Introduction

Vedolizumab (VDZ), an α4β7 integrin receptor antagonist monoclonal antibody, reduces inflammation and induces clinical remission in the treatment of Inflammatory Bowel Disease (IBD) patients with high efficacy and safety. The effect of this treatment on the gut microbiome and its relationship with clinical outcomes are still underexplored in IBD patients.

Aims & Methods

In this study, the effect of VDZ treatment on changes in gut microbiota composition of IBD patients was explored and correlated with clinical data and colonic epithelial barrier integrity.23 IBD patients undergoing VDZ treatment and 16 healthy controls (HC) were enrolled. Crohn's disease (CD) and ulcerative colitis (UC) patients were evaluated for clinical remission and response using the Harvey-Bradshaw Index (HBI) and the Partial Mayo Score (PMS), respectively, at three time points: before treatment (T0), after 24 weeks (T1), and after 52 weeks (T2). Clinical response to VDZ treatment was defined as a reduction in the Harvey-Bradshaw Index (HBI) score > 2 for CD and a decrease in the Partial Mayo Score (PMS) > 2 for UC, along with either a rectal bleeding subscore of ≥1 or a rectal bleeding subscore of 0 or 1. During each endoscopy, 8 colonic biopsies were collected for immunohistochemical analyses, permeability assessment using the Ussing Chambers system and for microbiota analysis via MiSeq 16S rRNA gene sequencing. Immunohistochemical analysis of integrin α4β7 and tight junction (TJ) complex system proteins was performed.

Results

A significant reduction in PMS (p<0.0001) and HBI (p<0.01) was observed in the IBD population at T2 compared to T0. A significant increase in Roseburia, Collinsella, Tidjanibacter, and a decrease in Enterocloster and Clostridium were observed in IBD patients at T2 compared to T0 in fecal microbiota. The mucosal microbiota of IBD patients at T2 demonstrated significant enrichment of Proteobacteria and Acidaminococcus compared to T0. When stratifying the IBD patients into clinical responders (RSPs) and non-clinical responders (nRSPs) at T2, an increase in Firmicutes, Actinobacteria, and Proteobacteria was observed in RSPs at T0 compared to nRSPs in the fecal microbiota, with an enrichment in Bifidobacterium highly associated with response to VDZ. Interestingly, a significant enrichment of Prevotella at T0 and of Akkermansia at T2 was found in the mucosal microbiota of RSPs. Finally, at T2, a negative correlation was identified between Clostridium and TEER values (p=0.0048) and between Ruminococcus and FD-4 permeability values (p=0.0001). Immunohistochemistry data showed an enhanced expression of integrin α4β7 at T0 compared to controls; a significant reduction was observed at T1 and T2. Concurrently, the expression of TJ complex system proteins was significantly reduced before treatment (T0) compared to controls, with a significant increase after 24 weeks; this increase was maintained following 52 weeks.

Conclusion

These findings suggest that VDZ, by reducing leukocyte trafficking and mucosal inflammation, may positively impact intestinal barrier integrity and address intestinal dysbiosis in IBD patients. Further studies are needed to identify specific biomarkers advancing the approach toward personalized medicine.

References

1. Lo Presti A, Zorzi F, Del Chierico F, Altomare A, Cocca S, Avola A, De Biasio F, et al. Fecal and Mucosal Microbiota Profiling in Irritable Bowel Syndrome and Inflammatory Bowel Disease. Front Microbiol. 2019
2. Cicala M, Gori M, Balestrieri P, et al. Colonic Epithelial Permeability to Ions Is Restored after Vedolizumab Treatment and May Predict Clinical Response in Inflammatory Bowel Disease Patients. Int J Mol Sci. 2024
3. Ananthakrishnan AN, Luo C, Yajnik V, et al. Gut microbiome function predicts response to anti-integrin biologic therapy in inflammatory bowel diseases. Cell Host Microbe 2017
4. Schneider I, Allner C, Mühl L, et al. Expression and function of α4β7 integrin predict the success of vedolizumab treatment in inflammatory bowel disease. Transl Res. 2023;253:8-15.

Introduction

PD-1 downregulates activated T cells and dysregulation of its signaling impacts critical T cell responses in inflammatory and autoimmune diseases, including ulcerative colitis (UC). In UC lamina propria, multiple T cell subtypes express PD-1, including peripheral helper T cells (Tph) and effector memory T cells, and the reduction of PD-1+ Tph cells is correlated with remission.¹ While PD-1 is being evaluated in UC, it has been clinically validated as a target in two Ph2 studies in RA.^2,3 Rosnilimab, an investigational antibody, aims to leverage immune homeostatic mechanisms to regulate T cell activity by depleting PD-1^high T cells and reducing the activity of remaining PD-1+ T cells.⁴ Rosnilimab, when compared to isotype control, reduced inflammation of the colon, reduced infiltration of CD4 T cells and maintained body weight of mice in a murine model of colitis induced by the transfer of CD4+CD45Rb+ T cells from human PD-1 transgenic mice.⁵ Additionally, pathway genes indicative of fibrosis and impaired barrier function in human UC were normalized in rosnilimab-treated animals while dysregulated in the control group.⁶ Myeloid cells also contribute to inflammation in human UC, and reduction of their elevated numbers are associated with disease remission.⁷ An inflammatory myeloid cell gene signature was derived from human UC and used to assess inflammatory myeloid cells and the therapeutic impact of rosnilimab in this murine model of colitis.

Aims & Methods

A UC myeloid gene signature was derived via secondary analyses of single-cell RNA sequencing data from a published atlas of human UC tissue⁷ to identify 1,652 genes that were upregulated in inflamed myeloid cells compared to non-inflamed cells. These genes were then compared with 3,859 genes upregulated in a murine model of colitis. The resultant overlap of 625 genes was used to define the mouse colitis myeloid gene signature. Overlapping genes were analyzed for regulation in the murine model of colitis following rosnilimab treatment. Myeloid cell gene transcription in colonic tissue from mice treated with rosnilimab or isotype control was assessed via spatial transcriptomics.

Results

In a murine model of colitis, rosnilimab treatment resulted in the downregulation of 399 (64%) of the mouse colitis myeloid signature genes, suggesting an ability to impact a large proportion of the overlapping genes that are similarly dysregulated in human UC. These included mediators of immune cell recruitment (Ccl3, Ccr1) and detection of bacterial components (Cd14, Tlr2 and Tlr4). Additionally, genes involved in immune activation and amplification mediated by myeloid cells were reduced by rosnilimab (Il6, Cd80, Cd86, Myd88, Trem1, and Stat4). Spatial transcriptomic analyses of colonic tissue showed that rosnilimab reduced myeloid cell numbers, including M1 and M2 macrophage subtypes, compared to isotype control treated mice.

Conclusion

In addition to reducing pathogenic T cell numbers in this murine model of colitis, rosnilimab treatment also reduced pathogenic macrophages and the inflammatory myeloid gene signature in the colon. These data support previous preclinical findings demonstrating the potential therapeutic benefits of selectively targeting activated PD-1+ T cells and depleting PD-1^high T cells in reducing inflammation and improving UC outcomes in a murine model of colitis. These results, together with existing rosnilimab safety data in humans, support the scientific rationale for evaluating rosnilimab in an ongoing Phase 2 study in UC (NCT06127043).

References

1. Long Y, et al. Immunol Letters 2021;233:2-10.
2. AnaptysBio press release February 12, 2025. Ir.anaptsbio.com/news-release-details.
3. Tuttle J, et al. N Engl J Med 2023;388:1853-62.
4. Luu K, et al. J Crohn’s Colitis 2024;18(S1):i225 (Abstract DOP81).
5. Parmley S, et al. United Eur Gastroenterol J 2024;12:482 (Abstract MP448).
6. Linggi B, et al. J Crohn’s Colitis 2025;19(S1):i475 (Abstract P0101).
7. Thomas T, et al. Nature Immunol 2024;25:2152-65.

Disclosure

All authors are employees and shareholders of AnaptysBio

Introduction

Inflammatory Bowel Diseases (IBD) are chronic immune-mediated disorders of the gastrointestinal tract. Fibrosis is a frequent manifestation in IBD driven by inflammatory cytokines. During fibrosis, extracellular matrix proteins accumulate in the tissue, causing the disruption of the epithelial barrier and stenosis, ultimately causing malabsorption and intestinal motility issues. This can eventually lead to further serious complications, strictures, fistulas, or ileus. No drugs are available targeting fibrosis, in these cases, only surgical intervention can be used. A defined primary in vitro cell culture model is not available for intestinal fibrosis modeling.

Aims & Methods

Therefore, we aimed to establish and characterize human primary fibroblast cell culture from intestinal biopsies of control and IBD patients.
Human primary fibroblast cell cultures were generated from colonic biopsy of patients with IBD (N=4) and control (N=4). All downstream analyses were applied in passage number 3. For the phenotype observation, immunofluorescent staining was used. Targeted proteins were COL1A1, TGF-ß1, PAI-1, α-SMA, and PHH3. Proteome Profiler Human Cytokine Array Kit was used for the secreted cytokine pattern observation. For the gene expression analysis, RNA was isolated, and the qRT-PCR technique was utilized for the following target genes: COL1A1, ACTA2, TGF-ß1, FN1, PAI-1, H3C4. Scratch assay was used to examine wound closure, we monitored the closing for 48 hours taking photographs throughout. We evaluated the collected data and performed statistical analysis.

Results

We can successfully generate and maintain human colon primary fibroblast cell cultures from colonic biopsies of healthy and Crohn’s disease (CD) origins. Morphological differences were observed between control and diseased patient samples. In the protein examinations, the fluorescent intensity of fibrotic markers (COL1A1, TGF-ß1, PAI-1) and the mitosis marker PHH3 were significantly higher in the CD samples, indicating that the cells maintained fibrotic phenotype and the diseased fibroblasts had a higher proliferation rate. The myofibroblast marker, α-SMA, didn’t show a significant difference. In the cytokine pattern analysis, 22 cytokines showed a twofold increase or decreased by half between the two groups. HGF and DPPIV showed higher quantities in the CD-originated fibroblast. These cytokines are connected to the induction of fibrosis. However, the ANG, BDNF, PTX-3, VEGF, and VCAM-1 were higher in the control samples. Interestingly, no significant differences were noted between the two groups in the targeted genes examined by qRT-PCR measurements. We observed the closure of the artificial wound was faster and more effective in the Crohn’s disease culture compared to the control.

Conclusion

In conclusion, we can generate primary human intestinal fibroblast cell cultures and maintain them to passage number 3, approximately a month long. Fibrotic markers, secreted cytokines and morphological differences distinguish the diseased cultures from the healthy subjects; therefore, it could be useful for in vitro fibrosis modeling in the future. On the other hand, the gene expression analysis doesn’t discriminate between the two groups at passage number 3. To continue with our work, we will observe the fibrotic properties in earlier passage numbers.

Introduction

Corticosteroids are a common treatment for patients with moderate to severe active ulcerative colitis (UC), but their effects can vary among individuals, including resistance, response, and dependence. While patient responses to corticosteroid therapy are generally swift, clinical remission may not be immediate for some. This suggests that corticosteroid treatment should be continued for a period of time to differentiate between corticosteroid-resistant and corticosteroid-sensitive patients with moderate to severe disease activity. Consequently, identifying factors that can predict whether steroid use should be maintained or if a switch to a different treatment is necessary is an important consideration.

Aims & Methods

We compared the clinical characteristics of steroid responders and non-responders in patients with UC and retrospectively evaluated for biomarkers that could predict the efficacy of corticosteroid therapy prior to treatment in patients with moderate to severe active UC. Additionally, we compared the changes in various parameters before and after corticosteroid administration between steroid responders and non-responders. We enrolled 102 UC patients from Nippon Medical School Hospital who had a history of corticosteroid treatment prior to June 2024. The patients were divided into two groups: steroid responders and steroid non-responders. Their clinical characteristics were determined based on medical records.

Results

A total 102 UC patients with moderate to severe disease activity were included in this study. The clinical characteristics at baseline were as follows: the median age, 43 years (average 44.76± 17.79); with 61 males and 41 females. The most common distribution of disease type was total colitis (65%), followed by left-sided colitis (32%), and proctitis (2%). 42.6% of patients had severe disease activity. After remission induction therapy, 16% of patients were steroid non-responders, while 84% were steroid responders. The average Mayo Endoscopic Score was significantly lower, and eosinophil counts were higher in the steroid responder group compared to the steroid non-responder group (P=0.023, 0.016). We also compared changes in various parameters at baseline and 4 weeks after steroid treatment between the two groups. After 4 weeks, inflammation markers including CRP and platelet counts decreased significantly in both groups. Hemoglobin and albumin levels increased significantly, and eosinophil counts decreased in the steroid responder group, but these changes were not observed in the steroid non-responder group.
Histological examination revealed no significant difference in the number of eosinophils infiltrating the colorectal mucosa on biopsy before steroid therapy between the two groups. However, 4 weeks after treatment, the number of infiltrating eosinophils was significantly decreased in the steroid responder group (P<0.001, Wilcoxon signed-rank test), while no change was observed in the steroid non-responder group.

Conclusion

Eosinophil count in the blood could serve as a potential biomarker for steroid responsiveness prior to administration. Additionally, steroid use decreases inflammatory markers such as CRP and platelet count, regardless of patient response. However, eosinophil counts were reduced only in the responder group, suggesting that changes in eosinophil count may also be a predictor of efficacy in the long term.

Introduction

The Mayo Endoscopic Subscore (MES) is widely used in clinical trials and daily practice to assess disease activity and response to treatment in UC.

Aims & Methods

The objective of this study was to identify any nuances in patients with MES > 1 treated with non-TNF biologics and targeted oral therapies. The Ipsos UC Therapy Monitor, a multi-centre online medical chart review study of patients with UC, was conducted between July and September 2024 among gastroenterologists practicing across hospital and private practices in the UK, France, Germany, Italy, and Spain. Physicians were screened for practice duration and patient volume. Charts of patients prescribed advanced therapy were included in the analysis.

Results

205 sampled physicians collectively reported 820 UC patients. Of the reported patients with MES > 1, 62 were treated with non-TNF biologics and 62 were treated with novel oral therapies. Among the patients treated with non-TNF biologics, a higher proportion were female vs those receiving oral therapy (48% vs 31%); they were also older in age (mean years: 43 vs 38).
The patients treated with non-TNF biologics had a higher prevalence of comorbidities, including depression/anxiety (24% vs 19%), cardiovascular disease (8% vs 0%), and dyslipidemia/hyperlipidemia/hypercholesterolemia (11% vs 7%), compared to those treated with novel oral therapy.
Mean CRP levels were higher in the oral therapy group (10.2 mg/L vs 9.1 mg/L), while mean Mayo scores were slightly lower (4.7 vs 5.2). Fecal calprotectin levels were elevated in patients treated with non-TNF biologics vs oral therapy group (441 µg/g vs 503 µg/g).
When analysing reasons for prescribing selected advanced therapy between the two patient groups, a greater proportion of patients treated with non-TNF biologics had safety reasons specified more frequently by the sampled physicians.

Table 1: % of reported UC patients receiving advanced therapy for specific cited reasons

Conclusion

This study highlights key differences in patient characteristics and treatment considerations among UC patients with MES > 1 treated with non-TNF biologics compared to those treated with targeted oral therapies. Patients on non-TNF biologics tend to be older, more often female, and have a higher prevalence of comorbidities. Physicians prescribing non-TNF biologics prioritize safety, while those prescribing oral therapies focus on rapid symptom control. These findings highlight the importance of considering patient characteristics and treatment goals when selecting advanced therapies for UC patients with MES > 1. Further investigation using comparator cohort is warranted.

Introduction

The pathogenesis of ulcerative colitis (UC) involves complex immune responses, including Th1, Th2, and Th17 pathways, and is characterized by substantial heterogeneity. Cytokine profiling may contribute to understanding individual disease mechanisms and guiding personalized therapeutic strategies; however, its clinical application remains limited due to technical complexity. This study aimed to investigate whether endocytoscopic and histopathological findings correlate with mucosal cytokine expression levels and could serve as surrogate markers.

Aims & Methods

Thirty-five patients with UC receiving treatment at our institution were enrolled. Endocytoscopy (ultra-magnifying endoscopy) was performed in all patients, and the findings were classified according to the Endocytoscopic Classification system (EC classification: EC-A, EC-B, EC-C, EC-D). Mucosal biopsies were obtained from the most inflamed areas identified during endocytoscopy. Histological evaluation included the Matts histological grade and assessments of neutrophil, eosinophil, and lymphocyte infiltration; goblet cell depletion; crypt distortion; and epithelial damage, each graded on a four-point scale (absent, mild, moderate, severe). mRNA expression levels of cytokines (IFN-γ, TGF-β1, TNF-α, IL-1β, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12, IL-13, IL-17, and IL-23) were quantified using RT-PCR. Statistical analyses were performed to assess correlations between endocytoscopic/histopathological findings and cytokine expression levels.

Results

The median age of participants was 44 years (IQR: 35–57), with 24 males and 11 females. Disease types included pancolitis (n = 16), left-sided colitis (n = 14), and proctitis (n = 5). The median Mayo score was 1 (IQR: 0–5). EC classification scores showed significant positive correlations with the expression levels of IL-1β, IL-6, IL-8, IL-13, IL-17, and IL-23 (Spearman’s rank correlation, p < 0.05; r = 0.555, 0.526, 0.584, 0.441, 0.422, and 0.449, respectively). Similarly, Matts histological grades were significantly correlated with the expression of IFN-γ, IL-1β, IL-6, IL-8, IL-13, IL-17, and IL-23 (p < 0.05; r = 0.493, 0.756, 0.692, 0.730, 0.656, 0.623, and 0.448, respectively). Histopathological features—including neutrophil and lymphocyte infiltration, goblet cell depletion, epithelial damage, and crypt distortion—were significantly associated with the expression of IFN-γ, IL-1β, IL-6, IL-8, IL-13, IL-17, and IL-23. Additionally, eosinophil infiltration was positively correlated with the expression levels of IL-1β, IL-5, and IL-13.

Conclusion

This study demonstrates that endocytoscopic and histopathological indicators of inflammation are associated with mucosal expression levels of several cytokines—particularly inflammatory and Th17-related cytokines—in patients with ulcerative colitis (UC). These findings suggest that such evaluations may serve as surrogate markers, potentially improving disease assessment and informing therapeutic decision-making.

Introduction

The Mayo Endoscopic Subscore (MES) is the most widely used endoscopic index for assessing disease activity in ulcerative colitis (UC). Although artificial-intelligence　(AI)–assisted colonoscopy is expected to reduce inter-observer variability, the MES 4-point scale (0–3) lacks sufficient sensitivity to detect subtle changes in mucosal activity, limiting its ability to capture incremental improvement or deterioration. Moreover, because MES focuses on qualitative features—such as bleeding and erosions—without considering the extent or surface area of inflammation, it provides an incomplete estimate of a patient’s overall inflammatory burden.

Aims & Methods

We sought to develop and validate a quantitative, AI–driven colonoscopic score—Quantitative Ulcerative Colitis Assessment using Deep-learning (QUAD)—and to determine whether it predicts clinical relapse in patients with UC. The QUAD system was trained on 84 743 colonoscopic images from 998 UC patients at three centers and comprises three main functions: i) Image filtering: Automatic exclusion of low-quality images that are unsuitable for analysis owing to light saturation (halation), inadequate insufflation, excessive proximity to the mucosa, chromoendoscopy, or virtual chromoendoscopy. ii) Frame-level scoring: Each frame is divided into four quadrants; inflammation in each quadrant is graded from 0 to 3, and the quadrant scores are summed to yield a QUAD score of 0–12. iii) Video-level aggregation: Full-length withdrawal videos are processed to generate (i) an Entire QUAD score (0–60), representing pan-colonic inflammation, and (ii) a Distal QUAD score (0–12) for the rectosigmoid segment (final 20 % of the video).
The QUAD system contains mainly three function: i) automatically exclude low quality images that is ineligible for analysis in cases of halation, inadequate air de­livery, proximity to mucosa, chromoendoscopy, and virtual chromoendoscopy; ii) fully auto­mated twelve-class score output based on frame analysis: Each frame was divided into four quadrants; inflammation in each quadrant was graded 0–3 and summed to yield a QUAD score of 0–12; and iii) full-length withdrawal videos were processed to generate (I) an Entire QUAD (0–60) for considering whole-colon inflammation status and (II) a Distal QUAD (0–12) for the distal rectum–sigmoid segment (final 20 % of the video). An open-label cohort of adults with quiescent UC (partial Mayo score ≤ 2 for ≥6 months) was prospectively enrolled at a single center (August 2022–February 2023), and followed for 24 months after baseline colonoscopy; clinical relapse was defined as partial Mayo score > 2. The predictive value of QUAD scores for relapse was evaluated.

Results

Frame-level QUAD scores correlated strongly with expert-assigned MES values (Spearman r = 0.68, p < 0.01). Among 156 participants (median age, 51 years; 49 % male), 22 experienced relapse during follow-up. Relapse occurred in 19.4 % (19/98) of patients with a QUAD score > 3 versus 5.2 % (3/58) with a score ≤ 3 (log-rank p = 0.01).
In video analysis, an Entire QUAD > 6 did not significantly stratify relapse risk (16.8 % [17/101] vs 9.1 % [5/55]; log-rank p = 0.17). In contrast, a Distal QUAD > 3 was strongly associated with relapse (43.8 % [7/16] vs 10.7 % [15/140]; log-rank p < 0.01).

Conclusion

AI-generated QUAD provides a sensitive, fully quantitative measure of mucosal inflammation and stratifies relapse risk in clinically quiescent UC. In particular, the automatically derived Distal QUAD—focused on the distal colon and independent of operator image selection—offers a practical, objective tool for longitudinal monitoring and treatment tailoring in UC.