You can't help but think of the babelfish in the Hitchhiker's Guide to the Galaxy with this story: scientists are hoping to combat hearing loss thanks to new research on the zebrafish. Find out how in the full article.

Talk about putting new meaning to the phrase "bare all." *chuckle* A recent report bannered researchers who've come up with a way to keep a fish species' time-limited, see-through features consistent throughout its entire life. And of course, they do this in the name of science - health science in particular - to study the growth of cancer cells and tumors on living organisms. This way, they could find more effective ways of combating cancer.

Thanks to the zebra fish, researchers may now actually reveal the secrets of the process of heart regeneration. Why them fish? Because they can regenerate their hearts. Smart, eh? According to Kenneth Poss and his colleagues over at Duke University, the Danio rerio (zebra fish) heal their hearts (oh, but that just sounds so cheesy...) through two synchronized steps.

What happens is, within five days, after having removed about 20 percent of an adult zebra fish heart ventricle, there appears undifferentiated progenitor cells lining the injured area, which will then turn into cardiac muscle cells.  These new muscle cells will then grow and divide, thus constructing a new heart muscle. While this is happening, meanwhile, a cell layer surrounding the heart and influencing the embryonic heart development - the developmental genes in the epicardium - are switched on, thereby activating the epicardial cells. 

Most of the cells will produce a new layer to protect the regenerating heart muscle, and to "bandage" the wound. Others, says Poss, will also create blood vessels for the growing muscle, "fulfilling the same role as they do when the embryonic heart develops."

A chemical produced by the heart muscles operates as a growth factor signal so that the two processes will converge and mend the heart. It activates the receptors on the surface of the epicardial cells as a signal that it needs to form a new heart lining. However, if a miscommunication ensues between the two cell types (ie. blockage), the regeneration cannot be completed and the heart scars.

Poss is putting up his hopes that colleagues will now "take a closer look at the epicardium in injured mammalian hearts and to potentially look at whether epicardial cells can be used therapeutically." The study appears in Cell's November 3rd issue.