Angiogenic and inflammatory properties of psoriatic arthritis

Targeted siRNA Therapy for Psoriasis: Translating Preclinical Potential into Clinical Treatments

Psoriasis is a chronic inflammatory skin disease characterized by the excessive proliferation of keratinocytes and heightened immune activation. Targeting pathogenic genes through small interfering RNA (siRNA) therapy represents a promising strategy for the treatment of psoriasis. This mini-review provides a comprehensive summary of siRNA research targeting the pathogenesis of psoriasis, covering aspects such as keratinocyte function, inflammatory cell roles, preclinical animal studies, and siRNA delivery mechanisms. It details recent advancements in RNA interference that modulate key factors including keratinocyte proliferation (Fibroblast Growth Factor Receptor 2, FGFR2), apoptosis (Interferon Alpha Inducible Protein 6, G1P3), differentiation (Grainyhead Like Transcription Factor 2, GRHL2), and angiogenesis (Vascular Endothelial Growth Factor, VEGF); immune cell infiltration and inflammation (Tumor Necrosis Factor-Alpha, TNF-α; Interleukin-17, IL-17); and signaling pathways (JAK-STAT, Nuclear Factor Kappa B, NF-κB) that govern immunopathology. Despite significant advances in siRNA-targeted treatments for psoriasis, several challenges persist. Continued scientific developments promise the creation of more effective and safer siRNA medications, potentially enhancing the quality of life for psoriasis patients and revolutionizing treatments for other diseases. This article focuses on the most recent research advancements in targeting the pathogenesis of psoriasis with siRNA and explores its future therapeutic prospects.

Cytokine profile characterization of naïve patients with psoriasis and psoriatic arthritis: implications for a pathogenic disease continuum

Background

The idea of psoriatic disease continuum has been progressively prompted based on the advances of the knowledge about the pathogenic steps underpinning the occurrence of psoriasis (PSO) and psoriatic arthritis (PSA). To evaluate biomolecules (inflammatory cytokines, inflammatory chemokines, cell adhesion and cellular mediators) in naïve patients with PSO, PSA with PSO, and PSA sine PSO. To stratify the results considering the presence of psoriatic nail involvement, extensive skin disease and obesity evaluating all involved patients.

Methods

By multiplex technology, 20 serum biomolecules were assessed with the inclusion of pro-inflammatory cytokines (GM-CSF, IFN-γ, IL-1α, IL-1β, IL-6, IL-8, IL-12p70, IL-17A, IL-23, TNF), anti-inflammatory cytokines (IFN-α, IL-4, IL-10, IL-13), inflammatory chemokines (IP-10, MCP-1, MIP-1α, MIP-1β), cell adhesion and cellular mediators (ICAM-1, E-selectin, P-selectin). The assessment of possible statistical differences between the means of the three groups was performed by One-Way ANOVA. In addition, by non-parametric T-tests, we stratified the results according to selected clinical characteristics (psoriatic nail involvement, PASI ≥ 10, BMI ≥ 30).

Results

In 80 assessed naïve patients, patients with PSO showed significant increases of E-selectin (p=0.021) and IL-8 (0.041) than other groups. In patients with PSA with PSO, significant higher levels of ICAM-1 were observed (p=0.009) than other groups. We did not observe further differences comparing pro-inflammatory and anti-inflammatory cytokines, inflammatory chemokines, and cell adhesion and cellular mediators in patients with PSO, PSA with PSO, and PSA sine PSO. Patients with psoriatic onychopathy showed significant increased levels of ICAM-1 (p=0.010) and IP-10 (0.030) than others. In patients with PASI ≥ 10, significantly enhanced values of IL-8 (p=0.004), TNF (p=0.013), E-selectin (p=0.004), MIP-1α (p=0.003), and MIP-1β (p=0.039). In patients with BMI ≥ 30, significantly higher levels of E-selectin were pointed out (p=0.035) than others.

Conclusion

Our findings may suggest that a similar cytokine profile may characterize naïve patients with PSO, PSA with PSO, and PSA sine PSO, reinforcing the concept of psoriatic disease continuum. However, some differences may be also shown, underlying possible pathogenic differences and leading to the clinical heterogeneity of these patients.

<i>TLR9</i> gene expression in immune cells of patients with psoriasis

Background. Psoriasis (skin lesions and psoriatic arthritis PA) is a chronic inflammatory autoimmune disease that can be triggered by excessive activation of endosomal toll-like receptors (TLRs), mainly TLR9. Elevated TLR9 levels are observed in both PA and psoriasis. Therefore, studying the expression pattern of the TLR9 gene may help select therapies for patients with PA and psoriasis. Aim. To study the expression pattern of the TLR9 gene in blood mononuclear cells of PA and psoriasis patients without joint involvement for possible use in the transition to targeted therapy. Materials and methods. Mononuclear cells were isolated from the peripheral blood of 31 patients with psoriasis vulgaris without joint involvement, 45 patients with PA, and 20 healthy volunteers. TLR9 gene expression was analyzed by real-time polymerase chain reaction. Results. A comparison of expression levels in PA patients and healthy volunteers showed that the expression level of TLR9 in PA patients was 591 times higher than that in healthy volunteers. The expression level of TLR9 in psoriasis patients without joint involvement was also significantly (423-fold) higher than that in healthy subjects. Conclusion. TLR9 gene expression in mononuclear cells of psoriasis patients with severe skin lesions is similar to that in PA patients. High levels of TLR9 gene expression may be a marker of possible joint involvement in patients with psoriasis and indicate the need to reconsider the therapeutic approach to a particular patient.

Investigating the Molecular Mechanism of Qianghuo Shengshi Decoction in the Treatment of Ankylosing Spondylitis Based on Network Pharmacology and Molecular Docking Analysis

Background: Qianghuo Shengshi decoction (QHSSD), a traditional Chinese medicine formula, is used to treat ankylosing spondylitis (AS) in China. The pharmacological mechanism of QHSSD for AS remains to be clarified. In this study, we investigated the molecular mechanisms of QHSSD in the treatment of AS using network pharmacology and molecular docking. Methods: To obtain the chemical components and potential targets of QHSSD, we used the Traditional Chinese Medicine Systematic Pharmacology Database and Analysis Platform (TCMSP) and SwissTargetPrediction. AS potential targets were found in the GeneCards, OMIM, and DisGenets databases. A Venn diagram was used to screen QHSSD and AS common potential targets. The STRING website and Cytoscape software were used to create and analyze protein–protein interactions and component–target networks. The DAVID database was used for the gene ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. Molecular docking was used to visualize drug–target interactions. Results: The component–target network consisted of 119 chemical components and 193 potential targets. QHSSD was implicated in various biological processes, such as inflammation and angiogenesis, and mediated multiple signaling pathways, such as the MAPK signaling pathway. Molecular docking revealed good binding ability between medicarpin, notoptol, vitetrifolin E, and cnidilin and EGFR, TNF-α, ALB, and VEGFA. Conclusions: The chemical compositions, potential targets, and pathways involved in the QHSSD treatment of AS were successfully predicted in this study. This study provides a solid foundation for the selection of drugs to treat AS.

Vascular Endothelial Growth Factor Biology and Its Potential as a Therapeutic Target in Rheumatic Diseases

Rheumatic diseases constitute a diversified group of diseases distinguished by arthritis and often involve other organs. The affected individual has low quality of life, productivity even life-threatening in some severe conditions. Moreover, they impose significant economic and social burdens. In recent years, the patient outcome has been improved significantly due to clearer comprehension of the pathology of rheumatic diseases and the effectiveness of "treat to target" therapies. However, the high cost and the adverse effects are the concerns and full remissions are not often observed. One of the main processes that contributes to the pathogenesis of rheumatic diseases is angiogenesis. Vascular endothelial growth factor (VEGF), a central mediator that regulates angiogenesis, has different isoforms and functions in various physiological processes. Increasing evidence suggests an association between the VEGF system and rheumatic diseases. Anti-VEGF and VEGF receptor (VEGFR) therapies have been used to treat several cancers and eye diseases. This review summarizes the current understanding of VEGF biology and its role in the context of rheumatic diseases, the contribution of VEGF bioavailability in the pathogenesis of rheumatic diseases, and the potential implications of therapeutic approaches targeting VEGF for these diseases.

The Molecular Pathophysiology of Psoriatic Arthritis-The Complex Interplay Between Genetic Predisposition, Epigenetics Factors, and the Microbiome

Psoriasis is a symmetric autoimmune/inflammatory disease that primarily affects the skin. In a significant proportion of cases, it is accompanied by arthritis that can affect any joint, the spine, and/or include enthesitis. Psoriasis and psoriatic arthritis are multifactor disorders characterized by aberrant immune responses in genetically susceptible individuals in the presence of additional (environmental) factors, including changes in microbiota and/or epigenetic marks. Epigenetic changes can be heritable or acquired (e.g., through changes in diet/microbiota or as a response to therapeutics) and, together with genetic factors, contribute to disease expression. In psoriasis, epigenetic alterations are mainly related to cell proliferation, cytokine signaling and microbial tolerance. Understanding the complex interplay between heritable and acquired pathomechanistic factors contributing to the development and maintenance of psoriasis is crucial for the identification and validation of diagnostic and predictive biomarkers, and the introduction of individualized effective and tolerable new treatments. This review summarizes the current understanding of immune activation, genetic, and environmental factors that contribute to the pathogenesis of psoriatic arthritis. Particular focus is on the interactions between these factors to propose a multifactorial disease model.

Psoriatic mesenchymal stem cells stimulate the angiogenesis of human umbilical vein endothelial cells in vitro

OBJECTIVE

To investigate the regulation of psoriatic dermal mesenchymal stem cells (p-DMSCs) in the expression of vascular growth factor (VEGF), and migration and angiogenesis of human umbilical vein endothelial cells (HUVECs) in vitro.

METHODS

A co-culture model of HUVECs and dermal mesenchymal stem cells (DMSCs)was used in this study. After 7-day co-culture, changes in expression levels of VEGF mRNA and protein in HUVECs were assessed using RT-PCR and Western Blotting, respectively. Migration and tubular formation of HUVECs were also assessed following co-culture of DMSCs and HUVECs.

RESULTS

In comparison to either HUVECs alone or co-culture of n-DMSCs and HUVECs, co-culture of HUVECs and p-DMSCs significantly increased expression levels of both VEGF mRNA (p < 0.01 vs. HUVECs alone) and protein in HUVECs (p < 0.001 vs. both HUVECs alone and HUVECs co-cultured with n-DMSCs). Moreover, p-DMSCs stimulated HUVEC migration and vascular formation (p < 0.05 vs. both HUVECs alone and co-culture of n-DMSCs and HUVECs).

CONCLUSION

Psoriatic DMSCs can upregulate VEGF expression, and stimulate migration and angiogenesis of HUVECs, suggesting a pathogenic role of p-DMSCs in psoriasis.

Periosteal Reaction Possibly Induced by Pazopanib: A Case Report and Literature Review

BACKGROUND

Although complications associated with pazopanib, a multitarget tyrosine kinase inhibitor, are known, periosteal reaction as a side effect has never been reported.

OBSERVATION

We present a case involving a male pediatric patient with desmoid tumors treated for 6 months with pazopanib who presented with pain and periosteal reaction in the ilium and scapula. Three months after termination of pazopanib therapy, the periosteal reaction in the scapula resolved and that in the ilium improved.

CONCLUSION

Children receiving pazopanib presenting with focal pain should be examined for the periosteal reaction; this knowledge may facilitate correct diagnosis of symptoms as a drug-associated finding.

The role of EMMPRIN/CD147 in regulating angiogenesis in patients with psoriatic arthritis

BACKGROUND

Angiogenesis plays a central role in the pathophysiology of rheumatic diseases. Patients with psoriatic arthritis (PsA) demonstrate increased vascularity over patients with rheumatoid arthritis (RA), with unknown mechanisms.

METHODS

We evaluated the serum levels of several pro- and anti-angiogenic factors in 62 PsA patients with active disease, 39 PsA patients in remission, 33 active RA patients, and 33 healthy controls (HC). Additionally, we used an in vitro co-culture system of fibroblast (HT1080) and monocytic-like (MM6) cell lines, to evaluate how their interactions affect the secretion of angiogenic factors and angiogenesis promoting abilities using scratch and tube formation assays.

RESULTS

PsA patients, regardless of disease activity, exhibited higher levels of EMMPRIN/CD147, IL-17, and TNF-α relative to RA patients or HC. Factors, such as IL-6, and the ratio between CD147 and thrombospondin-1, exhibited elevated levels in active PsA patients relative to PsA patients in remission. Secretion of CD147, VEGF, and MMP-9 was increased in vitro. CD147 neutralization with an antibody reduced these levels and the ability of endothelial cells to form tube-like structures or participate in wound healing.

CONCLUSIONS

CD147 plays a role in mediating angiogenesis in PsA, and the therapeutic possibilities of neutralizing it merit further investigation.

The Role of Ultrasound in Assessing Hand Joints and Tendons in Psoriatic Arthritis

Introduction: Psoriatic arthritis (PsA) is an inflammatory arthritis, usually involving peripheral joints, associated with cutaneous psoriasis, in the absence of rheumatoid factor and anti-citrullinated protein antibodies. Material and methods: The study included 28 patients diagnosed with psoriatic arthritis according to CASPAR criteria, presenting pain or swelling of the small joints of the hands and wrists, hospitalized in the Department of Rheumatology of the Emergency Clinical County Hospital of Craiova during 2016-2018. Results: In the 28 patients, a total of 840 joints were examined clinically and by ultrasound. From the clinical point of view, out of the total, 32 joints were swollen while 59 joints were tender. Dactylitis was evidenced in 20/280 examined digits upon physical examination. MUS revealed the presence of synovial proliferation in 108/840 sites (12.85%), with grade 1 synovitis in 4 joints (3.7%), grade 2 in 94 joints (87.03%) and grade 3 in 10 joints (9.25%). Out of 280 examined fingers 5.71% presented dactylitis, the third digit being the most commonly targeted. Grade 2 tenosynovitis was found in 40 of the examined tendons, whereas 8 tendons presented with grade 3 tenosynovitis. The most frequently involved were the flexor tendons of the digits (38 out of 40 tendons with inflammatory changes), followed by the extensor carpi ulnaris and flexor carpi radialis tendons. Conclusions: Ultrasound has proven its utility in assessing joint and tendon inflammation to a higher extent that clinically expected. Thus, MUS examination of hand joints may aid the clinician in diagnosing PsA, in evaluating the prognosis and the course of treatment.

Psoriatic Arthritis: What is Happening at the Joint?

Psoriatic arthritis (PsA) is a heterogeneous and inflammatory disease with diverse clinical manifestations, including psoriasis, nail psoriasis, peripheral joint disease, axial joint disease, enthesitis, and dactylitis. Typically, this varied clinical presentation complicates the clinician's ability to distinguish PsA from other forms of arthritis. In the synovium of individuals with PsA, upregulation of the genes WNT3A, BMPR2, and TGFBR1 results in bone erosion and new bone formation, a pattern unique to the disease. Additionally, genes associated with angiogenesis and vascularization such as VEGF and TGFB1 facilitate inflammation and joint damage. Gross pathogenesis of PsA is driven by proinflammatory cytokines, and key cytokines affecting joint structures include tumor necrosis factor-α, interleukin (IL)-6, IL-17A, IL-21, IL-22, and IL-23. Early diagnosis is critical for providing treatment that prevents irreversible disease progression and function loss. This narrative review discusses differentiation of PsA from other forms of arthritis. Additionally, we detail the role of cytokines at the joint in mediating PsA pathogenesis.Funding: Novartis Pharmaceuticals Corporation.

Impact of obesity on autoimmune arthritis and its cardiovascular complications

Obesity can instigate and sustain a systemic low-grade inflammatory environment that can amplify autoimmune disorders and their associated comorbidities. Metabolic changes and inflammatory factors produced by the adipose tissue have been reported to aggravate autoimmunity and predispose the patient to cardiovascular disease (CVD) and metabolic comorbidities. Rheumatoid arthritis (RA) and psoriatic arthritis (PsA) are autoimmune arthritic diseases, often linked with altered body mass index (BMI). Severe joint inflammation and bone destruction have a debilitating impact on the patient's life; there is also a staggering risk of cardiovascular morbidity and mortality. Furthermore, these patients are at risk of developing metabolic symptoms, including insulin resistance resulting in type 2 diabetes mellitus (T2DM). In addition, arthritis severity, progression and response to therapy can be markedly affected by the patient's BMI. Hence, a complex integrative pathogenesis interconnects autoimmunity with metabolic and cardiovascular disorders. This review aims to shed light on the network that connects obesity with RA, PsA, systemic lupus erythematosus and Sjӧgren's syndrome. We have focused on clarifying the mechanism by which obesity affects different cell types, inflammatory factors and traditional therapies in these autoimmune disorders. We conclude that to further optimize arthritis therapy and to prevent CVD, it is imperative to uncover the intricate relation between obesity and arthritis pathology.

Anti-angiogenic effects of biotechnological therapies in rheumatic diseases

Introduction

Angiogenesis plays a key role in the pathogenesis of numerous rheumatic diseases, such as rheumatoid arthritis, psoriatic arthritis, and vasculitides. Therefore, the inhibition of pathological angiogenesis may be considered a useful therapeutical approach in these rheumatic diseases.

Methods

This review article is based on a literature research about the role of biotechnological therapies in angiogenesis inhibition.

Results and conclusions

Several evidences have demonstrated a role for biotechnological therapies in angiogenesis inhibition. Nevertheless, further research and clinical trials are needed to better quantify the real impact of biotechnological therapies on pathological angiogenesis.

Angiogenesis Dysregulation in Psoriatic Arthritis: Molecular Mechanisms

There is evidence that psoriatic arthritis is closely linked to angiogenesis. Morphological changes described in blood vessels of psoriatic arthritis joints suggest the presence of a dysregulated angiogenesis resulting in the formation of immature vessels. Even if the reason of this inefficient angiogenesis is still unclear, an imbalance between angiogenic and antiangiogenic factors is probably responsible for inducing a dysregulated angiogenesis in psoriatic arthritis, which seems to be involved in its pathogenesis and clinical features. Nevertheless, among chronic arthritides, while angiogenesis in rheumatoid arthritis has been largely studied with a great amount of literature data, limited data on angiogenesis role in psoriatic arthritis are available. This review article is focused on current knowledge on the mechanisms responsible for dysregulated angiogenesis in psoriatic arthritis.

Ixekizumab, an interleukin-17A specific monoclonal antibody, for the treatment of biologic-naive patients with active psoriatic arthritis: results from the 24-week randomised, double-blind, placebo-controlled and active (adalimumab)-controlled period of the phase III trial SPIRIT-P1

OBJECTIVE

To assess the safety and efficacy of ixekizumab, a monoclonal antibody that inhibits interleukin-17A, in a double-blind phase III trial enrolling patients with active psoriatic arthritis (PsA).

METHODS

Patients naive to biologic therapy with active PsA were randomised to subcutaneous injections of placebo (N=106), adalimumab 40 mg once every 2 weeks (active reference; N=101), ixekizumab 80 mg once every 2 weeks (IXEQ2W) (N=103), or ixekizumab 80 mg once every 4 weeks (IXEQ4W) (N=107). Both ixekizumab regimens included a 160-mg starting dose. The primary objective was to assess the superiority of IXEQ2W or IXEQ4W versus placebo as measured by the proportion of patients achieving an American College of Rheumatology 20 (ACR20) response at week 24.

RESULTS

Significantly more patients treated with ixekizumab achieved an ACR20 response with IXEQ2W (62.1%) or IXEQ4W (57.9%) than placebo (30.2%) (p≤0.001; non-responder imputation method). Disease activity and functional disability were significantly improved with both ixekizumab doses versus placebo at weeks 12 and 24, and there was significantly less progression of structural damage at week 24 (p≤0.01). Clearance of plaque psoriasis was greater with ixekizumab than placebo (p≤0.001). Efficacy results with adalimumab, the active reference arm, showed significant improvements versus placebo. Treatment-emergent adverse events were more frequent with ixekizumab (65.7-66.4%) and adalimumab (64.4%) than placebo (47.2%) (p<0.05).

CONCLUSIONS

In biologic-naive patients with active PsA, ixekizumab treatment resulted in improvements in disease activity and physical function, as well as in the inhibition of structural damage progression. Overall, adverse events were more frequent in all active groups compared with placebo.

TRIAL REGISTRATION NUMBER

NCT01695239; EudraCT2011-002326-49; Results.

Influence of Extracellular RNAs, Released by Rheumatoid Arthritis Synovial Fibroblasts, on Their Adhesive and Invasive Properties

Extracellular RNA (exRNA) has been characterized as a molecular alarm signal upon cellular stress or tissue injury and to exert biological functions as a proinflammatory, prothrombotic, and vessel permeability-regulating factor. In this study, we investigated the contribution of exRNA and its antagonist RNase1 in a chronic inflammatory joint disease, rheumatoid arthritis (RA). Upon immunohistochemical inspection of RA, osteoarthritis (OA), and psoriatic arthritis synovium, exRNA was detectable only in the RA synovial lining layer, whereas extracellular DNA was detectable in various areas of synovial tissue. In vitro, exRNA (150-5000 nt) was released by RA synovial fibroblasts (RASF) under hypoxic conditions but not under normoxia or TNF-α treatment. RNase activity was increased in synovial fluid from RA and OA patients compared with psoriatic arthritis patients, whereas RNase activity of RASF and OASF cultures was not altered by hypoxia. Reduction of exRNA by RNase1 treatment decreased adhesion of RASF to cartilage, but it had no influence on their cell proliferation or adhesion to endothelial cells. In vivo, treatment with RNase1 reduced RASF invasion into coimplanted cartilage in the SCID mouse model of RA. We also analyzed the expression of neuropilins in synovial tissue and SF, as they may interact with vascular endothelial growth factor signaling and exRNA. The data support the concepts that the exRNA/RNase1 system participates in RA pathophysiology and that RASF are influenced by exRNA in a prodestructive manner.

The joint synovium: A critical determinant of articular cartilage fate in inflammatory joint diseases

The synovium constitutes the envelope of articular joints and is a critical provider of synovial fluid components and articular cartilage nutrients. Its inflammation is a predominant feature and cause of joint degeneration in diseases as diverse as rheumatoid, psoriatic, juvenile and idiopathic arthritis, and lupus, gout and lyme disease. These inflammatory joint diseases (IJDs) are due to a wide variety of genetic, epigenetic and environmental factors that trigger, promote, and perpetuate joint destabilization. In spite of this variety of causes, IJDs share main pathological features, namely inflammation of the joint synovium (synovitis) and progressive degeneration of articular cartilage. In addition to being a driving force behind the destruction of articular cartilage in IJD, synovitis is also increasingly being recognized as a significant contributor of articular cartilage degeneration in osteoarthritis, a disease primarily due to aging- or trauma-related wear and tear of cartilage surfaces. In view of this important role of the synovium in determining the fate of articular cartilage, this review focuses on its underlying mechanisms in the pathology of IJD. We address the roles of synovial fibroblasts, macrophages and endothelial cells in the maintenance of joint health and in the destruction of articular cartilage integrity during IJD. Molecular mechanisms that have been recently shown to govern the pathological activities of the resident synovial cells are highlighted. Finally, advantages and disadvantages of targeting these new molecular mechanisms for preventing cartilage degeneration due to chronic inflammation are also discussed.

Optimal management of dactylitis in patients with psoriatic arthritis

Psoriatic arthritis (PsA) is an inflammatory arthropathy associated with cutaneous psoriasis, which is currently classified as a seronegative spondyloarthropathy. The presence of cutaneous psoriasis is important for correct and early diagnosis of PsA, because the onset of cutaneous lesions usually precedes the appearance of joint manifestation. Thus, dermatologists are able to detect the condition at its inception. PsA has several unique characteristics such as enthesopathy, dactylitis, and abnormal bone remodeling. In particular, dactylitis occurs on the easily observed sites such as digits, and is thus a significant indicator of PsA. It is important to observe not only the fingers but also the toes, because dactylitis involves both digits of the hands and feet. Recently, new ideas regarding the involvement of the interleukin (IL)-23/Th17 axis have emerged, and the dramatic effects of targeting therapies have highlighted the physiological roles of key cytokines such as tumor necrosis factor-α, IL-17A, and IL-23 in psoriasis. As recent insights are shedding light on the pathogenesis of PsA, understanding of the pathogenesis of dactylitis and enthesitis are also progressing. In this article, current views on the optimal management of dactylitis are discussed.

Gene Expression Profiling in Peripheral Blood Cells and Synovial Membranes of Patients with Psoriatic Arthritis

Background

Psoriatic arthritis (PsA) is an inflammatory arthritis whose pathogenesis is poorly understood; it is characterized by bone erosions and new bone formation. The diagnosis of PsA is mainly clinical and diagnostic biomarkers are not yet available. The aim of this work was to clarify some aspects of the disease pathogenesis and to identify specific gene signatures in paired peripheral blood cells (PBC) and synovial biopsies of patients with PsA. Moreover, we tried to identify biomarkers that can be used in clinical practice.

Methods

PBC and synovial biopsies of 10 patients with PsA were used to study gene expression using Affymetrix arrays. The expression values were validated by Q-PCR, FACS analysis and by the detection of soluble mediators.

Results

Synovial biopsies of patients showed a modulation of approximately 200 genes when compared to the biopsies of healthy donors. Among the differentially expressed genes we observed the upregulation of Th17 related genes and of type I interferon (IFN) inducible genes. FACS analysis confirmed the Th17 polarization. Moreover, the synovial trascriptome shows gene clusters (bone remodeling, angiogenesis and inflammation) involved in the pathogenesis of PsA. Interestingly 90 genes are modulated in both compartments (PBC and synovium) suggesting that signature pathways in PBC mirror those of the inflamed synovium. Finally the osteoactivin gene was upregulared in both PBC and synovial biopsies and this finding was confirmed by the detection of high levels of osteoactivin in PsA sera but not in other inflammatory arthritides.

Conclusions

We describe the first analysis of the trancriptome in paired synovial tissue and PBC of patients with PsA. This study strengthens the hypothesis that PsA is of autoimmune origin since the coactivity of IFN and Th17 pathways is typical of autoimmunity. Finally these findings have allowed the identification of a possible disease biomarker, osteoactivin, easily detectable in PsA serum.

Metabolomics in psoriatic disease: pilot study reveals metabolite differences in psoriasis and psoriatic arthritis

Importance: While “omics” studies have advanced our understanding of inflammatory skin diseases, metabolomics is mostly an unexplored field in dermatology.

Objective: We sought to elucidate the pathogenesis of psoriatic diseases by determining the differences in metabolomic profiles among psoriasis patients with or without psoriatic arthritis and healthy controls.

Design: We employed a global metabolomics approach to compare circulating metabolites from patients with psoriasis, psoriasis and psoriatic arthritis, and healthy controls.

Setting: Study participants were recruited from the general community and from the Psoriasis Clinic at the University of California Davis in United States.

Participants: We examined metabolomic profiles using blood serum samples from 30 patients age and gender matched into three groups: 10 patients with psoriasis, 10 patients with psoriasis and psoriatic arthritis and 10 control participants.

Main outcome(s) and measures(s): Metabolite levels were measured calculating the mean peak intensities from gas chromatography time-of-flight mass spectrometry.

Results: Multivariate analyses of metabolomics profiles revealed altered serum metabolites among the study population. Compared to control patients, psoriasis patients had a higher level of alpha ketoglutaric acid (Pso: 288 ± 88; Control: 209 ± 69; p=0.03), a lower level of asparagine (Pso: 5460 ± 980; Control: 7260 ± 2100; p=0.02), and a lower level of glutamine (Pso: 86000 ± 20000; Control: 111000 ± 27000; p=0.02). Compared to control patients, patients with psoriasis and psoriatic arthritis had increased levels of glucuronic acid (Pso + PsA: 638 ± 250; Control: 347 ± 61; p=0.001). Compared to patients with psoriasis alone, patients with both psoriasis and psoriatic arthritis had a decreased level of alpha ketoglutaric acid (Pso + PsA: 186 ± 80; Pso: 288 ± 88; p=0.02) and an increased level of lignoceric acid (Pso + PsA: 442 ± 280; Pso: 214 ± 64; p=0.02).

Conclusions and relevance: The metabolite differences help elucidate the pathogenesis of psoriasis and psoriatic arthritis and they may provide insights for therapeutic development.

Serum YKL-40 in psoriasis with and without arthritis; correlation with disease activity and high-resolution power Doppler ultrasonographic joint findings

BACKGROUND

YKL-40 may be involved in angiogenesis in psoriasis and psoriatic arthritis (PsA). High-resolution power Doppler ultrasound (PDUS) can detect angiogenesis of synovium in PsA.

AIM

To assess serum YKL-40 in psoriasis patients with or without PsA, and to correlate its levels with disease activity and high-resolution PDUS findings.

METHODS

In this case-control study, 48 patients with psoriasis (26 of them also had PsA) and 30 controls were assessed by high-resolution PDUS, and assayed for serum levels of YKL-40 by ELISA. Patients were clinically assessed using Composite Psoriatic Disease Activity Index (CPDAI). Total joint score (TJS) was used to assess joint involvement in PsA.

RESULTS

A statistically significant elevation was found in YKL-40 levels in psoriatics with or without PsA compared with controls (P < 0.001), as well as in PsA (group II) compared to patients without arthritis (group I) (P = 0.002). CPDAI, synovial thickness score and colour Doppler ultrasound (CDUS) score were highly significantly higher in group II vs. group I (P < 0.001). In all patients, CPDAI, synovial thickness and CDUS score were positively correlated to each other, and each of them was positively correlated to serum YKL-40 levels (P < 0.05). In either group I or II, serum YKL-40 levels correlated positively with CPDAI (P < 0.05). In group II, TJS, synovial thickness and CDUS score were positively correlated to each other (P < 0.05).

CONCLUSIONS

Serum YKL-40 can be used as a new biological marker for angiogenesis and disease activity in psoriasis with or without PsA. High-resolution PDUS is a non-invasive tool for the evaluation of angiogenesis in PsA patients as well as for the detection of early synovial changes in psoriasis patients without arthritis.

Identification of psoriatic arthritis mediators in synovial fluid by quantitative mass spectrometry

Background

Synovial fluid (SF) is a dynamic reservoir for proteins originating from the synovial membrane, cartilage, and plasma, and may therefore reflect the pathophysiological conditions that give rise to arthritis. Our goal was to identify and quantify protein mediators of psoriatic arthritis (PsA) in SF.

Methods

Age and gender-matched pooled SF samples from 10 PsA and 10 controls [early osteoarthritis (OA)], were subjected to label-free quantitative proteomics using liquid chromatography coupled to mass spectrometry (LC-MS/MS), to identify differentially expressed proteins based on the ratios of the extracted ion current of each protein between the two groups. Pathway analysis and public database searches were conducted to ensure these proteins held relevance to PsA. Multiplexed selected reaction monitoring (SRM) assays were then utilized to confirm the elevated proteins in the discovery samples and in an independent set of samples from patients with PsA and controls.

Results

We determined that 137 proteins were differentially expressed between PsA and control SF, and 44 were upregulated. The pathways associated with these proteins were acute-phase response signalling, granulocyte adhesion and diapedesis, and production of nitric oxide and reactive oxygen species in macrophages. The expression of 12 proteins was subsequently quantified using SRM assays.

Conclusions

Our in-depth proteomic analysis of the PSA SF proteome identified 12 proteins which were significantly elevated in PsA SF compared to early OA SF. These proteins may be linked to the pathogenesis of PsA, as well serve as putative biomarkers and/or therapeutic targets for this disease.

Clinical and Contrast-Enhanced Ultrasound Echography Outcomes in Psoriatic Arthritis Patients after One Year of Continuous Therapy with Anti-TNF Drugs

Background. We wanted to verify retrospectively the proportion of patients with psoriatic arthritis who were in remission after 1 year of continuous therapy with either etanercept or adalimumab. Remission was defined as the absence of both clinical and contrast-enhanced ultrasound (CEUS) findings suggestive of joint inflammation. Patients and Methods. The data of twenty-five patients with psoriatic arthritis were available for the clinical and CEUS evaluations before and after 1 year of continuous therapy with etanercept or adalimumab. The count of swollen (ACR66), tender (ACR68), and active inflamed joints (AJC) was used to measure the severity of joint involvement. PASI was used to score the severity of psoriasis. HAQ, DLQI, VAS pain, and VAS itching were administered to each patient before starting therapy and every 3 months, up to 1 year. Results. Eight (32%) out of twenty-five patients were in remission after 1 year of therapy with etanercept or adalimumab. A significant reduction of all clinical variables analysed was seen during the course of therapy. Conclusion. Although a significant proportion of patients achieved remission of arthritis after 1 year of effective anti-TNF therapy, the majority of them continued to have either clinical or CEUS findings suggestive of persistence of joint inflammation.

The Th17 axis in psoriatic disease: pathogenetic and therapeutic implications

Psoriasis and psoriatic arthritis represent two paradigmatic conditions characterized by chronic inflammation and possibly autoimmunity, despite the absence of known serum autoantibodies. The two diseases, albeit strongly correlated from clinical, genetic, and epidemiogical standpoints, manifest significant differences in terms of etiology and pathogenetic mechanisms. Nonetheless, Th17 cells appear crucial to both diseases, and IL23 is the cytokine involved in determining the fate of naive CD4+ cells to differentiate into a pathogenic phenotype. This basic experimental observation led to a clear understanding of the immune dysfunction causing psoriasis and psoriatic arthritis but, more importantly, also led to new therapeutic approaches. In recent years, monoclonal antibodies directed to IL12/IL23 (ustekinumab) or IL17 (secukinumab, ixekizumab, brodalumab) are being investigated or have proven to be beneficial for patients with psoriatic disease, thus further supporting the view that Th17 cells play a pivotal role in disease onset and perpetuation. These most recent reports indeed represent significant developments that may allow overcoming the TNFα pathway as the major therapeutic target in chronic inflammation.

Putative effects of potentially anti-angiogenic drugs in rheumatic diseases

A role for angiogenesis has been described in several rheumatic diseases, including rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, systemic sclerosis, systemic lupus erythematosus, vasculitides, and osteoarthritis, leading to the possibility that angiogenesis inhibition may be an additional useful therapeutic arm. While the role of anti-angiogenic therapy in rheumatoid arthritis has received attention, it is conceivable that the inhibition of pathological angiogenesis may also be a useful therapeutical approach in other rheumatic diseases. Numerous compounds, such as, for example, various interleukins, antibodies directed against angiogenic factors, peptides, estrogen metabolites, disease-modifying anti-rheumatic drugs, have been found to have anti-angiogenic properties. However, additional research is needed to obtain a clear understanding of the pathogenic mechanism of angiogenesis and the potential applications of anti-angiogenic therapy in rheumatic diseases.