2-methylene-19-nor-(20s)-1alpha-25-dihydroxyvitamin-d3 and Disease-Models--Animal

In this study, we aimed to ascertain the efficacy and determine the dose effects of a new analog of vitamin D, 2α-methyl-19-nor-(20S)-1α,25-dihydroxyvitamin D3 (2AMD), in decreasing fibrosis and improving renal function in a rat model of kidney disease.. Using the cyclosporine model of chronic kidney disease, we tested 4 dose regimens (2.5, 5, 10, and 20 ng/kg) of 2AMD by subcutaneous administration. The 2AMD analog was compared with another analog, 2-methylene-19-nor-(20S)-1α,25-dihydroxyvitamin D3 (2MD), given at 5 ng/kg.. After 28 days of cyclosporine administration with 5 ng/kg 2AMD or 2MD, blood urea nitrogen levels were decreased by 20% and 30%, with no increase in serum calcium. This dose significantly decreased collagen levels by 50%, as determined by relative measurements of birefringence elicited under polarized light following picrosirius red staining of kidney tissues. The 20 ng/kg dose of 2AMD was hypercalcemic, with consequent deleterious effects on measured parameters; however, all doses of 2AMD tested decreased collagen as determined by picrosirius staining. In Western blot analysis of extracts from rat kidneys treated with cyclosporine and 5 ng/kg 2AMD, the fibrotic markers, fibronectin and vimentin, were decreased compared with animals treated only with cyclosporine.. We found that both vitamin D analogs are potent inhibitors of kidney fibrosis with potential renoprotective activity.

Topics: Animals; Blood Urea Nitrogen; Calcitriol; Calcium; Collagen; Cyclosporine; Disease Models, Animal; Dose-Response Relationship, Drug; Fibronectins; Fibrosis; Immunosuppressive Agents; Kidney; Male; Rats, Sprague-Dawley; Renal Agents; Renal Insufficiency, Chronic; Vimentin

The active metabolite of vitamin D, 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)), and a series of 2-methylene-19-nor analogs of 1,25(OH)(2)D(3) were evaluated for their ability to reduce the size of utricles (comedolytic activity) in a rhino mouse model of acne. All analogs tested, as well as the native hormone, increased the skin epidermal thickness. In contrast, only a subset of analogs that lacked a full side chain and 25-hydroxyl group were found to possess comedolytic activity. A reduction in comedone area could be achieved without adversely affecting serum calcium levels. Although all compounds that contained a side chain ranging from 2 to 5 carbons in length had similar potency as comedolytic agents, increasing the length of the side chain resulted in a progressive increase in calcemic liability. Dose-response studies of the comedolytic analogs showed that an increase in epidermal thickness was achieved at a lower dose than that needed to induce comedolysis. Thus, we have identified a unique subset of vitamin D analogs that produce comedolysis in the absence of hypercalcemia. Further, the activity of vitamin D analogs in causing epidermal hyperproliferation has been distinguished from that resulting in a reduction in utricle size.

Topics: Acne Vulgaris; Animals; Calcitriol; Calcium; Cell Differentiation; Dihydroxycholecalciferols; Disease Models, Animal; Dose-Response Relationship, Drug; Epidermis; Ergocalciferols; Female; Hyperkeratosis, Epidermolytic; Isomerism; Male; Mice; Mice, Hairless; Mice, Mutant Strains