Meier Elizabeth M, Wu Bin, Siddiqui Aamir, Tepper Donna G, Longaker Michael T, Lam Mai T
Department of Biomedical Engineering, Wayne State University, Detroit, Mich.; Department of Plastic Surgery, Henry Ford Health System, Detroit, Mich.; and Hagey Laboratory for Pediatric Regenerative Medicine, Department of Surgery, Plastic and Reconstructive Surgery, Stanford University School of Medicine, Stanford, Calif.
Plast Reconstr Surg Glob Open. 2016 Sep 16;4(9):e864. doi: 10.1097/GOX.0000000000000854. eCollection 2016 Sep.
Efforts have been made to engineer knee meniscus tissue for injury repair, yet most attempts have been unsuccessful. Creating a cell source that resembles the complex, heterogeneous phenotype of the meniscus cell remains difficult. Stem cell differentiation has been investigated, mainly using bone marrow mesenchymal cells and biochemical means for differentiation, resulting in no solution. Mechanical stimulation has been investigated to an extent with no conclusion. Here, we explore the potential for and effectiveness of mechanical stimulation to induce the meniscal phenotype in adipose-derived stromal cells.
Human adipose-derived stromal cells were chosen for their fibrogenic nature and conduciveness for chondrogenesis. Biochemical and mechanical stimulation were investigated. Biochemical stimulation included fibrogenic and chondrogenic media. For mechanical stimulation, a custom-built device was used to apply constant, cyclical, uniaxial strain for up to 6 hours. Strain and frequency varied.
Under biochemical stimulation, both fibrogenic (collagen I, versican) and chondrogenic (collagen II, Sox9, aggrecan) genes were expressed by cells exposed to either fibrogenic or chondrogenic biochemical factors. Mechanical strain was found to preferentially promote fibrogenesis over chondrogenesis, confirming that tensile strain is an effective fibrogenic cue. Three hours at 10% strain and 1 Hz in chondrogenic media resulted in the highest expression of fibrochondrogenic genes. Although mechanical stimulation did not seem to affect protein level expression, biochemical means did affect protein level presence of collagen fibers.
Mechanical stimulation can be a useful differentiation tool for mechanoresponsive cell types as long as biochemical factors are also integrated.
人们已努力构建用于损伤修复的膝半月板组织，但大多数尝试都未成功。创建一种类似于半月板细胞复杂、异质性表型的细胞来源仍然很困难。已对干细胞分化进行了研究，主要使用骨髓间充质细胞和生化分化方法，但未找到解决方案。对机械刺激也进行了一定程度的研究，但尚无定论。在此，我们探讨机械刺激在诱导脂肪来源的基质细胞形成半月板表型方面的潜力和有效性。
选择人脂肪来源的基质细胞，因其具有成纤维特性且有利于软骨形成。研究了生化和机械刺激。生化刺激包括成纤维和软骨形成培养基。对于机械刺激，使用定制设备施加恒定、周期性、单轴应变长达6小时。应变和频率有所变化。
在生化刺激下，暴露于成纤维或软骨形成生化因子的细胞均表达了成纤维（I型胶原蛋白、多功能蛋白聚糖）和软骨形成（II型胶原蛋白、Sox9、聚集蛋白聚糖）基因。发现机械应变优先促进成纤维作用而非软骨形成，证实拉伸应变是一种有效的成纤维信号。在软骨形成培养基中以10%应变和1Hz施加3小时导致纤维软骨形成基因的表达最高。虽然机械刺激似乎不影响蛋白质水平表达，但生化方法确实影响胶原蛋白纤维的蛋白质水平存在。
只要结合生化因素，机械刺激对于机械反应性细胞类型可能是一种有用的分化工具。
