Xenotransplantation - A Medical Breakthrough
- On January 10, the University of Maryland School of Medicine announced that it had successfully transplanted a genetically-modified pig heart into a patient with life-threatening arrhythmia, a disorder that affects the rate or rhythm of heartbeats.
- The patient, David Bennett (57), was deemed ineligible for a conventional heart transplant or an artificial heart by leading transplant centers after a review of his medical records.
- In January, 1964, Dr. James Hardy and his team at the University of Mississippi transplanted a chimpanzee’s heart into a 68-year-old man.
- The first cardiac transplant into a human was a xenotransplant, and it failed within hours.
A Medical Breakthrough
- It is the first genetically-engineered porcine heart transplanted into a 57-year-old patient at the University of Maryland on January 7, 2022 by Dr. Bartley Griffith and his surgical team.
- The patient is currently awake, breathing on his own, and successfully weaned off of mechanical circulatory support.
- Xenotransplantation(heterologous transplant) is the process of the transplantation of living cells, tissues or organs from one species to another. Such cells, tissues or organs are called xenografts or xenotransplants.
- Arrhythmia - Rate or rhythm of the heartbeat are too quick, too slow, or with an irregular pattern.
Need for Xenotransplantation
- According to the health ministry, around 0.18 million people in India suffers kidney failures every year(only 6,000 transplants).
- 25,000-30,000 liver transplants are needed every year in India(only 1,500 are being performed).
- 50,000 - heart failure(only 10-15 heart transplants).
- Kidney, liver and heart transplants from non-human primates to humans happened in the 1970s. failed due to rejection.
- In 1984, a human infant received a heart from a baboon. The experiment failed when the baby died after 21 days.
- In September 2021, surgeons at the New York University Langone Health medical center transplanted a kidney of a genetically modified person into a brain-dead person.
- The second such pig kidney experiment was carried out in November, 2021 on a person in a ventilator(The process of genetic modification to protect from rejection).
- In India as well, Dhaniram Baruah, a cardio-thoracic surgeon based in Sonapur near Guwahati, transplanted the organs of a pig into a human body in 1997(It failed).
- The human immune system rejects anything foreign, scientists tweaked the pig genome is less likely to be rejected.
- A small herd of genetically engineered pigs is being raised.
- 10 pigs - Their genes genetically modified to reduce the possibility of rejection.
- 4 are inactivated, 6 human genes were inserted to further reduce the risk of rejection.
- In the 1990s, all human immune reactions were centered against one pig antigen i.e. a sugar molecule present on cell surfaces.
- DNA of pigs also contains retroviruses that can infect human cells.
- Many retroviruses have been removed from the organ to make it safer when transplanted.
- Genome-editing tools such as CRISPR/Cas9, made gene modification simpler, fast and accurate.
- This is an experimental surgery and brings with huge risks for the patient.
- Even well-matched human donor organs can be rejected after they are transplanted and with animal organs, the danger is likely to be higher.
- Chances Of Infection - High Community Risk
- Use of pigs for human transplants, which many animal rights groups oppose.
- People for the Ethical Treatment of Animals (PETA) has condemned the experiment as ""unethical, dangerous, and a tremendous waste of resources"".
- Another dilemma emerges around the acceptance of animal organs based on their religious faiths
- Rich and Poor Differentiation