Detection of lactobacillus in the stomach of dyspeptic patients and its role in the suppression of tumor necrosis factor-α production in vitro

Abstract

Lactobacillus species represent indigenous microorganisms of the mammalian gastrointestinal tract and some specific strains can suppress the production of a number of proinflammatory cytokines including tumor necrosis factor-alpha (TNF-α). In this study, lactobacillus spp. were isolated from gastric biopsies of 272 dyspeptic patients that were divided into three groups by endoscopic findings as follows: groups one, 70 patients with mild gastritis; group two, 158 patients with severe gastritis and group three, 44 patients with peptic ulcer. Bacterial culture of gastric biopsies yielded 57 patients (20.96%) which were categorized into 9 patients (12.85%) in group one, 32 patients (20.25%) in group two and 16 patients (36.36%) in group three. Statistical analyses revealed that the prevalence of lactobacillus in patients groups one and two were not significantly different (p>0.05) but significantly different in patients groups two and three and patients groups one and three (p<0.05). Bacterial culture of throat swabs yielded 103 patients (37.87%) which were categorized into 25 patients (35.71%) in group one, 57 patients (36.08%) in group two and 21 patients (47.73%) in group three. Statistical analyses revealed that the prevalence of lactobacillus in each group of patients were not significantly different (p>0.05). The immunomodulating activities of lactobacillus isolated from gastric biopsies of 57 patients revealed 31 patients (54.39%) significantly suppressed LPS-activated TNF-α production by THP-1 monocytic cells (p<0.05). These TNF-α-inhibitory isolates were 7 patients (77.78%) in group one, 18 patients (56.25%) in group two and 6 patients (37.5%) in group 3. Statistical analyses revealed that the prevalence of TNF-α-inhibitory lactobacillus isolates in patients groups one and two v.s. groups two and three were not significantly different (p>0.05) but significantly different in patients groups one and three (p = 0.053). However, multivariate analysis of the prevalence of TNF-α-inhibitory lactobacillus in patients groups 1 and 3 was not significantly different (p = 0.985). TNF-α-inhibitory lactobacillus found in this study were all isolates of lactobacillus plantarum, L.murinus and some isolates of L.salivarius, L.gasseri and L.casei group. On the contrary, all isolates of L. fermentum, L. mucosae and L.oris did not suppress TNF-α production. Predominate species found in both gastric biopsies and throat were L.fermentum and L.salivarius. Of 38 patients from whom lactobacillus spp. were recovered from both gastric biopsies and throat swabs, 28 (73.68%) had at least one isolate of the same species. The results of this study suggested that some lactobacillus species detected in gastric biopsies originate from throats and lactobacillus species in the stomach might be a factor contributing to the pathogenesis of peptic ulcer