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AIM: Childhood trauma (CT), abuse and neglect are commonly reported by individuals experiencing psychosis. However, there are concerns that acute psychotic symptoms, in particular delusions, may contribute to inaccurate reporting of CT. As a result, individuals experiencing psychosis may not be asked about their experiences of abuse when they are being seen in psychiatric settings. This lack of attention can directly impact on the tailoring of their clinical care. This study aimed to investigate the stability of reports of CT by young people experiencing a first psychotic episode (FEP) compared to healthy comparison subjects. METHODS: Responses of 24 young people during the acute FEP and 3 months later to items on the Childhood Trauma Questionnaire (CTQ) were compared to 30 non-psychiatric controls. All participants were aged 15 to 25 years. RESULTS: FEP participants reported higher CT than controls at both time points. Reliability analyses (interclass correlation coefficients [ICCs]) suggested strong agreement between CT reports at baseline and follow-up for FEP participants (.81) and controls (.91). Positive psychotic symptoms were unrelated to CT reports. Although the severity of CT reports fluctuated between assessments, complete retractions of severe abuse claims occurred rarely. CONCLUSIONS: The results suggest that retrospective self-report can be used to reliably assess CT in young people experiencing acute psychosis.

Alzheimer's disease is characterized by abnormal amyloid-β (Aβ) peptide accumulation beginning decades before symptom onset. An effective prophylactic treatment aimed at arresting the amyloidogenic pathway would therefore need to be initiated prior to the occurrence of Aβ pathology. The SIGMAR1 gene encodes a molecular chaperone that modulates processing of the amyloid-β protein precursor (AβPP). Fluvoxamine is a selective serotonin reuptake inhibitor and a potent SIGMAR1 agonist. We therefore hypothesized that fluvoxamine treatment would reduce Aβ production and improve cognition. We firstly investigated the impact of SIGMAR1 on AβPP processing, and found that overexpression and knockdown of SIGMAR1 significantly affected γ-secretase activity in SK-N-MC neuronal cells. We then tested the impact of fluvoxamine on Aβ production in an amyloidogenic cell model, and found that fluvoxamine significantly reduced Aβ production by inhibiting γ-secretase activity. Finally, we assessed the efficacy of long-term treatment (i.e., ∼8 months) of 10 mg/kg/day fluvoxamine in the J20 amyloidogenic mouse model; the treatment was initiated prior to the occurrence of predicted Aβ pathology. Physical examination of the animals revealed no overt pathology or change in weight. We conducted a series of behavioral tests to assess learning and memory, and found that the fluvoxamine treatment significantly improved memory function as measured by novel object recognition task. Two other tests revealed no significant change in memory function. In conclusion, fluvoxamine has a clear impact on γ-secretase activity and AβPP processing to generate Aβ, and may have a protective effect on cognition in the J20 mice.

Intracellular cobalamin (Cbl) utilization is critically dependent on its efficient transit through the lysosome and subsequent delivery to cytosol and mitochondria. We propose that age-related pathological processes may inhibit lysosomal function and impair intracellular Cbl transport. Purpose: To investigate alterations of intracellular [57Co]Cbl trafficking in subcellular organelles when lysosome function is interrupted it is essential to develop an optimal subcellular fractionation method to isolate pure lysosomes, mitochondria and cytosol. Methods: Approximately 100 million human SH-SY5Y neurons or HT1080 fibroblasts were labelled with [57Co]Cbl, homogenised using a ball-bearing homogeniser and the lysates fractionated using an Optiprep gradient and reagent kits from either Pierce or Sigma. [57Co] in each fraction was measured using a gamma counter and subcellular fractions were probed by western blotting. Results: Both protocols separated subcellular organelles to a certain extent. The Pierce method seemed to be superior, separating pure lysosomes from mitochondrial fractions without cytosol contamination. SH-SY5Y [57Co]Cbl lysosome / mitochondria / cytosol distribution was 5.2 + 0.4 / 13.2 + 0.6 / 81.6 + 0.8, respectively, and this was changed (all p < 0.01) to 54.2 + 1.9 / 7.0 + 0.9 / 35.5 + 2.7, respectively (all mean + SE, n = 3), when cells were treated for 48 h with 25 μM chloroquine (to increase lysosomal pH). Similar results were obtained using HT1080 fibroblasts. Conclusion: Development of subcellular fractionation methods provides a useful tool for investigating intracellular Cbl trafficking. This method can be adapted to study the impact of age- or pathology-related lysosomal dysfunction on intracellular [57Co]Cbl transport.

ATP-binding cassette transporter A7 (ABCA7) is expressed in the brain and has been detected in macrophages, microglia, and neurons. ABCA7 promotes efflux of lipids from cells to apolipoproteins. ABCA7 can also regulate phagocytosis and modulate processing of amyloid precursor protein (APP) to generate the Alzheimer’s disease (AD) amyloid-β (Aβ) peptide. Genome-wide association studies indicate ABCA7 SNPs confer increased risk for late-onset AD; however, the role that ABCA7 plays in the brain in the AD context is unknown. In the present study we crossed ABCA7 deficient (A7-/-) mice with J20 amyloidogenic mice to address this issue. We show that ABCA7 loss doubled insoluble Aβ levels and thioflavine-S positive plaques in the brain. This was not related to changes in APP processing (assessed by analysis of full-length APP and the APP β C-terminal fragment). Apolipoprotein E (apoE) regulates cerebral Aβ homeostasis and plaque load, however, apoE concentration was not altered by ABCA7 loss. Spatial reference memory was significantly impaired in both J20 and J20/A7-/- mice compared to wild type mice; however, there were no cognitive differences comparing J20 and J20/A7-/- mice. There were also no major differences detected in hippocampal or plaque-associated microglial/macrophage markers when J20 and J20/A7-/- mice were compared, whereas the capacity for macrophages derived from A7-/- mice to take up oligomeric Aβ was reduced by 51% compared to wild type mice. Our studies suggest ABCA7 plays a role in the regulation of Aβ homeostasis in the brain and that this may be related to altered phagocyte function.

Purpose: The aim of the present study is to establish a new gas chromatography mass spectrometry (GC-MS) method using a triple quadrupole which would allow for more sensitive quantification of changes in homocysteine, methionine and methylmalonate in small numbers of cultured cells and brain tissue. Homocysteine, methionine and methylmalonate are established markers of cobalamin deficiency. Methods: Cultured cells (1 x 106) and 5mg of human brain were incubated with 10 mg/ml dithiothreitol in methanol for one hour at room temperature to reduce homocysteine disulfide bonds. Lipids were removed using methyl-tert-butyl ether and the aqueous phase derivatized with N-Methyl- N-tert-butyldimethylsilyltrifluoroacetamide (MTBSTFA). Samples were subsequently analysed with a 7000 Agilent triple-quadrupole GC-MS. Multiple reaction monitoring was performed on the compounds in electron ionisation mode at 70eV. Corresponding deuterated internal standards were used to quantify compounds. Results: We identified the following transitions: 420->392, 318 424 ->396, 322; 320->292, 218, 323->295, 221; 289->189, 147 292->192, which allowed for sensitive quantification of homocysteine, methionine and methylmalonate and their deuterated standards respectively. The lowest limits of detection for homocysteine, methionine and methylmalonate were found to be 0.001 pM in three different cell lines and brain tissue. Sample preparation and analysis was complete in 4 h. Conclusion: Homocysteine, methionine and methylmalonate were successfully quantified in low cell numbers. This method is widely applicable for studies of cobalamin function in cells and has the potential advantage of conserving precious human tissue samples.