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Specialized pro-resolving mediators (SPMs) have demonstrated potent analgesic actions in animal models of pathological pain. The actions of SPMs in acute and chronic itch are currently unknown. Recently, n-3 docosapentaenoic acid (DPA) was found to be a substrate for the biosynthesis of several novel families of SPMs; 3-oxa-PD1n-3 DPA (3-oxa-PD1) is an oxidation-resistant metabolic stable analogue of the n-3 DPA-derived protectin D1 (PD1). Herein, we demonstrate that 3-oxa-PD1 effectively reduces both acute and chronic itch in mouse models. Intrathecal injection of 3-oxa-PD1 (100 ng) reduced acute itch induced by either histamine, chloroquine, or morphine. Furthermore, intrathecal 3-oxa-PD1 effectively reduced chronic itch, induced by cutaneous T cell lymphoma (CTCL), allergic contact dermatitis with dinitrofluorobenzene, and psoriasis by imiquimod. Intratumoral injection of 3-oxa-PD1 also suppressed CTCL-induced chronic itch. Strikingly, this anti-pruritic effect lasted for several weeks after 1-week of intrathecal 3-oxa-PD1 treatment. Whole-cell recordings revealed significant increase in excitatory postsynaptic currents in spinal dorsal horn (SDH) neurons of CTCL mice, but this increase was blocked by 3-oxa-PD1. 3-oxa-PD1 further increased inhibitory postsynaptic currents in SDH neurons of CTCL mice. CTCL increased the spinal levels of lipocalin-2 (LCN2), an itch mediator produced by astrocytes. 3-oxa-PD1 suppressed LCN2 production in CTCL mice and LCN2 secretion in astrocytes. Finally, CTCL-induced anxiety was alleviated by intrathecal 3-oxa-PD1. Our findings suggest that 3-oxa-PD1 potently inhibits acute and chronic itch via regulation of excitatory/inhibitory synaptic transmission and astroglial LCN2 production. Therefore, stable SPM analogs such as 3-oxa-PD1 could be useful to treat pruritus associated with different skin injuries.
Learn More >Psoriasis impacts various aspects of patients' health-related quality of life and is associated with sleep problems. However, research discussing the associations between interleukin-17 blockage therapies and sleep problems in patients with psoriasis is insufficient. We aimed to assess the effectiveness of brodalumab in alleviating sleep problems in real-life patients with plaque psoriasis. This analysis was part of the single-arm, open-label, multicenter, prospective, cohort study, ProLOGUE (study period October 2017-March 2020), which involved Japanese patients with plaque psoriasis. Assessments included correlation of Medical Outcomes Study Sleep Scale-Revised (MOS Sleep-R) scores (Sleep Problems Index-II [SPI-II] and MOS Sleep-R subscale scores) with multiple patient-reported outcome scores and the Psoriasis Area and Severity Index (PASI) at baseline. Additionally, change from baseline in MOS Sleep-R scores was assessed at weeks 12 and 48 of brodalumab treatment. Seventy-three patients were enrolled (male 82.2%, median age 54.0 years). At baseline, the SPI-II score correlated with the Patient Health Questionnaire-8 score (Spearman correlation coefficient [ρ] = -0.474) and weakly correlated with the Itch Numeric Rating Scale (NRS; ρ = -0.366), Skin Pain NRS (ρ = -0.275), and all Treatment Satisfaction Questionnaire for Medication-9 domain scores (ρ = 0.270, ρ = 0.303, and ρ = 0.322 for effectiveness, convenience, and global satisfaction, respectively) but did not correlate with the PASI score. The SPI-II score and MOS Sleep-R subscale scores, except the Snoring score (p = 0.0319), did not significantly change from baseline to week 12 of brodalumab treatment. In conclusion, treatment with brodalumab did not improve overall sleep problems in real-life patients with plaque psoriasis, suggesting that sleep problems require attention in daily clinical practice (Japan Registry of Clinical Trials identifier, jRCTs031180037).
Learn More >To examine the association between chronic spontaneous urticaria (CSU) and interstitial cystitis/bladder pain syndrome (IC/BPS).
Learn More >Three patient-reported outcome (PRO) questionnaires-Worst Pruritus Numerical Rating Scale (WP-NRS), Atopic Dermatitis Symptom Scale (ADerm-SS), and Atopic Dermatitis Impact Scale (ADerm-IS)-were developed to assess the symptoms and impacts of atopic dermatitis (AD). Severity strata for these PROs are needed to aid in their interpretation.
Learn More >Rosacea is a common chronic inflammatory facial skin disorder. Standardized evaluation of the severity and extent of rosacea is important for baseline assessment and treatment effect. The currently used Investigator's Global Assessment (IGA) is unspecific and fails to consider subtypes/phenotypes of rosacea and area involvement. The Rosacea Area and Severity Index (RASI) was developed to give a more nuanced evaluation of rosacea features in four facial skin areas adjusted to the relative importance of each area of the face to obtain an overall severity score.
Learn More >Pruritus in cholestatic liver diseases can be a major burden and dramatically impair the quality of life of those affected. Here, we provide an update on the latest insights into the molecular pathogenesis of and novel therapeutic approaches for cholestasis-associated itch. Endogenous and exogenous small-molecule pruritogen candidates bind to their receptors on unmyelinated itch C-fibres in the skin. Candidate pruritogens in cholestasis include certain lysophospholipids and sulfated progesterone metabolites, among others, whereas total bile acid or bilirubin conjugates seem unlikely to have a dominant role in the pathogenesis of cholestasis-associated pruritus. Transmission of itch signals via primary, secondary and tertiary itch neurons to the postcentral gyrus and activation of scratch responses offer various targets for therapeutic intervention. At present, evidence-based treatment options for pruritus in fibrosing cholangiopathies, such as primary biliary cholangitis and primary sclerosing cholangitis, are the peroxisome proliferator-associated receptor (PPAR) agonist bezafibrate and the pregnane X receptor (PXR) agonist rifampicin. In pruritus of intrahepatic cholestasis of pregnancy, ursodeoxycholic acid is recommended and might be supported in the third trimester by rifampicin if needed. Alternatively, non-absorbable anion exchange resins, such as cholestyramine, can be administered, albeit with poor trial evidence. Liver transplantation for intolerable refractory pruritus has become an extremely rare therapeutic strategy.
Learn More >Psoriasis is a common, chronic immune-mediated skin disease frequently associated to inflammatory and metabolic comorbidities. About 20-30% of patients are affected by moderate-to-severe psoriasis and require a systemic treatment, which include traditional and biological drugs. The objective of this manuscript is to provide criteria for a personalized biological treatment.
Learn More >The neural bases of itchy eye transmission remain unclear compared with those involved in body itch. Here, we show in rodents that the gastrin-releasing peptide receptor (GRPR) of the trigeminal sensory system is involved in the transmission of itchy eyes. Interestingly, we further demonstrate a difference in scratching behaviour between the left and right hindfeet in rodents; histamine instillation into the conjunctival sac of both eyes revealed right-foot biased laterality in the scratching movements. Unilateral histamine instillation specifically induced neural activation in the ipsilateral sensory pathway, with no significant difference between the activations following left- and right-eye instillations. Thus, the behavioural laterality is presumably due to right-foot preference in rodents. Genetically modified rats with specific depletion of expressing neurons in the trigeminal sensory nucleus caudalis of the medulla oblongata exhibited fewer and shorter histamine-induced scratching movements than controls and eliminated the footedness. These results taken together indicate that the -expressing neurons are required for the transmission of itch sensation from the eyes, but that foot preference is generated centrally. These findings could open up a new field of research on the mechanisms of the laterality in vertebrates and also offer new potential therapeutic approaches to refractory pruritic eye disorders.
Learn More >Dry eye disease (DED), arising from various etiologic factors, leads to tear film instability, ocular surface damage, and neurosensory changes. DED causes symptoms such as ocular dryness, burning, itching, pain, and visual impairment. Given their well-established anti-inflammatory effects, topical steroid preparations have been widely used as a short-term treatment option for DED. Because of potential risks of ocular hypertension, cataracts, and infections associated with the long-term use of topical steroids, published trials comparing the efficacy and safety of topical steroids (versus placebo) have mostly been of short duration (three to eight weeks).
Learn More >A body of research has examined the role of fatty acid (FA), vitamin, and mineral supplementation as adjunctive treatment for atopic dermatitis (AD); however, results are conflicting and concrete recommendations are lacking. The objective of this study is to highlight the role of these nutrients in alleviating AD severity and provide the clinician with consolidated information that can be used to make recommendations to the pediatric patient and caretaker, where this topic is of high interest.
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