Probiotic and postbiotic activity in health and disease: comparison on a novel polarised ex-vivo organ culture model.
Gut. 2012 Feb 1;
Authors: Tsilingiri K, Barbosa T, Penna G, Caprioli F, Sonzogni A, Viale G, Rescigno M
Abstract
Background and aimsProbiotics and their metabolic products, here called postbiotics, have been proposed as food supplements for a healthier intestinal homeostasis, but also as therapeutic aids in inflammatory bowel disease (IBD) with, however, very little clinical benefit. This may be due to the lack of reliable preclinical models for testing the efficacy of different strains.MethodsThe activity of three probiotic strains of Lactobacillus (or a postbiotic) was analysed and compared with a pathogenic strain of Salmonella on a novel organ culture system of human healthy and IBD intestinal mucosa developed in our laboratory. The system maintains an apical to basolateral polarity during stimulation due to the presence of a glued cave cylinder. The cylinder is detached at the end of the experiment and the tissue is processed for histology and immunohistochemistry. Cytokines released from the basolateral side are analysed.ResultsThe model system provides several physiological characteristics typical of a mucosal microenvironment including the presence of an organised mucus layer and an apical to basolateral polarity. Polarised administration of bacteria is critical to control the ensuing immune response as it mimics the physiological entrance of bacteria. The authors show that probiotics are not always beneficial for the healthy host and can also be detrimental in inflamed IBD. This study shows that a potent postbiotic can protect against the inflammatory properties of invasive Salmonella on healthy tissue and also downregulate ongoing inflammatory processes in IBD tissue.ConclusionsProbiotics can have inflammatory activities in both healthy and IBD tissue. Valid preclinical data on proper model systems should therefore be obtained before specific probiotic strains enter the clinics, especially if administered during acute inflammatory responses. Postbiotics may be a safe alternative for the treatment of patients with IBD in the acute inflammatory phase.
PMID: 22301383 [PubMed - as supplied by publisher]
Helicobacter pylori CagL dependent induction of gastrin expression via a novel αvβ5-integrin-integrin linked kinase signalling complex.
Gut. 2012 Jan 27;
Authors: Wiedemann T, Hofbaur S, Tegtmeyer N, Huber S, Sewald N, Wessler S, Backert S, Rieder G
Abstract
ObjectiveOne of the most important hormones in the human stomach is the peptide gastrin. It is mainly required for the regulation of gastric pH but is also involved in growth and differentiation of gastric epithelial cells. In Helicobacter pylori infected patients, gastrin secretion can be upregulated by the pathogen, resulting in hypergastrinaemia. H pylori induced hypergastrinaemia is described as being a major risk factor for the development of gastric adenocarcinoma.DesignIn this study, the upstream receptor complex and bacterial factors involved in H pylori induced gastrin gene expression were investigated, utilising gastric epithelial cells which were stably transfected with a human gastrin promoter luciferase reporter construct.ResultsIntegrin linked kinase (ILK) and integrin β5, but not integrin β1, played an important role in gastrin promoter activation. Interestingly, a novel CagL/integrin β5/ILK signalling complex was characterised as being important for H pylori induced gastrin expression. On interaction of H pylori with αvβ(5)-integrin and ILK, the epidermal growth factor receptor (EGFR) →Raf→mitogen activated protein kinase kinase (MEK)→extracellular signal regulated kinase (Erk) downstream signalling cascade was identified which plays a central role in H pylori gastrin induction.ConclusionThe newly discovered recognition receptor complex could be a useful target in treating precancerous conditions triggered by H pylori induced hypergastrinaemia.
PMID: 22287591 [PubMed - as supplied by publisher]
Interleukin-13 and transforming growth factor β synergise in the pathogenesis of human intestinal fistulae.
Gut. 2012 Jan 27;
Authors: Scharl M, Frei S, Pesch T, Kellermeier S, Arikkat J, Frei P, Fried M, Weber A, Jehle E, Rühl A, Rogler G
Abstract
ObjectiveEpithelial to mesenchymal transition (EMT) seems to play an important role in the pathogenesis of fistulae, a common clinical complication of Crohn’s disease (CD). TGFβ and interleukin-13 (IL-13) have been correlated with the onset of EMT-associated organ fibrosis and high levels of TGFβ have been shown in transitional cells (TCs) lining CD fistula tracts. This study investigated whether IL-13 could be involved in the pathogenesis of CD-associated fistulae.DesignProtein or mRNA levels in HT29 intestinal epithelial cells (IECs) or colonic lamina propria fibroblasts (CLPFs) were studied by western blotting or real-time PCR. CLPFs were isolated from non-inflammatory disease controls or patients with CD with or without fistulae and IL-13 levels were analysed in surgically removed fistula specimens by immunohistochemistry.ResultsTGFβ induced IL-13 secretion in CLPFs from patients with fistulising CD. In fistula specimens high levels of IL-13 were detected in TCs covering fistula tracts. In HT29 IEC monolayers, IL-13 induced SLUG and β6-integrin mRNA, which are associated with cell invasion. HT29 spheroids completely disintegrated when treated with TGFβ for 7 days, whereas IL-13-treated spheroids did not show morphological changes. Here, TGFβ induced mRNA expression of SNAIL1 and IL-13, whereas IL-13 elevated SLUG and β6-integrin mRNA. An anti-IL-13 antibody was able to prevent IL-13-induced SLUG expression in HT29 IECs.ConclusionsTGFβ induces IL-13 expression and an EMT-like phenotype of IECs, while IL-13 promotes the expression of genes associated with cell invasion. These findings suggest that TGFβ and IL-13 play a synergistic role in the pathogenesis of fistulae and inhibition of IL-13 might represent a novel therapeutic approach for fistula treatment.
PMID: 22287592 [PubMed - as supplied by publisher]
Prospective validation of an immunohistochemical panel (glypican 3, heat shock protein 70 and glutamine synthetase) in liver biopsies for diagnosis of very early hepatocellular carcinoma.
Gut. 2012 Jan 27;
Authors: Tremosini S, Forner A, Boix L, Vilana R, Bianchi L, Reig M, Rimola J, Rodríguez-Lope C, Ayuso C, Solé M, Bruix J
Abstract
Background and aimsConventional pathological analysis fails to achieve sufficient sensitivity and specificity for the diagnosis of hepatocellular carcinoma (HCC) in small nodules. Immunohistochemical staining for glypican 3 (GPC3), heat shock protein 70 (HSP70) and glutamine synthetase (GS) has been suggested to allow a confident diagnosis but no prospective study has established the diagnostic accuracy of this approach. The aim of this study is to assess prospectively the diagnostic accuracy of a panel of markers (GPC3, HSP70, GS) for the diagnosis of HCC in patients with cirrhosis with a small (5-20 mm) nodule detected by ultrasound screening.MethodsSixty patients with cirrhosis with a single nodule 5-20 mm newly detected by ultrasound were included in the study. Contrast-enhanced ultrasound, magnetic resonance and fine needle biopsy of the nodule (gold standard) were performed; the biopsy was repeated in case of diagnostic failures. Three consecutive sections of the first biopsy sample with meaningful material were stained with antibodies against GPC3, HSP70 and GS.ResultsForty patients were diagnosed with HCC. The sensitivity and specificity for HCC diagnosis were: GPC3 57.5% and 95%, HSP70 57.5% and 85%, GS 50% and 90%, respectively. The sensitivity and specificity of the different combinations were: GPC3+HSP70 40% and 100%; GPC3+GS 35% and 100%; HSP70+GS 35% and 100%; GPC3+HSP70+GS 25% and 100%. When at least two of the markers were positive (regardless of which), the sensitivity and specificity were 60% and 100%, respectively. Conventional pathological analysis yielded three false negative results, but the addition of this panel only correctly classified one of these cases as HCC.ConclusionThese data within a prospective study establish the clinical usefulness of this panel of markers for the diagnosis of early HCC. However, the panel only slightly increases the diagnostic accuracy in an expert setting.
PMID: 22287594 [PubMed - as supplied by publisher]
A basal gradient of Wnt and stem-cell number influences regional tumour distribution in human and mouse intestinal tracts.
Gut. 2012 Jan 27;
Authors: Leedham SJ, Rodenas-Cuadrado P, Howarth K, Lewis A, Mallappa S, Segditsas S, Davis H, Jeffery R, Rodriguez-Justo M, Keshav S, Travis SP, Graham TA, East J, Clark S, Tomlinson IP
Abstract
ObjectiveWnt signalling is critical for normal intestinal development and homeostasis. Wnt dysregulation occurs in almost all human and murine intestinal tumours and an optimal but not excessive level of Wnt activation is considered favourable for tumourigenesis. The authors assessed effects of pan-intestinal Wnt activation on tissue homeostasis, taking into account underlying physiological Wnt activity and stem-cell number in each region of the bowel.DesignThe authors generated mice that expressed temporally controlled, stabilised β-catenin along the crypt-villus axis throughout the intestines. Physiological Wnt target gene activity was assessed in different regions of normal mouse and human tissue. Human intestinal tumour mutation spectra were analysed.ResultsIn the mouse, β-catenin stabilisation resulted in a graduated neoplastic response, ranging from dysplastic transformation of the entire epithelium in the proximal small bowel to slightly enlarged crypts of non-dysplastic morphology in the colorectum. In contrast, stem and proliferating cell numbers were increased in all intestinal regions. In the normal mouse and human intestines, stem-cell and Wnt gradients were non-identical, but higher in the small bowel than large bowel in both species. There was also variation in the expression of some Wnt modulators. Human tumour analysis confirmed that different APC mutation spectra are selected in different regions of the bowel.ConclusionsThere are variable gradients in stem-cell number, physiological Wnt activity and response to pathologically increased Wnt signalling along the crypt-villus axis and throughout the length of the intestinal tract. The authors propose that this variation influences regional mutation spectra, tumour susceptibility and lesion distribution in mice and humans.
PMID: 22287596 [PubMed - as supplied by publisher]
Gender differences in oesophageal mucosal injury in a reflux oesophagitis model of rats.
Gut. 2012 Jan 27;
Authors: Masaka T, Iijima K, Endo H, Asanuma K, Ara N, Ishiyama F, Asano N, Koike T, Imatani A, Shimosegawa T
Abstract
ObjectiveThere is a strong male predominance of oesophageal adenocarcinoma, which might be related to the higher prevalence of precursor lesions such as erosive reflux oesophagitis in men compared with women. This experiment investigated the gender difference in a reflux oesophagitis model of rats and explored the potential role of oestrogen in controlling oesophageal tissue damage.DesignAn acid-reflux oesophagitis model was surgically produced in male and female rats, and ascorbic acid in the diet and sodium nitrite in the drinking water were administered to half of either group to provoke luminal exogenous nitric oxide (NO) as an exacerbating agent. Seven days after the surgery, the oesophagus was excised, and the injury area, myeloperoxidase activity and pro-inflammatory cytokine levels were measured. Furthermore, 17β-oestradiol was administered to ovariectomised female rats or male rats, which then underwent reflux oesophagitis surgery.ResultsWhile there was no gender difference in oesophageal damage in the baseline model, oesophageal damage was more intensively observed in males than in females in the presence of exogenous NO administration. While oesophageal damage was increased in ovariectomised rats compared with sham ovariectomised, exacerbated oesophageal damage was attenuated by the replacement of 17β-oestradiol. In addition, exacerbated oesophageal damage in male rats was suppressed by 17β-oestradiol.ConclusionThis is the first study showing the prominent gender difference in the severity of oesophageal tissue damage in a gastro-oesophageal reflux disease-related animal model, highlighting the critical involvement of oestrogen in controlling gastro-oesophageal reflux disease-related oesophageal epithelial injury.
PMID: 22287598 [PubMed - as supplied by publisher]
Hepatocyte growth factor/c-Met signalling is important for the selection of transplanted hepatocytes.
Gut. 2012 Jan 27;
Authors: Kaldenbach M, Giebeler A, Tschaharganeh DF, Erschfeld S, Wasmuth HE, Dolle L, Floege J, Trautwein C, Streetz KL
Abstract
BackgroundAt present hepatocyte transplantation is a promising option for cellular therapy of end-stage liver diseases. However, the underlying molecular mechanisms need to be better defined in order to translate this technique into clinical use. This study investigated the cursiv relevance of hepatocyte growth factor (HGF)/c-Met signalling for hepatocyte repopulation after transplantion.MethodsWild-type mice (c-Met(loxP/loxP)) and hepatocyte-specific conditional c-Met (HGF receptor) knockout (c-Met(Δhepa)) mice were used as donors and recipients for hepatocyte transplantation.ResultsTransplantation experiments revealed two major findings. First it was demonstrated that c-Met is indispensable in donor cells, as c-Met(Δhepa) cells did not repopulate recipient livers after transplantation. Second, genetic deletion of c-Met in recipient hepatocytes resulted in enhanced expansion of unmodified donor cells in host livers (up to 250-fold after 12 weeks). The relevant mechanisms for this observation in c-Met(Δhepa) host hepatocytes could be defined. c-Met(Δhepa) hepatocytes showed enhanced apoptosis, reduced cellular proliferation and a lack of AKT-kinase and STAT3 activation. In addition, tissue remodelling was changed in c-Met(Δhepa) recipient livers. Therefore, the lack of pro-proliferative transcription factors, increased apoptosis and changes in matrix-remodelling inhibit host cell proliferation in c-Met(Δhepa) recipient livers and thus favour repopulation of transplanted hepatocytes. Therapeutically liver repopulation could be increased through adenoviral expression of NK-4-an inhibitor of HGF signalling-in host hepatocytes.ConclusionHGF/c-Met plays a crucial role in host and donor cells of the liver for the cursiv selection of transplanted hepatocytes. Modulating HGF-dependent signalling seems a promising therapeutic option to favour expansion of transplanted hepatocytes.
PMID: 22287599 [PubMed - as supplied by publisher]
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