Efficacy evaluation of an in situ forming tissue adhesive hydrogel as sealant for lung and vascular injury

In situforming tissue adhesives based on biopolymers offer advantages over conventional sutures and staples in terms of biocompatibility, biodegradability, ease of application and improved patient compliance and comfort. Here, we describe the evaluation ofin situgelling hydrogel system based on dextran dialdehyde (DDA) obtained by periodate oxidization of dextran and chitosan hydrochloride (CH) as tissue adhesive. The hydrogel was prepared by reacting aldehyde functions in DDA with the amino functions in CH via Schiff's reaction. The gelation reaction was instantaneous and took just 4 s. The DDA-CH hydrogel as tissue adhesive was evaluated on a sheep lung parenchymal injury model and a pig aortic model and was compared with the commercially available tissue sealant, Bioglue®. The DDA-CH glue could completely seal the sheep lung incision site even at inflation with air way pressure of 30 cm of H2O with no air leak observed in the incision sites (n= 8) in any of the animals. Histological analyses showed mild inflammation after 2 weeks, comparable to Bioglue®. Resorption of test material by giant cells with no adverse effect on lung parenchyma was seen after 3 months. The DDA-CH glue was also very effective in sealing aortic incisions in a pig model (n= 4) with no failures and aneurisms. The endoluminal surface of the sealed incision in all cases showed intact apposition with adequate healing across the incision. No tissue necrosis or inflammation of endothelial surface could be seen grossly. Our studies show that the DDA-CH hydrogel could function as an effective sealant for the prevention of air and blood leaks following lung and vascular surgery.