Katharina Buczek
In a 2020 study conducted by Fleckenstein, he found that ETEC’s toxins do much more than just push patients to take up residency in the bathroom.
Instead, one of the toxins– known as heat-labile toxin– actually impacts gene expression in the gut, which ultimately leads to more bacteria sticking to the intestinal wall.
And in the more recent Washington University study, it was discovered that the toxin even suppresses an entire group of genes that are related to the intestinal lining– in other words, where nutrients are absorbed.
This intestinal border is typically made up of microscopic projections that are tightly packed and resemble bristles on a brush– known as microvilli.
After the ETEC toxin was applied to clusters of human intestinal cells, though, this intestinal border just disintegrated.
“Instead of being nice and tight and upright with thousands of microvilli per cell, they are short, floppy and sparse, kind of like if you had plucked out most of the bristles and what was left was kind of raggedy,” detailed Alaullah Sheik, a co-leader of the study.
So, that alone would severely impact anybody’s ability to absorb nutrients. In addition to that discovery, though, the researchers also found that genes linked to the absorption of specific minerals and vitamins– such as zinc and vitamin B1– were also downregulated.
“That could explain some of the micronutrient deficiencies we see in children repeatedly exposed to these bacteria,” Sheik said.
And since children who live in poorer nations often suffer repeated bouts of diarrhea, the risk of growth stunting and malnutrition only increases with every single infection.
In turn, the researchers now believe that if the ETEC toxin is the issue, then an immune response that works to neutralize that toxin may be able to prevent long-term effects.
The team tested this theory by vaccinating nursing mouth mothers with the toxin– since it is not safe to immunize suckling mice themselves as they are too young.
