In a scientific “first,” a tiny heart structure composed of human cells has been successfully grown within a pig embryo.

Scientists tracked how human immune cells attack pig kidneys after transplant—and found a way to fight back using precision therapies in the early rejection phase.

But there's a problem, and a big one at that: The body naturally wants to reject any tissue it knows it didn't manufacture.

In a first step toward FDA approval of kidney xenotransplantation, a living human with end-stage kidney disease may receive a ...