Digital image analysis of inflammation markers in colorectal mucosa by using a spatial visualization method

Abstract

The aim of this study was to apply the spatial visualization method of digital images to quantitative analysis of pro-inflammatory cytokines IL-1, IL-6 and TNF-α in various segments of large bowel excised because of colitis ulcerosa in relation with selected clinical symptoms. Our preliminary study included 17 patients having undergone restorative proctocolectomy. Immunohistochemistry was performed for IL-1, IL-6 and TNF-α. The area fraction and intensity fraction of the cytokines studied were determined by digital image analysis. The results were then categorized using Alfred Immunohistochemistry Score. The expression of IL-1, IL-6 and TNF-α was significantly higher in the rectum than in colonic segments (p<0.01), and was associated with the patients' clinical condition. The method of quantitative immunohistochemistry presented here allows for searching associations between the expression of biomarkers and clinical symptoms. Evaluation of inflammatory cytokines could be recommended in the active stage of the disease with present symptoms of bloody and mucus stools. A higher expression of IL-1, IL-6 and TNF in samples beyond large intestine correlates with an intensified clinical course of the disease. In patients without bleeding and mucus symptoms present in stools, no significant correlations were found. Therefore, the assessment of cytokines during remission or clinically silent stage might not be useful.

Keywords: Digital image analysis; IL-1; IL-6; TNF-α; Ulcerative colitis.