Homma Yasuhiro, Kaneko Kazuo, Hernigou Philippe
Orthopaedic Surgery Department, Juntendo University, Bunkyō, Tokyo, Japan.
Int Orthop. 2014 Oct;38(10):2033-44. doi: 10.1007/s00264-013-2221-x. Epub 2013 Dec 10.
Bone marrow derived mesenchymal stem cells (BM-MSCs) have been proposed to improve allografts used during hip revision. However, no study has reported the number of MSCs that could be associated with the allograft and the best technique to load MSCs in allografts. The optimal loading technique should combine methods to increase the initial cell density and create an appropriate environment to accelerate the efficiency of the cell-allograft constructs into clinically applicable grafts. We designed a study to evaluate the number of MSCs in an autograft femoral head considered as the gold standard and to determine the best operating room procedure for loading in allograft with MSCs to approach the same number as in an autograft femoral head. Therefore this study explored a potential of charging whole femoral head allografts with autologous MSCs from iliac crest aspirate for hip revision procedures.
First, the study evaluated the total number of mesenchymal stem cells (MSCs) in 1 cc of an average autograft femoral head; this number then serves as a target for loading allografts, in order to achieve the same density of MSCs. For the loading technique itself, several questions were asked and hence several options were investigated. For example, is it better to load the whole allograft or break it up into several fragments? Which way of injecting works best for the whole femoral head allograft (through cartilage or femoral neck)? How concentrated (in terms of MSCs) should the injected iliac crest marrow be? Bone marrow for injection in allografts was obtained from residual marrow from patients undergoing surgical procedures with concentrated bone marrow. With this bone marrow (with and without concentration) we tested different techniques (injection and soaking) to load stem cells in allografts of different sizes: bulk allografts, pieces or blocks (8 or 1 cm(3) blocks) and morselized fragments (from 125 to 8 mm(3)) or particules (1 mm(3)). We also evaluated the release of MSCs from fragments of autografts and allografts loaded with MSCs in cultured medium.
The femoral head autografts contained a lower concentration of MSCs than the iliac crests of the same patient. However, in absence of concentration, with bone marrow aspirated from the iliac crest, we were not able to load in the femoral head allograft the same number of MSCs as the number present in an autograft. The loaded volume of bone marrow (and the corresponding number of MSCs) depended on the technique (injecting, soaking) as well as on the volume and shape of the allografts. The seeding efficiency of loading MSCs in allografts increased with the concentration of MSCs in the bone marrow. With concentrated bone marrow, supercharging the allograft with MSCs (as compared with an autograft) was possible in the operating room, and the number of MSCs supercharged in allografts was predictable.
The loaded volume of bone marrow depended on the technique (injecting, soaking) as well as on the volume and shape of the allografts. With concentrated bone marrow, the allograft could be charged with a similar or higher number of MSCs than the number present in a femoral head autograft.
有人提出骨髓间充质干细胞（BM-MSCs）可改善髋关节翻修术中使用的同种异体移植物。然而，尚无研究报道与同种异体移植物相关的间充质干细胞数量以及将间充质干细胞加载到同种异体移植物中的最佳技术。最佳加载技术应结合提高初始细胞密度的方法，并创造适当环境以加速细胞-同种异体移植物构建体转化为临床适用移植物的效率。我们设计了一项研究，以评估被视为金标准的自体股骨头中间充质干细胞的数量，并确定在同种异体移植物中加载间充质干细胞以使其数量接近自体股骨头中间充质干细胞数量的最佳手术室操作程序。因此，本研究探索了用来自髂嵴抽吸物的自体间充质干细胞对全股骨头同种异体移植物进行加载以用于髋关节翻修手术的潜力。
首先，该研究评估了1立方厘米平均自体股骨头中间充质干细胞（MSCs）的总数；该数量随后用作加载同种异体移植物的目标，以实现相同的间充质干细胞密度。对于加载技术本身，提出了几个问题，因此研究了几种选择。例如，加载整个同种异体移植物还是将其分解成几个碎片更好？对于整个股骨头同种异体移植物，哪种注射方式效果最佳（通过软骨还是股骨颈）？注入的髂嵴骨髓的浓度（就间充质干细胞而言）应该是多少？用于同种异体移植物注射的骨髓取自接受骨浓缩手术患者的残余骨髓。用这种骨髓（浓缩和未浓缩的），我们测试了不同技术（注射和浸泡）以将干细胞加载到不同大小的同种异体移植物中：整块同种异体移植物、碎片或块状物（8或1立方厘米块状物）以及碎粒（125至8立方毫米）或微粒（1立方毫米）。我们还评估了在培养基中加载有间充质干细胞的自体移植物和同种异体移植物碎片中间充质干细胞的释放情况。
自体股骨头中间充质干细胞的浓度低于同一患者的髂嵴。然而，在未浓缩的情况下，用从髂嵴抽吸的骨髓，我们无法在股骨头同种异体移植物中加载与自体移植物中相同数量的间充质干细胞。骨髓的加载量（以及相应的间充质干细胞数量）取决于技术（注射、浸泡）以及同种异体移植物的体积和形状。将间充质干细胞加载到同种异体移植物中的接种效率随着骨髓中间充质干细胞的浓度而增加。使用浓缩骨髓，在手术室中可以使同种异体移植物加载比自体移植物更多的间充质干细胞，并且加载到同种异体移植物中的间充质干细胞数量是可预测的。
骨髓的加载量取决于技术（注射、浸泡）以及同种异体移植物的体积和形状。使用浓缩骨髓，同种异体移植物可以加载与股骨头自体移植物中数量相似或更多的间充质干细胞。
