Human heart muscle cells can be created in the lab, but researchers have been unable to grow the immature cells to the point where they could be useful.
It's a conundrum that's stumped researchers in regenerative medicine.
"You cannot really use them for regeneration. You cannot even use them for disease models," said Chulan Kwon, a professor at the Johns Hopkins School of Medicine.
But Kwon said he's discovered a solution for the problem in an unlikely place — newborn rats — and he published a study about his research last month in the journal Cell Reports.
When immature human heart cells are injected into baby rats, they match the rodents' rapid growth...