Analysis of Human Auricular Cartilage to Guide Tissue-Engineered Nanofiber-Based Chondrogenesis: Implications for Microtia Reconstruction

Objective. Nanofiber-supported, in vitro-generated cartilage may represent an optimal starting material for the develop- ment of a cartilage implant for use in microtia reconstruc- tion. To do so, the authors aim to first characterize the molecular composition of endogenous auricular cartilage and determine if human umbilical cord mesenchymal stem cells (hUCMSCs) can be differentiated into cartilage in vitro. Study Design. Prospective, controlled. Setting. Academic research laboratory. Subjects and Methods. Human ear cartilage from normal adults, pediatric patients with microtia, and pediatric patients with pre- auricular appendages (n = 2) was analyzed for collagens I, II, and X and elastin expression. In parallel, hUCMSCs were cultured on either polycaprolactone (PCL) or D, L-lactide-co-glycolic acid (PLGA) nanofiber scaffolds for 21 days under chondrogenic con- ditions. Cells were harvested for histologic, biochemical, and quantitative polymerase chain reaction analysis. Control cells were grown under both chondrogenic and nonchondrogenic conditions in the absence of nanofiber scaffolds. Results. Histological analysis of human ear cartilage revealed similar levels and distribution of collagens I and X and elas- tin. Collagen II was not highly expressed in the microtia samples. hUCMSC cultures stained positively for glycosami- nosglycans (GAG) and sulfated proteoglycans. Compared to control cells, hUCMSCs grown on PLGA nanofiber scaffolds had a higher differentiation index (P.012) and higher levels of collagen X mRNA expression (P.006). Conclusion. These data provide information regarding the composition of endogenous ear cartilage and suggest that hUCMSCs grown on PLGA nanofiber scaffolds may repre- sent an optimal starting material for the development of a cartilage implant for use in microtia reconstruction.