A pig kidney successfully worked for two months in the body of a patient from New York: this is a record for such a transplant

A pig kidney transplanted into a patient in New York functioned in the donor's body for a record 2 months. The historic experiment ended Wednesday when surgeons at NYU Langone Health removed a pig kidney and returned Maurice "Mo" Miller's donated body to his family, according to a report. NBC New York.

This was the longest period of functioning of a genetically modified pork kidney inside a person, even a deceased one. By pushing the boundaries of research involving deceased people, scientists have learned important lessons that they are preparing to share with the Food and Drug Administration - in the hope that pig kidneys will eventually be tested on living people.

“It's a combination of excitement and relief,” said Dr. Robert Montgomery, the transplant surgeon who led the experiment. “Two months is a long time to get a pork kidney in such good condition. This gives more confidence” for the next attempts.”

Montgomery, a heart transplant recipient himself, believes animal-to-human transplants are critical to solving the nation's organ shortage. There are more than 100 people on the national waiting list, most of whom need a kidney, and thousands of whom could die waiting.

Experiment

Attempts at so-called xenotransplantation failed for decades - the human immune system immediately destroyed foreign animal tissue. Attempts to transplant organs from pigs that have been genetically modified to make their organs more similar to humans.

Some short experiments on dead organisms avoided immediate immune attack, but did not shed light on the more common form of rejection that can take up to a month to develop. Last year, surgeons at the University of Maryland tried to save a dying man using a pig's heart, but he lived only two months as the organ failed for unknown reasons.

The US Food and Drug Administration (FDA) provided Montgomery's team with a list of questions about how pig organs actually work compared to human organs.

Montgomery decided that keeping Miller's body on a ventilator for two months to see how a pig's kidney worked would answer some of these questions.

Difficult test

“I'm so proud of you,” Miller's sister, Mary Miller-Duffy, said as she bid a tearful goodbye to her brother this week.

Miller lost consciousness and was pronounced dead because he was unable to donate his organs due to cancer. After painful deliberation, Miller-Duffy donated the body of a man from Newburgh, New York, for an experiment with pigs. She recently received a card from a stranger in California awaiting a kidney transplant, thanking her for helping advance much-needed research.

“It was a very difficult test,” Miller-Duffy said as she hugged Team Montgomery.

In July, just before Maurice's 58th birthday, surgeons replaced his own kidneys with one from a pig and the animal's thymus gland, a gland that trains immune cells. During the first month the kidney functioned without any signs of problems.

But soon doctors noted a slight decrease in the amount of urine excreted. A biopsy confirmed a subtle sign of incipient rejection, giving doctors a chance to determine whether it could be treated. As it turned out, when replacing the standard immunosuppressive drugs that patients use today, kidney function was restored.

“We've learned that this is actually doable,” said New York University transplant immunologist Massimo Mangiola.

The researchers tested other FDA questions, including seeing no differences in how pig kidneys responded to human hormones, released antibiotics or experienced drug-related side effects.

“It looks great, just like normal kidneys look,” Dr. Jeffrey Stern said Wednesday, after removing the pig kidney at 61 days for closer examination.

Next Steps

The researchers took about 180 different tissue samples - from all major organs, lymph nodes, and the digestive tract - to look for any hints of problems associated with xenotransplantation.

According to Karen Maschke, a research fellow at the Hastings Center who helps develop ethical and policy guidelines for clinical trials of xenografts, experiments on dead people cannot predict that organs will perform as well as on living people.

However, she says they can provide other valuable information. In particular, they will help identify the differences between pigs that have up to 10 genetic changes, which some research groups prefer, and those used by Montgomery, which had just one change - deleting a gene that triggers an immediate immune attack.

“We're doing this because there are a lot of people who unfortunately die without the opportunity to have a second chance at life,” says Mangiola, an immunologist. “And we have to do something about it.”