The tail conditions evoke different region activities relating to OKR in the hindbrain of larval Zebrafish
Authors:
Sha Sun1,2,3, Kim Ryun Drasbek1,3, Zuxiang Liu1,2
Affiliations:
Keywords:
OKR, tail-condition, cerebellum, inferior olive
Abstract:
Vertebrates have a stable retinal image during running, swimming or flying. One important mechanism to avoid the displacement of the retinal image is the optokinetic response (OKR). The other method of keeping the image stable in the vertebrate is the adjustment of the body movement. However, the interaction between OKR and body movement is unclear. To disclose this question, we record the Ca2+ signals of the active neurons in the hindbrain of GCaMP Zebrafish larvae (5 to 7 days post-fertilization) using Light-Sheet and two-photon microscopy during simultaneously recording the OKR evoked by visual stimulation under different body conditions. In fish, the body movement is generated by tail oscillation. By calculating the correlation between the Ca2+ signals and OKR, we found that cerebellum and inferior olive correlate significantly differently with OKR under tail-fixed and tail-free conditions. The cerebellum has a higher correlation for tail free condition while the pattern is reversed in the inferior olive. This suggests that the contribution of the cerebellum to smooth eye pursuit during OKR is modulated by its tail conditions, and the role of the inferior olive is also flexible. This study may provide insights into the possible mechanism by which vertebrates keep visual stability.
Authors:
Sofie Sander Høgedal, Bettina Hjelm Clausen, Lars Henrik Frich, Charlotte Madsen, Alex Christensen, Anne-Mette Homburg, Kate Lykke Lambertsen
Affiliations:
Lambertsen Lab, University of Southern Denmark (SDU)
Keywords:
Stroke, Humans, Cytokines, Receptors, Inflammation
Abstract:
Around 40,000 Danes are living with disabilities caused by stroke, many with a need for rehabilitation. The most effective treatment is thrombolysis or thrombectomy, but these present some issues of time restrictions. A possible target for treatment could be the inflammatory process, which happens in the penumbra. Studies in rodents show that anti- and proinflammatory cytokines play an important role in regulation of this process e.g. by recruiting mononuclear cells from the periphery. Up until now the connection between peripheral cytokines and stroke response has been sparsely examined in humans.
In this study we examine the role of pro- and anti-inflammatory cytokines and receptors in patients presenting with acute stroke symptoms. Blood samples were drawn from 105 patients, out of which 65 were found eligible for the study, based on predetermined set of criteria. Patients were later sorted into groups based on the diagnosis they were given.
We compare concentration of cytokines at admission and 72 hours after presentation of symptoms with samples from healthy controls. Furthermore, we correlate these values with the functional outcome of the patients measured on the mRS scale 3 months after discharge. Cytokines have the potential to become a novel drug target or prognostic marker in the treatment of stroke patients.
Authors:
M.S. Thoefner1, O.J. Bjerrum2, J.R. Nyengaard3, T.S. Jensen4, M. Berendt1
Affiliations:
Keywords:
Histology; Immunohistochemistry; Spinal cord; Spinothalamic tract; Stereology;
Abstract:
Aim: To characterise and quantify the spinal cord changes in Cavalier King Charles spaniels with symptomatic syringomyelia characterized by spontaneous or evoked scratching directed at the neck and paroxysmal pain manifestations (vocalization). To elucidate, if a correlation between structural damage at the cellular level and symptoms can be established.
Materials and methods: An explorative pilot-study on formalin fixed, paraffin imbedded spinal cord segments C1 – C8 from MRI-confirmed SM positive, symptomatic dogs (n=10) and histology-confirmed SM negative, asymptomatic dogs (n=2). Histopathological evaluation of thionine and loxul fast blue stained sections (30 μm). Stereological area and volume quantification in immunohistochemical stained (SMI-32) sections (10 μm) by means of the 2D nucleator and the Cavalieri estimator. The optical fractionator is applied for total number of neurons, glial and endothelial cell-estimation.
Preliminary results: Syringomyelia results in a loss of spinal cord grey matter. SMI-32 enables delineation of the canine spinal cord laminae I-III.
Discussion: The underlying mechanisms of central neuropathic pain in patients (dogs as well as humans) are still unknown. The ongoing characterisation of this potential spontaneous model of central neuropathic pain is a hypothesis-generating process. Future studies on glial activation and interneuronal phenotypic switch may elucidate new aspects of central sensitization in central, neuropathic pain.
Authors:
Casper Schmidt1-3, Valerie Voon3, Arne Møller1,2
Affiliations:
Keywords:
Gambling, dopamine, serotonin, impulsivity, compulsivity
Abstract:
Within the neuroscience of addiction, there is lack of evidence both in terms of assessing its mechanisms and treating its different forms. This Cambridge-Aarhus PhD project currently seeks to delineate the relationship between the roles of dopamine and serotonin in rewards, and their roles in the neuropsychological measurements of impulsivity and compulsivity. Although a lot is known about these separate roles, no research has been devoted to the basics of these neurochemical mechanisms when exposed to humans in combination.
The experiments were carried out during 2017, in a between-subjects double blinded design and contained testing of 127 subjects, including four different arms of ~25 healthy volunteers (HV) and a fifth arm of 25 subjects with gambling disorder (GD), a psychiatric patient group with profound deficits in impulsivity and compulsivity. This was done in order to isolate the neural and behavioural correlates of both increasing dopamine and depleting serotonin to investigate:
1) neural activity in a task-based fMRI experiment on different forms of rewards
2) cognitive components of impulsivity and compulsivity through behavioural testing
3) how these two points relate to a placebo GD group
4) a connectome-based DTI sequence assessing functional neural networks in HV and PG groups
We have so far found preliminary results pointing towards a successful priming of HV towards GD, indicating a potential for reversal of this priming, hopefully being able to reduce addictive symptomatology for addicted populations in the future.
Authors:
Majken B. Thomsen1, Jan Jacobsen1, Ove Noer1, Aage Kristian Olsen Alstrup1, Mette Simonsen1, David J Brooks1, Anne M. Landau1, 2
Affiliations:
Abstract:
Reduced synaptic function is observed in diseases like epilepsy, Parkinson’s and Alzheimer’s disease. [11C]UCB-J is a novel positron emission tomography (PET) tracer that binds to the synaptic vesicle 2A (SV2A) transporter, located in secretory vesicles in all areas of the brain.
We assess the potential of [11C]UCB-J as a biomarker of regional cerebral synaptic function in the living rat and pig brain, as a prelude to future studies in animal models of disease.
We performed PET studies on rats and pigs with [11C]UCB-J. We are currently comparing different kinetic models for describing tracer brain uptake kinetics and to determine its regional distribution. Furthermore, we have performed blocking experiments in rat with levetiracetam, an antiepileptic SV2A ligand, administered intravenously (iv) prior to the [11C]UCB-J PET scan.
The brain showed high and fast [11C]UCB-J uptake in both species. The blocking experiments showed reduced uptake after levetiracetam compatible with specific binding being present.
These preliminary data indicate that [11C]UCB-J PET is a good potential in vivo marker of synaptic function in the rat and pig brain. This opens the possibility to non-invasively investigate in vivo synaptic function longitudinally and in response to therapy in both small and large animal models of neurodegenerative diseases.
Authors:
Leda Abbasowa1, Anders Boysen2, Michael Kemp3, Jakob Møller-Jensen2, Bente Finsen1
Affiliations:
Keywords:
Amyloidogenesis, Infection, Curli, E.coli, APP/PS1 transgenic mice
Abstract:
Background: Epidemiological studies suggest that infections can accelerate the cognitive decline in Alzheimer´s disease (AD). In addition, genetic material from various infectious agents, including E.coli, has been detected in brain tissues of patients with AD. Also exposure to some pathogens induces Aß accumulation and tau hyperphosphorylation. The aim of this PhD study is to investigate whether systemic/CNS infections with live E.coli and curli-preparations which are bacterial amyloid surface proteins, impacts on brain pathology in the APPswe/PS1dE9 transgenic mouse model of AD and wildtype mice(WT-m).
Hypothesis/method: Since amyloidogenesis is a nucleation-dependent process, we hypothesize that curli alone or released by live E.coli serve as templates for amyloid fibril growth in AD. We expect de novo Aß accumulation in E.coli infected as well as curli-injected WT-m and exacerbation of amyloidogenesis in APPswe/PS1dE9 mice. So far, we have conducted two pilot-studies in which the effect of curli on cytokine responses in neocortex tissue samples of WT-m, has been tested. Results from these ongoing studies will be presented at OAK.
Perspectives: The possibility that the etiology of AD has a microbial contribution or that infections constitute a risk factor for the development and progression of AD would provide important avenues of novel diagnostic and therapeutic approaches in AD.
Authors:
Clement, A., Møller, A., Wiborg, O., Asuni, A.
Affiliations:
Aalborg University, Aarhus University, and Lundbeck A/S
Keywords:
Alzheimer’s disease, sleep disturbances, neuropsychiatric disturbances, Locus Coeruleus, inflammation.
Abstract:
The factors that mediate the transition from asymptomatic to full-blown Alzheimer’s disease (AD) are not well characterised, but the consensus is that the onset and tempo of disease progression is impacted significantly by neuropsychiatric disturbances (NPDs) including sleep disturbances. 97% of AD patients experience NPDs at least once during the disease, nevertheless recognising and treating NPDs remain a major challenge because the mechanisms underlying these disturbances are poorly understood. Inflammation is thought to be a strong driving factor that induces NPDs and ultimately exacerbates AD pathology. Sleep disturbances have been shown to precede AD pathology, increase the risk of developing AD, and linked to faster cognitive decline and worse prognosis.
We hypothesis that sleep disturbances via inflammation plays a prominent role in the propagation of NPDs, contribute to loss of normal brain homeostasis and accelerates cognitive decline and AD-related neuropathology. We have established a protocol for disruption of the circadian cycle to model NPDs in APPPS1-21 mice. Behavioural assays were performed to assess alterations induced by sleep disturbances followed by brain biochemistry and transcript analyses of genes regulating the circadian rhythm. Data will be presented.
Understanding the processes responsible for NPDs may hold the key to better treatment for AD.
Authors:
C. Gleesborg, H. M. Fernandes, M. L. Kringelbach, A. Møller
Affiliations:
Keywords:
Functional Parcellation Shen
Abstract:
What makes a good sub-parcellation of the brain? Classically the brain has been parcellated according to anatomical differences in cortex. More than 100 years after the pioneer Brodmann published his atlas of 43 structurally distinct regions, it is still a commonly used reference. Looking at whole-brain connectomics, one thing that is particularly important is that the parcellation used is a good fit with each participant. The main problem with the AAL parcellation is that it is based on a single individual, and given the rather large variance in human brain structure, this yields a rather high rate of error. The Shen parcellation shows promising results as a functional parcellation derived from fMRI scans. It is a very robust and homogenous parcellation compared with other modern models (Gordon et al. 2014). However, the published atlas is a fixed parcellation made with poor resolution fMRI onto a high-resolution map, and with some dilemma involving resulting tiny parcels. To improve on this method for functional parcellation we reached out to Xilin Shen, for the algorithm and guidance in overcoming certain flaws. We present here our work on a data-driven pipeline to generate a functional parcellation representative of the study-population in a given experiment.
Authors:
Tingting Gu, Kim Ryun Drasbek
Affiliations:
Keywords:
Stroke, remote ischemic conditioning, extracellular vesicles, miRNAs
Abstract:
Stroke is one of the leading causes of death and long-term disabilities resulting in large socio-economic costs. Current treatments for stroke are restricted by the limited time window and the ineffectiveness in alleviating reperfusion injuries. Remote ischemic conditioning (RIC) is a non-invasive treatment that can exert powerful protection against ischemia and reperfusion injury by simply inducing repeated cycles of controlled ischemia in the limb. However, the protective mechanisms of RIC remain unclear but is thought to involve endogenously released signals after RIC. Changes in released extracellular vesicles (EVs) are found after RIC, which are nano-sized particles that can be derived from different cells including endothelial cells, red blood cells, neurons and glia cells, mediating intercellular communication by different molecules such as lipids, proteins and miRNAs, suggesting a potential role of EVs in RIC. miRNAs are post-transcriptional regulators of protein expression. Therefore, we hypothesize that EVs mediate the protective effects of RIC by specific miRNAs. Neurological scoring, behavioural tests, and infarct size estimations will be used to measure the protective effects of RIC in a mouse stroke model. Furthermore, the protective effects of RICed EVs and RIC specific miRNAs will be tested in the mouse stroke model.
Authors:
Tanya Rhona Vigen1,2, Bente Pakkenberg1,3, Mikkel V. Olesen1
Affiliations:
Keywords:
Stereology; MSA; cell number; astrogliosis; microgliosis
Abstract:
Multiple System Atrophy (MSA) is a rapidly progressive, sporadic, neurodegenerative disorder that is clinically characterized by a combination of Parkinsonism as well as autonomic and cerebellar symptom1. The defining neuropathological hallmark of MSA is accumulation of the protein α-synuclein in oligodendrocytes. These glial cytoplasmic inclusions (GCIc) are assumed to cause dysfunction of oligodendrocytes, which eventually may lead to neuron loss2.
Previous stereological studies in MSA patients show loss of neurons and oligodendrocytes, along with an increase of astrocytes and microglial throughout the brain3,4, but no quantitative studies have examined the thalamus. Changes in the total cell number in these regions may lead to cognitive impairment, as well as motor deficits, that might explain some of the symptoms in MSA patients.
The aim of this stereological study was to quantify the total number of neurons and glial cells as well as the volume of the mediodorsal (MDT) and anterior thalamic (ANT) nuclei in brains from MSA patients (n=10) and control subjects (n=11).
Our results show significantly fewer neurons in the ANT and MDT of MSA brains compared to controls. Further, we find significantly more microglia in both regions, while the MDT displayed an increased number of astrocytes. No changes were found in the total number of oligodendrocytes between the two groups. Our results show microgliosis can occur without astrogliosis. Further, we find a reduced number of neurons in the absence of a significant degeneration of oligodendrocytes. Finally, our results suggest that cognitive impairment in MSA patients may be related to loss of neurons in the thalamus.
1Gilman et al. (2008) Neurology 71:670-676
2Zang et al. (2018) Aging and disease 9:1:102:108
3Salvesen et al. (2017) Cerebral cortex 27:400:410
4Salvesen et al. (2015) Neurobiology of disease 74:104:113
Authors:
Ellman D. G.1, Lund M. C.1, Novrup H. G.1, Nedospasov S. A.2, Lambertsen K. L.1,3,4
Affiliations:
Keywords:
Spinal cord injury, TNF.
Abstract:
Spinal cord injury (SCI) is a devastating condition causing paralysis from the level of the injury and below. Currently there are no treatment for SCI. In our studies we are using transgenic mice and pharmacological treatment to investigate the mechanisms underlying the secondary injury after SCI, with special focus on tumor necrosis factor (TNF). We have previously shown that direct administration of XPro1595, a dominant negative inhibitor of soluble TNF (solTNF), results in reduced lesion size and improved functional recovery, while direct or systemic administration of Etanercept, an inhibitor of TNF, and systemic administration of XPro1595 did not. In addition we have shown that genetic ablation of solTNF does not affect lesion size and functional recovery after SCI.
We have also shown (unpublished) that conditional ablation of myeloid TNF reduce lesion size and improves functional recovery after SCI. Based on our previously results we want to investigate the effect of direct administration of XPro1595 to mice with conditional ablation of myeloid TNF on lesion size and functional recovery, since we have shown that both, on their own, are beneficial after SCI.
Since TNF and its receptors are accessible drug targets, there is real prospect that this work lead to new potential neuroprotective targets in SCI therapy.
Authors:
Rasmus Rydbirk1, Tomasz Brudek1, Bente Pakkenberg1,2, Jorg Tost3, Susana Aznar1
Affiliations:
Keywords:
Multiple System Atrophy; Epigenome-Wide Association Study, Prefrontal Cortex, Immune system
Abstract:
Multiple System Atrophy (MSA) is a neurodegenerative disease with a short survival time. Due to its low incidence, knowledge regarding aetiology and progression of MSA is limited. In the present study, we screened for epigenetic changes in the dorsomedial prefrontal cortex (dmPFC) in order to identify genes that may be transcriptionally altered through epigenetic modifications.
We obtained dmPFCs of 40 MSA patients and 37 controls from brain banks at Bispebjerg Hospital (DK) and Kings College London (UK). We treated the DNA with a commercial kit (CEGX), and used Infinium MethylationEPIC kits (Illumina) on an Illumina IScan instrument to quantify cytosine methylation. Bioinformatic analyses were performed in R using the ChAMP pipeline.
We used the 2,000 most differently methylated positions for Gene Onthology (GO) analyses that indicated relations to antigen presentation and other immune pathways. Leading Edge Analyses identified overrepresented genes in the top ten Gos including HLA-A, -E and –F. Finally, using RT-qPCR we identified an overall increase in MHC class I expression in MSA patients compared with controls.
In line with our previously results we find indications of an activated immune system in MSA. Future studies will determine the exact role of these mechanisms in relation to disease processes.
Authors:
H. Gredal, E. Andersen-Ranberg, M. Berendt
Affiliations:
Dept. of Veterinary Clinical Sciences, University of Copenhagen
Keywords:
Autoimmune encephalitis, inflammation, biomarker, NMDA receptor
Abstract:
Although rare, autoimmune encephalitides are diagnosed with increasing frequency in humans. Autoantibodies against NMDA receptors have been identified as part of the pathogenesis, yet knowledge of specific disease mechanisms and diagnostics is still limited.
In dogs, encephalitides and meningitides with an autoimmune aetiology are common, in fact far more common than infectious central nervous system (CNS) diseases. Dogs present with neurological signs often resembling those in humans including seizures, mental disturbances, and specific neurological deficits (paralyses, ataxia etc.) reflecting the affected structures.
We intend to conduct a comparative study of autoimmune encephalitis and meningitis in dogs with the following objectives:
To investigate and compare
1. the clinical disease of autoimmune encephalitis
2. diagnostic imaging findings
3. possible underlying autoimmune mechanisms (including NMDA receptor antibodies)
4. novel biomarkers of autoimmune inflammatory CNS disease in dogs for diagnostic purposes
Dogs with autoimmune inflammatory CNS disease are included at the University Hospital for Companion Animals, University of Copenhagen. Routine diagnostic work-up with standard blood work, MRI and CSF analysis is performed in all dogs. Serum and CSF are stored for future investigations.
A pilot study of NMDA receptor antibodies in dogs did not reveal any significant results. However, laboratory methods need further optimization.
Authors:
Pall Karlsson1,2, Maria Nolano3, Sanda Gylfadottir1, Mohopatra Durga4, Andrew Shepherd4, Andreas Themistocleous5, David Bennett5, Michael Polydefkis6, Nanna Finnerup1, Jens Randel Nyengaard2, Troels Staehelin Jensen1
Affiliations:
Keywords:
Diabetes, diabetic polyneuropathy, skin biopsy, nerve fibre, pain
Abstract:
Diabetic polyneuropathy (DPN) develops in up to 50% of diabetic patients, and is present either as pain-free or painful DPN. A pathological hallmark of DPN is a decrease in unmyelinated intraepidermal nerve fibres, as assessed by a 3-mm skin biopsy. The skin biopsy is an excellent diagnostic tool, with diagnostic power of around 85%. The quantification of the nerve fibres does not, however, explain the different symptoms reported by the patients. Patients with and without painful symptoms have the same low nerve fibre density. Current pain treatment is insufficient and will remain so, until we have a better understanding of the pathophysiology behind neuropathic pain and the mechanisms that cause the different symptom profiles. An important step towards improved mechanism-based treatment is to extract more information from the skin biopsies.
Our findings that indicate that diabetic patients without neuropathy have increased axonal swellings on the fibres compared with healthy controls and DPN patients, and may be a prelude to neuropathy and are the first sign of diseased fibres. On the other hand, patients with painful DPN have increased occurrence of macrophages in the epidermis and dermis in patients with painful DPN compared with healthy individuals and pain-free neuropathic patients.
Authors:
Reza Khorooshi1, Emil Ulrikkaholm Tofte-Hansen1, Camilla Thygesen 1, Roser Montanana Rosell1, Hannah Liska Limberg1, Nasrin Asgari1, Ulrike Muscha Steckelings2 and Trevor Owens1
Affiliations:
Keywords:
Neuromyelitis optica spectrum disorder; Angiotensin II type 2 Receptor; Astrocyte pathology; IL-10; Compound 21
Abstract:
Neuromyelitis optica spectrum disorder (NMOSD) is a primary astrocyte disease of the CNS. An IgG autoantibody specific for the astrocyte water channel aquaporin-4 (AQP4) is thought to initiate astrocyte pathology. Current treatment is non-curative. Angiotensin II type 2 Receptor (AT2R) is proposed to have neuroprotective effects, which may involve the induction of IL-10. We hypothesized that AT2R stimulation in the CNS induces IL-10 and plays a protective role in NMOSD-like pathology. To test this, NMOSD-like pathology was induced in mice by intracerebral co-injection of NMOSD-IgG and human complement. Mice were treated with the AT2R agonist compound 21 (C21). NMOSD-like pathology was evaluated by quantification of AQP4- and GFAP-loss. NMOSD-like pathology was significantly attenuated by treatment with C21. Administration of C21 led to induction of IL-10, suggesting the involvement of IL-10 in the therapeutic effect of C21. IL-10 deficient mice showed exacerbated NMOSD-like pathology, indicating a potential protective role of IL-10. Treatment with C21 reduced pathology in some but not all IL-10 deficient mice, indicating that the protective effect of AT2R stimulation was not absolutely dependent on IL-10. Our findings identify AT2R as a new potential target in NMOSD therapy and IL-10 as an important cytokine that regulates pathology in NMOSD.
Authors:
Eugenio Gutiérrez-Jiménez, Signe K. Fruekilde, Peter M. Rasmussen, Irene K. Mikkelsen, Luca Bordoni, Nina K. Iversen, Leif Østergaard
Affiliations:
CFIN, Department of Clinical Medicine, Aarhus University.
Keyword:
Brain hemodynamics, Oxygen, Cerebral Blood Flow
Abstracts:
Changes in brain hemodynamics accompany neuronal activation. Most of these effects have been examined in anesthetized rodents; however, anesthesia affects the regulation of cerebral circulation throughout the brain. In this project, we evaluated the steady-state hemodynamics in the mouse brain barrel cortex during the awake state. We measured intravascular oxygen partial pressure (PO2) and mean transit-time using two-photon microscopy. We also analyzed the relative changes in CBF (Laser Doppler Flowmetry) and intravascular oxygen tension during functional activation with whiskers stimulation (10s). All imaging methodologies were performed in awake, head-restrained C57BL/6 mice (n=6), through a chronic sealed cranial window centered over the C2 whisker barrel. During steady state, MTT was 0.46 ± 0.14 s, arterial PO2 was 93.8 ± 17.9 mmHg, and venous PO2 was 41.1 ± 3.6 mmHg. The estimated oxygen extraction fraction was of 0.55 ± 0.07. During functional activation, CBF significantly increased by 6.8 ± 4.0%. Changes in PO2 increased in both arterial and venous network by 2.0 ± 10.4% and 7.4 ± 8.9 %. Our data shows novel optical imaging techniques for brain hemodynamics in awake mice. The estimations presented in this work can be applied in disease models to evaluate the effect of the pathology in the brain oxygen diffusion and hemodynamics.
