1 Center for Orthopaedic and Trauma Surgery, Ingolstadt Hospital , Ingolstadt, Germany .
2 Department of Trauma, Hand and Reconstructive Surgery, Universitätsklinikum Jena , Jena, Germany .
Tissue Eng Part A. 2018 Feb;24(3-4):275-286. doi: 10.1089/ten.TEA.2016.0505. Epub 2017 Jul 19.
Human chondrocytes isolated from articular cartilage (AC) lesions as an alternative cell source to the standard nonweight-bearing notch biopsy site may hold clinical potential for cell-based therapies. The aim was to characterize human AC lesion site chondrocytes, compare them to notch chondrocytes, and evaluate their redifferentiation potential after monolayer expansion and subsequent three-dimensional (3D) alginate bead culture. Lesion chondrocytes from knee joints of 20 patients with International Cartilage Repair Society (ICRS) grade 3 and 4 cartilage defects were analyzed ex vivo or cultured in primary alginate bead culture, monolayer expansion, or redifferentiated in alginate culture following monolayer expansion. The mRNA expression of the types I, II, and X collagen, and the proteoglycan aggrecan was compared between the four groups. In addition, notch chondrocytes of nine patients were compared to lesion chondrocytes ex vivo. AC lesion chondrocytes displayed ex vivo a nondegenerative phenotype, characterized by a relatively high mRNA expression of aggrecan and type II and X collagen, but a low type I collagen expression and a low ratio of type I to II collagen mRNA expression. Compared to notch chondrocytes, the mRNA expression of aggrecan and type II collagen was comparable and the ratio of type I to II collagen mRNA expression was below 1 in both groups, indicating a functional chondrocyte phenotype. Dedifferentiation led to a significantly altered degenerative mRNA expression profile. Induced redifferentiation in alginate beads after monolayer expansion significantly improved the mRNA expression of aggrecan, the type I and II collagen, and the type I to II collagen ratio, compared to monolayer expansion only. These data suggested that redifferentiating lesion chondrocytes after monolayer expansion in alginate beads resulted in a pool of cells with greater chondrogenic potential, compared to expanded dedifferentiated chondrocytes. Collectively, these data suggest that ex vivo and redifferentiated lesion chondrocytes may hold nonutilized clinical potential for the tissue engineering of AC.
从关节软骨（AC）病变中分离的人软骨细胞作为标准非承重切迹活检部位的替代细胞来源，可能具有细胞治疗的临床潜力。目的是对人 AC 病变部位的软骨细胞进行特征分析，将其与切迹软骨细胞进行比较，并评估其在单层扩增和随后的三维（3D）藻酸盐珠培养后的再分化潜力。对 20 名患有国际软骨修复协会（ICRS）3 级和 4 级软骨缺损的患者膝关节的病变软骨细胞进行分析，在体外或在原代藻酸盐珠培养物中培养，或在单层扩增后在藻酸盐培养物中再分化。比较了这四组的 I 型、II 型和 X 型胶原蛋白以及蛋白聚糖聚集蛋白的 mRNA 表达。此外，还将 9 名患者的切迹软骨细胞与病变软骨细胞进行了比较。AC 病变软骨细胞在体外表现出非退行性表型，其特征是聚集蛋白和 II 型和 X 型胶原蛋白的 mRNA 表达相对较高，但 I 型胶原蛋白表达较低，I 型和 II 型胶原蛋白 mRNA 表达的比例较低。与切迹软骨细胞相比，两组的聚集蛋白和 II 型胶原蛋白的 mRNA 表达相当，I 型和 II 型胶原蛋白 mRNA 表达的比例均低于 1，表明具有功能性软骨细胞表型。去分化导致退行性 mRNA 表达谱发生显著改变。与仅单层扩增相比，在藻酸盐珠中单层扩增后诱导再分化可显著提高聚集蛋白、I 型和 II 型胶原蛋白以及 I 型和 II 型胶原蛋白比例的 mRNA 表达。这些数据表明，与单层扩增的去分化软骨细胞相比，在藻酸盐珠中单层扩增后的再分化病变软骨细胞产生了具有更大软骨形成潜力的细胞池。总之，这些数据表明，体外和再分化的病变软骨细胞可能具有未被利用的临床潜力，可用于 AC 的组织工程。
