A Novel Glycosaminoglycan Mimetic Scaffold for Cartilage Repair - diversity supplement

项目总结

Project Summary With the limited healing capability of articular cartilage, clinical intervention is necessary to prevent further articular cartilage damage and early onset of degenerative osteoarthritis. Current surgical procedures result in inadequate repair suffering from poor integration with surrounding hyaline cartilage and the formation of fibrocartilage instead of normal hyaline cartilage. The most frequently used reparative treatment for small symptomatic lesions of articular cartilage of the knee is microfracturing, where multiple holes are made in the subchondral bone allowing stem cells from the bone marrow to migrate to the joint surface and facilitate repair. However, in the long-term, this method does not result in the replacement of normal hyaline cartilage. The approach described here is to combine the surgical treatment of microfracturing, which will provide endogenous cells capable of chondrogenesis to the defect site, with a novel scaffold that mimics the cartilage extracellular matrix during development to promote chondrogenesis and cartilage tissue formation. During cartilage development, the major matrix components are collagens and proteoglycans, wherein the predominant glycosaminoglycans (GAGs) in the proteoglycans are chondroitin-6-sulfate and heparin sulfate. The pattern and degree of sulfation in these and other GAGs play an integral role in providing the necessary functionality/bioactivity for growth factor interactions in cartilage development. Typical synthetic biomaterials lack functional sites that would enable this interaction. This study will investigate a novel, semi-synthetic derivative of cellulose, which is one of the most abundant natural materials. Sodium cellulose sulfate (NaCS), which is water soluble and mimics the structure of GAG, will be fabricated into a scaffold and combined with microfracturing as a novel strategy for cartilage repair. In our studies to date, fully sulfated NaCS has shown promise in promoting chondrogenesis and accelerating the repair of osteochondral defects. We hypothesize that NaCS will impart functional qualities that are similar to GAGs, direct chondrogenesis and cartilage tissue formation. In the proposed supplement, two specific aims will be addressed that complement the ongoing studies in the parent grant. Aim 1 will Investigate chondrogenesis on NaCS-containing scaffolds and scaffold integration in vitro. The goal of this aim is to evaluate cartilage tissue formation and integration with surrounding host cartilage in a cartilage explant model. Aim 2 will investigate in vitro chondrogenesis and scaffold integration in physiologically-relevant conditions using a microfluidic device. Findings will also provide further mechanistic understanding of the NaCS containing scaffolds in repairing cartilage lesions.