Nail zone stem cells, tissue regrow fingertips

Stem cells under the base of a fingernail could one day be used to treat malformed nails or possibly amputated limbs, research by New York University suggests. A study in mice indicated a chemical signal that triggers stem cells to develop into new nail tissue also attracts new nerves that promote nail and bone regeneration, ScienceNews.com reported Wednesday. Mayumi Ito of New York University Langone Medical Center and her colleagues found stem cells that produce the hard nail and the soft tissue underneath. When they cut off the end of a mouse's toe, signals from the regrowing nail stimulated the tissue below to form new bone, the authors said. Researchers said they found the digit bones can regenerate only if the stump has some nail stem cells remaining. However, they also found that cells alone weren't enough -- also necessary was an area of tissue that grows from the stem cells during normal nail growth, ScienceNews.com said. After amputation, the tissue sends signals that attract nerves into the end of the stump and begin bone regeneration, researchers said. If the nail zone is removed or the signals are blocked, regeneration won't occur. When the researchers genetically manipulated the mice to initiate the regeneration signals permanently, nail stem cells alone spurred regeneration even without the nail tissue zone, ScienceNews.com said. The findings were published in Wednesday's edition of Nature.