For about six months, fully functioning grish hearts entered the chests of two Anubis baboons. Genetic modifications of the pig…
For about six months, fully functioning grish hearts entered the chests of two Anubis baboons. Genetic modifications of the pig heart along with a new transplant technique are credited with the longest but survival after such transplantation, researchers report on December 5th in Nature . Previously, the longest one lived after such a procedure for 57 days.
Another two baboons in the study lived for at least three months with the pig star and were in good health during that time, says Bruno Reichart, a cardiac surgeon at the Ludwig-Maximilians University University in Munich. The Bavians jumped and climbed around their envelopes. Some liked to eat mango and eggs and watch TV shows like “Tom and Jerry” and “Alvin and the Chipmunks”, he says.
This work causes researchers to approach the goal of successfully transplanting life-sustaining pigs to humans, “said Luhan Yang, Scientific Director of eGenesis, a Boston company that develops ways to transplant organs between different species to facilitate organ deficiency ( SN : 1
0/4/17, page 26 ). “Of course, it’s still early, but we’re one step closer to clinical application,” said Yang, who was not involved in the study.
The pigs were designed to produce a human version of two proteins – CD46, which blocks an immune response that pokes holes in foreign cells and thrombomodulin, preventing blood from coagulation after surgery. Researchers also assured that the pigs could not make alpha-gal sugar, which covers the cells of all mammals except monkeys, monkeys and humans. These sugars can test the immune system to attack organs transplanted from pigs to humans and other primates.
Researchers fine-tuned the transplant procedure during three trials involving 14 babies and found that two steps in the process were the key to its success. First, instead of transporting the organs in a cold solution – the usual practice of human-to-human transplants – the researchers linked hearts to a machine that constantly pumped an acid-blended mixture of blood and nutrients. Carrying the hearts of an ice bath can cut off oxygen to the organs. Repeated blood tests prevented the hearts from finally failing.
Thereafter, the researchers aimed at preventing the pig heart from growing too big for the baboons. After swelling from surgery, a transplanted heart continues to grow and may damage adjacent organs. Then, the researchers reduced the blood pressure of baboons and rejected the monkeys of anti-inflammatory cortisone steroids earlier. The team also gave the baboons a drug that limits the growth of the heart by keeping platelets from building up.
Of the five baboons in the last experiment, two healthy remained throughout the trial period of three months and one must be euthanized early after developing a blood clot. One of the two survived for six months eventually developed liver injury after refraining from medication while the other was relatively healthy.