Laurence Ambroisine

Functional MC1R-Gene Variants Are Associated with Increased Risk for Severe Photoaging of Facial Skin

The objective of this study was to assess the association between melanocortin-1 receptor (MC1R) variants and the severity of facial skin photoaging. The study population comprised 530 middle-aged French women. A trained dermatologist graded the severity of facial skin photoaging from photographs using a global scale. Logistic regressions were performed to assess the influence of MC1R polymorphisms on severe photoaging with adjustment for possible confounders (demographic and phenotypic data and sun exposure intensity). Among the fifteen MC1R variants identified, the nine most common were V60L, V92M, R151C, R160W, R163Q, R142H, D294H, D84E, and I155T. One hundred and eighty-five individuals (35%) were WT homozygotes, 261 (49%) had one common variant, 78 (15%) had two common variants, and six (1%) had at least one rare variant. After adjustment for possible confounders, the presence of two common variants was already a risk factor for severe photoaging (AOR (95% confidence interval): 2.33 (1.17-4.63)). This risk reached 5.61 (1.43-21.96) when two major diminished-function variants were present. Surprisingly, the minor variant, V92M, was associated with increased risk of photoaging (2.57 (1.23-5.35)). Our results suggest that genetic variations of MC1R are important determinants for severe photoaging.

Self-reported skin sensitivity in a general adult population in France: data of the SU.VI.MAX cohort

Objective  This study aimed to examine the frequency of self‐assessed facial skin sensitivity and its different patterns, and the relationship with gender and sun sensitivity in a general adult population.

Effect of hormonal replacement therapy on skin biophysical properties of menopausal women

Background/purpose: Hormonal replacement therapy (HRT) has been shown in the past to influence well being as well as several somatic features in menopausal women. The aim of this analysis was to study the effect of HRT on various biophysical properties of the skin of menopausal women. Two sub‐samples were built to test the effect (1) of ‘short‐term’ HRT in recently menopausal women (n=15), and (2) the effect of ‘medium‐ and long‐term’ HRT in menopausal women (n=78).

MC1R gene polymorphism affects skin color and phenotypic features related to sun sensitivity in a population of French adult women.

The melanocortin‐1 receptor (MC1R) gene is known to play a major role in skin and hair pigmentation and to be highly polymorphic in Caucasians. This study was performed to investigate the relationships between MC1R gene polymorphisms and skin color in a large sample of French middle‐aged Caucasian women. The codons 60 to 265 and the codon 294 of the MC1R gene were sequenced in 488 women. The skin color was measured on the inner side of the forearm using a spectrophotometric instrument. Fifteen variants were identified: Arg151Cys, Arg160Trp, Arg142His, Asp294His, Ile155Thr, Asp84Glu, Val60Leu, Val92Met, Arg163Gln, Ser83Pro, Thr95Met, Pro256Ser, Val265Ile, Ala166Ala and Gln233Gln. Women carrying Arg151Cys, Asp294His, Arg160Trp and Asp84Glu variants had a significantly higher reflectance in the red region, which indicates a lower level of functional melanin. This association was the most pronounced for women carrying Asp84Glu. In contrast, no significant difference was observed for other variants. Moreover, associations between MC1R polymorphisms and the risks of experiencing sunburn and of having freckles were found independently of skin color. Our findings support the hypothesis that MC1R polymorphisms do not necessarily alter the skin color but should sensitize the skin to UV‐induced DNA damage.

Influence of skin colour on the detection of cutaneous erythema and tanning phenomena using reflectance spectrophotometry.

Background/purpose: This research aims at assessing the influence of baseline skin colour on the ability of reflectance spectrophotometry to detect cutaneous erythema induced by a low concentration of methyl nicotinate (2.5 mM) (first objective), and to detect tanning induced by ultraviolet rays (UVA+UVB) at infra‐erythemal doses (second objective).

Relationships between visual and tactile features and biophysical parameters in human facial skin

Background/purpose: Skin properties, such as colour, hydration and texture, can be studied on a qualitative basis by a clinical assessment or on a quantitative basis using techniques that measure biophysical properties of the skin. The aim of this study was to explore the links between facial skin features and a range of skin biophysical parameters using multivariate methods.

Sun-reactive Skin Type in 4912 French Adults Participating in the SU.VI.MAX Study¶

Phototype classifications were initially developed in an attempt to predict the skin reactions of patients to phototherapy and are now widely used to advise individuals with regard to sun protection. A transversal study was conducted on the SU.VI.MAX cohort to estimate the frequency of sunreactive skin features in a large, general adult population‐based sample, and to describe the associations between these features. The data were collected 3 years after the beginning of the SU.VI.MAX nutritional intervention study on 4912 volunteers (2868 women aged 35–60 years and 2044 men aged 45–60 years). A multiple correspondence analysis was performed to study the associations between the features. The results showed that these features correspond to a one‐dimensional phenomenon, which allowed us to establish a score to summarize skin sensitivity to sun exposure. Furthermore, we found a link between gender and phototype using the Césarini classification (phototype IV: 37% of women, 47% of men). The analysis of the relationship with sun‐reactive skin features and the score revealed the same trend. Phenotypic evaluation appears to be a good estimator of skin sensitivity to sun exposure for clinical screening or for use in research, and is easy to collect at a lower cost. Moreover, the sun sensitivity difference between gender should be considered in education about photoprotection.

Reference ranges of skin micro-relief according to age in French Caucasian and Japanese women

Background/purpose: The variation of skin surface morphological indicators according to age has not been frequently studied. The aim of this work was to establish French Caucasian and Japanese reference ranges of these indicators according to age.