摘要
表示为基于 radiopharmaceutical 的成像为生物体之发光成像或 HSV1 thymidine kinase (HSV1-TK ) 编码任何一个萤火虫酶(fLuc ) 的记者 transgene 的 lentiviral 向量的二种新类型被构造监视人的胚胎的干细胞(hESC ) 在在移植以后的活老鼠的嫁接和增长。任何一个 transgene 的组成的表示没在文化改变 hESCs 的性质。我们下次在 SCID 鼠标监视了 teratomas 的形成到测试(1 ) 是否修改基因的 hESCs 维持他们的发展 pluripotency，并且(2 ) 是否支撑了记者基因表示，允许 noninvasive，在一个活鼠标模型的 hESC 衍生物的整个身体的成像。我们在接种以后从修改基因的房间以及野类型的 hESCs 2-4 月的两种类型观察了 teratoma 形成。用一个光成像系统，从 fLuc-transduced hESCs 的生物体之发光容易在在摸得出的肿瘤能被检测以前，长忍受 teratomas 的老鼠被检测。开发一个 noninvasive 成像方法对诊所更容易地可译，我们也利用了 HSV1-TK 和它的特定的底层， 1-(2 鈥 ? deoxy-2 鈥 ?fluoro- 尾 - D-arabinofuranosyl )-5-[125I]iodouracil ([125I ] FIAU ) ，记者 / 探查对。在全身的管理以后，[125I ] FIAU 是仅仅由编码 transgene 的 HSV1-TK 酶的 phosphorylated 并且在 transduced 以内保留(并且移植) 房间，由单个光子的排放允许敏感、量的成像计算了断层摄影术。象这些那样的 Noninvasive 成像方法可以使我们能在实时接受者以内重复地监视移植人的干细胞的存在和分发在上一通过记者基因的表达式长期。
Two new types of lentiviral vectors expressing a reporter transgene encoding either firefly luciferase （fLuc） for bioluminescence imaging or the HSV1 thymidine kinase （HSV1-TK） for radiopharmaceutical-based imaging were constructed to monitor human embryonic stem cell （hESC） engraftment and proliferation in live mice after trans- plantation. The constitutive expression of either transgene did not alter the properties of hESCs in the culture. We next monitored the formation of teratomas in SCID mice to test （1） whether the gene-modified hESCs maintain their developmental pluripotency, and （2） whether sustained reporter gene expression allows noninvasive, whole-body imaging of hESC derivatives in a live mouse model. We observed teratoma formation from both types of gene-modified cells as well as wild-type hESCs 2-4 months after inoculation. Using an optical imaging system, bioluminescence from the fLuc-transduced hESCs was easily detected in mice bearing teratomas long before palpable tumors could be detected. To develop a noninvasive imaging method more readily translatable to the clinic, we also utilized HSV1-TK and its specific substrate, 1-（2＇-deoxy-2＇-fluoro-β-D-arabinofuranosyl）-5-[^125I]iodouracil（[^125I]FIAU）, as a reporter/ probe pair. After systemic administration, [^125I]FIAU is phosphorylated only by the transgene-encoded HSV1-TK enzyme and retained within transduced （and transplanted） cells, allowing sensitive and quantitative imaging by single-photon emission computed tomography. Noninvasive imaging methods such as these may enable us to monitor the presence and distribution of transplanted human stem cells repetitively within live recipients over a long term through the expression of a reporter gene.
