https://phys.org/news/2018-06-scientists-captured-elusive-cell-regenerate.html

"This is the first time that an adult pluripotent stem cell has been isolated prospectively," says Alejandro Sánchez Alvarado, Ph.D., an investigator at the Stowers Institute and Howard Hughes Medical Institute and senior author of the study. "Our finding essentially says that this is no longer an abstraction, that there truly is a cellular entity that can restore regenerative capacities to animals that have lost it and that such entity can now be purified alive and studied in detail."

Every multicellular organism is built from a single cell, which divides into two identical cells, then four, and so on. Each of these cells contains the exact same twisted strands of DNA, and is considered pluripotent—meaning it can give rise to all possible cell types in the body. But somewhere along the way, those starter cells—known as embryonic stem cells—resign themselves to a different fate and become skin cells, heart cells, muscle cells, or another cell type. In humans, no known pluripotent stem cells remain after birth. In planarians, they stick around into adulthood, where they become known as adult pluripotent stem cells or neoblasts. Scientists believe these neoblasts hold the secret to regeneration.