Influence of MDR1 polymorphism on H. pylori-related chronic gastritis

Background: There is evidence that changes in MDR1 function and/or expression contribute to the pathogenesis of inflammatory disorders of the gastrointestinal tract. Aims: We aimed to investigate the effect of C3435T polymorphism of the MDR1 gene on histological chronic gastritis, and on the risk of peptic ulcer diseases. Methods: Restriction fragment length polymorphism analysis was performed for polymorphisms at C3435T in the MDR1 gene in 556 cancer-free subjects including 116 gastric and 60 duodenal ulcers, and 380 non-ulcer subjects. Gastritis scores in the antrum were assessed according to the updated Sydney system in 384 subjects. Results: We did not find a significant association between MDR1 genotype and gastritis scores in any of the 384 subjects. However, the 3435T carrier was significantly associated with a higher degree of neutrophil infiltration in H. pylori-positive subjects (CC vs. T carrier: p = 0.0495). When the H. pylori positive subjects were divided according to generation, the 3435T carrier was significantly associated with a higher degree of neutrophil infiltration in subjects more than 65 years of age (CC vs. T carrier: p = 0.03). Also, the MDR1 3435 TT genotype was significantly associated with a higher degree of atrophy and intestinal metaplasia in the same generation (atrophy, TT vs. C carrier: p = 0.038, intestinal metaplasia, TT vs. C carrier: p = 0.016). No association was found between MDR1 genotypes and risk of peptic ulcer diseases. Conclusions: It appears that the C3435T polymorphism of MDR1 influences H. pylori-related inflammatory conditions in the stomach, especially in older subjects.