A Serum Biomarker Panel Can Accurately Identify Mucosal Ulcers in Patients With Crohn's Disease.

BACKGROUND: The Endoscopic Healing Index (EHI) is a serum biomarker panel that can predict endoscopic inflammation in Crohn's disease (CD). METHODS: Paired serum samples with endoscopies from adult patients participating in a prospective biobank (June 2014 to December 2018) were analyzed post hoc. Diagnostic performance for EHI was assessed against the individual parameters of the Simple Endoscopic Score for CD using previously identified cutoffs. Confounders for EHI performance were identified using logistic regression. RESULTS: A total of 205 CD patients were included (50% male, median age 37 years). An EHI of 20 points was sensitive for ruling out any ulcers (85%; 95% confidence interval [CI], 77%-91%) and large (5-20 mm) or very large (>20 mm) ulcers (93%; 95% CI, 84%-97%). An EHI of 50 points was specific for ruling in any ulcers (86%; 95% CI, 76%-92%) and large or very large ulcers (87%; 95% CI, 79%-92%). After accounting for total extent of inflamed mucosa, strictures, and disease location, each 20-point increase in EHI was associated with a 1.7-fold increased probability for the presence of large or very large ulcers (adjusted odds ratio, 1.7; 95% CI, 1.1-2.6). CONCLUSIONS: The EHI was independently associated with ulcer size and accurately identified large or very large ulcers. A cutoff of 50 points can reliably rule in mucosal ulcers and allow for treatment adjustment. A cutoff of 20 points can reliably rule out mucosal ulcers and signal completion of treatment adjustment algorithms.

Gastrointestinal Surgery for Inflammatory Bowel Disease Persistently Lowers Microbiome and Metabolome Diversity.

BACKGROUND: Many studies have investigated the role of the microbiome in inflammatory bowel disease (IBD), but few have focused on surgery specifically or its consequences on the metabolome that may differ by surgery type and require longitudinal sampling. Our objective was to characterize and contrast microbiome and metabolome changes after different surgeries for IBD, including ileocolonic resection and colectomy. METHODS: The UC San Diego IBD Biobank was used to prospectively collect 332 stool samples from 129 subjects (50 ulcerative colitis; 79 Crohn's disease). Of these, 21 with Crohn's disease had ileocolonic resections, and 17 had colectomies. We used shotgun metagenomics and untargeted liquid chromatography followed by tandem mass spectrometry metabolomics to characterize the microbiomes and metabolomes of these patients up to 24 months after the initial sampling. RESULTS: The species diversity and metabolite diversity both differed significantly among groups (species diversity: Mann-Whitney U test P value = 7.8e-17; metabolomics, P-value = 0.0043). Escherichia coli in particular expanded dramatically in relative abundance in subjects undergoing surgery. The species profile was better able to classify subjects according to surgery status than the metabolite profile (average precision 0.80 vs 0.68). CONCLUSIONS: Intestinal surgeries seem to reduce the diversity of the gut microbiome and metabolome in IBD patients, and these changes may persist. Surgery also further destabilizes the microbiome (but not the metabolome) over time, even relative to the previously established instability in the microbiome of IBD patients. These long-term effects and their consequences for health outcomes need to be studied in prospective longitudinal trials linked to microbiome-involved phenotypes.

Biomarkers are associated with clinical and endoscopic outcomes with vedolizumab treatment in Crohn's disease.

BACKGROUND: Vedolizumab, an α4ß7 integrin antagonist, is an effective therapy for Crohn's disease (CD). Biomarkers are needed to guide therapy and predict outcomes. This study evaluated biomarker concentrations and outcomes in patients with CD undergoing vedolizumab treatment. METHODS: Sera at weeks 0, 2, 6, 14, and ⩾26 were collected from vedolizumab-treated, refractory CD patients. Concentrations of soluble (s)-Vascular Cell Adhesion Molecule (VCAM)-1, s-Intercellular Cell Adhesion Molecule (ICAM)-1, s-Mucosal Addressin Cell Adhesion Molecule (MAdCAM)-1, and s-α4ß7 integrin were evaluated for associations with achieving endoscopic remission. RESULTS: A total of 22 patients with CD were included. In all patients, s-MAdCAM-1 decreased significantly and s-α4ß7 increased compared with baseline. s-VCAM-1 and s-ICAM-1 changed differentially in patients who achieved remission. At week 6, median s-VCAM-1 (859.6 ng/ml versus 460.3 ng/ml, p = 0.03) and s-ICAM-1 (545.7 ng/ml versus 286.2 ng/ml, p = 0.03) concentrations were higher in patients who achieved endoscopic remission compared with those who did not, and similar differences were observed for s-ICAM-1 concentrations in patients who achieved clinical remission, compared with those who did not (669.1 ng/ml versus 291.0 ng/ml, p = 0.04). Week 14 s-α4ß7 concentrations were lower in patients who achieved endoscopic remission, compared with those who did not (7.5 ng/ml versus 17.6 ng/ml, p = 0.020). CONCLUSION: In all vedolizumab-treated CD patients, s-MAdCAM-1 decreased significantly and s-α4ß7 increased. However, higher concentrations of s-ICAM-1 and s-VCAM-1 at week 6 and lower concentrations of s-α4ß7 at week 14 differentiated patients who achieved endoscopic remission. These findings may help identify early predictors of response to vedolizumab treatment in patients with CD. Further validation in less refractory CD patients is needed.

Heterogeneity and clonal relationships of adaptive immune cells in ulcerative colitis revealed by single-cell analyses.

Inflammatory bowel disease (IBD) encompasses a spectrum of gastrointestinal disorders driven by dysregulated immune responses against gut microbiota. We integrated single-cell RNA and antigen receptor sequencing to elucidate key components, cellular states, and clonal relationships of the peripheral and gastrointestinal mucosal immune systems in health and ulcerative colitis (UC). UC was associated with an increase in IgG1+ plasma cells in colonic tissue, increased colonic regulatory T cells characterized by elevated expression of the transcription factor ZEB2, and an enrichment of a γδ T cell subset in the peripheral blood. Moreover, we observed heterogeneity in CD8+ tissue-resident memory T (TRM) cells in colonic tissue, with four transcriptionally distinct states of differentiation observed across health and disease. In the setting of UC, there was a marked shift of clonally related CD8+ TRM cells toward an inflammatory state, mediated, in part, by increased expression of the T-box transcription factor Eomesodermin. Together, these results provide a detailed atlas of transcriptional changes occurring in adaptive immune cells in the context of UC and suggest a role for CD8+ TRM cells in IBD.