title: Adiponectin and membrane fluidity of erythrocytes in normotensive and hypertensive men.
abstract: OBJECTIVE
  Abnormalities in physicochemical properties of the cell membranes may underlie the defects that are strongly linked to hypertension. Recent evidence indicates that adiponectin may have protective effects against cardiovascular diseases. The purpose of the present study was to assess the possible link between plasma adiponectin and membrane fluidity in normotensive (NT) and hypertensive (HT) men.
  
  
  METHODS
  We measured the membrane fluidity (a reciprocal value of membrane microviscosity) of erythrocytes in NT and HT men by using an electron paramagnetic resonance and spin-labeling method.
  
  
  RESULTS
  The order parameter (S) for the spin label agent (5-nitroxide stearate) and the peak height ratio (h0/h(-1)) for 16-nitroxide stearate in the electron paramagnetic resonance spectra of erythrocytes were significantly higher in HT men than in NT men, indicating that membrane fluidity of erythrocytes was decreased in HT men compared with NT men. Both of plasma adiponectin and nitric oxide (NO) metabolite levels were significantly lower in HT men than in NT men. The plasma adiponectin levels were correlated with plasma NO metabolites. The S and the h0/h(-1) of erythrocytes were inversely correlated with the plasma adiponectin and NO metabolite levels, indicating that the decreased membrane fluidity of erythrocytes was associated with hypoadiponectinemia and reduced plasma NO metabolites.
  
  
  CONCLUSIONS
  The results of the present study demonstrated that plasma adiponectin levels were lower in HT men than in NT men and that hypoadiponectinemia was associated with decreased membrane fluidity of erythrocytes. The finding suggests that adiponectin may be linked to the rheologic behavior of the erythrocytes and the microcirculation in men, at least in part, by the NO-dependent mechanism.
authors.affiliation: Division of Cardiology, Department of Medicine, Wakayama Medical University, Kimiidera 811-1, Wakayama 641-8509, Japan. tsudak@mail.wakayama-med.ac.jp
authors.forename: Kazushi
authors.initials: K
authors.lastname: Tsuda
mesh_terms: D052242:Adiponectin / Q000097:blood*; D016022:Case-Control Studies; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D004910:Erythrocyte Membrane / Q000737:chemistry*; D006801:Humans; D006973:Hypertension / Q000097:blood*; D008297:Male; D008560:Membrane Fluidity; D008875:Middle Aged; D009569:Nitric Oxide / Q000097:blood / Q000378:metabolism
chemical_list: D052242:Adiponectin; D009569:Nitric Oxide