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Researchers have discovered a human glycoprotein, inhibits Helicobacter pylori ("H. pylori"), the bacterium that causes stomach ulcers and is linked with 90 percent of stomach cancers. These results present a new way of looking at treating the chronic inflammation associated with stomach ulcers, and introduces the possibility of preventing stomach cancer associated with H. pylori. Just as important: This is also the first time a glycoprotein has been shown to work like an antibiotic.
More than 50 percent of the world's population is infected with H. pylori, yet only 2 percent are afflicted with stomach ulcers and only 1 percent with stomach cancer. H. pylori is found in mostly in the stomach, where it thrives in the superficial mucin layer lining the stomach. The bacterium is rarely found in the deeper portion of the mucin layer, where the mucous cells produce a particular class of glycoproteins, called O-glycans, linked with the carbohydrate alpha 1,4-N-acetylglusoseamine, cloned previously.
Because the alpha 1,4-linked N-acetylgucosamine is confined to the stomach's deeper mucosa lining, which also lacks H. pylori, scientists investigated the possibility that it might play a role against infection by H. pylori.
They isolated mucin from the upper and lower layers and found a key difference: surface-derived mucin actively supported H. pylori growth, while mucins from the second layer inhibited growth. H. pylori in the presence of alpha 1,4-linked N-acetylgucosamine lost its shape, became immobile, and eventually died. This cell-growth immobilizing effect is very similar to the effect of antibiotics, which dissolve the bacterium's cell wall.
EurekAlert August 12, 2004