1-alpha-24-dihydroxyvitamin-d3 and Inflammation

Vitamin D3 analogs interfere with various aspects of epidermal growth, inflammation, and cellular differentiation. Most data are derived from in vitro studies. In the present review, the in vivo effects of vitamin D3 analogues on the psoriatic plaque are discussed. Calcipotriol, tacalcitol, and calcitriol in ointment modulate aspects of epidermal growth, differentiation, and inflammation. Immunohistochemical studies suggest that the inflammatory changes might be more expressed after treatment with calcitriol and tacalcitol. Flow cytometric quantification of the percentage of cells in SG2M phase and of keratin 10-positive cells revealed that calcipotriol reduced both indices significantly during treatment of psoriatic plaques. Flow cytometric analysis of epidermal cell suspensions using triple labeling for epidermal proliferation, expression of keratin 10, and vimentin permits a quantitative assessment of DNA synthesis selectively in the basal cells of the epidermis, an estimation of the distribution of the basal and suprabasal compartments, and a quantification of the distribution of mesenchymal and nonmesenchymal cells. Using this approach, the interference of tacalcitol with growth control of basal cells was demonstrated. Remarkably, recompartmentalization of basal and suprabasal cells and mesenchymal and nonmesenchymal cells proved to be inconspicuous during this treatment.

Topics: Calcitriol; Dihydroxycholecalciferols; Epidermis; Flow Cytometry; Humans; Immunohistochemistry; Inflammation; Psoriasis

The clinical efficacy and tolerability of the vitamin D3 analogues calcitriol, calcipotriol and 1 alpha, 24 dihydroxyvitamin D3 in the treatment of psoriasis have been assessed in various clinical studies. In vitro and in vivo investigations have shown interference of these compounds with epidermal growth, keratinisation and inflammation. In this study we quantified the in vivo cell biological effects during treatment of psoriatic plaques with 1 alpha, 24 dihydroxyvitamin D3. By using a flow cytometric triple labelling procedure, we could discriminate different epidermal subpopulations, permitting precise assessment of epidermal cell cycle kinetics. Twenty patients with plaque-type psoriasis were treated in a double-blind placebo-controlled left-right comparative study with 1 alpha, 24 dihydroxyvitamin D3 ointment (4 micrograms/g applied once daily) for 8 weeks. Epidermal cell suspensions prepared from keratotome biopsies taken before and after treatment were stained with TO-PRO-3 iodide (a new DNA fluorochrome) and monoclonal antibodies against keratin 10 (as a marker for differentiation) and vimentin (as a marker for inflammation), simultaneously. The flow cytometric analyses showed a significant decrease of proliferating basal keratinocytes in verum-treated lesions, whereas such a decrease was not observed in placebo-treated lesions. The amount of keratin 10-positive keratinocytes increased and the presence of vimentin-positive cells decreased in cell suspensions derived from both verum- and placebo-treated lesions, but these effects were not significant. We conclude that multiparameter flow cytometry promises to be an adequate approach to assess the interference of antipsoriatic treatments with cutaneous inflammation, epidermal proliferation and keratinisation. Topical 1 alpha, 24 dihydroxyvitamin D3 seems to exert its in vivo antipsoriatic effect mainly through an inhibition of epidermal growth.

Topics: Administration, Cutaneous; Adult; Aged; Biopsy; Cell Cycle; Cell Differentiation; Cell Division; Cells, Cultured; Dermatologic Agents; Dihydroxycholecalciferols; DNA; Double-Blind Method; Epidermis; Female; Flow Cytometry; Fluorescent Dyes; Humans; Inflammation; Keratins; Male; Middle Aged; Placebos; Psoriasis; Vimentin

The aim of the present study was to discover to what extent 1,24(OH)2D3 ointment (tacalcitol; 4 micrograms/g) can modulate epidermal proliferation and keratinization, and several aspects of inflammation. Ten patients with psoriasis vulgaris were included in a placebo-controlled, double-blind study, using 1,24(OH)2D3 ointment (4 micrograms/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 < or = 0.02). However, the biopsies from the plaques treated with the active agent showed a greater decrease of cycling cells (decrease: Mactive = 70, Mplacebo = 53) and a lower P-value (< or = 0.01). We therefore conclude that at the cell biological level 1,24(OH)2D3 ointment (4 micrograms/g) has a substantial effect on several cell types, with regard to inflammation, epidermal proliferation and keratinization, with the exception of Langerhans cells.

Topics: Cell Division; Dihydroxycholecalciferols; Double-Blind Method; Epidermis; Filaggrin Proteins; Humans; Immunohistochemistry; Inflammation; Keratins; Psoriasis

Tacalcitol (1,24(R)(OH)2D3, TV-02) inhibited the TPA-induced inflammatory cell infiltration (largely neutrophils) histopathologically and myeloperoxidase (MPO) activity dose-dependently. Tacalcitol inhibited the mRNA expression and protein production of TPA-induced macrophage inflammatory protein-2 (MIP-2) and KC, the functional analogue of human interleukin (IL)-8, in the skin. Immunohistochemical staining of the TPA-applied skin revealed that mast cells expressed MIP-2, whereas KC was observed in keratinocytes, fibroblasts and outer root sheath of hair follicles. Furthermore, tacalcitol inhibited TPA-induced mast cell degranulation 24 hr after application without influence on the total number of mast cells. In this study, tacalcitol was found to have an inhibitory effect on cutaneous inflammation such as inhibition of neutrophil infiltration, MIP-2 and KC production, and mast cell degranulation in TPA-treated hairless mice. These results suggest that tacalcitol modulates cutaneous inflammation as well as keratinocyte proliferation and differentiation, and the inhibitory effect of tacalcitol on cutaneous inflammation may contribute to clinical the effectiveness in the treatment of psoriasis.

Topics: Administration, Cutaneous; Animals; Anti-Inflammatory Agents; Base Sequence; Dermatitis; Dihydroxycholecalciferols; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Female; Immunohistochemistry; Inflammation; Inflammation Mediators; Mast Cells; Mice; Mice, Hairless; Molecular Sequence Data; Neutrophil Infiltration; Peroxidase; Random Allocation; Reverse Transcriptase Polymerase Chain Reaction; Tetradecanoylphorbol Acetate