Region-specific Wnt signaling responses promote gastric polyp formation in patients with familial adenomatous polyposis.

Germline adenomatous polyposis coli (APC) mutation in patients with familial adenomatous polyposis (FAP) promotes gastrointestinal polyposis, including the formation of frequent gastric fundic gland polyps (FGPs). In this study, we investigated how dysregulated Wnt signaling promotes FGPs and why they localize to the corpus region of the stomach. We developed a biobank of FGP and surrounding nonpolyp corpus biopsies and organoids from patients with FAP for comparative studies. Polyp biopsies and polyp-derived organoids exhibited enhanced Wnt target gene expression. Polyp-derived organoids with intrinsically upregulated Wnt signaling showed poor tolerance to further induction, suggesting that high Wnt restricts growth. Targeted genomic sequencing revealed that most gastric polyps did not arise via APC loss of heterozygosity. Studies in genetic mouse models demonstrated that heterozygous Apc loss increased epithelial cell proliferation in the corpus but not the antrum, while homozygous Apc loss was not maintained in the corpus yet induced hyperproliferation in the antrum. Our findings suggest that heterozygous APC mutation in patients with FAP may be sufficient to drive polyp formation in the corpus region while subsequent loss of heterozygosity to further enhance Wnt signaling is not tolerated. This finding contextualizes the abundant yet benign nature of gastric polyps in FAP patient corpus compared with the rare, yet adenomatous polyps in the antrum.

Flexible fiber cholangioscope for detection of near-infrared fluorescence.

Video 1Flexible fiber cholangioscope for detection of near-infrared fluorescence.

Detection of Barrett's neoplasia with a near-infrared fluorescent heterodimeric peptide.

BACKGROUND: Esophageal adenocarcinoma (EAC) is a molecularly heterogeneous disease with poor prognosis that is rising rapidly in incidence. We aimed to demonstrate specific binding by a peptide heterodimer to Barrett's neoplasia in human subjects. METHODS: Peptide monomers specific for EGFR and ErbB2 were arranged in a heterodimer configuration and labeled with IRDye800. This near-infrared (NIR) contrast agent was topically administered to patients with Barrett's esophagus (BE) undergoing either endoscopic therapy or surveillance. Fluorescence images were collected using a flexible fiber accessory passed through the instrument channel of an upper gastrointestinal endoscope. Fluorescence images were collected from 31 BE patients. A deep learning model was used to segment the target (T) and background (B) regions. RESULTS: The mean target-to-background (T/B) ratio was significantly greater for high grade dysplasia (HGD) and EAC versus BE, low grade dysplasia (LGD), and squamous epithelium. At a T/B ratio of 1.5, sensitivity and specificity of 94.1 % and 92.6 %, respectively, were achieved for the detection of Barrett's neoplasia with an area under the curve of 0.95. No adverse events attributed to the heterodimer were found. EGFR and ErbB2 expression were validated in the resected specimens. CONCLUSIONS: This "first-in-human" clinical study demonstrates the feasibility of detection of early Barrett's neoplasia using a NIR-labeled peptide heterodimer.

Changes in Serum, Red Blood Cell, and Colonic Fatty Acids in a Personalized Omega-3 Fatty Acid Supplementation Trial.

This study evaluated changes in fatty acids from sera, red blood cells, and colonic biopsies from a phase Ib clinical trial of personalized ω-3 fatty acid dosing in 47 healthy volunteers. The trial aimed to reduce colonic prostaglandin E2 (PGE2), a pro-inflammatory product of arachidonic acid (AA) oxidation. The personalized doses ranged 2-10 grams/day (54% eicosapentaenoic acid, EPA, 24% other ω-3 fatty acids). In colon, increases in ω-3 highly unsaturated fatty acids (HUFA) and EPA:AA ratios each were correlated with decreases in PGE2. Changes in either colonic EPA:AA ratios or ω-3 HUFA were significantly correlated with changes in the same fatty acid measures in red blood cells or serum. The only blood-based measure significantly correlated with changes in colonic PGE2 was change in red blood cell ω-3 HUFA (ρ = -0.39), and the increase in red blood cell ω-3 HUFA was significantly greater in participants who had at least a median reduction in colonic PGE2 vs. those who did not. In summary, fatty acid changes in blood did reflect fatty acid changes in the colon, but additional factors will be needed for optimizing dosing models that seek to predict the anti-inflammatory effects of ω-3 fatty acids on the colon.

A Multi-Mineral Intervention to Modulate Colonic Mucosal Protein Profile: Results from a 90-Day Trial in Human Subjects.

The overall goal of this study was to determine whether Aquamin®, a calcium-, magnesium-, trace element-rich, red algae-derived natural product, would alter the expression of proteins involved in growth-regulation and differentiation in colon. Thirty healthy human subjects (at risk for colorectal cancer) were enrolled in a three-arm, 90-day interventional trial. Aquamin® was compared to calcium alone and placebo. Before and after the interventional period, colonic biopsies were obtained. Biopsies were evaluated by immunohistology for expression of Ki67 (proliferation marker) and for CK20 and p21 (differentiation markers). Tandem mass tag-mass spectrometry-based detection was used to assess levels of multiple proteins. As compared to placebo or calcium, Aquamin® reduced the level of Ki67 expression and slightly increased CK20 expression. Increased p21 expression was observed with both calcium and Aquamin®. In proteomic screen, Aquamin® treatment resulted in many more proteins being upregulated (including pro-apoptotic, cytokeratins, cell-cell adhesion molecules, and components of the basement membrane) or downregulated (proliferation and nucleic acid metabolism) than placebo. Calcium alone also altered the expression of many of the same proteins but not to the same extent as Aquamin®. We conclude that daily Aquamin® ingestion alters protein expression profile in the colon that could be beneficial to colonic health.

An Adaptive Bayesian Design for Personalized Dosing in a Cancer Prevention Trial.

INTRODUCTION: In biomarker-driven clinical trials, translational strategies typically involve moving findings from animal experiments to human trials. Typically, the translation is static, using a fixed model derived from animal experiments for the duration of the trial. Bayesian designs, capable of incorporating information external to the experiment, provide a dynamic translational strategy. This article demonstrates an example of such a dynamic Bayesian strategy in a clinical trial. METHODS: This study explored the effect of a personalized dose of fish oil for reducing prostaglandin E2, an inflammatory marker linked to colorectal cancer. A Bayesian design was implemented for the dose-finding algorithm that adaptively updated a dose-response model derived from a previously completed animal study during the clinical trial. In the initial stages of the trial, the dose-response model parameters were estimated from the rodent data. The model was updated following a Bayesian algorithm after data on every 10‒15 subjects were obtained until the model stabilized. Subjects were enrolled in the study between 2013 and 2015, and the data analysis was carried out in 2016. RESULTS: The 3 dosing models were used for groups of 16, 15, and 15 subjects. The mean target dose significantly decreased from 6.63 g/day (Model 1) to 4.06 g/day (Model 3) (p=0.001). Compared with the static strategy of dosing with a single model, the dynamic modeling reduced the dose significantly by about 1.38 g/day on average. CONCLUSIONS: A Bayesian design was effective in adaptively revising the dosing algorithm, resulting in a lower pill burden. TRIAL REGISTRATION: This study is registered at www.clinicaltrials.gov NCT01860352.

A Calcium-Rich Multimineral Intervention to Modulate Colonic Microbial Communities and Metabolomic Profiles in Humans: Results from a 90-Day Trial.

Aquamin is a calcium-, magnesium-, and multiple trace element-rich natural product with colon polyp prevention efficacy based on preclinical studies. The goal of this study was to determine the effects of Aquamin on colonic microbial community and attendant metabolomic profile. Thirty healthy human participants were enrolled in a 90-day trial in which Aquamin (delivering 800 mg of calcium per day) was compared with calcium alone or placebo. Before and after the intervention, colonic biopsies and stool specimens were obtained. All 30 participants completed the study without serious adverse event or change in liver and renal function markers. Compared with pretreatment values, intervention with Aquamin led to a reduction in total bacterial DNA (P = 0.0001) and a shift in the microbial community measured by thetaYC (θYC; P = 0.0087). Treatment with calcium also produced a decline in total bacteria, but smaller than seen with Aquamin, whereas no reduction was observed with placebo in the colon. In parallel with microbial changes, a reduction in total bile acid levels (P = 0.0375) and a slight increase in the level of the short-chain fatty acid (SCFA) acetate in stool specimens (P < 0.0001) from Aquamin-treated participants were noted. No change in bile acids or SCFAs was observed with calcium or placebo. We conclude that Aquamin is safe and tolerable in healthy human participants and may produce beneficial alterations in the colonic microbial community and the attendant metabolomic profile. Because the number of participants was small, the findings should be considered preliminary.

Increases in Colonic Bacterial Diversity after ω-3 Fatty Acid Supplementation Predict Decreased Colonic Prostaglandin E2 Concentrations in Healthy Adults.

BACKGROUND: The intestinal microbiome is an important determinant of inflammatory balance in the colon that may affect response to dietary agents. OBJECTIVE: This is a secondary analysis of a clinical trial, the Fish Oil Study, to determine whether interindividual differences in colonic bacteria are associated with variability in the reduction of colonic prostaglandin E2 (PGE2) concentrations after personalized supplementation with ω-3 (n-3) fatty acids. METHODS: Forty-seven healthy adults (17 men, 30 women, ages 26-75 y) provided biopsy samples of colonic mucosa and luminal stool brushings before and after personalized ω-3 fatty acid supplementation that was based on blood fatty acid responses. Samples were analyzed using 16S ribosomal RNA sequencing. The data analyses focused on changes in bacterial community diversity. Linear regression was used to evaluate factors that predict a reduction in colonic PGE2. RESULTS: At baseline, increased bacterial diversity, as measured by the Shannon and Inverse Simpson indexes in both biopsy and luminal brushing samples, was positively correlated with dietary fiber intakes and negatively correlated with fat intakes. Dietary supplementation with ω-3 fatty acids increased the Yue and Clayton community dis-similarity index between the microbiome in luminal brushings and colon biopsy samples post-supplementation (P = 0.015). In addition, there was a small group of individuals with relatively high Prevotella abundance who were resistant to the anti-inflammatory effects of ω-3 fatty acid supplementation. In linear regression analyses, increases in diversity of the bacteria in the luminal brushing samples, but not in the biopsy samples, were significant predictors of lower colonic PGE2 concentrations post-supplementation in models that included baseline PGE2, baseline body mass index, and changes in colonic eicosapentaenoic acid-to-arachidonic acid ratios. The changes in bacterial diversity contributed to 6-8% of the interindividual variance in change in colonic PGE2 (P = 0.001). CONCLUSIONS: Dietary supplementation with ω-3 fatty acids had little effect on intestinal bacteria in healthy humans; however, an increase in diversity in the luminal brushings significantly predicted reductions in colonic PGE2. This trial was registered at www.clinicaltrials.gov as NCT01860352.

Higher baseline expression of the PTGS2 gene and greater decreases in total colonic fatty acid content predict greater decreases in colonic prostaglandin-E2 concentrations after dietary supplementation with ω-3 fatty acids.

This study evaluated whether mRNA expression of major genes regulating formation of prostaglandin (PG)E2 in the colon and colonic fatty acid concentrations are associated with the reduction in colonic mucosal PGE2 after dietary supplementation with omega-3 (ω-3) fatty acids. Supplementation with ω-3 fatty acids was done for 12 weeks using personalized dosing that was expected to reduce colonic PGE2 by 50%. In stepwise linear regression models, the ω-3 fatty acid dose and baseline BMI explained 16.1% of the inter-individual variability in the fold change of colonic PGE2 post-supplementation. Increases in mRNA gene expression after supplementation were, however, modest and were not associated with changes in PGE2. When baseline expression of PTGS1, PTGS2 and HPGD genes was included in the linear regression model containing dose and BMI, only PTGS2, the gene coding for the inducible form cyclooxygenase, was a significant predictor. Higher relative expression of PTGS2 predicted greater decreases in colonic PGE2, accounting for an additional 13.6% of the inter-individual variance. In the final step of the regression model, greater decreases in total colonic fatty acid concentrations predicted greater decreases in colonic PGE2, contributing to an additional 18.7% of the variance. Overall, baseline BMI, baseline expression of PTGS2 and changes in colonic total fatty acids together accounted for 48% of the inter-individual variability in the change in colonic PGE2. This is consistent with biochemical data showing that fatty acids which are not substrates for cyclooxygenases can activate cyclooxygenase-2 allosterically. Further clinical trials are needed to elucidate the factors that regulate the fatty acid milieu of the human colon and how this interacts with key lipid metabolizing enzymes. Given the central role of PGE2 in colon carcinogenesis, these pathways may also impact on colon cancer prevention by other dietary and pharmacological approaches.

Calcium-Induced Differentiation of Human Colon Adenomas in Colonoid Culture: Calcium Alone versus Calcium with Additional Trace Elements.

Previous murine studies have demonstrated that dietary Aquamin, a calcium-rich, multi-mineral natural product, suppressed colon polyp formation and transition to invasive tumors more effectively than calcium alone when provided over the lifespan of the animals. In the current study, we compared calcium alone to Aquamin for modulation of growth and differentiation in human colon adenomas in colonoid culture. Colonoids established from normal colonic tissue were examined in parallel. Both calcium alone at 1.5 mmol/L and Aquamin (provided at 1.5 mmol/L calcium) fostered differentiation in the adenoma colonoid cultures as compared with control (calcium at 0.15 mmol/L). When Aquamin was provided at an amount delivering 0.15 mmol/L calcium, adenoma differentiation also occurred, but was not as complete. Characteristic of colonoids undergoing differentiation was a reduction in the number of small, highly proliferative buds and their replacement by fewer but larger buds with smoother surface. Proliferation marker (Ki67) expression was reduced and markers of differentiation (CK20 and occludin) were increased along with E-cadherin translocalization to the cell surface. Additional proteins associated with differentiation/growth control [including histone-1 family members, certain keratins, NF2 (merlin), olfactomedin-4 and metallothioneins] were altered as assessed by proteomics. Immunohistologic expression of NF2 was higher with Aquamin as compared with calcium at either concentration. These findings support the conclusions that (i) calcium (1.5 mmol/L) has the capacity to modulate growth and differentiation in large human colon adenomas and (ii) Aquamin delivering 0.15 mmol/L calcium has effects on proliferation and differentiation not observed when calcium is used alone at this concentration. Cancer Prev Res; 11(7); 413-28. ©2018 AACR.

Spatial Variation of the Native Colon Microbiota in Healthy Adults.

The microbiome has been implicated in the development of colorectal cancer and inflammatory bowel diseases. The specific traits of these diseases vary along the axis of the digestive tract. Further, variation in the structure of the gut microbiota has been associated with both diseases. We profiled the microbiota of the healthy proximal and distal mucosa and lumen to better understand how bacterial populations vary along the colon. We used a two-colonoscope approach to sample proximal and distal mucosal and luminal contents from the colons of 20 healthy subjects that had not undergone any bowel preparation procedure. The biopsies and home-collected stool were subjected to 16S rRNA gene sequencing, and random forest classification models were built using taxa abundance and location to identify microbiota specific to each site. The right mucosa and lumen had the most similar community structures of the five sites we considered from each subject. The distal mucosa had higher relative abundance of Finegoldia, Murdochiella, Peptoniphilus, Porphyromonas, and Anaerococcus The proximal mucosa had more of the genera Enterobacteriaceae, Bacteroides, and Pseudomonas The classification model performed well when classifying mucosal samples into proximal or distal sides (AUC = 0.808). Separating proximal and distal luminal samples proved more challenging (AUC = 0.599), and specific microbiota that differentiated the two were hard to identify. By sampling the unprepped colon, we identified distinct bacterial populations native to the proximal and distal sides. Further investigation of these bacteria may elucidate if and how these groups contribute to different disease processes on their respective sides of the colon. Cancer Prev Res; 11(7); 393-402. ©2018 AACR.

Colonic Mucosal Bacteria Are Associated with Inter-Individual Variability in Serum Carotenoid Concentrations.

BACKGROUND: Relatively high serum carotenoid levels are associated with reduced risks of chronic diseases, but inter-individual variability in serum carotenoid concentrations is modestly explained by diet. The bacterial community in the colon could contribute to the bioaccessibility of carotenoids by completing digestion of plant cells walls and by modulating intestinal permeability. OBJECTIVE: To evaluate whether colonic bacterial composition is associated with serum and colon carotenoid concentrations. DESIGN: The study was a randomized dietary intervention trial in healthy individuals who were at increased risk of colon cancer. Colon mucosal biopsy samples were obtained before and after 6 months of intervention without prior preparation of the bowels. PARTICIPANTS/SETTING: Participants were recruited from Ann Arbor, MI, and nearby areas from July 2007 to November 2010. Biopsy data were available from 88 participants at baseline and 82 participants after 6 months. METHODS: Study participants were randomized to counseling for either a Mediterranean diet or a Healthy Eating diet for 6 months. RESULTS: At baseline, bacterial communities in biopsy samples from study participants in the highest vs the lowest tertile of total serum carotenoid levels differed by several parameters. Linear discriminant analysis effect size identified 11 operational taxonomic units that were significantly associated with higher serum carotenoid levels. In linear regression analyses, three of these accounted for an additional 12% of the variance in serum total carotenoid concentrations after including body mass index, smoking, and dietary intakes in the model. These factors together explained 36% of the inter-individual variance in serum total carotenoid concentrations. The bacterial community in the colonic mucosa, however, was resistant to change after dietary intervention with either a Mediterranean diet or Healthy Eating diet, each of which doubled fruit and vegetable intakes. CONCLUSIONS: The colonic mucosal bacterial community was associated with serum carotenoid concentrations at baseline but was not appreciably changed by dietary intervention.

The Anti-inflammatory Effect of Personalized Omega-3 Fatty Acid Dosing for Reducing Prostaglandin E2 in the Colonic Mucosa Is Attenuated in Obesity.

This clinical trial developed a personalized dosing model for reducing prostaglandin E2 (PGE2) in colonic mucosa using ω-3 fatty acid supplementation. The model utilized serum eicosapentaenoic acid (EPA, ω-3):arachidonic acid (AA, ω-6) ratios as biomarkers of colonic mucosal PGE2 concentration. Normal human volunteers were given low and high ω-3 fatty acid test doses for 2 weeks. This established a slope and intercept of the line for dose versus serum EPA:AA ratio in each individual. The slope and intercept was utilized to calculate a personalized target dose that was given for 12 weeks. This target dose was calculated on the basis of a model, initially derived from lean rodents, showing a log-linear relationship between serum EPA:AA ratios and colonic mucosal PGE2 reduction. Bayesian methods allowed addition of human data to the rodent model as the trial progressed. The dosing model aimed to achieve a serum EPA:AA ratio that is associated with a 50% reduction in colonic PGE2 Mean colonic mucosal PGE2 concentrations were 6.55 ng/mg protein (SD, 5.78) before any supplementation and 3.59 ng/mg protein (SD, 3.29) after 12 weeks of target dosing. In secondary analyses, the decreases in PGE2 were significantly attenuated in overweight and obese participants. This occurred despite a higher target dose for the obese versus normal weight participants, as generated by the pharmacodynamic predictive model. Large decreases also were observed in 12-hydroxyicosatetraenoic acids, and PGE3 increased substantially. Future biomarker-driven dosing models for cancer prevention therefore should consider energy balance as well as overall eicosanoid homeostasis in normal tissue. Cancer Prev Res; 10(12); 729-37. ©2017 AACR.

A Multicenter Study of a Fluorescence In Situ Hybridization Probe Set for Diagnosing High-Grade Dysplasia and Adenocarcinoma in Barrett's Esophagus.

BACKGROUND AND AIMS: Preliminary single-institution data suggest that fluorescence in situ hybridization (FISH) may be useful for detecting high-grade dysplasia (HGD) and esophageal adenocarcinoma (EA) in patients with Barrett's esophagus (BE). This multicenter study aims to validate the measurement of polysomy (gain of at least two loci) by FISH as a way to discriminate degrees of dysplasia in BE specimens. METHODS: Tissue specimens were collected from four different hospitals and read by both the local pathology department ("Site diagnosis") and a single central pathologist ("Review diagnosis") at a separate institution. The specimens then underwent FISH analysis using probes 8q24 (MYC), 9p21 (CDKN2A), 17q12 (ERBB2), and 20q13 (ZNF217) for comparison. A total of 46 non-BE, 42 non-dysplastic specialized intestinal metaplasia (SIM), 23 indefinite-grade dysplasia (IGD), 10 low-grade dysplasia (LGD), 29 HGD, and 42 EA specimens were analyzed. RESULTS: We found that polysomy, as detected by FISH, was the predominant chromosomal abnormality present as dysplasia increased. Polysomy was also the best predictor for the presence of dysplasia or EA when comparing its area under the curve to that of other FISH abnormalities. We observed that if at least 10% of cells had polysomy within a specimen, the FISH probe was able to differentiate between EA/HGD and the remaining pathologies with a sensitivity of 80% and a specificity of 88%. CONCLUSIONS: This study demonstrates that using FISH to determine the percentage of cells with polysomy can accurately and objectively aid in the diagnosis of HGD/EA in BE specimens.

NOTCH1 and NOTCH2 regulate epithelial cell proliferation in mouse and human gastric corpus.

The Notch signaling pathway is known to regulate stem cells and epithelial cell homeostasis in gastrointestinal tissues; however, Notch function in the corpus region of the stomach is poorly understood. In this study we examined the consequences of Notch inhibition and activation on cellular proliferation and differentiation and defined the specific Notch receptors functioning in the mouse and human corpus. Notch pathway activity was observed in the mouse corpus epithelium, and gene expression analysis revealed NOTCH1 and NOTCH2 to be the predominant Notch receptors in both mouse and human. Global Notch inhibition for 5 days reduced progenitor cell proliferation in the mouse corpus, as well as in organoids derived from mouse and human corpus tissue. Proliferation effects were mediated through both NOTCH1 and NOTCH2 receptors, as demonstrated by targeting each receptor alone or in combination with Notch receptor inhibitory antibodies. Analysis of differentiation by marker expression showed no change to the major cell lineages; however, there was a modest increase in the number of transitional cells coexpressing markers of mucous neck and chief cells. In contrast to reduced proliferation after pathway inhibition, Notch activation in the adult stomach resulted in increased proliferation coupled with reduced differentiation. These findings suggest that NOTCH1 and NOTCH2 signaling promotes progenitor cell proliferation in the mouse and human gastric corpus, which is consistent with previously defined roles for Notch in promoting stem and progenitor cell proliferation in the intestine and antral stomach. NEW & NOTEWORTHY: Here we demonstrate that the Notch signaling pathway is essential for proliferation of stem cells in the mouse and human gastric corpus. We identify NOTCH1 and NOTCH2 as the predominant Notch receptors expressed in both mouse and human corpus and show that both receptors are required for corpus stem cell proliferation. We show that chronic Notch activation in corpus stem cells induces hyperproliferation and tissue hypertrophy, suggesting that Notch may drive gastric tumorigenesis.

Detection of Sessile Serrated Adenomas in the Proximal Colon Using Wide-Field Fluorescence Endoscopy.

BACKGROUND & AIMS: Many cancers in the proximal colon develop via from sessile serrated adenomas (SSAs), which have flat, subtle features that are difficult to detect with conventional white-light colonoscopy. Many SSA cells have the V600E mutation in BRAF. We investigated whether this feature could be used with imaging methods to detect SSAs in patients. METHODS: We used phage display to identify a peptide that binds specifically to SSAs, using subtractive hybridization with HT29 colorectal cancer cells containing the V600E mutation in BRAF and Hs738.St/Int cells as a control. Binding of fluorescently labeled peptide to colorectal cancer cells was evaluated with confocal fluorescence microscopy. Rats received intra-colonic 0.0086 mg/kg, 0.026 mg/kg, or 0.86 mg/kg peptide or vehicle and morbidity, mortality, and injury were monitored twice daily to assess toxicity. In the clinical safety study, fluorescently labeled peptide was topically administered, using a spray catheter, to the proximal colon of 25 subjects undergoing routine outpatient colonoscopies (3 subjects were given 2.25 µmol/L and 22 patients were given 76.4 µmol/L). We performed blood cell count, chemistry, liver function, and urine analyses approximately 24 hours after peptide administration. In the clinical imaging study, 38 subjects undergoing routine outpatient colonoscopies, at high risk for colorectal cancer, or with a suspected unresected proximal colonic polyp, were first evaluated by white-light endoscopy to identify suspicious regions. The fluorescently labeled peptide (76.4 µmol/L) was administered topically to proximal colon, unbound peptide was washed away, and white-light, reflectance, and fluorescence videos were recorded digitally. Fluorescence intensities of SSAs were compared with those of normal colonic mucosa. Endoscopists resected identified lesions, which were analyzed histologically by gastrointestinal pathologists (reference standard). We also analyzed the ability of the peptide to identify SSAs vs adenomas, hyperplastic polyps, and normal colonic mucosa in specimens obtained from the tissue bank at the University of Michigan. RESULTS: We identified the peptide sequence KCCFPAQ and measured an apparent dissociation constant of Kd = 72 nM and an apparent association time constant of K = 0.174 min-1 (5.76 minutes). During fluorescence imaging of patients during endoscopy, regions of SSA had 2.43-fold higher mean fluorescence intensity than that for normal colonic mucosa. Fluorescence labeling distinguished SSAs from normal colonic mucosa with 89% sensitivity and 92% specificity. The peptide had no observed toxic effects in animals or patients. In the analysis of ex vivo specimens, peptide bound to SSAs had significantly higher mean fluorescence intensity than to hyperplastic polyps. CONCLUSIONS: We have identified a fluorescently labeled peptide that has no observed toxic effects in animals or humans and can be used for wide-field imaging of lesions in the proximal colon. It distinguishes SSAs from normal colonic mucosa with 89% sensitivity and 92% specificity. This targeted imaging method might be used in early detection of premalignant serrated lesions during routine colonoscopies. ClinicalTrials.gov ID: NCT02156557.

Colonic Saturated Fatty Acid Concentrations and Expression of COX-1, but not Diet, Predict Prostaglandin E2 in Normal Human Colon Tissue.

Prostaglandin E2 (PGE2) in the colon is a pro-inflammatory mediator that is associated with increased risk of colon cancer. In this study, expression of genes in the PGE2 pathway were quantified in colon biopsies from a trial of a Mediterranean versus a Healthy Eating diet in 113 individuals at high risk for colon cancer. Colon biopsies were obtained before and after 6 months of intervention. Quantitative, real-time PCR was used to measure mRNA expression of prostaglandin H synthases (PTGS1 and 2), prostaglandin E synthases (PTGES1 and 3), prostaglandin dehydrogenase (HPGD), and PGE2 receptors (PTGER2, PTGER4). The most highly expressed genes were HPGD and PTGS1. In multivariate linear regression models of baseline data, both colon saturated fatty acid concentrations and PTGS1 expression were significant, positive predictors of colon PGE2 concentrations after controlling for nonsteroidal anti-inflammatory drug use, gender, age, and smoking status. The effects of dietary intervention on gene expression were minimal with small increases in expression noted for PTGES3 in both arms and in PTGER4 in the Mediterranean arm. These results indicate that short-term dietary change had little effect on enzymes in the prostaglandin pathway in the colon and other factors, such as differences in fatty acid metabolism, might be more influential.

Multimodal endoscope can quantify wide-field fluorescence detection of Barrett's neoplasia.

BACKGROUND AND STUDY AIMS: To demonstrate the clinical use of a multimodal endoscope with a targeted fluorescently labeled peptide for quantitative detection of Barrett's neoplasia. PATIENTS AND METHODS: We studied 50 patients with Barrett's esophagus using a prototype multimodal endoscope with a fluorescently labeled peptide. Co-registered fluorescence and reflectance images were converted to ratios to correct for differences in distance and geometry over the image field of view. The ratio images were segmented using a unique threshold that maximized the variance between high and low intensities to localize regions of high grade dysplasia (HGD) and esophageal adenocarcinoma (EAC). RESULTS: Early neoplasia (HGD and EAC) was identified with 94 % specificity and 96 % positive predictive value at a threshold of 1.49. The mean results for HGD and EAC were significantly greater than those for squamous/Barrett's esophagus and low grade dysplasia by one-way analysis of variance (ANOVA). The receiver operator characteristic curve for detection of early neoplasia had an area under the curve of 0.884. No adverse events associated with the endoscope or peptide were found. CONCLUSION: A multimodal endoscope can quantify fluorescence images from targeted peptides to localize early Barrett's neoplasia. (ClinicalTrials.gov number NCT01630798.).