title: Evidence for the presence of active paraoxonase 1 in small-dense low-density lipoprotein.
abstract: OBJECTIVE
  We have recently demonstrated the quick ex vivo transfer of paraoxonase 1 (PON1) activity from high-density lipoprotein (HDL) to small, dense low-density lipoprotein (sdLDL). We set out to assess whether sdLDL contains active PON1 in vivo.
  
  
  METHODS
  We conducted a nested case-control, proof of principle study with the Japanese healthy subjects with normal lipids (n = 23) and age and gender-paired dyslipidemic subjects (n = 17). Lipid panels, lactonase and arylesterase assays, and PON1 zymogram in the LDL and HDL subclasses were assessed.
  
  
  RESULTS
  PON1 specific activity in the high-molecular weight lipoprotein fraction corresponding to LDL migration was found in 48% of normo and in 29% of dyslipidemic Japanese subjects. This band co-localizes with apoB100 and not Lp(a) and displays a lower molecular mass than the bulk of LDL.
  
  
  CONCLUSIONS
  We provide evidence, for the first time, that native sdLDL contains up to 4% of the total PON1 activity in the serum of up to 48% of the Japanese subjects. Could the PON1-containing sdLDL represent a set of particles with a defense mechanism from oxidation and therefore its levels actually prove to be atheroprotective? If further studies confirm this contention, a zymogram of PON1 in LDL subclasses could be a functional assay that complements the current methods that only inform on the size and lipid concentration of these particles.
authors: Alejandro
authors: A
authors: Gugliucci
authors: Russell
authors: R
authors: Caccavello
authors: Kazuhiko
authors: K
authors: Kotani
authors: Satoshi
authors: S
authors: Kimura
mesh_terms: D000368:Aged; D043303:Aryldialkylphosphatase / Q000097:blood* / Q000378:metabolism*; D002265:Carboxylic Ester Hydrolases / Q000097:blood / Q000378:metabolism; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008075:Lipoproteins, HDL / Q000097:blood / Q000378:metabolism; D008077:Lipoproteins, LDL / Q000097:blood / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress
chemical_list: D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL; D002265:Carboxylic Ester Hydrolases; C020579:gluconolactonase; C019734:arylesterase; D043303:Aryldialkylphosphatase; C468406:PON1 protein, human
keywords: Atherosclerosis; Oxidative stress; Paraoxonase 1; Small-dense LDL