Cytokine Profile and Immunoglobulin E-mediated Serological Food Hypersensitivity in Patients With Irritable Bowel Syndrome With Diarrhea

The Cutting Edge Research of Functional Gastrointestinal Disorders in Japan: Review on JGA Core Symposium 2018-2020

Highly impacted articles on functional gastrointestinal (GI) disorders research presented at the core symposium held in the Japanese Gastroenterological Association (JGA) annual meeting 2018-2020 are selected and summarized. Regarding visceral hypersensitivity and sensor in GI tracts, transient receptor potential vanilloid 4 ion channel and acid-sensitive ion channel were candidates for hypersensitivity in GI tracts. ATP release from vesicular nucleotide transporter may be a key pathway to sensitize the nerve endings. Regarding inflammation and mucosal immune responses, patients infected with H. pylori having Ser70 type single nucleotide polymorphism of NapA gene was associated with H. pylori-related dyspepsia via gastric dysmotility. Gastric histology infected with Ser70 type NapA was shown severe infiltration of neutrophils into intramuscular layer. Macrophages, mast cells, and neutrophils are infiltrated in the colon of irritable bowel syndrome (IBS) patients and the locally produced IL-1β upregulated brain-derived neurotrophic factor (BDNF) in enteric glia cells. BDNF can also stimulate nerve endings and might be linked to pain in the colon. Dysbiosis in the composition of commensal bacteria communities is associated with the pathogenesis of various diseases including IBS and gut-brain interaction. The investigation on the mucosa-associated microbiota (MAM) is essential for understanding the interactions. The α-diversity and β-diversity of MAM indices are significantly different among IBS-D, IBS-C, and controls, and the different diversity might contribute to the pathophysiology of IBS. As research works on psychosocial factors show, maternal separation animal model was used and it is early life stress. The stress had induced colonic hyper-contraction, gastric hypersensitivity, and delayed emptying. The precise molecular mechanisms are still under investigations.

Food Hypersensitivity in Children Aged 0-3 Years of the Lviv Region in Ukraine: A Cross-Sectional Study

Aim: To determine the prevalence and to estimate factors associated with food hypersensitivity in young children of the Lviv region in Ukraine. Methods: A prospective cross-sectional survey study was conducted between 2016 and 2017 in the Lviv region of Ukraine. A specially designed questionnaire about food hypersensitivity of young children developed and validated by M. J. Flokstra-de Blok was used after translation into the Ukrainian language. The questionnaire included 34 questions, grouped into general and detailed information. Parents of children aged 0-3 years were asked to complete the questionnaire at pre-schools and medical institutions. Results: Among 4,500 distributed questionnaires, 3,214 (71%) were completed and processed. Parents reported that 25% of their young children had food hypersensitivity. According to the survey the most common agents involved in food hypersensitivity in young children were cow's milk (34%), egg (28%), and wheat (24%). Hypersensitivity to milk occurred in 50% of children in the age group of 1-2 years. Regional differences associated with food hypersensitivity were also found. Namely, in the Carpathians, there was more hypersensitivity to fish (27%) and honey (22%) than in other regions, while hypersensitivity to soy was detected mostly in Lviv City residents (8.5%). Unknown causes of food hypersensitivity were highly reported (34%) in the Carpathians. Conclusion: Prevalence and some distinctiveness of food hypersensitivity revealed in four geographic and climate zones as well as in Lviv City have a considerable practical use for formulation of recommendations for children with food hypersensitivity.

Food-specific serum IgG and symptom reduction with a personalized, unrestricted-calorie diet of six weeks in Irritable Bowel Syndrome (IBS)

Background

Irritable Bowel Syndrome (IBS) is a widespread disease with variable symptoms that have an important impact on the quality of life. Despite the prevalence of IBS, its etiology and pathophysiology are still to be fully understood, but immune response is known to be involved. In this study, we investigated the variation of two specific cytokines, B-cell activating factor (BAFF) and platelet-activating factor (PAF), the levels of food-specific IgG and the symptom severity, using Irritable Bowel Syndrome—Symptom Severity Score (IBS-SSS), following a personalized and unrestricted-calorie diet.

Methods

We enrolled 30 subjects with diagnosis of IBS, according to Rome-IV criteria, whose inflammatory markers were measured at baseline and after 6 weeks of dietary intervention. The subjects were monitored in a general practice outpatient setting and nutritional advice was offered remotely via two telephone sessions with a nutritionist.

Results

BAFF and PAF values did not differ between baseline and end of study, both in compliant (C) and non-compliant (NC) subjects. IgG levels significantly decreased only in compliant subjects: 37.32 (23.24–93.67) IU/mL; 27.9 (7.56–93.96) IU/mL (p = 0.02) and in non-compliant went from 51.83 (13.17–113.1) IU/mL to 44.06 (4.96–255.4) IU/mL (p = 0.97, ns). IBS-SSS significantly decreased in both compliant subjects, from 245 (110–480) to 110 (0–140) (p < 0.0001), and non compliant subjects, from 250 (155–370) to 100 (7–220) (p < 0.0001). Comparing IBS-SSS between week 3 and week 6, only compliant subjects had a significant reduction, from 155 (50–355) to 110 (0–140) (p = 0.005), versus non-compliant, from 115 (35–315) to 100 (7–220) (p = 0.33, ns).

Conclusion

These findings support the rapid efficacy and suitability of a personalized dietetic intervention with outside consultation in IBS.

Trial registration: ClinicalTrials.gov ID NCT04348760 Registered April 15, 2020 (retrospectively registered) https://clinicaltrials.gov/show/NCT04348760

Mechanism of action and therapeutic benefit of rifaximin in patients with irritable bowel syndrome: a narrative review

Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder with a multifactorial pathophysiology. The gut microbiota differs between patients with IBS and healthy individuals. After a bout of acute gastroenteritis, postinfection IBS may result in up to approximately 10% of those affected. Small intestinal bacterial overgrowth (SIBO) is more common in patients with IBS than in healthy individuals, and eradication of SIBO with systemic antibiotics has decreased symptoms of IBS in some patients with IBS and SIBO. The nonsystemic (i.e. low oral bioavailability) antibiotic rifaximin is indicated in the United States and Canada for the treatment of adults with IBS with diarrhea (IBS-D). The efficacy and safety of 2-week single and repeat courses of rifaximin have been demonstrated in randomized, placebo-controlled studies of adults with IBS. Rifaximin is widely thought to exert its beneficial clinical effects in IBS-D through manipulation of the gut microbiota. However, current studies indicate that rifaximin induces only modest effects on the gut microbiota of patients with IBS-D, suggesting that the efficacy of rifaximin may involve other mechanisms. Indeed, preclinical data reveal a potential role for rifaximin in the modulation of inflammatory cytokines and intestinal permeability, but these two findings have not yet been examined in the context of clinical studies. The mechanism of action of rifaximin in IBS is likely multifactorial, and further study is needed.

Effect of the interleukin 10 polymorphisms on interleukin 10 production and visceral hypersensitivity in Chinese patients with diarrhea-predominant irritable bowel syndrome

Background:

Irritable bowel syndrome (IBS), a functional gastrointestinal disorder, is characterized by cytokine imbalance. Previously, decreased plasma interleukin 10 (IL-10) level was reported in patients with IBS, which may be due to genetic polymorphisms. However, there are no reports correlating the IL-10 polymorphisms with IL-10 production in patients with IBS. This study aimed to analyze the effect of IL-10 polymorphisms on IL-10 production and its correlation with the clinical symptoms in Chinese patients with diarrhea-predominant IBS (IBS-D).

Methods:

Two IL-10 single nucleotide polymorphisms (rs1800871 and rs1800896) were detected in 120 patients with IBS-D and 144 healthy controls (HC) using SNaPshot. IBS symptom severity score, Bristol scale, hospital anxiety, and depressive scale (HADS) were used to evaluate the clinical symptoms, as well as the psychological status and visceral sensitivity of the subjects. IL-10 levels in the plasma and peripheral blood mononuclear cell (PBMC) culture supernatant were measured using enzyme-linked immunosorbent assay, while those in ileal and colonic mucosal biopsies were measured using immunohistochemistry.

Results:

The frequency of rs1800896 C allele was significantly lower in the patients with IBS-D than that in the HC (odds ratio: 0.49, 95% confidence interval: 0.27–0.92, P = 0.0240). The IL-10 levels in the plasma (P = 0.0030) and PBMC culture supernatant (P = 0.0500) of the CT genotype subjects were significantly higher than those in the TT genotype subjects. The CT genotype subjects exhibited a higher pain threshold in the rectal distention test than the TT genotype subjects. Moreover, IL-10 rs1800871 GG genotype subjects showed an increase in the HADS score compared to other genotype subjects.

Conclusions:

IL-10 rs1800896 C allele is correlated with higher IL-10 levels in the plasma and the PBMC culture supernatant, which is associated with a higher pain threshold in the Chinese patients with IBS-D. This study provides an explicit relationship of IL-10 polymorphisms with IL-10 production, which might help in understanding the pathogenesis of IBS-D.

Functional analysis of a novel G87V TNFRSF1A mutation in patients with TNF receptor-associated periodic syndrome

Tumor necrosis factor (TNF) receptor-associated periodic syndrome (TRAPS) is an autoinflammatory disease that is caused by heterozygous mutations in the TNFRSF1A gene. Although more than 150 TNFRSF1A mutations have been reported to be associated with TRAPS phenotypes only a few, such as p.Thr79Met (T79M) and cysteine mutations, have been functionally analyzed. We identified two TRAPS patients in one family harboring a novel p.Gly87Val (G87V) mutation in addition to a p.Thr90Ile (T90I) mutation in TNFRSF1A. In this study, we examined the functional features of this novel G87V mutation. In-vitro analyses using mutant TNF receptor 1 (TNF-R1)-over-expressing cells demonstrated that this mutation alters the expression and function of TNF-R1 similar to that with the previously identified pathogenic T79M mutation. Specifically, cell surface expression of the mutant TNF-R1 in transfected cells was inhibited with both G87V and T79M mutations, whereas the T90I mutation did not affect this. Moreover, peripheral blood mononuclear cells (PBMCs) from TRAPS patients harboring the G87V and T90I mutations showed increased mitochondrial reactive oxygen species (ROS). Furthermore, the effect of various Toll-like receptor (TLR) ligands on inflammatory responses was explored, revealing that PBMCs from TRAPS patients are hyper-responsive to TLR-2 and TLR-4 ligands and that interleukin (IL)-8 and granulocyte-macrophage colony-stimulating factor (GM-CSF) are likely to be involved in the pathogenesis of TRAPS. These findings suggest that the newly identified G87V mutation is one of the causative mutations of TRAPS. Our findings based on unique TRAPS-associated mutations provide novel insight for clearer understanding of inflammatory responses, which would be basic findings of developing a new therapeutic and prophylactic approach to TRAPS.

Electroacupuncture inhibits visceral pain via adenosine receptors in mice with inflammatory bowel disease

To investigate the involvement of peripheral adenosine receptors in the effect of electroacupuncture (EA) on visceral pain in mice with inflammatory bowel disease (IBD). 2,4,6-Trinitrobenzene sulfonic acid (TNBS) was used to induce the visceral pain model. EA (1 mA, 2 Hz, 30 min) treatment was applied to bilateral acupoints "Dachangshu" (BL25) 1 day after TNBS injection once daily for 7 consecutive days. Von Frey filaments were used to measure the mechanical pain threshold. Western blot was used to detect the protein expression levels of adenosine 1 receptor (A1R), adenosine 2a receptor (A2aR), adenosine 2b receptor (A2bR), adenosine 3 receptor (A3R), substance P (SP), and interleukin 1 beta (IL-1β) in colon tissue. EA significantly ameliorated the disease-related indices and reduced the expression of SP and IL-1β in the colon tissues of mice with IBD. EA increased the expression of A1R, A2aR, and A3R and decreased the expression of A2bR in the colon tissue. Furthermore, the administration of adenosine receptor antagonists influenced the effect of EA. EA can inhibit the expression of the inflammatory factors SP and IL-1β by regulating peripheral A1, A2a, A2b, and A3 receptors, thus inhibiting visceral pain in IBD mice.

Follow up on atopy and the gastrointestinal tract - a review of a common association 2018

Primary atopic disorders can be classified as heritable genetic disorders presenting with deregulated pathogenic allergic effector responses irrespective of sensitization. In the last decade, there are parallel rises in the burden of atopic and gastrointestinal (GI) diseases. Areas covered: There is increasing recognition of an association between atopy and GI disease through immune dysregulation, the microbiome and shared genetic pathways. Since the first article on atopy and the GI tract in 2014 in this journal, many more studies have shed light on the shared pathways in these diseases, particularly in the field of eosinophilic GI disease, functional GI disorders, and inflammatory bowel disease. Expert opinion: Understanding the links with common mechanisms in atopy and GI diseases that may lead to better targeting of treatment through manipulation of immune mechanisms, the microbiome, genetics, food allergens and specific GI diseases such as inflammatory bowel disease, functional GI disorders.