Advances in blood-based biomarkers of gut barrier integrity.

An intact gut barrier is crucial to human health. Functional assessment of gut barrier function and permeability in humans is laborious and demanding. Blood-based biomarkers that reflect gut barrier integrity have gained increasing attention for their potential role in monitoring gut barrier impairments across various conditions. Several candidate biomarkers-including intestinal fatty acid-binding protein, citrulline, zonulin, lipopolysaccharide-binding protein, and soluble CD14-reflect epithelial damage, microbial translocation, or tight junction dysfunction. This review highlights novel technologies for quantifying blood-based biomarkers to assess gut barrier function across diseases. Furthermore, it emphasizes the value of integrating complementary blood-based biomarkers across different populations to improve disease monitoring and the development of targeted therapies.