Articles: chronic.
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Persistent or chronic pain is the primary reason people seek medical care, yet current therapies are either limited in efficacy or cause intolerable side effects. Diverse mechanisms contribute to the basic phenomena of nociceptor hyperexcitability that initiates and maintains pain. Two prominent players in the modulation of nociceptor hyperexcitability are the transient receptor potential vanilloid type 1 (TRPV1) ligand-gated ion channel and the voltage-gated potassium channel, Kv7.2/3, that reciprocally regulate neuronal excitability. ⋯ Importantly, this specific MOA is not associated with any previously described Kv7.2/3 or TRPV1 class-specific side effects. We suggest that the therapeutic potential of this MOA is derived from the selective and specific targeting of a subpopulation of nociceptors found in rodents and humans. This efficacy and safety profile supports the advancement of dual TRPV1-Kv7.2/3 modulating compounds into preclinical and clinical development for the treatment of chronic pain.
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Central sensitization (CS) is believed to play a role in many chronic pain conditions. Direct non-invasive recording from single nociceptive neurons is not feasible in humans, complicating CS establishment. This review discusses how secondary hyperalgesia (SHA), considered a manifestation of CS, affects physiological measures in healthy individuals and if these measures could indicate CS. It addresses controversies about heat sensitivity changes, the role of tactile afferents in mechanical hypersensitivity and detecting SHA through electrical stimuli. Additionally, it reviews the potential of neurophysiological measures to indicate CS presence. ⋯ Gathering evidence for CS in humans is a crucial research focus, especially with the increasing interest in concepts such as 'central sensitization-like pain' or 'nociplastic pain'. This review clarifies which readouts, among the different behavioural and neurophysiological proxies tested in experimental settings, can be used to infer the presence of CS in humans.
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Non-malignant chronic pain is a clinical challenge because pharmacological treatment often fails to relieve pain. Transcranial direct current stimulation (tDCS) is a treatment that could have the potential for pain relief and improvement in quality of life. However, there is a lack of clinical trials evaluating the effects of tDCS on the pain system. The aim of the present study was to evaluate the effect of 5 days of anodal tDCS treatment on the pain system in chronic non-malignant pain patients using quantitative sensory testing (QST) and quality of life questionnaires: (1) Brief Pain Inventory-short form (BPI-sf), (2) European Organization for Research and Treatment of Life Questionnaire (EORTC-C30), and (3) Hospital Anxiety Depression Scale (HADS). ⋯ This study adds to the evidence in the literature that tDCS may be a potential therapeutic tool for the management of non-malignant chronic pain.
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Motivation can be investigated with the BIS (Behavioural Inhibition System)/BAS (Behavioural Activation System) scale. BAS regulates the motivation to approach goal-oriented outcomes, particularly rewarding stimuli and situations, while BIS regulates escape and avoidance of unpleasant outcomes. Chronic whiplash-associated disorders (WAD) is a heterogenous pain condition with known alterations in motivated behaviour. The study aimed (1) to investigate the relationship between BIS/BAS, and pain and disability with quality of life and psychological measures in chronic WAD; (2) to determine if BIS and/or BAS mediate the relationships between pain, disability, and psychological symptoms and quality of life. ⋯ In line with current theories, we found a large proportion (30%-50%) of patients with whiplash-associated disorders (WAD) showing signs of altered function in the Behavioural Inhibition System (BIS) and Behavioural Activation System (BAS) suggesting altered reward processing and motivation in these patients. While such altered functions showed associations with pain interference, disability and all mental health measures, reward processing could no be demonstrated as a pathogenetically relevant factor in chronic WAD patients.
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Chronic pain, affecting approximately 20% of the global population, is the leading cause of disability worldwide. Transgender individuals are disproportionately exposed to chronic pain risk factors compared with the cisgender population. This study compares the incidence of chronic pain between transgender and cisgender individuals and examines the impact of gender affirming hormone therapy, anxiety, and depression on chronic pain. ⋯ Our study, featuring the largest cohort of Transgender and Gender Diverse (TGD) individuals assembled to date, reveals critical disparities in chronic pain among TGD populations, notably those on hormone therapy, compared with the cisgender population. It highlights the urgent need for specialized screening and treatment for this vulnerable population, and research into hormone therapy's impact on pain. These insights aim to foster more effective, personalized healthcare, enhancing the well-being and quality of life for the TGD community.