Correlations between transepidermal water loss rates and stratum corneum hydration levels in healthy children / 中华皮肤科杂志

Objective:To determine whether the transepidermal water loss rate (TEWL) is correlated with the stratum corneum (SC) hydration level.Methods:Healthy children aged ≤ 17 years were enrolled from Medical Center for Public Health of Puning, 2 kindergartens and 2 primary schools, from October 2021 to June 2022. TEWL and SC hydration levels were measured on the left forearm and right anterior shank using a device for measuring skin physiological funcitons. Pearson correlation analysis was used to determine the correlations between TEWL and SC hydration levels in children of different ages and genders.Results:A total of 1 396 healthy children were enrolled, aged from 1 month to 17 years. Among them, 783 were male children and 613 were female children. In children aged 1 to < 12 months, no correlation was observed between TEWL and SC hydration levels on the forearms of male children, while TEWL was positively correlated with SC hydration levels on the anterior shanks of male children, as well as on the forearm and anterior shanks of female children ( r = 0.283, 0.404, 0.420, respectively, all P < 0.05) . In children aged 1 to 2 years, positive correlations were observed between the above two indicators on the anterior shanks of male children and forearms of female children ( r = 0.370, 0.419, respectively, both P < 0.01) , while there were no correlations between the two indicators on the anterior shanks of female children or forearms of male children. Positive correlations were observed between TEWL and SC hydration levels on both the forearms and anterior shanks of female children and the forearms of male children aged 3 to 5 years and 6 to 11 years ( r values ranging from 0.172 to 0.293, all P < 0.05) , but not on the anterior shanks of male children aged from 6 to 11 years. The group aged 12 to 17 years exhibited significantly positive correlations between TEWL and SC hydration levels on both the anterior shanks and forearms of male and female children ( r values ranging from 0.269 to 0.485, all P < 0.001) . Conclusion:SC hydration levels are positively correlated with TEWL on the anterior shanks and forearms of healthy children, and the degree of correlation tends to increase with age.

Quantificação de substâncias do fator de hidratação natural (NMF) do estrato córneo ex vivo em função do fototipo e idade / Ex vivo quantification of natural hydration factor (NMF) substances in the stratum corneum as a function of phototype and age

A hidratação cutânea ocorre, em parte, pelos componentes do Fator de Hidratação Natural (NMF), originados da degradação da filagrina, sendo alguns exemplos o ácido pirrolidona-carboxílico (PCA), o ácido urocânico (UCA) e a histidina (His). Estes estão presentes no estrato córneo (EC). O objetivo deste projeto de pesquisa foi determinar, por cromatografia líquida de alta eficiência (CLAE), o PCA, o UCA e a His no estrato córneo de participantes obtido por tape stripping em função do fototipo e idade do participante da pesquisa. Participantes foram selecionados em função da idade acima de 18 anos, ambos os gêneros e fototipo da pele entre I a VI, de acordo com a classificação de Fitzpatrick. As amostras do EC foram obtidas do antebraço volar por tape stripping e irradiadas artificialmente. A cromatografia líquida de alta eficiência (CLAE) foi eficaz para separação e quantificação adequada das substâncias químicas His, PCA e os isômeros de UCA (trans-UCA e cis-UCA) no estrato córneo dos participantes. O método apresentou-se seletivo e ausente de interferentes, ademais, possuiu linearidade e limites de detecção e quantificação compatíveis com os objetivos dessa investigação. No fototipo I, os níveis de His foram menores em comparação aos demais grupos. Ademais, os níveis dessa mesma substância não apresentaram diferença entre as faixas etárias. Em função da irradiação das amostras, o montante de His aumentou em todos os fototipos. Os níveis de PCA apresentaram-se menores após a irradiação em todos os fototipos de pele. Ainda, as concentrações do PCA foram mais elevadas na faixa etária de 46 a 55 anos de idade. Os níveis de concentração do isômero cis-UCA foram maiores nos participantes com fototipo III, após a irradiação UV. Os níveis de concentração do isômero trans-UCA diminuíram após a irradiação, de forma proporcional à formação de cis-UCA em todos os fototipos. A faixa etária de 46-55 anos de idade obteve níveis significativamente menores de trans-UCA e cis-UCA

Cutaneous hydration occurs, in part, by the components of the Natural Hydration Factor (MFN), originating from the degradation of filagrina, some examples being pyrrolidone-carboxylic acid (PCA), urocanic acid (UCA) and histidine (His). These are present in the stratum corneum (SC). The objective of this research project was to determine, by high efficiency liquid chromatography (HPLC), the PCA, UCA and His in the stratum corneum of participants obtained by tape stripping due to the phototype and age of the research participant. Participants were selected according to age above 18 years, both genders and skin phototype between I and VI, according to Fitzpatrick's classification. The SC samples were obtained from the volar forearm by tape stripping and artificially irradiated. High efficiency liquid chromatography (HPLC) was effective for the separation and proper quantification of the chemicals His, PCA and UCA isomers (trans-UCA and cis-UCA) in the stratum corneum of the participants. The method was selective and absent from interfering, in addition, it had linearity and limits of detection and quantification compatible with the objectives of this investigation. In phototype I, His levels were lower compared to the other groups. Moreover, the levels of this same substance showed no difference between age groups. Due to the irradiation of the samples, the amount of His increased in all phototypes. PCA levels were lower after irradiation in all skin phototypes. Furthermore, PCA concentrations were higher in the age group from 46 to 55 years of age. The concentration levels of the cis-UCA isomer were higher in participants with phototype III after UV irradiation. The concentration levels of the trans-UCA isomer decreased after irradiation, proportionally to the formation of cis-UCA in all phototypes. The age group 46-55 years of age obtained significantly lower levels of trans-UCA and cis-UCA

Mupirocin ointments: In vitro x In vivo bioequivalence evaluation

Abstract Bioequivalence (BE) assessment of topical drug products is a long-standing challenge. Agencies such as the Food and Drug Administration (FDA) and the European Medicines Agency (EMA) have published several drafts in recent years suggesting different approaches as alternative to evaluate the BE. A proposed Topical Classification System (TCS) has even been discussed. Given the above, the objective of this research was to use in vitro and in vivo BE approaches to evaluate Brazilian marketed mupirocin (MPC) ointments, previously classified as TCS class The in vitro permeation test (IVPT) was performed by applying formulations to pig skin by Franz cells. The in vivo methodology was dermatopharmacokinetic (DPK). These approaches (in vivo tape stripping and IVPT) demonstrated capability of distinguishing among different formulations, thus making them useful methodologies for BE evaluation.

Does dry skin indicate defective epidermal permeability barrier? / 中华皮肤科杂志

It has been speculated that dry skin results from dysfunction of epidermal permeability barrier. But so far, there is no sufficient evidence to support this speculation. In fact, dry skin indicates low levels of stratum corneum hydration. Stratum corneum hydration levels are primarily determined by the content of natural moisturizers in the skin, while epidermal permeability barrier is mainly regulated by intercellular lipids and structural proteins in the stratum corneum. If dry skin is due to a defective permeability barrier, stratum corneum hydration levels should be inversely correlated with transepidermal water loss (TEWL) , an indicator of epidermal permeability barrier function. But no negative correlation has been demonstrated between stratum corneum hydration levels and TEWL in either normal human skin, ichthyoses lesions of patients, or sebaceous gland-deficient mice in a number of studies. In contrast, a positive correlation between stratum corneum hydration levels and TEWL was observed in normal human skin. Taken together, a line of evidence suggests that dry skin unlikely indicates epidermal permeability barrier dysfunction.

Enhancing effect and mechanism of muscone on transdermal penetration of traditional Chinese medicine ingredients with different log P value / 中国中药杂志

This study aimed to investigate the enhancing effect of muscone on the transdermal penetration of traditional Chinese medicine ingredients and explore its possible mechanism of action. The Franz diffusion cells were employed to investigate the effect of muscone on the transdermal permeation of a series of model drugs with a wide range of log P values. The solubilities at saturation and the stratum corneum(SC)/vehicle partition coefficients of model drugs were measured to evaluate the effect of muscone on drug thermodynamic activities and partition of drugs into SC. Attenuated total reflectance-Fourier transform infrared spectroscopy(ATR-FTIR) was employed to explore the effect of muscone on the molecular structure of SC. The results showed that muscone significantly promoted the transdermal penetration of hydrophilic and lipophilic drugs, and the enhancement ratio(ER) increased with the decrease in the log P. Muscone could interact with the SC lipids to increase the disorder and fluidity of lipid bilayer packing, which improved skin permeability and promoted transdermal absorption of drugs. This study provides a scientific basis for the application of muscone in traditional Chinese medicine topical preparations.

Mechanistic insights of the controlled release capacity of polar functional group in transdermal drug delivery system: the relationship of hydrogen bonding strength and controlled release capacity

Background@#Hydrogen bonding interaction was considered to play a critical role in controlling drug release from transdermal patch. However, the quantitative evaluation of hydrogen bonding strength between drug and polar functional group was rarely reported, and the relationship between hydrogen bonding strength and controlled release capacity of pressure sensitive adhesive (PSA) was not well understood. The present study shed light on this relationship.@*Methods@#Acrylate PSAs with amide group were synthesized by a free radical-initiated solution polymerization. Six drugs, , etodolac, ketoprofen, gemfibrozil, zolmitriptan, propranolol and lidocaine, were selected as model drugs. drug release and skin permeation experiments and pharmacokinetic experiment were performed. Partial correlation analysis, fourier-transform infrared spectroscopy and molecular simulation were conducted to provide molecular details of drug-PSA interactions. Mechanical test, rheology study, and modulated differential scanning calorimetry study were performed to scrutinize the free volume and molecular mobility of PSAs.@*Results@#Release rate of all six drugs from amide PSAs decreased with the increase of amide group concentrations; however, only zolmitriptan and propranolol showed decreased skin permeation rate. It was found that drug release was controlled by amide group through hydrogen bonding, and controlled release extent was positively correlated with hydrogen bonding strength.@*Conclusion@#From these results, we concluded that drugs with strong hydrogen bond forming ability and high skin permeation were suitable to use amide PSAs to regulate their release rate from patch.

Gender Differences in the Microanatomy of Skin of Palm in Humans

Knowledge of basic elements provides opportunity to make clear vision of structure of any organ. It is well known that accurate values of thickness of epidermis of skin and its variation with body site, age and sex are important in the fields of medical and biological research. The variations in skin reaction to certain stimuli could be due to biological factors such as the epidermal thickness, dermal thickness, distribution of epidermal appendages etc. Methods: Skin was procured from palm of six freshly embalmed human cadavers. Out of these three were males and three were females. Age of the male and female cadavers ranged between 60 to 70years (mean age 67years). Skin samples measuring 1cm (L) X 0.5cm (B) were taken from center of palm. Tissue was preserved in 10% formaldehyde for 48 hours. Fixed tissue specimens were dehydrated through increasing concentrations (30%, 50%, 70%, 90% and absolute) of ethanol. After clearing the tissue in xylene, embedding was done in paraffin wax. 5 µm thick sections were cut using rotary microtome. Whole thickness of tissue was sectioned. Haematoxylin[Harris’s] and Eosin stained section was observed for 3 different fields thus for each cadaver 27 observations were obtained. Results: In females thickness of epidermis(Edp) of were observed 404.43±23.41µm,thickness of stratum corneum (330±32.83µm),layers of stratum spinosum, stratum granulosum were 4 and 3 respectively, number of rete pegs (7.52±0.94), depth of rete pegs (195.78±18.05µm), thickness of papillary dermis and reticular dermis were(135.92±13.230µm) and (386.10±8.24µm) respectively. Whereas In males thickness of epidermis(Edp) of were observed (296.63±107.03µm),thickness of stratum corneum were (112.20±63.92µm),layers of stratum spinosum and stratum granulosum were 2, number of rete pegs 16.15±3.71, depth of rete pegs (104.56±15.28µm), thicknesss of papillary dermis and reticular dermis were(142.63±40.84µm) and (483.27±116.43µm) respectively. Conclusion: Despite of the fact that subjects from both sexes belonged to the same age group, clear and statistically significant histological differences were observed in the skin of palm. Females showed thicker epidermis as well as stratum corneum but thinner dermis in comparison to males. Males had more number of rete pegs but these are shallower than females.

Effect of the Hot Water Extract of Coix lacryma-jobi L. var. ma-yuen Stapf with Husks on Skin Improvement / 日本補完代替医療学会誌

We examined the influence of hot water extract of coix seed (Coix lacryma-jobi L. var. ma-yuen Stapf) with husks on facial skin. Ten females (28-58 years old) took hot water extract of coix seed with husks 1 g/day for 8 weeks, and various skin parameters were measured. The results showed that the total amount of subsurface reflection of blue light, which is an index of skin translucency, increased significantly after 8 weeks of intake (p = 0.011). In addition, skin texture improved significantly after 4 and 8 weeks of intake (p = 0.007, p = 0.042). Additionally, the condition of tape-stripped stratum corneum also indicated significant improvement after 4 and 8 weeks intake (p = 0.0002, p = 0.020). These results suggested that the hot water extract of coix seed with husks exhibited effects even at 1 g/day, which is less than in previous reports.

Effects of Frankincense and Myrrh essential oil on transdermal absorption of ferulic acid in Chuanxiong / 中国中药杂志

The aim of this paper was to explore the effects of Frankincense and Myrrh essential oil on transdermal absorption, and investigate the mechanism of permeation on the microstructure and molecular structure of stratum corneum. Through the determination of stratum corneum/medium partition coefficient of ferulicacid in Chuanxiong influenced by Frankincense and Myrrh essential oil, the effects of volatile oil of frankincense and Myrrh on the the microscopic and molecular structure of stratum corneum were explored by observation of skin stratum corneum structure under scanning electron microscopy, and investigation of frankincense and myrrh essential oil effects on the molecular structure of keratin and lipids in stratum corneum under Fourier transform infrared spectroscopy. The results showed that the oil could enhance the distribution of ferulic acid in the stratum corneum and medium, and to a certain extent damaged the imbricate structure of stratum corneum which was originally regularly, neatly, and closely arranged; some epidermal scales turned upward, with local peeling phenomenon. In addition, frankincense and myrrh essential oil caused the relative displacement of CH2 stretching vibration peak of stratum corneum lipids and amide stretching vibration peak of stratum corneum keratin, indicating that frankincense and myrrh essential oil may change the conformation of lipid and keratin in the stratum corneum, increase the bilayer liquidity of the stratum corneum lipid, and change the orderly and compact structure to increase the skin permeability and reduce the effect of barrier function. It can be concluded that Frankincense and Myrrh essential oil can promote the permeation effect by increasing the distribution of drugs in the stratum corneum and changing the structure of the stratum corneum.

Dexamethasone acetate microemulsions: formulation and effect on skin permeability / 药学学报

The present project was designed to optimize the microemulsion (ME) formulation of oil in water (O/W) for dexamethasone acetate (DA), and examine its impact on DA percutaneous permeation. The saturated solubility of DA in different oils, surfactants and co-surfactants was tested. The ratio of surfactant to co-surfactant was selected by constructing pseudo three phase diagrams to investigate the maximal microemulsion area. In vitro permeation studies of DA from microemulsion and suspension were performed to optimize the formulation further. Differential scanning calorimetry (DSC) and attenuated total reflection flourier transformed infrared spectroscopy (ATR-FTIR) were performed to investigate the mechanism of microemulsion action on skin. The optimized formulation was composed of oleic acid/Labrasol/propylene glycol/water with 8/45/15/32(w/w), and the DA loading was 0.75% (w/w). The permeation enhancement of microemusion was 6.00-fold as that of suspension, and the DA from microemulsion retained in the skin was 4.79-fold as that of suspension. DSC and ATR-FTIR results suggested that microemulsion could affect the intercellular lipid lamellae and keratin of the stratum corneum. The barrier function of stratum corneum was disordered by the microemulsion so that the dermal drug delivery was enhanced. Therefore, the optimized microemulsion enhanced DA percutaneous permeation significantly through the interaction of microemulsion with skin, microemulsion is a promising approach for DA percutaneous delivery.

Expression of stratum corneum chymotryptic enzyme and its significance in cervical adenocarcinoma / 肿瘤研究与临床

Objective To investigate the expression of stratum corneum chymotuptic enzyme (SCCE) and its significance in human cervical adenocarcinoma.Methods Immunohistochemistry was used to detect the expressions of SCCE,ER,CEA and Vimentin in tissues from the group of 45 cervical adenocarcinoma patients,group of 24 cervical glandular intraepithelial neoplasia (CGIN) patients and group of 24 normal cervical tissues.Results The expression of SCCE was 84.44 ％ (38/45),58.33 ％ (14/24) and 8.33 ％ (2/24) in 3 groups respectively.The SCCE expression from group of cervical adenocarcinoma were more significantly than that of normal cervical tissues (P ＜ 0.012 5),the expression of SCCE from group of CGIN were more significantly than that of normal cervical tissues (P ＜ 0.012 5),but there was no difference between the cervical adenocarcinoma and the CGIN on the expression of SCCE (P ＞ 0.012 5).Conclusion SCCE could be recommended as a new biomarker for the early screening cervical adenocarcinoma and as an additional marker for the prognosis of cervical adenocarcinoma.

Evaluation of skin hydration after exposition to the aqueous and hydroalcoholic bases and silicone emulsion.

Several dermocosmetic bases even without active substances, can increase the cutaneous hydration, resulting in a beneficial effect to the skin. The evidence and interpretation of possible hydration effect of formulations in the skin can be carried through by means of histopathological and histomorphometrical evaluation, a time that allows the analysis of the epithelial tissue, of dermis and also of the cellular characteristics. The objective of this research was to evaluate the skin hydration after exposition to the aqueous and hydroalcoholic bases and silicone emulsion. Swines had areas submitted to treatments during 15 days with three different formulations (F1 - aqueous gel, F2 - hydroalcoholic gel and F3 - silicone emulsion). By means of histometric and histopathological techniques were gotten the thickness of the epidermis and stratum corneum. Comparison of means was done using ANOVA followed by the Tukey test. The F1 provoked significant increase in the thickness of the epidermis. The formulaton F2 provoked significant reduction in the thickness of the epidermis and stratum corneum. F3 not presented significant difference in this structures. According to the study, the type of base chosen intervenes with the skin hydration.

Warming of one hand causes sustained increases in skin surface temperature and water content of the contralateral forearm / 体力科学

This study aimed to develop a new method of increasing water content in the cutaneous stratum corneum under a dry skin condition. For this purpose, the experiments were performed using 10 healthy women (age: 20 ± 5 years, height: 158 ± 4 cm, weight: 50 ± 6 kg) in winter to ensure the dry condition. The subjects immersed the right hand into a 42˚C bath for 10 min. Skin surface temperature and water content in the stratum corneum of the left forearm were simultaneously measured during and for 1 h after the hand warming. The skin surface temperature began to increase (P<0.05) 15 min after the hand warming and thereafter remained increased for 1 h. Similarly, the water content in the stratum corneum began to increase immediately after the hand warming and remained increased throughout the experiment. The present results suggest that warming of one hand is effective in enhancing skin moisture in the other forearm and thereby maintaining barrier function of the skin.

Ph de los jabones: un estudio observacional / SOAP PH: an observational study

La epidermis es la primera línea de defensa entre el cuerpo y el medioambiente, evitando que irritantes, alérgenos y microbios se penetren en el cuerpo. La capa más superficial se conoce como “mantoácido”. Cambios en el pH de esta capa provoca irritación y alteración de sus funciones. El agua y el jabón entre otros pro ductos cosméticos modifican el pH de 20 jabones de distintas marcas comerciales. Se observaron diferentes grados de alcalinidad entre los jabones estudiados. La mayoría de estos jabones resultaron de elevada alcalinidad, con pH que osciló entre 7.81 y 10.25.

The epidermis is the first line of defense between de body and thee nvironment. The epidermis prevents irritants, allergens and microbes from penetrating into the body. The most superficial layer is called “acidmantle”. The pH changes in this layer result in irritation and alteration of its functions. The pH is modified by water and soap, among other cosmetic products. The pH of 20 soaps of different trade marks was measured. Different alkalinity levels were observed in the studied soaps. Most of these soaps had a high level of alkalinity, with a pH that ranged from 7.81 to10.25.

Acute Modulations in Stratum Corneum Permeability Barrier Function Affect Claudin Expression and Epidermal Tight Junction Function via Changes of Epidermal Calcium Gradient

Tight junction (TJ) is recognized as a second barrier of the skin. Altered expression of TJ proteins in various skin diseases characterized by the abnormal permeability barrier such as psoriasis suggests that TJ could be affected by stratum corneum (SC) barrier status. However, the physiological relationship between SC and TJ barrier remains to be investigated. Therefore, we examined the effect of SC barrier disruption on the expression of TJ proteins, claudin (Cldn)-1 and Cldn-4, and TJ barrier function in hairless mouse skin. We also investigated whether the alterations in epidermal Ca2+ affected TJ proteins expression in vivo. Repeated tape-stripping induced a sequential change of the expression and function of TJ. As early as 15-30 minutes after tape-stripping, downregulation of Cldn-1 and Cldn-4 immunoreactivity and protein level without change in mRNA level was found. This was accompanied by the abnormal leakage of lanthanum. However, by 1 hour Cldn-1 and Cldn-4 immunolocalization recovered along with normalized lanthanum permeation pattern. Moreover, the mRNA and protein levels of Cldn-1 and Cldn-4 were increased by 1 to 6 hours after tape-stripping. Inhibition of calcium loss by immersion of barrier-disrupted skin into a high Ca2+ solution prevented the dislocation of Cldn-1 and Cldn-4. Occlusion of barrier-disrupted skin delayed the restoration of Cldn-1 and Cldn-4. Our results suggest that the alteration of epidermal Ca2+ gradient caused by SC barrier perturbation affects the TJ structure and function and the faster recovery of TJ as compared to the SC barrier may imply the protective homeostatic mechanism of skin barrier.

Avaliação da interação de compostos ativos hidratantes com modelo de biomembrana de Crotalus durissus por meio de calorimetria exploratória diferencial e espectroscopia RAMAN / Study of the interaction of moisturizers with a Crotalus durissus biomembrane by differential scanning calorimetry and RAMAN spectroscopy

O objetivo foi verificar as alterações no estrato córneo em modelos alternativos de membrana após a aplicação de ativos hidratantes envolvendo métodos biofísicos. O modelo de biomembrana utilizado foi a muda de pele de Crotalus durissus e os ativos hidratantes foram: uréia, silício orgânico, extrato vegetal de Imperata cylindrica, reação de xilitol e glicose e componentes de NMF. Os resultados da avaliação das alterações do modelo por meio de Espectroscopia Raman com Transformada de Fourier sugerem que os ativos hidratantes confirmam segurança necessária, pois não alteraram de forma acentuada a estrutura do estrato córneo. Utilizando-se Calorimetria Exploratória Diferencial pode-se indicar que a solução de silício orgânico e o gel hidrofílico com uréia apresentaram melhor poder hidratante.

The objective of this research was to use biophysical techniques to investigate the alterations induced in a biomembrane model of the stratum corneum by the application of moisturizers. The biomembrane was obtained from the skin shed by the rattlesnake Crotalus durissus and the active moisturizing compounds were: urea, dimethylsilanol hyaluronate, Imperata cylindrical plant extract, carbohydrates and natural moisturizing factors (NMF components). Results from FT-Raman spectroscopy suggested that the moisturizers were safe, since they did not promote modifications in the structure of the stratum corneum. Differential scanning calorimetry results indicated that the solution containing the organic silicon compound and the gel with urea showed the best hydrating effects on the stratum corneum.

Spectroscopic and thermal characterization of alternative model biomembranes from shed skins of Bothrops jararaca and Spilotis pullatus / Caracterização espectroscópica e térmica de biomembranas modelo alternativo de peles galpão de Bothrops jararaca e Spilotis pullatus

Recently, there has been an interest in the use of shed snake skin as alternative model biomembrane for human stratum corneum. This research work presented as objective the qualitative characterization of alternative model biomembranes from Bothrops jararaca and Spilotis pullatus by FT-Raman, PAS-FTIR and DSC. The employed biophysical techniques permitted the characterization of the biomembranes from shed snake skin of B. jararaca and S. pullatus by the identification of vibrational frequencies and endothermic transitions that are similar to those of the human stratum corneum.

Existe atualmente interesse no uso da muda de pele de cobra como modelos alternativos de biomembranas da pele humana. O presente trabalho apresentou como objetivo a caracterização qualitativa de modelos alternativos de biomembranas provenientes de mudas de pele de cobra da Bothrops jararaca e Spilotis pullatus por espectroscopia Raman (FT-Raman), espectroscopia fotoacústica no infravermelho (PAS-FTIR) e calorimetria exploratória diferencial (DSC). As técnicas biofísicas FT-Raman, PAS-FTIR e DSC permitiram caracterizar qualitativamente os modelos alternativos de biomembranas provenientes das mudas de pele de cobra da B. jararaca e S. pullatus e identificar freqüências vibracionais e transições endotérmicas similares ao estrato córneo humano.

In vitro safety assessment of papain on human skin: A qualitative Light and Transmission Electron Microscopy (TEM) study / Avaliação in vitro da segurança de uso da papaína em pele humana: Estudo qualitativo por microscopia de luz e eletrônica de transmissão (MET)

Papain is a thiol proteolytic enzyme widely used in dermatology that found applications in wound treatment. Recently, papain was also used as absorption enhancer which can modify the peptide/protein material in the bilayer domain. We investigated papain safety using human skin that was exposed to papain in vitro at different times: 4, 24 and 48 hours. The samples were examined using Light and Transmission Electron Microscopy (TEM) to study of the mechanisms involved in enhancer-skin interaction. After 24 hours, changes occurred in corneosomes. However, samples of 48 hours did not show major changes in agreement with the control. These findings indicated that papain could be used safely onto the skin.

Papaína é uma enzima proteolítica amplamente utilizada na dermatologia para o tratamento de feridas. Atualmente, a papaína também tem sido empregada como promotor de absorção cutânea passível de modificar os domínios protéicos da epiderme. Nesta pesquisa investigou-se in vitro a segurança da papaína, utilizando pele humana exposta a enzima em diferentes períodos de tempo de contato: 4, 24 e 48 horas. As amostras foram avaliadas por Microscopia de Luz e Eletrônica de Transmissão (MET), técnicas que podem ser utilizadas no estudo dos mecanismos envolvidos na interação de promotores de absorção cutânea e a pele. Após 24 horas de contato entre a pele a solução de papaína, mudanças ocorreram nos corneossomos, no entanto, as amostras em contato por 24 horas não evidenciaram alterações relevantes comparadas com o controle. Os resultados indicaram que a papaína poderia ser seguramente aplicada sobre a pele.

The Effect of Prolonged Water Exposure on the Epidermal Permeability Barrier / 대한피부과학회지

BACKGROUND: Water exposure is considered an important causative factor of irritant contact dermatitis. It is also known that water exposure can disrupt the stratum corneum (SC). However, there are only a few morphologic studies on the effect of water contact on the skin. OBJECTIVE: The aim of our study was to investigate the effects of prolonged water exposure on the permeability barrier and the ultrastructure of the SC intercellular lipids. METHODS: After prolonged water exposure of hairless mouse skin in vivo for 24, 36, 48, and 72 hrs respectively, the permeability barrier function was assessed by transepidermal water loss (TEWL) measurement, and the ultrastructure of SC by electron microscopy using osmium tetraoxide and ruthenium tetraoxide postfixation and calcium ion capture cytochemistry. Additionally, the lipid composition was evaluated using confocal microscopy with nile red stain and the integrity of the SC assessed using a lanthanum tracer. RESULTS: After prolonged water exposure, water caused a significant increase in TEWL with disappearance of the calcium gradient, but this did not significantly influence the recovery rate of TEWL. The intercellular lipids were disrupted, and multiple lacunae containing abnormal delaminated materials within the intercellular spaces were observed. Lanthanum tracer penetrated into the intercellular space of the SC. There was a progressive decrease in nile red staining with neutral lipid content. With increasing exposure to water, these results were more evident. CONCLUSION: Our results provide a better understanding of the disruptive effect of prolonged water exposure on barrier lipids, the penetration-enhancing effect of water and the increased susceptibility to irritants, with regard to duration of water exposure.

Change of Skin Barrier Function According to Stratum Corneum Removal by Tape Stripping / 대한피부과학회지

BACKGROUND: The major function of the skin is to prevent loss of water and electrolytes and transepidermal penetration of harmful materials. The stratum corneum is known to play a major role in the skin barrier function. Tape stripping (TS) with adhesive cellophane tape is one of the best method of removing the stratum corneum on the skin surface, and has been used in studies of the skin barrier function when investigating material distribution in the stratum corneum and transepidermal absorption of drugs. OBJECTIVE: This study was performed to evaluate the skin barrier function according to removal of the stratum corneum by TS. METHOD: Six vitiligo patients who had undergone autologous suction blister grafting were tested. Transepidermal water loss (TEWL) was measured on the normal skin of the buttocks in each patient after every fifth TS, plus on the skin where the entire epidermis had been removed by autologous suction blister grafting. We compared these two values and also examined morphological change of the stratum corneum after TS, by both light and electron microscope. RESULTS: The TEWL value slightly increased when TS was carried out up to 30 times, but greatly increased to 20g/m2h of TEWL when TS was done 30-40 times. Thereafter, no increase in TEWL was observed when TS was carried out up to 100 times. The pattern of TEWL according to numbers of TS approximately plotted a sigmoid curve. On average, there was about 88% impairment to the skin permeability barrier function after TS. When the TEWL increased to more than 70g/m2h over baseline TEWL, the stratum corneum was almost removed, as revealed by light and transmission electron microscope. CONCLUSION: The stratum corneum acts as a major skin barrier, and the mid to lower portion of the entire stratum corneum appears to play a significant role in the skin permeability barrier function.