Department of Surgery, Laboratory of Bioregenerative Medicine & Surgery, Division of Plastic Surgery, Weill Cornell Medical College, New York, New York, USA.
Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York, USA.
J Tissue Eng Regen Med. 2022 Sep;16(9):825-835. doi: 10.1002/term.3332. Epub 2022 Jun 11.
A major challenge to the clinical translation of tissue-engineered ear scaffolds for ear reconstruction is the limited auricular chondrocyte (hAuC) yield available from patients. Starting with a relatively small number of chondrocytes in culture results in dedifferentiation and loss of phenotype with subsequent expansion. To significantly decrease the number of chondrocytes required for human elastic cartilage engineering, we co-cultured human mesenchymal stem cells (hMSCs) with HAuCs to promote healthy elastic cartilage formation. HAuCs along with human bone marrow-derived hMSCs were encapsulated into 1% Type I collagen at 25 million/mL total cell density with different ratios (HAuCs/hMSCs: 10/90, 25/75, 50/50) and then injected into customized 3D-printed polylactic acid (PLA) ridged external scaffolds, which simulate the shape of the auricular helical rim, and implanted subcutaneously in nude rats for 1, 3 and 6 months. The explanted constructs demonstrated near complete volume preservation and topography maintenance of the ridged "helical" feature after 6 months with all ratios. Cartilaginous appearing tissue formed within scaffolds by 3 months, verified by histologic analysis demonstrating mature elastic cartilage within the constructs with chondrocytes seen in lacunae within a Type II collagen and proteoglycan-enriched matrix, and surrounded by a neoperichondrial external layer. Compressive mechanical properties comparable to human elastic cartilage were achieved after 6 months. Co-implantation of hAuCs and hMSCs in collagen within an external scaffold efficiently produced shaped human elastic cartilage without volume loss even when hAuC comprised only 10% of the implanted cell population, marking a crucial step toward the clinical translation of auricular tissue engineering.
组织工程化耳朵支架用于耳朵重建的临床转化面临的一个主要挑战是，从患者中获得的耳软骨细胞（hAuC）数量有限。在培养中起始时软骨细胞数量相对较少，会导致去分化和表型丧失，随后发生扩增。为了显著减少用于人弹性软骨工程的软骨细胞数量，我们将人骨髓间充质干细胞（hMSCs）与 hAuC 共培养，以促进健康弹性软骨的形成。将 hAuC 与人类骨髓来源的 hMSCs 以不同比例（hAuC/hMSCs：10/90、25/75、50/50）封装到 1%的 I 型胶原中，细胞密度为 2500 万/mL，然后将其注入定制的 3D 打印聚乳酸（PLA）脊状外部支架中，这些支架模拟耳廓螺旋边缘的形状，并植入裸鼠皮下 1、3 和 6 个月。在 6 个月后，所有比例的实验都显示出了接近完全的体积保存和脊状“螺旋”特征的形貌维持。3 个月后，支架内形成了软骨样组织，通过组织学分析证实了这一点，其中构建体内部存在成熟的弹性软骨，软骨细胞位于 II 型胶原和糖胺聚糖丰富的基质的陷窝内，并被新生的软骨外层包围。在 6 个月后，获得了与人类弹性软骨相当的压缩力学性能。hAuC 和 hMSCs 在外部支架中的胶原共植入可以有效地产生具有形状的人弹性软骨，而不会发生体积丢失，即使 hAuC 仅占植入细胞群体的 10%，这标志着向耳廓组织工程的临床转化迈出了关键一步。
