Key Signaling Pathways in Psoriasis: Recent Insights from Antipsoriatic Therapeutics

Early Neutrophil Activation in Psoriatic Skin at Relapse Following Dead Sea Climatotherapy

Psoriasis, a chronic inflammatory skin disorder characterised by erythematous and scaly plaques, can be both physically and emotionally distressing for patients. Dead Sea climatotherapy (DSC), a treatment modality combining sun exposure, mineral-rich water and mud therapy during 4 weeks at Ein Gedi, Israel, is used for a small group of patients with psoriasis. This study aimed to investigate the cellular composition of psoriatic skin lesions at relapse after complete clearance from DSC. Skin biopsies from baseline, end of treatment and relapse were collected from eight patients with plaque psoriasis who achieved complete clearance from Dead Sea climatotherapy treatment. These biopsies were subjected to immunohistochemistry, RNA sequencing and quantitative polymerase chain reaction analysis (qPCR). Our findings demonstrate that DSC effectively reduces inflammatory markers to levels comparable to baseline non-lesional skin in the short term. The differential expression analysis identified several upregulated differentially expressed genes, including OSM, CXCL8, TREM1, CXCL1, CSF3R, BCL2A1 and CXCL2, in relapsed psoriasis skin compared with baseline lesional skin. These findings were confirmed by qPCR analysis. Pathway enrichment analysis indicated a marked upregulation of neutrophil-associated pathways in relapse skin compared with baseline lesional skin. Immunohistochemical staining for neutrophil markers, such as CD11b, CD15, CD66b, CD207, MPO and NE, showed a non-significant trend towards enhanced neutrophil infiltration and activation at relapse. In conclusion, while DSC provides short-term effectiveness in managing psoriasis, the initial relapse phase is associated with neutrophil activation and migration. Thus, targeting neutrophils early in the psoriasis disease course may disturb the evolution of psoriasis, potentially preventing disease chronicity.

Probing the dark chemical matter against PDE4 for the management of psoriasis using in silico, in vitro and in vivo approach

The potential downsides for the present treatment for psoriasis are drug resistance, reduced efficacy, risk of mental episodes, and drug interactions. Hence, this study aims to discover a new drug for psoriasis by considering global research efforts and exploring underrepresented chemical space regions. The objective was to identify novel PDE4D inhibitors from the dark chemical matter (DCM) database for treating psoriasis. To address this we have coupled molecular docking and pharmacophore screening with molecular dynamics (MD) to identify hit molecules. Additionally, pharmacokinetics optimization was performed using machine learning and artificial intelligence which are key parts of drug discovery and development processes. The 139,353 DCM molecules were evaluated for their binding mode and interaction with critical residues such as GLN369, ILE336, PHE340, and PHE372 of the phosphodiesterase-4D (PDE4D) enzyme. Here, 15 hits were obtained through successive virtual screening procedures and all the 15 molecules were subjected to MD simulations for hit identification. In the MD studies, a stable root mean square deviation (RMSD) and ligand-protein interactions were found with four molecules, namely 027230, 060628, 060576, and 085881. The ligand 085881 was found promising because it inhibits LPS-induced IL-6 and TNF-alpha secretion from THP-1 cells with IC50 of 18.41 μM and 34.43 μM, respectively. In vivo erythema grading showed that 085881 possesses mild to moderate anti-psoriatic action. This study demonstrates the effective use of computational techniques to discover novel PDE4D inhibitors and provides insight into their therapeutic potential for treating inflammatory diseases such as psoriasis.

Innovative Approaches to Psoriasis: Small Molecules Targeting Key Signaling Pathways

BACKGROUND

Psoriasis (Pso) is a chronic, immune-mediated dermatological condition characterized by dysregulated inflammatory responses and the hyperproliferation of keratinocytes. Biologics, which target specific cytokines such as IL-17 and IL-23, have revolutionized the management by addressing key drivers of its pathophysiology. Despite their efficacy, biologics are not without limitations, including the need for intermittent administration and ongoing monitoring. In contrast, small molecules offer a promising alternative by selectively inhibiting key signaling pathways that modulate pro-inflammatory cytokines involved in the inflammatory cascade.

METHODS AND RESULTS

This review suggests a new therapeutic strategy for Pso treatment, emphasizing the intricate relationships between small molecules and important signaling pathways involved in the pathophysiology of skin conditions. Improving treatment outcomes and reducing the side effects associated with conventional medicines, this review aims to better understand how tailored small-molecule inhibitors might efficiently control these pathways. This creative approach promotes the creation of individualized treatment plans that can greatly enhance the quality of life of patients with Psoby utilizing the knowledge gathered from recent developments in signaling pathway research.

CONCLUSION

This review delves into the molecular mechanisms underlying Pso and explores how small molecules can be harnessed to enhance treatment outcomes, presenting a new paradigm for managing this chronic skin disorder.

Ten-Year Persistence of Biologic Drugs in Psoriasis and Its Relationship with Pharmacogenetic Biomarkers

Background: Psoriasis is a skin disease characterized by the presence of erythematous, scaly plaques on the extensor surfaces of the body. Treatment varies according to the stage of the disease, with the most severe cases being treated with biologic treatments that differ in efficacy and persistence over time. This study aimed to evaluate the 10-year persistence of biologic drugs (adalimumab, etanercept, infliximab and ustekinumab) in the treatment of moderate-to-severe plaque psoriasis. Methods: A total of 143 patients (61 women and 82 men) were evaluated; data were collected from the electronic clinical history, and statistical analysis was performed using the SPSS program. In addition, 115 of them were genotyped in a previous study for 173 immune system genetic polymorphisms. Results: The persistence of biologic drugs at 10 years was 25.9% (95% CI: 17.2-34.5%). Adalimumab was the most persistent drug (41.5%), followed by ustekinumab (34.8%), infliximab (28%) and etanercept (9.3%). The main reason for discontinuation was insufficient efficacy (51%). Adalimumab allowed an increase in the dosing interval in 82.4% of patients who persisted and ustekinumab allowed an increase in 37.5%. The 10-year persistence was related to sex (higher in men, p < 0.001), biologic drug (p = 0.002) and polymorphisms in LMO4 (rs983332) (p = 0.014) and IL20RA (rs1167846) (p = 0.013). Conclusion: The results show that 25% of psoriasis patients treated with first-line biologics persisted at 10 years.

Insight into adenosine pathway in psoriasis: Elucidating its role and the potential therapeutical applications

Psoriasis is an inflammatory skin disease, that can manifest as different phenotypes, however its most common form is psoriasis vulgaris (plaque psoriasis), characterized by abnormal keratinocyte proliferation, leading to characteristic histopathological signs of acanthosis, hyperkeratosis and parakeratosis. For many years, there has been a debate regarding whether keratinocyte dysfunction leads to immune system dysregulation in psoriasis or vice versa. It is now understood that epidermal hyperplasia results from immune system activation. Besides epidermal hyperplasia, psoriatic skin shows leukocyte infiltration, evident angiogenesis in the papillary dermis, characterized by tortuous, dilated capillaries, as well as oedema. There is substantial early evidence that adenosine is a key mediator of the immune response; it derives from ATP hydrolysis and accumulates into tissue in response to systemic and local stress conditions, hypoxia, metabolic stress, inflammation. Adenosine controls several cell functions by signalling through its 4 receptor subtypes, A1, A2A, A2B and A3. Evidence suggests that adenosine may play a role in psoriasis pathogenesis by controlling several immune cell functions, keratinocyte proliferation, neo-angiogenesis. Expression of adenosine receptor varies in psoriatic skin, and this can significantly impact on tissue homeostasis. Indeed, an altered adenosine receptor profile may contribute to the dysregulation observed in psoriasis, affecting immune responses and inflammatory pathways. Here, we discuss the role of adenosine in regulating the functions of the main cell populations implied in the pathogenesis of psoriasis. Furthermore, we give evidence for adenosine signalling pathway as target for therapeutic intervention in psoriasis.

A Narrative Review of the IL-18 and IL-37 Implications in the Pathogenesis of Atopic Dermatitis and Psoriasis: Prospective Treatment Targets

Atopic dermatitis and psoriasis are prevalent inflammatory skin conditions that significantly impact the quality of life of patients, with diverse treatment options available. Despite advances in understanding their underlying mechanisms, recent research highlights the significance of interleukins IL-18 and IL-37, in Th1, Th2, and Th17 inflammatory responses, closely associated with the pathogenesis of psoriasis and atopic dermatitis. Hence, IL-18 and IL-37 could potentially become therapeutic targets. This narrative review synthesizes knowledge on these interleukins, their roles in atopic dermatitis and psoriasis, and emerging treatment strategies. Findings of a literature search up to 30 May 2024, underscore a research gap in IL-37-targeted therapies. Conversely, IL-18-focused treatments have demonstrated promise in adult-onset Still's Disease, warranting further exploration for their potential efficacy in psoriasis and atopic dermatitis.

New and emerging oral therapies for psoriasis

Psoriasis is a chronic inflammatory skin disease affecting 2-3% of the global population. Traditional systemic treatments, such as methotrexate, cyclosporine, acitretin and fumaric acid esters, have limited efficacy and are associated with significant adverse effects, necessitating regular monitoring and posing risks of long-term toxicity. Recent advancements have introduced biologic drugs that offer improved efficacy and safety profiles. However, their high cost and the inconvenience of parenteral administration limit their accessibility. Consequently, there is a growing interest in developing new, targeted oral therapies. Small molecules, such as phosphodiesterase 4 inhibitors (e.g. apremilast) and TYK2 inhibitor (e.g. deucravacitinib), have shown promising results with favourable safety profiles. Additionally, other novel oral agents targeting specific pathways, including IL-17, IL-23, TNF, S1PR1 and A3AR, are under investigation. These treatments aim to combine the efficacy of biologics with the convenience and accessibility of oral administration, addressing the limitations of current therapies. This narrative review synthesizes the emerging oral therapeutic agents for psoriasis, focusing on their mechanisms of action, stages of development and clinical trial results.

Biochanin A Ameliorates Imiquimod-Induced Psoriasis-Like Skin Inflammation in Mice by Modulating the NF-κB and MAPK Signaling Pathways

Psoriasis is a chronic skin inflammatory disorder characterized by the hyper-activation of the immune system and the over-proliferation of epidermal keratinocytes. This study aimed to investigate the anti-psoriatic activity of Biochanin A (BCA), a phytomolecule with known anti-inflammatory and anti-cancer properties, using the IMQ-induced psoriasis-like mouse model. Network pharmacology analysis was performed to investigate the targetability of Biochanin A (BCA) against psoriasis. Psoriasis-like skin inflammation was established using BALB/c mice by topical application of IMQ (5%). BCA cream (0.3%, 1%, 3%) was applied on the skin regions every day for 6 days. The skin phenotypes-erythema and scaling were scored every day. On the 7th day, skin tissues were collected for gene expression analysis, histopathological analysis, cytokine levels determination, and western blot analysis for signaling mechanisms. The network pharmacology analysis has identified 57 common targets between psoriasis and BCA. The topical application of IMQ induced a typical psoriasis-like skin phenotype including redness, skin thickening, and plaque formation. Upon BCA treatment, the psoriasis-like symptoms were significantly reduced in a dose-dependent manner. The targets identified by the network pharmacology (MMP9, EGFR, and PTGS2) and the pro-inflammatory cytokine gene expression were found to be significantly elevated in IMQ controls, and upon BCA treatment they were found significantly reduced. The release of cytokines linked to psoriasis (IL-17A and IL-23) were significantly reduced upon BCA treatment. Furthermore, our findings demonstrated that BCA treatment alleviated the psoriasis-like symptoms via modulating NF-κB and MAPK signaling pathways. Our results demonstrate the therapeutic potential of BCA against IMQ-induced psoriasis-like skin inflammation.

Secukinumab and Dead Sea Climatotherapy Impact Resolved Psoriasis Skin Differently Potentially Affecting Disease Memory

Secukinumab and Dead Sea treatment result in clear skin for many psoriasis patients, through distinct mechanisms. However, recurrence in the same areas after treatments suggests the existence of a molecular scar. We aimed to compare the molecular and genetic differences in psoriasis patients who achieved complete response from secukinumab and Dead Sea climatotherapy treatments. We performed quantitative immunohistochemical and transcriptomic analysis, in addition to digital spatial profiling of skin punch biopsies. Histologically, both treatments resulted in a normalization of the lesional skin to a level resembling nonlesional skin. Interestingly, the transcriptome was not normalized by either treatments. We revealed 479 differentially expressed genes between secukinumab and Dead Sea climatotherapy at the end of treatment, with a psoriasis panel identifying SERPINB4, SERPINB13, IL36G, IL36RN, and AKR1B10 as upregulated in Dead Sea climatotherapy compared with secukinumab. Using digital spatial profiling, pan-RAS was observed to be differentially expressed in the microenvironment surrounding CD103+ cells, and IDO1 was differentially expressed in the dermis when comparing the two treatments. The differences observed between secukinumab and Dead Sea climatotherapy suggest the presence of a molecular scar, which may stem from mechanistically different pathways and potentially contribute to disease recurrence. This may be important for determining treatment response duration and disease memory.

Clostridium botulinum C3bot mediated effects on cytokine-induced psoriasis-like phenotype in full-thickness skin model

Clostridium botulinum C3 exoenzyme (C3bot) exclusively inhibits RhoA, B and C by ADP-ribosylation and is therefore used as a cell-permeable tool for investigating the cellular role of these Rho-GTPases. Rho-GTPases represent a molecular switch integrating different receptor signalling to downstream cascades including transcriptional cascades that regulate various cellular processes, such as regulation of actin cytoskeleton and cell proliferation. C3bot-induced inhibition of RhoA leads to reorganization of the actin cytoskeleton, morphological changes, and inhibition of cell proliferation as well as modulation of inflammatory response. In this study, we characterized the C3bot-mediated effects on a full-thickness skin model exhibiting a psoriasis-like phenotype through the addition of cytokines. Indeed, after the addition of cytokines, a decrease in epidermal thickness, parakeratosis, and induction of IL-6 was detected. In the next step, it was studied whether C3bot caused a reduction in the cytokine-induced psoriasis-like phenotypes. Basal addition of C3bot after cytokine induction of the full-thickness skin models caused less epidermal thinning and reduced IL-6 abundance. Simultaneous basal incubation with cytokines and C3bot, IL-6 abundance was inhibited, but epidermal thickness was only moderately affected. When C3bot was added apically to the skin model, IL-6 abundance was reduced, but no further effects on the psoriasis-like phenotype of the epidermis were observed. In summary, C3bot inhibits the cytokine-induced expression of IL-6 and thus may have an impact on the pro-inflammatory immune response in the psoriasis-like phenotype.

Dynamic Boolean modeling of molecular and cellular interactions in psoriasis predicts drug target candidates

Psoriasis arises from complex interactions between keratinocytes and immune cells, leading to uncontrolled inflammation, immune hyperactivation, and a perturbed keratinocyte life cycle. Despite the availability of drugs for psoriasis management, the disease remains incurable. Treatment response variability calls for new tools and approaches to comprehend the mechanisms underlying disease development. We present a Boolean multiscale population model that captures the dynamics of cell-specific phenotypes in psoriasis, integrating discrete logical formalism and population dynamics simulations. Through simulations and network analysis, the model predictions suggest that targeting neutrophil activation in conjunction with inhibition of either prostaglandin E2 (PGE2) or STAT3 shows promise comparable to interleukin-17 (IL-17) inhibition, one of the most effective treatment options for moderate and severe cases. Our findings underscore the significance of considering complex intercellular interactions and intracellular signaling in psoriasis and highlight the importance of computational approaches in unraveling complex biological systems for drug target identification.

New and Emerging Oral/Topical Small-Molecule Treatments for Psoriasis

The introduction of biologic therapies has led to dramatic improvements in the management of moderate-to-severe psoriasis. Even though the efficacy and safety of the newer biologic agents are difficult to match, oral administration is considered an important advantage by many patients. Current research is focused on the development of oral therapies with improved efficacy and safety compared with available alternatives, as exemplified by deucravacitinib, the first oral allosteric Tyk2 inhibitor approved for the treatment of moderate to severe psoriasis in adults. Recent advances in our knowledge of psoriasis pathogenesis have also led to the development of targeted topical molecules, mostly focused on intracellular signaling pathways such as AhR, PDE-4, and Jak-STAT. Tapinarof (an AhR modulator) and roflumilast (a PDE-4 inhibitor) have exhibited favorable efficacy and safety outcomes and have been approved by the FDA for the topical treatment of plaque psoriasis. This revision focuses on the most recent oral and topical therapies available for psoriasis, especially those that are currently under evaluation and development for the treatment of psoriasis.

Resistin - A Plausible Therapeutic Target in the Pathogenesis of Psoriasis

Resistin, a cytokine hormone predominantly secreted by adipose tissue, is elevated in various metabolic disorders such as obesity, type 2 diabetes, and cardiovascular disease. In addition to its involvement in metabolic regulation, resistin has been implicated in the pathogenesis of psoriasis, a chronic inflammatory skin disorder. Numerous studies have reported increased resistin levels in psoriatic skin lesions, suggesting a possible association between resistin and psoriasis. Recent studies have suggested the potential involvement of resistin in the development and progression of certain cancers. Resistin is overexpressed in breast, colorectal, and gastric cancers. This suggests that it may play a role in the development of these cancers, possibly by inducing inflammation and cell growth. The link between resistin and cancer raises the possibility of shared underlying mechanisms driving the pathogenesis of psoriasis. Chronic inflammation, one such mechanism, is a hallmark of psoriasis and cancer. Further research is needed to fully understand the relationship between resistin and psoriasis. Identifying potential therapeutic targets is crucial for effective management of psoriasis. By doing so, we may be able to develop more effective treatment options for individuals living with psoriasis and ultimately improve their quality of life. Ultimately, a more comprehensive understanding of the mechanisms underlying the impact of resistin on psoriasis is essential for advancing our knowledge and finding new ways to treat and manage this challenging condition.

Multi-Omics Approach to Improved Diagnosis and Treatment of Atopic Dermatitis and Psoriasis

Psoriasis and atopic dermatitis fall within the category of cutaneous immune-mediated inflammatory diseases (IMIDs). The prevalence of IMIDs is increasing in industrialized societies, influenced by both environmental changes and a genetic predisposition. However, the exact immune factors driving these chronic, progressive diseases are not fully understood. By using multi-omics techniques in cutaneous IMIDs, it is expected to advance the understanding of skin biology, uncover the underlying mechanisms of skin conditions, and potentially devise precise and personalized approaches to diagnosis and treatment. We provide a narrative review of the current knowledge in genomics, epigenomics, and proteomics of atopic dermatitis and psoriasis. A literature search was performed for articles published until 30 November 2023. Although there is still much to uncover, recent evidence has already provided valuable insights, such as proteomic profiles that permit differentiating psoriasis from mycosis fungoides and β-defensin 2 correlation to PASI and its drop due to secukinumab first injection, among others.

Efficacy and Safety of the Heat Shock Protein 90 Inhibitor RGRN-305 in Hidradenitis Suppurativa: A Parallel-Design Double-Blind Trial

Importance

Hidradenitis suppurativa is a painful immune-mediated disorder with limited treatment options; hence, a need exists for new treatments.

Objective

To evaluate the feasibility of heat shock protein 90 inhibition by RGRN-305 as a novel mechanism of action in treating moderate to severe hidradenitis suppurativa.

Design, Setting, and Participants

This was a parallel-design, double-blind, proof-of-concept, placebo-controlled randomized clinical trial conducted between September 22, 2021, and August 29, 2022, at the Department of Dermatology, Aarhus University Hospital in Denmark. The study included a 1- to 30-day screening period, a 16-week treatment period, and a 4-week follow-up period. Eligibility criteria included age 18 years or older and moderate to severe hidradenitis suppurativa with 6 or more inflammatory nodules or abscesses in at least 2 distinct anatomic regions. Of 19 patients screened, 15 patients were enrolled in the study. Intention-to-treat analysis was performed.

Interventions

Patients were randomly assigned (2:1) to receive oral RGRN-305, 250-mg tablet, or matching placebo once daily for 16 weeks.

Main Outcomes and Measures

The primary efficacy end point was the percentage of patients achieving Hidradenitis Suppurativa Clinical Response 50 (HiSCR-50) at week 16. Secondary efficacy end points included HiSCR-75 or HiSCR-90, Hidradenitis Suppurativa Physician's Global Assessment, Dermatology Life Quality Index scores, and a pain numeric rating scale. Safety was assessed by adverse events, physical examinations, clinical laboratory measurements, and electrocardiograms.

Results

A total of 15 patients were enrolled, completed the study, and were included in all analyses (10 [67%] female; median age, 29 [IQR, 23-41] years). The primary end point HiSCR-50 at week 16 was achieved by a higher percentage in the RGRN-305 group (60% [6 of 10]) than in the placebo group (20% [1 of 5]). Improvements were also observed across all secondary end points at week 16, including higher rates of the harder-to-reach HiSCR levels; 50% (5 of 10) achieved HiSCR-75 and 30% (3 of 10) achieved HiSCR-90, whereas none of the placebo-treated patients achieved HiSCR-75 or HiSCR-90. RGRN-305 was well tolerated, with no deaths or serious adverse events, and treatment-emergent adverse events were similarly frequent between the RGRN-305 and placebo groups.

Conclusions and Relevance

The findings of this trial suggest that heat shock protein 90 inhibition by RGRN-305 offers a novel mechanism of action in treating hidradenitis suppurativa, warranting further evaluation in larger trials.

Trial Registration

ClinicalTrials.gov Identifier: NCT05286567.

Insights into Autophagic Machinery and Lysosomal Function in Cells Involved in the Psoriatic Immune-Mediated Inflammatory Cascade

Impaired autophagy, due to the dysfunction of lysosomal organelles, contributes to maladaptive responses by pathways central to the immune system. Deciphering the immune-inflammatory ecosystem is essential, but remains a major challenge in terms of understanding the mechanisms responsible for autoimmune diseases. Accumulating evidence implicates a role that is played by a dysfunctional autophagy-lysosomal pathway (ALP) and an immune niche in psoriasis (Ps), one of the most common chronic skin diseases, characterized by the co-existence of autoimmune and autoinflammatory responses. The dysregulated autophagy associated with the defective lysosomal system is only one aspect of Ps pathogenesis. It probably cannot fully explain the pathomechanism involved in Ps, but it is likely important and should be seriously considered in Ps research. This review provides a recent update on discoveries in the field. Also, it sheds light on how the dysregulation of intracellular pathways, coming from modulated autophagy and endolysosomal trafficking, characteristic of key players of the disease, i.e., skin-resident cells, as well as circulating immune cells, may be responsible for immune impairment and the development of Ps.

Durability and long-term outcomes of biologic therapies in psoriasis

INTRODUCTION

Significant advances in psoriasis treatment have taken place since the introduction of biologics. Tumor necrosis factor inhibitors were the first class of biologics approved and at that time greatly improved psoriasis treatment. However, newer biologics, directed to interleukin(IL)-23/IL-17 pathways central to psoriasis pathogenesis, have improved complete or nearly complete clearance rates and are characterized by an excellent safety profile.Real-world setting experiences have generally confirmed the results of clinical trials, but real-world data regarding newer biologics is relatively scarce.

AREAS COVERED

We provide an extensive review of real-world survival of biologic treatments for moderate to severe psoriasis.

EXPERT OPINION

There is growing and consistent evidence of higher drug survival of IL-23 inhibitors, possibly due to their favorable efficacy and safety profiles, dosing convenience and persistence of response despite treatment interruption; eventual confirmation of their potential role as modifiers of the natural history of psoriasis might provide additional reasons for therapeutic persistence of this class of biologics.

Guselkumab, tildrakizumab, and risankizumab in a real-world setting: drug survival and effectiveness in the treatment of psoriasis and psoriatic arthritis

BACKGROUND

Clinical trials have shown promising results for interleukin-23 inhibitors in the treatment of psoriasis. The drugs have been used in clinical practice since 2017.

OBJECTIVE

To investigate the drug survival and effectiveness of interleukin-23 inhibitors in the treatment of psoriasis and psoriatic arthritis (PsA) in a real-world setting.

METHODS

The study was a retrospective analysis of patients treated with either guselkumab, tildrakizumab, or risankizumab at the Department of Dermatology, Aarhus University Hospital, during the period from June 11 2018, to July 14 2021.

RESULTS

A total of 80 patients were included. During the study, 19 patients discontinued treatment with an interleukin-23 inhibitor, and mean treatment duration (SD) was 61.4 weeks (43.7). Seventy-six patients (95%) had previous use of ≥1 biologic. One-year drug survival was 81.0%. Among patients, 64.3% achieved a Psoriasis Area and Severity Index (PASI) ≤ 2 at weeks 12-17; 61.3%, at weeks 40-60. There was no statistically significant difference between the drugs regarding the chance of achieving PASI ≤ 2 (p>.05). Twenty-two patients (27.5%) had PsA. Among these, 40.9% and 36.4% achieved complete remission and partial remission, respectively.

CONCLUSIONS

Interleukin-23 inhibitors appear to have high and similar drug survival and effectiveness in patients with difficult-to-treat psoriasis and PsA.

Transcriptomic Analysis of Hidradenitis Suppurativa: A Unique Molecular Signature with Broad Immune Activation

Hidradenitis suppurativa is a chronic inflammatory skin disease with limited treatment options. The poorly understood pathogenesis hinders the development of effective treatments; therefore, a pressing need exists to further elucidate the molecular mechanisms in hidradenitis suppurativa. This study investigated the underlying inflammatory pathways and cell types in hidradenitis suppurativa using transcriptomic approaches with RNA sequencing of lesional and non-lesional skin biopsies from hidradenitis suppurativa, which was jointly analyzed with previously published transcriptomic data from atopic dermatitis and psoriasis patients. The differential expression and pathway enrichment analyses demonstrated the activation of multiple inflammatory processes, including the innate and adaptive immune systems, implicated in the hidradenitis suppurativa pathogenesis. In agreement, hidradenitis suppurativa exhibited a unique and heterogeneous cell type signature involving lymphoid and myeloid cells such as B cells and macrophages. Furthermore, hidradenitis suppurativa displayed increased expression of TH1/2/17 signatures with no predominant TH signatures unlike psoriasis (TH1/17) and atopic dermatitis (TH2). In summary, our study provides molecular insights into the pathomechanisms in hidradenitis suppurativa, revealing a strong and widespread immune activation, which may benefit from treatment strategies offering a broad immunomodulation of various key inflammatory pathways. Our data not only corroborate previously reported findings but also enhance our understanding of the immune dysregulation in hidradenitis suppurativa, uncovering novel and potential therapeutic targets.

Signaling pathways and targeted therapies for psoriasis

Psoriasis is a common, chronic, and inflammatory skin disease with a high burden on individuals, health systems, and society worldwide. With the immunological pathologies and pathogenesis of psoriasis becoming gradually revealed, the therapeutic approaches for this disease have gained revolutionary progress. Nevertheless, the mechanisms of less common forms of psoriasis remain elusive. Furthermore, severe adverse effects and the recurrence of disease upon treatment cessation should be noted and addressed during the treatment, which, however, has been rarely explored with the integration of preliminary findings. Therefore, it is crucial to have a comprehensive understanding of the mechanisms behind psoriasis pathogenesis, which might offer new insights for research and lead to more substantive progress in therapeutic approaches and expand clinical options for psoriasis treatment. In this review, we looked to briefly introduce the epidemiology, clinical subtypes, pathophysiology, and comorbidities of psoriasis and systematically discuss the signaling pathways involving extracellular cytokines and intracellular transmission, as well as the cross-talk between them. In the discussion, we also paid more attention to the potential metabolic and epigenetic mechanisms of psoriasis and the molecular mechanistic cascades related to its comorbidities. This review also outlined current treatment for psoriasis, especially targeted therapies and novel therapeutic strategies, as well as the potential mechanism of disease recurrence.

Australian consensus: Treatment goals for moderate to severe psoriasis in the era of targeted therapies - Adult patients

BACKGROUND

Over the last decade, the treatment landscape for moderate-severe psoriasis has rapidly evolved. The Australasian College of Dermatologists sought to review and update previously published treatment goals for moderate-severe psoriasis.

METHODS

A modified Delphi approach was used. Comprehensive literature review and guideline evaluation resulted in the development of statements and other questions to establish current clinical practices. Two rounds of anonymous voting were undertaken, with a collaborative meeting held in between to discuss areas of discordance. Overall, consensus was defined as achievement of ≥75% agreement in the range 7-9 on a 9-point scale (1 strongly disagree; 9 strongly agree).

RESULTS

Consensus was achieved on 26/29 statements in round 1 and a further 20 statements in round 2. There was strong agreement to expanding the classification/definition of psoriasis severity by including a choice of metrics, incorporating quality of life measures, and widening the scope of high-impact sites. Consensus was also reached on revised treatment response criteria, which were then incorporated into a new treatment algorithm. There was discordance with the current requirement to undertake a trial with established systemic agents before accessing targeted therapy.

CONCLUSION

The ability of new targeted treatment options to change the narrative in psoriasis patient care can only be properly realised if challenges to timely and equitable access are addressed. The proposed framework for the assessment, classification and management of moderate-severe psoriasis aligns with international recommendations. Its adoption into Australian clinical practice is hoped to improve treatment outcomes and patients' satisfaction with their care.

Psoriasis: a focus on upcoming oral formulations

INTRODUCTION

Targeted therapies have greatly improved the quality of life of patients with psoriasis. Despite the extensive list of treatments available, multiple new drugs are being developed, especially oral therapies with potential advantages as regards comfort of administration. However, the efficacy and safety of these new oral therapies need to be improved to match those of novel biologics.

AREAS COVERED

We provide a narrative review of the oral therapies for psoriasis that are currently under development, from Jak inhibitors to oral IL-17 and IL-23 inhibitors, among others. A literature search was performed for articles published from 1 January 2020, to 6 June 2023.

EXPERT OPINION

The approval of deucravacitinib, the first Jak inhibitor for the treatment of moderate-to-severe plaque psoriasis, heralds a bright therapeutic future with multiple new oral formulations. A great number of oral treatments with singular mechanism of action, like A3AR agonists, HSP90 inhibitors, ROCK-2 inhibitors, oral TNF inhibitors, oral IL-23 inhibitors, oral IL-17 inhibitors, PD4 inhibitors (orismilast) and several Tyk2 inhibitors, are currently being evaluated in clinical trials and could be suitable for approval in the future. Growing variation in treatment modes of administration will allow dermatologists to better integrate patient preferences in the therapeutic decision process.

Bimekizumab in the Treatment of Plaque Psoriasis: Focus on Patient Selection and Perspectives

Psoriasis is a chronic systemic inflammatory disease that significatively impairs patients' quality of life. Biological treatments are highly effective and safe and have led to breakthroughs in the management of patients with moderate-to-severe psoriasis. However, therapeutic response can be unsatisfactory or lost with time, leading to discontinuation of treatment. Bimekizumab is a humanized monoclonal antibody that specifically inhibits both interleukin (IL)-17A and IL-17F. The efficacy and safety of bimekizumab in moderate-to-severe plaque psoriasis has been demonstrated in Phase 2 and Phase 3 clinical trials. Bimekizumab may offer some advantages over other biological treatments, making it especially indicated for certain patients. This narrative review aims to summarize the latest published evidence on the use of bimekizumab for the treatment of moderate-severe plaque psoriasis, focusing on patient selection and therapeutic perspectives. Bimekizumab has been shown to be more efficacious than adalimumab, secukinumab and ustekinumab in clinical trials, with high estimated probabilities of achieving complete (approximately 60%) or almost complete clearance (approximately 85%) of psoriasis at weeks 10-16, and a good safety profile. Response to bimekizumab is usually fast and maintained in the long term for both biologic-naive patients and those resistant to previous biologic treatments. The usual maintenance dose of 320 mg every 8 weeks makes bimekizumab especially convenient for non-compliant patients. Moreover, the efficacy and safety of bimekizumab have also been demonstrated in psoriasis affecting challenging-to-treat areas, psoriatic arthritis and hidradenitis suppurativa. In conclusion, dual inhibition of IL-17A and IL-17F with bimekizumab is a good therapeutic option for moderate-to-severe psoriasis.

Molecular treatment trajectories within psoriatic T lymphocytes: a mini review

Multiple biological processes in mammalian cells are implicated in psoriasis (Ps) development and progression, as well as in the pathogenic mechanisms associated with this chronic immune-mediated inflammatory disease (IMID). These refer to molecular cascades contributing to the pathological topical and systemic reactions in Ps, where local skin-resident cells derived from peripheral blood and skin-infiltrating cells originating from the circulatory system, in particular T lymphocytes (T cells), are key actors. The interplay between molecular components of T cell signalling transduction and their involvement in cellular cascades (i.e. throughout Ca2+/CaN/NFAT, MAPK/JNK, PI3K/Akt/mTOR, JAK/STAT pathways) has been of concern in the last few years; this is still less characterised than expected, even though some evidence has accumulated to date identifying them as potential objects in the management of Ps. Innovative therapeutic strategies for the use of compounds such as synthetic Small Molecule Drugs (SMDs) and their various combinations proved to be promising tools for the treatment of Ps via incomplete blocking, also known as modulation of disease-associated molecular tracks. Despite recent drug development having mainly centred on biological therapies for Ps, yet displaying serious limitations, SMDs acting on specific pathway factor isoforms or single effectors within T cell, could represent a valid innovation in real-world treatment patterns in patients with Ps. Of note, due to the intricate crosstalk between intracellular pathways, the use of selective agents targeting proper tracks is, in our opinion, a challenge for modern science regarding the prevention of disease at its onset and also in the prediction of patient response to Ps treatment.

The elucidation of structure-activity and structure-permeation relationships for the cutaneous delivery of phytosterols to attenuate psoriasiform inflammation

Phytosterols have been reported to exert anti-inflammatory activity. This study aimed to investigate the capacity of campesterol, β-sitosterol, and stigmasterol on the mitigation of psoriasiform inflammation. We also tried to establish structure-activity and structure-permeation relationships for these plant sterols. To support this study, we first approached the in silico data of the physicochemical properties and the molecular docking of phytosterols with stratum corneum (SC) lipids. The anti-inflammatory activity of the phytosterols was explored in the activated keratinocytes and macrophages. Using the activated keratinocyte model, a significant inhibition of IL-6 and CXCL8 overexpression by phytosterols was detected. A comparable inhibition level was found for the three phytosterols tested. The macrophage-based study showed that the anti-IL-6 and anti-CXCL8 activities of campesterol were greater than those of the other compounds, which indicated that a phytosterol structure without a double bond on C₂₂ and with methyl moiety on C₂₄ was more effective. The conditioned medium of phytosterol-treated macrophages decreased STAT3 phosphorylation in the keratinocytes, suggesting the inhibition of keratinocyte hyperproliferation. β-sitosterol was the penetrant with the highest pig skin absorption (0.33 nmol/mg), followed by campesterol (0.21 nmol/mg) and stigmasterol (0.16 nmol/mg). The therapeutic index (TI) is a parameter measured by multiplying the cytokine/chemokine suppression percentage with skin absorption for anticipating the anti-inflammatory activity after topical delivery. β-sitosterol is a potential candidate for treating psoriatic inflammation due to having the greatest TI value. In this study, β-sitosterol attenuated epidermal hyperplasia and immune cell infiltration in the psoriasis-like mouse model. The psoriasiform epidermis thickness could be reduced from 92.4 to 63.8 μm by the topical use of β-sitosterol, with a downregulation of IL-6, TNF-α, and CXCL1. The skin tolerance study manifested that the reference drug betamethasone but not β-sitosterol could generate barrier dysfunction. β-sitosterol possessed anti-inflammatory activity and facile skin transport, showing the potential for development as an anti-psoriatic agent.

Perspective insights of small molecules, phytoconstituents and biologics in the management of psoriasis: A focus on targeting major inflammatory cytokine pathways

Psoriasis is an enduring, pruritic and papulosquamous skin ailment that poses a significant burden on public health. It is mainly characterized by hyperkeratosis, acanthosis, parakeratosis, scaly and erythematous plaques. Biomarkers like interleukin-17, interleukin-12 and -23 and tumor necrosis factor-α serve as key drivers of psoriatic pathogenesis. Triggered release of pro-inflammatory cytokines from various up-regulated pathways leads to psoriatic inflammation. Several target moieties like biologics, small molecules and herbal moieties play a fundamental role in the repression of pathogenesis of psoriasis. Biologics and small molecules engaged in the management of psoriasis have been emphasized in detail. An insight into nano-carrier interventions on herbal moieties and clinical aspects of psoriasis are also highlighted. This review emphasizes various pathological targets involved in psoriasis.

Heat shock protein 90 inhibitor RGRN-305 potently attenuates skin inflammation

Introduction

Chronic inflammatory skin diseases may have a profound negative impact on the quality of life. Current treatment options may be inadequate, offering an unsatisfactory response or side effects. Therefore, ongoing efforts exist to identify novel effective and safe treatments. Heat shock protein (HSP) 90 is a chaperone that promotes the activity of a wide range of client proteins including key proinflammatory molecules involved in aberrant inflammation. Recently, a proof-of-concept clinical trial of 13 patients suggested that RGRN-305 (an HSP90 inhibitor) may be an oral treatment for psoriasis. However, HSP90 inhibition may be a novel therapeutic approach extending beyond psoriasis to include multiple immune-mediated inflammatory skin diseases.

Methods

This study aimed to investigate (i) the anti-inflammatory effects and mechanisms of HSP90 inhibition and (ii) the feasibility of topical RGRN-305 administration (new route of administration) in models of inflammation elicited by 12-O-tetradecanoylphorbol-13-acetate (TPA) in primary human keratinocytes and mice (irritative dermatitis murine model).

Results/Discussion

In primary human keratinocytes stimulated with TPA, a Nanostring® nCounter gene expression assay demonstrated that HSP90 inhibition with RGRN-305 suppressed many proinflammatory genes. Furthermore, when measured by quantitative real-time polymerase chain reaction (RT-qPCR), RGRN-305 significantly reduced the gene expression of TNF, IL1B, IL6 and CXCL8. We next demonstrated that topical RGRN-305 application significantly ameliorated TPA-induced skin inflammation in mice. The increase in ear thickness (a marker of inflammation) was significantly reduced (up to 89% inhibition). In accordance, RT-qPCR of the ear tissue demonstrated that RGRN-305 robustly reduced the gene expression of proinflammatory markers (Tnf, Il1b, Il6, Il17A and Defb4). Moreover, RNA sequencing revealed that RGRN-305 mitigated TPA-induced alterations in gene expression and suppressed genes implicated in inflammation. Lastly, we discovered that the anti-inflammatory effects were mediated, at least partly, by suppressing the activity of NF-κB, ERK1/2, p38 MAPK and c-Jun signaling pathways, which are consistent with previous findings in other experimental models beyond skin inflammation. In summary, HSP90 inhibition robustly suppressed TPA-induced inflammation by targeting key proinflammatory cytokines and signaling pathways. Our findings suggest that HSP90 inhibition may be a novel mechanism of action for treating immune-mediated skin disease beyond psoriasis, and it may be a topical treatment option.

Biologic treatment of psoriasis in oncologic patients

INTRODUCTION

There is a complex interplay between psoriasis and cancer, with therapeutic implications. Patients with psoriasis have an increased risk of developing several types of cancer, and safety concerns have arisen regarding biologic therapies and cancer. On the other hand, biologics can provide adequate control of psoriasis that appears or worsens as an immune-related adverse event following immune enhancing checkpoint inhibitor therapy for cancer, thus allowing prosecution of oncologic treatment without impairing its efficacy.

PATIENTS AND METHODS

We performed a retrospective observational study of patients with moderate-to-severe psoriasis under biological treatment and cancer who were treated at our Department between January 2009 and June 2022.

RESULTS

We included 31 adult patients with psoriasis and cancer; in 16 the diagnosis of cancer preceded the inception of biological treatment, and 9 of those patients were in remission. Most malignancies arose in the genitourinary system, followed by breast, hematologic, colorectal, thyroid, and others. Anti-IL23p19 biologics were most frequently used (36%), followed by anti-TNF (32%), anti-IL-17 (16%) and anti-IL-12/23 (16%) agents. All patients showed improvement of psoriasis after biologic initiation.

CONCLUSIONS

Biologic treatment for moderate-severe psoriasis should be considered in oncologic patients since it is not formally contraindicated and is safe. Moreover, the efficacy and safety profile of IL-23 and IL-17 inhibitors may be advantageous for those patients.

Effectiveness, survival and safety of guselkumab attending to basal characteristics in moderate-to-severe psoriatic patients: a cohort study

Background: Psoriasis is a chronic inflammatory disease which can impact quality of life. In the past decade multiple biologic treatments have been released with encouraging results. Guselkumab is a monoclonal antibody targeting IL-23p19. Multiple randomized clinical trials have demonstrated its efficacy in psoriasis, but response differences among patient subpopulations have not been extensively reported. Furthermore, patients in real life are often non-eligible for clinical trials and their responses may differ from pivotal studies. Methods: This is a retrospective, observational study of real clinical practice of patients receiving guselkumab treatment in Spain. Patients treated with guselkumab were included between February 2019 to December 2021. This study evaluates the potential differential effect of baseline demographic and disease characteristics on therapeutic responses to guselkumab. We measured effectiveness and survival by the psoriasis area and severity index, the dermatology life quality index as well as Kaplan meier curves, respectively. Categorical and quantitative variables are reported with frequencies, and with mean and standard deviation, respectively. Differences between groups in psoriasis area and severity index and dermatology life quality index, were calculated using a mixed-effects analysis. Survival was calculated using Kaplan meier curves and log-rank tests. Results: A total of 87 patients were included. In this study, our objective was to evaluate the effectiveness, safety and survival of guselkumab attending to demographic characteristics. No differences in psoriasis area and severity index or dermatology life quality index baseline values or therapeutic responses were noted at 52 weeks of follow-up among all the subgroups analysed (age, sex, psoriasis duration, body mass index, and comorbidities). A difference in drug survival was only seen between gender groups. Conclusions: Our research has demonstrated the consistency of guselkumab effectiveness across patient subgroups. No baseline features affected the effectiveness or drug survival of guselkumab, except for lower drug survival in female patients.

Effectiveness, survival and safety of guselkumab attending to basal characteristics in moderate-to-severe psoriatic patients: a cohort study

Background: Psoriasis is a chronic inflammatory disease which can impact quality of life. In the past decade multiple biologic treatments have been released with encouraging results. Guselkumab is a monoclonal antibody targeting IL-23p19. Multiple randomized clinical trials have demonstrated its efficacy in psoriasis, but response differences among patient subpopulations have not been extensively reported. Furthermore, patients in real life are often non-eligible for clinical trials and their responses may differ from pivotal studies. Methods: This is a retrospective, observational study of real clinical practice of patients receiving guselkumab treatment in Spain. Patients treated with guselkumab were included between February 2019 to December 2021. This study evaluates the potential differential effect of baseline demographic and disease characteristics on therapeutic responses to guselkumab. We measured effectiveness and survival by the psoriasis area and severity index, the dermatology life quality index as well as Kaplan meier curves, respectively. Categorical and quantitative variables are reported with frequencies, and with mean and standard deviation, respectively. Differences between groups in psoriasis area and severity index and dermatology life quality index, were calculated using a mixed-effects analysis. Survival was calculated using Kaplan meier curves and log-rank tests. Results: A total of 87 patients were included. In this study, our objective was to evaluate the effectiveness, safety and survival of guselkumab attending to demographic characteristics. No differences in psoriasis area and severity index or dermatology life quality index baseline values or therapeutic responses were noted at 52 weeks of follow-up among all the subgroups analysed (age, sex, psoriasis duration, body mass index, and comorbidities). A difference in drug survival was only seen between gender groups. Conclusions: Our research has demonstrated the consistency of guselkumab effectiveness across patient subgroups. No baseline features affected the effectiveness or drug survival of guselkumab, except for lower drug survival in female patients.

Treatments for psoriasis: A journey from classical to advanced therapies. How far have we reached?

Psoriasis is considered an autoimmune, inflammatory disorder with a genetic basis. The underlying aetiology is yet unclear. Evidence suggests the congregation of immune cells and their secreted inflammatory cytokines, leukocytes, and other inflammation-promoting factors in large amounts within the epidermal layers of the skin, driving an inflammatory milieu. Although psoriasis is not a fatal condition, patients experience severe pain and suffering. It has a debilitating effect on the physiological and psychological state of the patient. Its distinguishing features are inflammation, formation of plaques on the skin and hyperproliferation of keratinocytes. Therapeutic strategies for treating psoriasis witnessed a radical improvement from traditional therapies to the approval of specific therapies like biologics and small molecules. The emerging evidence about new pharmacological targets and mechanisms in psoriasis has widened the scope for expanding therapeutic strategies. Our review discusses the existing treatments for plaque psoriasis and updates on therapies based on novel pharmacological targets in clinical development.

Exploring the Links between Obesity and Psoriasis: A Comprehensive Review

Obesity is a major public health issue worldwide since it is associated with the development of chronic comorbidities such as type 2 diabetes, dyslipidemias, atherosclerosis, some cancer forms and skin diseases, including psoriasis. Scientific evidence has indicated that the possible link between obesity and psoriasis may be multifactorial, highlighting dietary habits, lifestyle, certain genetic factors and the microbiome as leading factors in the progress of both pathologies because they are associated with a chronic pro-inflammatory state. Thus, inflammation management in obesity is a plausible target for psoriasis, not only because of the sick adipose tissue secretome profile but also due to the relationship of obesity with the rest of the immune derangements associated with psoriasis initiation and maintenance. Hence, this review will provide a general and molecular overview of the relationship between both pathologies and present recent therapeutic advances in treating this problem.

Climatotherapy at the Dead Sea for psoriasis is a highly effective anti-inflammatory treatment in the short term; an immunohistochemical study

Climatotherapy is a well‐described treatment of psoriasis. Dead Sea climatotherapy (DSC) in Israel consists of intensive sun and Dead Sea bathing and is very effective in improving clinical and patient‐reported outcomes. However, the effect of DSC has not been widely studied. We aimed to investigate the effect of DSC on psoriasis skin using quantitative immunohistochemistry techniques and analysis of blood samples. Skin punch biopsies from 18 psoriasis patients from a previous cohort study were used. Biopsies were obtained from non‐lesional skin and from a psoriasis target lesion at baseline. A biopsy was acquired from the target lesion after DSC. Among patients who achieved complete visual clearance, a biopsy was also obtained at relapse. Blood samples were obtained at the same time points. We performed haematoxylin and eosin staining and quantitative immunohistochemical analysis of CD3, CD4, CD8, CD11c, CD103, CD163, CD207, forkhead box P3, Ki67 and myeloperoxidase. We performed blood tests of cholesterol, c‐reactive protein, glucose, haemoglobin A1c and triglycerides. All skin biomarkers except for CD207 were decreased after DSC. At relapse, none of the biomarkers were significantly different from the baseline lesional measurements. Total CD207 staining correlated with psoriasis area and severity index at baseline while CD163 staining correlated with psoriasis area and severity index at EOT. No changes were observed in selected blood tests during the study. Consistent with clinical results, DSC is highly effective in the short term almost normalising all investigated biomarkers. However, at relapse, biomarkers were upregulated to the baseline level.

Cytokine Profiles and the Relationship of Disease Severity in Patients with Psoriasis

Background

Psoriasis is a chronic skin disease characterized by hyperproliferation of keratinocytes and increased inflammation. Previous studies have detected the levels of cytokines in the serum of patients with psoriasis, yet few multi-cytokine combination studies have been reported.

Objective

The aim of the study was to compare the levels of cytokines in the serum between patients with psoriasis and healthy controls, elucidate which factors influence the psoriasis progression.

Methods

A total of 39 psoriasis patients and 30 healthy volunteers were enrolled. The venous blood was collected and the levels of 13 inflammatory cytokines were measured by human inflammation panel 1 kit. The severity of the disease was determined according to the psoriasis area and severity index (PASI) score.

Results

Compared with healthy controls, the levels of nine cytokines (IFN-γ, TNF-α, IL-1β, IL-6, IL-10, IL-12P40, IL-18, IL-17A and IL-23) were significantly increased, while the level of MCP-1 decreased in psoriatic patients. In addition, except for MCP-1, IL-10 and IL-12P40, these cytokine levels were positively correlated with the PASI score. Furthermore, there were higher serum lever of IFN-γ, TNF-α, IL-1β, IL-6, IL-17A, IL-18 and IL-23 in active psoriasis than healthy controls and retrograde psoriasis.

Conclusions

Increased serum levels of IFN-γ, TNF-α, IL-1β, IL-6, IL-17A, IL-18 and IL-23 in psoriatic patients were associated with PASI and the stage of disease, which suggested that these cytokines play an important role in the pathogenesis of psoriasis. The detection of these cytokines can better observe the disease activity of psoriasis and optimize the treatment strategy.

Recent Update on Immunopathogenesis of Psoriasis

Psoriasis is a chronic disabling complex inflammatory disorder prevalent worldwide with environmental and genetic components that involve predominantly skin in addition to nails and joints associated with various systemic comorbidities having periods of exacerbations and remissions. Psoriasis is characterized by hyper-proliferation as well as abnormal differentiation of epidermal keratinocytes and lymphocyte infiltration (mainly T cells) with resultant inflammatory cytokines and chemokines. Immunological and genetic studies over the last decade have identified genetic susceptibility risk alleles, molecular, cellular and immunological mechanisms involved in immunopathogenesis of psoriasis. The current disease model emphasizes the role of aberrant Th1 and Th17 responses regulated by a complex network of different cytokines, including TNF-α, IL-17 and IL-23; signal transduction pathways downstream to the cytokine receptors; and various activated transcription factors, including NF-κB, interferon regulatory factors and signal transducer and activator of transcriptions. Cytokines targeting biologics (IL-17, IL-23 and TNFα) therapies have revolutionized the management of severe skin disease having beneficial effects on joints and systemic inflammation of psoriasis as well. Further better understanding of immunopathogenesis of psoriasis will pave way for precision medicine based on specific immunopathogenic targets in a given phenotype of disease. Complex interplay of psoriasis with associated comorbidities is also a future area of research for overall better patient management and to improve their quality of life.

Use of Cytokine Mix-, Imiquimod-, and Serum-Induced Monoculture and Lipopolysaccharide- and Interferon Gamma-Treated Co-Culture to Establish In Vitro Psoriasis-like Inflammation Models

Psoriasis (Ps), commonly perceived as a skin and joint disorder, has a complex basis and results from disturbances in the sophisticated network between skin and the immune system. This makes it difficult to properly depict the complete pathomechanism on an in vitro scale. Deciphering the complicated or even subtle modulation of intra- and intercellular factors, assisted by the implementation of in vitro human skin models, may provide the opportunity to dissect the disease background step by step. In addition to reconstructed artificial skin substitutes, which mimic the native physiological context, in vitro models are conducive to the broad "3 Rs" philosophy (reduce, refine, and replace) and represent important tools for basic and applied skin research. To meet the need for a more comprehensive in vitro Ps model, a set of various experimental conditions was applied in this study. The selection of in vitro treatment that mimicked the Ps phenotype was illustrated by analyses of discriminating biomarker genes involved in the pathogenesis of the disease, i.e., keratinocyte differentiation markers, antimicrobial peptides, chemokines, and proliferation markers. This resulted in a reproducible protocol for the use of the primary skin keratinocyte (pKC) monoculture treated with a cytokine cocktail (5MIX, i.e., interleukin (IL) 1 alpha (IL-1α), IL-17A, IL-22, oncostatin M (OSM), and tumour necrosis factor alpha (TNF-α)) at a calcium (Ca2+) concentration (i.e., 2 mM) in an applied medium, which best mirrored the in vitro Ps-like inflammatory model. In addition, based on waste skin material, the method has the potential for extensive experimentation, both in detailed molecular studies and preclinical tests.

Diet-Related Phototoxic Reactions in Psoriatic Patients Undergoing Phototherapy: Results from a Multicenter Prospective Study

Vegans and vegetarians often consume foods containing photosensitizers capable of triggering phytophotodermatitis. The potential effect of vegan and vegetarian diets on the response of psoriatic patients undergoing phototherapy is not well characterized. We assessed clinical outcomes of vegan, vegetarian and omnivore adult psoriatic patients undergoing band ultraviolet B phototherapy (NB-UVB). In this multicenter prospective observational study, we enrolled 119 adult, psoriatic patients, of whom 40 were omnivores, 41 were vegetarians and 38 were vegans, with phototherapy indication. After determining the minimum erythemal dose (MED), we performed NB-UVB sessions for 8 weeks. The first irradiation dosage was 70.00% of the MED, then increased by 20.00% (no erythema) or by 10.00% (presence of erythema) until a maximum single dose of 3 J/cm² was reached and constantly maintained. All the enrolled patients completed the 8 weeks of therapy. Severe erythema was present in 16 (42.11%) vegans, 7 (17.07%) vegetarians and 4 (10.00%) omnivores (p < 0.01). MED was lowest among vegans (21.18 ± 4.85 J/m²), followed by vegetarians (28.90 ± 6.66 J/m²) and omnivores (33.63 ± 4.53 J/m², p < 0.01). Patients with severe erythema were more likely to have a high furocumarin intake (OR 5.67, 95% CI 3.74-8.61, p < 0.01). Vegans consumed the highest amount of furocumarin-rich foods. A model examining erythema, adjusted for gender, age, skin type, MED, phototherapy type, number of phototherapies and furocumarin intake, confirmed that vegans had a lower number of treatments. Vegans had more frequent severe erythema from NB-UVB, even after adjustment of the phototherapy protocol for their lower MED. Assessing diet information and adapting the protocol for vegan patients may be prudent.