Diospyros lotus leaf extract and its main component myricitrin inhibit itch­related IL­6 and IL­31 by suppressing microglial inflammation and microglial­mediated astrocyte activation.

Diospyros lotus has been traditionally used in Asia for medicinal purposes, exhibiting a broad spectrum of pharmacological effects including antioxidant, neuroprotective and anti­inflammatory properties. While the anti­itch effect of D. lotus leaves has been reported, studies on the detailed mechanism of action in microglia and astrocytes, which are members of the central nervous system, have yet to be revealed. The present study aimed to investigate effects of D. lotus leaf extract (DLE) and its main component myricitrin (MC) on itch­related cytokines and signaling pathways in lipopolysaccharide (LPS)­stimulated microglia. The effect of DLE and MC on activation of astrocyte stimulated by microglia was also examined. Cytokine production was evaluated through reverse transcription PCR and western blot analysis. Signaling pathway was analyzed by performing western blotting and immunofluorescence staining. The effect of microglia on astrocytes activation was evaluated via western blotting for receptors, signaling molecules and itch mediators and confirmed through gene silencing using short interfering RNA. DLE and MC suppressed the production of itch­related cytokine IL­6 and IL­31 in LPS­stimulated microglia. These inhibitory effects were mediated through the blockade of NF­κB, MAPK and JAK/STAT pathways. In astrocytes, stimulation by microglia promoted the expression of itch­related molecules such as oncostatin M receptor, interleukin 31 receptor a, inositol 1,4,5­trisphosphate receptor 1, lipocalin­2 (LCN2), STAT3 and glial fibrillary acidic protein. However, DLE and MC significantly inhibited these receptors. Additionally, astrocytes stimulated by microglia with IL­6, IL­31, or both genes silenced did not show activation of LCN2 or STAT3. The findings of the present study demonstrated that DLE and MC could suppress pruritic activity in astrocytes induced by microglia­derived IL­6 and IL­31. This suggested the potential of DLE and MC as functional materials capable of alleviating pruritus.

Neuroinflammation evoked mechanisms for neuropathic itch in the spared nerve injury mouse model of neuropathic pain.

A large portion of neuropathic pain suffering patients may also concurrently experience neuropathic itch, with a negative impact on the quality of life. The limited understanding of neuropathic itch and the low efficacy of current anti-itch therapies dictate the urgent need of a better comprehension of molecular mechanisms involved and development of relevant animal models. This study was aimed to characterize the itching phenotype in a model of trauma-induced peripheral neuropathy, the spared nerve injury (SNI), and the molecular events underlying the overlap with the nociceptive behavior. SNI mice developed hyperknesis and spontaneous itch 7-14 days after surgery that was prevented by gabapentin treatment. Itch was associated with pain hypersensitivity, loss of intraepidermal nerve fiber (IENF) density and increased epidermal thickness. In coincidence with the peak of scratching behavior, SNI mice showed a spinal overexpression of IBA1 and GFAP, microglia and astrocyte markers respectively. An increase of the itch neuropeptide B-type natriuretic peptide (BNP) in NeuN+ cells, of its downstream effector interleukin 17 (IL17) along with increased pERK1/2 levels occurred in the spinal cord dorsal horn and DRG. A raise in BNP and IL17 was also detected at skin level. Stimulation of HaCat cells with conditioned medium from BV2-stimulated SH-SY5Y cells produced a dramatic reduction of HaCat cell viability. This study showed that SNI mice might represent a model for neuropathic itch and pain. Collectively, our finding suggest that neuropathic itch might initiate at spinal level, then affecting skin epidermis events, through a glia-mediated neuroinflammation-evoked BNP/IL17 mechanism.

Evaluating the safety and efficacy of seladelpar for adults with primary biliary cholangitis.

INTRODUCTION: Seladelpar (MBX-8025) is a once-daily administered highly specific PPAR-δ agonist in Phase 3 and extension trials for use in patients with primary biliary cholangitis (PBC). AREAS COVERED: This review provides background on current treatment options for PBC, and summarizes clinical trial data regarding the safety and effectiveness of seladelpar within the context of these treatments. EXPERT OPINION: Clinical trials results demonstrate the safety and tolerability of seladelpar use for PBC, including in patients with cirrhosis. The primary composite endpoint (ALP <1.67 times ULN, decrease ≥ 15% from baseline, and TB ≤ULN) was met in 61.7% of the patients treated with seladelpar and in 20% receiving placebo (p < 0.001). Moreover, pruritus - a cardinal and often intractable symptom of PBC - was improved with seladelpar treatment, as were overall quality of life measurements. Improvements in markers of inflammation were likewise observed. These biochemical and clinical findings therefore represent landmark developments in PBC treatment and offer a therapeutic option for PBC.

Quality of Care and Management of Atopic Dermatitis Across Different Levels of Healthcare-A Survey-Based Patient Experience.

Atopic dermatitis (AD) is a chronic and fluctuating disease. Optimal management of AD and related comorbidities requires seamless coordination across multiple layers of the healthcare system. The objective of this survey was to explore patients' experiences with current management of AD. Out of 251 responders to this anonymous survey, 76% reported to have moderate or severe AD. Sixty-nine percent with moderate and 45% with severe AD were followed up at primary care level only. Use of advanced systemic treatment options was rare, and the majority experienced itch (97%), dry skin, rash, negative impact on self-esteem and comorbidities despite ongoing treatment. Only 36% received a treatment plan, more often in secondary (78.3%) than primary care (25.0%). Forty-three percent did not know who was responsible for their follow-up and 54% felt no one was responsible. Treatment options were commonly not known or understood. The survey results demonstrate undertreatment, lack of a holistic approach for management of AD. A national pathway including clear referral criteria and timelines can streamline management of AD across multiple levels of the healthcare system.

Patient perspective on symptoms of Notalgia paresthetica: subpopulation results from the Neuropathic Itch Patient Survey (NIRVE).

Background: Notalgia paresthetica (NP) is a form of neuropathic itch characterized by recurrent itch in the mid back. Much about NP remains unclear, especially the patient experience.Objectives: The Neuropathic Itch Patient Survey (NIRVE) was a global, online survey conducted to better characterize the symptom burden of neuropathic itch from the patient perspective.Patients and methods: This report focuses on the symptom burden of the subpopulation of NIRVE participants with a self-reported diagnosis of NP (N = 91). Respondents reported visiting a median of 2 healthcare providers (HCPs) for their symptoms before receiving an accurate diagnosis of NP.Results: The most common cutaneous symptoms ever experienced were itch/pruritus, sensitive skin, painful or raw skin, numbness, and tingling. The symptoms reported by the most respondents as currently being experienced included itch/pruritus, numbness, painful or raw skin, tingling, and burning or hot sensation. Of patients currently experiencing symptoms, numbness and itch/pruritus were ranked as the most intense, followed by tingling, burning or hot sensation, and then painful or raw skin. Most patients consult multiple healthcare providers (HCPs) before receiving a diagnosis for their condition.Conclusion: Itch is overwhelmingly the most prevalent symptom of the condition, although half of patients also report experiencing sensitive skin, painful or raw skin, numbness, or tingling.

Investigating the relationship between chronic pruritus and fibromyalgia: an evaluation of 200 patients.

Pruritus is a common complaint in dermatology outpatient clinics. It is defined as chronic pruritus if the symptoms last 6 weeks or longer. Fibromyalgia is a chronic, extensive pain syndrome that is well-known for its clinical signs, such as exhaustion, sleeping disorders, and some other pain symptoms. In the present study, it was investigated whether chronic pruritus patients were accompanied by fibromyalgia. The study included 100 patients with chronic pruritus and 100 controls without dermatological disease. All of the individuals were first evaluated in the dermatology clinic, and the patients having any musculoskeletal symptoms were then referred to a physiatrist in terms of accompanying fibromyalgia syndrome. Fibromyalgia was detected in 29 (29%) of 100 chronic pruritus patients and 6 (6%) of 100 patients in the control group. There was a statistically significant difference between the two groups regarding accompanying FM (p < 0.001). In the chronic pruritus group, pruritus severity, according to VAS and the four-item itch questionnaire score, was statistically significantly higher in patients with fibromyalgia than in patients without fibromyalgia (p = 0.027, p = 0.002, respectively). In addition, the number of patients with severe/very severe chronic pruritus was statistically significantly higher in the group accompanied by fibromyalgia (p = 0.023). It may be suggested that fibromyalgia is a frequent disease that can accompany chronic pruritus. Clinicians should keep in mind that there is a possibility of the coexistence of both diseases. This study calls attention to the complex relationship between chronic itch and pain.

Lasmiditan ameliorates serotonergic itch in mice: Possible involvement of 5-HT1F receptors.

Previously, some allergic conditions involving pruritus have been linked to migraine, raising the possibility that migraine and itching may be governed by similar underlying mechanisms. We aimed to investigate the efficacy of Lasmiditan, a highly selective agonist of the 5-hydroxytryptamine 1F (5-HT1F) receptor and a recently approved medication for the treatment of migraine headaches, in ameliorating serotonergic itching. Forty animals were employed in the present study (n = 40). Eight animals were randomly assigned to each of the following study groups (n = 8, in each group): (1) "Normal Saline": This group was given intradermal injections of normal saline (2) "5-HT": The animals were injected with intradermal 5-HT, which was used to induce itching. (3) "Lasmiditan 0.3", "Lasmiditan 1", and "Lasmiditan 3" groups: injected with 5-HT as well as intraperitoneal Lasmiditan at different dose levels (0.3, 1, and 3 mg/kg, respectively). Scratching behavior was recorded for 60 min, and the skin tissue of three mice was sampled at the end of the behavioral experiment to assess the levels of TLR-4, IL-31, 5-HT1F receptor, CGRP & TRPV4. In the present study, we found that Lasmiditan when administered at 1 mg/kg effectively reduced serotonin-induced itching compared to the "5-HT" group (P < 0.0001). Following the administration of Lasmiditan (1 mg/kg), the expression levels of the 5-HT1F receptor significantly increased (P < 0.01). Further, the levels of TLR-4, IL-31, CGRP & TRPV4 were substantially reduced upon the administration of Lasmiditan (1 mg/kg). We found that Lasmiditan is effective in reducing serotonergic itch in mice through its interaction with the 5-HT1F receptor in the skin tissue of mice.

More Time Spent with Clear Skin and No Itch with Upadacitinib versus Dupilumab for Atopic Dermatitis.

INTRODUCTION: Atopic dermatitis (AD), with its hallmark symptoms of pruritus and skin lesions, often impairs patients' quality of life. We assessed time spent with clear/almost clear skin and no/minimal itch during upadacitinib treatment versus placebo or dupilumab among patients with moderate-to-severe AD. METHODS: This analysis consisted of a post hoc analysis of Measure Up 1 (NCT03569293), Measure Up 2 (NCT03607422), and Heads Up (NCT03738397). Measure Up 1 and 2 were replicate, randomized, double-blind, placebo-controlled phase 3 studies with patients randomized (1:1:1) to once-daily oral upadacitinib 15 mg, upadacitinib 30 mg, or placebo for 16 weeks. Heads Up was a head-to-head, randomized, double-blind, double-dummy, phase 3b study with patients randomized (1:1) to upadacitinib 30 mg or subcutaneous dupilumab 300 mg for 24 weeks. Skin clearance was assessed with the Eczema Area and Severity Index (EASI) at baseline, weeks 1, 2, and 4, and every 4 weeks thereafter. Itch was assessed using the Worst Pruritus Numerical Rating Scale (WP-NRS) daily over 16 weeks and every 2 weeks thereafter to week 24 in Heads Up. RESULTS: This analysis included 1683 patients in Measure Up 1 and 2 and 673 patients in Heads Up. Through 16 weeks in Measure Up 1 and 2, patients receiving upadacitinib spent 9.8-13.4 times as many days with an EASI 90 response and 7.0-10.3 times as many days with a WP-NRS 0/1 response versus placebo. In Heads Up, patients receiving upadacitinib spent 2.0 and 1.7 times as many days through 16 and 24 weeks, respectively, with an EASI 90 response versus dupilumab. Through 16 and 24 weeks, patients receiving upadacitinib spent 3.0 and 2.6 times as many days, respectively, with a WP-NRS 0/1 response versus dupilumab. CONCLUSIONS: Patients with moderate-to-severe AD spent more time with clear/almost clear skin and no/minimal itch with upadacitinib versus placebo or dupilumab. TRIAL REGISTRATION: ClinicalTrials.gov identifier, Measure Up 1 (NCT03569293), Measure Up 2 (NCT03607422), Heads Up (NCT03738397).

Lysophosphatidic Acid Receptors LPAR5 and LPAR2 Inversely Control Hydroxychloroquine-Evoked Itch and Scratching in Mice.

Lysophosphatidic acids (LPAs) evoke nociception and itch in mice and humans. In this study, we assessed the signaling paths. Hydroxychloroquine was injected intradermally to evoke itch in mice, which evoked an increase of LPAs in the skin and in the thalamus, suggesting that peripheral and central LPA receptors (LPARs) were involved in HCQ-evoked pruriception. To unravel the signaling paths, we assessed the localization of candidate genes and itching behavior in knockout models addressing LPAR5, LPAR2, autotaxin/ENPP2 and the lysophospholipid phosphatases, as well as the plasticity-related genes Prg1/LPPR4 and Prg2/LPPR3. LacZ reporter studies and RNAscope revealed LPAR5 in neurons of the dorsal root ganglia (DRGs) and in skin keratinocytes, LPAR2 in cortical and thalamic neurons, and Prg1 in neuronal structures of the dorsal horn, thalamus and SSC. HCQ-evoked scratching behavior was reduced in sensory neuron-specific Advillin-LPAR5-/- mice (peripheral) but increased in LPAR2-/- and Prg1-/- mice (central), and it was not affected by deficiency of glial autotaxin (GFAP-ENPP2-/-) or Prg2 (PRG2-/-). Heat and mechanical nociception were not affected by any of the genotypes. The behavior suggested that HCQ-mediated itch involves the activation of peripheral LPAR5, which was supported by reduced itch upon treatment with an LPAR5 antagonist and autotaxin inhibitor. Further, HCQ-evoked calcium fluxes were reduced in primary sensory neurons of Advillin-LPAR5-/- mice. The results suggest that LPA-mediated itch is primarily mediated via peripheral LPAR5, suggesting that a topical LPAR5 blocker might suppress "non-histaminergic" itch.

Symptom burden in chronic liver disease.

Chronic liver disease (CLD) is a significant contributor to global mortality. For people who are living with CLD, however, there is a substantial and often overlooked burden of physical and psychological symptoms that significantly affect health-related quality of life. CLD frequently presents with a multitude of interrelated and intricate symptoms, including fatigue, pruritus, muscle cramps, sexual dysfunction, and falls. Increasingly, there is interest in studying and developing interventional strategies to provide a more global approach to managing these complex patients. Moreover, in addition to established guidelines for the management of conventional complications, such as ascites and hepatic encephalopathy, there have been efforts in developing evidence-based guidance for the treatment of the more subjective yet still problematic elements. This review will address the management of these less "classical" but nonetheless important symptoms.

Mirogabalin inhibits scratching behavior of spontaneous model mouse of atopic dermatitis.

Introduction: Atopic dermatitis (AD) is one of the most prevalent intractable chronic itch diseases worldwide. In recent years, new molecular-targeted drugs have emerged, but side effects and economic challenges remain. Therefore, since it is important for AD patients to have a wider range of treatment options, it is important to explore new therapeutic agents. Gabapentinoids, gabapentin and pregabalin, have been shown to be effective for the clinical treatment of several chronic itch. Recently, mirogabalin (MGB) was developed as a novel gabapentinoid. MGB is a drug for neuropathic pain and has a margin of safety between its side effects and the analgesic effect for animal experiments. Herein, we showed that MGB exhibited an antipruritic effect in a mouse model of AD using NC/Nga mice. Methods and results: The oral administration of MGB (10 mg/kg) inhibited spontaneous scratching behavior in AD mice and its effect was dose dependently. Then, when MGB (10 mg/kg) was orally administrated to healthy mice, it did not affect motor function, including locomotor activity, wheel activity, and coordinated movement. Moreover, gabapentin (100 mg/kg) and pregabalin (30 mg/kg), inhibited spontaneous scratching behavior in AD mice and decreased motor function in healthy mice. Furthermore, intracisternal injection of MGB (10 µg/site) significantly suppressed spontaneous scratching behavior in AD mice. Discussion: In summary, our results suggest that MGB exerts an antipruritic effect via the spinal dorsal horn using NC/Nga mice. We hope that MGB is a candidate for a novel therapeutic agent for AD with relatively few side effects.

Dupilumab improves pruritus and skin lesions in patients with prurigo nodularis: Pooled results from 2 phase 3 trials (LIBERTY-PN PRIME and PRIME2).

Background: Phase 3 PRIME/PRIME2 trials independently demonstrated efficacy and an acceptable safety profile of dupilumab adults with moderate-to-severe prurigo nodularis. Objective: To obtain a more precise estimate of onset and magnitude of treatment effect using PRIME/PRIME2 pooled data. Methods: In PRIME/PRIME2, patients were randomized to dupilumab or placebo for 24 weeks. Pooled analysis assessed proportion of patients achieving clinically meaningful improvement in itch, clear/almost-clear skin, or both; at weeks 12 and 24; overall and by demographic subgroups and changes from baseline to week 24 in symptoms, signs, and quality of life. Results: Patients receiving dupilumab (n = 153) vs placebo (n = 158) experienced significant improvements in all tested endpoints. At week 24, 90 (58.8%) dupilumab-treated vs 30 (19.0%) placebo-treated patients achieved clinically meaningful improvement in itch, 71 (46.4%) vs 27 (17.1%) clear/almost clear skin, and 54 (35.3%) vs 14 (8.9%) achieved both (P < .0001 for all). Treatment benefits were independent of baseline demographics. Safety to week 36 was generally consistent with the known dupilumab safety profile. Limitations: On-treatment data limited to 24 weeks. Conclusions: Pooled analysis confirmed improvements reported in individual trials and revealed earlier effect onset in itch and skin pain. Dupilumab treatment showed benefits across demographics.

Histamine H4 receptor and TRPV1 mediate itch induced by cadaverine, a metabolite of the microbiome.

Cadaverine is an endogenous metabolite produced by the gut microbiome with various activity in physiological and pathological conditions. However, whether cadaverine regulates pain or itch remains unclear. In this study, we first found that cadaverine may bind to histamine 4 receptor (H4R) with higher docking energy score using molecular docking simulations, suggesting cadaverine may act as an endogenous ligand for H4R. We subsequently found intradermal injection of cadaverine into the nape or cheek of mice induces a dose-dependent scratching response in mice, which was suppressed by a selective H4R antagonist JNJ-7777120, transient receptor potential vanilloid 1 (TRPV1) antagonist capsazepine and PLC inhibitor U73122, but not H1R antagonist or TRPA1 antagonist or TRPV4 antagonist. Consistently, cadaverine-induced itch was abolished in Trpv1-/- but not Trpa1-/- mice. Pharmacological analysis indicated that mast cells and opioid receptors were also involved in cadaverine-induced itch in mice. scRNA-Seq data analysis showed that H4R and TRPV1 are mainly co-expressed on NP2, NP3 and PEP1 DRG neurons. Calcium imaging analysis showed that cadaverine perfusion enhanced calcium influx in the dissociated dorsal root ganglion (DRG) neurons, which was suppressed by JNJ-7777120 and capsazepine, as well as in the DRG neurons from Trpv1-/- mice. Patch-clamp recordings found that cadaverine perfusion significantly increased the excitability of small diameter DRG neurons, and JNJ-7777120 abolished this effect, indicating involvement of H4R. Together, these results provide evidences that cadaverine is a novel endogenous pruritogens, which activates H4R/TRPV1 signaling pathways in the primary sensory neurons.

Discovery of the first selective, small-molecule GFRα2/3 inhibitors through DNA-encoded library technology.

Studies have shown that disrupting the formation of the ligand-RET-GFRα complex could be an effective way of treating pain and itch. Compared to traditional high-throughput screens, DNA encoded libraries (DELs) have distinguished themselves as a powerful technology for hit identification in recent years. The present work demonstrates the use of DEL technology identifying compound 16 as the first GFRa2/GFRa3 small molecule inhibitor (0.1/0.2 µM respectively) selective over RET. This molecule represents an opportunity to advance the development of small-molecule inhibitors targeting the GFRα-RET interface for the treatment of pain and itch.

Stable Response and Sustained Improvement of Itch and Sleep Symptoms in Patients with Atopic Dermatitis Treated with Lebrikizumab over 52 Weeks.

BACKGROUND: Lebrikizumab demonstrated significant improvement versus placebo for measures of skin clearance and patient-reported outcomes at weeks 16 and 52 in patients with moderate-to-severe atopic dermatitis (AD). We report the sustained impact of lebrikizumab monotherapy, over 52 weeks and between visits, on the frequency of itch and sleep loss symptoms, as assessed by Patient-Oriented Eczema Measure (POEM), in patients with moderate-to-severe AD. METHODS: In ADvocate1 and ADvocate2, Week-16 lebrikizumab responders (EASI75 or IGA 0/1 with ≥ 2-point improvement and without rescue medication) were randomized to lebrikizumab every 2 weeks (Q2W), every 4 weeks (Q4W), or placebo for 36 weeks. This pooled analysis reports improvement from Week 16 to 52 in patients achieving POEM response 0 (no days) or 1 (1-2 days) for Items 1 (itch) and 2 (sleep disturbance) for the lebrikizumab Q2W and Q4W treatment arms. Observed (excluding data collected after treatment discontinuation, rescue medication use, or patient transfer to escape arm) results were reported. RESULTS: At Week 16, for lebrikizumab Q2W and Q4W, 35.9% (n = 37/103) and 39.3% (n = 42/107) of patients responded 0 or 1 to Item 1 of POEM (Itch) and 12.6% (n = 13/103) and 12.1% (n = 13/107) responded 0. A total of 66.0% (n = 68/103) and 72.6% (n = 77/106) of patients responded 0 or 1 to Item 2 of POEM (Sleep) and 37.9% (n = 39/103) and 44.3% (n = 47/106) responded 0, respectively. By Week 52, for lebrikizumab Q2W and Q4W, 44.6% (n = 29/65) and 48.0% (n = 36/75) responded 0 or 1 to Item 1 of POEM (Itch), and 21.5% (n = 14/65) and 18.7% (n = 14/75) of patients responded 0. A total of 83.1% (n = 54/65) and 78.4% (n = 58/74) responded 0 or 1 to Item 2 of POEM (Sleep), and 67.7% (n = 44/65) and 59.5% (n = 44/74) responded 0, respectively. CONCLUSION: Weekly POEM responses for itch and sleep disturbance remained stable between doses and visits, and continued to improve from Week 16 through 52, in lebrikizumab-treated patients, demonstrating consistent improvement over time for key AD symptoms. TRIAL REGISTRATION NUMBERS: ADvocate1 (NCT04146363) and ADvocate2 (NCT04178967).