US researchers test pig-to-human transplant in donated body

U.S. researchers are reporting the latest in a surprising string of experiments in the quest to save human lives with organs from genetically modified pigs

Via AP news wire
Thursday 20 January 2022 12:00
Pig Transplants
Pig Transplants

Researchers on Thursday reported the latest in a surprising string of experiments in the quest to save human lives with organs from genetically modified pigs.

This time around, surgeons in Alabama transplanted a pig’s kidneys into a brain-dead man — a step-by-step rehearsal for an operation they hope to try in living patients possibly later this year.

“The organ shortage is in fact an unmitigated crisis and we’ve never had a real solution to it,” said Dr. Jayme Locke of the University of Alabama at Birmingham, who led the newest study and aims to begin a clinical trial of pig kidney transplants.

Similar experiments have made headlines in recent months as research into animal-to-human transplants heats up.

Twice this fall, surgeons at New York University temporarily attached a pig’s kidney to blood vessels outside the body of a deceased recipient to watch them work. And earlier this month, surgeons at the University of Maryland Medical Center gave a dying man a heart from a gene-edited pig that so far is keeping him alive.

But scientists still needed to learn more about how to test such transplants without risking a patient’s life. With the help of a family who donated a loved one's body for science, Locke mimicked the way human organ transplants are done — from removing the pig “donor” kidneys to sewing them inside the deceased man's abdomen.

For a little over three days, until the man's body was removed from life support, the pair of pig kidneys survived with no sign of immediate rejection, her team reported Thursday in the American Journal of Transplantation.

That was only one of several key findings. Locke said it wasn't clear if delicate pig kidney blood vessels could withstand the pounding force of human blood pressure -- but they did. One kidney was damaged during removal from the pig and didn’t work properly but the other rapidly started producing urine as a kidney should. No pig viruses were transmitted to the recipient, and no pig cells were found in his bloodstream.

But Locke said the kidney experiment could have more far-reaching impact -- because it shows that a brain-dead body can be a much-needed human model to test potential new medical treatments.

The research was conducted in September after Jim Parsons a 57-year-old Alabama man, was declared brain-dead from a dirt bike racing accident.

After hearing this kind of research "had the potential to save hundreds of thousands of lives, we knew without a doubt that that was something that Jim would have definitely put his seal of approval on,” said Julie O’Hara, Parsons’ ex-wife.

The need for another source of organs is huge: While more than 41,000 transplants were performed in the U.S. last year, a record, more than 100,000 people remain on the national waiting list. Thousands die every year before getting an organ and thousands more never even get added to the list, considered too much of a long shot.

Animal-to-human transplants, what’s called xenotransplantation, have been attempted without success for decades. People’s immune systems almost instantly attack the foreign tissue. But scientists now have new techniques to edit pig genes so their organs are more human-like — and some are anxious to try again.

The recent string of pig experiments “is a big step forward,” said Dr. David Kaczorowski of the University of Pittsburgh Medical Center. Moving on to first-stage trials in potentially dozens of people is “becoming more and more feasible.”

A heart transplant surgeon, Kaczorowski has done experiments testing pig organs in non-human primates that helped pave the way but “there are only things we can learn by transplanting them into humans.”

Hurdles remain before formal testing in people begins, including deciding who would qualify to test a pig organ, said Karen Maschke, a research scholar at the Hastings Center who will help develop ethics and policy recommendations for the first clinical trials under a grant from the National Institutes of Health.

Scientists also still have much to learn about how long pig organs survive and how best to genetically alter them, cautioned Dr. Robert Montgomery of NYU Langone Health, who led that center's kidney experiments in the fall.

“I think different organs will require different genetic modifications,” he said in an email.

For the newest kidney experiment, UAB teamed with Revivicor, the subsidiary of United Therapeutics that also provided organs for the recent heart transplant in Maryland and the kidney experiment in New York. Company scientists made 10 genetic changes to these pigs, knocking out some genes that trigger a human immune attack and make the animals’ organs grow too large — and adding some human genes so the organs look less foreign to people’s immune systems.

Then there are practical questions such as how to minimize time spent getting pig organs to their destination. UAB housed the altered pigs in a germ-free facility in Birmingham complete with an operating room-like space to remove the organs and ready them for transplant.

Revivicor chief scientific officer David Ayares said future plans include building more such facilities near transplant centers.

___

The Associated Press Health & Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.

Register for free to continue reading

Registration is a free and easy way to support our truly independent journalism

By registering, you will also enjoy limited access to Premium articles, exclusive newsletters, commenting, and virtual events with our leading journalists

Please enter a valid email
Please enter a valid email
Must be at least 6 characters, include an upper and lower case character and a number
Must be at least 6 characters, include an upper and lower case character and a number
Must be at least 6 characters, include an upper and lower case character and a number
Please enter your first name
Special characters aren’t allowed
Please enter a name between 1 and 40 characters
Please enter your last name
Special characters aren’t allowed
Please enter a name between 1 and 40 characters
You must be over 18 years old to register
You must be over 18 years old to register
Opt-out-policy
You can opt-out at any time by signing in to your account to manage your preferences. Each email has a link to unsubscribe.

By clicking ‘Create my account’ you confirm that your data has been entered correctly and you have read and agree to our Terms of use, Cookie policy and Privacy notice.

This site is protected by reCAPTCHA and the Google Privacy policy and Terms of service apply.

Already have an account? sign in

By clicking ‘Register’ you confirm that your data has been entered correctly and you have read and agree to our Terms of use, Cookie policy and Privacy notice.

This site is protected by reCAPTCHA and the Google Privacy policy and Terms of service apply.

Register for free to continue reading

Registration is a free and easy way to support our truly independent journalism

By registering, you will also enjoy limited access to Premium articles, exclusive newsletters, commenting, and virtual events with our leading journalists

Already have an account? sign in

By clicking ‘Register’ you confirm that your data has been entered correctly and you have read and agree to our Terms of use, Cookie policy and Privacy notice.

This site is protected by reCAPTCHA and the Google Privacy policy and Terms of service apply.

Thank you for registering

Please refresh the page or navigate to another page on the site to be automatically logged inPlease refresh your browser to be logged in