Tissue engineered stents created from chondrocytes

Purpose: Trauma, operations or instrumentation of the urethra or ureter may lead to stricture disease. The use of a natural urethral stent made of aut ologous tissue would be advantageous due to its biocompatibility. In this s tudy we investigated the feasibility of engineering cartilage stents in vit ro and in vivo. Materials and Methods: We fabricated 40 cylinders 10 mm. long with an inner and outer diameter of 5 and 9 mm., respectively, from polyglycolic acid me sh coated with 50:50 polylactic-co-glycolic acid. Chondrocytes isolated fro m bovine shoulders were seeded onto the tubular polymer scaffolds at a seed ing density of 60 x 10(6) cells per mi. Scanning electron microscopy was pe rformed to determine the even distribution of chondrocytes throughout the p olymer scaffolds. We implanted 20 cylinders under the skin of nude mice and 20 were cultured in stirred bio-reactors. Cytological characteristics, col lagen content and mechanical durability were evaluated 4 and 10 weeks after cell seeding. Results: Gross examination of the engineered stents showed the solid, glist ening appearance of cartilaginous tissue. Cytological analyses with hematox ylin and eosin, trichrome, alcian blue and safranin O confirmed cartilage, and the deposition of collagen and glycosaminoglycan in each group. Increas ed deposition of collagen and glycosaminoglycan was observed in the stents created in vivo. Biomechanical testing demonstrated that the cartilaginous cylinders in each group were readily elastic and withstood high degrees of pressure. Conclusions: This study demonstrates the feasibility of creating cartilagin ous stents in vitro and in vivo using chondrocyte seeded polymer matrices. This technology may be useful clinically for stricture disease in the genit ourinary tract.