After apical tip resection, the heart from a two-day-old mouse (left) forms scars (white patches), while the heart from a one-day-old mouse (right) regenerates.MARIO NOTARI, CMRBNewborn mice are able to repair damaged heart tissue better than animals injured just a few days later in their lives. What accounts for this regenerative capacity, and exactly when and why it disappears, have been unanswered questions. A report in Science Advances today (May 2) posits that the extracellular matrix gets in the way of heart tissue renewal.
The investigators also found that scarring was minimal in mice injured on their first day of life, but damage occurring after that, even just a day later, led to large fibrotic scars. “I thought this was an intriguing paper that was well done,” says stem cell and regeneration biologist Richard Lee of Harvard University who was not involved with the work. “It pinpoints the timeline [of neonatal heart regeneration] in a manner that’s more precise than what others have done.”
That result is important and really relevant to human disease.—Joshua Hare,
University of Miama Miller School of Medicine
Other scientists are skeptical that what the researchers observed is true regeneration. Clinical biochemist Ditte Andersen of the University of Southern Denmark who has removed small portions ...
