内容摘要：Jennie Joseph, lead midwife and clinic director at the Commonsense Childbirth clinic talks with clients and staff. The midwives who run the program welcome vulnerable patients that other practices turn away, such as those who are uninsured or haven’t had prenatal care until late in pregnancy. (AP Photo/John Raoux)

Jennie Joseph, lead midwife and clinic director at the Commonsense Childbirth clinic talks with clients and staff. The midwives who run the program welcome vulnerable patients that other practices turn away, such as those who are uninsured or haven’t had prenatal care until late in pregnancy. (AP Photo/John Raoux)

, which triggers immediate destruction from the human immune system. Next came three-gene “knockouts,” to remove other immune-triggering red flags. Now the company is focusing on 10 gene edits — deleted pig genes and added human ones that together lessen risk of rejection and blood clots plus limit organ size.They clone pigs with those alterations, similar to how Dolly the sheep was created.

Twice a week, slaughterhouses ship Revivicor hundreds of eggs retrieved from sow ovaries. Working in the dark with the light-sensitive eggs, scientists peer through a microscope while suctioning out the maternal DNA. Then they slip in the genetic modifications.A worker at United Therapeutics’ designated pathogen-free facility in Christiansburg, Va., on May 29, 2024 retrives a UV sterilized item from behind a protected barrier within the facility. (AP Photo/Shelby Lum)A worker at United Therapeutics’ designated pathogen-free facility in Christiansburg, Va., on May 29, 2024 retrives a UV sterilized item from behind a protected barrier within the facility. (AP Photo/Shelby Lum)

“Tuck it in nice and smooth,” murmurs senior researcher Lori Sorrells, pushing to just the right spot without rupturing the egg. Mild electric shocks fuse in the new DNA and activate embryo growth.Ayares, a molecular geneticist who heads Revivicor and helped create the world’s first cloned pigs in 2000, says the technique is “like playing two video games at the same time,” holding the egg in place with one hand and manipulating it with the other. The company’s first modified pig, the

single gene knockout, now is bred instead of cloned. If xenotransplantation eventually works, other pigs with the desired gene combinations would be, too.

Hours later, embryos are carried to the research farm in a handheld incubator and implanted into waiting sows.But “we’re not off the hook yet,” cautioned Dr. Nader Moazami, the NYU cardiac surgeon who implanted the heart pump.

“With this surgery I get to see my wife smile again,” Pisano’s husband Todd said Wednesday.Other transplant experts are closely watching how the patient fares.

“I have to congratulate them,” said Dr. Tatsuo Kawai of Mass General, who noted that his own pig kidney patient was healthier overall going into his operation than NYU’s patient. “When the heart function is bad, it’s really difficult to do a kidney transplant.”More than 100,000 people are on the U.S. transplant waiting list, most who need a kidney, and thousands die waiting. In hopes of filling the shortage of donated organs, several biotech companies are genetically modifying pigs so their organs are more humanlike, less likely to be destroyed by people’s immune system.