A little worm called Caenorhabditis elegans helped three scientists win a Nobel Prize. They won it for studying the early part of the little worm's short life span, which lasts somewhere between twelve and eighteen days. Now another team of scientists is studying the end of the worm's life span; they think that what they've discovered so far may prove valuable to humans as they too grow older.
The worm, which measures only a millimeter long, begins its life moving about at a fast pace, but after a while it slows down. Scientists guessed that the worm's nervous system was gradually weakening, nerve cells were dying, and that this was responsible for the worm's sluggishness. But to their surprise, they found that the nervous system didn't change at all with age; no nerve cells were lost.
It's the same scenario in humans. As people age, if they're healthy anyhow, they don't seem to lose nerve cells. However, what does change over time for both humans and this little worm is muscle tissue. As people age their muscles undergo a process called sarcopenia, meaning that they lose muscle mass and become weaker. This worm seems to suffer the same fate. For instance, muscle fibers, in both the worm and humans, are normally bundled together neatly, but as both species age they become disorganized.
Though the worm is indeed a simpler organism than humans, the team of scientists thinks that further study of the worm's weakening muscles may lead to a treatment for sarcopenia in humans.