Liver iron and serum ferritin levels are misleading for estimating cardiac, pancreatic, splenic and total body iron load in thalassemia patients: factors influencing the heterogenic distribution of excess storage iron in organs as identified by MRI T2*

Toxicol Mech Methods. 2013 Jan;23(1):48-56. doi: 10.3109/15376516.2012.727198.

Abstract

A comparative assessment of excess storage iron distribution in the liver, heart, spleen and pancreas of β-thalassemia major (β-ΤΜ) patients has been carried out using magnetic resonance imaging (MRI) relaxation times T2*. The β-ΤΜ patients (8-40 years, 11 males, 9 females) had variable serum ferritin levels (394-5603 μg/L) and were treated with deferoxamine (n = 10), deferiprone (n = 5) and deferoxamine/deferiprone combination (n = 5). MRI T2* assessment revealed that excess iron is not proportionally distributed among the organs but is stored at different concentrations in each organ and the distribution is different for each β-ΤΜ patient. There is random variation in the distribution of excess storage iron from normal to severe levels in each organ among the β-ΤΜ patients by comparison to the same organs of ten normal volunteers. The correlation of serum ferritin with T2* was for spleen (r = -0.81), liver (r = -0.63), pancreas (r = -0.33) and none with heart. Similar trend was observed in the correlation of liver T2* with the T2* of spleen (r = 0.62), pancreas (r = 0.61) and none with heart. These studies contradict previous assumptions that serum ferritin and liver iron concentration is proportional to the total body iron stores in β-ΤΜ and especially cardiac iron load. The random variation in the concentration of iron in the organs of β-ΤΜ patients appears to be related to the chelation protocol, organ function, genetic, dietary, pharmacological and other factors. Monitoring of the iron load for all the organs is recommended for each β-ΤΜ patient.

MeSH terms

  • Adolescent
  • Adult
  • Body Burden
  • Child
  • Deferiprone
  • Deferoxamine / therapeutic use
  • Drug Therapy, Combination
  • Female
  • Ferritins / blood*
  • Humans
  • Iron / analysis
  • Iron / metabolism*
  • Iron Chelating Agents / therapeutic use
  • Iron Overload / drug therapy
  • Iron Overload / etiology
  • Iron Overload / metabolism
  • Liver / chemistry
  • Liver / metabolism*
  • Magnetic Resonance Imaging
  • Male
  • Myocardium / chemistry
  • Myocardium / metabolism*
  • Pancrelipase / chemistry
  • Pancrelipase / metabolism*
  • Pyridones / therapeutic use
  • Spleen / chemistry
  • Spleen / metabolism*
  • Young Adult
  • beta-Thalassemia / complications
  • beta-Thalassemia / drug therapy
  • beta-Thalassemia / metabolism*

Substances

  • Iron Chelating Agents
  • Pyridones
  • Deferiprone
  • Pancrelipase
  • Ferritins
  • Iron
  • Deferoxamine