About the size of toenail clippings, planarians are freshwater flatworms that can re-form from tiny slivers. This feature not only lets them repair themselves, but it lets them reproduce by breaking apart and then creating new worms. Many planarian bodily systems operate like ours. By studying how these features are reconstituted as the worms regenerate, scientists might move one step closer to replacing human tissue and cells lost to disease or injury. This image shows a cross-section of a flatworm. The magenta clusters and green specks throughout the planarian are structures that push waste toward bile ducts. The structures, which comprise the animal's excretory system, are like our kidneys in that they are lined with specialized cells. The ducts employ filtration methods similar to our kidneys, too. One key difference, though, is that flatworms can regenerate their excretory systems from next to nothing. To better understand how this regeneration happens, researchers removed the heads from planarians and watched as new excretory systems grew within a week. They uncovered a gene, EGFR5, that is necessary for the excretory structures to re-form during regeneration and for maintaining them in the intact animal. Studying similar genes in mammals could shed light on how we maintain our kidneys—and might repair damaged ones. Read more...
Featured in the August 16, 2012, issue of Biomedical Beat.