Transplanting body parts of other animals to human is called xenotransplantation.
Xenotransplantation is hard because our immune system produce antibodies against these transplant which makes it incompatible in few days.
These antibodies are mediated against special sugar present in the heart cells which are antigenic.
Surgeon transplanted pig heart to human for first time in Jan 7. For Details on this breakthrough surgery , click here
Why pig heart ?
You may be wondering why pig is used for transplantation instead of monkey, baboon or chimpanzees. The reason is simple.
Surgeon chose pig heart for transplant because they are similar in size to our human heart.
Which Gene Editing were done ?
Gene are basically recipe in our DNA for proteins. If these genes are removed , the body cannot produce the protein which recipe is encoded in the gene.
A key problem in xenotransplantation is antibodies produced by human recognize certain sugars on the surface of pig cells as foreign.
“You really need to get rid of as much antibody binding as you can upfront to get the graft to survive longer,” says Joseph Tector, a transplant surgeon at the University of Miami who was not involved with the new surgery.
The pig underwent total of 10 gene editing to reduce the immune response which makes the transplanted organ survive for longer time.
So, in one of its lines of engineered pigs, Revivicor deleted three genes for enzymes that enable pig cells to synthesize those sugars.
Six human genes were added :
a. two anti-inflammatory genes,
b. two genes that promote normal blood coagulation and prevent blood vessel damage
c. two other regulatory proteins that help tamp down antibody response.
A final genetic modification removed the gene for a growth hormone receptor to reduce the chance that a pig organ will grow larger in size.
So total of 10 gene editing were done: 3 gene deletion to reduce antigenic sugar, addition of 6 human genes and removal of growth hormone receptor gene.
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Sachet Subedi is 3rd year medical student from Institute Of Medicine, Maharajgunj . He writes on health, diet, wellness and science. He likes cricket and loves to study books and research paper on productivity, diet , health and wellness.