Nodular lymphoid hyperplasia: A marker of low-grade inflammation in irritable bowel syndrome?

Mucosa-Associated Microbiota Dysbiosis in the Terminal Ileum Correlates With Bowel Symptoms in Diarrhea-Predominant Irritable Bowel Syndrome

INTRODUCTION

The mucosa-associated microbiota (MAM) is not as frequently studied in diarrhea-predominant irritable bowel syndrome (IBS-D) compared with the fecal microbiota. In this study, we examined the MAM in the terminal ileum and its correlation with bowel symptoms in IBS-D.

METHODS

Mucosal biopsies of the terminal ileum from 25 patients with IBS-D and 25 healthy controls were collected for 16S ribosomal RNA gene sequencing. Correlation analysis was performed.

RESULTS

Compared with healthy controls, the MAM in the terminal ileum showed a decreased alpha diversity in the IBS-D cohort (Chao1 and Shannon indexes, P < 0.05). And the overall MAM profile clustered separately into 2 groups (ADONIS [PERMANOVA, permutational multivariate analysis of variance], P < 0.05). At the phylum level, the relative abundance of Proteobacteria was significantly higher in the ileal MAM of patients with IBS-D while that of Firmicutes was significantly lower. At the genus level, the relative abundance of Pseudomonas was significantly higher in the IBS-D cohort, with lower Bacteroides and Ruminococcus . Moreover, 40.0% of patients with IBS-D had multiple small nodules (nodular lymphoid hyperplasia) on the mucosal surface of the terminal ileum, which indicated a low-grade inflammation. In patients with IBS-D with nodular lymphoid hyperplasia, the changes of Pseudomonas and Bacteroides were more overt. Correlation analysis revealed that the relative abundance of Pseudomonas positively correlated with abdominal pain and the severity of IBS.

DISCUSSION

Patients with IBS-D showed a dysbiosis of MAM in the terminal ileum, which may be associated with bowel symptoms. Moreover, 40.0% of them displayed mucosal low-grade inflammation, with a more severe mucosal microbial disturbance.

Characterization of the mucosal microbiota in patients with nodular lymphoid hyperplasia with concurrent irritable bowel syndrome compared to healthy controls

BACKGROUND

Nodular lymphoid hyperplasia (NLH) is known as a lymphoproliferative lesion in which multiple small nodules appear on the intestinal wall. It has been documented that patients who struggle with irritable bowel syndrome (IBS) are at greater risk of developing NLH. Here, we aimed to investigate the previously reported pathogens and the abundance of a selection of mucosal microbiota in IBS + NLH patients compared to IBS, and healthy controls.

METHODS AND RESULTS

Terminal ileum biopsies were collected from 37 IBS + NLH, 37 IBS, and 29 healthy controls. Bacterial culture and PCR was performed to detect the presence of pathogens in biopsies. A qPCR assay was applied to assess the abundance of a selection of bacterial taxa. Totally, five bacterial isolates including two enteropathogenic and one enteroaggregative Escherichia coli (EPEC, EAEC), one enterotoxigenic Staphylococcus aureus (SEA), and one Yersinia enterocolitica strains were detected among the IBS + NLH cases. The relative abundance of Bacteroidetes and Streptococcus spp. in IBS + NLH patients was significantly less than IBS and healthy controls. Firmicutes, Pseudomonas spp., Haemophilus spp., and Campylobacter spp. were notably more abundant in IBS + NLH than in IBS patients. The abundance of Verrucomicrobia was higher in NLH + IBS than in healthy controls. Actinobacteria was also significantly more abundant among NLH + IBS patients than the controls.

CONCLUSION

Our results demonstrated that mucosal microbiota composition in NLH + IBS patients slightly differs from that of IBS patients and healthy controls. Further research using large-scale cohorts are needed to enhance current understanding of the contribution of the mucosal microbiota to NLH pathogenesis with concurrent IBS.

The Effects of the Food Additive Titanium Dioxide (E171) on Tumor Formation and Gene Expression in the Colon of a Transgenic Mouse Model for Colorectal Cancer

Titanium dioxide (TiO2) is present in many different food products as the food additive E171, which is currently scrutinized due to its potential adverse effects, including the stimulation of tumor formation in the gastrointestinal tract. We developed a transgenic mouse model to examine the effects of E171 on colorectal cancer (CRC), using the Cre-LoxP system to create an Apc-gene-knockout model which spontaneously develops colorectal tumors. A pilot study showed that E171 exposed mice developed colorectal adenocarcinomas, which were accompanied by enhanced hyperplasia in epithelial cells, lymphatic nodules at the base of the polyps, and increased tumor size. In the main study, tumor formation was studied following the exposure to 5 mg/kgbw/day of E171 for 9 weeks (Phase I). E171 exposure showed a statistically nonsignificant increase in the number of colorectal tumors in these transgenic mice, as well as a statistically nonsignificant increase in the average number of mice with tumors. Gene expression changes in the colon were analyzed after exposure to 1, 2, and 5 mg/kgbw/day of E171 for 2, 7, 14, and 21 days (Phase II). Whole-genome mRNA analysis revealed the modulation of genes in pathways involved in the regulation of gene expression, cell cycle, post-translational modification, nuclear receptor signaling, and circadian rhythm. The processes associated with these genes might be involved in the enhanced tumor formation and suggest that E171 may contribute to tumor formation and progression by modulation of events related to inflammation, activation of immune responses, cell cycle, and cancer signaling.

Mucosal bacterial dysbiosis in patients with nodular lymphoid hyperplasia in the terminal ileum

BACKGROUND

Nodular lymphoid hyperplasia (NLH) in the small intestine is a rare benign lesion characterized by multiple small nodules on the intestinal surface. Patients with terminal ileal NLH may experience long-term abdominal pain, diarrhea, and abdominal distension, among other symptoms. Supplementation with probiotics could mitigate these symptoms. NLH is linked to the immune system, and it may result from accumulation of plasma-cell precursors due to a maturational defect during the development of B lymphocytes. The intestinal microbiome plays an essential role in the immune system. Thus, we speculate that the gut flora plays a key role in terminal ileal NLH.

AIM

To explore the correlation between intestinal flora and terminal ileal NLH.

METHODS

We collected mucosal biopsy samples that were obtained via colonoscopy from 15 patients with terminal ileal NLH (the test group) and 15 normal subjects (the control group). We subsequently performed 16S-rRNA gene amplicon sequencing of these samples, and the results were evaluated using alpha diversity, beta diversity and microbial composition analyses. The Phylogenetic Investigation of Communities by Reconstruction of Unobserved States was used to predict the metabolic pathways and orthologous groups according to the Kyoto Encyclopedia of Genes and Genomes database.

RESULTS

Compared with the control group, the terminal ileal NLH group showed an increased alpha diversity (P < 0.05). The overall intestinal microbiota in the NLH group was significantly different from that of the control group (P < 0.05), implying that there was the dysbiosis in the terminal ileal NLH patients. The relative abundance of phylum Bacteroidetes was significantly lower in the NLH group, while that of Patescibacteria and Campilobacterota was significantly higher. The genus Bacteroides was the dominant gut microbiota in both groups, but its abundance was significantly lower in the test group than it was in the control group. Conversely, the relative abundances of Haemophilus, Streptococcus, Pseudomonas, Actinomyces, TM7X, Fusobacterium nucleatum, Parvimonas, Granulicatella, Helicobacter, and the [Eubacterium] nodatum group were significantly higher in the test group than they were in the control group. In addition, several altered metabolic pathways, orthologous groups, and modules were found. For example, the Peptidoglycan biosynthesis and Aminoacyl tRNA biosynthesis were both increased in the test group.

CONCLUSION

Maintaining the microbial balance and supplementing targeted protective bacteria could improve symptoms and potentially reduce the risk of lymphoma transformation in patients with terminal ileal NLH.

Nodular lymphoid hyperplasia of terminal ileum: how to avoid overdiagnosis of Crohn's terminal ileitis in MR enterography?

PURPOSE

To investigate the magnetic resonance enterography (MRE) characteristics of nodular lymphoid hyperplasia (NLH) and Crohn's terminal ileitis (CTI).

METHODS

Of 1552 MREs from November 2011 to July 2018, 61 individuals with biopsy-proven NLH (n = 24) and CTI (n = 37, 27 with active CTI) were selected based on the inclusion criteria. NLH cases were also followed up for median (range) of 40 (21-61) months. Two board-certified radiologists, blind to clinical data and diagnosis, reviewed MRE in consensus. Conventional, morphological, enhancement, and diffusion parameters were assessed. Mann-Whitney, χ², and logistic regression analyses were conducted.

RESULTS

No NLH patient developed inflammatory bowel disease or lymphoproliferative disorders during the follow-up. Serosal surface irregularity (65% vs. 8%), pseudo-diverticula (27% vs. 0), and mesenteric fat involvement (38% vs. 4%) were more frequent in CTI than NLH (p < 0.01), while mucosal nodularity was more prevalent in NLH (71%) than CTI (19%) (p < 0.001). The upstream luminal diameter (15.0 vs. 12.5 mm, p = 0.015) and mural thickness (6.0 vs. 4.0 mm, p < 0.001) of the terminal ileum showed higher values in CTI than NLH.

CONCLUSIONS

Unlike enhancement and diffusion parameters, morphological features (mucosal nodularity, serosal surface irregularity, and mesenteric fat involvement) could distinguish NLH from CTI regardless of CTI activity.

Case Report: Intestinal Nodular Lymphoid Hyperplasia as First Manifestation of Activated PI3Kδ Syndrome Due to a Novel PIK3CD Variant

Nodular lymphoid hyperplasia (NLH) is a lymphoproliferative disease caused by non-clonal expansion of lymphoid cells in the gut mucosa. Little is known about the pathogenesis of NLH, which is often disregarded as an insignificant or para-physiologic phenomenon. We present the case of a girl with isolated diffuse NLH (extending from the stomach to the rectum) caused by activated PI3Kδ syndrome (APDS) due to the novel p.Glu525Gly variant in PIK3CD. The gain-of-function effect of the variant was confirmed by demonstration of over activation of the Akt/mTOR pathway in the patient's cells. APDS diagnosis led to treatment with sirolimus, which resulted in the complete remission of NLH and in the prevention of extra intestinal complications. In conclusion, we identify APDS as a novel cause of isolated NLH and suggest that patients with severe pan-enteric NLH should be screened for this disorder that may not be apparent on first-line immunological testing.

Ileocolonic Lymphonodular Hyperplasia in Children Related to Etiologies Ranging from Food Hypersensitivity to Familial Mediterranean Fever

OBJECTIVE

We aimed to share our observations on the demographics, clinical characteristics, and outcomes of lymphonodular hyperplasia (LNH) in children.

SUBJECTS AND METHODS

The study included children on whom colonoscopy was performed between January 2015 and May 2018 (n = 361). Demographics, treatment modalities, and outcomes of the patients with LNH were recorded.

RESULTS

LNH was found in 66 patients (18.3%; mean age 8.6 ± 5.96 years, 59.1% male). We found that the etiologic factors were food hypersensitivity (FH) in 25 (37.8%), nonspecific colitis in 12 (18.2%), irritable bowel syndrome in 10 (15.2%), familial Mediter-ranean fever in 7 (10.6%), primary immunodeficiency in 4 (6.1%), and intestinal dysmotility, oxyuriasis, Crohn's disease, and giardiasis in 1 (1.5%) patient. Additionally, in the genetic analysis of patients with idiopathic LNH (n = 4), we detected heterozygote MEFV mutations in all. Cow's milk and egg (25%) were the most common allergens in patients with FH. Symptoms of all patients (n = 25) improved after an elimination diet.

CONCLUSIONS

LNH is a common finding in pediatric colonoscopies with a variety of etiologies ranging from FH and familial Mediterranean fever to immunodeficiency.

Functional gastrointestinal disorders in women with systemic lupus erythematosus: A case-control study

BACKGROUND

Systemic lupus erythematosus (SLE) is an autoimmune disease with multisystemic involvement. Gastrointestinal (GI) manifestations are frequent but functional gastrointestinal disorders (FGIDs) have scarcely been studied in SLE. To determine the prevalence of FGIDs and their potential risk factors in SLE female patients vs controls.

METHODS

Systemic lupus erythematosus patients meeting the American College of Rheumatology (ACR) criteria and controls completed the Rome III questionnaire for FGIDs and a structured interview to assess sociodemographic, clinical, and treatment variables after excluding organic GI diseases. Logistic regression was used to determine risk factors (ie, alcohol drinking, medications) for FGIDs.

KEY RESULTS

Responders included 113 SLE patients and 122 age-matched controls. The presence of at least one FGIDs was higher in SLE (73.4%) vs controls (54.1%), P = .003. The most frequent FGIDs in SLE patients were nausea and vomiting disorders (NVD), belching disorders, globus, anorectal pain, functional heartburn (FH), and functional bloating (FB). After adjustment for confounding variables, SLE was associated with NVD (OR: 7.1, 95% CI: 2.7-19.1) globus (3.5, 1.3-9.3), anorectal pain (3.4, 1.4-8.4), and FH (2.5, 1.5-4.4). The simultaneous presence of >1 FGID was more common in SLE patients than controls (69.8% vs 31.8%). Glucocorticoids (5.2, 1.3-19.9) and non-steroidal anti-inflammatory drugs (NSAIDs; 3.0, 1.1-8.0) were associated with any FGID in SLE patients while alcohol drinking with gallbladder/sphincter of Oddi disorders 7.4 (1.1-47.3).

CONCLUSIONS AND INFERENCES

Functional gastrointestinal disorders are more frequent in SLE patients compared with controls. Medication that may alter gastrointestinal homeostasis, such as glucocorticoids and NSAIDs, are potential risk factors for FGIDs in SLE.