Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, United States.
Department of Neurological Surgery, University of Washington, Seattle, Washington 98195, United States.
ACS Appl Mater Interfaces. 2024 Jun 5;16(22):28263-28275. doi: 10.1021/acsami.4c06013. Epub 2024 May 24.
Intervertebral disc degeneration (IDD) is a progressive condition and stands as one of the primary causes of low back pain. Cell therapy that uses nucleus pulposus (NP)-like cells derived from human induced pluripotent stem cells (hiPSCs) holds great promise as a treatment for IDD. However, the conventional two-dimensional (2D) monolayer cultures oversimplify cell-cell interactions, leading to suboptimal differentiation efficiency and potential loss of phenotype. While three-dimensional (3D) culture systems like Matrigel improve hiPSC differentiation efficiency, they are limited by animal-derived materials for translation, poorly defined composition, short-term degradation, and high cost. In this study, we introduce a new 3D scaffold fabricated using medical-grade chitosan with a high degree of deacetylation. The scaffold features a highly interconnected porous structure, near-neutral surface charge, and exceptional degradation stability, benefiting iPSC adhesion and proliferation. This scaffold remarkably enhances the differentiation efficiency and allows uninterrupted differentiation for up to 25 days without subculturing. Notably, cells differentiated on the chitosan scaffold exhibited increased cell survival rates and upregulated gene expression associated with extracellular matrix secretion under a chemically defined condition mimicking the challenging microenvironment of intervertebral discs. These characteristics qualify the chitosan scaffold-cell construct for direct implantation, serving as both a structural support and a cellular source for enhanced stem cell therapy for IDD.
椎间盘退变（IDD）是一种进行性疾病，是腰痛的主要原因之一。使用源自人诱导多能干细胞（hiPSC）的髓核样细胞的细胞疗法有望成为治疗 IDD 的一种方法。然而，传统的二维（2D）单层培养过于简化了细胞-细胞相互作用，导致分化效率不理想和表型潜在丧失。虽然像 Matrigel 这样的三维（3D）培养系统可以提高 hiPSC 分化效率，但它们受到动物源性材料用于转化、组成不明确、短期降解和高成本的限制。在这项研究中，我们引入了一种使用高脱乙酰度的医用级壳聚糖制造的新型 3D 支架。该支架具有高度互联的多孔结构、接近中性的表面电荷和出色的降解稳定性，有利于 iPSC 的黏附和增殖。这种支架显著提高了分化效率，并允许在无需传代的情况下不间断地分化长达 25 天。值得注意的是，在模拟椎间盘挑战性微环境的化学定义条件下，在壳聚糖支架上分化的细胞表现出更高的细胞存活率和上调与细胞外基质分泌相关的基因表达。这些特性使壳聚糖支架-细胞构建体有资格直接植入，作为增强干细胞治疗 IDD 的结构支撑和细胞来源。
