eoe sub articles

EoE Sub Articles

NOTE: As a convenient point of reference for readers, the following methodology describes the specific culture conditions and materials required for the measurement of Fe bioavailability from 20 experimental samples, plus the required quality controls, in a run of the bioassay. Increasing the number of samples beyond this capacity is not recommended due to the time required for various cell culture and in vitro digestion steps within the bioassay.
1. Choosing the amount...

caco-2 cell bioassay: an in vitro method for measuring iron bioavailability in complex food sources

Source: Glahn, R. P. <a href="https://app.jove.com/v/63859">The Caco-2 Cell Bioassay for Measurement of Food Iron Bioavailability.</a> J. Vis. Exp. (2022)
This video demonstrates an in vitro technique to assess iron bioavailability in complex food sources. The technique combines the simulation of human digestion along with iron uptake by differentiated Caco-2 cells. Intracellular ferritin formation acts as a marker for cellular iron uptake.

<img alt="Figure 1" src="/files/ftp_upload/21211/21211_Figure1.jpg" /> 
Figure 1: Insert ring setup for Caco-2 cell Fe uptake. (A) Image of Caco-2 cells and insert ring with attached dialysis membrane. (B) Diagram of the overall procedure for in vitro digestion coupled with Caco-2 cell Fe uptake within a single well of the multi-well plate.

Caco-2 Cell Bioassay: An In Vitro Method for Measuring Iron Bioavailability in Complex Food Sources

Source: Glahn, R. P. The Caco-2 Cell Bioassay for Measurement of Food Iron Bioavailability. J. Vis. Exp. (2022)
This video demonstrates an in vitro ...

Enterocytes are specialized small intestine cells that play a crucial role in nutrient uptake, including iron absorption.
To assess iron bioavailability - the proportion of ingested iron accessible for physiological functions - take an acidified solution containing the food sample. Now, add pepsin - a protein digestion enzyme, from the stomach. At acidic pH, pepsin initiates gastric digestion by breaking down complex dietary proteins into small peptides.
Add sodium bicarbonate to increase the pH and stop gastric digestion. Add a solution containing pancreatic enzymes and bile to simulate intestinal digestion. Transfer the mixture into the upper portion of a two-chamber cell culture system.
The lower chamber contains enterocytes differentiated from Caco-2 - a colon adenocarcinoma cell line. A dialysis membrane separates the upper chamber from the lower one. The membrane allows the diffusion of low molecular weight species.
The pancreatic enzymes-bile mixture in the upper chamber breaks down carbohydrates, proteins, and lipids into smaller subunits - releasing iron in the form of ferric ions.
Bioavailability enhancers in the food convert the released ferric ions to the ferrous state - increasing their solubility. These ions pass through the membrane to reach the lower chamber.
Metal ion transporters in the cell membrane of enterocytes aid in the uptake of ferrous ions. Once inside, iron binds to apoferritin - an iron storage protein resulting in a complex, ferritin. Harvest the cells to quantify ferritin to assess iron bioavailability.

Caco-2 Cell Bioassay: An In Vitro Method for Measuring Iron Bioavailability in Complex Food Sources

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