The hearts of mice contain a trove of adult stem cells. These resemble the mesenchymal stem cells found in bone marrow and other tissues, which can transform into bone, muscle or fat.

Richard Harvey at the Victor Chang Cardiac Research Institute in Darlinghurst, Australia, and his team isolated the cells in the hearts of adult and developing mice. The heart stem cells can divide repeatedly over long periods in culture, and bear surface proteins that resemble those found on other mesenchymal stem cells. Other experiments suggest that the heart stem cells develop from the same cells that form the heart during development. The study showed that the cells could develop into tissues including fat, cartilage and muscle.

It is unclear whether the stem cells naturally regenerate heart tissue, but they might provide a source of certain cell types for cardiac repair, the authors say.

Cell Stem Cell 9, 527–540 (2011)