title: Reduced activities of phospholipases A2 in platelets of drug-naïve bipolar disorder patients.
abstract: OBJECTIVE
  Phospholipases A2 (PLA2 ) comprise a family of hydrolytic enzymes that cleave membrane phospholipids and play a key role in cellular homeostasis. Alterations in enzymatic activity have been hypothesized in bipolar disorder (BD). Recent studies suggest that PLA2 activity in platelets may reflect PLA2 activity in the brain. The aim of this study was to determine PLA2 activity in platelets of BD patients.
  
  
  METHODS
  We determined the activity of PLA2 subtypes [extracellular, calcium-dependent PLA2 (sPLA2 ), intracellular, calcium-dependent PLA2 (cPLA2 ), and intracellular, calcium-independent PLA2 (iPLA2 )] by a radioenzymatic method in platelets from 20 patients with BD (15 drug-naïve and five drug-free) and from 16 age- and gender-matched healthy controls.
  
  
  RESULTS
  We found that iPLA2 , cPLA2 , and sPLA2 activities were lower in drug-naïve patients with BD when compared to the control group (p = 0.017, p < 0.001, and p < 0.001, respectively).
  
  
  CONCLUSIONS
  Reduced PLA2 activity at the early stage of BD may disrupt brain function and increase the risk for the disease. Moreover, epidemiological studies show that patients with BD have a fivefold increased risk for developing Alzheimer's disease. Because patients with Alzheimer's disease also have reduced PLA2 activity, the present finding of reduced PLA2 in the BD group may be related to the risk factor for these individuals developing Alzheimer's disease in advanced age.
authors.affiliation: Laboratory of Neuroscience, Department and Institute of Psychiatry, Faculty of Medicine, University of Sao Paulo, Sao Paulo, Brazil.
authors.forename: Eliza Hiromi
authors.initials: EH
authors.lastname: Ikenaga
authors.forename: Leda Leme
authors.initials: LL
authors.lastname: Talib
authors.forename: Aline Siqueira
authors.initials: AS
authors.lastname: Ferreira
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Machado-Vieira
authors.forename: Orestes Vicente
authors.initials: OV
authors.lastname: Forlenza
authors.forename: Wagner F
authors.initials: WF
authors.lastname: Gattaz
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000097:blood / Q000175:diagnosis; D001792:Blood Platelets / Q000201:enzymology*; D001921:Brain / Q000201:enzymology*; D002118:Calcium / Q000378:metabolism; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D008297:Male; D054467:Phospholipases A2 / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism; D011569:Psychiatric Status Rating Scales; D012307:Risk Factors
chemical_list: D010743:Phospholipids; D054467:Phospholipases A2; D002118:Calcium
keywords: Alzheimer's disease; biomarkers; bipolar disorder; phospholipases A2; platelets