Mount Sinai Hospital, 600 University Avenue, Suite 476C, Toronto M5G 1X5, Canada.
Clin Orthop Relat Res. 2011 Oct;469(10):2785-95. doi: 10.1007/s11999-011-1856-4.
We developed a tissue-engineered biphasic cartilage bone substitute construct which has been shown to integrate with host cartilage and differs from autologous osteochondral transfer in which integration with host cartilage does not occur.
QUESTIONS/PURPOSES: (1) Develop a reproducible in vitro model to study the mechanisms regulating tissue-engineered cartilage integration with host cartilage, (2) compare the integrative properties of tissue-engineered cartilage with autologous cartilage and (3) determine if chondrocytes from the in-vitro formed cartilage migrate across the integration site.
A biphasic construct was placed into host bovine osteochondral explant and cultured for up to 8 weeks (n = 6 at each time point). Autologous osteochondral implants served as controls (n = 6 at each time point). Integration was evaluated histologically, ultrastructurally, biochemically and biomechanically. Chondrocytes used to form cartilage in vitro were labeled with carboxyfluorescein diacetate which allowed evaluation of cell migration into host cartilage.
Histologic assessment demonstrated that tissue-engineered cartilage integrated over time, unlike autologous osteochondral implant controls. Biochemically there was an increase in collagen content of the tissue-engineered implant over time but was well below that for native cartilage. Integration strength increased between 4 and 8 weeks as determined by a pushout test. Fluorescent cells were detected in the host cartilage up to 1.5 mm from the interface demonstrating chondrocyte migration.
Tissue-engineered cartilage demonstrated improved integration over time in contrast to autologous osteochondral implants. Integration extent and strength increased with culture duration. There was chondrocyte migration from tissue-engineered cartilage to host cartilage.
This in vitro integration model will allow study of the mechanism(s) regulating cartilage integration. Understanding this process will facilitate enhancement of cartilage repair strategies for the treatment of chondral injuries.
我们开发了一种组织工程化的双相软骨骨替代物构建体，该构建体已被证明可与宿主软骨整合，与自体软骨移植不同，自体软骨移植不会与宿主软骨整合。
问题/目的：（1）建立一种可重复的体外模型来研究调节组织工程化软骨与宿主软骨整合的机制，（2）比较组织工程化软骨与自体软骨的整合特性，（3）确定体外形成的软骨中的软骨细胞是否迁移到整合部位。
将双相构建体放置在宿主牛骨软骨外植体中，并培养长达 8 周（每个时间点 n = 6）。自体软骨移植作为对照（每个时间点 n = 6）。通过组织学、超微结构、生物化学和生物力学评估整合。用于体外形成软骨的软骨细胞用羧基荧光素二乙酸酯标记，允许评估细胞向宿主软骨的迁移。
组织学评估表明，组织工程化软骨随时间逐渐整合，与自体软骨移植对照不同。生物化学分析表明，随着时间的推移，组织工程化植入物的胶原蛋白含量增加，但远低于天然软骨。通过推出试验确定，整合强度在 4 至 8 周之间增加。荧光细胞在宿主软骨中检测到距离界面 1.5 毫米处，证明了软骨细胞的迁移。
与自体软骨移植相比，组织工程化软骨随时间显示出更好的整合。随着培养时间的延长，整合程度和强度增加。有软骨细胞从组织工程化软骨向宿主软骨迁移。
这种体外整合模型将允许研究调节软骨整合的机制。了解这一过程将有助于增强软骨修复策略，以治疗软骨损伤。
