Heat-Treated Porous Fluorapatite Scaffolds with Adipose Derived Stem Cells for Bone Regeneration

由高能量创伤引起的节段性骨丢失，如战场创伤，是威胁肢体的情况，但 可供选择的治疗方法有限。传统的治疗方法包括骨移植、带血管的骨 移植和同种异体移植。使用带血管的自体骨移植修复骨可以说是目前最好的方法， 因为修复过程将通过患者自己的组织和血液供应进行，这些组织和血液供应可以 在手术的时候。这消除了许多与同种异体移植和生物工程相关的不良后果。 骨替代物。然而，供者自体移植部位有限，因此其供应不能满足需求。它 还需要第二个手术部位，这可能会导致进一步的合并症。脱细胞同种异体移植 从身体来源获得的材料具有骨传导的优势。但是，它们是关联的 有宿主排斥和移植物加速吸收的风险。目前的生物工程移植物专注于提供 通过提供生物相容、可生物吸收和多孔支架来支持骨再生所需的基质 由羟基磷灰石、胶原和合成材料制成。现在很明显，生物工程 移植物还需要可靠的成骨祖细胞来源以及成骨信号才能有效 骨替代物。为了改进这些最初的设计，研究人员制作了新的支架，将 细胞外基质蛋白或生长因子，典型的骨形态发生蛋白(BMPs)，但有限 成功。通常情况下，支架的强度仍然是手术后承重的主要障碍。对这件事 最后，我们采用“凝胶浇注”工艺制备了一种完全互联的多孔氟磷灰石(FA)支架， 然后进行热处理以优化机械强度。由于这些表面是成骨的，它们还可以增强 成骨细胞的黏附、增殖和分化。有趣的是，这些支架还具有 在没有任何成骨信号的情况下将干细胞(脂肪干细胞)分化为成骨谱系(例如 外源性BMPs)。更值得注意的是，“凝胶浇注”技术允许定制所需的形状和 刚性脚手架的大小，以适应个别缺陷。因此，我们假设FA脚手架播种了一个 患者自己的脂肪组织来源的基质血管成分(SVF)干细胞将有能力 再生骨组织。这一假设将在三个目标上得到检验。特定目标1将调查 将产生的多孔氟磷灰石支架的机械、物理和降解性能 采用凝胶注模成型技术。特异性靶点2将量化体外黏附和分化特性 多孔性FA表面的SVF细胞。特殊目标3将研究FA支架的成骨潜力 在有和没有SVF的大鼠股骨髁部模型中。预计这种联合治疗SVF和 FA支架将为临床骨修复和骨修复提供潜在的“现成”支架材料 恢复和改善一些军事人员、退伍军人和平民的健康和生活质量。 好了！ 好了！

Segmental bone loss due to high-energy trauma, such as battlefield injuries, are limb-threatening conditions, but there are limited treatment options available. Conventional treatments include bone grafts, vascularized bone transplant, and allografts. Bone repair using vascularized autografts is arguably the best current approach, because the repair process will proceed with the patient’s own tissue and blood supply, which can be harvested at the time of surgery. This eliminates many adverse outcomes associated with allografts and bioengineered bone substitutes. However, donor autograft sites are limited, and thus, its supply cannot meet the demand. It also requires a second surgical site, which could result in further comorbidities. Decellularized allografts harvested from cadaveric sources have the advantage of being osteoconductive. However, they are associated with risk of host rejection and accelerated graft resorption. Current bioengineered grafts focus on providing the necessary matrix to support bone regeneration by providing biocompatible, bioresorbable, and porous scaffolds made from materials such as hydroxyapatite, collagen and synthetic materials. It is now clear that bioengineered grafts also need a reliable source of osteogenic progenitor cells as well as osteogenic signals to be effective bone substitutes. To improve upon these initial designs, researchers made new scaffolds that integrated extracellular matrix proteins or growth factors, typically bone morphogenetic proteins (BMPs), but with limited success. Often the strength of the scaffolding remains the main hurdle for weight-bearing after surgery. To this end, we fabricated a fully interconnecting porous fluorapatite (FA) scaffold by adopting a “gel-casting” process, and then heat-treating to optimize the mechanical strength. As these surfaces are osteogenic, they also enhance osteoblast adhesion, proliferation, and differentiation. Interestingly, these scaffolds also possess the ability to differentiate stem cells (adipose derive stem cells) to an osteogenic lineage without any osteogenic signals (e.g. exogenous BMPs). More notably, the “gel-casting” technique allows custom fabrication of desired shapes and sizes of rigid scaffoldings to fit individual defects. Thus, we hypothesize that FA scaffoldings seeded with a patient’s own adipose tissue-derived stromal vascular fraction (SVF) stem cells will have the ability to regenerate osseous tissue. This hypothesis will be tested in three aims. Specific Aim 1 will investigate the mechanical, physical, and degradation properties of the porous fluorapatite scaffolds, which will be generated by the gel-casting technique. Specific Aim 2 will quantify the in vitro adhesion and differentiation properties of the SVF cells on porous FA surfaces. Specific Aim 3 will investigate the osteogenic potential of the FA scaffolding with and without SVF in a rat femoral condyle model. It is expected that such combination treatment of SVF and FA scaffolds will provide a potential source of “off-the-shelf” scaffolding materials for clinical bone repair and regeneration and improve the health and quality of life for a number of military personnel, veterans, and civilians. ! !