Chronological Aging in African-American Skin: A Reliable Photonumeric Scale Demonstrates Age and Body Mass Index as Contributing Factors.

BACKGROUND: Increased photoprotection by natural melanin allows for African-Americans to be less impacted by photoaging than Caucasians. However, less is known about chronological aging in this population. OBJECTIVE: To create a photonumeric scale for African-Americans to evaluate chronological skin aging and to explore contributing elements to intrinsic aging. METHODS: Standardized photographs of the upper inner arm were taken from 75 African-American participants. Five participants were chosen as standards to create a 9-point photonumeric scale (0 = none, 8 = most severe). The scale was utilized by three blinded dermatologists to independently rate participants' photographs. RESULTS: The interrater agreements were 0.768 (95% CI: 0.671-0.834) for trial 1 and 0.725 (0.608-0.794) for trial 2. The intrarater agreements were 0.757 (0.596-0.875), 0.850 (0.771-0.903), and 0.790 (0.686-0.855) for the three raters. Averaged chronological aging scores were correlated with participants' survey responses, which revealed age as a significant predictor (r = 0.72, p < 0.001). LIMITATION: Our study was limited by the sample size, although the number of study participants was similar on a investigation in Caucasians. CONCLUSION: This study created the first reliable photonumeric scale for chronologic skin aging in African-Americans and found increased age and greater BMI as contributors to intrinsic skin aging phenotype in this population.

Effect of Age, Gender, and Sun Exposure on Ethnic Skin Photoaging: Evidence Gathered Using a New Photonumeric Scale.

BACKGROUND: African-Americans are less affected by photoaging than lighter skin individuals. Although scales for photoaging have been developed for Caucasians and Asians, no scale exists for African-Americans. AIM: To develop a photonumeric scale for photoaging and to determine factors that contribute to photoaging in African-Americans. METHODS: Five participants' photographs were selected as standards to create a 9-point photonumeric scale (0 = none, 8 = most severe). Three blinded dermatologists used the scale to grade the remaining participants' photographs. RESULTS: Interrater reliabilities were 0.775 (95% CI: 0.635, 0.880) for trial 1 and 0.832 (0.747, 0.883) for trial 2. Intrarater reliabilities, assessed over a 1 week interval, were 0.863 (0.727, 0.940), 0.928 (0.890, 0.954), and 0.866 (0.739, 0.935) for the three graders, indicating strong agreement. Photoaging scores were then correlated with participants' survey on lifestyle factors, which yielded age as a significant predictor (r = 0.91, p < 0.001). Furthermore, multiple regression model to predict facial photoaging (adjusted R2 = 0.849) selected age (b1 = 0.111, p < 0.001), sun exposure (b2 = 0.206, p = 0.014), and gender (b2 = -0.388, p = 0.063) as the most important variables. CONCLUSIONS: A reliable photonumeric scale for photoaging in African Americans was developed. Age, sun exposure, and male gender were found to be contributory factors to photoaging.

Pigmentation in African American skin decreases with skin aging.

BACKGROUND: Tristimulus colorimetry, which uses the Commission Internationale de l'Eclairage L*a*b* model to quantify color, has previously been used to analyze pigmentation and erythema in human skin; however, colorimetry of African American skin is not well characterized. OBJECTIVE: We sought to analyze skin color patterns in African Americans and compare them with those of Caucasians. METHODS: Colorimetry readings of the sun-protected buttock and sun-exposed back of forearm were taken from 40 Caucasian and 43 African American participants from March 2011 through August 2015. African American participants also completed a lifestyle questionnaire. Correlation coefficients, paired t tests, and multivariable linear regression analyses were used for statistical comparisons. RESULTS: Forearm skin was lighter in African Americans ages 65 years and older versus 18 to 30 years (P = .02) but darker in Caucasians ages 65 years or older versus 18 to 30 years (P = .03). In African Americans ages 18 to 30 years, the buttock was darker than the forearm (P < .001), whereas in Caucasians the buttock was lighter than the forearm (P < .001). A lighter forearm than buttock was correlated with supplement use, smoking (ages 18-30 years), and less recreational sun exposure (ages ≥65 years) in African Americans. LIMITATIONS: Our study was limited by the sample size and focal geographic source. CONCLUSIONS: Pigmentation patterns regarding sun-protected and sun-exposed areas in African Americans may differ from that of Caucasians, suggesting that other factors may contribute to skin pigmentation in African Americans.

Suppression of mammary carcinoma cell growth by retinoic acid: the cell cycle control gene Btg2 is a direct target for retinoic acid receptor signaling.

The anticarcinogenic activities of retinoic acid (RA) are believed to be mediated by the nuclear RA receptor (RAR) and by the RA-binding protein cellular RA-binding protein-II (CRABP-II). In MCF-7 mammary carcinoma cells, growth inhibition by RA entails an early cell cycle arrest followed by induction of apoptosis. Here, we aimed to obtain insights into the initial cell cycle response. We show that a 3- to 5-h RA pulse is sufficient for inducing a robust growth arrest 2 to 4 days later, demonstrating inhibition of the G1-S transition by RA is triggered by immediate-early RAR targets and does not require the continuous presence of the hormone throughout the arrest program. Expression array analyses revealed that RA induces the expression of several genes involved in cell cycle regulation, including the p53-controlled antiproliferative gene B-cell translocation gene, member 2 (Btg2) and the BTG family member Tob1. We show that induction of Btg2 by RA does not require de novo protein synthesis and is augmented by overexpression of CRABP-II. Additionally, we identify a RA response element in the Btg2 promoter and show that the element binds retinoid X receptor/RAR heterodimers in vitro, is occupied by the heterodimers in cells, and can drive RA-induced activation of a reporter gene. Hence, Btg2 is a novel direct target for RA signaling. In concert with the reports that Btg2 inhibits cell cycle progression by down-regulating cyclin D1, induction of Btg2 by RA was accompanied by a marked decrease in cyclin D1 expression. The observations thus show that the antiproliferative activity of RA in MCF-7 cells is mediated, at least in part, by Btg2.