Human tracheal chondrocytes as a cell source for augmenting stenotic tracheal segments: the first feasibility study in an in vivo culture system

INTRODUCTION: Construction of engineered respiratory tract using tissue-engineered cartilage has not yet been reported. In order to generate artificial trachea using human chondrocytes obtained from tracheal cartilage, we investigated whether human tracheal chondrocytes can act as a cell source to fabricate engineered airway patches to augment stenotic parts of the trachea. MATERIALS AND METHODS: After informed consent, chondrocytes were obtained from five patients who needed tracheal surgery. A small piece of resected tracheal cartilage was digested by collagenase type 2 for 3-4 h. This yielded chondrocytes, which were expanded in vitro and seeded onto biodegradable scaffolds; these were then implanted subcutaneously in athymic mice. The implanted constructs were retrieved 8 weeks later for histologic and biochemical analysis. RESULTS: In monolayer cultures, chondrocytes proliferated well, showing a 100- to 1,000-fold increase in 1 month. Once expanded, the cells lost their original morphological and biologic characteristics, but the engrafted scaffold showed histologic and biochemical characteristics of cartilage. Viable chondrocytes and extracellular matrix were detected, and glycosaminoglycan (GAG) in vivo was present. CONCLUSIONS: Here we show that a small piece of human tracheal cartilage can generate sufficient chondrocytes in vitro and form tracheal cartilage architecture in an in vivo environment.