The role of gastric microbiota in gastric cancer

ABSTRACT

Gastric cancer represents one of the leading causes of cancer deaths worldwide. Helicobacter pylori (H. pylori) infection is the strongest risk factor associated with gastric cancer. Due to new molecular techniques allowing greater identification of stomach microbes, investigators are beginning to examine the role that bacteria other than H. pylori play in gastric cancer development. Recently, researchers have investigated how the composition of the gastric microbiota varies among individuals with various stages of gastric disease. Specific microbes residing in the stomach have been preferentially associated with gastric cancer patients compared to individuals with a healthy gastric mucosa. Studies conducted on the insulin-gastrin (INS-GAS) transgenic mouse model have provided additional insight into the association between the gastric microbiota and gastric cancer. The purpose of this article is to review the current state of literature on the relationship between the gastric microbiota and gastric cancer based on clinical studies performed to date.     

胃起搏对胃动力紊乱犬胃排空及胃肌电活动的影响

目的　研究胃起搏对胃动力紊乱犬胃排空及胃电参数的影响。方法　采用双侧迷走神经干切断术联合应用胰高血糖素建立胃动力紊乱犬模型 ;采用 4导联胃肠电系统微机分析仪记录胃肠浆膜肌电活动 ;99mTc 植酸钠标记的半固体试餐 ,单光子计算机断层显像技术 (SPECT)检测胃半排空时间(GEt1/ 2 ) ;采用适宜起搏参数从胃体、胃窦在腹部投影部位输入起搏信号驱动胃电节律。结果　迷走神经干切断术后犬的GEt1/ 2 为 (79.4 2± 1.91)min ,较术前 (5 6 .35± 2 .99)min明显延迟 (P <0 .0 0 1) ,但行胃起搏治疗后GEt1/ 2 为 (6 4 .94± 1.75 )min ,较治疗前明显加快 (P <0 .0 0 1) ;胃起搏治疗前迷走神经干切断犬餐后的胃电频率为 (0 .0 81± 0 .0 0 7)Hz、胃电幅度为 (2 .32± 0 .35 )mV、慢波的传播速度为 (4 .0 6± 0 .4 0 )cm/s ,均较正常对照犬显著降低 [(0 .0 90± 0 .0 0 6 )Hz ,(4 .2 5± 0 .12 )mV ,(6 .92± 0 .2 4 )cm/s,(P <0 .0 5 ) ],治疗后其餐后胃电频率 (0 .0 92± 0 .0 0 5 )Hz、胃电幅度 (3.97± 0 .19)mV和慢波的传播速度 (5 .5 7± 0 .4 8)cm/s均明显高于治疗前 (P <0 .0 5 )。结论　采用适宜起搏参数输入起搏信号可完全触发胃电慢波 ,改善胃电参数 ,纠正药物导致的异常胃电节律 ,加速胃排空 ,恢     

Serological assessment of gastric mucosal atrophy in gastric cancer

Background  

Non-invasive tools for gastric cancer screening and diagnosis are lacking. Serological testing with the detection of pepsinogen 1 (PG1), pepsinogen 2 (PG2) and gastrin 17 (G17) offers the possibility to detect preneoplastic gastric mucosal conditions. Aim of this study was to assess the performance of these serological tests in the presence of gastric neoplasia.     

Hemodynamics of the gastric mucosa and gastric ulceration in rats and in patients with gastric ulcer

The microcirculation is the fundamental nutrient supply and waste removal system of all tissues. Recent improvements in spectrophotometric technique have made possible the noninvasive assessment of oxygen supply and utilization in the gastric mucosa. The authors have utilized such methods to assess gastric mucosal hemodynamics. The technique permitted further clarification of the roles of the gastric microcirculation, mucosal oxygenation, and acid secretion in the pathogenesis of stress ulcers in the stomach of rats. Furthermore, it provided important information on the function of gastric mucosal hemodynamics in the healing of gastric ulcers in man. The technique is described along with the authors' correlation studies between spectrophotometric data and other techniques for measuring gastric blood flow (hydrogen gas clearance and aminopyrine clearance methods and direct electromagnetic flowmeter techniques) and the prevention of ulcerogenesis.     

Shift of the gastric T-cell response in gastric carcinoma

BACKGROUND AND AIMS: The etiology and pathophysiology of stomach carcinoma is complex, and the mechanism whereby H. pylori directly or indirectly induces carcinoma remains unclear. In this study, interleukin (IL)-8, IL-4 and interferon (IFN)-gamma were measured in the tissue culture supernatant of gastric organ cultures from subjects with chronic gastritis with or without H. pylori infection, and with or without gastric cancer and gastric dysplasia. RESULTS: Interleukin-8 levels were higher in cancer- and H. pylori-infected gastritis subjects than in H. pylori-negative subjects (12.95 +/- 3.16, 10.48 +/- 1.55 and 4.49 +/- 1.28 ng/mL, respectively). Elevated levels of IFN-gamma were detected in both H. pylori-infected and non-infected subjects with uncomplicated gastritis (72.23 +/- 19.0 and 34.61 +/- 5.30 pg/mL) and in non-infected dysplasia subjects (88 +/- 20.5 pg/mL). Background levels of IL-4 (< or = 9.4 pg/mL) in uncomplicated gastritis subjects and relatively high levels of IL-4 in dysplasia subjects (25.8 +/- 7.3 pg/mL) were detected. In contrast, trace amounts of IFN-gamma (16.01 +/- 0.35 pg/mL) and high levels of IL-4 (42.81 +/- 8.49 pg/mL) in gastric biopsy culture supernatants were found in cancer subjects. Mucosal IL-4 levels (but not IL-8 levels) correlated with infection and mucosal anti-H. pylori immunoglobulin G antibody. CONCLUSIONS: The significant differences between gastritis with and without cancer and dysplasia indicated a shift from a Th1 to a Th2 helper cell pattern of cytokine secretion. This study has identified a local mucosal defect in gastric cancer. The near absence of IFN-gamma production from the mucosa at the margins of the tumor may be a critical factor in promoting growth of neoplastic cells.     

Characteristics of gastric mucus in elderly patients with gastric ulcers

BACKGROUND/AIMS: Studies of the most important defensive factor, gastric mucus, in the treatment of gastric ulcers in elderly patients have been lacking. Therefore we focused on the changes in gastric mucus during the ulcer-healing process in elderly patients. METHODOLOGY: Twenty elderly patients (> or = 65 years old), and 20 younger patients (< 65 years old) with gastric ulcers were administered antisecretory agents for 24 weeks. Biopsies were taken from the antrum and body of the stomach, and the levels of gastric mucosal hexosamine and periodic acid-Schiff-positive gastric mucus were measured. RESULTS: In both groups, the hexosamine levels in the specimens from the body of the stomach declined during the healing process. The decrease was more marked in the elderly, and the recovery of this level was also slower than in the younger group. The periodic acid-Schiff-positive mucosal index was also lower in the elderly. A decrease in body periodic acid-Schiff-positive mucus was seen with treatment in both groups, but recovery was slower in the elderly group. CONCLUSIONS: A decrease in gastric mucus, as a gastric mucosal defensive factor, was seen in gastric ulcers in elderly patients. The potential usefulness of the administration of mucosal protective agents for elderly patients with gastric ulcers was suggested.