Implant-type tissue-engineered cartilage derived from human auricular chondrocyte may maintain cartilaginous property even under osteoinductive condition

Abstract

Introduction: There is a growing need for chondrocyte implantation for reconstructing cartilage defect. However, ossification of the implanted cartilage is a challenging problem. Implant-type tissue-engineered cartilage from human auricular chondrocytes is a three-dimensional implant type cartilage using PLLA as a scaffold for chondrocytes. Although there is a study which evaluated the ossification of this cartilage in subcutaneous area, there is no study which clarify the possibility of ossification in osteoinductive surroundings. The purpose of this study was to elucidate the possibility of the ossification of implant-type tissue-engineered cartilage using human auricular chondrocyte in an osteoinductive environment. Methods: Human chondrocytes were harvested from ear cartilage. After dispersion by enzyme digestion, they were put into either a poly-L-lactic acid (PLLA) or poly lactic-co-glycolic acid (PLGA) scaffold, with collagen gel. Implant-type tissue-engineered cartilage was interposed between pieces of human iliac bone harvested from the same donor and implanted subcutaneously in nude rats. Scaffold without chondrocytes was used as a control. After 1, 3, and 6 months, ossification and cartilage formation were evaluated by X-ray, hematoxylin-eosin (HE) stain and toluidine blue (TB) stain. Results: There was no ossification of implant-type cartilage using human chondrocytes, even under osteoinductive conditions. HE staining showed that perichondrium formed around the constructs and chondrocytes were observed 6months after the implantation. TB staining showed metachromasia in every sample, with the area of metachromasia increasing over time, suggesting maturation of the cartilage. Conclusions: In conclusion, adjacent iliac bone had no apparent effect on the maturation of cartilage in implant-type tissue-engineered cartilage. Cartilage retention and maturation even in the presence of iliac bone could have been due to a scarcity of mesenchymal stem cells in the bone and surrounding area.

Experimental Study on the Biological Outcome of Auricular Cartilage and Costal Cartilage at Different Time Periods After Autologous Cartilage Rhinoplasty

“…21 Both auricular and costal cartilages use chondrocytes generated under the perichondrial membrane for replacement and updates. 22 As the immature cells gradually mature, they secrete a large amount of matrix, wrapping themselves and growing into the cartilage center, where the homologous cells show clustered or bead-like aggregated distribution. The cell volume also gradually increases, turning from a flat to a quasi-circular shape.…”

“…The histologic component of auricular cartilage is elastic cartilage, which plays an important role in maintaining the shape of the auricle 21. Both auricular and costal cartilages use chondrocytes generated under the perichondrial membrane for replacement and updates 22. As the immature cells gradually mature, they secrete a large amount of matrix, wrapping themselves and growing into the cartilage center, where the homologous cells show clustered or bead-like aggregated distribution.…”