Significance of eosinophil and mast cell counts in rectal mucosa in ulcerative colitis. A prospective controlled study

Standardized Quantification of Mast Cells in the Gastrointestinal Tract in Adults

BACKGROUND

Current data on the normal quantity of mast cells throughout the adult gastrointestinal tract are limited in several domains. These include microanatomic localization of mast cells, standardization of staining and counting methods, and reporting of microscope field of view.

OBJECTIVE

To address this lack of reliable reference ranges to facilitate the study of and diagnosis of emerging mast cell-mediated diseases.

METHODS

We examined biopsies obtained from the esophagus, stomach, duodenum, and colon from an unselected cohort. Mean and peak mast cell density were determined on slides stained for tryptase and CD117, and were expressed per high power field (hpf) and surface area (mm2), thus deriving reference ranges (average ± 2 SDs).

RESULTS

For the most common hpf surface area (0.238 mm2), upper limits of the derived reference ranges for average/peak mast cells were 0.15/3.67 (esophagus, tryptase), 0.70/5.98 (esophagus, CD117), 22.56/35.30 (stomach, tryptase), 31.32/53.10 (stomach, CD117), 30.28/49.77 (duodenal crypts, tryptase), 41.96/65.26 (duodenal crypts, CD117), 4.98/11.56 (duodenal villi, tryptase), 8.38/14.17 (duodenal villi, CD117), 26.58/41.08 (colon, tryptase), and 35.57/57.92 (colon, CD117). Interobserver variability was moderate to good. There was significant correlation between average and peak mast cell counts.

CONCLUSIONS

These data help standardize mast cell reference ranges throughout the gastrointestinal tract in adults, which can be used to determine whether abnormal levels of mast cells are present in patients with suspected mast cell-mediated disease. Our data show that the commonly used cutoff of 20 mast cells per hpf irrespective of the gastrointestinal tract segment is an underestimate of an appropriate cutoff in stomach, duodenum (crypt area), and colon.

Prognostic Value of Colonic Tissue and Blood Eosinophils in Ulcerative Colitis

BACKGROUND

It has been suggested that eosinophils may be a prognostic marker of disease outcome in ulcerative colitis (UC), but conflicting data exist. The objective was to investigate the extent of mucosal eosinophils and peripheral blood eosinophil count in newly diagnosed UC patients and to investigate its predictive value in short- and long-term disease outcomes.

METHODS

The degree of eosinophilia in baseline colonic biopsies and blood of newly diagnosed UC patients was retrospectively analyzed. It was investigated if tissue and blood eosinophilia could be a marker of a severe phenotype of UC, defined as the need for corticosteroids or immunomodulators in the first year or treatment with therapeutic monoclonal antibodies or colectomy during follow-up. Time to therapeutic monoclonal antibodies and time to colectomy were also evaluated as outcomes.

RESULTS

There were 103 UC patients (median age 26 years) included. Median tissue peak eosinophil count (PEC) was 70.0 and median peripheral blood eosinophil count was 0.3 × 109/L at diagnosis. Tissue PEC (r = -0.161, P = .104) and blood eosinophil count (r = 0.022, P = .877) were not correlated with the severity of histologic inflammation. Logistic regression analyses did not identify PEC and blood eosinophil count as predictors of more severe disease outcomes. Tissue PEC and peripheral blood eosinophil count did not predict the time the initiation of therapeutic monoclonal antibodies or colectomy.

CONCLUSION

Baseline tissue or peripheral blood eosinophils are not markers of disease activity and cannot be used as a predictor of severe disease outcomes in both adults and children with UC.

The Clinical Significance of Eosinophils in Ulcerative Colitis: A Systematic Review

BACKGROUND AND AIMS

Ulcerative colitis [UC] is characterised by an unpredictable disease course and variable response to therapy. Recent studies suggest a role for eosinophils in both pathogenesis and predicting treatment response. The goal of this study was to determine the association between eosinophils and clinical outcomes in UC.

METHODS

A systematic review of the literature from database inception to May 2021 was performed to identify all studies evaluating the relationship between eosinophils and/or eosinophil-derived proteins [EDPs] and clinical outcomes, such as disease activity, clinical relapse, severity of disease, and response to treatment.

RESULTS

A total of 55 studies were identified. Of these, 34 studies evaluated the relationship between eosinophils in colonic tissue and outcomes and 15 in blood. Eighteen studies assessed the relationship between EDPs and outcomes. In 25 of 34 studies, a positive correlation between eosinophils and/or EDPs and disease activity was reported, three studies found a negative correlation, and nine studies found no correlation. Positive correlations between eosinophils and clinical relapse were shown in four of nine studies, and with disease outcome severity in five of seven studies. Four of 15 studies showed that subjects with higher eosinophil levels had a poor response to treatment.

CONCLUSIONS

These findings suggest that higher eosinophil levels may be associated with increased disease activity and poorer clinical outcomes and response to therapy. Future studies are needed to determine whether a distinct eosinophil-rich UC phenotype exists and whether eosinophil-targeted therapy can alter the disease course.

Utilizing Deep Learning to Analyze Whole Slide Images of Colonic Biopsies for Associations Between Eosinophil Density and Clinicopathologic Features in Active Ulcerative Colitis

BACKGROUND

Eosinophils have been implicated in the pathogenesis of ulcerative colitis and have been associated with disease course and therapeutic response. However, associations between eosinophil density, histologic activity, and clinical features have not been rigorously studied.

METHODS

A deep learning algorithm was trained to identify eosinophils in colonic biopsies and validated against pathologists' interpretations. The algorithm was applied to sigmoid colon biopsies from a cross-sectional cohort of 88 ulcerative colitis patients with histologically active disease as measured by the Geboes score and Robarts histopathology index (RHI). Associations between eosinophil density, histologic activity, and clinical features were determined.

RESULTS

The eosinophil deep learning algorithm demonstrated almost perfect agreement with manual eosinophil counts determined by 4 pathologists (interclass correlation coefficients: 0.805-0.917). Eosinophil density varied widely across patients (median 113.5 cells per mm2, interquartile range 108.9). There was no association between eosinophil density and RHI (P = 0.5). Significant differences in eosinophil density were seen between patients with Montreal E3 vs E2 disease (146.2 cells per mm2 vs 88.2 cells per mm2, P = 0.005). Patients on corticosteroids had significantly lower eosinophil density (62.9 cells per mm2 vs 124.1 cells per mm2, P = 0.006). No association between eosinophil density and biologic use was observed (P = 0.5).

CONCLUSIONS

We developed a deep learning algorithm to quantify eosinophils in colonic biopsies. Eosinophil density did not correlate with histologic activity but did correlate with disease extent and corticosteroid use. Future studies applying this algorithm in larger cohorts with longitudinal follow-up are needed to further elucidate the role of eosinophils in ulcerative colitis.

Developing a standardized approach for assessing mast cells and eosinophils on tissue biopsies: A Work Group Report of the AAAAI Allergic Skin Diseases Committee

Mast cells and eosinophils are commonly found, expectedly or unexpectedly, in human tissue biopsies. Although the clinical significance of their presence, absence, quantity, and quality continues to be investigated in homeostasis and disease, there are currently gaps in knowledge related to what constitutes quantitatively relevant increases in mast cell and eosinophil number in tissue specimens for several clinical conditions. Diagnostically relevant thresholds of mast cell and eosinophil numbers have been proposed and generally accepted by the medical community for a few conditions, such as systemic mastocytosis and eosinophilic esophagitis. However, for other mast cell- and eosinophil-associated disorders, broad discrepancies remain regarding diagnostic thresholds and how samples are processed, routinely and/or specially stained, and interpreted and/or reported by pathologists. These discrepancies can obfuscate or delay a patient's correct diagnosis. Therefore, a work group was assembled to review the literature and develop a standardized consensus for assessing the presence of mast cells and eosinophils for a spectrum of clinical conditions, including systemic mastocytosis and cutaneous mastocytosis, mast cell activation syndrome, eosinophilic esophagitis, eosinophilic gastritis/enteritis, and hypereosinophilia/hypereosinophilic syndrome. The intent of this work group is to build a consensus among pathology, allergy, dermatology, hematology/oncology, and gastroenterology stakeholders for qualitatively and quantitatively assessing mast cells and eosinophils in skin, gastrointestinal, and bone marrow pathologic specimens for the benefit of clinical practice and patients.

Quantitative Analysis of Intramucosal Mast Cells in Irritable Bowel Syndrome: A Comparison With Inflammatory Bowel Disease in Remission

GOAL

We aimed to study the density of intramucosal mast cells in histologically normal colonic mucosa biopsied from patients with a clinical diagnosis of irritable bowel syndrome (IBS).

BACKGROUND

Mast cell activation has been thought to implicate in the pathogenesis of inflammatory bowel disease (IBD). Whether it serves a role in the pathogenesis of IBS remains controversial.

STUDY

A total of 127 colonoscopic mucosal biopsies were immunohistochemically stained, including 51 IBS, 66 IBD, and 10 normal control samples. Intact mast cells were quantified in 3 high power fields (HPF) in areas showing the highest density.

RESULTS

CD117 was sensitive in detecting mast cells in colonic mucosa. The mast cell counts in all biopsies ranged from 2 to 60 per HPF (mean=17.5±7.2). The density of intramucosal mast cells were similar among IBS, IBD and normal control groups (P=0.6733). IBD in remission versus IBS (17.1±8.0 vs. 18.1±7.0; P=0.4804), Crohn disease versus ulcerative colitis (17.1±10.4 vs. 17.2±5.2; P=0.9463), IBS with diarrhea versus without diarrhea (19.5±6.3 vs. 16.8±6.9; P=0.1404). Forty biopsies (31.5%) showing ≥20 mast cells per HPF appeared to equally distribute among various disease groups (P=0.7283).

CONCLUSIONS

There is no significant difference in the number of intramucosal mast cells between IBS and IBD that show normal colonic biopsies. In IBS patients, the number of intramucosal mast cell does not correlate with symptoms. The mast cell count (≥20/HPF) is not a reliable criterion for the diagnosis of IBS or for the distinction between patients with IBS and those with IBD in remission.

Eosinophilic Esophagitis Clinical Manifestations and Differential Diagnosis

As a chronic inflammatory disease with eosinophilic infiltrate of the esophagus, eosinophilic esophagitis (EoE) causes a variety of gastrointestinal (GI) clinical manifestations. None of the symptoms, endoscopic features, or biopsy findings is pathognomonic of the disease, even with high degrees of esophageal eosinophilia. The pathogenesis has been explored by several studies, yet it still far from being completely understood. Evidence supports a role of allergen-driven Th2 lymphocyte mechanism, though not in every patient. This article addresses the disease's clinical manifestations, endoscopic findings, diagnosis, and differential diagnoses. In addition to the current diagnostic criteria, we summarize some recently emerging procedures that promise of enhancing more precise diagnosis and institution of early appropriate management, with consequent better quality of life and reduction of complications.

Tissue and peripheral eosinophilia as predictors for disease outcome in children with ulcerative colitis

BACKGROUND

Eosinophils are implicated in the pathogenesis of ulcerative colitis.

AIMS

To evaluate the magnitude of mucosal and blood eosinophils in newly diagnosed pediatric ulcerative colitis patients and its significance in predicting disease outcomes.

METHODS

We retrospectively evaluated colorectal biopsies of 96 pediatric patients with ulcerative colitis and 50 age- and sex-matched controls. Samples were taken from diseased areas of the colon and examined by a gastrointestinal pathologist. The most inflamed site was used for assessment of mucosal eosinophils.

RESULTS

Samples from 96 diagnostic and 70 follow-up colonoscopies were evaluated. Median age was 13.3 years (IQR 10.1-15.3). Median duration of follow-up was 12.8 years (IQR 7.2-17.1). Median number of tissue eosinophils at diagnosis was 45 (IQR 22-73) compared to 10 eosinophils (IQR 8-25) during histologic remission (p<0.0001). Peripheral absolute eosinophil counts correlated with tissue inflammation and eosinophilia (p=0.001). Mucosal eosinophilic infiltration (p=0.02) and peripheral eosinophilia (p=0.04) was associated with clinical severity at diagnosis. Multivariate analysis showed that severe eosinophilic infiltration is associated with corticosteroid therapy following diagnosis (p=0.04) but not with long-term risk for step-up therapy or colectomy.

CONCLUSION

Tissue and peripheral eosinophilia correlate with ulcerative colitis severity at diagnosis and with short-term corticosteroid requirement but not with long-term outcomes.

Food Protein-Induced Non-Immunoglobulin E-Mediated Allergic Colitis in Infants and Older Children: What Cytokines Are Involved?

BACKGROUND

Food protein-induced allergic proctocolitis (FPIAP) is mostly a non-immunoglobulin E-mediated disease where a T-cell-mediated reaction to cow's milk protein has been suggested. We determined the expression of transforming growth factor (TGF)-β, TGF-β receptor-1, tumor necrosis factor (TNF)-α, CD86, and CD23 on the colon mucosa to investigate their roles in the pathogenesis of the two subtypes of FPIAP, i.e. infantile FPIAP and FPIAP in older children.

METHODS

Group 1 comprised children with infantile FPIAP (age <6 months, n = 21), group 2 referred to FPIAP in older children (age >1.5 years, n = 7), and group 3 included children with juvenile hyperplastic polyps (n = 22). Immunohistochemical staining of colonic biopsy specimens was performed.

RESULTS

The expression of TNF-α was significantly higher in groups 1 and 2 compared to group 3. Group 2 patients had a significantly lower TGF-β expression compared to the other groups. The expression of CD86 was higher in group 1 than in group 3 (p = 0.012). Eosinophil counts per high-power field in the lamina propria were significantly correlated with CD86 expression (p = 0.026, r = 0.388).

CONCLUSION

Our results suggest that TNF-α is implicated in the pathogenesis of both types of FPIAP. The decreased activity of TGF-β receptor-1 accompanied by the increased expression of CD86 in infants and the decreased activity of TGF-β in older children appear to play a role in the development of FPIAP.

Disease associations in eosinophilic oesophagitis and oesophageal eosinophilia

Eosinophilic infiltration into oesophageal tissue, typical of eosinophilic oesophagitis (EoE), has been described in several other conditions, including infections, hypersensitivity, and other autoimmune disorders. Since its description, EoE has been associated with an increasing number of diseases also characterized by tissue infiltration, including eosinophilic gastroenteritis and Crohn's disease. While an association between EoE and coeliac disease was previously reported, it is not supported by recent research. In contrast, EoE seems to be common in patients with a history of congenital oesophageal atresia, leading to hypotheses linking both disorders. The prevalence of EoE has also been shown to be eight times higher in patients with connective tissue disorders (CTDs), which has led to the proposal of an EoE-CTD phenotype, although this requires further assessment. This paper reviews the evidence of EoE's associations with several disorders, defining the common bases from an epidemiological, clinical, molecular and genetic perspective whenever possible.

Severe eosinophilic infiltration in colonic biopsies predicts patients with ulcerative colitis not responding to medical therapy

AIM

Eosinophils are potent proinflammatory cells that are involved in the pathogenesis of ulcerative colitis (UC). We evaluated the infiltration of eosinophils into the lamina propria in patients with active and inactive ulcerative colitis (UC) and investigated its clinical significance, among other variables, in predicting the outcome of medical treatment in active disease.

METHOD

We studied colorectal biopsy specimens from 18 UC patients with disease in long-standing remission, from 22 patients with active disease who responded to therapy (12 with complete response and 10 with partial response) and from 10 patients who were nonresponders. Demographic information was obtained at baseline, and clinical, endoscopic and laboratory data were obtained at baseline and 12 weeks post-treatment. We evaluated five histological features: mucosal ulceration; mucosal erosions; crypt abscesses; cryptitis; and eosinophilic infiltration of the lamina propria. The severity of these lesions was graded as: none or minimal; mild; moderate; or severe. Statistical analyses were performed between responders and nonresponders for differences in demographic, clinical, laboratory, endoscopic and histological parameters.

RESULTS

Laboratory, endoscopic and histological parameters were significantly improved after treatment only in the complete responders group. Analyses of baseline data revealed no significant differences in parameters between complete or partial responders and nonresponders, except for a less severe eosinophilic infiltration of lamina propria in complete responders (P < 0.05). Multiple logistic regression analysis showed that severe eosinophilic infiltration in colonic biopsies was the most significant predictor of poor response to medical therapy.

CONCLUSION

Assessing the severity of eosinophilic infiltration in the lamina propria of colonic biopsies in patients with ulcerative colitis could be a valuable predictive tool of response to medical therapy.

Soluble CD14 is essential for lipopolysaccharide-dependent activation of human intestinal mast cells from macroscopically normal as well as Crohn's disease tissue

Mast cells are now considered sentinels in immunity. Given their location underneath the gastrointestinal barrier, mast cells are entrusted with the task of tolerating commensal microorganisms and eliminating potential pathogens in the gut microbiota. The aim of our study was to analyse the responsiveness of mast cells isolated from macroscopically normal and Crohn's disease-affected intestine to lipopolysaccharide (LPS). To determine the LPS-mediated signalling, human intestinal mast cells were treated with LPS alone or in combination with soluble CD14 due to their lack of surface CD14 expression. LPS alone failed to stimulate cytokine expression in human intestinal mast cells from both macroscopically normal and Crohn's disease tissue. Upon administration of LPS and soluble CD14, there was a dose- and time-dependent induction of cytokine and chemokine expression. Moreover, CXCL8 and interleukin-1β protein expression was induced in response to activation with LPS plus soluble CD14. Expression of cytokines and chemokines was at similar levels in mast cells from macroscopically normal and Crohn's disease-affected intestine after LPS/soluble CD14 treatment. In conclusion, human intestinal mast cells appear to tolerate LPS per se. The LPS-mediated activation in mast cells may be provoked by soluble CD14 distributed by other LPS-triggered cells at the gastrointestinal barrier.

CD14+CD33+ myeloid cell-CCL11-eosinophil signature in ulcerative colitis

This study tested the hypothesis that eotaxins (CCL11, CCL24, and CCL26) and IL-5 contribute to eosinophil recruitment to the intestine in UC and that intestinal macrophages are important producers of CCL11 in this disease. Peripheral blood and rectal biopsy samples were obtained from patients with active (n=18) and quiescent UC (n=9), and control patients (n=7). Eosinophil and macrophage levels and activation were analyzed by flow cytometry. Rectal mRNA levels of CCL11, CCL24, CCL26, and IL-5 were determined by qRT-PCR. The cellular source of CCL11 was visualized by immunofluorescence analyses. Eosinophil numbers were elevated in the blood and rectum of active and quiescent UC patients compared with controls. Levels of activated eosinophils (CD66b(high)) correlated with disease severity. Rectal CCL11, CCL24, and CCL26 mRNA levels were increased in active UC, whereas only CCL11 was elevated in quiescent UC. Levels of CCL11, but not CCL24 and CCL26, positively correlated with eosinophil numbers. Numbers of CD14(+)CD33(+) cells correlated with CCL11 and eosinophil levels. Immunofluorescence analyses revealed the presence of CD14(+)CCL11(+) mononuclear cells in colonic biopsies in UC. These results support the hypothesis that CCL11 contributes to eosinophil recruitment in UC and that intestinal myeloid cells are a source of CCL11. Interestingly, rectal levels of CCL24, CCL26, and IL-5 only increase during active UC, coinciding with further elevation of eosinophil numbers and with the activation of rectal eosinophils. In conclusion, there is a link among CD14(+)CD33(+) myeloid cells, CCL11, and eosinophils in adult UC.

Eosinophils in infection and intestinal immunity

PURPOSE OF REVIEW

Inflammatory bowel diseases (IBDs, e.g., Crohn's disease and ulcerative colitis) are thought to be a consequence of an uncontrolled inflammatory response against luminal antigens, including commensal bacteria. The observed link between eosinophil levels and severity and remission rates in IBD has led to speculation that eosinophils may contribute to the antimicrobial inflammatory response in IBD.

RECENT FINDINGS

Eosinophils express the necessary cellular machinery (innate immune receptors, proinflammatory cytokines, antibacterial proteins, and DNA traps) to mount an efficient antibacterial response; however, the rapid decline in eosinophil numbers following acute systemic bacterial infection suggests a very limited role for eosinophils in bacterial responses.

SUMMARY

We describe the clinical evidence of eosinophil involvement in IBD, summarize the in-vitro and in-vivo evidence of eosinophil antibacterial activity and the biology of eosinophils focusing on eosinophil-mediated bactericidal mechanisms and the involvement of eosinophil-derived granule proteins in this response, and conceptualize the contribution of eosinophils to a response against commensal bacteria in IBD.

Innate immunity modulation by the IL-33/ST2 system in intestinal mucosa

Innate immunity prevents pathogens from entering and spreading within the body. This function is especially important in the gastrointestinal tract and skin, as these organs have a large surface contact area with the outside environment. In the intestine, luminal commensal bacteria are necessary for adequate food digestion and play a crucial role in tolerance to benign antigens. Immune system damage can create an intestinal inflammatory response, leading to chronic disease including inflammatory bowel diseases (IBD). Ulcerative colitis (UC) is an IBD of unknown etiology with increasing worldwide prevalence. In the intestinal mucosa of UC patients, there is an imbalance in the IL-33/ST2 axis, an important modulator of the innate immune response. This paper reviews the role of the IL-33/ST2 system in innate immunity of the intestinal mucosa and its importance in inflammatory bowel diseases, especially ulcerative colitis.

Cells, cytokines and inflammatory bowel disease: a clinical perspective

Ulcerative colitis and Crohn's disease are chronic inflammatory disorders of the GI tract. Although the disorders can usually be distinguished on clinical and pathological criteria, there are similarities in natural history and response to therapy. The purpose of this article is to examine the inflammatory infiltrate in both disorders and the cytokine profiles in intestinal mucosa and peripheral blood. For both disorders, the predominant cells in inflamed mucosa are neutrophils and lymphocytes positive for CD4. There are also increases in the number of B cells, macrophages, dendritic cells, plasma cells, eosinophils and perhaps mast cells. Cytokine levels and cytokine expression are also similar for both disorders, with increases in TNF-α and IFN-γ consistent with a Th1 response. As inflammation occurs in a microbial environment, one possibility is that the nature of the inflammatory response is largely independent of initiating factors. One concept that might be useful is that of initiating cells and cytokines and effector cells and cytokines. Persuasive evidence exists for a defect in phagocytic cells in Crohn's disease, perhaps with the expansion of a subset of activated macrophages. There are also possible links to natural killer cells and changes in the regulation of IL-8 and perhaps IL-22. For ulcerative colitis, the cellular events are less clear, but natural killer T cells may be important as initiating cells, and there is some evidence for upregulation of cytokines involved in Th2 responses, including IL-4 and IL-13. For both disorders, proinflammatory cytokines include TNF-α, IL-12, IL-23, and perhaps IL-17 and IFN-γ. Research challenges include the identification, activation and function of subsets of inflammatory cells, as well as new ways to terminate the inflammatory response.

Eosinophilic diseases of the gastrointestinal tract

Eosinophilic gastrointestinal disorders (EGIDs) are a diverse group of disorders whose diagnosis is on the rise and are characterized by symptoms caused by infiltration by eosinophils of the different sections of the digestive tract. Although little is known of their etiology, it seems to be multifactorial. Alteration of the immunological capacity of the digestive mucosa is determined by the exposure of genetically predisposed individuals to potential airborne or food allergens. EGIDs are classified based on the location of the inflammatory response even though their symptoms, prognosis, and treatment vary considerably. Eosinophilic esophagitis is the most widely recognized entity in this family and is characterized by exclusive eosinophilic infiltration of the esophagus. Breakthroughs in understanding its etiopathogeny have been extrapolated to eosinophilic gastroenteritis, a rare disease identified many years ago commonly involving the stomach and small bowel which should be distinguished from hypereosinophilic syndrome. Eosinophilic colitis, which usually affects children, could be considered a specific non-IgE-mediated allergy to food protein. The physiopathological bases of these entities need to be established in order to define specific treatment aimed at preventing and altering their clinical evolution.

Gastrointestinal eosinophils in health, disease and functional disorders

Eosinophils are potent innate immune cells that home to the gastrointestinal tract where they participate in host immunity to luminal pathogens, and help to maintain intestinal epithelial homeostasis. However, these cells are now recognized to have key functions in the pathogenesis of numerous other disorders of the gastrointestinal tract, including primary eosinophilic gastrointestinal disease, common functional conditions, such as dyspepsia, and also in gastrointestinal disorders in patients with allergic disease. We are just beginning to understand the potential pathological role of eosinophils in gastrointestinal disease, and it is increasingly likely that gastroenterologists and histopathologists will need to account for the presence of gastrointestinal eosinophils and relate their presence to gastrointestinal symptoms. This Review discusses the role of gastrointestinal eosinophils in health and disease, including their associations with functional and allergic disorders.

Induced sputum eosinophilia in ulcerative colitis patients: the lung as a mirror image of intestine?

BACKGROUND

Ulcerative colitis (UC) is a systemic disease of unknown etiology with extra-intestinal manifestation. Induced sputum (IS) non-invasively assesses extrapulmonary involvement in Crohn's disease. We sought to determine whether there is a cellular marker of lung injury in UC patients detectable by IS.

METHODS

Nineteen UC patients (mean age 46.4+/-11.3 years, disease duration 8.6+/-7.5 years [range 1-25 years] 68.4% males) were studied, 6 with active disease and 13 in remission. Eleven received 5-ASA, 5 received steroids and/or azathioprine and 3 patients were untreated. UC patients were compared with 27 healthy non-smoker controls. IS was recovered after 20 min inhalation of 3% saline with an ultrasonic nebulizer by the selecting plugs method, and 300 cells were differentially cell counted in cytospin Giemsa-stained slides. CD4/CD8 subsets were identified by FACS. Pulmonary function tests were performed by the Jaeger Masterlab spirometer.

RESULTS

UC patients' IS contained higher %eosinophils than controls (p=0.05) and lower FEV(1)/FVC ratios (p=0.001). Steroid- and/or azathioprine-treated patients had significantly lower FEV(1)/FVC ratios than only 5-ASA-treated patients (p=0.019). Eosinophil infiltration in airways was high in 5-ASA-treated patients compared to those receiving steroids and/or azathioprine (p=0.046) and those with less extensive disease (p=0.05). Using a cutoff of 3% eosinophils, IS had a sensitivity of 67% and specificity of 73% to differentiate patients with a cutoff of 70 eosinophils/mm(2) in biopsy.

CONCLUSIONS

The percentage of sputum eosinophils is significantly different between UC patients with proctitis and pancolitis. These immune abnormalities may be a common pattern that is present throughout the mucosae.

Evaluation of tissue eosinophilia in the pouch and afferent limb in patients with restorative proctocolectomy

BACKGROUND

Although tissue eosinophilia in mucosal biopsy specimens from the ileal pouch in patients treated with restorative proctocolectomy is frequently seen, its clinical significance has not been investigated. The aim of this study was to assess whether tissue eosinophilia was associated with disease status of ileal pouches.

METHODS

Hematoxylin and eosin slides of pouch and afferent limb biopsy specimens from 106 patients randomly selected from the Pouchitis Database were evaluated by 2 gastrointestinal pathologists. Of 106 patients, 81 had corresponding mucosal biopsy specimens of the afferent limb that were available for review. Tissue eosinophil infiltration was evaluated in a semiquantitative fashion with scores ranging from 0-3. Univariate and multivariate analyses were performed to assess the association between eosinophil scores and demographic, clinical, endoscopic, and histologic features.

RESULTS

Multivariate analyses showed that tissue eosinophilia of the pouch and afferent limb was not associated with chronic inflammatory conditions of the pouch and the presence of concurrent autoimmune-mediated disorders. Tissue eosinophil score of the pouch was significantly higher than that in the corresponding afferent limb in the same patient population (P = 0.043). A high tissue eosinophil score in the afferent limb was associated with non-use nonsteroidal antiinflammatory drug use (odds ratio = 3.5; 95% confidence interval [CI]: 1.2, 10.4) and high endoscopic inflammation scores in the afferent limb (odds ratio = 1.6; 95% CI: 1.1, 2.2). Similar associations were not found in pouch biopsy specimens.

CONCLUSIONS

Tissue eosinophilia in the pouch was more prominent than that in the afferent limb in patients with restorative proctocolectomy. Tissue eosinophilia in the pouch and afferent limb appeared to be associated with different risk factors. These findings suggest that luminal factors in different topographical locations of the pouch may contribute to eosinophil-mediated inflammation at these sites.

Role of gastrointestinal eosinophils in inflammatory bowel disease and intestinal tumours

Eosinophils have been implicated in the pathogenesis of inflammatory bowel disease (IBD). Immunohistopathological studies have revealed accumulation and activation of eosinophils in actively inflamed intestinal mucosa of Crohn's disease and ulcerative colitis patients. Elevated levels of chemokines relevant for eosinophil chemotaxis and mediator release from eosinophils can be detected in serum and faeces of patients with active IBD. Animal studies have revealed that abrogation of chemokines (such as eotaxin) promoting eosinophil chemotaxis and circulation results in decreased severity of murine experimental colitis, suggesting a pro-inflammatory role for eosinophils in IBD. Furthermore, selective deletion of certain eosinophil-specific granule products results in attenuation of experimental intestinal inflammation. Shortly after their initial discovery by Ehrlich, eosinophils have been associated with intestinal tumours. However, as only very few studies have addressed the role of eosinophils in intestinal cancerogenesis, their impact on intestinal tumour development remains obscure; in particular, functional data are missing.

Eosinophils: biological properties and role in health and disease

Eosinophils are pleiotropic multifunctional leukocytes involved in initiation and propagation of diverse inflammatory responses, as well as modulators of innate and adaptive immunity. In this review, the biology of eosinophils is summarized, focusing on transcriptional regulation of eosinophil differentiation, characterization of the growing properties of eosinophil granule proteins, surface proteins and pleiotropic mediators, and molecular mechanisms of eosinophil degranulation. New views on the role of eosinophils in homeostatic function are examined, including developmental biology and innate and adaptive immunity (as well as their interaction with mast cells and T cells) and their proposed role in disease processes including infections, asthma, and gastrointestinal disorders. Finally, strategies for targeted therapeutic intervention in eosinophil-mediated mucosal diseases are conceptualized.

Fecal levels of leukocyte markers reflect disease activity in patients with ulcerative colitis

OBJECTIVE

A prominent feature of inflammatory bowel disease (IBD) is the presence of inflammatory cells in the gut mucosa, and which contribute to the ongoing inflammatory process. The aim of the study was to evaluate fecal neutrophil, eosinophil, mast cell and macrophage markers in the assessment of disease activity in patients with ulcerative colitis (UC).

METHODS

Twenty-eight patients with active UC; 4 with proctitis, 16 with left-side colitis and 8 with total colitis, were included in the study. Patient history, endoscopy and histopathology were examined and fecal and serum samples were evaluated at inclusion and after 4 and 8 weeks of treatment. Fecal samples were analysed for myeloperoxidase (MPO), eosinophil protein X (EPX), mast cell tryptase, IL-1beta and TNF-alpha using immunoassays. Blood samples were analysed for MPO, EPX, C-reactive protein, orosomucoid and leucocyte counts.

RESULTS

Fecal MPO and IL-1beta levels were elevated in all patients at inclusion despite different disease extensions. Striking reductions in fecal levels of MPO, EPX, tryptase and IL-1beta were observed after 4 weeks of treatment in 20/28 patients with complete remission after 8 weeks. No further reductions were seen in 20/27 patients at 8 weeks. Endoscopic score correlated to IL-1beta at all visits (p<0.01), to MPO at visits 2 and 3 (p<0.05, p<0.001), EPX at visit 2 (p<0.05) and tryptase at visit 3 (p<0.01). Levels of fecal markers also related to histological indices of the disease.

CONCLUSIONS

Measurements of fecal MPO, EPX and IL-1beta could be objective complements to endoscopical and histopathological evaluations in the daily care of patients with UC.

Mucosal mast cells are pivotal elements in inflammatory bowel disease that connect the dots: Stress, intestinal hyperpermeability and inflammation

Mast cells (MC) are pivotal elements in several physiological and immunological functions of the gastro-intestinal (GI) tract. MC translate the stress signals that has been transmitted through brain gut axis into release of proinflammatory mediators that can cause stimulation of nerve endings that could affect afferent nerve terminals and change their perception, affect intestinal motility, increase intestinal hyperpermeability and, in susceptible individuals, modulate the inflammation. Thus, it is not surprising that MC are an important element in the pathogenesis of inflammatory bowel disease and non inflammatory GI disorders such as IBS and mast cell enterocolitis.

Antibody to eosinophil cationic protein suppresses dextran sulfate sodium-induced colitis in rats

AIM: To produce an antibody against rat eosinophil cationic protein (ECP) and to examine the effects of the antibody in rats with dextran sulfate sodium (DSS)-induced colitis.

METHODS: An antibody was raised against rat ECP. Rats were treated with 3% DSS in drinking water for 7 d and received the antibody or normal serum. The colons were examined histologically and correlated with clinical symptoms. Immunohistochemistry and Western blot analysis were estimated as a grade of inflammation.

RESULTS: The ECP antibody stained the activated eosinophils around the injured crypts in the colonic mucosa. Antibody treatment reduced the severity of colonic ulceration and acute clinical symptoms (diarrhea and/or blood-stained stool). Body weight gain was significantly greater and the colon length was significantly longer in anti-ECP-treated rats than in normal serum-treated rats. Expression of ECP in activated eosinophils was associated with the presence of erosions and inflammation. The number of Ki-67-positive cells in the regenerated surface epithelium increased in anti-ECP-treated rats compared with normal serum-treated rats. Western blot analysis revealed reduced expression of macrophage migration inhibitory factor (MIF) in anti-ECP-treated rats.

CONCLUSION: Our results indicate that treatment with ECP antibody, improved DSS-induced colitis in rats, possibly by increasing the regenerative activity of the colonic epithelium and downregulation of the immune response, and suggest that anti-ECP may promote intestinal wound healing in patients with ulcerative colitis (UC).

[Eosinophilic gastroenteritis in a tropical area: report of a Congolese case]

Eosinophilic gastroenteritis is an uncommon disease with an unknown natural history, and its relation to digestive allergies has not been confirmed. This study reports the case of a 27 year old patient who developed eosinophilic gastroenteritis with gastric, intestinal, rectal and peritoneal localisations. In the Congo, massive blood hypereosinophilia suggests digestive parasitosis and gastroenteritis with malnutrition and cutaneous symptoms suggest AIDS/HIV, making the present agnosis uncommon.

Heightened responses to stressors in patients with inflammatory bowel disease

OBJECTIVES

Several studies suggest that stressful situations (stressors) worsen the course of inflammatory bowel disease (IBD), but the mechanism is not known. Based on several lines of evidence, we hypothesized that psychosocial stress activates the brain-gut axis (BGA) and mucosal mast cells (MC), and activated MC produce proinflammatory cytokines. To test this hypothesis, we determined whether stressor-induced activation of BGA is exaggerated in IBD patients.

METHODS

Stress was induced in 15 IBD patients who were in remission (inactive IBD) and in seven controls by a widely used stressor, the cold pressor test (CPT), daily for five consecutive days. Induction of stress was confirmed objectively by measurement of stress hormones (serum cortisol and ACTH), and hemodynamic parameters and subjectively by questionnaire. Activation of the BGA by this stressor was assessed by evaluating colonic mucosal MC histology and degranulation, using electron microscopy (EM). The effects of the stressor on the intestinal mucosa were assessed by changes in inflammatory cell histology, epithelial mitochondria (EM), and oxidative tissue injury (assays for protein oxidation).

RESULTS

In both study groups, the stressor resulted in (1) increased levels of stress hormones, (2) the expected changes in hemodynamic parameters, (3) activation and degranulation of MC, (4) mitochondrial damage to epithelial cells, and (5) mucosal protein oxidation. These changes were more marked in IBD patients.

CONCLUSIONS

The heightened response to the stressors and the greater epithelial damage in IBD patients suggests that stress-induced activation of the BGA and of mucosal MC is important in the initiation and/or flare up of IBD.

Evaluation of mucosal eosinophils in the pediatric colon

To evaluate the clinical significance of colonic eosinophilia, we conducted a retrospective study of all children older than 1 year evaluated at Children's Hospital of Pittsburgh from January 1999 to June 2001 with a description of colonic eosinophilia in the pathology report. Medical records were reviewed. Diagnoses were confirmed by contacting the patients. Histological slides (H&E) were reviewed by an investigator blind to the patients' data. Biopsies were grouped according to the site they were taken from and then screened at low power for areas of maximal eosinophilia for further quantitative analysis. Results of manual counts were validated by image analysis using Metaphor Image Analysis Software. Sixty-nine children with colonic eosinophilia were identified (36 male; mean age, 135.2 +/- 55.4 months). Their final diagnoses were inflammatory bowel disease in 32% (group A), irritable bowel syndrome in 33% (group B), food allergies in 10% (group C), and other diagnoses in 25% (group D). The maximal eosinophil count per crypt area was significantly (P < 0.05) higher in group A vs groups B, C, and D (34.8 +/- 17.1 vs 21.3 +/- 8.8, 25.4 +/- 16.7, and 24.2 +/- 9.7, respectively). The total cellularity of the lamina propria was considered high only in group A (P < 0.05 vs groups B and C). A mostly equal vertical distribution of eosinophils throughout the lamina propria was found significantly more frequently in group A vs groups C (P = 0.04) and D (P = 0.007). We conclude that children with inflammatory bowel disease have an equal distribution of eosinophils throughout the lamina propria, with intraepithelial and intracryptal eosinophils and with a higher overall total cellularity. In irritable bowel syndrome and patients with a variety of other diagnoses, including allergies, the distribution is mostly superficial, with a lower total cellularity.

The role of mast cells in common gastrointestinal diseases

The gastrointestinal tract is a rich source of mast cells with an enormous surface area that permits a high degree of interaction between the mast cell and the intestinal contents. The active metabolic products of the mast cell influence gastrointestinal secretion, absorption, and motility through paracrine effects of local mast cell activation and also cause systemic effects through the release of cellular products into the bloodstream. Recent advances in our knowledge of the immune system and the recognition that the gastrointestinal immune function might be partially mediated through gastrointestinal mucosal mast cells has opened mast cell research to the field of gastroenterology. Local gastrointestinal proliferation of mast cells in response to recognized or obscure stimuli can alter gastrointestinal function and induce systemic symptoms. Symptoms can arise from the increased number of mast cells, overproduction of specific mast cell mediators, and hyperactivity of the enteric nervous system that induces mast cell activation. The diseases mentioned in this review represent a small proportion of areas where mast cell function might play an important role in the response to disease and generation of symptoms.

Immunohistochemical study of intestinal eosinophils in inflammatory bowel disease

BACKGROUND

Eosinophil accumulation and activation are characteristic features of inflammation in allergic diseases and in host defense against parasites.

GOALS

To investigate the involvement of eosinophils in inflamed and noninflamed mucosa of patients with inflammatory bowel disease (IBD).

STUDY

Specimens of inflamed colonic mucosa from 15 patients with ulcerative colitis (UC) and inflamed and noninflamed colonic mucosa from 15 patients with Crohn's disease (CD) were submitted to histologic and immunohistochemical studies. Twelve patients with irritable bowel syndrome were studied as controls. Sirius red was used to label eosinophils in tissue. EG1, EG2, and anti-hIL-5 were used as primary antibodies in an indirect alkaline phosphatase-labeled immunostaining protocol. Both positive and negative lamina propria cells were assessed by a quantitative grading system and the results expressed as cell numbers per mm.

RESULTS

Increased proportions of eosinophils stained with Sirius red, EG1, EG2, and anti-hIL-5+ cells were found in the colon of patients with UC and in inflamed and noninflamed colon of CD patients as compared with controls. Crohn's disease patients showed increased proportions of EG1+ and EG2+ cells as compared with those with UC. Increased proportions of IL-5+ cells were detected in UC patients as compared with those with CD.

CONCLUSION

Quantitative eosinophil alterations and IL-5+ cells may indicate enhanced cellular activation with degranulation, which is implicated in the pathogenesis of IBD. Increase in IL-5+ cells may reflect a predominant local Th2 response in UC as compared with CD.

A new method for the quantification of neutrophil and eosinophil cationic proteins in feces: establishment of normal levels and clinical application in patients with inflammatory bowel disease

OBJECTIVES

The aims of this study were 1) to develop a valid method for the measurement of the eosinophil proteins eosinophil cationic protein (ECP) and eosinophil protein X (EPX) and neutrophil proteins myeloperoxidase and human neutrophil lipocalin (HNL) in feces and 2) to investigate their potential role as disease activity markers in inflammatory bowel disease (IBD).

METHODS

Feces samples were obtained from 44 apparently healthy individuals (HIs), 18 patients with IBD (11 with ulcerative colitis [UC] and seven with Crohn's disease [CD]), and three with collagen colitis. The granulocyte markers were measured using immunoassays in supernatants from processed feces.

RESULTS

ECP, myeloperoxidase, and, to a lesser degree, EPX and HNL were bound to the solid part of feces. However, feces homogenized in an extraction buffer containing the cationic detergent N-cetyl-N,N,N-trimethylammonium bromide allowed an efficient recovery of the proteins (i.e., up to 100-fold increased levels compared to homogenization in saline). All four proteins were stable for at least 7 days at +6 degrees C and at least 3 days at +22 degrees C. The normal fecal geometric mean (95th percentile) levels of ECP, EPX, myeloperoxidase, and HNL were estimated to be, respectively, 1.69 microg/g (6.41), 0.57 microg/g (1.72), 3.54 microg/g (8.77), and 1.97 microg/g (4.91). Markedly increased feces levels of all markers (p < 0.0002), compared to HIs and CD patients, were observed in UC. However, the marker levels in CD patients were significantly increased relative to HIs (p < 0.05 to p < 0.0002). Increased levels of HNL and myeloperoxidase were also observed in the three collagen colitis patients. The discriminative capability between UC patients and HIs was somewhat superior for EPX and myeloperoxidase.

CONCLUSIONS

The method described here takes into account the molecular properties of the granule proteins and the heterogeneity in feces consistency, which is a prerequisite for a valid and reproducible measurement of cationic granule proteins. We suggest that EPX and myeloperoxidase, when applied in IBD, are the best eosinophil and neutrophil markers for studying GI inflammation.

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.

Distribution and activation of eosinophils in inflammatory bowel disease using an improved immunohistochemical technique

Eosinophils are a recognized feature of inflammatory bowel disease (IBD), but their tissue distribution and functional importance in Crohn's disease (CD) and ulcerative colitis (UC) remain obscure. This study describes an improved immunohistochemical protocol to identify eosinophils in full thickness bowel wall specimens of IBD (n=40) and their in situ relationships with the chemoattractants eotaxin and RANTES. Eosinophils were identified using immunohistochemistry with a combination of monoclonal antibodies (EG1+EG2+MBP), an ultrasensitive technique superior to other methodologies, and their tissue distributions were related to those for eotaxin, RANTES, mast cells and neutrophils. Increased numbers of eosinophils (up to 400 cells/mm(2)) were observed in active, fulminant inflammation in both CD and UC, this being related to the severity of inflammation and not the diagnosis of the two disorders. The chemoattractants eotaxin (CCL11) and RANTES (CCL5) were upregulated in IBD tissues showing eosinophilia. Neutrophils and mast cells were commonly associated with eosinophil accumulations. Eosinophil numbers and their in situ activation are increased in active rather than chronic IBD. The observations strongly suggest a pivotal role for the eosinophil and its potent mediators in many pathophysiological symptoms of CD and UC, where it represents the major proportion of all granulocytic cells in active inflammatory bowel disease.

Increased serum levels of eotaxin in patients with inflammatory bowel disease

BACKGROUND

The CC-chemokines eotaxin and eotaxin-2, produced by epithelial and phagocytic cells, are potent and selective chemoattractants for eosinophils and basophils. The eosinophil is a potent inflammatory cell thought to play an important role in the pathogenesis of inflammatory bowel disease (IBD). In this study we investigated the serum concentrations of eotaxin and eotaxin-2 in patients with Crohn disease and ulcerative colitis.

METHODS

Thirty-one patients with Crohn disease, 35 patients with ulcerative colitis and 41 control patients were studied. Eotaxin and eotaxin-2 serum levels were measured with solid phase sandwich enzyme-linked immunosorbent assays.

RESULTS

Significantly increased serum eotaxin levels were observed in both patients with Crohn disease (289.4+/-591.5 pg/ml) and ulcerative colitis (207.0+/-243.4 pg/ml) when compared with controls (138.0+/-107.8 pg/ml) (P < 0.01). Moreover, patients with active Crohn disease and ulcerative colitis showed significantly higher serum eotaxin levels than patients with quiescent disease (434.0+/-776.8 pg/ml versus 113.8+/-65.4 pg/ml in Crohn disease and 295.7+/-337.1 versus 121.2+/-91.9 pg/ml in ulcerative colitis, P < 0.05). In contrast, there was no significant difference in eotaxin-2 serum levels among patients with Crohn disease (863.5+/-448.2 pg/ml), ulcerative colitis (1028.3+/-431.4 pg/ml) and controls (981.4+/-539.4 pg/ml).

CONCLUSIONS

Eotaxin is significantly increased in serum of patients with active Crohn disease and ulcerative colitis, suggesting that this cytokine may play a role in the pathogenesis of IBD.

Allergy and mucosal eosinophil infiltrate in ulcerative colitis

BACKGROUND

Data on allergy in ulcerative colitis (UC) have led to conflicting conclusions without proving any causal association. In this report we have investigated the presence of allergy and its possible relation with chronic colonic inflammation in patients with UC.

METHODS

Fifty UC patients underwent clinical, endoscopic, and histologic evaluations. The allergologic study included family/personal history; prick/patch exposition to airborne, food, and contact allergens; total serum IgE; and quantification of eosinophils in peripheral blood and intestinal mucosa. Diagnosis of rhinitis, conjunctivitis, and asthma was confirmed by specific provocation tests. Fifty healthy subjects were studied as control group.

RESULTS

A higher prevalence of allergic symptoms was found in patients (56%) and their first-degree relatives (52%) than in controls (18% and 26%) (P < 0.0001; P = 0.008). In patients skin tests showed increased rates of immediate (54%) and delayed-type (20%) hypersensitivity compared with controls (30% and 6%) (P= 0.01; P= 0.03). Diagnosis of allergic IgE-mediated disease was made in 19 cases and 6 controls (P= 0.01), and allergic contact dermatitis in 10 and 3, respectively (P= 0.03). IgE levels were higher in UC patients than in controls (P=0.02). No dose-response relationship was found between degree of colonic tissue eosinophilia and clinical. endoscopic, and histologic disease severity. The degree of colonic tissue eosinophilia was higher in the presence of skin reactivity to food allergens.

CONCLUSIONS

UC patients frequently show several markers of allergy. In particular, our data suggest an association between ulcerative colitis, tissue eosinophilia, and type-I allergy.

Increased concentrations of eosinophilic cationic protein in whole-gut lavage fluid from children with inflammatory bowel disease

BACKGROUND

Eosinophils may be involved in the pathogenesis of inflammation in inflammatory bowel disease. The purpose of this study was to verify whether concentrations of eosinophilic cationic protein in gut lavage fluid from children with inflammatory bowel disease correlate with clinical and laboratory indexes of disease activity.

METHODS

Twenty-three children with Crohn's disease, 14 with ulcerative colitis, and 22 age-matched control subjects entered the study. Radioimmunoassay and sandwich enzyme-linked immunosorbent assay techniques were used to measure eosinophilic cationic protein, total immunoglobulin G and interleukin-1beta, respectively.

RESULTS

Gut lavage eosinophilic cationic protein levels were significantly (p < 0.005) higher in patients with Crohn's disease and ulcerative colitis than in control subjects. Intestinal eosinophilic cationic protein levels decreased in three of four children with Crohn's disease who were fed an elemental diet. There was a significant (p < 0.001) correlation between eosinophilic cationic protein concentrations and immunoglobulin G and interleukin-1beta levels in gut lavage fluid.

CONCLUSIONS

Elevated intestinal eosinophilic cationic protein levels in inflammatory bowel disease suggest that eosinophils are involved in the gastrointestinal inflammation in this disease. Intestinal eosinophilic cationic protein concentration is another marker with which to discriminate between active and inactive inflammatory bowel disease.

A quantitative immunohistochemical evaluation of inflammatory cells at the affected and unaffected sites of inflammatory bowel disease

Levels of T lymphocytes, histiocytes and mast cells have been reported to be increased in the affected mucosa of Crohn's disease (CD) and ulcerative colitis (UC), but the colorectal distribution of these cells is not fully understood. We hypothesized that differences in cell densities between CD and UC would be characteristic, not only in the affected, but also in the unaffected mucosa. The aims of the present study were to clarify whether there were any differences in cell densities in CD, UC and infectious colitis (IC) in the affected mucosa and between CD and UC in the unaffected mucosa. Using mouse monoclonal antibodies recognizing memory T cells (OPD4), cytotoxic/suppressor T cells (C8/144B), histiocytes (PG-M1) and mast cells (AA1), we evaluated mucosal cell densities in biopsy specimens from both endoscopically affected and unaffected sites of CD (n = 12) and UC (n = 15) and from affected sites of IC (n = 10). Ten normal controls were also examined. At affected sites, all cells were significantly more abundant in UC than in the other conditions, except that the density of PG-M1+ in CD was similar to that seen in UC. Although the densities of OPD4+ and C8/144B+ cells at unaffected sites were slightly higher in both CD and UC and in UC, respectively, there was no significant difference in cell densities between CD and UC. The ratio of OPD4+ cell density at affected sites to that at unaffected sites was appreciably higher in UC than in CD. The results suggest that a common feature of UC and CD is an increase in PG-M1+ cells at the affected mucosa but that the other inflammatory cells studied are more abundant, particularly in UC, and that the difference between UC and CD is conspicuous when comparing the OPD4+ cell density of the affected mucosa with that of the unaffected mucosa.

Increased eosinophil granule proteins in gut lavage fluid from patients with inflammatory bowel disease

OBJECTIVE

To explore the potential role of eosinophils in the pathogenesis of inflammatory bowel disease (IBD).

DESIGN

We measured the concentrations of eosinophil granule proteins-namely, major basic protein, eosinophil peroxidase, eosinophil cationic protein, and eosinophil-derived neurotoxin-in gut lavage fluid.

MATERIAL AND METHODS

Ten healthy persons and 17 patients with IBD (9 with Crohn's disease and 8 with ulcerative colitis) underwent gut lavage. Each study subject submitted an early specimen when lavage effluent became liquid and a late specimen when the output became clear. The concentrations of the granule proteins were measured by immunoassay.

RESULTS

The median concentrations of eosinophil-derived neurotoxin and eosinophil cationic protein were significantly higher in patients with IBD than in control subjects for both early and late lavage specimens. Excretion of eosinophil peroxidase was also significantly higher in patients with IBD than in the healthy control subjects, but only in the early specimens. No differences were noted in the concentrations of any of the proteins between patients with ulcerative colitis and those with Crohn's disease.

CONCLUSION

Concentrations of eosinophil granule proteins were increased in whole gut lavage fluid from patients with IBD in comparison with healthy control subjects. These results encourage further studies of the role of eosinophils in the pathogenesis of IBD.

Evaluation of the role of mast cells in the progression of acetic acid-induced colitis in mice

BACKGROUND

Mast cells are widely distributed in the gastrointestinal mucosa. However, their role in the pathogenesis of inflammatory bowel disease remains unsettled. The aim of the present study is to clarify the relative importance of mast cells in the progression of acetic acid-induced colitis in mice.

METHODS

Mast cell-deficient W/Wv and their normal littermate +/+ mice were given intrarectal administration of 5% acetic acid. The severity of colonic damage, the number of mast cells, and myeloperoxidase (MPO) activities in the colonic tissues were examined.

RESULTS

The severity of colonic damage was comparable between W/Wv and +/+ mice. In both groups of animals kinetic changes of the severity of the mucosal damage agreed well with that of MPO activities in the colonic mucosa. Pretreatment with a mast cell stabilizer, ketotifen, did not affect the severity of colitis in +/+ mice.

CONCLUSIONS

These results discount, but do not disprove, the role of mast cells in the progression of acetic acid-induced colitis in mice.

Human eotaxin is a specific chemoattractant for eosinophil cells and provides a new mechanism to explain tissue eosinophilia

Eotaxin is an eosinophil-specific chemoattractant that has been recently identified in rodent models of asthma and host response against tumors. To determine whether a similar molecule might play a role in human inflammatory diseases characterized by eosinophilia, we isolated the human eotaxin gene. We demonstrate that human eotaxin is an early response gene of cytokine-stimulated epithelial and endothelial cells, and is induced in peripheral blood eosinophils by interleukin-3. Eotaxin is directly chemotactic for eosinophils, but not mononuclear cells or neutrophils. Eotaxin messenger RNA accumulates markedly in the lesions of patients with inflammatory bowel disease (ulcerative colitis and Crohn's disease), but not in the lesions of patients with diverticulitis. These results now provide a mechanism involving eotaxin to explain the eosinophil infiltration seen in a variety of human disease; as such, an eotaxin antagonist may be a novel therapy for certain human diseases characterized by tissue eosinophilia.

Lack of crucial role of mast cells in pathogenesis of experimental colitis in mice

Mast cell alterations have been implicated in the pathogenesis of chronic ulcerative colitis (UC). We studied the effect of mast cell deficiency of the severity of inflammation in a murine model of colitis. Colitis was induced in mice using dextran sodium sulfate (DSS). Mast-cell-deficient mice (WBB6F1/J-W/WV; N = 17) and normal littermates (WBB6F1/J-+/+; N = 17) were administered DSS 4% w/v for seven days, then water alone for one week, followed by 5% DSS for six days. Animals were sacrificed at the end of the protocol. Segments of proximal, mid-, and distal colon of each animal were processed for histopathological examination. Mortality and morbidity (diarrhea and weight loss) for each group were assessed. There was no significant difference between the two groups in either their clinical parameters (mortality and morbidity) or the severity of colitis as graded histopathologically. Our findings suggest that mast cells are not crucial for the development of DSS-induced colitis.

Functional and morphological changes in small bowel of Crohn's disease patients. Influence of site of disease

Morphological and functional changes were examined in the upper jejunum and terminal ileum of 18 patients suffering from Crohn's disease. Intestinal permeability, biochemical determination of enzymatic activities, and morphologic evaluation of the severity of the lesions were evaluated. Ulcerative colitis and irritable bowel syndrome patients served as controls. We found abnormal lactulose-mannitol tests in all patients with active Crohn's disease. Permeability changes correlated with increased crypt cell proliferation, as indicated by thymidine kinase activity. A significant reduction in brush border enzyme activities was seen in the terminal ileum, but no significant change was observed in the unaffected upper jejunum. The number of mast cells was increased in the diseased ileum. We conclude that the site of inflammation and the healing capacity of the epithelium are important in determining functional and biochemical abnormalities in active Crohn's disease. Changes may be dependent on the type and number of immune cells involved in the inflammatory process.

Changes of colonic vasoactive intestinal peptide and cholinergic activity in rats with chemical colitis

The vasoactive intestinal peptide concentration was examined in the colonic wall and portal venous plasma of rats with chemical colitis by radioimmunoassay, and the colonic localization was determined with immunocytochemistry. Colonic acetylcholine esterase activity was also measured, and the response of vasoactive intestinal peptide to acetylcholine administration was determined. Colitis was induced by administration of dextran sulfate for three months. The chemical colitis was histologically similar to active human ulcerative colitis. We observed a significant increase of immunostained neurons and nerve fibers and a significant rise in the colonic wall vasoactive intestinal peptide content in chemical colitis rats, while plasma concentrations of the peptide did not change significantly. Colonic acetylcholine esterase activity was significantly elevated in colitis rats compared with control rats. Systemic administration of acetylcholine significantly increased the colonic and plasma vasoactive intestinal peptide concentrations in colitis rats. These findings demonstrated a positive association between colitis activity and an increase of vasoactive intestinal peptide and suggested that increased vagal tone promoted the peptide's release.

Colonic mucosal mast cell distribution at line of demarcation of active ulcerative colitis

We examined the distribution of colonic mucosal mast cells in 25 patients with active ulcerative colitis, with a clear line of demarcation separating active inflammation from normal mucosa. Biopsies, at least one adjacent to the line of demarcation, one in inflamed mucosa, and one above were obtained during colonoscopy. Eight patients had elevated mast cells throughout the colon, and 12 had increased numbers at the line of demarcation of disease. Mean numbers of mast cells from these patients were 6.3 (+/- 2.1 SD) in active inflammation, 19.5 (+/- 7.1 SD) at the line of demarcation, and 15.8 (+/- 8.4 SD) in normal mucosa. Histologic inflammation decreased as mast cells increased. The accumulation of mast cells at the visible line of demarcation between normal and abnormal mucosa suggests mast cells play a critical role in either accelerating the process of inflammation or in suppressing continued extension of the disease.