Integration of engineered cartilage

Abstract

The structure and function of cartilaginous constructs, engineered in vitro using bovine articular chondrocytes, biodegradable scaffolds and bioreactors, can be modulated by the conditions and duration of tissue cultivation. We hypothesized that the integrative properties of engineered cartilage depend on developmental stage of the construct and the extracellular matrix content of adjacent cartilage, and that some aspects of integration can be studied under controlled in vitro conditions. Disc-shaped constructs (cultured for 5 i 1 days or 5 * 1 weeks) or explants (untreated or trypsin treated cartilage) were sutured into ring-shaped explants (untreated or trypsin treated cartilage) to form composites that were cultured for an additional 1-8 weeks in bioreactors and evaluated biochemically, histologically and mechanically (compressive stiffness of the central disk, adhesive strength of the integration interface). Immature constructs had poorer mechanical properties but integrated better than either more mature constructs or cartilage explants. Integration of immature constructs involved cell proliferation and the progressive formation of cartilaginous tissue, in contrast to the integration of more mature constructs or native cartilage which involved only the secretion of extracellular matrix components. Integration patterns correlated with the adhesive strength of the disc-ring interface, which was markedly higher for immature constructs than for either more mature constructs or cartilage explants. Trypsin treatment of the adjacent cartilage further enhanced the integration of immature constructs.

Cartilage tissue engineering by expanded goat articular chondrocytes

“…37 On the other hand, less developed engineered cartilage could integrate more efficiently with native cartilage, due to higher accessibility of cells at the interface. 38 Taken together, these findings indicate the need to identify an appropriate degree of tissue development that guarantees at the same time cell protection, appropriate response to loading, as well as integrative capacity. In this context, the feasibility demonstrated here to engineer goat cartilaginous tissues at different stages of development by varying culture time is propaedeutic at studying the effect of engineered cartilage maturation on the outcome of cartilage repair in an orthotopic goat model.…”

Cartilage tissue engineering for degenerative joint disease☆

“…Compared to fibrin, collagen, Poly(L-lactic acid) (PLLA), and poly (DL-lactic-co-glycolic acid) (PLGA), PGA was shown to provide a better scaffold for in vitro cartilage regeneration, as demonstrated by cell densities equivalent to those found in natural tissues, and by continuous cellular production of type II collagen [174]. Although such engineered constructs have also been tested for articular cartilage repair in animal models, mainly in rabbits [94,171,[175][176][177]), they have not been applied in human patients.…”

Combination of baculovirus-expressed BMP-2 and rotating-shaft bioreactor culture synergistically enhances cartilage formation

“…33 The ex vivo approach minimizes the unwanted immune responses but the cell/scaffold constructs devoid of cartilage ECM may have suboptimal mechanical properties to tolerate the mechanical loading in vivo immediately after implantation, which could impair subsequent tissue integration. 34 In addition, the cells transplanted into full-thickness defects may not remain for long time periods. 35 In contrast to repair approaches based on formation and maturation of new tissue in situ, the generation of cartilaginous tissues may be achieved by implanting a preformed graft.…”