title: Acute Free-Iron Exposure Does Not Explain the Impaired Haemorheology Associated with Haemochromatosis.
abstract: BACKGROUND
  Given the severity of the current imbalance between blood donor supply and recipient demand, discarded blood drawn from the routine venesections of haemochromatosis (HFE-HH) patients may serve as a valuable alternative source for blood banks and transfusion. We investigated whether functional or biochemical differences existed between HFE-HH and control blood samples, with particular focus upon the haemorheological properties, to investigate the viability of venesected blood being subsequently harvested for blood products.
  
  
  METHODS
  Blood samples were collected from HFE-HH patients undergoing venesection treatment (n = 19) and healthy volunteers (n = 8). Moreover, a second experiment investigated the effects of a dose-response of iron (0, 40, 80, 320 mM FeCl3) on haemorheology in healthy blood samples (n = 7). Dependent variables included basic haematology, iron status, haematocrit, red blood cell (RBC) aggregation (native and standardised haematocrit) and "aggregability" (RBC tendency to aggregate in a standard aggregating medium; 0.4 L/L haematocrit in a Dx70), and RBC deformability.
  
  
  RESULTS
  Indices of RBC deformability were significantly decreased for HFE-HH when compared with healthy controls: RBC deformability was significantly decreased at 1-7 Pa (p < 0.05), and the shear stress required for half maximal deformability was significantly increased (p < 0.05) for HFE-HH. RBC aggregation in plasma was significantly increased (p < 0.001) for HFE-HH, although when RBC were suspended in plasma-free Dx70 no differences were detected. No differences in RBC deformability or RBC aggregation/aggregability were detected when healthy RBC were incubated with varying dose of FeCl3.
  
  
  CONCLUSIONS
  HFE-HH impairs the haemorheological properties of blood; however, RBC aggregability was similar between HFE-HH and controls when cells were suspended in a plasma-free medium, indicating that plasma factor(s) may explain the altered haemorheology in HFE-HH patients. Acute exposure to elevated iron levels does not appear (in isolation) to account for these differences. Further consideration is required prior to utilising routine venesection blood for harvesting RBC concentrates due to the potential risk of microvascular disorders arising from impaired haemorheology.
authors.affiliation: School of Allied Health Sciences, Griffith University, Queensland, Australia.
authors.forename: Antony P
authors.initials: AP
authors.lastname: McNamee
authors.affiliation: Menzies Health Institute Queensland, Griffith University, Queensland, Australia.
authors.forename: Surendran
authors.initials: S
authors.lastname: Sabapathy
authors.affiliation: School of Medical Sciences, Griffith University, Queensland, Australia.
authors.forename: Indu
authors.initials: I
authors.lastname: Singh
authors.affiliation: School of Allied Health Sciences, Griffith University, Queensland, Australia.
authors.forename: Jarod
authors.initials: J
authors.lastname: Horobin
authors.affiliation: School of Medical Sciences, Griffith University, Queensland, Australia.
authors.forename: Janelle
authors.initials: J
authors.lastname: Guerrero
authors.affiliation: Menzies Health Institute Queensland, Griffith University, Queensland, Australia.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Simmonds
mesh_terms: D000368:Aged; D001782:Blood Donors; D001809:Blood Viscosity; D016022:Case-Control Studies; D004903:Erythrocyte Aggregation; D004907:Erythrocyte Deformability; D004912:Erythrocytes / Q000187:drug effects / Q000502:physiology; D005260:Female; D006432:Hemochromatosis / Q000097:blood*; D006801:Humans; D007501:Iron / Q000097:blood* / Q000494:pharmacology; D008297:Male; D008875:Middle Aged
chemical_list: D007501:Iron