Auricular tissue engineering using osteogenic differentiation of adipose stem cells with small intestine submucosa

Background: Ear reconstruction remains a challenge for plastic surgeons. A tissue-engineering approach could provide another route for obtaining shape maintenance in neoauricular tissue. Methods: The authors designed a novel tissue-engineering auricular construct by culturing human adipose stem cells, which differentiated into osteocytes but not chondrocytes, in small intestine submucosa scaffolds. The authors evaluated cell growth potential and mechanical properties. An ear-shaped construct was created in vitro and then implanted in the backs of nude mice. The histology, cellularity, neovascularization, mechanical properties, and ear shape maintenance were investigated. Results: In vitro, human adipose stem cells could be successfully seeded in the small intestine submucosa and differentiated toward osteogenesis. The ear-shaped human adipose stem cell/small intestine submucosa construct could maintain its shape in vivo up to 1 year. Alizarin Red S staining confirmed osteogenic differentiation. CD31 stain showed prominent angiogenesis in the human adipose stem cell/small intestine submucosa construct at 6 months and persistence up to 1 year. h-MHC stain revealed the maintenance of cellularity at 6 months and persistence up to 1 year. The mechanical properties were similar to those of native ear cartilage. Conclusion: The authors' study found that the combination of human adipose stem cells and small intestine submucosa could provide a more durable ear-shaped construct in vivo. The mechanical properties, shape, and cellularity were maintained in the constructs for up to 12 months.