Showing papers by "Fergus Shanahan published in 2003"

Double blind, placebo controlled trial of two probiotic strains in interleukin 10 knockout mice and mechanistic link with cytokine balance

Abstract: Background: Prophylactic efficacy against colitis following lactobacillus consumption in interleukin 10 (IL-10) knockout (KO) mice has been reported. Whether this applies equally to other probiotic strains is unknown, and the mechanism is unclear. Aims: (1) To compare the effect of feeding Lactobacillus salivarius subspecies salivarius 433118 and Bifidobacterium infantis 35624 against placebo on enterocolitis, the intestinal microflora, and (2) to compare the systemic immunological response to in vitro microbial challenge in probiotic fed and control IL-10 KO mice. Methods: Three groups of 10 IL-10 KO mice were fed fermented milk products containing Lb salivarius 433118 at 10 9 CFU/ml, B infantis 35624 at 10 8 CFU/ml, and unmodified milk, respectively, for 19 weeks. Faecal samples were taken at regular intervals to confirm gut transit, recovery of fed probiotics, and to assess the impact on the microflora. At sacrifice, the bowels were histologically scored. Cytokine production from Peyers’ patches and splenocytes was measured in vitro by ELISA. Results: Faecal recovery of probiotics was confirmed in all probiotic fed mice but not in controls. Colonic and caecal inflammatory scores were significantly decreased in both groups of probiotic fed mice (p Conclusion: Both Lactobacillus salivarius 433118 and Bifidobacterium infantis 35624 significantly attenuate colitis in this murine model. Attenuation of colitis is associated with a reduced ability to produce Th1-type cytokines systemically and mucosally, while levels of TGF-β are maintained.

Inflammatory Bowel Disease: From Bench to Bedside

Abstract: Preface. Section 1: The Laboratory Bench. 1. Introduction: Inflammatory Bowel Diseases: From Bench to Bedside F. Shanahan, et al. 2. The Changing Faces of Crohn's Disease and Ulcerative Colitis A. Ekbom. 3. Genetics of Inflammatory Bowel Disease K.D. Taylor, J.I. Rotter, H. Yang. 4. Experimental Mouse Models of Inflammatory Bowel Disease: New Insights Into Pathogenic Mechanisms C.O. Elson, C. T. Weaver. 5. The Normal Intestinal Mucosa - A State of 'Controlled Inflammation' C. Fiochi. 6. The Lymphocyte-Epithelial-Bacterial Interface R. Hershberg, R. Blumberg. 7. The Mucosal Inflammatory Response. Cytokines and Chemokines F. Cominelli, K. O. Arseneau, T. T. Pizarro 8. Role of the Microcirculation in Chronic Gut Inflammation M. B. Grisham, F. S. Laroux, D. N. Granger. 9. Remission, Relapse, Intestinal Healing and Repair M. N. Goke, D. Podolsky. 10. Antibodies in the Exploration of Inflammatory Bowel Disease Pathogenesis and Disease Stratification J. Braun, O. Cohavy, M. Eggena. 11. Pathophysiology of Inflammatory Bowel Disease: The Effect of Inflammation on Intestinal Function S. M. Collins, K. Croitoru. 12. Systemic Consequences of Intestinal Inflammation K. A. Papadakis, M.T. Abreu. Section II: The Bedside. 13. Understanding Symptoms and Signs in Inflammatory Bowel Disease C. C. Cronin, F. Shanahan 14. Clinical Course and Complications of Ulcerative Colitis and Ulcerative Proctitis R. Panaccione, L. R. Sutherland. 15. Clinical Features and Complications of Crohn's Disease W. J. Tremaine. 16. Mechanisms of Systemic Inflammation Associated With Intestinal Injury R. B. Sartor. S. N. Lichtman 17. Pathology of Inflammatory Bowel Diseases: A Critical Appraisal in Diagnosis and Management G. Cortina, K. Lewin. 18. An Endoscopic and Histologic Perspective of Diagnosis: When, Where and What to Do C. N. Bernstein, R. H. Riddell. 19. Radiologic (Radiographic) and Imaging Features of Ulcerative Colitis and Crohn's Disease E. Fitzgerald. 20. New Diagnostic Approaches L. Kam, E. Vasiliauskas. 21. Differential Diagnosis of Colitis S. C. Eng, C. M. Surawicz. 22. 'Disease Management' in Chronic Medical Conditions D. H. Alpers. 23. Pharmacoeconomic and Inflammatory Bowel Disease B. G. Feagan. 24. Measuring Quality of Life in Inflammatory Bowel Disease E.J. Irvine. 25 Additional Chapters. Section III: Back to the Laboratory Bench. 50. Epilogue: Bench to Bedside and Back to Bench S.R. Targan, L. C. Karp, F. Shanahan. Index.

Basic aspects and pharmacology of probiotics: an overview of pharmacokinetics, mechanisms of action and side-effects.

Abstract: Probiotics have been defined as non-pathogenic micro-organisms that, when ingested, exert a positive influence on host health or physiology. Their pharmacology is more complex than that of inert drugs but is now being studied in detail. Some strains have a high survival capacity until they reach the faeces, whereas others are rapidly killed by acid and bile (a characteristic that can be used for the delivery of active intracellular components). Potential translocation and permanent colonization are rare but possible events; and should come under closer scrutiny. Mechanisms of action can be direct or indirect through modifications of the endogenous flora or through immunomodulation. The active components are poorly known but include bacterial formylated peptides, peptidoglycan cell wall constituents and nucleotides. Although the safety of commercial probiotics is excellent, this aspect should be studied in more detail, especially in immunocompromised hosts.

Acromegaly and colorectal cancer: a comprehensive review of epidemiology, biological mechanisms, and clinical implications.

Abstract: Acromegaly is an endocrine disorder characterised by sustained hypersecretion of growth hormone (GH) with concomitant elevation of insulin-like growth factor (IGF)-I, and is associated with malignancy and premature mortality from cardiovascular and respiratory diseases. In particular, there may be an increased risk of colorectal neoplasia, but the exact extent of this is contentious. Colonoscopy-based studies of adenoma prevalence rates in acromegalic patients are misleading, but population-based studies on colorectal cancer risk are more consistent - a meta-analysis estimated a pooled risk ratio of 2.04 (95 % CI: 1.32, 3.14). Possible mechanisms underlying this increased risk include direct actions as a consequence of elevated levels of circulating GH and IGF-I and/or other perturbations within the IGF system. Other possible mechanisms include altered bile acid secretion, altered cellular immunity, hyperinsulinaemia, shared genetic susceptibility and increased bowel length. However, most explanations only offer indirect evidence, and the expectation of acromegaly as a natural model of colorectal carcinogenesis has not materialised. From a clinical perspective, it seems reasonable to consider a once-only colonoscopic screening at approximately age 55 years, but potential risks and benefits should be balanced.

Is nutrition an aetiological factor for inflammatory bowel disease

Abstract: Inflammatory bowel disease (IBD) is a chronic inflammatory process, the aetiology of which is complex and probably multi-factorial. Nutrition has been proposed to be an important aetiological factor for IBD. The present review critically examines the relationship between components of the diet (such as sugar, fat, fibre, fruit and vegetables, and protein) and IBD, including ulcerative colitis and Crohn's disease. In addition, it investigates the possible role of infant feeding practices in the development of IBD.

Association of NOD2 with Crohn's Disease in a homogenous Irish population

Abstract: Linkage of IBD to the pericentromeric region of chromosome 16 has been widely confirmed by analyses of multiple populations. The NOD2 gene is located in the peak region of linkage on chromosome 16 and thought to be involved in the activation of nuclear factor (NF) kappaB in response to bacterial components. Mutations in the NOD2 gene are found to be strongly associated with susceptibility to Crohn's disease (CD). A total of 65 Irish CD families were genotyped to determine if NOD2 mutations conferred susceptibility to CD and the prevalence of these mutations in sporadic and familial forms of the disease. The Irish population is relatively homogenous and thus may provide advantages in genetic studies of complex diseases. We confirmed the IBD1 locus as a susceptibility locus for IBD within the Irish population by linkage analysis followed by linkage disequilibrium studies. No significant evidence of linkage was observed to the previously identified regions on chromosomes 1, 12 and 14. In all, 131 CD affected families were then genotyped for seven of the previously published NOD2 single-nucleotide polymorphisms (SNPs). Allelic transmission distortion was investigated using the pedigree disequilibrium test (PDT). SNP13 (3020insC) was found to be associated with CD (P=0.0186). Patients who possessed a rare allele of SNP8, 12 or 13 presented earlier when compared to patients without rare variants (mean age, 20.1 vs 24 years, P=0.011) and the rare allele of SNP13 was observed to be predominantly linked to ileal disease (P=0.02). This report confirms the importance of NOD2 as a susceptibility gene for CD within the Irish population.

Fas ligand mediates immune privilege and not inflammation in human colon cancer, irrespective of TGF-β expression

Abstract: Many cancers express Fas ligand (FasL/CD95L) in vivo, and can kill lymphoid cells by Fas-mediated apoptosis in vitro However, overexpression of recombinant FasL in murine tumour allografts revealed a potential antitumour effect of FasL, via recruitment of neutrophils Transforming growth factor-beta1 (TGF-beta1) could inhibit these neutrophil-stimulatory effects of FasL In the present study, we sought to determine directly whether FasL contributes to immune privilege or tumour rejection in human colon cancers in vivo, and whether TGF-beta1 regulates FasL function Serial tumour sections were immunostained for FasL and TGF-beta1 Neutrophils and tumour infiltrating lymphocytes (TILs) were detected by immunohistochemistry for lactoferrin and CD45, respectively Apoptotic TIL were identified by dual staining for TUNEL/CD45 FasL expression by nests of tumour cells was associated with a mean four-fold depletion of TILs (range 18-33-fold, n=16, P<0001), together with a two-fold increase in TIL apoptosis (range 16-25-fold, n=14, P<0001), relative to FasL-negative nests within the same tumours The overall level of neutrophils present in all tumours examined was low (mean 03%, n=16), with FasL expression by tumour nests associated with a mean two-fold decrease in neutrophils, irrespective of TGF-beta1 expression Together, our results suggest that tumour-expressed FasL is inhibitory rather than stimulatory towards antitumour immune responses

Manipulation of the bacterial flora in inflammatory bowel disease.

Abstract: In this chapter we summarize the clinical and experimental data which indicate that bacteria, especially from the endogenous microflora, play a role in the pathogenesis of Crohn's disease, ulcerative colitis and pouchitis. We review the clinical trials, focusing on randomized controlled trials which used antibiotics or probiotics to treat situations of IBD or prevent recurrence, and we discuss the future of this approach.

Neurokinin-1 receptor (NK-1R) expression is induced in human colonic epithelial cells by proinflammatory cytokines and mediates proliferation in response to substance P.

Abstract: We have previously shown that the receptor for substance P (SP), neurokinin-1 receptor (NK-1R), is a marker of human mucosal but not peripheral mononuclear cells. In the present study, we investigate NK-1R expression in the human colonic mucosa in vivo, particularly in the epithelial cells. We investigate the influence of proinflammatory Th1 cytokines and SP on expression and function of NK-1R in colonic epithelial cells in vitro. Using in situ hybridization to detect NK-1R mRNA, and immunohistochemistry to detect NK-1R protein, colonic epithelial cells were found to express NK-1R in vivo. In contrast, colon epithelial cell lines (Caco-2, HT29, SW620, T84) were negative for NK-1R mRNA and protein. However, stimulation with a proinflammatory cytokine cocktail containing IFN-gamma, TNF-alpha, and IL-1beta, caused induction of NK-1R expression. Expression of NK-1R in human colonic epithelial cells in vivo may therefore reflect cytokine conditioning by the mucosal microenvironment. SP did not alter ion transport in monolayers of cytokine-treated T84 cells. While SP stimulated epithelial ion transport in colonic mucosae ex vivo, this was not a direct effect of SP on the epithelial cells, and appeared to be neurally mediated. However, SP (10(-10)-10(-8) M) elicited a dose-dependent proliferative effect on cytokine-stimulated, but not unstimulated, SW620 cells. Proliferation of the epithelial cells in response to SP was mediated specifically via cytokine-induced NK-1R, since an NK-1R-specific antagonist (Spantide 1) completely blocked SP-mediated proliferation in the cytokine-treated cells. Our results therefore demonstrate that proinflammatory cytokines induce expression of NK-1R in human colonic epithelial cell lines, and that SP induces proliferation of the epithelial cells via cytokine-induced NK-1R.

Probiotics: a perspective on problems and pitfalls.

Abstract: Therapeutic manipulation of gut flora with probiotics promises to be a useful strategy for several disorders, including infectious, inflammatory and neoplastic conditions. However, there are large gaps in the knowledge of the normal flora and of the optimal use of probiotic products. At present, there is no reliable in vitro predictor of in vivo efficacy of putative probiotics. Indeed, probiotic performance should be defined in the context of the disease indication for which it is intended. This will require rigorous prospective clinical trials. In addition, guidelines for routine clinical use of probiotics are confounded by insufficient data on optimum strain selection, dose, delivery vehicle and monitoring. Before the promise can be fulfilled, problems and potential pitfalls with probiotic therapy need resolution.

Suggestive linkage of 2p22-25 and 11q12-13 with low bone mineral density at the lumbar spine in the Irish population

Abstract: Osteoporosis is a disease characterized by low bone mineral density (BMD) and poor bone quality. Peak bone density is achieved by the third decade of life, after which bone is maintained by a balanced cycle of bone resorption and synthesis. Age-related bone loss occurs as the bone resorption phase outweighs the bone synthesis phase of bone metabolism. Heritability accounts for up to 90% of the variability in BMD. Chromosomal loci including 1p36, 2p22-25, 11q12-13, parathyroid hormone receptor type 1 (PTHR1), interleukin-6 (IL-6), interleukin 1 alpha (IL-1alpha) and type II collagen A1/vitamin D receptor (COL11A1/VDR) have been linked or shown suggestive linkage with BMD in other populations. To determine whether these loci predispose to low BMD in the Irish population, we investigated 24 microsatellite markers at 7 chromosomal loci by linkage studies in 175 Irish families of probands with primary low BMD (T-score 1.0, D2S149, D11S1313, D11S987, D11S1314 including those encompassing the PTHR1 (D3S3559, D3S1289) for lumbar spine BMD and D2S149 for femoral neck BMD. Our data suggest that genes within a these chromosomal regions are contributing to a predisposition to low BMD in the Irish population.

Fas ligand expressed in colon cancer is not associated with increased apoptosis of tumor cells in vivo

Abstract: Expression of Fas ligand (FasL/CD95L) may help to maintain colon cancers in a state of immune privilege by inducing apoptosis of antitumor immune effector cells. Colon tumor-derived cell lines appear to be relatively insensitive to apoptosis mediated by their own or exogenous FasL in vitro, despite expression of cell surface Fas. In our present study, we sought to investigate if FasL upregulated in human colon cancers leads to any increase in apoptosis of the tumor cells in vivo. FasL and Fas receptor (APO-1/CD95) expression by tumor cells were detected immunohistochemically. Apoptotic tumor cell death was detected by immunohistochemistry for caspase-cleaved cytokeratin-18. FasL expression did not correlate with the extent of apoptosis of tumor cells. There was no significant local difference in the frequency of apoptosis of tumor cells between tumor nests that expressed FasL (mean = 2.4%) relative to those that did not (mean = 2.6%) (p = 0.625, n = 10; Wilcoxon signed rank). FasL expressed by the tumor cells appeared to be functional, since FasL expression in tumor nests correlated with diminished infiltration of tumor-infiltrating lymphocytes (TILs). TILs were detected using immunohistochemistry for CD45. Expression of FasL by tumor nests was associated with a mean 4-fold fewer TILs relative to FasL-negative nests (range 2.4–33-fold, n = 10, p < 0.003). Together, our results indicate that colon tumors are insensitive to FasL-mediated apoptosis in vivo. © 2003 Wiley-Liss, Inc.

Review article: colitis-associated cancer -- time for new strategies.

Abstract: Colorectal cancer (CRC) remains a feared and potentially life-threatening complication of both ulcerative colitis and Crohn's colitis. Currently, the main preventive strategy is a secondary one, i.e. surveillance colonoscopy usually after 8 years of disease duration, when the risk for neoplasia begins to increase. Despite its widespread acceptance, dysplasia and cancer surveillance is unproven in terms of reducing mortality or morbidity and there is a remarkable lack of uniformity in the manner in which it is practised. In this review article, the pitfalls of dysplasia surveillance are summarized and the need for novel chemopreventive and perhaps pharmabiotic approaches for prevention are highlighted.

The prophylactic use of a proton pump inhibitor before food and alcohol

Abstract: Summary Background : Patients report that the prophylactic consumption of a proton pump inhibitor minimizes gastrointestinal symptoms expected to be provoked by late-night food and alcohol consumption. The efficacy of this practice has not been studied formally. Aim : To perform a randomized, double-blind, placebo-controlled trial of a single dose of lansoprazole (30 mg) taken prior to a large meal and alcohol consumption. Methods : Study subjects were recruited randomly from local primary care and hospital physicians. Each participant (n = 56; 37 male, 19 female; mean age, 38 years) completed questionnaires before and after the meal. Approximately 90 min prior to the provocative meal, participants were witnessed taking either placebo or 30 mg lansoprazole. Bar tokens were dispensed to permit the accurate quantification of alcohol consumption (mean, 15 units). Results : Forty per cent of subjects reported significant reflux symptoms. For the entire group, there was no significant difference between lansoprazole and placebo. Post-prandial reflux was more frequent in those consuming > 15 units of alcohol (13/26, 50%) compared with those consuming 15 units of alcohol, lansoprazole was associated with a lower rate of heartburn (5/15, 33%) compared with placebo (8/11, 73%; P < 0.05). Conclusion : A single dose of a proton pump inhibitor prior to indulgence was only associated with reduced heartburn in those consuming > 15 units of alcohol.

Upregulation of neurokinin-1 receptor expression in the lungs of patients with sarcoidosis.

Abstract: Substance P (SP) is a proinflammatory neuropeptide that is secreted by sensory nerves and inflammatory cells Increased levels of SP are found in sarcoid bronchoalveolar lavage fluid SP acts by binding to the neurokinin-1 receptor and increases secretion of tumor necrosis factor-α in many cell types We sought to determine neurokinin-1 receptor expression in patients with sarcoidosis compared with normal controls Neurokinin-1 receptor messenger RNA and protein expression were below the limits of detection by reverse transcriptase-polymerase chain reaction and immunohistochemistry in peripheral blood mononuclear cells of healthy volunteers (n = 9) or patients with stage 1 or 2 pulmonary sarcoidosis (n = 10), but were detected in 1/9 bronchoalveolar lavage cells of controls compared with 8/10 patients with sarcoidosis (p = 0012) and 2/9 biopsies of controls compared with 9/10 patients with sarcoidosis (p = 0013) Immunohistochemistry localized upregulated neurokinin-1 receptor expression to bronchial and alveolar epithelial cells, macrophages, lymphocytes, and sarcoid granulomas The patient in whom neurokinin-1 receptor was not detected was taking corticosteroids Incubation of the type II alveolar and bronchial epithelial cell lines A549 and SK-LU 1 with dexamethasone downregulated neurokinin-1 receptor expression Upregulated neurokinin-1 receptor expression in patients with sarcoidosis may potentiate substance P-induced proinflammatory cytokine production in patients with sarcoidosis

Bifidobacteriumin the treatment of inflammatory disease

Abstract: A strain of Bifidobacterium isolated from resected and washed human gastrointestinal tract is significantly immunomodulatory following oral consumption in humans. The strain is useful in the prophylaxis and/or treatment of undesirable inflammatroy activity, especially gastrointestinal inflammatory activity such as inflammatory bowel disease or irritable bowel syndrome. The inflammatory activity may also be due to cancer.

Oral immune tolerance to tumor specific antigens may confer growth advantage to esophageal and gastric cancers

Abstract: SUMMARY Oral administration of antigens induces antigen-specific systemic immune tolerance (Oral Tolerance). We postulate that the poorer prognosis of foregut cancers might, in part be explained by the systemic immune tolerizing effect of tumor specific antigens shed into and processed by the gut immune system thus conferring a growth advantage specific to individual cancers. Immunocompetent Balb/c mice were fed by gavage, either tumor tissue (JBS/CarB) in phosphate buffered saline (PBS) or PBS alone, daily for 14 days. On day 15 either subcutaneous tumors were induced or animals were immunized with cells in adjuvant. JBS tumors appeared earlier and grew faster in the JBS tumor fed mice than in either the PBS (P = 0.025) or CarB (P = 0.168) fed animals. The delayed type hypersensitivity response in tolerized mice was significantly abrogated (P < 0.01) compared to controls. These experiments demonstrate antigen specific oral immune tolerance for tumors, which is reflected in a faster growth rate and impaired delayed type hypersensitivity response. Similar mechanisms may be operational in human esophagogastric malignancy and may in part explain their poorer outcome.

Role of antibiotics and probiotics in the management of inflammatory bowel disease

Abstract: An infectious cause or contribution to the primary pathogenesis of inflammatory bowel disease (IBD) has not been demonstrated, ahhough many studies have followed that track [1]. However, the deleterious role of some microorganisms from the endogenous flora is also now well estabhshed in the majority of models of colitis or enteritis [1-4]. Antibiotics have a weU-estabHshed role in the management of complications of IBD such as abscess and pouchitis. Whether antibiotics are of use as a primary therapy for either Crohn's disease (CD) or ulcerative colitis (UC) is less clear. An alternative way of influencing intestinal ecology is the use of probiotics or prebiotics. Probiotics are defined as living non-pathogenic microorganisms which, when ingested, exert a positive influence on host health or physiology [5, 6]. Prebiotics have been defined as non-digestible food ingredient that beneficially affects the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon, that have the potential to improve host health [7]. As some animal studies have shown that probiotics or prebiotics may help in preventing or curing experimental colitis, clinical trials have begun in IBD. This chapter focuses on the use of metronidazole and ciprofloxacin in CD and pouchitis. In addition, existing data on the use of other antimicrobial agents and on the potential for probiotics in IBD is reviewed.