Pimecrolimus inhibits up-regulation of OX40 and synthesis of inflammatory cytokines upon secondary T cell activation by allogeneic dendritic cells

Ovalicin attenuates atopic dermatitis symptoms by inhibiting IL-31 signaling and intracellular calcium influx

Atopic dermatitis (AD) is a common skin disorder difficult to be treated with medication. This study investigated the potential of ovalicin extracted from Cordyceps militaris for the treatment of AD using in vitro and in vivo models. We found that, in canine macrophage cell line DH82, lipopolysaccharide (LPS) upregulated the expression of genes associated with inflammation and pruritic responses through activating calcium and interleukin-31 (IL-31) signaling, and the upregulation could be suppressed by ovalicin, with an effect significantly stronger than dexamethasone. Ovalicin also reduced the expression of IL-31 downstream genes, including JAK2 (Janus kinase 2), TRPV1 (transient receptor potential vanilloid receptor-1), and HRH2 (histamine receptor H2). Ovalicin significantly alleviated the allergic symptoms in the AD mouse model. Histologically, the number of macrophages and mast cells infiltrated in the dermis was significantly reduced by ovalicin treatment. In the skin tissue of AD mice, reduction of IL-31 receptor was observed in the ovalicin treated group compared to the group without ovalicin treatment. To our knowledge, this is the first study to elucidate the anti-atopic mechanism of ovalicin, which could be an alternative to steroidal drugs commonly used for AD treatment.

The chronicity of tonsillitis is significantly correlated with an increase in an LTi cell portion

The current study explored the relationship between lymphoid tissue inducer (LTi) cells and patients' clinical and immunological status. LTi cells are critical for lymphoid tissue development and maintenance of CD4 T cell-dependent immune responses. The percentage of CD117+CD3-CD56-CD127+ RORγ+ LTi cells isolated from human tonsils was determined and correlated with changes in other immune subsets and clinical factors. We found that the portion of LTi and CD4 T cells was significantly increased in chronic tonsillitis compared to non-inflamed tonsils. Additionally, the expression of OX40 by memory CD4 T cells and OX40 ligand (OX40L) and interleukin (IL)-22 by LTi cells was higher in chronically inflamed tonsils. The treatment for tonsillitis with ibuprofen did not alter LTi cell viability and the expression of OX40L and IL-22. These results demonstrate that during chronic inflammation, LTi cells are increased and express higher levels of OX40L and IL-22, and this is correlated with an increase in memory CD4 T cells.

Topical therapies for pruritus

Itch, or pruritus, is the predominant symptom associated with acute and chronic cutaneous disease, and in some cases may be debilitating. To date, there is no single universally effective anti-itch treatment. Because the pathophysiology of itch in most cutaneous or systemic disorders remains unclear, antipruritic therapy is often directed against a variety of targets, including the epidermal barrier, immune system, or the nervous system. Topical therapy is the mainstay of dermatologic management of acute or localized itch or in patients with contraindications to systemic therapies. This review will summarize current topical therapies to treat pruritus and discuss potential future therapies.

What's new in atopic eczema?

IMPORTANCE OF THE FIELD

Atopic eczema (AE) is a chronic relapsing inflammatory skin condition and one of the most common, potentially debilitating diseases with increasing incidence.

AREAS COVERED IN THIS REVIEW

The complex etiology of AE with multiple systemic and local immunologic and inflammatory responses and interactions between susceptibility genes and environmental factors leading to defects in skin barrier function and eczematous skin lesions is presented. Knowledge of pathogenesis is important for understanding the more innovative treatment approaches discussed.

WHAT THE READER WILL GAIN

Basic therapy consists of hydrating topical treatment and avoidance of specific and unspecific provocation factors. For acute eczematous skin lesions, anti-inflammatory treatment consists mainly of topical glucocorticoids and topical calcineurin inhibitors (tacrolimus and pimecrolimus). Microbial colonization and superinfection may induce skin exacerbation, which can be treated by either topical or systemic antimicrobial treatment. Systemic anti-inflammatory therapy is limited to severe cases and consists of systemic steroids, cyclosporine A or mycophenolate mofetil. Novel anti-inflammatory concepts that go beyond corticosteroids are in the early phases of development. There are targeted therapeutic approaches, such as cytokine and chemokine modulators and it remains to be investigated how effective they will be and what side effects they may carry.

TAKE HOME MESSAGE

Existing treatment modalities such as barrier repair therapy, topical immunosuppressive agents, antiseptic treatment as well as systemic treatment options are discussed. The review aims to summarize the most recent findings of more innovative treatment approaches such as modulation of cytokines or chemokines, modulation of T-cell responses or anti-IgE therapy.

Topical pimecrolimus: a review of its use in the management of pediatric atopic dermatitis

Topical pimecrolimus 1% cream (Elidel) [hereafter referred to as topical pimecrolimus] is a nonsteroidal alternative in the treatment of pediatric atopic dermatitis. In vehicle-controlled, short-term, continuous-use trials in pediatric patients with mild to moderate atopic dermatitis, topical pimecrolimus was effective in treating disease symptoms. Topical pimecrolimus was effective in preventing disease flares and reducing the need for topical corticosteroids in longer term, intermittent-use trials. In addition, topical pimecrolimus was associated with improvements in the health-related quality of life (HR-QOL) of pediatric patients with atopic dermatitis and their parents. In vehicle-controlled trials, topical pimecrolimus was generally as well tolerated as vehicle. Topical pimecrolimus showed similar efficacy to topical tacrolimus 0.03% ointment (hereafter topical tacrolimus) in a short-term, continuous-use trial and the two agents had a generally similar tolerability profile. Although comparative data between topical pimecrolimus and topical corticosteroids are lacking in pediatric patients, and the long-term tolerability (beyond 1-2 years) of topical pimecrolimus is yet to be established, topical pimecrolimus is a useful agent in the management of pediatric patients with mild to moderate atopic dermatitis who do not achieve satisfactory treatment with other topical pharmacologic treatments, including topical corticosteroids.

Clinical evaluation of pimecrolimus eye drops for treatment of canine keratoconjunctivitis sicca: a comparison with cyclosporine A

The aim of this study was to evaluate the efficacy of pimecrolimus oil-based eye drops in alleviating the clinical signs of keratoconjunctivitis sicca (KCS) in dogs and to compare the efficacy with that of cyclosporine A (CsA) ointment. An open-label, multicenter study enrolling 44 dogs previously untreated with CsA was conducted. Dogs were randomly assigned to a treatment group and medicated twice daily for 8 weeks. After that time the mean increase (+/-SEM) in the Schirmer tear test was 9.2+/-1.6 mm/min in the pimecrolimus group and 5.8+/-1.1 mm/min in the CsA group (P=0.085). The improvement in clinical signs of inflammation in eyes treated with pimecrolimus was significantly greater than in eyes treated with CsA (P=0.02). The results show that 1% pimecrolimus oily eye drops are as safe as and more effective than CsA ointment in controlling KCS in dogs.

Discovery of Topical Calcineurin Inhibitors and Pharmacological Profile of Pimecrolimus

Using a newly developed model of allergic contact dermatitis in pigs, calcineurin inhibitors of the tacrolimus and ascomycin type were shown to have a highly anti-inflammatory action after topical application. These findings provided the first pharmacological evidence of the efficacy of this novel class of topical agents in the treatment of inflammatory skin diseases, and, thus, their potential to become the first alternative to corticosteroids in more than 40 years. As a result of a large research program into ascomycins, pimecrolimus (Elidel(R), SDZ ASM 981) was selected for development due to its favorable pharmacology and safety profile, alongside tacrolimus (Protopic(R), FK 506). In vitro, pimecrolimus inhibits the transcription and release of pro-inflammatory cytokines in T cells. Similar to the corticosteroids, betamethasone-17-valerate and dexamethasone, pimecrolimus is effective at nanomolar concentrations. Targeting mainly T cells, pimecrolimus has, however, a more specific mode of action. Moreover, in contrast to corticosteroids, pimecrolimus has no effect on Langerhans' cells, the professional antigen- presenting dendritic cells of the skin that are crucial for local immunosurveillance. When applied topically, pimecrolimus exerts a high and selective anti-inflammatory activity in the skin, shows minimal percutaneous absorption, and has a low potential to affect systemic immunoreactions. Pimecrolimus cream 1% has proven to be well tolerated, safe, and highly effective in clinical studies in patients with atopic dermatitis.

Pimecrolimus and tacrolimus differ in their inhibition of lymphocyte activation during the sensitization phase of contact hypersensitivity

BACKGROUND

As reported previously, oral administration of the calcineurin inhibitors (CNI) pimecrolimus and tacrolimus resulted in equipotent inhibition of the elicitation phase of contact hypersensitivity (CHS) in mice. The sensitization phase was inhibited by tacrolimus but was unaffected by pimecrolimus, even at higher doses.

OBJECTIVE

The kinetics of lymph node hyperplasia and up-regulation of T and B cell activation antigens were analyzed to obtain a better understanding of the divergent CNI profile in CHS.

METHODS

Lymph node (LN) cells of CNI-untreated and treated mice were examined with flow cytometry at various time points after sensitization with oxazolone. LN hyperplasia and drug levels were also determined.

RESULTS

Sensitization induced a higher portion of LN cells expressing the activation antigens CD25, CD69 and CD134 and an increase in activated B cells (B220(+)/CD40(+)) compared to naïve mice. Up-regulation of these markers was completely or profoundly blocked with tacrolimus, whereas pimecrolimus at the three-fold higher dose caused significantly less inhibition. Tacrolimus also completely blocked the sensitization-associated increase of CD11c(+) antigen presenting cells (APC) in LN, whereas pimecrolimus showed significantly less inhibition. In contrast to tacrolimus, LN weight and cellularity were not affected by pimecrolimus at any time point after sensitization. Concentration of tacrolimus in blood and in the draining LN substantially exceeded that of pimecrolimus by factors 6.7-14 and 5.6-5.8, respectively, at the same dose levels.

CONCLUSION

In contrast to tacrolimus, systemic treatment of mice with pimecrolimus only weakly interferes with lymphocyte activation and does not affect hyperplasia of the draining lymph nodes during sensitization.

Onset of pruritus relief with pimecrolimus cream 1% in adult patients with atopic dermatitis: a randomized trial

BACKGROUND

Pimecrolimus cream 1% (Elidel, Novartis Pharmaceuticals AG) effectively improves/relieves pruritus associated with atopic dermatitis (AD), but few data are available regarding the timing of relief. The purpose of this study was to investigate the timing of pruritus relief produced with pimecrolimus in adults with mild/moderate AD and moderate/severe pruritus.

METHODS

Patients were randomized to 7 days of treatment with pimecrolimus (n = 100) or vehicle (n = 98). Pruritus severity was assessed daily on a 4-point scale (0 = absent, 3 = severe), reflecting the previous 24 h experience. Patients who completed this core study were eligible to enter a voluntary 5-week, open-label extension study.

RESULTS

A significant effect was noted within 48 h of treatment, with pruritus improving in 56% of pimecrolimus-treated patients and 34% of vehicle-treated patients (P = 0.003). Pruritus relief was maintained during the remainder of the core and extension phases, and was accompanied by an improvement in the Investigator's Global Assessment score.

CONCLUSION

Pimecrolimus cream 1% significantly reduced pruritus within 48 h.

Immunomodulation and safety of topical calcineurin inhibitors for the treatment of atopic dermatitis

Atopic dermatitis (AD) is a chronic or chronically relapsing inflammatory skin condition that primarily affects children. Topical corticosteroids have been the mainstay of treatment since the late 1950s. While providing excellent short-term efficacy, topical corticosteroid usage is limited by potential adverse effects, including impairment of the function and viability of Langerhans cells/dendritic cells. The recently introduced topical calcineurin inhibitors pimecrolimus cream 1% (Elidel) and tacrolimus ointment 0.03 and 0.1% (Protopic) exhibit a more selective mechanism of action and do not affect Langerhans cells/dendritic cells. For the immune system of young children 'learning' to mount a balanced Th1/Th2 response, this selective effect has particular benefits. In clinical experience, topical calcineurin inhibitors have been shown to be a safe and effective alternative to topical corticosteroids in almost 7 million patients (>5 million on pimecrolimus; >1.7 million on tacrolimus). Topical pimecrolimus is primarily used in children with mild and moderate AD, whereas tacrolimus is used preferentially in more severe cases. None of the topical calcineurin inhibitors have been associated with systemic immunosuppression-related malignancies known to occur following long-term sustained systemic immunosuppression with oral immunosuppressants (e.g., tacrolimus, cyclosporine A, and corticosteroids) in transplant patients. Preclinical and clinical data suggest a greater skin selectivity and larger safety margin for topical pimecrolimus.

Pimecrolimus 1% cream for the treatment of discoid lupus erythematosus

OBJECTIVES

To determine the safety and efficacy of pimecrolimus cream on lesions of discoid lupus erythematosus.

METHODS

In an open-label phase II trial, patients with discoid lupus were treated with pimecrolimus 1% cream twice daily for 8 weeks. We assessed skin involvement with a clinical severity score, quality of life, patient improvement and toxicity. The changes were documented by skin biopsy at baseline and at the end of treatment.

RESULTS

Ten patients with a mean age of 34 +/- 17 yr and disease duration of 3 yr (range 1-8) were studied; 90% were female and 40% had received prior topical or systemic therapy without response. In all patients, improvement of skin damage was observed after therapy. A significant decrease of 52% was observed in the mean +/- s.d. clinical severity score, from 6.1 +/- 1.4 before treatment to 2.9 +/- 1.5 after treatment (P = 0.005). Quality of life score (0 = no effect, 100 = maximum effect on quality of life) showed a mean improvement of 46%, from 42.8 +/- 23.1 before to 23 +/- 16.5 after treatment (P = 0.008). According to the patients' assessment of the response to treatment, 50% qualified as marked improvement, 40% moderate and 10% slight improvement. The treatment was well tolerated; adverse reactions consisted of minimal erythema and pruritus, which resolved without any further action.

CONCLUSIONS

Our data suggest that pimecrolimus cream for discoid lupus erythematosus seems to be a safe and clinically effective option. However, this was an open and uncontrolled study, and double-blind, placebo-controlled studies are needed.

Inflammatory cell numbers and cytokine expression in atopic dermatitis after topical pimecrolimus treatment

BACKGROUND

In several clinical trials the topical application of pimecrolimus was shown to be effective in the treatment of atopic dermatitis (AD). By targeting calcineurin-dependent signaling pathways, pimecrolimus controls cytokine gene expression. The purpose of this study was to investigate the effect of pimecrolimus on the inflammatory infiltrate and cytokine expression pattern in AD upon topical therapy.

METHODS

From 10 patients with acute AD, skin biopsies as well as immunophenotype and cytokine production of peripheral blood mononuclear cells (PBMC) were examined before and 3 weeks after therapy.

RESULTS

The clinical improvement was associated with a marked regression of histopathological features. In particular, the density of the inflammatory infiltrate mostly containing lymphocytes and eosinophils declined. By double immunofluorescent staining, a reduced expression of the T helper (Th) 2 cytokines interleukin (IL)-5, IL-10, and IL-13 in both CD4+ and CD8+ T cells was demonstrated after therapy. Pimecrolimus therapy was also associated with a reduced expression of the Th1 cytokine interferon (IFN)-gamma. Interestingly, the numbers of epidermal CD1a+ dendritic cells increased following treatment. In the peripheral blood, a decrease of lymphocytes and eosinophils was noticed, but the distribution of lymphocyte subpopulations and their capacity of cytokine production did not change.

CONCLUSIONS

Topical pimecrolimus exhibits anti-inflammatory effects in AD by reducing the inflammatory cell infiltrate and cytokine expression in the dermis.

Pimecrolimus for the treatment of inflammatory skin disease

Pimecrolimus (SDZ ASM 981, Elidel ) is an ascomycin macrolactam derivative and a cell-selective inhibitor of inflammatory cytokines specifically developed to treat inflammatory skin diseases. Pimecrolimus combines high anti-inflammatory activity in the skin with a low potential to impair systemic immune reactions. Multi-centre studies have proved the efficacy and safety of pimecrolimus cream in patients with atopic dermatitis (AD) and confirmed that it is suitable for short-term treatment and long-term management of AD in adults, children and infants as young as 3 months. Topical application in humans is not associated with the atrophogenic side effects observed with corticosteroids. Pimecrolimus blood levels remained consistently low after repeated topical application and no clinically relevant drug-related systemic adverse events have been reported among the 8000 patients treated in clinical trials so far. Short-term, Phase I/II and Phase II trials of pimecrolimus administered orally in psoriasis and AD have shown that this drug is highly effective in a dose-dependent manner in patients with these diseases and has high safety profile. This finding is confirmed by pharmacogenomic blood analysis. Available data thus indicates that pimecrolimus, in both the cream and oral formulations, may represent a new option for the treatment of inflammatory skin diseases.

The effect of topical pimecrolimus on keratoconjunctivitis sicca and chronic superficial keratitis in dogs: results from an exploratory study

OBJECTIVE

Pimecrolimus is an ascomycin derivative that interferes selectively with the activation of T cells and mast cells and inhibits the production of inflammatory cytokines. This study evaluated the efficacy of an experimental ophthalmic formulation of pimecrolimus in treating keratoconjunctivitis sicca (KCS) and chronic superficial keratitis (CSK) in dogs. ANIMALS AND PROCEDURES: Eight dogs with KCS and six with CSK were included. The dogs were of various breeds, suffered from chronic conditions, and had been pretreated unsuccessfully. The affected eyes were treated with 1 drop of an experimental, corn oil-based pimecrolimus 1% formulation three times a day. Parameters evaluated included Schirmer tear test (STT), ocular discharge, conjunctival inflammation, corneal inflammatory cell infiltrate and scarring, and comfort level.

RESULTS

The effect of pimecrolimus 1% was pronounced (increase in STT values to higher than 4 mm/min, no signs of inflammation) or moderate (increase in STT values of 3-4 mm/min, mild signs of corneal/conjunctival inflammation) in a total of 6/8 animals with KCS. In 4/6 animals with CSK, the effect was either pronounced (total regression of fibrovascular infiltration into the cornea, no corneal scarring) or moderate (distinct regression of pannus, mild corneal scarring). The response to treatment was unsatisfactory in four of 14 animals.

CONCLUSION

Results of this exploratory study suggest that topical 1% pimecrolimus may be a new effective treatment for keratoconjunctivitis sicca and chronic superficial keratitis in dogs.

Pimecrolimus - an anti-inflammatory drug targeting the skin

Pimecrolimus is the most recent member of calcineurin inhibitors available for the therapy for inflammatory skin diseases. It targets T-cells and mast cells and inhibits the production and release of cytokines and other inflammatory mediators, as well as the expression of signals essential for the activation of inflammatory T-lymphocytes. Pimecrolimus has a cell-selective mode of action. In contrast to corticosteroids, it does not affect, e.g., Langerhans'cells/dendritic cells (LC/DC), as demonstrated in vitro with human monocyte-derived DC and in vivo with epidermal LC in mice, nor human primary fibroblasts. As shown in vitro with human skin and by comparison of clinical pharmacokinetic data from patients with atopic dermatitis, pimecrolimus permeates less through skin than tacrolimus and much less than corticosteroids. It, thus, has a lower potential for transcutaneous resorption after topical administration, resulting in a lower risk of systemic effects. Pimecrolimus has high anti-inflammatory activity in animal models of skin inflammation, including a model reflecting neurogenic inflammation, but a more favourable balance of anti-inflammatory vs. immunosuppressive activity than tacrolimus. Pimecrolimus does not affect sensitization in a murine model of allergic contact dermatitis and has a lower potency in various models of immunosuppression after systemic administration, compared to tacrolimus. In conclusion, the results of preclinical studies show that pimecrolimus has a selective pharmacological profile, suited for effective and safe treatment for inflammatory skin diseases.

Drug discovery and development for inflammatory diseases

Numerous recent investigations have pointed to a key role of the pro-inflammatory, pleotropic cytokines TNF-alpha and IL-1 in host defence and inflammatory disease processes. TNF and IL-1 overexpression has been found in disease target tissue and in the circulation of patients with acute and chronic inflammatory diseases, and it was suggested early on in this field of basic medical research that TNF-alpha and IL-1 were crucial in these diseases. Over the last 10 years, several approaches to inhibit TNF-alpha and, in one case, IL-1 activity, have been developed by the biotechnology and pharmaceutical industries. These include neutralising antibodies to TNF-alpha as well as soluble TNF-alpha receptors with characteristic properties designed to bind the 17 kDa soluble trimeric TNF-alpha and the 26 kDa membrane-bound form of TNF-alpha. Clinical trials have demonstrated significant effects with these agents and it is likely that blocking TNF-alpha will become an important standard therapeutic option for clinicians. The data available from these trials contribute to the further understanding of inflammation by demonstrating the major role of these cytokines. This research and clinical background have provided the basis for a variety of lectures on novel drug discovery targets, the current status of previously identified targets and technologies to develop new therapeutics in inflammation. At this meeting, emphasis was placed upon drug targets and their validation in animal models and early stage clinical trials.

Pimecrolimus inhibits the elicitation phase but does not suppress the sensitization phase in murine contact hypersensitivity, in contrast to tacrolimus and cyclosporine A

Pimecrolimus (SDZ ASM 981, Elidel) is a nonsteroid inflammatory cytokine inhibitor specifically developed for the treatment of inflammatory skin diseases. Its effect on the elicitation and sensitization phases of oxazolone-induced contact hypersensitivity was compared with tacrolimus and cyclosporine A (CyA) in BALB/c mice using the ear swelling assay. The compounds were administered orally. Elicitation was dose-dependently inhibited by all three compounds. The minimal effective doses were 30 mg per kg (pimecrolimus, tacrolimus) and 90 mg per kg (CyA), respectively. There was no impairment of sensitization by pimecrolimus up to the highest dose tested (120 mg per kg), in contrast to CyA (60% inhibition at 60 mg per kg) and tacrolimus (71% inhibition at 30 mg per kg). Weight and cellularity of the draining lymph nodes in mice treated with tacrolimus or CyA during sensitization were reduced. In addition, proliferation of T cells after secondary stimulation was inhibited in cell cultures from lymph nodes of mice treated with tacrolimus or CyA. Thus, in contrast to tacrolimus and CyA, pimecrolimus exerts a more selective immunomodulatory effect. It does not impair the primary immune response (sensitization phase) but effectively inhibits the secondary phase, the elicitation phase that is the clinical manifestation of contact hypersensitivity.

[Development and pre-clinical aspects of pimecrolimus]

Pimecrolimus (SDZ ASM 981), an ascomycin derivative, inhibits the phosphatase calcineurin and blocks the production of inflammatory cytokines in T cells. In contrast to corticosteroids, pimecrolimus has a cell selective mode of action, exerting e.g. no effect on dendritic cells, which have a central function in the skin-associated immune system. Pimecrolimus shows less permeation through skin than corticosteroids and tacrolimus which indicates a lower potential for systemic side effects after topical application. In animal models pimecrolimus has a marked dose-dependent anti-inflammatory activity. However, treatment with pimecrolimus does not induce skin atrophy in contrast to corticosteroids. In contrast to tacrolimus, pimecrolimus does not impair the primary immune reaction in the sensitization phase of allergic contact dermatitis and has generally less effect on systemic immune reactions. In summary, the pharmacological profile of pimecrolimus suggests high clinical efficacy together with excellent safety.

[New immunosuppressive agents for treating psoriasis]

Accumulative evidence suggests that psoriasis may be a genetically determined immunologenic inflammatory disorder based on an ongoing autoreactive Th-1 response. Various cytokines (e.g. IL-2, interferon-gamma etc.) are released and exert proliferative signals on to keratinocytes, which start proliferation that finally results in an incomplete differentiation. During this pathobiological process keratinocytes themselves express receptors that make them sensitive for growth inducing stimulation and also start the production of a set of cytokines that contribute to and maintain inflammation. Immunosuppressive agents, mostly by affecting T-cells may interfere with or even disrupt by rather unspecific mechanisms, this complex process of mutual stimulation of leucocytes and keratinocytes. In this manuscript we show mode of action, efficacy and side effects of Methotrexate, Ciclosporin A, Tacrolimus and Pimecrolimus, and discuss therapeutic options with mycophenolate mofetil and fumaric acid esters.