Zonulin
Overview
Zonulin is a protein that modulates tight junctions between epithelial cells in the intestinal mucosa, regulating gut barrier permeability. It is released in response to luminal bacteria, gluten, or other triggers, temporarily opening intercellular junctions to allow antigen sampling. Elevated serum or fecal zonulin levels indicate increased intestinal permeability ("leaky gut"), associated with celiac disease, type 1 diabetes, and inflammatory bowel disease, while low levels suggest intact barrier function. Clinically, zonulin measurement assesses gut barrier integrity in autoimmune and inflammatory conditions, though evidence for routine diagnostic utility remains limited and controversial.wikipedia+1
Clinical Use Cases
- Assessment of intestinal permeability in celiac disease and non-celiac gluten sensitivity.
- Evaluation of gut barrier dysfunction in type 1 diabetes and autoimmune disorders.
- Monitoring therapeutic interventions aimed at restoring gut barrier function.
- Research biomarker for obesity, metabolic syndrome, and neurodegenerative diseases.
- Investigation of inflammatory bowel disease activity.
Specimen Types
- Serum.
- Fecal samples.
- Plasma (less common).
Measurement Methods
- Enzyme-linked immunosorbent assay (ELISA).
- Immunochromatographic lateral flow assays.
Test Preparation and Influencing Factors
- No fasting required.
- Gluten exposure or bacterial overgrowth increases zonulin release.
- Nonsteroidal anti-inflammatory drugs (NSAIDs) elevate levels.
- Probiotics and glutamine may normalize elevated levels.
- Sample stability varies; fecal samples require prompt freezing.
- Assay standardization inconsistent across manufacturers.
Synonyms
- Human zonulin.
- Pre-haptoglobin 2.