N-acetyl-aspartate levels reduced in first-episode schizophrenia patients
MedWire News: Results from a Japanese study suggest that patients with first-episode schizophrenia have reduced levels of the metabolite N-acetyl-aspartate (NAA) in certain brain areas, as well as reduced serum levels of 3-methoxy-4-hydroxyphenylglycol (MHPG).
"NAA is located almost exclusively in neurons, and reductions in NAA levels are considered not only as markers of neuronal loss, but also of the level of neuronal function and mitochondrial activity," explain R Yoshimura and team from the University of Occupational and Environmental Health in Kitakyushu, Japan.
To investigate levels of NAA in first-episode schizophrenia patients, the researchers recruited 18 patients with the disorder, aged 13-52 years, and 18 gender- and age-matched controls without a history of mental illness.
They also assessed the participants' serum levels of brain-derived neurotrophic factor (BDNF), which plays a crucial role in the development, regeneration, survival, and maintenance of neural function, and plasma levels of catecholamine metabolites MHPG and homovanillic acid (HVA).
All of the participants supplied blood samples and underwent magnetic resonance spectroscopy of the brain, with regions of interest being the frontal lobe, the left basal ganglia, and the parieto-occipital lobe.
Analysis of the results revealed that first-episode schizophrenia patients had significantly lower levels of NAA in the left basal ganglia and the parieto-occipital lobe than controls. But there was no significant difference between the groups regarding NAA levels in the frontal lobe.
There was also no difference between the groups regarding serum BDNF and plasma HVA levels.
However, plasma MHPG levels were significantly reduced in first-episode schizophrenia patients compared with controls.
The team also notes in the journal European Psychiatry that there was a significant positive correlation between NAA levels in the left basal ganglia and plasma MHPG in all of the participants.
"The most important finding of the present study was that NAA levels in the left basal ganglia and the parieto-occipital lobe were significantly reduced in the first-episode psychosis of patients with schizophrenia," Yoshimura and colleagues conclude.
They add: "These results suggest that a degeneration of noradrenergic neurons might be associated with the initial progression of schizophrenia."
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By Mark Cowen