BACKGROUND
Environmental enteric dysfunction (EED) is an enigmatic disorder of the small intestine
postulated to play a role in childhood undernutrition, a pressing global health problem.
Defining the incidence of EED, its pathophysiology, and its contribution to impaired
linear and ponderal growth has been hampered by the difficulty in directly sampling the
small intestinal mucosa and microbial community (microbiota).
METHODS
Slum-dwelling Bangladeshi children aged 18±2 months, with linear
growth-faltering (stunting) who failed a nutritional intervention underwent endoscopy to
obtain duodenal biopsies and aspirates. Levels of 4077 plasma proteins and 2619 duodenal
proteins were quantified in 80 children with histopathologic evidence of EED, and the
abundances of bacterial strains in their duodenal microbiota were determined using
culture-independent methods. Young germ-free mice, fed a Bangladeshi diet, were
colonized with bacterial strains cultured from the duodenal aspirates.
RESULTS
The absolute abundances of a shared group of 14 bacterial strains recovered from the
duodenums of children with EED and not typically classified as enteropathogens were
negatively correlated with linear growth (length-for-age
Z-score;β=-0.38±0.12(SEM);ρ=-0.49;p=0.003), and positively
correlated with duodenal proteins involved in immunoinflammatory responses.
Representation of these 14 duodenal taxa was significantly different in fecal microbiota
from EED versus healthy children (p<0.001;PERMANOVA). Gnotobiotic mice colonized
with cultured EED-donor duodenal strains develop a small intestinal enteropathy.
CONCLUSIONS
These results provide evidence of a causal relationship between components of the small
intestinal microbiota, enteropathy and stunting and offer a rationale for developing
therapeutics that target what must no longer remain terra incognita-the small intestinal
microbiota. ClinicalTrials.gov identifier: NCT02812615