Summary in seconds: the first genetically modified pig heart transplant to a Maryland man resulted in earlier success followed by fatal heart swelling a setback not a decisive failure. Unraveling Xenotransplantation’s promise amid urgent demand for human spare parts.
On the chilly morning of Friday, January 7th of last year*, 57-year-old David Bennett Sr. stood on the brink of a life-changing moment. In the University of Maryland Medical Center, a dedicated team of cardiac surgeons prepared for a groundbreaking experiment—a second chance for Bennett with the first-ever transplantation of a genetically modified pig organ into a human capable of survival and recovery.
Mr. Bennett’s medical team disclosed that he battled heart failure, an irregular heartbeat, and a past record of noncompliance with medical instructions. Due to these factors, he was considered unsuitable for a human heart transplant, which necessitates strict adherence to immune-suppressing medications, or the alternative option—an implanted heart pump.
In 2021, at New York University Langone Health, a significant medical milestone was achieved when surgeons transplanted kidneys from the same lineage of genetically modified pigs into two legally deceased individuals with no detectable brain function. Remarkably, the procedure proved successful, as the transplanted organs remained unrejected and functioned seamlessly, sustaining the recipients on ventilators.
The January 7th operation held high hopes for researchers to reignite clinical xenotransplantation and navigate through numerous ethical and regulatory challenges. Advancements in xenotransplantation have been notable in recent years, particularly with the integration of CRISPR-Cas9 genome editing, facilitating the creation of pig organs less prone to immune system rejection in humans.
On January 10, just three days after the groundbreaking surgery, the University of Maryland Medical Center delivered positive news about Mr. Bennett’s progress. However, in the following days, Dr. Bartley Griffith, the surgeon who conducted the transplant, noticed signs of infection emerging in Mr. Bennett. Despite administering a combination of antibiotics, antiviral medication, and immune-boosting treatments, Bennett’s pig heart began to swell, accumulating fluid and eventually ceasing to function. Tragically, on March 8, two months after the operation, David Bennett Sr. passed away. Subsequently, his medical team discovered viral DNA within the pig heart but could not definitively link this virus, identified as porcine cytomegalovirus, to Mr. Bennett’s infection.
For decades, medical professionals have attempted to utilize animal organs to save human lives, with little success. Facing a dire situation and deemed ineligible for a human heart transplant, Mr. Bennett underwent a last-minute procedure utilizing a genetically modified pig heart to mitigate the risk of rapid rejection by his immune system.
Researchers delving into the cause of death of the first individual to receive a pig heart transplant made a significant revelation – the transplanted organ contained an animal virus. Nonetheless, they were unable to ascertain the precise role this virus played in Mr. Bennett’s demise. Subsequently, more advanced tests are currently under development to ensure the detection of such viruses in the future, preventing any oversight.
Meanwhile, medical centers across the country have been conducting their own experiments with animal organs in human recipients, eagerly anticipating formal studies in living patients. However, the potential impact of the pig virus on these plans remains uncertain.
Sources
1. “Pig heart transplanted into Maryland man was carrying an animal virus”
CBS NEWS, First published on May 5, 2022 / 8:25 PM
2. Why was David Bennett ineligible for a heart transplant?
3. First pig-to-human heart transplant: what can scientists learn?
By Sara Reardon
Nature, 14 January 2022
https://www.nature.com/articles/d41586-022-00111-9
4. What are genome editing and CRISR-Case9?
Medline, Last updated March 22, 2022
https://medlineplus.gov/genetics/understanding/genomicresearch/genomeediting/
5. Xenotransplantation: is any procedure that involves the transplantation, implantation or infusion into a human recipient of either: (a) live cells, tissues, or organs from a nonhuman animal source, or (b) human body fluids, cells, tissues or organs that have had ex vivo contact with live nonhuman animal cells, tissues or organs.
* This article was previously posted on June, 2022 in my earlier blog “My Islam”. The article has been slightly modified to fit its current posting date.