Figure 6.

Influence of extracellular iron and hepcidin on transverse relaxation rates in human monocytes. To examine the influence of extracellular iron and hepcidin, THP-1 cells were cultured in the absence (−Fe) or in the presence of (+Fe) iron-supplemented medium containing 25 µM ferric nitrate for 7 days. These samples were treated with 200 ng/mL hepcidin for the last 24 h of culturing. Cells were harvested either immediately or 1 (1 h-Fe), 2 (2 h-Fe), 4 (4 h-Fe) and 24 (24 h-Fe) hours after removal of extracellular iron supplementation. Furthermore, these samples were treated with 200 ng/mL of hepcidin for up to 24 h before the harvest. Two-way ANOVA indicates significant changes between samples treated in the presence and absence of hepcidin. Both R₂* (A) and R₂’ (C) relaxation rates increase significantly in the presence of iron supplement and hepcidin, with a significant decrease within an hour of iron supplementation withdrawal. The irreversible component R₂ (B) is not significantly influenced by hepcidin. n = 3–4, * p < 0.05, ** p < 0.01.