Mixed micelle properties and intestinal cholesterol uptake.
Level 5 - mechanism / opinion, no new human data
In vitro laboratory study of micellar properties and uptake mechanisms.
PubMed 7093350 · doi:10.1016/s0300-9084(82)80492-6
What was done
The authors measured the solubilizing capacities of three bile salts (taurocholate, taurochenodeoxycholate, and tauroursodeoxycholate) for monoolein and cholesterol, along with the physical size of the resulting mixed micelles. They then measured intestinal cholesterol uptake in vitro as a function of micellar size and cholesterol saturation level.
What was found
Micellar size depended on monoolein saturation. For a given bile salt-to-monoolein ratio, taurochenodeoxycholate formed the smallest micelles, followed by taurocholate, while tauroursodeoxycholate formed the largest micelles. For in vitro intestinal cholesterol uptake at a given bile salt-to-monoolein ratio: taurocholate produced the highest uptake rate at low cholesterol concentrations, whereas taurochenodeoxycholate induced the greatest uptake at high cholesterol concentrations. Tauroursodeoxycholate supported very little cholesterol uptake. Exact quantitative values were not reported in the abstract.
Why it matters
The study outlines the biophysical micellar mechanisms that explain why ursodeoxycholic acid conjugates are relatively ineffective at facilitating intestinal cholesterol absorption compared to other physiological bile salts.
Limits
This is purely an in vitro experimental study with no in vivo validation or human clinical data. The abstract lacks exact numerical values, variance measures, statistical test results, and specific details regarding the biological tissue or membrane model used for uptake measurements.
Cited by
- context TUDCA is mostly water-soluble rather than fat-soluble, preventing it from aiding fat digestion.