Effects of tretinoin on photodamaged skin. A histologic study.
The histologic effects of topical tretinoin therapy on photodamaged facial skin were investigated in two 24-week, double-blind, randomized, vehicle-controlled studies involving 533 subjects at eight US centers. Three concentrations of tretinoin (0.05%, 0.01%, and 0.001%) in a new emollient cream were studied. Pretherapy and posttherapy biopsy specimens from the periorbital (crow's foot) area were examined by conventional light microscopy and computerized image analysis. Four significant dose-dependent differences from vehicle were found in the tretinoin groups: increased epidermal thickness, increased granular layer thickness, decreased melanin content, and stratum corneum compaction. There was no significant difference between 0.001% tretinoin and the vehicle, and no obvious dermal changes were detected in any group. The four epidermal changes in tretinoin-treated skin establish the biologic activity of the new emollient cream formulation and may partially account for the clinical improvements in photodamage observed in the same group of subjects.
Bhawan
J
J
Department of Dermatology, Boston (Mass) University School of Medicine 02118.
Gonzalez-Serva
A
A
Nehal
K
K
Labadie
R
R
Lufrano
L
L
Thorne
E G
EG
Gilchrest
B A
BA
D000279:Administration, Cutaneous; D000328:Adult; D004311:Double-Blind Method; D004817:Epidermis / Q000187:drug effects / Q000473:pathology; D005145:Face; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D015603:Keratinocytes / Q000187:drug effects / Q000473:pathology; D008297:Male; D008543:Melanins / Q000032:analysis; D008544:Melanocytes / Q000187:drug effects / Q000473:pathology; D008875:Middle Aged; D009077:Mucins; D010919:Placebos; D012867:Skin / Q000737:chemistry / Q000187:drug effects / Q000473:pathology*; D015595:Skin Aging / Q000187:drug effects*; D014212:Tretinoin / Q000008:administration & dosage / Q000627:therapeutic use*
D008543:Melanins; D009077:Mucins; D010919:Placebos; D014212:Tretinoin