The gut-brain and gut-macrophage contribution to gastrointestinal dysfunction with systemic inflammation.

The gastrointestinal tract is one of the main organs affected during systemic inflammation and disrupted gastrointestinal motility is a major clinical manifestation. Many studies have investigated the involvement of neuroimmune interactions in regulating colonic motility during localized colonic inflammation, i.e., colitis. However, little is known about how the enteric nervous system and intestinal macrophages contribute to dysregulated motility during systemic inflammation. Given that systemic inflammation commonly results from the innate immune response against bacterial infection, we mimicked bacterial infection by administering lipopolysaccharide (LPS) to rats and assessed colonic motility using ex vivo video imaging techniques. We utilized the Cx3cr1-Dtr rat model of transient depletion of macrophages to investigate the role of intestinal macrophages in regulating colonic motility during LPS infection. To investigate the role of inhibitory enteric neurotransmission on colonic motility following LPS, we applied the nitric oxide synthase inhibitor, Nω-nitro-L-arginine (NOLA). Our results confirmed an increase in colonic contraction frequency during LPS-induced systemic inflammation. However, neither the depletion of intestinal macrophages, nor the suppression of inhibitory enteric nervous system activity impacted colonic motility disruption during inflammation. This implies that the interplay between the enteric nervous system and intestinal macrophages is nuanced, and complex, and further investigation is needed to clarify their joint roles in colonic motility.

Hemodynamic Parameters in Spontaneously Hypertensive Rats with Obesity and Chemically Induced Colitis during Probiotic Therapy.

We studied the dynamics of the main hemodynamic parameters in spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats with visceral obesity and chemically induced colitis (CIC) against the background of probiotic therapy. Systolic BP, HR, and body temperature were recorded over 36 days using a wireless telemetry system. During 8 days (3 days before CIC induction and until the end of the experiment) the animals were intragastrically administered a probiotic based on Lactobacillus delbrueckii D5 strain. At baseline, systolic BP was significantly higher in the SHR group, while HR and body temperature did not differ in SHR and WKY rats. On day 8 after CIC induction, systolic BP, HR, and body temperature in SHR were significantly increased in comparison with the initial values. In the group of WKY rats, all indices at the end of the experiment remained at the initial levels. Probiotic therapy in SHR, in contrast to WKY rats, did not lead to normalization of body temperature and hemodynamic disorders resulting from CIC.

Clinical and atopic features of patients with primary eosinophilic colitis: an Italian multicentre study.

Eosinophilic colitis (EC) is the rarest among primary eosinophilic gastrointestinal disorders (EGID). EC is underdiagnosed due to its blurred and proteiform clinical manifestations. To explore the clinical and atopic characteristic of EC adult patients, the diagnostic delay, and relapse-associated factors, by comparison with patients with eosinophilic esophagitis (EoE) and irritable bowel syndrome (IBS). EC patients followed-up at four clinics were included, and clinical, histopathological, and laboratory data were retrieved. As control groups, age-matched patients with EoE and IBS were recruited. Allergy tests included skin prick test and serum specific IgE. Diagnostic delay was assessed. Overall, data from 73 patients were retrieved, including 40 with EC (median age 39 years IQR 22.5-59, F:M 2.1:1), 12 with EoE (F:M ratio: 1:5), and 21 with IBS (F:M ratio: 1:0.9). The most common features in EC patients were female sex (67.5%), atopy (77.5%), abdominal pain/distention (70%), diarrhoea (77.5%), and faecal calprotectin elevation (22.5%). Blood eosinophils were elevated in EoE, but not in EC (p < 0.001), while ECP did not differ across the three groups (p = 0.4). The frequency of allergen sensitization reached 25% of patients. Several frequent pan-allergens for this region were present. The overall diagnostic delay was 10 months (IQR 4-15). Factors contributing to a greater diagnostic delay were atopy, weight loss, and a previous misdiagnosis. EC is mostly a diagnosis of exclusion, burdened by a substantial diagnostic delay. In female patients the presence of allergen sensitization, abdominal symptoms and faecal calprotectin elevation should raise the suspicion of EC.

Chitin-glucan improves important pathophysiological features of irritable bowel syndrome.

BACKGROUND: Irritable bowel syndrome (IBS) is one of the most frequent and debilitating conditions leading to gastroenterological referrals. However, recommended treatments remain limited, yielding only limited therapeutic gains. Chitin-glucan (CG) is a novel dietary prebiotic classically used in humans at a dosage of 1.5-3.0 g/d and is considered a safe food ingredient by the European Food Safety Authority. To provide an alternative approach to managing patients with IBS, we performed preclinical molecular, cellular, and animal studies to evaluate the role of chitin-glucan in the main pathophysiological mechanisms involved in IBS. AIM: To evaluate the roles of CG in visceral analgesia, intestinal inflammation, barrier function, and to develop computational molecular models. METHODS: Visceral pain was recorded through colorectal distension (CRD) in a model of long-lasting colon hypersensitivity induced by an intra-rectal administration of TNBS [15 milligrams (mg)/kilogram (kg)] in 33 Sprague-Dawley rats. Intracolonic pressure was regularly assessed during the 9 wk-experiment (weeks 0, 3, 5, and 7) in animals receiving CG (n = 14) at a human equivalent dose (HED) of 1.5 g/d or 3.0 g/d and compared to negative control (tap water, n = 11) and positive control (phloroglucinol at 1.5 g/d HED, n = 8) groups. The anti-inflammatory effect of CG was evaluated using clinical and histological scores in 30 C57bl6 male mice with colitis induced by dextran sodium sulfate (DSS) administered in their drinking water during 14 d. HT-29 cells under basal conditions and after stimulation with lipopolysaccharide (LPS) were treated with CG to evaluate changes in pathways related to analgesia (µ-opioid receptor (MOR), cannabinoid receptor 2 (CB2), peroxisome proliferator-activated receptor alpha, inflammation [interleukin (IL)-10, IL-1b, and IL-8] and barrier function [mucin 2-5AC, claudin-2, zonula occludens (ZO)-1, ZO-2] using the real-time PCR method. Molecular modelling of CG, LPS, lipoteichoic acid (LTA), and phospholipomannan (PLM) was developed, and the ability of CG to chelate microbial pathogenic lipids was evaluated by docking and molecular dynamics simulations. Data were expressed as the mean ± SEM. RESULTS: Daily CG orally-administered to rats or mice was well tolerated without including diarrhea, visceral hypersensitivity, or inflammation, as evaluated at histological and molecular levels. In a model of CRD, CG at a dosage of 3 g/d HED significantly decreased visceral pain perception by 14% after 2 wk of administration (P < 0.01) and reduced inflammation intensity by 50%, resulting in complete regeneration of the colonic mucosa in mice with DSS-induced colitis. To better reproduce the characteristics of visceral pain in patients with IBS, we then measured the therapeutic impact of CG in rats with TNBS-induced inflammation to long-lasting visceral hypersensitivity. CG at a dosage of 1.5 g/d HED decreased visceral pain perception by 20% five weeks after colitis induction (P < 0.01). When the CG dosage was increased to 3.0 g/d HED, this analgesic effect surpassed that of the spasmolytic agent phloroglucinol, manifesting more rapidly within 3 wk and leading to a 50% inhibition of pain perception (P < 0.0001). The underlying molecular mechanisms contributing to these analgesic and anti-inflammatory effects of CG involved, at least in part, a significant induction of MOR, CB2 receptor, and IL-10, as well as a significant decrease in pro-inflammatory cytokines IL-1b and IL-8. CG also significantly upregulated barrier-related genes including muc5AC, claudin-2, and ZO-2. Molecular modelling of CG revealed a new property of the molecule as a chelator of microbial pathogenic lipids, sequestering gram-negative LPS and gram-positive LTA bacterial toxins, as well as PLM in fungi at the lowesr energy conformations. CONCLUSION: CG decreased visceral perception and intestinal inflammation through master gene regulation and direct binding of microbial products, suggesting that CG may constitute a new therapeutic strategy for patients with IBS or IBS-like symptoms.

Promoting inflammatory lymphangiogenesis by vascular endothelial growth factor-C (VEGF-C) aggravated intestinal inflammation in mice with experimental acute colitis

Angiogenesis and lymphangiogenesis are thought to play a role in the pathogenesis of inflammatory bowel diseases (IBD). However, it is not understood if inflammatory lymphangiogenesis is a pathological consequence or a productive attempt to resolve the inflammation. This study investigated the effect of lymphangiogenesis on intestinal inflammation by overexpressing a lymphangiogenesis factor, vascular endothelial growth factor-C (VEGF-C), in a mouse model of acute colitis. Forty eight-week-old female C57BL/6 mice were treated with recombinant adenovirus overexpressing VEGF-C or with recombinant VEGF-C156S protein. Acute colitis was then established by exposing the mice to 5% dextran sodium sulfate (DSS) for 7 days. Mice were evaluated for disease activity index (DAI), colonic inflammatory changes, colon edema, microvessel density, lymphatic vessel density (LVD), and VEGFR-3mRNA expression in colon tissue. When acute colitis was induced in mice overexpressing VEGF-C, there was a significant increase in colonic epithelial damage, inflammatory edema, microvessel density, and neutrophil infiltration compared to control mice. These mice also exhibited increased lymphatic vessel density (73.0±3.9 vs 38.2±1.9, P<0.001) and lymphatic vessel size (1974.6±104.3 vs 1639.0±91.5, P<0.001) compared to control mice. Additionally, the expression of VEGFR-3 mRNA was significantly upregulated in VEGF-C156S mice compared to DSS-treated mice after induction of colitis (42.0±1.4 vs 3.5±0.4, P<0.001). Stimulation of lymphangiogenesis by VEGF-C during acute colitis promoted inflammatory lymphangiogenesis in the colon and aggravated intestinal inflammation. Inflammatory lymphangiogenesis may have pleiotropic effects at different stages of IBD.

Evaluation by computerized morphometry of histopathological alterations of the colon wall in segments with and without intestinal transit in rats / Avaliação por morfometria computadorizada das alterações histopatológicas da parede cólica em segmentos com e sem trânsito intestinal em ratos

PURPOSE: To evaluate histopathological alterations of the colon wall in segments with and without intestinal transit, by computer-assisted imaging, and to correlate these with the length of time diversion. METHODS: Thirty male Wistar rats were subjected to intestinal transit diversion by a proximal colostomy and distal mucosa fistula. The animals were divided into three experimental groups according to how long after the initial surgical procedure they were sacrificed: six, twelve and eighteen weeks. Colon segments with and without transit were subjected to histopathological study. The variables colon crypt length, mucosal ulceration, muscle layer thickness of the muscularis mucosa, submucosa and muscularis propria, vascular congestion, number of caliciform cells, inflammatory grade and degree of inflammation, comparing the two colon segments in the different experimental groups were studied. Intestinal crypt length, muscle layer thickness of the mucosa, submucosa and muscularis propria and caliciform cells were measured by computer-assisted imaging method. Mean equality, variance analysis and correlation tests were used in the statistical analysis, and the significance level was set at 5 percent. RESULTS: Comparison between segments with and without transit showed that the latter presented reduced length of colon crypts and increased muscle layer thickness of the muscularis mucosa, submucosa and muscularis propria. There were greater quantities of ulceration of the mucosal and greater degree of inflammation with increasing time without transit. Mucosal ulceration, submucosal vascular congestion, increased thickness of the submucosal and muscularis propria layers, presence of caliciform cells, inflammatory infiltrate and inflammatory grade correlated significantly with the length of time without transit. CONCLUSIONS: Histological alterations occurred in all layers of the colon wall, in the segments without intestinal transit. Ulcerations...

OBJETIVO: Avaliar por método de imagem assistida por computador as alterações histopatológicas da parede cólica em segmentos providos e desprovidos de trânsito intestinal e relacioná-las ao tempo de exclusão. MÉTODOS: Trinta ratos Wistar machos foram submetidos à derivação do trânsito no cólon esquerdo por meio de colostomia proximal e fístula mucosa distal. Os animais foram divididos em três grupos experimentais segundo o sacrifício ter sido realizado seis, doze e dezoito semanas após o procedimento cirúrgico inicial. Segmentos dos cólons providos e desprovidos de trânsito foram submetidos a estudo histopatológico. Foram analisadas as variáveis: comprimento das criptas cólicas, ulceração na mucosa, espessura das camadas muscular da mucosa, submucosa e muscular própria, congestão vascular, número de células caliciformes e graduação inflamatória comparando os dois segmentos cólicos nos diferentes grupos experimentais. As variáveis, comprimento das criptas intestinais, espessura das camadas muscular da mucosa, submucosa e muscular própria foram mensuradas por método de imagem assistida por computador. Na análise estatística foram utilizados testes de igualdade de médias e medianas, análise de variância e correlação estabelecendo-se nível de significância de cinco por cento. RESULTADOS: A exclusão de trânsito mostrou-se associada à redução do comprimento das criptas cólicas, aumento da espessura das camadas muscular da mucosa, submucosa e muscular própria. Verificou-se maior quantidade de ulcerações na mucosa e maior grau de inflamação com o progredir do tempo de exclusão. Houve correlação significante entre as ulcerações da mucosa, congestão vascular da submucosa, aumento da espessura das camadas submucosa e muscular própria, presença de células caliciformes, infiltrado inflamatório, graduação inflamatória e o tempo de exclusão de trânsito. CONCLUSÕES: Alterações histológicas ocorrem em todas as camadas da parede cólica, em segmentos sem...

Análise tensional e morfológica da anastomose colônica na colite induzida por ácido acético a 10 por cento, em ratos Wistar, tratados com extrato aquoso de aroeira-do-sertão a 10 por cento (Myracrodruon urundeuva fr. all.) / Tensional and morphologic analysis of the colonic anastomosis on 10 percent acetic acid induced colitis, in Wistar rats, treated with 10 percent aroeira-do-sertão (Myracrodruon urundeuva fr. all.) aqueous extract

OBJETIVO: Verificar, do ponto de vista tensional e morfológico, o efeito do extrato aquoso de aroeira-do-sertão a 10 por cento na anastomose colônica, na vigência de colite induzida por ácido acético a 10 por cento, em ratos Wistar. MÉTODOS: Foram utilizados 48 ratos da linhagem Wistar, distribuídos em dois grupos. Todos os animais foram submetidos à indução da colite por solução aquosa de ácido acético a 10 por cento. Vinte e quatro horas após, os animais foram submetidos à laparotomia, colotomia transversa total e anastomose término-terminal com fio de polipropileno 5-0. Grupo A (veículo), animais tratados com veículo à base de carboximetilcelulose. Grupo B (aroeira), animais tratados com extrato aquoso de aroeira a 10 por cento. Ambos tratamentos foram sob a forma de enema. Os grupos A e B foram distribuídos em subgrupos A3, A7, A14 e A21; B3, B7, B14 e B21, respectivamente, conforme a data prevista para a eutanásia (3, 7, 14 e 21 dias). Nas respectivas datas, os animais foram relaparotomizados, o segmento colônico contendo a anastomose foi ressecado, submetido ao teste de pressão e em seguida à análise histológica. Para o estudo morfológico, as lâminas foram coradas com hematoxilina-eosina e avaliou-se a condição de cicatrização baseado numa tabela de escores que variava de 0 a 16. Quanto maior o escore melhor o grau de cicatrização. RESULTADOS: Na avaliação do estudo morfológico, que quantifica a evolução e o grau de cicatrização, como resultado final do processo cicatricial, o grupo aroeira foi superior ao grupo veículo (p<0,05) no vigésimo primeiro dia, mostrando maior rapidez na reparação tecidual que se dá por regeneração e não por fibrose. Com relação ao teste de tensão, houve diferença estatisticamente significante no dia 3, com predominância do grupo aroeira sobre o grupo veículo (p<0,05). CONCLUSÃO: O extrato aquoso de aroeira-do-sertão a 10 por cento, tem atividade cicatrizante na anastomose colônica na vigência de colite induzida por ácido acético a 10 por cento. Melhora a resistência à tensão na zona da anastomose colônica no 3° dia.

Colitis por desfuncionalización colónica / Acute colitis on a desfuntionalized colon

Antecedentes: la colitis por desviación del flujo fecal se produce por desfuncionalización de la mucosa colónica. La patogénesis es desconocida, pero la hipótesis más firme considera que se debe a la alteración de la flora local, con disminución de la producción de ácidos grasos de cadena corta: n-butírico, propiónico y acético. Objetivo: se hace una puesta al día del tema y se presentan cuatro casos clínicos de desfuncionalización colónica, haciendo una evaluación clínica, videocolonoscópica y anatomopatológica de los mismos. Marco de aplicación: se presentan pacientes atendidos en el servicio de cirugía del Hospital Alemán que por distintos motivos mantuvieron una colostomía derivativa por más de tres meses. Resultados: de los cuatro pacientes, sólo uno presentaba el cuadro completo, con manifestaciones clínicas, colonoscópicas y anatomopatológicas. Los tres restantes no tuvieron manifestaciones clínicas, ni colonoscópicas, pero uno de ellos tuvo alteraciones histológicas. Conclusiones: la colitis por desfuncionalización es una patología que aparece reiteradamente pero con pocas manifestaciones clínicas. No se piensa en ella con frecuencia y como consecuencia, suele ser subdiagnosticada. El tratamiento ideal consiste en la restitución del tránsito intestinal. Cuando éste no es posible, la aplicación local por enema de ácidos grasos de cadena corta mejora o hace desaparecer los síntomas. El diagnóstico diferencial con la colitis ulcerosa y la enfermedad de Crohn es muy importante, dado que en estos casos la restitución del flujo fecal estaría contraindicado.

Colitis colagenosa: revisión clinicopatológica y presentación de un caso / Collagenous colitis. A clinical-pathologic review and presentation of a case

Se presenta el caso de una paciente del sexo femenino de 52 años de edad, con un cuadro diarreico de ocho meses de evolución y una pérdida de 10 kg de peso, con estudios radiológicos y endoscopidos del recto y del sigmoides sin alteraciones aparentes. La biopsia del recto mostró cambios imflamatorios correspondientes a una colitis colagenosa. La paciente fue tratada con 3 g diarios de sulfasalazina durante ocho semanas, obteniéndose una remisión total de la sintomatología. Se hace una revisión del tema y se enfatiza el diagnóstico diferencial clínico e histológico