Fabrication and biological activity of polycaprolactone/phlorotannin endotracheal tube to prevent tracheal stenosis: An in vitro and in vivo study.

Prolonged endotracheal intubation is the most common cause of tracheal stenosis, which may lead to serious airway obstruction. Development of an endotracheal tube coated with biomaterials that exhibit anti-inflammatory or anti-fibrogenic effects may prevent tracheal stenosis. This study demonstrates that an endotracheal tube coated with phlorotannin, which is present in extracts of the brown alga Ecklonia cava, can prevent tracheal stenosis in a rabbit model. An in vitro study shows that phlorotannin inhibits proliferation of human tracheal fibroblasts treated with transforming growth factor β1. Phlorotannin-coated endotracheal tubes show steady release of phlorotannin for up to 7 days, and removal of the tube 1 week after insertion reveals a reduction in both fibrogenesis and thickening of tracheal submucosa. Western blot analysis of tracheal tissues after removal of the phlorotannin-coated tube shows decreased protein expression levels of phenotypic markers of fibrosis such as collagen type I and α-smooth muscle actin. The ability of phlorotannin-coated endotracheal tube to prevent tracheal stenosis caused by endotracheal intubation indicates that phlorotannin may be considered as a candidate biomaterial for coating the cuff of endotracheal tubes to prevent tracheal stenosis.