The study's hypothesis is that HD with large pore dialyzers remove to the dialysate iron which is bound to potentially dialyzable ligands, after it's release from intravenous iron compound administered during hemodialysis.

Most hemodialysis(HD) patients receive during HD intravenous iron compounds, which are composed of an iron core and a sugar polymer shell.

A small percentage of iron from the iron compound is released to the plasma, and may be associated with increased oxidative stress and protein oxidation. The study's hypothesis is that HD with large pore dialyzers may remove to the dialysate iron which is bound to potentially dialyzable ligands, after it's release from intravenous iron compound administered during hemodialysis.

Ligand-bound iron removal is also hypothesized to be affected by dialysate calcium and bicarbonate concentrations, which may affect iron-ligand binding.

Study Specific aims are:

To evaluate

1. Iron removal assessing dialysate iron levels.
2. Effect of iron removal and it's associated experimental conditions on patient status, assessing plasma AOPP levels and inflammation related parameters

Study include 3 parts

1. Comparing large to small pore dialyzers

   (To achieve baseline uniform conditions, patients will be on uniform dialysate bicarbonate and calcium concentrations of 33 mEq/L and 3 mEq/L,respectively, using large pore dialyzers during this part, besides the 2 HD sessions evaluating low pore dialyzers)

   and after few week break

   Using large pore dialyzers to compare

2. Low to high dialysate bicarbonate concentration (using uniform dialysate calcium concentrations of 3 mEq/L)

   and after few week break

3. Low to high dialysate calcium concentrations concentration (using uniform dialysate bicarbonate of 33 mEq/L)

In each part, patients will be first evaluated in HD without IV iron administration, which will serve as a control for evaluation after a week in HD with IV iron administration.

In each part, patients will be randomized to start either with one of the 2 experimental conditions, and after 1 week without evaluation will cross-over to the other experimental condition.

Patients may participate in 1,2 or the 3 parts of study depending on their will and condition.

Inclusion Criteria:

• Chronic hemodialysis patients

Exclusion Criteria:

• Acute disease (infection, thrombosis, ischemia, bleeding) Hepatitis B, Hepatitis C or HIV
• Intravenous iron administration or packed red cell transfusion in the last 3 weeks prior to the study
• Refusal to comply with limitations in fat containing food during HD with plasma sampling for AOPP evaluation