Experimental models of inflammatory bowel disease

Area of Science:

• Gastroenterology
• Immunology
• Pharmacology

Background:

• The etiology of inflammatory bowel disease (IBD) remains largely unknown.
• Numerous experimental models, classified as spontaneous or induced, have been developed to study IBD.
• These models generally exhibit chronic gut inflammation, often secondary to mucosal abnormalities and aberrant immune responses to luminal contents.

Purpose of the Study:

• To identify experimental models that closely mimic IBD's clinical, pathological, and early mucosal characteristics.
• To evaluate nonsteroidal anti-inflammatory drug (NSAID) enteropathy as a relevant model for Crohn's disease (CD).

Main Methods:

• Review and classification of existing spontaneous and induced experimental models for IBD.
• Comparative analysis of NSAID enteropathy with known characteristics of Crohn's disease, focusing on early mucosal changes.
• Examination of the sequence of events in NSAID enteropathy, including increased intestinal permeability and subsequent inflammatory lesions.

Main Results:

• NSAID enteropathy presents increased intestinal permeability early after NSAID administration, preceding inflammatory lesions.
• These inflammatory lesions in NSAID enteropathy appear secondary to increased permeability and are influenced by intraluminal factors (e.g., antigens, bacterial fragments).
• A potential mechanism linking increased permeability to inflammation involves an abnormal immune response to intraluminal materials.

Conclusions:

• NSAID enteropathy serves as a valuable experimental model for Crohn's disease due to its shared characteristic of early increased intestinal permeability.
• The pathophysiology of NSAID enteropathy suggests that increased intestinal permeability may precede and contribute to inflammatory lesions.
• If confirmed in CD, similar mechanisms involving increased intestinal permeability and subsequent immune responses could play a significant role in its development.