Tracheal repair with acellular human amniotic membrane in a rabbit model

Surgical correction of tracheal stenosis is still a complex and challenging procedure. Acellular human amniotic membranes (AHAM) represent a promising biomaterial source for tissue regeneration. The aim of this study was to evaluate whether AHAM grafts improve tissue regeneration of the trachea in a rabbit model of tracheostomy. Twenty rabbits were randomized into 2 groups. Animals in the control group underwent surgical tracheostomy only, and animals in the AHAM group underwent surgical tracheostomy and received an AHAM graft that covered the defect site. We examined tissues at the site of tracheostomy 60days after surgery by histological analysis with haematoxylin and eosin, Movat's pentachrome stain and immunohistochemistry by analysis with antiaggrecan antibodies. The average perimeter and area of the defect 60days after surgery were smaller in animals in the control group than in the AHAM group (p=.011 and p=.011, respectively). Histological analysis of AHAM group revealed neovascularization, islands of immature cartilage, pseudostratified ciliated epithelium. and connective tissue at the site of AHAM engraftment, whereas only pseudostratified ciliated epithelium and connective tissue were observed at the defect site in tissues of animals in the control group. Regeneration of islands of immature cartilage tissue with hyaline pattern and pseudostratified ciliated epithelium were confirmed by immunohistochemistry analysis. These results indicate that AHAM engraftment could facilitate neovascularization and regeneration of immature cartilage in a model of tracheal injury. Its use may lower the risk of post-operative complications including stenosis of trachea.