Y recommended cholecystectomy in case of GAM with gallstones or symptomatic GAM because stones and Title Loaded From File chronic inflammation secondary to GAM may lead to dysplasia, metaplasia and cancer. Although no similar finding has been reported with respect to H.Title Loaded From File pylori infection and its association with GAM, we speculate that H.pylori might be involved in the development of GAM by altering cell kinetics and proliferative activity which were verified in chronic gastritis and gastric carcinogenesis. [32]. According to literatures, metaplasia of gallbladder mucosa presents in 5 ?9 of cholecystectomies. [33?5] In our study, metaplasia was identified in 7.67 of the included patients and it was shown to be statistically correlated with H. pylori infection in gallbladder mucosa (p = 0.047). Metaplasia is believed to be a strong histological sign for diagnosis of moderate or severe chronic cholecystitis because it is rarely observed in gallbladder autospy in which only mild inflammatory changes present. [36] Misra et al. [37] found that H. pylori colonises areas of metaplasia in gallbladder producing histological changes very similar to those seen in gastric mucosa. Chen et al. [38] demonstrated that metaplasia may provide suitable conditions for H. pylori colonization in the gallbladder. Their electron microscopy revealed at sites infected with H. pylori, the integrity of the cell-to-cell membrane of gallbladder epithelium was destructed, with swelling of mitochondria and dilatation of endoplasmic reticulum. In H.pylori-infected gallbladder nucosa, metaplasia lesions area accompanying with H.pylori colonization could be detected in 91.5 of the specimens. These morphological findings may indicate a potential direction for determining the role of H.pylori in the formation of metaplasia. Except metaplasia, hyperplasia and dysplasia were detected in 100 and 3.37 of the included patients, respectively. However, no significant correlation could be set up between these two kinds of pathological changes and H.pylori colonization in gallbladder mucosa. H.pylori can damage gastrointestinal epithelial cells through mediating chronic inflammation. In the pathogenesis of gastric cancer, H.pylori is proved to promote the expression of ROS/RNS mediated by NF-kB, AP-1 and other pathways. [39,40] High concentration of NO can lead to nitrative DNA damage and canceration of the epithelium. [41] In our study, the expression levels of ROS and iNOS were significantly increased in H.pylori infected gallbladder mucosa than that in non-infected mucosa. However, considering there were only 3 of the slides showed positive H. pylori staining and enhanced iNOS or ROS expressions occurring simultaneously in the same area, whether H. pylori could directly induce oxidative stress in gallbladder mucosa through increasing the expression of iNOS or ROS in gallbladder mucosa still needs further investigation. Recently, a study in vitro showed that H.pylori could significantly stimulate the growth of cholangiocarcinoma cell line (KKU-100) and DNA synthesis through iNOS pathway. [42] Unfortunately, no study so far has explored the role of H.pylori in the development 23977191 of chronic cholecystitis in normalHelicobacter pylori and Chronic Cholecystitisgallbladder epithelium with respect to cell proliferation, apoptosis, and inflammation.AcknowledgmentsWe thank Dr. Yong Yang and Dr. Ying-Bin Liu, Department of General Surgery, Xinhua Hospital, Shanghai JiaoTong University, School of Medicine, for th.Y recommended cholecystectomy in case of GAM with gallstones or symptomatic GAM because stones and chronic inflammation secondary to GAM may lead to dysplasia, metaplasia and cancer. Although no similar finding has been reported with respect to H.pylori infection and its association with GAM, we speculate that H.pylori might be involved in the development of GAM by altering cell kinetics and proliferative activity which were verified in chronic gastritis and gastric carcinogenesis. [32]. According to literatures, metaplasia of gallbladder mucosa presents in 5 ?9 of cholecystectomies. [33?5] In our study, metaplasia was identified in 7.67 of the included patients and it was shown to be statistically correlated with H. pylori infection in gallbladder mucosa (p = 0.047). Metaplasia is believed to be a strong histological sign for diagnosis of moderate or severe chronic cholecystitis because it is rarely observed in gallbladder autospy in which only mild inflammatory changes present. [36] Misra et al. [37] found that H. pylori colonises areas of metaplasia in gallbladder producing histological changes very similar to those seen in gastric mucosa. Chen et al. [38] demonstrated that metaplasia may provide suitable conditions for H. pylori colonization in the gallbladder. Their electron microscopy revealed at sites infected with H. pylori, the integrity of the cell-to-cell membrane of gallbladder epithelium was destructed, with swelling of mitochondria and dilatation of endoplasmic reticulum. In H.pylori-infected gallbladder nucosa, metaplasia lesions area accompanying with H.pylori colonization could be detected in 91.5 of the specimens. These morphological findings may indicate a potential direction for determining the role of H.pylori in the formation of metaplasia. Except metaplasia, hyperplasia and dysplasia were detected in 100 and 3.37 of the included patients, respectively. However, no significant correlation could be set up between these two kinds of pathological changes and H.pylori colonization in gallbladder mucosa. H.pylori can damage gastrointestinal epithelial cells through mediating chronic inflammation. In the pathogenesis of gastric cancer, H.pylori is proved to promote the expression of ROS/RNS mediated by NF-kB, AP-1 and other pathways. [39,40] High concentration of NO can lead to nitrative DNA damage and canceration of the epithelium. [41] In our study, the expression levels of ROS and iNOS were significantly increased in H.pylori infected gallbladder mucosa than that in non-infected mucosa. However, considering there were only 3 of the slides showed positive H. pylori staining and enhanced iNOS or ROS expressions occurring simultaneously in the same area, whether H. pylori could directly induce oxidative stress in gallbladder mucosa through increasing the expression of iNOS or ROS in gallbladder mucosa still needs further investigation. Recently, a study in vitro showed that H.pylori could significantly stimulate the growth of cholangiocarcinoma cell line (KKU-100) and DNA synthesis through iNOS pathway. [42] Unfortunately, no study so far has explored the role of H.pylori in the development 23977191 of chronic cholecystitis in normalHelicobacter pylori and Chronic Cholecystitisgallbladder epithelium with respect to cell proliferation, apoptosis, and inflammation.AcknowledgmentsWe thank Dr. Yong Yang and Dr. Ying-Bin Liu, Department of General Surgery, Xinhua Hospital, Shanghai JiaoTong University, School of Medicine, for th.