Tissue-engineered versus native cartilage: linkage between cellular mechano-transduction and biomechanical properties

Recent studies demonstrate that chondrocytes in native articular cartilage and in tissue-engineered constructs respond to mechanical stimuli through multiple regulatory pathways. Responses of the cells are manifested by intra- and intercellular signalling, alterations in transcription level, protein translation, post-translational modifications, and synthesis of intracellular and extracellular macromolecules. In addition, mechanical stimuli can alter the balance between anabolic and catabolic processes that are critically important to cell-mediated extracellular assembly and degradation of the tissue matrix and, therefore, to the survival of tissue engineered constructs. Chondrocyte mechanotransduction is therefore a critically important link to the biomechanical properties of native cartilage and to developing constructs. Since implanted cartilage repair tissue will be subjected to mechanical loads throughout its lifetime, it is essential that the resident cells respond appropriately to the range of static and dynamic compressive and shear deformations in vivo in a manner that enables adaptive remodelling and minimizes catabolic degradation. The in vivo environment should thereby signal tissue-specific maturation and integration processes in order to achieve the most appropriate tissue morphology and biomechanical function.