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The monoiodoacetate-induced rat model of osteoarthritis knee pain is widely used. However, there are between-study differences in the pain behavioural endpoints assessed and in the dose of intraarticular monoiodoacetate administered. This study evaluated the robustness of gait analysis as a pain behavioural endpoint in the chronic phase of this model, in comparison with mechanical hyperalgesia in the injected (ipsilateral) joint and development of mechanical allodynia in the ipsilateral hind paws. Groups of Sprague-Dawley rats received a single intraarticular injection of monoiodoacetate at 0.5, 1, 2 or 3 mg or vehicle (saline) into the left (ipsilateral) knee joint. An additional group of rats were not injected (naïve group). The pain behavioural methods used were gait analysis, measurement of pressure algometry thresholds in the ipsilateral knee joints, and assessment of mechanical allodynia in the ipsilateral hind paws using von Frey filaments. These pain behavioural endpoints were assessed premonoiodoacetate injection and for up to 42-days postmonoiodoacetate injection in a blinded manner. Body weights were also assessed as a measure of general health. Good general health was maintained as all rats gained weight at a similar rate for the 42-day study period. In the chronic phase of the model (days 9-42), intraarticular monoiodoacetate at 3 mg evoked robust alterations in multiple gait parameters as well as persistent mechanical allodynia in the ipsilateral hind paws. For the chronic phase of the monoiodoacetate-induced rat model of osteoarthritis knee pain, gait analysis, such as mechanical allodynia in the ipsilateral hind paws, is a robust pain behavioural measure.
Learn More >To provide a consensus statement describing best practices and evidence regarding head and neck cancer survivorship.
Learn More >Brachial plexus avulsion significantly increased brain-derived neurotrophic factor (BDNF) release in the spinal cord. Here we investigated the involvement of the BDNF-TrkB-KCC2 pathway in neuropathic pain caused by BPA injury. We hypothesized that activation of BDNF-TrkB may inhibit neuronal excitability by downregulating KCC2 to maintain a high intracellular Cl-concentration. We established a neuropathic pain rat model by avulsion of the lower trunk brachial plexus, and investigated the effects of the TrkB-specific antibody K-252a on the expression of BDNF, TrkB, and KCC2.
Learn More >This study was designed to characterize the type of interaction (subadditive, additive, or synergistic) after simultaneous administration by two different routes (intraperitoneal plus peripheral local) of the same nonsteroidal anti-inflammatory drugs (NSAID) ketorolac and indomethacin or paracetamol. The antinociceptive effects of locally or intraperitoneally delivery of NSAIDs or paracetamol, and the simultaneous administration by the two routes at fixed-dose ratio combination were evaluated using the formalin test. Pain-related behavior was quantified as the number of flinches of the injected paw. Isobolographic analysis was used to characterize the interaction between the two routes. ED30 values were estimated for individual drugs, and isobolograms were constructed. Ketorolac, indomethacin, or paracetamol and fixed-dose ratio combinations produced a dose-dependent antinociceptive effect in the second but not in the first phase of the formalin test. The analysis of interaction type after simultaneous administration by the two routes the same NSAID or paracetamol (on basis of their ED30), revealed that the simultaneous administration of ketorolac or paracetamol was additive and for indomethacin was synergistic. Since the mechanisms underlying the additive effect of ketorolac or paracetamol and the synergistic effect of indomethacin were not explored; it is possible that the peripheral and central mechanism is occurring at several anatomical sites. The significance of these findings for theory and pain pharmacotherapy practice indicates that the combination of one analgesic drug given simultaneously by two different administration routes could be an additive or it could lead to a synergistic interaction.
Learn More >Vulvodynia is a debilitating disorder which can prove extremely difficult to treat. Neuromodulation is increasingly becoming a frontline therapy in various chronic pain syndromes. We present a relatively simple surgical technique utilizing targeted neuromodulation leading to the successful treatment of vulvodynia.
Learn More >Investigating the disproportionate rates of chronic pain and their related comorbidities between Black and non-Hispanic White (White) individuals is a growing area of interest, both in the healthcare community and in general society. Researchers have identified racial differences in chronic pain prevalence and severity, but still very little is known about the mechanisms underlying them. Current explanations for these differences have primarily focused on socioeconomic status and unequal healthcare between races as causal factors. Whereas these factors are informative, a racial gap still exists between Black and White individuals when these factors are controlled for. One potential cause of this racial gap in chronic pain is the differences in nutrition and dietary intake between groups. Certain foods play a key role in the inflammatory and oxidative stress pathways in the human body and could potentially influence the severity of the pain experience. Here, we review the previous literature on the surrounding topics and propose a potential mechanism to explain racial differences in the chronic pain population, based on established racial differences in diet and oxidative stress.
Learn More >To design and evaluate, through a human-centered design approach, a multispeciality clinic for patients with central sensitization syndromes that combined virtual previsit consultations, traditional face-to-face appointments, and technology-enabled educational programming.
Learn More >Pain catastrophizing (PC), defined as tendency to describe pain in more exaggerated terms, to ruminate more or to feel helpless about it. Main objective was to illuminate PC in rheumatoid arthritis (RA), psoriatic arthritis (PsA) and axial spondyloarthritis (axSpA), revealing its prevalence and associations from a biopsychosocial perspective, including its association with health-related quality of life (HRQoL). Measures reflecting the biological, social and psychological perspective were recorded in RA, PsA and axSpA outpatients. Biological variables including demographics, disease activity and patient reported outcomes (PROs) along with variables reflecting psychological and social domains were collected. RAND12 questionnaire was used to explore HRQoL and standardized questionnaire was used to reveal pain catastrophizing score (PCS). 1229 patients were recruited (RA 580, PsA 394, axSpA 255). Mean (SD) PCS were for RA 1.88 (1.39), PsA 2.06 (1.45) and axSpA 2.27 (1.37). Proportion of pain catastrophizers (score ≥ 4) was not statistically different between RA (10.5%), PsA (12.7%) and axSpA (15.3%). Across all diagnoses, variables reflecting biological subjective domain explained more PCS variability (adjusted R 35.3-49.9%) than psychological (28.4-33.6%), social (22.4-28.4%) and biological objective (4.3-9.9%) domains. HRQoL was significantly lower in pain catastrophizers across all diagnoses. No substantial differences in proportion of pain catastrophizers between RA, PsA and axSpA patients were found. Higher PCS (score ≥ 4) was best explained by biological subjective measures and corresponded with inferior HRQoL in all diseases. Several biological objectives, psychological and social measures were also associated with higher PCS.
Learn More >. Adherence to treatment recommendations is critical for optimising quality of life for individuals with chronic pain, however adherence rates are low. This study explores the role that significant others are perceived to play in supporting or impeding treatment adherence, as well as examining patient views of the impact of their adherence regimes on their significant others.. 25 treatment seeking adults with chronic pain, who were currently living with a romantic partner or adult family member, took part in individual semi-structured interviews. Interviews were transcribed verbatim and analysed using thematic analysis. Three treatment adherence support themes emerged: social support (emotional, instrumental), positive social control, and supporting autonomy. Participants did not perceive significant others as having any negative influence on their adherence. By contrast, patients perceived that their adherence behaviors had both positive and negative effects on their significant others.. These data present an encouraging perspective on the interpersonal context of coping with chronic pain. Significant others facilitated adherence in a range of ways. Future research identifying how best to integrate significant other support into patient self-management programs is needed, in order to lift the poor treatment adherence rates that are noted in the literature.
Learn More >The present study investigated whether illness cognitions mediated the relationship between caregiving demands and positive and negative indicators of adjustment in partners of patients with chronic pain.
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