Understanding the causes of skincare product pilling.

BACKGROUND: Skincare and makeup "pilling" is an unsightly and undesirable phenomenon whereby skincare such as moisturizers or foundation ball up to form flakes on the skin. To date, the causes of skincare product pilling have not been studied. This study aimed to examine the relationship between skin physiology and pilling potential of sunscreen and foundation (the two products most reported by consumers to cause pilling). This study also examined the effects of product application methods on pilling. MATERIALS AND METHODS: 528 female volunteers from Guangzhou, China, aged between 20 and 49 years, underwent various clinical skin assessments, followed by three steps of product layering. Pilling was assessed after each product application step. RESULTS: 217 volunteers (41%) experienced pilling. The majority of pilling (n = 655 events) occurred following sunscreen application, while only a few pilling events (n = 35) occurred with foundation. Foundation improved pilling caused by sunscreen in 98.9% of cases. Volunteers experiencing pilling with both sunscreen and foundation had significantly lower facial skin hydration and oiliness, higher pH, and smoother skin texture (P < 0.05). Two application methods, rubbing of products in circular and linear motions, yielded the highest numbers of pilling events. CONCLUSION: This study has provided the first insights into the causes of pilling. Sunscreen is a promoter of pilling, while foundation may resolve sunscreen-induced pilling in many cases. Skin physiology, particularly drier, smoother skin with higher pH, and product application methods are likely contributing factors to this undesirable phenomenon.

Yellowness in skin complexion: Analysis of self-perception of women in China evaluated against clinical parameters of yellowness.

BACKGROUND: Skin "yellowness" is an abstract and subjective term, without a definitive measurement protocol. Objectives were to analyze Chinese women's self-perception of skin yellowness and associated parameters and identify objective clinical measurements that correlate with these perceptions. METHODS: Following focus group discussions, criteria for skin yellowness were defined, and validated by volunteer rankings of facial images. A typology study of 185 women was performed. Participants were grouped into yellow (Color Uniformity, Brightness and Transparency (CUBT) yellow scale grade > 3, chromameter b* value > 16) and non-yellow (CUBT yellow scale grade < 2, b* value < 14) groups. Participants self-evaluated their skin on yellowness, transparency, skin uniformity, dullness, radiance, oiliness, and texture. Expert assessments were performed to grade sebaceous pores, ocular area pigmentation, pigmentary spots and CUBT scores. Instrumental analysis of the skin was employed using corneometer, sebumeter, mexameter chromameter, and AGE reader. RESULTS: Women in the yellow group self-evaluated their skin as significantly duller, less uniform, and less radiant than women in the non-yellow group (P ≤ 0.05). Higher levels of ocular area pigmentation and lower facial skin uniformity and brightness (P < 0.001) were observed in women with yellow skin. CUBT expert grading showed lower pink skin color, but significantly higher beige, yellow, and olive pigmentation (P ≤ 0.05) in women in the yellow skin group. Melanin and b* values were significantly higher in women with yellow skin while L value was significantly lower. CONCLUSION: Self-perceived skin yellowness in Chinese women correlates to chromameter and mexameter measurements, as well as expert evaluation of ocular pigmentation and CUBT parameters.

Modeling of global skin aging indices among Caucasian and Asian women.

BACKGROUND: The skin aging process is defined as the gradual degradation of several skin properties such as firmness, color, or the appearance of wrinkles. These properties can be assessed by trained experts, who perform an overall evaluation of the entire face. OBJECTIVE: The objective of this paper is the construction of two Global Skin Aging Indices specifically designed to model the overall skin aging process of Caucasian and Asian women. METHODS: Two hundred forty Asian women and 129 Caucasian women aged between 20 and 60 years old are recruited. Parameters related to wrinkles, sagging, elasticity, and skin tone are measured (clinically or instrumentally). The global skin aging index is defined as the normalized projection on the first principal component of a principal component analysis of the skin measurements. Then, linear regressions are performed between the indices and age of both panels. RESULTS: The first principal component carries around 50% of the initial variance for both indices. Both Global Skin Aging Indices statistically correlate with age (R2 ≥ 0.7, p-value < 0.05). An equation linking the indices with age is computed. CONCLUSION: The proposed indices are good indicators of the overall aging process for Caucasian and Asian women. They offer new approaches to assess antiaging product efficacy.

Self-perceived and objective measurements of facial puffiness in Chinese women.

BACKGROUND: Facial puffiness, caused by mild or normal fluid retention, commonly experienced by women, may not pose a health risk, but it can be a cause of cosmetic concern. The objectives of this study were to determine whether self-perceived facial puffiness can be measured objectively. MATERIALS AND METHODS: A total of 151 Chinese women between 20 and 68 years of age were recruited. Facial water content, skin thickness, and elasticity were measured at two time points within a day (visit one occurred when the participants perceived they had facial puffiness; visit two occurred when the participants perceived their facial puffiness had subsided). Participants were also given a rating scale to self-evaluate their puffiness and firmness at different regions of the face. RESULTS: The participants could perceive a difference in facial puffiness between the two visits. Water content and skin thickness were significantly higher in all regions of the face for all participants during the first visit. Skin elasticity was also significantly different between visits one and two. There was a significant increase in water content and skin thickness in the lower eyelid region in women who were older than 40 years. CONCLUSION: This is the first study to show that self-perceived facial puffiness can be measured objectively and that skin elasticity can change significantly when facial puffiness subsides.

The effect of air pollution on the skin colour and tone of Chinese women: A multicentre cohort study.

BACKGROUND: Overall facial skin colour is an important sign of perceived health and attractiveness, is predetermined by genetic factors, and is influenced by cultural and living habits, ultraviolet (UV) exposure, climate/seasons and ageing. The objective of this study was to determine the impact of pollution on the skin colour of Chinese women. MATERIALS AND METHODS: A total of 203 Chinese women between 20 and 59 years of age participated in the study and were selected from two cities with different levels of air pollution. Skin colour (L*, a* and b* values), melanin and haemoglobin levels were measured at three sites: the cheek, eye and inner upper arm. Measurements of the inner upper arm were taken as this area of skin was exposed to air pollutants but had minimal exposure to UV light. RESULTS: There were significant differences in skin chromophores between Chinese women living in two different cities with different levels of pollution. The b* value (yellowness) was higher in the eye and cheek region, and the a* value (redness) was lower in the cheek and arm region for women in the moderately polluted city. The melanin index was significantly higher, and the haemoglobin level was lower for the eye region for women living in the city with a higher level of air pollution. CONCLUSION: This study has shown that air pollution may negatively affect the skin colour of Chinese women.

Activation of EGF receptor endocytosis and ERK1/2 signaling by BPGAP1 requires direct interaction with EEN/endophilin II and a functional RhoGAP domain.

Rho GTPases are important regulators for cell dynamics. They are activated by guanine nucleotide exchange factors and inactivated by GTPase-activating proteins (GAPs). We recently identified a novel RhoGAP, BPGAP1, that uses the BNIP-2 and Cdc42GAP homology (BCH) domain, RhoGAP domain and proline-rich region to regulate cell morphology and migration. To further explore its roles in intracellular signaling, we employed protein precipitations and matrix-assisted laser desorption/ionization mass-spectrometry and identified EEN/endophilin II as a novel partner of BPGAP1. EEN is a member of the endocytic endophilin family but its function in regulating endocytosis remains unclear. Pull-down and co-immunoprecipitation studies with deletion mutants confirmed that EEN interacted directly with BPGAP1 via its Src homology 3 (SH3) domain binding to the proline-rich region 182-PPPRPPLP-189 of BPGAP1, with prolines 184 and 186 being indispensable for this interaction. Overexpression of EEN or BPGAP1 alone induced EGF-stimulated receptor endocytosis and ERK1/2 phosphorylation. These processes were further enhanced when EEN was present together with the wildtype but not with the non-interactive proline mutant of BPGAP1. However, EEN lacking the SH3 domain served as a dominant negative mutant that completely inhibited these effects. Furthermore, BPGAP1 with a catalytically inactive GAP domain also blocked the effect of EEN and/or BPGAP1 in EGF receptor endocytosis and concomitantly reduced their level of augmentation for ERK1/2 phosphorylation. Our findings reveal a concomitant activation of endocytosis and ERK signaling by BPGAP1 via the coupling of its proline-rich region, which targets EEN and its functional GAP domain. BPGAP1 could therefore provide an important link between cytoskeletal network, endocytic trafficking and Ras/MAPK signaling.

Cortactin phosphorylation as a switch for actin cytoskeletal network and cell dynamics control.

Cortactin is an important molecular scaffold for actin assembly and organization. Novel mechanistic functions of cortactin have emerged with more interacting partners identified, revealing its multifaceted roles in regulating actin cytoskeletal networks that are necessary for endocytosis, cell migration and invasion, adhesion, synaptic organization and cell morphogenesis. These processes are mediated by its multi-domains binding to F-actin and Arp2/3 complex and various SH3 targets. Furthermore, its role in actin remodeling is subjected to regulation by tyrosine and serine/threonine kinases. Elucidating the mechanisms underlying cortactin phosphorylation and its functional consequences would provide new insights to various aspects of cell dynamics control.

BPGAP1 interacts with cortactin and facilitates its translocation to cell periphery for enhanced cell migration.

Rho GTPases control cell dynamics during growth and development. They are activated by guanine nucleotide exchange factors and inactivated by GTPase-activating proteins (GAPs). Many GAPs exist with various protein modules, the functions of which largely remain unknown. We recently cloned and identified BPGAP1 as a novel RhoGAP that coordinately regulates pseudopodia and cell migration via the interplay of its BNIP-2 and Cdc42GAP homology, RhoGAP, and the proline-rich domains. To further elucidate the molecular mechanism underlying cell dynamics control by BPGAP1, we used protein precipitations and matrix-assisted laser desorption/ionization mass spectrometry and identified cortactin, a cortical actin binding protein as a novel partner of BPGAP1 both in vitro and in vivo. Progressive deletion studies confirmed that cortactin interacted directly and constitutively with the proline-rich motif 182-PPPRPPLP-189 of BPGAP1 via its Src homology 3 domain. Together, they colocalized to periphery and enhanced cell migration. Furthermore, substitution of prolines at 184 and 186 with alanines abolished their interaction. Consequently, this BPGAP1 mutant failed to facilitate translocation of cortactin to the periphery, and no enhanced cell migration was observed. These results provide the first evidence that a RhoGAP functionally interacts with cortactin and represents a novel determinant in the regulation of cell dynamics.