Role of duodenal iron transporters and hepcidin in patients with alcoholic liver disease

Abstract

Patients with alcoholic liver disease (ALD) often display disturbed iron indices. Hepcidin, a key regulator of iron metabolism, has been shown to be down-regulated by alcohol in cell lines and animal models. This down-regulation led to increased duodenal iron transport and absorption in animals. In this study, we investigated gene expression of duodenal iron transport molecules and hepcidin in three groups of patients with ALD (with anaemia, with iron overload and without iron overload) and controls. Expression of DMT1, FPN1, DCYTB, HEPH, HFE and TFR1 was measured in duodenal biopsies by using real-time PCR and Western blot. Serum hepcidin levels were measured by using ELISA. Serum hepcidin was decreased in patients with ALD. At the mRNA level, expressions of DMT1, FPN1 and TFR1 genes were significantly increased in ALD. This pattern was even more pronounced in the subgroups of patients without iron overload and with anaemia. Protein expression of FPN1 paralleled the increase at the mRNA level in the group of patients with ALD. Serum ferritin was negatively correlated with DMT1 mRNA. The down-regulation of hepcidin expression leading to up-regulation of iron transporters expression in the duodenum seems to explain iron metabolism disturbances in ALD. Alcohol consumption very probably causes suppression of hepcidin expression in patients with ALD.

Keywords: DCYTB; DMT1; FPN1; HEPH; HFE; TFR1; alcoholic liver disease; gene expression; hepcidin; iron.

Fig. 1

Gene expression of the analysed molecules in controls and patients with alcoholic liver disease (ALD). (A) mRNA expression of DMT1, FPN1, DCYTB, HEPH, TFR1 and HFE. (B) Protein expression of DMT1, FPN1, DCYTB and HEPH. (C) Western blot analysis of DMT1, FPN1, DCYTB, HEPH and actin (loading control). Results are depicted as means ± SEM. Statistically significant differences as compared with the control group are indicated by * P < 0.05, ** P < 0.01 and *** P < 0.001.

Fig. 2

Gene expression of the analysed molecules in controls, patients with alcoholic liver disease without iron overload (ALD without overload), with iron overload (ALD overloaded), and anaemia (ALD anaemia). (A) mRNA expression of DMT1, (B) FPN1, (C) DCYTB, (D) HEPH, (E) TFR1, (F) HFE. (G) Protein expression of DMT1, (H) FPN1, (I) DCYTB, (J) HEPH. Results are depicted as means ± SEM. Statistically significant differences are indicated by *P < 0.05, ** P < 0.01 and *** P < 0.001.

Fig. 3

Serum hepcidin levels (A) in controls and patients with alcoholic liver disease (ALD) (B) in controls, patients with alcoholic liver disease without iron overload (ALD without overload) and anaemia (ALD anaemia). Results are depicted as means ± SEM. Statistically significant differences as compared with the control group are indicated by * P < 0.05, ** P < 0.01 and *** P < 0.001.