Relation between skin micro-topography, roughness, and skin age

Effects of a leave-on product on the strength of the dermoepidermal junction: An exploratory, intraindividual, randomized controlled trial in older adults with dry skin

Background and Aims

Skin aging is associated with dry skin and a decrease of the strength of the dermoepidermal adhesion, which increases the risk for lacerations (skin tears). Application of leave-on products improves dry skin and seems to reduce skin tear incidence. The aim of this study was to measure the effects of a humectant containing leave-on product on the strength of the dermoepidermal junction in older adult participants with dry skin.

Methods

A randomized controlled trial using a split body design was conducted. One forearm was randomly selected and treated with a lipophilic leave-on product containing 5% urea for 8 weeks. The other forearm was the control. The parameters stratum corneum hydration (SCH), transepidermal water loss, pH, roughness, epidermal thickness and skin stiffness were measured at the baseline, Weeks 4 and 8. At Week 8, suction blisters were created and time to blistering was measured. Blister roofs and interstitial fluid were analyzed for Interleukin-1α, 6 and 8.

Results

Twelve participants were included. After 8 weeks treatment, SCH was higher (median difference 11.6 AU), and the overall dry skin score (median difference -1) and median roughness (Rz difference -12.2 µm) were lower compared to the control arms. The median group difference for Interleukin-1α was -452 fg/µg total protein (TP) in the blister roofs and -2.2 fg/µg TP in the blister fluids. The median time to blister formation was 7.7 min higher compared to the control arms.

Conclusion

The regular application of humectant containing leave-on products improves dry skin and seems to lower inflammation and contribute to the strengthening of the dermoepidermal adhesion. This partly explains how the use of topical leave-on products helps to prevent skin tears.

In Vivo Assessment of Skin Surface Pattern: Exploring Its Potential as an Indicator of Bone Biomechanical Properties

The mechanical properties of bone tissue are the result of a complex process involving collagen-crystal interactions. The mineral density of the bone tissue is correlated with bone strength, whereas the characteristics of collagen are often associated with the ductility and toughness of the bone. From a clinical perspective, bone mineral density alone does not satisfactorily explain skeletal fragility. However, reliable in vivo markers of collagen quality that can be easily used in clinical practice are not available. Hence, the objective of the present study is to examine the relationship between skin surface morphology and changes in the mechanical properties of the bone. An experimental study was conducted on healthy children (n = 11), children with osteogenesis imperfecta (n = 13), and women over 60 years of age (n = 22). For each patient, the skin characteristic length (SCL) of the forearm skin surface was measured. The SCL quantifies the geometric patterns formed by wrinkles on the skin's surface, both in terms of size and elongation. The greater the SCL, the more deficient was the organic collagen matrix. In addition, the bone volume fraction and mechanical properties of the explanted femoral head were determined for the elderly female group. The mean SCL values of the healthy children group were significantly lower than those of the elderly women and osteogenesis imperfecta groups. For the aged women group, no significant differences were indicated in the elastic mechanical parameters, whereas bone toughness and ductility decreased significantly as the SCL increased. In conclusion, in bone collagen pathology or bone aging, the SCL is significantly impaired. This in vivo skin surface parameter can be a non-invasive tool to improve the estimation of bone matrix quality and to identify subjects at high risk of bone fracture.

Impact of Indenter Size and Microrelief Anisotropy on the Tribological Behavior of Human Skin

Everyday, we interact with screens, sensors, and many other devices through contact with the skin. Experimental efforts have increased our knowledge of skin tribology but are challenged by the fact that skin has a complex structure, undergoes finite deformations, has nonlinear material response, and has properties that vary with anatomical location, age, sex, and environmental conditions. Computational models are powerful tools to dissect the individual contribution of these variables to the overall frictional response. Here, we present a three-dimensional high-fidelity multilayer skin computational model including a detailed surface topography or skin microrelief. Four variables are explored: local coefficient of friction (COF), indenter size, mechanical properties of the stratum corneum, and displacement direction. The results indicate that the global COF depends nonlinearly on the local COF, implying a role for skin deformation on the friction response. The global COF is also influenced by the ratio of the indenter size to the microrelief features, with larger indenters smoothing out the role of skin topography. Changes in stiffness of the uppermost layer of skin associated with humidity have a substantial effect on both the contact area and the reaction forces, but the overall changes in the COF are small. Finally, for the microrelief tested, the response can be considered isotropic. We anticipate that this model and results will enable the design of materials and devices for a desired interaction against skin.

Micro-relief characterization of benign and malignant skin lesions by polarization speckle analysis in vivo

BACKGROUND/PURPOSE

A recent direction in skin disease classification is to develop quantitative diagnostic techniques. Skin relief, colloquially known as roughness, is an important clinical feature. The aim of this study is to demonstrate a novel polarization speckle technique to quantitatively measure roughness on skin lesions in vivo. We then calculate the average roughness of different types of skin lesions to determine the extent to which polarization speckle roughness measurements can be used to identify skin cancer.

METHODS

The experimental conditions were set to target the fine relief structure on the order of ten microns within a small field of view of 3 mm. The device was tested in a clinical study on patients with malignant and benign skin lesions that resemble cancer. The cancer group includes 37 malignant melanomas (MM), 43 basal cell carcinomas (BCC), and 26 squamous cell carcinomas (SCC), all categories confirmed by gold standard biopsy. The benign group includes 109 seborrheic keratoses (SK), 79 nevi, and 11 actinic keratoses (AK). Normal skin roughness was obtained for the same patients (301 different body sites proximal to the lesion).

RESULTS

The average root mean squared (rms) roughness ± standard error of the mean for MM and nevus was equal to 19 ± 5 μm and 21 ± 3 μm, respectively. Normal skin has rms roughness of 31 ± 3 μm, other lesions have roughness of 35 ± 10 μm (AK), 35 ± 7 μm (SCC), 31 ± 4 μm (SK), and 30 ± 5 μm (BCC).

CONCLUSION

An independent-samples Kruskal-Wallis test indicates that MM and nevus can be separated from each of the tested types of lesions, except each other. These results quantify clinical knowledge of lesion roughness and could be useful for optical cancer detection.

Detection of skin wrinkles and quantification of roughness using a novel image processing technique from a dermatoscope device

OBJECTIVE

Cutaneous relief analysis is crucial in the development of new skincare products, as well as in the evaluation of dermatological treatments. The analysis can be performed by qualitative or quantitative methods. We propose a new algorithm to detect wrinkles and quantify skin roughness by image processing from a dermatoscope.

METHODS

A clinical study was carried out with 33 research participants, and images were collected with the dermatoscope and PRIMOS equipment for wrinkle evaluation at two different times: Day 0 (D0) and 45 days (D45) after the use of a dermocosmetic product. Later, a new algorithm was developed to detect wrinkles in the acquired images by applying filters and image transformations that generate a segmented image highlighting the wrinkles. A roughness calculation method is proposed from the pixels belonging to wrinkles.

RESULTS

Correlation between the values obtained by the PRIMOS equipment and the proposed system was verified. No correlation was found for data obtained at D0; however, there was correlation at time D45 by Spearman's similarity coefficient. By comparing roughness between times D0 and D45, the treatment was statistically significant for both PRIMOS and the proposed methodology data.

CONCLUSION

The wrinkle detection algorithm, in addition to the roughness calculation, demonstrated a sensitivity comparable to the PRIMOS system in evaluating the effectiveness of the dermocosmetic treatment.

SIGNIFICANCE

Considering the simplicity of the dermatoscope design compared to other established devices such as PRIMOS, the proposed system is promising as an alternative for dermatological evaluations.

Evaluation of a new connected portable camera for the analysis of skin microrelief and the assessment of the effect of skin moisturisers

BACKGROUND

Silicone replicas and non-contact methods are effective methods to analyse the micrometric scale of the skin microrelief. Yet, they imply data capture in research facilities. The capabilities of a new connected portable camera were evaluated to analyse microrelief under nomadic conditions, also studying the effect of moisturisers.

MATERIALS AND METHODS

3D depth maps were constructed using shape-from-shading algorithms. Roughness heterogeneity (Spa) was computed, and skin profiles were extracted to calculate roughness amplitude (Ra, Rq), as well as furrows/plateaus characteristics. Validation of the connected camera was performed on tanned cowhide leather and on the inner forearm skin of a single subject. The forearms of 18 subjects (23-60 years old) were also evaluated. While living their regular life, they self-performed triplicate acquisitions at various times. The effects of a placebo and of cream containing moisturisers-saccharide isomerate, urea or xylitylglucoside-anhydroxylitol-xylitol-were investigated, using untreated control skin as a reference.

RESULTS

Validation of the device on leather and forearm skin shows high repeatability. The 18 subjects show the known correlation between age and changes in microrelief. While testing formulas, 8 h after a single application, all decreased Spa (-1.6/-2.1 folds). Only saccharide isomerate and xylitylglucoside-anhydroxylitol-xylitol decreased Ra (-2.4/-2.8 folds). The sectional area of plateaus was reduced from -1.5 (urea) to -2.1 folds (xylitylglucoside-anhydroxylitol-xylitol). The height of plateaus is also decreased by all moisturisers, from -1.5 (urea) to -2.1 folds (xylitylglucoside-anhydroxylitol-xylitol).

CONCLUSION

This novel camera device enables microrelief analysis under nomadic conditions, allowing monitoring its changes along the day and upon moisturisers' application.

Evaluation and characterization of facial skin aging using optical coherence tomography

OBJECTIVES

The skin aging exposome encompasses internal and external factors that contribute to clinical signs of facial aging. Aging skin can be characterized by distinctive features such as wrinkles, lentigines, elastosis, and roughness. Optical coherence tomography (OCT) is capable of noninvasively measuring skin characteristics. This study aimed to assess bilateral features using OCT to explore temporal skin changes among decades and potential changes in facial skin aging based on laterality.

METHODS

A total of 97 subjects between 20 and 89 years old with Fitzpatrick skin types I to IV were enrolled. VivoSight, a Multi-Beam OCT system intended to gather topographical and histological images of skin, was used to scan the area inferolateral to the lateral canthus, bilaterally. Investigators compared characteristics of skin roughness, attenuation coefficient and blood flow across age groups and based on laterality to determine any differences.

RESULTS

Only data from successful OCT scans were used. Seventy subjects, 10 from each specified decade, had successful bilateral scans and were thus included in the analysis. Chronological aging was characterized by significantly decreased dermal attenuation coefficient with increased age. Skin roughness measurements showed trends of increased roughness with age; however, no statistically significant changes were seen between groups. Qualitative differences amongst scans taken on right and left sides of the face showed no significance regarding roughness, density or blood flow at depths ranging from 0.05 to 0.5 mm.

CONCLUSIONS

OCT is an effective method for evaluating changes in aging skin. Our results illustrate a decline in skin density with chronological age. Additionally, it was illustrated that structural change in the epidermis and dermis does occur, however on a microscopic scale, there are no significant differences based on laterality. OCT holds promise as a noninvasive technique for characterization of aging skin. Its utility and application in the clinical management and treatment of aged skin requires further research; however, the technology has potential to personalize therapies based on objective findings.

Quantification of Microstructural Changes in the Dermis of Elderly Women Using Morphometric Indices of the Skin Surface

OBJECTIVE

The main objective of this study was the development of a non-invasive mathematical marker of the skin surface, the characteristic length, to predict the microstructure of the dermis. This marker, at the individual level, is intended to provide the biological age of the patient in the context of personalised medicine for the elderly.

STUDY DESIGN

To validate this hypothesis, a clinical study was conducted on 22 women over 60 years old from a population of osteoporotic subjects who sustained a femoral neck fracture: a morphological analysis of the skin surface was performed on the patient's forearm and quantitatively compared with microarchitectural parameters of the dermis.

MAJOR RESULTS

The Elastin-to-Collagen ratio measured on dermis samples ranged between 0.007 and 0.084, with a mean of 0.035 ± 0.02. The surface characteristic length ranged between 0.90 and 2.621, with a mean of 0.64 ± 0.51. A very strong correlation was found between this characteristic length and the Elastin-to-Collagen ratio (r = 0.92).

CONCLUSIONS

This study proposes an original diagnostic tool based on morphometric indices of the skin surface and shows a direct quantitative relationship with the dermis microarchitecture and its collagen and elastin content. The proposed method allows reliable and easy access to the intrinsic ageing of the dermis, which would be a strong biomarker in a personalised collagen treatment approach.

Effect of collagen degradation on the mechanical behavior and wrinkling of skin

Chronological skin aging is a complex process that is controlled by numerous intrinsic and extrinsic factors. One major factor is the gradual degradation of the dermal collagen fiber network. As a step toward understanding the mechanistic importance of dermal tissue in the process of aging, this study employs analytical and multiscale computational models to elucidate the effect of collagen fiber bundle disintegration on the mechanical properties and topography of skin. Here, human skin is modeled as a soft composite with an anisotropic dermal layer. The anisotropy of the tissue is governed by collagen fiber bundles with varying densities, average fiber alignments, and normalized alignment distributions. In all finite element models examined, collagen fiber bundle degradation results in progressive decreases in dermal and full-thickness composite stiffness. This reduction is more profound when collagen bundles align with the compression axis. Aged skin models with low collagen fiber bundle densities under compression exhibit notably smaller critical wrinkling strains and larger critical wavelengths than younger skin models, in agreement with in vivo wrinkling behavior with age. The propensity for skin wrinkling can be directly attributable to the degradation of collagen fiber bundles, a relationship that has previously been assumed but unsubstantiated. While linear-elastic analytical models fail to capture the postbuckling behavior in skin, nonlinear finite element models can predict the complex bifurcations of the compressed skin with different densities of collagen bundles.

Lipid Nanoparticles Loaded with Selected Iridoid Glycosides as Effective Components of Hydrogel Formulations

One possibility of improving active ingredient penetration into deeper skin layers to enhance the cosmetic product effectiveness, is the application of lipid nanoparticles. The aim of the study presented in this paper was to evaluate the potential of hydrogel formulations enriched with iridoid glycosides-loaded lipid nanoparticles. Lipid nanocarriers were produced using an emulsification-ultrasonication method based on multiple emulsions. The encapsulation efficiency was determined at the level of 89% and 77% for aucubin and catalpol, respectively. The next stage was the incorporation of the obtained dispersions of lipid nanoparticles into hydrogel formulations, followed by determination of their physicochemical properties, shelf-life stability, and application properties (in vivo tests). The introduction of lipid nanoparticles increased the stabilization of the consistency of the obtained hydrogel formulations, and was confirmed by viscosity measurements. No effect of lipid nanoparticle incorporation on shelf-life stability of the hydrogels was detected. In vivo studies showed improvements in moisture content of the epidermis, transepidermal water loss, skin topography, and macrorelief parameters. In particular, a synergistic effect of the active ingredients and lipid nanoparticles on the anti-wrinkle effect, moisturizing effect, and regeneration of the protective barrier of the stratum corneum was evidenced. The attractiveness of aucubin and catalpol as cosmetic raw materials in hydrogel formulations was evidenced, especially when the iridoid glycosides were applied in the form of lipid nanoparticles.

Scientific validation of three-dimensional stereophotogrammetry compared to the IGAIS clinical scale for assessing wrinkles and scars after laser treatment

Measuring outcomes from treatments to the skin is either reliant upon patient’s subjective feedback or scale-based peer assessments. Three-Dimensional stereophotogrammetry intend to accurately quantify skin microtopography before and after treatments. The objective of this study is comparing the accuracy of stereophotogrammetry with a scale-based peer evaluation in assessing topographical changes to skin surface following laser treatment. A 3D stereophotogrammetry system photographed skin surface of 48 patients with facial wrinkles or scars before and three months after laser resurfacing, followed immediately by topical application of vitamin C. The software measured changes in skin roughness, wrinkle depth and scar volume. Images were presented to three observers, each independently scoring cutaneous improvement according to Investigator Global Aesthetic Improvement Scale (IGAIS). As for the results, a trend reflecting skin/scar improvement was reported by 3D SPM measurements and raters. The percentage of topographical change given by the raters matched 3D SPM findings. Agreement was highest when observers analysed 3D images. However, observers overestimated skin improvement in a nontreatment control whilst 3D SPM was precise in detecting absence of intervention. This study confirmed a direct correlation between the IGAIS clinical scale and 3D SPM and confirmed the efficacy and accuracy of the latter when assessing cutaneous microtopography alterations as a response to laser treatment.

Noninvasive evaluation of the influence of aucubin-containing cosmetic macroemulsion on selected skin parameters

BACKGROUND

Objective evaluation of skin condition on the basis of noninvasive methods has become obligatory and may be a good strategy for verifying the efficiency of new cosmetic active ingredients.

AIM

The aim of this study was to assess the influence of aucubin-containing cosmetic macroemulsion on skin parameters using the skin testing equipment.

PATIENTS/METHODS

The study was carried out on the group of 25 female volunteers of the mean age 27 ± 2 years. The skin parameters were measured using the following devices: Tewameter^® TM 300 (transepidermal water loss, TEWL), Corneometer^® CM 825 (skin hydration), Cutometer^® MPA 580 (skin elasticity), Visioscan^® VC 98 (skin topography), and Visioline^® VL 650 (skin macrorelief). All measurements were performed on the inner part of the left forearm.

RESULTS

The skin parameters measured revealed the beneficial influence of aucubin on TEWL and skin hydration level. The application of aucubin-enriched cream caused more significant improvements of all determined SELS parameters, in comparison with cream without it. An analogous tendency was noticed in the case of skin macrorelief parameters; the addiction of the active ingredient led to a decrease in the value of total wrinkle area and diminished the mean length and depth of single wrinkles.

CONCLUSIONS

Noninvasive methods of skin testing have provided a possibility of objective evaluation of the action of new active ingredients in cosmetic formulations. The study has proved the positive influence of aucubin on effectiveness of cosmetic macroemulsions, diminishing TEWL, increasing skin hydration level, and improving the values of SELS and skin macrorelief parameters.

Structural skin changes in elderly people investigated by reflectance confocal microscopy

BACKGROUND

Reflectance confocal microscopy (RCM) is particularly suitable for the study of skin ageing because it provides nearly histological information in vivo and non-invasively. However, there are no studies that evaluated RCM skin features of a large population older than 70 years.

OBJECTIVES

The aim of our investigation was to study age-related skin changes in an elderly population by RCM and to evaluate their topographical and gender differences.

METHODS

We obtained RCM images of photoprotected (volar arm) and chronic (face) and intermittently photoexposed (dorsal forearm) body sites of 209 volunteers (105 women and 104 men, mean age: 77.5, range 74-81 years). 15 previously reported and new RCM parameters related to skin ageing were assessed.

RESULTS

Photoexposed sites had thicker suprapapillary epidermis, more linear, distant and thin furrows, higher presence of mottled pigmentation, polycyclic papillae and coarse and huddled collagen and lower presence of dermal papillae than the photoprotected site. Irregular honeycomb pattern was not higher in photoexposed sites, indicating that it is probably more dependent on intrinsic ageing. Two ageing scores defined for facial skin ageing (epidermal disarray score and epidermal hyperplasia score) were found useful for the identification of photoageing. Gender differences only concerned some RCM parameters (i.e. thickness of different layers of the epidermis, furrows and collagen score) and some body sites, in line with the fact that women and men of our cohort had no major differences in clinically visible skin ageing.

CONCLUSIONS

Our study confirmed that RCM is a powerful non-invasive technique to microscopically quantify ageing signs and our observations contribute to highlight the differences between intrinsic and extrinsic ageing.

Epidemiology and Outcome Analysis of 470 Patients with Hand Burns: A Five-Year Retrospective Study in a Major Burn Center in Southwest China

Background

This retrospective study aimed to investigate the epidemiology of burns to the hand, including the causes, demographic data, management, and outcome in a single center in Southwest China between 2012 and 2017.

Material/Methods

A retrospective study included 470 patients with hand burns who were treated at a single hospital in Southwest China between 2012 and 2017. Demographic, injury-related, and clinical data were obtained from the clinical electronic data collection system.

Results

In 470 patients, men were more commonly admitted to hospital with hand burns (73.62%). Children under 10 years (29.57%) were the main patient group. Hospital admissions occurred in the coldest months, from December to March (55.11%). In 60.21% of cases, hand burns occurred outside the workplace. Fire (40.42%), electricity (30.85%), and hot liquids (20.21%) were the main causes of hand burns. Data from 428 patients showed that burns with a larger total body surface area and deeper burns were associated with surgery and amputation. Burn depth was a risk factor for skin grafting, and lack of burn cooling before hospital admission increased the risk of amputation. Data from 117 patients with localized burns showed that full-thickness burns and lack of cooling before admission were associated with an increased hospital stay.

Conclusions

The findings suggest that in Southwest China, prevention programs for children aged 0–9 years, injuries occurring in winter and non-workplace sites, and fire burns were imperative.

Skin Structure-Function Relationships and the Wound Healing Response to Intrinsic Aging

Significance: Chronic wounds, such as diabetic foot ulcers, venous stasis ulcers, and pressure ulcers affect millions of Americans each year, and disproportionately afflict our increasingly older population. Older individuals are predisposed to wound infection, repeated trauma, and the development of chronic wounds. However, a complete understanding of how the attributes of aging skin affect the wound healing process has remained elusive. Recent Advances: A variety of studies have demonstrated that the dermal matrix becomes thinner, increasingly crosslinked, and fragmented with advanced age. These structural changes, as well as an increase in cell senescence, result in altered collagen fiber remodeling and increased stiffness. Studies combining mechanical testing with advanced imaging techniques are providing new insights into the relationships between these age-related changes. Emerging research into the mechanobiology of aging and the wound healing process indicate that the altered mechanical environment of aged skin may have a significant effect on age-related delays in healing. Critical Issues: The interpretation and synthesis of clinical studies is confounded by the effects of common comorbidities that also contribute to the development of chronic wounds. A lack of quantitative biomarkers of wound healing and age-related changes makes understanding structure-function relationships during the wound healing process challenging. Future Directions: Additional work is needed to establish quantitative and mechanistic relationships among age-related changes in the skin microstructure, mechanical function, and the cellular responses to wound healing.

Difference between the biologic and chronologic age as an individualized indicator for the skin care intensity selection: skin topography and immune system state studies, parameter correlations with age difference

Background

Present research addresses the issue of skin aging and corresponding skin treatment individualization. Particular research question was on the developing of simplified criterion supporting patient-specific decision on the necessity and intensity of skin treatment. Basing on the published results and a wide pool of experimental data, we have formulated a hypothesis that a difference between biologic and chronologic age can be used as an express criterion of skin aging.

Methods

In present paper, we report the results of studies with 80 volunteers between 15 and 65 years of age, linking parameters reflecting immune state, skin state, and topography to the difference between biologic and chronologic age. Facial skin topography, skin moisture, sebum level, and skin elasticity were studied using commercial devices. Blood immunology studies were performed using venous blood samples. Correlations between all measured parameters and age difference were calculated. Also, cross correlations between skin cell profile and blood immune profile parameters, and skin roughness parameters were calculated.

Results

Age dependencies of the blood immunological parameters on the biologic and chronologic age difference are less pronounced as compared to the changes in skin cell profile parameters. However, the changes in the tendencies when biologic age becomes equal to chronologic one are visible for all studied parameters.

All measured skin roughness parameters show correlations with age difference, but average skin roughness and depth of the deepest profile valley have the largest correlation coefficient values. Many of the measured skin cell profile and blood immunology parameters show strong correlations with average skin roughness and deepest profile valley, with some of the coefficients exceeding 0.5–0.6.

Conclusions

Basing on own experiments and published research results, it is possible to suggest using the difference between calculated biologic age and chronologic age as an individualized criterion supporting decisions on skin treatment strategy. Further research involving larger numbers of participants and aiming on optimizing the expressions for calculating biologic age could lead to reliable and easily available express criterion supporting the decision making for an individualized skin treatment.

Difference between the biologic and chronologic age as an individualized indicator for the skincare intensity selection: skin cell profile and age difference studies

Background

The present research addresses the issue of skin aging and corresponding skin treatment individualization. Particular research question was on the development of a simplified criterion supporting patient-specific decisions about the necessity and intensity of skin treatment. Basing on published results and a wide pool of our own experimental data, a hypothesis is formulated that a difference between biologic and chronologic age can be used as a powerful indicator of skin aging.

Methods

In the present paper, we report the results of studies with 80 volunteers between 15 and 65 years of age linking skin cell profile parameters to biologic and chronologic age. Biologic age was calculated using the empirical expressions based on the forced vital lung capacity, systolic blood pressure, urea concentration, and blood cholesterol level. Epidermis and derma cellular structures were studied using skin biopsy samples taken from the gluteal region.

Results

The present study supports the conclusion that biologic and chronologic age difference is changing in the progress of life. Our studies are showing that time point when calculated biologic age becomes equal to the chronologic one reflecting the onset of specific changes in the age dependencies of experimentally measured skin cell profile parameters. Thus, it is feasible that a difference between chronologic and individually assessed biologic age indeed reflects the process of skin aging.

Conclusions

With all reservations to the relatively small number of study participants, it seems feasible that a difference between biologic and chronologic age can be used as an indicator of skin aging. Additional research linking blood immune profile and skin topography to the difference of biologic and chronologic age (reported in the following paper) provides further support for the formulated hypotheses. So, a difference between calculated biologic age and chronologic age can be used as an individualized criterion supporting decisions on skin treatment strategies. Further research involving larger numbers of participants aimed at optimizing the expressions for calculating biologic age could lead to reliable and easily available express criterion supporting the decision for the individualized skin treatment.

In vivo determination of the skin surface topography and biophysical properties of human hands: Effects of sex and hand dominance

BACKGROUND

The effect of hand dominance on the skin topography and parameters associated with skin health and aging is unknown.

METHODS

Healthy adult volunteers were recruited. The following four strata were enrolled: Group 1: male, right handed; Group 2: male, left handed; Group 3: female, right handed; and Group 4: female, left handed. The differences between groups on their surface evaluation of living skin (SELS) parameters were evaluated. These variables included (a) roughness (SER); (b) smoothness (SESM); (c) scaliness (SESC); and (d) wrinkles (SEW).

RESULTS

A total of twenty subjects were recruited, with five in each stratum. Significant differences between groups were found for SESC [F(7,31) = 2.742, P = .024, partial eta squared = 0.382] and SEW [F(7,31) = 3.705, P = .005, partial eta squared = 0.456]. An evaluation of the descriptive statistics revealed that males had a higher mean SESC value than females and a lower mean SEW value. Moreover, the dominant hand of both sexes had a higher mean SEW value than non-dominant hands.

CONCLUSIONS

Given the evidence of sex and handedness differences in wrinkle genesis and desquamation severity, these factors should be considered in the dermatological treatment and counseling of patients.

Surface Evaluation of Living Skin (SELS) parameter correlation analysis using data taken from astronauts working under extreme conditions of microgravity

BACKGROUND

In space, due to fluid shift a 45% decrease in the skin topography parameter volume (mm³ ) was seen using the VisioScan^® camera. Simultaneously, the parameters roughness, scaling and wrinkles changed dramatically as well. Thus, the present study has the objective to understand the relationship between the SELS parameters under extreme conditions and their application by addressing scientific-dermatological questions.

MATERIAL AND METHODS

SELS measurements were performed on the volar forearms of six astronauts. The Pearson correlation coefficient was used to determine the association between the variables.

RESULTS

A significant correlation was found between the skin topography parameter volume and the skin parameters roughness, scaling and wrinkles. A closer look at each astronaut revealed a significant correlation for all astronauts for the parameters volume and roughness and for more than 65% of the astronauts for the parameters volume and scaling and volume and wrinkles. However, no correlation could be found between the parameters skin hydration and roughness and scaling, respectively.

CONCLUSION

Only the parameter skin volume leads to meaningful data under microgravity. Physiological changes observed by fluid shift are comparable to the skin condition edema on earth. Based on the obtained data, we can conclude that the formulas for the SELS parameters roughness, scaling and wrinkles for this special skin condition need to be reviewed.

Skin Aging Estimation Scheme Based on Lifestyle and Dermoscopy Image Analysis

Besides genetic characteristics, people also undergo a process of skin aging under the influence of diverse factors such as sun exposure, food intake, sleeping patterns, and drinking habits, which are closely related to their personal lifestyle. So far, many studies have been conducted to analyze skin conditions quantitatively. However, to describe the current skin condition or predict future skin aging effectively, we need to understand the correlation between skin aging and lifestyle. In this study, we first demonstrate how to trace people’s skin condition accurately using scale-invariant feature transform and the color histogram intersection method. Then, we show how to estimate skin texture aging depending on the lifestyle by considering various features from face, neck, and hand dermoscopy images. Lastly, we describe how to predict future skin conditions in terms of skin texture features. Based on the Pearson correlation, we describe the correlation between skin aging and lifestyle, and estimate skin aging according to lifestyle using the polynomial regression and support vector regression models. We evaluate the performance of our proposed scheme through various experiments.

Age estimation based on visual parameters of the skin of cadavers

BACKGROUND

Previous studies have reported relationships between various visual parameters of the skin and changes due to aging. Due to an increase in the discovery of unidentified bodies, the field of forensic medicine anticipates the development of a rapid method for estimating age. The present study measured various visual parameters of the skin in human remains and investigated the correlation between these parameters and age.

MATERIALS AND METHODS

Skin images were taken of four body parts (cheek, chin, brachium, and thigh) of 414 forensic cases. We interpreted eight visual parameters of the skin (smoothness, roughness, texture, dullness, brightness, erythema, color phase, and sagging) from skin photograph images, and constructed three age-prediction models, categorized by sex, postmortem interval, and age.

RESULTS

Significant correlations were observed in the erythema of the cheek and chin, the roughness of the brachium, and the texture of the brachium and thigh among the visual parameters calculated in four body parts, using the three models. The root-mean-square errors, which indicate the precision of the three prediction models, were 13.06, 13.80, and 13.77. The only model that demonstrated a correlation with the visual parameters was sex (but not age or postmortem interval).

CONCLUSION

Similar to living subjects, we observed a correlation with age for a number of visual parameters. The parameters that correlate with age depend on whether the site being measured was exposed to sunlight. Age estimation based on visual parameters requires measurement of visual parameters for skin both exposed and not exposed to sunlight.

Micro-relief analysis with skin capacitive imaging

BACKGROUND

In this study, the performance of capacitive imagining in skin micro-relief analysis was investigated. This measurement principle has been used for skin hydration measurements over the last decade and it is commercially available by various manufacturers. Strengthening its potential for new applications could offer an affordable and portable multi-purpose device for in vivo skin research. Previous studies in the literature have used a wide range of optical devices to determine how the skin surface topographic features are affected by chronological age, environmental influences and living habits.

MATERIAL AND METHODS

A capacitive system was used in order to capture hydration images from the middle volar forearm of twelve volunteers. The visual output of the system was studied and image processing algorithms were adapted to automatically extract skin micro-relief features. The change in the skin network of lines during arm extension, the lines' anisotropy index and the number of closed polygons per skin surface area were plotted against the subjects' chronological age. The results were compared with optical measurements from the literature to validate our algorithms and evaluate the capacitive imaging in skin micro-relief analysis.

RESULTS

The change in the intensity of primary and secondary lines during arm extension and the number of closed polygons per surface area were in agreement with the literature. The anisotropy index output gave inconclusive results.

CONCLUSIONS

The experimental results show that the capacitive systems could only extract two-dimensional skin topographic features.

Influence of facial threading on various physiological parameters of the skin: non-randomized trial involving adult women in Taiwan

BACKGROUND

Facial threading involves the removal of hairs to restore facial skin smoothness. However, its effectiveness has not been rigorously evaluated.

OBJECTIVE

To evaluate effects of facial threading on skin roughness, hydration, melanin index, and vellus hair on the face, complemented by a subjective evaluation of the tactile feel of the skin and improvement in skin color.

METHOD

Participants who had not used exfoliators for two weeks before the experiment were included. Each participant underwent one session of facial threading every 21 days, for a total of 3 sessions. A three-dimensional skin roughness instrument and a multifunctional skin testing system were used to evaluate changes in roughness, hydration, and pigmentation on the forehead, cheeks, and corners of the mouth. A photomicrographic camera was used to record changes in vellus hair. Subjective reports of skin smoothness and color were recorded.

RESULT

Eighteen participants completed the study. Facial threading produced a significant decrease in skin roughness on the forehead (22.42%, p = .013), right cheek (77%, p = .02), and left corner of the mouth (33.02%, p = .001). Subjective improvement in tactile feel of the skin and coloring were reported.

STUDY LIMITATIONS

The study did not include randomization, with further limitations of a small sample size and a single site.

CONCLUSION

Facial threading reduced skin roughness by 26.74% after three threading sessions, with improved subjective assessment of tactile feel and coloring. Future research should include a comparison with other cosmetic products with similar beautifying effects or a control group.

An updated review of clinical methods in the assessment of ageing skin - New perspectives and evaluation for claims support

With the advancement of skin research, today's consumer has increased access to an informed understanding of ageing skin and its appendages, together with a plethora of targeted products to meet such needs. In recent years, increased legislative demands for quality evidential claims support have led not only to the development and validation of clinical methods to measure and quantify ageing skin, but also a clearer understanding of the skin ageing process-especially the impact of both its internal and external environments-as well as a tougher stance on clearly unjustifiable claims. Traditional testing methods used to research and evaluate anti-ageing products claim to employ sophisticated instruments. Today, however, since the term anti-ageing can be considered a misnomer, intelligent use of combined more advanced clinical methods has enabled the development of technologically improved consumer products providing enhanced efficacy and targeted performance. Non-invasive methods for the assessment and quantification of the causes of ageing skin provide tools to the clinical researcher as defined by key clinically observed ageing parameters. Where evidence requires additional support, a number of clinical procedures evaluating ageing skin and hair products are combined with invasive procedures, thus enabling an added value to product claims. As discussed herein, given the enhanced understanding of ageing, we provide an update to our previous reviews of clinical methods used in the assessment of skin ageing, to include the wider aspects of environmental exposure; skin pigmentation; microbiome disturbance; surface topography; colour, radiance, and pH; and structural integrity-all requiring a disciplined approach to their use in dermatological investigations and product claims evidence.

Evaluation of sex-related changes in skin topography and structure using innovative skin testing equipment

BACKGROUND

Evaluation of skin condition on the basis of parametrization and objective measurements of the parameters has become obligatory. The aim of this study was to assess sex-related changes in skin topography and structure using the skin testing equipment.

MATERIALS AND METHODS

The study was carried out on the group of 40 volunteers (20 females and 20 males) of the mean age 24 ± 3 years. The skin parameters were measured using 3 devices: Visioscan^®  VC 98 (skin topography), Visioline^® VL 650 (skin macro relief) and Ultrascan UC22 (ultrasound imaging of the skin). All measurements were performed on the inner part of the left forearm.

RESULTS

The skin parameters measured revealed significant differences in skin surface and structure between females and males. The skin of all women subjects was more homogenous in its structure with the presence of more abundant superficial skin lines and wrinkles in comparison to male skin. The higher number of skin furrows in the skin of women is in agreement with literature reports claiming that men's skin has lower number of wrinkles which are deeper and more pronounced. Ultrasound imaging of the skin indicated greater thickness and lower density of the dermis of men subjects compared to those of females.

CONCLUSION

Non-invasive methods of skin testing using new and advanced equipment have provided a possibility of objective parametrization and evaluation of sex-related changes in skin topography and structure.

Roughness preserving filter design to remove spatial noise from stereoscopic skin images for stable haptic rendering

BACKGROUND/PURPOSE

A problem in skin rendering with haptic feedback is the reconstruction of accurate 3D skin surfaces from stereo skin images to be used for touch interactions. This problem also encompasses the issue of how to accurately remove haptic spatial noise caused by the construction of disparity maps from stereo skin images, while minimizing the loss of the original skin roughness for cloning real tough textures without errors. Since the haptic device is very sensitive to high frequencies, even small amounts of noise can cause serious system errors including mechanical oscillations and unexpected exerting forces. Therefore, there is a need to develop a noise removal algorithm that preserves haptic roughness.

METHODS

A new algorithm for a roughness preserving filter (RPF) that adaptively removes spatial noise, is proposed. The algorithm uses the disparity control parameter (λ) and noise control parameter (k), obtained from singular value decomposition of a disparity map. The parameter k determines the amount of noise to be removed, and the optimum value of k is automatically chosen based on a threshold of gradient angles of roughness (R_a ).

RESULTS

The RPF algorithm was implemented and verified with three real skin images. Evaluation criteria include preserved roughness quality and removed noise. Mean squared error (MSE), peak signal to noise ratio (PSNR), and objective roughness measures R_a and R_q were used for evaluation, and the results were compared against a median filter. The results show that the proposed RPF algorithm is a promising technology for removing noise and retaining maximized roughness, which guarantees stable haptic rendering for skin roughness.

CONCLUSION

The proposed RPF is a promising technology because it allows for any stereo image to be filtered without the risk of losing the original roughness. In addition, the algorithm runs automatically for any given stereo skin image with relation to the disparity parameter λ, and the roughness parameters R_a or R_q are given priority. Although this method has been optimized by graph-cut disparity map building, it can be extended to other disparity map building methods because the parameter k is determined by actual roughness R_a data that can be obtained by simple measurement.

Fragility of epidermis in newborns, children and adolescents

Within their first days of life, newborns' skin undergoes various adaptation processes needed to accommodate the transition from the wet uterine environment to the dry atmosphere. The skin of newborns and infants is considered as a physiological fragile skin, a skin with lower resistance to aggressions. Fragile skin is divided into four categories up to its origin: physiological fragile skin (age, location), pathological fragile skin (acute and chronic), circumstantial fragile skin (due to environmental extrinsic factors or intrinsic factors such as stress) and iatrogenic fragile skin. Extensive research of the past 10 years have proven evidence that at birth albeit showing a nearly perfect appearance, newborn skin is structurally and functionally immature compared to adult skin undergoing a physiological maturation process after birth at least throughout the first year of life. This article is an overview of all known data about fragility of epidermis in 'fragile populations': newborns, children and adolescents. It includes the recent pathological, pathophysiological and clinical data about fragility of epidermis in various dermatological diseases, such as atopic dermatitis, acne, rosacea, contact dermatitis, irritative dermatitis and focus on UV protection.

Skin friction related behaviour of artificial turf systems

The occurrence of skin friction related injuries is an issue for artificial turf sports pitches and remains a barrier to their acceptance. The purpose of this study was to evaluate the current industry standard Securisport® Sports Surface Tester that measures skin surface related frictional behaviour of artificial turf. Little research has been published about the device and its efficacy, despite its widespread use as a standard FIFA test instrument. To achieve a range of frictional behaviours, several "third generation" (3G) carpet and infill combinations were investigated; friction time profiles throughout the Securisport rotations were assessed in combination with independent measurements of skin roughness before and after friction testing via 3D surface scanning. The results indicated that carpets without infill had greatest friction (coefficients of friction 0.97-1.20) while those completely filled with sand or rubber had similar and lower values independent of carpet type (coefficient of friction (COF) ≈0.57). Surface roughness of a silicone skin (s-skin) decreased after friction testing, with the largest change on sand infilled surfaces, indicating an "abrasive" polishing effect. The combined data show that the s-skin is damaged in a surface-specific manner, thus the Securisport COF values appear to be a poor measure of the potential for skin abrasion. It is proposed that the change in s-skin roughness improves assessment of the potential for skin damage when players slide on artificial turf.

Developmental Changes in Skin Barrier and Structure during the First 5 Years of Life

The structure of the stratum corneum (SC) and the corresponding skin barrier develops from before birth up to about 4 years of age. Large subject-to-subject variability within an age group requires a large population to observe trends in skin barrier properties over time. Barrier function, quantified by transepidermal water loss (TEWL) and SC thickness, was measured on the upper inner arm and dorsal forearm in subjects aged 3 months to 4 years (n = 171) and a subset of mothers (n = 44). The rate of skin surface area expansion as a function of age peaked before birth (∼90 cm2/week) and declined to a steady plateau (∼10 cm2/week) by 1 year of age. SC thickness increased and TEWL decreased, but did not reach adult values until 3-4 years of age. A better understanding of how skin hydration changes after birth suggests that barrier function may be related mechanistically to skin surface area expansion.

Characterizing facial skin ageing in humans: disentangling extrinsic from intrinsic biological phenomena

Facial skin ageing is caused by intrinsic and extrinsic mechanisms. Intrinsic ageing is highly related to chronological age. Age related skin changes can be measured using clinical and biophysical methods. The aim of this study was to evaluate whether and how clinical characteristics and biophysical parameters are associated with each other with and without adjustment for chronological age. Twenty-four female subjects of three age groups were enrolled. Clinical assessments (global facial skin ageing, wrinkling, and sagging), and biophysical measurements (roughness, colour, skin elasticity, and barrier function) were conducted at both upper cheeks. Pearson's correlations and linear regression models adjusted for age were calculated. Most of the measured parameters were correlated with chronological age (e.g., association with wrinkle score, r = 0.901) and with each other (e.g., residual skin deformation and wrinkle score, r = 0.606). After statistical adjustment for age, only few associations remained (e.g., mean roughness (R z ) and luminance (L (*)),  β = -0.507, R (2) = 0.377). Chronological age as surrogate marker for intrinsic ageing has the most important influence on most facial skin ageing signs. Changes in skin elasticity, wrinkling, sagging, and yellowness seem to be caused by additional extrinsic ageing.