Alteration of local microflora and α-defensins hyper-production in colonic adenoma mucosa

The presence of bacteria varies between colorectal adenocarcinomas, precursor lesions and non-malignant tissue

BACKGROUND

A causal association has been suggested between certain bacteria and colorectal cancer (CRC). Only a few studies have, however, investigated the presence of these bacteria directly in colon tissue with conflicting results. It is thus uncertain which role they may have in prognosis and carcinogenesis of CRC.

METHODS

Formalin-fixed and paraffin-embedded (FFPE) colorectal tissue samples from patients diagnosed with colorectal cancer (CRC)(tumor and paired normal tissue, n = 99), adenomas (n = 96), or diverticular disease (n = 104) were tested for the presence and bacterial load of Streptococcus gallolyticus (S. gallolyticus), Fusobacterium nucleatum (F. nucleatum), and Bacteroides fragilis (B. fragilis) using quantitative PCR. A subsequent broader search was conducted on a subset of samples using 16S ribosomal RNA gene sequencing. Finally, to evaluate the prognostic value, the bacterial status was compared to patient outcome.

RESULTS

S. gallolyticus was not detected by qPCR in any of the investigated tissue samples and F. nucleatum and B. fragilis were found to be equally distributed in tumors, paired normal tissue, and diverticula, but significantly less present in adenomas compared to both tumors and diverticula. Neither, F. nucleatum nor B. fragilis status affected the five-year prognosis of the patients. The 16S rRNA gene sequencing data revealed that tumors were associated with the Prevotella genus while conversely adenomas and diverticula were associated with Acinetobacter genus.

CONCLUSION

These findings do not support a role of F. nucleatum or B. fragilis during colorectal beginning, while S. gallolyticus was not implicated in the colorectal tissue of a Danish population. A potential role of the bacterial genera Prevotella and Acinetobacter was indicated, and requires further investigations.

Mucosal adhesion and anti-inflammatory effects of Lactobacillus rhamnosus GG in the human colonic mucosa: A proof-of-concept study

AIM

To investigate the adhesion and anti-inflammatory effects of Lactobacillus rhamnosus GG (LGG) in the colonic mucosa of healthy and ulcerative colitis (UC) patients, both in vivo and ex vivo in an organ culture model.

METHODS

For the ex vivo experiment, a total of 98 patients (68 UC patients and 30 normal subjects) were included. Endoscopic biopsies were collected and incubated with and without LGG or LGG-conditioned media to evaluate the mucosal adhesion and anti-inflammatory effects [reduction of tumor necrosis factor alpha (TNFα) and interleukin (IL)-17 expression] of the bacteria, and extraction of DNA and RNA for quantification by real-time (RT)-PCR occurred after the incubation. A dose-response study was performed by incubating biopsies at “regular”, double and 5 times higher doses of LGG. For the in vivo experiment, a total of 42 patients (20 UC patients and 22 normal controls) were included. Biopsies were taken from the colons of normal subjects who consumed a commercial formulation of LGG for 7 d prior to the colonoscopy, and the adhesion of the bacteria to the colonic mucosa was evaluated by RT-PCR and compared with that of control biopsies from patients who did not consume the formulation. LGG adhesion and TNFα and IL-17 expression were compared between UC patients who consumed a regular or double dose of LGG supplementation prior to colonoscopy.

RESULTS

In the ex vivo experiment, LGG showed consistent adhesion to the distal and proximal colon in normal subjects and UC patients, with a trend towards higher concentrations in the distal colon, and in UC patients, adhesion was similar in biopsies with active and quiescent inflammation. In addition, bioptic samples from UC patients incubated with LGG conditioned media (CM) showed reduced expression of TNFα and IL-17 compared with the corresponding expression in controls (P < 0.05). Incubation with a double dose of LGG increased mucosal adhesion and the anti-inflammatory effects (P < 0.05). In the in vivo experiment, LGG was detectable only in the colon of patients who consumed the LGG formulation, and bowel cleansing did not affect LGG adhesion. UC patients who consumed the double LGG dose had increased mucosal concentrations of the bacteria and reduced TNFα and IL-17 expression compared with patients who consumed the regular dose (48% and 40% reduction, respectively, P < 0.05).

CONCLUSION

In an ex vivo organ culture model, LGG showed consistent adhesion and anti-inflammatory effects. Colonization by LGG after consumption for a week was demonstrated in vivo in the human colon. Increasing the administered dose increased the adhesion and effectiveness of the bacteria. For the first time, we demonstrated that LGG effectively adheres to the colonic mucosa and exerts anti-inflammatory effects, both ex vivo and in vivo.

Folic Acid and Vitamin B12 Supplementation and the Risk of Cancer: Long-term Follow-up of the B Vitamins for the Prevention of Osteoporotic Fractures (B-PROOF) Trial

BACKGROUND

Folic acid and vitamin B12 play key roles in one-carbon metabolism. Disruption of one-carbon metabolism may be involved in the risk of cancer. Our aim was to assess the long-term effect of supplementation with both folic acid and vitamin B12 on the incidence of overall cancer and on colorectal cancer in the B Vitamins for the Prevention of Osteoporotic Fractures (B-PROOF) trial.

METHODS

Long-term follow-up of B-PROOF trial participants (N = 2,524), a multicenter, double-blind randomized placebo-controlled trial designed to assess the effect of 2 to 3 years daily supplementation with folic acid (400 μg) and vitamin B12 (500 μg) versus placebo on fracture incidence. Information on cancer incidence was obtained from the Netherlands cancer registry (Integraal Kankercentrum Nederland), using the International Statistical Classification of Disease (ICD-10) codes C00-C97 for all cancers (except C44 for skin cancer), and C18-C20 for colorectal cancer.

RESULTS

Allocation to B vitamins was associated with a higher risk of overall cancer [171 (13.6%) vs. 143 (11.3%); HR 1.25; 95% confidence interval (CI), 1.00-1.53, P = 0.05]. B vitamins were significantly associated with a higher risk of colorectal cancer [43(3.4%) vs. 25(2.0%); HR 1.77; 95% CI, 1.08-2.90, P = 0.02].

CONCLUSIONS

Folic acid and vitamin B12 supplementation was associated with an increased risk of colorectal cancer.

IMPACT

Our findings suggest that folic acid and vitamin B12 supplementation may increase the risk of colorectal cancer. Further confirmation in larger studies and in meta-analyses combining both folic acid and vitamin B12 are needed to evaluate whether folic acid and vitamin B12 supplementation should be limited to patients with a known indication, such as a proven deficiency.

The intricate connection between diet, microbiota, and cancer: A jigsaw puzzle

The microbial community has a decisive role in determining our health and disease susceptibility. Presumably, this is closely associated with the complex community network of bacteria, fungi, archaea and viruses that reside our guts. This dynamic ecosystem exists in a symbiotic relationship with its host and plays a fundamental role in the hosts' physiological functions. The microbial community is highly personalized and therefore exhibits a high degree of inter-individual variability, which is dependent on host specifics such as genetic background, physiology and lifestyle. Although the gut microbiota is shaped early on during birth, there are several factors that affect the composition of microbiota during childhood and adulthood. Among them diet appears to be a consistent and prominent one. The metabolic activity of bacteria affects food digestion, absorption, energy production, and immunity. Thus, definition of the microbiota composition and functional profiles in response to a particular diet may lead to critical information on the direct and indirect role/use of the bacterial community during health and disease. In this review, I discuss gut microbiota and its potential link to cancer with specific emphasis on metabolism and diet.

Intestinal microbiota is altered in patients with colon cancer and modified by probiotic intervention

Objective

The colonic microbiota is altered in patients with colorectal cancer (CRC). We investigated the microbiota composition of patients with colon cancer compared with controls devoid of neoplastic or inflammatory disease and the potential to modify the colonic microbiota with probiotics.

Design

Biopsy samples were obtained from the normal mucosa and tumour during colonoscopy from 15 patients with colon cancer. Subsequent patient-matched samples were taken at surgery from the tumour and nearby mucosa from the patients with cancer, eight of whom had received two daily tablets totalling 1.4×10¹⁰ CFUs Bifidobacterium lactis Bl-04 and 7×10⁹ CFUs Lactobacillus acidophilus NCFM. Faecal samples were obtained after colonoscopy prior to starting the intervention and at surgery. In addition, 21 mucosal biopsies from non-cancer controls were obtained during colonoscopy followed by later faecal samples. The colonic and faecal microbiota was assessed by 16S rRNA gene amplicon sequencing.

Results

The tumour microbiota was characterised by increased microbial diversity and enrichment of several taxa including Fusobacterium, Selenomonas and Peptostreptococcus compared with the control microbiota. Patients with colon cancer that received probiotics had an increased abundance of butyrate-producing bacteria, especially Faecalibacterium and Clostridiales spp in the tumour, non-tumour mucosa and faecal microbiota. CRC-associated genera such as Fusobacterium and Peptostreptococcus tended to be reduced in the faecal microbiota of patients that received probiotics.

Conclusions

Patients with colon cancer harbour a distinct microbiota signature in the tumour tissue and nearby mucosa, which was altered with probiotic intervention. Our results show promise for potential therapeutic benefits in CRC by manipulation of the microbiota.

Trial registration number

NCT03072641; Results.

A metagenomic study of the preventive effect of Lactobacillus rhamnosus GG on intestinal polyp formation in ApcMin/+ mice

AIMS

To investigate the in vivo effects of Lactobacillus rhamnosus GG (LGG) on intestinal polyp development and the interaction between this single-organism probiotic and the gut microbiota therein.

METHODS AND RESULTS

The Apc^Min/+ mouse model was used to study the potential preventive effect of LGG on intestinal polyposis, while shotgun metagenomic sequencing was employed to characterize both taxonomic and functional changes within the gut microbial community. We found that the progression of intestinal polyps in the control group altered the community functional profile remarkably despite small variation in the taxonomic diversity. In comparison, the consumption of LGG helped maintain the overall functional potential and taxonomic profile in the resident microbes, thereby leading to a 25% decrease of total polyp counts. Furthermore, we found that LGG enriched those microbes or microbial activities related to short-chain fatty acid production (e.g. Roseburia and Coprococcus), as well as suppressed the ones that can lead to inflammation (e.g. Bilophila wadsworthia).

CONCLUSIONS

Our study using shotgun metagenomics highlights how single probiotic LGG may exert its beneficial effects and decrease polyp formation in mice by maintaining gut microbial functionality.

SIGNIFICANCE AND IMPACT OF THE STUDY

This probiotic intervention targeting microbiota may be used in conjugation with other dietary supplements or drugs as part of prevention strategies for early-stage colon cancer, after further clinical validations in human.

Development of an Ex Vivo Organ Culture Technique to Evaluate Probiotic Utilization in IBD

The consistent technical and conceptual progress in the study of the microbiota has led novel impulse to the research for therapeutical application of probiotic bacteria in human pathologies, such as inflammatory bowel disease (IBD). Considering the heterogenous results of probiotics in clinical studies, the model of translational medicine may lead to a more specific and efficacious utilization of probiotic bacteria in IBD. In this regard, the selection and utilization of appropriate experimental models may drive the transition from pure in vitro systems to practical clinical application. We developed a simple and reproducible ex vivo organ culture method with potential utilization for the evaluation of probiotic bacteria efficacy in IBD patients.

The predominant site of bacterial translocation across the intestinal mucosal barrier occurs at the advancing disease margin in Crohn's disease

Crohn's disease is characterized by increased permeability of the intestinal mucosal barriers and an abnormal or dysregulated immune response to specific and/or commensal bacteria arising from the intestinal lumen. To determine the types of bacteria that are transgressing the mucosal barrier and colonizing the intestinal submucosal tissues, we performed 16S rRNA gene microbiota sequencing of the submucosal and mucosal tissues at the advancing disease margin in ileal Crohn's disease. Microbial populations were compared between mucosa and submucosa and non-inflammatory bowel disease (non-IBD) controls, as well as to microbial populations previously found at the centre of the disease lesion. There was no significant increase in bacteria within the submucosa of non-IBD controls at any taxonomic level when compared to the corresponding superjacent mucosa, indicating an effective mucosal barrier within the non-IBD population. In contrast, there was a statistically significant increase in 13 bacterial families and 16 bacterial genera within the submucosa at the advancing disease margin in Crohn's disease when compared to the superjacent mucosa. Major increases within the submucosa included bacteria of the Families Sphingomonadaceae, Alicyclobacillaceae, Methylobacteriaceae, Pseudomonadaceae and Prevotellaceae. Data suggest that the primary site of bacterial translocation across the mucosal barrier occurs at the margin between diseased and normal tissue, the advancing disease margin. The heterogeneity of the bacterial populations penetrating the mucosal barrier and colonizing the submucosal intestinal tissues and, therefore, contributing to the inflammatory processes, suggests that bacterial translocation is secondary to a primary event leading to a breakdown of the mucosal barrier.

Current Understanding of Dysbiosis in Disease in Human and Animal Models

Inflammatory bowel disease (IBD) is an intestinal inflammatory condition that affects more than 2 million people in the United States. Although the etiology and pathogenesis of IBD are still largely unknown, dysregulated host/enteric microbial interactions are requisite for the development of IBD. So far, many researchers have tried to identify a precise relationship between IBD and an imbalance of the intestinal microbiota, termed "dysbiosis." Despite extensive efforts, it is still largely unknown about the interplay among microbes, their hosts, and their environments, and whether dysbiosis is a causal factor or an effect of IBD. Recently, deep-sequencing analyses of the microbiota in patients with IBD patients have been instrumental in characterizing the strong association between dysbiosis and IBD development, although it is still unable to identify specific-associated species level changes in most cases. Based on many recent reports, dysbiosis of the commensal microbiota is implicated in the pathogenesis of several diseases, including IBD, obesity, and allergic disorders, in both human and animal models. In this review article, the authors have focused on explaining the multiple types of dysbiosis, as well as dysbiosis-related diseases and potential treatments to apply this knowledge to understand a possible cause and potentially find therapeutic strategies for IBD as well as the other dysbiosis-related diseases.

Protective effect of agaro-oligosaccharides on gut dysbiosis and colon tumorigenesis in high-fat diet-fed mice

High-fat diet (HFD)-induced alteration in the gut microbial composition, known as dysbiosis, is increasingly recognized as a major risk factor for various diseases, including colon cancer. This report describes a comprehensive investigation of the effect of agaro-oligosaccharides (AGO) on HFD-induced gut dysbiosis, including alterations in short-chain fatty acid contents and bile acid metabolism in mice. C57BL/6N mice were fed a control diet or HFD, with or without AGO. Terminal restriction fragment-length polymorphism (T-RFLP) analysis produced their fecal microbiota profiles. Profiles of cecal organic acids and serum bile acids were determined, respectively, using HPLC and liquid chromatography-tandem mass spectrometry systems. T-RFLP analyses showed that an HFD changed the gut microbiota significantly. Changes in the microbiota composition induced by an HFD were characterized by a decrease in the order Lactobacillales and by an increase in the Clostridium subcluster XIVa. These changes of the microbiota community generated by HFD treatment were suppressed by AGO supplementation. As supported by the data of the proportion of Lactobacillales order, the concentration of lactic acid increased in the HFD + AGO group. Data from the serum bile acid profile showed that the level of deoxycholic acid, a carcinogenic secondary bile acid produced by gut bacteria, was increased in HFD-receiving mice. The upregulation tended to be suppressed by AGO supplementation. Finally, results show that AGO supplementation suppressed the azoxymethane-induced generation of aberrant crypt foci in the colon derived from HFD-treated mice. Our results suggest that oral intake of AGO prevents HFD-induced gut dysbiosis, thereby inhibiting colon carcinogenesis.

Lactobacillus casei Exerts Anti-Proliferative Effects Accompanied by Apoptotic Cell Death and Up-Regulation of TRAIL in Colon Carcinoma Cells

Probiotic microorganisms such as lactic acid bacteria (LAB) exert a number of strain-specific health-promoting activities attributed to their immunomodulatory, anti-inflammatory and anti-carcinogenic properties. Despite recent attention, our understanding of the biological processes involved in the beneficial effects of LAB strains is still limited. To this end, the present study investigated the growth-inhibitory effects of Lactobacillus casei ATCC 393 against experimental colon cancer. Administration of live Lactobacillus casei (as well as bacterial components thereof) on murine (CT26) and human (HT29) colon carcinoma cell lines raised a significant concentration- and time-dependent anti-proliferative effect, determined by cell viability assays. Specifically, a dramatic decrease in viability of colon cancer cells co-incubated with 10(9) CFU/mL L. casei for 24 hours was detected (78% for HT29 and 52% for CT26 cells). In addition, live L. casei induced apoptotic cell death in both cell lines as revealed by annexin V and propidium iodide staining. The significance of the in vitro anti-proliferative effects was further confirmed in an experimental tumor model. Oral daily administration of 10(9) CFU live L. casei for 13 days significantly inhibited in vivo growth of colon carcinoma cells, resulting in approximately 80% reduction in tumor volume of treated mice. Tumor growth inhibition was accompanied by L. casei-driven up-regulation of the TNF-related apoptosis-inducing ligand TRAIL and down-regulation of Survivin. Taken together, these findings provide evidence for beneficial tumor-inhibitory, anti-proliferative and pro-apoptotic effects driven by this probiotic LAB strain.

The gut microbiota and host health: a new clinical frontier

Over the last 10-15 years, our understanding of the composition and functions of the human gut microbiota has increased exponentially. To a large extent, this has been due to new 'omic' technologies that have facilitated large-scale analysis of the genetic and metabolic profile of this microbial community, revealing it to be comparable in influence to a new organ in the body and offering the possibility of a new route for therapeutic intervention. Moreover, it might be more accurate to think of it like an immune system: a collection of cells that work in unison with the host and that can promote health but sometimes initiate disease. This review gives an update on the current knowledge in the area of gut disorders, in particular metabolic syndrome and obesity-related disease, liver disease, IBD and colorectal cancer. The potential of manipulating the gut microbiota in these disorders is assessed, with an examination of the latest and most relevant evidence relating to antibiotics, probiotics, prebiotics, polyphenols and faecal microbiota transplantation.

Role of intestinal flora and defensins in colorectal carcinogenesis

Colorectal cancer is a common malignant tumor of the digestive system. In recent years, the morbidity and mortality of colorectal cancer in China have been rising continuously, causing heavy medical burden; however, the exact etiology is still unknown. Therefore, there is an urgent need to elucidate the etiology and pathogenesis of colorectal cancer to promote early prevention, effective screening and targeted therapy. At present, the research on the correlation between intestinal flora and colorectal cancer is being deepened constantly. Defensins, mediating interaction between intestinal flora and the intestinal mucosa, have attracted more and more attention because of their potential role in the development of colorectal cancer. Here we briefly introduce human intestinal flora and defensins, review new advances in our understanding of their role in colorectal carcinogenesis and the possible mechanism, and preliminarily explore their mutual interaction.

Unmethylated CpG motifs inToxoplasma gondiiDNA induce TLR9- and IFN-β-dependent expression ofα-defensin-5 in intestinal epithelial cells

The gut epithelial barrier is a strategic place to prevent, or at least to limit, parasite dissemination upon oral infection withToxoplasma gondii. Innate immunity to this pathogen results from delicate interactions involving different components of the infecting agent and the host. We herein aimed to examine the molecular mechanism by which protozoan DNA boosts the production ofα-defensin-5 (DEFA-5), the main antimicrobial peptide at the target site of infection. The present study shows that DEFA-5 is rapidly upregulated in intestinal epithelial cells following intracellular Toll-like receptor 9 (TLR9) activation by unmethylated CpG motifs in DNA fromT. gondii(CpG-DNA). Concomitantly, CpG-DNA purified from the pathogen markedly increased TLR9 mRNA expression levels in the Caco-2 cell line. We further verified that DEFA-5 production was dependent on interferon-βreleased from these cells upon treatment with CpG-DNA prepared from tachyzoites. Our results suggest that, in protozoan DNA-stimulated intestinal epithelial cells, the TLR9/interferon-β/DEFA-5 pathway may initiate an innate anti-T. gondiiresponse without the need of parasite invasion. These findings highlight the key role of the gut epithelium in Toxoplasma recognition and amplification of local host defence against this microbe, thereby contributing to gain insight into immunoprotective mechanisms and to improve therapeutic strategies.

Effect of bifidobacterium on defensin-5 expression in intestinal injury of preweaning rats

AIM: To investigate the protective effect of bifidobacterium in endotoxin-induced intestinal injury in preweaning rats.

METHODS: Preweaning rats were randomly divided into three groups (n = 40 for each): a control group (group C), a model group (group E) and a treatment group (group T). Both groups E and T were intraperitoneally injected with lipopolysaccharide (LPS) at a dose of 5 mg/kg (5 mg/L in normal saline), and group T was intragastrically administrated with bifidobacterium suspension (2.0 × 10⁹ CFU/mL, 0.5 mL each time, twice a day, until the end of the experiment) 7 d before LPS administration. Group C was intraperitoneally injected with normal saline. After intraperitoneal injection and intragastric administration, the rats were placed back to the initial cage to receive breast feeding. The rats were killed at 2, 6, 12, 24 or 72 h, respectively, after endotoxin or physiological saline injection to collect serum and ileal tissue samples. Myeloperoxidase (MPO) contents in serum and ileum were detected at different times, and expression of ileal defensin-5 mRNA was evaluated by reverse transcription-polymerase chain reaction.

RESULTS: Serum and ileal MPO contents in group E were significantly higher than those in group C (serum contents: 107.50 ± 17.70 vs 157.14 ± 24.67, P < 0.05; ileal contents: 1.03 ± 0.21 vs 1.57 ± 0.33, P < 0.05), which peaked at 12 h and 6 h, respectively. MPO contents in group T were significantly lower than those in group E (serum contents: 114.38 ± 24.56 vs 145.25 ± 23.62, P < 0.05; ileal contents: 1.25 ± 0.24 vs 1.57 ± 0.33, P < 0.05). The expression of defensin-5 mRNA in group E was significantly higher than that in group C (0.953 ± 0.238 vs 0.631 ± 0.146, P < 0.05), which peaked at 2 h, and then decreased gradually. The expression of defensin-5 mRNA in group T was significantly lower than that in group E (0.487 ± 0.149 vs 0.758 ± 0.160, P < 0.05) apparently in 24 h. The expression of defensin-5 mRNA at 2 h in group T was significantly higher than that in group C (0.824 ± 0.158 vs 0.631 ± 0.146, P < 0.05).

CONCLUSION: MPO and defensin-5 mRNA increase in preweaning rats with LPS-induced intestinal injury. Bifidobacterium protects the gut by inhibiting MPO activity, not by increasing defensin-5 secretion.

The gastrointestinal microbiota and colorectal cancer

The human gut is home to a complex and diverse microbiota that contributes to the overall homeostasis of the host. Increasingly, the intestinal microbiota is recognized as an important player in human illness such as colorectal cancer (CRC), inflammatory bowel diseases, and obesity. CRC in itself is one of the major causes of cancer mortality in the Western world. The mechanisms by which bacteria contribute to CRC are complex and not fully understood, but increasing evidence suggests a link between the intestinal microbiota and CRC as well as diet and inflammation, which are believed to play a role in carcinogenesis. It is thought that the gut microbiota interact with dietary factors to promote chronic inflammation and CRC through direct influence on host cell physiology, cellular homeostasis, energy regulation, and/or metabolism of xenobiotics. This review provides an overview on the role of commensal gut microbiota in the development of human CRC and explores its association with diet and inflammation.

Cancer and the microbiome: potential applications as new tumor biomarker

Microbial communities that colonize in humans are collectively described as microbiome. According to conservative estimates, about 15% of all types of neoplasms are related to different infective agents. However, current knowledge is not sufficient to explain how the microbiome contributes to the growth and development of cancers. Large and thorough studies involving colonized, diverse and complex microbiome entities are required to identify microbiome as a potential cancer marker and to understand how the immune system is involved in response to pathogens. This article reviews the existing evidence supporting the enigmatic association of transformed microbiome with the development of cancer through the immunological modification. Ascertaining the connection between microbiome and immunological responses with risk of cancer may direct to explaining significant advances in the etiology of cancer, potentially disclosing a novel paradigm of research for the management and prevention of cancer.

Detection of colorectal cancer (CRC) by urinary volatile organic compound analysis

Colorectal cancer (CRC) is a leading cause of cancer related death in Europe and the USA. There is no universally accepted effective non-invasive screening test for CRC. Guaiac based faecal occult blood (gFOB) testing has largely been superseded by Faecal Immunochemical testing (FIT), but sensitivity still remains poor. The uptake of population based FOBt testing in the UK is also low at around 50%. The detection of volatile organic compounds (VOCs) signature(s) for many cancer subtypes is receiving increasing interest using a variety of gas phase analytical instruments. One such example is FAIMS (Field Asymmetric Ion Mobility Spectrometer). FAIMS is able to identify Inflammatory Bowel disease (IBD) patients by analysing shifts in VOCs patterns in both urine and faeces. This study extends this concept to determine whether CRC patients can be identified through non-invasive analysis of urine, using FAIMS. 133 patients were recruited; 83 CRC patients and 50 healthy controls. Urine was collected at the time of CRC diagnosis and headspace analysis undertaken using a FAIMS instrument (Owlstone, Lonestar, UK). Data was processed using Fisher Discriminant Analysis (FDA) after feature extraction from the raw data. FAIMS analyses demonstrated that the VOC profiles of CRC patients were tightly clustered and could be distinguished from healthy controls. Sensitivity and specificity for CRC detection with FAIMS were 88% and 60% respectively. This study suggests that VOC signatures emanating from urine can be detected in patients with CRC using ion mobility spectroscopy technology (FAIMS) with potential as a novel screening tool.

Novel Testing Enhances Irritable Bowel Syndrome Medical Management: The IMMINENT Study

Primary Study Objective:

To evaluate the economic utility of a fecal biomarker panel structured to suggest alternative, treatable diagnoses in patients with symptoms of irritable bowel syndrome (IBS) by quantifying, comparing, and contrasting health service costs between tested and non-tested patients.

Study Design:

Retrospective, matched cohort study comparing direct medical costs for IBS patients undergoing fecal biomarker testing with those of matched control subjects.

Methods:

We examined de-identified medical and pharmacy claims of a large American pharmacy benefit manager to identify plan members who underwent panel testing, were eligible for covered benefits for at least 180 days prior to the test date, and had data available for 30, 90, and 365 days after that date. We used propensity score matching to develop population-based control cohorts for each tested cohort, comprised of records with IBS-related diagnoses but for which panel testing was not performed. Primary outcome measures were diagnostic and medical services costs as determined from claims data.

Results:

Two hundred nine records from tested subjects met inclusion criteria. The only significant baseline differences between groups were laboratory costs, which were significantly higher in each tested cohort. At each follow-up time point, total medical and gastrointestinal procedural costs were significantly higher in non-tested cohorts. Within tested cohorts, costs declined significantly from baseline, while costs rose significantly in non-tested control cohorts; these differences were also significant between groups at each time point.

Conclusions:

Structured fecal biomarker panel testing was associated with significantly lower medical and gastrointestinal procedural costs in this study of patients with IBS symptoms.

Gastrointestinal cancers: influence of gut microbiota, probiotics and prebiotics

Cancers of the gastrointestinal (GI) tract continue to represent a major health problem, despite progress in therapy. Gut microbiota is a key element related to the genesis of GI cancers, countless papers addressing this burning issue across the world. We provide an updated knowledge of the involvement of gut microbiota in GI tumorigenesis, including its underlying mechanisms. We present also a comprehensive review of the evidence from animal and clinical studies using probiotics and/or prebiotics in the prevention and/or therapy of GI tumours, of GI cancer therapy-related toxicity and of post-operative complications. We summarize the anticarcinogenic mechanisms of these biotherapeutics from in vitro, animal and clinical interventions. More research is required to reveal the interactions of microflora with genetic, epigenetic and immunologic factors, diet and age, before any firm conclusion be drawn. Well-designed, randomized, double blind, placebo-controlled human studies using probiotics and/or prebiotics, with adequate follow-up are necessary in order to formulate directions for prevention and therapy.

Infection, antibiotic therapy and risk of colorectal cancer: a nationwide nested case-control study in patients with Type 2 diabetes mellitus

Patients with Type 2 diabetes mellitus are at a higher risk of colorectal cancer (CRC). The objective of our study was to examine the inter-relationship among infection sites, systemic antibiotic use and risk of CRC among patients with Type 2 diabetes mellitus. From a diabetic cohort from the Taiwan's National Health Insurance claims database, we identified 3,593 incident colon cancer cases, 1,979 rectal cancer cases and 22,288 controls and conducted a nested case-control study to examine the association between antibiotic use and CRC incidence. Logistic regression models were applied to estimate the odds ratio (OR) and the 95% confidence interval (95% CI) between infection sites, antibiotic use and CRC incidence. Patients with intra-abdominal infection were significantly associated with increased risk for colon cancer (OR = 2.01, 95% CI = 1.73-2.35) and rectal cancer (OR = 1.59, 95% CI = 1.26-2.00). Any antianaerobic antibiotic use was associated with a higher risk of colon cancer (OR = 2.31, 95% CI = 2.12-2.52) and rectal cancer (OR = 1.69, 95% CI = 1.50-1.90) but without an obvious dose-response relationship for cumulative use. Antianaerobic antibiotics also increased the risks for those with nonintra-abdominal infection. No association was found between antiaerobic agent use and the CRC risk. The results suggest intra-abdominal infections and antianaerobic antibiotic use may be a marker for precancerous lesions or early CRC, although the possibility of antianaerobic antibiotics playing an additional role cannot be excluded. Further research examining the relationship between intra-abdominal infection, antianaerobic antibiotics use and possible change of microbiota leading to colorectal carcinogenesis is warranted.

Development and validation of a highly sensitive urine-based test to identify patients with colonic adenomatous polyps

Objectives:

Adenomatous polyps are precursors of colorectal cancer; their detection and removal is the goal of colon cancer screening programs. However, fecal-based methods identify patients with adenomatous polyps with low levels of sensitivity. The aim or this study was to develop a highly accurate, prototypic, proof-of-concept, spot urine-based diagnostic test using metabolomic technology to distinguish persons with adenomatous polyps from those without polyps.

Methods:

Prospective urine and stool samples were collected from 876 participants undergoing colonoscopy examination in a colon cancer screening program, from April 2008 to October 2009 at the University of Alberta. Colonoscopy reference standard identified 633 participants with no colonic polyps and 243 with colonic adenomatous polyps. One-dimensional nuclear magnetic resonance spectra of urine metabolites were analyzed to define a diagnostic metabolomic profile for colonic adenomas. A urine metabolomic diagnostic test for colonic adenomatous polyps was established using 67% of the samples (un-blinded training set) and validated using the other 33% of the samples (blinded testing set). The urine metabolomic diagnostic test's specificity and sensitivity were compared with those of fecal-based tests.

Results:

Using a two-component, orthogonal, partial least-squares model of the metabolomic profile, the un-blinded training set identified patients with colonic adenomatous polyps with 88.9% sensitivity and 50.2% specificity. Validation using the blinded testing set confirmed sensitivity and specificity values of 82.7% and 51.2%, respectively. Sensitivities of fecal-based tests to identify colonic adenomas ranged from 2.5 to 11.9%.

Conclusions:

We describe a proof-of-concept spot urine-based metabolomic diagnostic test that identifies patients with colonic adenomatous polyps with a greater level of sensitivity (83%) than fecal-based tests.

Downregulation of hematopoietic MUC1 during experimental colitis increases tumor-promoting myeloid-derived suppressor cells

PURPOSE

MUC1 is a tumor-associated antigen that is aberrantly expressed in cancer and inflammatory bowel disease (IBD). Even though immune cells express low MUC1 levels, their modulations of MUC1 are important in tumor progression. Consistent with previous clinical data that show increased myeloid-derived suppressor cells (MDSCs) in IBD, we now show that downregulation of MUC1 on hematopoietic cells increases MDSCs in IBD, similar to our data in tumor-bearing mice. We hypothesize that MDSC expansion in IBD is critical for tumor progression.

EXPERIMENTAL DESIGN

To mechanistically confirm the linkage between Muc1 downregulation and MDSC expansion, we generated chimeric mice that did not express Muc1 in the hematopoietic compartment (KO→WT). These mice were used in two models of colitis and colitis-associated cancer (CAC) and their responses were compared with wild-type (WT) chimeras (WT→WT).

RESULTS

KO→WT mice show increased levels of MDSCs during colitis and increased protumorigenic signaling in the colon during CAC, resulting in larger colon tumors. RNA and protein analysis show increased upregulation of metalloproteinases, collagenases, defensins, complements, growth factors, cytokines, and chemokines in KO→WT mice as compared with WT→WT mice. Antibody-mediated depletion of MDSCs in mice during colitis reduced colon tumor formation during CAC.

CONCLUSION

Development of CAC is a serious complication of colitis and our data highlight MDSCs as a targetable link between inflammation and cancer. In addition, the lack of MUC1 expression on MDSCs can be a novel marker for MDSCs, given that MDSCs are still not well characterized in human cancers.

Microbial dysbiosis and colon carcinogenesis: could colon cancer be considered a bacteria-related disease?

Colorectal cancer (CRC) is posing an increasingly important burden on the health care system, with western countries seeing a growing incidence of the disease. Except for germline DNA mutations which have been attributed to less than 5% of patients, little is known about the main causes of CRC. However, environment factors such as food, lifestyle and medication are now suspected to have a major influence on inducing cancers. Today, exhaustive quantitative and qualitative evaluation of all environmental factors is not possible. Various environment-induced diseases have been characterized based on colon microflora, also called microbiota, analyses. Growing data have shown specific changes in microflora (i.e. dysbiosis) in the stools of patients with colon cancer or those adherent to the colonic mucosa. Thus, it appears that microbiota may be considered a platform offering host and environment interactions for studying CRCs. The hypothesis that colon cancer might be a bacteria-related disease is suggested and perspectives are discussed.

Microbial dysbiosis and colon carcinogenesis: could colon cancer be considered a bacteria-related disease?

Colorectal cancer (CRC) is posing an increasingly important burden on the health care system, with western countries seeing a growing incidence of the disease. Except for germline DNA mutations which have been attributed to less than 5% of patients, little is known about the main causes of CRC. However, environment factors such as food, lifestyle and medication are now suspected to have a major influence on inducing cancers. Today, exhaustive quantitative and qualitative evaluation of all environmental factors is not possible. Various environment-induced diseases have been characterized based on colon microflora, also called microbiota, analyses. Growing data have shown specific changes in microflora (i.e. dysbiosis) in the stools of patients with colon cancer or those adherent to the colonic mucosa. Thus, it appears that microbiota may be considered a platform offering host and environment interactions for studying CRCs. The hypothesis that colon cancer might be a bacteria-related disease is suggested and perspectives are discussed.

Systemic folate status, rectal mucosal folate concentration and dietary intake in patients at differential risk of bowel cancer (The FAB2 Study)

BACKGROUND/OBJECTIVES

Folate has been strongly implicated in the aetiology of colorectal cancer. However, the relationship between dietary folate intake, rectal mucosal folate status and colorectal cancer risk is uncertain. The study aimed to estimate nutrient intakes and measure systemic folate status and rectal mucosal folate concentration in people at differential risk of developing colorectal cancer.

METHODS

Two hundred and twenty-eight individuals were recruited from gastroenterology clinics and subdivided into three patient groups: untreated colorectal cancer (n = 43), adenomatous polyps (n = 90) or normal bowel (n = 95). Biopsies from macroscopically normal rectal mucosa and blood were collected and used for the measurement of rectal mucosal 5-methyltetrahydrofolate (5-MeTHF) and systemic markers of folate status, respectively. Nutrient intake was estimated using a validated food frequency questionnaire.

RESULTS

Dietary intake variables, plasma 5-MeTHF and red cell folate and plasma homocysteine concentrations were similar in all three subject groups and 95% CI fell within normal range for each variable. Rectal mucosal 5-MeTHF concentration was higher in the normal mucosa of adenomatous polyp patients than in normal subjects (P = 0.055). Rectal mucosal 5-MeTHF was associated significantly with plasma folate (P < 0.001, r = 0.294), red cell folate (P = 0.014, r = 0.305), plasma homocysteine (P = 0.017, r = -0.163) and dietary folate intake (P = 0.036, r = 0.152).

CONCLUSIONS

This study demonstrates adequate folate status of patients attending gastroenterology clinics for the investigation of bowel symptoms, with no significant difference in dietary intakes or systemic folate status indices according to diagnosis. Rectal mucosal 5-MeTHF concentrations were elevated in adenomatous polyp patients, but failed to reach significance. Further studies are required to determine the biological significance of this observation.

Normal to cancer microbiome transformation and its implication in cancer diagnosis

Microbial communities coexisting with humans are collectively known as microbiome. It influences almost every aspect of an individual's body function. Microbiome is idiosyncratic for body condition and its alteration is indicative for several abnormalities. This article discusses about recent ideas for developing microbiology based cancer indicators using alterations in microbiome. It is noteworthy that large exploratory studies are required to identify cancer indicator microorganisms from complex and diverse microbiome constituents. This complexity also warrants that these markers should be used in conjunction with other routine cancer indicators. The present article concludes that such studies can spur development of novel microbiome based cancer diagnostics.

Crohn's disease and the mycobacterioses: a quarter century later. Causation or simple association?

It has been more than 25 years since Mycobacterium paratuberculosis was first proposed as an etiologic agent in Crohn's disease based on the isolation of this organism from several patients. Since that time, a great deal of information has been accumulated that clearly establishes an association between M. paratuberculosis and Crohn's disease. However, data are conflicting and difficult to interpret and the field has become divided into committed advocates and confirmed skeptics. This review is an attempt to provide a thorough and objective summary of current knowledge from both basic and clinical research from the views and interpretations of both the antagonists and proponents. The reader is left to draw his or her own conclusions related to the validity of the issues and claims made by the opposing views and data interpretations. Whether M. paratuberculosis is a causative agent in some cases or simply represents an incidental association remains a controversial topic, but current evidence suggests that the notion should not be so readily dismissed. Remaining questions that need to be addressed in defining the role of M. paratuberculosis in Crohn's disease and future implications are discussed.

Mucin depleted foci, colonic preneoplastic lesions lacking Muc2, show up-regulation of Tlr2 but not bacterial infiltration

Mucin depleted foci (MDF) are precancerous lesions of the colon in carcinogen-treated rodents and humans at high risk. Since MDF show signs of inflammation we hypothesized that the defective mucous production would expose them to the risk of being penetrated by intestinal bacteria, which can be sensed by Toll-like receptors (Tlrs) and activate inflammatory pathways. To verify this hypothesis we tested the expression of 84 genes coding for Tlrs and associated pathways using RT-qPCR in MDF (n = 7) from 1,2-dimethylhydrazine (DMH)-treated rats. Among the 84 tested genes, 26 were differentially expressed in MDF with 5 genes significantly up-regulated and 21 down-regulated when compared to the normal mucosa. Tlr2, as well as other downstream genes (Map4k4, Hspd1, Irak1, Ube2n), was significantly up-regulated. Among the genes regulating the NFkB pathway, only Map4k4 was significantly up-regulated, while 19 genes were not varied and 6 were down-regulated. Tlr2 protein was weakly expressed both in normal mucosa and MDF. To determine whether inflammation observed in MDF could be caused by bacteria contacting or infiltrating crypts, we performed fluorescence in situ hybridization (FISH) experiments with a rRNA universal bacterial probe. None of the 21 MDF tested, showed bacteria inside the crypts, while among the colonic tumors (n = 15), only one had very few bacteria on the surface and on the surrounding normal mucosa. In conclusion, the up-regulation of Tlr2 in MDF, suggests a link between this receptor and carcinogenesis, possibly related to a defective barrier function of these lesions. The data of FISH experiments do not support the hypothesis that inflammation in MDF and tumors is stimulated by bacterial infiltration.