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Human Saliva Heals Wounds

Compound in Human Saliva Seals Wounds. Eric Libby reports.

Anticipating a succulent meal, we begin to salivate. This complex mixture of over 200 proteins helps us digest our food. But Menno Oudhoff, a graduate student at the Amsterdam Academic Center for Dentistry, found another purpose for saliva in looking at the oral epithelial cells that line the mouth. It closes wounds.

It is known that rodents lick each other's wounds and that may speed up the healing process. But rat saliva, which contains high levels of growth hormones, is very different from what we produce. So Oudhoff collected saliva from healthy members of his lab.

Oral epithelial cells were grown in a thin layer on a dish. Some were scratched away to simulate a wound. Oudhoff then added saliva and the "wound" closed up.

But not all saliva works the same. Some people's saliva closed wounds more effectively than others. Oudhoff says not only is there a huge variation in saliva between people, but "also during the day, you have a different secretion rate -- when you sleep you hardly have any saliva."

Oudhoff determined that the active compound in human saliva wound closure is histatin, a known antifungal. This is present in humans and a couple of primate species, but not rodents.

Since our mouths are filled with bacteria, some pathogenic, Oudhoff says that wound-closing compounds like histatins may protect us from getting infections when we get a cut in our mouth. Still, without further study Oudhoff does not suggest people start licking their wounds.

This work was published online this month by The Journal of the Federation of American Societies for Experimental Biology.