Incomplete Intestinal Metaplasia of the Stomach Is more Related to Bile Reflux than Chronic Gastritis.

OBJECTIVE: Incomplete intestinal metaplasia (IIM) of the stomach is associated with higher risk of progression to dysplasia and gastric cancer than complete intestinal metaplasia (CIM). Whether the causative factors underlying IIM are different from those underlying CIM is currently unknown. In a recent study, bile acids were found to induce gastric intestinal metaplasia (IM) in mice by activating STAT3 signaling and accelerated the development of dysplasia. The aim of this study was to determine whether there are differences in associations between IIM and CIM and clinicopathologic features known to be associated with intestinal metaplasia, bile reflux, and activated STAT3. METHODS: Fifty-two consecutive gastric biopsies with IM were examined for the type of metaplasia, presence of inflammation, and Helicobacter pylori (H. pylori) status. Immunohistochemical staining was performed for phospho-STAT3 (p-STAT3) and evaluated by image analysis. The type of IM was then correlated with relevant clinicopathologic variables and p-STAT3 expression. RESULTS: Seven cases had IIM only, 31 had CIM only, and 14 had both CIM and IIM (CIIM). Significantly fewer cases with IIM had chronic gastritis than either CIM or CIIM (43%, 93%, 79%, respectively, p=0.005). H. pylori was not detected in any of the IIM cases but was positive in 29% of CIM and 29% of CIIM. Fifty-seven percent of patients with IIM had a history of cholecystectomy compared to 25% of those with CIM and 23% of those with CIIM. The mean BMI was 32.3 kg/m2 for patients with IIM compared to 28 kg/m2 for those with CIM and 31.2 kg/m2 for those with CIIM. Median p-STAT3 for biopsies with was IIM was 6.36 compared to 3.54 for CIM and 6.27 for CIIM. Reactive gastropathy was present in 57% of biopsies with IIM, 39% of CIM and 50% of CIIM. CONCLUSION: In contrast to CIM, IIM is significantly less likely to be associated with chronic gastritis. CIIM also tended to be less associated with H. pylori infection and more associated with reactive gastropathy, history of cholecystectomy, higher BMI, and higher median p-STAT3. These results tend to suggest that IIM is probably more likely to be associated with bile reflux than H. pylori-associated gastritis. Larger studies are needed to confirm these findings.Presented in part at Digestive Disease Week 2023, Chicago, IL, May 6, 2023.

A Common Infection in a Highly Atypical Patient: Hematochezia From a Cytomegalovirus Colonic Ulcer in a Young and Healthy Immunocompetent Patient.

Gastrointestinal (GI) cytomegalovirus (CMV) infections are far more common in immunocompromised as opposed to immunocompetent patients. Immunocompetent patients who develop GI tract CMV infections are typically older with medical comorbidities. As such, descriptions of GI CMV infections in younger immunocompetent patients are lacking. Here, we present a case of a GI CMV infection in a young and healthy immunocompetent patient. A 41-year-old male with hyperlipidemia and hypothyroidism presented with painless, intermittent hematochezia. He denied changes in bowel habits or appetite, abdominal pain, fevers, chills, fatigue, or weight loss. His history was pertinent for insertive and receptive intercourse with one male partner. Medications were emtricitabine/tenofovir for pre-exposure prophylaxis, levothyroxine, and atorvastatin. A colonoscopy revealed a cecal ulcer surrounded by nodular-appearing mucosa that felt firm and friable when biopsied. The remaining colon and terminal ileum were normal. There was no diverticulosis or hemorrhoids. Pathology was positive for CMV. A subsequent serological evaluation revealed a normal complete blood count and comprehensive metabolic panel. Tests for human immunodeficiency virus, syphilis, viral hepatitis, chlamydia, and gonorrhea were negative. He was treated with valganciclovir 900 mg twice daily for 21 days. A subsequent test for CMV deoxyribonucleic acid polymerase chain was negative. Hematochezia resolved. A repeat colonoscopy revealed normal mucosa in the cecum. GI CMV infections in immunocompetent patients are rare and typically occur in older patients with medical comorbidities. Further, such case reports are needed to inform clinicians about risk factors and the presentation of GI CMV infections in young healthy immunocompetent patients.

Overexpression of Gremlin1 in Crohn's Disease-Associated Bowel Strictures.

OBJECTIVE: One of the most serious complications of Crohn's disease is intestinal strictures that may lead to bowel obstruction. Understanding the underlying mechanisms of stricture formation is essential in order to develop more effective nonsurgical prevention and treatment modalities. The aim of this pilot study was to determine whether Gremlin1, a protein implicated in fibrogenesis and smooth muscle proliferation, is overexpressed in Crohn's-associated bowel strictures. METHODS: Paired sections from three strictured and non-strictured surgically resected bowel from patients with Crohn's disease were evaluated for Gremlin1 expression by immunohistochemistry. RESULTS: Strictured areas from all three specimens showed strong Gremlin1 staining in the hypertrophic muscularis mucosae area compared to no staining in the mucosa or muscularis propria in the same sections and in contrast to sections from non-strictured areas which were negative. CONCLUSIONS: This short report is the first to describe the overexpression of Gremlin1 in the hypertrophied muscularis mucosae of strictured small intestine from patients with Crohn's disease. Additional studies are needed to elucidate the potential role of Gremlin1 in the etiopathogenesis of Crohn's disease strictures, and to investigate whether targeting Gremlin1 may be an option for preventing or treating strictures in patients with Crohn's disease.

Colonic Eosinophilia: Clinicopathologic Study of Paired Right and Left Colon Biopsies from 276 Patients.

OBJECTIVE: This study evaluated differences in eosinophil (Eos) count in the right colon (RC) and left colon (LC) relative to known clinical and pathologic features. METHODS: H&E slides from 276 subjects with biopsies taken from both RC and LC were reviewed. Eos/mm2 were counted in the area with highest concentration then correlated with clinical and pathologic findings for RC and LC. RESULTS: There were higher numbers of Eos/mm2 in RC than in LC (mean 177 vs 122, respectively p<0.0001), and there was significant positive correlation between Eos numbers in the two locations (r=0.57, p<0.001). In RC, the mean Eos/mm2 was 242 with active chronic colitis, 195 with inactive chronic colitis, 160 in microscopic colitis, 144 in quiescent IBD, and 142 with normal histology (p<0.001), and was higher in males (204 vs 164, p=0.022). In LC, mean Eos/mm2 was 186 with active chronic colitis, 168 with inactive chronic colitis, 154 in microscopic colitis, 82 in quiescent IBD, and 84 with normal histology (p<0.001), and was higher in males (154 vs 107, p<0.001). In biopsies with normal histology, RC showed higher mean Eos/mm2 in Asian patients (228 vs 139, p=0.019), and patients with history of UC (205 vs 136, p=0.004), but was not significantly different in patients with or without irritable bowel syndrome with diarrhea (IBS-D) or history of Crohn's disease (CD). In LC the mean Eos/mm2 was higher in males (102 vs 77, p=0.036), and history of CD (117 vs 78, p=0.007), but was not significantly different in patients with or without IBS-D or history of UC. The number of Eos/mm2 was greater in biopsies performed in the summer than during other seasons of the year. CONCLUSION: The mean number of Eos/mm2 in colorectal biopsies varies significantly by location, histopathologic changes, clinical diagnosis, season, gender and ethnicity. Of particular interest is the association between high Eos/mm2 in RC biopsies with otherwise normal histology and clinical history of UC, and in LC biopsies with clinical history of CD. Additional larger and prospective studies that include normal healthy volunteers are needed to establish a reliable cutoff for the histopathologic diagnosis of eosinophilic colitis, taking into consideration the biopsy site within the colon and rectum, as well as patient gender and ethnicity.Presented in part at the annual American College of Gastroenterology meeting, San Antonio, TX October 2019.

Collagenous Gastritis: An Atypical Presentation of a Rare Disease.

Collagenous gastritis is a rare inflammatory condition of unknown etiology defined histologically by subepithelial deposition of collagen bands ≥ 10 µm in the lamina propria. Adults typically present with diarrhea, often attributed to concurrent collagenous sprue or collagenous colitis. Children more commonly present with abdominal pain and anemia, with inflammation typically limited to the stomach. Herein, we present a case of collagenous gastritis in a 38-year-old female with a history of iron deficiency and hypothalamic amenorrhea who presented with a one-year history of microcytic anemia. Celiac disease panel, Helicobacter pylori testing, and anti-parietal cell and intrinsic factor antibodies were negative. Esophagogastroduodenoscopy revealed diffusely erythematous and nodular gastric mucosa in the antrum and pylorus. Biopsy from the gastric body showed complete loss of oxyntic glands and deposition of a thick band of collagen under the surface epithelium infiltrated by a few eosinophils, consistent with collagenous gastritis with severe atrophy. She was treated with omeprazole 40 mg daily for six weeks and iron supplementation. Our patient's symptoms and endoscopic findings are consistent with previously described pediatric, but not adult, cases of collagenous gastritis, yielding insight into the variable clinical presentation of this rare disease.

Expression of p-STAT3 and c-Myc correlates with P2-HNF4α expression in nonalcoholic fatty liver disease (NAFLD).

We studied the expression of two hepatocyte nuclear factor 4 alpha (HNF4α) isoforms, p-STAT3. and c-Myc in 49 consecutive liver biopsies with nonalcoholic fatty liver disease (NAFLD) using immunohistochemistry. All 49 biopsies (100%) were positive for nuclear expression of P1-HNF4α. Twenty-eight (57%) cases were positive for P2-HNF4α, 6 (12%) were positive for p-STAT3 and 5 (10%) were positive for c-Myc. All 6 (100%) p-STAT3-positive cases were also positive for P2-HNF4α (p = 0.03). p-STAT3-positive cases were more likely to be positive for c-Myc (67% vs. 2%, p = 0.0003). Four cases were positive for P2-HNF4α, p-STAT3 and c-Myc. p-STAT3 expression was associated with hypertension (p = 0.037). All c-Myc positive biopsies were from patients with obesity, diabetes and hypertension. Only c-Myc expression was associated with advanced fibrosis; three (60%) of the c-Myc positive cases were associated with advanced fibrosis in contrast to 7 (10%) of the 44 c-Myc negative cases (p = 0.011). Based on these results, we hypothesize with the following sequence of events with progression of NAFLD: P2-HNF4α expression is followed by expression of p-STAT3 which in turn is followed by the expression of c-Myc. Additional larger studies are needed to confirm these findings.

Hepatic circadian and differentiation factors control liver susceptibility for fatty liver disease and tumorigenesis.

Hepatocellular carcinoma (HCC) is a leading cause of cancer deaths, and the most common primary liver malignancy to present in the clinic. With the exception of liver transplant, treatment options for advanced HCC are limited, but improved tumor stratification could open the door to new treatment options. Previously, we demonstrated that the circadian regulator Aryl Hydrocarbon-Like Receptor Like 1 (ARNTL, or Bmal1) and the liver-enriched nuclear factor 4 alpha (HNF4α) are robustly co-expressed in healthy liver but incompatible in the context of HCC. Faulty circadian expression of HNF4α- either by isoform switching, or loss of expression- results in an increased risk for HCC, while BMAL1 gain-of-function in HNF4α-positive HCC results in apoptosis and tumor regression. We hypothesize that the transcriptional programs of HNF4α and BMAL1 are antagonistic in liver disease and HCC. Here, we study this antagonism by generating a mouse model with inducible loss of hepatic HNF4α and BMAL1 expression. The results reveal that simultaneous loss of HNF4α and BMAL1 is protective against fatty liver and HCC in carcinogen-induced liver injury and in the "STAM" model of liver disease. Furthermore, our results suggest that targeting Bmal1 expression in the absence of HNF4α inhibits HCC growth and progression. Specifically, pharmacological suppression of Bmal1 in HNF4α-deficient, BMAL1-positive HCC with REV-ERB agonist SR9009 impairs tumor cell proliferation and migration in a REV-ERB-dependent manner, while having no effect on healthy hepatocytes. Collectively, our results suggest that stratification of HCC based on HNF4α and BMAL1 expression may provide a new perspective on HCC properties and potential targeted therapeutics.

Pancreatic stromal Gremlin 1 expression during pancreatic tumorigenesis.

Chronic pancreatitis (CP) is a major risk factor of pancreatic ductal adenocarcinoma (PDAC). How CP promotes pancreatic oncogenesis remains unclear. A characteristic feature of PDAC is its prominent desmoplasia in the tumor microenvironment, composed of activated fibroblasts and macrophages. Macrophages can be characterized as M1 or M2, with tumor-inhibiting or -promoting functions, respectively. We reported that Gremlin 1 (GREM1), a key pro-fibrogenic factor, is upregulated in the stroma of CP. The current study aimed to investigate the expression of GREM1 and correlation between GREM1 and macrophages within the pancreas during chronic inflammation and the development of PDAC. By mRNA in situ hybridization, we detected GREM1 mRNA expression within α-smooth muscle actin (SMA)-positive fibroblasts of the pancreatic stroma. These designated FibroblastsGrem1+ marginally increased from CP to pancreatic intraepithelial neoplasia (PanIN) and PDAC. Within PDAC, FibroblastsGrem1+ increased with higher pathological tumor stages and in a majority of PDAC subtypes screened. Additionally, FibroblastsGrem1+ positively correlated with total macrophages (MacCD68+) and M2 macrophages (M2CD163+) in PDAC. To begin exploring potential molecular links between FibroblastsGrem1+ and macrophages in PDAC, we examined the expression of macrophage migration inhibitory factor (MIF), an endogenous counteracting molecule of GREM1 and an M1 macrophage promoting factor. By IHC staining of MIF, we found MIF to be expressed by tumor cells, positively correlated with GREM1; by IHC co-staining, we found MIF to be negatively correlated with M2CD163+ expression. Our findings suggest that GREM1 expression by activated fibroblasts may promote PDAC development, and GREM1/MIF may play an important role in macrophage phenotype.

Alterations in MAdCAM1-Positive Mucosal Capillaries and Integrin a4b7-Positive Lymphocytes in Crohn's Disease Treated with Anti-TNFα Biologics.

OBJECTIVE: To elucidate the reasons for the decreased effectiveness of Vedolizumab (VDZ) treatment in patients with Crohn's disease (CD) previously treated (CD-T) with anti-TNF-α biologics. METHODS: Immunohistochemical staining was performed on sections of formalin-fixed paraffin-embedded ileocolonic biopsies using antibodies for the mucosal addressin molecule (MAdCAM-1) and Etrolizumab. RESULTS: The mean number of MAdCAM-1 positive capillaries (MAdCAM-1-C) was 3 in controls, 8.5 in CD, 5.37 in CD-T, 5.7 in ulcerative colitis (UC), and 3.1 in lymphocytic colitis (LC) (p=0.0032). When all biopsies with inflammatory bowel disease (IBD) in this series were considered together, the number of MAdCAM-1-C increased with an increased histologic activity score (HAS) (p<0.001). The mean MAd-CAM-1-C was lower in CD-T than CD (5.37 vs. 8.5, p=0.0362), even in cases with high HAS (6.46 vs. 9.5, p=0.073). Two of 6 (33%) controls, 4 of 6 (67%) CD, 9 of 16 (56%) CD-T, 6 of 7 (86%) UC, and 0 of 8 (0%) LC showed Etrolizumab-positive lymphocytes (E-Ly, p=0.0106). IBD biopsies positive for E-Ly were associated with higher HAS (p=0.0546). MAdCAM-1-C was heterogenous in some IBD cases. CONCLUSIONS: Our results suggest that treatment with anti-TNF-α reduces the number of MAdCAM-1-C in CD, even in biopsies with high HAS. This suggests that high inflammation in such cases obviously failed to respond to anti-TNF-α, may be less dependent on the migration of a4b7-lymphocytes to the inflamed mucosa, and therefore may not optimally respond to VDZ treatment.Presented in part at the Digestive Diseases Week meeting, San Diego, CA, May 2019. Supported by Takeda Pharmaceuticals.

Telomere dysfunction instigates inflammation in inflammatory bowel disease.

Inflammatory bowel disease (IBD) is a chronic inflammatory condition driven by diverse genetic and nongenetic programs that converge to disrupt immune homeostasis in the intestine. We have reported that, in murine intestinal epithelium with telomere dysfunction, DNA damage-induced activation of ataxia-telangiectasia mutated (ATM) results in ATM-mediated phosphorylation and activation of the YAP1 transcriptional coactivator, which in turn up-regulates pro-IL-18, a pivotal immune regulator in IBD pathogenesis. Moreover, individuals with germline defects in telomere maintenance genes experience increased occurrence of intestinal inflammation and show activation of the ATM/YAP1/pro-IL-18 pathway in the intestinal epithelium. Here, we sought to determine the relevance of the ATM/YAP1/pro-IL-18 pathway as a potential driver of IBD, particularly older-onset IBD. Analysis of intestinal biopsy specimens and organoids from older-onset IBD patients documented the presence of telomere dysfunction and activation of the ATM/YAP1/precursor of interleukin 18 (pro-IL-18) pathway in the intestinal epithelium. Employing intestinal organoids from healthy individuals, we demonstrated that experimental induction of telomere dysfunction activates this inflammatory pathway. In organoid models from ulcerative colitis and Crohn's disease patients, pharmacological interventions of telomerase reactivation, suppression of DNA damage signaling, or YAP1 inhibition reduced pro-IL-18 production. Together, these findings support a model wherein telomere dysfunction in the intestinal epithelium can initiate the inflammatory process in IBD, pointing to therapeutic interventions for this disease.

Lymphocytic Esophagitis Is Not Similar to Eosinophilic Esophagitis Except for Seasonal Variation.

OBJECTIVE: Unlike eosinophilic esophagitis (EoE), there is no consensus on the minimum number of intraepithelial lymphocytes (IEL) that is diagnostic of lymphocytic esophagitis (LyE). The aim of this study was to determine whether significant correlations exist between the numbers of intraepithelial lymphocytes (IEL) in esophageal biopsies and clinical and endoscopic manifestations usually associated with EoE. METHODS: H&E slides from esophageal biopsies from 330 patients were reviewed. The number of IEL and intraepithelial eosinophils (IEE) per mm2 was counted in the area with the highest concentration in each biopsy. The numbers were then correlated with clinical and endoscopic findings. RESULTS: As expected, a higher number of IEE was significantly associated with food impaction (p=0.001), dysphagia (p=0.021), esophageal stricture (p=0.017), rings (P<0.0001), and furrows (p<0.0001). By contrast, there was no significant association between increased IEL and any of the aforementioned clinical and endoscopic features in the original 330 patients or in a subset of 233 patients with no IEE. Interestingly, the number of both IEE and IEL varied significantly by the season when the biopsy was obtained, being lowest in the fall and highest in the spring (p=0002 for IEE and p<0.0001 for IEL). CONCLUSION: In esophageal biopsies, increased IEL has no significant correlation with food impaction or dysphagia or with esophageal stricture, rings, or furrows. There is significant variation in the number of IEL depending on the season when the biopsy is obtained, which has not been previously reported.

Distinct Murine Pancreatic Transcriptomic Signatures during Chronic Pancreatitis Recovery.

We have previously demonstrated that the pancreas can recover from chronic pancreatitis (CP) lesions in the cerulein-induced mouse model. To explore how pancreatic recovery is achieved at the molecular level, we used RNA-sequencing (seq) and profiled transcriptomes during CP transition to recovery. CP was induced by intraperitoneally injecting cerulein in C57BL/6 mice. Time-matched controls (CON) were given normal saline. Pancreata were harvested from mice 4 days after the final injections (designated as CP and CON) or 4 weeks after the final injections (designated as CP recovery (CPR) and control recovery (CONR)). Pancreatic RNAs were extracted for RNA-seq and quantitative (q) PCR validation. Using RNA-seq, we identified a total of 3,600 differentially expressed genes (DEGs) in CP versus CON and 166 DEGs in CPR versus CONR. There are 132 DEGs overlapped between CP and CPR and 34 DEGs unique to CPR. A number of selected pancreatic fibrosis-relevant DEGs were validated by qPCR. The top 20 gene sets enriched from DEGs shared between CP and CPR are relevant to extracellular matrix and cancer biology, whereas the top 10 gene sets enriched from DEGs specific to CPR are pertinent to DNA methylation and specific signaling pathways. In conclusion, we identified a distinct set of DEGs in association with extracellular matrix and cancer cell activities to contrast CP and CPR. Once during ongoing CP recovery, DEGs relevant to DNA methylation and specific signaling pathways were induced to express. The DEGs shared between CP and CPR and the DEGs specific to CPR may serve as the unique transcriptomic signatures and biomarkers for determining CP recovery and monitoring potential therapeutic responses at the molecular level to reflect pancreatic histological resolution.

Kras mutation rate precisely orchestrates ductal derived pancreatic intraepithelial neoplasia and pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer-related death in the United States. Despite the high prevalence of Kras mutations in pancreatic cancer patients, murine models expressing the oncogenic mutant Kras (Krasmut) in mature pancreatic cells develop PDAC at a low frequency. Independent of cell of origin, a second genetic hit (loss of tumor suppressor TP53 or PTEN) is important for development of PDAC in mice. We hypothesized ectopic expression and elevated levels of oncogenic mutant Kras would promote PanIN arising in pancreatic ducts. To test our hypothesis, the significance of elevating levels of K-Ras and Ras activity has been explored by expression of a CAG driven LGSL-KrasG12V allele (cKras) in pancreatic ducts, which promotes ectopic Kras expression. We predicted expression of cKras in pancreatic ducts would generate neoplasia and PDAC. To test our hypothesis, we employed tamoxifen dependent CreERT2 mediated recombination. Hnf1b:CreERT2;KrasG12V (cKrasHnf1b/+) mice received 1 (Low), 5 (Mod) or 10 (High) mg per 20 g body weight to recombine cKras in low (cKrasLow), moderate (cKrasMod), and high (cKrasHigh) percentages of pancreatic ducts. Our histologic analysis revealed poorly differentiated aggressive tumors in cKrasHigh mice. cKrasMod mice had grades of Pancreatic Intraepithelial Neoplasia (PanIN), recapitulating early and advanced PanIN observed in human PDAC. Proteomics analysis revealed significant differences in PTEN/AKT and MAPK pathways between wild type, cKrasLow, cKrasMod, and cKrasHigh mice. In conclusion, in this study, we provide evidence that ectopic expression of oncogenic mutant K-Ras in pancreatic ducts generates early and late PanIN as well as PDAC. This Ras rheostat model provides evidence that AKT signaling is an important early driver of invasive ductal derived PDAC.

Aquaporin-5 Expression Is Reduced in Lymphocytic Colitis.

OBJECTIVE: Aquaporin-5 (AQP5) is a member of a family of water channel proteins involved in the bidirectional transfer of water across cell membranes. Lymphocytic colitis (LC) and collagenous colitis (CC) are clinically similar diseases characterized by chronic watery diarrhea in patients with usually unremarkable colonic mucosa on colonoscopy. The aim of this study was to determine whether AQP5 expression in colonic epithelium is altered in LC and CC. METHODS: Sections of formalin-fixed and paraffin-embedded colorectal biopsies from three control patients (CTL), 8 patients with chronic non-bloody diarrhea with biopsies negative for active inflammation or significant distortion (CTL-D), 8 patients with LC, and 5 with CC were stained for AQP5 using immunohistochemistry. The staining intensity was scored as 3 (strong), 2 (intermediate), 1 (weak), or 0 (no staining). Statistical analysis was performed using Prism 7 Statistical Soft-ware. RESULTS: AQP5 was strongly expressed (score 3) in the epithelial cells in all three CTL cases and all 8 CTL-D cases. In the 5 cases of CC, 3(60%) had score 3 and 2(40%) had score 2, but none had a score of 1 or 0. Of the 8 LC cases, 2(25%) had score 3, 3 had score 2(37.5%), and 3 had score 1(37.5%) (p=0.0031). In the three cases of LC with markedly reduced AQP5 (score 1), enteric steroid treatment did not lead to significant improvement in diarrhea. CONCLUSIONS: Colorectal AQP5 expression is reduced in most cases of LC. Markedly reduced AQP5 expression in LC may identify a subset of patients with suboptimal response to enteric steroid treatment. Additional larger studies are needed to confirm these findings.This abstract was presented in part at Digestive Diseases Week in San Diego, CA, May 2019.

Intestinal Spirochetosis: Case Series and Review of the Literature.

OBJECTIVE: This study aims to present the clinical, endoscopic, and histopathologic characteristics associated with intestinal spirochetosis (IS). It also serves to heighten awareness among pathologists, since the histologic appearance of spirochetosis could be subtle and easily overlooked. METHODS: Hematoxylin & eosin (H&E) slides and special stains of intestinal biopsies from six patients with a diagnosis of IS at our institution were reviewed. Clinical history, endoscopic, and histopathologic findings were obtained from electronic medical records. RESULTS: The patients presented with diverse clinical symptoms, and only one patient was asymptomatic. The most consistent symptoms were watery diarrhea and abdominal cramps. Two out of five treated patients reported symptomatic improvement after antibiotics therapy. The colonoscopy findings were not specific, ranging from normal mucosa to polyps, to mucosal ulcerations in one patient. On histologic examination, the typical "brush-like" organisms lying perpendicular to the surface epithelium are seen both on H&E stain and special stains. CONCLUSIONS: IS is usually an incidental histologic finding, and the association with symptoms is still unclear. The clinical presentation could be very diverse, hence, a long list of differential diagnosis should be ruled out. Additional clinical testing should be pursued if patients are unresponsive to antibiotic treatment.

Anti-TNF-α Biologics Do Not Reverse CDX2 Downregulation in Patients with Crohn's Disease.

OBJECTIVE: The caudal-related homeobox transcription factor 2 (CDX2) plays an important role in intestinal epithelial differentiation, proliferation, migration, and adhesion. It has been previously reported that TNF-α reduces CDX2 expression in cultured colon epithelial cells in a dose-dependent manner, and that this effect was reduced by adding the anti-TNF-α drug infliximab to the culture medium. The aim of this study was to determine whether CDX2 expression is reduced in biopsies from patients with Crohn's disease (CD), and whether treatment with anti-TNF-α drugs reverses CDX2 downregulation in these patients. METHODS: Sections of ileocolonic biopsy tissues from patients with CD, CD treated with anti-TNF-α biologics (CD-T), and controls were stained for CDX2 and evaluated using OTMIAS digital image analysis. RESULTS: CDX2 expression in biopsies from patients with CD and CD-T was lower than in controls (p=0.0003). CDX2 expression in CD-T did not increase (p=0.3292) and remained significantly lower than controls (p=0.0002). CONCLUSIONS: Although CDX2 is downregulated in CD, it did not revert to normal in patients treated with anti-TNF-α biologics.

Mst1/2 kinases restrain transformation in a novel transgenic model of Ras driven non-small cell lung cancer.

Non-small cell lung cancer remains a highly lethal malignancy. Using the tamoxifen inducible Hnf1b:CreERT2 (H) transgenic mouse crossed to the LsL-KrasG12D (K) transgenic mouse, we recently discovered that an Hnf1b positive cell type in the lung is sensitive to adenoma formation when expressing a mutant KrasG12D allele. In these mice, we observe adenoma formation over a time frame of three to six months. To study specificity of the inducible Hnf1b:CreERT2 in the lung, we employed lineage tracing using an mTmG (G) reporter allele. This technique revealed recombined, GFP+ cells were predominantly SPC+. We further employed this technique in HKG mice to determine Hnf1b+ cells give rise to adenomas that express SPC and TTF1. Review of murine lung tissue confirmed a diagnosis of adenoma and early adenocarcinoma, a pathologic subtype of non-small cell lung cancer. Our expanded mouse model revealed loss of Mst1/2 promotes aggressive lung adenocarcinoma and large-scale proteomic analysis revealed upregulation of PKM2 in the lungs of mice with genetic deletion of Mst1/2. PKM2 is a known metabolic regulator in proliferating cells and cancer. Using a human lung adenocarcinoma cell line, we show pharmacologic inhibition of Mst1/2 increases the abundance of PKM2, indicating genetic loss or pharmacologic inhibition of Mst1/2 directly modulates the abundance of PKM2. In conclusion, here we report a novel model of non-small cell lung cancer driven by a mutation in Kras and deletion of Mst1/2 kinases. Tumor development is restricted to a subset of alveolar type II cells expressing Hnf1b. Our data show loss of Mst1/2 regulates levels of a potent metabolic regulator, PKM2.