Intraepithelial and lamina propria leucocyte subsets in inflammatory bowel disease: an immunohistochemical study of colon and rectal biopsy specimens

Relationship between Undernutrition and Anemia in Patients with Ulcerative Colitis

This study aimed to assess the relationship between malnutrition and anemia in patients with ulcerative colitis (UC). The cross-sectional retrospective study included 80 patients with UC. Body mass index and total body fat mass were derived retrospectively from bioimpedance measurements. Anemia was diagnosed retrospectively according to WHO criteria. A binary logistic regression was performed to study the relationship between nutritional status parameters and anemia, and adjusted for demographic and disease-associated characteristics. The prevalence of anemia in the study population was 40.0%. Among all included patients, 86.3% had acute disease corresponding to S1–S3 disease behavior. In the adjusted binary logistic model, total serum protein level below 64 g/L and low body fat percentage were associated with high odds for the of development of anemia, with odds ratios of 5.1 (95% CI 1.5; 17.8; p = 0.01) and 8.5 (95% CI 1.1; 63.6; p = 0.037), respectively. The adjusted model included sex, age, disease activity, extent of gut involvement, quantity of relapses from disease onset, and treatment with immunosuppressive drugs as confounders. Hypoproteinemia and low body fat percentage were associated with anemia in patients with UC. These results suggested that undernutrition may be involved as one of the causative factors of anemia in UC.

Correlation of cholesteryl ester metabolism to pathogenesis, progression and disparities in colorectal Cancer

Background

Colorectal cancer (CRC) is one of the most common cancers worldwide characterized by disparities in age, gender, race and anatomic sites. The mechanism underlying pathogenesis, progression and disparities of CRC remains unclear. This study aims to reveal the association of expression levels of enzymes related to cholesteryl ester (CE) metabolism with pathogenesis, progression and disparities of CRC.

Methods

The differences in gene expression levels were analyzed for enzymes in CE synthesis (acyl CoA: cholesterol acyltransferase 1 and 2, ACAT1, and ACAT2), and in CE hydrolysis (neutral cholesterol ester hydrolase, NCEH1 and lysosomal acid lipase, LAL) on TNMplot platform between CRC and normal colorectal tissues (NCT) in a large cohort. The differences in protein expression levels for these enzymes were determined by Immunochemistry (IHC) performed on tissue microarray containing 96 pairs of CRC and benign colorectal tissues (BCT) from different patient populations. The expression level represented as IHC score of each enzyme was compared between CRC and BCT in entire population and populations stratified by race, gender and anatomic sites. Student’s t-test, Fisher exact test and ANOVA were used for data analysis. Significant p value was set at P<0.05.

Results

The gene expression level of ACAT1 was significantly lower in CRC than in NCT (P = 2.15e-119). The gene expression level of ACAT2 was not statistically different between CRC and NCT. The gene expression level of LIPA (encoding LAL) was significantly higher in CRC than in NCT (P = 2.01e-14). No data was found for the gene expression level of NCEH1. The IHC score of ACAT1was significantly lower in CRC than in BCT in all studied populations and in sub site of colon, but not in that of rectum. The IHC score of ACAT2 was not statistically different between CRC and BCT. IHC score of NCEH1 was significantly higher in CRC than in BCT only in African American (AA) population. The IHC score of LAL was significantly higher in CRC than in BCT in all studied populations and in all sub sites. In addition, decreased ACAT1 in CRC significantly correlated to progression of CRC: the lower IHC score of ACAT1, the more advanced clinical stage of CRC will be.

Conclusions

This study revealed that altered expression levels in enzymes related to CE metabolism highly correlate to the pathogenesis, clinical progression and disparities of CRC. The results will add revenue in elucidating mechanisms underlying progression of CRC, and shed light on seeking biomarkers and exploring therapeutic targets for CRC in a new direction.

Sex- and corticotropin-releasing factor receptor 2- dependent actions of urocortin 1 during inflammation

We investigated whether corticotropin-releasing factor receptor 2 (CRF2) and its high-affinity agonist urocortin 1 (Ucn1) mediate sex-specific signaling and immune responses. Intrarectal trinitrobenzene sulfonic acid was used to induce experimental colitis in wild-type, CRF2 knockout (CRF2KO), and heterozygous (CRF2Ht) mice of both sexes. Changes in plasma extravasation, organ weight, survival, immune cell numbers, inflammatory cytokines, and the MAPK signaling pathway were assessed. Stored intestinal biopsies from patients with Crohn's disease (CD) and age- and sex-matched individuals without inflammatory bowel disease (IBD) were examined by immunofluorescence and confocal microscopy to characterize Ucn1 and CRF receptor expression. CRF2Ht mice of both sexes showed decreased survival during colitis compared with other genotypes. Ucn1 improved survival in male mice alone. Ucn1 restored colon length and spleen and adrenal weight and decreased colonic TNF-α, IL-6, and IL-1β levels in male CRF2Ht mice alone. CRF2Ht mice of both sexes showed decreased phosphorylation of MAPK p38 and heat shock protein 27 (Hsp27) levels. Ucn1 restored p-Hsp27 levels in male CRF2Ht mice alone. Expression of the chaperone protein Hsp90 decreased during colitis, except in male CRF2Ht mice. Taken together, our data indicate that sex shows significant interaction with genotype and Ucn1 during colitis. Human duodenal and colonic biopsies revealed that sex-specific differences exist in levels of CRF receptors and Ucn1 expression in patients with CD compared with the matched non-IBD subjects. To conclude, Ucn1 mediates sex-specific immune and cellular signaling responses via CRF2, emphasizing the need for inclusion of females in preclinical studies.

Endoplasmic reticulum stress response promotes cytotoxic phenotype of CD8αβ+ intraepithelial lymphocytes in a mouse model for Crohn's disease-like ileitis

Endoplasmic reticulum (ER) unfolded protein responses (UPR) are implicated in the pathogenesis of inflammatory bowel disease. Cytotoxic CD8αβ(+) intraepithelial lymphocytes (IEL) contribute to the development of Crohn's disease-like ileitis in TNF(ΔARE/+) mice. In this study, we characterized the role of ER-UPR mechanisms in contributing to the disease-associated phenotype of cytotoxic IEL under conditions of chronic inflammation. Inflamed TNF(ΔARE/+) mice exhibited increased expression of Grp78, ATF6, ATF4, and spliced XBP1 in CD8αβ(+) IEL but not in CD8αα(+) IEL or in lamina propria lymphocytes. Chromatin immunoprecipitation analysis in CD8αβ(+) T cells showed selective recruitment of ER-UPR transducers to the granzyme B gene promoter. Heterozygous Grp78(-/+) mice exhibited an attenuated granzyme B-dependent cytotoxicity of CD8αβ(+) T cells against intestinal epithelial cells, suggesting a critical activity of this ER-associated chaperone in maintaining a cytotoxic T cell phenotype. Granzyme B-deficient CD8αβ(+) T cells showed a defect in IL-2-mediated proliferation in Grp78(-/+) mice. Adoptively transferred Grp78(-/+) CD8αβ(+) T cells had a decreased frequency of accumulation in the intestine of RAG2(-/-) recipient mice. The tissue pathology in TNF(ΔARE/+) × Grp78(-/+) mice was similar to TNF(ΔARE/+) mice, even though the cytotoxic effector functions of CD8αβ(+) T cells were significantly reduced. In conclusion, ER stress-associated UPR mechanisms promote the development and maintenance of the pathogenic cytotoxic CD8αβ(+) IEL phenotype in the mouse model of Crohn's disease-like ileitis.

Partial replacement of dietary (n-6) fatty acids with medium-chain triglycerides decreases the incidence of spontaneous colitis in interleukin-10-deficient mice

Enteral nutrition has a primary therapeutic effect in active Crohn's disease. It is unknown which nutrient(s) account for this action, but a role for both the amount and type of dietary fat has been postulated. Some clinical and experimental data suggest that medium-chain triglycerides (MCT) may reduce intestinal inflammation. We aimed to assess the effect of replacing part of the dietary fat with MCT on the incidence and severity of colitis in interleukin (IL)-10(-/-) mice under specific pathogen-free conditions. Twenty-four IL-10(-/-) 4-wk-old mice were randomized to receive a control diet based on sunflower oil [(n-6) fatty acids (FA)] and an experimental isocaloric, isonitrogenous diet with 50% sunflower and 50% coconut oil (MCT diet). When the mice were 12 wk old, they were killed and the colon was examined for the presence of colitis, lymphocyte subpopulations and apoptosis, ex vivo cytokine production in supernatant of colon explants, toll-like receptor (TLR)-2 and TLR-9 mRNA, and FA profile in colonic tissue homogenates. Colitis incidence was lower in the IL-10(-/-) mice fed the MCT diet (1/12) than in the mice fed the control diet (8/12; P = 0.03). The histological damage score was also lower in the former (P < 0.0005). Feeding the MCT diet resulted in fewer total and apoptotic intraepithelial CD3+ and lamina propria CD3+CD4+ lymphocytes, as well as downregulated production of IL-6 and interferon-gamma, and reduced TLR-9 mRNA. We conclude that partial replacement of dietary (n-6) FA with MCT decreases the incidence of colitis in a model of spontaneous intestinal inflammation and provide experimental arguments for a possible primary therapeutic effect of MCT in human Crohn's disease.

Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis in irritable bowel syndrome

Enhanced stress responsiveness has been implicated as a potential mechanism contributing to the pathophysiology of irritable bowel syndrome (IBS), and should be reflected in altered function of the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system. Both of these systems can modulate mucosal immune function. The aims of this study were: (i) to characterize the basal circadian rhythm of adrenocorticotropin hormone (ACTH) and cortisol in IBS vs healthy controls; (ii) to compare stimulated ACTH, cortisol and noradrenaline responses to a pelvic visceral stressor (sigmoidoscopy) in IBS and controls; and (iii) to correlate neuroendocrine responses with colonic mucosal cytokine expression and symptoms in IBS. Two separate studies were conducted in women. In Study 1, basal cortisol levels were analysed in 41 IBS and 25 controls using 24-h collections of plasma ACTH and cortisol (q10 min sampling). In Study 2, 10 IBS patients with diarrhoea (IBS-D) and 10 controls underwent sigmoidoscopy with measurements of stimulated neuroendocrine responses and cytokine mRNA expression in colonic tissue. Basal ACTH levels were significantly blunted (P < 0.05), while basal and stimulated plasma cortisol levels were higher in patients. Basal cortisol levels prior to an experimental visceral stressor positively correlated with anxiety symptoms (P < 0.004), but not IBS symptoms. Irritable bowel syndrome patients with diarrhoea had significantly decreased mRNA expression of mucosal cytokines [interleukin (IL)-2, IL-6] in the sigmoid colon vs controls (P < 0.05). Although dysregulations in stress-responsive systems such as the HPA axis and mucosal immune function are demonstrated in IBS, they do not appear to have a primary role in modulating IBS severity and abdominal pain.

Local radiotherapy of exposed murine small bowel: apoptosis and inflammation

Background

Preoperative radiotherapy of the pelvic abdomen presents with complications mostly affecting the small bowel. The aim of this study was to define the features of early radiation-induced injury on small bowel.

Methods

54 mice were divided into two groups (36 irradiated and 18 sham irradiated). Animals were placed on a special frame and (in the radiated group) the exteriorized segment of ileum was subjected to a single absorbed dose of 19 or 38 Gy radiation using 6 MV high energy photons. Specimens were collected for histology, immunohistochemistry (IHC) and ELISA analysis after 2, 24 and 48 hours. Venous blood was collected for systemic leucocyte count in a Burker chamber.

Results

Histology demonstrated progressive infiltration of inflammatory cells with cryptitis and increased apoptosis. MIP-2 (macrophage inflammatory protein) concentration was significantly increased in irradiated animals up to 48 hours. No significant differences were observed in IL-10 (interleukin) and TNF-α (tumour necrosis factor) levels. IHC with CD45 showed a significant increase at 2 hours of infiltrating leucocytes and lymphocytes after irradiation followed by progressive decrease with time. Caspase-3 expression increased significantly in a dose dependent trend in both irradiated groups up to 48 hours.

Conclusion

Acute small bowel injury caused by local irradiation is characterised by increased apoptosis of crypt epithelial cells and by lymphocyte infiltration of the underlying tissue. The severity of histological changes tends to be dose dependent and may affect the course of tissue damage.

Gene expression in mononuclear cells from patients with inflammatory bowel disease

OBJECTIVES

Discovery of Nod2 as the inflammatory bowel disease 1 (IBD1) susceptibility gene has brought to light the significance of mononuclear cells in inflammatory bowel disease pathogenesis. The purpose of this study was to examine changes in gene expression in peripheral blood mononuclear cells in patients with untreated Crohn's disease (CD) and ulcerative colitis (UC) as compared to patients with other inflammatory gastrointestinal disorders and to healthy controls.

METHODS

We used a 2400 gene cDNA glass slide array (MICROMAX) to examine gene expression in peripheral blood mononuclear cells from seven patients with Crohn's disease, five patients with ulcerative colitis, 10 patients with other inflammatory gastrointestinal disorders, and 22 age- and sex-matched controls. Results. Novel categories of genes differentially expressed in Crohn's disease and ulcerative colitis patients included genes regulating hematopoietic cell differentiation and leukemogenesis, lipid raft-associated signaling, the actin cytoskeleton, and vesicular trafficking.

CONCLUSIONS

Altered gene expression in mononuclear cells may contribute to inflammatory bowel disease pathogenesis.

Differentiation between ulcerative colitis and Crohn's disease by a quantitative immunohistochemical evaluation of T lymphocytes, neutrophils, histiocytes and mast cells

Mucosal biopsy criteria has limited validity in terms of discrimination between ulcerative colitis (UC) and Crohn's disease (CD). The aim of this study was to set up quantitative immunohistochemical criteria, with a special focus on inflammatory cell distribution within individual specimens and throughout the large bowel. Quantitative evaluation was performed for the density of CD8+, CD45RO+, neutrophil elastase+, CD68+ and mast cell tryptase+ cells in affected and unaffected mucosa taken from 41 patients with UC and 61 patients with CD. Each slide was examined at the highest and lowest density fields, which were further divided into the upper and deeper half of mucosa. Multiple logistic regression analysis using 51 features as independent variables constructed a predictive equation finding the probability of UC (PUC), and the diagnostic categories were subsequently defined based on a receiver-operating characteristic curve. The analysis disclosed five significant features suggesting UC; these implied intense infiltration of CD8+ and mast cell tryptase+ cells, diffuse infiltration of neutrophil elastase+ and CD68+ cells, and continuous infiltration of CD45RO+ cells. The criteria consisted of three diagnostic categories, 'suggestive of UC (PUC > or = 0.7)', 'indeterminate (0.3 < PUC < 0.7)', and 'suggestive of CD (PUC < or = 0.3)'; the criteria had values for sensitivity and specificity exceeding 95%. The immunohistochemical criteria distinguishing UC from CD may help to confirm the diagnosis in patients with ambiguous endoscopic and histological diagnosis.

Distal proctocolitis and n-3 polyunsaturated fatty acids (n-3 PUFAs): the mucosal effect in situ

It has been postulated that patients with ulcerative colitis (UC) have altered reactivity of gut-associated lymphoid tissue. In such cases there is intense infiltration of the mucosa with immune competent cells and associated tissue damage. We have shown previously that the dietary supplementation with the n-3 polyunsaturated fatty acids (n-3 PUFAs), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) results in significant systemic immune suppression. The aim of this study, therefore, was to evaluate the in situ effect of n-3 PUFAs on distal proctocolitis. Each patient received either fish oil extract (EPA 3.2 g, DHA 2.4 g) (n = 9) or sunflower oil (n = 9) daily in a double blind manner for six months. Monthly assessment included: (1) disease activity using clinical, sigmoidoscopic, and histological scores and (2) immunohistochemical analysis (immunoglobulins, CD profiles) of rectal biopsy specimens (before and after six months supplementation) using monoclonal antibodies and quantitative computer-assisted video image analysis. Prior to receiving supplementation, patients with proctocolitis (n = 18) showed significantly higher numbers of cells expressing CD3 (pan T cells) and HLA-DR and IgM containing cells compared with non-colitic controls (n = 8). Six months supplementation with n-3 PUFAs resulted in significant reduction in the number of cells expressing CD3 and HLA and the percentage of cells containing IgM. There was no significant change in the CD20 nor the percentage of IgG or IgA containing cells in either group of patients with procto-colitis. In patients receiving n-3 PUFA supplementation, there was improvement in the disease activity and histological scores, compared with pretreatment evaluation. This study has demonstrated both evidence of suppression of in situ immune reactivity and concurrent reduction in disease activity in patients with proctocolitis receiving n-3 PUFA supplementation. This may have important implication for therapy in patients with ulcerative colitis.