Assessment of growth factor treatment on fibrochondrocyte and chondrocyte co-cultures for TMJ fibrocartilage engineering

Abstract

Treatments for patients suffering from severe temporomandibular joint (TMJ) dysfunction are limited, motivating the development of strategies for tissue regeneration. In this study, co-cultures of fibrochondrocytes (FC) and articular chondrocytes (AC) were seeded in agarose wells, and supplemented with growth factors, to engineer tissue with biomechanical properties and ECM composition similar to native TMJ fibrocartilage. In the first phase, growth factors were applied alone and in combination, in the presence or absence of serum, while in the second phase, the best overall treatment was applied at intermittent dosing. Continuous treatment of AC/FC co-cultures with TGF-β1 in serum-free medium resulted in constructs with GAG/WW (12.2%), instantaneous compressive moduli (790 kPa), relaxed compressive moduli (120 kPa), and Young's moduli (1.87 MPa) that overlap with native TMJ disc values. Among co-culture groups, TGF-β1 treatment increased collagen deposition ~20%, compressive stiffness ~130%, and Young's modulus ~170% relative to no growth factor controls. Serum supplementation, though generally detrimental to functional properties, was identified as a powerful mediator of FC construct morphology. Finally, both intermittent and continuous TGF-β1 treatment showed positive effects, though continuous treatment resulted in greater enhancement of construct functional properties. This work proposes a strategy for regeneration of TMJ fibrocartilage and its future application will be realized through translation of these findings to clinically viable cell sources.

Autologous adipose stem cells and polylactide discs in the replacement of the rabbit temporomandibular joint disc

“…This is also demonstrated in fibrochondrogenic ECM formation in TMJ disc engineering [35]. Recently, different co-cultures of stem cells and mature fibrochondrogenic cells have been suggested to have potential route for the production of fibrocartilaginous tissue in vitro [45,48].…”

“…TGF-b1 is a traditional differentiation factor used in chondrogenic cultures [81] and is also advantageous in fibrochondrogenic cultures of mature TMJ disc-derived fibrochondrocytes [39,45] as well as ASCs aiming at TMJ disc reconstruction [40]. There were some donor-dependent differences between autologous ASC disc implants at the time of implantation.…”

“…The disadvantage of autologous cartilage is its limited availability owing to donor site scarcity and morbidity. These factors have increased interest towards the use of stem cells for the TMJ disc replacement [44,45,47,48]. Adipose tissue is an expendable, and abundant source of autologous adult stem cells capable of undergoing differentiation towards cells of mesenchymal origin, including the fibroblasts and chondrocytes found in the TMJ disc [40,49,50].…”

“…This is achieved in an appropriate stimulatory environment in a three-dimensional culture system created with biodegradable scaffolds [42,51] or by cell self-assembly in a scaffold-free approach [43,45,52]. Ideally, the tissue-engineered TMJ disc would provide a structurally and functionally analogous equivalent to the native TMJ disc.…”

“…Moreover, TMJ disc-derived fibrochondrocytes tend to change their phenotype during expansion in the laboratory [10,37,40,44]. Alternatively, chondrocytes from other cartilage types [36,37,45,46] or dermal fibroblasts [43] have been examined for TMJ disc engineering. The disadvantage of autologous cartilage is its limited availability owing to donor site scarcity and morbidity.…”