■生物工程软骨是一种正在发展的修复软骨缺损的治疗剂。基质必须富含II型胶原蛋白和聚集蛋白聚糖,并且具有机械能力,承受压缩和剪切载荷。天然关节软骨的生物力学特性取决于由3个区域组成的区域结构:浅表,中间,和深。浅区软骨细胞产生润滑性蛋白聚糖-4,而深层软骨细胞产生X型胶原,可以整合到软骨下骨中。细胞数量扩增后,区域和软骨形成表达丧失。当前的基于细胞的疗法具有有限的再生天然软骨的带状结构的能力。
■高密度传代的浅层和深层软骨细胞都可以形成富含II型胶原蛋白和聚集蛋白聚糖的生物工程软骨;然而,只有传代的浅表区来源的软骨细胞会表达浅表区特异性蛋白聚糖-4,只有传代的深区来源的软骨细胞会表达深区特异性X型胶原。
■对照实验室研究。
■从牛关节中分离出浅层和深层软骨细胞,和区域亚群分别在二维培养中扩展。在第2代,接种浅层和深层软骨细胞,分开,在琼脂糖孔中的无支架3维培养中,并在再分化培养基中培养。
■单层扩增导致传代浅层和深层软骨细胞中蛋白聚糖-4和X型胶原的表达丧失,分别。到第2代,浅表和深区软骨细胞对去分化分子I型胶原和生腱蛋白C的表达相似。浅表和深区软骨细胞的再分化导致两种传代软骨细胞群体中II型胶原和聚集蛋白聚糖的表达。然而,只有再分化的深部软骨细胞表达X型胶原,只有再分化的浅表区软骨细胞表达和分泌蛋白聚糖-4。此外,与浅表软骨细胞相比,再分化的深层软骨细胞产生了更厚,更坚固的组织。
■来自传代区域软骨细胞的主要表型的概述引入了一种类似于天然软骨的区域特异性生物学特性的软骨功能生物工程的新方法。
■区域软骨细胞中主要表型的概述可能是定制生物工程软骨以具有区域特异性表达的可能方法。
UNASSIGNED: Bioengineered cartilage is a developing therapeutic to repair cartilage defects. The matrix must be rich in collagen type II and aggrecan and mechanically competent, withstanding compressive and shearing loads. Biomechanical properties in native articular cartilage depend on the zonal architecture consisting of 3 zones: superficial, middle, and deep. The superficial zone chondrocytes produce lubricating proteoglycan-4, whereas the deep zone chondrocytes produce collagen type X, which allows for integration into the subchondral bone. Zonal and chondrogenic expression is lost after cell number expansion. Current cell-based therapies have limited capacity to regenerate the zonal structure of native cartilage.
UNASSIGNED: Both passaged superficial and deep zone chondrocytes at high density can form bioengineered cartilage that is rich in collagen type II and aggrecan; however, only passaged superficial zone-derived chondrocytes will express superficial zone-specific proteoglycan-4, and only passaged deep zone-derived chondrocytes will express deep zone-specific collagen type X.
UNASSIGNED: Controlled laboratory study.
UNASSIGNED: Superficial and deep zone chondrocytes were isolated from bovine joints, and zonal subpopulations were separately expanded in 2-dimensional culture. At passage 2, superficial and deep zone chondrocytes were seeded, separately, in scaffold-free 3-dimensional culture within agarose wells and cultured in redifferentiation media.
UNASSIGNED: Monolayer expansion resulted in loss of expression for proteoglycan-4 and collagen type X in passaged superficial and deep zone chondrocytes, respectively. By passage 2, superficial and deep zone chondrocytes had similar expression for dedifferentiated molecules collagen type I and tenascin C. Redifferentiation of both superficial and deep zone chondrocytes led to the expression of collagen type II and aggrecan in both passaged chondrocyte populations. However, only redifferentiated deep zone chondrocytes expressed collagen type X, and only redifferentiated superficial zone chondrocytes expressed and secreted proteoglycan-4. Additionally, redifferentiated deep zone chondrocytes produced a thicker and more robust tissue compared with superficial zone chondrocytes.
UNASSIGNED: The recapitulation of the primary phenotype from passaged zonal chondrocytes introduces a novel method of functional bioengineering of cartilage that resembles the zone-specific biological properties of native cartilage.
UNASSIGNED: The recapitulation of the primary phenotype in zonal chondrocytes could be a possible method to tailor bioengineered cartilage to have zone-specific expression.