title: Alteration of the pro-oxidant xanthine oxidase (XO) in the thalamus and occipital cortex of patients with schizophrenia.
abstract: OBJECTIVE
  Mounting evidence shows that oxidative stress (OS) and the purine/adenosine system play a key role in the pathophysiology of schizophrenia. Lately, our group pointed out that not only antioxidants, but also the prooxidant system plays an important role in neuro-psychiatric disorders. Xanthine oxidase (XO) is an enzyme of special interest in this context, since it acts as a prooxidant, but its main product is a vastly important antioxidant, uric acid (UA). Furthermore, XO plays major part in the purine/adenosine metabolism, which has been hypothesised to play a role in schizophrenia as well.
  
  
  METHODS
  We examined the activity of XO in the striato-cortico-limbic system of schizophrenic patients (SP) and controls using a commercially available activity assay.
  
  
  RESULTS
  We found decreased activity of XO in the occipital cortex and thalamus of patients with psychosis. Furthermore, XO shows a significant positive correlation with chlorpromazine equivalents in the putamen and the temporal cortex.
  
  
  CONCLUSIONS
  Nevertheless, our results might suggest a downregulation of cellular defence mechanisms in schizophrenia in several brain regions, which could account for neuronal alterations which have been described before. This demonstrates that more research is needed to fully understand the role of the complex enzyme XO in the pathophysiology of schizophrenia.
authors.affiliation: Department of Psychiatry and Psychotherapy, RWTH University Aachen, Aachen, Germany. tmichel@ukaachen.de
authors.forename: Tanja Maria
authors.initials: TM
authors.lastname: Michel
authors.forename: Abigail Jane
authors.initials: AJ
authors.lastname: Sheldrick
authors.forename: Sybille
authors.initials: S
authors.lastname: Camara
authors.forename: Edna
authors.initials: E
authors.lastname: Grünblatt
authors.forename: Frank
authors.initials: F
authors.lastname: Schneider
authors.forename: Peter
authors.initials: P
authors.lastname: Riederer
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009778:Occipital Lobe / Q000201:enzymology* / Q000378:metabolism; D018384:Oxidative Stress; D012559:Schizophrenia / Q000201:enzymology* / Q000378:metabolism / Q000503:physiopathology; D013788:Thalamus / Q000201:enzymology* / Q000378:metabolism; D014969:Xanthine Oxidase / Q000378:metabolism* / Q000502:physiology
chemical_list: D014969:Xanthine Oxidase