iron out. iron built in mice with defective HFE genes (top), but not when a hepcidin gene is added (bottom).
a recently discovered peptide can prevent iron accumulation associated with a common genetic disorder, a new study. The disorder called hereditary hemochromatosis, affects one in 0 to 300 people, making it the largest of all known genetic diseases. The study points the way to new treatments for the disease.
Although iron deficiency is the worst nutritional problem in the world, it is possible to have too much of a good thing. Patients with hereditary hemochromatosis - most of which have two defective copies of a gene called HFE - absorb excess iron from their diet, overloading their bodies with metal, which can lead to lesions of large scale organ. Although the precise role of HFE in the iron flow control remained mysterious, scientists have suspected that the answer may come from a kind of "iron hormone," predicts a molecule to relay signals from the liver - which detects iron levels in the blood. - intestinal in particular, a hormone that can inhibit iron absorption could help explain what goes wrong in hereditary hemochromatosis, because the loss of such hormone probably lead to excessive iron absorption.
Now, a team led by Sophie Vaulont, a molecular biologist at the Cochin Institute in Paris, provided strong evidence that the long sought iron hormone hepcidin is. This small peptide is expressed at abnormally low levels in patients with hereditary hemochromatosis. previous work by the group and other Vaulont had shown that high iron levels trigger the liver to hepcidin and high hepcidin lowers the amount of iron in the body. In their current paper, published online this week by Nature Genetics Vaulont, Gaël Nicolas postdoctoral researcher, and colleagues tested the importance of the low production of hepcidin in hereditary hemochromatosis. They treated mice, which like humans with the disease had defective copies of HFE gene by adding a gene for hepcidin. Mice without the added gene showed the accumulation of iron toxicity characteristic of the disease, but the livers of mice with the transgene showed "no iron accumulation whatsoever," said Vaulont. And that, she says, means a lack of hepcidin really causes hereditary hemochromatosis.
"It is a very interesting document and important," said Hal Drakesmith, a molecular biologist at the Weatherall Institute of Molecular Medicine in Oxford, UK It is appropriate that hepcidin could "in theory" provide treatment . of hereditary hemochromatosis That would be a dramatic step beyond the current treatment of choice - old but effective -. from bleeding, periodic removal of the patient's blood to remove excess iron
Related Sites
the CDC page on iron overload and hemochromatosis
the American Society hemochromatosis
hemochromatosis National digestive diseases information Clearinghouse
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