Evaluation of biomarkers for ulcerative colitis comparing two sampling methods: fecal markers reflect colorectal inflammation both macroscopically and on a cellular level

Abstract

Objective: Simple, objective and inexpensive tools for the assessment of mucosal inflammation in ulcerative colitis (UC) are highly desirable. The aim of this study was to evaluate a broad spectrum of activity markers comparing two sampling methods: fecal samples and the mucosal patch technique.

Methods: Twenty patients with active UC and 14 healthy controls were characterized by means of clinical indices and endoscopy together with histology and immunohistochemistry on colorectal sections. Neutrophil myeloperoxidase (MPO), calprotectin, eosinophil cationic protein (ECP), eosinophil protein X (EPX/EDN) and IL-1β were analyzed in fecal samples and rectal fluid collected by the patch technique. Nitric oxide (NO) was analyzed in rectal gas samples. Expression of activity markers on colorectal neutrophils and eosinophils were analyzed by flow cytometry.

Results: All fecal and patch markers were increased in UC patients compared with healthy controls. Fecal markers and the level of neutrophil activation correlated to disease activity, whereas patch markers did not. The best markers in terms of discriminative power were fecal MPO and IL-1β. Fecal marker levels were related to sigmoidal histology scores and to neutrophil number and activation. Patch markers were related to rectal inflammation only.

Conclusions: The levels of inflammation markers in feces and patch fluid distinctly reflected active inflammation in UC. The degree of disease activity was however best assessed by fecal markers, particularly MPO and IL-1β. Fecal markers reflect colorectal inflammation both macroscopically and on a cellular level, and may be useful for the evaluation of subclinical inflammation. The applicability of patch markers is restricted to rectal inflammation.

Keywords:

• Eosinophil
• fecal markers
• inflammatory bowel disease
• mucosal patch technique
• neutrophil

Acknowledgements

We are grateful to Britt-Inger Nyberg and Ingrid Stolt for excellent technical support during the study.

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Funding information

This study was carried out within the MIDAS consortium and supported by grants from Swedish Governmental Agency for Innovation Systems (VINOVA), Diary No. 2007-00084. The funding sources had no involvement in study design; in the collection, analysis and interpretation of data; in the writing of the report; or in the decision to submit the article for publication.

Ethical statement

The study was approved by the Ethical Committee of the Medical Faculty, Uppsala University, and all patients gave written informed consent to participation in the study.