Liliana Tavares

Positive impact of dietary water on in vivo epidermal water physiology

The importance of water in human physiology is well known, also for skin functionality. This study was conducted to assess the effects of dietary water on epidermal skin hydration in healthy females.

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.

Assessing the impact of the regular use (4 weeks) of an alcohol-based hand sanitizer on TEWL and epidermal hydration: Avaliação do impacto do uso regular (4 semanas) de um gel desinfetante na PTEA e hidratação epidérmica

The Stratum corneum is a principal protector against physical, chemical, biological aggression and water loss in human skin. The repeated use of alcohol-based hand sanitizers might result in dryness and aggression. This study aims to evaluate the impact of a four week-long regular use of an alcohol-based gel hand sanitizer on skin hydration on the epidermal ‘barrier’ function using a kinetic model to quantify TEWL desorption curves following a POST test. A group of 13 female (19.7 ± 1.0 years old) washed one of their hands for 29 consecutive days with a commercially available ethanol-based gel sanitizer. TEWL, superficial hydration (SH) and deep hydration (DH) were measured on days 1, 8, 15, 22 and 29, while a continuous TEWL recording following a 24 hour POST was made on days 1, 15 and 29 on a second skin area. No differences were found for the control hand throughout the study. For the test hand an increase of TEWL was found between days 1 and 8, as well as an increase of SH and DH between days 1 and 22. No significant differences were found for the kinetic parameters. These results suggest that the frequent use of the sanitizer gel might alter the skin barrier function.

Impact of excess body weight on skin hydration and biomechanics

© Springer International Publishing Switzerland 2015. P. Humbert et al. (eds.), Measuring the Skin

Dietary water seems to improve skin hydration without influencing hemodynamics: A água da dieta parece favorecer a hidratação cutânea sem afectar a hemodinâmica

The various studies on the importance of water in the hydration of human skin have suggested that an increased dietary intake might positively impact the physiology of normal skin. We evaluated the consequences of increasing water intake through drinking in skin hydration in vivo. Eating habits were maintained, evaluated by a Food Frequency Questionnaire and based on total water consumption. In two groups with different total water consumption, we evaluated the impact of 2L/day water after 30 days,. This increase produced no hemodynamic changes or weight changes but an improvement in the epidermal hydration was suggested. The magnitude of the impact on skin hydration was higher in the group that regularly consumed less water, suggesting that the increase in water consumption has more beneficial effects on those individuals who habitually consume less water per day. These data are consistent with the published literature, justifying interest in looking further into this topic, in order to better understand the importance of dietary water in the context of cutaneous physiology, especially in the group of subjects with reduced consumption habits.

Impact of overweight on the normal physiology of human in vivo skin: Impacto do excesso de peso sobre a fisiologia normal da pele humana in vivo

Obesity is an increasing public health issue, particularly in Portugal, where more than 50% of the population is obese. The pathophysiological consequences of being overweight have a severe cutaneous impact. However, there is still a lack of studies to link these alterations to BMI categories. This present work intends to identify the hydration and biomechanical behaviour changes related to weight augmentation. This transversal study was performed on a convenience sample of 57 volunteers, all females, aged between 20 and 46 (30±8) years old. Volunteers were divided in two groups – group I, with a BMI between 19,9 and 24,9 Kg/m2 and group II, between 25 and 29,9 Kg/m2. One single determination of the superficial hydration, transepidermal water loss and biomechanical behaviour of the skin, was obtained with non-invasive methods. The data showed that weight increase positively influences hydration levels and transepidermal water loss, and negatively influences the skins biomechanical behaviour. Despite the relevance of these results, there is still a need for complementary studies, with a wider number of individuals, in order to better understand its nature and meaning.

Exploring in vivo models to characterize peripheral microcirculation – a pilot study: Explorando modelos in vivo para caracterizar a microcirculação periférica - um estudo piloto

In recent years cutaneous circulation has emerged as an interesting window through which to study microcirculatory function and dysfunction mechanisms. Non-invasive technologies, including Laser Doppler Flowmetry (LDF), transcutaneous gasimetry and Transepidermal Water Loss (TEWL), helped to consider cutaneous circulation as a useful translational model in vascular disease. In this study we attempted to evaluate the response profile from a group of healthy young individuals (n=8), of both genders (24,5 ± 0,8 years old) to three perfusion-conditioning maneuvers in the lower limb A: leg elevation while seated; B: leg elevation during dorsal decubitus; C: supra-systolic occlusion with a tourniquet-cuff. Measurement techniques included LDF, transcutaneous (tc) pO2 and pCO2 partial pressures, by gasimetry and TEWL by evaporimetry. Descriptive and nonparametric statistics were applied and a 95% confidence level adopted. tcpO2 and tcpCO2 changed significantly during the maneuvers. A reciprocal evolution profile was registered in LDF and TEWL in A and C which might suggest that under the present experimental conditions local perfusion might influence the epidermal “barrier” function. The proposed models seem to be appropriate to characterize the peripheral microcirculation in vivo, justifying further development studies.