Deferasirox reduces iron overload in a murine model of juvenile hemochromatosis.
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.
Nick
Hanspeter
H
Novartis Institutes for Biomedical Research, Novartis Pharma AG, Lichtstrasse 35, CH-4002, Basel, Switzerland. hanspeter.nick@novartis.com
Allegrini
Peter R
PR
Fozard
Lucy
L
Junker
Ursula
U
Rojkjaer
Lisa
L
Salie
Rishard
R
Niederkofler
Vera
V
O'Reilly
Terrence
T
D000818:Animals; D001565:Benzoates / Q000494:pharmacology* / Q000627:therapeutic use; D000077588:Deferasirox; D004195:Disease Models, Animal; D004353:Drug Evaluation, Preclinical; D058851:GPI-Linked Proteins; D006432:Hemochromatosis / Q000188:drug therapy* / Q000235:genetics; D000071020:Hemochromatosis Protein; D006801:Humans; D007501:Iron / Q000378:metabolism*; D007502:Iron Chelating Agents / Q000494:pharmacology* / Q000627:therapeutic use; D008279:Magnetic Resonance Imaging; D008565:Membrane Proteins / Q000235:genetics; D051379:Mice; D018345:Mice, Knockout; D009928:Organ Specificity; D014230:Triazoles / Q000494:pharmacology* / Q000627:therapeutic use
D001565:Benzoates; D058851:GPI-Linked Proteins; C504414:HJV protein, mouse; D000071020:Hemochromatosis Protein; D007502:Iron Chelating Agents; D008565:Membrane Proteins; D014230:Triazoles; D007501:Iron; D000077588:Deferasirox