Review Article
Systematic review of gene expression studies in people with Lewy body dementia
- Anisa Chowdhury, Anto P. Rajkumar
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- Published online by Cambridge University Press:
- 17 March 2020, pp. 281-292
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Objectives:
Lewy body dementia (LBD) is the second most prevalent neurodegenerative dementia and it causes more morbidity and mortality than Alzheimer’s disease. Several genetic associations of LBD have been reported and their functional implications remain uncertain. Hence, we aimed to do a systematic review of all gene expression studies that investigated people with LBD for improving our understanding of LBD molecular pathology and for facilitating discovery of novel biomarkers and therapeutic targets for LBD.
Methods:We systematically reviewed five online databases (PROSPERO protocol: CRD42017080647) and assessed the functional implications of all reported differentially expressed genes (DEGs) using Ingenuity Pathway Analyses.
Results:We screened 3,809 articles and identified 31 eligible studies. In that, 1,242 statistically significant (p < 0.05) DEGs including 70 microRNAs have been reported in people with LBD. Expression levels of alternatively spliced transcripts of SNCA, SNCB, PRKN, APP, RELA, and ATXN2 significantly differ in LBD. Several mitochondrial genes and genes involved in ubiquitin proteasome system and autophagy–lysosomal pathway were significantly downregulated in LBD. Evidence supporting chronic neuroinflammation in LBD was inconsistent. Our functional analyses highlighted the importance of ribonucleic acid (RNA)-mediated gene silencing, neuregulin signalling, and neurotrophic factors in the molecular pathology of LBD.
Conclusions:α-synuclein aggregation, mitochondrial dysfunction, defects in molecular networks clearing misfolded proteins, and RNA-mediated gene silencing contribute to neurodegeneration in LBD. Larger longitudinal transcriptomic studies investigating biological fluids of people living with LBD are needed for molecular subtyping and staging of LBD. Diagnostic biomarker potential and therapeutic promise of identified DEGs warrant further research.
Original Article
Exploring test batteries for depression- and anxiety-like behaviours in female and male ICR and black Swiss mice
- Lydmila Kazavchinsky, Sofi Dahan, Haim Einat
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- Published online by Cambridge University Press:
- 07 May 2020, pp. 293-302
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Objective and rationale: Animal models are critical for the study of mental disorders and their treatments but are repeatedly criticized for problems with validity and reproducibility. One approach to enhance validity and reproducibility of models is to use test batteries rather than single tests. Yet, a question regarding batteries is whether one can expect a consistent individual behavioural phenotype in mice across tests that can be presumed to be part of the same construct. This study was designed to explore the relationship between the behaviours of mice across tests in some variations of test batteries for depression- and anxiety-like behaviours. Methods: Female and male healthy, intact, and untreated mice from the ICR and black Swiss strains were used in four separate experiments. With some variations, mice were exposed to a battery of behavioural tests representing affective- and anxiety-like behaviours. Data were analysed for differences between sexes and for correlations between behaviours within and across the tests in the battery. Results: No differences were found between the sexes. With very few exceptions, we found correlations within tests (when one test has more than one measure or is repeated) but not across different tests within the battery. Conclusions: The results cast some doubt on the utility of behavioural test batteries to represent different facets of emotional behaviour in healthy intact outbred mice, without any interventions or treatments. Additional studies are designed to explore whether stronger relationship between the tests will appear after manipulations or drug treatments.
Effect of the monoaminergic stabiliser (−)-OSU6162 on mental fatigue following stroke or traumatic brain injury
- Marie K.L. Nilsson, Birgitta Johansson, Maria L. Carlsson, Robert C. Schuit, Lars Rönnbäck
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- Published online by Cambridge University Press:
- 18 May 2020, pp. 303-312
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Objective:
The purpose of the present study was to evaluate the efficacy and safety of (−)-OSU6162 in doses up to 30 mg b.i.d. in patients suffering from mental fatigue following stroke or traumatic brain injury (TBI).
Methods:This 4 + 4 weeks double-blind randomised cross-over study included 30 patients afflicted with mental fatigue following a stroke or head trauma occurring at least 12 months earlier. Efficacy was assessed using the Mental Fatigue Scale (MFS), the Self-rating Scale for Affective Syndromes [Comprehensive Psychopathological Rating Scale (CPRS)], the Frenchay Activity Index (FAI), and a battery of neuropsychological tests. Safety was evaluated by recording spontaneously reported adverse events (AEs).
Results:There were significant differences on the patients’ total FAI scores (p = 0.0097), the subscale FAI outdoor scores (p = 0.0243), and on the trail making test (TMT-B) (p = 0.0325) in favour of (−)-OSU6162 treatment. Principal component analysis showed a clear overall positive treatment effect in 10 of 28 patients; those who responded best to treatment had their greatest improvements on the MFS. Reported AEs were mild or moderate in severity and did not differ between the (−)-OSU6162 and the placebo period.
Conclusion:The most obvious beneficial effects of (−)-OSU6162 were on the patients’ activity level, illustrated by the improvement on the FAI scale. Moreover, a subgroup of patients showed substantial improvements on the MFS. Based on these observed therapeutic effects, in conjunction with the good tolerability of (−)-OSU6162, this compound may offer promise for treating at least part of the symptomatology in patients suffering from stroke- or TBI-induced mental fatigue.
Interleukin-6 and total antioxidant capacity levels following N-acetylcysteine and a combination nutraceutical intervention in a randomised controlled trial for bipolar disorder
- C.C. Bortolasci, C. Voigt, A. Turner, M. Mohebbi, L. Gray, S. Dodd, K. Walder, M. Berk, S.M. Cotton, G.S. Malhi, C.H. Ng, N. Dowling, J. Sarris, O.M. Dean
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- Published online by Cambridge University Press:
- 30 June 2020, pp. 313-320
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Objective:
The aims of this study were to evaluate changes in inflammatory and oxidative stress levels following treatment with N-acetylcysteine (NAC) or mitochondrial-enhancing agents (CT), and to assess the how these changes may predict and/or moderate clinical outcomes primarily the Montgomery-Åsberg Depression Rating Scale (MADRS).
Methods:This study involved secondary analysis of a placebo-controlled randomised trial (n = 163). Serum samples were collected at baseline and week 16 of the clinical trial to determine changes in Interleukin-6 (IL-6) and total antioxidant capacity (TAC) following adjunctive CT and/or NAC treatment, and to explore the predictability of the outcome or moderator effects of these markers.
Results:In the NAC-treated group, no difference was observed in serum IL-6 and TAC levels after 16 weeks of treatment with NAC or CT. However, results from a moderator analysis showed that in the CT group, lower IL-6 levels at baseline was a significant moderator of MADRS χ2 (df) = 4.90, p = 0.027) and Clinical Global Impression-Improvement (CGI-I, χ2 (df) = 6.28 p = 0.012). In addition, IL-6 was a non-specific but significant predictor of functioning (based on the Social and Occupational Functioning Assessment Scale (SOFAS)), indicating that individuals with higher IL-6 levels at baseline had a greater improvement on SOFAS regardless of their treatment (p = 0.023).
Conclusion:Participants with lower IL-6 levels at baseline had a better response to the adjunctive treatment with the mitochondrial-enhancing agents in terms of improvements in MADRS and CGI-I outcomes.
Involvement of NLRP3 inflammasome in schizophrenia-like behaviour in young animals after maternal immune activation
- Letícia Ventura, Viviane Freiberger, Vinicius B. Thiesen, Paula Dias, Matheus L. Dutra, Bruna B. Silva, Aline D. Schlindwein, Clarissa M. Comim
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- Published online by Cambridge University Press:
- 14 July 2020, pp. 321-327
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Objective:
To evaluate the involvement of nod-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome in schizophrenia-like behaviour in young animals exposed to maternal immune activation (MIA).
Methods:To this aim, on the 15th gestational day, the females received an injection of lipopolysaccharides. When the animals completed 7, 14 and 45 postnatal days, they were killed and the whole brain was dissected for biochemical analysis. Animals with 45 postnatal days were submitted to behavioural tests of locomotor activity, social interaction and stereotyped movements.
Results:It was observed that the animals presented schizophrenia-like behaviour at 45 postnatal days associated with the increase of NLRP3 inflammasome expression and IL-1β levels on 7, 14 and 45 postnatal days.
Conclusion:This study shows that MIA may be associated with a schizophrenia-like behaviour. This behaviour can be induced to a neuroinflammatory profile in the brain. These evidences may base future studies on the relationship between neuroinflammation and psychiatric disorders.
Low-frequency rTMS inhibits the anti-depressive effect of ECT. A pilot study
- Poul Erik Buchholtz, Mahmoud Ashkanian, Simon Hjerrild, Line Kirstine Hauptmann, Torben Albert Devantier, Paulina Jensen, Sanne Wissing, Mette Viller Thorgaard, Laerke Bjerager, Julie Lund, Anja Johnsen Alrø, Maria Simonsen Speed, Rene Børge Korsgaard Brund, Poul Videbech
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- Published online by Cambridge University Press:
- 27 July 2020, pp. 328-338
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Objective:
Low-frequency repetitive transcranial magnetic stimulation (rTMS) of the prefrontal cortex has been shown to have a statistically and clinically significant anti-depressant effect. The present pilot study was carried out to investigate if right prefrontal low-frequency rTMS as an add-on to electroconvulsive therapy (ECT) accelerates the anti-depressant effect and reduces cognitive side effects.
Methods:In this randomised, controlled, double-blind study, thirty-five patients with major depression were allocated to ECT+placebo or ECT+low-frequency right prefrontal rTMS. The severity of depression was evaluated during the course using the Hamilton scale for depression (the 17-item as well as the 6-item scale) and the major depression inventory (MDI). Furthermore, neuropsychological assessment of cognitive function was carried out.
Results:The study revealed no significant difference between the two groups for any of the outcomes, but with a visible trend to lower scores for MDI after treatment in the placebo group. The negative impact of ECT on neurocognitive functions was short-lived, and scores on logical memory were significantly improved compared to baseline 4 weeks after last treatment. The ECT-rTMS group revealed generally less impairment of cognitive functions than the ECT-placebo group.
Conclusion:The addition of low-frequency rTMS as an add-on to ECT treatment did not result in an accelerated response. On the contrary, the results suggest that low-frequency rTMS could inhibit the anti-depressant effect of ECT.