Porcine Corneal Tissue and Xenozoonotic Risks: A Review of the Current Evidence

Corneal opacities affect millions worldwide, with corneal transplantation as the primary treatment. However, donor shortages remain a challenge, leaving thousands waiting for transplants. Xenotransplantation using porcine corneas has emerged as a promising alternative due to anatomical and physiological similarities with human corneas. Advances in CRISPR/Cas technology enable genetic modifications to address immune rejection and zoonotic risks. A key concern is xenozoonosis, the transmission of infectious agents from pigs to humans. Pathogens such as porcine endogenous retroviruses (PERVs), porcine cytomegalovirus (PCMV), and bacteria pose potential risks. While PERVs can infect human cells in vitro, no transmission has been documented in vivo. Regulatory bodies, including the WHO and IXA, have established guidelines for monitoring and clinical trials. The first human corneal xenotransplantation trials in South Korea and China are underway. Enhanced biosecurity measures in tissue banks have reduced microbial contamination, improving safety. Corneal xenotransplantation presents lower risks compared to solid organ xenotransplants. With ongoing research, stringent regulations, and improved pathogen-free animal models, this technique could become a viable clinical option. Future human trials will provide crucial insights into its long-term safety and effectiveness.