Inducing articular cartilage phenotype in costochondral cells

Area of Science:

• Tissue Engineering
• Cartilage Regeneration
• Biomaterials Science

Background:

• Costochondral cells offer a viable cell source for articular cartilage regeneration due to minimal donor site morbidity and resistance to joint pathologies.
• Identifying optimal exogenous stimuli is crucial for generating abundant, hyaline articular cartilage from costochondral cells.

Purpose of the Study:

• To investigate the effects of hydrostatic pressure (HP), transforming growth factor β1 (TGF-β1), and chondroitinase ABC (C-ABC) on costochondral cell redifferentiation.
• To assess the capability of these stimuli, individually and in combination, to produce hyaline articular cartilage with functional mechanical properties.

Main Methods:

• A three-factor, two-level full factorial design was employed to test HP, TGF-β1, and C-ABC on third-passage expanded, redifferentiated costochondral cells.
• Cartilage matrix content, superficial zone protein (SZP) expression, and mechanical properties were evaluated after 4 weeks of culture.

Main Results:

• Hyaline articular cartilage was successfully generated, confirmed by the presence of type II collagen and SZP, and absence of type I collagen.
• TGF-β1 significantly increased collagen and glycosaminoglycan synthesis, enhancing tensile and compressive moduli. C-ABC boosted collagen content and mechanical strength.
• Combined TGF-β1 and C-ABC treatments showed synergistic effects, significantly increasing collagen content and tensile strength, outperforming individual treatments and HP.

Conclusions:

• Biochemical, biophysical, and mechanical stimuli effectively produced robust hyaline articular cartilage with significant tensile (2 MPa) and compressive (650 kPa) moduli.
• The use of expanded, redifferentiated costochondral cells in a self-assembling process successfully recapitulated mechanical properties and induced SZP expression, characteristic of functional articular cartilage.