The influences of skin visco-elasticity, hydration level and aging on the formation of wrinkles: a comprehensive and objective approach

Combinatorial application of dissolving microneedle patch and cream for improvement of skin wrinkles, dermal density, elasticity, and hydration

BACKGROUND

Dissolving microneedles (DMNs), microscale needles with a biodegradable polymer matrix, have been widely investigated for transdermal drug delivery. However, the restricted drug loading space of DMNs limited the delivery of the desired quantity of active compounds. In this study, we developed novel combinatorial therapies involving sequential application of adenosine-loaded DMN (Ad-DMN) patches and a topical adenosine-loaded cream (Ad-cream). The application of DMNs created skin channels, which delivered encapsulated drugs from both the DMNs and cream. The use of combinatorial therapies can maximize drug delivery.

METHODS

To compare the efficacy of combinatorial therapies and Ad-cream application, a double-blind clinical test was conducted over 10 weeks on 21 females with wrinkles around their eyes, and the skin parameters such as wrinkles, dermal density, elasticity, and hydration were analyzed. The skin irritation test was assessed by expert interviewers to elucidate undesirable side effects.

RESULTS

The combinatorial therapies showed statistically significant efficacy for the improvement of average depth of wrinkles, dermal density, elasticity, and hydration after an 8-week application (P < 0.001). Adverse effects on the skin were not observed in any subject during the test period.

CONCLUSION

The efficacy and safety results showed that the combinatorial therapies were a safe and outstanding innovation for the optimization of transdermal therapy.

Adenosine-loaded dissolving microneedle patches to improve skin wrinkles, dermal density, elasticity and hydration

OBJECTIVE

Although dissolving microneedle patches have been widely studied in the cosmetics field, no comparisons have been drawn with the topical applications available for routine use. In this study, two wrinkle-improving products, adenosine-loaded dissolving microneedle patches and an adenosine cream, were evaluated for efficacy, with respect to skin wrinkling, dermal density, elasticity, and hydration, and safety in a clinical test on the crow's feet area.

METHODS

Clinical efficacy and safety tests were performed for 10 weeks on 22 female subjects with wrinkles around their eyes. The adenosine-loaded dissolving microneedle patch was applied once every 3 days, in the evening, for 8 weeks to the designated crow's feet area. The adenosine cream was applied two times per day, in the morning and evening, for 8 weeks to the other crow's feet area. Skin wrinkling, dermal density, elasticity, and hydration were measured by using PRIMOS^® premium, Dermascan^® C, Cutometer^® MPA580, and Corneometer^® CM 825, respectively. In addition, subjective skin irritation was evaluated by self-observation, and objective skin irritation was assessed through expert interviews.

RESULTS

The adenosine-loaded dissolving microneedle patches had a similar or better efficacy than the adenosine cream. Both groups showed statistically significant efficacy for almost all parameters (P < 0.05). The dissolving microneedle patches had a long-lasting effect on the average wrinkle depth (P < 0.05), only showed efficacy in dermal density (P < 0.05), had an early improving effect on elasticity (P < 0.05), and demonstrated better hydration efficacy (P < 0.001). No adverse effects were observed in either group during the test period.

CONCLUSIONS

In the clinical efficacy test of four skin-improvement parameters, adenosine-loaded dissolving microneedle patches showed the same or better effect than the adenosine cream, although the weekly adenosine dose was 140 times lower. The dissolving microneedle patches caused no adverse reactions. These adenosine-loaded dissolving microneedle patches are expected to be safe, effective, and novel cosmetics for skin improvement.

Two-phase delivery using a horse oil and adenosine-loaded dissolving microneedle patch for skin barrier restoration, moisturization, and wrinkle improvement

BACKGROUND

Dissolving microneedles (DMNs) have been used for skin restoration and wrinkle improvement. Although lipophilic compounds, for example, natural oils or ceramides, enrich the skin barrier, their delivery via DMNs is challenging because of DMN fabrication difficulties.

OBJECTIVES

In the present study, we combined a topical formulation and a DMN patch to perform two-phase delivery comprising a lipophilic formulation and hydrophilic compound-loaded DMNs to improve skin barrier status and the efficacy of drug delivery.

METHODS

Horse oil-spread and adenosine-loaded DMN arrays were developed in a single patch (HOS-Ad-DMN patch). In vitro analysis was conducted to confirm the successful delivery of the compositions. Clinical assessments were conducted on the lateral canthus of 20 women to compare the efficacy of HOS-Ad-DMN patches with that of adenosine-loaded DMN patches (Ad-DMN patches).

RESULTS

Adenosine was delivered via the DMNs after skin penetration and horse oil was delivered successfully into the skin through the microchannels created by the Ad-DMNs. Compared with Ad-DMN patches, HOS-Ad-DMN patches significantly improved skin elasticity, hydration, dermal density, and wrinkles. No adverse events were observed.

CONCLUSION

HOS-Ad-DMN patches are a safe and efficient system for skin restoration and wrinkle improvement.

Aging-like physiological changes in the skin of Japanese obese diabetic patients

Objective:

Obesity-associated diabetes causes aging-like changes to skin physiology in animal models, but there have been no clinical studies focusing on human obese diabetic patients. The purpose of this study was to examine the hypothesis that obesity-associated diabetes accelerates aging-like skin changes in Japanese people.

Methods:

This cross-sectional study enrolled obese-diabetes patients (body mass index ≥ 25 kg m−2) and healthy volunteers (body mass index < 25 kg m⁻²) as controls. Skin physiology parameters relating to aging (stratum corneum hydration, transepidermal water loss, skin pH, advanced glycation end-products, and dermal collagen density) were evaluated in the two groups.

Results:

About 37 subjects participated (16 in a control group and 21 in an obese-diabetes group). Age was not significantly different between the groups. The stratum corneum hydration level was significantly lower in the obese-diabetes group. Transepidermal water loss and levels of advanced glycation end-products were significantly higher in this group. Skin pH was not significantly different between groups. Dermal collagen density decreased in the obese-diabetes group.

Conclusion:

We showed that obese-diabetes patients have decreased stratum corneum hydration, increased transepidermal water loss, higher skin advanced glycation end-products and decreased dermal collagen fiber density compared with normal-weight subjects. These results indicate that the ordinary age-related physiological skin changes seen in the elderly can also occur in obese-diabetes patients aged in their 40s.

Visualization of viscoelastic behavior in skin equivalent using optical coherence tomography-based straingraphy

BACKGROUND/PURPOSE

The relationships between the skin components and these mechanical roles are still unclear. To clarify these relationships, we investigated spatial mapping of the mechanical behavior of cultured skin equivalents (SEs) using optical coherence tomography (OCT)-based straingraphy.

METHODS

We built a strain relaxation test system combined with OCT and developed an algorithm that could visualize a time-dependent strain distribution, named dynamic-optical coherence straingraphy (D-OCSA). Using this system, we analyzed how the spatial mechanical changes in the SEs depended on the culture duration. For quantitative analysis of viscoelastic behavior, we defined a relaxation attenuation coefficient of strain rate, which indicates the ratio of viscosity and elasticity in the Klevin-Voight model.

RESULTS

By culturing for 4 days in comparison to culturing for 1 day, the strain relaxation attenuation coefficient of the whole skin, especially at the region of the dermal-epidermal junction (DEJ), significantly increased in the negative direction. In tissue slices taken for microscopy, several cracks were observed in the SEs cultured for 4 days.

CONCLUSION

This study is the first to provide quantified evidence that the DEJ is a dynamically specialized region. An OCT-based straingraphy system (D-OCSA) would be beneficial for evaluating the quality of SEs, as well as functional analysis of their mechanics.

Claimed Effects, Outcome Variables and Methods of Measurement for Health Claims Proposed Under European Community Regulation 1924/2006 in the Framework of Maintenance of Skin Function

Evidence suggests a protective role for several nutrients and foods in the maintenance of skin function. Nevertheless, all the requests for authorization to use health claims under Article 13(5) in the framework of maintenance of skin function presented to the European Food Safety Authority (EFSA) have received a negative opinion. Reasons for such failures are mainly due to an insufficient substantiation of the claimed effects, including the choice of inappropriate outcome variables (OVs) and methods of measurement (MMs). The present paper reports the results of an investigation aimed at collecting, collating and critically analyzing the information with relation to claimed effects (CEs), OVs and MMs related to skin health compliance with Regulation 1924/2006. CEs, OVs and MMs were collected from both the EFSA Guidance document and from the authorization requests of health claims under Article 13(5). The critical analysis of OVs and MMs was based on a literature review, and was aimed at defining their appropriateness (alone or in combination with others) in the context of a specific CE. The results highlight the importance of an adequate choice of OVs and MMs for an effective substantiation of the claims.

Assessment of age- and sex-related changes in baggy lower eyelids using a novel objective image analysis method: Orbital gray scale analysis

BACKGROUND

Baggy lower eyelids (BLEs) are a common aesthetic problem of aging. Valid and reliable assessment tools for BLEs are required to evaluate the current status and treatment outcome.

AIMS

Age- and sex-related changes in BLEs were assessed with the orbital gray scale (OGS), a novel objective image analysis method.

METHODS

We gathered frontal-view photographs of the faces of the patients who sought for correction of BLEs. Based on the clinical pattern, we classified the BLEs of the subjects into medial (M), medial and central (MC), and medial to lateral (MCL) types. Severity was evaluated using the OGS, a modified method of the linear gray scale analysis.

RESULTS

The BLEs of 1034 subjects were classified. The most common types were MCL type in the men and MC type in the women, respectively. The M and MC types were common in the young subjects, whereas the MCL type was more common in the old subjects (P < .001). The measurements of OGS in 104 subjects showed positive correlation with age, a higher mean value in the men, and a trend toward higher values in the order of M, MC, and MCL types (P < .001 for central and lateral OGS scores). In a multiple linear regression analysis, central and lateral OGS values were significantly related with age, sex, and M-C-L classification type (P < .001).

CONCLUSION

The M-C-L classification and OGS were significantly associated with both age and sex, proving that they could be potent objective assessment tools for BLEs.

Forearm skin aging: characterization by instrumental measurements

BACKGROUND

The intrinsic ageing and photoaged skin present biomechanical and morphological differences, which are reflected in the appearance of roughness, superficial and deep wrinkles, atrophy, reduced elasticity, hypo- and hyperpigmentation and actinic keratosis.

OBJECTIVE

To evaluate and compare the characteristics of the flexor (with a predominance of intrinsic ageing) and extensor (chronically exposed to sunlight and other environmental factors, with a predominance of photoageing) skin surfaces of the forearms.

METHODS

Interventional, prospective, diagnostic study, including 23 females, aged over 60 years. The extensor and flexor faces of forearms were compared in relation to clinical parameters and non-invasive instrumental measurements, such as skin surface, elasticity, hydration as well as dermal thickness and echogenicity.

RESULTS

Regarding the water content of the stratum corneum, the flexor face presented an average value higher than the extensor face. The average of measures obtained through images of high-frequency ultrasound demonstrated greater echogenicity of flexor face compared to the extensor face. The measurements of the skin surface showed significant differences between the faces. The roughness and scaliness were lower in the flexor face. Regarding the depth of wrinkles, there was no significant difference between the faces. The average of the measurements was slightly higher in the flexor face, which demonstrated that wrinkles are present in the intrinsic ageing and photoageing. The presence of elastosis and the reduction in elasticity in the clinical aspect of the photoaged face of forearms were according to the results of the non-invasive measurements.

CONCLUSION

Meaningful differences in the biophysical characteristics of the extensor and flexor faces of the forearms were detected. Because the non-invasive instrumental measurements correlated with clinical findings, they may represent useful tools to assess efficacy and safety of skin ageing treatments in clinical research.

Mechanisms and Materials of Flexible and Stretchable Skin Sensors

Wearable technology has attracted significant public attention and has generated huge societal and economic impact, leading to changes of both personal lifestyles and formats of healthcare. An important type of devices in wearable technology is flexible and stretchable skin sensors used primarily for biophysiological signal sensing and biomolecule analysis on skin. These sensors offer mechanical compatibility to human skin and maximum compliance to skin morphology and motion, demonstrating great potential as promising alternatives to current wearable electronic devices based on rigid substrates and packages. The mechanisms behind the design and applications of these sensors are numerous, involving profound knowledge about the physical and chemical properties of the sensors and the skin. The corresponding materials are diverse, featuring thin elastic films and unique stretchable structures based on traditional hard or ductile materials. In addition, the fabrication techniques that range from complementary metal-oxide semiconductor (CMOS) fabrication to innovative additive manufacturing have led to various sensor formats. This paper reviews mechanisms, materials, fabrication techniques, and representative applications of flexible and stretchable skin sensors, and provides perspective of future trends of the sensors in improving biomedical sensing, human machine interfacing, and quality of life.

Intense pulsed light (IPL) treatment for the skin in the eye area - clinical and cutometric analysis

OBJECTIVE

The aim of the research was to establish the influence of IPL treatment on skin ageing in the eye area.

MATERIAL AND METHODS

This study included 24 women, aged 38-63 years (mean age was 48.04) with Fitzpatrick skin type II and III who underwent five successive treatment sessions with an IPL in two-week intervals. The Cutometer (Courage + Khazaka electronic) reference test was an objective method for the assessment of the biomechanical properties of the skin. The measurements were made in three places around the eye. The photo documentation was used to compare state of skin before and after three months of treatments. Additionally, patients filled in a questionnaire, which contained questions concerning self-assessment of the procedure effects.

RESULTS

Cutometric analysis showed significant improvement of skin elasticity (statistical significance level is mostly < 0.0001). The comparison of clinical changes in the therapy, based on photo documentation, showed a 25% improvement.

CONCLUSIONS

This treatment was used in order to improve skin elasticity and decrease the amount and depth of wrinkles. It is a non-invasive treatment, with low risk of complications.

Sleep Wrinkles: Facial Aging and Facial Distortion During Sleep

Wrinkles are just one indicator of facial aging, but an indicator that is of prime importance in our world of facial aesthetics. Wrinkles occur where fault lines develop in aging skin. Those fault lines may be due to skin distortion resulting from facial expression or may be due to skin distortion from mechanical compression during sleep. Expression wrinkles and sleep wrinkles differ in etiology, location, and anatomical pattern. Compression, shear, and stress forces act on the face in lateral or prone sleep positions. We review the literature relating to the development of wrinkles and the biomechanical changes that occur in response to intrinsic and extrinsic influences. We explore the possibility that compression during sleep not only results in wrinkles but may also contribute to facial skin expansion.

Nonablative radiofrequency treatment for the skin in the eye area - clinical and cutometrical analysis

OBJECTIVE

The purpose of the research was to evaluate skin elasticity and reduction in the aging eye area after using a nonablative radiofrequency treatment.

MATERIAL AND METHODS

This study included 23 patients, aged 34-58 years with Fitzpatrick skin type II and III. They received five treatment sessions with a nonablative radiofrequency in 1-week intervals. Biomechanical properties of the skin were measured using Cutometer. A photodocumentation was used to compare changes before and after the series of treatment sessions. Additionally, the patients filled in a questionnaire in which they were asked to make a self-evaluation of the procedure.

RESULTS

Cutometrical analysis showed improvement of skin elasticity. Changes in the measurements of R2 and R6 parameters indicate that the statistical significance level is mostly P < 0.0001 for the differences in the measurements. The comparison of clinical changes in the therapy, based on photodocumentation, showed a 33.26% improvement.

CONCLUSIONS

This treatment was used to improve skin tightness and decrease the amount and depth of wrinkles. It is a noninvasive treatment, with low risk of complications. The cutometrical measurements seem to be useful to assess improvement of elasticity of the skin after cosmetology or esthetic dermatology treatments.

Nonablative fractional laser treatment for the skin in the eye area - clinical and cutometric analysis

OBJECTIVE

The purpose of the research was to evaluate skin elasticity and reduction in the aging eye area using a 1410-nm nonablative fractional laser treatment, cutometric measurements and photographic documentation.

MATERIAL AND METHODS

This study included 24 patients (21 women, three men), aged 33-50 years (the average age was 44.6) with Fitzpatrick skin type II and III. They received five successive treatment sessions with a 1410-nm nonablative fractional laser in 2-week intervals. Biomechanical properties of the skin were measured by using Cutometer (Courage+Khazaka electronic). Measurements of skin elasticity were made in three places of the eye area. A photographic documentation was used to compare changes after the series of treatment sessions. Additionally, the patients filled in a survey in which they were asked to make a self-evaluation of the administered procedure.

RESULTS

Cutometric analysis showed a significant improvement of skin elasticity. Changes in the measurements of R2 and R6 parameters indicate that the statistical significance level is mostly P < 0.0001 for the differences in the measurements. The analysis of clinical results of the therapy, using photographic documentation, showed a 47% decrease in the quantity and depth of wrinkles in the eye area.

CONCLUSIONS

A 1410-nm nonablative fractional laser treatment seems to be an effective method aiming at reducing wrinkles in the eye area and improving tightness. Cutometric measurements provide invaluable help in the objective evaluation of the anti-aging treatment and the photographic documentation is an excellent addition to the clinical analysis.

Flexible and Stretchable Physical Sensor Integrated Platforms for Wearable Human-Activity Monitoringand Personal Healthcare

Flexible and stretchable physical sensors that can measure and quantify electrical signals generated by human activities are attracting a great deal of attention as they have unique characteristics, such as ultrathinness, low modulus, light weight, high flexibility, and stretchability. These flexible and stretchable physical sensors conformally attached on the surface of organs or skin can provide a new opportunity for human-activity monitoring and personal healthcare. Consequently, in recent years there has been considerable research effort devoted to the development of flexible and stretchable physical sensors to fulfill the requirements of future technology, and much progress has been achieved. Here, the most recent developments of flexible and stretchable physical sensors are described, including temperature, pressure, and strain sensors, and flexible and stretchable sensor-integrated platforms. The latest successful examples of flexible and stretchable physical sensors for the detection of temperature, pressure, and strain, as well as their novel structures, technological innovations, and challenges, are reviewed first. In the next section, recent progress regarding sensor-integrated wearable platforms is overviewed in detail. Some of the latest achievements regarding self-powered sensor-integrated wearable platform technologies are also reviewed. Further research direction and challenges are also proposed to develop a fully sensor-integrated wearable platform for monitoring human activity and personal healthcare in the near future.

[Methods for measuring skin aging]

Aging affects human skin and is becoming increasingly important with regard to medical, social and aesthetic issues. Detection of intrinsic and extrinsic components of skin aging requires reliable measurement methods. Modern techniques, e.g., based on direct imaging, spectroscopy or skin physiological measurements, provide a broad spectrum of parameters for different applications.

Analysis of the complementary measurement of nasogenian wrinkles using Radiocef 2.0® software in the evaluation of facial chronoaging among women of different age groups

Objective : To evaluate the facial aging of women of different ages using a software program to assist in the classification of wrinkles and sagging in the nasogenian region. Method : A descriptive observational study of 100 female volunteers was performed. The women were aged between 20 and 70 years old and were sorted by age group into five groups of 20 volunteers each. The instruments used were the Facial Assessment Protocol, a cephalostat for the standardization of photos, a 14.1 megapixel Sony digital camera, and the Radiocef 2.0® software program. The Kolmogorov-Smirnov (KS) test was used for confirmation of normality and all data was statistically analyzed using ANOVA and Tukey's post hoc analysis. The Chi-squared and Pearson's correlation tests were also performed. A significance level of 5% and a p value of ≤0.05 were adopted. Results : It was observed that all age groups had wrinkles in the nasolabial fold region. There was an association between age and the Goglau, Lapiere and Pierard scale. This incidence increased progressively with aging. A moderate correlation (r=0.67) was observed between age and distance from the nasolabial folds, while angle represented only a weak correlation (r=0.3), with the most significant age group that with the shortest distance and the widest angle. Conclusion : The present study demonstrated the importance of the Radiocef 2.0® software program in providing a more detailed analysis of the nasolabial folds. It is therefore a complementary assessment to the Facial Assessment Protocol, representing a research protocol for identifying the effectiveness of treatments and improving the evaluative procedure.

Skin characteristics: normative data for elasticity, erythema, melanin, and thickness at 16 different anatomical locations

BACKGROUND

The clinical use of non-invasive instrumentation to evaluate skin characteristics for diagnostic purposes and to evaluate treatment outcomes has become more prevalent. The purpose of this study was to generate normative data for skin elasticity, erythema (vascularity), melanin (pigmentation), and thickness across a broad age range at a wide variety of anatomical locations using the Cutometer(®) (6 mm probe), Mexameter(®) , and high-frequency ultrasound in a healthy adult sample.

METHODS

We measured skin characteristics of 241 healthy participants who were stratified according to age and gender. Sixteen different anatomical locations were measured using the Cutometer(®) for maximum skin deformation, gross elasticity, and biological elasticity, the Mexameter(®) for erythema and melanin, and high-frequency ultrasound for skin thickness. Standardized measurement procedures were applied for all participants.

RESULTS

The means and standard deviations for each measured skin characteristic for females and males across five different age groups (20-29, 30-39, 40-49, 50-59, 60-69, and 70-85 years old) are presented. As previously described, there were variations in skin characteristics across age groups, anatomical locations, and between females and males highlighting the need to use site specific, age and gender matched data when comparing skin characteristics.

CONCLUSION

The reported data provides normative data stratified by anatomical location, age, and gender that can be used by clinicians and researchers to objectively determine whether patients' skin characteristics vary significantly from healthy subjects.

The effect of probe placement on inter-trial variability when using the Cutometer MPA 580

There is limited data independently assessing the optimal use of the Cutometer MPA580. The purpose of this study is to test the hypothesis that the assessment of elastic recoil is significantly different when utilizing two different probe placement protocols. In protocol A, four trials were performed, in which the probe was removed from the skin between trials. In protocol B, the probe was not removed from the skin between trials. Fifty-four patients were enrolled and all completed the testing. When assessing elasticity (Ua/Uf), the inter-class correlation was 0.83 for protocol A and 0.48 for protocol B (p <0.001). There was no significant difference between individual trials for protocol A. Trial one of protocol B was significantly different (p < 0.001) than trials 2-4 for protocol B. Trial one of protocol B was not significantly different than any trial in protocol A. The results of this study suggest that the method in which a clinician performs repeated measure testing has a significant effect on the outcome measures when using the Cutometer. Removing the probe between trials appears to result in measures with higher reliability.

Skin barrier dysfunction and low antimicrobial peptide expression in cutaneous T-cell lymphoma

PURPOSE

Atopic dermatitis is characterized by decreased expression of filaggrin and loricrin. Patients with atopic dermatitis often suffer from skin infections, which are also frequently seen in patients with cutaneous T-cell lymphoma (CTCL). In this study, we aimed to investigate the skin barrier in CTCL.

EXPERIMENTAL DESIGN

We assessed skin moisture and transepidermal water loss (TEWL) in patients with CTCL. We next examined mRNA expression levels of filaggrin, loricrin, and antimicrobial peptides (AMP) in skin samples of CTCL, using skin from healthy volunteers and patients with atopic dermatitis or psoriasis as controls. Immunostainings for filaggrin, loricrin, and S100 proteins were also performed.

RESULTS

Lower levels of skin moisture accompanied by higher levels of TEWL were seen in lesional skin of CTCL than in normal skin. CTCL lesional skin contained lower levels of filaggrin and loricrin mRNA than normal skin, which was also true with atopic dermatitis and psoriatic skin. mRNA expression levels of filaggrin in CTCL skin negatively correlated with disease severity markers. Expression levels of AMPs in lesional skin of CTCL and atopic dermatitis were significantly lower than in psoriatic skin. Immunohistochemistry confirmed decreased expression of filaggrin and loricrin in CTCL, atopic dermatitis, and psoriatic skin and enhanced expression of S100 proteins in psoriatic skin.

CONCLUSIONS

Our results show that there is barrier dysfunction in CTCL skin, similar to what is seen with atopic dermatitis skin. In addition, low AMP expression in CTCL skin was documented when compared with psoriatic skin, which may explain frequent infections that can occur in patients with CTCL.

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

BACKGROUND

The topography of the skin surface consists of lines, wrinkles, and scales. Primary and secondary lines form a network like structure that may be identified as polygons. Skin surface roughness measurements are widely applied in dermatological research and practice but the relation between roughness parameters and their anatomical equivalents are unclear. This study aimed to investigate whether the number of closed polygons (NCP) per measurement field can be used as a reliable parameter to measure skin surface topography. For this purpose, we analysed the relation between skin surface roughness parameters and NCP in different age groups.

METHODS

Images of the volar forearm skin of 38 subjects (14 children, 12 younger, and 12 older adults) were obtained with the VisioScan VC98. The NCP was counted by three independent researchers and selected roughness parameters were measured. Interrater reliability of counting the number of closed polygons and correlations between NCP, roughness parameters, and age were calculated.

RESULTS

The mean NCP/mm² in children was 3.1 (SD 1.1), in younger adults 1.0 (SD 0.7), and in older adults 1.0 (SD 0.9). The interrater reliability was 0.9. A negative correlation of NCP/mm² with age was observed, whereas measured roughness parameters were positively associated with age. NCP/mm² was weakly related to skin roughness.

CONCLUSION

The NCP/mm² is a reproducible parameter for characterizing the skin surface topography. It is proposed as an additional parameter in dermatological research and practice because it represents distinct aspects of the cutaneous profile not covered by established roughness parameters.

Reliability and validity of two in vivo measurements for skin surface topography in aged adults

BACKGROUND

The non-contact optical methods phaseshift rapid in vivo measurement of skin (PRIMOS) and surface evaluation of living skin (SELS) are widely applied for measuring skin surface topography. The aims of the present study were to evaluate reliability and validity of these methods and to compare skin roughness intraindividually.

METHODS

SELS and PRIMOS measurements were performed on four skin areas of the left and right volar forearms in 12 healthy elderly subjects. Reliability and correlations were analyzed for Visioscan® and PRIMOS roughness parameters. Student's t-tests for estimating differences between contralateral volar forearm sites were applied.

RESULTS

ICC coefficients of the Visioscan® roughness estimates ranged between 0.50 and 0.95 and of the PRIMOS measurements between 0.01 and 1.00. The Visioscan® parameters SEr, SEsm, Rmax, and Rz, and the PRIMOS parameters Ra, Rz, Smax, Wt, and Sz showed most significant correlations with each other and to additional roughness parameters. Mean roughness differences between contralateral forearm skin areas ranged between 0.0 (SEsc) and 6.7 (Rmax).

CONCLUSIONS

The Visioscan® parameters SEr, Rmax, and Rz showed most reliable and valid values and were largely comparable on contralateral forearm skin sites in elderly subjects. Rmax, Rz, and Ra should be preferred for measuring skin surface topography with PRIMOS.

The science of dermocosmetics and its role in dermatology

Our increased knowledge of normal skin physiology has ushered in a subtle revolution in cosmetic science. Originally designed as preparations to enhance personal appearance by direct application on to the skin, cosmetics have now taken on a new role in dermatology, through the support of the management of many skin disorders. This evolving role of cosmetics in skin care is primarily due to scientific and technological advancements that have changed our understanding of normal skin physiology and how cosmetics modify its appearance both physically and biologically. The vast array of techniques currently available to investigate skin responsivity to multiple stimuli has brought about a new era in cosmetic and dermocosmetic development based on a robust understanding of skin physiology and its varied responses to commonly encountered environmental insults. Most cosmetic research is undertaken on reconstructed skin models crucial in dermatological research, given the strict ban imposed by the European Union on animal testing. In addition, the design and conduct of trials evaluating cosmetics now follow rules comparable to those used in the development and evaluation of pharmaceutical products. Cosmetic research should now aim to ensure all trials adhere to strictly reproducible and scientifically sound methodologies. The objective of this review is to provide an overview of the multidisciplinary scientific approach used in formulating dermocosmetics, and to examine the major advances in dermocosmetic development and assessment, the safety and regulatory guidelines governing their production and the exciting future outlook for these dermocosmetic processes following good practice rules.

The effect of probe to skin contact force on Cutometer MPA 580 measurements

The purpose of this study is to test the hypothesis that increasing the force applied on the skin by the Cutometer MP580 probe will result in a decrease in the skin elasticity measures. Specifically, this study assessed the probe intrinsic weight plus the addition of a light mass (10 g and 20 g), a moderate mass (50 g and 100 g) and a high mass (200 g and 500 g) on skin elasticity measures. Primary outcome measures Uv, Ur, Uf, Ue and Ua, along with calculated measures Uv/Uf, Ua/Uf and Ur/Uf were assessed under each loading condition. A general linear model ANOVA with repeated measures was used to assess for differences in each outcome measure between each loading condition. Thirty-two patients were enrolled and all completed the testing. For all primary variables except Uv (p < 0.001), there was no statistically significant effect of adding a light mass to the probe. There was a significant effect of the addition of a moderate and heavy mass for all variables (p < 0.005) except Ue/Uf. These results suggest that the addition of a low mass results in no significant effect on outcome measures. However, if moderate-to-heavy additional force is applied to the probe, the outcome measures are significantly altered. Of all the variables, Ue/Uf appears to be influenced the least by alterations in force. Users should ensure light contact is made between the skin and probe during testing to avoid a false alteration in outcome measures of skin elasticity.

Epidermal impedance sensing sheets for precision hydration assessment and spatial mapping

This paper presents a class of hydration monitor that uses ultrathin, stretchable sheets with arrays of embedded impedance sensors for precise measurement and spatially multiplexed mapping. The devices contain miniaturized capacitive electrodes arranged in a matrix format, capable of integration with skin in a conformal, intimate manner due to the overall skin-like physical properties. These "epidermal" systems noninvasively quantify regional variations in skin hydration, at uniform or variable skin depths. Experimental results demonstrate that the devices possess excellent uniformity, with favorable precision and accuracy. Theoretical models capture the underlying physics of the measurement and enable quantitative interpretation of the experimental results. These devices are appealing for applications ranging from skin care and dermatology, to cosmetology and health/wellness monitoring, with the additional potential for combined use with other classes of sensors for comprehensive, quantitative physiological assessment via the skin.