Inflammatory Crohn Research Articles

P0133 Activation of Adipose Tissue Browning as a Potential Therapeutic Approach to Reduce Inflammation in Crohn’s Disease

Abstract Background Crohn's Disease (CD) is a chronic autoimmune disorder of the gastrointestinal tract, marked by a persistent pro-inflammatory environment. A hallmark feature is the formation of creeping fat (CrF), an immunologically active adipose tissue that exacerbates inflammation and disease progression (1). Anti-tumor necrosis factor (TNF) therapies, like Infliximab, are widely used to reduce intestinal inflammation in CD. Notably, we showed that Infliximab not only alleviates intestinal inflammation but also affects the behavior of CrF (2). Our previous work demonstrated that a browning process, linked with thermogenic activation in adipose tissue, occurs in CrF of CD patients (3). This process may play a role in regulating inflammation, as suggested by Zuo and colleagues (4), who showed that browning activation enhances anti-inflammatory responses in CrF. Methods Mesenteric adipose tissue, specifically CrF, was collected from CD patients (n=6). Subcutaneous and visceral adipose tissue samples were obtained from non-CD patients undergoing elective surgeries (hernia repairs or colectomies) (n=4). All tissue explants were treated with Infliximab at 5 mg/kg for 24 hours. Additionally, adipose-derived stem cells were isolated from CrF and subcutaneous tissue of both CD and non-CD patients. RNA was extracted from explants and stem cell cultures, and gene expression was analyzed using quantitative PCR. Focus was placed on browning markers (e.g., UCP-1, TMEM26) and cytokines, including TNF, CCL2, IL-4, and IL-10. Results Infliximab-treated CrF explants exhibited a significant increase in browning markers UCP1 and TMEM26 expression. Pro-inflammatory cytokines TNF and CCL2 showed a downward trend, while IL10 expression significantly increased (p = 0.006). In subcutaneous adipose tissue explants from non-CD patients, UCP1 and IL10 expression levels also rose significantly following Infliximab treatment, although no browning markers were upregulated in visceral adipose tissue. Infliximab-treated adipose-derived stem cells from both CD and non-CD patients showed a significant increase in UCP1 and IL4, along with a decrease in TNF expression (p < 0.01). Conclusion Infliximab induces browning in both CD and non-CD patients, suggesting broader therapeutic potential. Additionally, adipose-derived stem cells from both groups showed increased browning markers and anti-inflammatory cytokines in response to Infliximab, underscoring their pivotal role in mediating the browning process and potentially modulating inflammation. These findings suggest that targeting adipose tissue browning could provide a novel therapeutic approach for managing inflammation in CD and related conditions.

P0344 Comparative analysis of a simple POPSIL score with Lémann Index to define the burden of organ damage in Crohn’s disease

Abstract Background Uncontrolled inflammation in Crohn’s disease (CD) can lead to progressive bowel damage such as strictures, fistulae and abscesses. There is currently no practical measure for organ damage that is available for clinicians to use. Presently, the Lémann Index(LI) incorporates analysis of multiple bowel segments and complication coefficient multiplication (with minimum 60 data points) that is difficult to apply in real-world clinical setting(1). We designed a simple score derived from LI to capture risk factors of Penetrating, Organ Involvement, Perianal, Stricturing, Inflammation and Length (POPSIL) that can track the evolution of organ damage in CD and that can be universally applied to routine clinical data (Table 1). Methods We applied the LI and POPSIL score to CD patients from the MUSIC and GI-DAMPs IBD study(www.musicstudy.uk); a prospective 12-month longitudinal study and cross-sectional study following active IBD patients in response to current drug treatment respectively. All participants undergo endoscopic evaluation at baseline and again at 3-6 months for mucosal assessment; and MRI small bowel where clinically indicated. We calculated Pearson correlation coefficients to compare the LI results with the POPSIL score. In addition, we analysed organ damage scores with patient-reported outcomes of wellbeing (CUCQ32) in particular, pain, fatigue and psycho-social welfare. Results In total, of 312 CD patients with complete data, 72 (23.1%) patients had small bowel MRI and colonoscopy data within 60 days (median time between two tests was 26.5 days; IQR 5.75-44.25 days) of recruitment to enable both LI/POPSIL scores to be calculated. In this cohort, median age was 31 years (IQR 26-42), 36 female (50%). A total of 20.8% (n=15) patients were current smokers. The median BMI was 25 (IQR 21.4-29.4). Overall, median LI was 19.5 (IQR 8.3-26.4). Median POPSIL score was 6 (IQR 5-8) where in our cohort POPSIL scores were classified according to severity (Table 1): Mild 3.2% (n=2), Moderate 41.2% (n=26), Severe 49.2% (n=31) and Very Severe 6.4% (n=4). POPSIL score is significantly correlated with LI (r=0.6, p<0.001). CUCQ32 were not correlated with neither LI and POPSIL scores. The time taken to calculate the scores for LI and POPSIL per patient were 3 minutes and 1 minute respectively. Conclusion The POPSIL score has comparable effectiveness to the LI in assessing global bowel damage. Its ease of calculation suggests that it may be a more practical method to assess burden of organ damage over time, response to drug therapy and prognostic determination of disease course. To develop the POPSIL score, we will incorporate patient-reported outcomes and larger scale validation of this approach. References 1)Pariente B, Torres J, Burisch J, et al. Validation and Update of the Lémann Index to Measure Cumulative Structural Bowel Damage in Crohn’s Disease. Gastroenterology. 2021 Sep;161(3):853-864.e13

P1059 Fecal calprotectin response to Tasty&Healthy dietary intervention in asymptomatic children and young adults with biologically active Crohn’s disease: results of the “TASTI-E” randomized controlled trial

Abstract Background Tasty&HealthyTM (T&H) is a whole food diet aimed at alleviating inflammation in Crohn’s disease (CD). It excludes processed food, gluten, red meat, and dairy (except for plain yogurt), but does not include mandatory ingredients or partial enteral nutrition with formula as does the CD Exclusion Diet. In this RCT we evaluated T&H diet as an intervention for persistent subclinical inflammation compared with continuing habitual diet. (NCT#04239248; TASTI-E). Methods Patients with CD, aged 6-40 years, in clinical remission or with minimal symptoms (wPCDAI<20/CDAI<200), were randomized if their MINI-index was ≥8 (i.e. bowel inflammation), to receiving either T&H or continuing their habitual diet for 8 weeks. Patients in the latter group were also offered T&H after completing the initial 8 week randomization period. The primary outcome was calprotectin-defined response (i.e. reduction of >50%). Secondary outcomes included adherence, MINI-index, and CRP. Due to COVID-19-related slow enrolment, the study was terminated early, and thus analyses are exploratory on a per-protocol basis. Results 46 patients were randomized (mean age 18.2±7.6 years; median disease duration 9.01 months, IQR 2.9-17.1); 19 were assigned to T&H and 27 to the habitual group. The primary endpoint was achieved, with 7 patients (37%) in the T&H group achieving calprotectin response, vs 4 (15%) in the habitual group (RR 3.23 [95% CI 1.15-9.01]; p=0.028). A pre-post comparison of 15 patients who completed 8 weeks of habitual diet and crossed-over to T&H, showed higher rates of calprotectin<250 mcg/g at week 16 compared with their baseline at week 8 (47% vs. 17%, p=0.005) and MINI<8 (60% vs 20%, p=0.0013). Additionally, compared with the habitual diet, the improvement in CRP 0.48 (0.18-0.81) vs. 0.36 (0.1-0.36); p=0.0012) and MINI (10 (9-13) vs. 7 (5-10.5); p=0.047) was higher in the T&H arm, respectively. The absence of gluten levels in stool was used as a measure of adherence to the T&H diet. At week 8, only 2/13 patients (15%) in the T&H group tested positive for stool gluten, compared to 18/20 patients (90%) in the habitual diet group (p=0.002), demonstrating high adherence to T&H. Patients in the T&H arm met over 95% of Dietary Reference Intakes (DRI) for key macro- and micronutrients. No significant differences were found between the groups except for higher potassium and fiber in the T&H group (p=0.018 and p<0.001, respectively). Conclusion The T&H diet is effective in reducing inflammation in children and adults with CD who have subclinical inflammation. The flexibility of T&H without the need for formula feeds or mandatory ingredients is associated with high adherence.

DOP071 Distinctive pathogenic memory T cell and neutrophil responses at diagnosis identify CD patients who develop severe therapy resistant disease

Abstract Background CD4+ memory T cells (Tm) drive chronicity of inflammation in Crohn’s disease (CD). Variability in response to treatments specifically targeting Tmem hamper disease management. Recently, we have established that a subgroup of pediatric CD patients with high frequencies of circulating gut-homing IFN-g-secreting ex-Th17/Th1* TIGITneg Tmem at time of diagnosis develop a severe disease course. Specifically, they fail to reach remission within 6 months or lose remission within 1 year, despite anti-TNF treatment. As neutrophils are key targets of Tmem function, we hypothesized that pathogenic gut-homing IFN-g-secreting ex-Th17/Th1* TIGITneg Tmem alter intrinsic neutrophil transcriptional programming at an early stage, before the cells enter the tissue, associating with therapy resistant intestinal disease. Methods We analyzed clinically well-characterized therapy-naive pediatric CD patients (n=33) and IBD-negative controls (IBDneg;n=15) from the PIBD-SETQ cohort at time of diagnosis; performed bulk RNA-seq of purified circulating neutrophils, bulk RNAseq of intestinal biopsies, multiparameter flow cytometry of circulating immune cells and plasma proteomics using Proximity Extension Assay technology. Results At diagnosis, CD neutrophils differentially expressed 263 genes (DEGs) compared to IBDneg neutrophils. CD neutrophil transcriptomes were enriched for pathways related to neutrophil activation, granule biology, and IFN signaling. Hierarchical clustering of CD patients on the basis of the 263 DEGs identified two patient clusters: cluster_1 with a neutrophil transcriptional pattern similar to IBDneg, and cluster_2 with a pronounced enrichment in IFN and TNF signaling and complement genes. In line with our hypothesis, neutrophil cluster_2 patients had higher frequencies of circulating gut-homing IFN-g-secreting ex-Th17/Th1* TIGITneg Tm, reduced frequencies of inhibitory Tm and higher plasma concentrations IFN-g pathway-associated proteins including IFN-γ, CDCP1, and CXCL9 compared to cluster_1 patients. Crucially, lesional colonic biopsies of neutrophil cluster_2 patients were transcriptionally distinct from cluster_1 with a signature of increased IFN-g signaling, extracellular matrix re-organization and Fc-receptor expression but did not differ in the number of infiltrating neutrophils/mm2 or histological disease activity. In line with this distinctive immunotype, cluster_2 patients had higher clinical disease scores, higher endoscopic scores and lower rates of normal FCP remission at 1 year after diagnosis despite similar anti-TNF use compared to cluster_1 patients. Conclusion We define a subgroup of pediatric CD patients who have a distinctive pathogenic Tm-neutrophil immunotype at diagnosis and develop severe therapy resistant disease.

P0115 Selective immune responses to Lachnospiraceae flagellins discriminate therapy-naive pediatric Crohn’s disease patients with distinct host-microbial interaction

Abstract Background Pathogenic CD4+ T-cell responses to commensal microbial antigens drive intestinal inflammation in Crohn’s disease (CD). Both hypo- or hyperactive anti-microbial innate immunity could underlie these aberrant T-cell responses. CD patients have increased IgG and T cell responses against commensal Lachnospiraceae-derived flagellins, which associate with disease complications. We investigated whether CD patients with high anti-Lachnospiraceae flagellin responses at diagnosis have underlying innate hypo- or hyperresponsiveness and high IgG responses to other dysbiotic commensals. Methods IgG reactivity to 19 recombinant flagellins from Lachnospiraceae species colonizing mouse and human gut, was measured in plasma of therapy-naïve pediatric CD patients (n=49) and controls (n=29). In addition, we measured plasma IgG responses to 1 recombinant flagellin and 71 microbial lysates of dysbiotic commensal species in therapy-naive pediatric CD patients (n=103) and controls (n=61). IgG responses were related to immunological and clinicopathological parameters. Results CD patients had significantly higher IgG responses to 12/19 Lachnospiraceae-derived flagellins compared to controls. Multi-reactivity to more than 10 flagellins was common in CD (41%) and associated with increased circulating flagellin-specific memory CD4+ T-cell frequencies. Multi-reactivity, and even single-reactivity to recombinant flagellin, correlated with reduced immune cell infiltration and epithelial damage, and fewer calprotectin-positive neutrophils in colonic lesional tissue, based on histological severity scoring and immune histochemistry, respectively. As these data may argue that high anti-flagellin IgG reactivity relates to innate hyporesponsiveness, we next assessed whether patients had a generalized high IgG response to lysates of dysbiotic intestinal bacteria. Hierarchical clustering identified subgroups of CD patients with different patterns of significantly increased anti-commensal IgG responses. Patients with high anti-Lachnospiraceae flagellin IgG also had high IgG responses against lysate of Roseburia inulinivorans, a Lachnospiraceae species. Of these anti-flagellin high responders, two-thirds responded to many commensals while one-third did not, arguing against a generalized high anti-commensal IgG response. Conclusion In conclusion, high IgG responses to Lachnospiraceae-derived flagellins identify a subgroup of pediatric therapy-naive CD patients with features of innate hyporesponsiveness. These patients do not have uniformly high IgG responses to other dysbiotic commensals, arguing that disturbed host-microbiota responses in CD are highly personalized and do not stem from an overall failure in microbiota-host crosstalk.

The necessity of validity diagnostics when drawing causal inferences from observational data: lessons from a multi-database evaluation of the risk of non-infectious uveitis among patients exposed to Remicade®

BackgroundAutoimmune disorders have primary manifestations such as joint pain and bowel inflammation but can also have secondary manifestations such as non-infectious uveitis (NIU). A regulatory health authority raised concerns after receiving spontaneous reports for NIU following exposure to Remicade®, a biologic therapy with multiple indications for which alternative therapies are available. In assessment of this clinical question, we applied validity diagnostics to support observational data causal inferences.MethodsWe assessed the risk of NIU among patients exposed to Remicade® compared to alternative biologics. Five databases, four study populations, and four analysis methodologies were used to estimate 80 potential treatment effects, with 20 pre-specified as primary. The study populations included inflammatory bowel conditions Crohn’s disease or ulcerative colitis (IBD), ankylosing spondylitis (AS), psoriatic conditions plaque psoriasis or psoriatic arthritis (PsO/PsA), and rheumatoid arthritis (RA). We conducted four analysis strategies intended to address limitations of causal estimation using observational data and applied four diagnostics with pre-specified quantitative rules to evaluate threats to validity from observed and unobserved confounding. We also qualitatively assessed post-propensity score matching representativeness, and bias susceptibility from outcome misclassification. We fit Cox proportional-hazards models, conditioned on propensity score-matched sets, to estimate the on-treatment risk of NIU among Remicade® initiators versus alternatives. Estimates from analyses that passed four validity tests were assessed.ResultsOf the 80 total analyses and the 20 analyses pre-specified as primary, 24% and 20% passed diagnostics, respectively. Among patients with IBD, we observed no evidence of increased risk for NIU relative to other similarly indicated biologics (pooled hazard ratio [HR] 0.75, 95% confidence interval [CI] 0.38–1.40). For patients with RA, we observed no increased risk relative to similarly indicated biologics, although results were imprecise (HR: 1.23, 95% CI 0.14–10.47).ConclusionsWe applied validity diagnostics on a heterogenous, observational setting to answer a specific research question. The results indicated that safety effect estimates from many analyses would be inappropriate to interpret as causal, given the data available and methods employed. Validity diagnostics should always be used to determine if the design and analysis are of sufficient quality to support causal inferences. The clinical implications of our findings on IBD suggests that, if an increased risk exists, it is unlikely to be greater than 40% given the 1.40 upper bound of the pooled HR confidence interval.

Intestinal Ultrasound Measures are Strongly Correlated With Small Bowel Endoscopic Lewis Score in Active Crohn's Disease.

Small bowel video capsule endoscopy (SB-VCE) assesses mucosal inflammation in Crohn's disease (CD), while intestinal ultrasound (IUS) examines transmural involvement. We aimed to correlate SB-VCE with IUS in evaluating active CD and monitoring treatment response over time. Patients with active SB-CD who initiated biologics were prospectively followed with fecal calprotectin (FC), SB-VCE, and IUS at baseline and after 14 and 52 weeks. The Lewis score (LS), Limberg index (LI), and terminal ileum bowel wall thickness (TI-BWT) were documented, and the International Bowel Ultrasound Segmental Activity Score (IBUS-SAS) was retrospectively calculated. Biochemical, endoscopic, and ultrasonographic remission were defined as FC < 150 μg/g, LS < 135, and LI < 2 + TI-BWT ≤ 3mm, respectively. A therapeutic response for each index was defined as a 25% reduction compared to baseline. Seventy-one patients were included (median age: 30 years [23-43], 49.3% male). The median interval between SB-VCE and IUS was 3 days (0-25). Initially, the LS strongly correlated with TI-BWT (r = 0.647, P < .001), LI (r = 0.597, P < .001), and IBUS-SAS (r = 0.647, P < .001), but these correlations weakened over time (TI-BWT: r = 0.344, P = .002; LI: r = 0.471, P = .001; IBUS-SAS: r = 0.236, P = .122). Moderate agreement was found between ultrasonographic and endoscopic treatment responses (LS and TI-BWT: K = 0.51, P = .015; LS and LI: K = 0.44, P = .063), with fair agreement for remission (K = 0.27, P = .006). TI-BWT best cutoffs for mild (LS ≥ 135) and moderate-to-severe (LS ≥ 790) inflammation were 2.25mm and 3.6mm, respectively. IUS measures are strongly correlated with VCE-inflammatory LS in active CD and may provide an assessment of endoscopic response and remission over time.

Improvement of Transmural Inflammation With Adalimumab Versus Immunomodulator Maintenance Therapy in Pediatric Crohn's Disease: Single-Center Prospective Evaluation Using the Pediatric Inflammatory Crohn's Magnetic Resonance Enterography Index.

Transmural healing, including as assessed by magnetic resonance enterography (MRE) has been associated with long-term favorable outcomes in Crohn's Disease (CD), but data concerning MRE improvement and normalization with therapy are sparse. We performed a prospective longitudinal study utilizing the recently developed pediatric MRE-based multi-item measure of inflammation (PICMI) to examine the efficacy of adalimumab (ADA) and immunomodulator (IM) in attaining improvement of transmural inflammation of the small intestine. Pediatric patients with CD involving small bowel and initiating ADA or IM were prospectively enrolled and followed with repeat MRE at 1 year. A single radiologist provided global assessment (RGA) and scored PICMI items (wall thickness, wall diffusion restriction, mural ulcers, comb sign, mesenteric edema) blinded to clinical information and to the timing of MRE. The primary outcome was mild improvement in PICMI at one year without a change in therapy. Sixty-two eligible patients were enrolled, 26 receiving ADA and 36 IM. On intent to treat basis, a decline in PICMI score of >20 points without change of therapy was observed more frequently in ADA versus IM-treated patients (54% vs 31%, P = .01). By RGA, 71% improved with ADA vs 42% with IM (P = .03). MRE normalization was rare with both treatments (9% vs 6%, P = .62). A change in PICMI of >20 points was confirmed as the best cut off for MRE improvement as assessed by RGA also for the small bowel. ADA therapy was associated with objective improvement in MRE findings of inflammation more frequently than IM. The low rate of MRE normalization suggests that this is not yet a realistic target with existing therapies.

Leucine-Rich Alpha-2 Glycoprotein Is Associated With Transmural Inflammation Assessed by Intestinal Ultrasound in Patients With Crohn's Disease.

Intestinal ultrasound (IUS) is a non-invasive tool for evaluating transmural inflammation in Crohn's disease (CD). However, its utility is constrained by operator dependency and limited accessibility. To explore the feasibility of serum biomarkers-specifically leucine-rich alpha-2 glycoprotein (LRG)-as an alternative to IUS for assessing transmural inflammation. This retrospective, single-centre study included patients with CD who underwent IUS and measurements of LRG and C-reactive protein (CRP). We assessed correlations between biomarkers and five IUS scores (Limberg score, Bowel Ultrasound Score (BUSS), International Bowel Ultrasound Segmental Activity Score (IBUS-SAS), Simple Ultrasound Score (Simple-US) and Simple Ultrasound Score for Crohn's Disease (SUS-CD)) using receiver operator characteristic curve analysis and Spearman's rank correlation coefficient. We conducted subgroup analyses for patients in clinical remission. We analysed 213 IUS examinations performed on 97 patients; 170 (80%) IUS were during clinical remission. The area under the curve for LRG for each IUS score (0.76, 0.80, 0.77, 0.75 and 0.69, respectively) was superior to that of CRP and was statistically significant, particularly for LS, BUSS, IBUS-SAS and Simple-US (p < 0.001, p = 0.018, p < 0.001 and p < 0.001, respectively). Predictive values remained consistent among patients in remission. LRG demonstrated excellent correlation with IUS scores in both the overall patient population and those in remission. LRG showed a robust correlation with IUS scores, suggesting its potential as a novel indicator for targeting transmural healing in patients with CD.

Prevalence and Prognosis of Mild Inflammatory Bowel Disease: A Population-based Cohort Study, 1997-2020.

The inflammatory bowel diseases (IBDs), ulcerative colitis (UC) and Crohn's disease (CD), are heterogenous diseases ranging from mild to severe. We aimed to describe the prevalence and prognosis of mild IBD in an unselected population-based patient cohort. We identified all individuals diagnosed with IBD during 1997 to 2020 in North Denmark (n=4607). Patients with mild disease, based on treatment history within the first year, were followed for progression to moderate-severe disease, based on a composite outcome of immunomodulators, biologic therapies, IBD-related hospitalization, and/or surgery. We used time-to-event analysis to calculate probabilities of progression based on IBD subtype, age, sex, and duration of mild IBD. Among 2315 individuals with initial mild IBD, 24.5% with UC (n= 474) and 46% with CD (n=174) progressed to moderate-severe disease during follow-up. Of the total IBD population, 52.3% of patients with UC and 86.8% with CD progressed during follow-up. Individuals <18years at diagnosis were the most likely to progress. The 10-year probability of progressing to moderate-severe UC was 26% after 1 year with mild disease, 19% after 5 years, and 12% after 10 years. The probability of progressing to moderate-severe CD was 53% after 1 year with mild disease, 34% after 5 years, and 33% after 10 years. Approximately one-fourth of individuals with mild UC within 1 year after diagnosis and one-half of those with mild CD progressed to moderate-severe disease over time. Young age at diagnosis increased the probability of progression, whereas increasing duration of mild disease decreased the probability.

Prognostic value of magnetic resonance enterography for children with Crohn's disease: A multicenter, multireader study

BackgroundPaediatric Inflammatory Crohn's MRE Index (PICMI) is a multi-point index of intestinal inflammation (mucosal and transmural) for children with CD. The present study aims to assess whether PICMI at diagnosis may predict the course of CD and to test the inter-reader agreement. MethodsCD children with a ≥ 1-year follow-up were retrospectively enrolled. Three radiologists calculated PICMI at diagnosis and association between PICMI and Paediatric Crohn's Disease Activity Index (PCDAI) and CD Endoscopic Index of Severity (CDEIS) was tested. Results68 children (median age 13 years IQR: 11–14) with CD with PICMI at diagnosis: remission 6 (8.8 %), mild 29 (42.6 %), moderate 24 (35.3 %), severe 9 (13.2 %), were enrolled. PICMI score significantly correlated with PCDAI at diagnosis (p: 0.036). Steroid-free remission at 1, 3 and 5 years was comparable between PICMI groups (p: 0.606). Higher PICMI at diagnosis was associated with higher biologic introduction at 1 year: incidence rate ratio IRR: 2.17 (1.09–4.42); p = 0.019, 3-year IRR: 2.12 (1.15–3.96); p = 0.011, and 5 years: 2.21 (1.20–4.08); p = 0.007. ConclusionsPICMI score is a reliable and almost reproducible index to score activity in children with CD. Children with higher PICMI scores of disease activity at diagnosis required more biologic treatment to achieve comparable rates of steroid-free remission if compared with lower PICMI scores.

Inflammatory bowel disease and risk of ophthalmic inflammation-related diseases: a two-sample Mendelian randomization study.

To investigate the causal effect of inflammatory bowel disease (IBD) on ocular inflammation using Mendelian randomization (MR) analysis. Genetic instruments associated with inflammatory bowel disease (IBD), ulcerative colitis (UC), and Crohn's disease (CD) were derived from the largest genome-wide association studies (GWAS) published to date. The FinnGen research project was utilized to identify genetic risk variants associated with conjunctivitis, keratitis, iridocyclitis, chorioretinitis, episcleritis, and optic neuritis. All participants were of European ancestry. Three methods which included inverse variance weighting (IVW), weighted median (WM), and MR-Egger regression were performed to estimate the causal association in this study. IVW took the inverse variance of each study as the weight to calculate the weighted average of effect sizes, to summarize the effect sizes of multiple independent studies, which could provide the most precise estimated results. IVW was used as the primary outcome, while WM and MR-Egger were used to improve the estimation of IVW. A nominal causal effect of genetically predicted IBD on risk of non-infectious conjunctivitis, keratitis, iridocyclitis, and optic neuritis, but not on chorioretinitis or episcleritis. After Bonferroni correction, the results showed that genetically predicted UC was significantly associated with an increased risk of iridocyclitis (IVW: OR, 1.17; 95%CI, 1.10-1.24, P=2.54×10-7). CD was significantly associated with conjunctivitis (IVW: OR, 1.05; 95%CI, 1.03-1.08, P=3.20×10-5), keratitis (IVW: OR, 1.06; 95%CI, 1.02-1.09; P=1.13×10-3), and iridocyclitis (IVW: OR, 1.09; 95%CI, 1.04-1.14; P=1.43×10-4). IBD causally poses a risk of inflammation of conjunctiva, cornea, Iris-ciliary body complex, and optic neuritis. CD is more closely associated with the eye inflammation than UC. These impliy that the relationship of IBD and different parts of the eye structure are different, and provide novel evidence linking based on the association of the gut-eye axis.

Pro-inflammatory NK-like T cells are expanded in the blood and inflamed intestine in Crohn’s disease

Altered intestinal immune homeostasis leads to chronic inflammation in Crohn’s disease (CD). To address disease- and tissue-specific alterations, we performed a T cell-centric mass cytometry analysis of peripheral and intestinal lymphocytes from patients with CD and healthy donors’ PBMCs. Chronic intestinal inflammation enforced activation, exhaustion, and terminal differentiation of CD4+ and CD8+ T cells and a relative enrichment of CD4+ regulatory T (Treg) cells. Moreover, enigmatic rare Treg subsets appeared upon inflammation, e.g. CD4+FOXP3+HLA-DR+TIGIT– and CD4+FOXP3+CD56+, expressing pro-inflammatory IFN-γ upon in vitro stimulation. Some conventional T (Tcon) cells acquired NK-like features. In CD patients’ blood, not well studied CD16+CCR6+CD127+ T cells appeared, being CD4+ or CD8+, a phenotype inducible on healthy T cells by CD blood plasma. Upon CD16-mediated antibody binding, they could attain effector function. These findings suggest an uncommon pro-inflammatory innate-like differentiation of Treg and Tcon cells with acquisition of non-specific cytotoxicity. Most likely, this is both cause and consequence of intestinal inflammation during CD.

Gut Microbial Signatures in Pediatric Crohn's Disease Vary According to Disease Activity Measures and Are Influenced by Proxies of Gastrointestinal Transit Time: An ImageKids Study.

We investigated relationships between disease activity measures and the gut microbiome in children with Crohn's disease (CD) and how these were confounded by gastrointestinal transit time. Microbiome was profiled (16S rRNA sequencing) in feces from 196 children with CD. Sixty participants also provided samples after 18 months. Mural inflammation (Pediatric Inflammatory Crohn's Magnetic Resonance Enterography Index, PICMI), the simple endoscopic score for CD, and the weighted pediatric Crohn's disease activity index (wPCDAI) were assessed. Fecal calprotectin, plasma C-reactive protein (CRP), and fecal water content (FWC), a proxy of gastrointestinal transit time, were measured too. Microbiome α diversity, clustering, and differential taxa were related to disease status, but varied remarkably by disease activity measure used. The strongest relationships between microbiome and disease activity status were observed using wPCDAI; fewer or no relationships were seen using more objective measures like PICMI. Taxa predictive of disease activity status were dependent on the disease activity measure used with negligible overlap. Active disease was associated with more pathobionts (eg, Viellonella, Enterobacterales) and fewer fiber-fermenting organisms. The effect FWC had on microbiome superseded the effect of active disease for all disease activity measures, particularly with wPCDAI. Accounting for FWC, the differences in microbial signatures explained by disease activity status were attenuated or lost. In CD, microbiome signatures fluctuate depending on the measure used to assess disease severity; several of these signals might be secondary disease effects linked with changes in gut motility in active disease. PICMI appears to be less influenced when studying relationships between microbiome and mural inflammation in CD.

Germline polygenic risk scores are associated with immune gene expression signature and immune cell infiltration in breast cancer

The tumor immune microenvironment (TIME) plays key roles in tumor progression and response to immunotherapy. Previous studies have identified individual germline variants associated with differences in TIME. Here, we hypothesize that common variants associated with breast cancer risk or cancer-related traits, represented by polygenic risk scores (PRSs), may jointly influence immune features in TIME. We derived 154 immune traits from bulk gene expression profiles of 764 breast tumors and 598 adjacent normal tissue samples from 825 individuals with breast cancer in the Nurses' Health Study (NHS) and NHSII. Immunohistochemical staining of four immune cell markers were available for a subset of 205 individuals. Germline PRSs were calculated for 16 different traits including breast cancer, autoimmune diseases, type 2 diabetes, ages at menarche and menopause, body mass index (BMI), BMI-adjusted waist-to-hip ratio, alcohol intake, and tobacco smoking. Overall, we identified 44 associations between germline PRSs and immune traits at false discovery rate q<0.25, including 3 associations with q<0.05. We observed consistent inverse associations of inflammatory bowel disease (IBD) and Crohn disease (CD) PRSs with interferon signaling and STAT1 scores in breast tumor and adjacent normal tissue; these associations were replicated in a Norwegian cohort. Inverse associations were also consistently observed for IBD PRS and B cell abundance in normal tissue. We also observed positive associations between CD PRS and endothelial cell abundance in tumor. Our findings suggest that the genetic mechanisms that influence immune-related diseases are also associated with TIME in breast cancer.

Utilizing pigs as a model for studying intestinal barrier function

Abstract Intestinal permeability has been extensively studied, particularly in gastrointestinal diseases such as inflammatory bowel disease, food allergy, visceral disease, celiac disease, and Crohn’s disease. These studies have established that changes in intestinal permeability contribute to the pathogenesis of many gastrointestinal and systemic diseases. While numerous works in the 20th century focused on this topic, it remains relevant for several reasons. Despite the development of new research techniques, it is still unclear whether changes in intestinal permeability are the primary mechanism initiating the disease process or if they occur secondary to an ongoing chronic inflammatory process. Investigating the possibility of stabilizing the intestinal barrier, thereby reducing its permeability preemptively to prevent damage and after the damage has occurred, may offer new therapeutic approaches. Increased intestinal permeability is believed to lead to reduced nutrient absorption, resulting in decreased immunity and production of digestive enzymes.

Identifying the importance of PCK1 in maintaining ileal epithelial barrier integrity in Crohn’s disease

BackgroundCrohn’s disease (CD) is marked by disruption of intestinal epithelial barrier, with unclear underlying molecular mechanisms. This study aimed to investigate key genes regulating the intestinal barrier in CD patients. MethodsDifferential gene expression analysis and gene set enrichment analysis were conducted to identify potential key genes involved in CD within the GEO database. Single-cell RNA sequencing from ileum samples in GSE134809 of 59,831 inflamed and uninflamed cells from 11 CD patients and microarray data from ileal tissues in GSE69762 (3 controls and 4 CD patients) and GSE75214 (11 controls and 51 CD patients) with GSE179285 (49 uninflamed and 33 inflamed from CD patients) as the validation set. Protein-protein interaction and logistic regression analyses identified key downregulated genes in CD. A key gene was then investigated through immunohistochemistry of ileal tissues from 5 CD patients and in the Caco-2 cell line with RNA interference and treatment with IFN-γ and TNF-α to stimulate inflammation. ResultsSingle-cell RNA-seq identified 33 genes and microarray identified 167 genes with significant downregulation in inflamed CD samples. PCK1 was identified and validated as one of the most promising candidate genes. Reduced PCK1 expression was evident in inflamed ileal tissues. In vitro, knockdown of PCK1 resulted in decreased cell viability, increased apoptosis, and reduced nectin-2 production, while combination of IFN-γ and TNF-α significantly reduced PCK1. ConclusionsPCK1 is downregulated in inflamed ileal tissues of CD patients and may be a key factor in maintaining epithelial integrity during inflammation in Crohn’s disease.

Contribution of the Gut Microbiome to the Perpetuation of Inflammation in Crohn's Disease: A Systematic Review.

Crohn's disease (CD) is a sub-type of inflammatory bowel disease (IBD) with a characteristic relapsing and remitting inflammation involving the gastrointestinal (GI) tract. Although there are several medications to relieve the symptoms, there is no definite cure for the condition. This paper highlights how CD affects our gut flora, which subsequently leads to the perpetuation of inflammation. This review was conducted according to Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) 2020 guidelines using PubMed, ScienceDirect,Multidisciplinary Digital Publishing Institute (MDPI), and Google Scholar as sources for relevant literature. After applying the quality appraisal tools, we finalized 11 articles for the paper. Inflammation seen in CD leads to dysbiosis, where there is a reduction in beneficial microbes such as Faecalibacterium and Roseburia species and an increase in pathogenic microbes such as Escherichia and Proteus species. This difference in gut microbes disrupts barrier function and immune processes in the intestine, contributing to the worsening of inflammation seen in CD. Several studies have been carried out to understand this complex relationship between the gut microbiome (GM) and CD, as it may serve as a potential novel therapeutic alternative, necessary as CD's burden is increasing globally.

Inhibition of Transmural Inflammation in Crohn's Disease by Orally Administered Tumor Necrosis Factor-Alpha Deoxyribozymes-Loaded Pyroptosis Nanoinhibitors.

Crohn's disease (CD) is a refractory chronic inflammatory bowel disease (IBD) with unknown etiology. Transmural inflammation, involving the intestine and mesentery, represents a characteristic pathological feature of CD and serves as a critical contributor to its intractability. Here, this study describes an oral pyroptosis nanoinhibitor loaded with tumor necrosis factor-α (TNF-α) deoxyribozymes (DNAzymes) (DNAzymes@degradable silicon nanoparticles@Mannose, Dz@MDSN), which can target macrophages at the site of inflammation and respond to reactive oxygen species (ROS) to release drugs. Dz@MDSN can not only break the inflammatory cycle in macrophages by degrading TNF-α mRNA but also reduce the production of ROS mainly from macrophages. Moreover, Dz@MDSN inhibits excessive pyroptosis in epithelial cells through ROS clearance, thereby repairing the intestinal barrier and reducing the translocation of intestinal bacteria to the mesentery. Consequently, these combined actions synergistically contribute to the suppression of inflammation within both the intestine and the mesentery. This study likely represents the first successful attempt in the field of utilizing nanomaterials to achieve transmural healing for CD, which also provides a promising treatment strategy for CD patients.

A Rapid and Reliable Spectrofluorimetric Method to Measure the Urinary Lactulose/Mannitol Ratio for Dysbiosis Assessment.

Gut microbiota plays a crucial role in human health homeostasis, and the result of its alteration, known as dysbiosis, leads to several pathologies (e.g., inflammatory bowel disease, metabolic syndrome, and Crohn's disease). Traditional methods used to assess dysbiosis include the dual sugar absorption test and the urinary lactulose/mannitol ratio (LMR) measurement using mass spectrometry. Despite its precision, this approach is costly and requires specialized equipment. Hence, we developed a rapid and reliable spectrofluorimetric method for measuring LMR in urine, offering a more accessible alternative. This spectrofluorimetric assay quantifies the fluorescence of nicotinamide adenine dinucleotide (NADH) and nicotinamide adenine dinucleotide phosphate (NADPH) produced during the enzymatic oxidation of mannitol and lactulose, respectively. The assay requires 100 µL of urine samples and detects LMR values lower (eubiosis) and higher (dysbiosis) than 0.05, ultimately being amenable to high-throughput screening and automatization, making it practical for clinical and research settings. A validation of the method demonstrated its high precision, accuracy, and robustness. Additionally, this study confirmed analyte stability under various storage conditions, ensuring reliable results even with delayed analysis. Overall, this spectrofluorimetric technique reduces costs, time, and the environmental impact associated with traditional mass spectrometry methods, making it a viable option for widespread use in the assessment of dysbiosis.