CNRS UMR 7365 - Lorraine University, Ingénierie Moléculaire et Physiopathologie Articulaire (IMoPA), Biopôle, Vandœuvre-lès-Nancy, France.
Fédération de Recherche 3209, Bioingénierie Moléculaire Cellulaire et Thérapeutique, Vandœuvre-lès-Nancy, France.
J Tissue Eng Regen Med. 2018 Feb;12(2):360-369. doi: 10.1002/term.2461. Epub 2017 Aug 22.
Scaffolds laden with stem cells are a promising approach for articular cartilage repair. Investigations have shown that implantation of artificial matrices, growth factors or chondrocytes can stimulate cartilage formation, but no existing strategies apply mechanical stimulation on stratified scaffolds to mimic the cartilage environment. The purpose of this study was to adapt a spraying method for stratified cartilage engineering and to stimulate the biosubstitute. Human mesenchymal stem cells from bone marrow were seeded in an alginate (Alg)/hyaluronic acid (HA) or Alg/hydroxyapatite (Hap) gel to direct cartilage and hypertrophic cartilage/subchondral bone differentiation, respectively, in different layers within a single scaffold. Homogeneous or composite stratified scaffolds were cultured for 28 days and cell viability and differentiation were assessed. The heterogeneous scaffold was stimulated daily. The mechanical behaviour of the stratified scaffolds were investigated by plane-strain compression tests. Results showed that the spraying process did not affect cell viability. Moreover, cell differentiation driven by the microenvironment was increased with loading: in the layer with Alg/HA, a specific extracellular matrix of cartilage, composed of glycosaminoglycans and type II collagen was observed, and in the Alg/Hap layer more collagen X was detected. Hap seemed to drive cells to a hypertrophic chondrocytic phenotype and increased mechanical resistance of the scaffold. In conclusion, mechanical stimulations will allow for the production of a stratified biosubstitute, laden with human mesenchymal stem cells from bone marrow, which is capable in vivo to mimic all depths of chondral defects, thanks to an efficient combination of stem cells, biomaterial compositions and mechanical loading.
负载干细胞的支架是关节软骨修复的一种很有前途的方法。研究表明，植入人工基质、生长因子或软骨细胞可以刺激软骨形成，但现有的策略都没有在分层支架上施加机械刺激来模拟软骨环境。本研究旨在调整一种用于分层软骨工程的喷涂方法，并对生物替代物进行刺激。将骨髓间充质干细胞接种在藻酸盐（Alg）/透明质酸（HA）或 Alg/羟基磷灰石（Hap）凝胶中，以分别在单个支架的不同层中引导软骨和肥大软骨/软骨下骨分化。均匀或复合分层支架培养 28 天，评估细胞活力和分化情况。对异质支架进行每日刺激。通过平面应变压缩试验研究分层支架的力学性能。结果表明，喷涂过程不会影响细胞活力。此外，负载刺激增加了由微环境驱动的细胞分化：在 Alg/HA 层中，观察到由糖胺聚糖和 II 型胶原组成的特定软骨细胞外基质，而在 Alg/Hap 层中检测到更多的胶原 X。Hap 似乎将细胞驱动为肥大软骨细胞表型，并增加了支架的机械阻力。总之，机械刺激将允许生产负载骨髓间充质干细胞的分层生物替代物，由于干细胞、生物材料组成和机械加载的有效结合，该替代物能够在体内模拟所有深度的软骨缺损。
