The relationship of skin color, UVB-induced erythema, and melanogenesis

The relationship between skin color, delayed erythema, and delayed tanning (DT) elicited by a single exposure of UVB was investigated. Both constitutive and facultative pigmentation were determined by skin reflectance using a melanometer. Skin reflectance using visible light was well correlated to the minimal immediate pigment darkening dose elicited by UVA irradiation, which may relate to epidermal melanin content, a determinant of skin color. Minimal erythemal dose (MED) was well correlated to skin color, but there was less correlation between minimal melanogenic dose and skin color or the MED, since melanogenesis is controlled by genetic factors. DT also correlated to the dose of UVB in terms of MED. A coefficient of the regression line of DT may suggest the tanning capacity of skin. The possibility of detecting mild photosensitivity in individuals from a regression line of the MED on skin color is suggested.     

Variants in melanogenesis‐related genes associate with skin cancer risk among Japanese populations

Human skin color is known to be associated with the risk of cutaneous cancer. Some reports indicated that pigmentation‐related gene variants were associated with cutaneous cancer risk in Caucasian populations, but there are no similar reports in East Asian populations. This study aimed to evaluate the association between pigmentation‐related genes and the risk of skin cancer in Japanese populations. We studied the associations between 12 variants of four pigmentation‐related genes and melanin index variations in 198 Japanese patients with skin cancer and compared these findings to those of 500 Japanese controls by using multiple logistic regression analysis. Furthermore, we analyzed an independent sample of 107 Japanese patients with skin cancer. A non‐synonymous variant, H615R in the oculocutaneous albinism 2 gene (OCA2), was associated with the risk of malignant melanoma in the Yamagata group (odds ratio [OR], 0.38; 95% confidence interval [CI], 0.17–0.86; P = 0.020). Another non‐synonymous variant, A481T in OCA2, was associated with the risk of squamous cell carcinoma and actinic keratosis in the Osaka group (OR, 3.16; 95% CI, 1.41–7.04; P = 0.005). In malignant melanoma cases, the minor allele in OCA2 H615R might have induced the development of lesions in sun‐exposed skin (OR, 26.32; 95% CI, 1.96–333; P = 0.014). Our results suggest that some OCA2 variants are definite risk factors for the onset of cutaneous cancer in Japanese populations.     

Visual attention to variation in female facial skin color distribution

Objectives  Visible skin condition of women is argued to influence human physical attraction. Recent research has shown that people are sensitive to variation in skin color distribution, and such variation affects visual perception of female facial attractiveness, healthiness, and age.
Methods  The eye gaze of 39 males and females, aged 13 to 45 years, was tracked while they viewed images of shape- and topography-standardized stimulus faces that varied only in terms of skin color distribution.
Results  The number of fixations and dwell time were significantly higher when viewing stimulus faces with the homogeneous skin color distribution of young people, compared with those of more elderly people. In accordance with recent research, facial stimuli with even skin tones were also judged to be younger and received higher attractiveness ratings. Finally, visual attention measures were negatively correlated with perceived age, but positively associated with attractiveness judgments.
Conclusions  Variation in visible skin color distribution (independent of facial form and skin surface topography) is able to selectively attract people's attention toward female faces, and this higher attention results in more positive statements about a woman's face.     

人皮肤黑素生成调控机制的研究进展

人皮肤黑素在黑素细胞的黑素小体内合成,受多重因素的复杂调控,包括转录调节、细胞内信号传导通路调节、产物的反馈调节,以及核受体、细胞因子等对黑素生成的正向（刺激）和负向（抑制）调节。在正常黑素生成过程中,小眼畸形相关转录因子是转录调控酪氨酸酶及其相关蛋白的最重要分子;环磷酸腺苷,蛋白激酶A通路、丝裂原激活的蛋白激酶通路、一氧化氮／环磷酸鸟苷,蛋白激酶G通路、二酯酰甘油／蛋白激酶c通路是参与黑素生成的最主要4条细胞内信号传导通路。对黑素生成有正向（刺激）作用的分子及其受体主要有G蛋白耦联受体及其配体、干细胞生长因子及其受体、核受体及其配体。对黑素生成有负向（抑制）作用的分子及其受体主要有Agouti信号蛋白及其受体、G蛋白耦联受体及其配体、细胞因子和生长因子及其受体。     

皮下埋植避孕剂对使用者体重的影响

目的:探讨皮下埋植避孕剂对使用者体重的影响以及可能的作用机制。方法:通过检索相关文献,了解皮下埋植避孕剂使用者的体重变化及其可能的作用机制。结果:(1)短期放置皮下埋植避孕剂(12个月以内)对使用者的体重影响不明显;(2)长期放置皮下埋植避孕剂(12月以后)对使用者的体重影响较为明显;(3)皮下埋植避孕剂导致体重变化的机制与瘦素有关,但是具体作用机制不详。结论:长期使用皮下埋植避孕剂对使用者体重有影响。     

Defining skin of color

In the past few years, increasing attention has been given to skin disease in individuals with skin of color (also termed ethnic skin, racial skin, black skin, or pigmented skin). We will attempt to identify those individuals with skin of color. We use this article as an introduction to a recurring series that will address cutaneous disease affecting these individuals.     

Dermal carbonyl modification is related to the yellowish color change of photo-aged Japanese facial skin

Background

The photo-aged facial skin is characterized by various unique features such as dark spots, wrinkles, and sagging. Elderly people, particularly Asians, tend to show a yellowish skin color change with photo-aging. However, there has been no analytical study conducted on this unique skin color change of the aged facial skin.

Objective

The purpose of the present study is to examine whether the carbonyl modification in the dermal protein is involved in the yellowish color change that occurs in the photo-aged skin.

Methods

Normal skin samples excised from the face, abdomen and buttock of variously aged Japanese were separated into the epidermal and the dermal portions. These skin samples were histologically examined for carbonyl modification. Moreover, an in vitro constructed dermis model composed of a contracted collagen gel was treated with acrolein or 4-hydroxynonenal. All these samples were also studied colorimetrically.

Results

The dermal samples obtained from the photo-aged facial skin exhibited an appearance of yellowish color, whereas neither the facial epidermis nor the dermis obtained from the abdomen or buttock showed such a yellowish discoloration. The upper layer of the dermis that revealed the yellowish color showed elastosis whose elastic fibers were found to colocalize with carbonyl protein as detected by a labeled hydrazide, as well as by an immunohistochemical examination using the antibody against acrolein adduct. Experimental induction of carbonyl modification in a dermis model in vitro by a long-term treatment with acrolein or 4-hydroxynonenal was found to show the appearance of the yellowish change which was also proven by an increase in b* value of colorimetry. It was more pronounced than that induced by glycation.

Conclusion

Our present results strongly suggest that carbonyl modification of the dermal protein is involved in the production of the yellowish color change that is noted in the photo-aged facial skin.     

Role of phototherapy in patients with skin of color

Phototherapy has proven to be one of the most versatile and effective treatment options for a variety of inflammatory and pigmentary skin diseases. However, the use of these treatment modalities in patients of color requires some special considerations. The modality chosen, the dosing of the treatment and duration of treatment are all issues to be considered for patients of color treated with ultraviolet phototherapy. In addition, there are some diseases which are more commonly seen in patients of color. These diseases may have better treatment outcomes using newer phototherapeutic options such as the long pulsed Nd:YAG laser or UVA1. As our population in the United States becomes more diverse it would behoove all dermatologists to acquaint themselves with the special circumstances of treating ethnic patients with phototherapy.     

Aging in skin of color

Ethnic skin is quickly emerging as the norm in the United States, and as the population becomes more diverse, there is also a projected rise in the number of aging adults. Given the paucity of data regarding aging in ethnic skin, the authors have consolidated available information for this population. Literature examining structural and functional variation of aging in ethnic skin types was primarily found through PubMed and supplemental textbook chapters. Aging is comprised of two synergistic processes, intrinsic or chronologic aging, and extrinsic aging. Caucasian, African American, East Asian, and Hispanic skin each have distinguishing features of aging, but all populations share dyspigmentation, rhytides, and skin laxity. Increased melanin content predisposes skin of color to a greater degree of hyperpigmentation, but skin thickness may protect against the formation of rhytides. Tailored prevention and treatment are also paramount in attaining favorable outcomes for this growing cohort.     

皮肤创伤修复过程中表皮生长因子与黑素细胞及黑素生成关系的研究进展

创伤修复是一个复杂的过程,包括炎症反应、细胞增殖、基质沉积以及组织重塑过程.多种细胞及细胞因子共同参与促进创伤愈合.表皮生长因子被认为是其中的关键因素.表皮生长因子在创伤愈合中的积极作用已在动物实验及临床应用上得以证实,而在创伤修复过程中,表皮生长因子与黑素细胞及黑素生成的关系并不明确.近年来,研究发现,表皮生长因子可以抑制激光术后黑素细胞表达黑素,从而改善炎症后色素沉着.     

Association of skin barrier genes within the PSORS4 locus is enriched in Singaporean Chinese with early-onset psoriasis

Psoriasis (OMIM#177900) is a common polygenic skin disorder affecting approximately 2% of the northern European population and 0.1% of the Han Chinese. Psoriasis patients suffer from chronic skin inflammation, manifested by erythematous scaly lesions. PSORS1-PSORS9 have been confirmed as psoriasis susceptibility loci in independent genetic studies on predominantly Caucasian populations, with psoriasis susceptibility loci (PSORS1, PSORS9) and additional loci at 9q33-34 and 2p22.3-11.2 reported in Han Chinese patients. In this study, we show the association of PSORS4 with psoriasis in Singaporean Chinese. Dense genotyping of single-nucleotide polymorphism-tagging candidate genes within the epidermal differentiation complex revealed significant association in the proximity of the involucrin gene (IVL); the strongest association was seen in early-onset psoriasis patients (P=0.0014). A follow-up genome-wide association screen localized the psoriasis susceptibility region to approximately 360 kb along chromosome 1 in the vicinity of IVL, small proline-rich region (SPRR) and proline-rich region 9 (PRR9) genes. The study of interactions between the causative variant(s) in this locus will provide insights into a possible role for epidermal barrier formation in the pathogenesis of psoriasis.