Helicobacter pylori-induced inflammation masks the underlying presence of low-grade dysplasia on gastric lesions.

BACKGROUND: Helicobacter pylori (H. pylori) infection has been associated with a long-term risk of precancerous gastric conditions (PGC) even after H. pylori eradication. AIM: To investigate the efficacy of High-Resolution White-Light Endoscopy with Narrow-Band Imaging in detecting PGC, before/after H. pylori eradication. METHODS: We studied 85 consecutive patients with H. pylori-related gastritis with/without PGC before and 6 mo after proven H. pylori eradication. Kimura-Takemoto modified and endoscopic grading of gastric intestinal metaplasia classifications, were applied to assess the endoscopic extension of atrophy and intestinal metaplasia. The histological result was considered to be the gold standard. The Sydney System, the Operative-Link on Gastritis-Assessment, and the Operative-Link on Gastric-Intestinal Metaplasia were used for defining histological gastritis, atrophy and intestinal metaplasia, whereas dysplasia was graded according to World Health Organization classification. Serum anti-parietal cell antibody and anti-intrinsic factor were measured when autoimmune atrophic gastritis was suspected. RESULTS: After H. pylori eradication histological signs of mononuclear/polymorphonuclear cell infiltration and Mucosal Associated Lymphoid Tissue-hyperplasia, disappeared or decreased in 100% and 96.5% of patients respectively, whereas the Operative-Link on Gastritis-Assessment and Operative-Link on Gastric-Intestinal Metaplasia stages did not change. Low-Grade Dysplasia prevalence was similar on random biopsies before and after H. pylori eradication (17.6% vs 10.6%, P = 0.19), but increased in patients with visible lesions (0% vs 22.4%, P < 0.0001). At a multivariate analysis, the probability for detecting dysplasia after resolution of H. pylori-related active inflammation was higher in patients with regression or reduction of Mucosal Associated Lymphoid Tissue hyperplasia, greater alcohol consumption, and anti-parietal cell antibody and/or anti-intrinsic factor positivity [odds ratio (OR) = 3.88, 95% confidence interval (CI): 1.31-11.49, P = 0.01; OR = 3.10, 95%CI: 1.05-9.12, P = 0.04 and OR = 5.47, 95%CI: 1.33-22.39, P < 0.04, respectively]. CONCLUSION: High-Resolution White-Light Endoscopy with Narrow-Band Imaging allows an accurate diagnosis of Low-Grade Dysplasia on visible lesions after regression of H. pylori-induced chronic gastritis. Patients with an overlap between autoimmune/H. pylori-induced gastritis may require more extensive gastric mapping.

Administration Timing Is the Best Clinical Outcome Predictor for Adalimumab Administration in Crohn's Disease.

Biological intervention for Crohn's Disease (CDs) patients, mainly using anti-TNF antibodies, is often an efficient therapeutic solution. Nonetheless, data defining the administration timing to maximize the chances of clinical remission are lacking. The objective of this "real-life" retrospective study was to evaluate if early Adalimumab (ADA) administration (<12 months) was an efficient strategy to improve patients' clinical outcome. This single center study included 157 CD patients, of which 80 received the first ADA administration within the first 12 months from the diagnosis. After 1 year of therapy, clinical remission was observed in 50.32% of patients, mucosal healing in 37.58%. Clinical remission was observed in 66.25% of the early ADA administration patients vs. 33.77% of the late (>12 months) (p < 0.001); mucosal healing was observed in 53.75% of the early vs. 20.78% of the late (p < 0.001). Dose escalation was required for 30.00% of the early vs. 66.23% of the late (<0.01). In the early ADA administration group, 7.50% patients were considered non-responders at the end of the follow-up vs. 22.08% patients in the late administration group. These findings highlighted that early ADA administration (within 1 year of diagnosis) improves the clinical response and mucosal healing, and reduces the loss of response rate and need for dose escalation.

Tumor microenvironment immune types in gastric cancer are associated with mismatch repair however, not HER2 status.

The treatment of patients with human epidermal growth factor receptor 2 (HER2)-negative gastric cancer is a major challenge. Immunotherapy using immune checkpoint inhibitors is a rapidly growing field. In a number of malignancy types it has been demonstrated that patients with mismatch repair deficiency efficiently respond to programmed death-ligand 1 (PD-L1) blockade therapy. Recent studies have evaluated tumor microenvironment immune types to predict which patients may clinically benefit from immunotherapy. The present study aimed to evaluate the immunohistochemical expression of PD-L1 in 70 gastric cancer tissue samples. Potential associations between PD-L1 expression and mismatch repair deficiency, HER2 and Epstein Barr virus (EBV) status were then investigated in the context of the tumor microenvironment. A positive association was identified for PD-L1 expression with mismatch repair deficiency and EBV status; however, no association was revealed with HER2 status. Immunohistochemistry was then used to classify the microenvironment immune types. This demonstrated that the majority of the gastric cancer samples (73%) belonged to the tumor microenvironment immune type II [PD-L1-/cluster of differentiation 8 (CD8)+ low], which involves an immune ignorant state and has a low sensitivity to immunotherapy. However, 7% of the gastric cancer cases were identified to belong to the tumor microenvironment immune type I (PD-L1+/CD8+ high), which exhibits adaptive immune escape responses and a high chance of reversion with immune checkpoint blockade therapy. In conclusion, the present study emphasized the importance of evaluating tumor microenvironment immune types, mismatch repair deficiency status and EBV status, rather than PD-L1 expression alone, when evaluating the eligibility of a patient for immunotherapy with anti-programmed cell death protein-1/PD-L1 antibodies.

Mucin phenotype of differentiated early gastric cancer: an immunohistochemistry study supporting therapeutic decision making.

Introduction: Endoscopic submucosal dissection is widely employed in early gastric cancer (EGC). Foveolar phenotypes should be distinguished from the other differentiated EGC (DEGC) types because of their increased malignant potential. The phenotypic classification could be useful not only for investigating EGC tumorigenesis but also for evaluating the tumor aggressiveness to guide treatment decision making. Methods: On surgical tissue specimens, we studied the mucin phenotype of EGC to distinguish cases with a worse prognosis dictating different therapeutic options or a very close surveillance program. DEGC in our series were classified as mucin foveolar (51%) or mucin intestinal (49%) phenotype. We evaluated correlations among foveolar and intestinal phenotypic markers, tumor patterns, clinicopathologic features and prognostic and therapeutic implications. Immunohistochemistry (IHC) for MUC5AC and CDX2 was performed on 63 EGC patient specimens. MUCA5C was employed as gastric foveolar phenotypic marker and CDX2 as intestinal phenotypic marker. Results: Foveolar DEGC was significantly associated with larger tumor size (p=0.01), high grade (G2-G3) (p=0.001), vessel permeation (p=0.05), lymph node metastasis (p=0.001) and ulceration (p=0.001), whereas intestinal type DEGC was associated with low grade (p=0.001). Conclusion: IHC determination of the mucin phenotype is an easy, inexpensive method that can provide useful, sensitive markers distinguishing the foveolar or intestinal phenotype in DEGC. The precise identification of the foveolar type, featuring a poorer prognosis, should sound a warning bell mandating very close study of the lesion before endoscopic treatment or contraindicating endoscopic resection in favor of the open surgery option.

PDGFRα expression as a novel therapeutic marker in well-differentiated neuroendocrine tumors.

AIMS: To evaluate the biological significance of dense vascular networks associated with low-grade NENs, we assessed the impact of PDGFRα tissue expression in 77 GEP/NEN patients, associating PDGFRα expression with the morphological characterization in low-grade tumors. METHODS AND RESULTS: Paraffin-embedded specimens of 77 GEP- NEN tissues, collected from January 2006 to March 2018, were evaluated for PDGFRα tissue expression and correlations with clinicopathological characteristics. PDGFRα tissue expression was significantly correlated with grade and the NEN growth pattern (p < 0.001) but not with gender, primary site or lymph nodes metastatic status. PDGFRα staining was mainly localized in the vascular pole of the neuroendocrine cells and in Enterochromaffin (EC) cells. In particular PDGFRα tissue expression was significantly more expressed in G2 (p < 0.001) than G1 and G3 cases (p 0.004; p < 0.0002;) and correlated with an insular growth pattern. PDGFRα tissue expression was associated with the Ki67 index and we found a significant negative trend of association with the Ki67 proliferation index (P < 0.001): thus PDGFRα expression is referred to morphological and not to proliferative data. CONCLUSIONS: PDGFRα represents an effective target for new anti-angiogenic treatment in WD- GEP-NENs, in particular in G2 cases, and in G3 cases only when there is a mixed insular-acinar pattern. In this context, it is important to carefully delineate those tumors that might better respond to this type of treatment alone or in combination. Further investigation of the relationship between PD-L1 and PDGFRa is warranted, and may contribute to optimize the therapeutic approach in patients with GEP-NENs.

Increased nerve twigs in small intestinal mucosa with programmed cell death-ligand 1 and somatostatin receptor type 2A expression in recurrent Crohn disease: A case report.

RATIONALE: Inflammatory bowel disease (IBD) patients manifest symptoms of disturbed gut function, such as neural sensory-motor changes. Programmed cell death-ligand 1 (PD-L1), normally present in neural tissue, exists in close apposition to the mucosal immune system and intestinal epithelium, and a bi-directional communication is known to occur at these interfaces. Somatostatin has been shown to suppress the inflammatory reaction, and has been used in several clinical trials to treat inflammatory disorders, such rheumatoid arthritis. Recently, somatostatin receptor type 2A, that regulates neurotransmission, proliferation, and apoptosis, has been recognized in IBD. Although prominent abnormalities in the morphology of the enteric nervous system have been observed in idiopathic IBD, they are more marked in Crohn disease. PATIENT CONCERNS: A 55-year-old woman with recurrent Crohn disease, just surgically treated for ileal resection, have a stenotic complication. INTERVENTIONS: At surgery 5 cm of preterminal ileum with stenosis and anastomotic ileocolic block was removed. DIAGNOSES: The histopathology showed a recurrent Crohn in fistulo-stenotic phase; the stenosis was mainly sustained by mass-forming, ganglioneuromatous hyperplasia. Normally very rare, fine nerve twigs extend up into mucosa but we found a new-formed fibrillary network, extending into the inflammation area at the subepithelial luminal site of the mucosa, that was positive to PD-L1 and somatostatin receptor type 2A (SSTR2A) immunostaining but not visualized in routinary stained slides. OUTCOMES: After surgery the patient was semestrally followed with clinical endoscopic evaluation that results uneventfully. LESSONS: Our case shows that before surgery neuromatous abnormalities can be predicted by immunostained new-formed twigs in the mucosa.

Galunisertib modifies the liver fibrotic composition in the Abcb4Ko mouse model.

Transforming growth factor (TGF)-ß stimulates extracellular matrix (ECM) deposition during development of liver fibrosis and cirrhosis, the most important risk factor for the onset of hepatocellular carcinoma. In liver cancer, TGF-ß is responsible for a more aggressive and invasive phenotype, orchestrating remodeling of the tumor microenvironment and triggering epithelial-mesenchymal transition of cancer cells. This is the scientific rationale for targeting the TGF-ß pathway via a small molecule, galunisertib (intracellular inhibitor of ALK5) in clinical trials to treat liver cancer patients at an advanced disease stage. In this study, the hypothesis that galunisertib modifies the tissue microenvironment via inhibition of the TGF-ß pathway is tested in an experimental preclinical model. At the age of 6 months, Abcb4ko mice-a well-established model for chronic liver disease development and progression-are treated twice daily with galunisertib (150 mg/kg) via oral gavage for 14 consecutive days. Two days after the last treatment, blood plasma and livers are harvested for further assessment, including fibrosis scoring and ECM components. The reduction of Smad2 phosphorylation in both parenchymal and non-parenchymal liver cells following galunisertib administration confirms the treatment effectiveness. Damage-related galunisertib does not change cell proliferation, macrophage numbers and leucocyte recruitment. Furthermore, no clear impact on the amount of fibrosis is evident, as documented by PicroSirius red and Gomori-trichome scoring. On the other hand, several fibrogenic genes, e.g., collagens (Col1α1 and Col1α2), Tgf-ß1 and Timp1, mRNA levels are significantly downregulated by galunisertib administration when compared to controls. Most interestingly, ECM/stromal components, fibronectin and laminin-332, as well as the carcinogenic ß-catenin pathway, are remarkably reduced by galunisertib-treated Abcb5ko mice. In conclusion, TGF-ß inhibition by galunisertib interferes, to some extent, with chronic liver progression, not by reducing the stage of liver fibrosis as measured by different scoring systems, but rather by modulating the biochemical composition of the deposited ECM, likely affecting the fate of non-parenchymal cells.

PD-L1 expression in colorectal cancer defines three subsets of tumor immune microenvironments.

OBJECTIVES: We investigated the PD-L1 expression in colorectal cancer (CRC) and in its microenvironment. RESULTS: PD-L1 was expressed in neoplastic cells (NCs) and tumor-infiltrating immune cells (IICs). All samples PD-L1+ on NCs were also on IICs. Three types of cancers could be grouped: group A(NCs-/ IICs-); group B (NCs-/ IICs+); group C (NCs+/IICs+). To group A belong tumors characterized by poorly immunogenic competence, poor immune response but massive granulocyte infiltrate, justifying the absence of PD-L1 as an immunoinhibitor receptor. To Group B probably belong more immunogenic CRCs, justifying the strong IICs-mediated immune response, and up-regulation of PD-L1 expression only on IICs. To group C belong CRCs probably characterized by a large amount of tumor neoantigens resulting in a marked infiltration of lymphocytes and PD-L1 upregulation also in NCs. MATERIALS AND METHODS: Sixty-three colorectal cancer specimens from a cohort of 61 patients were retrospectively reviewed. Thirty-seven MSS and 26 MSI-H CRCs enrolled in this study. Immunohistochemical staining to PD-L1 was performed by using MAb E1L3N. CONCLUSIONS: Our study calls attention to the importance to assess PD-L1 expression in tumor microenvironment also evaluating type and density of infiltrating immune cells to better stratify CRCs with different immunological patterns.

Role of PD-L1 expression as a biomarker for GEP neuroendocrine neoplasm grading.

Neuroendocrine neoplasms (NENs) are rare, heterogeneous and ubiquitous tumors commonly localized in the gastrointestinal tract, lung, and pancreas. The clinical behavior of NEN is highly unpredictable; in fact, low-grade cases can unexpectedly be associated with metastases. Currently, the 2010 WHO NEN classification employs histological differentiation and the proliferation index for grading tumors but fails to provide reliable prognostic and therapeutic indications. Therefore, there is an urgent need for a better characterization of G2/G3 NENs. Similar to several other tumors, NENs possess immune-escape mechanisms, but very little has yet been done to characterize this crucial aspect. There are no available data describing PD-L1 expression in these tumors. Here we provide, for the first time, evidence of PD-L1 tissue expression in gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs). PD-L1 expression was significantly associated with a high-grade WHO classification (G3) (P<0.001) but not with gender, primary site, or lymph node status. The PD-L1 positivity rate and signal intensity are directly correlated (P<0.001) with a grade increase from G1 to G3. In particular in G3 cases, we observed a dichotomy between the morphology (WD- and PD-NENs) and Ki67. Moreover, our study demonstrated a significant association with the grade and PD-L1 expression levels in immune-infiltrating cells (P<0.001). In particular, G3 tumors are characterized by strong PD-L1 expression in both the tumor and infiltrating immune cells (P<0.001), reflecting an unfavorable environment for T-cell-mediated tumor aggression. These findings suggest that NENs might acquire resistance to immune surveillance by upregulating PD-L1 and inhibiting peritumoral and intratumoral infiltrating lymphocytes. Here we demonstrate that PD-L1 is currently the best-known biomarker for G3 NENs, becoming the new gold standard for G3 NEN discrimination. Furthermore, pharmacological approaches using anti-PD-1 antibodies may become the logical choice for the treatment of G3 cases with a poor prognosis.

Dendritic Cells Modulate Iron Homeostasis and Inflammatory Abilities Following Quercetin Exposure.

BACKGROUND: Fruits and vegetables are rich in plant polyphenols, whose consumption is encouraged in healthy dietary regimes due to their antioxidants and anti-inflammatory effects. These organic molecules exhibit numerous properties including phylochelation; the ability to complex metal ions, including highly reactive iron. Among polyphenols, we focused our attention on quercetin that previously demonstrated its ability to reduce dendritic cells (DCs) inflammatory cytokine secretion and antigen presentation following LPS exposure. Dendritic cell inflammatory response is also associated with modulation of several iron metabolism related genes. OBJECTIVE: To characterize the axis between quercetin exposure and iron extracellular transport that may explain polyphenol anti-inflammatory abilities. METHOD: Bone marrow derived DCs were exposed to 25µM of quercetin on day 7 and treated with 1 µg/mL of LPS on day 8. The relation between quercetin exposure and the expression level of genes involved in iron homeostasis was addressed by qPCR. The axis between iron export and quercetin exposure was confirmed in vitro and in vivo using quercetin gavage and quercetin-enriched diet. RESULTS: Here we demonstrate that DCs, exposed to quercetin, activate a pattern of genes that increase extracellular iron export, resulting in an overall decrease in the intracellular iron content and consequent diminished inflammatory abilities. This DCs phenotype is consistent with anti-inflammatory phenotype of the mucosal resident DCs, the ones most commonly exposed to polyphenols. CONCLUSIONS: Iron balance is a crucial checkpoint for DCs inflammatory abilities. Quercetin-enriched nutritional regimes that favor DCs extracellular iron transport could reduce the incidence of chronic inflammatory syndromes.

Secretory leukoprotease inhibitor is required for efficient quercetin-mediated suppression of TNFα secretion.

Dendritic cells (DCs) are professional antigen presenting cells (APCs) that in response to microbial infections generate long-lasting adaptive immune response. Following microbial uptake, DCs undergo a cascade of cellular differentiation that ultimately leads to "mature" DCs. Mature DCs produce a variety of inflammatory cytokines, including tumor necrosis factor-α (TNFß) a key cytokine for the inflammatory cascade. In numerous studies, polyphenols, including quercetin, demonstrated their ability to suppress TNFα secretion and protect from the onset of chronic inflammatory disorders. We show that murine bone marrow derived DCs express Slpi following quercetin exposure. Slpi is known to suppress LPS mediated NFκB activation, thus, it was hypothesized that its expression could be the key step for polyphenol induced inflammatory suppression. Slpi-KO DCs poorly respond to quercetin administration failing to reduce TNFα secretion in response to quercetin exposure. Supernatant from quercetin exposed DCs could also reduce LPS-mediated TNFα secretion by unrelated DCs, but this property is lost using an anti-Slpi antibody. In vivo, oral administration of quercetin is able to induce Slpi expression. Human biopsies from inflamed tract of the intestine reveal the presence of numerous SLPI+ cells and the expression level could be further increased by quercetin administration. We propose that quercetin induces Slpi expression that in turn reduces the inflammatory response. Our data encourages the development of nutritional strategies to improve the efficiency of current therapies for intestinal chronic inflammatory syndrome and reduce the risks of colorectal cancer development.

Tissue expression of glycated apolipoprotein B in colorectal adenoma and cancer.

BACKGROUND: Myocardial infarction and colorectal cancer are associated at the population level and in autoptic studies. Glycated apolipoprotein B (apoB) is a risk factor for the development of myocardial infarction. The association of glycated apoB with dysplastic and neoplastic colorectal tissue was investigated. MATERIALS AND METHODS: Forty-eight consecutive surgical specimens, 26 colorectal adenomas and 22 colorectal carcinomas, retrieved from the archives of the Pathologic Anatomy Department of our institution, were examined. The tissue content of glycated apoB was determined using a monoclonal antibody. RESULTS: Glycated apoB was detected in 27% of the adenomas and 45% of the cancer tissue, but only in 18% of the normal tissue near the cancer site. CONCLUSION: Glycated apoB is associated with dysplastic and even more so with neoplastic cancer tissue.

KRAS genotyping as biomarker in colorectal cancer: a comparison of three commercial kits on histologic material.

BACKGROUND/AIM: The crucial role of KRAS status in new colorectal cancer target therapy raises the issue regarding which testing method to use. This study analysed 112 formalin fixed, paraffin-embedded (FFPE) metastatic tissue samples using three different commercially available kits. PATIENTS AND METHODS: A group of 40 KRAS wild-type (wt), 40 codon 12-mutated and 32 codon-13 mutated samples, previously evaluated by real-time PCR (TheraScreen kit), used as reference method, were analysed by Ampli-set-K-RAS and K-RAS StripAssay kit (herein called kit A and B, respectively) based on two different technologies. RESULTS: The sensitivity of both kits was 92.5% for wt samples, 100% and 95.0% for kit A and B, respectively for samples mutated in codon 12. The specificity was 100% for both kits for all groups of samples. After a minor modification of the kit A method, its specificity reached 100%. CONCLUSION: of low cost and easy to use, kit A may be suitable for use in a routine diagnostic setting.

Assessment of estrogen receptors and apoptotic factors in cryopreserved human ovarian cortex.

The aims of this study were: (i) to examine frozen-thawed ovarian tissues for features of follicular health and atresia by histology; (ii) to assess the expression of estrogen receptors alpha (ERalpha) and beta (ERbeta) by real-time PCR; (iii) to evaluate the Bax/Bcl-2 ratio, as an apoptotic index, in the ovarian tissues before and after cryopreservation. Ovarian cortical biopsies were obtained from 11 patients. The fragments were subdivided into two groups, fresh (control tissues) and cryopreserved tissues obtained by direct plunging into liquid nitrogen. Both tissue groups were subjected to a histological evaluation of the healthy and atretic follicles, immunohistochemical localization of the ER, and a real-time PCR (qPCR) to evaluate the expression of ER, Bax, Bcl-2 as well as beta-actin, as control gene. Damage was observed in 31% of primordial, 45% of primary, and 75% of secondary follicles in the cryopreserved tissue group. The qPCR analysis showed that the level of ERbeta was greater in fresh than cryopreserved tissues, whereas the ERalpha expression and Bax/Bcl-2 ratio were similar in both tissue groups. A significant inverse association was observed between ERalpha mRNA levels in the fresh tissue group and subjects' ages. The results show that cryopreservation and thawing of human ovarian tissue does not affect the morphology of primordial or primary follicles and that cryopreservation does not affect apoptosis. However, cryopreservation seems to have an inhibitory effect on the level of ERbeta. Additional studies are needed to evaluate the differential effects of freezing follicles at different stages of follicular development and ovarian steroidogenesis.

EGFR-targeted therapy in colorectal cancer: does immunohistochemistry deserve a role in predicting the response to cetuximab?

The EGF receptor (EGFR) has emerged as a rational target for anticancer therapy for the treatment of colorectal cancer (CRC). Positive immunohistochemistry (IHC) staining for EGFR is used as a criterion for patient selection; however, doubt has been cast on the utility of this method. Not only is the response to cetuximab, an anti-EGFR mAb, low in patients expressing EGFRs, but a similar response to cetuximab has also been described in patients who do not express EGFRs. This review aims to evaluate the possible cause of the lack of correlation between the efficacy of cetuximab and EGFR IHC staining in CRC, as well as any modifications in the IHC method necessary to optimize patient selection for cetuximab therapy. In our opinion, the heterogeneous expression of the receptor in the neoplastic population and the inability of the mAbs used to predict the response to cetuximab could be the major cause of the failure of IHC staining as a reliable tool for patient selection. The use of specific mAbs directed against the phosphorylated and mutant form (EGFRvIII) of the EGFR could reinstate IHC as a valid predictor of response to therapy.

Parallel intestinal and liver injury during early cholestasis in the rat: modulation by bile salts and antioxidants.

Whereas long-term cholestasis results in intestinal alterations and increased permeability to hepatotoxins, the effect of short-term cholestasis is less known and was investigated in bile duct ligated (BDL) rats. In the intestinal mucosa, at Day 7 BDL, total glutathione and protein sulfhydryl contents had decreased, oxidized glutathione levels increased (P<0.05 vs baseline), and a reduced epithelium thickness with dissolving crypt phenomena was observed in 40% of rats. At Day 10, total protein content, glutathione-related enzyme activities, and the transmural electrophysiological activity had decreased (-50%); by contrast, oxidized proteins doubled (P<0.05), and histological changes were extended to 70% of rats. In vitro exposure to taurodeoxycholate at micellar concentrations determined dysepithelization in normal gut but dissolving crypt phenomena and necrosis in cholestatic bowels. In the liver, ongoing cholestasis was associated with early oxidative changes especially in mitochondria, where protein sulfhydryls were decreased and negatively correlated with glutathione-protein mixed disulfides (r=-0.807, P<0.001). Daily oral administration of tauroursodeoxycholate, a hydrophilic bile salt, and glutathione to BDL rats improved intestinal histology, function, and redox state. In conclusion, short-term cholestasis results in distinctive functional, oxidative, and morphological changes of intestinal mucosa, determined increased vulnerability to toxic injury, and parallel hepatic oxidative damage.

Immunohistochemical mismatch repair proteins expression in colorectal cancer.

Immunohistochemical (IHC) assessment of the mismatch repair proteins has been proposed as an alternative strategy to molecular biology for evaluating the unstable phenotype of tumors. With the aim of introducing IHC analysis as a routine diagnostic test, the authors compared the expression of MLH1 and MSH2 proteins with a PCR-based microsatellite assay. The concordance rate between the two methods was 90% after IHC evaluation of two different areas of each tumor. These results show that IHC may be as efficient as PCR in detecting unstable phenotype by using only one surgical or biopsy sample.

Effects of probiotic bacteria (VSL#3) on the polyamine biosynthesis and cell proliferation of normal colonic mucosa of rats.

BACKGROUND: Probiotics seem to possess tumour inhibitory properties, but few studies have investigated their actions on the cell proliferation of normal colonic mucosa. The effects of a probiotic mixture (VSL#3) on polyamine biosynthesis, Ki-67 levels and apoptosis in the normal colon of rats were studied. MATERIALS AND METHODS: For a 4-week period, 20 rats were fed a VSL#3 solution and 20 rats a saline solution. Samples from the colonic mucosa were collected at the end of treatment. Polyamines were detected by HPLC, ornithine decarboxylase activity by a radiometric technique, and apoptosis and Ki-67 by histochemical and immunohistochemical methods. RESULTS: VSL#3 caused a significant decrease in colonic polyamine levels, ornithine decarboxylase activity and Ki-67 compared to controls. A significant increase in the apoptotic index was also observed. CONCLUSION: Probiotics could also reduce proliferation rates in a condition not affected by hyperproliferative or neoplastic growth, when the normal control mechanisms are still completely effective.

The influence of Lactobacillus brevis on ornithine decarboxylase activity and polyamine profiles in Helicobacter pylori-infected gastric mucosa.

BACKGROUND: Functional probiotics may prevent Helicobacter pylori infection, and some evidence suggests that they also possess antitumor properties. Lactobacillus brevis (CD2) is a functional Lactobacillus strain with peculiar biochemical features, essentially related to the activity of arginine deiminase. This enzyme catalyzes the catabolism of arginine and affects the biosynthesis of polyamines (putrescine, spermidine, and spermine). Polyamines are polycations found in high concentrations in both normal and neoplastic cells. Our aims were: 1, to assess whether oral administration of L. brevis (CD2) affects H. pylori survival in the human gastric mucosa; 2, to evaluate the effects of L. brevis (CD2) on polyamine biosynthesis in gastric biopsies from H. pylori-positive patients. MATERIALS AND METHODS: For 3 weeks before endoscopy, 22 H. pylori-positive dyspeptic patients randomly received (ratio 1 : 1) high oral doses of L. brevis (CD2) or placebo. Before and after treatment, H. pylori infection was determined by urea breath test (UBT). In gastric biopsies, ornithine decarboxylase activity and polyamine levels were, respectively, evaluated by a radiometric technique and high-pressure liquid chromatography (HPLC). RESULTS: L. brevis (CD2) treatment did not eradicate H. pylori. However, a reduction in the UBT delta values occurred, suggesting a decrease in intragastric bacterial load. Significantly, L. brevis (CD2) induced a decrease in gastric ornithine decarboxylase activity and polyamine levels. CONCLUSIONS: Our data support the hypothesis that L. brevis (CD2) treatment decreases H. pylori colonization, thus reducing polyamine biosynthesis. Alternatively, the arginine deiminase activity following L. brevis (CD2) administration might cause arginine deficiency, preventing polyamine generation from gastric cells.