Deferasirox reduces iron overload in a murine model of juvenile hemochromatosis

Exp Biol Med (Maywood). 2009 May;234(5):492-503. doi: 10.3181/0811-RM-337. Epub 2009 Feb 20.

Abstract

Mutations in hemojuvelin (HJV) cause severe juvenile hemochromatosis, characterized by iron loading of the heart, liver, and pancreas. Knockout (KO) mice lacking HJV (Hjv-/-) spontaneously load with dietary iron and, therefore, present a model for hereditary hemochromatosis (HH). In HH, iron chelation may be considered in noncandidates for phlebotomy. We examined the effects of deferasirox, an oral chelator, in Hjv-/- mice. Hepatic, cardiac, splenic, and pancreatic iron were determined by measuring elemental iron and scoring histological sections. Heart and liver iron levels were also determined repeatedly by quantitative R2* magnetic resonance imaging (MRI). The time course of iron loading without intervention was followed from Week 8 of age (study start) to Week 20, when once-daily (5x/week) deferasirox was administered, to Week 28. At 8 weeks, liver iron of KO mice was already markedly elevated versus wild-type mice (P<0.001) and reached a plateau around Week 14. In contrast, Week 8 cardiac and pancreatic iron levels were similar in both KO and wild-type mice and, compared with the liver, showed a delayed but massive iron loading up to Week 20. Contrary to the liver, heart, and pancreas, the KO mice spleen had lower iron content versus wild-type mice. In Hjv-/- mice, liver and heart iron burden was effectively reduced with deferasirox 100 mg/kg (P<0.05). Although deferasirox was less efficacious at this dose in the pancreas, over the observed time period, a clear trend toward reduced organ iron load was noted. There was no noticeable effect of deferasirox upon splenic iron in Hjv-/- mice. Quantitative R2* MRI demonstrated the ability to assess iron concentrations in the liver and myocardial muscle accurately and repetitively. Hepatic (R=0.86; P=3.2*10(-12)) and delayed myocardial (R=0.81; P=2.9*10(-10)) iron accumulation could be followed noninvasively with high agreement to invasive methods.

MeSH terms

  • Animals
  • Benzoates / pharmacology*
  • Benzoates / therapeutic use
  • Deferasirox
  • Disease Models, Animal
  • Drug Evaluation, Preclinical
  • GPI-Linked Proteins
  • Hemochromatosis / drug therapy*
  • Hemochromatosis / genetics
  • Hemochromatosis Protein
  • Humans
  • Iron / metabolism*
  • Iron Chelating Agents / pharmacology*
  • Iron Chelating Agents / therapeutic use
  • Magnetic Resonance Imaging
  • Membrane Proteins / genetics
  • Mice
  • Mice, Knockout
  • Organ Specificity
  • Triazoles / pharmacology*
  • Triazoles / therapeutic use

Substances

  • Benzoates
  • GPI-Linked Proteins
  • HJV protein, mouse
  • Hemochromatosis Protein
  • Iron Chelating Agents
  • Membrane Proteins
  • Triazoles
  • Iron
  • Deferasirox