Harvard scientists have discovered a new and potentially safer cell-reprogramming pathway that could bypass the controversial ethical issues generated by embryonic stem cell research.

Harvard Medical School professor Damian D. Medici developed a new method for reprogramming mature endothelial cells—which line the interior of blood vessels—into adult stem cells that can then be stimulated to become a variety of different mature cell types.

Medici’s study, published online earlier this week in the journal Nature Medicine, found a mutated gene that causes a disease known as Fibrodysplasia Ossificans Progressiva induced endothelial cells to become cells very similar to adult mesenchymal stem cells, which have the ability to differentiate into bone, fat, and cartilage cells.

FOP is an extremely rare genetic disease in which the patient’s soft tissue gradually hardens into cartilage and bone.

In addition, Medici said the new discovery is “a much safer alternative than induced pluripotent stem cells,” which also come from reprogrammed mature cells but can lead to cancer in patients.

When researching FOP, Medici and his colleagues found the mutated cells contained biomarkers for endothelial cells, perhaps indicating that FOP cells had an endothelial origin.

When Medici introduced FOP into normal endothelial cells, he found the cells had transformed into what was very close to adult stem cells.

Medici and his colleagues also found two growth factors, TGF-beta2 and BMP4, that mimicked the effects of the FOP gene and led to the transformation of mature cells into adult stem cells.

According to Medici, future studies will focus on how to treat FOP patients, and searching to find out whether the reprogramming mechanism found in FOP might be present in other diseases as well.