Duodenal expression of a putative stimulator of Fe transport and transferrin receptor in anemia and hemochromatosis.

BACKGROUND & AIMS: Stimulator of Fe Transport (SFT) and transferrin receptor (TfR) are proteins involved in iron transport. This study evaluated iron metabolism protein expression in duodenal biopsy specimens from controls and patients with abnormal iron metabolism.

METHODS

Twelve controls, 8 patients with iron deficiency anemia, 7 with HFE-related hemochromatosis, and 6 with non-HFE-related iron overload were studied. Immunohistochemistry was performed on duodenal biopsy specimens with anti-TfR and anti-SFT antibodies which recognize a putative stimulator of Fe transport of ~80 kilodaltons.

RESULTS

In controls, the putative stimulator of Fe transport was expressed in the middle and distal part of the villi in the subapical cytoplasmatic region. Its expression increased in anemics and, to a lesser degree, in HFE-related hemochromatotics, whereas it was reduced in patients with non-HFE-related iron overload. TfR expression showed a crypt-to-tip gradient in controls, but not in anemics, in whom it was uniformly overexpressed. TfR expression was intermediate in HFE-related hemochromatotics and similar to controls in non-HFE-related iron overload.

CONCLUSIONS

Expression of the putative stimulator of Fe transport and TfR increases in iron deficiency. Increased expression of both proteins is present only in HFE-related hemochromatotics suggesting that other factors may be involved in determining non-HFE-related iron overload phenotype.