Translational Development of a Silk-Elastinlike Protein Polymer Embolic for Transcatheter Arterial Embolization

Locally blocking blood flow to tumors with embolic materials is the key to transcatheter arterial embolization for treating hepatocellular carcinoma. Current microparticle agents do not deeply penetrate target tissues and are compatible with a very limited selection of therapeutic agents. Silk-elastinlike protein polymers (SELPs) combine the solubility of elastin and the strength of silk to create an easily injected liquid embolic that transition into a solid depot amenable to loading with drugs, gene therapy agents, or biologics. SELP, injected as liquid solution, penetrates the vasculature before transitioning to a solid hydrogel. The objective of this manuscript is to evaluate SELP embolization, stability, and biocompatibility at 7-, 30-, and 90-day survival intervals in a porcine model. SELP embolics selectively block blood flow in the kidneys and livers, with no off-target infarctions. As assessed with angiography, SELP renal embolization exhibits decreasing persistence for the duration of the 90-day study period. There is an increased presence of microscopic SELP emboli in the renal setting, compared to Embosphere. Histologically scored inflammatory reactions to SELP are decreased in both the renal and hepatic implantations compared to Embosphere. In conclusion, a bioresorbable SELP liquid embolic system deeply penetrates target tissue and selectively embolizes blood vessels in vivo.