The first successful human-to-human heart transplant was carried out 56 years ago. Since then, data has shown figures of 4000 to 5000 transplants each year. Heart transplantation has advanced significantly, and it is now regarded as a successful and exciting development in modern medicine. Recently, research on animal-to-human transplantation, also known as xenotransplantation, has been ongoing. The first ever porcine-to-human transplant was conducted by doctors at the University of Maryland medical center. The procedure involved a 54-year-old patient who had end-stage heart failure and wasn’t eligible for a human-to-human transplant. However, he died two months after the transplant was done successfully. A study has been ongoing by the transplant team to discover the reason for the failure.
Pig’s Heart Transplant. Image Courtesy of University of Maryland School of Medicine
Porcine heart failed due to the patient’s ill state
The study reveals that there were no symptoms of acute rejection in the first few weeks following the transplant. However, several overlapping factors could have led to heart failure. The team used the patient’s post-mortem tissues to carry out varying tests and investigations.
It was suggested that the patient’s generally poor health could have contributed to the failure of the procedure. His already immunocompromised state limited the team’s use of immunosuppressive medications, which subsequently led to the rejection of the pig’s organ. Antibodies were discovered during histological examination and single-cell RNA analysis.
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Another theory that was proposed blamed the use of intravenous immunoglobulin (IVIG), which may have caused myocardial damage. IVIG was administered on two occasions during the 2nd post-transplant month to prevent the occurrence of infection. This might have triggered adverse immune reactions. Also, the team discovered Ig antibodies on the inner wall of the blood vessels of the rejected organ.
Furthermore, a virus, porcine cytomegalovirus (PCMV), might have been implicated in the pathogenesis of this case. It is proposed that withdrawal of antiviral medications might have caused the virus to attack, although there is no concrete evidence for this.
Clinical significance
Organs from animals could be the future of transplant medicine. This study provides key lessons that could aid in future xenotransplants. Better immune-monitoring protocols that will aid the anti-rejection of xenotransplanted organs could be instituted to ensure a good outcome for patients.
Conclusion
Organ transplantation improves the quality of life of patients with end-stage organ failure. Due to advances in medical science, xenotransplantation could offer a groundbreaking solution for improving the quality of life.
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References
Mohiuddin, M. M., Singh, A. K., Scobie, L., Goerlich, C. E., Grazioli, A., Saharia, K., Crossan, C., Burke, A., Drachenberg, C., Oguz, C., Zhang, T., Lewis, B., Hershfeld, A., Sentz, F., Tatarov, I., Mudd, S., Braileanu, G., Rice, K., Paolini, J. F., Bondensgaard, K., Vaught, T., Kuravi, K., Sorrells, L., Dandro, A., Ayares, D., Lau, C., & Griffith, B. P. (2023). Graft dysfunction in compassionate use of genetically engineered pig-to-human cardiac xenotransplantation: a case report. The Lancet. https://doi.org/10.1016/S0140-6736(23)00775-4
