Non-invasive measurement of intestinal barrier function in environmental enteropathy using transcutaneous fluorescence sensing

Background Undernutrition represents a critical global health concern and is associated with a multifaceted breakdown in gut function—termed environmental enteropathy (EE)—which leads to increased intestinal permeability, inflammation and nutrient malabsorption. Current clinical approaches to assess intestinal permeability are costly, invasive, unreliable and/or difficult to perform in certain populations. Objectives We used transcutaneous fluorescence spectroscopy (TFS)—a novel method for non-invasive assessment of gut function—to investigate intestinal barrier function in EE. Design Volunteers were recruited in a Zambian community where EE is prevalent, and in the UK to undergo TFS measurements in a cross-sectional study. Data were compared between groups and were correlated with the lactulose:rhamnose (LR) test. Results TFS demonstrated significant differences in intestinal barrier function between UK and Zambian volunteers. Both peak fluorescence intensity (p=0.003) and area under fluorescence curves (p=0.02) were higher in Zambian than UK participants, suggesting increased permeation of TFS contrast agent. No differences were observed in time taken to reach peak, indicating no differences in factors affecting uptake rate (eg, gastric emptying). Finally, fluorescence kinetics and regression analysis revealed strong correlations between TFS data and urinary recoveries of lactulose and rhamnose (Spearman’s r≥0.78; p<0.002). Conclusions TFS reveals population differences in permeability. It also allows simultaneous assessment of multiple elements of gut function (intestinal barrier integrity and gastric emptying) using a rapid, sample-free methodology. Combined with correlation to the LR test, this implies potential to advance studies of gut health and to improve clinical monitoring.