Functional and structural age-related changes in the scalp skin of Caucasian women.

BACKGROUND: Ageing of the skin, being chronological or sun induced is highly documented. Scalp, as a specific skin site, has, however, received little attention. This work attempted to describe functional and structural alterations that occur in scalp skin with ageing. METHODS: Two different age groups (N = 15 each; 30 ± 3 and 62 ± 2 y.o. respectively) of Caucasian women participated in the study. Some functional parameters (TEWL, Sebum level, Hydration, T°) were recorded on the vertex part of the scalp, after having cut the hair flat on the scalp surface. Imaging of some structural criteria was carried out using high-frequency ultrasound technique and optical coherence tomography on the same scalp site and on the mid-forehead, as a close control skin site. RESULTS: As compared with the younger group, the scalp of older women significantly showed a decreased TEWL and a slightly lower T°. The thickness of total skin (epidermis + dermis) increased with age on both scalp and on forehead. The thickness of scalp epidermis decreased with age while not significantly altered on forehead. Pseudoattenuation of ultrasound images increased in the older age group. Other criteria, such as sebum level, stratum corneum hydration, stratum corneum thickness, were not found altered with age. CONCLUSION: With ageing, some few functional and structural changes are observed in the scalp of Caucasian women. Similarities or differences with those previously reported in other skin sites are discussed.

The effect of age on skin color and color heterogeneity in four ethnic groups.

BACKGROUND: Few comparative data are available on age-related changes in skin color among different ethnic groups. The aim of the study was to measure and analyze the skin color and color heterogeneity in four different ethnic groups living in the same local environment and to determine the effects of age on these skin color characteristics. METHODS: Female volunteers (385) from four ethnic populations (African-American, Caucasian, Chinese and Mexicans) living in the same city were enrolled after informed consent. Skin color was measured on two facial areas, forehead and cheek. The subjects were further divided into six age ranges: 19-30, 31-40, 41-50, 51-60, 61-70 and 71-87 years to determine any age-related effects on the skin color and color heterogeneity in both areas. RESULTS: According to the L(*)a(*)b(*) CIE system, clarity (fairness/lightness) was found to be lower in the African-American group whereas the hue was lower in Caucasians, which means more red skin. A clear, statistically significant darkening of the skin with age was observed in all ethnic groups, while evidence of yellowing of the skin was shown in the Chinese volunteers. Overall, the skin color of the face of African-Americans was more heterogeneous than in the other ethnic groups, but showed the least increase with age. CONCLUSION: Our study revealed interesting differences in skin color and color heterogeneity with respect to ethnicity and age-related alterations. Data obtained are very useful in improving our knowledge about the skin of people of different origins and helps in the development of specific cosmetic products that are well adapted to all these populations.

Skin from various ethnic origins and aging: an in vivo cross-sectional multimodality imaging study.

BACKGROUND: Ethnic differences in skin structural features have not been thoroughly investigated, and the few reported studies are contradictory. Thus, we have carried out a set of in vivo measurements on the skin of about 400 volunteers from various ethnic origins living in the same environment. METHODS: Female subjects were distributed into four ethnic groups: African Americans, Mexicans, Caucasians, and Chinese. Inter- and intra-ethnic skin structural differences, according to age and anatomic site, were investigated using three non-invasive skin-imaging methods: ultrasound (US) at 25 and 150 MHz, and optical coherence tomography (OCT). RESULTS: The thickness of the skin is higher on the cheek compared with the dorsal and ventral forearm, with no ethnic or age-related specificity. We confirm that the sub-epidermal non-echogenic band is a sensitive marker of skin aging, and reveal for the first time that it is less pronounced in African Americans. From OCT images, we bring out evidence that the thickness of the dermal-epidermal junction (DEJ) decreased with age, and was higher in African Americans than in Caucasians. Finally, by comparing US images at 150 MHz with OCT images, we show that papillary dermis thickness can be measured and appears to be quite constant irrespective of age or ethnic group. CONCLUSION: Our study confirms that skin imaging is very attractive to further our knowledge of the morphology of skin from various ethnic origins. Regarding age effects, quantitative parameters have shown that they would be delayed in African Americans compared with all other ethnic populations.

Comparative study of the hydration of the stratum corneum between four ethnic groups: influence of age.

BACKGROUND: Several recent overviews have reported that significant work remains to be performed to understand and quantify the ethnic differences in skin properties. In this way, we have carried out a set of in vivo biophysical experiments on the skin of American women from different ethnic populations living in the same environment. Inter- and intraethnic skin micro relief results were already published, skin hydration differences are now reported here. METHODS: The skin water content was evaluated taking advantage of the new skin capacitance imaging technique which allows to study stratum corneum hydration without suffering of the influence of the skin micro-relief and hair on the measurement. Three hundred and eleven American women from four ethnic groups were enrolled in this study. The investigation was performed during the summer season of 2004 on the major relatively distinct ethnic groups of Chicago, which is to say: African American, Chinese, Caucasian and Mexican. The hydration of the skin was investigated on the dorsal and ventral forearm sites as a function of ethnicity and age. RESULTS: Skin dryness is higher on sun exposed sites for lighter skin tones, such as in Chinese and Caucasian women, than on sites that are primarily out of the sun; while, no skin dryness differences are seen on either site for African American and Mexican women whose skin is darker. The skin dryness does not change as a function of ethnicity for the younger group for either the ventral and dorsal site of the forearm. With age, however, the dryness of the skin is higher for African American and Caucasian women than for the two other ethnic groups, with a higher percentage increase in Caucasian women. CONCLUSIONS: This study has revealed that the hydration of the skin is different according to ethnicity and that the age effects are influenced by ethnicity, suggesting anatomical or physiological property differences in ethnic skin. This study has also pointed out that the SkinChip seems to be a convenient and fast way to investigate both the micro relief as previously published and the dryness of the skin on a large number of subjects, and in this way will be very useful to improve our knowledge about skin of people from different ethnic groups and helping to develop specific products that are customized to all these populations.

Nonablative remodeling: a 14-month clinical ultrasound imaging and profilometric evaluation of a 1540 nm Er:Glass laser.

BACKGROUND: Nonablative remodeling has been recently proposed as a new antiaging treatment with no downtime. OBJECTIVE: To evaluate the efficacy and safety of nonablative skin remodeling with a 1540 nm Er:glass laser and contact cooling on perioral and periorbital rhytides at 14 months follow-up. METHODS: Forty-two female patients (mean age 47 years), Fitzpatrick skin types I-IV were treated five times at 6-week intervals and checked 6 months after the last treatment. Patients were evaluated using clinical data, patient satisfaction (scale 1-4), digital pictures, ultrasound imaging, and profilometry data from silicone imprints in order to quantify the degree of improvement. RESULTS: All subjects reported an improvement in the quality and visual aspect of their skin at 6 months (mean patient satisfaction 3.06/4) and at 14 months after enrollment (mean patient satisfaction 2.90/4). This was confirmed by a 43.41% reduction of anisotropy (P < 0.001) 6 weeks after the fourth treatment, reaching 44.85% reduction 6 months after the fifth treatment (P <.001). Ultrasound imaging demonstrated a 17% increase in dermal thickness (P <.001) at 6 months and 11% 6 months after the last treatment (P <.05). A lack of immediate or late adverse effects was noted at all stages of the procedure. CONCLUSION: This study demonstrated that irradiation with a 1540 nm Er:glass laser emitting in a pulsed mode and coupled with an efficient cooling system increased dermal thickness, reduced the anisotropy of the skin, and improved clinical aspects. The lack of adverse effects within the 14 months confirmed that this procedure was safe. Overall the stability of the results many months after the treatment was remarkable.

Spatial variation of acoustic parameters in human skin: an in vitro study between 22 and 45 MHz.

This study of spatial variance of acoustic parameters was performed on eight nonfrozen samples of female abdominal skin (women 46.5 +/- 12.2 years old), obtained during plastic surgery. Intra- and interindividual variations are discussed on the basis of estimations of three acoustic parameters (slope of attenuation- beta; integrated attenuation coefficient- IAC; integrated backscattering coefficient- IBC) and one texture parameter (based on two estimators of effective density of scatterers: alpha(2) and alpha(1/2)) as a function of surface area and depth of acquisition in the frequency range 22 to 45 MHz. Values of intraindividual variations varied from 7.1% for IAC to 23.2% for IBC, and significantly decreased at a ratio between 1.2 to 2.3 when the acquisition surface area was increased from 4 mm(2) to 1 cm(2). Interindividual variations were higher than intraindividual variations, and varied from 14.2% for alpha(1/2) to 51% for IBC. The mean values (+/- SD) for all specimens combined, estimated with a large number of independent radiofrequency (RF) lines (400) and for a surface area of exploration of 4 cm(2), were 1.06 +/- 0.17 dB cm(-1) MHz(-1) for beta, 135 +/- 37 dB cm(-1) for IAC, (3.7 +/- 1.9) x 10(-2) cm(-1) sr(-1) for IBC, 1.40 +/- 0.17 scatterers/resolution cell for alpha(2) and 1.32 +/- 0.27 scatterers/resolution cell for alpha(1/2). Finally, attenuation micro(f) and backscattering coefficient sigma(b)(f) were compared to published results for the same parameters measured in human skin.

Potential of a high-frequency correlation method to study skin blood flow.

BACKGROUND/AIMS: The vast number of existing dedicated techniques proves that skin blood flow estimation is an unsolved problem. Specificities of cutaneous vascularization (very low blood velocity, noisy environment, complexity of the vascularization architecture) result in the unsuitability of conventional ultrasonic Doppler techniques (long acquisition time, low spatial resolution). The object here was to present a high-frequency time-domain correlation METHOD: In particular, the difficulties of adaptating this type of measurement (data processing, hardware problem) are pointed out. METHODS: Radio-frequency (RF) backscattered signals, obtained with a modified version of a home-made 20 MHz skin imaging system, are studied. Time shifts between successive windowed sections of the RF signals are determined by the mean of the cross-correlation algorithm. A realignment procedure (to remove the artefacts caused by the movements of the patient and the manipulator) and a stationary echo cancelling procedure (to remove the signals coming from the cutaneous tissues and to permit the detection of very small vessels) are used. RESULTS: In vitro results show that velocity measurements as low as 0.1 mm/s are attainable with a 80 &mgr;m axial resolution, and blood vessels of 100 &mgr;m are detectable. Our technique has also been validated by means of in vivo experiment on an erysipelas located on a human leg. In this way, a 180-&mgr;m-diameter blood vessel has been detected on a M-mode RF image and the corresponding velocity profile has been obtained. CONCLUSION: Further improvements can be expected, and the level of performance obtained in vitro in this work should be also attainable in vivo and should then provide an effective tool for skin physiology and pathology.