Introduction

Food is often reported as a trigger for symptoms in patients with irritable bowel syndrome (IBS). One of the proposed pathophysiological mechanisms is a local immune response to food antigens, triggered by a preceding infection¹.

Aims & Methods

This study aimed to investigate rectal mucosal reactions to food in patients with IBS. Therefore, patients with IBS and food-related symptoms were included. Allergies to the food items that were tested during the colonoscopic antigen provocation (COLAP) were excluded by an allergologist. The COLAP was started in the absence of macroscopic abnormalities during sigmoidoscopy. A 200 μL solution of each food antigen (wheat, gluten, soy, and milk; administered in a randomized order and blinded), a negative control (NaCl 0.9%), and a positive control (histamine) were injected in the rectal mucosa, with a positive reaction defined as mucosal edema 12 minutes after injection and judged based on a previously used semiquantitative scale ². The reaction was independently judged by two endoscopists, resulting in a positive or negative reaction when they agreed and doubtful when they did not.

Results

Data from ten patients were available for this interim analysis. Nine were female, with a median age of 45 [range 24-58] years, and a median IBS symptom severity score of 356 [range 197-416], i.e. in the moderate to severe range. Six patients had predominant constipation, one predominant diarrhea, and three mixed bowel habits. COLAP was positive in seven patients, with a positive reaction for one food antigen in three patients and for two food antigens in four patients. In the other three patients, the test was only doubtful for one of the food antigens (n=2), or negative for all (n=1). A positive reaction to gluten was observed in five patients, to soy in three, to wheat in two, and to milk in one (Table). The reaction to histamine was positive in eight patients, with no positive reaction after injection of the negative control in all.

Conclusion

A local intestinal reaction to food antigens was seen in a subset of patients with IBS. Further research will focus on underlying pathophysiological mechanisms and clinical relevance of these findings.

References

1. Aguilera-Lizarraga J, Florens MV, Viola MF, Jain P, Decraecker L, Appeltans I, et al. Local immune response to food antigens drives meal-induced abdominal pain. Nature. 2021;590(7844):151-6.
2. Bischoff SC, Mayer J, Wedemeyer J, Meier PN, Zeck-Kapp G, Wedi B, et al. Colonoscopic allergen provocation (COLAP): a new diagnostic approach for gastrointestinal food allergy. Gut. 1997;40(6):745-53.

Introduction

Metabolic dysfunction-associated steatotic liver disease (MASLD), formerly referred to as non-alcoholic fatty liver disease (NAFLD), and dyslipidemia are among the most common metabolic disorders worldwide. Disruption of intestinal barrier integrity, as reflected by elevated zonulin levels, has been implicated in insulin resistance and lipid metabolism disorders, contributing to the pathogenesis of MASLD.

Aims & Methods

The aim was to evaluate fecal zonulin levels in patients with dyslipidemia and MASLD, and to explore their potential role as risk factors for disease development and progression. The study included 342 patients with dyslipidemia, among whom MASLD was diagnosed in 152 cases based on ultrasound and steatometry findings. Fecal zonulin levels were measured by ELISA. Small intestinal bacterial overgrowth (SIBO) was diagnosed using hydrogen breath testing. Correlations between zonulin, inflammatory markers (high-sensitivity C-reactive protein, hsCRP), lipid profiles, and SIBO prevalence were analyzed.

Results

SIBO was detected in 45% of patients with dyslipidemia and 53.2% of patients with MASLD. Fecal zonulin levels in patients with MASLD (115±2.76 ng/g) significantly exceeded the normal upper limit (≤107 ng/g) and were higher compared to patients without steatosis. Zonulin levels positively correlated with hsCRP (r=0.65, p<0.05) and triglycerides (r=0.58, p<0.05). A strong negative correlation was observed between SIBO presence and HDL-C levels (r=–0.78, p<0.05) in patients with dyslipidemia.

Conclusion

Elevated zonulin levels and increased intestinal permeability are closely associated with systemic inflammation and lipid metabolism disturbances in MASLD. Zonulin and SIBO may represent novel therapeutic targets for the prevention and treatment of MASLD and metabolic disorders.

Introduction

The highest risk factor of inflammatory bowel disease (IBD) is having a first-degree relative (FDR) with IBD. However, genetic variation accounts for only a small proportion of IBD heritability. Evidence from family and twin studies underscores the role of shared environment for the development of IBD. In a recent study based on two population-based IBD cohorts from South-Eastern Norway, thirty years apart, we reported a substantial increase in the rate of familial IBD (1).

Aims & Methods

This study investigates the potential underlying mechanisms for the increased rate of familial IBD in South-Eastern Norway.
We examine the association between shared environment and gene expression across IBD phenotypes [Crohn’s disease (CD) and ulcerative colitis (UC)] and four comparison groups: (I) multiplex IBD familial patients (≥3 FDRs with IBD), (II) healthy relatives in multiplex IBD families, (III) sporadic IBD patients, and (IV) symptomatic non-IBD controls. Expression analyses focus on four candidate genes, FKBP5, BCL3, VMP1, and TRAIL, previously identified as differentially methylated in IBD compared to controls (2,3). Blood samples were collected from 15 multiplex IBD families in South-Eastern Norway, between April 2023 and January 2024. For comparison, blood samples from 50 sporadic IBD patients and 50 symptomatic controls (SC) were obtained from the IBSEN III cohort (4).
RNA was extracted from PAXgene blood samples of the multiplex families at EpiGen, Akershus University Hospital, Norway, while RNA extractions from the sporadic IBD patients and SCs were performed at The Institute of Clinical Molecular Biology, Kiel, Germany. All cDNA synthesis were carried out at EpiGen. Gene expression was measured using RT-qPCR on cDNA with target-specific primers. Relative quantification was performed using GAPDH and ACTB as housekeeping genes.
Simple t-tests were conducted to compare the mean gene expression between the four comparison groups and across IBD phenotypes.

Results

The multiplex IBD family study included 62 individuals, 41 IBD patients, 25 patients with UC, 16 with CD, and 21 healthy family members, 13 FDR and 8 spouses. The results for the differences in mean fold changes between the four groups, including CD and UC for each of the four candidate genes, are presented in Table 1. The gene expression analysis revealed differences in mean fold changes between the four groups and across CD and UC.
The relative quantification of gene expressions for the four candidate genes revealed no significant differences in gene expression among the IBD patients vs healthy members of multiplex families.
Significant differences were observed for all candidate genes among familial IBD vs sporadic IBD and between healthy multiplex family members vs symptomatic controls, except for BCL3 and TRAIL, respectively. (p<0.005).

Conclusion

Our results reveal associations between the expression levels of IBD candidate genes and shared family environment, suggesting that epigenetic mechanisms may contribute to the development of familial IBD. Further methylation studies are warranted to clarify the underlying mechanisms of changed gene expression.

References

1. Aabrekk TB. Increased familial risk of IBD over thirty years based on twopulation-based IBD incident cohorts conducted in South-Eastern Norway in 1990-1994 (IBSEN I) and in 2017-2019 (IBSEN III). [Abstract]. In press 2024.
2. Ventham NT, Kennedy NA, Adams AT, Kalla R, Heath S, O'Leary KR, et al. Integrative epigenome-wide analysis demonstrates that DNA methylation may mediate genetic risk in inflammatory bowel disease. Nat Commun. 2016;7:13507.
3. Joustra V, Hageman IL, Satsangi J, Adams A, Ventham NT, de Jonge WJ, et al. Systematic Review and Meta-analysis of Peripheral Blood DNA Methylation Studies in Inflammatory Bowel Disease. J Crohns Colitis. 2023;17(2):185-98.
4. Kristensen VA, Opheim R, Perminow G, Huppertz-Hauss G, Detlie TE, Lund C, et al. Inflammatory bowel disease in South-Eastern Norway III (IBSEN III): a new population-based inception cohort study from South-Eastern Norway. Scand J Gastroenterol. 2021;56(8):899-905.

Disclosure

Vendel A. Kristensen har reported scientific advisory boards from Takeda AS, consultant fees from Janssen-Cilag AS and speaker fees from Thermo Fisher Scientific.
Marte Lie Høivik has reported investigator-initiated research grants from Takeda, Pfizer, Tillotts, Ferring and Janssen. Speaker honoraria from Takeda, Tillotts, Ferring, AbbVie, Pfizer, Galapagos, MSD and Meda and Advisory board Takeda, Galapagos, MSD, Lilly, Janssen, Pfizer and AbbVie.
The other authors of this abstract have no Conflict of Interest