The mechanism of intestinal haem iron absorption and characterization of a novel haem-binding protein

Funded Activity Summary

Iron is essential for normal health as many important proteins in the body require iron to function properly (e.g. haemoglobin). However, too much iron can be toxic, so the body must keep its iron content within defined limits. The amount of iron in the body is determined at the point of absorption from the diet in the small intestine. If too little iron is absorbed, then anaemia can result. If too much iron is absorbed, as is the case in the common disease haemochromatosis (with approximately 1 in 200 Australians at risk) then the body becomes iron loaded and various organs, particularly the liver, can become damaged. An understanding of how iron is absorbed will place us in a much better position to treat diseases such as this. Iron is present in the diet in two forms - inorganic iron and haem iron. Inorganic iron is the main form of iron in foods of plant origin while most haem iron comes from meat. In a typical diet 80-90% of the iron is inorganic iron and only 10-20% is haem. Despite this, 30-50% of the iron taken into the body comes from haem, so haem iron absorption is particularly efficient. While we have learned a great deal about the mechanims by which inorganic iron is absorbed in recent years, we know very little about the absorption of haem iron, so that is the focus of this project. We will study the pathway by which haem enters the body, how this process is regulated, and the characteristics of haem binding to the cells lining the small intestine. These cells are responsible for the uptake of all nutrients from the diet. In particular, we will examine the biology of a recently identified protein known as HCP1. Preliminary evidence suggests that HCP1 could be the main protein enabling haem to be taken up by intestinal cells. These studies will enhance our knowledge of an important nutritional pathway and improve our capacity to treat diseases such as haemochromatosis where iron absorption is defective.

Funded Activity Details

Start Date: 01-01-2006

End Date: 01-01-2008

Funding Scheme: NHMRC Project Grants

Funding Amount: $537,773.00

Funder: National Health and Medical Research Council

Research Topics

ANZSRC Field of Research (FoR)

Gastroenterology and Hepatology

ANZSRC Socio-Economic Objective (SEO)

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Other Keywords

haem | haemochromatosis | intestinal absorption | iron | iron deficiency | iron overload | nutrient transport | nutrition | physiology

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