Multi-omics approach to socioeconomic disparity in metabolic syndrome reveals roles of diet and microbiome.

The epidemy of metabolic syndrome (MetS) is typically preceded by adoption of a "risky" lifestyle (e.g., dietary habit) among populations. Evidence shows that those with low socioeconomic status (SES) are at an increased risk for MetS. To investigate this, we recruited 123 obese subjects (body mass index [BMI] ≥ 30) from Chicago. Multi-omic data were collected to interrogate fecal microbiota, systemic markers of inflammation and immune activation, plasma metabolites, and plasma glycans. Intestinal permeability was measured using the sugar permeability testing. Our results suggest a heterogenous metabolic dysregulation among obese populations who are at risk of MetS. Systemic inflammation, linked to poor diet, intestinal microbiome dysbiosis, and gut barrier dysfunction may explain the development of MetS in these individuals. Our analysis revealed 37 key features associated with increased numbers of MetS features. These features were used to construct a composite metabolic-inflammatory (MI) score that was able to predict progression of MetS among at-risk individuals. The MI score was correlated with several markers of poor diet quality as well as lower levels of gut microbial diversity and abnormalities in several species of bacteria. This study reveals novel targets to reduce the burden of MetS and suggests access to healthy food options as a practical intervention.

Novel role of the Mu-opioid receptor in pancreatic cancer: potential link between opioid use and cancer progression.

Opioids are the most popular drugs for both acute and chronic pain management. The G protein-coupled mu-opioid receptor (MOR) is the therapeutic target for most clinically used opioids, including morphine. A mounting number of publications suggest a relationship between the MOR and possible cancer progression and recurrence extending to managing chronic cancer pain. In this study, we studied the possible link between opioid use and pancreatic cancer (PC) progression. We found increased MOR expression in murine and human PC cell lines, human PC-derived organoids, and in the undifferentiated or poorly differentiated areas of surgically resected PC tissues. Direct stimulation of MOR by morphine (MOR agonist) caused a significant dose-dependent increase in proliferation, invasion, and levels of stemness markers in PC cells. In a co-culture system, MOR stimulation of macrophages also resulted in increased proliferation of PC cells. MOR overexpression increased proliferation and cancer stemness, whereas knock-down of MOR followed opposite results in the PC cells. Morphine induced chemoresistance to conventional chemotherapeutic agents used for PC treatment. Overall, our results suggest that MOR is expressed in pancreatic cancer and may be involved in tumor progression and chemoresistance.

Alcohol use disorder as a potential risk factor for COVID-19 severity: A narrative review.

In Dec. 2019-January 2020, a pneumonia illness originating in Wuhan, China, designated as coronavirus disease 2019 (COVID-19) was shown to be caused by a novel RNA coronavirus designated as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). People with advanced age, male sex, and/or underlying health conditions (obesity, type 2 diabetes, cardiovascular disease, hypertension, chronic kidney disease, and chronic lung disease) are especially vulnerable to severe COVID-19 symptoms and death. These risk factors impact the immune system and are also associated with poor health, chronic illness, and shortened longevity. However, a large percent of patients without these known risk factors also develops severe COVID-19 disease that can result in death. Thus, there must exist risk factors that promote exaggerated inflammatory and immune response to the SARS-CoV-2 virus leading to death. One such risk factor may be alcohol misuse and alcohol use disorder because these can exacerbate viral lung infections like SARS, influenza, and pneumonia. Thus, it is highly plausible that alcohol misuse is a risk factor for either increased infection rate when individuals are exposed to SARS-CoV-2 virus and/or more severe COVID-19 in infected patients. Alcohol use is a well-known risk factor for lung diseases and ARDS in SARS patients. We propose that alcohol has three key pathogenic elements in common with other COVID-19 severity risk factors: namely, inflammatory microbiota dysbiosis, leaky gut, and systemic activation of the NLRP3 inflammasome. We also propose that these three elements represent targets for therapy for severe COVID-19.

Gastrointestinal Symptoms Predict the Outcomes From COVID-19 Infection.

Coronavirus disease 2019 (COVID-19) has taken hundreds of thousands of lives globally. Besides the respiratory tract, the virus can affect the gastrointestinal (GI) tract. Data regarding the significance of GI symptoms in the COVID-19 course are limited. In this largest US study to date, the authors reviewed electronic encounters of 1003 consecutive patients who were tested positive for the virus between March 12 and April 3, 2020. Initial GI symptoms were present in up to 22.4% of patients and were associated with worse outcomes after adjustment for demographics, comorbidities, and other clinical symptoms. COVID-19 with GI involvement may define a more severe phenotype.

Behavioral circadian phenotypes are associated with the risk of elevated body mass index.

BACKGROUND: Metabolic dysfunction and obesity rates are on the rise. Although the central modes of circadian disruption has been studied in relation to the risk of obesity, the role of eating time has remained unclear. Here, we aimed to assess circadian behavioral phenotypes and their association with the risk of elevated body mass index (BMI). METHODS: This was a prospective cross-sectional study of individuals presenting for colorectal cancer screening colonoscopy. Participants completed demographic questionnaires, The Munich ChronoType Questionnaire (MCTQ), and Food Timing Screener (FTS). The primary outcome of the study was the association between circadian phenotypes and elevated BMI. RESULTS: A total of 488 individuals completed the survey, with a mean (SD) age of 57.5 (10.8) years. The mean body mass index (BMI) was 28.8 (6.1) kg/m2, with 72.3% of individuals met criteria for elevated BMI. Four circadian behavioral phenotypes were generated: early chronotype with regular food timing (ER) (34.7%), early chronotype with irregular food timing (EI) (11.7%), intermediate/late chronotype with regular food timing (LR) (33.9%), and intermediate/late chronotype with irregular food timing (LI) (19.7%). In a multivariable regression analysis, LI phenotype had 2.9 times higher odds of elevated BMI as compared to ER phenotype (OR 2.9, 95% CI 1.3-6.7, P = 0.01). CONCLUSION: The combination of late chronotype and irregular food timing, representative of a behavioral circadian rhythm disruption, is associated with higher rates of elevated BMI. The majority of individuals with this abnormal circadian phenotype were younger than 60 years old. This observation is especially relevant because of the ongoing rise in the obesity rates among young adults. LEVEL III: Evidence obtained from well-designed cohort or case-control analytic studies.

Gut microbiota profile in patients with nonalcoholic fatty liver disease and presumed nonalcoholic steatohepatitis.

Background: The main composition of intestinal microbiota in nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) patients has not yet been elucidated. In this, case-control study, we identified differences of intestinal microbiota in male patients with NAFLD, presumed NASH, and healthy controls. Materials and Methods: We compared gut microbial composition of 25 patients with NAFLD, 13 patients with presumed NASH, and 12 healthy controls. Demographic information as well as clinical, nutritional, and physical activity data was gathered. Stool and blood samples were collected to perform the laboratory analysis. The taxonomic composition of gut microbiota was assessed using V4 regions of microbial small subunit ribosomal Ribonucleic acid genes sequencing of stool samples. Results: Firmicutes, Actinobacteria, and Bacteroidetes were the most frequently phyla in all groups. Our results revealed that Veillonella was the only genus with significantly different amounts in presumed NASH patients compared with patients with NAFLD (P = 2.76 × 10-6, q = 2.07 × 10-4, logFC = 5.52). Conclusion: This pilot study was the first study to compare gut microbial composition in patients with NAFLD and presumed NASH in the Middle East. Given the potential effects of gut microbiota on the management and prevention of NAFLD, larger, prospective studies are recommended to confirm this study's findings.

Interobserver reliability of methods to determine complete resection of adenomas in colonoscopy.

BACKGROUND: Forceps margin biopsy and polypectomy specimen margins have both been used to assess for polypectomy resection adequacy. The interobserver reliability of the two methods has not been well described. METHODS: The interpretability of polypectomy specimens for presence of residual neoplasia at the margin was assessed by two blinded pathologists. Next, the concordance of forceps margin biopsy interpretations between three blinded pathologists was evaluated by calculation of interobserver κ. RESULTS: Rates of polypectomy specimen margin interpretability were low: 24/92 (26 %) for pathologist A, 28/92 (30.4 %) for pathologist B. Concordance of forceps margin biopsy interpretations (n = 129) between pathologists was high. Two internal pathologists showed substantial agreement in margin biopsy interpretations (κ 0.779; 95 %CL 0.543, 0.912). The concordance remained strong after biopsies were reviewed by a third, external pathologist (κ 0.829; 95 %CL 0.658, 0.924). There was complete agreement on 123/129 (95.3 %) between all three pathologists for presence of neoplasia. CONCLUSION: The majority of polypectomy specimen margins were uninterpretable by pathologists for presence of residual neoplasia. Forceps margin biopsy shows strong interobserver reliability in adenomatous lesions.

Assessment of the impact of different fecal storage protocols on the microbiota diversity and composition: a pilot study.

BACKGROUND: Fecal samples are currently the most commonly studied proxy for gut microbiota. The gold standard of sample handling and storage for microbiota analysis is maintaining the cold chain during sample transfer and immediate storage at - 80 °C. Gut microbiota studies in large-scale, population-based cohorts require a feasible sample collection protocol. We compared the effect of three different storage methods and mock shipment: immediate freezing at - 80 °C, in 95% ethanol stored at room temperature (RT) for 48 h, and on blood collection card stored at RT for 48 h, on the measured composition of fecal microbiota of eight healthy, female volunteers by sequencing the V4 region of the 16S rRNA gene on an Illumina MiSeq. RESULTS: Shared operational taxonomic units (OTUs) between different methods were 68 and 3% for OTUs > 0.01 and < 0.01% mean relative abundance within each group, respectively. α and ß-diversity measures were not significantly impacted by different storage methods. With the exception of Actinobacteria, fecal microbiota profiles at the phylum level were not significantly affected by the storage method. Actinobacteria was significantly higher in samples collected on card compared to immediate freezing (1.6 ± 1.1% vs. 0.4 ± 0.2%, p = 0.005) mainly driven by expansion of Actinobacteria relative abundance in fecal samples stored on card in two individuals. There was no statistically significant difference at lower taxonomic levels tested. CONCLUSION: Consistent results of the microbiota composition and structure for different storage methods were observed. Fecal collection on card could be a suitable alternative to immediate freezing for fecal microbiota analysis using 16S rRNA gene amplicon sequencing.

Alcohol Effects on Colon Epithelium are Time-Dependent.

BACKGROUND: Alcohol intake increases the risk of developing colon cancer. Circadian disruption promotes alcohol's effect on colon carcinogenesis through unknown mechanisms. Alcohol's metabolites induce DNA damage, an early step in carcinogenesis. We assessed the effect of time of alcohol consumption on markers of tissue damage in the colonic epithelium. METHODS: Mice were treated by alcohol or phosphate-buffered saline (PBS), at 4-hour intervals for 3 days, and their colons were analyzed for (i) proliferation (Ki67) and antiapoptosis (Bcl-2) markers, (ii) DNA damage (γ-H2AX), and (iii) the major acetaldehyde (AcH)-DNA adduct, N2 -ethylidene-dG. To model circadian disruption, mice were shifted once weekly for 12 h and then were sacrificed at 4-hour intervals. Samples of mice with a dysfunctional molecular clock were analyzed. The dynamics of DNA damage repair from AcH treatment as well as role of xeroderma pigmentosum, complementation group A (XPA) in their repair were studied in vitro. RESULTS: Proliferation and survival of colonic epithelium have daily rhythmicity. Alcohol induced colonic epithelium proliferation in a time-dependent manner, with a stronger effect during the light/rest period. Alcohol-associated DNA damage also occurred more when alcohol was given at light. Levels of DNA adduct did not vary by time, suggesting rather lower repair efficiency during the light versus dark. XPA gene expression, a key excision repair gene, was time-dependent, peaking at the beginning of the dark. XPA knockout colon epithelial cells were inefficient in repair of the DNA damage induced by alcohol's metabolite. CONCLUSIONS: Time of day of alcohol intake may be an important determinant of colon tissue damage and carcinogenicity.

KRAS mutation and epithelial-macrophage interplay in pancreatic neoplastic transformation.

Pancreatic ductal adenocarcinoma (PDA) is characterized by epithelial mutations in KRAS and prominent tumor-associated inflammation, including macrophage infiltration. But knowledge of early interactions between neoplastic epithelium and macrophages in PDA carcinogenesis is limited. Using a pancreatic organoid model, we found that the expression of mutant KRAS in organoids increased (i) ductal to acinar gene expression ratios, (ii) epithelial cells proliferation and (iii) colony formation capacity in vitro, and endowed pancreatic cells with the ability to generate neoplastic tumors in vivo. KRAS mutations induced a protumorigenic phenotype in macrophages. Altered macrophages decreased epithelial pigment epithelial derived factor (PEDF) expression and induced a cancerous phenotype. We validated our findings using annotated patient samples from The Cancer Genome Atlas (TCGA) and in our human PDA specimens. Epithelium-macrophage cross-talk occurs early in pancreatic carcinogenesis where KRAS directly induces cancer-related phenotypes in epithelium, and also promotes a protumorigenic phenotype in macrophages, in turn augmenting neoplastic growth.

Alternative approaches to polyp extraction in colonoscopy: a proof of principle study.

BACKGROUND AND AIMS: A limitation of determination of the completeness of resection in polypectomy is polyp fragmentation. When a polyp fragments, the pathologist cannot determine resection completeness. Alternative approaches to reduce polyp fragmentation include reducing shearing forces on the polyp or removing polyps through the instrument channel. The primary aim of this study was to assess fragmentation of polyps extracted using different approaches from conventional polyp retrieval. METHODS: Polyps (5-15 mm) resected by cold snare or cautery by 3 colonoscopists were extracted from the colonoscope using 1 of 4 techniques. Method I was the conventional method of pressing the suction valve button and retrieving the polyp through a trap. Method II involved removing the suction valve, covering the open suction valve cylinder with a finger. Method III used a Roth Net polyp retriever placed through the instrument channel. Method IV involved connecting a polyp trap to suction onto the instrument channel port. Fragmentation was defined as multiple pieces of the specimen in formalin, as grossly described by the pathologist. Alternative approaches (methods II, III, and IV) were all compared with the conventional method (method I). RESULTS: The method I fragmentation rate of polyps was 60.3% (123/204). Method II extraction reduced fragmentation to 43.0% (52/121, P = .003), proving that fragmentation occurs with passage through the suction valve channel. Method III had a lower fragmentation rate of 23.1% (6/26, P < .001). Method IV likewise showed a reduced fragmentation rate of 18.5% (5/27, P < .001). CONCLUSIONS: Polyp fragmentation is reduced by removal of the suction valve button. There is also a decrease in fragmentation rates in removing the polyp by connecting the polyp trap to the instrument port. Our study suggests that decreasing polyp fragmentation and improving pathology margin interpretability is possible through methods that extract polyps through the instrument port with currently available devices.

Alcohol Feeding in Mice Promotes Colonic Hyperpermeability and Changes in Colonic Organoid Stem Cell Fate.

BACKGROUND: Alcohol increases intestinal permeability to proinflammatory microbial products that promote liver disease, even after a period of sobriety. We sought to test the hypothesis that alcohol affects intestinal stem cells using an in vivo model and ex vivo organoids generated from jejunum and colon from mice fed chronic alcohol. METHODS: Mice were fed a control or an alcohol diet. Intestinal permeability, liver steatosis-inflammation, and stool short-chain fatty acids (SCFAs) were measured. Jejunum and colonic organoids and tissue were stained for stem cell, cell lineage, and apical junction markers with assessment of mRNA by PCR and RNA-seq. ChIP-PCR analysis was carried out for Notch1 using an antibody specific for acetylated histone 3. RESULTS: Alcohol-fed mice exhibited colonic (but not small intestinal) hyperpermeability, steatohepatitis, and decreased butyrate/total SCFA ratio in stool. Stem cell, cell lineage, and apical junction marker staining in tissue or organoids from jejunum tissue were not impacted by alcohol. Only chromogranin A (Chga) was increased in jejunum organoids by qPCR. However, colonic tissue and organoid staining exhibited an alcohol-induced significant decrease in cytokeratin 20+  (Krt20+) absorptive lineage enterocytes, a decrease in occludin and E-cadherin apical junction proteins, an increase in Chga, and an increase in the Lgr5 stem cell marker. qPCR revealed an alcohol-induced decrease in colonic organoid and tissue Notch1, Hes1, and Krt20 and increased Chga, supporting an alteration in stem cell fate due to decreased Notch1 expression. Colonic tissue ChIP-PCR revealed alcohol feeding suppressed Notch1 mRNA expression (via deacetylation of histone H3) and decreased Notch1 tissue staining. CONCLUSIONS: Data support a model for alcohol-induced colonic hyperpermeability via epigenetic effects on Notch1, and thus Hes1, suppression through a mechanism involving histone H3 deacetylation at the Notch1 locus. This decreased enterocyte and increased enteroendocrine cell colonic stem cell fate and decreased apical junctional proteins leading to hyperpermeability.

Advanced colonic neoplasia in the first degree relatives of colon cancer patients: A colonoscopy-based study.

We aimed to determine the risk of advanced neoplasms among a cohort of asymptomatic first degree relatives (FDRs) of patients with sporadic colorectal cancer (CRC) compared with matched controls. Data for patients with a diagnosis of CRC made between September 2013 and August 2014 were obtained from a population-based cancer registry system in Tehran. Screening colonoscopies were done for 342 FDRs and the findings were compared to those from 342 age- and gender-matched healthy controls without a family history of CRC. We reported the association as conditional Odds Ratio (OR) using Mantel Hazel and Logistic regression. The prevalence of advanced neoplasia was 13.2% among FDRs and 3.8% in controls (matched OR [mOR], 4.0, 95% confidence interval [CI], 2.1 - 7.6; p < 0.001). In FDRs aged 40-49 years, the prevalence of advanced neoplasia was significantly higher than in their matched controls (mOR, 6.8, 95% CI, 1.5-31.4; p = 0.01). Family history of CRC in at least one FDR was the strongest predictor of advanced neoplasia (adjusted OR, 4.0, 95% CI: 2.1-7.6; p < 0.001). The age of the index case at diagnosis did not predict the presence of advanced colonic neoplasms in their FDRs. Our study indicates a high risk of advanced neoplasia in FDRs of CRC cases, where only eight colonoscopies are needed to detect one advanced neoplasia. Our data suggest that all FDRs, regardless of the age of CRC diagnosis in their index case, should be considered for a targeted early screening.

Distinctive expression pattern of interleukin-17 cytokine family members in colorectal cancer.

Colorectal cancer (CRC) is one of the most common cancers in both genders. Even though interleukin (IL)-17A was shown to play an important role in intestinal tumourigenesis and CRC, other IL-17 family members were not studied well. We therefore studied the expression of IL-17 cytokine family members in CRC. Ten healthy colons and ten CRC mucosa were immunostained for IL-17B, IL-17C, IL-17E, and IL-17F, and their receptors IL-17RA, IL-17RB, and IL-17RC. Double immunofluorescence staining of the CRC mucosa was done for IL-17B with markers of neutrophils, endothelial cells, macrophages, T cells, mast cells, or fibroblasts. While IL-17B was increased in CRC with a strong presence both in the epithelial and stromal compartments, IL-17C showed different expression depending on the grade of differentiation and IL-17E remained unchanged. In contrast, IL-17F was decreased in CRC compared to healthy control. Colon epithelial cells stained positive for IL-17RA, IL-17RB, and IL-17RC in both healthy control and CRC. Neutrophils were the main source of IL-17B in the stroma. IL-17 family members demonstrated distinct expression patterns in CRC, suggesting a differential role exerted by each member in colon carcinogenesis.

Presence of small sessile serrated polyps increases rate of advanced neoplasia upon surveillance compared with isolated low-risk tubular adenomas.

BACKGROUND AND AIMS: The U.S. Multi-Society Task Force (USMSTF) stratifies patients with sessile serrated polyps (SSPs) without cytologic dysplasia of <10 mm in size as at low risk for metachronous advanced neoplasia and recommends management similar to low-risk conventional tubular adenomas. Evidence supporting the recommended surveillance interval for these low-risk SSPs is limited. We aimed to assess rates of metachronous advanced neoplasia based on the presence of an initial low-risk SSP compared with isolated low-risk tubular adenomas. METHODS: Colonoscopy data were retrieved for 2260 patients found to have an adenoma or SSP on pathology records between 2005 and 2011 at an academic medical center. The 788 patients who met study design criteria were stratified into 4 groups based on the presence of a high- or low-risk adenoma (HRA or LRA) and of a synchronous SSP on initial colonoscopy. The rates of advanced neoplasia at surveillance colonoscopy were then compared between groups. RESULTS: The rate of advanced neoplasia at surveillance in the LRA inclusive of SSP group (12/66, 18.2%) was greater than in the LRA without any SSP group (29/370, 7.8%; P = .019). The rate of advanced neoplasia at surveillance in patients with isolated low-risk SSP (10/56, 17.9%) remained significantly greater than those with isolated low-risk tubular adenomas (29/370, 7.8%; P = .024). The rate of advanced neoplasia upon surveillance in the LRA inclusive of SSP group (18.2%) was comparable with the rate observed in the index HRA without any SSP group (15.9%) (40/252, P = .709). CONCLUSIONS: The rate of advanced neoplasia upon surveillance in patients with initial low-risk SSPs is higher than in patients with initial isolated low-risk tubular adenomas and more similar to patients with initial high-risk tubular adenomas. These findings suggest that the rate of metachronous advanced neoplasia in patients with what are considered by USMSTF as "low-risk" SSPs is higher than in those without SSPs. Therefore, a surveillance interval that accounts for the presence of SSPs even in small lesions without cytologic dysplasia should be considered.

Prevalence of allergic rhinitis and asthma in patients with chronic rhinosinusitis and gastroesophageal reflux disease.

BACKGROUND: An association between chronic rhinosinusitis (CRS) and gastroesophageal reflux disease (GERD) has been previously reported; however, the underlying factors linking CRS and GERD remain to be elucidated. OBJECTIVE: To assess the association of GERD and CRS using prospective and retrospective approaches. METHODS: The retrospective study comprised a large cohort of CRS cases, whereas the prospective arm evaluated a series of CRS cases and controls. RESULTS: In the retrospective arm of the study, of the 1066 patients with CRS, 112 (10.5%) had GERD. Among patients with CRS, GERD was associated with higher body mass index, older age, and female sex. The odds ratios (ORs) for asthma and allergic rhinitis in the CRS group with GERD compared with the CRS group without GERD were 2.89 (95% confidence interval [CI], 1.905-4.389) and 2.021 (95% CI, 1.035-3.947). Furthermore, GERD was associated with a greater duration of CRS. Ninety patients with CRS and 81 controls were enrolled in the prospective arm of the study. In the CRS group, GERD was associated with asthma (OR, 4.77; 95% CI, 1.27-18.01). Patients with CRS and GERD had a longer duration and a younger age at onset of CRS. In controls, no association was found between GERD and asthma (OR, 0.67; 95% CI, 0.09-5.19) or allergic rhinitis (OR, 0.35; 95% CI, 0.05-2.59). CONCLUSION: Patients with CRS and GERD are more likely to have atopic conditions and asthma when compared with patients with CRS but without GERD. One of the potential explanations of this link is that comorbid GERD and atopic disease are potential risk factors for development of CRS.

Light/Dark Shifting Promotes Alcohol-Induced Colon Carcinogenesis: Possible Role of Intestinal Inflammatory Milieu and Microbiota.

BACKGROUND: Colorectal cancer (CRC) is associated with the modern lifestyle. Chronic alcohol consumption-a frequent habit of majority of modern societies-increases the risk of CRC. Our group showed that chronic alcohol consumption increases polyposis in a mouse mode of CRC. Here we assess the effect of circadian disruption-another modern life style habit-in promoting alcohol-associated CRC. METHOD: TS4Cre × adenomatous polyposis coli (APC)lox468 mice underwent (a) an alcohol-containing diet while maintained on a normal 12 h light:12 h dark cycle; or (b) an alcohol-containing diet in conjunction with circadian disruption by once-weekly 12 h phase reversals of the light:dark (LD) cycle. Mice were sacrificed after eight weeks of full alcohol and/or LD shift to collect intestine samples. Tumor number, size, and histologic grades were compared between animal groups. Mast cell protease 2 (MCP2) and 6 (MCP6) histology score were analyzed and compared. Stool collected at baseline and after four weeks of experimental manipulations was used for microbiota analysis. RESULTS: The combination of alcohol and LD shifting accelerated intestinal polyposis, with a significant increase in polyp size, and caused advanced neoplasia. Consistent with a pathogenic role of stromal tryptase-positive mast cells in colon carcinogenesis, the ratio of mMCP6 (stromal)/mMCP2 (intraepithelial) mast cells increased upon LD shifting. Baseline microbiota was similar between groups, and experimental manipulations resulted in a significant difference in the microbiota composition between groups. CONCLUSIONS: Circadian disruption by Light:dark shifting exacerbates alcohol-induced polyposis and CRC. Effect of circadian disruption could, at least partly, be mediated by promoting a pro-tumorigenic inflammatory milieu via changes in microbiota.