1-alpha-24-dihydroxyvitamin-d3 and Disease-Models--Animal

1,24-Dihydroxyvitamin D₃ (tacalcitol), a vitamin D(3) compound, has been used to treat T cell-mediated inflammatory skin diseases such as psoriasis, prurigo and vitiligo. The best-known mechanism of action of this compound is inhibition of the abnormal proliferation of keratinocytes and subsequent maturation; however, its effects on skin T-cell recruitment have not yet been evaluated. Cutaneous lymphocyte-associated antigen (CLA), a surface glycoprotein expressed on T cells, plays a critical role in skin T-cell infiltration. We recently reported that 1,25-dihydroxyvitamin D₃ inhibits skin infiltration of CD4+ T cells by suppressing CLA expression on T cells.. In this study, we investigated the effect of tacalcitol on CLA epitope decoration and on the levels of gut or lymph node homing receptor expression in human T cells.. We cultured human T cells with tacalcitol and analysed the effect on CLA expression and skin-homing ability, and evaluated glycosyltransferase mRNAs. We also performed an in vivo study using an antigen-dependent delayed-type hypersensitivity (DTH) mouse model and investigated the effect of tacalcitol on skin-infiltrating CD4+ T cells.. Tacalcitol downregulated the expression of CLA and, in parallel, the E- and P-selectin ligand function; however, it exerted no effect on other homing receptors. Subcutaneously and intraperitoneally administered tacalcitol downregulated skin infiltration of effector CD4+ T cells in an in vivo DTH mouse model.. These findings suggest that tacalcitol reduces skin inflammation by partially downregulating CLA expression levels.

Topics: Adult; Animals; Antigens, Differentiation, T-Lymphocyte; Cell Movement; Dermatitis, Contact; Dermatologic Agents; Dihydroxycholecalciferols; Disease Models, Animal; Down-Regulation; E-Selectin; Female; Flow Cytometry; Humans; Immunohistochemistry; Male; Membrane Glycoproteins; Mice; P-Selectin; Receptors, Lymphocyte Homing; Skin; T-Lymphocytes

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

This study focused on the effects of tacalcitol (1,24 (R) (OH)2D3, TV-02) ointment (20 micro g/g) on cutaneous inflammation, epidermal proliferation, and differentiation and compared them with tacalcitol ointment (2 micro g/g) and other anti-psoriatic ointments using hairless mice. Tacalcitol ointment (0, 2 and 20 micro g/g) significantly inhibited 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced cutaneous inflammation, histopathologically. The effect of tacalcitol ointment (20 micro g/g) on cutaneous inflammation was much stronger than that of tacalcitol ointment (0, 2 micro g/g), and as effective as calcipotriol ointment (50 micro g/g) or betamethasone valerate ointment (1.2 mg/g). Tacalcitol ointment (20 micro g/g) also significantly inhibited TPA-induced myeloperoxidase (MPO) activity, as effectively as calcipotriol ointment (50 micro g/g) or betamethasone valerate ointment (1.2 mg/g). The effect of tacalcitol ointment on epidermal proliferation [ornithine decarboxylase (ODC) activity] and differentiation [transglutaminase (TGase) activity] was dose-dependent from 0 micro g/g to 20 micro g/g. The effect of tacalcitol ointments on epidermal proliferation was significant at the doses of 2 micro g/g and 20 micro g/g, and that on epidermal differentiation was significant at the doses of 0.2 micro g/g or more. The effect of tacalcitol ointment (20 micro g/g) on epidermal differentiation was significantly stronger than tacalcitol ointment (2 micro g/g). In this study, tacalcitol ointment (20 micro g/g) was found to have a marked effect on cutaneous inflammation and improved effect on epidermal differentiation, although tacalcitol ointment (2 micro g/g) also had significant effects on epidermal proliferation and differentiation. These findings support the clinical effectiveness of tacalcitol ointment (20 micro g/g) against psoriasis.

Topics: Administration, Topical; Animals; Biopsy, Needle; Dermatitis; Dihydroxycholecalciferols; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Administration Schedule; Epidermis; Female; Immunohistochemistry; Mice; Mice, Hairless; Ointments; Psoriasis; Reference Values; Treatment Outcome

The irritant potential of calcipotriol, 1 alpha,24-dihydroxyvitamin D3 (tacalcitol) and 1 alpha,25-dihydroxy-vitamin D3 (calcitriol) was compared in a hairless guinea pig model, Randomized, occlusive patch testing for 2 days was used. Each group of 8 animals was tested simultaneously with the 3 substances and a placebo vehicle. 3 dose levels i.e. 500 micrograms/ml, 50 micrograms/ml and 5 micrograms/ml were used. Test sites were evaluated at day 2 (2 h after removal of the patches) and again at day 3. Evaluation was blinded and based on a multiple parameter assessment of skin irritancy, comparing clinical scoring, skin perfusion using high resolution laser Doppler image scanning, skin colour (a*, Minolta ChromaMeter) and skin thickening (20 MHz ultrasound) indicating oedema. Skin biopsies were taken for histological preparation and assessment of epidermal hyperplasia. No difference was observed between the irritant potential for calcipotriol, tacalcitol and calcitriol based on clinical scoring as well as objective non-invasive measuring techniques. All 3 substances showed a dose-dependent and equal increase in clinical irritation score, cutaneous blood flow, skin colour and epidermal hyperplasia. The cutaneous inflammatory reaction was dominated by vasodilation and increased cutaneous perfusion. Oedema formation was only seen at the highest dosages tested. Skin barrier damage was not induced as TEWL remained unaffected. The hairless guinea pig appears a valid model to test irritancy of topical D-vitamins since the same profile of irritancy was previously established in humans for 2 of the compounds tested, calcitriol and calcipotriol.

Topics: Administration, Topical; Analysis of Variance; Animals; Calcitriol; Dermatitis, Irritant; Dermatologic Agents; Dihydroxycholecalciferols; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Guinea Pigs; Laser-Doppler Flowmetry; Patch Tests; Random Allocation; Reference Values; Skin; Ultrasonography

Establishing guidelines and experimental models preclinical and clinical evaluations of new agents for treatment, and/or prevention of human diseases has become a task of crucial importance. Psoriasis is such one disease holding great interest for dermatology owing to its high rate of incidence and complexity of treatment. However the absence of psoriatic lesions in animals and the inability to induce them, calls for experimental techniques both in vitro and in vivo. The purpose of this study was to evaluate experimentally the effects of tacalcitol on cell proliferation and differentiation process. Thereafter a human pilot study on psoriatic patients has been developed.

Topics: Administration, Topical; Adult; Animals; Anti-Inflammatory Agents; Dihydroxycholecalciferols; Disease Models, Animal; Female; Humans; Male; Mice; Middle Aged; Parakeratosis; Pilot Projects; Psoriasis; Skin

Topics: Animals; Bone and Bones; Calcitriol; Dihydroxycholecalciferols; Disease Models, Animal; Female; Hydroxycholecalciferols; Minerals; Osteoporosis; Ovary; Rats; Rats, Inbred Strains