Popadic, S. (24830928800)S. (24830928800)PopadicRamic, Z. (6603943950)Z. (6603943950)RamicMedenica, L. (16744100000)L. (16744100000)MedenicaMostarica Stojkovic, M. (6701741422)M. (6701741422)Mostarica StojkovicTrajković, V. (7004516866)V. (7004516866)TrajkovićPopadic, D. (6602255798)D. (6602255798)Popadic2025-07-022025-07-022008https://doi.org/10.1159/000135639https://www.scopus.com/inward/record.uri?eid=2-s2.0-47249109336&doi=10.1159%2f000135639&partnerID=40&md5=4ea8b0c4c0548dbdabb574a780161146https://remedy.med.bg.ac.rs/handle/123456789/14338Background: Vitamin A and D analogues play an important role in epidermal homeostasis and are used in the treatment of various skin diseases. The failure of retinoid and vitamin D treatments is sometimes difficult to explain. Methods: We analyzed the effect of all-trans retinoic acid (all-trans RA), 13-cis retinoic acid (13-cis RA), ergocalciferol and cholecalciferol in keratinocyte cultures established from adult donors, on the cell proliferation by means of [3H]thymidine incorporation and apoptosis after fluorescein diacetate/trypan blue staining. Results: All tested agents exerted a dose-dependent inhibition of keratinocyte proliferation in the concentration range of 1.25-5 μM. Based on IC50 values, the antiproliferative efficiency was as follows: cholecalciferol > ergocalciferol = all-trans RA > 13-cis RA. The observed effect of cholecalciferol and ergocalciferol, but not retinoids, involved the induction of apoptotic cell death. Combining vitamins A and D did not further increase the proliferation block and even displayed an antagonistic effect. Conclusion: The susceptibility of keratinocytes to the antiproliferative action of vitamins A and D was markedly different in cell cultures derived from different donors, indicating a possible predictive value of the in vitro testing for the efficiency of the clinical response to these agents. Copyright © 2008 S. Karger AG.Adult keratinocytes, in vitroApoptosisCholecalciferolErgocalciferolProliferationRetinoids