Crosslinking decreases the hemocompatibility of decellularized, porcine small intestinal submucosa.

Decellularized tissues have been widely used as scaffolds for biomedical applications due to their presentation of adhesion peptide sequences and growth factors, which facilitate integration with surrounding tissue. One of the most commonly used decellularized tissues is derived from porcine small intestinal submucosa (SIS). In some applications, SIS is crosslinked to modulate the mechanical properties or degradation rate of the scaffold. Despite the widespread use of SIS, there has been no mechanistic characterization of blood reactions with SIS, or how crosslinking affects these reactions. Therefore, we characterized the effect of SIS and carbodiimide-crosslinked SIS (cSIS) on plasma coagulation, including targeted assessments of the intrinsic and extrinsic coagulation pathways, and thrombus formation using flowing whole blood. SIS inhibited plasma coagulation initiated by recalcification, as well as low concentrations of thrombin or tissue factor. SIS prolonged the activated partial thromboplastin time by 14.3 ± 1.54s, indicating inhibition of the intrinsic coagulation pathway. Carbodiimide crosslinking abrogated all anticoagulant effects of SIS, as did heparinase I and III treatment, suggesting that heparin and heparan sulfate are predominantly responsible for SIS anticoagulant effects. Inhibiting contact activation of the intrinsic pathway prevented cSIS-mediated coagulation. When tubular SIS devices were connected to a nonhuman primate arteriovenous shunt loop, which enables whole blood to flow across devices without the use of anticoagulants, SIS demonstrated remarkably limited platelet accumulation and fibrinogen incorporation, while cSIS initiated significantly higher platelet and fibrinogen accumulation. These results demonstrate that SIS is a thromboresistant material and crosslinking markedly reduces the hemocompatibility of SIS.