NEW YORK (StudyFinds.org) — With organ donors always in short supply, an ongoing study has identified a possible alternative — animal organs.

Researchers from New York University Langone Health say they have successfully completed a xenotransplantation, meaning taking an organ from one species and implanting it into another, not once, but twice. A team of surgeons used a genetically engineered pig kidney, transplanting it into a human body without suffering from rejection.

Dr. Robert Montgomery notes that both transplant recipients were actually deceased, with their bodies being kept alive using a ventilator. Nevertheless, the two surgeries proved that a specially designed kidney from another species could help provide life-saving organs to those in desperate need.

“We have been able to replicate the results from the first transformative procedure to demonstrate the continued promise that these genetically engineered organs could be a renewable source of organs to the many people around the world awaiting a life-saving gift,” says Montgomery in a university release. “There is much more work to do before we begin living human trials, but our preliminary findings give us hope.”

How did scientists avoid organ rejection?

Before the two transplants, performed on Sept. 25 and Nov. 22, scientists genetically modified the pig kidney to lack the alpha-gal gene, which triggers the antibody-led rejection of pig organs by humans. Scientists also fused the pig’s thymus gland to the kidney before transplantation. The gland “teaches” the immune system how to make white blood cells and fight off infections.

Montgomery and the team attached the kidney to the human body’s upper leg, near the abdomen. Over the next 54 hours, they monitored urine production and creatinine levels from the kidney. These are important markers that show if a kidney is functioning properly — whether it’s from a person or pig. Results show the kidney’s functioning matched what doctors would expect from a normal human kidney transplant. Doctors also report that there were no signs of rejection following the procedures.

“We continue to make progress with the single-gene knockout xenotransplantation,” Montgomery adds. “With additional study and replication, this could be the path forward to saving many thousands of lives each year.”

Family sacrifice may lead to hope for thousands

Researchers note that the two bodies were donated by LiveOnNY, a nonprofit organization that facilitates organ and tissue donation in the New York area, on behalf of families who agreed to allow scientists to use their loved one’s whole body for scientific research.

According to the United Network for Organ Sharing, over 90,000 people across the United States are currently waiting for a life-saving kidney transplant.

“This is a transformative moment in organ transplantation,” Montgomery said in an earlier release. “The medical and scientific communities have been working toward xenotransplantation to sustain human life for more than 50 years. There have been many hurdles along the way, but our most recent procedure significantly moves these endeavors forward. This research provides new hope for an unlimited supply of organs, a potential game-changer for the field of transplantation and those now dying for want of an organ.”