European journal of pain : EJP
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Randomized Controlled Trial
Exercise-induced hypoalgesia in young adult females with long-standing patellofemoral pain - A randomized crossover study.
Patellofemoral pain (PFP) is a common knee pain condition where hip and knee exercises help improve treatment outcomes. This study compared the acute effect of hip versus knee exercises on anti-nociceptive and pro-nociceptive mechanisms in young females with long-standing PFP. ⋯ A general hypoalgesic response to slowly increasing pressure stimuli was observed following both hip and knee exercises as well as decreased conditioned pain modulation, potentially indicating an attenuated ability from exercise to inhibit pain.
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Randomized Controlled Trial
The effect of intradermal microdosing of a transient receptor potential cation channel subfamily V member 1 antagonist on heat evoked pain and thermal thresholds in normal and ultraviolet-C exposed skin in healthy volunteers.
Three TRPV1 (Transient Receptor Potential Vanilloid Receptor 1) antagonists were developed for testing in situ in human skin (Sjögren et al., 2016; Sjögren et al., 2018; Sjögren et al., 2018). The first human study using these compounds and capsaicin, was performed to determine the required local antagonist concentrations needed for target engagement (Proof of Mechanism, PoM) (Sjögren et al., 2018). In this paper, the aim was to address a TRPV1 antagonist's ability to inhibit a more complex pain signal and to define translational endpoints that could be used in further drug development, when progressing orally bioavailable TRPV1 antagonists as novel analgesic medications. ⋯ This study validated translational tools to confirm target engagement for TRPV1 antagonists; WDT, HPT and STHP have utility in this respect, after oral administration of a TRPV1 antagonist. This study also proved that TRPV1 antagonists can inhibit a more complex, non-capsaicin dependent thermally induced pain signal.
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Randomized Controlled Trial
Eye-movement behaviours when viewing real-world pain-related images.
Pain-related cues are evolutionarily primed to capture attention, although evidence of attentional biases towards pain-related information is mixed in healthy individuals. The present study explores whether healthy individuals show significantly different eye-movement behaviours when viewing real-world pain-related scenes compared to neutral scenes. The effect of manipulating via written information the threat value of the pain-related scenes on eye-movement behaviours was also assessed. ⋯ Healthy individuals show different eye-movement behaviours when viewing pain-related scenes than neutral scenes, supporting evolutionary accounts of pain. Implications for the onset and/or maintenance of chronic pain need to be explored.
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Pain models are commonly used in drug development to demonstrate analgesic activity in healthy subjects and should therefore not cause long-term adverse effects. The ultraviolet B (UVB) model is a model for inflammatory pain in which three times the minimal erythema dose (3MED) is typically applied to induce sensitization. Based on reports of long-lasting postinflammatory hyperpigmentation (PIH) associated with 3MED, it was decided to investigate the prevalence of PIH among subjects who were previously exposed to 3MED at our research centre. In addition, re-evaluation of the UVB inflammation model using a reduced exposure paradigm (2MED) was performed in healthy subjects. ⋯ Postinflammatory hyperpigmentation is an unwanted long-term side effect associated with the UVB inflammation model using the 3× minimal erythema dose (3MED) paradigm. In contrast, using a 2MED paradigm results in hyperalgesia that is stable for 36 hr and has a lower risk of inducing postinflammatory hyperpigmentation.
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It would be desirable to identify patients with acute low back pain (ALBP) who are at high risk for transition to chronic pain early in the course of their disease. This would enable early preventive or therapeutic interventions. Patients with chronic low back pain (CLBP) display signs of central hypersensitivity. This may contribute to the transition to CLBP. We tested the hypothesis that central hypersensitivity as assessed by quantitative sensory tests predicts transition to CLBP. ⋯ We found no evidence to support a clinically relevant ability of current quantitative sensory tests to predict the transition from acute to CLBP.