Neuropathological similarities and differences between schizophrenia and bipolar disorder: a flow cytometric...

Area of Science:

• Neuroscience
• Psychiatry
• Cell Biology

Background:

• Schizophrenia (SCH) and bipolar disorder (BPD) are complex psychiatric conditions with suspected shared underlying neuropathology.
• Comprehensive, quantitative characterization of neuropathological differences and similarities between SCH and BPD remains limited.

Purpose of the Study:

• To quantitatively compare neuropathological features in the frontopolar cortex (FPC) and inferior temporal cortex (ITC) between patients with SCH, BPD, and healthy controls.
• To investigate cell nuclei size and density distributions as potential biomarkers for distinguishing SCH and BPD.

Main Methods:

• Utilized a rapid, quantitative flow cytometry-based cell-counting method on frozen, unfixed postmortem brain tissue.
• Measured NeuN(+) (neuronal) and olig2(+) (oligodendrocyte lineage) nuclei size and density in FPC and ITC gray matter.
• Assessed left-right asymmetry in neural nuclei densities.

Main Results:

• Both SCH and BPD groups exhibited abnormal distributions of small NeuN(+) nuclei in the ITC gray matter.
• SCH patients showed similar NeuN(+) abnormalities in the FPC, alongside a reversed left-right asymmetry in neural nuclei density.
• BPD patients displayed a reduction in olig2(+) cells in the FPC, with a distinct pattern of asymmetry compared to SCH.

Conclusions:

• While SCH and BPD share some neuropathological features, significant differences exist, particularly in the FPC.
• These region-specific neuropathological distinctions may contribute to the observed clinical and cognitive differences between schizophrenia and bipolar disorder.