title: The positive relationship of serum paraoxonase-1 activity with apolipoprotein E is abrogated in metabolic syndrome.
abstract: BACKGROUND
  High density lipoproteins (HDL) contain paraoxonase-1 (PON-1), which has strong anti-oxidative properties. Apolipoprotein E (apoE) may enhance PON-1 activity in vitro, but the extent to which PON-1 activity is determined by circulating apoE levels is unknown. Here we determined relationships of serum PON-1 activity with apoE in subjects without and with metabolic syndrome (MetS).
  
  
  METHODS
  We measured PON-1 activity (arylesterase activity), plasma apoE and serum amyloid A (SAA) in 93 subjects without and in 75 subjects with MetS (25 and 54 subjects with Type 2 diabetes mellitus (T2DM), respectively; p < 0.001).
  
  
  RESULTS
  PON-1 activity was lower in MetS (p < 0.005) coinciding lower HDL cholesterol, apoA-I (p < 0.001)) and SAA levels (p < 0.01), whereas apoE was increased in relation to higher triglycerides (p < 0.01). In subjects without MetS, PON-1 activity was correlated positively with apoE (r = 0.376, p < 0.001), but this relationship was absent in MetS subjects (r = 0.085, p = 0.47). Multiple linear regression analysis showed that the relationship of PON-1 activity with apoE was different in subjects with MetS compared to subjects without MetS (β = -0.270, p = 0.014 for the interaction between apoE and MetS), independently from age, sex, T2DM, use of glucose lowering drugs, anti-hypertensives and the inverse relation with SAA levels (p = 0.008). Of the individual MetS components, apoE only interacted with low HDL-C on PON-1 activity (β = -0.175, p = 0.074). The relationship of apoE with PON-1 activity was neither modified by T2DM (p = 0.49), nor by SAA (p = 0.79).
  
  
  CONCLUSIONS
  Higher apoE levels may confer higher PON-1 activity. The relationship of PON-I activity with total plasma apoE is apparently abrogated in MetS.
authors: Department of Endocrinology, University of Groningen, The Netherlands. r.p.f.dullaart@int.umcg.nl
authors: Robin P F
authors: RP
authors: Dullaart
authors: Arjan J
authors: AJ
authors: Kwakernaak
authors: Geesje M
authors: GM
authors: Dallinga-Thie
mesh_terms: D000368:Aged; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry; D001057:Apolipoproteins E / Q000097:blood*; D043303:Aryldialkylphosphatase / Q000097:blood*; D001786:Blood Glucose / Q000032:analysis; D002784:Cholesterol / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D003924:Diabetes Mellitus, Type 2 / Q000097:blood; D005260:Female; D005786:Gene Expression Regulation; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D008075:Lipoproteins, HDL / Q000378:metabolism; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood*; D051379:Mice; D008807:Mice, Inbred BALB C; D008875:Middle Aged; D012044:Regression Analysis; D000685:Serum Amyloid A Protein / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D001057:Apolipoproteins E; D043303:Aryldialkylphosphatase; D001786:Blood Glucose; D002784:Cholesterol; D006442:Glycated Hemoglobin; D008075:Lipoproteins, HDL; D000685:Serum Amyloid A Protein; C468406:PON1 protein, human
keywords: Apolipoprotein AI; Apolipoprotein E; HDL function; Metabolic syndrome; Paraoxonase-1 activity; Serum amyloid A