Angiotensin II alters the expression of duodenal iron transporters, hepatic hepcidin, and body iron distribution in mice
2015
Tajima, Soichiro | Ikeda, Yasumasa | Enomoto, Hideaki | Imao, Mizuki | Horinouchi, Yuya | Izawa-Ishizawa, Yuki | Kihira, Yoshitaka | Miyamoto, Licht | Ishizawa, Keisuke | Tsuchiya, Koichiro | Tamaki, Toshiaki
PURPOSE: Angiotensin II (ANG II) has been shown to affect iron metabolism through alteration of iron transporters, leading to increased cellular and tissue iron contents. Serum ferritin, a marker of body iron storage, is elevated in various cardiovascular diseases, including hypertension. However, the associated changes in iron absorption and the mechanism underlying increased iron content in a hypertensive state remain unclear. METHODS: The C57BL6/J mice were treated with ANG II to generate a model of hypertension. Mice were divided into three groups: (1) control, (2) ANG II-treated, and (3) ANG II-treated and ANG II receptor blocker (ARB)-administered (ANG II–ARB) groups. RESULTS: Mice treated with ANG II showed increased serum ferritin levels compared to vehicle-treated control mice. In ANG II-treated mice, duodenal divalent metal transporter-1 and ferroportin (FPN) expression levels were increased and hepatic hepcidin mRNA expression and serum hepcidin concentration were reduced. The mRNA expression of bone morphogenetic protein 6 and CCAAT/enhancer-binding protein alpha, which are regulators of hepcidin, was also down-regulated in the livers of ANG II-treated mice. In terms of tissue iron content, macrophage iron content and renal iron content were increased by ANG II treatment, and these increases were associated with reduced expression of transferrin receptor 1 and FPN and increased expression of ferritin. These changes induced by ANG II treatment were ameliorated by the administration of an ARB. CONCLUSIONS: Angiotensin II (ANG II) altered the expression of duodenal iron transporters and reduced hepcidin levels, contributing to the alteration of body iron distribution.
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