H. pylori decreases gastric mucin synthesis via inhibition of galactosyltransferase.
OBJECTIVE
Alterations of gastric mucin have been postulated as important pathogenic properties of Helicobacter pylori. In this study, we investigated gastric mucin synthesis in H. pylori-infected gastric mucosa by measuring UDP-galactosyltransferase activity, a key enzyme for the synthesis of mucin, and the amount of intracellular mucin in the gastric mucosa.


METHODS
Gastric biopsy specimens were obtained from thirty-seven patients (20 H. pylori-positive and 17 H. pylori-negative). UDP-galactosyltransferase activity of the biopsy specimens was measured by an assay system we had developed, using a peanut agglutinin lectin. The amount of intracellular mucin in the gastric epithelial cells was analyzed by measuring the cells' periodic acid-Schiff-alcian blue staining-positive substances.


RESULTS
UDP-galactosyltransferase activities in the antral mucosa, but not in the body mucosa, of H. pylori-positive patients were significantly lower than those of H. pylori-negative patients (p < 0.05). The amount of intracellular mucin in antral epithelial cells of H. pylori-positive patients was significantly lower than that of H. pylori-negative patients (p < 0.01).


CONCLUSIONS
These findings suggest that H. pylori infection decreases gastric mucin synthesis via inhibition of UDP-galactosyltransferase. This effect may impair the gastric mucosal barrier and contribute to the mucosal injury induced by H. pylori infection.
Tanaka
Shouichi
S
Department of Medicine and Medical Science, Okayama University Graduate School of Medicine and Dentistry, 2-5-1 Shikata-cho, Okayama 700-8558, Japan.
Mizuno
Motowo
M
Maga
Toshirou
T
Yoshinaga
Fumiya
F
Tomoda
Jun
J
Nasu
Junichirou
J
Okada
Hiroyuki
H
Yokota
Kenji
K
Oguma
Keiji
K
Shiratori
Yasushi
Y
Tsuji
Takao
T
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005700:Galactosyltransferases / Q000378:metabolism*; D005752:Gastric Mucins / Q000096:biosynthesis*; D016481:Helicobacter Infections / Q000201:enzymology*; D016480:Helicobacter pylori; D006801:Humans; D008297:Male; D008875:Middle Aged
D005752:Gastric Mucins; D005700:Galactosyltransferases