Enhancement of rotator cuff XXXX with injectable periosteum progenitor cells- @entity9040 hydrogel in vivo.

@entity7028 @entity9040 @entity95 @entity79 @entity397 @entity970 @entity968
PURPOSE: The fixation and incorporation of @entity397 rotator cuff tendon to bone is a major concern in rotator cuff repair surgery. Rotator cuff repair usually fails at the tendon-bone interface, especially in case of large or massive tears. To enhance @entity79 , an injectable hydrogel made with periosteal progenitor cells(PPCs) and @entity7028 ( @entity7028 ) tethered with bone morphogenic protein-2( @entity9040 ) was developed to encourage extracellular matrix synthesis for tendon-to-bone healing in rotator cuff repair. METHODS: The infraspinatus tendon was cut from the greater tuberosity and repaired through a transosseous tunnel with the injectable progenitor cell- @entity9040 hydrogel applied between the tendon-bone interface. The injectable hydrogel was prepared from 10% @entity7028 ( @entity7028 ) containing 0.05% of the photoinitiator. @entity9040 tethered with @entity968 ( @entity970 ) was blended to the hydrogel. @entity95 periosteal progenitor cells (PPCs) isolated from periosteum were mixed with hydrogel and injected on the tendon-bone interface. Ultraviolet radiation (365  nm) was applied for 60  s to photopolymerize the injection and solidify the hydrogel. The @entity95 were killed at 4 and 8  weeks. The morphological characteristics of the healing tendon-to-bone interface were evaluated by histological and immunohistochemical methods. The biomechanical test was done to determine healing attachment strength. RESULTS: At both the 4- and 8-week killing, histological analysis of the tendon-bone interface showed an increasing fibrocartilage and bone layer formed in the tendon-bone interface in @entity7028 group. At 4  weeks, fibrocartilage-like tissue was observed in a focal area. At 8  weeks, further matrix deposition occurred with fibrocartilage formation in the @entity79 , and bone formation appeared near host bone. Immunohistochemistry revealed the presence of aggrecan and type II collagen. Biomechanical testing revealed a higher maximum pull-out load at all time points with a statistically significant difference at 4 and 8  weeks postoperatively. CONCLUSION: @entity7028 hydrogel was approved as an adequate matrix for the encapsulation of cells and signal factor, and as an effective local delivery method to the tendon-bone interface through injection and photopolymerization. The PPCs- @entity9040 -hydrogel provides a powerful inductive ability between the tendon and the bone and enhances @entity79 through the neoformation of fibrocartilage.
