Biocompatibility and Immunophenotypic Characterization of a Porcine Cholecyst-derived Scaffold Implanted in Rats.

Comparative histomorphological assessment of local response to implanted reference biomaterial, also called biocompatibility testing/evaluation, in an appropriate animal model is a widely practiced safety evaluation procedure performed on biomaterials before clinical use. Standardized protocols and procedures, originally designed for testing synthetic materials, available for the testing/evaluation do not account for the immunogenic potential of a candidate biomaterial. Therefore, it is appropriate to supplement the routine biocompatibility test reports with adjunct data that may provide insight into the immunogenic potential of candidate biomaterials, especially when testing biomaterials that are derived from mammalian sources. This article presents expanded safety evaluation data of a porcine cholecyst-derived scaffold (CDS) intended as a xenogeneic graft. The biocompatibility was tested in rat subcutaneous model in comparison with a reference material and the CDS was found biocompatible. However, when studied by immunohistochemistry and real-time reverse transcription polymerase chain reaction for the number and/or polarization of M1 macrophage, M2 macrophage, cytotoxic T-cell, helper T cell, TH1 cell, and TH2 cell, the CDS appeared to induce a differential local immunopathological tissue reaction despite the similarity in biocompatibility with the reference material. The adjunct data collected were useful for objectively assessing the safety of CDS as a xenograft.