Cutaneous resonance running time varies with age, body site and gender in a normal Chinese population

Guided wave elastography of human skins with a layered model incorporating the effect of muscle state

In vivo mechanical characterization of skin finds broad applications in understanding skin aging, diagnosis of some skin diseases and assessing the effectiveness of diverse skin care strategies. Skin has a layered structure consisting of the epidermis, dermis and subcutaneous layers. Although much effort has been made towards mechanical characterization of skin, it remains a challenging issue to measure the mechanical properties of an individual layer in vivo. To address this issue, we here report a guided wave elastography method for layered human skin which incorporates the effect of muscle states. Both finite element simulations and phantom experiments have been performed to validate the method. For skin-mimicking phantoms with different fat layer thicknesses, the errors in the identified shear modulus of the skin layers are no more than 11 %. In vivo experiments have been carried out on 6 healthy subjects to demonstrate the potential use of the method in clinics. A statistical analysis indicates the muscle contraction contributes to the stiffening of the skin (p < 0.001). Finally, a phase diagram has been constructed to reveal the extent to which muscle sates (including both passive and active states) affect the measurement of elastic modulus of a skin layer, which may guide the application of the method in practice.

Split-face comparison of hydroquinone 4% plus nitrogen plasma vs. hydroquinone 4% alone in the treatment of melasma

Treatment of skin diseases is important yet challenging. One of the most common skin diseases in women is melasma, which features acquired facial hyperpigmentation. We studied the effect of cold atmospheric nitrogen plasma on this disease. To characterize the nitrogen plasma, we obtained the relative intensity of the species and the plasma temperature and skin temperature during processing at different input powers and gas flows. Patients complaining of melasma were treated with hydroquinone on both sides of the face, and one side was randomly selected for additional nitrogen plasma therapy. Eight treatment sessions of plasma processing were provided 1 week apart, and one follow-up session was scheduled 1 month after the end of treatment. The rate of improvement was scored by a dermatologist in the eighth session and 1 month following the last session using the modified Melasma Area Severity Index (mMASI). Skin biomechanical characteristics such as melanin, cutaneous resonance running time (CRRT), transepidermal water loss (TEWL), and hydration were measured at baseline and during the fourth, eighth, and follow-up sessions. On both sides, we observed a significant decrease in both CRRT and melanin (P < 0.05). TEWL did not change on both sides, while hydration decreased significantly only on the side to which hydroquinone was applied in isolation (P < 0.05). According to clinical scores, on both sides, we had significant improvement. On the side that plasma was not applied, the percentage reduction of pigmentation (mMASI) in the eighth and follow-up sessions in comparison with the baseline was 5.49 ± 8.50% and 33.04 ± 9.17%, respectively, while on the other side, these figures were 20.57 ± 6.64% and 48.11 ± 11%. For melanin, these figures were 13.84 ± 4.84% and 18.23 ± 7.10% on the hydroquinone side and 21.56 ± 3.13% and 23.93 ± 3.02% on the other side. According to these results, nitrogen plasma can safely complement topical hydroquinone to improve clinical outcomes when treating melasma without causing stratum corneum damage or skin discomfort, though confirmatory studies are needed.

Analysis of In Vivo Skin Anisotropy Using Elastic Wave Measurements and Bayesian Modelling

In vivo skin exhibits viscoelastic, hyper-elastic and non-linear characteristics. It is under a constant state of non-equibiaxial tension in its natural configuration and is reinforced with oriented collagen fibers, which gives rise to anisotropic behaviour. Understanding the complex mechanical behaviour of skin has relevance across many sectors including pharmaceuticals, cosmetics and surgery. However, there is a dearth of quality data characterizing the anisotropy of human skin in vivo. The data available in the literature is usually confined to limited population groups and/or limited angular resolution. Here, we used the speed of elastic waves travelling through the skin to obtain measurements from 78 volunteers ranging in age from 3 to 93 years old. Using a Bayesian framework allowed us to analyse the effect that age, gender and level of skin tension have on the skin anisotropy and stiffness. First, we propose a new measurement of anisotropy based on the eccentricity of angular data and conclude that it is a more robust measurement when compared to the classic "anisotropic ratio". Our analysis then concluded that in vivo skin anisotropy increases logarithmically with age, while the skin stiffness increases linearly along the direction of Langer Lines. We also concluded that the gender does not significantly affect the level of skin anisotropy, but it does affect the overall stiffness, with males having stiffer skin on average. Finally, we found that the level of skin tension significantly affects both the anisotropy and stiffness measurements employed here. This indicates that elastic wave measurements may have promising applications in the determination of in vivo skin tension. In contrast to earlier studies, these results represent a comprehensive assessment of the variation of skin anisotropy with age and gender using a sizeable dataset and robust modern statistical analysis. This data has implications for the planning of surgical procedures and questions the adoption of universal cosmetic surgery practices for very young or elderly patients.

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.

Evaluation of the efficacy and safety of plasma exeresis in periorbital rejuvenation using the Reviscometer®

BACKGROUND

Periorbital rejuvenation is performed through various methods. Recently, plasma exeresis has been suggested for the treatment of dermatochalasis and periorbital wrinkles.

AIMS

To evaluate the clinical efficacy and safety of plasma exeresis in periorbital rejuvenation and palpebral laxity and assess its effectiveness using the Reviscometer^® .

PATIENTS/METHODS

Fifty-six women with mild-to-severe dermatochalasis and periorbital wrinkles volunteered to participate in this clinical trial. They received plasma exeresis thrice at one-month intervals. The efficacy of the intervention was evaluated according to the Cutaneous Resonance Running Time (CRRT) value changes, photographic changes, patients' satisfaction, and clinical side effects.

RESULTS

This study showed significant clinical improvements in dermatochalasis and palpebral laxity after treatment compared with the baseline (p < 0.001). Most of the participants had relative satisfaction, and no significant or permanent side effects were observed.

CONCLUSION

The findings of this study suggest that plasma exeresis is a safe and effective nonsurgical method for periorbital rejuvenation. Furthermore, the procedure has no serious adverse effects if performed correctly and for the right patient.

Evaluation of the changes in sebum, moisturization and elasticity in acne vulgaris patients receiving systemic isotretinoin treatment

AIM

The aim of this study was to determine the change in facial skin sebum, hydration and elasticity of acne vulgaris patients after being treated with systemic isotretinoin.

METHOD

Patients who were diagnosed with acne vulgaris and who received systemic isotretinoin treatment for 6 months in Cerrahpaşa Medical Faculty Department of Dermatology between June 2012 and May 2017 were included in this study. The sebum, hydration and elasticity of the skin were measured non-invasively with a device called "Soft Plus Skin Analyses System" before treatment and 6 months after treatment. The relationship between the pre-treatment and post-treatment values were evaluated statistically. 35 adult patients (20 female, 15 male) who were diagnosed with acne vulgaris and who received systemic isotretinoin treatment for 6 months.

RESULTS

The pre-treatment sebum value for both sexes ranged between 5 and 100 and the mean value was calculated as 75.8 ± 28.0. The post-treatment sebum values ranged between 1 and 98 and the mean value was calculated as 48.4 ± 31.8. The difference between the pre-treatment and post-treatment values was statistically significant, p < 0.001. The decline in sebum value after treatment was 36%. The pre-treatment hydration values ranged between 9 and 77.5 and the mean was 34.6 ± 14.6. The post treatment hydration values ranged between 4.8 and 100 and the mean was calculated as 62.4 ± 28.6. The difference between the pre-treatment and post-treatment hydration values were statistically significant, p < 0.001. The post-treatment increase in hydration was 79%. The pre-treatment skin elasticity ranged between 28 and 50; the mean was 40.4 ± 5.5. The post-treatment elasticity values ranged between 20 and 50; and the mean was 37.5 ± 8.2. However, the difference was not statistically significant (p = 0.1).

CONCLUSION

With this study, it was concluded that, systemic isotretion leads to a 36% decline in skin sebum values and a 79% increase in the skin hydration. However, the change in skin elasticity was not statistically significant. Furthermore, the changes in sebum and skin hydration did not lead to a change in skin elasticity.

Efficacy and safety of non-thermal nitrogen plasma versus long-pulsed Nd:YAG laser for hand rejuvenation

This randomized controlled study aimed to investigate the efficacy and safety of multiple treatment sessions of pulsed non-thermal atmospheric pressure nitrogen plasma compared with long-pulsed Nd:YAG laser for hand rejuvenation. To optimize the nitrogen plasma mode for rejuvenation, the relative intensity of reactive species and skin temperature was compared at different input powers and time periods. Twenty-five patients with mild-moderate photodamaged skin were recruited; one hand was randomly selected for eight weekly treatment sessions with plasma (two passes), while the other was subjected to three monthly treatments with laser (until erythema became obvious). A blinded dermatologist scored the mean wrinkle and dyschromia improvement at 1 and 2 months after the first treatment and 1 and 3 months after the last treatment. The patients' satisfaction and the biomechanical characteristics of the skin including cutaneous resonance running time (CRRT), melanin, transepidermal water loss (TEWL), and hydration were evaluated. Clinically, both methods gave rise to a similar, significant improvement in wrinkles (49.09 ± 19.18% and 39.32 ± 18.21% after plasma and laser, respectively) and dyschromia (45.00 ± 26.32% and 30.62% ± 24.99% after plasma and laser, respectively) (P < 0.05). A significant decrease in CRRT and melanin was seen following treatment with either method (P < 0.05). Notably, plasma therapy led to a significant decrease in TEWL and boosted skin hydration. This is while laser therapy augmented the TEWL and reduced skin hydration. Our findings corroborate that cold plasma is as effective and safe as long-pulsed Nd:YAG laser, with less discomfort and dryness during treatment. The protocol was approved by the Iranian Registry of Clinical Trials. IRCT20160320027109N4. Registered 9 April 2019 (This manuscript is only a part of this registered project.).

Efficacy of microneedling versus fractional Er:YAG laser in facial rejuvenation

BACKGROUND

Microneedling and fractional lasers have been used in facial rejuvenation with acceptable results and low adverse effects.

AIMS

To compare the efficacy of microneedling with fractional Er:YAG in facial skin rejuvenation.

PATIENTS/METHODS

This study was planned as a split-face clinical trial. Volunteers were randomly allocated to receive three monthly treatments on each side of the face, one with fractional Er:YAG laser and one with microneedling. The assessments included investigating clinical outcomes by two blinded dermatologists accompanied by measuring skin biophysical characteristics including cutaneous resonance running time (CRRT) and transepidermal water loss (TEWL). Moreover, possible adverse effects, downtime, and patients' satisfaction were recorded at baseline, 1 month after each treatment, and 3 months after the last treatment session. The protocol was approved by the Iranian Registry of Clinical Trials (IRCT20160820029436N3).

RESULTS

Of the 32 selected volunteers, 24 subjects completed the study. The clinical assessment showed a significant improvement of the face appearance along with a significant reduction in dyschromia, and periorbital wrinkling (P-value < .05), with both procedures without any considerable difference between two methods. Moreover, the patients showed substantial satisfaction with both modalities with no statistically significant difference. Mean TEWL and CRRT values also decreased significantly in both groups with no considerable difference. The downtime was significantly shorter in the microneedling-treated side. There were no long-lasting or severe adverse effects after treatment with both methods.

CONCLUSION

Microneedling and fractional Er:YAG laser have comparable efficacy in facial rejuvenation, but little downtime of the former makes it preferable for many patients.

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

Biomechanics of the skin is an important subject in skin research. It has been studied for many decades involving various technologies and methods to characterize and quantify mechanical properties of the skin under different in vivo conditions. The present EEMCO paper reviews the current rel-evant information, providing practical orientation to researchers dedicated to in vivo assessment of biomechanics of skin and its annexes. We discuss the available non-invasive instruments, including their principles and variables. A correspondence between the descriptors nomenclature proposed by Agache and the designation for the suction-based standard instruments is proposed. The addressed properties include skin softness/stiffness, firmness, elasticity, elastic and viscoelastic properties, extensibility, resilience, anisotropy, acoustical shock wave hardness, friction (in relation to topographic properties), thickness, fiber/stress mechanics (bending, cyclic, tensile, fatigue, or torsion), and hardness. We provide the relation of these properties to biomechanical descriptors and in some cases to SI units. Practical guidance for the proper use of these instruments, limitations, and possible interpretations are provided, while discussing the meaning of descriptive or "phenomenological" variables. For studies intended to quantify the effect of an intervention with regard to mechanical properties, we recommend a minimum of 30-40 participants, based on normal distribution of the data sets. Some important limitations are recognized, including the lack of standardization of procedures and calibration of instruments, which compromises the relevance and real nature of the descriptors/parameters obtained with these devices. The present work highlights an approach to a better practice and a science-supported biomechanical assessment of human skin, hair, and nails.

Ageing profiles of Caucasian and Chinese cohorts - focus on hands skin

OBJECTIVE

In spite of hand care being a dynamic segment of skin care, hands skin physiology has been receiving little attention in comparison to facial skin. In the present study, we aimed at gathering a comprehensive set of skin data from the dorsal part of the hand to study age related-changes in two ethnic groups (Caucasian and Chinese).

METHODS

Skin topographic, skin colour/colour heterogeneities, skin chromophores and skin biophysical measurements of 116 Caucasian and Chinese female volunteers aged 30-65 years old were collected in Ireland and in China as part of a cross-sectional study.

RESULTS

Topographic alterations happened at both micro and macro scales with a noticeable delay in the onset of 10 years for the Chinese cohort. Similar evolution of skin colour with ageing was observed between the two cohorts and strong dissimilarities were seen when it came to colour heterogeneities and melanin hyper concentration, with a 20-year delay in severity for the Chinese cohort. A similar sharp drop of skin hydration occurred when reaching the 60's regardless of the group and substantial differences were recorded for skin biomechanical properties of the skin.

CONCLUSION

These results provide additional insights about hand skin physiology in relation to ageing and ethnic differences, especially when put into perspective with what is currently known about facial ageing. This research yield additional material for hand cream product rationale and strategies for mitigating the appearance of ageing hands.

Efficacy and safety of long pulse Nd:YAG laser versus fractional erbium:YAG laser in the treatment of facial skin wrinkles

Fractional lasers such erbium:YAG (Er:YAG) are among popular options for facial rejuvenation. Lasers with infrared wavelength ranges such as long pulse Nd:YAG have been used in nonablative rejuvenation of skin with variable outcomes. In this study, we plan to compare safety and efficacy of fractional Er:YAG and long pulse Nd:YAG for facial rejuvenation applying objective and subjective measurements. Twenty-five patients with Glogau photo aging scale of II to IV were recruited in this randomized face-split double-blind controlled trial. Individuals received three monthly treatments on two sides of the face; one side was treated by fractional Er:YAG laser and the other side by long pulse Nd:YAG laser. Outcomes were evaluated by two blinded dermatologists, patient satisfaction reports and objective measurements of cutaneous resonance running time (CRRT). Both modalities significantly improved periorbital wrinkling, nasolabial folds, dyschromia and skin laxity, and sagging of jowls (p value < 0.05), with no noticeable difference between two lasers. Mean CRRT values decreased significantly after treatment with both lasers. The downtime was significantly lower for the Nd:YAG-treated side. Fractional Er:YAG laser and long pulse Nd:YAG has comparable effects in facial rejuvenation but little to no downtime of the latter makes it popular for many patients. ClinicalTrials.gov Identifier: IRCT2015120320468N3.

Autologous Fat Grafting in the Treatment of Facial Scleroderma

Systemic sclerosis (SSc) is a rare systemic autoimmune disease, characterized by progressive cutaneous and internal organ fibrosis. Orofacial manifestations of systemic sclerosis are extremely disabling and treatment options are limited. In this study, we aimed to assess the safety and efficacy of autologous fat grafting in the face of patients with systemic sclerosis. We enrolled 16 SSc patients suffering from facial sclerosis and limited mouth opening capacity. Autologous fat injection ranging from 15 to 40 ml was administered per patient, based on their face morphology. The patients were evaluated at baseline and 3 months after fat injection. Evaluations included mouth opening capacity, mouth handicap in systemic sclerosis (MHISS), Rodnan skin sclerosis score, skin biophysical properties using a sensitive biometrologic device with the assessment of cutaneous resonance running time (CRRT), volumizing and aesthetic effects based on pre- and posttreatment photographs, possible side effects, and global patient satisfaction. Clinical assessment showed autologous fat transfer significantly improved mouth opening capacity and the MHISS and Rodnan score of patients with facial scleroderma (p value <.001). The aesthetic and/or functional results of fat injection were satisfying to about 80% of the patients. The changes in CRRT values were not significant. Our findings support the possible therapeutic role of autologous fat grafting in improving facial scleroderma both in aesthetic and in functional aspects. This trial is registered with IRCT20180209038677N1.

Male versus female skin: What dermatologists and cosmeticians should know

Introduction

The skin is important for the perception of health and beauty. Knowledge of the physiological, chemical, and biophysical differences between the skin of male and female patients helps dermatologists develop a proper approach not only for the management of skin diseases but also to properly take care of cosmetic issues. The influence of genetic and environmental factors on skin characteristics is also critical to consider.

Methods

A literature search of PubMed and Google was conducted to compare the biophysical and biomechanical properties of the skin of male and female patients using the keywords "skin", "hydration", "water loss", "sebum", "circulation", "color", "thickness", "elasticity", "pH", "friction", "wrinkle", "sex", "male", and "female".

Results

A total of 1070 titles were found. After removing duplications and non-English papers, the number was reduced to 632. Of the 632 titles, 57 were deemed suitable for inclusion in this review. The studies show that the skin parameters of hydration, transepidermal water loss, sebum, microcirculation, pigmentation, and thickness are generally higher in men but skin pH is higher in women.

Conclusions

These parameters can be considered as age markers in some cases and are susceptible to change according to environment and life style. Biometrological studies of the skin provide useful information in the selection of active principles and other ingredients of formulations to develop a specific approach for cosmetic treatments.

Efficacy of long pulse Nd:YAG laser versus fractional Er:YAG laser in the treatment of hand wrinkles

There are different modalities for hand rejuvenation. Fractional Er:YAG laser and long pulse Nd:YAG laser were introduced for treating hand wrinkles. We plan to compare fractional Er:YAG laser and long pulse Nd:YAG laser in a randomized controlled double-blind design with multiple sessions and larger sample size in comparison with previous studies. Thirty-three participants with hand wrinkles entered this study. They were randomly allocated to undergo three monthly laser treatments on each hand, one with a fractional Er:YAG laser and the other with a long pulse Nd:YAG laser. The evaluations included assessment of clinical improvement determined by two independent dermatologists not enrolled in the treatment along with measuring skin biomechanical property of hands using a sensitive biometrologic device with the assessment of cutaneous resonance running time (CRRT). Moreover, potential side effects and patients' satisfaction have been documented at baseline, 1 month after each treatment, and 3 months after the final treatment session. Clinical evaluation revealed both modalities significantly reduce hand wrinkles (p value < 0.05), with no significant difference between two lasers. Mean CRRT values also decreased significantly after the laser treatment compared to those of the baseline in both laser groups. There was no serious persistent side effect after both laser treatments. Both fractional Er:YAG and long pulse Nd:YAG lasers show substantial clinical improvement of hand skin wrinkles with no serious side effects. However, combination treatment by these lasers along with the other modalities such as fat transfer could lead to better outcomes in hand rejuvenation.

TRIAL REGISTRATION

IRCT2016032020468N4.

Quantitative Assessment of Skin Stiffness in Localized Scleroderma Using Ultrasound Shear-Wave Elastography

The purpose of this study was to evaluate the usefulness of ultrasound shear-wave elastography (US-SWE) in characterization of localized scleroderma (LS), as well as in the disease staging. A total of 21 patients with 37 LS lesions were enrolled in this study. The pathologic stage (edema, sclerosis or atrophy) of the lesions was characterized by pathologic examination. The skin elastic modulus (E-values including E_mean, E_min, E_max and E_sd) and thickness (h) was evaluated both in LS lesions and site-matched unaffected skin (normal controls) using US-SWE. The relative difference of E-values (E_RD) was calculated between each pair of lesions and its normal control for comparison among different pathologic stages. Of the 37 LS lesions, 2 were in edema, 22 were in sclerosis and 13 were in atrophy. US-SWE results showed a significant increase of skin elastic modulus and thickness in all lesions (p < 0.001 in sclerosis and p < 0.05 in atrophy) compared with the normal controls. The measured skin elastic modulus and thickness were greater in sclerosis than in atrophy. However, once normalized by skin thickness, the atrophic lesions, which were on average thinner, appeared significantly stiffer than those of the sclerosis (normalized E_RD: an increase of 316.3% in atrophy vs. 50.6% in sclerosis compared with the controls, p = 0.007). These findings suggest that US-SWE allows for quantitative evaluation of the skin stiffness of LS lesions in different stages; however, the E-values directly provided by the US-SWE system alone do not distinguish between the stages, and the normalization by skin thickness is necessary. This non-invasive, real-time imaging technique is an ideal tool for assessing and monitoring LS disease severity and progression.

Excessive Weight Favours Skin Physiology - Up to a Point: Another Expression of the Obesity Paradox

BACKGROUND/AIMS

Recently classified as an epidemic by the WHO, obesity (as well as the state of being overweight) clearly affects significant populations across all ages. The relationship between obesity and some diseases (e.g. cardiovascular ones) is known, although many paradoxes remain to be explained. Very little information is available, however, regarding its impact on skin physiology and skin disease. This study aims to examine the influence of excessive weight on epidermal hydration and transepidermal water loss, key variables of skin water balance and skin biomechanics.

METHODS

A convenience sample of 89 healthy female volunteers was selected and divided into 4 groups, according to their BMI (body mass index), as normal (control), overweight, obese (I and II), and morbid. Skin physiology was quantitatively assessed in all individuals in 4 anatomical areas using non-invasive biometrical analysis by reference instrumentation. Descriptive and comparative statistics were applied, adopting a confidence level of 95%.

RESULTS

A non-linear alteration for all variables was detected as a function of BMI.

CONCLUSION

Results suggest that excessive weight might favour skin performance within certain limits, reflecting a particular adaptation of the skin to the weight gain and body contour.

About the in vivo quantitation of skin anisotropy

BACKGROUND/PURPOSE

Human skin anisotropy is difficult to quantify. The Cutiscan^® , is allegedly, the first biometrical system to provide information on the elastic and viscoelastic properties, as well as on anisotropy and directionality of the human skin in vivo. Thus, this study aims to contribute to characterize this new device and its applicability, and to compare its behavior with two other well-known devices-the Cutometer^® and the Reviscometer^® .

METHODS

Measurements were conducted with each device in three different anatomical sites (forehead, forearm and leg) of 20 female volunteers engaged after informed consent. The participants in the study were aged 19-73 years (mean age 37 ± 18.7 years old), and were divided in two groups (n = 10), based on their age - Group I, mean age 22 ± 1.3 years; Group II, mean age 52 ± 13.7 years.

RESULTS

All devices were useful tools to explore the anatomical and the age dependant changes in biomechanical terms, showing different discriminative capacities. Interesting correlations were established between the variables provided by the equipment.

CONCLUSION

The Cutiscan^® descriptors delivered excellent relationships with those from Cutometer^® and Reviscometer^® , while providing more detailed information about skin anisotropy through a full 360° analysis.

Efficacy and safety of fractional CO2 laser versus fractional Er:YAG laser in the treatment of facial skin wrinkles

Ablative fractional lasers were introduced for treating facial rhytides. Few studies have compared fractional CO₂ and Er:YAG lasers on cutaneous photodamages by a split trial. The aim of the present study was to compare these modalities in a randomized controlled double-blind split-face design with multiple sessions and larger sample size compared to previous studies done before. Forty patients with facial wrinkles were enrolled. Patients were randomly assigned to receive three monthly treatments on each side of the face, one with a fractional CO₂ and one with a fractional Er:YAG laser. The evaluations included investigating clinical outcome determined by two independent dermatologists not enrolled in the treatment along with measuring skin biomechanical property of cheeks using a sensitive biometrologic device with the assessment of cutaneous resonance running time (CRRT). Moreover, possible side effects and patients' satisfaction have been recorded at baseline, 1 month after each treatment, and 3 months after the last treatment session. Clinical assessment showed both modalities significantly reduce facial wrinkles (p value < 0.05), with no appreciable difference between two lasers. Mean CRRT values also decreased significantly after the laser treatment compared to the baseline in both laser groups. There was no serious long-standing adverse effect after both laser treatments, but the discomfort was more pronounced by the participants after CO₂ laser treatment. According to the present study, both fractional CO₂ and fractional Er:YAG lasers show considerable clinical improvement of facial skin wrinkles with no serious adverse effects, but post-treatment discomfort seems to be lower with Er:YAG laser.

Skin Biophysical Characteristics in Patients with Keratoconus: A Controlled Study

Background. Keratoconus is a relatively common corneal disease causing significant visual disability. Individuals with connective tissue disorders that affect the skin such as Marfan's syndrome and Ehlers-Danlos syndrome or patients with atopic dermatitis show an increased prevalence of keratoconus. It seems that there are some concurrent alterations of skin and cornea in patients with keratoconus. Objective. We plan to compare skin biophysical characteristics in patients with keratoconus and healthy controls. Methods. Forty patients with keratoconus (18 females and 22 males) with mean (SD) age of 33.32 (9.55) years (range 19-56) and 40 healthy controls were recruited to this study. Skin biophysical characteristics including cutaneous resonance running time (CRRT), stratum corneum hydration, and melanin values were measured in patients and controls. Results. The median CRRT, stratum corneum hydration, and melanin measurements were significantly lower in patients with keratoconus in comparison with healthy controls. Conclusion. There are some alterations of skin biophysical properties in patients with keratoconus. Therefore, the assessment of these skin parameters could provide us some clues to the possible common biophysical variations of cornea and skin tissue in diseases such as keratoconus.

Evaluation of Subcision for the Correction of the Prominent Nasolabial Folds

Background. A prominent nasolabial fold (NLF) is a cosmetic problem. Currently, numerous therapeutic modalities are available for pronounced NLFs with variable efficacy. Objective. To determine the efficacy and safety of subcision using a hypodermic needle for the correction of the prominent NLFs and its effect on skin elasticity. Methods. Sixteen patients with prominent NLFs underwent subcision. The investigators' assessment of improvement and the patients' satisfaction were both recorded 1 and 6 months after the procedure. Also, we evaluate the skin elasticity of NLFs before and after the treatment using a sensitive biometrologic device with the measurement of cutaneous resonance running time (CRRT). Results. Thirteen (81.25%) patients showed a moderate improvement at 1st month and 13 (81.25%) patients had at least a mild improvement at 6th month. There was no persistent side effect lasting more than a few days. Mean CRRT at 1 and 6 months after the treatment was significantly higher compared to the baseline. Conclusion. Subcision may be considered effective for the correction of pronounced NLFs. However, further controlled studies with larger sample size are necessary to assess the efficacy of this technique in particular with use of more objective assessment of skin biometric characteristics. This trial is registered with IRCT201108097270N1 (registered on January 27, 2012).

Cutaneous resonance running time is decreased in psoriatic lesions

BACKGROUND/AIMS

Psoriasis is characterized by lower stratum corneum (SC) hydration and dermal inflammation. Both SC hydration and cutaneous inflammation influence cutaneous resonance running time (CRRT). However, the characteristics of CRRT in psoriatic lesions are largely unknown. In the present study, we assessed whether changes in CRRT occur in psoriatic lesions in Chinese.

METHODS

A Reviscometer RVM600 and Corneometer CM 825 were used to measure CRRTs and SC hydration, respectively, in psoriatic lesions (psoriasis vulgaris) on the extensor of forearm in 111 subjects (58 men, 53 women), aged 23-80 years (50.42 ± 1.23 years). The contralateral uninvolved sites served as control.

RESULTS

In comparison with contralateral uninvolved sites, CRRTs in psoriatic lesions were reduced significantly in all directions. There was neither gender nor age difference in the extent of reduction in CRRTs. However, the reduction of CRRTs varied with measurement directions. Positive correlations of SC hydration with CRRTs were found at some directions in uninvolved and involved sites in young men whereas CRRTs in psoriatic lesions were not correlated with SC hydration in either aged or young women. Moreover, CRRT at 0-6 o'clock direction was positively correlated with SC hydration in involved sites of aged men.

CONCLUSION

Cutaneous resonance running times are decreased in psoriatic lesions. Reduction of CRRTs varies with measurement directions, but not gender or age. Measurement of CRRTs could be another valuable approach to assess the severity of psoriasis and the efficacy of its treatment.

Characterization of skin friction coefficient, and relationship to stratum corneum hydration in a normal Chinese population

BACKGROUND AND OBJECTIVES

Studies have demonstrated that some cutaneous biophysical properties vary with age, gender and body sites. However, the characteristics of the skin friction coefficient in different genders and age groups have not yet been well established. In the present study, we assess the skin friction coefficient in a larger Chinese population.

METHODS

A total of 633 subjects (300 males and 333 females) aged 0.15-79 years were enrolled. A Frictiometer FR 770 and Corneometer CM 825 (C&K MPA 5) were used to measure the skin friction coefficient and stratum corneum hydration, respectively, on the dorsal surface of the hand, the forehead and the canthus.

RESULTS

In the females, the maximum skin friction coefficients on both the canthus and the dorsal hand skin were observed around the age of 40 years. In the males, the skin friction coefficient on the dorsal hand skin gradually increased from 0 to 40 years of age, and changed little afterward. Skin friction coefficients on some body sites were higher in females than in age-matched males in some age groups. On the canthus and the dorsal hand skin of females, a positive correlation was found between skin friction coefficient and stratum corneum hydration (p < 0.001 and p < 0.0001, respectively). In contrast, in males, the skin friction coefficient was positively correlated with stratum corneum hydration on the forehead and the dorsal hand skin (p < 0.05 and p < 0.0001, respectively).

CONCLUSION

The skin friction coefficient varies with age, gender and body site, and positively correlates with stratum corneum hydration on some body sites.