Editors' ChoiceTissue Engineering

Caution: Cartilage under reconstruction

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Science Translational Medicine  03 Oct 2018:
Vol. 10, Issue 461, eaav3881
DOI: 10.1126/scitranslmed.aav3881


A bioactive 3D-printed scaffold combined with microfracture surgery promotes cartilage tissue regeneration.

Approximately 14 million people in the United States are affected by knee osteoarthritis (OA). Current treatments include surgically drilling small holes in the bone underlying the affected region to promote cellular healing processes (microfracture) or cell transplant to the affected region (autologous chondrocyte implantation, ACI). However, microfracture results in comparatively weaker tissue relative to native cartilage, and ACI requires multiple surgeries, is costly, and has challenges in cultivating the necessary cell population size. Guo and colleagues established a cost- and labor-effective approach using microfracture surgery to improve therapeutic outcomes.

Guo et al. developed a three-dimensional (3D)–printed polymer scaffold functionalized with aggrecan, the main proteoglycan component of native articular cartilage. By combining the bioactive scaffold with a microfracture surgical procedure, they demonstrated an improvement in the quality of regenerated cartilage tissue in a rabbit knee defect model, where the functionalized scaffold resulted in more homogenous thickness in regenerated cartilage compared with defect controls and microfracture surgery alone. Clinically, cartilage thickness is an important factor for determining progression of OA. The bioactive scaffolds showed better integration with the newly regenerated tissue which was attributed to the biological activity provided by aggrecan: Aggrecan likely preserved the cell and growth factors released from bone marrow during microfracture treatment. Bioactive scaffolds resulted in 4.4 times more glycosaminoglycan (GAG) production compared with microfracture treatment, a positive indication of cartilage tissue regeneration as GAGs are a major component of native cartilage.

The typical variance in success of microfracture surgical intervention, which the authors attribute to lack of guidance and support for cells and biomolecules in the defect area, can be reduced by incorporating the 3D bioactive scaffold at the defect site. This therapeutic innovation offers great potential in the treatment of large cartilage defects in a cost-effective manner without requiring additional surgeries. Although further research is warranted in larger animals and adhesion improvements in scaffold fixation are recommended, this study could promise a further clinical solution to improve the quality of repaired cartilage tissue.

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