Extent of disease affects the usefulness of fecal biomarkers in ulcerative colitis

Misinterpretation and misapplication of biomarkers in inflammatory bowel disease: how do we avoid this?

INTRODUCTION

The management of inflammatory bowel disease (IBD) has evolved substantially over the past decade, with the emergence of new advanced therapies presenting unprecedented challenges in clinical decision-making. While these therapies provide patients with more opportunities to get better, biomarkers to guide their use remain elusive.

AREAS COVERED

This article highlights the challenges associated with biomarker discovery, interpretation, and application in IBD - based on literature review, first-hand experience of biomarker discovery, and personal opinion. We highlight problems including the misinterpretation of predictive capabilities, lack of independent validation, and reverse causation in retrospective studies, and explain why associations with clinical parameters or seropositivity to microbial antigens often fail to meet the rigorous performance metrics required for clinical utility. The relative need for different biomarkers is also discussed - particularly in light of recent evidence from the PROFILE trial, which emphasizes the considerably greater risk posed by uncontrolled disease than by the potential side-effects of medications.

EXPERT OPINION

Despite multiple challenges, the potential of biomarkers for precision medicine in IBD remains promising, particularly in combination with other clinical and biochemical parameters. Further research into combinatorial biomarker approaches is needed, but must be combined with learning how to communicate results that are inherently uncertain.

Laboratory Tests in Inflammatory Bowel Disease: An Evidence-Based Approach to Daily Practice

Inflammatory bowel diseases (IBDs) comprise a group of chronic gastrointestinal disorders characterized by periods of relapse and remission. The mainstay of treatment is medical, involving medications such as steroids, immune modulators, monoclonal antibodies (categorized as biologics), and small molecules. These medications can provide profound therapeutic benefits, but they can also cause severe and irreversible toxicities. Clinicians may utilize laboratory tests in the diagnosis and management of IBD including assessment of disease activity, monitoring medication response or toxicity, surveillance of infectious complications, and detection of nutritional deficiencies. Routine use of laboratory tests may help clinicians avoid reactivation of life-threatening infections such as tuberculosis or hepatitis B virus upon initiation of immune suppressive therapy. They can also be used to detect vitamin deficiencies such as B12 deficiency, which has the potential to cause irreversible neurologic damage. While some laboratory tests constitute established practices, the utility of newer tests such therapeutic drug monitoring (TDM) in the era of biologics is an evolving topic. Although clinical assessment with imaging, endoscopic, and histopathological examination is standard practice, laboratory tests serve as valuable adjuncts. We aim to explore the broad range of laboratory tests available to clinicians and to summarize their application in the current management of IBD in daily clinical practice, with special attention to updates in therapeutic drug monitoring.

Efficacy of sequential fecal-marker examination for evaluating gastrointestinal inflammation in solid food protein-induced enterocolitis syndrome

BACKGROUND

Food protein-induced enterocolitis syndrome caused by solid foods (Solid-FPIES) is a non-immunoglobulin E-mediated allergic disease characterized by delayed gastrointestinal symptoms. An oral food challenge (OFC) test, although necessary, can be inconclusive in cases with mild symptoms. Moreover, limited diagnostic marker availability highlights the need for novel surrogate markers. We aimed to examine the efficacy of fecal hemoglobin (FHb), lactoferrin (FLf), and calprotectin (FCp) over time in evaluating gastrointestinal inflammation degree in Solid-FPIES.

METHODS

This observational study included 40 patients and 42 episodes at Juntendo University Hospital and affiliated hospitals between October 2020 and March 2024 categorized into FPIES (12 patients with 11 egg yolk, 1 fish, and 1 soybean episodes), control (14 patients with 15 episodes), and remission (14 patients). Fecal tests were performed for 7 days following antigen exposure. The ratios of each value were divided by the baseline value and analyzed over time course.

RESULTS

The FPIES group had significantly higher peak ratios of all fecal markers than the control group (p < 0.01). The median FHb, FLf, and FCp ratios were 3.25, 9.09, and 9.79 in the FPIES group and 1.08, 1.29, and 1.49 in the control group, respectively. In the remission group, several patients had fluctuating fecal markers despite negative OFC, and one patient was diagnosed with FPIES by OFC with increased load. Receiver operating characteristic curve analyses revealed high diagnostic performance for each fecal marker in FPIES.

CONCLUSIONS

Sequential fecal marker examination proved valuable in diagnosing Solid-FPIES and evaluating the degree of gastrointestinal inflammation.

Fecal and Serum Granulocyte Protein Levels in Inflammatory Bowel Disease and Irritable Bowel Syndrome and Their Relation to Disease Activity

INTRODUCTION

Neutrophilic calprotectin (CP) and myeloperoxidase (MPO), neutrophil gelatinase-associated lipocalin (NGAL), and eosinophil-derived neurotoxin (EDN) are suggested proxy markers for gut inflammation. However, there are insufficient supporting data for MPO, NGAL, and EDN.

METHODS

In a cross-sectional investigation including adult patients, we studied the ability of CP, MPO, NGAL, and EDN, measured in fecal and serum samples, to differentiate between inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS), and to predict disease activity.

RESULTS

Fifty-nine patients had ulcerative colitis (UC), 38 had Crohn's disease, and 100 patients had IBS. The protein concentrations were higher in patients with IBD in the fecal samples ( P < 0.001) and the serum samples ( P < 0.01), and they correlated weakly (r s ≤0.38) between the sample sources. Fecal EDN was higher in patients with Crohn's disease compared with UC (1.79 vs 0.50 mg/kg, P = 0.016). The neutrophilic proteins were superior to EDN in the fecal samples for differentiating between patients with IBD and IBS. Fecal MPO (cutoff: 0.86 mg/kg) had the highest sensitivity (74.7%) and specificity (84.6%). Combining fecal CP and MPO increased the sensitivity to 82.3% (specificity: 73.6%). NGAL (cutoff: 196.9 μg/L) showed the best discriminating performance in serum (sensitivity: 62.9%; specificity: 68.0%). Serum NGAL (cutoff: 272.4 μg/L) predicted active disease in UC (Partial Mayo Score ≥2) with a sensitivity and specificity of 57.1% and 83.3%, respectively.

DISCUSSION

Fecal MPO and serum NGAL are promising novel biomarkers, in addition to fecal CP, for differentiating between IBD and IBS. Serum NGAL may also predict disease activity in patients with UC.

Predictors of the efficacy of vedolizumab in patients with ulcerative colitis

Vedolizumab is a treatment option for ulcerative colitis but data on predictors of treatment response remain insufficient to establish personalized treatment strategies. We aimed to investigate the real-world effectiveness of vedolizumab in adult patients with ulcerative colitis and explore factors involved in predicting treatment response. This single-center, single-arm, prospective observational study included 26 patients with clinically active ulcerative colitis patients' characteristics at baseline, epidemiological information, existing treatment, clinical activity index score, endoscopic score, and blood test data were collected. Serum levels of tumor necrosis factors alpha, interferon gamma, interleukin-4, interleukin-6, interleukin-10, interleukin-17, soluble mucosal addressin cell adhesion molecule 1, and soluble vascular cell adhesion molecule 1 were measured. Patient characteristics in the remission and non-remission groups were compared based on these parameters. Clinical remission at 6 weeks of treatment occurred in 9 (35%) of the 26 patients. At 14 weeks, clinical remission was observed in 11 patients (42%). There were no significant differences pertaining to age, sex, duration of disease, extent of disease, steroid resistance, or prior treatment with biological agents among the two groups after 14 weeks of treatment. Hemoglobin ≥ 11.5 g/dL (odds ratio, 15.0; 95% confidence interval, 1.50-149; P=0.014) and soluble mucosal addressin cell adhesion molecule 1 ≥ 765 pg/mL (odds ratio, 17.3; 95% confidence interval, 2.36-127; P=0.004) were significant factors. In conclusion, hemoglobin and serum soluble mucosal addressin cell adhesion molecule 1 levels are factors correlated with the therapeutic efficacy of vedolizumab.

Biomarkers in inflammatory bowel disease: a practical guide

Inflammatory bowel disease (IBD), comprising ulcerative colitis (UC) and Crohn's disease (CD), is a costly condition in terms of morbidity and healthcare utilization, with an increasing prevalence now approaching 1% in the Western world. Endoscopic assessment of IBD remains the gold standard for diagnosis, evaluation of treatment response and determination of post-operative recurrence, but is expensive and invasive. Biomarkers can facilitate non-invasive disease assessment, with C-reactive protein and faecal calprotectin as the most widely available biomarkers in current clinical practice. This narrative review summarizes the evidence for their use in both UC and CD and offers practical guidance for healthcare providers taking into account the limitations of biomarker interpretation. We present evidence for the future use of novel biomarkers in IBD and discuss how biomarker discovery could deliver the goal of precision medicine in IBD.

Current and emerging biomarkers for ulcerative colitis

INTRODUCTION

Ulcerative colitis (UC) is a chronic illness requiring lifelong management that could be enhanced by personalizing care using biomarkers.

AREAS COVERED

The main biomarker discovery modalities are reviewed, highlighting recent results across the spectrum of applications, including diagnostics (serum anti-αvβ6 antibodies achieving an area under the curve [AUC] = 0.99; serum oncostatin M AUC = 0.94), disease activity assessment (fecal calprotectin and serum trefoil factor 3: AUC > 0.90), prognostication of the need for treatment escalation (whole blood transcriptomic panels and CLEC5A/CDH2 ratio: AUC > 0.90), prediction of treatment response, and early identification of patients with subclinical disease. The use of established biomarkers is discussed, along with new evidence regarding autoantibodies, proteins, proteomic panels, transcriptomic signatures, deoxyribonucleic acid methylation patterns, and UC-specific glycomic and metabolic disturbances.

EXPERT OPINION

Novel biomarkers will pave the way for optimized UC care. However, validation, simplification, and direct clinical translation of complex models may prove challenging. Currently, few candidates exist to assess key characteristics, such as UC susceptibility, histological disease activity, drug response, and long-term disease behavior. Further research will likely not only reveal new tools to tackle these issues but also contribute to understanding UC pathogenesis mechanisms.

A novel inflammatory marker for extensive ulcerative colitis; Endocan

BACKGROUND & AIMS

Ulcerative colitis (UC) is an inflammatory bowel disease characterized by mucosal inflammation. Endocan, a proteoglycan secreted by endothelial cells in response to inflammatory cytokines, has been reported to be overexpressed in inflammatory conditions. In this study, we aimed to evaluate the utility of endocan level in determining the extent and severity of disease in patients with ulcerative colitis and to determine whether it can be a candidate marker for noninvasive evaluation and monitoring since there is not enough data in the literature.

MATERIALS AND METHODS

Sixty-five people were included in the study, including thirty-five with ulcerative colitis and thirty in the control group. Patients with first diagnosed ulcerative colitis clinically, endoscopically, and histopathologically, without any treatment, and with normal liver and kidney tests were included in the study. Endoscopic scoring of all patients was performed according to the Mayo endoscopic scoring (MES) system. Blood samples for CRP (C-reactive protein) and endocan were taken from the patients simultaneously.

RESULTS

There was a significant statistical difference between all patients with ulcerative colitis and the control group in both endocan level and CRP level (p < 0.001). There was a statistically significant difference between endocan levels and CRP levels between the left-distal group and pancolitis (diffuse colitis) patients, but there was no statistical difference between age and MES.

CONCLUSION

Serum endocan level can be useful in determining the extent of ulcerative colitis and planning treatment.

AGA Clinical Practice Guideline on the Role of Biomarkers for the Management of Ulcerative Colitis

BACKGROUND & AIMS

Biomarkers are used frequently for noninvasive monitoring and treatment decision making in the management of patients with ulcerative colitis (UC). This American Gastroenterological Association (AGA) guideline is intended to support practitioners in decisions about the use of biomarkers for the management of UC.

METHODS

A multidisciplinary panel of content experts and guideline methodologists used the Grading of Recommendations Assessment, Development and Evaluation framework to prioritize clinical questions, identify patient-centered outcomes, and conduct an evidence synthesis on the clinical performance of serum C-reactive protein (CRP), fecal calprotectin, and fecal lactoferrin as biomarkers of disease activity in patients with established UC in symptomatic remission or with active symptoms. The guideline panel used the Evidence-to-Decision framework to develop recommendations for the use of biomarkers for monitoring and management of UC and provided implementation considerations for clinical practice.

RESULTS

The guideline panel made 7 conditional recommendations. In patients with UC in symptomatic remission, the panel suggests the use of a biomarker- and symptom-based monitoring strategy over a symptom-based monitoring strategy. For patients in symptomatic remission, the panel suggests using fecal calprotectin <150 μg/g, normal fecal lactoferrin, and/or normal CRP to rule out active inflammation and avoid routine endoscopic assessment of disease. In patients with UC with moderate to severe symptoms, the panel suggests using fecal calprotectin >150 μg/g, elevated fecal lactoferrin, or elevated CRP to inform treatment decisions and avoid routine endoscopic assessment of disease. However, in patients in symptomatic remission but elevated biomarkers, and in patients with moderate to severe symptoms with normal biomarkers, the panel suggests endoscopic assessment of disease to inform treatment decisions. In patients with UC with mild symptoms, the panel suggests endoscopic assessment of disease activity to inform treatment decisions. The panel identified the use of a biomarker-based monitoring strategy over an endoscopy-based monitoring strategy as a knowledge gap. The panel also proposed key implementation considerations for optimal use of biomarkers, and identified areas for future research.

CONCLUSIONS

In patients with UC, noninvasive biomarkers, including fecal calprotectin, fecal lactoferrin, and serum CRP can inform disease monitoring and management.

Predictive models for endoscopic disease activity in patients with ulcerative colitis: Practical machine learning-based modeling and interpretation

Background

Endoscopic disease activity monitoring is important for the long-term management of patients with ulcerative colitis (UC), there is currently no widely accepted non-invasive method that can effectively predict endoscopic disease activity. We aimed to develop and validate machine learning (ML) models for predicting it, which are desired to reduce the frequency of endoscopic examinations and related costs.

Methods

The patients with a diagnosis of UC in two hospitals from January 2016 to January 2021 were enrolled in this study. Thirty nine clinical and laboratory variables were collected. All patients were divided into four groups based on MES or UCEIS scores. Logistic regression (LR) and four ML algorithms were applied to construct the prediction models. The performance of models was evaluated in terms of accuracy, sensitivity, precision, F1 score, and area under the receiver-operating characteristic curve (AUC). Then Shapley additive explanations (SHAP) was applied to determine the importance of the selected variables and interpret the ML models.

Results

A total of 420 patients were entered into the study. Twenty four variables showed statistical differences among the groups. After synthetic minority oversampling technique (SMOTE) oversampling and RFE variables selection, the random forests (RF) model with 23 variables in MES and the extreme gradient boosting (XGBoost) model with 21 variables in USEIS, had the greatest discriminatory ability (AUC = 0.8192 in MES and 0.8006 in UCEIS in the test set). The results obtained from SHAP showed that albumin, rectal bleeding, and CRP/ALB contributed the most to the overall model. In addition, the above three variables had a more balanced contribution to each classification under the MES than the UCEIS according to the SHAP values.

Conclusion

This proof-of-concept study demonstrated that the ML model could serve as an effective non-invasive approach to predicting endoscopic disease activity for patients with UC. RF and XGBoost, which were first introduced into data-based endoscopic disease activity prediction, are suitable for the present prediction modeling.

Recent advances in clinical practice: advances in cross-sectional imaging in inflammatory bowel disease

Endoscopy remains the reference standard for the diagnosis and assessment of patients with inflammatory bowel disease (IBD), but it has several important limitations. Cross-sectional imaging techniques such as magnetic resonance enterography (MRE) and intestinal ultrasound (IUS) are better tolerated and safer. Moreover, they can examine the entire bowel, even in patients with stenoses and/or severe inflammation. A variety of cross-sectional imaging activity scores strongly correlate with endoscopic measures of mucosal inflammation in the colon and terminal ileum. Unlike endoscopy, cross-sectional techniques allow complete visualisation of the small-bowel and assess for extraintestinal disease, which occurs in nearly half of patients with IBD. Extramural findings may predict outcomes better than endoscopic mucosal assessment, so cross-sectional techniques might help identify more relevant therapeutic targets. Coupled with their high sensitivity, these advantages have made MRE and IUS the primary non-invasive options for diagnosing and monitoring Crohn's disease; they are appropriate first-line investigations, and have become viable alternatives to colonoscopy. This review discusses cross-sectional imaging in IBD in current clinical practice as well as research lines that will define the future role of these techniques.

Progression risk factors of ulcerative proctitis

Ulcerative colitis (UC) is an inflammatory bowel disease of unknown etiology. It is characterized by a chronic course with periods of aggravations and remissions. Among patients, 25-55% present with ulcerative proctitis (UP) at the time of diagnosis. UP is well-treated disease associated with a good prognosis. UP is characterized by a less aggressive course than the left-sided form of UC and pancolitis, with a good response to topical treatment. Moreover, UP is associated with a lower risk of severe aggravations and systemic and local complications and lower need for colectomy, hospitalization and glucocorticosteroids and immunosuppressive drugs, in comparison with more extensive forms of the disease. Thus, the key issue is to prognose the natural course of the disease in order to identify high-risk patients and apply biological or immunosuppressive treatment early to prevent the development of complications. In this review, we summarize the current knowledge about the natural course of UP and discuss risks and protective factors related to disease progression and current treatment concepts.