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骨髓间充质干细胞构建的软骨组织中构建尺度对其组成和功能特性的影响。

The influence of construct scale on the composition and functional properties of cartilaginous tissues engineered using bone marrow-derived mesenchymal stem cells.

机构信息

Trinity Centre for Bioengineering, Department of Mechanical Engineering, School of Engineering, Trinity College, Dublin, Ireland.

出版信息

Tissue Eng Part A. 2012 Feb;18(3-4):382-96. doi: 10.1089/ten.TEA.2011.0145. Epub 2011 Nov 2.

Abstract

Engineering cartilaginous tissue of a scale necessary to treat defects observed clinically is a well-documented challenge in the field of cartilage tissue engineering. The objective of this study was to determine how the composition and mechanical properties of cartilaginous tissues that are engineered by using bone marrow-derived mesenchymal stem cells (MSCs) depend on the scale of the construct. Porcine bone marrow-derived MSCs were encapsulated in agarose hydrogels, and constructs of different cylindrical geometries (Ø4×1.5 mm; Ø5×3 mm; Ø6×4.5 mm; Ø8×4.5 mm) were fabricated and maintained in a chemically defined serum-free medium supplemented with transforming growth factor-β3 for 42 days. Total sulfated glycosaminoglycan (sGAG) accumulation by day 42 increased from 0.14% w/w to 0.88% w/w as the construct geometry increased from Ø4×1.5 to Ø8×4.5 mm, with collagen accumulation increasing from 0.31% w/w to 1.62% w/w. This led to an increase in the dynamic modulus from 90.81 to 327.51 kPa as the engineered tissue increased in scale from Ø4×1.5 to Ø8×4.5 mm. By decreasing the external oxygen tension from 20% to 5%, it was possible to achieve these higher levels of mechanical functionality in the smaller engineered tissues. Constructs were then sectioned into smaller subregions to quantify the spatial accumulation of extracellular matrix components, and a model of oxygen diffusion and consumption was used to predict spatial gradients in oxygen concentration throughout the construct. sGAG accumulation was always highest in regions where oxygen concentration was predicted to be lowest. In addition, as the size of the engineered construct increased, different regions of the construct preferentially supported either sGAG or collagen accumulation, thus suggesting that gradients in regulatory factors other than oxygen were playing a role in determining levels of collagen synthesis. The identification of such factors and the means to control their spatial concentration within developing tissues represents a central challenge in engineering large cartilaginous grafts.

摘要

用骨髓间充质干细胞(MSCs)构建工程化软骨组织以治疗临床上观察到的缺陷是软骨组织工程领域中的一个难题。本研究旨在确定通过 MSCs 构建的软骨组织的组成和力学性能如何依赖于构建体的规模。将猪骨髓来源的 MSCs 包封在琼脂糖水凝胶中,并制造出不同圆柱几何形状(Ø4×1.5mm;Ø5×3mm;Ø6×4.5mm;Ø8×4.5mm)的构建体,并在补充转化生长因子-β3 的无血清化学定义培养基中维持 42 天。到第 42 天,总硫酸化糖胺聚糖(sGAG)的积累从 0.14%w/w 增加到 0.88%w/w,构建体几何形状从 Ø4×1.5mm 增加到 Ø8×4.5mm,胶原积累从 0.31%w/w 增加到 1.62%w/w。这导致随着工程化组织从 Ø4×1.5mm 增加到 Ø8×4.5mm,动态模量从 90.81kPa 增加到 327.51kPa。通过将外部氧张力从 20%降低到 5%,可以在较小的工程化组织中实现这些更高水平的机械功能。然后将构建体切成较小的子区域,以量化细胞外基质成分的空间积累,并使用氧扩散和消耗模型来预测整个构建体中的氧浓度空间梯度。sGAG 的积累总是在预测氧浓度最低的区域最高。此外,随着工程化构建体尺寸的增加,构建体的不同区域优先支持 sGAG 或胶原的积累,这表明除氧以外的调节因子的梯度在决定胶原合成水平方面发挥作用。确定这些因素以及控制其在发育组织内空间浓度的方法是构建大软骨移植物的核心挑战。

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