Development and characterization of decellularized meniscus-derived bioscaffolds

Abstract Meniscus tears are one of the most common musculoskeletal injuries, but treatment options remain limited. Recognizing that the extracellular matrix (ECM) provides cell-instructive cues that can direct cell differentiation, the current study focused on the development and characterization of bioscaffolds derived from decellularized meniscus with a view towards future tissue-engineering applications. The first phase of research validated a new decellularization protocol for porcine meniscus that avoided the use of anionic detergents. The inner and outer regions of the meniscus were processed separately, and cell extraction, collagen content, and glycosaminoglycan (GAG) content were characterized in comparison to a published protocol also involving treatment with the non-ionic detergent Triton X-100 and enzymatic digestion with DNase and RNase. Our new protocol effectively removed cellular content while preserving key ECM constituents including glycosaminoglycans (GAGs) in both the inner and outer meniscus regions. Next, the cell-instructive effects of the decellularized ECM generated with our new protocol were probed by encapsulating human adipose-derived stromal cells (ASCs) within alginate beads incorporating pepsin-digested decellularized inner meniscus (DIM) or decellularized outer meniscus (DOM). Viability staining confirmed that the encapsulated ASCs remained highly viable over 28 days in culture in proliferation or chondrogenic differentiation media. Compared to alginate alone, the viable cell density within the alginate beads at 28 days was significantly higher in the beads incorporating DIM under both media conditions, as well as in the beads incorporating DOM in proliferation medium. In addition, immunofluorescence staining supported that the incorporation of the pepsin-digested ECM within the alginate enhanced fibrochondrogenic ECM marker expression in the samples cultured in chondrogenic differentiation medium. Overall, these studies provide new insight supporting that decellularized meniscus ECM can be harnessed to direct cell phenotype and function towards the goal of developing tissue-specific bioinks for tissue-engineering applications.