Relationship between the Degrees of Itch and Serum Lipocalin-2 Levels in Patients with Psoriasis

Periostin C-Terminal Is Intrinsically Disordered and Interacts with 143 Proteins in an In Vitro Epidermal Model of Atopic Dermatitis

Human periostin is a 78-91 kDa matricellular protein implicated in extracellular matrix remodeling, tumor development, metastasis, and inflammatory diseases like atopic dermatitis, psoriasis, and asthma. The protein consists of six domains, including an N-terminal Cys-rich CROPT domain, four fasciclin-1 domains, and a C-terminal domain. The exons encoding the C-terminal domain may be alternatively spliced by shuffling four exons, generating ten variants of unknown function. Here, we investigate the structure and interactome of the full-length variant of the C-terminal domain with no exons spliced out. The structural analysis showed that the C-terminal domain lacked a tertiary structure and was intrinsically disordered. In addition, we show that the motif responsible for heparin-binding is in the conserved very C-terminal part of periostin. Pull-down confirmed three known interaction partners and identified an additional 140 proteins, among which nine previously have been implicated in atopic dermatitis. Based on our findings, we suggest that the C-terminal domain of periostin facilitates interactions between connective tissue components in concert with the four fasciclin domains.

Serum and Tissue Lipocalin-2 Expression in Chronic Kidney Disease Pruritic Patients

BACKGROUND

Uremic pruritus is an irritating symptom for patients with end-stage kidney disease. Lipocalin-2 (LCN2) has relevant importance in several biological cellular processes and immunity. It is also a major player in the progression of many disorders, such as renal injury.

AIM

To evaluate LCN2 expression in chronic kidney disease (CKD) pruritic patients in serum together with immunohistochemical expression in skin samples and further correlation of their results with the studied clinicopathologic parameters.

MATERIALS AND METHODS

Serum level of LCN2 (assessed by enzyme-linked immunosorbent assay) and skin immunohistochemical expression were investigated in 25 CKD patients and 25 healthy controls. Ten patients were subjected to narrowband ultraviolet B phototherapy for 12 weeks then re-evaluated for serum and tissue LCN2 after therapy.

RESULTS

LCN2 expression was increased significantly in both the epidermis and dermal adnexa in CKD patients over controls. Also, serum LCN2 level was higher in patients than in healthy subjects and was significantly associated with itching severity, grades of CKD, urea, and creatinine serum level. Tissue and serum levels of LCN2 were significantly diminished in CKD patients following narrowband therapy along with improvement of the severity of pruritus.

CONCLUSIONS

The increased serum and tissue LCN2 expression in CKD pruritic patients and its pronounced decrease, in addition to the improvement of pruritus after treatment, suggest a major pathogenic role of LCN2 in uremic pruritus.

Gene Ontology Analysis Highlights Biological Processes Influencing Responsiveness to Biological Therapy in Psoriasis

Psoriasis is a chronic, immune-mediated and inflammatory skin disease. Although various biological drugs are available for psoriasis treatment, some patients have poor responses or do not respond to treatment. The aim of the present study was to highlight the molecular mechanism of responsiveness to current biological drugs for psoriasis treatment. To this end, we reviewed previously published articles that reported genes associated with treatment response to biological drugs in psoriasis, and gene ontology analysis was subsequently performed using the Cytoscape platform. Herein, we revealed a statistically significant association between NF-kappaB signaling (p value = 3.37 × 10-9), regulation of granulocyte macrophage colony-stimulating factor production (p value = 6.20 × 10-6), glial cell proliferation (p value = 2.41 × 10-5) and treatment response in psoriatic patients. To the best of our knowledge, we are the first to directly associate glial cells with treatment response. Taken together, our study revealed gene ontology (GO) terms, some of which were previously shown to be implicated in the molecular pathway of psoriasis, as novel GO terms involved in responsiveness in psoriatic disease patients.

Human umbilical cord mesenchymal stem cell treatment alleviates symptoms in an atopic dermatitis-like mouse model

BACKGROUND

Atopic dermatitis (AD) is one of the most common immune and inflammatory skin disorders, leading to insufferable itching and skin abnormalities that seriously affect life quality of patients. There are still huge unmet needs for long-term and effective disease control, despite currently available therapies. Evidenced by some preclinical and clinical studies of AD treatment with stem cells, stem cell treatment could significantly and effectively ameliorate AD symptoms.

OBJECTIVES

To elucidate underlying mechanisms of how stem cells therapy alleviates AD-like symptoms.

METHODS

An AD-like mouse model was constructed and treated with mesenchymal stem cells (MSCs) subcutaneously or subcutaneously combined with intravenously. The differentially expressed genes were sorted out from RNA sequencing results of dorsal skin and blood.

RESULTS

Two injection routes of MSCs could alleviate AD-like symptoms and pathologic changes of the skin and immune organs. RNA sequencing of dorsal skin sections and blood provided gene expression signatures for amelioration of skin defects, inflammatory and immune modulation by MSCs, as well as common AD molecular markers for the skin and blood, which may benefit for clinical diagnosis. IL-1β and its signaling pathway were specifically found to be associated with the development of AD-like dermatitis lesions. MSC treatment effectively inhibited the JAK-STAT pathway and receptors of IL-4, IL-13, IL-17, and IgE.

CONCLUSIONS

MSC therapy could regulate abnormal immune and inflammatory status in AD. Mechanistic exploration will contribute to the development of personalized AD treatment based on MSCs.

Inflammatory Skin Disease Causes Anxiety Symptoms Leading to an Irreversible Course

Intense itching significantly reduces the quality of life, and atopic dermatitis is associated with psychiatric conditions, such as anxiety and depression. Psoriasis, another inflammatory skin disease, is often complicated by psychiatric symptoms, including depression; however, the pathogenesis of these mediating factors is poorly understood. This study used a spontaneous dermatitis mouse model (KCASP1Tg) and evaluated the psychiatric symptoms. We also used Janus kinase (JAK) inhibitors to manage the behaviors. Gene expression analysis and RT-PCR of the cerebral cortex of KCASP1Tg and wild-type (WT) mice were performed to examine differences in mRNA expression. KCASP1Tg mice had lower activity, higher anxiety-like behavior, and abnormal behavior. The mRNA expression of S100a8 and Lipocalin 2 (Lcn2) in the brain regions was higher in KCASP1Tg mice. Furthermore, IL-1β stimulation increased Lcn2 mRNA expression in astrocyte cultures. KCASP1Tg mice had predominantly elevated plasma Lcn2 compared to WT mice, which improved with JAK inhibition, but behavioral abnormalities in KCASP1Tg mice did not improve, despite JAK inhibition. In summary, our data revealed that Lcn2 is closely associated with anxiety symptoms, but the anxiety and depression symptoms caused by chronic skin inflammation may be irreversible. This study demonstrated that active control of skin inflammation is essential for preventing anxiety.

Glial Cells and Itch: Possible Targets for Novel Antipruritic Therapies

Glial cells, which are the non-neuronal cells of the nervous system, play essential roles in brain development, homeostasis, and diseases. Glial cells have attracted attention because of their active involvement in many neurological disorders. In recent years, substantial progress has been made in our understanding of the roles of glial cells in the pathogenesis of itch. Mechanistically, central and peripheral glial cells modulate acute and chronic pruritus via different mechanisms. In this review, we present the current knowledge about the involvement of glial cells in the modulation of itch processing and the mechanism of glial cell activation under itch stimuli. Targeting glial cells may provide novel approaches for itch therapy.

Critical Players and Therapeutic Targets in Chronic Itch

Chronic itch is one of the most prominent clinical characteristics of diverse systematic diseases. It is a devastating sensation in pathological diseases. Despite its importance, there are no FDA-labelled drugs specifically geared toward chronic itch. The associated complex pathogenesis and diverse causes escalate chronic itch to being one of the top challenges in healthcare. Humanized antibodies against IL-13, IL-4, and IL-31 proved effective in treatment of itch-associated atopic dermatitis but remain to be validated in chronic itch. There are still no satisfactory anti-itch therapeutics available toward itch-related neuropeptides including GRP, BNP, SST, CGRP, and SP. The newly identified potential itch targets including OSM, NMB, glutamate, periostin, and Serpin E1 have opened new avenues for therapeutic development. Proof-of-principle studies have been successfully performed on antagonists against these proteins and their receptors in itch treatment in animal models. Their translational interventions in humans need to be evaluated. It is of great importance to summarize and compare the newly emerging knowledge on chronic itch and its pathways to promote the development of novel anti-itch therapeutics. The goal of this review is to analyze the different physiologies and pathophysiologies of itch mediators, whilst assessing their suitability as new targets and discussing future therapeutic development.

Impact of Chronic Inflammation in Psoriasis on Bone Metabolism

Psoriasis is a chronic inflammatory disease of the skin and joints associated with several comorbidities such as arthritis, diabetes mellitus and metabolic syndrome, including obesity, hypertension and dyslipidaemia, Crohn's disease, uveitis and psychiatric and psychological diseases. Psoriasis has been described as an independent risk factor for cardiovascular diseases and thus patients with psoriasis should be monitored for the development of cardiovascular disease or metabolic syndrome. However, there is mounting evidence that psoriasis also affects the development of osteoporosis, an important metabolic disease with enormous clinical and socioeconomic impact. At present, there are still controversial opinions about the role of psoriasis in osteoporosis. A more in depth analysis of this phenomenon is of great importance for affected patients since, until now, bone metabolism is not routinely examined in psoriatic patients, which might have important long-term consequences for patients and the health system. In the present review, we summarize current knowledge on the impact of psoriatic inflammation on bone metabolism and osteoporosis.

Lipocalin-2 and insulin as new biomarkers of alopecia areata

Lipocalin-2 and visfatin are proinflammatory adipokines involved in the regulation of glucose homeostasis. Their role has been described in numerous inflammatory skin diseases such as atopic dermatitis and psoriasis. Recently, an increased prevalence of metabolic abnormalities has been reported in patients with alopecia areata. The aim of the study is to determine the serum levels of lipocalin-2 and visfatin in patients with alopecia areata in comparison with healthy controls. Moreover, the serum levels of total cholesterol, low-density lipoprotein cholesterol (LDL-cholesterol), high-density lipoprotein cholesterol (HDL-cholesterol), triglycerides, fasting glucose, insulin, c-peptide, and homeostasis model assessment for insulin resistance (HOMA-IR) were evaluated. Fifty-two patients with alopecia areata and 17 control subjects were enrolled in the study. The serum levels of lipocalin-2 [mean ± standard deviation, SD: 224.55 ± 53.58 ng/ml vs. 188.64 ± 44.75, p = 0.01], insulin [median (interquartile range, IQR): 6.85 (4.7–9.8) μIU/ml vs. 4.5 (3.5–6.6), p<0.05], c-peptide [median (IQR): 1.63 (1.23–2.36) ng/ml vs. 1.37 (1.1–1.58), p<0.05)], and HOMA-IR [median (IQR): 1.44 (0.98–2.15) vs. 0.92 (0.79–1.44), p<0.05) were significantly higher in patients with alopecia areata compared to the controls. The serum concentration of insulin and HOMA-IR correlated with the number of hair loss episodes (r = 0.300, p<0.05 and r = 0.322, p<0.05, respectively). Moreover, a positive correlation occurred between insulin, HOMA-IR, c-peptide and BMI (r = 0.436, p <0.05; r = 0.384, p<0.05 and r = 0.450, p<0.05, respectively). In conclusion, lipocalin-2 and insulin may serve as biomarkers for alopecia areata. Further studies are needed to evaluate the role of insulin as a prognostic factor in alopecia areata.

Lipocalin 2 Participates in the Epidermal Differentiation and Inflammatory Processes of Psoriasis

As a multifunctional cytokine, lipocalin 2 is weakly expressed in skin and serum under normal conditions. However, it is over-expressed by neutrophils and keratinocytes in the skin lesions and sera in several skin diseases. Recent studies demonstrated that lipocalin 2 participates in the pathogenesis of psoriasis by exerting versatile effects on skin resident cells and infiltrating immune cells. Lipocalin 2 inhibits the synthesis of keratin, involucrin, and loricrin in keratinocytes, leading to epidermal parakeratosis via the Tcf7l1-lipocalin 2 signaling axis. It also recruits inflammatory cells such as T cells and neutrophils into skin lesions via the IL-23/IL17, p38-MAPK, and ERK-1/2 signaling pathways. Additionally, lipocalin 2 and other cytokines such as IL-17 have the synergetic effects on skin cells. The neutralization of lipocalin 2 or relevant cytokines can alleviate psoriasis, verifying that lipocalin 2 is an effective interfering target for psoriasis. In this review, we summarize the roles of lipocalin 2 in the processes of psoriatic inflammation and the promising therapeutic strategies based on lipocalin 2-related molecules.

Lipocalin 2 Mediates Skin Inflammation in Psoriasis via the SREBP2-NLRC4 Axis

Lipocalins are a family of secreted adipokines that regulate cell lipid metabolism and immune responses. Although we have previously revealed that lipocalin 2 (LCN2) modulates neutrophil activation in psoriasis, the other roles of LCN2 in psoriatic local inflammation have remained elusive. Here, we found that 24p3R, the well-known specific receptor of LCN2, was highly expressed in the lesional epidermis of psoriasis patients. Silencing 24p3R alleviated hyperkeratosis, inflammatory cell infiltration, and overexpression of inflammatory mediators in an imiquimod (IMQ)-induced psoriasis-like mouse model. In vitro, LCN2 enhanced the expression of pro-inflammatory factors in primary keratinocytes, such as interleukin (IL)-1β, IL-23, C-X-C motif chemokine ligand (CXCL)1, and CXCL10, which was paralleled by enforced cholesterol biosynthetic signaling. Importantly, taking in vivo and in vitro approaches, we discovered the sterol response element binding factor 2 (SREBP2), a vital transcriptional factor in cholesterol synthesis pathway, as the critical mediator of LCN2-induced keratinocyte activation, which bond to the promoter region of NLR-family CARD-containing protein 4 (NLRC4). Suppressing SREBP2 in mice attenuated NLRC4 signaling and psoriasis-like dermatitis. Taken together, this study identifies the critical role of LCN2-SREBP2-NLRC4 axis in the pathogenesis of psoriasis, and proposes 24p3R or SREBP2 as potential therapeutic target for psoriasis.

Skewed inflammation is associated with aberrant interleukin-37 signaling pathway in atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is a severe global burden on physical, physiological, and mental health. The role of IL-37, a fundamental inhibitor of immunity, in AD was herein explored.

METHOD

Serum levels of IL-37 and T helper (Th) 2-related inflammatory mediators were quantified in subjects with or without AD. The expression of IL-37 receptors was determined by flow cytometry. Proteomics was employed to explore the serum protein profile and novel biomarkers. In vitro cell model, 3D-keratinocytes mimicking skin model, and the serum of subjects with or without AD were investigated to verify the proteomic results.

RESULTS

AD patients were found to present with higher levels of total and specific IgE as well as Th2 inflammatory mediators compared with healthy controls (HC). IL-37 level and its receptor IL18Rɑ expression in AD patients were significantly decreased, together with increased population of eosinophils, indicating that the signaling of IL37/IL18Rɑ was dampened. In addition, proteomic analysis revealed a significantly differential protein profile of AD patients compared with HC. IL-37 showed the strongest negative correlation with involucrin, a keratinizing epithelia protein. IL-37 was verified to suppress induced involucrin expression in in vitro skin cell models. AD patients show a significantly higher serum concentration of involucrin compared with HC. Together, our results demonstrated that IL-37 plays a regulatory role in AD. Its deficiency may lead to the aberrant involucrin expression in AD.

CONCLUSIONS

The dysregulation of serum protein and skin disruption in AD is related to the insufficiency of IL-37 and its attenuated anti-inflammatory signaling.

Characteristics of Pruritus in Various Clinical Variants of Psoriasis: Results of the Multinational, Multicenter, Cross-Sectional Study

Psoriasis is a chronic, inflammatory skin disease present in about 3% of the world’s population. The clinical symptoms manifest diversely, therefore one can distinguish several subtypes of psoriasis. The majority of patients with psoriasis experience pruritus, which is an unpleasant sensation that decreases patients’ quality of life. The knowledge on pruritus in different subtypes of psoriasis is limited. We have performed a cross-sectional, prospective, and multicenter study to evaluate the relationship between clinical subtypes of psoriasis (large-plaque, nummular, guttate, palmoplantar, inverse, erythrodermic, palmoplantar pustular, generalized pustular psoriasis, and psoriasis of the scalp) and the prevalence, intensity, and clinical manifestation of itch. We introduced a questionnaire assessing various aspects of pruritus to a total of 254 patients. Out of these, 42 were excluded. Pruritus was present in 92.9% of the remaining patients and its prevalence did not depend on the clinical subtype. A correlation between the severity of psoriasis and the intensity of itch was explicitly noticeable in palmoplantar pustular psoriasis and scalp psoriasis (p < 0.05). The itch sensation was individual and differed among subtypes of psoriasis. In conclusion, pruritus is a frequent phenomenon, and its presentation is different in various subtypes of psoriasis.

Network analysis of potential risk genes for psoriasis

Background

Psoriasis is a complex chronic inflammatory skin disease. The aim of this study was to analyze potential risk genes and molecular mechanisms associated with psoriasis.

Methods

GSE54456, GSE114286, and GSE121212 were collected from gene expression omnibus (GEO) database. Differentially expressed genes (DEGs) between psoriasis and controls were screened respectively in three datasets and common DEGs were obtained. The biological role of common DEGs were identified by enrichment analysis. Hub genes were identified using protein–protein interaction (PPI) networks and their risk for psoriasis was evaluated through logistic regression analysis. Moreover, differentially methylated positions (DMPs) between psoriasis and controls were obtained in the GSE115797 dataset. Methylation markers were identified after comparison with the common genes.

Results

A total of 118 common DEGs were identified, which were mainly involved in keratinocyte differentiation and IL-17 signaling pathway. Through PPI network, we identified top 10 degrees as hub genes. Among them, high expression of CXCL9 and SPRR1B may be risk factors for psoriasis. In addition, we selected 10 methylation-modified genes with the higher area under receiver operating characteristic curve (AUC) value as methylation markers. Nomogram showed that TGM6 and S100A9 may be associated with an increased risk of psoriasis.

Conclusion

This suggests that immune and inflammatory responses are active in keratinocytes of psoriatic skin. CXCL9, SPRR1B, TGM6 and S100A9 may be potential targets for the diagnosis and treatment of psoriasis.

DZ2002 alleviates psoriasis-like skin lesions via differentially regulating methylation of GATA3 and LCN2 promoters

Psoriasis is the most prevalent inflammatory skin disorders, affecting 1-3% of the worldwide population. We previously reported that topical application of methyl 4-(adenin-9-yl)-2-hydroxybutanoate (DZ2002), a reversible S-adenosyl-l-homocysteine hydrolase (SAHH) inhibitor, was a viable treatment in murine psoriatic skin inflammation. In current study, we further explored the mechanisms of DZ2002 on keratinocyte dysfunction and skin infiltration, the key pathogenic events in psoriasis. We conducted genome-wide DNA methylation analysis in skin tissue from imiquimod (IMQ)-induced psoriatic and normal mice, demonstrated that topical administration of DZ2002 directly rectified aberrant DNA methylation pattern in epidermis and dermis of psoriatic skin lesion. Especially, DZ2002 differentially regulated DNA methylation of GATA3 and LCN2 promoters, which maintained keratinocytes differentiation and reduced inflammatory infiltration in psoriatic skin respectively. In vitro studies in TNF-α/IFN-γ-elicited HaCaT manifested that DZ2002 treatment rectified compromised keratinocyte differentiation via GATA3 enhancement and abated chemokine expression by reducing LCN2 production under inflammatory stimulation. Chemotaxis assays conducted on dHL-60 cells confirmed that suppression of LCN2 expression by DZ2002 was accompanied by CXCR1 and CXCR2 downregulation, and contributed to the inhibition of CXCL8-driven neutrophils migration. In conclusion, therapeutic benefits of DZ2002 are achieved through differentially regulating DNA methylation of GATA3 and LCN2 promoters in psoriatic skin lesion, which efficiently interrupt the pathogenic interplay between keratinocytes and infiltrating immune cells, thus maintains epidermal keratinocytes differentiation and prevents dermal immune infiltration in psoriatic skin.

Molecular Aspects of Pruritus Pathogenesis in Psoriasis

Psoriasis is a chronic, systemic inflammatory disease with a genetic background that involves almost 3% of the general population worldwide. Approximately, 70–90% of patients with psoriasis suffer from pruritus, an unpleasant sensation that provokes a desire to scratch. Despite the enormous progress in understanding the mechanisms that cause psoriasis, the pathogenesis of psoriasis-related pruritus still remains unclear. In order to improve patients’ quality of life, development of more effective and safer antipruritic therapies is necessary. In turn to make it possible, better understanding of complexed and multifactorial pathogenesis of this symptom is needed. In this article we have systematized the current knowledge about pruritus origin in psoriasis.

Adipokines in the Skin and in Dermatological Diseases

Adipokines are the primary mediators of adipose tissue-induced and regulated systemic inflammatory diseases; however, recent findings revealed that serum levels of various adipokines correlate also with the onset and the severity of dermatological diseases. Importantly, further data confirmed that the skin serves not only as a target for adipokine signaling, but may serve as a source too. In this review, we aim to provide a complex overview on how adipokines may integrate into the (patho) physiological conditions of the skin by introducing the cell types, such as keratinocytes, fibroblasts, and sebocytes, which are known to produce adipokines as well as the signals that target them. Moreover, we discuss data from in vivo and in vitro murine and human studies as well as genetic data on how adipokines may contribute to various aspects of the homeostasis of the skin, e.g., melanogenesis, hair growth, or wound healing, just as to the pathogenesis of dermatological diseases such as psoriasis, atopic dermatitis, acne, rosacea, and melanoma.

Antimicrobial peptides: bridging innate and adaptive immunity in the pathogenesis of psoriasis

Antimicrobial peptides (AMPs) are small molecules produced by a myriad of cells and play important roles not only in protecting against infections and sustaining skin barrier homeostasis but also in contributing to immune dysregulation under pathological conditions. Recently, increasing evidence has indicated that AMPs, including cathelicidin (LL-37), human β-defensins, S100 proteins, lipocalin 2, and RNase 7, are highly expressed in psoriatic skin lesions. These peptides broadly regulate immunity by interacting with various immune cells and linking innate and adaptive immune responses during the progression of psoriasis. In this review, we summarize the recent findings regarding AMPs in the pathogenesis of psoriasis with a main focus on their immunomodulatory abilities.

Molecular and Cellular Mechanisms of Itch in Psoriasis

Itch (or pruritus) was not previously recognized as a serious symptom of psoriasis. However, approximately 60-90% of psoriatic patients with pruritus have stated that it deteriorates their quality of life. Since conventional antipruritic therapies, such as antihistamines, only exert limited effects, the establishment of a treatment option for itch in psoriasis is urgently needed. Although a definitive drug is not currently available, various itch mediators are known to be involved in pruritus in psoriasis. In this review, we describe the clinical features of pruritus in psoriasis, classify a wide range of itch mediators into categories, such as the nervous, immune, endocrine, and vascular systems, and discuss the mechanisms by which these mediators induce or aggravate itch in the pathophysiology of psoriasis.

Adipokines as Biomarkers of Atopic Dermatitis in Adults

Atopic dermatitis (AD) is characterized by chronic, relapsing, pruritic skin inflammation and does not have a well-understood pathogenesis. In this study, we addressed the contribution of adipokines to AD eczema based on the assessment of blood levels of adiponectin, resistin, leptin, lipocalin-2, and vaspin in adult non-obese patients suffering from chronic extrinsic childhood-onset AD. We investigated 49 AD patients with a median age of 37 years. The control group consisted of 30 age-matched healthy subjects. Adipokines were assessed in the serum by ELISA assays and the severity of AD with the SCORing Atopic Dermatitis (SCORAD) index. We found that adiponectin and resistin decreased and leptin appreciably increased in AD patients when compared to those in healthy subjects. Further, the levels of adiponectin and resistin were inversely related to the intensity of eczema. In conclusion, apart from the formerly investigated role of leptin in AD, this study points to adiponectin and resistin as the potential candidate adipokine biomarkers involved in shaping eczema intensity and severity, which may help predict disease exacerbations and enable the development of effective targeted therapeutic interventions.

Neutrophils in Psoriasis

Neutrophils are the most abundant innate immune cells. The pathogenic roles of neutrophils are related to chronic inflammation and autoimmune diseases. Psoriasis is a chronic systemic inflammatory disease affecting ~2–3% of the world population. The abundant presence of neutrophils in the psoriatic skin lesions serves as a typical histopathologic hallmark of psoriasis. Recent reports indicated that oxidative stress, granular components, and neutrophil extracellular traps from psoriatic neutrophils are related to the initial and maintenance phases of psoriasis. This review provides an overview on the recent (up to 2019) advances in understanding the role of neutrophils in the pathophysiology of psoriasis, including the effects of respiratory burst, degranulation, and neutrophil extracellular trap formation on psoriatic immunity and the clinical relationships.

Association of Serum Lipocalin-2 Concentrations with Psoriasis and Psoriatic Arthritis: An Updated Meta-Analysis

Objectives

The purpose of this study was to explore the association of serum lipocalin-2 concentrations with psoriasis and psoriatic arthritis (PsA).

Methods

A systematic search of studies on the association of serum lipocalin-2 concentrations with psoriasis/PsA was conducted in PubMed, Web of Science, Elsevier ScienceDirect, and Cochrane Library. Eventually, 8 eligible studies were included. The strength of association between serum lipocalin-2 concentrations and psoriasis/PsA was assessed by pooled standard mean difference (SMD) with its 95% confidence intervals (CIs).

Results

A total of 8 case-control studies, consisting of 349 psoriasis/PsA patients and 258 controls, were included in the meta-analysis. This meta-analysis showed significant association between serum lipocalin-2 concentrations and psoriasis/PsA in overall population (SMD: 0.757, 95%CI = 0.588-0.926, and P _H = 0.114; P _H is the P value for the heterogeneity test). Similar results were found in subgroup analysis by ethnicity.

Conclusions

Serum lipocalin-2 concentrations are higher in psoriasis/PsA patients than controls. However, more large-scale studies are warranted to explore the association between serum lipocalin-2 and the pathogenetic mechanisms of psoriasis/PsA.