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Low back pain (LBP) is the leading cause of disability and a global public health concern. Studies indicate that pain self-efficacy is associated with the development of disability in chronic LBP (CLBP) patients. The Pain Self-Efficacy Questionnaire (PSEQ) is a commonly used questionnaire to assess pain self-efficacy in patients with CLBP. It is essential to examine the psychometric properties of the PSEQ in the population in which it is to be used. Thus, the aim of this study is to evaluate the reliability and smallest detectable change of the Danish version of the Pain Self-Efficacy Questionnaire (PSEQ-DK) in patients with CLBP before implementing it as an outcome measure in an inpatient rehabilitation context.
Learn More >Human immunodeficiency virus (HIV) infection and antiretroviral therapy can independently induce HIV-associated neuropathic pain (HIV-NP). There is a dearth of drugs or therapeutic modalities that can alleviate HIV-NP. Smoked cannabis has been reported to improve pain measures in patients with neuropathic pain. Cannabis, phytocannabinoids, and the endocannabinoids such N-arachidonoylethanolamine (anandamide; AEA) and 2-arachidonoylglycerol (2-AG), produce some of their effects via cannabinoid receptors (CBRs). Endocannabinoids are degraded by various enzymes such as fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase. We searched PubMed, Google Scholar, clinicaltrials.gov and clinicaltrialsregister.eu using various key words and their combinations for published papers that studied HIV-NP and cannabis, cannabinoids, or endocannabinoids up to 27th December 2020. All original research articles that evaluated the efficacy of molecules that modulate the endocannabinoid system (ECS) for the prevention and/or treatment of pain in HIV-NP animal models and patients with HIV-NP were included. The PubMed search produced a total of 117 articles, whereas the Google Scholar search produced a total of 9467 articles. Amongst the 13 articles that fulfilled the inclusion criteria 11 articles were found in both searches whereas 2 articles were found in Google Scholar only. The clinicaltrials.gov and clinicaltrialsregister.eu searches produced five registered trials of which three were completed and with results. Ten preclinical studies found that the endocannabinoids (2-AG and AEA), synthetic mixed CB1R/CB2R agonist WIN 55,212-2, a CB2R-selective phytocannabinoid β-caryophyllene, synthetic CB2R-selective agonists (AM1710, JWH015, JWH133 and Gp1a, but not HU308); FAAH inhibitors (palmitoylallylamide, URB597 and PF-3845) and a drug combination of indomethacin plus minocycline, which produces its effects in a CBR-dependent manner, either prevented the development of and/or attenuated established HIV-NP. Two clinical trials demonstrated greater efficacy of smoked cannabis over placebo in alleviating HIV-NP, whereas another clinical trial demonstrated that cannabidivarin, a cannabinoid that does not activate CBRs, did not reduce HIV-NP. The available preclinical results suggest that targeting the ECS for prevention and treatment of HIV-NP is a plausible therapeutic option. Clinical evidence shows that smoked cannabis alleviates HIV-NP. Further research is needed to find out if non-psychoactive drugs that target the ECS and are delivered by other routes than smoking could be useful as treatment options for HIV-NP.
Learn More >Despite the biopsychosocial underpinnings of chronic noncancer pain, relatively little is known about the contribution of psychosocial factors to chronic cancer pain. The authors aimed to characterize associations between biopsychosocial factors and pain and opioid use among individuals with chronic pain and cancer.
Learn More >Chronic pain is the leading cause of disability worldwide and is commonly associated with comorbid disorders. However, the role of diet in chronic pain is poorly understood. Of particular interest is the Western-style diet, enriched with ω-6 polyunsaturated fatty acids (PUFAs) that accumulate in membrane phospholipids and oxidise into pronociceptive oxylipins. Here we report that mice administered an ω-6 PUFA-enriched diet develop persistent nociceptive hypersensitivities, spontaneously active and hyper-responsive glabrous afferent fibres and histologic markers of peripheral nerve damage reminiscent of a peripheral neuropathy. Linoleic and arachidonic acids accumulate in lumbar dorsal root ganglia, with increased liberation via elevated phospholipase (PLA)2 activity. Pharmacological and molecular inhibition of PLA2G7 or diet reversal with high levels of ω-3 PUFAs attenuate nociceptive behaviours, neurophysiologic abnormalities and afferent histopathology induced by high ω-6 intake. Additionally, ω-6 PUFA accumulation exacerbates allodynia observed in preclinical inflammatory and neuropathic pain models and is strongly correlated with multiple pain indices of clinical diabetic neuropathy. Collectively, these data reveal dietary enrichment with ω-6 PUFAs as a new aetiology of peripheral neuropathy and risk factor for chronic pain and implicate multiple therapeutic considerations for clinical pain management.
Learn More >Primary sensory neurons are generally considered the only source of dorsal horn calcitonin gene-related peptide (CGRP), a neuropeptide critical to the transmission of pain messages. Using a tamoxifen-inducible transgenic mouse, here we identified a distinct population of CGRP-expressing excitatory interneurons in lamina III of the spinal cord dorsal horn and trigeminal nucleus caudalis. These interneurons have spine-laden, dorsally directed, dendrites, and ventrally directed axons. As under resting conditions, CGRP interneurons are under tonic inhibitory control, neither innocuous nor noxious stimulation provoked significant Fos expression in these neurons. However, synchronous, electrical non-nociceptive Aβ primary afferent stimulation of dorsal roots depolarized the CGRP interneurons, consistent with their receipt of a VGLUT1 innervation. On the other hand, chemogenetic activation of the neurons produced a mechanical hypersensitivity in response to von Frey stimulation, whereas their caspase-mediated ablation led to mechanical hyposensitivity. Finally, after partial peripheral nerve injury, innocuous stimulation (brush) induced significant Fos expression in the CGRP interneurons. These findings suggest that CGRP interneurons become hyperexcitable and contribute either to ascending circuits originating in deep dorsal horn or to the reflex circuits in baseline conditions, but not in the setting of nerve injury.
Learn More >Storytelling is a distinctive human characteristic that may have played a fundamental role in humans' ability to bond and navigate challenging social settings throughout our evolution. However, the potential impact of storytelling on regulating physiological and psychological functions has received little attention. We investigated whether listening to narratives from a storyteller can provide beneficial effects for children admitted to intensive care units. Biomarkers (oxytocin and cortisol), pain scores, and psycholinguistic associations were collected immediately before and after storytelling and an active control intervention (solving riddles that also involved social interaction but lacked the immersive narrative aspect). Compared with the control group, children in the storytelling group showed a marked increase in oxytocin combined with a decrease in cortisol in saliva after the 30-min intervention. They also reported less pain and used more positive lexical markers when describing their time in hospital. Our findings provide a psychophysiological basis for the short-term benefits of storytelling and suggest that a simple and inexpensive intervention may help alleviate the physical and psychological pain of hospitalized children on the day of the intervention.
Learn More >The current opioid epidemic warrants a better understanding of genetic and environmental factors that contribute to opioid addiction. Here we report an increased prevalence of vitamin D (VitD) deficiency in patients diagnosed with opioid use disorder and an inverse and dose-dependent association of VitD levels with self-reported opioid use. We used multiple pharmacologic approaches and genetic mouse models and found that deficiencies in VitD signaling amplify exogenous opioid responses that are normalized upon restoration of VitD signaling. Similarly, physiologic endogenous opioid analgesia and reward responses triggered by ultraviolet (UV) radiation are repressed by VitD signaling, suggesting that a feedback loop exists whereby VitD deficiency produces increased UV/endorphin-seeking behavior until VitD levels are restored by cutaneous VitD synthesis. This feedback may carry the evolutionary advantage of maximizing VitD synthesis. However, unlike UV exposure, exogenous opioid use is not followed by VitD synthesis (and its opioid suppressive effects), contributing to maladaptive addictive behavior.
Learn More >Post-traumatic headache is a common sequela of traumatic brain injury and is classified as a secondary headache disorder. In the past 10 years, considerable progress has been made to better understand the clinical features of this disorder, generating momentum to identify effective therapies. Post-traumatic headache is increasingly being recognised as a heterogeneous headache disorder, with patients often classified into subphenotypes that might be more responsive to specific therapies. Such considerations are not accounted for in three iterations of diagnostic criteria published by the International Headache Society. The scarcity of evidence-based approaches has left clinicians to choose therapies on the basis of the primary headache phenotype (eg, migraine and tension-type headache) and that are most compatible with the clinical picture. A concerted effort is needed to address these shortcomings and should include large prospective cohort studies as well as randomised controlled trials. This approach, in turn, will result in better disease characterisation and availability of evidence-based treatment options.
Learn More >While the 2016 US Centers for Disease Control and Prevention (CDC) guideline for prescribing opioids for chronic pain was not intended to address postoperative pain management, observers have noted the potential for the guideline to have affected postoperative opioid prescribing.
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