Novel therapies for psoriasis

Co-delivery of methotrexate and nicotinamide by cerosomes for topical psoriasis treatment with enhanced efficacy

Psoriasis is an immune-mediated skin disorder that affects populations worldwide. Methotrexate (MTX) is a cytotoxic drug with powerful anti-proliferative and anti-inflammatory effects that has gained prominence in treating inflammatory diseases including psoriasis. However, low solubility and side effects through oral administration hinder its systemic application. In this study, we developed a novel niosomes based on ceramide (cerosomes) to co-deliver MTX and nicotinamide (NIC), i.e., MTX/NIC cerosomes, for topically treating psoriasis with the aim to enhancing the efficacy and reducing the toxicity. NIC significantly solublized MTX by forming hydrogen bonds with MTX. In vitro and in vivo permeation studies showed that the cerosomes significantly promoted drug permeation through and retention in the skin, and the enhancing mechanism was clarified by Fourier transform infraredand Raman spectroscopy. MTX/NIC cerosomes exhibited strong anti-proliferation effect on lipopolysaccharide- irritated HaCaT cells by arresting the cell cycle at S phase and inducing apoptosis. Importantly, compared to MTX oral administration, topical application of MTX/NIC cerosomes on imiquimod (IMQ)-induced psoriatic mouse model exhibited a superior performance in ameliorating skin lesions, reducing spleen index and epidermal thickness, and downregulating the mRNA expression levels of proinflammatory cytokines including TNFα, IL-23, IL-17A, IL-6, IL-1β, and IL-22. Taken together, MTX/NIC cerosomes is a promising approach for psoriasis topical treatment.

Evaluation of ototoxicity of intratympanic administration of Methotrexate in rats

OBJECTIVE

Methotrexate is a dihydrofolate reductase enzyme inhibitor with very high selectivity, and it is an antiproliferative folic acid antagonist used for the treatment of autoimmune diseases. In this study, our objective was to evaluate the effect of intratympanic Methotrexate application in the inner ear.

METHODS

This study was planned as an animal study. This study performed in a tertiary referral center. 24 healthy female rats were used in our study. They were separated into three groups. 0.2 cc intratympanic saline was applied to both ears of Group 1. Paracentesis was applied to the tympanic membrane in both ears of Group 2. 0.2 cc intratympanic Methotrexate was applied to both ears of Group 3. At the beginning of the study, Distortion-product otoacoustic emissions (DPOAE) and Auditory brainstem response (ABR) of all rats were measured and then again on the 5th, 10th and 15th day. Histologic examinations of all groups were compared.

RESULTS

There was not any significant difference between basal DPOAE and ABR measurement values of the groups and the results were measured again on the 5th, 10th and 15th day (p > 0.05). There was no difference between the groups in terms of histology.

CONCLUSION

The intratympanic Methotrexate injection does not have any ototoxic effect on inner ear. We assume that intratympanic Methotrexate could be used safely on inner ear diseases in which steroid treatment is contraindicated or not effective.

Fingolimod Hydrochloride Gel for Dermatological Applications: Optimization of Formulation Strength and Effect of Colloidal Oatmeal (Aveeno®) as Penetration Enhancer

Fingolimod (FNGL) is an immune-modulatory agent prescribed for relapsing forms of multiple sclerosis. Because of its mechanism of action, FNGL is potentially a treatment for chronic, non-curable T-lymphocyte-driven inflammatory skin diseases (TLDISD) such as psoriasis and atopic dermatitis. Since severe side effects limit the systemic administration of FNGL, the objective of this study is to develop a hydroxypropyl cellulose (2%) FNGL gel for dermatological applications. First, the effect of FNGL strength (0.05%, 0.10%, 0.50%, and 1.00%) on skin permeability and retention was investigated. We carried out several permeation studies with vertical Franz diffusion cells and (i) cellulose or (ii) excised dorsal porcine ear skin (EDPES) as membrane. We also quantified FNGL in the stratum corneum and in dermis with the tape-stripping method. Permeability parameters as well as the amount retained in skin increased significantly (p < 0.01) with strength; however, there was no statistically significant difference between the 0.50% and 1.00% gels for both cellulose and EDPES. Therefore, we selected the 0.50% gel to investigate the effect of colloidal oatmeal (0%, 1%, 3%, 6%, and 10%) on FNGL in vitro permeability and skin retention. Colloidal oatmeal has beneficial dermatological properties for TLDISD and may complement FNGL activity. Permeability increased significantly (p < 0.001) with colloidal oatmeal at the 6% and 10% strength with an enhancement ratio of 3.5 and 2.4, respectively, whereas the amount retained in the skin decreased significantly (p < 0.001) compared to the base gel. In conclusion, the 0.50% FNGL(.)HCL gel with 6% Aveeno® has very promising permeability characteristics for delivery of FNGL to the skin.

Subcutaneous methotrexate for symptomatic control of severe recalcitrant psoriasis: safety, efficacy, and patient acceptability

Background

Although oral methotrexate is an effective first-line traditional systemic therapy for psoriasis, the use of the subcutaneous form of methotrexate for the treatment of psoriasis has not been fully established.

Objective

This study is a literature review of the research related to the safety, efficacy, and patient acceptability of subcutaneous methotrexate for its application in the treatment of severe recalcitrant psoriasis.

Methods

Systematic literature searches were conducted of the PubMed, Ovid, and ClinicalTrials.gov databases.

Results

Only three relevant sources of literature were found studying subcutaneous methotrexate specifically in the context of psoriasis. Of these, only one clinical trial was found to directly study the use of subcutaneous methotrexate in psoriasis patients; however, results of this study have not been published. The other two literature sources involved a cost-effectiveness analysis and a literature review for subcutaneous methotrexate. Otrexup™ and Rasuvo™ are two particular single-use auto-injector modalities of subcutaneous methotrexate that are approved by the US Food and Drug Administration. The equivalents of Rasuvo available in countries outside of the USA are advertised as Metoject^® or Metex^®. Much more research has been conducted on the use of subcutaneous methotrexate in rheumatoid arthritis patients.

Conclusion

There is a lack of original evidence-based studies evaluating the use of subcutaneous methotrexate specifically for the treatment of psoriasis. Based on the more extensively researched data on the safety, efficacy, and patient acceptability of subcutaneous methotrexate in rheumatoid arthritis patients, its application for the treatment of moderate-to-severe psoriasis is promising. More evidence-based studies on psoriasis subjects are needed to explore the practical application of subcutaneous methotrexate as a treatment option for severe recalcitrant psoriasis.

Psoriasis induced by thalidomide in a patient with multiple myeloma

A 54-year-old woman developed psoriasis on the plantar surface of her feet after 2 weeks of thalidomide 100 mg daily for the treatment of multiple IgG myeloma. She did not have any previous history of psoriasis. Thalidomide was immediately stopped and topical treatment with calcipotriol ointment and β-methasone valerate was started. Psoriasis disappeared completely after 2 weeks of topical therapy. This is the first case of de novo psoriasis in a patient with multiple myeloma under treatment with thalidomide. Our observation provides further evidence of the potential paradoxical effect of thalidomide on tumour necrosis factor-α production.

Treatment of psoriasis: focus on clinic-based management with infliximab

Psoriasis is a disabling chronic inflammatory condition of the skin and joints that typically requires long-term treatment. Recommended treatments for psoriasis include a wide range of topical and systemic options, from topical agents and targeted phototherapy for mild psoriasis to traditional systemic agents such as methotrexate, cyclosporine and acitretin for more serious disease. The introduction of targeted biological agents such as T-cell-modulating agents, tumor necrosis factor α (TNFα) antagonists and interleukin (IL)-12 and IL-23 inhibitors has provided new choices for the management of psoriasis and psoriatic arthritis that may offer better long-term efficacy and tolerability than traditional approaches. Most biological agents are administered by subcutaneous injection. Infliximab, a TNFα antagonist, is the only biological agent approved for psoriasis that is administered by intravenous infusion, in the setting of hospital-based or specialized infusion center-based clinics. Infliximab allows weight-based dosing and may offer more rapid disease control than other biological agents, with significant improvements seen as early as 1 week after treatment initiation. This article gives an overview of psoriasis management, focusing on clinic-based infusion therapy with infliximab.

Management of a Dog with Poorly Regulated Diabetes Mellitus, Chronic Pancreatitis, and Suspected Atopy with Cyclosporine

A 3-year-and-9-months old male neutered Bichon Frise was presented for a second opinion for diabetes mellitus, weight loss, pruritus, and loss of hair. During further work-up, the dog was diagnosed with uncontrolled diabetes mellitus and concurrent diagnoses of pancreatitis and atopy were also suspected. Multiple adjustments of insulin therapy did not improve control of diabetes mellitus. Also, a variety of different treatments failed to improve pruritus. The dog was seen by a veterinary dermatologist who further suspected atopy and started treatment with cyclosporine. Pruritus improved and coincidentally serum Spec cPL and fructosamine concentrations normalized after therapy, suggesting the possibility that cyclosporine may have controlled pancreatic inflammation and improved control of diabetes mellitus. This case report would suggest that further research into autoimmunity in dogs with chronic pancreatitis is warranted. Also, a controlled study is needed and in progress before the use of cyclosporine in dogs with chronic pancreatitis or a subgroup thereof can be advocated.

Cytokines and anticytokines in psoriasis

BACKGROUND

Psoriasis is a chronic autoimmune hyperproliferative skin disease of varying severity affecting approximately 2-3% of the general population in the USA and Europe. Although the pathogenesis of psoriasis has not been fully elucidated, an immunologic-genetic relationship is likely. Cutaneous and systemic overexpression of various proinflammatory cytokines (TNF, interleukins, interferon-gamma) has been demonstrated in psoriatic patients.

METHODS

We reviewed the current database literature and summarized the involvement of cytokines and their receptors in the pathogenesis and treatment of psoriasis.

RESULTS

Although many cytokine/anti-cytokine therapies have been conducted, TNF antagonists in the treatment of both psoriasis arthropatica and vulgaris appear to be the most widely used clinically. Interestingly, the efficacy and tolerability of some cytokines (rhIL-11 or ABX-IL-8,) were found to be much lower than expected.

CONCLUSIONS

Preliminary results obtained with cytokine and anti-cytokine therapies appear promising and as such continued research is clearly indicated.

Immunobiologics in the treatment of psoriasis

The pathogenesis of various inflammatory cutaneous diseases such as psoriasis, atopic dermatitis and mycosis fungoides relies greatly on the abnormal function of T cells. Fundamental knowledge of the role of T cells in the cutaneous immune response has led to the development and production of biologic molecules designed to block T cell function at various steps, specifically activation (i.e. alefacept, efalizumab), trafficking into inflamed skin (i.e. efalizumab) and effector function under cytokine control (i.e. etanercept, infliximab, adalimumab, and anti-IL-12 antibody). We review the immune abnormalities and the role of T cells in psoriasis, and the recent biologic therapies, which share the common mission to hinder T cell activity in inflammatory diseases. An advantage from the preciseness of these biologic therapies is the potential limit of non-specific and potentially devastating organ toxicity, which commonly plagues other systemic therapies.

Incidence of infection during efalizumab therapy for psoriasis: analysis of the clinical trial experience

BACKGROUND

Because many therapies for psoriasis disrupt the normal inflammatory cascade and could theoretically impair the body's ability to respond to external pathogens, a possible increase in the incidence of infection is a concern with any new psoriasis therapy that affects the immune system. Efalizumab is a biologic therapy targeted to inhibit T cells. Its efficacy has been shown in clinical trials encompassing >3500 patients with psoriasis.

OBJECTIVES

The aims of this article were to review the incidence of infection observed in efalizumab-treated patients during 12-week, Phase III clinical trials, compare the incidence rate with that in patients receiving placebo, and evaluate the incidence of infection observed in patients with extended (>12-week) efalizumab use.

METHODS

Adverse events (AEs) of infection were tabulated from a pooled data set of 2335 patients enrolled to receive 12 weeks of subcutaneous (SC) efalizumab 1 or 2 mg/kg . wk or placebo in 4 randomized, double-blind, placebo-controlled, Phase III efalizumab clinical studies. The incidence of infection was further evaluated using pooled data from 1115 patients who received up to 24 weeks of efalizumab therapy during 5 clinical trials with treatment extension arms and from 170 patients who received up to 108 weeks (27 months) of continuous therapy in an open-label, Phase III efalizumab trial of 36 months' total duration.

RESULTS

The incidence and severity of AEs of infection during 12 weeks of efalizumab therapy were comparable to those observed in patients receiving placebo (overall, 28.6% vs 26.3%). Infections did not appear to increase with extended therapy of up to 27 months. Serious infections requiring hospitalization occurred in 1.1% of efalizumab-treated patients.

CONCLUSION

The present review of the available Phase III clinical trial suggests that efalizumab is not associated with an increased risk for infection in patients receiving initial or long-term (27-month) treatment for moderate to severe chronic plaque psoriasis.

Identification of avarol derivatives as potential antipsoriatic drugs using an in vitro model for keratinocyte growth and differentiation

Avarol, a marine sesquiterpenoid hydroquinone, and 14 avarol derivatives have shown interesting anti-inflammatory properties in previous studies. In this study, avarol and derivatives were evaluated in high-throughput keratinocyte culture models using cytokeratin 10 and SKALP/Elafin expression as markers for respectively normal and psoriatic differentiation. Avarol and five of its derivatives (5, 10, 13, 14 and 15) were selected for further study. Only 10, 13, 14 and 15 were able to inhibit keratinocyte cell growth. Changes in expression levels of 22 genes were assessed by quantitative real time PCR (qPCR). From these genes, TNFalpha mRNA levels showed the strongest changes. For compound 13, 15 and dithranol (used as a model antipsoriatic drug), a dose-dependent downregulation of TNFalpha mRNA was found. The changes in TNFalpha mRNA were confirmed at the protein level for compound 13. Additionally, this compound was able to reduce also IL-8 and COX-2 mRNA levels and this effect was correlated with a reduction in COX-2 protein expression. The mechanism of action of this compound involves at least the inhibition of NF-kappaB-DNA binding activity. In conclusion, our high-throughput screening models in combination with quantitative assessment of changes in gene expression profiles identified the avarol derivative 13, a benzylamine derivative of avarol at the 4' position of benzoquinone ring, as an interesting anti-psoriatic drug candidate that inhibits keratinocyte cell growth and TNFalpha and COX-2 expression.

Altered keratin 17 peptide ligands inhibit in vitro proliferation of keratinocytes and T cells isolated from patients with psoriasis

BACKGROUND

Identification of critical autoantigenic T-cell epitopes is key to developing antigen-based therapies for autoimmune diseases, including psoriasis. Our previous work demonstrated that 3 peptides on keratin 17 are able to stimulate peripheral blood lymphocytes of HLA-DRB1*07-positive patients with psoriasis and to serve as immunodominant T-cell epitopes.

OBJECTIVE

We sought to determine antagonistic altered peptide ligands to psoriatic T cells with a down-modulatory effect in inhibiting keratinocyte proliferation.

METHODS

Psoriatic altered peptide ligands were generated by single alanine residue substitutions at a critical T-cell receptor contact residue position. Antagonistic altered peptide ligands were identified by suppression screening of psoriatic T-cell activation and keratinocyte proliferation.

RESULTS

Altered peptide ligands 119R and 355L can inhibit psoriatic T-cell activation more effectively than other altered peptide ligands, especially 355L, with inhibition of T-cell proliferation and the secretion of interferon gamma and interleukin 2 in parallel with the up-regulation of interleukins 4 and 10 as well as transforming growth factor-beta. In coincubation assay, altered peptide ligands 119R and 355L can down-regulate the function of psoriatic T cells more effectively than wild-type epitopes solely, but less effectively than altered peptide ligands solely. In prepulse assay altered peptide ligand 119R can down-regulate the activation of psoriatic T cells more effectively than in coincubation but less effectively as compared with altered peptide ligand 119R only. Altered peptide ligand 355L was also shown to have a similar presentation. T-cell culture supernatants (1:100) from the concentrations (10 microg.mL(-1) and 100 microg.mL(-1) with 119R, 100 microg.mL(-1) with 355L) were more effective than the other ratios in inhibiting keratinocyte proliferation.

LIMITATIONS

This study had a relatively small sample size (52 patients and 48 healthy controls).

CONCLUSION

Our findings show that the altered peptide ligands 119R (VAALEEANTELEVKI) and 355L (ENRYCVQASQIQGLI) are capable of inhibiting proliferative responses of psoriatic T cells and keratinocyte proliferation in vitro, at least, with enhanced helper T cell type 2 polarization. Thus, to our knowledge, this article is the first report of the demonstration of therapeutic activity of altered peptide ligands derived from keratin 17.

Inhibition of the nuclear factor-kappaB signaling pathway by leflunomide or triptolide also inhibits the anthralin-induced inflammatory response but does not affect keratinocyte growth inhibition

We performed this study to determine the relationship between activation of nuclear factor (NF)-kappaB and inhibition of keratinocyte growth by anthralin, which not only might be useful for a better understanding of the role of NF-kappaB in the pathogenesis of psoriasis, but also indicate whether the inflammatory reaction induced by anthralin is inseparable from its antipsoriatic activity. The involvement of NF-kappaB was assessed using the antipsoriatic drugs leflunomide and triptolide (T0) as effectors, since they can inhibit NF-kappaB activation induced by anthralin. The results showed that the inhibition of keratinocyte growth by anthralin was not related to the activation of NF-kappaB. Using sodium salicylate, a known NF-kappaB inhibitor, further confirmed this conclusion. Thus it might be possible to inhibit the inflammatory response induced by anthralin via repression of NF-kappaB activation. We found that leflunomide or T0 could significantly inhibit the mRNA overexpression of interleukin-8 and intercellular adhesion molecule-1 in keratinocytes induced by anthralin. Taken together, our data indicate that the growth inhibition of anthralin is related to the NF-kappaB-independent signaling pathway, and that leflunomide or T0 could control proinflammatory cytokine expression induced by anthralin via inhibiting the activation of NF-kappaB.

Analysis of p53 tumor suppressor gene, H-ras protooncogene and proliferating cell nuclear antigen (PCNA) in squamous cell carcinomas of HRA/Skh mice following exposure to 8-methoxypsoralen (8-MOP) and UVA radiation (PUVA therapy)

Treatment with 8-methoxypsoralen (8-MOP) and ultraviolet radiation (primarily UVA), called PUVA therapy, has been used to treat different chronic skin diseases but led to a significant increased risk for skin cancer. The National Toxicology Program (NTP) performed a study in mice treated with PUVA that showed a significant increase in squamous cell carcinomas of the skin. In the present study, we evaluated the protein expression of p53 and PCNA and DNA mutations of p53 and H-ras genes in both hyperplastic and neoplastic squamous cell lesions from the NTP study. By immunohistochemical staining, protein expression of both p53 and PCNA was detected in 3/16 (19%) of hyperplastic lesions and 14/17 (82%) of SCCs in groups treated with both 8-MOP and UVA. The mutation frequency of p53 in SCCs from mice administered 8-MOP plus UVA was 15/17 (88%) with a predominant distribution of mutations in exon 6 (14/15 - 93%). No H-ras mutations were detected in the hyperplastic lesions/tumors. The mutagenic effect of PUVA on the p53 tumor suppressor gene may lead to a conformational modification and inactivation of the p53 protein, which are considered critical steps in PUVA-induced skin carcinogenesis. The p53 mutational frequency and patterns from our study were different from those reported in human PUVA-type tumors.

Emerging drugs for moderate-to-severe psoriasis

Psoriasis is a chronic, incurable, disabling skin disease characterised by red, scaly plaques. Approximately 23% of psoriasis patients also have an accompanying arthritis that can become debilitating. Psoriasis has a stigmatising effect on its victims, who often feel socially isolated. Although the exact aetiology of psoriasis is still unknown, it is clearly an immune-mediated disease. Traditional therapies for psoriasis include topical drugs, such as corticosteroids, retinoids and vitamin D3 analogues; systemic drugs, such as methotrexate, ciclosporin and retinoids; and phototherapy. These mainstays of treatment are efficacious for the treatment of severe disease; however, most are associated with toxicities or are inconvenient. Recent advances in biotechnology have produced new pharmaceuticals that interfere with immune responses thought to be involved in the pathogenesis of psoriasis and other inflammatory diseases. The immunobiologicals, one new family of drugs, consist of monoclonal antibodies and fusion proteins. Many have demonstrated efficacy in treating psoriasis. Some appear to offer safety benefits over traditional therapies; further monitoring and surveillance of these agents is required to adequately establish safety profiles. This article discusses existing and emerging treatments for moderate-to-severe psoriasis.

Infliximab induction therapy for patients with severe plaque-type psoriasis: a randomized, double-blind, placebo-controlled trial

BACKGROUND

Tumor necrosis factor-alpha is a key mediator in the pathogenesis of psoriasis. Infliximab is a monoclonal antibody that specifically binds to tumor necrosis factor-alpha, blocking its biologic activity.

OBJECTIVE

The purpose of this study was to access the efficacy and safety of infliximab induction therapy for patients with severe plaque psoriasis.

METHODS

In this multicenter, double-blind, placebo-controlled trial, 249 patients with severe plaque psoriasis were randomly assigned to receive intravenous infusions of either 3 or 5 mg/kg of infliximab or placebo given at weeks 0, 2, and 6. The primary end point was the proportion of patients who achieved at least 75% improvement in Psoriasis Area and Severity Index score from baseline at week 10. At week 26, patients whose Physician Global Assessment indicated moderate or severe disease were eligible for a single intravenous infusion of their assigned treatment to assess the safety of retreatment after a 20-week, treatment-free interval.

RESULTS

At week 10, 72% of patients treated with infliximab (3 mg/kg) and 88% of patients treated with infliximab (5 mg/kg) achieved a 75% or greater improvement from baseline in Psoriasis Area and Severity Index score compared with 6% of patients treated with placebo (P <.001). Improvement was observed in both infliximab groups as early as 2 weeks. Overall, 63%, 78%, and 79% of patients in the placebo, 3-, and 5-mg/kg groups, respectively, reported one or more adverse events.

CONCLUSIONS

Infliximab treatment resulted in a rapid and significant improvement in the signs and symptoms of psoriasis. Infliximab was generally well tolerated.

HLA DR B1*04, *07-restricted epitopes on Keratin 17 for autoreactive T cells in psoriasis

BACKGROUND

Psoriasis is a T cell-mediated inflammatory skin disease. Recent evidence suggests that activated CD4+ helper T lymphocytes of the Th1 phenotype play an important role in the pathogenesis of the disease. For psoriatic autoreactive T cells, Keratin 17 is a major target antigen and an epitope containing ALEEAN sequence has been described, but other psoriasis-related epitopes are still unknown.

OBJECTIVE

To identify the HLA DR B1*04, *07-restricted T cell epitopes on Keratin 17.

METHODS

HLA DRB1*04, *07-restricted T cell epitope regions on Keratin 17 were predicted based on related software and internet servers. Keratin 17 gene was amplified from psoriatic epidermis and the proteins of the predicted epitope regions were expressed, identified and purified. T cells from psoriatic patients reacted in cultivation with peptide-major histocompatibility complex (p-MHC) compound, then the level of cell proliferation and the concentration of interferon-gamma in culture supernatant were detected. After the psoriasis-related epitope regions were narrowed down, the epitopes on them were predicted further. These epitopes were then expressed and validated by T cell response in vitro.

RESULTS

Four epitopes--S1 (118-132), S2 (169-183), S4 (323-337) and S4 (348-362) can stimulate the proliferation and interferon-gamma production of psoriatic T cells more effectively than other epitopes (p<0.01) and react weakly with the T cells from healthy volunteers (p>0.05).

CONCLUSION

Epitopes S1 (118-132), S2 (169-183), S4 (323-337) and S4 (348-362) are immunodominant DR B1-restricted T cell epitopes for psoriasis. Among them, S1 (118-132) contains the ALEEAN sequence while the others with different amino acid sequence have not been reported before. Further studies based on these peptides would provide a more complete understanding of the immunological basis of psoriasis.

Overview of biologic agents in medicine and dermatology

Three agents have recently been approved by the Food and Drug Administration for the treatment of chronic plaque psoriasis: alefacept, efalizumab, and etanercept. The field of dermatology has now entered a new era, joining other disciplines of medicine that have been using biologic agents for decades. These new therapies offer psoriatic patients the potential for safe and effective long-term management of this disease. This article reviews how an increased understanding of the pathophysiology of psoriasis led to the development of these products.

Novel pharmacological approaches in the treatment of psoriasis

Progress in the understanding of psoriasis as a T-cell mediated inflammatory disease has led to the development of new immunomodulatory therapies. Currently the main focus is on the so-called biologics (or biological agents), including fusion proteins, monoclonal antibodies, cytokines and selective receptors. They mainly target single steps in the complex cascade of humoral and cellular inflammatory immuno-mechanisms that finally lead to the accelerated growth of epidermal and vascular cells in the psoriatic lesions. The most promising and advanced biological agents are discussed along with their influence on the critical pathophysiological steps in psoriasis, including depletion of T cells, blockade of initial T-cell activation and T-cell receptor (TCR) stimulation, blockade of costimulatory signals and T-cell proliferative signals as well as restoration of the T helper type 1 (Th1)/Th2 balance by diminishing type 1 cytokines and administration of type 2 cytokines. In addition to the biological agents, further development of 'classical' dermatological therapies, such as retinoids, or the discovery of new indications for non-dermatological agents contribute to the novel pharmacological approaches in the treatment of psoriasis.

Tratamento sistêmico da psoríase - Parte I: metotrexato e acitretina

Embora a fisiopatologia da psoríase ainda não esteja totalmente esclarecida e permaneçam dúvidas quanto à natureza dos antígenos que levam à ativação do linfócito T e quanto ao papel dos mecanismos reguladores dos surtos e da resolução da inflamação, são inegáveis os avanços terapêuticos das últimas décadas. Além do surgimento de novos medicamentos, a melhor utilização de tratamentos clássicos e a valorização do impacto da terapêutica na qualidade de vida dos pacientes têm contribuído para a diminuição dos índices de morbidade da doença. Este artigo de EMC-D aborda a utilização de metotrexato e acitretina no tratamento da psoríase. A utilização de outros imunomoduladores e de terapias biológicas será objeto de próximo capítulo.

Systemic therapies for psoriasis: understanding current and newly emerging therapies

The treatment of moderate to severe psoriasis is a rapidly expanding area. Recent insights into the pathogenesis of this disease as a T-cell mediated process has led to a greater understanding of the mechanisms of action of conventional FDA-approved systemic therapies such as methotrexate, cyclosporine, acitretin, and psoralen with ultraviolet A phototherapy. It has also led to the development of rationally targeted therapies against key components of the immune process critical in the generation of the psoriatic plaque. Safety and efficacy data from clinical studies of 4 biologic agents furthest along in their development are reviewed. These results are promising, adding to the armamentarium for treating this disease.

Nicotinamide: a potential addition to the anti-psoriatic weaponry

Psoriasis is an inflammatory disorder characterized by a T helper type 1 cell cytokine pattern. Increased expression of adhesion molecules, prominent neutrophil accumulation, and increased production of nitric oxide are characteristics of this disorder. Moreover, histamine and proteases are supposed to participate in the pathogenesis of psoriasis. Nicotinamide is an inhibitor of poly (ADP-ribose) polymerase-1 (PARP-1) that, through enhancement of nuclear kappa B-mediated transcription, plays a pivotal role in the expression of inflammatory cytokines, chemokines, adhesion molecules, and inflammatory mediators. Through interaction with CD38 and inhibition of IL-1, IL-12, and TNF-alpha production, nicotinamide produces a mild TH2 bias. Nicotinamide is a potent phosphodiesterase inhibitor and suppresses neutrophil chemotaxis and mast cell histamine release. It inhibits nitric oxide synthase mRNA induction and suppresses antigen-induced lymphocyte transformation. Nicotinamide increases the biosynthesis of ceramides, which upon degradation produce sphingosine. Sphingosine inhibits protein kinase C (PKC) and decreases basal cell proliferation dependent on PKC. Taken together, it can be reasoned that nicotinamide could be a useful addition to anti-psoriatic armamentarium. The combination of nicotinamide and thalidomide or methotrexate provided a powerful synergistic inhibition of murine collagen-induced arthritis. Nicotinamide decreased the methotrexate-induced hepatotoxicity. The above combinations may prove to have a powerful anti-psoriatic effect as well. As PARP inhibitors could exert anti-retroviral effect, nicotinamide could also be of special value in the treatment of HIV-infected psoriatics.

Genetic basis of psoriasis vulgaris and its pharmacogenetic potential

Psoriasis vulgaris is one of the most prevalent T cell-mediated inflammatory diseases in humans. It is multifactorial in origin and shows polygenic inheritance. Systemic immunosuppressive therapies play an important role in management of severe disease cases but are associated with variable response and toxicity. Within the last decade there have been significant advances in our understanding of the genetic basis of this complex disease and polymorphic candidate genes have been proposed. Susceptibility gene characterization together with an explosion in knowledge of its primary immune basis will further define disease pathways involved in psoriasis pathogenesis. This holds the promise of rational design of new therapeutic agents and pharmacogenetic testing to predict responders from non-responders and those at risk of toxicity.