Downregulation of Caveolae-Associated Proteins in Psoriasis: A Case Series Study.

We have previously identified that a structural membrane protein Caveolin-1 (Cav1) is involved in the regulation of aberrant keratinocyte proliferation and differentiation. The aim of this study was to elucidate the role of Cav1, Caveolin-2 (Cav2), and Cavin-1 in the pathogenesis of psoriasis vulgaris and between psoriasis subtypes. We utilized human biopsies from validated cases of psoriasis vulgaris (n = 21) at the University of Miami Hospital and compared the expression of Cav1, Cav2, and Cavin-1 by immunohistochemistry staining with that in normal healthy age-/sex-/location-matched skin (n = 15) and chronic spongiotic dermatitis skin samples (as control inflammatory skin condition) and quantified using QuPath. Distinct subtypes of psoriasis included guttate, inverse, nail, plaque, palmoplantar, and pustular. All biopsy samples exhibited a trend toward downregulation of Cav1, with nail, plaque, and palmoplantar psoriasis exhibiting the most pronounced effects. Only nail and pustular psoriasis samples exhibited significant downregulation of Cav2 and Cavin-1, suggesting Cav1 to be the main caveolar contributor to the pathogenesis of psoriasis. Together, these data support caveolae as pathophysiological targets in nail and pustular psoriasis, whereas Cav1 seems to be a general biomarker of multiple subtypes of psoriasis.

Increased Systemic Levels of Centrally Acting B-Type Natriuretic Peptide Are Associated with Chronic Itch of Different Types.

B-type natriuretic peptide (BNP) is an itch-selective neuropeptide that was shown to play a role in both histaminergic and nonhistaminergic itch in mice. It was also shown that elevated serum BNP is linked to increased pruritus in nondiabetic hemodialysis patients. This study examined plasma BNP levels of 77 patients and N-terminal pro-BNP levels of 33 patients with differing types of chronic itch to see whether BNP and N-terminal pro-BNP levels can correlate with itch severity. Plasma BNP and N-terminal pro-BNP levels of all patients with itch correlated with itch numerical rating scale and in particular for patients with chronic pruritus of unknown origin. On the basis of this clinical observation, this study further showed that increasing pathophysiological levels of BNP in mice by intravenous or osmotic pump induced significant scratching. In addition, pharmacological and ablation strategies determined that BNP acts centrally by activating the natriuretic peptide receptor A in the dorsal horn of the spinal cord. These data support that BNP and N-terminal pro-BNP levels are associated with chronic itch and may be used in clinical setting.

Prolonged Antipruritic Effect of Botulinum Toxin Type A on Cowhage-induced Itch: A Randomized, Single-blind, Placebo-controlled Trial.

Botulinum toxin type A (Botox) is thought to have antipruritic effects through inhibition of pruritic factors, including acetylcholine, substance P, and glutamate. The aim of this randomized, single-blind, placebo-controlled trial was to test the effect of botulinum toxin type A on cowhage, a non-histaminergic model for chronic itch. Botulinum toxin type A was injected into the arm of 35 healthy subjects, with a saline control injected into the contralateral arm. Thermal sensory parameters (warmth and heat thresholds and heat pain intensity) and itch intensity after cowhage application were examined on test areas. Botulinum toxin type A reduced itch intensity, overall perceived itch (area under the curve (AUC); percentage change from baseline), and peak itch intensity compared with the control at 1 week, 1 month, and 3 months. Botulinum toxin type A had no effect on thermal thresholds or heat pain intensity. In conclusion, botulinum toxin type A reduced cowhage itch for at least 3 months, which suggests that botulinum toxin type A is a potential long-lasting treatment for localized, non-histaminergic itch.

Neuroimmune Mediators of Pruritus in Hispanic Scalp Psoriatic Itch.

Scalp psoriatic itch is a common, bothersome, yet understudied, condition with numerous associated treatment challenges. The aim of this study was to enhance our understanding of the pathophysiology of scalp psoriatic itch. Immunohistochemical analysis of known neuroimmune mediators of pruritus was conducted using scalp biopsies from 27 Hispanic psoriatic patients. Patients were categorized into mild/moderate or severe itch groups according to their itch intensity rating of scalp itch. Protease activated receptor (PAR2), substance P, transient receptor potential (TRP)V3, TRPM8 and interleukin-23 expression all correlated  significantly with itch intensity. The pathophysiology of scalp psoriasis is largely non-histaminergic, mediated by PAR2, interleukin-23, transient receptor potential channels, and substance P.

IL-17 Expression in the Perifollicular Fibrosis in Biopsies From Lichen Planopilaris.

BACKGROUND: Lichen planopilaris (LPP) is a primary lymphocytic cicatricial alopecia for which therapy is often ineffective and there is no cure. OBJECTIVES: Looking for a new targetable molecule in the treatment of LPP, we sought to verify whether IL-17 expression is increased in scalp biopsies from patients with active scalp lesions of LPP. METHODS: Horizontal sections of hematoxylin and eosin-stained slides from 40 scalp biopsies of active LPP were retrospectively collected and stained with the monoclonal antibody against IL-17 (Abcam, Cambridge, MA; ab79056, dilution 1:100). Twenty biopsies from patients with chronic telogen effluvium served as controls because of their morphological resemblance to the normal scalp. Statistical analysis was performed using IBM SPSS Statistics for Windows (IBM Corporation, Armonk, NY). RESULTS: The main finding was the positive cytoplasmic expression of IL-17 in the perifollicular fibrosis of the affected follicles in LPP which was statistically significant compared with the controls ( P < 0.0001). The labeled cells were identified as fibroblasts based on their spindle shape and fascicular concentric arrangement in tight perifollicular distribution. Although most of the LPP specimens (n = 35; 87.5%) also revealed cytoplasmic IL-17 expression in the lichenoid inflammatory infiltrate, the results were not statistically significant ( P = 0.1351). CONCLUSION: Our immunohistochemistry results show that blocking the IL-17 inflammatory pathway may interfere with the progression of the perifollicular fibrosis and inflammation in LPP.

Antipruritic Effect of Topical Acetaminophen Gel in Histaminergic and Non-histaminergic Itch Provocation: A Double-blind, Vehicle-controlled Pilot Study.

There is a need for new topical antipruritics that are effective on many types of itch. This study examined the antipruritic efficacy of a new formulation of topical acetaminophen. In vitro skin permeability studies showed that 2.5% and 5% formulations are able to rapidly deliver an adequate amount of the drug into the skin. In a double-blind, vehicle-controlled, randomized study in 17 healthy volunteers, 1%, 2.5% and 5% acetaminophen gels and a vehicle gel were applied to the skin prior to histaminergic and non-histaminergic itch induction and assessment of thermal pain thresholds. The 2.5% and 5% gel formulations significantly reduced the itch intensity time course and the area under the curve for both histamine and cowhage itch. No effect was noted on heat pain thresholds and no adverse effects were observed. These results suggest that topical acetaminophen would be a safe and effective over-the-counter medication for itch.

Itch intensity in prurigo nodularis is closely related to dermal interleukin-31, oncostatin M, IL-31 receptor alpha and oncostatin M receptor beta.

Prurigo nodularis (PN) is a chronic skin dermatosis with hyperkeratotic and intensely pruritic nodules. Managing PN-associated itch is difficult because its aetiology is still unknown. This study aimed to investigate the correlation between itch intensity in PN and the expression of a pruritogenic cytokine interleukin (IL)-31, its receptor complex components IL-31 receptor α (IL-31RA) and oncostatin M receptor ß (OSMRß), and oncostatin M (OSM), which is a ligand of OSMR ß, through immunofluorescence staining examination. Itch intensity in PN was closely correlated with the number of dermal IL-31(+) cells (Spearman's r = 0.551, p < 0.05), dermal IL-31RA(+) cells (r = 0.475, p < 0.05) and dermal OSM(+) cells (r = 0.505, p < 0.05). In addition, the number of dermal OSMRß (+) cells was increased in PN (t test, p < 0.05), despite not being correlated with itch intensity (Spearman's r = 0.375, p > 0.05). Major cellular sources of dermal IL-31 were T cells (27.0% of total IL-31-expressing cells) and macrophages (35.0%), while those of OSM were mainly T cells (49.8%) and mast cells (26.8%). IL-31RA-expressing dermal cells were mostly mast cells (49.3%) and macrophages (36.6%), and OSMRß was mainly expressed by macrophages (51.8%) in the dermis. These findings indicate that IL-31 (mainly from macrophages and T cells) and OSM (principally from T cells and mast cells) stimulate dermal cells expressing IL-31RA and OSMRß (e.g. macrophages), which may further promote itch and inflammation in PN. This complex dermal milieu of cell/cytokine/receptor network can be a therapeutic target for PN-associated itch.

Psychiatric Comorbidities in Non-psychogenic Chronic Itch, a US-based Study.

Research suggests that itch and psychiatric diseases are intimately related. In efforts to examine the prevalence of psychiatric diagnoses in patients with chronic itch not due to psychogenic causes, we conducted a retrospective chart review of 502 adult patients diagnosed with chronic itch in an outpatient dermatology clinic specializing in itch and assessed these patients for a co-existing psychiatric disease. Psychiatric disease was identified and recorded based on ICD-10 codes made at any point in time which were recorded in the patient's electronic medical chart, which includes all medical department visits at the University of Miami. Fifty-five out of 502 (10.9%) of patients were found to have a comorbid psychiatric diagnosis based on ICD-10 codes. The most common psychiatric diagnoses were anxiety disorders (45.5%), followed by major depressive disorder (36.4%). There was no significant association of any specific type of itch to a particular psychiatric disorder. No unique itch characteristics were noted in patients with underlying psychiatric diagnoses.

Pathophysiologic mechanisms of itch in bullous pemphigoid.

BACKGROUND: One of the hallmarks of bullous pemphigoid (BP) is moderate to severe chronic itch. Managing this is difficult because little is known about the mechanisms of itch in BP. OBJECTIVE: We sought to elucidate the pathophysiologic mechanisms of itch in BP. METHODS: The expression of itch mediators in lesions of 24 patients with BP and 6 healthy individuals were examined through immunofluorescence staining. Furthermore, the expression of itch mediators and itch severity was correlated. RESULTS: Itch severity was correlated with eosinophils, substance P, neurokinin 1R, interleukin (IL) 31 receptor A, oncostatin M receptor-ß, IL-13, periostin, and basophils. There was also a trend between itch severity and IL-31 expression. Most of the cells expressing IL-31 or neurokinin 1R were identified as eosinophils. Intraepidermal nerve fiber density was decreased. Other itch mediators, including mast cells, IL-4, thymic stromal lymphopoietin, transient receptor potential vanilloid 1 and ankyrin 1, and protease activated receptor 2 were not significantly correlated with itch severity. LIMITATIONS: The relatively small sample size, the examination of protein expression exclusively through immunofluorescent analysis, and lack of functional assays in patients are the limitations. CONCLUSIONS: Multiple factors are involved in BP-associated itch, including eosinophils, substance P, neurokinin 1R, IL-31, IL-31 receptor A, oncostatin M receptor-ß, IL-13, periostin, and basophils. They could be useful therapeutic targets.

Mechanisms of Itch in Stasis Dermatitis: Significant Role of IL-31 from Macrophages.

Stasis dermatitis (SD) is a common disease in the elderly population, with pruritus being one of the troublesome symptoms. However, there are few therapeutic modalities available for SD-associated itch because little is known about its pathophysiological mechanism. Therefore, we sought to investigate the mediators of itch in SD using an immunofluorescence study on patient lesions focusing on IL-31. Ex vivo stimulation studies using murine peritoneal macrophages were also used to elucidate the pathological mechanisms of the generation of IL-31. In SD lesions, dermal infiltrating IL-31(+) cells were increased in number compared with the healthy controls, and the majority of IL-31(+) cells were CD68(+) macrophages. The presence of itch in SD was significantly associated with the amount of CD68(+)/IL-31(+) macrophages and CD68(+)/CD163(+) M2 macrophages. The number of CD68(+)/IL-31(+) macrophages was correlated with the number of dermal C-C chemokine receptor type 4(+) T helper type 2 cells, IL-17(+) cells, basophils, substance P(+) cells, and dermal deposition of periostin and hemosiderin. Furthermore, murine peritoneal macrophages expressed an M2 marker arginase-1 and generated IL-31 when stimulated with a combination of substance P, periostin, and red blood cell lysate (representing hemosiderin). IL-31 from macrophages may play a role in itch in SD.