Kangaroos are among the

and Makana Therapeutics are engineering pigs to be more humanlike.So far in the U.S. there have been four “compassionate use” transplants, last-ditch experiments into dying patients — two hearts and two kidneys. Revivicor provided both hearts and one of the kidneys. While the four patients died within a few months, they offered valuable lessons for researchers ready to try again in people who aren’t quite as sick.

Now the FDA is evaluating promising results from experiments in donated human bodies and awaiting results of additional studies of pig organs in baboons before deciding next steps.They’re semi-custom organs — “we’re growing these pigs to the size of the recipient,” Ayares noted — that won’t show the wear-and-tear of aging or chronic disease like most organs donated by people.Transplant surgeons who’ve retrieved organs on Revivicor’s farm “go, ‘Oh my god that’s the most beautiful kidney I’ve ever seen,’” Ayares added. “Same thing when they get the heart, a pink healthy happy heart from a young animal.”

PIgs stand in pens at the Revivicor research farm near Blacksburg, Va., on May 29, 2024, where organs are retrieved for animal-to-human transplant experiments. (AP Photo/Shelby Lum)PIgs stand in pens at the Revivicor research farm near Blacksburg, Va., on May 29, 2024, where organs are retrieved for animal-to-human transplant experiments. (AP Photo/Shelby Lum)

The main challenges: how to avoid rejection and whether the animals might carry some unknown

The process starts with modifying genes in pig skin cells in a lab. Revivicor initially deleted a gene that produces a sugar named, which tries to predict disease trends.

The center, created during the COVID-19 pandemic, was working on forecasting the current multi-state measles outbreak. That forecast hasn’t been published partly because of the layoffs, according to two CDC officials who spoke on condition of anonymity because they are not authorized to discuss it and fear retribution for speaking to the press.Trump hasn’t always supported widespread testing of health problems.

In the spring of 2020, when COVID-19 diagnoses were exploding, the president groused that the nation’s ability to do more testing was making the U.S. look like it had a worse problem than other countries. He called testing “a double-edged sword.”Mooney, the Johns Hopkins historian, wonders how interested the new administration is in reporting on health problems.