Measuring the ratio of lactulose to mannitol in urine does not reliably detect changes in intestinal permeability in people with inflammatory bowel disease compared to healthy individuals or between...
Mechanism
Synthesis from 1 study
When the gut lining gets damaged in inflammatory bowel disease, both sugars leak through more easily, so more of each ends up in the urine. But since they leak at the same increased rate, comparing them to each other doesn’t show how bad the damage is — only how much of each one shows up in the...
Most probable mechanism
In people with inflammatory bowel disease, the tight connections between gut lining cells become looser, letting more of both sugars pass through into the bloodstream. Because both sugars are absorbed at higher rates, they show up in greater amounts in urine, but since they both leak more equally, their ratio stays about the same.
Inflammatory mediators disrupt tight junction proteins between intestinal epithelial cells, increasing paracellular permeability
Both lactulose and 13C-mannitol diffuse more readily through the widened intercellular spaces due to their similar molecular sizes and passive transport mechanisms
The increased flux of both sugars into the bloodstream leads to proportionally elevated urinary excretion of each compound
Because the relative permeability of the intestinal barrier to both sugars remains unchanged, their urinary ratio does not reflect the degree of barrier dysfunction
Evidence from Studies
Supporting (1)
Community contributions welcome
Intestinal Permeability In Vivo in Patients With Inflammatory Bowel Disease: Comparison of Active Disease and Remission.
Contradicting (0)
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