In Vitro and Pilot In Vivo Evaluation of a Bioactive Coating for Stent Grafts Based on Chondroitin Sulfate and Epidermal Growth Factor

Purpose: To evaluate the potential of a bioactive coating based on chondroitin sulfate (CS) and tethered epidermal growth factor (EGF) for improvement of healing around stent grafts (SGs). Materials and Methods: The impact of the bioactive coating on cell survival was tested in vitro on human vascular cells using polyethylene terephthalate films (PET) as a substrate. After being transferred onto a more realistic material (expanded polytetrafluoroethylene [ePTFE]), the durability and mechanical behavior of the coating and cell survival were studied. Preliminary in vivo testing was performed in a canine iliac aneurysm model reproducing type I endoleaks (three animals with one control and one bioactive SG for each). Results: CS and EGF coatings significantly increased survival of human smooth muscle cells and fibroblasts compared with bare PET or ePTFE (P < .05). The coating also displayed good durability over 30 days according to enzyme-linked immunosorbent assay and cell survival tests. The coating did not affect mechanical properties of ePTFE and was successfully transferred onto commercial SGs for in vivo testing. No difference was observed on computed tomography and macroscopic examinations in endoleak persistence at 3 months, but the bioactive coating deposited on the abluminal surface of the SG (exposed to the vessel wall) increased the percentage of healed tissue in the aneurysm. No adverse effect, such as neointima formation or thrombosis, was observed. Conclusions: The bioactive coating promoted in vitro cell survival, displayed good durability, and was successfully transferred onto a commercial SG. Preliminary in vivo results suggest improved healing around bioactive SGs.