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Abstract: TH-OR77

Evaluation of Porcine Cell Chimerism and Viral Transmission Using a Preclinical Human Brain-Dead Decedent Model

Session Information

Category: Transplantation

  • 2101 Transplantation: Basic

Authors

  • Cheung, Matthew David, The University of Alabama at Birmingham Heersink School of Medicine, Birmingham, Alabama, United States
  • Fucile, Christopher, The University of Alabama at Birmingham Heersink School of Medicine, Birmingham, Alabama, United States
  • Asiimwe, Rebecca, The University of Alabama at Birmingham Heersink School of Medicine, Birmingham, Alabama, United States
  • George, James F., The University of Alabama at Birmingham Heersink School of Medicine, Birmingham, Alabama, United States
  • Locke, Jayme E., The University of Alabama at Birmingham Heersink School of Medicine, Birmingham, Alabama, United States
  • Porrett, Paige Marie, The University of Alabama at Birmingham Heersink School of Medicine, Birmingham, Alabama, United States
Background

Xenotransplantation is a potential solution to the organ shortage crisis, but questions around the potential for zoonotic disease transmission need to be addressed before clinical trials can be safely undertaken. Because zoonotic transmission cannot be assessed in vitro or in preclinical animal models, we used a preclinical brain-dead human decedent model to evaluate porcine cell chimerism in human tissues as well as the transmission of porcine endogenous retroviruses (PERVs) and porcine cytomegalovirus (PCMV) after porcine kidney xenotransplantation.

Methods

Kidneys were procured from a 10-gene modified pig, transplanted into two nephrectomized brain-dead human decedents, and followed for 3 days. Single-cell RNA seq (scRNAseq) was performed on peripheral blood mononuclear cells (PBMCs) sorted from the xenograft recipients before and after transplantation on post-operative (POD) days 1, 2, and 3. Single-nucleus RNA seq (snRNAseq) was performed on kidney biopsies collected pre-transplant and on POD 1 and 3, as well as distant tissues such as heart, lung, liver, spleen, lymph node, small bowel, and omentum upon termination of the experiment. Sequencing data were aligned to a novel PERV-PCMV-porcine-human merged reference genome to differentiate porcine and human cell types and assess for viral transcript expression. Data were analyzed using the package Seurat 4.0.

Results

ScRNAseq analysis of over 500,000 PBMCs revealed a small number of porcine cells (0.04% and 0.008%) in decedent 1 and 2, respectively, while there was no detection of porcine cells in any of the 150,000 sequenced cells from human organs. PERV-A and PERV-B (expression level range: 0.5-4) transcripts were detected in a small number of porcine kidney cells (0.79%) and within the porcine cells detectable in the human PBMCs; however, there was no detection of PERV-C. There was no detection of PERV in any of the human organs. No PCMV was detectable in any porcine or human compartment.

Conclusion

Sc- and snRNAseq can detect viral transcript expression and cell chimerism from mixed porcine-human samples. There was no detectable PERV or PCMV transmission early after xenotransplantation, but limited by the short duration of the study. Additional studies will be needed to address long-term safety profiles after xenotransplantation.

Funding

  • Commercial Support – United Therapeutics Corporation