I came across this news a few times in the last couple of days. Maybe not quite limb regeneration, or in humans at the moment, but it’s still just amazing.
From the link:
To figure out why mammalian muscle cells can’t regenerate, Blau’s team looked for proteins known to block cell division, focusing specifically on those that are found in mammals and birds but not in amphibians capable of regeneration. They identified one candidate, called ARF. Blocking both this protein and a similar protein, Rb, identified in previous research, enabled cells isolated from mouse muscle to begin dividing. When transplanted back into mice, the engineered cells integrated with existing muscle fibers, but only if Rb was turned back on. The scientists haven’t yet shown that this muscle works properly.
Researchers ultimately hope to develop ways to regenerate tissue damaged via injury or disease. The ability to precisely re-grow cells in the pancreas or the heart, for example, could provide new therapies for diabetes or heart disease. The team now plans to examine whether the same approach will work in these types of cells.