Background Mesenchymal stromal cells (MSCs) are widely used in clinical trials for bone repair and regeneration. Despite previous evidence showing a prominent osteogenic potential of 2D cultured CD271 enriched MSCs, the osteogenic potential of CD271 enriched cells cultured on 3D scaffold is unknown. Apatite-wollastonite glass ceramic (A-W) is an osteoconductive biomaterial shown to be compatible with MSCs. This is the first study comparing the attachment, growth kinetics, and osteogenic potential of two MSC populations, namely heterogeneous plastic adherence MSCs (PA-MSCs) and CD271-enriched MSCs (CD271-MSCs), when cultured on A-W 3D scaffold. Results The paired MSC populations were assessed for their attachment, growth kinetics and ALP activity using confocal and scanning electron microscopy and the quantifications of DNA contents and p-nitrophenyl (pNP) production respectively. While the PA-MSCs and CD271-MSCs had similar expansion and tri-lineage differentiation capacity during standard 2D culture, they showed different proliferation kinetics when seeded on the A-W scaffolds. PA-MSCs displayed a well-spread attachment with more elongated morphology compared to CD271- MSCs, signifying a different level of interaction between the cell populations and the scaffold surface. Following scaffold seeding PA-MSCs fully integrated into the scaffold surface and showed a stronger propensity for osteogenic differentiation as indicated by higher ALP activity than CD271-MSCs. Furthermore, A-W scaffold seeded uncultured non-enriched bone marrow mononuclear cells also demonstrated a higher proliferation rate and greater ALP activity compared to their CD271-enriched counterpart. Conclusions Our findings suggest that CD271-positive enrichment of a population is not beneficial for osteogenesis when the cells are seeded on A-W scaffold. Furthermore, unselected heterogeneous MSCs or BMMNCs are more promising for A-W scaffold based bone regeneration. This leads to a conclusion of broader clinical relevance for tissue engineering: on the basis of our observations here the osteogenic potential observed in 2D cell culture should not be considered indicative of likely performance in a 3D scaffold based system, even when one of the cell populations is effectively a subset of the other.

中文翻译：

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在磷灰石-硅灰石 3D 支架上培养的异质和富含 CD271 的间充质基质细胞的成骨潜力。

背景 间充质基质细胞 (MSCs) 广泛用于骨修复和再生的临床试验。尽管先前的证据显示 2D 培养的富含 CD271 的 MSCs 具有显着的成骨潜力，但在 3D 支架上培养的富含 CD271 的细胞的成骨潜力尚不清楚。磷灰石-硅灰石玻璃陶瓷 (AW) 是一种与 MSC 相容的骨传导性生物材料。这是第一项比较在 AW 3D 支架上培养时，两种 MSC 种群的附着、生长动力学和成骨潜力的研究，即异质塑料粘附 MSC (PA-MSC) 和富含 CD271 的 MSC (CD271-MSC)。结果评估了成对的 MSC 群体的附着情况，使用共聚焦和扫描电子显微镜的生长动力学和 ALP 活性以及 DNA 含量和对硝基苯 (pNP) 生产的量化分别。虽然 PA-MSCs 和 CD271-MSCs 在标准 2D 培养过程中具有相似的扩增和三向分化能力，但它们在 AW 支架上接种时表现出不同的增殖动力学。与 CD271-MSCs 相比，PA-MSCs 显示出具有更细长形态的广泛附着，表明细胞群和支架表面之间的相互作用水平不同。在支架接种后，PA-MSCs 完全整合到支架表面并显示出更强的成骨分化倾向，这由比 CD271-MSCs 更高的 ALP 活性表明。此外，与富含 CD271 的对应物相比，接种 AW 支架的未培养非富集骨髓单核细胞也表现出更高的增殖率和更强的 ALP 活性。结论 我们的研究结果表明，当细胞接种在 AW 支架上时，群体的 CD271 阳性富集对成骨无益。此外，未选择的异质 MSCs 或 BMMNCs 更有希望用于基于 AW 支架的骨再生。这导致了组织工程更广泛的临床相关性的结论：根据我们在这里的观察，在 2D 细胞培养中观察到的成骨潜力不应被视为指示基于 3D 支架的系统中的可能性能，即使其中一个细胞群实际上是另一个的子集。