Mitochondria Swap

Scientists have used two methods to generate patient-specific pluripotent stem cells with normal mitochondria for people with defects in these organelles, according to a study published today (July 15) in Nature. The first method generates stem cells for people with some normal mitochondria and some defective ones, a state called heteroplasmy. The researchers isolated fibroblasts from these patients and reprogrammed them to into multiple lines of induced pluripotent stem cells (iPSCs). They then tested these iPSC lines for mitochondrial mutations, selecting cells that had ended up with only nonmutated mitochondria following many cell divisions and mitochondrial redistributions. The second method, which works for patients who have no nonmutated mitochondria, involves transplanting these patients’ cell nuclei into healthy eggs with their own nuclei removed, a process called somatic cell nuclear transfer (SCNT).

“It’s a first step, but we will follow up with further research,” said study coauthor Shoukhrat Mitalipov, a professor at Oregon Health & Science University’s Center for Embryonic Cell and Gene Therapy in Portland. “Hopefully we will be going through some clinical trials using...