EEMCO Guidance for the in vivo Assessment of Biomechanical Properties of the Human Skin and Its Annexes: Revisiting Instrumentation and Test Modes

Biophysical effects of a natural peloid on normal skin

A protocol study was designed to examine cutaneous behavior after continuous application of a peloid in the dry mineral residue of Lanjarón-Capuchina natural mineral water. This study aims to analyze the biomechanical behavior of normal skin using various non-invasive bioengineering techniques after the application of this peloid. We determine the effects of its application for 3 months on 38 healthy volunteers (41.4 ± 5.9 years, range 32-58) without a previous history of skin diseases by courtmetry, sebumetry, pH-metry, reviscometry, and tewametry. It was shown that the production of cutaneous sebum is significantly reduced by 6%, trans epidermal skin loss (TEWL) by 21%, skin fatigue by 30%, elasticity increased by 19%, firmness by 5%, and a skin redensification by 6% was obtained under these experimental conditions. Disparate and non-significant results were obtained concerning pH and viscoelasticity. Continuous skin care with the Lanjarón-Capuchina natural peloid modifies skin behavior, normalizing sebaceous secretion, favoring the biomechanical properties of the skin and the skin barrier function without modifying skin homeostasis.

A quantitative comparison of devices for in vivo biomechanical characterization of human skin

Non-invasive skin characterization devices are emerging as a valuable tool in clinical skin research. In recent years, the range of available experimental techniques and methods used to determine the biomechanical properties of skin has increased considerably. Although a substantial amount of work has been devoted to assessing the working principle of macroscopic skin characterization devices individually, a rationalization and comparison between them is still lacking. This motivated the present study, which aimed to characterize and compare three commonly used working principles: suction, dynamic shear loading, and indentation. A synthetic model system with tunable mechanical properties was used to assess the three devices, and the results rationalized based on corresponding finite element models. In vivo measurements were performed on healthy volunteers to investigate the capability of differentiating the biomechanical properties of skin at different body locations, and to assess the intra- and inter-rater reliability of each device. The present comparative analysis indicates that the analyzed functional principles perceive the stiffness of human skin differently, with relevant implications for the interpretation of the respective measurement results.

Use of a novel indentometer to evaluate skin stiffness in healthy and diseased human skin

BACKGROUND

Mechanical behavior of the skin can be evaluated by different non-invasive methods. In this study, we applied a new measurement device based on indentometry to determine the skin mechanical properties in healthy individuals and in patients with systemic sclerosis (SSc).

MATERIAL AND METHODS

Three studies were performed. Study 1 included 100 healthy individuals (46 male and 54 female) divided into four age groups with mean ages of 21.5, 28.9, 51.2, and 69.3 years, respectively. Test sites were located on the center of the forehead and the middle of both volar forearms. Study 2 included 16 healthy individuals (two males and 14 females). Test sites were on both volar forearms. Measurements were made before and after the application of Vaseline and emulsion with 12% urea. Study 3 included 20 patients (one male and 19 females) with SSc and 60 age-matched healthy individuals (23 males and 37 females). Test sites were on the center of the forehead and the middle of both volar forearms. Skin stiffness was measured with skin Indentometer IDM 800 (Courage + Khazaka, Cologne, Germany) equipped with two probes with pin diameters of 3 and 5 mm, respectively. The stiffer the skin, the less deep the displacement by the indenter. The smaller the diameter, the deeper the pin will go into the skin when using the same force. In addition, the Corneometer CM 820 (Courage + Khazaka) was used to determine epidermal water content in study 2.

RESULTS

Indentometric (IDM) values of healthy subjects measured with both probes were lower on the forehead compared to volar forearms. There was no significant difference between both forearms. In all age groups, the IDM values on the male forearms were lower than on the female forearms whereas there was no significant difference on the forehead. In both sex and on all test locations a significant positive correlation between age and IDM values measured with both probes was observed. There was a significant positive correlation between IDM values measured with both probes. The application of moisturizers induced significant changes in epidermal water content whereas the IDM values remained unchanged. At both the forehead and volar forearms, the IDM values in patients with SSc were significantly lower compared to the healthy control skin.

CONCLUSION

The non-invasive indentometric method used can successfully distinguish the changes in normal skin mechanical properties related to age, sex, and anatomical location, as well as in patients with SSc. The method is not appropriate to study the changes related to epidermal hydration.

The Science of Skin: Measuring Damage and Assessing Risk

Significance: Healthy skin provides a barrier to contaminants. Breaches in skin integrity are often encountered in the patient health care journey, owing to intrinsic health issues or to various procedures and medical devices used. The time has come to move clinical practice beyond mere awareness of medical adhesive-related skin injury and toward improved care and outcomes. Recent Advances: Methods developed in research settings allow quantitative assessments of skin damage based on the measurement of baseline skin properties. These properties become altered by stress and over time. Assessment methods typically used by the cosmetic industry to compare product performance could offer new possibilities to improve clinical practice by providing better information on the status of patient skin. This review summarizes available skin assessment methods as well as specific patient risks for skin damage. Critical Issues: Patients in health care settings may be at risk for skin damage owing to predisposing medical conditions, health status, medications taken, and procedures or devices used in their treatment. Skin injuries come as an additional burden to these medical circumstances and could be prevented. Technology should be leveraged to improve care, help maintain patient skin health, and better characterize functional wound closure. Future Directions: Skin testing methods developed to evaluate cosmetic products or assess damage caused by occupational exposure can provide detailed, quantitative information on the integrity of skin. Such methods have the potential to guide prevention and treatment efforts to improve the care of patients suffering from skin integrity issues while in the health care system.

Non-invasive biomechanical assessment of the prolapsed vaginal wall: an explorative pilot study on cutometry and indentometry

The clinical assessment of pelvic organ prolapse (POP) and associated treatment strategies is currently limited to anatomical and subjective outcome measures, which have limited reproducibility and do not include functional properties of vaginal tissue. The objective of our study was to evaluate the feasibility of using cutometry and indentometry for non-invasive biomechanical assessment of the vaginal wall in women with POP. Both techniques were applied on the vaginal wall of 20 women indicated for surgical correction of POP stage two or higher. The primary outcome was the measurement success rate. Measurements were considered successful if biomechanical parameters were generated after a maximum of three attempts. Secondary outcomes included acquisition time, number of attempts to obtain a successful measurement, and biomechanical parameters. Measurements were successfully performed on the anterior vaginal wall of 12 women with cystocele and the posterior vaginal wall of eight women with rectocele. The success rate was 100% for both techniques and acquisition time was under 1 minute for all 20 measurements. Tissue fast elasticity of the posterior vaginal wall (rectocele) was significantly higher than that of the anterior vaginal wall (cystocele) and negatively correlated with age (r = - 0.57, P < 0.05). In women with POP, measuring the biomechanical properties of the vaginal wall using cutometry and indentometry is technically feasible. Objective evaluation of biomechanical properties may help to understand the pathophysiology behind surgical outcomes, providing an opportunity for the identification of patients at risk for (recurrent) prolapse, and individualized treatment decisions.

Objective Burn Scar Assessment in Clinical Practice Using the Cutometer©: Introduction and Validation of a Standardized Measurement Protocol

An objective burn scar assessment is essential to informed therapeutic decision-making and to monitor scar development over time. However, widely employed scar rating scales show poor inter-rater reliability. For this study we developed a standardized measurement protocol for the Cutometer© applicable for objective burn scar assessment in everyday clinical practice. We developed a measurement protocol for the Cutometer© MPA 580 including a scar site relocation technique based on anatomical landmarks. The protocol emerged through several steps: Identifying key factors for valid and reliable measurements, preliminary testing, specification of technical details, refining the protocol and final testing. Consecutively, the protocol was validated for inter-rater reliability by assessing 34 burn scars in 17 patients by four clinicians and computing an Intra-class Correlation Coefficient (ICC). Parameter R0, representing scar pliability, was identified as the best suited output parameter yielding excellent inter-rater reliability for average measures (ICC 0.92 [95% CI 0.86; 0.96]) and acceptable reliability for single measures (ICC: 0.74 [0.61; 0.84]). The pressure applied on the measuring probe was identified as an influential confounding factor for reliable measurements. Rater gender did not influence reliability of measurements. The introduced standardized measurement protocol for the Cutometer© MPA 580 enables an objective and reliable burn scar assessment for clinical as well as research purposes.

Towards the Development of a Device for Assessing the Pliability of Burn Scars

Burn injuries requires post-accident medical treatment. However, the treatment of burns does not end with first aid because scarred skin must be managed for many years, and in some circumstances, for life. The methods used to evaluate the state of a burn scar based, for instance, on Patient and Observer Scar Assessment Scale or similar ones, often lacks in univocally assessing the scarred skin’s state of health. As a result, the primary aim of this research is to design and build a prototype that can support the doctor during scar assessment, and eventually therapy, by providing objective information on the state of the lesion, particularly the value of skin pliability. The developed tool is based on the depressomassage treatment probe named LPG, currently used to treat burn scars in a number of hospitals. It consists of a non-invasive massage technique using a mechanical device to suction and mobilize scar tissue and is used as a post-operative treatment to speed up the healing process to make the mark of the scar less visible. The prototype is specifically designed to be manufactured using Additive Manufacturing and was validated comparing its performances against the ones of a certified instrument (i.e., the Romer Absolute ARM with RS1 probe). Validation was carried out by designing and developing a tool to put the RS1 probe in the same measurement conditions of the new prototype probe. Tests performed to assess the performance of the devised prototype show that the probe developed in this work is able to provide measurements with a sufficient degree of accuracy (maximum error ±0.1 mm) to be adopted for a reliable estimation of the pliability value in a hospital environment.

Microinjections with hyaluronic acid in combination with glycerol: How do they influence biophysical viscoelastic skin properties?

BACKGROUND

Skin quality improvement with hyaluronic acid microinjections is increasing as a clinical treatment indication and as a scientific issue. This present study assessed changes in biomechanical viscoelastic skin properties after microinjections with the skin quality booster CPM-HA20G (Belotero Revive).

MATERIALS AND METHODS

Fifteen subjects have been randomized in a 2:1 ratio to receive either three treatments (total 3 ml per side) or a single-dose treatment (total 1.5 ml per side) with CPM-HA20G at dermal level into the lower cheeks via microinjections. Treatments were provided 4 weeks apart. Biophysical measurements were performed describing the viscoelastic skin properties and the underlying skin structure. The measurements were performed before injection (week 0) and on follow-up visits 4, 8, 16, 24, and 36 weeks after the last injection treatment.

RESULTS

One (p = 0.028) as well as three (p = 0.003) consecutive treatments with CPM-HA20G improved statistically significant skin firmness (R0). For the multiple-treatment group improved significant differences were observed for skin fatigue (R3; p = 0.007) and skin density (p = 0.017) with stable skin thickness levels (p > 0.05), too. There were zero-to-weak correlations between skin thickness and biomechanical skin properties (R0, r_s  = 0.084; R3, r_s  = 0.093).

CONCLUSION

Overall, microinjections with CPM-HA20G improved biomechanical viscoelastic skin properties with a stronger and more pronounced effect in the multiple-treatment group. The observed changes may explain some of the skin quality improvements observed after treatment with CPM-HA20G.

Changes in the skin characteristics associated with dehydration and rehydration

AbstractThe present study aimed to test the hypothesis that changes in the dermal tissue dielectric constant (TDC) and biomechanical properties of the skin would be correlated with the indicators related to dehydration. Ten healthy adult men were enrolled in three trials: no fluid intake (DEH), ad libitum fluid intake (AL-HYD), and programmed fluid intake (P-HYD) after exercise in a randomized crossover design. The participants performed a pedaling exercise at 60% heart rate reserve until 2% body mass loss. At 120 min after exercise, an incremental exercise test was carried out. Aerobic capacity, body composition, TDC, biomechanical properties of the skin (pliability, viscoelasticity, and total recovery), and indicators related to dehydration in the serum and urine were measured before and 120 min after exercise. Higher values of the pliability and viscoelasticity, and lower value of the total recovery on the hand were demonstrated in the P-HYD trial compared to the DEH trial (all P < 0.05). Changes in the TDC were significantly correlated with changes in body mass (P < 0.05), total body water (P < 0.05), serum osmolarity (P < 0.05), and hematocrit (P < 0.01). Changes in the biomechanical properties of the hand were significantly correlated with changes in body mass, hematocrit, and urine specific gravity (all P < 0.05). The present study showed that the changes in skin characteristics correlated with the body water and dehydration-associated indicators in the serum and urine, thus suggesting that skin characteristics may be useful in the assessment of dehydration.

Ultrasonic microrheology for ex vivo skin explants monitoring: A proof of concept

As an answer to alternative non-animal testing, biosensors dedicated to the ex vivo skin explants monitoring are a challenge to study physiological-like behavior and optimize new topical products. Because of the skin viscoelastic behavior, mechanical tests are commonly based on macroscopic measurement and give global descriptors of its state. Other techniques, including photoacoustic ones, are more focused on the molecular scale. There is a gap to fill in the mesoscopic range to get information about the microstructure of the skin. This article presents the proof-of-concept of a biosensor coupling a thickness shear-mode transducer with human skin explants kept in life-like state for a week. Thanks to a multifrequency analysis of the transducer impedance, this biosensor is able to monitor the viscoelastic properties of the skin. To extract the complex shear modulus and the microstructural evolutions, a mechanical model based on fractional calculus is used. As a preliminary results, the sensitivity of the sensor to probe the skin viscoelasticity in lifelike state and the impact of its culture medium are presented. A suitable microstructural coefficient is also extracted in order to identify mechanical breaches in the skin barrier after the application of peeling products.

Use of a novel Indentometer to evaluate skin induration in localized scleroderma and psoriasis vulgaris

INTRODUCTION

Diseased skin in localized scleroderma (LS) and plaque psoriasis (PPs) is characterized by induration that can be evaluated by non-invasive bioengineering methods. In this study, we applied a new measurement device based on indentometry to determine the changes of skin mechanical properties in patients with LS and PPs.

MATERIAL AND METHODS

A total of 30 sclerodermatous plaques in 12 patients with LS and 46 psoriatic plaques in 19 patients with PPs were measured with Indentometer IDM 800 (Courage + Khazaka, Cologne, Germany). The device measures the penetration depth of the probe indenter (pin) into the skin in mm. We used two probes with pin diameters 3 and 5 mm, respectively. The stiffer the skin, the less deep is the displacement by the indenter. The smaller the diameter, the deeper the pin will go into the skin when using the same force. The measurements were made on diseased skin and in adjacent normal skin served as control. In addition, the psoriatic plaques were measured before and after treatment.

RESULTS

The sclerodermatous skin and the psoriatic skin showed lower Indentometer values compared to adjacent normal skin as measured with both probes. This suggests that diseased skin is stiffer than healthy skin. The values of psoriatic plaques increased after treatment applied that correlates with the clinical improvement. The Indentometric readings significantly negatively correlated with clinical scores of skin induration. There was a significant correlation between the measurements with probe 3 mm and probe 5 mm.

CONCLUSION

The non-invasive method used is appropriate for objective and quantitative determination of the degree of skin induration in LS and PPs as well as for assessment of the disease evaluation and treatment efficacy.

Interrelationships between Skin Structure, Function, and Microbiome of Pregnant Females and Their Newborns: Study Protocol for a Prospective Cohort Study

Background

Pregnancy leads to several skin changes, but evidence about structural and functional skin changes is scarce. Findings on skin structure and function in children in their first year reveal rapid skin maturation, but evidence indicates that in particular, water holding and transport mechanisms are different from adults. Important questions include whether maternal cutaneous properties predict infant skin condition, and if so, how. This is especially relevant for the skin's microbiome because it closely interacts with the host and is assumed to play a role in many skin diseases. Therefore, the study objective is to explore characteristics of skin and hair of pregnant women and their newborns during pregnancy and in the first six months after delivery and their associations.

Methods

The study has an observational longitudinal design. We are recruiting pregnant females between 18 and 45 years using advertisement campaigns in waiting areas of gynecologists and hospital's outpatient services. A final sample size of n = 100 women is the target. We perform noninvasive, standardized skin, hair, and skin microbiome measurements. We establish the baseline visit during pregnancy until at the latest four weeks before delivery. We schedule follow-up visits four weeks and six months after birth for mothers and their newborns. We will calculate descriptive statistical methods using frequencies and associations over time depending on scale levels of the measurements. Discussion. The majority of previous studies that have investigated infants' skin microbiome and its associations used cross-sectional designs and focused on selected characteristics in small samples. In our longitudinal study, we will characterize a broad range of individual and environmental characteristics of mothers and their newborns to evaluate interrelationships with skin parameters and their changes over time. Considering the combination of these multiple variables and levels will allow for a deeper understanding of the complex interrelationship of the newborn's skin maturation. This trial is registered with ClinicalTrials.gov (Identifier: NCT04759924).

Skin biomechanical and viscoelastic properties measured with MyotonPRO in different areas of human body

BACKGROUND

There is still a lack of clinically practical device, which allows to perform rapid and accurate examination of the skin condition. For this reason, suitability of the MyotonPRO for the assessment of skin biomechanical and viscoelastic parameters was evaluated in this study. The aim of the study was to establish the reference values of five parameters measured by MyotonPRO various locations of human skin.

MATERIALS AND METHODS

Oscillation frequency, dynamic stiffness, logarithmic decrement, mechanical stress relaxation and creep were measured at three different skin locations (clavicula, volar forearm and shin), using L-shape short and medium arm probes in 32 young female volunteers. Mean values of obtained parameters recorded by both probes were compared among three skin locations while reliabilities of measurements were assessed. Additionally, relationships between all recorded parameters were examined RESULTS: There were no statistically significant differences between the mean values of five measured parameters obtained with both probes in all investigated areas. However, statistically significant differences of mean values of almost all parameters measured among three places examined were found. Despite considerable differences in mean values of obtained parameters, there were visible strong correlations between some studied parameters in all three investigated areas of skin.

CONCLUSION

It was demonstrated in all locations studied that the higher value of oscillation frequency corresponds to the higher value of dynamic stiffness, moreover such tissue recovers faster to its initial shape, and it was characterized by lower creep values. Such results indicate the existence of identical relationships between the same studied parameters in different areas of skin.

Taxifolin as a Promising Ingredient of Cosmetics for Adult Skin

Active substances, effective in the reduction in or delay of skin changes caused by aging occurring in natural compounds, are desirable. Taxifolin (TXF), a flavonoid of strong antioxidant activity found in the plant Stizolophus balsamita (S. balsamita), has been tested for its biological effects on adult human skin. The aim of the study was to investigate the effects of two creams: 3% S. balsamita extract and 3% TXF on the function of adult skin. In total, 97 Caucasian women with clinical signs of skin aging were investigated. The biophysical and biomechanical skin parameters were measured before and after applying the creams, using Colorimeter CL400, Mexameter MX16, Skin-pH-Meter PH900, Skin-Thermometer ST 500, Glossymeter GL200, and Cutiscan SC100. Patch tests were performed with the investigated products to assess their potential irritant properties. The percutaneous penetration of creams was examined with the use of electrospray ionization mass spectrometry (ESI-MS) and confocal Raman spectroscopy. The 3% S. balsamita extract cream reduced hyperpigmentation, erythema, and elevated pH. All the tested preparations were proven to be nonirritant. A higher penetration rate was revealed for the 3% TXF cream than for the 3% S. balsamita extract cream. A total of 3% TXF cream improved skin viscoelasticity. The obtained results suggested that S. balsamita extract and TXF may be considered as ingredients of skincare products for adults.

Development, Characterization, and Clinical Investigation of a New Topical Emulsion System Containing a Castanea sativa Spiny Burs Active Extract

The study focused on the development and characterization of an O/W emulsion for skincare containing Castanea sativa spiny burs extract (CSE) as functional agent. The emulsion was stable and had suitable physicochemical and technological properties for dermal application and CSE showed no cytotoxicity in spontaneously immortalized keratinocytes (HaCaT) at active concentrations. A single-blind, placebo-controlled, monocentric study was designed to evaluate the skin tolerability and the skin performance of the CSE-loaded emulsion on healthy human volunteers. An improvement was observed in skin biomechanical properties such as hydration, skin elasticity and a reduction in the periorbital wrinkles in 30 days without altering the skin barrier function, sebum, pH, and erythema values. A significant skin moisturizing effect was detected while the skin barrier function was preserved. The selected natural ingredient combined with the designed formulation and the optimized preparation method has led to a final product that satisfies the physico-chemical and technological requirements underlying the safety of use and the formulative stability over time. With no negative skin reactions and highly significant effects on skin elasticity, wrinkles, and moisturization, the CSE-based emulsion achieved very satisfying outcomes representing a promising functional formulation for skin care.

Longitudinal monitoring and prediction of long-term outcome of scar stiffness on pediatric patients

Background

Hypertrophic scarring after burn injury is one of the greatest unmet challenges in patients with burn injuries. A better understanding of the characteristics of scar maturation and early prediction of the long-term outcome of scarring are prerequisites for improving targeted therapies and pivotal for patient counselling.

Methods

Repeated measurements of scar stiffness in 11 pediatric patients were performed over the course of 1 year using 2 suction devices, the Cutometer and the Nimble. In addition, the observer pliability score of the Patient and Observer Scar Assessment Scale was applied. This longitudinal study allowed quantification of the ability of each of the measured parameters to reflect scar maturation, as indicated by change in skin pliability/stiffness, over time (using linear regression); the ability to distinguish individual patients (intraclass correlation coefficient (ICC)); the correlation of the devices (Spearman correlation coefficient); and the ability to predict long-term scar maturation based on early scar assessment (using receiver operating characteristic).

Results

All the tools used showed significant longitudinal decrease of scar stiffness from 3 months until 12 months after the injury. The Nimble (ICC_patient ^Nimble = 0.99) and the Cutometer (ICC_patient ^Cuto = 0.97) demonstrated an excellent ability to distinguish between individual patients. The Nimble seemed to be able to predict the 12-month pliability of scars based on early (3-month) measurements (area under the curve (AUC)_12m ^POSAS = 0.67; AUC_12m ^C = 0.46; AUC_12m ^N = 0.79).

Conclusions

The results of this preliminary study suggest that all 3 tools provide suitable means to quantify alterations in scar stiffness over time. Initial evidence suggests the Nimble is most favorable for predicting changes in stiffness associated with long-term scar maturation. Further studies with a larger sample size are required to validate tissue suction as a clinical tool for analysis of changes of scar stiffness over time.

Skin anisotropy: Finding the optimal incision line for volar forearm in males and females

PURPOSE

Proper understanding of skin biomechanics, viscoelasticity and investigation of skin tension vectors is necessary to find optimal incision lines. Great tension across a healing wound after any surgical procedure might lead to forming hypertrophic scars. The aim of the study was to investigate tension lines in volar forearm skin in young males and females, in order to ensure best incision line.

METHODS

Five biomechanical and viscoelastic parameters were measured using a hand-held myotonometer: Oscillation Frequency [Hz], Dynamic Stiffness [N/m], Logarithmic Decrement of tissue's natural oscillation, Mechanical Stress Relaxation Time [ms], and Creep. Measurements were taken in four different directions; Along Forearm, Across Forearm, Along Langer's Line and Across Langer's Line.

RESULTS

Significant main effects for direction were found for Oscillation Frequency (p < 0.001, η² = 0.371) [Hz], Dynamic Stiffness (p < 0.001, η² = 0.522) [N/m], Logarithmic Decrement (p < 0.001, η² = 0.083), Mechanical Stress Relaxation Time (p < 0.001, η² = 0.494) [ms] and Creep (p < 0.001, η² = 0.480). For each parameter except for logarithmic decrement results obtained Along Langers Line and Across Forearm were significantly different to Across Langers Line and Along Forearm (p < 0.001, d = -2.76 - 2.66). Significant main effects for sex were found for logarithmic decrement Along Forearm (p < 0.001, d = 1.698) and Across Langer's Line (p = 0.021, d = 1.697).

CONCLUSIONS

Our results suggested that optimal incision line for this age group in males and females could potentially be performed diagonally i.e. Across Langer's Line or parallel i.e. Along Forearm to forearm axis. These directions would provide the lowest tension across a healing wound and possibly minimalize the risk of hypertrophic scarring post incision.

Characterizing the Mechanism of Action of Essential Oils on Skin Homeostasis—Data from Sonographic Imaging, Epidermal Water Dynamics, and Skin Biomechanics

Essential oils (EOs) have been recognized as materials of interest for dermatological applications, although some doubts remain regarding their safety and efficacy. We studied the action mechanisms of EOs from lavender and sage in human skin. Extracted EOs were incorporated (at 5% and 10%) in almond oil as a vehicle. Eleven healthy volunteers were selected and the prepared oils were tested on both forearms. All procedures respected the principles of good clinical practice. Effects were followed through high resolution sonography (HRS), epidermal water dynamics, and biomechanics. All variables were measured before and 30 min after application. Nonparametric statistical comparisons were applied (p < 0.05). HRS revealed a more echogenic epidermis, with a significant echogenicity decrease in the dermis (higher water retention) for all formulations. Significant TEWL decrease and an increase in superficial and deep epidermal hydration were also observed. These results indicate that EOs penetrate only into the most superficial layers of the skin, which is important for their safety profile. Furthermore, this “filmogenic” mechanism improving the epidermal water balance seems to connect directly with the observed biomechanical enhancement. These results confirm the clinical relevance of these compounds, in particular to restore the epidermal water content and prevent xerosis and other related disorders in sensitive (atopic, elderly) patients.

Changes in Skin Elasticity and Firmness Caused by Cosmetic Formulas Elaborated with Essential Oils of Aristeguietia glutinosa (matico) and Ocotea quixos (ishpingo). A Statistical Analysis

External factors such as prolonged exposure to solar radiation and environmental pollution accelerate the aging process of the skin, and this process is a challenge for pharmacological science. To counteract the effects of skin photoaging, the cosmetic industry has introduced natural topical products that have proved to be effective in reducing signs of age. In this sense, a statistical analysis was conducted on the changes in the properties of firmness and elasticity of the skin caused by cosmetic formulas (lotion and cream) elaborated with essential oils of Aristeguietia glutinosa (matico) and Ocotea quixos (ishpingo) in which the concentration of the oils in two cosmetic products (lotion and cream) varied to be tested in vivo, through the measurement of elasticity and firmness in three times T1 (0 day), T2 (28 days) and T3 (56 days), and in two age groups according to the Glogau scale (30 to 40 and 41 to 50 years). The results showed positive changes in the values of elasticity and firmness of the skin in the presentation of the lotion whose concentration was 20% Aristeguietia glutinosa (matico) and 80% Ocotea quixos (ishpingo), with a minimum application time of 28 days.

Non-invasive evaluation of elasticity of skin with the processing of ultrasound images during ultraviolet radiation: An animal photoaging model

OBJECTIVE

The aim of this study was to provide a non-invasive imaging method to evaluate the physical and mechanical parameters as a novelty method during skin photoaging.

METHODS

In order to evaluate the process of skin damage, 25 mice (C57BL6) were exposed to UVB radiation (0.03 mW/cm² ), 5 times a week for 5 weeks. The thickness of the epidermal and dermal layers was measured weekly from the ultrasound images (40 MHz). The elastic parameters of the skin were estimated from the processing of the sequential ultrasound images with the motion detection algorithm during the injury generation process.

RESULTS

The thickening, Young modulus, and shear modulus of the dermal and epidermal layers during the UVB damage process significantly increased during the 5-week study period (P < .05). In addition, the percentage of changes in the thickness of the epidermal layer (0.22 ± 0.01 mm in day 0 to 0.37 ± 0.02 mm in day 35) and dermal layer (0.57 ± 0.05 mm in day 0 to 0.90 ± 0.08 mm in day 35) increased by 68% and 57%, respectively. Furthermore, Young modulus (154.41 ± 8.8 kPa) was 11 times more than that of non-irradiated skin (14.90 ± 2.2 kPa) and the shear modulus (2.33 ± 0.04 kPa) was 2.2 times more than non-irradiated skin (1.06 ± 0.04 kPa).

CONCLUSION

With processing the sequential ultrasound images and extracting the thickening, the elasticity of the skin layers can detect skin lesions by UVB radiation.

Seasonal variations in the skin parameters of Caucasian women from Central Europe

BACKGROUND

The human skin is greatly affected by external factors such as UV radiation (UVR), ambient temperature (T), and air humidity. These factors oscillate during the year giving rise to the seasonal variations in the skin properties. The aim of this study was to evaluate the effect of seasons, environmental T, relative and absolute humidity on the skin parameters of Caucasian women, perform a literature review and discuss the possible factors lying behind the found changes.

MATERIALS AND METHODS

We measured stratum corneum (SC) hydration, transepidermal water loss (TEWL), sebum level, erythema index, and elasticity parameters R2 and R7 on the forehead and the cheek of Caucasian women from the Czech Republic throughout the year. We also performed a non-systematic literature review focused on the seasonal variations in these skin parameters.

RESULTS

We confirmed a well-documented low SC hydration and sebum production in winter. In spring, we found the lowest TEWL (on the forehead) and the highest SC hydration but also the highest erythema index and the lowest elasticity presumably indicating skin photodamage. For most of the skin parameters, the seasonal variations probably arise due to a complex action of different factors as we extensively discussed.

CONCLUSION

The data about the seasonal variations in the skin parameters are still highly inconsistent and further studies are needed for better understanding of the normal skin changes throughout the year.

Comparison of different MyotonPRO probes for skin stiffness evaluation in young women

BACKGROUND

Stiffness of skin is widely used parameter in many research areas, for example cosmetic industry, dermatology or rheumatology for assessing of skin condition as well as changes occurring in skin. In this pioneering study, we conducted measurements of skin stiffness using MyotonPRO -novel tool, which was mainly used to evaluate biomechanical properties of muscles, ligaments and tendons. We expected that MyotonPRO , which shows great reproducibility in previous studies, will also be able to measure skin stiffness.

MATERIALS AND METHODS

Four replaceable probes designed by MyotonPRO (L-shape short and medium arm, standard cylindrical flat-end probe and the same standard probe with disc attachment ) were tested for measurement of skin stiffness in young women (30 healthy females) at three different locations (clavicula, volar forearm and shin).

RESULTS

There was no significant difference between stiffness values obtained with L-shape short and L-shape medium arm probes in all investigated areas. Stiffness values recorded by regular probe and regular probe with disc attachment differ significantly from those collected with L-shape probes. There was also significant difference between values of stiffness obtained by standard with disc attachment and standard probes.

CONCLUSION

Both L-shape probes show a great reliability for skin stiffness assessment. Therefore, MyotonPRO can be considered a reliable device for assessing skin stiffness.