Differential changes in apolipoprotein E in schizophrenia and bipolar I disorder

Background This study extends an initial finding of increased levels of apoE in Brodmann’s area (BA) 9 from subjects with schizophrenia to determine if apoE is altered in other brain regions and in brains from subjects with bipolar I disorder (BID). Methods ApoE was quantified apoE in BA 9, 10, 40, 46 and caudate putamen from control (n = 18), schizophrenic (n = 19) and BID (n = 8) subjects using Western blotting. Results In schizophrenia, there was increased apoE in BA9 (mean ± SEM: schizophrenia 3.8 ± .18 vs. control 3.2 ± .19) and BA46 (schizophrenia 2.7 ± .26 vs. control 1.6 ± .20). In BID, increased levels of the apolipoprotein were detected in the caudate putamen (BID 3.3 ± .44 vs. control 2.4 ± .19) and BA9 (BID 4.0 ± .27 vs. control 3.2 ± .19) with a decrease in apoE being measured in BA10 (BID 1.6 ± .16 vs. control 3.9 ± .53). Conclusions This study has shown disease specific, regionally discrete changes in levels of apoE in brain obtained post mortem from schizophrenic and BID subjects. Our data adds weight to the hypothesis that changes in the levels of apolipoproteins may be involved in the pathologies of schizophrenia and bipolar disorder.