P033 - Aptamer-Functionalized Bioscaffold Enhances Cartilage Repair by Improving Stem Cells Recruitment in Osteochondral Defects
Abstract
Purpose
Recruitment of endogenous stem cells has been considered as an alternative to cell injection/implantation in articular cartilage repair. The purpose of this study was to (1) develop a cartilage tissue engineering scaffold with clinically available biomaterials, and functionalize the scaffold with aptamer that specifically recognizes pluripotent stem cells, (2) determine whether this scaffold could recruit joint-resident mesenchymal stem cells (MSCs) when implanted in an osteochondral defect in a rabbit model, and examine the effects of cartilage regeneration.
Methods and Materials
The reinforced scaffold was fabricated by imbedding silk fibroin (SF) sponge into SF/hyaluronic acid (HA)-tyramine hydrogel, and characterized in vitro. A cylindrical osteochondral defect (3.2 mm wide × 4 mm deep) was created in trochlear grooves of rabbit knees. The rabbits were randomly assigned into 3 groups: aptamer Apt19s-functionalized scaffold group, scaffold only group, and control group. Animals were sacrificed at 6 and 12 weeks after transplantation. Repaired tissues were evaluated via gross examination, histological examination, and immunohistochemistry.
Results
In vitro, this aptamer-functionalized scaffold could recruit bone marrow-derived MSCs, and support cell adhesion. In vivo, the aptamer-functionalized scaffold enhanced cell homing in comparison to aptamer-free scaffold. The aptamer functionalized scaffold group also exhibited superior cartilage restoration when compared to scaffold only group and control group.
Conclusion
The Apt19s-functionalized scaffold exhibited the ability to recruit MSCs both in vitro and in vivo, and achieved better outcome of cartilage repair than scaffold only or control in osteochondral defect model. The findings demonstrate a promising strategy of using aptamer-functionalized bioscaffolds for restoration of chondral/osteochondral defects via aptamer-introduced homing of MSCs.
