tail vein of six mice with HER2/neu-positive NIH 3T3 mammary tumors, implanted in the mammary fat pad. The accumulation of the cells in the tumors was monitored by MR imaging before and 12 and 24 h after cell injection (p.i.). MR data were correlated with histopathology. Both the parental NK-92 and the genetically modified NK-92-scFv(FRP5)-zeta cells could be labeled with ferucarbotran and ferumoxides by lipofection and electroporation, but not by simple incubation. The intracellular cytoplasmatic iron-oxide uptake was significantly higher after labeling with ferucarbotran than ferumoxides (P<0.05). After intravenous injection of 5×10⁶ NK-92-scFv(FRP5)-zeta cells into tumor-bearing mice, MR showed a progressive signal decline in HER2/neu-positive mammary tumors at 12 and 24 h (p.i.). Conversely, injection of 5×10⁶ parental NK-92 control cells, not directed against HER2/neu receptors, did not cause significant signal intensity changes of the tumors. Histopathology confirmed an accumulation of the former, but not the latter cells in tumor tissue. The human natural killer cell line NK-92 can be efficiently labeled with clinically applicable iron-oxide contrast agents, and the accumulation of these labeled cells in murine tumors can be monitored in vivo with MR imaging. This MR cell tracking technique may be applied to monitor NK-cell based immunotherapies in patients in order to assess the presence and extent of NK-cell tumor accumulations and, thus, to determine therapy response early and non-invasively.     

Paramagnetic pyrophosphate. Preliminary studies on magnetic resonance contrast enhancement of acute myocardial infarction

Ferric pyrophosphate (Fe-PyP) was investigated in an animal model of acute myocardial infarction for its potential to provide contrast enhancement of the peri-infarct zone using magnetic resonance (MR) imaging. Radiotracer studies compared the biodistribution of soluble 59Fe-PyP with 99mTc-PyP in excised tissue samples. Preferential localization of 59Fe-PyP in the peri-infarct zone was found to be similar to 99mTc-PyP. The ratio (percent dose/gram of tissue) at the edge of the infarct to normal tissue was 1.30 +/- 0.16 and 1.44 +/- 0.33 for 99mTc-PyP and 59Fe-PyP, respectively. In initial studies with high doses of the contrast agent, gated T1-weighted MR images of animals with 48-hour-old infarcts were obtained at 15-minute intervals after injection of Fe-PyP at a dose of 350 mg/kg. Contrast enhancement of the infarct zone was observed in all studies and was maximal 15-30 minutes after injection. Signal intensity ratios (infarct/normal) increased from a baseline 1.31 +/- 0.22 to a peak 1.90 +/- 0.57. Studies were then performed with smaller amounts of Fe-PyP. Images obtained with 50 mg/kg Fe-PyP showed contrast enhancement beginning at 60 minutes. Toxicology studies showed primarily respiratory effects, which became significant at doses of 190 mg/kg. These preliminary studies suggest that Fe-PyP potentially could serve as an MR contrast agent to localize and size acute myocardial infarcts; however, its clinical use may be limited by potential toxicity and dose limitations.