Engineered Decellularized Tendon Matrix Putty Preserves Native Tendon Bioactivity to Promote Cell Proliferation and Enthesis Repair

Rotator cuff tears are a common soft tissue injury that can significantly decrease function of the shoulder and cause severe pain. Despite progress in surgical technique, rotator cuff repairs (RCRs) do not always heal efficiently. Many failures occur at the bone-tendon interface as a result of poor healing capacity of the tendon and failure to regenerate the native histological anatomy of the enthesis. While allografts are commercially available, clinical use is limited as they do not stimulate tissue regeneration and are associated with a structural failure of up to 40% in re-tear cases. Novel tissue engineering strategies are being developed with promise, but most involve addition of cells and/or growth factors which extends the timeline for clinical translation. Thus, there exists a significant unmet clinical need for easily translatable surgical augmentation approaches that can improve healing in RCR. Here we describe the development of a decellularized tendon matrix (DTM) putty that preserves native tendon bioactivity using a novel processing technique. In vitro, DTM promoted proliferation of tenocytes and adipose-derived stem cells with an increase in expression-specific transcription factors seen during enthesis development, Scleraxis and Sox9. When placed in a rabbit model of a chronic rotator cuff tear, DTM improved histological tissue repair by promoting calcification at the bone-tendon interface more similar to the normal fibrocartilaginous enthesis. Taken together, these data indicate that the engineered DTM putty retains a pro-regenerative bioactivity that presents a promising translational strategy for improving healing at the enthesis.