Atopic dermatitis-like symptoms in hypomagnesaemic hairless rats are prevented and inhibited by systemic or topical SDZ ASM 981

Improvement of Skin Symptoms and Mineral Imbalance by Drinking Deep Sea Water in Patients with Atopic Eczema/Dermatitis Syndrome (AEDS)

Deep sea water intake improves skin symptoms and mineral imbalance and decreases serum IgE levels mad IgEinducing cytokines, IL-4, IL-13 and IL-18 in patients with atopic eczema/dermatitis syndrome (AEDS), while distilled water intake fails to do so.

Transient receptor potential channels and itch: how deep should we scratch?

Over the past 30 years, transient receptor potential (TRP) channels have evolved from a somewhat obscure observation on how fruit flies detect light to become the center of drug discovery efforts, triggering a heated debate about their potential as targets for therapeutic applications in humans. In this review, we describe our current understanding of the diverse mechanism of action of TRP channels in the itch pathway from the skin to the brain with focus on the peripheral detection of stimuli that elicit the desire to scratch and spinal itch processing and sensitization. We predict that the compelling basic research findings on TRP channels and pruritus will be translated into the development of novel, clinically useful itch medications.

Thermally activated TRPV3 channels

TRPV3 is a temperature-sensitive transient receptor potential (TRP) ion channel. The TRPV3 protein functions as a Ca(2+)-permeable nonselective cation channel with six transmembrane domains forming a tetrameric complex. TRPV3 is known to be activated by warm temperatures, synthetic small-molecule chemicals, and natural compounds from plants. Its function is regulated by a variety of physiological factors including extracellular divalent cations and acidic pH, intracellular adenosine triphosphate, membrane voltage, and arachidonic acid. TRPV3 shows a broad expression pattern in both neuronal and non-neuronal tissues including epidermal keratinocytes, epithelial cells in the gut, endothelial cells in blood vessels, and neurons in dorsal root ganglia and CNS. TRPV3 null mice exhibit abnormal hair morphogenesis and compromised skin barrier function. Recent advances suggest that TRPV3 may play critical roles in inflammatory skin disorders, itch, and pain sensation. Thus, identification of selective TRPV3 activators and inhibitors could potentially lead to beneficial pharmacological interventions in several diseases. The intent of this review is to summarize our current knowledge of the tissue expression, structure, function, and mechanisms of activation of TRPV3.

Oral intake of beet extract provides protection against skin barrier impairment in hairless mice

The epidermis acts as a functional barrier against the external environment. Disturbances in the function of this barrier cause water loss and increase the chances of penetration by various irritable stimuli, leading to skin diseases such as dry skin, atopic dermatitis, and psoriasis. Ceramides are a critical natural element of the protective epidermal barrier. The aim of this study was to evaluate whether the oral intake of beet (Beta vulgaris) extract, a natural product rich in glucosylceramide (GlcCer), may prevent disturbance in skin barrier function. When HR-1 hairless mice were fed a special diet (HR-AD), transepidermal water loss (TEWL) from the dorsal skin increased, with a compensatory increase in water intake after 5 weeks. Mice fed with HR-AD had dry skin with erythema and showed increased scratching behaviour. Histological examinations revealed a remarkable increase in the thickness of the skin at 8 weeks. Supplemental addition of beet extract, which contained GlcCer at a final concentration of 0.1%, significantly prevented an increase TEWL, water intake, cumulative scratching time, and epidermal thickness at 8 weeks. These results indicate that oral intake of beet extract shows potential for preventing skin diseases associated with impaired skin barrier function.

Tonic inhibition of TRPV3 by Mg2+ in mouse epidermal keratinocytes

The transient receptor potential vanilloid 3 channel (TRPV3) is abundantly expressed in epidermal keratinocytes and plays important roles in sensory biology and skin health. Mg²⁺ deficiency causes skin disorders under certain pathological conditions such as type 2 diabetes mellitus. In this study, we investigated the effect of Mg²⁺ on TRPV3 in primary epidermal keratinocytes. Extracellular Mg²⁺ ([Mg²⁺]_o) inhibited TRPV3-mediated membrane current and calcium influx. TRPV3 activation induced a calcium signaling pathway culminating in activation of the cAMP response element binding (CREB). TRPV3 inhibition by [Mg²⁺]_o, the TRPV3 blocker ruthenium red or TRPV3 siRNA suppressed this response. In TRPV3-expressing Chinese hamster ovary (CHO) cells, both extracellular and intracellular Mg²⁺ inhibited TRPV3 single-channel conductance but not open probability. Neutralization of an aspartic acid residue (D641) in the extracellular pore loop or two acidic residues (E679, E682) in the inner pore region significantly attenuated the inhibitory effect of extracellular or intracellular Mg²⁺ on TRPV3-mediated signaling, respectively. Our findings suggest that epidermal TRPV3 is tonically inhibited by both extracellular and intracellular Mg²⁺, which act on both sides of the channel pore loop. Mg²⁺ deficiency may promote the function of TRPV3 and contribute to the pathogenesis of skin diseases.

Tacrolimus ointment in the management of atopic dermatitis

Atopic dermatitis (AD) is a chronic, relapsing, highly pruritic inflammatory skin disease. AD long-term treatment is usually required to control and prevent flares, and patients need a treatment that is safe and efficacious when applied continuously or intermittently over a prolonged period of time. The treatment options should be chosen according to age, clinical features and severity of the disease in every single patient. For the treatment of a chronic disease like AD, sustained tolerability and efficacy of the applied medications are essential. A topical immunomodulator, tacrolimus ointment, provides an alternative to topical corticosteroids without the associated adverse events. Tacrolimus is a macrolide lactone with unique immunomodulatory properties and strong anti-inflammatory activities and can be used without increasing the risk of infection or other non-application site adverse events, and without loss of effectiveness, in patients with AD.

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.

In vivo pharmacological disease models for psoriasis and atopic dermatitis in drug discovery

In order to perform relevant in vivo pharmacological investigations in drug discovery within dermatology it is fundamental to master or have access to relevant skin disease models that makes it possible to identify and validate targets and to screen and discover drugs in vivo. There is a strong need for highly predictive in vivo models in order to introduce the right drug candidates into the clinical phases of development. Recent advances in dermatological in vivo pharmacological disease models for psoriasis and atopic dermatitis are reviewed together with a discussion of the rationale for their application in drug discovery.

Magnesium and the inflammatory response: potential physiopathological implications

The purpose of this review is to summarize experimental findings showing that magnesium modulates cellular events involved in inflammation. Experimental magnesium deficiency in the rat induces after a few days a clinical inflammatory syndrome characterized by leukocyte and macrophage activation, release of inflammatory cytokines and acute phase proteins, excessive production of free radicals. Increase in extracellular magnesium concentration, decreases inflammatory response while reduction in the extracellular magnesium results in cell activation. Because magnesium acts as a natural calcium antagonist, the molecular basis for inflammatory response is probably the result of modulation of intracellular calcium concentration. The priming of phagocytic cells, the opening calcium channel and activation of N-methyl-d-aspartate (NMDA) receptors, the activation of nuclear factor-kappa B (NFkappaB) have been considered as potential mechanisms. Moreover, magnesium deficiency induces a systemic stress response by activation of neuro endocrinological pathways. As nervous and immune systems interact bidirectionally, the roles of neuromediators have also been considered. Magnesium deficiency contributes to an exaggerated response to immune stress and oxidative stress is the consequence of the inflammatory response. Inflammation contributes to the pro-atherogenic changes in lipoprotein metabolism, endothelial dysfunction, thrombosis, hypertension and explains the aggravating effect of magnesium deficiency on the development of metabolic syndrome. Further studies are still needed to assess more accurately the role of magnesium in immune response in humans, but these experimental findings in animal models suggest that inflammation is the missing link to explain the role of magnesium in many pathological conditions.

Drinking deep-sea water restores mineral imbalance in atopic eczema/dermatitis syndrome

OBJECTIVE

The effect of drinking deep-sea water on hair minerals was studied in patients with atopic eczema/dermatitis syndrome (AEDS). Study of hair minerals revealed an imbalance of essential minerals and an increase in toxic minerals in AEDS patients.

DESIGN

After drinking deep-sea water (Amami no Mizu) for 6 months in AEDS patients, hair minerals (essential minerals and toxic minerals), clinical evaluation of the skin symptoms were compared before drinking with after drinking.

SUBJECTS

After obtaining informed consent, 33 patients (mean age 26 y, range 1-50 y, 13 male and 20 female subjects) with mild to moderate AEDS were enrolled.

RESULTS

After drinking deep-sea water, the levels of the essential mineral, potassium (K), were significantly decreased, while the levels of selenium (Se) increased. On the other hand, drinking deep-sea water significantly decreased the levels of the toxic minerals, mercury and lead. Moreover, after drinking deep-sea water, the skin symptoms were improved in 27 out of 33 patients.

CONCLUSION

These results indicate that the mineral abnormalities/imbalance may be involved in the pathogenesis of AEDS, and that drinking deep-sea water may be useful in the treatment of AEDS.

Experimental approaches to lymphocyte migration in dermatology in vitro and in vivo

Lymphocyte trafficking through the dermal compartment is part of the physiological surveillance process of the adaptive immune system. On the other hand, persistent or recurrent lymphocyte infiltrates are hallmarks of both types of chronic inflammatory skin diseases, Th1-type such as psoriasis or Th2/allergic-type like atopic dermatitis. A better understanding of the mechanisms underlying lymphocyte movements is one of the key prerequisites for developing more effective therapies. In this review, we introduce a range of simple-to-sophisticated experimental in vitro and in vivo approaches to analyze lymphocyte migration. These methods start from static in vitro adhesion and chemotaxis assays, include dynamic endothelial flow chamber, intravital dual photon, and transcutaneous live-video microscopy, and finally encompass specific genetically deficient or engineered animal models. Discussing pros and cons of these assay systems hopefully generates both state-of-the-art knowledge about the factors involved in most common chronic skin diseases as well as an improved understanding of the limitations and chances of new biologic pharmaceuticals that are currently introduced into clinical practice.

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 hypomagnesic rat model: dermatitis-prone hairless rats with mild magnesium depletion fed a diet low in lipids did not develop pruritic dermatitis

BACKGROUND/PURPOSE

In the hypomagnesic dermatosis of rats, low-dietary magnesium leads to lowered serum Mg2+, universal dermatitis and scratching. The model is postulated to work better if the diet also has a low content of lipids. Pruritus is seen in patients suffering from anorexia nervosa and resolves on weight restoration. Lipid depletion of the diet and/or lowered body weight may therefore be important in developing pruritus. The purpose of the present study was to investigate whether a diet low in lipids can induce pruritus in dermatitis prone rats because of mild magnesium depletion thereby focusing on the role of lipids in the hypomagnesic dermatosis rat model.

METHODS

Fourteen male hairless rats, 3 weeks of age, were fed a diet deficient in lipids and with a lower content of magnesium for a 4-week period and compared with 11 controls fed a normal diet. The skin was inspected daily and transepidermal water loss (TEWL), serum Mg2+ and scratching activity were measured. At the end, skin biopsies were taken from the flank and ears.

RESULTS

Serum Mg2+ was significantly lowered in the diet group (P<0.001) but the rats developed no dermatitis or increased TEWL compared with 11 rats in a control group. Biopsies were normal with no sign of inflammation. Rats in the diet group had inferior weight gain, were less active and spent more time asleep than control rats (P<0.01). Furthermore, scratching activity monitored in the last week of the study as the number of scratch-sequences per awake minute was reduced in the diet group (P<0.001).

CONCLUSION

The lipid-deficient diet was not able to induce pruritic dermatitis despite the fact that the rats were dermatitis prone because of mild magnesium depletion. It is not confirmed that dietary lipid depletion plays any significant role in the hypomagnesic dermatitis rat model. The dermatitis and the model appear to be strictly dependent on efficient magnesium depletion manufactured with very low magnesium levels.

Sargassum hemiphyllum inhibits atopic allergic reaction via the regulation of inflammatory mediators

Sargassum hemiphyllum (SH) has long been used in Korean folk medicine for the therapeutic treatment of various allergic diseases. The effects of SH in previous experimental models, however, have been inconclusive. We studied the effects of methanol extract of SH on mast cells. Our experiments showed that SH significantly inhibited compound 48/80-induced histamine and beta-hexosaminidase release from rat peritoneal mast cells. SH inhibited interleukin (IL)-8 and tumor necrosis factor (TNF)-alpha release induced by phorbol 12-myristate 13-acetate and A23187 from HMC-1, and it also showed an inhibitory effect on the anti-dinitrophenyl IgE antibody-induced passive cutaneous anaphylaxis reaction. In addition, SH inhibited the increase of TNF-alpha-induced NF-kappaB protein levels, transcription factor of TNF-alpha from 293T cells. A period of 48 h exposure to SH had little effect on HMC-1 cell viability. Our results suggest that SH has an inhibitory effect on the atopic allergic reaction and thus this may be useful in the treatment of allergic inflammatory diseases, such as atopic dermatitis.

Atopic dermatitis-like symptoms in HR-1 hairless mice fed a diet low in magnesium and zinc

We aimed to develop an animal model for atopic dermatitis. HR-1 hairless mice fed a diet with reduced magnesium and zinc levels were compared with mice fed a standard diet. Skin dryness and wrinkle-like changes, scratching behaviour, decreased skin water content, increased transepidermal water loss and raised blood immunoglobulin E levels were seen in the group receiving the reduced magnesium and zinc diet compared with control mice. There were no significant differences in body weight or the weight of the major organs between the two groups. Haematological examination in both groups was normal apart from increased immunoglobulin E levels in mice fed a reduced magnesium and zinc diet. These mice may be useful models of atopic dermatitis; preparation of the animals is not particularly time consuming, the reproducibility is 100%, and atopic dermatitis symptoms occur even in a specific pathogen-free environment.

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.

Current concepts and review of pimecrolimus in the treatment of psoriasis

The ascomycine macrolactam derivative pimecrolimus has a gene profile of broad anti-inflammatory activity without evidence of toxicity. It exhibits excellent clinical tolerability after 4 weeks and 12 weeks, respectively, of oral treatment, and it is highly effective in a concentration-dependent manner in patients with moderate to severe plaque psoriasis. Although not yet approved, oral pimecrolimus promises to be a novel, highly effective, and well-tolerated drug in the systemic treatment of psoriasis and other T-cell-mediated skin diseases.

Pimecrolimus: a review of its use in atopic dermatitis

Pimecrolimus (Elidel) is a topically active, nonsteroid, calcineurin inhibitor that has shown efficacy in controlling symptoms of atopic dermatitis in adult and pediatric patients. Topical pimecrolimus 1% cream is approved in the US for the short-term and intermittent long-term treatment of mild-to-moderate atopic dermatitis in non-immunocompromised patients aged >/=2 years who do not respond well to, or may have adverse effects with, conventional treatments. Pimecrolimus 1% cream is an effective and well tolerated treatment for atopic dermatitis in infants, children, adolescents, and adults. Pimecrolimus is effective at reducing the incidence of disease flares and, thus, the need for rescue treatment with topical corticosteroids. The drug also improves the health-related quality of life (HR-QOL) of children and adolescents, and improves the QOL of parents of children with atopic dermatitis. Furthermore, pimecrolimus does not cause skin atrophy, a problem commonly associated with topical corticosteroids, and is not associated with clinically relevant systemic adverse events. Thus, topical pimecrolimus 1% cream is an effective treatment option for the management of mild-to-moderate atopic dermatitis.

Pimecrolimus: a review

Pimecrolimus (SDZ ASM 981), an ascomycin derivative, is one of the new classes of immunomodulating macrolactams and was specifically developed for the treatment of inflammatory skin diseases. The interest in pimecrolimus has been substantial because of its significant anti-inflammatory activity and immunomodulatory capabilities and its low systemic immunosuppressive potential. The mechanism of action of pimecrolimus is the blockage of T cell activation. Pimecrolimus (like all ascomycins) is an immunophilin ligand, which binds specifically to the cytosolic receptor, immunophilin macrophilin-12. This pimecrolimus-macrophilin complex effectively inhibits the protein phosphatase calcineurin, by preventing calcineurin from dephosphorylating the nuclear factor of activated T cells (NF-AT), a transcription factor. This results in the blockage of signal transduction pathways in T cells and the inhibition of the synthesis of inflammatory cytokines, specifically Th1- and Th2-type cytokines. Pimecrolimus has also been shown to prevent the release of cytokines and pro-inflammatory mediators from mast cells. Several studies have evaluated the effectiveness of pimecrolimus as a treatment for skin diseases. In animal models of allergic contact dermatitis, topical pimecrolimus was found to be effective. In human studies of allergic contact dermatitis pimecrolimus demonstrated significantly more efficacy than the control treatment. As well, the effectiveness of pimecrolimus 0.6% cream was comparable to 0.1% betamethasone-17-valerate; however, pimecrolimus was not associated with any of the side effects characteristic of a topical steroid. Topical application of pimecrolimus is not associated with skin atrophy. Pimecrolimus is effective and safe in both children and adults with atopic dermatitis. When pimecrolimus 1% cream has been applied to adult atopics, improvement has been observed as early as the first week, with a 72% reduction in severity after 3 weeks. Pharmacokinetic studies have shown very low blood levels of pimecrolimus following topical application, with no accumulation after repeated applications. Following application of pimecrolimus cream occasional transient irritation may be experienced at the application site. Similar results have also been found in children aged 3 months and older following application of pimecrolimus 1% cream. Topical pimecrolimus in psoriasis appears to exhibit a dose-dependent therapeutic effect under semi-occlusive conditions. Pimecrolimus has an enormous potential as a new treatment of inflammatory skin diseases. It has been shown to be effective in atopic and allergic contact dermatitis, with a favorable adverse-effects profile, which includes little effect on the systemic immune response.

[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.

[Antipruritic effects of pimecrolimus and tacrolimus]

The development of topical calcineurin inhibitors resulted in a significant improvement in the treatment of inflammatory skin diseases such as atopic dermatitis. In addition, an excellent amelioration of pruritus could be observed. Other itchy dermatoses such as chronic irritative hand dermatitis, rosacea, graft-versus-host-disease, renal pruritus, lichen sclerosus, prurigo simplex, prurigo nodularis, scrotal eczema, and inverse psoriasis also have been treated successfully with pimecrolimus and tacrolimus. The antipruritic effect currently is believed to be related to the inhibition of inflammatory cytokines. Furthermore, recent investigations indicate a release of neuropeptides from sensory nerve fibers and degranulation of mast cells mediated by pimecrolimus and tacrolimus. Similar effects have been observed during capsaicin treatment. These findings may provide a possible explanation for initially observed calcineurin inhibitors related side-effects such as burning and pruritus. Moreover, the antipruritic potency may be related to a direct effect on nerve fibers leading to suppression of itch mediated by unknown mechanisms.

Pimecrolimus identifies a common genomic anti-inflammatory profile, is clinically highly effective in psoriasis and is well tolerated

The ascomycin macrolactam pimecrolimus is a novel inflammatory cytokine release inhibitor that so far has not been administered systemically to humans. In this phase I/II randomized double-blind, placebo-controlled, multiple rising dose proof of concept study psoriasis patients were treated with oral pimecrolimus or placebo. Gene profiling identified a common genomic profile with a downregulation of genes associated with inflammation but no changes in gene expression linked to drug-related side-effects. A steady state of pimecrolimus was reached after 5-10 d, Cmax, and area under the curve (0-24) was 54.5 ng per ml and 589.9 ng h per ml, respectively, at steady state at the highest dose. There was clear clinical efficacy in patients receiving 20 mg pimecrolimus twice daily and 30 mg twice daily with a reduction of Psoriasis Area and Severity Index by 60% and 75%, respectively. Histopatho logically and immunopathologically there was a reversion of the psoriatic phenotype towards normal. There were no notable clinical, laboratory, kidney function, or immunologic side-effects. We conclude that pimecrolimus taken orally is highly effective in a concentration-dependent manner in patients with psoriasis and on a short-term basis it is well tolerated and this is confirmed by its pharmacogenomic profile. The latter also indicates that pimecrolimus should be equally effective in other inflammatory skin diseases.

Topical pimecrolimus: a review of its clinical potential in the management of atopic dermatitis

Pimecrolimus (SDZ ASM 981), an ascomycin derivative, is a nonsteroid, has anti-inflammatory activity, and has demonstrated efficacy in reducing symptoms of atopic dermatitis in adult and paediatric patients when applied topically. Compared with vehicle, topical pimecrolimus 1.0% cream was significantly more effective at reducing symptoms of atopic dermatitis, as measured by the Eczema Area and Severity Index (EASI), in infants aged 3 to 23 months, children aged 2 to 17 years and adults. The median reductions from baseline in the total EASI score in adults after treatment with pimecrolimus 1.0% or corresponding vehicle twice daily for 3 weeks were 47 and 0%, respectively. In infants and children, treatment with pimecrolimus 1.0% twice daily for 6 weeks resulted in significant decreases in mean EASI scores compared with vehicle. The severity of pruritus was significantly reduced in patients of all age groups after topical treatment with pimecrolimus 1.0% cream. Compared with vehicle, the incidence of eczematous flares was also reduced by intermittent long-term use of topical pimecrolimus 1.0% in adults, children and infants. Sixty percent of children treated with pimecrolimus for 1 year completed the first 6 months of treatment without experiencing a flare, compared with 35% of patients who received vehicle. Furthermore, the use of topical corticosteroids for the treatment of uncontrolled flares in adults, children and infants was lower in the pimecrolimus groups than in the vehicle groups. Topical pimecrolimus 1.0% cream is well tolerated in atopic dermatitis patients of all age groups. There were no clinically relevant systemic adverse events reported from any of the studies in patients with atopic dermatitis. The most frequently reported adverse events pertained to application site reactions, such as burning and a feeling of warmth. In conclusion, topical pimecrolimus 1.0% cream has shown efficacy in the treatment of mild to moderate atopic dermatitis in infants, children and adults. Although tolerability data concerning infants and children have not yet been published in full, the drug appears to be well tolerated in all age groups, and there have been no reports of clinically relevant systemic adverse events. Furthermore, pimecrolimus 1.0% cream has shown no potential for skin atrophy, a problem commonly associated with treatment with topical corticosteroids. Pimecrolimus 1.0% cream provides a promising and well tolerated treatment option in the management of infants, children and adults with mild to moderate atopic dermatitis.

Safety and efficacy of pimecrolimus (ASM 981) cream 1% in the treatment of mild and moderate atopic dermatitis in children and adolescents

BACKGROUND

The ascomycin derivative pimecrolimus (ASM 981) is a cell-selective cytokine inhibitor, specifically developed for the treatment of inflammatory skin diseases.

OBJECTIVE

When applied topically, pimecrolimus cream 1% has shown promise as a treatment for inflammatory skin conditions, including atopic dermatitis (AD) in children and adults, allergic contact dermatitis, and chronic contact irritant hand dermatitis in adults.

METHODS

In two independent 6-week, randomized, multicenter studies of identical design, the efficacy and safety of pimecrolimus cream 1% in children with predominantly moderate AD were compared with vehicle. Pooled data from a total of 403 patients were used in the analysis. The primary efficacy parameter was the Investigator's Global Assessment (IGA) score. Secondary parameters included Eczema Area and Severity Index (EASI) and severity of pruritus scores. Subjects were also asked to assess their disease control as uncontrolled, limited, good, or complete.

RESULTS

Significant therapeutic benefits relative to vehicle were observed in the pimecrolimus-treated group at the first efficacy assessment, 8 days after initial application of the study medication (eg, relief of pruritus). At each subsequent postbaseline visit, pimecrolimus-treated patients showed significant improvement relative to controls in all efficacy measures. The medication was well tolerated.

CONCLUSION

Pimecrolimus cream 1% appears to be a safe and effective alternative to currently used therapies for AD.

New and established topical corticosteroids in dermatology: clinical pharmacology and therapeutic use

Currently, topical glucocorticosteroids are the most frequently used drugs in dermatologic practice. Over the years, research has focused on strategies to optimize potency and, in particular, the anti-inflammatory and immunosuppressive capacity of these drugs, while minimizing adverse effects. However, 'ideal' topical corticosteroids have not yet been synthesized. They should be able to permeate the stratum corneum and reach adequate concentrations in the skin without reaching high serum concentrations. Such characteristics can be obtained by increasing the natural lipophilicity of corticosteroids, e.g. by esterification. In the past, many structural modifications have been made to improve the efficacy of topical corticosteroids to produce drugs with greater potency, although this has often been associated with a higher likelihood of adverse effects. Betamethasone dipropionate and clobetasol propionate, known as fifth-generation corticosteroids, are a typical example of potent molecules that can control specific dermatoses very rapidly, but which are associated with a high risk of topical and systemic adverse effects. Recently, steroid components have been synthesized that aim to have adequate anti-inflammatory effects and minimal adverse effects. The newest topical corticosteroids used for the treatment of different dermatoses and allergic reactions of the respiratory tract (in particular asthma) are budesonide, mometasone furoate, prednicarbate, the di-esters 17,21-hydrocortisone aceponate and hydrocortisone-17-butyrate-21-propionate, methylprednisolone aceponate, alclometasone dipropionate, and carbothioates such as fluticasone propionate. These new topical corticosteroids are evaluated in the current review, which compares the risk/benefit ratio of each molecule with established agents. The new molecules, compared with the well known and established corticosteroids, generally have a higher anti-inflammatory effect, good compliance among patients (only a once-daily application is needed), rarely induce cross-sensitivity reactions and have weak atrophogenicity.

Pimecrolimus (Elidel, SDZ ASM 981)--preclinical pharmacologic profile and skin selectivity

The ascomycin macrolactam derivative pimecrolimus (Elidel, SDZ ASM 981; Novartis Pharma AG, Basel Switzerland) is a cell-selective inhibitor of inflammatory cytokines specifically developed for the treatment of inflammatory skin diseases, such as atopic dermatitis, allergic contact dermatitis, irritant contact dermatitis, and plaque-type psoriasis. It inhibits the production of inflammatory cytokines in T cells and mast cells and prevents the release of preformed inflammatory mediators from mast cells. Topically administered pimecrolimus is as effective as the high-potency corticosteroid clobetasol-17-propionate in a pig model of allergic contact dermatitis (ACD). Unlike clobetasol, however, it does not cause skin atrophy. Given orally, pimecrolimus is as potent or superior to tacrolimus (FK 506) in treating ACD in mice and rats. Pimecrolimus also effectively reduces skin inflammation and pruritus in hypomagnesemic hairless rats, a model that mimics acute signs of atopic dermatitis. Pimecrolimus shows only a low potential to impair systemic immune responses when compared with tacrolimus as shown in rats in (1) the localized graft-versus-host reaction, (2) the antibody formation to sheep red blood cells, and (3) kidney transplantation. Pimecrolimus permeates through pig skin in vitro at a 10-times lower rate than tacrolimus, indicating a lower potential for percutaneous absorption in vivo. The data suggest that pimecrolimus combines high anti-inflammatory activity in the skin with a low potential to impair systemic immune reactions.

The role of NO in contact hypersensitivity

Contact dermatitis or contact hypersensitivity (CHS) is a common T lymphocyte-mediated allergic disease characterized by local inflammatory skin reactions following contact with small reactive compounds called haptens. In common with other allergic processes, the development of contact dermatitis proceeds in two phases: a sensitization phase which occurs on first exposure to allergen, and an elicitation phase which occurs on subsequent exposure when the clinical manifestations of the disease are observed. This process is hapten-specific. While the pathophysiology of the sensitization phase is well characterized, our understanding of the elicitation phase is still incomplete, including the relative contribution of the different effector cells and mediators involved. Here we summarize current knowledge of the contribution of nitric oxide (NO) to skin inflammation with special focus on CHS. A number of inflammatory stimuli trigger expression of NO in human and animal skin, and topical application of an NO-releasing cream results in inflammation. Moreover, expression of the inducible isoform of nitric oxide synthase (iNOS) is induced in CHS and iNOS inhibitors injected intradermally suppress CHS responses. However, iNOS-deficient mice develop an aggravated CHS response late in the elicitation phase, suggesting that NO is involved in downregulation of CHS. Based on these data, we propose a comprehensive model of the role of NO in CHS.

The ascomycin macrolactam pimecrolimus (Elidel, SDZ ASM 981) is a potent inhibitor of mediator release from human dermal mast cells and peripheral blood basophils

BACKGROUND

The ascomycin macrolactam pimecrolimus (Elidel, SDZ ASM 981) has recently been developed as a novel and cell-selective inhibitor of inflammatory cytokine secretion; it has fewer adverse effects than currently available drugs.

OBJECTIVE

In this study, we investigated the capacity of pimecrolimus to directly inhibit in vitro mediator release from human skin mast cells and basophils.

METHODS

Purified cutaneous mast cells or basophil-containing peripheral blood leukocytes were obtained from healthy human donors and preincubated with pimecrolimus (0.1 nmol/L to 1 micromol/L) in the absence or presence of its specific antagonist (rapamycin), cyclosporin A (100 nmol/L to 1 micromol/L), or dexamethasone (1 micromol/L) and then stimulated with anti-IgE or with calcium ionophore A23187 plus phorbol myristate acetate. Cell supernatants were kept for analysis of histamine, tryptase, LTC4, and TNF-alpha.

RESULTS

Pimecrolimus caused a strong and dose-dependent inhibition of anti-IgE--induced release of histamine from mast cells and basophils (maximally 73% and 82%, respectively, at 500 nmol/L pimecrolimus) and of mast cell tryptase (maximally 75%) and a less pronounced inhibition of LTC4 (maximally 32%) and of calcium ionophore plus phorbol myristate acetate--induced mast cell TNF-alpha release (90% maximum at 100 nmol/L pimecrolimus). In contrast, inhibition achieved during mast cell histamine release was maximally 60% with cyclosporin A and only 28% with dexamethasone.

CONCLUSION

These data demonstrate a marked inhibitory capacity of pimecrolimus on mediator release from human mast cells and basophils with a potency exceeding that of cyclosporin A and dexamethasone. Pimecrolimus might thus be expected to be effective in the treatment of mast cell-- and basophil-dependent diseases.