OVERLAND PARK, Kan. (AP) – A 12-year-old yellow Labrador retriever named Jake is recovering as his family waits to see if a stem cell injection will regenerate his limbs and help him roam again without pain.

Jake underwent surgery Tuesday at the Stanley Veterinary Clinic in Overland Park, where fat was removed from his body then injected into his joints.

“It’s amazing,” said veterinarian Les Pelfrey, who conducted the procedure. “A few weeks later, these guys are running up and down.”

Supporters say the procedure will give Jake a better quality of life. Critics contend the procedure has not been proven to have any long-term benefits and is expensive, at $1,800 or more per treatment