Rationale for use and clinical responsiveness of hexafluoro-1,25-dihydroxyvitamin D3 for the treatment of plaque psoriasis: a pilot study

Challenge and perspective: the relevance of ultraviolet (UV) radiation and the vitamin D endocrine system (VDES) for psoriasis and other inflammatory skin diseases

During evolution, the ability of many organisms to synthesize vitamin D photochemically represented, and still represents, a major driving factor for the development of life on earth. In humans because not more than 10-20% of the requirement of vitamin D can be satisfied by the diet (under most living conditions in the US and Europe), the remaining 80-90% need to be photochemically synthesized in the skin through the action of solar or artificial ultraviolet-B (UV-B) radiation. The skin is a key organ of the human body's vitamin D endocrine system (VDES), representing both the site of vitamin D synthesis and a target tissue for biologically active vitamin D metabolites. Human keratinocytes contain the enzymatic machinery (CYP27B1) for the synthesis of the biologically most active natural vitamin D metabolite 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃), representing an autonomous vitamin D₃ pathway. Cutaneous production of 1,25(OH)₂D₃ may mediate intracrine, autocrine and paracrine effects on keratinocytes and on neighboring cells. Many skin cells (including keratinocytes, sebocytes, fibroblasts, melanocytes, macrophages and other skin immune cells) express the vitamin D receptor (VDR), an absolute pre-requisite for exerting genomic effects of 1,25(OH)₂D₃ and analogs. The VDR is a member of the superfamily of trans-acting transcriptional regulatory factors, which also contains the steroid and thyroid hormone receptors as well as the retinoid-X receptors (RXR) and retinoic acid receptors (RAR). A large body of evidence, including cDNA microarray analyses of mRNAs, indicates that as many as 500-1000 genes may be controlled by VDR ligands that regulate a broad variety of cellular functions including growth, differentiation, and apoptosis. Clinical and laboratory investigations, including the observation that 1,25(OH)₂D₃ is very effective in inducing the terminal differentiation and in inhibiting the proliferation of cultured human keratinocytes have resulted in the use of 1,25(OH)₂D₃ and analogs for the treatment of psoriasis. Focussing on the UV-induced cutaneous synthesis of vitamin D, this review gives an update on the relevance of the VDES and of UV radiation for the management of psoriasis and other inflammatory skin diseases.

Targeting the vitamin D endocrine system (VDES) for the management of inflammatory and malignant skin diseases: An historical view and outlook

Vitamin D represents one of the major driving factors for the development of life on earth and for human evolution. While up to 10-20 % of the human organism's requirements in vitamin D can be obtained by the diet (under most living conditions in the USA and Europe), approximately 90 % of all needed vitamin D has to be photosynthesized in the skin through the action of the sun (ultraviolet-B (UV-B)). The skin represents a key organ of the human body's vitamin D endocrine system (VDES), being both the site of vitamin D synthesis and a target tissue for biologically active vitamin D metabolites. It was shown that human keratinocytes possess the enzymatic machinery (CYP27B1) for the synthesis of the biologically most active natural vitamin D metabolite 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃), representing an autonomous vitamin D₃ pathway. Cutaneous production of 1,25(OH)₂D₃ may exert intracrine, autocrine, and paracrine effects on keratinocytes and on neighboring cells. Many skin cells (including keratinocytes, sebocytes, fibroblasts, melanocytes, and skin immune cells) express the vitamin D receptor (VDR), an absolute pre-requisite for the mediation of genomic effects of 1,25(OH)₂D₃ and analogs. VDR belongs to the superfamily of trans-acting transcriptional regulatory factors, which includes the steroid and thyroid hormone receptors as well as the retinoid X receptors (RXR) and retinoic acid receptors (RAR). Numerous studies, including cDNA microarray analyses of messenger RNAs (mRNAs), indicate that as many as 500-1000 genes may be regulated by VDR ligands that control various cellular functions including growth, differentiation, and apoptosis. The observation that 1,25(OH)₂D₃ is extremely effective in inducing the terminal differentiation and in inhibiting the proliferation of cultured human keratinocytes has resulted in the use of vitamin D analogs for the treatment of psoriasis. This review gives an historical view and summarizes our present knowledge about the relevance of the VDES for the management of inflammatory and malignant skin diseases.

Studying the calcium serum level in patients suffering from psoriasis

The recent success of vitamin D and its analogues in the treatment of psoriasis has generated extensive research into the role of vitamin D and calcium in this hyperproliferative skin disease. This study aimed at studying the calcium serum level in patients suffering from psoriasis. In this case control studies, 98 hospitalized cases with psoriasis were compared with 100 patients who were hospitalized due to other diseases. Two groups were matched for age and gender. The type of psoriasis, age and sex of patients and serum calcium and albumin levels in two groups were documented in a especial questionnaire. Of all 98 patients with psoriasis, 37.2% were hypocalcemic and 63.7% had normal serum calcium. There was no hypercalcemia. In other group 9% were hypocalcemic, 89 and 2% were normocalcemic and hypercalcemic respectively. In 64.9% of hypocalcemic psoriatic patients, low serum albumin was noted. But all of control group had normal levels. Hypocalcemia is a risk factor of psoriasis. It is better to include dairy as calcium resource in daily diet of patients suffering from psoriasis.

Topical treatments for chronic plaque psoriasis

BACKGROUND

Chronic plaque psoriasis is the most common type of psoriasis, and it is characterised by redness, thickness, and scaling. First-line management of chronic plaque psoriasis is with topical treatments, including vitamin D analogues, topical corticosteroids, tar-based preparations, dithranol, salicylic acid, and topical retinoids.

OBJECTIVES

To compare the effectiveness, tolerability, and safety of topical treatments for chronic plaque psoriasis, relative to placebo, and to similarly compare vitamin D analogues (used alone or in combination) with other topical treatments.

SEARCH METHODS

We updated our searches of the following databases to February 2011: the Cochrane Skin Group Specialised Register, CENTRAL in The Cochrane Library (2011, Issue 2), MEDLINE (from 1948), EMBASE (from 1980), Science Citation Index (from 2008), Conference Proceedings Citation Index - Science (from 2008), BIOSIS (from 1993), Dissertation Abstracts via DialogClassic (all publication years), and Inside Conferences (all publication years).We identified ongoing and unpublished studies from the UK Clinical Research Network Study Portfolio and the metaRegister of Controlled Trials. We checked the bibliographies of published studies and reviews for further references to relevant trials, and we contacted trialists and companies for information about newly published studies.A separate search for adverse effects was undertaken in February 2011 using MEDLINE and EMBASE (from 2005).Final update searches for both RCTs and adverse effects were undertaken in August 2012. Although it has not been possible to incorporate RCTs and adverse effects studies identified through these final searches within this review, we will incorporate these into the next update.

SELECTION CRITERIA

Randomised trials comparing active topical treatments against placebo or against vitamin D analogues (used alone or in combination) in people with chronic plaque psoriasis.

DATA COLLECTION AND ANALYSIS

One author extracted study data and assessed study quality. A second author checked these data. We routinely contacted trialists and companies for missing data. We also extracted data on withdrawals and on local and systemic adverse events. We defined long-term trials as those with a duration of at least 24 weeks.

MAIN RESULTS

This update added 48 trials and provided evidence on 7 new active treatments. In total, the review included 177 randomised controlled trials, with 34,808 participants, including 26 trials of scalp psoriasis and 6 trials of inverse psoriasis, facial psoriasis, or both. The number of included studies counted by Review Manager (RevMan) is higher than these figures (190) because we entered each study reporting a placebo and an active comparison into the 'Characteristics of included studies' table as 2 studies.When used on the body, most vitamin D analogues were significantly more effective than placebo, with the standardised mean difference (SMD) ranging from -0.67 (95% CI -1.04 to -0.30; 1 study, 119 participants) for twice-daily becocalcidiol to SMD -1.66 (95% CI -2.66 to -0.67; 1 study, 11 participants) for once-daily paricalcitol. On a 6-point global improvement scale, these effects translate into 0.8 and 1.9 points, respectively. Most corticosteroids also performed better than placebo; potent corticosteroids (SMD -0.89; 95% CI -1.06 to -0.72; I² statistic = 65.1%; 14 studies, 2011 participants) had smaller benefits than very potent corticosteroids (SMD -1.56; 95% CI -1.87 to -1.26); I² statistic = 81.7%; 10 studies, 1264 participants). On a 6-point improvement scale, these benefits equate to 1.0 and 1.8 points, respectively. Dithranol, combined treatment with vitamin D/corticosteroid, and tazarotene all performed significantly better than placebo.Head-to-head comparisons of vitamin D for psoriasis of the body against potent or very potent corticosteroids had mixed findings. For both body and scalp psoriasis, combined treatment with vitamin D and corticosteroid performed significantly better than vitamin D alone or corticosteroid alone. Vitamin D generally performed better than coal tar, but findings relative to dithranol were mixed. When applied to psoriasis of the scalp, vitamin D was significantly less effective than both potent corticosteroids and very potent corticosteroids. Indirect evidence from placebo-controlled trials supported these findings.For both body and scalp psoriasis, potent corticosteroids were less likely than vitamin D to cause local adverse events, such as burning or irritation. Combined treatment with vitamin D/corticosteroid on either the body or the scalp was tolerated as well as potent corticosteroids, and significantly better than vitamin D alone. Only 25 trials assessed clinical cutaneous dermal atrophy; few cases were detected, but trials reported insufficient information to determine whether assessment methods were robust. Clinical measurements of dermal atrophy are insensitive and detect only the most severe cases. No comparison of topical agents found a significant difference in systemic adverse effects.

AUTHORS' CONCLUSIONS

Corticosteroids perform at least as well as vitamin D analogues, and they are associated with a lower incidence of local adverse events. However, for people with chronic plaque psoriasis receiving long-term treatment with corticosteroids, there remains a lack of evidence about the risk of skin dermal atrophy. Further research is required to inform long-term maintenance treatment and provide appropriate safety data.

[Hungarian consensus regarding the role of vitamin D in the prevention and treatment of diseases]

The metabolism of vitamin D is unique in the human body and its diverse effects are present in almost every organ. Vitamin D deficiency is one of the most prominent health issues in the civilized world. For the solution of this concern an extensive collaboration is imperative. Recognizing this necessity the most prominent Hungarian medical associations fighting with the effects of vitamin D deficiency worked out a collective consensus on the importance, diagnosis, prevention and suggested therapy of vitamin D deficiency. Along with the clinical guidelines of the different associations, the result of this consensus could serve as guidance for the practicing doctors in the prevention and therapy of vitamin D deficiency. In addition the consensus aims to direct the attention of decision-makers and the general public on the significance of this issue.

Vitamin D analogs in the treatment of psoriasis: Where are we standing and where will we be going?

Vitamin D and analogs exert in the skin and other tissues potent effects on cellular differentiation and proliferation. Moreover, these compounds regulate apoptosis and exert immunomodulatory effects. During the last decades, it has convincingly been shown that vitamin D compounds are effective and safe in the topical treatment of psoriasis, where they nowadays represent a standard therapy. This review summarizes laboratory and clinical investigations related to the treatment of psoriasis with calcitriol or analogs. Additionally, promising concepts for the development of new vitamin D analogs are discussed. As a matter of fact, the final goal to create strong antiproliferative or antiinflammatory acting vitamin D analogs that exert only minor calcemic activity has not been reached until today. New agents that may activate selective vitamin D signalling pathways but may exert only negligible calcemic activity would declare a new era in dermatologic therapy and may also be effective in the topical or systemic treatment of various inflammatory skin diseases including atopic dermatitis and in various cutaneous malignancies, including lymphomas, squamous cell carcinoma or basal cell carcinoma.

Topical treatments for chronic plaque psoriasis

BACKGROUND

Chronic plaque psoriasis is the most common type of psoriasis and is characterised by redness, thickness and scaling. First line management of chronic plaque psoriasis is with topical treatments, including vitamin D analogues, topical corticosteroids, tar-based preparations, dithranol, salicylic acid and topical retinoids.

OBJECTIVES

To compare the effectiveness, tolerability and safety of topical treatments for chronic plaque psoriasis with placebo; to compare vitamin D analogues with other topical treatments.

SEARCH STRATEGY

The Cochrane Skin Group's Trials Register was searched (2004/12). To update an unpublished 2002 review we also searched CENTRAL in The Cochrane Library (Issue 1,2005); MEDLINE (to 2005/02); EMBASE (to 2005/08); Science Citation Index (to 2005); Biosis (to 2005); Dissertation Abstracts (all publication years); Inside Conferences (all publication years); SIGLE (to 2005); National Research Register (all projects with a start date of 2001 to 2005); metaRegister of Current Controlled Trials.

SELECTION CRITERIA

Randomised trials comparing treatments against placebo or against vitamin D analogues in people with chronic plaque psoriasis.

DATA COLLECTION AND ANALYSIS

One author extracted study data and assessed study quality. A second author checked these data. We routinely contacted triallists and companies for missing data. We extracted data on withdrawals and adverse events.

MAIN RESULTS

The review included 131 RCTs with 21,448 participants. Vitamin D was significantly more effective than placebo, although there was a wide variation in effect size with the standardised mean difference (SMD) ranging from -0.82 (95% CI -1.34 to -0.29) to -1.90 (95% CI -2.09 to -1.71). With one exception, all corticosteroids performed better than placebo, with potent corticosteroids (SMD: -0.95 (95% CI: -1.11 to -0.80; I(2): 61.1%; 17 studies; 2386 participants)) having smaller benefits than very potent corticosteroids (SMD: -1.29 (95% CI: -1.45 to -1.13; I(2): 53.2%; 11 studies; 1571 participants)). Dithranol and tazarotene performed better than placebo. Head-to-head comparisons of vitamin D against potent or very potent corticosteroids found no significant differences. However, combined treatment with vitamin D /corticosteroid performed significantly better than either vitamin D alone or corticosteroid alone. Vitamin D performed better than coal tar, but findings relative to dithranol were mixed. Potent corticosteroids were less likely than vitamin D to cause local adverse events. No comparison of topical agents found a significant difference in systemic adverse effects.

AUTHORS' CONCLUSIONS

Corticosteroids perform as well as vitamin D analogues and are associated with a lower incidence of local adverse events. Further research is required to inform long-term maintenance treatment.

Topical paricalcitol (19-nor-1 alpha,25-dihydroxyvitamin D2) is a novel, safe and effective treatment for plaque psoriasis: a pilot study

BACKGROUND

There continues to be a need to develop new pharmacological approaches for treating psoriasis. Topical active vitamin D compounds have proven to be both safe and effective for treating psoriasis. Paricalcitol (19-nor-1 alpha,25-dihydroxyvitamin D(2)) is a novel vitamin D analogue which has been developed for the prevention of secondary hyperparathyroidism in patients with chronic renal failure.

OBJECTIVES

To investigate the efficacy and safety of 12 weeks' therapy with a once-daily application of paricalcitol ointment (15 microg g(-1)) in comparison with placebo ointment.

METHODS

This pilot double-blinded self-controlled study was initiated in 11 patients with moderate plaque psoriasis. To characterize the biological effects further and to evaluate the efficacy of topical paricalcitol treatment in psoriasis, we have analysed immunohistochemically the expression of one of the markers for epidermal differentiation (transglutaminase K) in paricalcitol-treated skin as compared with placebo treatment.

RESULTS

Treatment with paricalcitol was superior to placebo treatment beginning at week 1. The global severity score for erythema, plaque elevation and scaling was improved significantly more by paricalcitol ointment than by placebo (P < 0.001). Similar results were obtained for assessments of scaling, erythema and plaque elevation. No symptoms of local skin irritation were noted. Laboratory parameters including serum calcium, phosphorus, parathyroid hormone and urinary calcium/creatinine ratio did not reveal any changes of clinical relevance during treatment. The immunoreactivity of transglutaminase K changed after 12 weeks of paricalcitol treatment almost completely to the pattern characteristic for nonlesional psoriatic skin.

CONCLUSIONS

Once-daily application of paricalcitol ointment was safe and effective for the treatment of plaque psoriasis.

Topical PTH (1-34) is a novel, safe and effective treatment for psoriasis: a randomized self-controlled trial and an open trial

BACKGROUND

There continues to be a need to develop new pharmacological approaches for treating the common skin disease psoriasis. Human skin produces parathyroid hormone related peptide. This peptide is a potent inhibitor of epidermal cell growth.

OBJECTIVES

A programme was initiated to determine whether an agonist of this peptide's receptor, PTH (1-34), could be developed as a drug to treat psoriasis.

METHODS

PTH (1-34) was formulated in Novasome A cream. Fifteen adult patients with chronic plaque psoriasis who had failed to respond to at least one standard treatment were enrolled in a randomized double-blinded placebo self-controlled trial. The patients topically applied to a 25-cm2 psoriatic lesion 0.1 g of either Novasome A cream or Novasome A cream that contained 20 microg of PTH (1-34) twice a day for 2 months. At the end of the double-blind study, patients were enrolled in an open large area study. Ten patients applied PTH (1-34) (50 microg per 0.1 g) once daily to their psoriatic lesions. The patients were evaluated for their global improvement and calcium metabolism.

RESULTS

Novasome A cream enhanced the percutaneous absorption of PTH (1-34) in human skin in comparison with formulations in propylene glycol or normal saline. Psoriatic lesions treated with PTH (1-34) showed marked improvement in scaling, erythema and induration. There was a 67.3% improvement in the global severity score for the lesion treated with PTH (1-34) compared with the placebo-treated lesion, which only showed a 17.8% improvement. Ten patients topically applied PTH (1-34) on all of their lesions in a stepwise manner. A Psoriasis Area and Severity Index score analysis of all the patients revealed improvement of 42.6% (P < 0.02). None of the patients experienced hypercalcaemia or hypercalciuria or developed any side-effect to the medication.

CONCLUSIONS

Patients who were resistant to at least one standard therapy for psoriasis had a remarkable improvement in their psoriasis when they applied PTH (1-34) to their lesion(s). No untoward toxicity was observed in any of the subjects. This pilot study suggests that topical PTH (1-34) is a safe and effective novel therapy for psoriasis.

Vitamin D and the skin

Vitamin D was originally discovered as a factor that regulates calcium and bone metabolism. Recent advances in investigation have shown that vitamin D also functions as a regulator of cellular growth and differentiation in various tissues. The skin is not an exception from such effects of vitamin D; it is regarded as a site of its activation and action. Evidence has accumulated showing that the active form of vitamin D and its analogs suppress growth and stimulate the terminal differentiation of keratinocytes. In psoriatic lesions, epidermal keratinocytes exhibit hyper-proliferation and impaired differentiation triggered by inflammation. Therefore, it is quite reasonable that vitamin D is effective on psoriasis. Indeed, within the past decade, analogs of vitamin D3 have been used as topical therapy for psoriasis. In this review, we summarize the fundamental features of vitamin D and the development of vitamin D therapy for psoriasis. Clinical application to other skin diseases and the future of vitamin D therapy in dermatology are also discussed.

An update on the therapeutic potential of vitamin D analogues

The review provides an evaluation of the therapeutic potential of vitamin D analogues in the context of the current understanding of vitamin D biochemistry, molecular biology and physiology. Vitamin D activity results from several circulating and intracellular physiological metabolites acting simultaneously through at least three receptors. Common analogues are reviewed. Although most vitamin D analogues have traditionally been analogues of 1,25-dihydroxyvitamin D, it may be better to deliver high doses of base vitamin or (analogues) of 25-hydroxyvitamin D. This would permit physiological endocrine, paracrine and autocrine vitamin D metabolism. Agonists or antagonists of tissue-specific vitamin D metabolic pathways could be coadministered. The importance of measuring endogenous vitamin D metabolites during in vivo studies and the pitfalls of extending data across species and time are emphasised. Human vitamin D analogue trials should include direct comparison against the related endogenous metabolite.