title: Roles of paraoxonase and oxidative stress in adolescents with uraemic, essential or obesity-induced hypertension.
abstract: OBJECTIVE
  Paraoxonase 1 (PON1) is associated with high-density lipoproteins in the plasma, and is capable of hydrolysing oxidized lipids and preventing the oxidation of low-density lipoproteins. Oxidative stress and the PON1 (activity and Q192R polymorphism) were analysed in adolescent patients with essential (n = 49) or obesity-induced hypertension (n = 79), uraemic patients (n = 20), and also in obese normotensive patients (n = 60) and age-matched controls (n = 57).
  
  
  METHODS
  The PON1 activity was measured via paraoxon hydrolysis. The PON1 genotype was determined by real-time PCR. The levels of oxidized and reduced glutathione, the end-products of nitric oxide, cysteine, homocysteine and lipid peroxidation in the plasma were measured and related to the PON1 status.
  
  
  RESULTS
  There were no significant differences between the patient groups and the control group in the genotype distributions and the allele frequencies of the Q192R polymorphism. The PON activity was significantly lower (p < 0.001) in the uraemic hypertensive group than in the controls. The MDA concentration was significantly higher in the uraemic hypertensive (p < 0.001) and obese hypertensive (p < 0.05) patients. The plasma NOx concentrations were significantly lower (p < 0.001) and the ratio MDA/NOx were significantly higher in all four patient groups. The GSH levels were significantly lower in the patients with hypertension (p < 0.001) and obesity-induced hypertension (p < 0.05) than in the controls, while the GSSG level (p < 0.01) and the ratio GSSG/GSH (p < 0.05) was significantly higher in the uraemic hypertensive group. The plasma homocysteine level was significantly higher (p < 0.001) in the uraemic hypertensive patients as compared with the controls.
  
  
  CONCLUSIONS
  We found no significant correlation between the biochemical parameters and neither genotypes nor enzyme activities. The PON1 status and the levels of certain biochemical parameters are independently associated with the hypertension in hypertensive and obese hypertensive patients, and the elevated levels of lipid peroxides and plasma homocysteine may contribute to the increased risk of cardiovascular complications in patients on haemodialysis.
authors.affiliation: Department of Paediatrics, Albert Szent-Györgyi Medical and Pharmaceutical Centre, University of Szeged, Szeged, Hungary. a.barath@gmail.com
authors.forename: Akos
authors.initials: A
authors.lastname: Baráth
authors.forename: Ilona
authors.initials: I
authors.lastname: Németh
authors.forename: Eszter
authors.initials: E
authors.lastname: Karg
authors.forename: Emoke
authors.initials: E
authors.lastname: Endreffy
authors.forename: Csaba
authors.initials: C
authors.lastname: Bereczki
authors.forename: Balázs
authors.initials: B
authors.lastname: Gellén
authors.forename: Ibolya
authors.initials: I
authors.lastname: Haszon
authors.forename: Sándor
authors.initials: S
authors.lastname: Túri
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D043303:Aryldialkylphosphatase / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005978:Glutathione / Q000032:analysis; D006710:Homocysteine / Q000097:blood; D006801:Humans; D006973:Hypertension / Q000209:etiology / Q000503:physiopathology*; D008054:Lipid Peroxides / Q000097:blood; D008297:Male; D009765:Obesity / Q000150:complications / Q000503:physiopathology*; D018384:Oxidative Stress / Q000502:physiology*; D011110:Polymorphism, Genetic; D006435:Renal Dialysis; D014511:Uremia / Q000503:physiopathology*
chemical_list: D008054:Lipid Peroxides; D006710:Homocysteine; D043303:Aryldialkylphosphatase; C468406:PON1 protein, human; D005978:Glutathione