Gut integrity and duodenal enteropathogen burden in undernourished children with environmental enteric dysfunction

Abstract

Environmental enteric dysfunction (EED) is a subclinical condition of intestinal inflammation, barrier dysfunction and malabsorption associated with growth faltering in children living in poverty. This study explores association of altered duodenal permeability (lactulose, rhamnose and their ratio) with higher burden of enteropathogen in the duodenal aspirate, altered histopathological findings and higher morbidity (diarrhea) that is collectively associated with linear growth faltering in children living in EED endemic setting. In a longitudinal birth cohort, 51 controls (WHZ > 0, HAZ > −1.0) and 63 cases (WHZ< -2.0, refractory to nutritional intervention) were recruited. Anthropometry and morbidity were recorded on monthly bases up to 24 months of age. Dual sugar assay of urine collected after oral administration of lactulose and rhamnose was assessed in 96 children from both the groups. Duodenal histopathology (n = 63) and enteropathogen analysis of aspirate via Taqman array card (n = 60) was assessed in only cases. Giardia was the most frequent pathogen and was associated with raised L:R ratio (p = 0.068). Gastric microscopy was more sensitive than duodenal aspirate in H. pylori detection. Microscopically confirmed H. pylori negatively correlated with HAZ at 24 months (r = −0.313, p = 0.013). Regarding histopathological parameters, goblet cell reduction significantly correlated with decline in dual sugar excretion (p< 0.05). Between cases and controls, there were no significant differences in the median (25th, 75th percentile) of urinary concentrations (μg/ml) of lactulose [27.0 (11.50, 59.50) for cases vs. 38.0 (12.0, 61.0) for controls], rhamnose [66.0 (28.0, 178.0) vs. 86.5 (29.5, 190.5)] and L:R ratio [0.47 (0.24, 0.90) vs. 0.51 (0.31, 0.71)] respectively. In multivariable regression model, 31% of variability in HAZ at 24 months of age among cases and controls was explained by final model including dual sugars. In conclusion, enteropathogen burden is associated with altered histopathological features and intestinal permeability. In cases and controls living in settings of endemic enteropathy, intestinal permeability test may predict linear growth. However, for adoption as a screening tool for EED, further validation is required due to its complex intestinal pathophysiology.

Quantitative Morphometry and Machine Learning Model to Explore Duodenal and Rectal Mucosal Tissue of Children with Environmental Enteric Dysfunction

“…The total severity scores of cases from Pakistan with EED using the EEDBI consortium scoring scheme have already been published. 18 Upon assessment of celiac disease slides using the same scoring system, morphologic changes in duodenal histology were significantly more pronounced than EED cases, with average scores of 5 (4, 8) and 14 (11, 15), respectively ( Figure 4A ). Interestingly, in the cohort of undiagnosed cases, we observed similar severity scores as in the cohort with EED, suggesting the presence of some abnormalities not highlighted on initial histopathologic evaluation ( Supplemental Figure 2J ).…”

“… 17 The enrollment procedures and patient selection for endoscopic evaluation of EED have been published elsewhere. 18 A subset of patients diagnosed with EED also underwent flexible sigmoidoscopy with rectal biopsy if they had persistent diarrhea and/or blood in the stool.…”

Impact of enteropathogens on faltering growth in a resource-limited setting

“…Hence, further studies are required on the role of gut microbiota and enteropathogen co-colonization in undernourished children to gain insight into the pathophysiology of EED. In the context of stunting and malnutrition, our group has already reported increased intestinal permeability in children with Giardia detected in their duodenal aspirates, even in the absence of chronic inflammation of the gut tissue ( 15 , 18 ). Giardia sis has shown a minimal association with markers of intestinal inflammation, further suggesting a non-inflammatory mechanism ( 19 ).…”

Giardia and growth impairment in children in high-prevalence settings: consequence or co-incidence?

“…However, fecal myeloperoxidase (MPO), a marker of neutrophil inflammation, was lower in children with Giardia [37], and Giardia was not associated with increased fecal neopterin as a marker of T-cell activation or the acute phase reactant α-1-acid glycoprotein [7,38]. More directly, intestinal biopsies of stunted children in Pakistan with Giardia infection reveal diminished expression of lymphocyte genes [39 ▪▪ ] despite simultaneous associations with increased gut permeability [40], an apparent contradiction to the EED paradigm of parasite-mediated gut-inflammation pathway of growth impairment. Thus, while impaired gut function represents a putative pathway for poor growth during giardiasis, the mechanisms appear to be independent of both diarrhea and inflammation.…”