脐带间充质干细胞片经皮下移植比分散的干细胞注射更能增强细胞的保留和存活。

BACKGROUND: Human umbilical cord-derived mesenchymal stem cell (hUC-MSC) sheets have recently attracted attention as an alternative approach to injected cell suspensions for stem cell therapy. However, cell engraftment and cytokine expression levels between hUC-MSC sheets and their cell suspensions in vivo have not yet been compared. This study compares hUC-MSC in vivo engraftment efficacy and cytokine expression for both hUC-MSC sheets and cell suspensions. METHODS: hUC-MSC sheets were prepared using temperature-responsive cell culture; two types of hUC-MSC suspensions were prepared, either by enzymatic treatment (trypsin) or by enzyme-free temperature reduction using temperature-responsive cell cultureware. hUC-MSC sheets and suspensions were transplanted subcutaneously into ICR mice through subcutaneous surgical placement and intravenous injection, respectively. hUC-MSC sheet engraftment after subcutaneous surgical transplantation was investigated by in vivo imaging while intravenously injected cell suspensions were analyzing using in vitro organ imaging. Cytokine levels in both transplant site tissues and blood were quantified by enzyme-linked immunosorbent assay. RESULTS: After subcutaneous transplant, hUC-MSC sheets exhibited longer engraftment duration than hUC-MSC suspensions. This was attributed to extracellular matrix (ECM) and cell-cell junctions retained in sheets but enzymatically altered in suspensions. hUC-MSC suspensions harvested using enzyme-free temperature reduction exhibited relatively long engraftment duration after intravenous injection compared to suspensions prepared using trypsin, as enzyme-free harvest preserved cellular ECM. High HGF and TGF-β1 levels were observed in sheet-transplanted sites compared to hUC-MSC suspension sites. However, no differences in human cytokine levels in murine blood were detected, indicating that hUC-MSC sheets might exert local paracrine rather than endocrine effects. CONCLUSIONS: hUC-MSC sheet transplantation could be a more effective cell therapeutic approach due to enhanced engraftment and secretion of therapeutic cytokines over injected hUC-MSC suspensions.

背景：人脐带间充质干细胞（hUC-MSC）片最近作为干细胞治疗中注射细胞悬浮液的替代方法受到关注。然而，hUC-MSC 片与其体内细胞悬浮液之间的细胞植入和细胞因子表达水平尚未进行比较。本研究比较了 hUC-MSC 片和细胞悬浮液的体内植入效果和细胞因子表达。

方法：使用温度响应细胞培养制备 hUC-MSC 片；通过酶处理（胰蛋白酶）或使用无酶的温度响应细胞培养试剂盒通过温度降低制备两种类型的 hUC-MSC 悬浮液。通过皮下手术将 hUC-MSC 片和悬浮液分别移植到 ICR 小鼠的皮下，通过静脉注射将 hUC-MSC 悬浮液移植到 ICR 小鼠体内。通过体内成像研究皮下手术移植后的 hUC-MSC 片植入情况，通过体外器官成像分析静脉注射的细胞悬浮液。通过酶联免疫吸附试验定量测定移植部位组织和血液中的细胞因子水平。

结果：皮下移植后，hUC-MSC 片的植入持续时间长于 hUC-MSC 悬浮液。这归因于片材中保留的细胞外基质（ECM）和细胞-细胞连接，但在悬浮液中被酶改变。使用无酶的温度降低法收获的 hUC-MSC 悬浮液在静脉注射后表现出相对较长的植入持续时间，与使用胰蛋白酶制备的悬浮液相比，因为无酶收获保存了细胞 ECM。与 hUC-MSC 悬浮液移植部位相比，在片材移植部位观察到较高的 HGF 和 TGF-β1 水平。然而，在鼠血中未检测到人细胞因子水平的差异，表明 hUC-MSC 片可能发挥局部旁分泌而非内分泌作用。

结论：hUC-MSC 片移植可能是一种更有效的细胞治疗方法，因为与注射的 hUC-MSC 悬浮液相比，它增强了植入和治疗性细胞因子的分泌。