24.1.8 - Exploration of Repopulation and Remodeling of Acellular Meniscus Grafts
- K. Lydon (Rochester, US)
- C. Struijk (Rochester, US)
- K. Lydon (Rochester, US)
- M. Husen (Rochester, US)
- P. Verdonk (Gent-Zwijnaarde, BE)
- J. Michielsen (Antwerp, BE)
- A. Krych (Rochester, US)
- D. Saris (Rochester, US)
Abstract
Purpose
Meniscus replacement using acellular scaffolds (CMI) and allografts (meniscus allograft transplantation) are established treatment options when meniscus repair is unfeasible. Outcomes show satisfying mid-to long-term pain relief while 70% of grafts show size reduction suggesting vitality issues such as incomplete integration in the host. Analysis of in vivo biopsies show evidence of cellular repopulation while it remains controversial to what extent. Further research is needed to elucidate meniscus repopulation and remodeling to enhance meniscus tissue regeneration. We investigated in-vitro scaffold repopulation and neo-tissue formation using a novel human tissue model. This “donut and hole” model allows for the analysis of specific repopulation features such as cell types and cell migration direction.
Methods and Materials
Human meniscus tissue from patients undergoing total knee arthroplasty, allografts (JRF Ortho®) and CMI (Stryker), were obtained, cut using an 8- and 4-mm circular biopsy punch and reconstructed according to Fig.1. Tissue constructs were cultured up to 40 days in DMEM and analyzed using LIVE/DEAD assay (ThermoFisher) and histology (SafraninO and H&E).
Results
At day 0 and 7, the presence of living cells was limited to the living meniscus samples. On day 14, living cells appear at the interface of the acellular allograft. On later timepoints, cells repopulate the surface of the allograft tissue, this was not observed for the CMI. On day 40, cells derived from the living meniscus tissue repopulated the superficial layers of the allografts while deep tissue repopulation was absent (Fig.1). Remarkably, tissue construct 1A showed earlier and more extensive repopulation in comparison with construct 1B while it is generally accepted that cells involved in meniscus graft repopulation originate from the adjacent synovium (Fig.2)(Arnocszky 1992).
Conclusion
Initial results show cellular ingrowth and time dependent repopulation of the frozen allograft which suggests this in-vitro model will allow us to investigate cellular repopulation and remodeling of acellular scaffolds and allografts.