Worm Can Regenerate Entire Body With One Cell

You might have heard of stem cells being the future for medicine. This is because certain types of stem cells, called pluripotent stem cells, can generate into an kind of cell in the body. However, these cells are only found in embryos and therefore, are extremely rare. Stem cells found on adults have more specificity. For example, blood stem cells can generate into any cell type that constitutes blood but cannot generate into, for example, a nerve cell.

In a recent discovery, scientists in MIT and Howard Hughes Medical Institute found that flat worms, or planarians, have pluripotent stem cells in adults. This is first time any such cells have been found in an adult animal.

Flat worms have been known to regenerate themselves from a just a chunk of tissue. This amazing regenerative ability resulted in a study by scientists to figure whether this is attributed to a bunch of specialized stem cells working together or just an "all purpose" cell. To do this, scientists exposed several worms to radiation that stops their cells from diving. A certain type of cell, called the cNeoblast, was spared of the radiation exposure to see if this is the cell responsible for regeneration. As the other cells slowly died out because they cannot reproduce, the scientists watched as the cNeoblasts took over and generated a new batch of healthy, replacement tissue.

However, even with this information in hand, it did not stop the scientists from doing something truly weird. They implanted a single cNeoblast cell from one type of planarian in another type which did not have its own cNeoblasts. The latter worm, was exposed to a lethal dose of radiation beforehand that stopped reproduction in all its cells. As the worm started to die, the cNeoblast cell started multiplying and specializing into different cells and "ultimately replaced all the host's tissues" with new healthy ones. The resulting worm was an exact genetic copy of the original cNeoblast donor.

Scientists hope that some day, they can figure out how these cells work and possibly study ways to use these cells for human tissue regeneration.