19 research outputs found

    The systemic response to topical Aldara treatment is mediated through direct TLR7 stimulation as Imiquimod enters the circulation

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    Topical application of Aldara cream, containing the Toll-like receptor 7/8 agonist Imiquimod, is a widely used mouse model for investigating the pathogenesis of psoriasis. We have previously used this model to study the effects of peripheral inflammation on the brain, and reported a brain-specific response characterised by increased transcription, infiltration of immune cells and anhedonic-like behavior. Here, we perform a more robust characterisation of the systemic response to Aldara application and find a potent but transient response in the periphery, followed by a prolonged response in the brain. Mass spectrometry analysis of plasma and brain samples identified significant levels of Imiquimod in both compartments at molar concentrations likely to evoke a biological response. Indeed, the association of Imiquimod with the brain correlated with increased Iba1 and GFAP staining, indicative of microglia and astrocyte reactivity. These results highlight the potency of this model and raise the question of how useful it is for interpreting the systemic response in psoriasis-like skin inflammation. In addition, the potential impact on the brain should be considered with regards to human use and may explain why fatigue, headaches and nervousness have been reported as side effects following prolonged Aldara use

    Neuro-immune responses to distal immune stimulus

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    Depression is a major disease burden worldwide and, despite its prevalence and socioeconomic costs, around 30% of patients do not respond to currently available treatments. Inflammation is increasingly associated with, not only depressive illness but also resistance to existing therapies. This highlights the need for investigation of the mechanisms of neuro-inflammation, particularly in the context of peripheral inflammatory stimuli. Specifically, the chemokine molecular family is increasingly associated with human depressive illness, and neuro-inflammation and behavioural change in rodent models, making this an attractive molecular family for study. This thesis describes research aimed at investigating the association of these molecules with human depression and analysis of their role in an animal model of peripherally stimulated neuro-inflammation, the Aldara model of psoriasis-like inflammation. Systematic review and meta-analysis of the human biomarker literature using a random effects, inverse variance model revealed that a number of chemokines (CCL2, CCL3, CCL4, CCL11, CXCL4, CXCL7, CXCL8) are significantly associated with depressive illness in a human population. However this work revealed that there are a number of limitations of the human literature primarily associated with the methodological challenges of studies in human populations and confounding factors. Alongside this work, the Aldara model, which utilises the toll-like receptor 7 (TLR7) ligand imiquimod (IMQ), was investigated as a tool for studying neuroinflammation. Initial time-course investigation revealed that significant chemokine and cytokine transcriptional alterations occur within four hours at the local site of cutaneous treatment, the peripheral tissues and the brain. In addition, protein quantification in the brain confirmed that many of these transcriptional responses are translated to protein. Interestingly, it was shown that the brain response was temporally distinct from that of the peripheral tissues, and that in general brain responses were induced slightly more slowly and persisted for a longer period of time than those in the periphery. Investigation of Iba1+ (microglia/monocytes), GFAP+ (astrocytes) and CD3+ (T-cells) cells within the brain revealed significant changes in the microglial and T-cell populations, which were consistent with microgliosis and T-cell recruitment to the brain parenchyma. Changes in astrocyte populations were more equivocal although there was evidence of astrogliosis. Mechanistic investigations into responses to the Aldara model in inflammatory chemokine receptor (iCCR) KO mice did not reveal significant alterations in chemokine and cytokine transcription or in microglial responses to cutaneous Aldara treatment in the absence of the iCCRs (CCR1, CCR2, CCR3 and CCR5), but there did appear to be evidence of reduced CD3+ T-cell recruitment. In contrast, investigations in type I interferon receptor (IFNAR) KO mice identified a clear role for type I IFN signalling through IFNAR in the induction of chemokine and cytokine gene expression in the brain, and associated changes in Iba1+ microglial and CD3+ T-cell populations in response to cutaneous Aldara treatment. Mass spectrometric analysis of IMQ, the main active ingredient of Aldara, revealed that within four hours it enters both the circulation and the brain. The finding of IMQ within the brain parenchyma suggests that, while it is not an appropriate tool for studying peripheral-central immune crosstalk, it is a useful non-invasive model of TLR7 mediated neuroinflammation. These data provide compelling evidence of a role for chemokines in human depression and in neuro-inflammation, although the precise actions of this family of molecules remain unclear. In addition, building on previous work, the Aldara model appears to be a suitable tool for the study of neuro-inflammation, particularly interferon-driven immune responses, but is less appropriate for studying peripherally driven CNS immune reactions. Further work into the specific role of chemokines and associated cellular populations will hopefully provide additional insight into how CNS immune reactions are co-ordinated

    Engagement with emotional concerns in general practice: thematic analysis of GP consultations

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    BACKGROUND: Emotional concerns (defined as any expression of low mood, anxiety or psychosocial stress) are an important part of the biopsychosocial care model used in modern medical practice. Previous work has demonstrated variable engagement with emotional concerns and that improved communication has been associated with reductions in emotional distress. AIM: To examine how emotional concerns are engaged with during routine GP consultations. DESIGN AND SETTING: Secondary study using the HARI database. The available dataset contains 231 recordings from 10 GPs across 8 urban and suburban practices recorded in 2017 and 2018. METHOD: The dataset was reviewed to identify any consultations containing emotional concerns (as defined as any expression of low mood, anxiety or psychosocial stress) before being imported into NVivo 12 to facilitate thematic analysis and coding. Reflexive inductive thematic analysis resulted in two major themes. RESULTS: Engagement with emotional concerns is dynamic throughout consultations (Theme 1). This dynamism relates to competing areas of focus, immediate versus delayed engagement and re-iteration of concerns throughout consultations. Emotional concerns can be engaged with in a similar way to physical concerns (Theme 2) using a diagnostic and treatment-based approach, however in addition to this therapeutic listening and conversation is utilised. CONCLUSION: Awareness of the dynamic nature of emotional concerns within consultations and encouraging engagement with concerns in a flexible and patient-oriented manner may help improve doctor-patient communication. In addition, investigating how GPs and patients build shared understanding around emotional concerns may identify methods to reduce patients' emotional distress

    Printable microscale interfaces for long-term peripheral nerve mapping and precision control

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    The nascent field of bioelectronic medicine seeks to decode and modulate peripheral nervous system signals to obtain therapeutic control of targeted end organs and effectors. Current approaches rely heavily on electrode-based devices, but size scalability, material and microfabrication challenges, limited surgical accessibility, and the biomechanically dynamic implantation environment are significant impediments to developing and deploying advanced peripheral interfacing technologies. Here, we present a microscale implantable device – the nanoclip – for chronic interfacing with fine peripheral nerves in small animal models that begins to meet these constraints. We demonstrate the capability to make stable, high-resolution recordings of behaviorally-linked nerve activity over multi-week timescales. In addition, we show that multi-channel, current-steering-based stimulation can achieve a high degree of functionally-relevant modulatory specificity within the small scale of the device. These results highlight the potential of new microscale design and fabrication techniques for the realization of viable implantable devices for long-term peripheral interfacing.https://www.biorxiv.org/node/801468.fullFirst author draf

    TLR7-mediated skin inflammation remotely triggers chemokine expression and leukocyte accumulation in the brain

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    Background: The relationship between the brain and the immune system has become increasingly topical as, although it is immune-specialised, the CNS is not free from the influences of the immune system. Recent data indicate that peripheral immune stimulation can significantly affect the CNS. But the mechanisms underpinning this relationship remain unclear. The standard approach to understanding this relationship has relied on systemic immune activation using bacterial components, finding that immune mediators, such as cytokines, can have a significant effect on brain function and behaviour. More rarely have studies used disease models that are representative of human disorders. Methods: Here we use a well-characterised animal model of psoriasis-like skin inflammation—imiquimod—to investigate the effects of tissue-specific peripheral inflammation on the brain. We used full genome array, flow cytometry analysis of immune cell infiltration, doublecortin staining for neural precursor cells and a behavioural read-out exploiting natural burrowing behaviour. Results: We found that a number of genes are upregulated in the brain following treatment, amongst which is a subset of inflammatory chemokines (CCL3, CCL5, CCL9, CXCL10, CXCL13, CXCL16 and CCR5). Strikingly, this model induced the infiltration of a number of immune cell subsets into the brain parenchyma, including T cells, NK cells and myeloid cells, along with a reduction in neurogenesis and a suppression of burrowing activity. Conclusions: These findings demonstrate that cutaneous, peripheral immune stimulation is associated with significant leukocyte infiltration into the brain and suggest that chemokines may be amongst the key mediators driving this response

    Rheumatoid arthritis and depression: an inflammatory perspective

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    The coexistence of immune-mediated inflammatory diseases with depression has long been recognised. Data that illustrate the intimate associations between peripheral and brain immune responses raise the possibility of shared pathophysiological mechanisms. These associations include the negative effects of proinflammatory cytokines on monoaminergic neurotransmission, neurotrophic factors, and measures of synaptic plasticity. The evidence supporting this association is accumulating and includes findings from clinical trials of immunomodulatory therapy, indicating that these interventions can provide benefits to mental health independent of improvements in physical disease scores. In this Review, we assess this evidence in relation to rheumatoid arthritis and depression, with a focus on innate immune and molecular responses to inflammation, and discuss the challenges of assessing causation in this population, acknowledging the difficulty of assessing the confounding and contributory effects of pain and fatigue. We also discuss how future clinical and preclinical research might improve diagnosis of depression in people with rheumatoid arthritis and shed light on mechanisms that could be substrates for therapeutic interventions

    Information as an economic good. Value of information and its role in the financial market

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    Diplomová práce popisuje roli a hodnotu informací na finančních a kapitálových trzích. Vychází z toho, že z informacemi a nabytými znalostmi by mělo být zacházeno jako s aktivy. Práce popisuje, jak je s těmito aktivy nakládáno, jakým procesem procházejí a jaké subjekty na na trhu s investičními informacemi vystupují. Z teoretického hlediska jsou v práci popisovány vztahy mezi informační ekonomikou a finančními trhy. Práce je zaměřena jednak na internetové prostředí a jednak je popisována z pohledu individuálního investora. Úvaha, zda v této oblasti informační ekonomiky nalezne své místo informační pracovník, celou práci uzavírá
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