title: Topical retinaldehyde on human skin: biologic effects and tolerance.
abstract: The present study was designed to explore if *etinaldehyde, a natural metabolite of vitamin A, has any biologic activity and is tolerated by human skin. Biologic activity was shown by the induction of cellular retinoic acid-binding protein type 2 (CRABP 2) mRNA and protein; the rank order for CRABP-2 increase was retinoic acid > retinaldehyde > 9 cis retinoic acid > retinol > beta carotene. In volunteers treated 1-3 months with 0.5, 0.1, and 0.05% retinaldehyde, there was a dose-dependent and significant increase in epidermal thickness, keratin 14 immunoreactivity, and Ki67-positive cells. The area of distribution of involucrin, transglutaminase, and filaggrin immunoreactivity was also increased in a dose-dependent manner, and keratin 4 immunoreactivity was induced in the upper epidermis. In pilot clinical tolerance studies, 229 patients received topical retinaldehyde at different concentrations; the 1% preparation was tolerated by up to 70% of the treated subjects; tolerance of the 0.5% preparation was slightly better, whereas both 0.1 and 0.05% preparations applied on facial skin were well tolerated and allowed prolonged use (up to 3 years) in patients with inflammatory dermatoses. These findings indicate that topical retinaldehyde has biologic activity and is well tolerated on human skin.
authors.affiliation: Department of Dermatology, University Hospital, Geneva, Switzerland.
authors.forename: J H
authors.initials: JH
authors.lastname: Saurat
authors.forename: L
authors.initials: L
authors.lastname: Didierjean
authors.forename: E
authors.initials: E
authors.lastname: Masgrau
authors.forename: P A
authors.initials: PA
authors.lastname: Piletta
authors.forename: S
authors.initials: S
authors.lastname: Jaconi
authors.forename: D
authors.initials: D
authors.lastname: Chatellard-Gruaz
authors.forename: D
authors.initials: D
authors.lastname: Gumowski
authors.forename: I
authors.initials: I
authors.lastname: Masouyé
authors.forename: D
authors.initials: D
authors.lastname: Salomon
authors.forename: G
authors.initials: G
authors.lastname: Siegenthaler
mesh_terms: D000287:Administration, Topical; D015415:Biomarkers / Q000032:analysis; D004361:Drug Tolerance; D004817:Epidermis / Q000737:chemistry; D000091344:Filaggrin Proteins; D006801:Humans; D007107:Immune System / Q000737:chemistry; D007381:Intermediate Filament Proteins / Q000502:physiology; D010865:Pilot Projects; D011498:Protein Precursors / Q000502:physiology; D018168:Receptors, Retinoic Acid / Q000187:drug effects / Q000502:physiology; D012172:Retinaldehyde / Q000008:administration & dosage*; D012867:Skin / Q000187:drug effects*; D011503:Transglutaminases / Q000502:physiology; D015854:Up-Regulation / Q000502:physiology
chemical_list: D015415:Biomarkers; C000717249:FLG protein, human; D000091344:Filaggrin Proteins; D007381:Intermediate Filament Proteins; D011498:Protein Precursors; D018168:Receptors, Retinoic Acid; C082928:retinoic acid binding protein II, cellular; C032253:involucrin; D011503:Transglutaminases; D012172:Retinaldehyde