Mechanisms Of Intestinal Iron Absorption And Consequences Of Iron Supplementation During The Perinatal Period
Funder
National Health and Medical Research Council
Funding Amount
$526,878.00
Summary
Iron intake is particularly high during pregnancy and in the newborn to meet the requirements of the growing fetus and neonate. While it is widely recommended that women take iron supplements at this time, too much iron may adversely affect pregnancy outcome. The aim of this study is to understand the factors controlling iron intake in the perinatal and the consequences of excess iron. This will provide the physiological information required to make rational decisions about iron supplementation.
Non-HFE Haemochromatosis In Australia: Natural History And Molecular Characterisation
Funder
National Health and Medical Research Council
Funding Amount
$179,948.00
Summary
Hereditary haemochromatosis (HH) is a disorder characterised by excessive iron absorption and build up of iron in body organs such as the liver. The excess iron can be toxic and cause disease. Most HH is caused by mutations in the HFE gene. Other forms are caused by mutations in other genes. This project will characterise a new form of HH that is unrelated to any of the previously known genes. The project aims to find the gene for this new condition by genetic analysis in a large family.
The Mechanism Of Intestinal Haem Iron Absorption And Characterization Of A Novel Haem-binding Protein
Funder
National Health and Medical Research Council
Funding Amount
$537,773.00
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 ....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.Read moreRead less
Red Cell Disorders And The Regulation Of Iron Homeostasis
Funder
National Health and Medical Research Council
Funding Amount
$605,096.00
Summary
Iron is an essential nutrient, but it is also toxic when present in excess, so the amount of iron moving into and around the body must be tightly controlled. In this project we will investigate how this body iron movement is regulated, and in particular the role played by macrophages, the cells that clean up old red blood cells. An understanding of this process will be of great benefit in the analysis and treatment of important blood diseases and disorders of iron metabolism.
Characterisation Of The Mechanisms Of Gastrointestinal And Hepatic Iron Transport In Hereditary Haemochromatosis
Funder
National Health and Medical Research Council
Funding Amount
$474,750.00
Summary
Hereditary haemochromatosis is a very common genetic disease that affects approximately 1:200 Australians. It alters the way the body uses iron. Iron is essential for health but too much iron is toxic to the body and causes harmful damage to organs. In hereditary haemochromatosis the body absorbs too much iron from the diet and most of the extra iron goes to the liver where it may cause liver cirrhosis and liver cancer. Some of the excess iron also goes to the heart, pancreas and joints where it ....Hereditary haemochromatosis is a very common genetic disease that affects approximately 1:200 Australians. It alters the way the body uses iron. Iron is essential for health but too much iron is toxic to the body and causes harmful damage to organs. In hereditary haemochromatosis the body absorbs too much iron from the diet and most of the extra iron goes to the liver where it may cause liver cirrhosis and liver cancer. Some of the excess iron also goes to the heart, pancreas and joints where it can lead to heart failure, diabetes and arthritis, respectively. There are several types of haemochromatosis that are caused by mutations in different genes that are important in the regulation of iron metabolism. In this study we will investigate two types of haemochromatosis caused by mutations in genes called HFE and transferrin receptor 2. How defects in these genes cause iron overload is not known. We will use laboratory models that have mutations in HFE and transferrin receptor 2 genes to identify for the first time how these proteins control the amount of iron the body absorbs from the diet and how much iron to delivered to the tissues such as the liver. From this study, we will gain a better understanding of the role of HFE and transferrin receptor 2 in both normal iron metabolism and haemochromatosis. This new knowledge will provide opportunities for the development of new more effective therapies for the prevention and treatment of iron overload.Read moreRead less
The Role Of Transferrin Receptor, Divalent Metal Transporter, Ferroportin And Hemochromatosis Protein In Iron Absorption
Funder
National Health and Medical Research Council
Funding Amount
$195,990.00
Summary
Within Australia 1 in 300 people of Caucasian origin have a genetic defect which makes them absorb more iron from the diet than they need. Excess iron is a major problem because it damages cells and this is most obvious in the pancreas where the cells make insulin are destroyed and diabetes mellitus develop. In the liver cirrhosis and cancer often occur. Iron also accumulates in other tissues such as the heart and joints resulting in damage to these organs. The genetic defect has recently been i ....Within Australia 1 in 300 people of Caucasian origin have a genetic defect which makes them absorb more iron from the diet than they need. Excess iron is a major problem because it damages cells and this is most obvious in the pancreas where the cells make insulin are destroyed and diabetes mellitus develop. In the liver cirrhosis and cancer often occur. Iron also accumulates in other tissues such as the heart and joints resulting in damage to these organs. The genetic defect has recently been identified but how the defective protein causes the cells of the intestine to absorb more iron into the body than is needed remains unknown. This has led to the idea that the normal protein is responsible for controlling the amount of iron absorbed. Recent studies have shown a link between this protein and another called transferrin receptor. These two molecules are thought to co-operate in determining how much iron will be absorbed. Once this is determined other molecules called iron transporters are produced and these are responsible for moving the iron from the intestine into the blood. When not much iron is required only a small number of transporters are made and when more iron is required then many more are produced. How these transporters program the level of iron absorption is unknown but the process probably involves the transferrin receptor and the hemochromatosis protein. This project will investigate the function of the molecules that determine the programe for how much iron is to be absorbed, and secondly how this is linked to the production and movement of the transproters that co-ordinate this function.Read moreRead less
The Role Of The Liver In The Pathogenesis Of Hereditary Haemochromatosis
Funder
National Health and Medical Research Council
Funding Amount
$592,023.00
Summary
Hereditary Haemochromatosis (HH) type 1 is a very common inherited disorder of iron metabolism that affects 1:200 Australians. HH is usually caused by mutations in the HFE gene and leads to excessive absorption of dietary iron and progressive iron loading of organs, particularly the liver. Undetected, progressive iron accumulation may have serious clinical consequences including cirrhosis, arthritis, diabetes mellitus and heart disease. The role of HFE in normal iron metabolism and how mutations ....Hereditary Haemochromatosis (HH) type 1 is a very common inherited disorder of iron metabolism that affects 1:200 Australians. HH is usually caused by mutations in the HFE gene and leads to excessive absorption of dietary iron and progressive iron loading of organs, particularly the liver. Undetected, progressive iron accumulation may have serious clinical consequences including cirrhosis, arthritis, diabetes mellitus and heart disease. The role of HFE in normal iron metabolism and how mutations in HFE lead to the development of Fe overload are unknown. Other types of HH have been identified that have similar clinical characteristics to HH type 1 which are due to mutations in hepcidin or haemojuvelin (type 2) and transferrin receptor 2 genes (type 3). It is thought that HFE acts together with these molecules in the same or closely related pathways to regulate iron metabolism. It is hypothesised that HFE and transferrin receptor 2 act as sensors of body iron levels which signal to the iron stores regulator, hepcidin to control the absorption of dietary iron and the deposition of iron in the liver. In this study, we will use mice with mutations in HFE and transferrin receptor 2 which have many of the characteristics of human HH type 1 and type 3 to identify 1) how HFE and transferrin receptor 2 sense body iron levels, 2) how they signal to hepcidin to regulate iron metabolism and 3) how mutations in HFE and transferrin receptor 2 lead to dysfunctional sensing of iron levels and impaired signalling to hepcidin causing increased iron absorption and liver iron overload in HH. This study will provide new knowledge about the role of HFE and other closely related molecules in the regulation of normal iron metabolism and the development of iron overload in HH and identify the potential of molecules such as hepcidin for therapeutical use for the prevention and treatment of iron overload.Read moreRead less