M. P. Murphy1, M. Lopez1, R. C. Ransom1, O. Marecic1, R. E. Brewer1, L. S. Koepke1, S. Mascharak1, C. F. Chan1, M. T. Longaker1 1Stanford University,Surgery,Palo Alto, CA, USA
Introduction: Currently there are no effective strategies for regenerating articular cartilage in diseases such as osteoarthritis (OA). Our group has utilized the mouse model to study the effects of surgical, chemical and cellular manipulation in articular cartilage regeneration. We aim to understand the effects of surgical, chemical and cellular manipulation in articular cartilage regeneration in a novel xenograft human model.
Methods: We transplanted the phalanges of 18-week old fetal specimens subcutaneously in the dorsum of immuno-compromised NSG P3 mice. After we confirmed viabiliy of the human xenograft using MRI, microCT and on gross inspection we performed microfracture (MF) surgery on the articular joints. Histological composition was assessed using Movat’s Pentachrome stain and Safranin O/Fast green stain. Immunohistochemistry (IHC) was performed assessing levels of Col 1, 2, 10 and MMP13. Proliferation was assessed with EdU labelling in histology and intracellular FACS.
Results: We successfully developed a model of investigating the effects of surgical manipulation on human articular cartilage regeneration. (Figure 1) Following 6 weeks of implantation the xenograft had grown in size. The microCT images show calcification and MRI show viable articular cartilage. We have found that similar to our mouse model, fibrocartilage forms after MF. On histology and IHC we have determined the difference between normal articular cartilage and MF tissue. Cellular proliferation increases following injury.
Conclusion: We believe that our surgical technique and topical factors including BMP2 and Avastin will provide regenerative surgeons with a new approach to treating OA. We will further augment these factors with induced SSC from human Adipose-derived Stromal Cells. Our findings provide us with a "preclinical" human model that can be utilised to effectively investigate strategies for articular cartilage regeneration.
