Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, 1151 Richmond St, London, Ontario, N6A 5C1, Canada.
Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, 1151 Richmond St, London, Ontario, N6A 5C1, Canada.
Biomaterials. 2021 Aug;275:120978. doi: 10.1016/j.biomaterials.2021.120978. Epub 2021 Jun 17.
With the goal of establishing a new clinically-relevant bioscaffold format to enable the delivery of high densities of human adipose-derived stromal cells (ASCs) for applications in soft tissue regeneration, a novel "cell-assembly" method was developed to generate robust 3-D scaffolds comprised of fused networks of decellularized adipose tissue (DAT)-derived beads. In vitro studies confirmed that the assembly process was mediated by remodelling of the extracellular matrix by the seeded ASCs, which were well distributed throughout the scaffolds and remained highly viable after 8 days in culture. The ASC density, sulphated glycosaminoglycan content and scaffold stability were enhanced under culture conditions that included growth factor preconditioning. In vivo testing was performed to compare ASCs delivered within the cell-assembled DAT bead foams to an equivalent number of ASCs delivered on a previously-established pre-assembled DAT bead foam platform in a subcutaneous implant model in athymic nude mice. Scaffolds were fabricated with human ASCs engineered to stably co-express firefly luciferase and tdTomato to enable long-term cell tracking. Longitudinal bioluminescence imaging showed a significantly stronger signal associated with viable human ASCs at timepoints up to 7 days in the cell-assembled scaffolds, although both implant groups were found to retain similar densities of human ASCs at 28 days. Notably, the infiltration of CD31 murine endothelial cells was enhanced in the cell-assembled implants at 28 days. Moreover, microcomputed tomography angiography revealed that there was a marked reduction in vascular permeability in the cell-assembled group, indicating that the developing vascular network was more stable in the new scaffold format. Overall, the novel cell-assembled DAT bead foams represent a promising platform to harness the pro-regenerative paracrine functionality of human ASCs and warrant further investigation as a clinically-translational approach for volume augmentation.
为了建立一种新的临床相关生物支架形式，以实现高密度的人脂肪来源基质细胞（ASCs）的递送，用于软组织再生应用，开发了一种新的“细胞组装”方法，以生成由去细胞化脂肪组织（DAT）衍生珠的融合网络组成的坚固 3-D 支架。体外研究证实，组装过程是由接种的 ASC 重塑细胞外基质介导的，ASC 均匀分布在支架中，在培养 8 天后仍保持高度活力。在包括生长因子预处理的培养条件下，可提高 ASC 密度、硫酸化糖胺聚糖含量和支架稳定性。进行了体内测试，以比较在细胞组装 DAT 珠泡内递送的 ASC 与在先前建立的预组装 DAT 珠泡平台上递送的相同数量的 ASC 在无胸腺裸鼠皮下植入模型中的效果。使用稳定共表达萤火虫荧光素和 tdTomato 的人 ASC 来制造支架，以实现长期细胞跟踪。纵向生物发光成像显示，在细胞组装支架中，与活的人 ASC 相关的信号在长达 7 天的时间点上显著增强，尽管在 28 天时，两个植入组都发现保留了相似密度的人 ASC。值得注意的是，在细胞组装植入物中，CD31 鼠内皮细胞的浸润在 28 天时增强。此外，微计算机断层血管造影显示，细胞组装组的血管通透性明显降低，表明新支架形式中的新生血管网络更稳定。总体而言，新型细胞组装 DAT 珠泡代表了一种有前途的平台，可以利用人 ASC 的促再生旁分泌功能，并值得进一步研究，作为一种体积增加的临床转化方法。
