Tacrolimus ointment neither blocks ultraviolet B nor affects expression of thymine dimers and p53 in human skin.
BACKGROUND
There is a lack of data with regard to the interaction between ultraviolet (UV) radiation and topical calcineurin inhibitors.


OBJECTIVE
We aimed to investigate (1) the UV transmission through tacrolimus ointment and (2) the impact of topical exposure to tacrolimus on the protein expression of thymine dimers (TD) and p53 in human skin.


METHODS
Spectrophotometric measurements (290-400 nm) of tacrolimus ointment and the vehicle were performed. Eight subjects were treated with tacrolimus ointment and the vehicle thrice daily over a 3-day period on the back. Pre-treated sites and one control site were exposed to two minimal erythema doses UVB. Skin biopsies were taken 1h and 24h after irradiation. Immunohistochemical procedures were used for the detection of TD and p53.


RESULTS
Mean UV transmission was over 94% and did not significantly differ between tacrolimus ointment and the vehicle. Immunohistological examinations of TD and p53 expression did not demonstrate significant differences between irradiated sites, irradiated plus vehicle treated sites, and irradiated plus tacrolimus treated sites both 1h and 24h post-irradiation.


CONCLUSIONS
The present data suggest that tacrolimus ointment hardly has UV blocking capacities and does not significantly interfere with development and/or removal of local DNA damage in human skin.
Gambichler
Thilo
T
Department of Dermatology and Allergology, Ruhr-University Bochum, Gudrunstrasse 56, 44791 Bochum, Germany. t.gambichler@klinikum-bochum.de
Schlaffke
Axel
A
Tomi
Nordwig S
NS
Othlinghaus
Nick
N
Altmeyer
Peter
P
Kreuter
Alexander
A
D000279:Administration, Cutaneous; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019703:Calcineurin / Q000378:metabolism; D065095:Calcineurin Inhibitors; D004249:DNA Damage / Q000187:drug effects*; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009824:Ointments; D011740:Pyrimidine Dimers / Q000378:metabolism*; D012867:Skin / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology / Q000528:radiation effects; D013056:Spectrophotometry, Ultraviolet; D016559:Tacrolimus / Q000008:administration & dosage / Q000494:pharmacology*; D013997:Time Factors; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D014466:Ultraviolet Rays
D065095:Calcineurin Inhibitors; D009824:Ointments; D011740:Pyrimidine Dimers; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D019703:Calcineurin; D016559:Tacrolimus