Tools and advanced imaging technologies for assessing intestinal epithelial barrier integrity: a systematic review

Area of Science:

• Gastroenterology
• Immunology
• Biomedical Engineering

Background:

• The intestinal epithelium forms a critical barrier regulating nutrient absorption and antigen entry.
• Barrier dysfunction contributes to inflammation and various gastrointestinal and systemic diseases.
• Early detection of epithelial alterations is vital for therapeutic intervention.

Purpose of the Study:

• To systematically review current methods for assessing intestinal epithelial barrier alterations.
• To evaluate the strengths and limitations of in vivo and in vitro assessment techniques.

Main Methods:

• Overview of non-invasive and invasive in vivo approaches (e.g., urinary probes, biomarkers, confocal laser endomicroscopy).
• Review of ex vivo/in vitro methods (e.g., transepithelial electrical resistance, impedance spectroscopy, organic electrochemical transistors).

Main Results:

• Non-invasive methods lack standardization and specificity.
• Invasive endoscopic techniques offer real-time visualization but are costly research tools.
• In vitro methods like TEER are standard, with newer technologies showing promise.
• Biomarkers and microbial translocation indicators require further validation.

Conclusions:

• Significant gaps exist in defining barrier breakdown, diagnostic tools, and validation.
• Methodological heterogeneity and unvalidated thresholds hinder clinical application.
• Further research is needed to develop standardized, validated diagnostic approaches for intestinal barrier function.