Analysis of the Modulation of Serum Hepcidin Level in Response to Iron Oral Intake: Potential Interest for the Differential Diagnosis Between Ferroportin Disease and Dysmetabolic Hepatosiderosis.
Analysis of the Modulation of Serum Hepcidin Level in Response to Iron Oral Intake: Potential Interest for the Differential Diagnosis Between Ferroportin Disease and Dysmetabolic Hepatosiderosis.
The diagnosis of iron overload is a common problem. It is important to optimize the diagnosis
 to ensure support for patients and their relatives especially regarding genetic disease.

 Iron overload revealed by a high level of serum ferritin and confirmed by the presence of an
 excessive amount of iron in the liver is a frequent situation. In a lot of case there is no
 increase in serum iron and transferrin saturation. This situation may arise in particular in
 patients with:

 -  a genetic iron overload related to mutation in the ferroportine gene, leading to a
 ferroportin disease. The diagnosis is based on the sequencing of the gene,

 -  a dysmetabolic hepatosiderosis, the most frequent situation , where iron overload is
 associated with abnormalities in the metabolism of carbohydrates and fats, whereas no
 genetic cause is identified.

 However, patients often have similar biological signs and despite the implementation of
 strict algorithm regarding the diagnostic procedure, it appears that a large number of
 patients are tested for the mutation in the ferroportin gene, and that mutation is not found
 in most cases. It is therefore essential to optimize the diagnosis process by introducing
 additional criteria.

 The investigators' hypothesis, based on the known elements, is that the response to a single
 dose of iron will modulate differently the iron parameters measured in serum, including
 hepcidin level which controls iron metabolism and metals associated with iron. This could be
 helpful for diagnosis procedure in patients with ferroportin disease or dysmetabolic
 hepatosiderosis.
The quantification of serum hepcidin level is a potential method of investigation in iron
 metabolism disorders. However, apart from some extreme situations, the assay achieved solely
 is not helpful. This is due to the varying levels encountered from one subject to another for
 the same disease. This is related to the facts that values considered to be normal cover a
 wide range and that a value obtained for a given patient at a given time, can be influenced
 by many factors.

 It has been reported that a a single oral iron dose induced an increase of serum hepcidin
 level in healthy subjects which is abolished in subjects with genetic hemochromatosis linked
 to insufficient hepcidin expression related to mutations in the HFE or TFR2 genes.

 In patients with a dysmetabolic hepatosiderosis, it was suggested that the expected
 hepcidinemia increase found after an iron intake was altered, likely due to a slight
 inflammatory signal responsible for hepcidin induction.

 The investigators hypothesize that a dynamic response of iron parameters, including
 modulation of hepcidin level, to an iron intake will allow to discriminate patients with
 ferroportin disease or dysmetabolic hepatosiderosis, situations whose clinicobiological
 presentation is often confusing.

 Thus, the three objectives in this study will be :

 1. To define pharmacokinetic characteristics of serum hepcidin in response to iron oral
 intake and to determine the ability of this pharmacokinetic to discriminate dysmetabolic
 hepatosiderosis and ferroportin disease.

 2. To correlate amplitude of this response to the iron parameters modulation

 3. To correlate amplitude of this response to the concentration of divalent cations whose
 metabolism uses common genes to those involved in iron metabolism.
Inclusion Criteria for patients:

 -  Man or woman older than 18 years

 -  Subject having a liver iron overload greater than or equal to 100 umol /g dry liver
 weight, confirmed by MRI (done performed with body antenna and complete deactivation
 of the surface antenna) and / or by biochemical assay on liver biopsy, and related to
 dysmetabolic hepatosiderosis or ferroportin disease.

 -  The ferroportin disease will be retained when patients will present an
 hyperferritinemia without elevated transferrin saturation and a heterozygote
 mutation in the gene encoding ferroportin.

 -  A dysmetabolic hepatosiderosis will be retained following the usual diagnostic
 investigation including sequencing of the gene for ferroportin (mutation proven
 negative), if patients do not show any other cause of iron overload and
 hyperferritinemia is not related to excessive alcohol intake, non-metabolic liver
 cytolysis (hepatitis C virus, wilson, autoimmune hepatitis, ...), hemolysis, or
 inflammatory syndrome.

 -  Status towards the iron-depletive treatment : either no venesection performed
 (Dysmetabolic HepatoSiderosis and Ferroportin disease groups) or attack iron depletive
 treatment completed (Treated Dysmetabolic Hepatosiderosis and Treated Ferroportin
 Disease groups) with ferritin level less than 100 ng / ml, without anemia and with no
 venesection in the two last months.

 -  Having given a free and informed consent in writing

 -  Affiliate to the social security system.

 Exclusion Criteria for patients:

 -  Alcohol consumption greater than 30g/d

 -  Chronic inflammatory disease.

 -  HIV, HCV or HBV Infection.

 -  Blood donation in the last three months.

 -  Infection during the previous seven days before testing

 -  Staying in altitude (>1500 m) dating less than 2 months

 -  Night occupation or shift work.

 -  Pregnancy

 -  Exclusion period in the national register of persons suitable for biomedical research.

 -  Protected adults (judicial protection, guardianship and trusteeship) and persons
 deprived of liberty

 Inclusion criteria for healthy volunteers:

 -  Man or woman older than 18 years.

 -  Body Mass Index between 18 and 25 kg/m².

 -  Non smoker or quit smoking for more than 6 months

 -  Examen clinique normal. Normal clinical examination

 -  Normal ECG.

 -  Normal values for routine laboratory tests : serum iron, tranferrin saturation, CBC,
 ferritin, blood cell count C-reactive protein, AST, ALT, GGT, HDL and LDL cholesterol,
 triglycerides.

 -  Having given a free and informed consent in writing

 -  Affiliate or beneficiary to the social security system.

 Exclusion criteria for healthy volunteers :

 -  Progressive and/or chronic disease.

 -  Infection during the previous seven days before testing

 -  Drug use under 6 months.

 -  Alcohol consumption greater than 30g/d

 -  Medication ongoing or stopped from less than a week (except contraceptives).

 -  History of blood transfusion or martial treatment.

 -  Staying in altitude (>1500 m) dating less than 2 months

 -  Night occupation or shift work.

 -  Known infection by hepatitis B or C.

 -  Positive serology for HIV.

 -  Blood donation in the last three months.

 -  Pregnancy.

 -  Exclusion period in the national register of persons suitable for biomedical research.

 -  Protected adults (judicial protection, guardianship and trusteeship) and persons
 deprived of liberty.