Hereditary Hemochromatosis

Iron Absorption and Transport by Intestinal Epithelium

January 2009

The duodenal crypt cell serves as a significant storage and regulatory cell for iron. The presence of ferric iron in blood plasma stimulates the formation of a complex involving beta-2 microglobulin, transferrin receptor-1 and the membrane bound HFE protein to facilitate the transport of iron by a process of endocytosis. Iron is also intercollated into endocytes via Transferrin Receptor 2. Endocytic iron is then transported by DMT1 into the cellular iron pool of the crypt cell. Iron is recirculated back into the blood capillary via the iron transporter, ferroportin. What ferrous iron is returned to the plasma pool is oxidized to ferric iron by membrane bound hephaestin. This iron cycling process is modulated by a circulating protein called hepciden created by the liver. Hepciden causes ferroportin to alter its position in the cell membrane, reducing transport of ferrous iron into the blood capillary.

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Jump to section:

• Introduction
• Hereditary Hemochromatosis
• Normal Iron Absorption and Distribution
• Iron Overload Absorption and Distribution
• Iron Uptake, Preservation and Elimination
• Duodenum
• Iron Absorption and Transport by Intestinal Epithelium
• Iron Absorption and Transport by Intestinal Epithelium
• Hemochromatosis-Related Iron Accumulation
• Iron Absorption, Conservation and Transport by Hepatocyte
• Iron Absorption, Conservation and Transport in Hemochromatosis
• Effect of Hemochromatosis on Duodenal Crypt Cell
• Iron Absorption, Conservation and Transport in Hemochromatosis
• Clinical Presentation
• Clinical Presentation
• Hemochromatosis - Clinical Syndrome
• Laboratory Diagnosis: Serum Testing
• HFE Gene
• Hereditary Hemochromatosis
• Inheritance
• Genetic Testing
• Diagnostic Testing Algorithm
• Hemochromatosis - Gross Liver
• Hemochromatosis - Liver Microscopic
• Laboratory Diagnosis
• Treatment
• Summary
• Questions?