Xenotransplantation

Single-nucleus transcriptome sequencing reveals hepatic cell atlas in pigs

BACKGROUND

As the largest substantive organ of animals, the liver plays an essential role in the physiological processes of digestive metabolism and immune defense. However, the cellular composition of the pig liver remains poorly understood. This investigation used single-nucleus RNA sequencing technology to identify cell types from liver tissues of pigs, providing a theoretical basis for further investigating liver cell types in pigs.

RESULTS

The analysis revealed 13 cells clusters which were further identified 7 cell types including endothelial cells, T cells, hepatocytes, Kupffer cells, stellate cells, B cells, and cholangiocytes. The dominant cell types were endothelial cells, T cells and hepatocytes in the liver tissue of Dahe pigs and Dahe black pigs, which accounts for about 85.76% and 82.74%, respectively. The number of endothelial cells was higher in the liver tissue of Dahe pigs compared to Dahe black pigs, while the opposite tendency was observed for T cells. Moreover, functional enrichment analysis demonstrated that the differentially expressed genes in pig hepatic endothelial cells were significantly enriched in the protein processing in endoplasmic reticulum, MAPK signaling pathway, and FoxO signaling pathway. Functional enrichment analysis demonstrated that the differentially expressed genes in pig hepatic T cells were significantly enriched in the thyroid hormone signaling pathway, B cell receptor signaling pathway, and focal adhesion. Functional enrichment analysis demonstrated that the differentially expressed genes in pig hepatic hepatocytes were significantly enriched in the metabolic pathways.

CONCLUSIONS

In summary, this study provides a comprehensive cell atlas of porcine hepatic tissue. The number, gene expression level and functional characteristics of each cell type in pig liver tissue varied between breeds.

Evolution of Xenotransplantation as an Alternative to Shortage of Donors in Heart Transplantation

This review aims to show and illustrate the history, current, ethical considerations, and limitations concerning xenotransplantation. Due to the current shortage of available donor organs for transplantation, many alternative sources are being examined to solve the donor shortage. One of them is xenotransplantation which refers to the transplantation of organs from one species to another. Compared to other nonhuman primates (NHP), pigs are ideal species for organ harvesting as they rapidly grow to human size in a handful of months. There is much advancement in the genetic engineering of pigs, which have hearts structurally and functionally similar to the human heart. The role of genetic engineering is to overcome the immune barriers in xenotransplantation and can be used in hyperacute rejection and T cell-mediated rejection. It is technically difficult to use large animal models for orthotopic, life-sustaining heart transplantation. Despite the fact that some religious traditions, such as Jewish and Muslim, prohibit the ingestion of pork products, few religious leaders consider that donating porcine organs is ethical because it saves human life. Although recent technologies have lowered the risk of a xenograft producing a novel virus that causes an epidemic, the risk still exists. It has major implications for the informed consent procedure connected with clinical research on heart xenotransplantation.

Emerging technologies in organ preservation, tissue engineering and regenerative medicine: a blessing or curse for transplantation?

Since the beginning of transplant medicine in the 1950s, advances in surgical technique and immunosuppressive therapy have created the success story of modern organ transplantation. However, today more than ever, we are facing a huge discrepancy between organ supply and demand, limiting the potential for transplantation to save and improve the lives of millions. To address the current limitations and shortcomings, a variety of emerging new technologies focusing on either maximizing the availability of organs or on generating new organs and organ sources hold great potential to eventully overcoming these hurdles. These advances are mainly in the field of regenerative medicine and tissue engineering. This review gives an overview of this emerging field and its multiple sub-disciplines and highlights recent advances and existing limitations for widespread clinical application and potential impact on the future of transplantation.