The effects of aerobic exercise on the intestinal tumors and flora of the ApcMin/+ mouse

INTRODUCTION

Intestinal tumor is one of the most common tumors that seriously threaten the health of residents all over the world. Studies suggest that the imbalance of intestinal flora is associated with tumorgenesis; meanwhile, long-term regular aerobic exercise can improve the occurrence and development of tumors. However, moderate aerobic exercise affecting the development of intestinal tumors and their related flora has not been explored. Thus, the purpose of our study is to explore the effects of aerobic exercise on intestinal tumor growth and flora changes in Apc^Min/+ mice, and try to answer whether there is a correlation between them after exercise intervention.

METHODS

In this study, 18 required Apc^Min/+ mice were randomly divided into Model group (n = 6), Exercise group (n = 6), and Aspirin group (positive control, n = 6), while C57BL/6 J wild-type mice were used as the blank control group. Each group is given corresponding intervention. Weight monitoring, tumor counts, hematoxylin-eosin staining, TdT-mediated dUTP nick-end labeling (TUNEL) fluorescence assay, immunohistochemistry (IHC), fecal sampling and grouping, and bacterial 16S rDNA gene analysis were completed after 12 weeks' intervention for each group of mice.

RESULTS

As a result, we were able to show significant improvements in mice' body weight changing rates (Exercise group 8.6% higher than Model control group), tumor numbers (Exercise group 4.33 ± 0.94 vs. Model control group 7.33 ± 2.49, Then put the slides into xylenewith tumor inhibition rate 40.93%), tumor pathological staging (Exercise group mainly low-grade tumorous adenomas vs. Model group mainly high-grade adenomas), and TUNEL staining (Exercise group 8.59% higher positive rate of apoptotic cells in tumors than Model group). The 16s rRNA sequencing analysis results showed that aerobic exercise could regulate the abundance of some genus (16/149, P < 0.01), and the number of intestinal tumors correlates with changes in the abundance of some bacteria in the intestinal flora (positive correlation with probiotics abundance and negative correlation with conditioned pathogens).

DISCUSSION

Changes in flora abundance may be one of the reasons for aerobic exercise to reduce the number of intestinal tumors, probably mediated by cell apoptosis. Future studies should focus on the potential mechanism of aerobic exercise in preventing intestinal tumorgenesis, especially the molecular mechanism through intestinal flora.

CONCLUSION

Aerobic exercise has a preventive effect on intestinal tumors in Apc^Min/+ mice, and can regulate the abundance of intestinal flora.

Functions of Dendritic Cells and Its Association with Intestinal Diseases

Dendritic cells (DCs), including conventional DCs (cDCs) and plasmacytoid DCs (pDCs), serve as the sentinel cells of the immune system and are responsible for presenting antigen information. Moreover, the role of DCs derived from monocytes (moDCs) in the development of inflammation has been emphasized. Several studies have shown that the function of DCs can be influenced by gut microbes including gut bacteria and viruses. Abnormal changes/reactions in intestinal DCs are potentially associated with diseases such as inflammatory bowel disease (IBD) and intestinal tumors, allowing DCs to be a new target for the treatment of these diseases. In this review, we summarized the physiological functions of DCs in the intestinal micro-environment, their regulatory relationship with intestinal microorganisms and their regulatory mechanism in intestinal diseases.

Helicobacter pylori cagE, cagG, and cagM can be a prognostic marker for intestinal and diffuse gastric cancer

It is known that Helicobacter pylori is the main cause of peptic ulceration and gastric cancer. However, there is a lack of information on whether H. pylori strains may differ in gastric cancer histological subtypes. This study aimed to investigate different H. pylori strains considering six cag Pathogenicity Island - cagPAI genes (cagA, cagE, cagG, cagM, cagT, and virb11), and vacuolating cytotoxin - vacA alleles, and their relation to gastric cancer histologic subtypes. For this purpose, tumor samples from 285 patients with gastric carcinoma were used. H. pylori infection and genotypes were determined by polymerase chain reaction (PCR). H. pylori was detected in 93.9% of gastric tumors. For comparative analyzes between histopathological subtypes considering H. pylori cagPAI genes the strains were grouped according to the vacA s1/s2 alleles. In the vacAs1 group, the strains cagA(-)cagE(+), cagA(+)cagE(+)cagG(+), cagA(+)cagM(+), or only cagE(+) strains were more frequent in the intestinal subtype (P = .009; P = .024; P = .046, respectively). In contrast, cagM(+)cagG(+)cagA(-) and cagE(-) were associated with diffuse tumors (P = .036), highlighting the presence of cagE in the development of intestinal tumors, and the presence of cagG and absence of cagE in diffuse tumors. Furthermore, WEKA software and Decision Tree (CART) analyses confirmed these findings, in which cagE presence was associated with intestinal tumors, and cagE absence and cagG(+) with diffuse tumors. In conclusion our results showed that vacAs1 (cagG + cagM) strains, mainly cagG positive with cagE absence, were relevant in the studied population for the diffuse outcome, while the presence of cagE was relevant for the intestinal outcome. These findings suggest the relevance of these H. pylori genes as potential markers for gastric cancer histological outcomes.

Endogenous murine microbiota member Faecalibaculum rodentium and its human homologue protect from intestinal tumour growth

The microbiota has been shown to promote intestinal tumourigenesis, but a possible anti-tumourigenic effect has also been postulated. Here, we demonstrate that changes in the microbiota and mucus composition are concomitant with tumourigenesis. We identified two anti-tumourigenic strains of the microbiota-Faecalibaculum rodentium and its human homologue, Holdemanella biformis-that are strongly under-represented during tumourigenesis. Reconstitution of ApcMin/+ or azoxymethane- and dextran sulfate sodium-treated mice with an isolate of F. rodentium (F. PB1) or its metabolic products reduced tumour growth. Both F. PB1 and H. biformis produced short-chain fatty acids that contributed to control protein acetylation and tumour cell proliferation by inhibiting calcineurin and NFATc3 activation in mouse and human settings. We have thus identified endogenous anti-tumourigenic bacterial strains with strong diagnostic, therapeutic and translational potential.

Transmission of a common intestinal neoplasm in zebrafish by cohabitation

Intestinal neoplasms are common in zebrafish (Danio rerio) research facilities. These tumours are most often seen in older fish and are classified as small cell carcinomas or adenocarcinomas. Affected fish populations always contain subpopulations with preneoplastic lesions, characterized by epithelial hyperplasia or inflammation. Previous observations indicated that these tumours are unlikely caused by diet, water quality or genetic background, suggesting an infectious aetiology. We performed five transmission experiments by exposure of naïve fish to affected donor fish by cohabitation or exposure to tank effluent water. Intestinal lesions were observed in recipient fish in all exposure groups, including transmissions from previous recipient fish, and moribund fish exhibited a higher prevalence of neoplasms. We found a single 16S rRNA sequence, most similar to Mycoplasma penetrans, to be highly enriched in the donors and exposed recipients compared to unexposed control fish. We further tracked the presence of the Mycoplasma sp. using a targeted PCR test on individual dissected intestines or faeces or tank faeces. Original donor and exposed fish populations were positive for Mycoplasma, while corresponding unexposed control fish were negative. This study indicates an infectious aetiology for these transmissible tumours of zebrafish and suggests a possible candidate agent of a Mycoplasma species.

Risk factors for intestinal metaplasia in a southeastern Chinese population: an analysis of 28,745 cases

PURPOSE

To identify risk factors for intestinal metaplasia in a southeastern Chinese population.

METHODS

Subjects who underwent upper GI endoscopy and endoscopic biopsy in the First Affiliated Hospital of Nanjing Medical University from 2008 to 2013 were included into this study. Various demographic, geographic, clinical and pathological data were analyzed separately to identify risk factors for intestinal metaplasia.

RESULTS

The incidence of intestinal metaplasia differed significantly in 17 municipal areas ranging from 16.79 to 38.56% and was positively correlated with the age range of 40-70 years, male gender, gastric ulcer, bile reflux, Helicobacter pylori infection, atrophic gastritis, dysplasia, gastric cancer, degree of chronic and acute inflammation, and gross domestic product per capita (P < 0.01). Multivariate linear regression analysis indicated that only gross domestic product per capita revealed a significant difference in the incidence of intestinal metaplasia among all factors mentioned.

CONCLUSION

This study confirms age, male gender, gastric ulcer, bile reflux, H. pylori infection, severe degree of chronic and acute inflammation to be the risk factors for intestinal metaplasia. We speculate that the gross domestic product per capita of different areas may be a potential independent risk factor impacting the incidence of intestinal metaplasia.

Diet- and Genetically-Induced Obesity Differentially Affect the Fecal Microbiome and Metabolome in Apc1638N Mice

Obesity is a risk factor for colorectal cancer (CRC), and alterations in the colonic microbiome and metabolome may be mechanistically involved in this relationship. The relative contribution of diet and obesity per se are unclear. We compared the effect of diet- and genetically-induced obesity on the intestinal microbiome and metabolome in a mouse model of CRC. Apc1638N mice were made obese by either high fat (HF) feeding or the presence of the Leprdb/db (DbDb) mutation. Intestinal tumors were quantified and stool microbiome and metabolome were profiled. Genetic obesity, and to a lesser extent HF feeding, promoted intestinal tumorigenesis. Each induced distinct microbial patterns: taxa enriched in HF were mostly Firmicutes (6 of 8) while those enriched in DbDb were split between Firmicutes (7 of 12) and Proteobacteria (5 of 12). Parabecteroides distasonis was lower in tumor-bearing mice and its abundance was inversely associated with colonic Il1b production (p<0.05). HF and genetic obesity altered the abundance of 49 and 40 fecal metabolites respectively, with 5 in common. Of these 5, adenosine was also lower in obese and in tumor-bearing mice (p<0.05) and its concentration was inversely associated with colonic Il1b and Tnf production (p<0.05). HF and genetic obesity differentially alter the intestinal microbiome and metabolome. A depletion of adenosine and P.distasonis in tumor-bearing mice could play a mechanistic role in tumor formation. Adenosine and P. distasonis have previously been shown to be anti-inflammatory in the colon and we postulate their reduction could promote tumorigenesis by de-repressing inflammation.

Endoscopic features of gastro-intestinal lymphomas: From diagnosis to follow-up

Many progresses have been done in the management of gastrointestinal (GI) lymphomas during last decades, especially after the discovery of Helicobacter pylori-dependent lymphoma development. The stepwise implementation of new endoscopic techniques, by means of echoendoscopy or double-balloon enteroscopy, enabled us to more precisely describe the endoscopic features of GI lymphomas with substantial contribution in patient management and in tailoring the treatment strategy with organ preserving approaches. In this review, we describe the recent progresses in GI lymphoma management from disease diagnosis to follow-up with a specific focus on the endoscopic presentation according to the involved site and the lymphoma subtype. Additionally, new or emerging endoscopic technologies that have an impact on the management of gastrointestinal lymphomas are reported. We here discuss the two most common subtypes of GI lymphomas: the mucosa-associated lymphoid tissue and the diffuse large B cell lymphoma. A general outline on the state-of-the-art of the disease and on the role of endoscopy in both diagnosis and follow-up will be performed.

The fire within: microbes inflame tumors

The immune system and the microbiota mutually interact to maintain homeostasis in the intestine. However, components of the microbiota can alter this balance and promote chronic inflammation, promoting intestinal tumor development. We review recent advances in understanding the complex interactions between the microbiota and the innate and adaptive immune systems and discuss their potential to lead us in new directions for understanding cancer biology and treatment.

Differential expression of MYC in H. pylori-related intestinal and diffuse gastric tumors

Evidence suggests that the carcinogenic process guided by Helicobacter pylori is related to the expression of cell cycle and apoptosis proteins as BCL-2, BAX, and MYC. However, the literature is conflicting regarding the expression frequency in the histological subtypes and did not consider cagA gene presence. To investigate the expression of these proteins considering the histological subtypes of gastric cancer associated with H. pylori (cagA), a total of 89 cases were used. H. pylori infection and cagA status were determined by PCR. Immunodetection was performed for MYC, BCL-2, and BAX proteins. H. pylori was found in 95.5% of the patients, among them, 65.8% were cagA(+). Nuclear MYC was detected in 36.4%, BAX in 55.7%, while BCl-2 in just 5%. Nuclear MYC staining was significantly lower in the intestinal than diffuse subtype (p = 0.008) and was related with the presence of H. pylori cagA(+). Additionally, most of the few cases cytoplasmic MYC positive were in the intestinal subtype. In diffuse tumors, although most nuclear MYC positive cases were cagA(+), it was not significant. No difference was observed between BCL-2 or BAX expression considering the presence of cagA gene in the histological subtypes. It seems that MYC could be relevant for the diffuse tumorigenic pathway associated with H. pylori and possibly influenced by the presence of cagA gene, while in intestinal tumors, the tumorigenic pathway does not occur through the MYC expression.

Polymorphisms of death pathway genes FAS and FASL and risk of premalignant gastric lesions

BACKGROUND

Tumorigenesis is a multistep process that begins with the abrogation of normal controls of apoptosis and cell proliferation, and the FAS receptor-ligand system is a key regulator of apoptosis. The aim of this study was to investigate whether functional polymorphisms of death pathway genes (FAS and FASL) are associated with the development of gastric atrophy and intestinal metaplasia.

PATIENTS AND METHODS

Genotypes in the promoter regions of the FAS (-1377G/A and -670A/G) and FASL (-844T/C) genes of 101 healthy individuals and 86 gastric cancer patients were determined by PCR-RFLP. Additionally, gastric histological changes were examined according to the updated Sydney System.

RESULTS

The carriage of FASL -844C allele significantly increased the risk of atrophy in the gastric corpus, with an adjusted odds ratio (OR) of 5.0 [95% confidence interval (CI), 1.5-6.8]. There were no gene-gene interactions among FASL -844T/C, FAS -1377G/A and FAS -670A/G polymorphisms in developing premalignant gastric lesions. In the 109 individuals with Helicobacterpylori infection, carrying the FAS -1377A allele was a protective factor for developing intestinal metaplasia in the antrum (OR, 0.3; 95% CI, 0.1-0.9), while carrying the FASL -844C allele was a risk factor for developing gastric atrophy in the corpus (OR, 9.4; 95% CI, 1.7-53.4).

CONCLUSION

FAS and FASL genotypes of the hosts are important determinants in the pathogenesis of gastric atrophy and intestinal metaplasia in H. pylori-infected individuals.

Association of polymorphisms in myeloperoxidase and catalase genes with precancerous changes in the gastric mucosa of patients at inner-city hospitals in New York

Gastric carcinogenesis is a multistep process progressing from chronic gastritis, through glandular atrophy (GA), intestinal metaplasia (IM) and dysplasia. We have previously demonstrated that minority patients at New York City hospitals are infected with a relatively virulent strain of H. pylori (Hp) and that Hp infection is associated with an increased incidence of precancerous changes in the gastric mucosa. Nevertheless, precancerous changes are not observed in every Hp-infected individual, suggesting that environmental and genetic factors may also play a role in the formation and appearance of precancerous lesions. In the present study, the association between polymorphisms in the promoter regions of human myeloperoxidase (MPO -463G--> A) and catalase (CAT -262C-->T) genes and the appearance of precancerous changes in the gastric mucosa of our patient population were examined. Patients enrolled in this study were undergoing endoscopy for gastrointestinal complaints. Samples were collected from 126 patients at Kings County Hospital in Brooklyn and St. John's Episcopal Hospital in Queens. One antral biopsy was taken for genotyping, while additional biopsies were taken from the antrum and fundic region for histological analysis and were scored with respect to acute and chronic inflammation, GA, IM and Hp infestation according to the Sydney classification. MPO and CAT genotypes were determined by PCR and RFLP. CAT genotypes did not influence the incidence or severity of precancerous lesions in the fundic or antral regions of the stomach, whereas the MPO -463A allele was associated with an increase in intensity of gastric atrophy in the fundic mucosa. In Hp-infected individuals, the MPO -463G/G genotype was associated with an increase in the incidence of IM in the antrum, whereas the A allele was associated with an increase in IM in the fundic region. These paradoxical findings suggest that different MPO genotypes are associated with the appearance of IM in distinct anatomical regions of the stomach. However, since the majority of gastric cancer (GC) cases in our patient population occurred in the antrum, the MPO -463G/G genotype, which is associated with increased MPO expression and antral IM, may be considered a risk factor for GC.

Intracellular, intercellular, and stromal invasion of gastric mucosa, preneoplastic lesions, and cancer by Helicobacter pylori

BACKGROUND AND AIMS

It is not clear how Helicobacter pylori, an apparently extracellular pathogen colonizing the luminal side of the gastric epithelium, invariably causes an immune-inflammatory response on the stromal side of the mucosa. Penetration of H pylori into epithelial cell lines and its interaction with immune-inflammatory cells have been documented in vitro. Several investigations also showed in vivo bacterial penetration into the epithelium up to the lamina propria; however, the identification as H pylori of the bacteria-like bodies observed in unchanged, metaplastic, or neoplastic mucosa remained sometimes questionable.

METHODS

To search for bacteria-like organisms, we used transmission electron microscopy on endoscopic biopsy specimens from 20 dyspeptic subjects and surgical specimens of neoplastic and nonneoplastic mucosa from 20 cancerous stomachs. To ascertain the H pylori nature of the organisms found, we used 6 different antibodies directed against bacterial lysates, purified vacuolating cytotoxin A, or purified cytotoxin-associated antigen A in immunogold tests. The results were compared with those of H pylori strains cultivated in vitro.

RESULTS

In nonmetaplastic gastric epithelium, cytochemically proven H pylori were detected, in the majority of cases, inside cytoplasm of epithelial cells, in intraepithelial intercellular spaces, and in underlying lamina propria, often in direct contact with immune-inflammatory cells and sometimes inside small blood vessels. Cytochemically proven H pylori were also observed inside 6 of 8 intestinal metaplasias and 9 of 20 cancers.

CONCLUSIONS

H pylori penetrates normal, metaplastic, and neoplastic gastric epithelium in vivo, intracellularly, or interstitially to cause a strong immune-inflammatory response and promote gastric carcinogenesis.

Intestinal microbiota: a potential diet-responsive prevention target in ApcMin mice

We previously reported that two dietary regimens, calorie restriction (CR) and a high olive oil-containing diet supplemented with a freeze-dried fruit and vegetable extract (OFV), reduced the development of intestinal adenomas in Apc(Min) mice by 57% and 33%, respectively, compared to control mice fed a defined diet ad libitum. The OFV diet was designed to have a strong effect on the composition of the intestinal microbiota through its high content of fiber, which represents a major source of fermentable substrate for the gut bacteria. We hypothesized that some of the observed effects of diet on intestinal carcinogenesis might be mediated by diet-related changes in the bacterial species that thrive in the gut. Therefore, we determined by fluorescent in situ hybridization (FISH) and denaturing gradient gel electrophoresis (DGGE) how the dietary interventions affected the composition of the intestinal microbiota, and we characterized specific microbiota changes that were associated with diet and reduced intestinal carcinogenesis. The OFV diet changed the overall composition of the intestinal microbiota, smaller changes were observed for the CR diet. Furthermore, we detected a 16S rDNA fragment associated with mice that did not develop polyps. Sequence analysis suggested that hitherto unidentified bacteria belonging to the family Lachnospiraceae (order Clostridiales) were its source. Thus, these bacteria may be an indicator of intestinal conditions associated with reduced intestinal carcinogenesis in Apc(Min) mice.

Innate Immune Inflammatory Response against Enteric Bacteria Helicobacter hepaticus Induces Mammary Adenocarcinoma in Mice

Inflammation associated with bacterial infections is a risk factor for cancers in humans, yet its role in breast cancer remains poorly understood. We have previously shown that innate immune inflammatory response against intestinal bacteria is sufficient to induce colon cancer. Here we report that infecting Rag2-deficient C57BL/6 Apc(Min/+) mice with an intestinal bacterial pathogen, Helicobacter hepaticus, significantly promotes mammary carcinoma in females and enhances intestinal adenoma multiplicity by a tumor necrosis factor alpha (TNFalpha)-dependent mechanism. The mammary and intestinal tumor development as well as the increase in proinflammatory mediators is suppressed by adoptive transfer of interleukin 10-competent CD4+CD45RB(lo)CD25+ regulatory (T(R)) cells. Furthermore, prior exposure of donor mice to H. hepaticus significantly enhances antitumor potency of their T(R) cells. Interestingly, these microbially experienced T(R) cells suppress tumorigenesis more effectively in recipient mice irrespective of their tumor etiology. These data suggest that infections with enteric pathogens enhance T(R)-cell potency and protect against epithelial cancers later in life, potentially explaining paradoxical increases in cancer risk in developed countries having more stringent hygiene practices. The possibility that dysregulated gut microbial infections in humans may lead to cancer in anatomically distant organs, such as breast, highlights the need for novel immune-based strategies in cancer prevention and treatment.

Helicobacter pylori induces gastritis and intestinal metaplasia but no gastric adenocarcinoma in Mongolian gerbils

OBJECTIVE

The Mongolian gerbil is considered as the model of choice when studying adenocarcinoma related to Helicobacter pylori infection. The purpose of this study was to compare two different H. pylori strains and elucidate whether adenocarcinomas developed in gerbils.

MATERIAL AND METHODS

Male gerbils were separated into three groups: one control and two groups infected with two different strains of H. pylori, TN2GF4 and SS1. At 3, 6, 12 or 18 months after inoculation 5 animals from each group were sacrificed. The stomach was used for culture, and for histology.

RESULTS

Inflammation was seen after 3 months in all the infected animals. In the controls no pathology was found at any time. Intestinal metaplasia was found in both the infected groups. Glands buried in the submucusal layer, changes that might be misinterpreted as adenocarcinoma, were found in 10% of the SS1 and in 65% of the TN2GF4 animals. Adenocarcinoma was not found in any of the gerbils.

CONCLUSIONS

All studies claiming to have found H. pylori-induced adenocarcinomas in gerbils describe atypical glands penetrating into the muscularis propria and interpret these as invasive growths due to cancer. An alternative interpretation is that the deranged glandular structures grow in and below the submucosa. It is suggested that atypical glands in the muscularis layer are not enough as a diagnostic criterion for gastric adenocarcinoma. It is concluded that adenocarcinoma has not yet been shown convincingly to develop in Mongolian gerbils infected with H. pylori. Nevertheless, it is a model well suited for studying gastritis, gastric ulcer and premalignant changes such as metaplasia.

Dual infection with Helicobacter bilis and Helicobacter hepaticus in p-glycoprotein-deficient mdr1a-/- mice results in colitis that progresses to dysplasia

Patients with inflammatory bowel disease (IBD) are at increased risk for developing high-grade dysplasia and colorectal cancer. Animal IBD models that develop dysplasia and neoplasia may help elucidate the link between inflammation and colorectal cancer. Mdr1a-/- mice lack the membrane efflux pump p-glycoprotein and spontaneously develop IBD that can be modulated by infection with Helicobacter sp: H. bilis accelerates development of colitis while H. hepaticus delays disease. In this study, we determined if H. hepaticus infection could prevent H. bilis-induced colitis. Unexpectedly, a proportion of dual-infected mdr1a-/- mice showed IBD with foci of low- to high-grade dysplasia. A group of dual-infected mdr1a-/- animals were maintained long term (39 weeks) by intermittent feeding of medicated wafers to model chronic and relapsing disease. These mice showed a higher frequency of high-grade crypt dysplasia, including invasive adenocarcinoma, possibly because H. hepaticus, in delaying the development of colitis, allows time for transformation of epithelial cells. Colonic epithelial preparations from co-infected mice showed increased expression of c-myc (5- to 12-fold) and interleukin-1alpha/beta (600-fold) by real-time polymerase chain reaction relative to uninfected wild-type and mdr1a-/- animals. This animal model may have particular relevance to human IBD and colorectal cancer because certain human MDR1 polymorphisms have been linked to ulcerative colitis and increased risk for colorectal cancer.

Interleukin-8 response in an intestinal HCT-8 cell line infected with enteroaggregative and enterotoxigenic Escherichia coli

This study examined the interleukin-8 (IL-8) response of the intestinal adenocarcinoma HCT-8 cell line to infection with enteroaggregative and enterotoxigenic Escherichia coli pathotypes isolated from patients with travelers' diarrhea. Individual diarrheagenic E. coli strains (enteroaggregative E. coli [EAEC]; n = 30), heat-stable enterotoxin (ST)-producing enterotoxigenic E. coli (ETEC ST; n = 11), heat-labile enterotoxin (LT)-producing enterotoxigenic E. coli (ETEC LT; n = 10), and ST- and LT-producing enterotoxigenic E. coli (ETEC ST:LT; n = 8) were coincubated with HCT-8 cells for 3 h. Tissue culture supernatants were assayed for IL-8 content by enzyme-linked immunosorbent assay. Fifty percent of EAEC (72% of those EAEC carrying the virulence factors aggR, aggA, and aspU and 40% of those EAEC not carrying virulence factors) and 64% of ETEC ST elicited IL-8 production. In contrast, 10% of ETEC LT elicited the production of IL-8 above baseline. These results suggest that (i) the HCT-8 cell line infection model can be used as a tool to differentiate proinflammatory E. coli from noninflammatory isolates; (ii) EAEC has a heterogeneous ability to induce the production of IL-8, and this may be associated with the presence of virulence factors; and (iii) ETEC ST can elicit an inflammatory response and helps explain our earlier findings of increased fecal IL-8 in patients with ETEC diarrhea.

[Proliferation and apoptosis in primary gastrointestinal B-cell non-Hodgkin s lymphoma and its association with Helicobacter pylori]

OBJECTIVE

To investigate primary gastrointestinal B-cell non-Hodgkin s lymphoma for clinicopathological features, proliferation, apoptosis and its association with Helicobacter pylori (HP).

METHODS

Classification of tumors, expression of HP, proliferation and apoptosis related gene products were studied by immunohistochemistry. Apoptosis was studied by TUNEL (TdT [terminal deoxynucleotidyl transferase] dUTP nick end-labeling).

RESULTS

There were 15 cases of mucosa associated lymphoid tissue (MALT) lymphoma (9 in stomach, 6 in intestine) and 42 cases of diffuse large B cell lymphoma (DLBCL) (28 in stomach, 14 in intestine) in all the 57 cases of primary gastrointestinal BCL. The average apoptotic indexes (AI) were 0.16%, 2.54% in MALT lymphoma and DLBCL respectively. The average proliferation indexes (PI) were 2.22% and 8.71%,respectively. The p53 positive rates were 6.7% and 35.7%. PI (P=0.026) and p53 (P=0.044) had significant differences; But Bcl-2 positive rates were 60.0% and 35.7%,and HP positive rates were 66.7% and 23.8%, respectively. HP had significant differences (P=0.005).

CONCLUSION

HP and gastrointestinal MALT lymphoma had significant relation. Apoptosis and proliferative activity were higher in DLBCL than in MALT. The higher Bcl-2 expression in MALT may be related to lower apoptosis. p53 promotes apoptosis and p53 gene mutation may play a role in the progression from MALT to DLBCL. HP antibody may be used in HP detection in gastrointestinal BCL.

Bacteria-induced intestinal cancer in mice with disrupted Gpx1 and Gpx2 genes

Two glutathione peroxidase (GPX) isozymes, GPX-1 and GPX-2 (GPX-GI), are the major enzymes that reduce hydroperoxides in intestinal epithelium. We have previously demonstrated that targeted disruption of both the Gpx1 and Gpx2 genes (GPX-DKO) results in a high incidence of ileocolitis in mice raised under conventional conditions, which include the harboring of Helicobacter species [non-specific-pathogen-free (non-SPF) conditions]. In this study, we have characterized GPX-DKO mice that have microflora-associated intestinal cancers, which are correlated with increased intestinal pathology/inflammation. We found that GPX-DKO mice raised under germ-free conditions have virtually no pathology or tumors. After colonizing germ-free mice with commensal microflora without any known pathogens (SPF), <9% of GPX-DKO mice develop tumors in the ileum or the colon. However, about one-fourth of GPX-DKO mice raised under non-SPF conditions from birth or transferred from SPF conditions at weaning have predominantly ileal tumors. Nearly 30% of tumors are cancerous; most are invasive adenocarcinomas and a few signet-ring cell carcinomas. On the basis of these results, we conclude that GPX-DKO mice are highly susceptible to bacteria-associated inflammation and cancer. The sensitivity exhibited in these mice suggests that peroxidative stress plays an important role in ileal and colonic pathology and inflammation, which can lead to tumorigenesis.

[Immunostimulating and anti-carcinogenic activity of the normal intestinal lactoflora]

One of major functions of lactic acid bacteria is their participation in the formation of local and systemic immune resistance of the host. The lactic acid bacteria associated with the mucous coat of the gastro-intestinal tract are cooperating with epitheliocytes, M-cells of Peyer's patches and various cells of the immune system. As a result of processing and presentation of specific cell components, lactic acid bacteria use mechanisms of modulation of cell-dependent immune response, activate RES and stimulate cytokine production. The article gives data on the role of lactic acid bacteria in the formation of T-and B-cell immune response, production of pro-inflammatory and anti-inflammatory cytokines ensuring the balance between humoral and cell-dependent immunity. The mechanisms of antitumor and oncostatic activity of lactic acid bacteria are analyzed. The polyfunctional influence of lactic acid bacteria on the immune reactions of the macroorganism includes the enhancement of the activity of monocyto-macrophages, natural killers and cytotoxic lymphocytes, modulation of reactions of the T- and B-cell immune responses, i.e. the complex system of interaction being formed between the indigenous intestinal microflora and the macroorganism is the basis of the normal function of its immune system.

Higher gastric cycloxygenase-2 expression and precancerous change in Helicobacter pylori-infected relatives of gastric cancer patients

PURPOSE

This study was conducted to determine whether relatives of gastric cancer patients (GCF) showed greater gastric cycloxygenase-2 (COX-2) expression or a greater incidence of precancerous lesions after Helicobacter pylori infection and whether H. pylori eradication could reduce COX-2 expression.

EXPERIMENTAL DESIGN

Three hundred subjects were enrolled in this study: half were relatives of 50 H. pylori-infected gastric cancer patients, and half were relatives of 50 H. pylori-infected duodenal ulcer (DU) patients (controls). Each relative underwent endoscopy to detect H. pylori infection and related gastric histology. One hundred and twenty GCFs were found to have H. pylori infection. After H. pylori eradication, 90 of the 120 GCFs were followed up with annual endoscopy examinations over the next 2 years. Gastric COX-2 intensity in all of the specimens collected from these patients was immunochemically stained and graded from 0 to 4.

RESULTS

H. pylori infection, gastric atrophy, and intestinal metaplasia (IM) were more prevalent in GCFs than in relatives of H. pylori-infected patients with DUs (P < 0.05). H. pylori-infected GCFs also showed a greater COX-2 intensity than H. pylori-infected relatives of patients with DUs (89.1% versus 62.7%, P < 0.001; relative risk: 4.9; 95% confidence interval: approximately 2.34-10.29). Among the H. pylori-infected GCFs, COX-2 intensity correlated with atrophy and IM (P < 0.001). After H. pylori eradication, gastric COX-2 expression disappeared only in those relatives without IM (P < 0.001).

CONCLUSIONS

GCFs are more likely to show greater gastric COX-2 expression and a higher incidence of precancerous lesions after H. pylori infection than the relatives of H. pylori-infected patients with only DUs. H. pylori eradication can reverse gastric COX-2 expression in patients without IM but not in patients with IM.

Plasma enterolactone or intestinal Bifidobacterium levels do not explain adenoma formation in multiple intestinal neoplasia (Min) mice fed with two different types of rye-bran fractions

The study was designed to evaluate whether two types of rye-bran fractions result in distinct bifidogenic effect or enterolactone production in multiple intestinal neoplasia (Min) mice and whether these parameters are associated with intestinal tumorigenesis in this animal model. The experimental diets were a non-fibre diet (control), a rye-bran diet, and diets containing either the soluble extract or the insoluble fraction prepared from rye bran. The main result on adenoma formation in these experiments was the observation that the soluble extract increased number (P=0.012) and size (P=0.008) of adenomas in the distal small intestine when compared with the non-fibre group. All rye-supplemented diets supported similarly the in vivo growth of Bifidobacterium (10(8)-10(9) colony forming units/g) in Min mice, whereas the non-fibre diet lowered intestinal Bifidobacterium below the level of detection. The results show that water solubility does not affect the bifidogenicity of rye bran. Mean plasma enterolactone concentration was highest in the rye-bran group (30.0 nmol/l; P=0.002), which along with the soluble-extract group (16.2 nmol/l; P=0.024) differed significantly from the non-fibre diet group (7.5 nmol/l). Thus, the mice fed with the rye bran were the best enterolactone producers. In conclusion, rye bran and rye fractions influence adenoma formation in Min mice to a varying degree but plasma enterolactone levels or the production of bifidogenic bacteria do not mediate the effect.

Oral yeast carriage in patients with advanced cancer

The aim of this study was to investigate oral yeast carriage amongst patients with advanced cancer. Oral rinse samples were obtained from 120 subjects. Yeasts were isolated using Sabouraud's dextrose agar and CHROMagar Candida, and were identified using a combination of the API 20 C AUX yeast identification system, species-specific PCR and 26S rDNA gene sequencing. Oral yeast carriage was present in 66% of subjects. The frequency of isolation of individual species was: Candida albicans, 46%; Candida glabrata, 18%; Candida dubliniensis, 5%; others, < 5%. The increasing isolation of non-Candida albicans species is clinically important, since these species are often more resistant to antifungal drugs. Oral yeast carriage was associated with denture wearing (P = 0.006), and low stimulated whole salivary flow rate (P = 0.009). Identification of these risk factors offers new strategies for the prevention of oral candidosis in this group of patients.

Prevalence of subtypes of intestinal metaplasia in the general population and in patients with autoimmune chronic atrophic gastritis

BACKGROUND

Gastric intestinal metaplasia (IM) is seen mostly in association with chronic gastritis, induced either by Helicobacter pylori infection or autoimmune mechanisms. IM can be categorized into three subtypes, where type III is associated with gastric carcinoma of intestinal type.

METHODS

Gastric biopsies from 475 subjects randomly selected from the general population and from 27 patients with autoimmune gastritis associated with pernicious anaemia were used. The criteria of Filipe & Jass were applied using different histochemical techniques in combination with haematoxylin and eosin stained material.

RESULTS

Twenty-three percent (109/475) of the subjects from the general population and 88% (24/27) in the group with autoimmune gastritis had IM. Type III IM occurred in 4% in both populations. Type III IM was located in the antrum in 90% in the general population. In the group with autoimmune gastritis, only one patient had type III IM, which was located in the corpus.

CONCLUSIONS

This study reveals for the first time the prevalence and distribution of subtypes of IM in a general population from the Western world. The comparatively high prevalence of type III IM in the general population (4%) indicates that its role as a precursor of gastric carcinoma may have been overemphasized. A similar prevalence of type III IM in patients with autoimmune gastritis may be considered low and suggests that mechanisms for gastric carcinogenesis other than the atrophy-metaplasia-dysplasia sequence could also operate in this condition.

Pathological disorders of the gastric mucosa surrounding carcinomas and primary lymphomas

OBJECTIVE

Gastritis, intestinal metaplasia, atrophy, and dysplasia are disorders that frequently precede the full development of gastric adenocarcinoma. On the other hand, primary gastric lymphomas seem to arise from mucosa-associated lymphoid tissue. It is well accepted that these histological changes are caused by Helicobacter pylori infection. The objective of this study is to determine the frequency and characteristics of epithelial and lymphoid tissue disorders of the gastric mucosa surrounding primary carcinomas and lymphomas.

METHODS

We studied 111 gastrectomies from patients harboring primary adenocarcinomas (30 intestinal and 30 diffuse type) and 51 gastric lymphomas. For comparative purposes, we analized 86 stomachs from patients who died of diseases other than gastric malignancies. Histopathological disorders of the gastric mucosa adjacent to primary neoplasms such as atrophy, intestinal metaplasia, and dysplasia were recorded. Lymphoid follicles were classified in two groups, with or without expansion. Expansion was characterized by increased size, irregular borders, enlarged marginal zone, and expanded germinal centers. Differences were statistically evaluated with chi2 and Fisher exact tests, odds ratio, and relative risk, with 95% CI. p values <0.05 were considered statistically significant.

RESULTS

Most intestinal-type adenocarcinomas showed atrophy (76.6%) and intestinal metaplasia (86.6%) and less frequently, dysplasia (23.3%), in the surrounding gastric mucosa. Expansive lymphoid follicles were more frequent among lymphomas than in adenocarcinomas (56.8% vs 25%); however, a high percentage of lymphomas were also associated with atrophy (50.9%), intestinal metaplasia (62.7%), and rarely dysplasia (11.8%). On the contrary, diffuse-type adenocarcinoma displayed less frequently atrophy (33%), intestinal metaplasia (50%), and dysplasia (3%). Gastric mucosa from patients without any gastric neoplasia was almost normal (84%), whereas the remaining 16% showed, both or alone, atrophy and intestinal metaplasia.

CONCLUSION

Histopathological disorders of the gastric mucosa are not specific for any neoplasm, but intestinal-type adenocarcinomas frequently showed atrophy, intestinal metaplasia, and not uncommonly, dysplasia of the surrounding non-neoplastic gastric mucosa. Diffuse-type adenocarcinomas did not frequently show such lesions. Primary lymphomas displayed expansive lymphoid follicles and also a high percentage of atrophy and intestinal metaplasia of the surrounding gastric mucosa. The presence of intestinal metaplasia, atrophy, and lymphoid follicles with expansion in endoscopic biopsies could suggest a higher suceptibility for the development of gastric intestinal-type adenocarcinoma or gastric lymphoma. Patients harboring such histopathological changes must receive eradication therapy against H. pylori and probably closer follow-up.

[Detection of Helicobacter pylori in tissue samples of stomach cancer]

The role of Helicobacter pylori in the carcinogenesis of the stomach has been recognised both in intestinal and diffuse forms. The occurrence of the bacterium was studied in this report, with various methods in biopsy samples from the cancerous stomach, as well as the presence of associated gastritis and metaplasia related to the histological type. Retrospective histological examination were performed on endoscopic biopsy samples from 124 patients with distal stomach cancer using haematoxillin-eosin and Giemsa staining and immunohistochemical tests. Out of the 124 samples 69 (55.64%) was positive: 48 with Giemsa staining and further 21 samples showed immunohistochemical positivity on atrophic gastritis samples despite negative Giemsa staining. In view of the presence of gastritis and metaplasia significant difference (p < 0.001) was found between the positive and negative cases. The ratio of the Helicobacter pylori positive samples was high both for intestinal and diffuse type carcinomas. Our results suggest that the presence of Helicobacter pylori infection is important in the development of both types of carcinoma, nevertheless, the hystological type of the tumor is also decisively influenced by the onset of action of other more direct local eliciting factors.

Inhibitory effect of intestinal bacteria on spontaneous multiple polyps in the small intestine of gnotobiotic BALB/c mice

The incidence of multiple polyps and number of polyps per mouse were significantly lower in conventionalized (CVz), and chloroform-resistant bacteria (CRB)- or fusiform bacteria (FB)-associated mice than in germfree (GF) BALB/c mice. The concentration of fecal fatty acids was also higher in mice associated with either CRB or FB than in GF mice. The incidence of multiple polyps and number of polyps per mouse were significantly correlated with the concentration of fatty acids in the feces of CVz and CRB-GB mice. This study demonstrated that inhibition of multiple polyps in the small intestine of BALB/c mice was affected by the production of intestinal fatty acids.

Primary intestinal non-Hodgkin's lymphoma and Epstein-Barr virus: high frequency of EBV-infection in T-cell lymphomas of Mexican origin

Epstein-Barr virus is universally associated with endemic Burkitt's lymphoma (BL) and undifferentiated nasopharyngeal carcinoma and can be detected in a significant proportion of cases of Hodgkin's disease (HD) and peripheral T-cell lymphoma, but only rarely in sporadic B-NHL. The frequency of EBV-positivity in certain neoplasms shows important geographic variations. Both HD and sporadic BL from Latin America have shown higher rates of EBV-association than cases from Western countries. In T-NHL, the frequency of EBV-positivity is influenced by the site of the primary tumor and the phenotype of the neoplastic cells. Nasal and nasal-type T-NHL, which show a T/NK-cell phenotype with expression of CD56 are virtually always EBV-associated, whereas only a proportion of nodal, gastrointestinal and pulmonary T-NHL are EBV-infected. A recent investigation of primary intestinal lymphomas of Mexican origin demonstrated EBV-positivity in all examined cases of T-NHL and BL and a proportion of other B-NHLs. The presence of EBV was independent of the presence or absence of enteropathy. Two of 6 cases studied showed CD56 expression. The high rate of EBV-positivity independent of histologic subtype is in contrast to the low to intermediate rates of EBV-positivity found in cases of intestinal T-NHL from Western countries and indicates that geographic differences in the frequency of EBV-association of lymphoid neoplasms might also extend to a fraction of peripheral T-cell lymphomas.

Helicobacter pylori infection and the risk of gastric cancer among the Korean population

Helicobacter pylori infection has been associated with chronic atrophic gastritis, a precursor of gastric cancer. We conducted a prospective, case-controlled study to investigate whether H. pylori infection increases the risk of gastric cancer in Korean people with a high risk of gastric cancer. We enrolled 160 gastric cancer patients who were confirmed by endoscopic biopsy during 1994 and 160 age-matched control subjects with non-ulcer dyspepsia were compared to document the relationship between H. pylori infection and gastric cancer. The presence of H. pylori infection was determined by the rapid urease test and/or histology by Wright-Giemsa staining. The overall presence of H. pylori infection was 60% in gastric cancer patients and 51.9% in age-matched control subjects (odds ratio 1.39; 95% confidence interval 0.894-2.17; P = 0.143). Carcinomas of cardia, body and antrum were not associated with H. pylori infection (odds ratio 1.43, 1.69 and 1.29, respectively; 95% confidence interval, 0.271-7.52, 0.787-3.62 and 0.689-2.43, respectively; P = 0.178, 0.177 and 0.642, respectively) nor was the intestinal or diffuse type of cancer (odds ratio 1.39 and 1.40, respectively; 95% confidence interval 0.791-2.45 and 0.681-2.87, respectively; P = 0.250 and 0.835, respectively). Gender was not a risk for gastric cancer. In contrast to previous studies, these results do not provide evidence of H. pylori infection for gastric carcinogenesis in Korea.

Adenomatous intestinal hyperplasia in guinea pigs associated with Campylobacter-like bacteria

Adenomatous intestinal hyperplasia was diagnosed in two dams and five young guinea pigs. The pathological condition was characterized by diarrhea and the thickened, rugose jejunum and ileum. Adenomatous proliferation of immature crypt epithelial cells was observed primarily in the ileum and the distal part of the jejunum. Immature epithelial cells contained various numbers of intracytoplasmic, non-membrane bound, curved organisms resembling Campylobacter sp. bacteria.

Promoting effect of intestinal Pseudomonas aeruginosa on gastric tumorigenesis in rats with N-methyl-N'-nitro-N-nitrosoguanidine

The effect of Pseudomonas aeruginosa colonizing in the gut on the development of gastrointestinal tumors was studied in rats treated orally with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). The animals were inoculated with or accidentally colonized by P. aeruginosa after MNNG treatment. In 3 serial experiments, P. aeruginosa-positive, MNNG-treated rats consistently showed a significantly higher incidence of gastric tumors than P. aeruginosa-negative, MNNG-treated animals. The total incidence of gastric tumors was 40% (34/86) in the former, and only 11% (7/61) in the latter. The development of tumors in the small intestine was not likely to be influenced by P. aeruginosa colonization. It is concluded that P. aeruginosa in the gut plays a promoting role in gastric tumorigenesis in rats orally administered with MNNG.

Growth in culture of adenocarcinoma cells from the small intestine of sheep

Explant cultures were initiated from adenocarcinoma of the small intestine in sheep and from various metastases. Several cell types grew, most being fibroblastic in nature. However, 2 cultures yielded mixed cells which arranged themselves into areas of epithelial-like cells surrounded by fibroblast-like cells and this pattern was consistent over 30 subcultures and several months of culturing. The epithelial-like cells were separated from the others by the use of a modified medium containing citrulline or by sedimentation through a bovine serum albumin solution. Various properties, including their growth rate in 5% and 0.5% serum, the absence of surface fibronectin and their ability to grow in semi-solid agar, indicated that they may represent carcinoma cells. Screening for virus production from these cells and all other explant cultures proved negative.

Rat ileocecal immunocytoma. An ultrastructural study with special attention to the presence of viral particles

Fifteen spontaneous immunocytomas originating in the ileocecal lymph nodes of Lou/C/Wsl rats were studied by means of electron microscopy. The histology was characteristic, the tumor being formed by an accumulation of large, rounded cells with slightly eccentric ovoid nuclei, large nucleoli, and finely condensed chromatin along the nuclear walls; the cytoplasma was rich in polyribosomes. The appearance of the rough endoplasmic reticulum was apparently the same whether or not the tumor was secretory. Its development varied from one cell to another, and in only a small proportion of cells did it attain any considerable volume. In all the tumors examined, we noted the presence of intracisternal A-particles. In its morphology, the rat immunocytoma resembled the plasmacytomas induced in mice, and it also resembled certain human tumors such as Burkitt's lymphoma.

Porcine intestinal adenomatosis associated with serologically distinct Campylobacter sputorum subspecies mucosalis

A variant of Campylobacter sputorum subspecies mucosalis which is serologically distinct from all strains previously examined is described. It has been isolated from cases of porcine intestinal adenomatosis and necrotic enteritis and in all other characteristics conforms to the description of mucosalis.

Endotoxin and bacteria in portal blood

In order to determine whether endotoxin is normally found in the portal system, intraoperative samples of portal and peripheral blood were drawn from 34 consecutive elective abdominal surgery patients. The limulus lysate test was used to detect endotoxin. Ninety-seven per cent of patients had a positive limulus test in portal blood. Twelve of these patients were tested for portal bacteremia and only one showed growth. Four patients also had systemic endotoxemia. Three of these had liver disease and one had a gram-negative sepsis. This study demonstrates that endotoxin is a normal constituent of portal venous blood in man and does not represent a pathological process. It is suggested that the Kupffer cells of the liver normally protect the systemic circulation from endotoxin, and that endotoxin is present in systemic blood only when liver function is impaired or gram-negative bacteremia is present.

Diet and metabolism: large-bowel cancer

Epidemiological data demonstrate that colon cancer incidence is associated mainly with high dietary fat consumption. Studies in metabolic epidemiology indicate that high fat intake influences both the amount and type of bile acids and neutral sterols and intestinal microflora acting on these compounds which may contain tumorigenic activity for the colon. This is compatible with the results of studies comparing populations with high or low risk for the colon cancer and patients with colon cancer.

Studies on Campylobacter sputorum subspecies Mucosalis

Catalase-negative vibrios can be isolated in large numbers from the affected intestinal mucosa of pigs suffering from a range of porcine enteropathies in which the mucosa has an adenomatous component. These vibrios cannot be distinguished from strains of Campylobacter sputorum subsp. mucosalis. The resemblance between these bacteria strengthens the case already made on morphological evidence that these enteropathies have a common origin. Catalase-negative vibrios have also been isolated from the mouth and faeces of pigs. Some of these conform to the criteria established for the mucosalis subspecies but others can be differentiated from it. An antigenic analysis shows that strains of the mucosalis subspecies are closely related antigenically, but that differences may allow separation of strains.

Further leads on metabolic epidemiology of large bowel cancer

Studies in metabolic epidemiology have shown that the dietary intake of high fat affects the composition of the intestinal bacteria and their metabolic activity as well as the levels of certain neutral sterols and bile acids that may act as tumor promoters for the colon. A strong association has also been established between microbially modified bile acids and cholesterol metabolites and the risk of colon cancer among different populations. The patients with colon cancer had high concentrations of fecal bile acids and cholesterol metabolites compared with the controls. It remains to be shown whether this established association is causative in nature.

Intestinal adenomatosis in the pig: a possible relationship with a haemorrhagic enteropathy

An outbreak of a haemorrhagic enteropathy in a closed herd of pigs was followed by the appearance, in the same herd, of cases of intestinal adenomatosis. This paper now draws attention to similarties in the mucosal pathology which are present in the two conditions. The affected tissue showed substantial epithelial proliferation and retrospective electron microscopic studies of material from both these entities revealed the presence of bacteria of similar morphology within the cytoplasm of these epithelial cells.