Quality metrics of screening colonoscopies performed by PAs.

BACKGROUND: Many communities face a shortage of qualified endoscopists. Training physician assistants (PAs) to perform colonoscopies can expand the availability of colorectal cancer screening. This study examined screening colonoscopy metrics and quality indicators among gastroenterologists, supervised PAs, and gastroenterology fellows. METHODS: Consecutive patients undergoing average-risk screening colonoscopy were stratified into one of three groups by endoscopist type. Procedure and pathology reports were reviewed for the technical performance and quality metrics of the providers. RESULTS: PAs performed comparably to gastroenterologists in technical performance and quality metrics, and demonstrated higher cecal intubation rates than their gastroenterologist colleagues. Comparisons of attending physicians and PAs grouped by years of experience also did not show notable differences in performance. CONCLUSIONS: In a supervised practice, PAs performed on par with their gastroenterology colleagues on established colonoscopy quality indicators. Following proper training, PAs can be employed in the provision of screening colonoscopy.

Insulinoma-associated protein 1 expression in primary and metastatic neuroendocrine neoplasms of the gastrointestinal and pancreaticobiliary tracts.

AIMS: Insulinoma-associated protein 1 (INSM1) is a transcription factor that is expressed in developing and mature neuroendocrine tissue. Recent studies have shown that INSM1 is a sensitive marker for neuroendocrine tumours. The aims of this study were to evaluate INSM1 expression in primary gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) and in their known metastases, in order to assess its sensitivity as compared with chromogranin-A (CgA) and synaptophysin (SYN), and to evaluate any change in expression between primary and metastatic disease. METHODS AND RESULTS: We identified 30 patients with primary GEP-NEN. Liver metastatic tissue was available for 26 patients; two patients had two metachronous metastatic foci, yielding a total of 28 metastatic cases. An additional two and seven non-paired cases of primary and metastatic grade 3 GEP-NEN, respectively, were included. To assess specificity, we evaluated the expression of these markers in other primary tumours (colorectal adenocarcinoma, acinar cell carcinoma, solid pseudopapillary neoplasm, cholangiocarcinoma, and hepatocellular carcinoma) and metastatic tumours in the liver (adrenal cortical, breast and prostate carcinomas) that may present as differential diagnoses. In our cohort, all of the primary GEP-NENs and 94% of the metastatic GEP-NENs expressed INSM1. INSM1 showed similar sensitivity to SYN and higher sensitivity than CgA in both primary and metastatic neoplasms. INSM1 has comparable specificity to CgA, and higher specificity than SYN. CONCLUSIONS: The nuclear reactivity and the high sensitivity and specificity of INSM1 make it a preferred neuroendocrine marker. In conclusion, INSM1 can be used as a single first-line marker for primary and metastatic GEP-NEN.

Reg4-induced mitogenesis involves Akt-GSK3ß-ß-Catenin-TCF-4 signaling in human colorectal cancer.

Upregulation of regenerating gene 4 (Reg4) is observed in many human gastrointestinal malignancies including colorectal cancer (CRC). We previously reported a Reg4-mediated induction of epidermal growth factor receptor-Akt-AP1 signaling regulating CRC cell apoptosis. However, the role of Reg4 in the regulation of CRC cell division is poorly understood. This study tests the hypothesis that Reg4 induces Akt-GSK3ß-ß-Catenin-TCF-4 signaling to regulate CRC cell division. In vitro models of human CRC were used to determine the role of Reg4 in regulation of CRC cell division. Cell cycle studies demonstrated that Reg4 treatment significantly decreased CRC cell number in G1 phase and increased in G2 phase. Subsequently Reg4 significantly increased the mitotic index of CRC cells. As assessed by real-time RT-PCR and Western blot analyses, Reg4 significantly increased the expression of cell cycle regulatory genes Cyclin D1 and D3, and associated Cyclin-dependent kinases (CDK4 and CDK6). Reg4-mediated increase in these genes involved a pathway that included an induced Akt activity by increasing phosphorylation of Thr308 and Ser473, a reduced glycogen synthase kinase 3ß (GSK-3ß) activity by increasing phosphorylation of Ser9, an induced nuclear translocation of ß-Catenin by decreasing phosphorylation of Ser33/37/Thr41, and an increased TCF-4 transcriptional activity. Furthermore, antagonism of Reg4-signaling using Reg4-specific mAbs (2H6 and 3E5) and Akt inhibitor significantly decreased, whereas agonism using GSK-3ß antagonist (SB216763) significantly increased mitotic index and proliferation of CRC cells. These results identify Reg4 as a key regulator of the CRC cell division and proliferation, hence a potential target of human CRC treatment.

Reg4 Interacts with CD44 to Regulate Proliferation and Stemness of Colorectal and Pancreatic Cancer Cells.

Regenerating Gene 4 (Reg4) is highly upregulated in gastrointestinal (GI) malignancies including colorectal and pancreatic cancers. Numerous studies demonstrated an association between higher Reg4 expression and tumor aggressiveness, intrinsic resistance to apoptotic death, and poor outcomes from GI malignancies. However, the precise receptor and underlying signaling mechanism have remained unknown. Although we previously reported a Reg4-mediated induction of EGFR activity in colorectal cancer cells, a direct interaction between Reg4 and EGFR was not observed. This study is focused on identifying the cell surface binding partner of Reg4 and dissecting its role in colorectal cancer and pancreatic cancer growth and stem cell survival. In vitro models of human colorectal cancer and pancreatic cancer were used to evaluate the results. Results of this study find: (i) Reg4 interacts with CD44, a transmembrane protein expressed by a population of colorectal cancer and pancreatic cancer cells; (ii) Reg4 activates regulated intramembrane proteolysis of CD44 resulting in γ-secretase-mediated cleavage and release of the CD44 intracytoplasmic domain (CD44ICD) that functions as a transcriptional activator of D-type cyclins involved in the regulation of cancer cell proliferation and Klf4 and Sox2 expression involved in regulating pluripotency of cancer stem cells; and (iii) Reg4 significantly increases colorectal cancer and pancreatic cancer cell proliferation and their clonogenic potential in stem cell assays. IMPLICATIONS: These results suggest that pro-proliferative and pro-stemness effects of Reg4 are mediated through γ-secretase-mediated CD44/CD44ICD signaling, hence strategies to disrupt Reg4-CD44-γ-secretase-CD44ICD signaling axis may increase cancer cell susceptibility to chemo- and radiotherapeutics.

Reg IV regulates normal intestinal and colorectal cancer cell susceptibility to radiation-induced apoptosis.

BACKGROUND & AIMS: Regenerating (Reg) gene IV is predominantly expressed in gastrointestinal cells and highly up-regulated in many gastrointestinal malignancies, including colorectal cancer (CRC). Human CRC cells expressing higher levels of Reg IV gene and its protein product (Reg IV) are resistant to conventional therapies, including irradiation (IR). However, the underlying mechanism is not well defined. METHODS: A murine model of IR-induced intestinal injury and in vitro and in vivo models of human CRC were used to determine the role of Reg IV in regulation of normal intestinal and colorectal cancer cell susceptibility to IR-induced apoptosis. RESULTS: Treatments of recombinant human Reg IV (rhR4) protein protected normal intestinal crypt cells from IR-induced apoptosis by increasing the expression of antiapoptotic genes Bcl-2, Bcl-XL, and survivin. However, overexpression of Reg IV in human CRC cells was associated with increased resistance to IR-induced apoptosis. Therefore, we used antagonism of Reg IV as a tool to increase CRC cell susceptibility to IR-induced cell death. Two complementary approaches using specific monoclonal antibodies and small interfering RNAs were tested in both in vitro and in vivo models of human CRC. Both approaches resulted in increased apoptosis and decreased cell proliferation, leading to decreased tumor growth and increased animal survival. Furthermore, these approaches increased CRC cell susceptibility to IR-induced apoptosis. CONCLUSIONS: These results implicate Reg IV as an important modulator of gastrointestinal cell susceptibility to IR; hence, it is a potential target for adjunctive treatments for human CRC and other gastrointestinal malignancies.

Dendritic cells produce CXCL13 and participate in the development of murine small intestine lymphoid tissues.

In the adult intestine, luminal microbiota induce cryptopatches to transform into isolated lymphoid follicles (ILFs), which subsequently act as sites for the generation of IgA responses. The events leading to this conversion are incompletely understood. Dendritic cells (DCs) are components of cryptopatches (CPs) and ILFs and were therefore evaluated in this process. We observed that the adult murine intestine contains clusters of DCs restricted to the CP/ILF continuum. A numerical and cell associative hierarchy in the adult intestine and a chronologic hierarchy in the neonatal intestine demonstrated that these clusters form after the coalescence of CD90+ cells to form CPs and before the influx of B220+ B lymphocytes to form ILFs. Cluster formation was dependent on lymphotoxin and the lymphotoxin beta receptor and independent of lymphocytes. The ILF DC population was distinguished from that of the lamina propria by the absence of CD4+CD11c+ cells and an increased proportion of CD11c+B220+ cells. The formation of clusters was not limited by DC numbers but was induced by luminal microbiota. Moreover, in the absence of the chemokine CXCL13, CP transformation into ILF was arrested. Furthermore, ILF DCs express CXCL13, and depletion of DCs resulted in regression of ILFs and disorganization of CPs. These results reveal DC participation in ILF transformation and maintenance and suggest that in part this may be due to CXCL13 production by these cells.

Reg4 and its downstream transcriptional activator CD44ICD in stage II and III colorectal cancer.

Reg4 is highly expressed in gastrointestinal malignancies and acts as a mitogenic and pro-invasive factor. Our recent works suggest that Reg4 binds with CD44 and induces its proteolytic cleavage to release intra-cytoplasmic domain of CD44 (CD44ICD). The goal of this study is to demonstrate clinical significance of the Reg4-CD44/CD44ICD pathway in stage II/III colon cancer and its association with clinical parameters of aggression. We constructed a tissue microarray (TMA) of 93 stage II/III matched colon adenocarcinoma patients, 23 with recurrent disease. The TMA was immunohistochemically stained for Reg4, CD44, and CD44ICD proteins and analyzed to identify associations with tumor characteristics, recurrence and overall survival. The TMA data analysis showed a significant correlation between Reg4 and CD44 (r2 = 0.23, P = 0.028), CD44 and CD44ICD (r2 = 0.36, p = 0.0004), and Reg4 and CD44ICD (r2 = 0.45, p ≤ 0.0001). Reg4 expression was associated with larger tumor size (r2 = 0.23, p = 0.026). Although, no association was observed between Reg4, CD44, or CD44ICD expression and disease recurrence, Reg4-positive patients had a median survival of 4 years vs. 7 years for Reg4-negative patients (p = 0.04) in patients who recurred. Inhibition of the Reg4-CD44/CD44ICD pathway may be a future therapeutic target for colon cancer patients.

Clostridium difficile-associated disease in allogeneic hematopoietic stem-cell transplant recipients: risk associations, protective associations, and outcomes.

The purpose of this study was to evaluate risk factors, protective factors, and outcomes associated with Clostridium difficile-associated disease (CDAD) in allogeneic hematopoietic stem-cell transplant (HSCT) recipients. A case-control study was performed with 37 CDAD cases and 67 controls. In the multivariable logistic regression analysis, receipt of a third or fourth generation cephalosporin was associated with increased risk of CDAD (OR = 4.6, 95% CI 1.6-13.1). Receipt of growth factors was associated with decreased risk of CDAD (OR=0.1, 95% CI 0.02-0.3). Cases were more likely to develop a blood stream infection after CDAD than were controls at any point before discharge (p < 0.001). CDAD cases were more likely than controls to develop new onset graft-vs.-host disease (GVHD) (p < 0.001), new onset severe GVHD (p < 0.001), or new onset gut GVHD (p = 0.007) after CDAD/discharge. Severe CDAD was a risk factor for death at 180 d in multivariable Cox proportional hazards regression (HR=2.6, 95% CI 1.1-6.2). CDAD is a significant cause of morbidity and mortality in allogeneic HSCT patients, but modifiable risk factors exist. Further study is needed to determine the best methods of decreasing patients' risk of CDAD.

Knockdown of RNA binding protein musashi-1 leads to tumor regression in vivo.

BACKGROUND & AIMS: In the gut, tumorigenesis is thought to arise from the stem cell population located near the base of intestinal and colonic crypts. The RNA binding protein musashi-1 (Msi-1) is a putative intestinal and progenitor/stem cell marker. Msi-1 expression is increased during rat brain development and in APC(min/+) mice tumors. This study examined a potential role of Msi-1 in tumorigenesis. METHODS: Msi-1 small interfering RNA (siRNA) was administered as a liposomal preparation to HCT116 colon adenocarcinoma xenografts in athymic nude mice and tumor volume was measured. Cell proliferation was assessed by hexosaminidase and 3-(4,5-dimethylthiazol 2-yl)-2,5-diphenyltetrazolium bromide MTT assays. siRNA-transfected cells were subjected to 12 Gy gamma-irradiation. Apoptosis was assessed by immunoreactive activated caspase-3 and mitosis was assessed by phosphorylated histone H3 staining. The tumor xenografts were stained similarly for phosphorylated histone H3, activated caspase-3, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling, Notch-1, and p21(WAF1). Furthermore, siRNA-transfected cells were subjected to cell-cycle analysis and Western blot analyses for Notch-1 and p21(WAF1). RESULTS: Knockdown of Msi-1 resulted in tumor growth arrest in xenografts, reduced cancer cell proliferation, and increased apoptosis alone and in combination with radiation injury. siRNA-mediated reduction of Msi-1 lead to mitotic catastrophe in tumor cells. Moreover, there was inhibition of Notch-1 and up-regulation of p21(WAF1) after knockdown of Msi-1. CONCLUSIONS: Our results show the involvement of Msi-1 in cancer cell proliferation, inhibition of apoptosis, and mitotic catastrophe, suggesting an important potential mechanism for its role in tumorigenesis.

Gastrin-mediated interleukin-8 and cyclooxygenase-2 gene expression: differential transcriptional and posttranscriptional mechanisms.

BACKGROUND & AIMS: Gastrin induces the expression of cyclooxygenase (COX)-2 and interleukin (IL)-8; however, the mechanism(s), especially in gastric epithelial cells, is not well understood. Here, we have determined the intracellular mechanisms mediating gastrin-dependent gene expression. METHODS: AGS-E human gastric cancer cell line stably expressing cholecystokinin-2 receptor was treated with amidated gastrin-17. Real-time polymerase chain reaction, Western blot, and enzyme-linked immunosorbent assay were performed to determine COX-2 and IL-8 expression and Akt, Erk, and p38 phosphorylation. Gene promoter activity was determined by luciferase assay. Electrophoretic mobility shift assay analysis was performed for nuclear factor kappaB (NF-kappaB) and activator protein-1 activity. RNA stability was determined after actinomycin D treatment. HuR localization was determined by immunocytochemistry. RESULTS: Gastrin induced COX-2 and IL-8 expression in AGS-E cells, which was inhibited by phosphatidylinositol 3' kinase (PI3K) and p38 inhibitors. Gastrin-mediated Akt activation was observed to be downstream of p38. IL-8 expression was dependent on COX-2-mediated prostaglandin E(2) synthesis. In the presence of an NF-kappaB inhibitor MG132, IL-8 transcription was inhibited, but not that of COX-2. This was confirmed after knockdown of the p65 RelA subunit of NF-kappaB. Further studies showed that COX-2 gene transcription is regulated by activator protein-1. Gastrin increased the stability of both COX-2 and IL-8 messenger RNA (mRNA) in a p38-dependent manner, the half-life increasing from 31 minutes to 8 hours and approximately 4 hours, respectively. Gastrin, through p38 activity, also enhanced HuR expression, nucleocytoplasmic translocation, and enhanced COX-2 mRNA binding. CONCLUSIONS: Gastrin differentially induces COX-2 and IL-8 expression at the transcriptional and posttranscriptional levels by PI3K and p38 mitogen-activated protein kinase pathways, respectively.

IDO1 and Kynurenine Pathway Metabolites Activate PI3K-Akt Signaling in the Neoplastic Colon Epithelium to Promote Cancer Cell Proliferation and Inhibit Apoptosis.

The tryptophan-metabolizing enzyme indoleamine 2,3 dioxygenase 1 (IDO1) is frequently overexpressed in epithelial-derived malignancies, where it plays a recognized role in promoting tumor immune tolerance. We previously demonstrated that the IDO1-kynurenine pathway (KP) also directly supports colorectal cancer growth by promoting activation of ß-catenin and driving neoplastic growth in mice lacking intact adaptive immunity. In this study, we sought to delineate the specific role of epithelial IDO1 in colon tumorigenesis and define how IDO1 and KP metabolites interact with pivotal neoplastic signaling pathways of the colon epithelium. We generated a novel intestinal epithelial-specific IDO1 knockout mouse and utilized established colorectal cancer cell lines containing ß-catenin-stabilizing mutations, human colorectal cancer samples, and human-derived epithelial organoids (colonoids and tumoroids). Mice with intestinal epithelial-specific knockout of IDO1 developed fewer and smaller tumors than wild-type littermates in a model of inflammation-driven colon tumorigenesis. Moreover, their tumors exhibited reduced nuclear ß-catenin and neoplastic proliferation but increased apoptosis. Mechanistically, KP metabolites (except kynurenic acid) rapidly activated PI3K-Akt signaling in the neoplastic epithelium to promote nuclear translocation of ß-catenin, cellular proliferation, and resistance to apoptosis. Together, these data define a novel cell-autonomous function and mechanism by which IDO1 activity promotes colorectal cancer progression. These findings may have implications for the rational design of new clinical trials that exploit a synergy of IDO1 inhibitors with conventional cancer therapies for which Akt activation provides resistance such as radiation.Significance: This study identifies a new mechanistic link between IDO1 activity and PI3K/AKT signaling, both of which are important pathways involved in cancer growth and resistance to cancer therapy.

REG1A expression is a prognostic marker in colorectal cancer and associated with peritoneal carcinomatosis.

By expression profiling of early staged colon carcinomas, we found regenerating islet-derived 1 alpha (REG1A) to be upregulated in patients with an unfavorable clinical outcome. For validation, REG1A expression was quantified in another colorectal cancer (CRC) patient cohort by Taqman PCR. Aside from tumor and normal tissue from 63 nonpretreated CRC patients, 31 mucosa biopsies from healthy individuals as well as 22 adenomas were included in the investigation. REG1A was significantly upregulated in tumor specimens (p < 0.001) and adenoma (p < 0.01) as compared to normal colorectal tissue. REG1A expression in normal peritumoral tissue in turn proved to be significantly elevated compared to mucosa from healthy individuals (p < 0.01). Determination of REG1A expression might be useful for early tumor diagnosis with a sensitivity of 90.6%, and a specificity of 77.9%. REG1A expression was significantly increased in tumors with peritoneal carcinomatosis (p < 0.01). Moreover, REG1A turned out to be a significant predictor of disease-free survival (p < 0.05). In conclusion, we present evidence that REG1A is a molecular marker of prognostic value and is associated with peritoneal carcinomatosis in CRC. REG1A turned out to be already significantly raised in peritumoral normal tissue compared to mucosa from healthy individuals, suggesting a molecular field effect of secreted REG1A.

Sargramostim for active Crohn's disease.

BACKGROUND: Sargramostim, granulocyte-macrophage colony-stimulating factor, a hematopoietic growth factor, stimulates cells of the intestinal innate immune system. Preliminary studies suggest sargramostim may have activity in Crohn's disease. To evaluate this novel therapeutic approach, we conducted a randomized, placebo-controlled trial. METHODS: Using a 2:1 ratio, we randomly assigned 124 patients with moderate-to-severe active Crohn's disease to receive 6 mug of sargramostim per kilogram per day or placebo subcutaneously for 56 days. Antibiotics and aminosalicylates were allowed; immunosuppressants and glucocorticoids were prohibited. The primary end point was a clinical response, defined by a decrease from baseline of at least 70 points in the Crohn's Disease Activity Index (CDAI) at the end of treatment (day 57). Other end points included changes in disease severity and the health-related quality of life and adverse events. RESULTS: There was no significant difference in the rate of the primary end point of a clinical response defined by a decrease of at least 70 points in the CDAI score on day 57 between the sargramostim and placebo groups (54 percent vs. 44 percent, P=0.28). However, significantly more patients in the sargramostim group than in the placebo group reached the secondary end points of a clinical response defined by a decrease from baseline of at least 100 points in the CDAI score on day 57 (48 percent vs. 26 percent, P=0.01) and of remission, defined by a CDAI score of 150 points or less on day 57 (40 percent vs. 19 percent, P=0.01). The rates of either type of clinical response and of remission were significantly higher in the sargramostim group than in the placebo group on day 29 of treatment and 30 days after treatment. The sargramostim group also had significant improvements in the quality of life. Mild-to-moderate injection-site reactions and bone pain were more common in the sargramostim group, and three patients in this group had serious adverse events possibly or probably related to treatment. CONCLUSIONS: This study was negative for the primary end point, but findings for the secondary end points suggest that sargramostim therapy decreased disease severity and improved the quality of life in patients with active Crohn's disease.

Granulocyte macrophage colony-stimulating factor ameliorates DSS-induced experimental colitis.

BACKGROUND: Sargramostim, granulocyte macrophage colony-stimulating factor (GM-CSF), a hematopoietic growth factor, stimulates cells of the intestinal innate immune system. Clinical trials show that sargramostim induces clinical response and remission in patients with active Crohn's disease. To study the mechanism, we examined the effects of GM-CSF in the dextran sulfate sodium (DSS)-induced acute colitis model. We hypothesized that GM-CSF may work through effects on dendritic cells (DCs). METHODS: Acute colitis was induced in Balb/c mice by administration of DSS in drinking water. Mice were treated with daily GM-CSF or phosphate-buffered saline (PBS). To probe the role of plasmacytoid DCs (pDCs) in the response to GM-CSF, we further examined the effects of monoclonal antibody 440c, which is specific for a sialic acid-binding immunoglobulin (Ig)-like lectin expressed on pDCs. RESULTS: GM-CSF ameliorates acute DSS-induced colitis, resulting in significantly improved clinical parameters and histology. Microarray analysis showed reduced expression of proinflammatory genes including TNF-alpha and IL1-beta; the results were further confirmed by real-time reverse-transcriptase polymerase chain reaction and serum Bio-plex analysis. GM-CSF treatment significantly expands pDCs and type 1 IFN production. Administration of mAb 440c completely blocked the therapeutic effect of GM-CSF. GM-CSF is also effective in RAG1(-/-) mice, demonstrating activity-independent effects on T and B cells. IFN-beta administration mimics the therapeutic effect of GM-CSF in DSS-treated mice. GM-CSF increases systemic and mucosal type 1 IFN expression and exhibits synergy with pDC activators, such as microbial cytosine-phosphate-guanosine (CpG) DNA. CONCLUSIONS: GM-CSF is effective in the treatment of DSS colitis in a mechanism involving the 440c(+) pDC population.

A Randomized Trial of Off-Site Collaborative Care for Depression in Chronic Hepatitis C Virus.

OBJECTIVE: To test the effectiveness of a collaborative depression care model in improving depression and hepatitis C virus (HCV) care. DATA SOURCES/STUDY SETTING: Hepatitis C virus clinic patients who screened positive for depression at four Veterans Affairs Hospitals. STUDY DESIGN: We compared off-site depression collaborative care (delivered by depression care manager, pharmacist, and psychiatrist) with usual care in a randomized trial. Primary depression outcomes were treatment response (≥50 percent decrease in 20-item Hopkins Symptoms Checklist [SCL-20] score), remission (mean SCL-20 score, <0.5), and depression-free days (DFDs). Primary HCV outcome was receipt of HCV treatment. DATA COLLECTION: Patient data were collected by self-report telephone surveys at baseline and 12 months, and from electronic medical records. PRINCIPAL FINDINGS: Baseline screening identified 292 HCV-infected patients with depression, and 242 patients completed 12-month follow-up (82.9 percent). Intervention participants were more likely to report depression treatment response, remission, and more DFDs than usual care participants. Intervention participants were more likely to receive antiviral treatment; however, the difference was not statistically significant. CONCLUSION: Off-site depression collaborative care improved depression outcomes in HCV patients and may serve as a model for collaboration between mental health and specialty physical health providers in other high co-occurring conditions.

Characterization of cecal gene expression in a differentially susceptible mouse model of bacterial-induced inflammatory bowel disease.

BACKGROUND: A/JCr mice develop typhlitis in response to Helicobacter hepaticus infection, whereas C57BL/6 mice coexist with this bacterium in a "commensal" relationship and do not develop disease even during prolonged colonization. METHODS: To determine mechanisms that control this balance between responsiveness and nonresponsiveness, the mucosal response of A/JCr and C57BL/6 mice to acute H. hepaticus colonization was evaluated using genome-wide profiling. Transcription levels for a subset of gene discoveries were then evaluated longitudinally by semiquantitative real-time reverse-transcriptase polymerase chain reaction (RT-PCR) to identify changes in gene expression that occur during progression from the acute to chronic phase of colonization. To determine whether chronic mucosal inflammation in A/JCr mice was mediated through a Th1 mechanism, as was inferred from the gene expression data, mice with typhlitis were treated with neutralizing antibody targeting IL-12/23p40 or IFN-gamma and the response to treatment was determined by cecal lesion severity and transcription of disease-related genes. RESULTS: A/JCr mice had a biphasic expression of proinflammatory genes that corresponded with the acute and chronic phases of disease. In contrast, C57BL/6 mice exhibited a less robust acute transcriptional response that waned by day 30 postinoculation. Sustained upregulation of proinflammatory signals and responsiveness to anti-IL-12/23p40 and anti-IFN-gamma antibody suggests that inflammation in A/JCr mice was mediated through a Th1 mechanism. Prolonged upregulation of SOCS3 during the acute response to colonization suggests that C57BL/6 mice maintain mucosal homeostasis, at least in part by attenuating responsiveness to cytokine signaling. CONCLUSIONS: Collectively, these findings provide a foundation for understanding the immunological mechanisms that confer resistance or susceptibility to H. hepaticus-induced typhlitis.

Dysregulation of Reg gene expression occurs early in gastrointestinal tumorigenesis and regulates anti-apoptotic genes.

Expression of anti-apoptotic genes is frequently elevated in tumors, where they increase resistance to chemotherapeutic agents and predict poor patient outcomes. However, key cellular factors regulating anti-apoptotic genes in tumors remain unknown. Increased expression of the regenerating (Reg) genes is commonly observed in gastrointestinal (GI) malignancies including colorectal cancer (CRC). We therefore examined Reg gene expression and associated changes in anti-apoptotic genes in an animal model of GI tumorigenesis. Using real time RT-PCR, we measured expression of Reg genes in human colorectal adenocarcinoma specimens, colon adenocarcinoma cell lines and adenomas from multiple intestinal neoplasia (min) mice heterozygous for a germ-line mutation of the adenomatous polyposis coli (APC) gene. Expression of Reg genes is increased in human colorectal adenocarcinomas and in the intestine of APCmin/+ mice at four weeks of age, a time preceding the spontaneous second mutation in the APC gene. Individual Reg genes exhibited regional expression profiles across the GI tract in mice. Adenomas from 14-week old mice had significant increases in at least one member of the Reg gene family, most commonly Reg IV and an associated increase in expression of the anti-apoptotic gene, Bcl-2. Addition of exogenous recombinant human Reg IV to human colon adenocarcinoma cells significantly increased Bcl-2 and Bcl-xL expression and induced resistance to ionizing radiation. These results show that dysregulation of Reg genes occur early in tumorigenesis. Furthermore, increased expression of Reg genes, specifically Reg IV contribute to adenoma formation and lead to increased resistance to apoptotic cell death in CRC.

Growth factors as treatment options for intestinal inflammation.

On the basis of several studies that have been completed to date, some growth factors appear promising for the treatment of inflammatory bowel disease: keratinocyte-like growth factor-2 (KGF-2), epidermal growth factor (EGF) enemas used in combination with oral mesalamine, somatropin (human growth hormone), and sargramostim (recombinant human GM-CSF). The results of these studies are highlighted and suggest that new insights into the regulation of intestinal immunity may provide effective synergistic or single-agent treatment alternatives to immunosuppression for inflammatory bowel disease. These data focus on the reparative components of mucosal homeostasis.

Pancreatic regenerating protein (reg I) and reg I receptor mRNA are upregulated in rat pancreas after induction of acute pancreatitis.

AIM: Pancreatic regenerating protein (reg I) stimulates pancreatic regeneration after pancreatectomy and is mitogenic to ductal and beta-cells. This suggests that reg I and its receptor may play a role in recovery after pancreatic injury. We hypothesized that reg I and its receptor are induced in acute pancreatitis. METHODS: Acute pancreatitis was induced in male Wistar rats by retrograde injection of 3% sodium taurocholate into the pancreatic duct. Pancreata and serum were collected 12, 24, and 36 h after injection and from normal controls (4 rats/group). Reg I receptor mRNA, serum reg I protein, and tissue reg I protein levels were determined by Northern analysis, enzyme-linked immunosorbent assay (ELISA), and Western analysis, respectively. Immunohistochemistry was used to localize changes in reg I and its receptor. RESULTS: Serum amylase levels and histology confirmed necrotizing pancreatitis in taurocholate treated rats. There was no statistically significant change in serum reg I concentrations from controls. However, Western blot demonstrated increased tissue levels of reg I at 24 and 36 h. This increase was localized primarily to the acinar cells and the ductal cells by immunohistochemistry. Northern blot demonstrated a significant increase in reg I receptor mRNA expression with pancreatitis. Immunohistochemistry localized this increase to the ductal cells, islets, and acinar cells. CONCLUSION: Acute pancreatitis results in increased tissue reg I protein levels localized to the acinar and ductal cells, and a parallel threefold induction of reg I receptor in the ductal cells, islets, and acinar cells. These changes suggest that induction of reg I and its receptor may be important for recovery from acute pancreatitis.