Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.3.16 (calcineurin)
 17,112 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tacrolimus ointment, formulated for the treatment of atopic dermatitis, is the first in a class of topical immunomodulators. Its mechanism of action is based on calcineurin inhibition, which results in suppression of antigen-specific T-cell activation and inhibition of inflammatory cytokine release. Animal and human studies have shown that topically applied tacrolimus is minimally absorbed into the systemic circulation, the fraction that is absorbed is extensively distributed, and tacrolimus does not accumulate in tissues following repeated topical application. In addition, tacrolimus ointment is not inherently irritating, sensitizing, phototoxic, or photoallergenic when applied to intact skin. Unlike some topical corticosteroids, tacrolimus ointment does not cause a decrease in collagen synthesis or skin thickness, nor does it produce skin abnormalities or depigmentation. In animal studies, repeated daily application of tacrolimus ointment up to 1 year is associated with dermal findings similar to those following vehicle application (mild to moderate dermal irritation and microscopic findings of acanthosis, hyperkeratosis, and superficial inflammation). In a 52-week study with Yucatan micropigs, no noteworthy macroscopic or microscopic changes (either dermal or systemic) related to the application of tacrolimus ointment (0.03% to 0.3% concentrations) were observed. Tacrolimus ointment was shown to be safe and effective in phase 2 and early phase 3 studies. Significant improvements in atopic dermatitis were observed in the majority of patients treated with tacrolimus ointment. The most common adverse events associated with its use were a transient burning sensation and pruritus at the site of application. Blood tacrolimus concentrations were below the limit of quantitation in most patients.
J Am Acad Dermatol 2001 Jan
PMID:Nonclinical and early clinical development of tacrolimus ointment for the treatment of atopic dermatitis. 1114 92

The immunomodulatory macrolactams provide an alternative to glucocorticosteroids for the topical treatment of atopic dermatitis and other inflammatory dermatoses. Tacrolimus (FK506), as well as the newer ascomycin derivative ASM 981 (pimecrolimus), penetrate the inflamed epidermis and are suitable for topical therapy. Both substances inhibit the transcription of proinflammatory cytokine genes such as interleukin 2, which are dependent on the nuclear factor NF-AT. They block the catalytic function of calcineurin, which leads to the inhibition of the transport of the cytoplasmic component of NF-AT to the cell nucleus. Multicenter, randomized, double-blind clinical trials with topical formulations have shown the efficacy of both substances in moderate to severe atopic dermatitis. A review is presented of the biochemical and cell biologic properties, mode of action, pharmacokinetic data, side effects, results of the clinical trials, and further indications for tacrolimus and ASM 981, along with an overview of the related substances cyclosporine and sirolimus (rapamycin).
J Am Acad Dermatol 2001 Nov
PMID:Macrolactam immunomodulators for topical treatment of inflammatory skin diseases. 1160 25

Tacrolimus ointment, a topical inhibitor of the phosphatase calcineurin, has recently been approved in the United States for use in the treatment of atopic dermatitis. It is the first topical immune suppressant that is not one of the hydrocortisone derivatives, important allies in dermatology for nearly 50 years. Although tacrolimus is less able to penetrate thick skin than glucocorticoids, it does not cause dermal atrophy, an important advantage over the hydrocortisone class. Pimecrolimus (ASM 981), a newer calcineurin inhibitor closely related to tacrolimus, is also being developed for atopic dermatitis therapy. Pimecrolimus has an altered skin penetration profile but the same mechanism of action as tacrolimus. In this review we chronicle the discovery of the calcineurin inhibitors, their presumed evolutionary role as a bacterial "smart bomb" against fungi, molecular and cellular mechanisms of action in the immune system, systemic and topical side effects, efficacy in atopic dermatitis, and future applications within the specialty of dermatology. Particular attention is given to the issues of systemic absorption of tacrolimus, the conditions in which absorption can become a concern, efficacy relative to glucocorticoids, and the choice of 0.03% or 0.1% tacrolimus ointment for use in adults and children.
J Am Acad Dermatol 2002 Feb
PMID:Tacrolimus and pimecrolimus: from clever prokaryotes to inhibiting calcineurin and treating atopic dermatitis. 1180 35

Systemic cyclosporin A and tacrolimus are effective treatments for psoriasis. Cyclosporin A and tacrolimus block T cell activation by inhibiting the phosphatase calcineurin and preventing translocation from the cytoplasm to the nucleus of the transcription factor nuclear factor of activated T cells (NFAT). Inhibition of T cell activation is thought to account for their therapeutic action in psoriasis. We investigated whether nonimmune cells in human skin express calcineurin and NFAT1 and whether cyclosporin A and tacrolimus block activation of calcineurin/NFAT in epidermal keratinocytes. The expression patterns of the principal components of calcineurin/NFAT signaling pathway in normal human skin and psoriasis were determined by immunohistochemistry. We assessed calcineurin/NFAT activation in cultured keratinocytes by measuring the degree of nuclear localization of calcineurin and NFAT1 using immunofluorescence/confocal microscopy and assessed if cyclosporin A and tacrolimus blocked nuclear translocation of these proteins. A variety of cell types in normal and psoriatic skin expressed calcineurin and NFAT1, but expression was particularly prominent in keratinocytes. The principal cyclosporin A and tacrolimus binding proteins cyclophilin A and FKBP12 were also expressed by keratinocytes and nonimmune cells in skin. NFAT1 was predominantly nuclear in normal basal epidermal keratinocytes. Increased nuclear localization of NFAT1 was observed in suprabasal keratinocytes within lesional and to a lesser extent nonlesional psoriatic epidermis compared to normal skin (p = 0.001 and p = 0.03, respectively), suggesting increased activation of calcineurin in psoriatic epidermal keratinocytes. Agonists that induce keratinocyte differentiation, specifically 12-0-tetradecanoyl-phorbol-13-acetate (TPA) plus ionomycin, TPA, and raised extracellular calcium, induced nuclear translocation of NFAT1 and calcineurin in keratinocytes that was inhibited by pretreatment with cyclosporin A or tacrolimus. In contrast in human dermal fibroblasts, TPA plus ionomycin or TPA did not significantly alter the proportion of nuclear-associated NFAT1. These data provide the first evidence that calcineurin is functionally active in human keratinocytes inducing nuclear translocation of NFAT1 and also indicate that regulation of NFAT1 nuclear translocation in skin is cell type specific. Inhibition of this pathway in epidermal keratinocytes may account, in part, for the therapeutic effect of cyclosporin A and tacrolimus in skin diseases such as psoriasis.
J Invest Dermatol 2002 May
PMID:Localization of calcineurin/NFAT in human skin and psoriasis and inhibition of calcineurin/NFAT activation in human keratinocytes by cyclosporin A. 1198 54

At present, the first-line drugs for treating atopic dermatitis are topical corticosteroids. They are effective when used short-term; however, long-term use of the corticosteroids is associated with suppressive effects on the connective tissue, seen as skin atrophy or resistance to therapy. Currently, two topical noncorticosteroid immunomodulators tacrolimus (FK506) and pimecrolimus (SDZ ASM 981) are under development, or already on the market in some countries for atopic dermatitis. These two compounds show structural similarity. In T lymphocytes they bind to the same cellular receptor, the FK-binding protein (FKBP) or macrophilin-12. Tacrolimus shows a 3-fold greater affinity to FKBP compared with pimecrolimus. The tacrolimus/ pimecrolimus-FKBP complex further binds to calcineurin, an enzyme vital for the early activation of T cells. The consequence of calcineurin binding is a lack of activation of both T helper cell types 1 and 2. Further effects of these compounds have been suggested on other inflammatory cells, such as Langerhans cells and mast cells/basophils. In contrast to corticosteroids, no suppressive effects on connective tissue cells have been observed. Taken together, treatment of inflammation results in healing of the barrier function of the skin. This again results in reduced bioavailability of the drug, as compared with systemic use. Placebo-controlled studies have shown the efficacy of both tacrolimus (at 0.03 and 0.1%) and pimecrolimus (at 0.6 and 1%). The main adverse event in these studies has been a burning sensation and increased pruritus at the site of application. Typically, these adverse events are observed only during the first days of treatment. Long-term safety studies, of up to one year, have not revealed any new adverse events. So far, long-term use of topical noncorticosteroid compounds has not been associated with signs of immune deficiency. Although there is currently no evidence for clinically relevant, prolonged adverse effects, some of these, such as an increased risk of photocarcinogenesis, need to be monitored. There is evidence from tacrolimus studies that monotherapy results in better long-term results when compared with combination therapy with corticosteroids. Tacrolimus and pimecrolimus could replace topical corticosteroids as the first-line treatment of atopic dermatitis.
Am J Clin Dermatol 2002
PMID:Topical noncorticosteroid immunomodulation in the treatment of atopic dermatitis. 1211 47

Macrolides are xenobiotics, produced by soil fungi, which have immunosuppressant properties. They will probably revolutionise the treatment of inflammatory dermatoses. This article outlines the context and putative mechanisms of action of this novel class of drugs. Cyclosporin, and the structurally distinct macrolides tacrolimus and pimecrolimus (an ascomycin derivative), modulate immune-cell function by inhibiting calcineurin-dependent dephosphorylation-activation of specific nuclear factors, thus preventing transcription of pro-inflammatory cytokines. The macrolide rapamycin (sirolimus) acts by abrogating Target of Rapamycin, a key signalling protein that controls activation of a number of proteins which direct progression of the cell cycle in response to pro-inflammatory cytokines. Tacrolimus and pimecrolimus are small enough molecules to penetrate skin and are available in topical formulations. "Skin-specific" pimecrolimus seems not to cause systemic immunosuppression when given orally. Neither topical tacrolimus nor pimecrolimus are capable of producing skin atrophy. Sirolimus has anti-angiogenic properties that may be beneficial to the treatment of psoriasis and perhaps skin cancer.
Eur J Dermatol
PMID:The macrolide immunosuppressants in dermatology: mechanisms of action. 1245 45

Controlled trials and clinical experience indicate that systemic cyclosporin A and tacrolimus are effective treatments for psoriasis, and that cyclosporin A also improves atopic eczema. A variety of other inflammatory and non-inflammatory skin diseases are probably also responsive to these drugs. However, the widespread and longer-term use of cyclosporin A and tacrolimus are limited by side effects. The molecular mechanisms of action of cyclosporin A, tacrolimus and a related drug, sirolimus, have been well defined in T cells and involve inhibition of critical signalling pathways that regulate T cell activation. For example cyclosporin and tacrolimus inhibit calcineurin phosphatase activity and thereby inhibit activation of the transcription factor NFAT. The therapeutic efficacy of topical calcineurin inhibitors in atopic eczema have restimulated interest in the mechanism of action of these drugs in skin disease. Recently the expression pattern of calcineurin and NFAT has been defined in non-immune tissues including the akin. The relevance of this to the mechanism of action of systemic and topical calcineurin inhibitors and sirolimus in skin disorders is discussed.
Clin Exp Dermatol 2002 Oct
PMID:Calcineurin inhibitors and sirolimus: mechanisms of action and applications in dermatology. 1246 50

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.
J Eur Acad Dermatol Venereol 2003 Sep
PMID:Pimecrolimus: a review. 1294 Oct 81

Many patients with atopic dermatitis feel that their treatment is ineffective and 25% may be noncompliant with treatments involving corticosteroids. Developing safe and effective pharmacologic alternatives to steroids has presented a challenge to physicians and drug researchers. A new class of nonsteroid immunomodulators, topical calcineurin inhibitors, overcome some of the difficulties and concerns associated with steroid use. The introduction of new drug therapies reinforces the importance of dermatology nursing in managing atopic dermatitis.
Dermatol Nurs 2003 Aug
PMID:Treatment options and new therapeutic approaches in atopic dermatitis. 1452 Aug 93

Tacrolimus ointment and pimecrolimus cream are approved in the United States for treatment of atopic dermatitis. Tacrolimus and pimecrolimus are both calcineurin inhibitors and function as immunosuppressants. Their mechanisms have been discussed elsewhere. This article will discuss their utility in treating psoriasis.
Dermatol Online J 2004 Jul 15
PMID:The use of topical tacrolimus and pimecrolimus to treat psoriasis: a review. 1534 85


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>