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Allergic conjunctivitis is a chronic inflammatory disease that is characterized by severe itch in the conjunctiva, but how neuro-immune interactions shape the pathogenesis of severe itch remains unclear. We identified a subset of memory-type pathogenic Th2 cells that preferentially expressed Il1rl1-encoding ST2 and Calca-encoding calcitonin-gene-related peptide (CGRP) in the inflammatory conjunctiva using a single-cell analysis. The IL-33-ST2 axis in memory Th2 cells controlled the axonal elongation of the peripheral sensory C-fiber and the induction of severe itch. Pharmacological blockade and genetic deletion of CGRP signaling in vivo attenuated scratching behavior. The analysis of giant papillae from patients with severe allergic conjunctivitis revealed ectopic lymphoid structure formation with the accumulation of IL-33-producing epithelial cells and CGRP-producing pathogenic CD4 T cells accompanied by peripheral nerve elongation. Thus, the IL-33-ST2-CGRP axis directs severe itch with neuro-reconstruction in the inflammatory conjunctiva and is a potential therapeutic target for severe itch in allergic conjunctivitis.
Learn More >Dysregulation of circular RNAs (circRNAs) has been reported to be functionally associated with chronic pain, but it is unknown whether and how circRNAs participate in visceral hypersensitivity. The expression of circKcnk9 was increased in spinal neurons of IBS-like rats. ShcircKcnk9 attenuated visceral hypersensitivity and inhibited c-Fos expression in IBS-like rats, whereas overexpression of spinal circKcnk9 induced visceral hypersensitivity and increased c-Fos expression in control rats. Furthermore, circKcnk9 was found to act as a miR-124-3p sponge. MiR-124-3p antagomir restored pain responses downregulated by shcircKcnk9 in IBS-like rats. Finally, the signal transducer and activator of transcription 3 (STAT3), validated as a target of miR-124-3p, could play a critical role in visceral hypersensitivity by regulating NSF/GluR2. Perspective. Spinal circKcnk9 functions as a miR-124-3p sponge to promote visceral hypersensitivity by regulating the STAT3/NSF/GluR2 pathway. This pathway might provide a novel epigenetic mechanism of visceral hypersensitivity and a potential circRNA therapeutic target to IBS.
Learn More >Chronic pain is frequently comorbid with depression. However, the mechanisms underlying chronic pain-induced depression remain unclear. Here, we found that DNA methyltransferase 1 (DNMT1) was upregulated in the central amygdala (CeA) of spared nerve injury (SNI)-induced chronic pain-depression rats, and knockdown of DNMT1 could improve the depression-like behaviors in SNI rats. Additionally, a panel of differentially expressed lncRNAs, including 38 upregulated and 12 downregulated lncRNAs, were identified by microarray analysis. Bioinformatics analysis suggested that the upregulated lncRNA XR_351665 was the upstream molecule to regulate DNMT1 expression. The knockdown of XR_351665 significantly alleviated the depression-like behaviors in SNI rats, whereas overexpression of XR_351665 induced the depression-like behaviors in naïve rats. Further mechanism-related researches uncovered that XR_351665 functioned as a competing endogenous RNA (ceRNA) to upregulate DNMT1 by competitively sponging miR-152-3p, and subsequently promoted the development of chronic pain-induced depression. Our findings suggest that lncRNA XR_351665 is involved in the development of chronic pain-induced depression by upregulating DNMT1 via sponging miR-152-3p. These data provide novel insight into understanding the pathogenesis of chronic pain-induced depression and identify a potential therapeutic target.
Learn More >To compare patient-reported outcomes (PROMs) following surgery for degenerative cervical myelopathy (DCM) among patients with rheumatoid arthritis (RA) or ankylosing spondylitis (AS) versus those without rheumatic diseases.
Learn More >The diagnosis of axial spondyloarthritis (axSpA) is hampered by diagnostic delay. Computed Tomography (CT) undertaken for non-musculoskeletal (MSK) indications in patients with inflammatory bowel disease (IBD) offers an opportunity to identify sacroiliitis for prompt rheumatology referral. The study aims to identify what proportion of IBD patients who underwent abdominopelvic CT for non-MSK indications have axSpA and explore the role of a standardised screening tool to prospectively identify axSpA on imaging.
Learn More >Total knee arthroplasty (TKA) is among the most performed orthopaedic surgeries in the United States with at least 1,000,000 cases performed per year. Dissatisfaction following TKA has often been reported as 20% or more, with a multitude of causes including sociodemographic, preoperative, and postoperative factors. The purpose of this study was to reexamine the rate and causes of dissatisfaction following TKA.
Learn More >The multiple comorbidities & dimensions of chronic pain present a formidable challenge in disentangling its aetiology. Here, we performed genome-wide association studies of eight chronic pain types using UK Biobank data (N=4,037-79,089 cases; N=239,125 controls), followed by bivariate linkage disequilibrium-score regression and latent causal variable analyses to determine (respectively) their genetic correlations and genetic causal proportion (GCP) parameters with 1,492 other complex traits. We report evidence of a shared genetic signature across chronic pain types as their genetic correlations and GCP directions were broadly consistent across an array of biopsychosocial traits. Across 5,942 significant genetic correlations, 570 trait pairs could be explained by a causal association (|GCP| > 0.6; 5% false discovery rate), including 82 traits affected by pain while 410 contributed to an increased risk of chronic pain (cf. 78 with a decreased risk) such as certain somatic pathologies (e.g., musculoskeletal), psychiatric traits (e.g., depression), socioeconomic factors (e.g., occupation) and medical comorbidities (e.g., cardiovascular disease). This data-driven phenome-wide association analysis has demonstrated a novel and efficient strategy for identifying genetically supported risk & protective traits to enhance the design of interventional trials targeting underlying causal factors and accelerate the development of more effective treatments with broader clinical utility. PERSPECTIVE: Through large-scale phenome-wide association analyses of >1,400 biopsychosocial traits, this article provides evidence for a shared genetic signature across eight common chronic pain types. It lays the foundation for further translational studies focused on identifying causal genetic variants and pathophysiological pathways to develop novel diagnostic & therapeutic technologies and strategies.
Learn More >There have been several recent calls to "re-think chronic pain" in response to the growing awareness of social inequities that impact the prevalence of chronic pain and its management. This in turn has resulted in new explorations of suffering as it relates to pain. While laudable, many of these clinically oriented accounts are abstract and often fail to offer a critical theoretical understanding of social and structural inequities. To truly rethink pain, we must also reconsider suffering, beginning in the everyday expert knowledge of people with chronic pain who can offer insights in relation to their bodies and also the organization of the social circumstances in which they live. Our team undertook a sociological approach known as institutional ethnography (IE) to explicate the work of people in managing lives beset by chronic pain and the inequities that stem from marginalization. In keeping with our critical paradigm, we describe participant accounts as situated, rather than lived, to de-emphasize the individual in favour of the social and relational. Through our analysis, we offer a new concept of "chronic struggle" to capture how pain, illness, economic deprivation, and suffering constitute a knot of experience that people living with chronic pain are obliged to simplify in order to fit existing logics of medicine. Our goal is to identify the social organization of chronic pain care which underpins experience in order to situate the social as political rather than medical or individual. PERSPECTIVE: This article explicates the health work of people living with chronic pain and marginalization, drawing on their situated experience. We offer the concept of chronic struggle as a conceptualization that allows us to bring into clear view the social organization of chronic pain in which the social is visible as political and structural rather than medical or individual.
Learn More >Migraine is a common neuronal disorder characterized by recurrent episodes of headache associated with a higher prevalence in women than men. Several risk factors have been associated with migraine disease as genetic factors, gender, and age. Although understanding migraine pathophysiology is improved, it has been reported that NOD-like receptor protein 3 (NLRP3) inflammasome pathway overactivation can contribute to migraine progression. Therefore, the aim of this study was to investigate the effect of BAY-117082, an NLRP3 inflammasome inhibitor, in a mouse model of nitroglycerin (NTG)-induced migraine. The in vivo model of migraine was induced by intraperitoneal (i.p) injection of NTG (dose of 10 mg/kg). Mice were treated intraperitoneally with BAY-117082 at doses of 1 mg/kg, 5 mg/kg, and 10 mg/kg, 5 min following NTG injection. After 4 h of NTG injection, the whole brain tissue with the rostral spinal cord were collected and used to perform further analysis. Our results demonstrated that BAY-117082 treatments (5 mg/kg and 10 mg/kg) reduced pain attacks, hyperalgesia and photophobia more in female mice NTG-induced. Moreover, the treatment with BAY-117082 significantly reduced histological damage in the trigeminal nerve nucleus in female mice accordingly to significantly decreased in NLRP3 complex components expression levels such as ASC, IL-1β, IL-18, caspase-1 and TNF-α levels. Additionally, the treatment with BAY-117082 at both higher doses significantly modulated CREB/Erk/Akt pathways strictly correlated to the expression of neurotrophic factors. Taken together, obtained results confer new insight into the role of the NLRP3 inflammasome pathway in migraine pathogenesis, suggesting that BAY-117082 could be considered a novel strategy therapeutics for migraine treatment despite unconventional drug use.
Learn More >Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels have been focused on as a potential therapeutic target for inflammatory and neuropathic pain in rodent models. However, roles of HCN channels in human pain states have been scarcely investigated. We evaluated analgesic effects of 2-day administration of ivabradine, the only clinically available HCN channel blocker, on a capsaicin pain model in a randomized, double-blinded, placebo-controlled, crossover study. Twenty healthy adult subjects (18 males, 2 females) received ivabradine (5-7.5 mg) or a placebo 3 times in 2 days. Then capsaicin (0.5%) was topically applied on the volar forearm for 30 min. The primary outcome was capsaicin-induced spontaneous pain. The secondary outcomes included heat-pain threshold (HPT), flare size, and areas of secondary punctate mechanical hyperalgesia (PMH) and secondary dynamic mechanical allodynia (DMA). There was no significant difference in spontaneous pain (p = 0.7479), HPT (p = 0.7501), area of PMH (p = 0.1052) or flare size (p = 0.5650) at 30 min after capsaicin application between the groups. In contrast, the area of DMA in the ivabradine group was significantly smaller (p < 0.001) than that in the placebo group. HCN channels may be differentially involved in the various pain signal transmission pathways in humans.
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