1α,25(OH)2 vitamin D3 increases intracellular calcium in human keratinocytes

Vitamin D3 metabolites have been found to improve psoriasis but their mechanism of action is not clear. Keratinocyte proliferation and differentiation are known to be dependent on calcium concentrations in vitro. The aim of this study was to examine whether 1 alpha,25(OH)2 vitamin D3 had any direct effect on intracellular free calcium concentrations in cultured keratinocytes. A response to 1 alpha,25(OH)2 vitamin D3 was seen in 88% of monolayers of normal human keratinocytes attached to glass coverslips. An increase in intracellular free calcium was seen in 80% of the reactive cultures, with over half the responses occurring within 30 s of exposure to 1 alpha,25(OH)2 vitamin D3 and the remainder occurring within minutes. Responses could be seen at physiological concentrations of 1 alpha,25(OH)2 vitamin D3 and were not blocked by the protein synthesis inhibitor cycloheximide. The response to 1 alpha,25(OH)2 vitamin D3 took the form of rapid transient increases in intracellular free calcium in 29 out of 59 coverslips. The basal intracellular free calcium was calculated to be 245 +/- 47 nM rising to a maximum of 834 +/- 267 nM (mean +/- SEM; n = 20) following exposure to 1 alpha,25(OH)2 vitamin D3. We conclude that 1 alpha,25(OH)2 vitamin D3 acts directly on keratinocytes to increase intracellular free calcium and that this may be relevant to its mechanism of action in psoriasis.     

Decreased expression of α2β1 integrin in scleroderma fibroblasts

Abstract Systemic scleroderma (SSc) is a complex connective tissue disorder of unknown etiology. In early stages of the disease, libroblasts are activated to produce large amounts of collagen with subsequent fibrosis. Collagen metabolism of fibroblasts is modulated by their contact with the extracellular matrix (ECM), which involves distinct receptors on the cell surface, mainly belonging to the integrins. We investigated the expression of collagen receptor α₂β₁, in SSc and normal fibroblasts, since this receptor has been shown to be utilized by fibroblasts for adhesion to and reorganization of collagen I. 9 strains of scleroderma fibroblasts grown as monolayer cultures were first analyzed with respect to their collagen I expression. 6 of these strains were similar to controls (“low” producers) and 3 strains showed up to 2–3 × higher levels of collagen I mRNA expression (“high” producers). Northern hybridization using a cDNA probe specific for the α₂ integrin subunit revealed a decrease of the corresponding mRNA in SSc fibroblasts as compared to controls (75% versus 100%). “High” collagen producing cell strains displayed the lowest values for α₂ integrin mRNA. The decrease of α₂ integrin subunit expression at the mRNA level in selected fibroblasts was further substantiated by radioimmunoprecipitation using specific mAbs directed against α₂ integrin subunit. No significant changes in β₁ integrin expression could be observed-neither at mRNA nor at the protein level. Our data indicate a correlation between excessive synthesis of collagen and low levels of α₂ integrin subunit expression in SSc fibroblasts. Further experiments should clarify whether this observation is a phenomenon specific for scleroderma or whether it reflects an “activated” state of fibroblasts.     

α1-Antitrypsin Deficiency and Skin Abnormalities

A 19-year-old Moroccan male was found to have total absence of serum alpha₁-antitrypsin, a major inhibitor of elastase. This patient had chronic obstructive lung disease, hyperextensibility of the skin over the cheeks and wrists, and hyperlaxity of the hand joints. Microscopic sections of the skin revealed a thickened dermis with shortened and rarefied clastic fibers. Ultrastructural study showed collagen fibers with variable and irregular diameters. Elastic fibers were scarce and their relatively poor matrix was surrounded by numerous microfibrils. The outline of the fibers was irregular with deep recesses filled with microfibrils. The ergastoplasm of the fibroblasts was well developed. The differential diagnosis with other connective dystrophies showed the original characteristic of this case. Clinically and histopathologically, the skin abnormalities are probably related to the deficiency in elastase inhibitor.     

α1-Antitrypsin deficiency in severe psoriasis

alpha 1-Antitrypsin phenotypes and trypsin-inhibitory capacities were measured in fifty-one patients with psoriasis. An increased number of variant phenotypes (MS, MZ, and SS) were found only in those patients with severe psoriasis (20% or more skin involvement) and not in those with lesser involvement. The psoriatic patients with variant phenotypes had an earlier disease onset than those psoriatic individuals (both mild and severe) without this association. Protease inhibitors may play a role in modifying disease activity in psoriasis.     

The effect of tacalcitol (1,24(OH)2D3) on cutaneous inflammation, epidermal proliferation and keratinization in psoriasis: a placebo-controlled, double-blind study

The aim of the present study was to discover to what extent 1.24(OH)₂D₃ ointment (tacalcitol; 4 μg/g) can modulate epidermal proliferation and keratinization, and several aspects of inflamation. Ten patients with psoriasis vulgaris were included in a placebo-controlled, double-blind study, using 1,24(OH)₂D₃ ointment (4μg/g). Before, and after 8 weeks of treatment, punch biopsies were taken from lesions treated with the active agent and placebo-treated lesions. An immunohistochemical study was carried out using monoclonal antibodies against the hyperproliferation-associated keratin 16, against cycling nuclei, filaggrin, involucrin, T lymphocytes, Langerhans cells, CD14 and polymorphonuclear leucocytes (PMN). The Wilcoxon test for matched pairs was used for statistical analysis of results. The biopsies from the lesions treated with the active agent showed a statistically significant change towards normalization of all aspects of inflammation studied, and of epidermal proliferation and keratinization, but there did not appear to be any effect on Langerhans cells. The only parameter which showed a significant alteration in the placebo-treated lesions was the number of cycling nuclei in the epidermis (P≤0.02). However, the biopsies from the plaques treated with the active agent showed a greater decrease of cycling cells (decrease: M_active=70, M_placebo=53) and a lower P-value (≤0.01). We therefore conclude that at the cell biological level 1.24(OH)₂D₃ ointment (4μg/g) has a substantial effect on several cell types, with regard to inflammation, epidermal proliferation and keratinization, with the exception of Langerhans cells.     

A double-blind study of topical 1α,25-dihydroxyvitamin D3 in psoriasis

Several open studies with active forms of vitamin D3 have been reported to be effective in the treatment of psoriasis. We report a double-blind study of 1 alpha,25-dihydroxycholecalciferol in psoriasis using 0.5 microgram of active substance applied topically twice daily. In contrast to previous studies, the present investigation does not provide evidence of clinical efficacy for the drug at that dosage and with the vehicle that was used.     

1α-25-dihydroxyvitamin D3 increases intracellular free calcium in murine B16 melanoma

Vitamin D3 and its active metabolite I alpha-25-dihydroxyvitamin D3 (I alpha-25-(OH)2D3) have been reported to play a role in melanogenesis. Physiological concentrations of I alpha-25-(OH)2D3 were found to acutely elevate intracellular free calcium (using Fura 2) in B16 primary (Io) cells. Membrane phosphoinositide turnover was unaffected by I alpha-25-(OH)2D3. The rise in intracellular free calcium was entirely dependent on extracellular calcium and was not mimicked by vitamin D3. However, in neither B16-Io nor B16-F1 melanoma cells did vitamin D3 or I alpha-25-(OH)2D3 increase melanin production.     

Treatment of Angioblastoma with Recombinant Interferon-α2

Abstract: interferon-α₂ has been used successfully to treat anglomatous lesions such as Kaposi sarcoma and life-threatening hemangiomas, possibly by its antlangiogenetic activity. We report the successful use of this agent in a child with an angloblastoma of the right leg.     

Treatment of mycosis fungoides with etretinate and low-dose interferon α2a

Aims To evaluate the efficiency and tolerance of a treatment regime with etretinate and low-dose interferon-α_2a(IFN α_2a) in mycosis fungoides. Background Although there is no curative therapy for mycosis fungoides, remissions have been induced with etretinate and IFNα_2a, even in advanced stages, Recently, it has been shown that this combination is more effective in the induction and maintenance of the response than the separate administration of each drug. Methods Prospective study which includes nine patients with mycosis fungoides treated with 0.7 mg/kg/day of etretinate and 3 × 10⁶ IU/day of subcutaneous IFNα_2a during the first 3 months. Afterwards, the dosage of INFα_2a was modified in accordance with the response, without the daily dosis of INFα_2a surpassing 6 × 10⁶ [ U. Results: At the end of the study, a favourable response was obtained in four of six patients (66%), of whom one showed a complete and three partial remission. Two patients were non-evaluable and one discontinued therapy with partial remission of disease due to adverse effects attributable to etretinate. Side-effects were dose-dependent and reversible. Conclusions The combination of etretinate, 0.7 mg/kg/day, and IFNα_2a, 3 × 10⁶ subcutaneous IU/day, could be recommended to induce substained complete remission in later stages of cutaneous T-cell lymphoma.     

1α,25-dihydroxyvitamin D3 modulates Ia antigen expression induced by interferon-γ and prostaglandin E2 production in Pam 212 cells

Recent investigations suggest that 1α,25-dihydroxyvitamin D₃ [1α,25(OH)₂D₃] has an effect on the regulation of immune responses and that keratinocyte (KC) expression of major histocompatibility complex class II antigens may be involved in immune responses. We investigated the modulation by 1α,25(OH)₂D₃ of Ia antigen expression induced by interferon-γ (IFN-γ) and prostaglandin E₂ (PGE₂) production in Pam 212 cells. 1α,25(OH)₂D₃ at 10^?6, 10^?8 or 10^?10m significantly decreased the levels of IFN-γ-induced Ia antigen expression in Pam 212 cells. Pam 212 cells produced PGE₂ and 1α,25-(OH)₂D₃ enhanced Pam 212 cell PGE₂ production. However, indomethacin (1, 5 and 10 μg/ml) did not abrogate the inhibitory effect of 1α,25(OH)₂D₃ on IFN-γ induction of Ia antigen expression in Pam 212 cells, indicating that the products of the cyclo-oxygenase pathway do not mediate 1α,25(OH)₂D₃ inhibition of IFN-γ induction of Pam 212 cell Ia antigen expression. Our studies suggest that in Pam 212 cells the levels of Ia antigen expression induced by IFN-γ and PGE₂ production are negatively and positively regulated by 1α,25(OH)₂D₃, respectively, and that 1α,25(OH)₂D₃ may play a role in the regulation of immune responses.     

The influence of 8-methoxypsoralen plus UV-A (PUVA) on the excretion of the main urinary metabolite of prostaglandins F1α and F2α in patients with psoriasis

The 24-h urinary excretion of 52, 7α-dihydroxy-11-ketotetranorprosta-1,16-dioic acid (PGF-M) was measured in thirteen psoriatic patients for 2 days before and 2 days after a single dose of 8-MOP plus UV-A. Before treatment, the excretion of PGF-M was significantly higher in males than females (mean ± s.d.: 26.05 ±8-83 μg/24 h compared to 16.27±5.09 μg/24 h; .P < 0.005). The mean 24-h excretion of PGF-M was not altered significantly for up to 48 h after the single dose of 8-MOP plus UV-A. This is compatible with previous findings that prostaglandin synthesis in the skin is not increased by 8-MOP plus UV-A.     

α1-Antitrypsin deficiency-associated panniculitis: case report and review of treatment options

Alpha(1)-antitrypsin deficiency, a relatively frequent mutation in the population, is associated with the development of panlobular emphysema and liver cirrhosis. The deficiency is in rare cases associated with the development of panniculitis, and very differentiated clinical courses have been reported in the literature. We report a case of panniculitis in a patient with alpha(1)-antitrypsin deficiency and describe briefly the pathophysiology of the disease and current treatment possibilities.     

Fecal α1-Antitrypsin Concentration and Gastrointestinal Permeability to Oligosaccharides in Atopic Dermatitis

Severe allergic protein-losing enteropathy has been described in childhood atopic dermatitis (AD). Minor morphologic and functional abnormalities of the gastrointestinal mucosa, including altered permeability to oligosaccharides, are not uncommon in this condition, but the prevalence of occult enteric protein loss is unknown. We measured the random fecal alpha 1-antitrypsin (AAT) concentration, an indicator of enteric protein loss, in children with and without AD and found no significant difference between the groups. In half of the patients with AD, gastrointestinal permeability to oligosaccharides was also measured, and no relationship between this and fecal AAT was found.     

β2 Microglobulin expression in keratoacanthomas and squamous cell carcinoma

The cell surface expression of beta-2-microglobulin (beta 2 M) was investigated in 33 keratoacanthomas (KA) and 58 squamous cell carcinomas (SCC) to determine whether this antigen was expressed to a different extent in these two conditions and, thus, whether this constitutes a reliable and practical test for distinguishing them. Loss of beta 2 M expression was not a reliable feature for distinguishing between KA and SCC and seemed to be related more to the degree of cellular differentiation and maturation, than to malignancy as such.