Neurosignals最新文献

Background/aims: Several factors influencing postoperative pain and the effect of opioid analgesics have been investigated on an individual level. The aim of this study was to clarify the impact of catecholamine-O-methyltransferase (COMT) gene Val158Met on opioid consumption in postoperative patients.

Methods: A systematic review and meta-analysis of the literature up to September 30, 2017, were performed by using PubMed, Cochrane Library, ISI Web of Science, and Chinese National Knowledge Infrastructure (CNKI) database. The meta-analysis examined all studies involving the association between genetic polymorphisms of COMT Val158Met and opioid consumption during the acute postoperative period.

Results: Of the 153 identified studies, 23 studies were retrieved for systematic review and 10 studies were retrieved for meta-analysis. However, it was impossible to conduct meta-analysis on the association between COMT Val158Met polymorphism and postoperative pain because of heterogeneity of the data. Overall, meta-analysis showed that COMT Val/Met carriers consumed less opioid for analgesia within the first 24 hours after surgery (SMD = 0.14, 95% CI = [0.03, 0.25], P = 0.01) but not within 48 hours (SMD = 0.14, 95% CI = [0.08, 0.36], P = 0.21). There was no significant difference in opioid consumption between Val/ Val and Met/Met patients.

Conclusion: Patients with Val/Met but not Met/Met allele variant consumed less opioid, though larger and better-designed studies are required to obtain an exclusive conclusion about the correlation between postoperative pain and COMT Val158Met polymorphism.

Background/aims: Multiple sclerosis (MS) is a prototypical autoimmune central nervous system (CNS) disease. Particularly progressive forms of MS (PMS) show significant neuroaxonal damage as consequence of demyelination and neuronal hyperexcitation. Immuno-modulatory treatment strategies are beneficial in relapsing MS (RMS), but mostly fail in PMS. Pregabalin (Lyrica®) is prescribed to MS patients to treat neuropathic pain. Mechanistically, it targets voltage-dependent Ca2+ channels and reduces harmful neuronal hyperexcitation in mouse epilepsy models. Studies suggest that GABA analogues like pregabalin exert neuroprotective effects in animal models of ischemia and trauma.

Methods: We tested the impact of pregabalin in a mouse model of MS (experimental autoimmune encephalomyelitis, EAE) and performed histological and immunological evaluations as well as intravital two-photon-microscopy of brainstem EAE lesions.

Results: Both prophylactic and therapeutic treatments ameliorated the clinical symptoms of EAE and reduced immune cell infiltration into the CNS. On neuronal level, pregabalin reduced long-term potentiation in hippocampal brain slices indicating an impact on mechanisms of learning and memory. In contrast, T cells, microglia and brain endothelial cells were unaffected by pregabalin. However, we found a direct impact of pregabalin on neurons during CNS inflammation as it reversed the pathological elevation of neuronal intracellular Ca2+ levels in EAE lesions.

Conclusion: The presented data suggest that pregabalin primarily acts on neuronal Ca2+ channel trafficking thereby reducing Ca2+-mediated cytotoxicity and neuronal damage in an animal model of MS. Future clinical trials need to assess the benefit for neuronal survival by expanding the indication for pregabalin administration to MS patients in further disease phases.

Intrinsic, rhythmic subthreshold oscillations have been described in neurons of regions throughout the brain and have been found to influence the timing of action potentials induced by synaptic inputs. Some oscillations are sodium channel-dependent while others are calcium channel-dependent. These oscillations allow neurons to fire coherently at preferred frequencies and represent the main mechanism for maintaining high frequency network activity, especially in the cortex. Because cortical circuits are incapable of maintaining high frequency activity in the gamma range for prolonged periods, those processes dependent on continuous gamma band activity are subserved by subthreshold oscillations. As such, intrinsic oscillations, coupled with synaptic circuits, are essential to prolonged maintenance of such functions as sensory perception and "binding", problem solving, memory, waking, and rapid eye movement (REM) sleep.

Background/aims: Vibrio vulnificus (V. vulnificus) is a Gram-negative marine bacterium that can cause life-threatening primary septicemia, especially in the innate immune system. But how V. vulnificus affects and acts on dendritic cells (DC) is not well understood. The aim of the present study is to investigate [Ca2+]i change and the expression of the mTor-STAT3-Bcl-2 signaling pathway in V. vulnificus B2-induced DC apoptosis, and explore the protective effect of ethylenediaminetetraacetic acid (EDTA) against DC apoptosis in a V. vulnificus B2 and DC2.4 cell coculture infection model, using EDTA as an intervenient.

Methods: The apoptosis rate, [Ca2+]i, and the expression of STAT3, m-Tor and Bcl-2 were detected by cytometry, Fluo-8-AM and Western blotting respectively.

Results: The results demonstrated that EDTA inhibited the increase of [Ca2+]i, upregulated the expression of m-Tor-STAT3-Bcl-2 signaling pathway, and protected DC against V. vulnificus B2-induced apoptosis.

Conclusions: EDTA inhibits V. Vulnificus-induced DC apoptosis by lowering [Ca2+]i via m-Tor-STAT3-Bcl-2 signaling pathway.

Beta-catenin is a protein with dual functions in the cell, playing a role in both adhesion between cells as well as gene transcription via the canonical Wnt signalling pathway. In the canonical Wnt signalling pathway, beta-catenin again plays multiple roles. In the embryonic stage, the regulation of beta-catenin levels activates genes that govern cell proliferation and differentiation. In an adult organism, beta-catenin continues to regulate the cell cycle - as a result over-expression of beta-catenin may lead to cancer. In the brain, dysfunctions in Wnt signalling related to beta-catenin levels may also cause various pathological conditions like Alzheimer's disease, Parkinson's disease, and depression. Beta-catenin can be influenced by stressful conditions and increases in glucocorticoid levels. In addition, beta-catenin can be regulated by neurotransmitters such as serotonin and dopamine. Fluctuations in beta-catenin in brain regions under duress have been associated with depressive-like behaviours. It is theorized that the change in behaviour can be attributed to the regulation of Dicer by beta-catenin. Dicer, a protein that produces micro-RNAs in the cell, is a target gene for beta-catenin. Amongst the micro-RNA that it produces are those involved in stress resilience. In this way, beta-catenin has taken its place in the well-studied biochemistry of stress and depression, and future research into this interesting protein may yet yield fruitful results in that field.

Chorea-acanthocytosis (ChAc), a neurodegenerative disease, results from loss-of-function-mutations of the chorein-encoding gene VPS13A. Affected patients suffer from a progressive movement disorder including chorea, parkinsonism, dystonia, tongue protrusion, dysarthria, dysphagia, tongue and lip biting, gait impairment, progressive distal muscle wasting, weakness, epileptic seizures, cognitive impairment, and behavioral changes. Those pathologies may be paralleled by erythrocyte acanthocytosis. Chorein supports activation of phosphoinositide-3-kinase (PI3K)-p85-subunit with subsequent up-regulation of ras-related C3 botulinum toxin substrate 1 (Rac1) activity, p21 protein-activated kinase 1 (PAK1) phosphorylation, and activation of several tyrosine kinases. Chorein sensitive PI3K signaling further leads to stimulation of the serum and glucocorticoid inducible kinase SGK1, which in turn upregulates ORAI1, a Ca2+-channel accomplishing store operated Ca2+-entry (SOCE). The signaling participates in the regulation of cytoskeletal architecture on the one side and cell survival on the other. Compromised cytoskeletal architecture has been shown in chorein deficient erythrocytes, fibroblasts and endothelial cells. Impaired degranulation was observed in chorein deficient PC12 cells and in platelets from ChAc patients. Similarly, decreased ORAI1 expression and SOCE as well as compromised cell survival were seen in fibroblasts and neurons isolated from ChAc patients. ORAI1 expression, SOCE and cell survival can be restored by lithium treatment, an effect disrupted by pharmacological inhibition of SGK1 or ORAI1. Chorein, SGK1, ORAI1 and SOCE further confer survival of tumor cells. In conclusion, much has been learned about the function of chorein and the molecular pathophysiology of chorea-acanthocytosis. Most importantly, a treatment halting or delaying the clinical course of this devastating disease may become available. A controlled clinical study is warranted, in order to explore whether the in vitro observations indeed reflect the in vivo pathology of the disease.

Background/aims: Serotonin 5HT2A and 5HT1A receptors (5HT2AR, 5HT1AR) have the closest connection to anxiety-like behavior in post-traumatic stress disorder (PTSD). However, the underlying mechanism remains unclear. In this study, we explored the connection between 5HT2A and 5HT1A receptors and anxiety-like behavior.

Methods: In the PTSD animal model, mice were exposed to conditioned fear stress coupled with single-prolonged stress (CF+SPS). Post stress infliction and behavioral tests, of which include open field, freezing behavior and elevated plus maze tests were carried out to examine establishment of the proposed model. Both Western blot analysis and immunofluorescence labeling were used to evaluate protein expressions of 5HT2AR, 5HT1AR, ERK1, ERK2 and c-Myc in the hippocampi of the mice and RT Q-PCR was employed for evaluation of the relative mRNA expressions.

Results: Based on the model established utilizing the CF+SPS procedure, we found 5HT2AR to play a positive role on anxiety-like behavior by inhibiting the expression of 5HT1AR. In addition, the ERK-c-Myc pathway elicited the effect of 5HT2AR and 5HT1AR on anxiety-like behavior in PTSD, 5-HT enhanced the anxiety-like behavior through both 5HT2AR and 5HT1AR.

Conclusion: These findings suggest competive interaction between 5HT2AR and 5HT1AR actively affects anxiety-like behavior in the hippocampi of PTSD mice via the ERK pathway.

Background: Cognitive functions progressively deteriorate during aging and neurodegenerative diseases. The present study aims at investigating differences in working memory performance as well as functional brain changes during the earliest stages of cognitive decline in health elderly individuals.

Methods: 62 elderly individuals (41 females), including 41 controls (35 females) and 21 middle cognitive impairment subjects (6 females), underwent neuropsychological assessment at baseline and an fMRI examination in a N-back paradigm contrasting 2-back vs. 0-back condition. Upon a 18 months follow-up, we identified stable controls (sCON) with preserved cognition and deteriorating controls (dCON) with -1SD decrease of performances in at least two neuropsychological tests. Data analyses included accuracy and reaction time (RT) for the 2-back condition and general linear model (GLM) for the fMRI sequence.

Results: At the behavioral level, sCON and dCON performed better than MCI in terms of accuracy and reaction time. At the brain level, functional differences in regions of the fronto-parietal network (FPN) and of the Default Mode Network (DFM) were observed. Significantly lower neural activations in the bilateral inferior and middle frontal gyri were found in MCI versus both dCON / sCON and for dCON versus sCON. Significantly increased activations in the anterior cingulate cortex and posterior cingulate cortex and bilateral insula were found in MCI versus both dCON / sCON and in dCON versus sCON.

Conclusion: The present study suggests that brain functional changes in FPN and DMN anticipate differences in cognitive performance in healthy elderly individuals with subsequent subtle cognitive decline.

Background/aims: Retinal prostheses use electrical stimulation to restore functional vision to patients blinded by retinitis pigmentosa. A key detail is the spatial pattern of ganglion cells activated by stimulation. Therefore, we characterized the spatial extent of network-mediated electrical activation of retinal ganglion cells (RGCs) in the epiretinal monopolar electrode configuration.

Methods: Healthy mouse RGC activities were recorded with a micro-electrode array (MEA). The stimuli consisted of monophasic rectangular cathodic voltage pulses and cycling full-field light flashes.

Results: Voltage tuning curves exhibited significant hysteresis, reflecting adaptation to electrical stimulation on the time scale of seconds. Responses decreased from 0 to 300 µm, and were also dependent on the strength of stimulation. Applying the Rayleigh criterion to the half-width at half-maximum of the electrical point spread function suggests a visual acuity limit of no better than 20/946. Threshold voltage showed only a modest increase across these distances.

Conclusion: The existence of significant hysteresis requires that future investigations of electrical retinal stimulation control for such long-memory adaptation. The spread of electrical activation beyond 200 µm suggests that neighbouring electrodes in epiretinal implants based on indirect stimulation of RGCs may be indiscriminable at interelectrode spacings as large as 400 µm.

The depressive state has been characterised as one of elevated inflammation, changed cardiovascular parameters and a deranged metabolic situation all of which holds promise for a better understanding and handling of treatment-resistance in affective disorders as well as for future developments in treatment algorithms. In this context several biomarkers are differentially regulated by antidepressant treatment and connected to metabolic, inflammatory, cardiovascular and apoptotic components of the pathophysiology, i.e. adiponectin, apolipoprotein-B, B-type natriuretic peptide, cortisol, CRP, cysteine, homocysteine, fibrinogen, adiponectin, BMI, glycated hemoglobin A1c, leptin, interferon-gamma, high-density lipoprotein, interleukin interleukin-1alpha, -1beta, -2, -4, -5, -6, -8, -10, -12, -13, -17, insulin-like growth factor-1, low-density lipoprotein, myeloperoxidase, osteoprotegerin, tumour necrosis factor alpha, troponins, triglycerides etc. In this context antidepressants exert different modulatory effects on the outcome, incidence and mortality concerning several severe disorders, i.e. cancer, diabetes, stroke, inflammation, stroke and cardiovascular risk. Vice versa different drugs used in the treatment of these disorders have a favourable effect in depressive states, e.g. statins, aspirine, NSAIDs, pioglitazone, celecoxib, peroxisome proliferator-activated receptor-gamma agonists and minocycline. In this review, actions of different antidepressant treatment strategies on cancer, stroke, diabetes and cardiovascular disorders are shown and the influence on the outcome of the disorders is differentially discussed. In conclusion a hypothetic model for the implication of actual findings in everyday clinical practice is proposed. In this context personalized treatment could be used to tailor treatment to specific individuals according to their clinical endophenotypes. Moreover a potential target for the development of novel intervention strategies might be used.