How genetically modified pigs could end the shortage of organs for transplants

David Ayares, president and chief scientific officer of Revivicor, holds a piglet raised for research at a company farm in Montgomery County, Virginia. (Scott P. Yates for NPR)

NEAR BLACKSBURG, Va. — It's a crisp, clear winter day as I drive down a winding two-lane road through the foothills of the Blue Ridge Mountains in southwest Virginia and turn onto an unmarked gravel driveway.

At the end of the drive, I meet David Ayares, who runs Revivicor Inc., a biotech company based in Blacksburg, Virginia.