Serum calcium-independent phospholipase A2 activity in bipolar affective disorder.
OBJECTIVE
Phospholipases A2 (PLA2) are a family of enzymes involved in membrane phospholipid metabolism and cell signalling. The gene encoding one form, type VI calcium-independent phospholipase A2, is located in a region of DNA that may contain a gene important in the aetiology of psychosis. Moreover, the activity of calcium-independent PLA2 is reported to be elevated in the blood and brain of patients with schizophrenia. In this study we determined whether a similar change takes place in patients with bipolar disorder with and without a history of psychosis.


METHODS
Serum calcium-independent and -dependent PLA2 activities were determined in 24 patients with bipolar I disorder.


RESULTS
Serum calcium-independent and -dependent PLA2 activities in bipolar cases did not differ significantly from that in healthy volunteers (HVs). However, calcium-independent PLA2 activity was significantly (p < 0.05) higher in patients with a history of psychosis compared with those with no history of psychosis (by 55%) or to HVs (by 31%).


CONCLUSIONS
Our data suggest that a subset of bipolar I disorder patients with a history of psychosis have elevated calcium-independent PLA2 activity. Given that this enzyme activity is also increased in schizophrenia, elevated rates of phospholipid turnover mediated by the enzyme could represent a common biochemical feature of psychotic illness.
Ross
Brian M
BM
Northern Ontario School of Medicine, Lakehead University, Thunder Bay, ON, Canada. brian.ross@normed.ca
Hughes
Bronwen
B
Kish
Stephen J
SJ
Warsh
Jerry J
JJ
D000328:Adult; D001714:Bipolar Disorder / Q000097:blood*; D002118:Calcium / Q000097:blood*; D002462:Cell Membrane / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D010741:Phospholipases A / Q000097:blood*; D054467:Phospholipases A2; D010743:Phospholipids / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology
D010743:Phospholipids; D010741:Phospholipases A; D054467:Phospholipases A2; D002118:Calcium