Pathogenesis Of Psoriatic Arthritis Research Articles

Clinical course of psoriatic arthritis treated with biologics delineated with ultrasonography.

Psoriatic arthritis (PsA) is a chronic, inflammatory articular disease regarded as a specific subtype of psoriasis. Long-term assessment for PsA using ultrasonography has not yet been investigated. The present study was conducted to delineate the changes in articular lesions after the initiation of biologics using ultrasonography, and to provide the evidence of the utility of ultrasonography in long-term follow-up of PsA patients. We retrospectively recruited 17 Japanese PsA patients treated with biologics who met the classification criteria for psoriatic arthritis. Ultrasonographic images were recorded using a high-frequency linear 18 MHz probe through Doppler- and B-modes. Before the treatment with biologics, all examined patients (100%) had enthesitis and extensor tendinitis, while only six patients (35.3%) had loss of the fibrillar pattern of the tendon (LFP). There were significant changes over time in the numerical rating scale score for pain, and in the degree of ultrasonographic findings, including enthesitis, extensor tendinitis, and LFP. Also, there were significant changes over time between these ultrasonographic findings. The study identified the improvement course for a specific PsA lesion after the initiation of biologics. The improvement courses in enthesitis, extensor tendinitis, and LFP were found to differ from each other. These results may contribute to deeper understanding of the pathogenesis of PsA.

Pathogenesis of psoriatic arthritis: new insights from a bone marrow perspective.

Psoriatic arthritis is an immune-mediated disease that primarily affects the skin and joints. It falls under the umbrella term of rheumatic diseases, which describes a group of closely related yet distinct disorders with many common underlying molecular pathways. Despite the distinct clinical manifestation of each disorder, the shared therapeutic strategies attest to the commonality of cellular and molecular underpinnings. Herein we provide a concise yet comprehensive overview of the interleukin (IL)-23/IL-17 axis and its involvement in mechanistic pathways leading to the pathogenesis of this dual skin and joint clinical manifestation which is characteristic of psoriatic arthritis and other rheumatic diseases. The interconnection between activated innate immune cells and adaptive immunity has transformed current thinking to include other organs such as the bone marrow as potential tissue of disease origin. A plethora of animal models and genetic studies converge on the critical role of IL-23/IL-17 axis, and highlight the importance of myeloid cell activation as common pathways between autoinflammatory and autoimmune diseases and chronic inflammation. These findings underscore the intricate immune mechanisms involved in inflammatory arthritis and highlight molecular mechanisms in disease pathogenesis. These insights pave the way for the development of novel diagnostic and therapeutic strategies, with a focus on translating these findings into improved clinical practice.

Effect of IL-7 and IL-7R blockade on cytokine production by peripheral blood t cells from patients with psoriatic arthritis

Psoriatic arthritis (PsA) is a chronic immune-mediated inflammatory joint disease, often associated with psoriasis. Interactions between immune cells, mainly T lymphocytes, and cells of the osteoarticular system are central in the pathogenesis of PsA. Th1, Th17 cytokines associated with the development of PsA contribute to an increase in the production of cytokines, chemokines, matrix metalloproteinases, adhesion molecules by immune cells, chondrocytes, fibroblasts, and induction of osteoclasts. That leads to the destruction of cartilage and bone tissue. Among the cytokines potentially involved in the pathogenesis of PsA, IL-7 is of particular interest. IL-7 is a T cell survival factor. However, it can promote the production of IFNγ and TNFα by T cells. IL-7 may indirectly promote osteoclast maturation and cartilage degradation. The aim was to investigate the effect of IL-7 and blockade of the α-chain of the IL-7 receptor (IL-7R) in vitro on the production of IL-5, IL-13, IL-2, IL-6, IL-9 IL-10, IFNγ, TNFα, IL-17A, IL-17F, IL-4, and IL-22 by T cells in norm and PsA.The study included 14 patients with PsA in the acute stage of the disease and 8 healthy individuals. To determine cytokines concentration, multiplex analysis was performed using flow cytometry.It was shown that IL-7 enhances the production of Th1, Th2, Th17, Th22, and Th9 cytokines in both patients with PsA and healthy individuals. The exception was IL-2 for both groups. Under the blockade of IL-7R with monoclonal antibodies, the level of IL-6 increases and production of IFNγ, TNFα, IL-17F, IL-10, IL-5, and IL-9 by donors’ cells and production of IFNγ, TNFα, IL-22, IL-2, IL-4, IL-5, IL-13, and IL-9 by cells from patients with PsA decreases relative to production of cells stimulated with IL-7. In donors, the blockade contributed to a change in the balance of Th1/Th2 cytokines: level of IL-4, IL-13 did not change on the background of a decrease in production of IFNγ, TNFα. In patients with PsA, under blockade of IL-7R the production of IL-10 remained at an increased level and concentration of IFNγ, TNFα and IL-2, which are actively involved in the tissue damage mechanisms, decreased. The obtained data indicate the prospect of using the IL-7R as a target for the treatment of psoriatic diseases.

EDIL3 alleviates Mannan-induced psoriatic arthritis by slowing the intracellular glycolysis process in mononuclear-derived dendritic cells.

Psoriatic arthritis (PsA) is an immune-mediated, chronic inflammatory joint disease that commonly occurs as a complication of psoriasis. EGF-like repeats and discoidal I-like domain 3 (EDIL3) is a secreted protein with multiple structural domains and associated with various physiological functions. In this study, we employed a mannan-induced psoriatic arthritis model to investigate the impact of EDIL3 on PsA pathogenesis. Notably, a downregulation of EDIL3 expression was observed in the PsA model, which correlated with increased disease severity. EDIL3 knockout mice exhibited a more severe phenotype of PsA, which was ameliorated upon re-infusion of recombinant EDIL3 protein. The mitigation effect of EDIL3 on PsA depends on its regulation of the activation of monocyte-derived DCs (MoDCs) and T-help 17 cells (Th17). After inhibiting the function of MoDCs and Th17 cells with neutralizing antibodies, the beneficial effects of EDIL3 on PsA were lost. By inducing adenosine monophosphate (AMP)-activated protein kinase (AMPK) phosphorylation and suppressing protein kinase B (AKT) phosphorylation, EDIL3 attenuates intracellular glycolysis in MoDCs stimulated by glucose, thereby impeding their maturation and differentiation. Moreover, it diminishes the differentiation of Th17 cells and decelerates the progression of PsA. In conclusion, our findings elucidate the role and mechanism of EDIL3 in the development of PsA, providing a new target for clinical diagnosis and treatment.

Evaluation of CD4+ CD25+/high CD127low/- Regulatory T-Cells in Different Stages of Psoriatic Arthritis Patients.

Psoriatic arthritis (PsA) is a systemic auto-immune condition characterized by diverse and distinctive inflammation, affecting both musculoskeletal and extra-articular systems. This study aims to investigate the role of regulatory T-cells (Tregs), specifically the CD4+CD25+/high CD127-/low subset, in PsA pathogenesis, and their potential as biomarkers and therapeutic targets. In a case-control study involving 40 PsA patients and 25 healthy individuals, CD4+ CD25+/high CD127-/low Tregs were analyzed in peripheral blood mononuclear cells (PBMCs) using flow cytometry. Disease activity was assessed using the Disease Activity in Psoriatic Arthritis (DAPSA) score. We observed a significant positive correlation between Treg levels and the DAPSA score (P = 0.02) in non-treated PsA patients. Additionally, patient age showed a significant positive correlation with erythrocyte sedimentation rate in the same group (P = 0.04), emphasizing the potential influence of Tregs on disease activity and age-related effects on inflammatory markers in PsA. While not revealing significant differences in Treg populations, our research underscores the importance of considering specific Treg subsets in PsA. These subsets may respond differently to disease micro-environments and treatments, affecting disease progression. This study contributes to the broader comprehension of immune dysregulation in auto-immune diseases and suggests that further investigation into Treg subsets' function and count is warranted. Such insights may lead to more tailored therapeutic approaches for PsA patients.

Exploring the Role of Microbiome Alterations in the Pathogenesis of Psoriatic Arthritis: A Multidisciplinary Approach

Psoriatic arthritis (PsA) is a complex, chronic inflammatory disease with intertwined dermatological and rheumatological manifestations, profoundly affecting patients’ quality of life. Recent advances have highlighted the potential role of microbiome alterations, both in the gut and skin, in the pathogenesis of PsA. This review synthesizes current research on the microbiome’s involvement in PsA, emphasizing the interplay between microbial dysbiosis and immune system modulation. Emerging evidence suggests that shifts in the composition and function of the gut and skin microbiota can trigger or exacerbate PsA by promoting systemic inflammation and autoimmune responses. Studies have identified specific microbial taxa associated with PsA, revealing potential biomarkers for early diagnosis and therapeutic targets. However, the precise mechanisms through which microbiome alterations influence PsA pathophysiology remain incompletely understood. Future research should focus on longitudinal studies to further understand the causal relationships between microbiome changes and PsA onset and progression. Integrating varying approaches, including metagenomics, transcriptomics, and metabolomics, will provide a comprehensive understanding of microbial functions and host-microbiome interactions. Additionally, investigating the effects of microbiome-modulating interventions, such as probiotics, prebiotics, and dietary modifications, could guide innovative therapeutic strategies. This multidisciplinary approach, combining dermatological and rheumatological insights, holds promise for unraveling the complexities of PsA and improving patient outcomes through personalized medicine. By advancing our knowledge of

Type-I interferon pathway and DNA damage accumulation in peripheral blood of patients with psoriatic arthritis.

The abnormal DNA damage response is associated with upregulation of the type-1 interferon (IFN-I) pathway in certain rheumatic diseases. We investigated whether such aberrant mechanisms operate in psoriatic arthritis (PsA). DNA damage levels were measured by alkaline comet assay in peripheral blood mononuclear cells from 52 PsA patients and age-sex-matched healthy individuals. RNA expression of IFIT1, MX1 and IFI44, which are selectively induced by IFN-I, was quantitated by real-time polymerase chain reaction and their composite normalized expression resulted in IFN-I score calculation. RNA expression of IL1β, IL6, TNF, IL17A and IL23A was also assessed in PsA and control subgroups. In PsA, DNA damage accumulation was increased by almost two-fold compared to healthy individuals (olive tail moment arbitrary units, mean ± SD; 9.42 ± 2.71 vs 4.88 ± 1.98, p<0.0001). DNA damage levels significantly correlated with serum C-Reactive-protein and IL6 RNA expression in PBMCs. Despite increased DNA damage, the IFN-I score was strikingly lower in PsA patients compared to controls (-0.49 ± 6.99 vs 4.24 ± 4.26; p<0.0001). No correlation was found between IFN-I pathway downregulation and DNA damage. However, the IFN-I score in a PsA subgroup was lower in those patients with higher IL1β expression, as well as in those with higher TNF/IL23A PBMCs expression. DNA damage in PsA correlates with measures of inflammation but is not associated with the IFN-I pathway induction. The unexpected IFN-I downregulation, albeit reminiscent to findings in experimental models of spondyloarthritis, may be implicated in PsA pathogenesis and explained by operation of other cytokines.

Gamma-glutamyl transpeptidase and indirect bilirubin may participate in systemic inflammation of patients with psoriatic arthritis

BackgroundPrevious studies have suggested that systemic metabolic abnormalities are closely related to psoriatic arthritis (PsA). Gamma-glutamyl transpeptidase (GGT) and indirect bilirubin (IBIL), two essential active substances in hepatic metabolism that have been demonstrated as an oxidative and anti-oxidative factor respectively, have been proved to be involved in oxidative stress damage and inflammation in several human diseases. However, their role in PsA remains unclear.MethodsIn this retrospective comparative cohort study, a case group of 68 PsA patients and a control group of 73 healthy volunteers from the Third Hospital of Hebei Medical University were enrolled. Serum GGT, IBIL, GGT/IBIL ratio and C-reactive protein (CRP), a well applied bio-marker of systemic inflammatory in PsA, were compared between the two groups. Furthermore, the relationship of GGT, IBIL and GGT/IBIL with CRP were explored in PsA patients. Finally, the patients were divided into high inflammation group and low inflammation group according to the median value of CRP. Multivariate logistic regression analyses were used for the association of systemic inflammation level with GGT, IBIL and GGT/IBIL.ResultsCompared with healthy controls, PsA patients exhibited significantly higher serum GGT, GGT/IBIL, and CRP levels and lower IBIL levels. Serum GGT and GGT/IBIL were positively correlated with CRP, whereas IBIL were negatively correlated with CRP. Binary logistic regression analysis revealed that serum GGT was a risk factor for high CRP in PsA, whereas IBIL was a protective factor. Furthermore, GGT/IBIL was a better indicator of high CRP condition in PsA patients than either GGT or IBIL alone, as determined by the receiver operating characteristic curves.ConclusionGGT and IBIL may participate in the pathogenesis of PsA. Additionally, GGT, IBIL and the balance of the two may reflect systemic inflammation mediated by oxidative stress events related to metabolic abnormalities to a certain extent.

Dickkopf-Related Protein 1 (DKK-1) as a Possible Link between Bone Erosions and Increased Carotid Intima-Media Thickness in Psoriatic Arthritis: An Ultrasound Study.

Psoriatic arthritis (PsA) is a heterogenous systemic inflammatory disorder that affects peripheral joints and skin, but also causes inflammation at entheseal sites, digits (dactylitis) and the axial skeleton. Despite considerable advances, our understanding of the pathogenesis and management of PsA is hampered by its complex clinical expression. We enrolled patients who met the ClASsification for Psoriatic Arthritis (CASPAR) criteria for PsA (n = 17), and healthy controls (n = 13). The lipid profile, C-reactive protein (CRP) and Dickkopf-related protein 1 (DKK-1) circulating levels were measured for all subjects. For the patients with PsA, (1) the erosive character of the articular disease was assessed by a musculoskeletal ultrasound and (2) the cardiovascular risk was evaluated using the Systematic Coronary Risk Evaluation (SCORE) chart and the ultrasound measurement of the carotid intima-media thickness. A higher titer of serum DKK-1 was associated with the presence of erosions (p < 0.005) and the cIMT correlated with DKK-1 levels in patients with PsA (r = 0.6356, p = 0.0061). Additionally, we observed a positive correlation between increased cIMT and CRP (r = 0.5186, p = 0.0329). Our results suggest that DKK-1 could be used as an early biomarker for the erosive character of the articular disease and for the assessment of the cardiovascular risk in PsA patients.

Comprehensive analysis of mitochondrial DNA variants, mitochondrial DNA copy number and oxidative damage in psoriatic arthritis.

Growing evidence suggests that abnormalities in mitochondrial DNA (mtDNA) are involved in the pathogenesis of various inflammatory and immuno-mediated diseases. The present study analysed the entire mitochondrial genome by next-generation sequencing (NGS) in 23 patients with psoriatic arthritis (PsA) and 20 healthy controls to identify PsA-related variants. Changes in mtDNA copy number (mtDNAcn) were also evaluated by quantitative polymerase chain reaction (qPCR) and mtDNA oxidative damage was measured using an 8-hydroxy-2'-deoxyguanosine assay. NGS analysis revealed a total of 435 variants including 187 in patients with PsA only and 122 in controls only. Additionally, 126 common variants were found, of which 2 variants differed significantly in their frequencies among patients and controls (P<0.05), and may be associated with susceptibility to PsA. A total of 33 missense variants in mtDNA-encoded genes for complexes I, III, IV and V were identified only in patients with PsA. Of them, 25 variants were predicted to be deleterious by affecting the functions and structures of encoded proteins, and 13 variants were predicted to affect protein's stability. mtDNAcn analysis revealed decreased mtDNA content in patients with PsA compared with controls (P=0.0001) but the decrease in mtDNAcn was not correlated with patients' age or inflammatory biomarkers (P>0.05). Moreover, a higher level of oxidative damage was observed in patients with PsA compared with controls (P=0.03). The results of the present comprehensive analysis of mtDNA in PsA revealed that certain mtDNA variants may be implicated in the predisposition/pathogenesis of PsA, highlighting the importance of NGS in the identification of mtDNA variants in PsA. The current results also demonstrated that decreased mtDNAcn in PsA may be a consequence of increased oxidative stress. These data provide valuable insights into the contribution of mtDNA defects to the pathogenesis of PsA. Additional studies in larger cohorts are needed to elucidate the role of mtDNA defects in PsA.

Expression of IL-7 receptor on Th1, Th17 lymphocytes in patients with psoriatic arthritis

Psoriatic arthritis (PsA) is a chronic immune-mediated inflammatory disease of the joints, spine, and entheses that can occur in patients with psoriasis. The prevalence of psoriatic arthritis is high in Russia, in recent years there has been an increase in its incidence rates. The pathogenesis of PsA is based on the activation of Th1, Th17 cells. Pro-inflammatory cytokines produced by the cells are involved in the cascade of reactions leading to the joint deformity and bone destruction. For some autoimmune diseases associated with the Th1/Th17 response, IL-7 has been found to be involved in pathogenetic mechanisms. At the same time, IL-7 is assumed to support autoreactive T lymphocytes. Effect of the cytokine on cells is provided by the binding to a specific receptor thus causing a signal transmission into the cell and inducing the processes of differentiation, proliferation, and production of cytokines. In animal models of autoimmune diseases, usage of blocking antibodies to α-chain of the IL-7 receptor (IL-7R) was shown to cause reduced inflammation in target tissues and decreased number of infiltrating T lymphocytes. Therefore, the aim of this work was to investigate the in vitro effects of IL-7 and blockade of the α-chain of the IL-7 receptor on the contents of Th1, Th17 lymphocytes and expression of IL-7 receptor subunits on these cells in normal subjects and in psoriatic arthritis. The study included nine patients with PsA in the stage of exacerbation of the underlying disease (mean age 44±6.5 years) and 6 healthy individuals (mean age 45±2.7 years). The in vitro effects of IL-7 and specific blocking monoclonal antibodies (aCD127) was evaluated in cultures of mononuclear cells from peripheral blood. Flow cytometry was used to determine the expression of IL-7 receptor subunits (CD127, CD132) and to assess cell phenotypes in peripheral blood and cultured cells. We have shown for the first time that patients with PsA have an increased number of CD127+CD132- and CD127+CD132+ cells among Th17 lymphocytes, as well as CD127+CD132-, CD127+CD132+ and CD127-CD132+ cells among Th1 lymphocytes, which suggests participation of IL-7 in maintaining these cell populations. Upon the in vitro supplement of IL-7, an increase in the Th1 cell contents and a decreased number of Th17 cells were observed, both in donors and PsA patients, and the opposite effect was observed under the conditions of IL-7R of blockade. Under the influence of IL-7, as well as with blocking antibodies, there was a significant decrease in CD127 expression on Th1, Th17 lymphocytes. However, a decrease in the number of CD127-132+ among Th1, Th17 lymphocytes occurred only following blockade with antibodies. That is, despite redistribution of Th1 and Th17 lymphocytes in culture, the cells of these populations were not activated under the IL-7 receptor blockade. The obtained data may serve as a basis for choosing the IL-7 receptor as a target in the development of targeted drugs for the treatment of PsA.

Association of Interleukin-6 and Tumor Necrosis Factor-alpha Gene Polymorphisms with Gnetic Susceptibility of Psoriatic Arthritis in Kuwaiti Arab Patients

Background: Psoriatic arthritis (PsA) is an inflammatory arthritic disease in which joint inflammation occurs with psoriasis. It results from a complex interplay between genetic, immunological and environmental factors. In PsA, the activation of T cells is considered as a crucial step in the disease process. The T-lymphocytes affect the proliferation of epidermal skin cells and result in abnormal differentiation. Altered cytokine networks have been shown to play a central role in the pathogenesis of PsA. Psoriasis is characterized by Th-1 type cytokine pattern in which there is a marked variation in the secretion of interleukin-6 (IL6), interleukin-13 (IL13) and Tumor necrosis factor-alpha (TNF-alpha). This study investigated the association of IL6, IL13 and TNF-alpha gene polymorphisms with genetic susceptibility of PsA in Kuwaiti patients. Methods: The genotypes of IL6 gene (-174G/C; rs1800795), IL13 gene (R130Q; rs20541) and TNF-alpha gene (-308A/G’ rs1800629) polymorphisms were detected in 113 Kuwaiti PsA patients and were compared to that in 104 healthy controls. The PsA patients were diagnosed on the basis of the presence of inflammatory arthritis with psoriasis with no rheumatoid factor in the serum. The genotypes for IL6, IL13 and TNF-alpha gene polymorphisms were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods and were confirmed by DNA sequencing. Results: The frequency of IL6 gene (-174G/C; rs1800795) and TNF-alpha gene (-308A/G’ rs1800629) polymorphisms manifested a statistically significant difference between Kuwaiti PsA patients and controls. However, the frequency of IL13 gene (R130Q; rs20541) polymorphism did not show a significant difference between Kuwaiti PsA patients and the controls. Conclusion: Our data show an association of two cytokine gene polymorphisms in IL6 gene (-174G/C; rs1800795) and TNF-alpha gene (-308A/G’ rs1800629) with PsA in Kuwaiti patients highlighting their significant contribution to genetic susceptibility of this chronic disease possibly along with other factors.

Possible diagnostic accuracy of interleukin − 17A for early diastolic dysfunction in patients with psoriatic arthritis

Psoriatic arthritis (PsA) is influenced by a complex genetic predisposition. In patients with PsA, interleukin (IL)-17A plays a key role in triggering a complex autoimmune/autoinflammatory immune response in conjunction with other pro-inflammatory cytokines (such as tumor necrosis factor-alpha, IL-23, monocyte chemotactic protein-1, and IL-6). PsA manifests with various clinical symptoms, including musculoskeletal diseases and extra-articular manifestations. In particular, mediated by the soluble IL-17A presents a higher cardiovascular risk, suggesting connection between inflammation and cardiovascular diseases beyond the traditional risk factors. Moreover, studies have shown that patients with psoriasis are ten times at higher risk of developing dilated cardiomyopathy than those without psoriasis. Therefore, owing to the prominent role of IL-17A and psoriasis in the pathogenesis of PsA and endothelial dysfunction, we hypothesized that IL-17A is crucial in the early development of diastolic dysfunction (DD) and could serve as a tool to identify patients with asymptomatic DD and PsA. Although transthoracic echocardiography is the primary evaluation method for DD, it requires skilled personnel, routine parameters assessment, such as mitral inflow, and tissue Doppler imaging. As a result, assessing parameters such as left atrial deformity using novel techniques could be valuable for a more specific evaluation and diagnosis of DD. Clinical characteristics and laboratory parameters of PsA activity, cardiac ultrasound parameters, or cardiac functional markers like N-terminal pro-brain natriuretic peptide (NT-pro-BNP) can be correlated with the concentration of serum IL-17A. Moreover, determining the diagnostic accuracy of circulating IL-17A for early DD can also serve as a laboratory biomarker for diagnosing DD in asymptomatic patients. Thus, if the diagnostic accuracy of IL-17A for DD can be proven, the identification of biological drugs that inhibit IL-17A could be advantageous in treating patients with PsA and echocardiography-verified asymptomatic DD.

The Role of Chitinase-3-Like Protein 1(YKL-40) as a Biomarker of Psoriatic Arthritis

Background Psoriatic arthritis (PsA) is a chronic multifaceted inflammatory seronegative arthritis. Plasma YKL-40 is an inflammatory biomarker. Objective To evaluate the role of Chitinase-3-like protein 1 (YKL-40) as a diagnostic biomarker in psoriatic arthritis (PsA) patients and determine its value in assessment of disease activity and severity in PsA patients. Patients and Methods This study included twenty five adult patients with clinical evidence of PsA and twenty five healthy matched age and sex as control group. All underwent history, laboratory investigation, clinical examination, assessment of disease activity using Disease Activity in PSoriatic Arthritis (DAPSA) Score and assessment of severity of PsA using Psoriasis Area and Severity Index (PASI), Nail Psoriasis Severity Index (NAPSI), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Leeds Enthesitis Index (LEI) and examination of dactylitis. Results The mean age of patients was 39.72 ± 11.94. Also, The mean age of healthy controls was 42.88 ± 12.11. There was highly statistically significant difference regarding the serum levels of YKL- 40 (P &amp;lt; 0.01) between the patients and the control groups (P &amp;lt; 0.01). The receiver operating characteristic curve (ROC) curve of YKL -40 showed that the sensitivity and the specificity of YKL- 40 in diagnosis of PsA were 96% and 92% respectively. There were statistically significant positive correlations between YKL- 40 levels (μl/mL) and each of PASI score (p = 0.005) (r = 0.539) and DAPSA score (p = 0.007) (r = 0.526). Conclusion YKL- 40 measurement may serve as a diagnostic biomarker for PsA, as it has the potential to contribute to the fundamental processes underlying the pathogenesis of PsA. So, the results of this study suggested that the addition of YKL- 40 as a serological marker has a valuable role in diagnosis of PsA and reflection of disease activity.

Inflammatory Cytokines in Psoriatic Arthritis: Understanding Pathogenesis and Implications for Treatment.

Psoriatic arthritis (PsA) is a persistent, inflammatory disease that affects individuals with psoriasis, arthritis, and enthesitis. Research has demonstrated that inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin-23 (IL-23), and interleukin-17 (IL-17) play a pivotal role in both the onset and progression of PsA. These cytokines are generated by activated immune cells and stimulate the attraction of inflammatory cells to the synovium and joint tissues, resulting in the deterioration of cartilage and bone. The blocking of these cytokines has become a successful treatment strategy for PsA, as biological drugs that inhibit TNF-α, IL-23, and IL-17 have demonstrated notable clinical benefits. The association between PsA and other types of inflammatory cytokines or chemokines, excluding TNF-α, IL-23, and IL-17, has been extensively investigated in numerous studies. These findings may provide a chance for the discovery of novel therapeutic agents targeting other molecules, distinct from the currently approved biologics and targeted synthetic disease-modifying anti-rheumatic drugs. In this review, we discuss the current understanding of the role of inflammatory cytokines in PsA pathogenesis and clinical implications of targeting these cytokines for PsA treatment.

Serum Interleukin-36 α as a Candidate Biomarker to Distinguish Behçet's Syndrome and Psoriatic Arthritis.

Behçet's syndrome (BS) is a rare systemic vasculitis characterized by different clinical manifestations. As no specific laboratory tests exist, the diagnosis relies on clinical criteria, and the differential diagnosis with other inflammatory diseases can be challenging. Indeed, in a relatively small proportion of patients, BS symptoms include only mucocutaneous, articular, gastrointestinal, and non-typical ocular manifestations, which are frequently found also in psoriatic arthritis (PsA). We investigate the ability of serum interleukin (IL)-36α-a pro-inflammatory cytokine involved in cutaneous and articular inflammatory diseases-to differentiate BS from PsA. A cross-sectional study was performed on 90 patients with BS, 80 with PsA and 80 healthy controls. Significantly lower IL-36α concentrations were found in patients with BS as compared to PsA, although in both groups IL-36α was significantly increased compared to healthy controls. An empirical cut-off of 420.6 pg/mL displayed a specificity of 0.93, with a sensitivity of 0.70 (AUC 0.82) in discriminating PsA from BS. This cut-off displayed a good diagnostic performance also in BS patients lacking highly specific BS manifestations. Our results indicate that IL-36α might be involved in the pathogenesis of both BS and PsA, and might be a candidate biomarker to support the differential diagnosis of BS.

Deucravacitinib for the treatment of psoriatic arthritis: the evidence so far.

Psoriatic arthritis (PsA) is a heterogeneous disease that may develop in up to 30% of patients with psoriasis. PsA mainly involves peripheral joints; however, axial skeleton and entheses can also be involved. PsA is the result of a complex interplay between an individual's genotype and environmental factors that triggers an immune response and leads to the production of a cytokine cascade. Even though there are about 17 targeted therapies for PsA, a significant percentage of patients fail to respond to such treatments, have a partial response or develop side-effects. This article aims to review the current knowledge on deucravacitinib, a new oral small molecule that selectively inhibits tyrosine kinase 2 (TYK2), for the treatment of PsA. TYK2, a member of the Janus kinase (JAK) family, is responsible for mediating intracellular signalling of cytokines involved in the pathogenesis of PsA and psoriasis, namely IL-12, IL-23, and type I interferons. Recently, deucravacitinib was approved by the FDA for the treatment of moderate-to-severe plaque psoriasis and is currently being evaluated in phase III clinical trials in PsA. In a phase II clinical trial, deucravacitinib showed sustained effectiveness in several domains of PsA, namely arthritis, enthesitis and dactylitis, was well tolerated, and had a favourable safety profile. In patients with psoriasis, deucravacitinib had shown a higher efficacy than placebo and apremilast. Deucravacitinib is a promising therapy, with a unique mechanism of action. Results from the phase III programme and studies evaluating long-term response and head-to-head comparisons with other targeted agents will be important to establishing the position of deucravacitinib in the management of PsA.

Characterization of the inflammatory proteome of synovial fluid from patients with psoriatic arthritis: Potential treatment targets.

1) To characterize the inflammatory proteome of synovial fluid (SF) from patients with Psoriatic Arthritis (PsA) using a high-quality throughput proteomic platform, and 2) to evaluate its potential to stratify patients according to clinical features. Inflammatory proteome profile of SF from thirteen PsA patients with active knee arthritis were analyzed using proximity extension assay (PEA) technology (Olink Target 96 Inflammation panel). Four patients with OA were included as control group. Seventy-nine inflammation-related proteins were detected in SF from PsA patients (SF-PsA). Unsupervised analyzes of the molecular proteome profile in SF-PsA identified two specific phenotypes characterized by higher or lower levels of inflammation-related proteins. Clinically, SF-PsA with higher levels of inflammatory proteins also showed increased systemic inflammation and altered glucose and lipid metabolisms. Besides, SF from PsA patients showed 39 out of 79 proteins significantly altered compared to SF-OA specifically related to cell migration and inflammatory response. Among these, molecules such as TNFα, IL-17A, IL-6, IL-10, IL-8, ENRAGE, CCL20, TNFSF-14, OSM, IFNγ, MCP-3, CXCL-11, MCP4, CASP-8, CXCL-6, CD-6, ADA, CXCL-10, TNFβ and IL-7 showed the most significantly change. This is the first study that characterizes the inflammatory landscape of synovial fluid of PsA patients by analyzing a panel of 92 inflammatory proteins using PEA technology. Novel SF proteins have been described as potential pathogenic molecules involved in the pathogenesis of PsA. Despite the flare, inflammatory proteome could distinguish two different phenotypes related to systemic inflammation and lipid and glucose alterations.

Psoriatic Arthritis: Pathogenesis and Targeted Therapies.

Psoriatic arthritis (PsA), a heterogeneous chronic inflammatory immune-mediated disease characterized by musculoskeletal inflammation (arthritis, enthesitis, spondylitis, and dactylitis), generally occurs in patients with psoriasis. PsA is also associated with uveitis and inflammatory bowel disease (Crohn's disease and ulcerative colitis). To capture these manifestations as well as the associated comorbidities, and to recognize their underlining common pathogenesis, the name of psoriatic disease was coined. The pathogenesis of PsA is complex and multifaceted, with an interplay of genetic predisposition, triggering environmental factors, and activation of the innate and adaptive immune system, although autoinflammation has also been implicated. Research has identified several immune-inflammatory pathways defined by cytokines (IL-23/IL-17, TNF), leading to the development of efficacious therapeutic targets. However, heterogeneous responses to these drugs occur in different patients and in the different tissues involved, resulting in a challenge to the global management of the disease. Therefore, more translational research is necessary in order to identify new targets and improve current disease outcomes. Hopefully, this may become a reality through the integration of different omics technologies that allow better understanding of the relevant cellular and molecular players of the different tissues and manifestations of the disease. In this narrative review, we aim to provide an updated overview of the pathophysiology, including the latest findings from multiomics studies, and to describe current targeted therapies.

Upadacitinib for the treatment of psoriatic arthritis.

Psoriatic arthritis is a chronic systemic inflammatory disease that presents with a variable clinical course and is typically associated with joint inflammation, together with cutaneous psoriasis. In recent decades, knowledge of the pathogenesis of psoriatic arthritis has advanced considerably and has allowed for development of new highly effective therapies, transforming the treatment landscape. Upadacitinib is a Janus kinase inhibitor (JAK) that is orally reversible with high selectivity for JAK1 and its signal transduction molecules. The results obtained in the phase III clinical trials (SELECT-PsA 1 and SELEC-PsA 2) demonstrated that upadacitinib was highly effective over placebo and non-inferior to adalimumab in several important domains of the disease. Improvements were observed in dactylitis, enthesitis and spondylitis as well as in physical function, pain, fatigue and overall quality of life. The safety profile of these results resembled that of adalimumab, apart from a slightly higher rate of herpes zoster infection, an increase of creatine kinase and an incidence of lymphopenia. However, none of these events was considered a serious adverse advent. Additionally, another analysis demonstrated that combining upadacitinib with methotrexate was associated with a similar efficacy to upadacitinib in monotherapy, both for patients that are naive to biologics treatment and for those previously treated with biologics. Therefore, upadacitinib is a new option for the treatment of psoriatic arthritis, presenting a series of beneficial characteristics. At this stage, it is important to collect long-term data to confirm the efficacy and safety profiles shown in clinical trials.