Classification of Changes in the Fecal Microbiota Associated with Colonic Adenomatous Polyps Using a Long-Read Sequencing Platform.

The microbiota is the community of microorganisms that colonizes the oral cavity, respiratory tract, and gut of multicellular organisms. The microbiota exerts manifold physiological and pathological impacts on the organism it inhabits. A growing body of attention is being paid to host-microbiota interplay, which is highly relevant to the development of carcinogenesis. Adenomatous polyps are considered a common hallmark of colorectal cancer, the second leading cause of carcinogenesis-mediated death worldwide. In this study, we examined the relevance between targeted operational taxonomic units and colonic polyps using short- and long-read sequencing platforms. The gut microbiota was assessed in 132 clinical subjects, including 53 healthy participants, 36 patients with occult blood in the gut, and 43 cases with adenomatous polyps. An elevation in the relative abundance of Klebsiella pneumonia, Fusobacterium varium, and Fusobacterium mortiferum was identified in patients with adenomatous polyps compared with the other groups using long-read sequencing workflow. In contrast, the relatively high abundances of Blautia luti, Bacteroides plebeius, and Prevotella copri were characterized in the healthy groups. The diversities in gut microbiota communities were similar in all recruited samples. These results indicated that alterations in gut microbiota were characteristic of participants with adenomatous polyps, which might be relevant to the further development of CRC. These findings provide a potential contribution to the early prediction and interception of CRC occurrence.

An Overview of Gut Microbiota and Colon Diseases with a Focus on Adenomatous Colon Polyps.

It is known and accepted that the gut microbiota composition of an organism has an impact on its health. Many studies deal with this topic, the majority discussing gastrointestinal health. Adenomatous colon polyps have a high prevalence as colon cancer precursors, but in many cases, they are hard to diagnose in their early stages. Gut microbiota composition correlated with the presence of adenomatous colon polyps may be a noninvasive and efficient tool for diagnosis with a high impact on human wellbeing and favorable health care costs. This review is meant to analyze the gut microbiota correlated with the presence of adenomatous colon polyps as the first step for early diagnosis, prophylaxis, and treatment.

Helicobacter pylori Eradication Regressed Gastric Hyperplastic Polyp: A Randomized Controlled Trial.

BACKGROUND: Helicobacter pylori infection and hyperplastic polyp are known to have strong connections, but there are not enough randomized controlled trial data. AIMS: To evaluate the effect of H. pylori eradication on gastric hyperplastic polyp. METHOD: This is an open-labeled, single-center, randomized controlled trial. Patients with hyperplastic polyp and current infection of H. pylori were randomly assigned to eradication or non-eradication groups. All participants underwent follow-up endoscopy to investigate the regression of gastric polyps. Gastric polyp regression was defined as the disappearance of polyps or a reduction of more than 50% in size. RESULTS: Thirty-two patients were randomized to eradication (n = 17) and non-eradication groups (n = 15). Final included patients were 14 in eradication group and 13 in non-eradication group. All patients showed polyp regression in eradication group, whereas no regression was observed in non-eradication group (P < 0.001). Disappearance of polyp (n = 7) and decrease in size (n = 7) were observed in eradication group. In non-eradication group, no change (n = 5), increase of size (n = 5), and increase of number (n = 3) were observed. Mean regression time was 6.8 months, and disappearance time was 9.8 months. In non-eradication group, hyperglycemia was noted in 50% of progression group but not noted in no change group (P = 0.057). CONCLUSIONS: H. pylori eradication induced regression of hyperplastic polyp, and persistent H. pylori infection was related to progression of gastric polyp. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT03065868.

Moderate alteration to gut microbiota brought by colorectal adenoma resection.

BACKGROUND AND AIM: Microbial dysbiosis is involved in the development of colorectal cancer and its most common precancerous lesion, colorectal adenoma. Endoscopic resection is one of the procedures for primary prevention of colorectal cancer, yet little is known about how the endoscopic therapy influences gut microbiota. METHODS: We conducted a prospective study of 20 patients who underwent endoscopic resection of colorectal adenoma and analyzed the fecal microbiota before and 3 months after adenoma resection. MiSeq sequencing of 16S rRNA genes was performed to determine the alterations in microbial diversity and structure. To discriminate the microbiota of the two groups, random forest and receiver operating characteristic analysis were applied, and a genus-based microbiota signature was obtained. RESULTS: Despite few alterations in overall microbial structure after adenoma resection, the abundance of Parabacteroides revealed a significant increase postoperatively (3.8% vs 1.5%, 0.1160), and the microbiota signature of Parabacteroides, Streptococcus, and Ruminococcus showed an optimal discriminating performance of postoperative status with the area under the curve 0.788, P < 0.001. CONCLUSION: Fecal microbial alterations indicate the moderate influence of adenoma resection on gut microbiota and lay the groundwork for microbial prediction of adenoma recurrence. Larger sample studies are further required to validate the findings.

Colonic adenoma-associated Escherichia coli express specific phenotypes.

Specific Escherichia coli strains have been associated to colorectal cancer, while no data are available on genotypic and phenotypic features of E. coli colonizing premalignant adenomatous polyps and their pathogenic potential. This study was aimed at characterizing isolates collected from polyps and adjacent tissue in comparison with those from normal mucosa. From colonoscopy biopsies, 1500 E. coli isolates were retrieved and genotyped; 272 were characterized for phylogroup and major phenotypic traits (i.e., biofilm formation, motility, hemolysins, and proteases). Selected isolates were analyzed for extraintestinal pathogenic E. coli (ExPEC)-associated virulence genes and in vivo pathogenicity using Galleria mellonella. The majority of isolates collected from polyps were strong biofilm and poor protease producers, whereas those isolates from normal mucosa were highly motile, proteolytic and weak biofilm formers. Isolates from adjacent tissues shared features with those from both polyps and normal mucosa. Among selected E. coli isolates, ExPEC gene content/profile was variable and uncorrelated with the tissue of collection and larval mortality. Despite the heterogeneous virulence-gene carriage of the E. coli intestinal population, E. coli colonizing colonic adenomatous polyps express specific phenotypic traits that could represent an initial pathoadaptation to local environmental changes characterizing these lesions.

Applying simple linear combination, multiple logistic and factor analysis methods for candidate fecal bacteria as novel biomarkers for early detection of adenomatous polyps and colon cancer.

BACKGROUND: Colorectal cancer (CRC) is the third leading cause of cancer, and presents a considerable disease burden, worldwide. Recently, the gut microbiota has been proposed as a potential risk factor for CRC, and even adenomatous polyps (AP). Here, the aim of this study was to investigate the role of selected gut bacteria as fecal bacterial biomarkers, in early detection of CRC and AP. MATERIAL AND METHODS: Fecal samples (n = 93) were collected from Taleghani Hospital, Tehran, Iran, between 2015 and 2017, from normal controls (NC), AP cases and CRC stage I patients, who were undergoing screening for colonoscopy. Absolute quantitative real time PCR (qPCR) assays were established for the quantification of bacterial marker candidates, in all cases and control groups. In order to evaluate the diagnostic value of bacterial candidates in distinguishing CRC from a polyp, receiver operating characteristic curve (ROC) was performed. Multiple logistic regressions were used to find the best combinations of the bacterial candidates, then, combinations were analyzed based on three methods, including linear combination, multiple logistic and factor analysis models. RESULTS: According to the logistic model, combination of Fusobacterium nucleatum, Enterococcus feacalis, Streptococcus bovis, Enterotoxigenic Bacteroides fragilis (ETBF) and Porphyromonas spp. showed improved diagnostic performance, compared to each bacterium alone, as area under the receiver operating characteristic (AUROC) increases to 0.97, with 95% confidence interval. It was found that a simple linear combination was an appropriate model for discriminating AP and CRC cases, compared to the NC, with a sensitivity of 91.4% and specificity of 93.5%. CONCLUSION: Our results indicated that based on fecal bacterial candidates, statistical simple linear combination model and ROC curve analysis, early detection of AP and CRC might be possible.

The gastric mucosal-associated microbiome in patients with gastric polyposis.

The characteristics of the gastric microbiota in patients with gastric polyposis (GP) remain unclear. Given this we collected gastric antrum and gastric body biopsies from healthy controls (HC.A and HC.B group) and gastric antrum, gastric body and polyp biopsies from patients with multiple gastric polyps (GP.A, GP.B and GP.P group) for 16S rDNA sequencing. The results showed that the diversity of the gastric flora in the GP group was significantly lower than that of the HC group. The gastric flora composition of the GP group was significantly different from the HC group. However, flora diversity and compositions in different parts of the stomach (gastric antrum, gastric body or polyp tissue) were not significantly different. H. pylori abundance could influence the composition of gastric microbiota. Meanwhile, patients with fundic gland polyps (FGPs) and those with hyperplastic polyps (HPs) had considerably similar gastric bacterial compositions. We constructed a microbial dysbiosis index (MDI) based on the gastric microbiota at the genus level as a predictive model, and it was able to distinguish between individuals in the GP and HC groups. These findings showed that intragastric flora dysbiosis may be closely related to the occurrence and development of gastric polyps.

Mucosal microbiota of intestinal polyps reveals putative biomarkers of colorectal cancer.

The human intestine retains a complex microbial ecosystem, which performs crucial functions that impact on host health. Several studies have indicated that intestinal dysbiosis may impact on the establishment of life-threatening intestinal diseases such as colorectal cancer. An adenomatous polyp is the result of abnormal tissue growth, which is benign but is considered to be associated with a high risk of developing colorectal cancer, based on its grade of dysplasia. Development of diagnostic tools that are based on surveying the gut microbiota and are aimed at early detection of colorectal cancer represent highly desirable target. For this purpose, we performed a pilot study in which we applied a metataxonomic analysis based on 16S rRNA gene sequencing approach to unveil the composition of microbial communities of intestinal polyps. Moreover, we performed a meta-analysis involving the reconstructed microbiota composition of adenomatous polyps and publicly available metagenomics datasets of colorectal cancer. These analyses allowed the identification of microbial taxa such as Faecalibacterium, Bacteroides and Romboutsia, which appear to be depleted in cancerogenic mucosa as well as in adenomatous polyps, thus representing novel microbial biomarkers associated with early tumor formation. Furthermore, an absolute quantification of Fusubacterium nucleatum in polyps further compounded the important role of this microorganism as a valuable putative microbial biomarker for early diagnosis of colorectal cancer.

Immunohistochemical study of mucins in human intestinal spirochetosis.

Most patients with human intestinal spirochetosis (HIS; a colorectal bacterial infection caused by Brachyspira species) seem asymptomatic, and its pathogenicity remains unclear. Recently, alterations in mucin expression were reported in animal Brachyspira infection. The present question was "Is mucin expression altered in HIS?" Using antibodies for MUCs 1, 2, 4, 5AC, and 6, we immunohistochemically compared 215 specimens from 83 histology-confirmed HIS cases with 106 specimens from 26 non-HIS cases. Positive staining (which included even focal positive staining) was rated "high (+)" or "low (+)." Results were analyzed for 4 categories of lesions, and associations between MUC expression and spirochetal presence were also analyzed. In the "specimens without polyps or adenocarcinoma" category, high (+) MUC2 positivity was more frequent in HIS than in control. In the hyperplasia/serrated polyp category, in HIS (versus control), the MUC5AC positivity rate was lower, whereas high (+) MUC4 positivity was more frequent. In the conventional adenoma category, in HIS (versus control), the MUC1 positivity rate was lower, whereas both high (+) MUC2 positivity and high (+) MUC5AC positivity were less frequent. In the adenocarcinoma category, high (+) MUC2 positivity was more frequent in HIS than in control. Among the above mucins, only MUC1 positivity was significantly associated with an absence of the so-called fringe formation, an absence of spiral organisms within mucus, and an absence of strong immunopositive materials within the epithelial layer and within the subepithelial layer. The results suggest that Brachyspira infection or a related change in the microbiome may alter the large intestine mucin expression profile in humans.

Gastric polyps diagnosed by double-contrast upper gastrointestinal barium X-ray radiography mostly arise from the Helicobacter pylori-negative stomach with low risk of gastric cancer in Japan.

BACKGROUND: Double-contrast upper gastrointestinal barium X-ray radiography (UGI-XR) is a method broadly used for gastric cancer screening in Japan. Gastric polyp is one of the most frequent findings detected by UGI-XR, but how to handle it remains controversial. METHODS: Gastric polyps of the 17,264 generally healthy subjects in Japan who underwent UGI-XR or upper gastrointestinal endoscopy (UGI-ES) in 2010 were analyzed. RESULTS: Of the 6,433 UGI-XR examinees (3,405 men and 3,028 women, 47.4 ± 9.0 years old), gastric polyps were detected in 464 men (13.6 %) and 733 women (24.2 %) and were predominantly developed on the non-atrophic gastric mucosa (p < 0.0001). Multiple logistic regression analysis showed that the presence of gastric polyps has significant association with lower value of serum anti-Helicobacter pylori IgG titer, female gender, lighter smoking habit, older age, and normal range of body mass index (≥18.5 and <25), but not with drinking or serum pepsinogen I/II ratio. During the 3-year follow-up, gastric cancer occurred in 7 subjects (0.11 %), but none of them had gastric polyps at the beginning of the follow-up period. Of the 2,722 subjects with gastric polyps among the 10,831 UGI-ES examinees in the same period, 2,446 (89.9 %) had fundic, 267 (9.8 %) had hyperplastic, and 9 (0.3 %) had adenomatous/cancerous polyps. CONCLUSIONS: Gastric polyps diagnosed by UGI-XR predominantly arise on the Helicobacter pylori-negative gastric mucosa with a low risk of gastric cancer in Japan. In the prospective observation, none of the UGI-XR examinees with gastric polyps developed gastric cancer for at least 3 years subsequently.

Shifts in the Fecal Microbiota Associated with Adenomatous Polyps.

BACKGROUND: Adenomatous polyps are the most common precursor to colorectal cancer, the second leading cause of cancer-related death in the United States. We sought to learn more about early events of carcinogenesis by investigating shifts in the gut microbiota of patients with adenomas. METHODS: We analyzed 16S rRNA gene sequences from the fecal microbiota of patients with adenomas (n = 233) and without (n = 547). RESULTS: Multiple taxa were significantly more abundant in patients with adenomas, including Bilophila, Desulfovibrio, proinflammatory bacteria in the genus Mogibacterium, and multiple Bacteroidetes species. Patients without adenomas had greater abundances of Veillonella, Firmicutes (Order Clostridia), and Actinobacteria (family Bifidobacteriales). Our findings were consistent with previously reported shifts in the gut microbiota of colorectal cancer patients. Importantly, the altered adenoma profile is predicted to increase primary and secondary bile acid production, as well as starch, sucrose, lipid, and phenylpropanoid metabolism. CONCLUSIONS: These data hint that increased sugar, protein, and lipid metabolism along with increased bile acid production could promote a colonic environment that supports the growth of bile-tolerant microbes such as Bilophilia and Desulfovibrio In turn, these microbes may produce genotoxic or inflammatory metabolites such as H2S and secondary bile acids, which could play a role in catalyzing adenoma development and eventually colorectal cancer. IMPACT: This study suggests a plausible biological mechanism to explain the links between shifts in the microbiota and colorectal cancer. This represents a first step toward resolving the complex interactions that shape the adenoma-carcinoma sequence of colorectal cancer and may facilitate personalized therapeutics focused on the microbiota. Cancer Epidemiol Biomarkers Prev; 26(1); 85-94. ©2016 AACR.

Effect of Helicobacter pylori infection and its eradication on the fate of gastric polyps.

OBJECTIVES: Western guidelines recommend Helicobacter pylori eradication in H. pylori-associated gastric polyps, but Korean medical insurance does not approve its eradication. The aim of this study is to evaluate the effect of H. pylori eradication on gastric polyps. METHODS: Participants in a large screening cohort underwent baseline and follow-up esophagogastroduodenoscopy and H. pylori testing. The association between gastric polyps and H. pylori was estimated using odds ratios (ORs) adjusted for confounding factors and 95% confidence intervals (CIs). The effect of H. pylori eradication on the fate of polyps was also evaluated. RESULTS: The screening cohort included 7603 participants (605 gastric polyps: 529 hyperplastic polyps, 63 fundic gland polyps, and 13 adenomas). H. pylori infection showed a positive association with hyperplastic polyps (OR 2.01; 95% CI 1.66-2.41), but was inversely related to fundic gland polyps (OR 0.05; 95% CI 0.02-0.17). Removed polyps by biopsy or endoscopic resection or tiny polyps less than 3 mm at baseline and positive conversion of H. pylori at follow-up were excluded. A total of 7060 persons were finally included to evaluate the effect of H. pylori eradication on the gastric polyp. Successful H. pylori eradication (OR 0.52; 95% CI 0.35-0.77) and persistent H. pylori-negative status (OR 0.59; 95% CI 0.46-0.76) reduced the risk of hyperplastic polyps compared with the persistent H. pylori-positive group. Successful H. pylori eradication markedly induced the disappearance of hyperplastic polyps compared with the persistent H. pylori-positive group (85.0 vs. 29.0%, P=0.001). CONCLUSION: H. pylori infection increased the risk of hyperplastic polyps in both cross-sectional and longitudinal settings, and its eradication induced regression of hyperplastic polyps.

Gut microbiome development along the colorectal adenoma-carcinoma sequence.

Colorectal cancer, a commonly diagnosed cancer in the elderly, often develops slowly from benign polyps called adenoma. The gut microbiota is believed to be directly involved in colorectal carcinogenesis. The identity and functional capacity of the adenoma- or carcinoma-related gut microbe(s), however, have not been surveyed in a comprehensive manner. Here we perform a metagenome-wide association study (MGWAS) on stools from advanced adenoma and carcinoma patients and from healthy subjects, revealing microbial genes, strains and functions enriched in each group. An analysis of potential risk factors indicates that high intake of red meat relative to fruits and vegetables appears to associate with outgrowth of bacteria that might contribute to a more hostile gut environment. These findings suggest that faecal microbiome-based strategies may be useful for early diagnosis and treatment of colorectal adenoma or carcinoma.

Immune response against Streptococcus gallolyticus in patients with adenomatous polyps in colon.

Our aim was to examine the humoral immune response against Streptococcus gallolyticus subspecies gallolyticus antigens in individuals subjected to a routine colonoscopy in which colon adenomatous polyps were present or not. Serum samples from 133 individuals with adenomatous polyps and serum samples from 53 individuals with a normal colonoscopy were included. Western blot was performed in all subjects using a whole cell antigen from S. gallolyticus ATCC 9809, and rabbit antisera against the whole cell bacteria was prepared as a control. By analyzing the immune profile of the rabbit-immunized sera by Western-blot, at least 22 proteins were identified as immunogenic in S. gallolyticus. When we evaluated sera from human subjects, two proteins of approximately 30 and 22 kDa were most prominent. Based on this 2-protein band pattern, Western-blot profiles from human subjects were compared. The detection of a protein band of 22 kDa was associated with the presence of adenomatous polyps in colon [odds ratios (OR) 7.98, 95% confidence intervals (CI): 3.54-17.93], p < 0.001. When the presence of the 30 kDa protein alone or both the 22 and 30 kDa proteins were analyzed, the OR increased to 22.37 (95% CI: 3.77-131.64), p < 0.001. The specificity was 84.9 for the presence of the 22 kDa protein, and 98.1 for the presence of the 30 kDa protein alone or both 22 and 30 kDa bands. Serum from individuals with adenomatous polyps recognized two proteins from S. gallolyticus. This result confirmed the possible association of S. gallolyticus with adenomatous polyps in the colon.

Intestinal spirochaetosis associated with hyperplastic and adenomatous colonic polyps.

Intestinal spirochaetosis is a human colonic infection due to Brachyspira aalborgi and Brachyspira pilosicoli causing various abdominal complaints. Although the presence of healthy epithelial cells was hypothesized to be essential for the adhesion of spirochaetes to the colonic mucosa, their adhesion to hyperplastic and adenomatous colonic polyps has been observed recently. We report a case of a woman with long-standing abdominal symptoms, in whom spirochaetes were found on the colonic mucosa surrounding an adenocarcinoma in the biopsies collected during eight years of follow-up. Spirochaetes were found attached to normal mucosa, to hyperplastic and to adenomatous polyps, but not to the epithelium of the carcinoma. The rectal biopsy collected during the last follow-up colonoscopy was subjected to histopathology and to a specific examination for brachyspires, demonstrating the presence of B. pilosicoli DNA. This report could stimulate microbiological investigations during the follow-up of colonic polyps in order to explain whether the persistence of abdominal symptoms in such patients could be caused by a colonic spirochaetosis susceptible to eradication by a targeted therapy.

[Histopathologic and immunohistochemic changes in Helicobacter pylori colonised gastric mucosa]. / Modificarile histopatologice si imunohistochimice din mucoasa gastrica colonizata de Helicobacter pylori.

UNLABELLED: Helicobacter pylori (H. pylori) colonize gastric mucosa causing both inflammatory changes, premalignant lesions and malignant tumors, including gastric lymphoma and carcinoma. In this study, our propose was to evaluate the histopathological changes corellated with immunohistochemical results demonstrating the types of cellular infiltration and proliferative activity of gastric mucosa infected with H. pylori. MATERIAL AND METHOD: Gastric endoscopic examinations was performed in 468 patients with anti-H. pylori antibodies and dispeptic phenomena. Snippets harvested endobiopsic stomach were fixed in formalin and processed by paraffine inclusion. Histological sections were stained with hematoxylin-eosine and Giemsa. In 65 cases of endobiopsic fragments (36 deep chronic gastritis with intestinal metaplasia, glandular atrophy and intraepithelial neoplasia and 29 carcinomas) immunohistochemical reactions were performed by applying reagents for evidence of H. pylori colonies, of T lymphocytes (CD3) and macrophages (CD68) and Ki-67 reagent for proliferating nuclear antigen labelling. RESULTS: Endobiopsic specimen found in all H. pylori or by Giemsa staining or by anti-H. pylori antibodies when they were in small numbers. Histologically, were diagnosed : 463 superficial and deep chronic gastritis associated with premalignant lesions, 29 carcinomas, 2 non-Hodgkin's lymphoma and an adematous polyp. Immunohistochemically, inflammatory infiltrate consisted of numerous T lymphocytes, macrophages and lymphoid follicles. Foveolar cell nuclei, in areas of intraepithelial neoplasia and carcinomatous cells were intensely stained with Ki-67, demonstrating increased proliferation. CONCLUSIONS: In gastric infection with H. pylori, inflammatory infiltrat is composed of abundant macrophages and T lymphocytes. Ki-67 was absent or minimal in chronic gastritis, while in areas of intraepithelial neoplasia was positive in both foveolar and coating epithelium. Anti-H. pylori antibodies in human serum remains one of the simplest methods to detect H. pylori, therefore it plays an important role in practice. Medical eradication of bacteria may cancel inflammatory changes, metaplasia and proliferation of gastric mucosa and thus it prevents the cascade of carcinogenesis.

Helicobacter pylori infection is associated with colon adenomatous polyps detected by high-resolution colonoscopy.

Helicobacter pylori (H. pylori) is associated with the development of cancer in the stomach, but both positive and negative associations were reported with colorectal neoplasia. We sought to determine whether H. pylori is associated with colon neoplasia in Japanese population. We examined 332 patients who underwent routine high-resolution total colonoscopy and serologic testing for IgG antibodies agonist H. pylori. Subjects who received cyclooxygenase-2 inhibitors or previous eradication therapy and those with borderline titer levels were excluded from data analysis (n = 27). Seronegative control subjects were from the same study population to maximize the representativeness. There were no significant differences in age and gender between the 2 patient groups. A significant increase in the incidence of adenomatous polyps (p < 0.0001) and decrease in normal colonoscopic findings (p < 0.0005) were observed in seropositive patients than those seronegative. Our study indicates an etiological link of H. pylori infection to colorectal neoplasia and the need of routine colonoscopy in seropositive patients.