Intestinal Epithelial Digestive, Transport, and Barrier Protein Expression Is Increased in Environmental Enteric...

Area of Science:

• Gastroenterology
• Pediatric Nutrition
• Epithelial Biology

Background:

• Environmental enteric dysfunction (EED) is a major cause of childhood malnutrition and impaired development in low-resource settings.
• EED is characterized by chronic diarrhea, malabsorption, and intestinal inflammation, leading to long-term physical and cognitive deficits.

Purpose of the Study:

• To investigate the expression of transport and tight junction proteins in duodenal biopsies from children with EED.
• To compare protein expression in EED patients with healthy controls and other intestinal conditions.

Main Methods:

• Quantitative multiplex immunofluorescence microscopy was used to analyze duodenal biopsies.
• Samples were obtained from Pakistani children with EED and age-matched North American controls, including those with celiac disease and non-celiac disease with villous atrophy.

Main Results:

• EED biopsies showed partial villous atrophy, intraepithelial lymphocytosis, and goblet cell expansion.
• Increased expression of nutrient/water absorption proteins and basolateral NKCC1 was observed.
• The tight junction protein claudin-4 (CLDN4) was significantly upregulated in EED enterocytes.

Conclusions:

• EED triggers adaptive epithelial responses, increasing proteins for nutrient absorption and barrier function.
• Despite these adaptive changes, the intestinal barrier function and absorption remain compromised in EED.
• These upregulated proteins are insufficient to fully restore intestinal health in affected children.