Intense pulsed light (IPL) therapy is reported to be effective for pigment removal from pigmented lesions. However, the dynamic mechanism of pigment removal by IPL therapy is not completely understood. We investigated the mechanism of IPL therapy for the removal of pigmented skin lesions through non-invasive observation of the epidermis. Subjects with solar lentigines on the face were treated with three sessions of IPL therapy. The solar lentigines were observed on consecutive days after the treatments using reflectance-mode confocal microscopy (RCM) and optical coherence tomography (OCT). In addition, desquamated microcrusts that formed after the treatment were investigated by transmission electron microscopy (TEM). The images of RCM and OCT showed that the melanosomes in the epidermal basal layer rapidly migrated to the skin surface. The TEM images of the extruded microcrusts revealed numerous melanosomes together with cell debris. It was also found that the IPL irradiated melanocytes in the lesions seemed to be left intact and resumed their high activity after treatment. We conclude that IPL therapy effectively removed the dense melanosomes in the epidermal-basal layer. However, additional application of suppressive drugs such as hydroquinone or Q-switched laser irradiation is necessary to suppress the remaining active melanocytes.

These results indicate that the morphology and areas of sagging in male faces are similar to those in females in the cheek, but sagging at the lower eyelid is more severe in males after middle age. Furthermore, the dermal elasticity of male facial skin decreased with age similar to that of females, and may therefore be associated with the sagging formation in male faces.

Daily exposure to sunlight is known to affect the structure and function of the epidermal basement membrane (BM), as well as epidermal differentiation and epidermal barrier function. The aim of this study is to clarify whether the inhibition of BM‐degrading enzymes such as heparanase and matrix metalloproteinase 9 (MMP‐9) can improve the epidermal barrier function of facial skin, which is exposed to the sun on a daily basis. 1‐(2‐hydroxyethyl)‐2‐imidazolidinone (HEI) was synthesized as an inhibitor of both heparanase and MMP‐9. HEI inhibited not only the BM damage at the DEJ but also epidermal proliferation, differentiation, water contents and transepidermal water loss abnormalities resulting from ultraviolet B (UVB). This was determined in this study by the use of UVB‐induced human cultured skins as compared with the control without HEI. Moreover, topical application of HEI improved epidermal barrier function by increasing water content and decreasing transepidermal water loss in daily sun‐exposed facial skin as compared with non‐treated skins. These results suggest that the inhibition of both heparanase and MMP‐9 is an effective way to care for regularly sun‐exposed facial skin by protecting the BM from damage.

The aim of this study was to determine differences in the functional properties of the stratum corneum of children and adults, focusing on the influence of approaching puberty. Biophysical measurements were made of the stratum corneum of 32 healthy Japanese children aged 10-14 years and their mothers in summer and the following winter. The children showed significantly lower skin surface hydration. Stratum corneum barrier function, evaluated in terms of trans-epidermal water loss, was poorer on the forearm in the children than in the adults regardless of season. By contrast, the stratum corneum barrier of the cheek, which was better in the children, tended to become poorer when the children reached puberty. Although the immaturity of the cornified envelopes of the superficial corneocytes, which ratio increased significantly in winter, was not different from that of adults, the corneocytes were significantly smaller in the children, suggesting a more rapid turnover of the stratum corneum. The amount of skin surface lipid, which was measured only on the cheek, remained low until 13 years of age, but at 14 years of age it increased remarkably, approaching adult levels. We conclude that, until puberty, most functional characteristics of the skin of children remain distinct from those of adults.

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For understanding the clinical significance of sunscreen, representative photodermatoses including xeroderma pigmentosa, polymorphous light eruption, chronic actinic dermatitis and porphyria were explained. In addition, several topics concerning strategy of sunscreen use were reviewed. Finally, new strategies of sun-protection with metallothionein protein and NF-jB decoy were introduced.

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