The continued use of sunscreen prevents the development of actinic keratosis in aged Japanese subjects

Abstract

It is well known that the trigger for actinic keratosis (AK) mainly depends on UV exposure. We evaluated the effects of long-term use of sunscreen on the histopathological and dermoscopic changes of AK in aged patients. Eighteen months use of sunscreen produced no change in the number of actinic keratoses or the advancement of histological grade. Although a significant decrease was not observed in the number of positive cells of p53, Ki-67 and COX-2 of the subjects who used sunscreen for 18 months, the downward tendencies of these proteins were observed. The continued use of sunscreen decreased the number of CD31-positive vessels significantly using the Chalkley method, and a significant improvement in scaling and vessel dots was found by dermoscopic study. Moreover, a relationship was found in the amount of sunscreen use and the number of actinic keratoses. Considering these results, it was thought that application of sunscreen reduces the risk of advancement of AK to higher grade AK and squamous cell carcinoma. K E Y W O R D Sactinic keratosis, aged subjects, Japanese, prevention, sunscreen

The effects of continuous application of sunscreen on photoaged skin in Japanese elderly people—the relationship with the usage

“…47,48 However, in our previous study, no statistically significant difference was observed in the number of AK lesions before and after application of sunscreen, and the number of AK lesions decreased in only a small proportion of the subjects. 12 It is reported that more marked wrinkle formation and skin sagging are observed in Caucasian females compared to similar aged Japanese females. 8 When compared to Caucasians, Japanese are thought to have a lower sensitivity to UV and less susceptibility to photocarcinogenesis and photoaging because they have a lower incidence of AK and SCC, and characteristics of lower risk factors for AK such as lower skin phototypes or darker eye colors.…”

“…These results indicated the preventive effect of sunscreen against AK and SCC in Japanese people. 12 In Caucasians, many reports demonstrate the disappearance of AK after long-term application of sunscreen. 47,48 However, in our previous study, no statistically significant difference was observed in the number of AK lesions before and after application of sunscreen, and the number of AK lesions decreased in only a small proportion of the subjects.…”

“…These results indicate that continuous application of sunscreen is effective in suppressing AK progression and generation, and for the prevention of SCC development. 12 In the present study, we investigated the effects of continuous application of sunscreen for 18 months on photoaging in elderly people.…”

Imiquimod has strain-dependent effects in mice and does not uniquely model human psoriasis

“…This study used RNA-seq to investigate the psoriasiform phenotype that develops following topical Aldara (5% IMQ) treatment in male and female mice of seven laboratory mouse strains (C57BL/6 J (B6), BALB/cJ, CD1, DBA/1 J, FVB/NJ, 129X1/SvJ, and MOLF/EiJ) [19]. The IMQ psoriasiform phenotype has previously been evaluated using microarrays [2, 20–22], but to our knowledge has not yet been evaluated by RNA-seq.…”

The effects of continuous application of sunscreen on photoaged skin in Japanese elderly people – the relationship with the usage

“…These results indicate that continuous application of sunscreen is effective in suppressing AK progression and generation, and for the prevention of SCC development. 12 …”