In this episode of The Story Behind the AP Story, we hear from Lauran Neergaard and Shelby Lum, who have been following the journey of animal to human transplants, or xenotransplants, over the last few years.

Maryland doctors say the second person to receive a transplanted heart from a pig has died.

The second person to receive a transplanted heart from a pig has reached the one-month mark and a hospital video shows he's working hard to recover.

Surgeons have transplanted a pig’s heart into a dying man in a bid to prolong his life.