IndiGlobal Media Bureau
Fifty-seven year-old human created history with the recent transplant of genetically modified Pig’s heart in Baltimore, City of Maryland. He is still in Intensive Care Unit and slowly being moved out of ECMO treatment. His medical readings in Intensive Care Unit in recovery state are encouraging.
Dr Amaresh Rao Malempati unit head of Department of Cardio-Thoracic Surgery at Nizam’s Institute of Medical Sciences, Hyderabad details on whether the use of animal organs or tissues is the way ahead or are we doing enough to preserve and protect what we have!
First permitted and genetically modified Pig’s Heart:
Fifty-seven-year-old David Bennett was transplanted genetically modified Pig’s heart on January 7 th , 2022. Surgery was performed by Dr Bartley Griffith in the presence of the Chair of the Department of Surgery, Dr Christine Lau, at the University of Maryland Medical Center, Baltimore.
The transplant is a technical success.
But how long will the patient survive with Pig’s heart – only time will tell.
History of David Bennett’s Heart Failure:
- Bed-ridden and on life-support system for 6 weeks
- Unfit for Human Heart Transplant
Why Pig’s Heart?
- Pig’s Heart was provided by Genetic Company, REvivocor after special permissions to carry out the procedure.
- This transplant was not a clinical trial.
- The Pig underwent 10 Genetic alternations and David received an experimental drug to prevent the body from rejecting the heart.
- Pigs organs have been earlier transplanted in baboons and also brain dead human cadavers as a part of research.
- These research results have been studied for long and were used in this genetic modification from Pig to Human.
Will this address Organ Shortage?
The step is heralded as a medical breakthrough and a step towards reducing the global shortage of organs for end stage failure. However, this is not the first-time animal hearts or organs were transplanted into humans. Xenotransplantation, the process of transplantation of animal tissues into humans, has held the fascination of the medical fraternity since long, given the shortage of human organs. From sheep blood transfusions in the 17 th century, to animal skin for burn patients, baboon hearts, kidneys and livers have all often been tried. The use of pig’s hearts came about when the gibbon’s hearts usage was not successful. Gibbon’s hearts were used since they are genetically closest to man. Yet they were rejected as their sizes were too small.
Pigs, on the other hand, had hearts which were more or less similar to the humans, and were much easier to breed and manage. In fact, the pig heart valves are used to make artificial valves which are used to replace the diseased valves in the humans and are hugely successful.
Pig heart transplant was done in India too, when Dr Dhani Ram Baruah, an Assamese Cardiac Surgeon, along with a Hong Kong based surgeon Dr Jonathan Ho Kei-Shing, transplanted a pigs heart into a terminally ill human patient Purno Saikia in January 1997 at his “Heart City”, at Sonapur, 20 kms from Guwahati. The patient survived for 7 days, however, Dr Dhani Ram was arrested as the required permissions for the procedure under the Transplantation act were not procured. He was subsequently released on bail after 40 days, but his hospital was destroyed by the mob.
There are, however, many challenges in transplanting the Pigs heart into humans. The Pigs tissues contain certain molecules, which are immediately recognized as foreign, and quickly attacked and rejected by the immune system of the recipient. The rejection of the body is in several ways, and is both sudden or over a period of time. Hence numerous scientific adjustments are made to get over this problem.
Using various genetic modification techniques, the substances causing these rejections are either eliminated or hidden in the pig’s tissues. Similarly the tissues are modified in such a way that the bodies fighting mechanism has no effect on these tissues. Experiments have been done to try and make the host learn the tissues as their own. Several medications have been developed, which either suppresses or modifies the body’s response to the foreign tissues. Some of them have found acceptance in clinical use, many remain experimental.
The pig whose heart was used for the transplant, was genetically modified. As many as 10 genetic alterations were done to the pig to make it human friendly. It was separated immediately after birth and raised in a sterile environment to keep it free from various diseases.
Challenges in transplanting a Pig’s heart to Humans:
- Pigs transmit life-threatening viral infections.
- Viral elements are embedded in the genetic system of Pig and it requires special treatment.
- Pig is a four-legged animal and its heart is not designed to supply blood to upright two-legged humans.
- Cultural barriers against pigs especially amongst Muslims and Jews and also animal activists vehemently oppose using animal organs for human-beings.
With so much demand and the challenges, what is the road ahead? The future is a multi-horse race, with several exciting newer technologies on the horizon. Newer technologies like genetic engineering, stem cell research, total artificial heart, newer medications to modify immunity, chimeras in the form of human organs made to grow in the embryos of pigs and other animals, 3D printing of organs and several such technologies are all heating up the race.
While we celebrate each step taken towards advancement of science and pushing the frontier of medicine, let us not forget to strive to preserve what is already given to us, and treat our bodies with the utmost care and respect.
