Treatment of photoaged skin with topical tretinoin increases epidermal-dermal anchoring fibrils. A preliminary report
D. T. Woodley, A. S. Zelickson, R. A. Briggaman, T. A. Hamilton, J. S. Weiss, C. N. Ellis and J. J. Voorhees
Department of Dermatology, University of North Carolina, Chapel Hill.
Topical 0.1% tretinoin or vehicle control was applied daily to the forearm
skin of six caucasian adults for 4 months. Two-millimeter punch biopsy
specimens were obtained from treatment sites at the beginning and end of
the study period for electron microscopy. Anchoring fibrils within the
epidermal-dermal junction of skin treatment sites were quantitated by
blinded, standardized, computer-assisted morphometry. After 4 months of
continual daily treatment, skin sites that received topical tretinoin
showed double the anchoring fibril density compared with vehicle control
sites (1.34 anchoring fibrils per micron of lamina densa vs 0.65,
respectively). The possible mechanisms by which topical tretinoin increases
anchoring fibrils in skin include the drug's property of inhibiting
collagenase, a dermal enzyme that degrades anchoring fibril collagen. We
speculate that increased numbers of collagenous anchoring fibrils within
the papillary dermis of human skin is one of the connective-tissue
correlates of the clinical improvement observed in photoaged skin after
treatment with topical tretinoin.
