Iron is an essential cellular metal that is important for many physiological functions, however the mechanisms regulating iron absorption have been uncertain until now. In a study recently published in Blood, a research team from MedUni Vienna reports the discovery that duodenal macrophages play an important role in iron absorption in the body.
The research specifically revealed that the activation of macrophages directly in the duodenum leads to a halt in iron availability in the body. "We were able to determine that the macrophages in the duodenum eat away the iron transport molecule transferrin, so to speak. This means that the iron remains in the intestinal cells and can no longer enter the bloodstream," explains first author Nyamdelger Sukhbaatar.
In addition, the study found that macrophages are also activated during fasting, food intake, or during an intestinal infection, thereby changing the amount of transferrin in the intestine. "Our findings thus represent a real paradigm shift, as it was previously assumed that transferrin is always present in equal amounts everywhere in the body and does not actually play any role in iron regulation," add study leader Thomas Weichhart.
The team is currently investigating whether the macrophages in the intestine and their regulation of transferrin could also be disturbed in inflammatory bowel diseases, intestinal infections or gastritis. Potential therapeutic approaches already exist: In animal models, clinically approved drugs (mTOR inhibitors or serine protease blockers) were able to increase the amounts of transferrin and restore iron availability for the organism. Whether or not these treatment options can also be used in humans is to be researched in further studies.