First human recipient of pig kidney transplant dies

Sub: Science and tech

Sec: health

Context:

The first recipient of a modified pig kidney transplant passed away on May 11, around two months after the surgery was carried out.

What is Xenotransplantation?

Xenotransplantation, or heterologous transplant, is the transplantation of living cells, tissues or organs from one species to another.
Such cells, tissues or organs are called xenografts or xenotransplants.
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
Xenotransplantation involving the heart was first tried in humans in the 1980s.
At present, various large animals have been used in xenotransplantation, including pigs, monkeys, chimpanzees and baboons.
Pigs are considered the most ideal organ xenograft donor because their organ size, physiological metabolism and immune system are similar to those of human beings.
The need for such a procedure was felt because of the significant gap between the number of transplantations needed by patients and the availability of donor organs.
HMS surgeons at Brigham and Women’s Hospital performed the first successful human organ transplant of a kidney in 1954.

Why are pigs often used for xenotransplantation?

The pig’s anatomical and physiological parameters are similar to that of humans, and the breeding of pigs in farms is widespread and cost-effective.
Many varieties of pig breeds are farmed, which provides an opportunity for the size of the harvested organs to be matched with the specific needs of the human recipient.
In January 2022, the first xenotransplantation of a genetically-modified pig heart was done.

What Methodology is employed in Xenotransplantation?

The first step involved genetically modifying the pig organs to be more compatible with humans.
The kidney used in the new surgery was modified using the gene-editing technology CRISPR-Cas9 to:
- Remove certain pig genes that produce sugars with antibodies our immune systems react to.
- Add certain human genes to improve the kidney’s compatibility with humans.
- Inactivate viruses present in all pig genomes, known as porcine endogenous retroviruses, in the donor pig to eliminate risk of infection in the recipient.

What are the complications in xenotransplantation?

It has to be ensured that the body does not reject the organ.
One method of doing this is embedding the pig’s thymus gland, responsible for educating the immune system, underneath the outer layer of the kidney.
This helps keep away any new or delayed immune responses.

What is Crispr-CAS9?

CRISPR-Cas9 is a genome editing tool that is creating a buzz in the science world.
It is faster, cheaper and more accurate than previous techniques of editing DNA and has a wide range of potential applications.
CRISPR-Cas9 is a unique technology that enables geneticists and medical researchers to edit parts of the genome by removing, adding or altering sections of the DNA sequence.
It is currently the simplest, most versatile and precise method of genetic manipulation and is therefore causing a buzz in the science world.