The Scaffold Derived from GGTA1 and CMAH Gene Knockout Pigs Generated by Gene Editing Provoked Little Inflammatory Responses in a Humanized Pig Model

Abstract BackgroundThe porcine small intestinal submucosa ECM (SIS-ECM) has been used as a supportive scaffold for healing in a variety of tissues. However, the outcomes of its application are far from satisfactory.ResultsThe possibility of generating a porcine small intestinal submucosa extracellular matrix (SIS-ECM) that is fully biocompatible was investigated. Samples of SIS-ECM were prepared from either domestic wild-type (WT) or double-gene knockout (dKO) pigs without antigenic responses to α-Gal and N-glycolylneuraminic acid (Neu5Gc). The scaffolds, which were sutured into cuts made in the longissimus muscle of the dKO pigs, were expected to exhibit xeno-reactions through natural antibodies as in a human response. A process was established to manufacture ameliorating acellular porcine SIS-ECM implants with consistent quality characteristics, which were assured by analyzing the level of residual DNA, the glycosaminoglycan content, and histochemical stains. Once implanted, the acellular SIS-ECM from the WT pigs caused a significant increase in serum IL-6 levels in the dKO recipient pigs, indicating a host defense through immune reactions. The levels remained unchanged when preparations from the dKO pigs were used. The pathological score of the multinuclear giant cells of the dKO (WT) group (2.3±0.5) was significantly greater than that of the dKO (dKO) group (0.7±0.3).ConclusionThe IL-6 levels and pathological evidences suggested that dKO pigs without α-Gal or Neu5Gc antigenic causing lower inflammatory response can serve as biocompatible SIS-ECM donors or as animal models for testing anthropomorphic immune responses to biomedical devices.