HEART XENOGRATIFICATION: A big step towards pig heart transplantation

Six months ago, the team performed this genetically modified pig heart transplant in a 57-year-old patient with end-stage heart disease and during a unique surgical procedure. Surgery was then the only available treatment option for the patient who was ineligible for a conventional heart transplant and was suffering from heart failure. The US Food and Drug Administration (FDA) has approved the process for compassionate use.

Heart xenograft could save lives?

Prior to transplantation, the patient had been bedridden for 8 weeks and had received extracorporeal membrane oxygenation (ECMO) to stay alive. A few days after the transplant, the ECMO was removed and the patient gradually began active rehabilitation for almost two months. The doctors then describe considerable progress, his heart strengthens, “the patient shows a great will to live”, specifies one of the main authors, Dr. Bartley Griffith, Professor Emeritus of Surgery.

So the transplanted pig heart worked well several weeks and showed none of the typical signs of rejection even at the autopsy. Therefore, the researchers conclude that the patient died of heart failure, which was probably caused by a number of complex factors. The team is therefore very confident about the safety and effectiveness of the procedure, including the genetically modified pig heart and the experimental drug used to prevent rejection.

“Xenografts could save many lives”,

adds, one of the lead authors, Dr. Muhammad M. Mohiuddin, Professor of Surgery and Director of the Cardiac Xenotransplantation Program.

“Our autopsy results show no evidence of rejection. We see thickening and then stiffening of the heart muscle, resulting in diastolic heart failure, meaning the heart muscle was unable to relax and fill the heart with blood.”

Several possible factors: The researchers identify several possible causes of death:

  • the use of intravenous immunoglobulin, IVIG, a drug given twice to the patient in the second month after the transplant to prevent rejection and infection. The medicine contains antibodies against pig cells that may have interacted with the pig’s heart, causing a reaction that can damage the heart muscle;
  • The heart was also found to contain DNA traces of a latent porcine virus called porcine cytomegalovirus (pCMV), although there was no evidence of infection in the patient. Before the operation, measures to prevent infection were carried out. The healthy donor pig used for xenotransplantation had been subjected to multiple pathogen tests.

“We were pioneers with this world first and have learned a lot from this experience. We have entered a new era of organ transplantation. While we still have a long way to go before xenotransplantation becomes a daily reality, this landmark surgery brings within our reach a future many never thought possible.”

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