Production of very large sized scaffold-free engineered cartilage constructs from the adult equine donor - A basis for therapeutic and experimental applications in the horse

Abstract

The horse being a model of high interest for cartilage repair studies, the feasibility of engineering scaffold-free cartilage constructs of very large size was studied for to prepare further pre-clinical testing of such constructs in vivo. The engineering of large scaffold-free cartilage constructs from chondrocytes of adult equine donors should be demonstrated. An in vitro study was carried out with chondrocytes from adult equine donors, which had to be euthanised for reasons unrelated to the locomotor system. Cartilage biopsies were taken post mortem under surgical conditions. After digestion (pronase/collagenase), scaffold-free tissue engineered cartilage was produced from the resulting chondrocytes (p0). Furthermore, chondrocytes were propagated in monolayer culture, and cartilage constructs produced from passages 1 and 2 (p1, p2). Cartilage formation was allowed for at least 6 weeks and up to 6 months. Histologic and biochemical analyses of the constructs were performed to characterise the resulting constructs. Engineered cartilage constructs up to 6 cm2 large could be produced from adult equine chondrocytes that were propagated in vitro over zero to two passages. The engineered equine cartilage appeared soft after the initial 4 weeks, but matured conceivably with time to form a dense and firm cartilage like tissue. The technology used to produce autologous, scaffold-free, engineered cartilage constructs might be applied for adult horses, but also other species including man, to generate autologous cartilage implants to cover large cartilage defects. The horse may be a good animal model to study the treatment of large cartilage defects by implantation of autologous tissue engineered cartilage constructs.