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

Area of Science:

• Gastroenterology
• Immunology
• Pathology

Background:

• Ulcerative colitis (UC) is a chronic inflammatory bowel disease affecting the large intestine.
• Accurate assessment of inflammatory markers is crucial for understanding disease severity and guiding treatment.
• Quantitative analysis of cytokines in different bowel segments can provide insights into disease localization and activity.

Purpose of the Study:

• To quantitatively analyze the expression of pro-inflammatory cytokines Interleukin-1 (IL-1), Interleukin-6 (IL-6), and Tumor Necrosis Factor-alpha (TNF-α) in surgically excised large bowel segments from ulcerative colitis patients.
• To correlate the spatial distribution and levels of these cytokines with specific clinical symptoms and disease severity.
• To evaluate the utility of digital image analysis for quantitative immunohistochemistry in inflammatory bowel disease research.

Main Methods:

• Spatial visualization and digital image analysis were employed for quantitative assessment of IL-1, IL-6, and TNF-α.
• Immunohistochemistry was performed on large bowel tissue samples from 17 patients undergoing restorative proctocolectomy for ulcerative colitis.
• Cytokine expression was quantified using area and intensity fractions and categorized with the Alfred Immunohistochemistry Score.

Main Results:

• A significantly higher expression of IL-1, IL-6, and TNF-α was observed in rectal segments compared to colonic segments (p<0.01).
• Elevated cytokine levels, particularly in the rectum, were associated with the patients' clinical condition and disease severity.
• Patients exhibiting symptoms like bloody and mucus stools showed a stronger correlation between higher cytokine expression and intensified clinical disease course.

Conclusions:

• Quantitative immunohistochemistry using digital image analysis is a viable method for correlating biomarker expression with clinical symptoms in ulcerative colitis.
• Evaluation of inflammatory cytokines (IL-1, IL-6, TNF-α) is recommended during the active stage of ulcerative colitis, especially when symptoms like bloody/mucus stools are present.
• Assessing cytokine levels during remission or clinically silent stages may not yield significant correlations or clinical utility.