Distribution of skin-derived antileucoproteases (SKALP) in the marginal zone of the spreading psoriatic lesion

Two new elastase inhibitors (SKALP, skin-derived antileucoproteases) were recently described in the lesional skin in psoriasis. The present study investigated the distribution of SKALP activity in the marginal zone of spreading psoriatic plaques. In a 4-mm zone immediately adjacent to the erythemato-squamous plaques, SKALP activity was slightly increased compared to distant uninvolved skin. Within the lesion the anti-elastase activity was pronounced, but was significantly higher in the central zone of the plaque compared to the periphery. The appearance of SKALP in the psoriatic lesion appears to be a late event compared to endothelial involvement, intraepidermal accumulation of PMNs, epidermal proliferation and abnormal keratinization. This observation lends further support for the hypothesis that the induction of anti-elastase activity is associated with the off-switch of cutaneous inflammation.     

Phorbol ester decreases cytosolic retinoic acid binding protein (CRABP) capacity in normal but not psoriatic epidermis

The retinoic acid binding protein (CRABP) characterized in human epidermal cytosol exhibits a three-fold increased binding capacity in lesional psoriatic epidermis as compared to normal or uninvolved skin. Treatment of epidermal homogenate from normal subjects by phorbol ester + ATP decreases the specific binding capacity of CRABP without affecting its dissociation constant (Kd=10 nM). The same effect was not observed in involved and uninvolved psoriatic epidermis. These results could be related to the previously reported decreased protein kinase C activity in psoriatic skin. They also suggest that posttranslational events could be responsible for pathological and pharmacological variations in CRABP binding capacity.     

Lack of upregulation of epidermal fatty acid binding protein in dithranol induced irritation

The exact role of epidermal fatty acid binding protein (E-FABP) in skin is unknown. A restoration of the barrier function may be associated with an upregulation of E-FABP. Moreover, E-FABP is upregulated in a variety of cells in response to oxidative stress. A recent observation that dithranol induced irritation is not associated with skin barrier impairment prompted us to investigate the expression of E-FABP in this skin condition to elucidate the unknown function of this protein in skin. This study shows lack of E-FABP upregulation after a single application of dithranol on uninvolved skin of patients with psoriasis. The expression of E-FABP in dithranol irritation correlates with the unimpaired skin barrier function as assessed by measurements of TEWL. Furthermore, we did not find evidence for the recently introduced hypothesis that E-FABP functions as an antioxidant protein in the skin irritation induced by dithranol as oxidative stressor.     

Oral liarozole vs. acitretin in the treatment of ichthyosis: a phase II/III multicentre, double-blind, randomized, active-controlled study

BACKGROUND: Liarozole, a retinoic acid metabolism blocking agent, has been granted orphan drug status for congenital ichthyosis by the European Commission and the U.S. Food and Drug Administration. OBJECTIVES: The purpose of this trial was to investigate the efficacy, tolerability and safety of oral liarozole vs. acitretin in patients with ichthyosis. METHODS: In this double-blind comparative trial of liarozole vs. acitretin, 32 patients with ichthyosis were randomized to be treated with either oral liarozole 75 mg in the morning and 75 mg in the evening or with acitretin 10 mg in the morning and 25 mg in the evening for 12 weeks. Clinical efficacy, tolerability and safety were monitored. RESULTS: Between-group comparisons for efficacy and tolerability revealed no statistically significant differences except for scaling on the trunk at baseline which was significantly worse in the liarozole group (P = 0.024) and showed a more pronounced improvement in this group than in the acitretin-treated patients (P = 0.047). Based on the overall evaluation of the response to treatment at endpoint, 10 of 15 patients in the liarozole group and 13 of 16 patients in the acitretin group were considered by the investigator to be at least markedly improved. The expected retinoic acid-related adverse events were mostly mild to moderate and tended to occur less frequently in the liarozole group. No serious adverse events related to the drugs occurred. CONCLUSIONS: The present study indicates that liarozole at a daily dose of 150 mg is equally effective as a treatment for ichthyosis as acitretin but shows a trend towards a more favourable tolerability profile. The results of this trial warrant further clinical trials to confirm efficacy and safety of liarozole as an orphan drug in ichthyosis.     

UV-induced isomerization of oral retinoids in vitro and in vivo in hairless mice

Ultraviolet (UV) irradiation causes isomerization and destruction of many vitamin A analogues (retinoids). Using high-performance liquid chromatography (HPLC), we investigated in vitro and in vivo the effects of UV irradiation on 2 all-trans aromatic retinoids (etretinate and acitretin) and on 13-cis retinoic acid (isotretinoin). When etretinate and acitretin dissolved in ethanol were irradiated with UVB (280-320 nm; 10-336 mJ/cm2) or UVA (320-400 nm; 1-5 J/cm2), extensive and reproducible cis-isomerizations occurred at the 13-position (cis/trans ratio approximately 1.6 in all experiments) but there was no progressive photodegradation of the molecules. Irradiation of isotretinoin produced only moderate trans-isomerization but the sum of HPLC peak heights fell with increasing UV doses, being 72% of the original value after 336 mJ/cm2 of UVB. Hairless mice were given etretinate (50 mg/kg bw), acitretin (200 mg/kg) or isotretinoin (50 mg/kg) on days 1, 4 and 7 and were irradiated daily for 8 d with 13 mJ/cm2 UVB plus 1 J/cm2 UVA. Samples of serum, dorsal skin and liver were collected and retinoids analyzed by HPLC. In the etretinate and acitretin-treated, irradiated animals the serum concentrations of the 13-cis isomers were 2-6 times higher than in nonirradiated controls. Irradiated epidermis also contained significantly higher concentrations of 13-cis etretinate and 13-cis acitretin than did control epidermis. The serum and epidermal concentrations of all-trans etretinate and acitretin were unchanged or even increased after irradiation.(ABSTRACT TRUNCATED AT 250 WORDS)     

银屑病皮损区和非皮损区AgNOR的定量观察

应用核仁组成区银染蛋白（ＡｇＮＯＲ）染色方法，对１２例银屑病患者皮损区和非皮损区表皮细胞进行了观察。并和非银屑病患考的正常皮肤及慢性皮炎类皮损各１２例进行了比较。结果显示银屑病患者皮损区和非皮损区ＡｇＮＯＲ值均数均明显高于正常皮肤和慢性皮炎类皮损，而后两者相类似。作者认为ＡｇＮＯＲ在组织学上可能有助于银屑病和一些慢性皮炎类疾病的鉴别。     

Psoriasis vulgaris--unchanged endothelial reactivity with histochemical markers

Frozen sections from psoriatic lesions were investigated regarding their reactivity with endothelial markers (UEA I, EEA I, LTA, Con A, factor VIII-related antigen). We compared the findings obtained with those of both uninvolved psoriatic skin and normal skin. Although all lectins showed altered epidermal binding in comparison to the controls, the endothelial lectin binding as well as the expression of factor VIII-related antigen were the same in both psoriatric lesions and controls. Our findings argue for (1) intact dimorphic genetic control of ABH expression in both epidermal and endothelial cells, (2) altered epidermal differentiation of lesional psoriatric skin, and (3) secondary vascular alterations.     

Differential expression of CRABP II,psoriasin and cytokeratin 1 mRNA in human skin diseases

In order to confirm and further explore the significance of the overexpression of the CRABP II (cellular retinoic acid binding protein type II) and psoriasin genes in psoriatic versus normal skin, we examined the mRNA expression levels of these two genes by in situ hybridization in skin samples from psoriatic plaques and in one case from the border between a psoriatic plaque and uninvolved skin. Both genes were markedly upregulated in lesional skin, with a shift from low to high expression in the transitional zone of the plaque. Expression of the cytokeratin 1 (K1) gene was, in contrast, high in normal skin and decreased in the transition from uninvolved skin to psoriatic plaque, Examination of mRNA levels of CRABP II and psoriasin in other hyperproliferative and inflammatory skin diseases showed high expression of psoriasin, and in some cases also of CRABP II, in atopic dermatitis, mycosis fungoides, Darier’s disease and inflammatory lichen sclerosus et atrophicus. In atrophic lesions of lichen sclerosus et atrophicus that lacked an inflammatory infiltrate, these changes were only weakly expressed. These findings demonstrate that altered epidermal gene expression of K1, psoriasin and CRABP II is not disease-specific and may reflect instead an altered state of epidermal differentiation and/or may be linked to the inflammation and cellular infiltration common to all the conditions studied.     

Darier''s disease: an immunohistochemical study using monoclonal antibodies to human cytokeratins

The pathogenesis of Darier's disease was investigated by immunohistochemical staining of skin biopsies from involved and uninvolved skin in 14 patients, using monoclonal antibodies specific for keratins expressed in simple epithelia, stratified squamous epithelia and during skin specific differentiation as well as keratins expressed in mucosa and some benign epidermal hyperproliferative states. Uninvolved perilesional skin from Darier's patients showed a normal profile of keratin expression, whereas in lesional skin there was apparent delay in the expression of the suprabasal skin specific keratins. Suprabasal keratins were not detected in basal cells, thus there was no true premature keratinization. The presence of hyperproliferative keratins was restricted to suprabasal cells in lesional skin. Four patients were receiving treatment with etretinate at the time of biopsy, but results in these patients did not differ from patients using topical treatments. Etretinate did not influence the profile of keratin expression in uninvolved or involved skin. The expression of type VII collagen was examined and was normal throughout uninvolved and lesional skin in Darier's disease.     

Simple assays of retinoid activity as potential screens for compounds that may be useful in treatment of psoriasis.

Human epidermal cell cultures were used to study the effects of retinoids on keratinocyte differentiation. Keratin profiles were studied by quantitative gel electrophoresis of culture extracts, whereas the extent of envelope formation was assessed in an enzyme-linked immunosorbent assay (ELISA) using an antibody that specifically recognizes keratinocyte envelopes. Exposure of cultures to a variety of different retinoids produced both dose-dependent decreases in keratin 16 with consequent increases in the keratin 14: keratin 16 ratio, and a decrease in envelope formation. The order of activity in both assays was similar: arotinoid ethyl ester (Ro 13-6298) greater than or equal to arotinoid acid (Ro 13-7410) much greater than all trans retinoic acid (Ro 1-5488) greater than acitretin (Ro 10-1670) greater than or equal to etretinate (Ro 10-9359), the only difference being that acitretin was slightly more active than etretinate in the keratin assay whereas these retinoids were equi-active in the envelope assay. Analysis of the lesional keratins of psoriasis patients showed that etretinate caused a reduction in keratin 16 and an increase in the keratin 14:keratin 16 ratio, although the magnitude of these changes and their correlation with clinical improvement was variable. As the in vitro assays reported here are simple and quick, they allow rapid screening of compounds for retinoid-like activity.     

Interleukin-6 in the epidermis of patients with psoriasis before and during PUVA treatment

Biopsies from lesional and unaffected skin of 6 patients with psoriasis, taken before and during treatment with psoralen plus UVA (PUVA) were examined immunohistologically, using partially purified polyclonal antibodies to crude supernatants of activated human blood monocytes. By absorption with recombinant derived human monokines, we were able to demonstrate that interleukin-6 (IL-6) (but not IL-1 alpha or IL-1 beta) was located in a laminar and granular pattern in stratum corneum, and on epidermal cell membranes in the viable cellular epidermis. Before PUVA treatment, the intensity and the extension of staining for IL-6 were both markedly increased in lesional skin compared with uninvolved skin. A weaker staining for IL-6 was observed in lesional skin, simultaneous with the clinical improvement of psoriasis. The staining patterns for IL-6 in biopsies from cleared lesional skin and uninvolved psoriatic skin were identical at the conclusion of therapy.     

TNF-α and serum induce SKALP/elafin gene expression in human keratinocytes by a p38 MAP kinase-dependent pathway

Keratinocytes of inflamed epidermis (psoriasis, wound healing) are hyperproliferative and display an abnormal differentiation programme. This regenerative differentiation pathway is characterized by the induction of genes that are not expressed by keratinocytes in normal skin, such as the cytokeratins CK6, CK16, CK17, and the proteinase inhibitor SKALP/elafin. In the study reported here we investigated the induction and regulation of SKALP expression as a marker for regenerative differentiation in epidermal keratinocytes. Various cytokines and growth factors known to be present in psoriatic epidermis were examined for their ability to induce SKALP gene expression in cultured human keratinocytes. Tumour necrosis factor-alpha (TNF-alpha) and serum were found to be potent inducers of SKALP expression at both the mRNA and the protein levels. SB202190 or SB203580, two specific p38 MAP kinase inhibitors almost completely blocked the induction of SKALP expression by TNF-alpha and serum. These results suggest that in keratinocytes, p38 activity is crucial for the induction of SKALP gene expression. These findings could be relevant for the elucidation of the mechanisms involved in normal and disturbed epidermal differentiation.     

Exploration of retinoid activity and the role of inflammation in acne: issues affecting future directions for acne therapy

The review summarizes new results concerned with several important issues in the treatment of patients with acne. The first section reviews studies which show that 13- cis retinoic acid, a molecule with strong biological activity but low binding affinity for retinoid receptors and cellular-binding proteins in sebocytes, undergoes rapid intracellular conversion to all- trans retinoic acid. This active metabolite exerts its actions on sebocyte gene expression by binding to the nuclear retinoic acid receptor rather than the retinoid X receptor. Importantly, 13- cis retinoic acid, unlike all- trans retinoic acid, does not induce cytochrome P450 1A1, an enzyme responsible for the metabolism of xenobiotics. Thus, administration of 13- cis retinoic acid permits high long-term intracellular accumulation of its active metabolite. The second section reviews studies which suggest that leukotriene B4 may play a key role in acne-related inflammation. Results from a preliminary clinical study indicate that therapy with a specific lipoxygenase inhibitor is clinically effective in the treatment of patients with inflammatory acne and that its clinical efficacy is correlated with the drug's ability to reduce total lipid levels, and especially pro-inflammatory lipids, in sebum. Interestingly, 13- cis retinoic acid has been shown to modulate the activities of LTB4 and inflammatory events in the development of acne. Therefore, future compounds targeting acne have to inhibit pro-inflammatory lipids in sebum, and thus down-regulate acne-related inflammatory signals and reduce the LTB4-induced migration of inflammatory cells.     

Oral treatment of ichthyosis by the cytochrome P-450 inhibitor liarozole

Liarozole, a novel imidazole derivative, inhibits the cytochrome P450-dependent 4-hydroxylation of retinoic acid. resulting in increased tissue levels of retinoic acid. Twelsve male patients with ichthyosis were given oral liarozole. 150mg twice daily. in an open study for 12 weeks. Immunohistochemical parameters of inflammation, epidermal proliferation and differentiation were assessed before and after treatment. Extent and severity of the skin lesions was markedly reduced in all prtients. Clinical side-effects were reminiscent of those with synthetic retinoids. No relevant changes were found in the haematological. urinary and biochemical parameters. Immunohistochemical assessment showed a statistically significant induction of keratin 4 after liarozole treatment in 10 of 12 patients. In two of these patients keratin 13 was induced. This open study showed that oral liarozole treatment was efficacious and well tolerated in the treatment of different types of ichthyosis. The immunohisotchemical results suggest a retinoid mechanism as the mode of action.     

Skin-derived antileukoproteinase (SKALP) is decreased in pustular forms of psoriasis. A clue to the pathogenesis of pustule formation?

Skin-derived antileukoproteinase (SKALP, also known as elafin) is an inducible epidermal serine proteinase inhibitor, that we have recently characterized at the protein and DNA levels. SKALP is a strong and specific inhibitor of PMN elastase, and is putatively involved in the regulation of cutaneous inflammatory processes. In order to investigate the role of SKALP in the control of elastase in psoriatic epidermis, we compared SKALP expression in normal skin, and in skin from patients with chronic plaque psoriasis and pustular forms of psoriasis. Epidermal scales and biopsies were collected and SKALP expression was studied at the mRNA level and at the protein level both functionally and immunochemically. In epidermal scales, we found that the levels of both free and total SKALP activity in pustular psoriasis were far lower than in plaque psoriasis. A significant number of pustular psoriasis patients showed latent SKALP activity, which represents the amount of SKALP putatively complexed to elastase. In addition, we found free elastase activity in 25% of the pustular psoriasis patients, indicating a total saturation of epidermal SKALP activity. In epidermal biopsies from pustular psoriasis patients, SKALP activity was significantly decreased compared with those from plaque psoriasis patients. Northern blot analysis did not reveal differences in epidermal mRNA levels between chronic plaque psoriasis and pustular psoriasis. We hypothesize that a reduced amount of epidermal SKALP contributes to an imbalance between elastase and its inhibitor, thereby promoting the formation of epidermal pustules. We suggest that these findings could provide a rationale for the treatment of pustular psoriasis with inhibitors of PMN-derived proteinases, as a new therapeutic modality. Received: 27 November 1995     

The usefulness of reflectance spectrophotometric measurements during psoralens and ultraviolet A therapy for psoriasis

Reflectance spectrophotometry was used to obtain indices of the hemoglobin and melanin content of psoriatic lesions and adjacent clinically normal skin in thirteen patients undergoing photochemotherapy. The pretreatment lesional hemoglobin index was 2.8 times greater than that of adjacent uninvolved skin. With therapy, this index decreased rapidly initially, and during the second or third week approached that of the uninvolved skin. The ratio of lesional and uninvolved skin hemoglobin indices decreased to approximately 1.3, and continuation of PUVA treatment failed to reduce it further. Termination of treatment at this stage, which occurs before clinical resolution, resulted in subsequent clearance of psoriasis. The decrease in the lesional hemoglobin index and the clearance time appeared to be dose-dependent, and, indeed, a more aggressive regimen resulted in approximately 50% reduction in both the number of treatments and the cumulative dose required to achieve a stable hemoglobin index ratio and subsequent clinical clearance.     

Changes in keratinocyte differentiation following mild irritation by sodium dodecyl sulphate

Although the induction of acute irritant dermatitis by detergents has been studied extensively in recent years, our understanding of the cell biological events in the repair phase, and its relevance for the development of chronic irritant dermatitis is limited. Here we studied the reaction pattern of human skin to short-term application of sodium dodecyl sulphate (SDS) in a model that induced a minimal acute inflammatory reaction (absence of polymorphonuclear leucocytes, PMN) and did not have cytopathic effects on the epidermal keratinocytes as determined by histological investigation. All parameters were measured up to 14 days after exposure to SDS. Application of SDS caused disturbances of barrier function as measured by transepidermal water loss and had vascular effects as judged by erythema. Several cell biological markers for epidermal growth and differentiation were examined by immunohistochemistry. A rapid and strong induction of the cornified envelope precursor protein involucrin was seen in the stratum spinosum, with a peak at 24 h. Within 24 h a strong upregulation of epidermal fatty acid binding protein (E-FABP) was noted, with a peak at 7 days after injury. Cellular proliferation in the basal layer was increased fivefold as assessed by nuclear staining for the Ki-67 antigen, showing a peak at 48 h. Surprisingly, no significant induction of cytokeratin 16 and SKALP/elafin expression, two markers associated with epidermal hyperproliferation and inflammation, was seen. These findings suggest that the cellular changes following exposure to detergent are distinct from those seen in other forms of skin injury. We would speculate that the epidermal response to detergent exposure is primarily directed at restoration of barrier function. Received: 30 October 1995     

The release of leukotriene B4-like material in biologically active amounts from the lesional skin of patients with psoriasis

The 5,12-dihydroxy metabolite of arachidonic acid, leukotriene B4, is a highly potent neutrophil chemoattractant. In view of the characteristic epidermal neutrophil infiltrate in psoriasis, the presence of leukotriene B4 in samples from untreated lesional and uninvolved skin has been sought. Chambers were fixed to abraded skin and filled with phosphate-buffered saline (PBS). After 35 min, the fluid was removed, and acidic lipids were extracted and subjected to high-performance liquid chromatography (HPLC). Extracts were purified by both straight- and reversed-phase HPLC, and assay of evaporated fractions by an agarose microdroplet chemokinesis technique indicated the presence of leukotriene B4-like material. No significant leukotriene B4-like activity was found in samples from uninvolved skin. Subsequent experiments using a modification of the initial skin chamber method indicated that leukotriene B4 was being released from deeper layers of lesional skin and not only from superficial scale. Monohydroxy-eicosatetraenoic acid-like activity was also seen in lesional samples as determined by straight-phase HPLC and chemokinesis assay. These findings and the proinflammatory properties of these compounds in human skin suggest that they may play a role in the pathogenesis of the psoriatic neutrophil infiltrate.