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.

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.

Topical Applications of Thiosulfinate-Enriched Allium sativum Extract Accelerates Acute Cutaneous Wound Healing in Murine Model / 中国结合医学杂志

OBJECTIVE@#To determine whether topical applications of thiosulfinate-enriched Allium sativum extract (TASE) can accelerate acute cutaneous wound healing (WH) in a murine model.@*METHODS@#Keratinocyte viability and in vitro wound closure were assessed in keratinocyte cultures. Effects of topical TASE (0.5 μg/mL of allicin in 97% ethanol) on acute cutaneous WH were determined in a murine model of acute cutaneous wound. Twelve mice were alternately assigned to the vehicle- and TASE-treated groups (n=6 per group). Expression levels of mRNA for keratinocyte differentiation marker-related proteins (filaggrin, loricrin and involucrin) and lipid synthetic enzymes (elongation of very long chain fatty acids protein 4 (ELOVL4), fatty acid synthase (FA2H), 3-hydroxy- 3-methyl-glutaryl-coenzyme A reductase (HMGCoA), and serine palmitoyltransferase (SPT)) were assessed using real-time quantitative polymerase chain reaction on day 3 and 8 after wounding, while transepidermal water loss (TEWL) rates were measured in wounded areas.@*RESULTS@#TASE accelerated WH both in vivo (40% vs. 22% reduction in wound area, P<0.01) and in vitro (90% vs. 65% reduction in wound area, P<0.01). Moreover, topical applications of TASE upregulated the expression levels of epidermal mRNA for ELOVL4, HMGCoA, SPT, filaggrin, loricrin and involucrin (P<0.05 vs. vehicle-treated controls) on day 3 after wounding. Likewise, TASE significantly lowered TEWL rates in comparison with vehicle alone on day 8 (33.06±2.09 g/(m@*CONCLUSIONS@#Topical applications of TASE stimulated keratinocyte proliferation and formation of epidermal permeability barrier function, leading to acceleration of acute cutaneous WH. Topical products containing TASE could be used to manage acute cutaneous WH.

Herbal Medicines Prevent the Development of Atopic Dermatitis by Multiple Mechanisms / 中国结合医学杂志

Atopic dermatitis (AD) is among the most common skin disorders in humans. Although a variety of regimens are available for the treatment of AD, preventive approaches are limited. Recent studies have demonstrated that certain naturally-occurring herbal medicines are effective in preventing the development of AD via divergent mechanisms, such as inhibiting cytokine and chemokine expression, IgE production, inflammatory cell infiltration, histamine release, and/or enhancement of epidermal permeability barrier function. Yet, they exhibit few adverse effects. Since herbal medicines are widely available, inexpensive and generally safe, they could represent an ideal approach for preventing the development of AD, in both highly developed and developing countries.

Therapeutic Benefits of Natural Ingredients for Atopic Dermatitis / 中国结合医学杂志

Although a variety of regimens are available for the treatment of atopic dermatitis (AD), severe adverse reactions and unpopular costs often limit their usage. In contrast, certain inexpensive, naturally-occurring ingredients are proven effective for AD with fewer side effects. The beneficial effects of these ingredients can be attributed to inhibition of cytokine and chemokine expression, IgE production, inflammatory cell infiltration, histamine release, and/or the enhancement of epidermal permeability barrier function. Since herbal medicines are widely available, inexpensive and generally safe, they could be valuable alternatives for the treatment of AD, particularly for those patients who are not suitable for the utilization of immune modulators. In this review, we summarize the therapeutic benefits of natural ingredients for the treatment of AD and the mechanisms of their actions.

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.

Preventive Effects of Multi-Lamellar Emulsion on Low Potency Topical Steroid Induced Local Adverse Effect

BACKGROUND: Topical steroid treatment induces diverse local Wand systemic adverse effects. Several approaches have been tried to reduce the steroid-induced adverse effects. Simultaneous application of physiological lipid mixture is also suggested. OBJECTIVE: Novel vehicles for topical glucocorticoids formulation were evaluated for the efficacy of reducing side-effects and the drug delivery properties of desonide, a low potency topical steroid. METHODS: Transcutaneous permeation and skin residual amount of desonide were measured using Franz diffusion cells. The in vivo anti-inflammatory activity was evaluated using murine model. RESULTS: Topical steroids formulation containing desonide, in either cream or lotion form, were prepared using multi-lamellar emulsion (MLE), and conventional desonide formulations were employed for comparison. MLE formulations did not affect the anti-inflammatory activity of the desonide in phobol ester-induced skin inflammation model, compared with conventional formulations. While the penetrated amounts of desonide were similar for all the tested formulations at 24 hours after application, the increased lag time was observed for the MLE formulations. Interestingly, residual amount of desonide in epidermis was significantly higher in lotion type MLE formulation. Steroid-induced adverse effects, including permeability barrier function impairment, were partially prevented by MLE formulation. CONCLUSION: Topical desonide formulation using MLE as a vehicle showed a better drug delivery with increased epidermal retention. MLE also partially prevented the steroid-induced side effects, such as skin barrier impairment.

Pseudoceramide-Containing Physiological Lipid Mixture Reduces Adverse Effects of Topical Steroids

PURPOSE: Various therapeutic approaches have been suggested for preventing or reducing the adverse effects of topical glucocorticoids, including skin barrier impairment. Previously, we have shown that impairment of skin barrier function by the highest potency topical glucocorticoid, clobetasol 17-propinate (CP), can be partially prevented by co-application of a physiological lipid mixture containing pseudoceramide, free fatty acids, and cholesterol (multi-lamellar emulsion [MLE]). Skin atrophic effects of CP were also partially reduced by MLE. In this study, the preventive effects of MLE on the lowest potency topical glucocorticoid, hydrocortisone (HC), were investigated using animal models. METHODS: Anti-inflammatory activity of topical HC was evaluated using a 12-O-tetradecanoylphobol-13-acetate-induced skin edema model. Topical steroid induced adverse effects were evaluated using hairless mouse. RESULTS: The results showed that the anti-inflammatory activity was not altered by co-application of either MLE or hydrobase. However, co-application of MLE and 1.0% HC showed less impairment in the epidermal permeability barrier function, skin hydration, and skin surface pH compared with hydrobase. Stratum corneum integrity, evaluated by measuring trans-epidermal water loss after repeated tape stripping, showed less damage with MLE co-application. Long-term application of topical HC induced skin atrophy, measured by a reduction in skinfold and epidermal thickness and in the number of epidermal proliferating cell nucleus antigen (PCNA)-positive keratinocytes. Co-application of MLE did not affect the skinfold or epidermal thickness, but the number of PCNA-positive keratinocytes was less decreased with MLE use. CONCLUSIONS: These results suggest that co-application of MLE is effective in reducing the local adverse effects of low-potency topical glucocorticoids and supports the therapeutic efficacy of physiological lipid mixtures on skin barrier function.

Changes of Antimicrobial Peptides and Transepidermal Water Loss After Topical Application of Tacrolimus and Ceramide-dominant Emollient in Patients with Atopic Dermatitis

Increased transepidermal water loss (TEWL) and downregulated antimicrobial peptides (AMPs) are observed in patients with atopic dermatitis (AD). Tacrolimus and ceramide-dominant emollients are effective in the treatment of AD by preventing the production of inflammatory cytokines and by correcting skin barrier dysfunctions, respectively. Present study was designed to investigate the relationship between antimicrobial and barrier factors by measuring the changes of AMPs and TEWL after topical application of tacrolimus and ceramide-dominant emollient in the patients with AD. A total of three patients with AD were treated with tacrolimus in one lesion and ceramide-dominant emollient in another lesion for 4 weeks. RT-PCR and western blotting revealed that the mRNA and protein expression levels of hBD-2 and LL-37 were increased on the both study sites. Immunohistochemical analysis showed significant increase of AMPs and IL-1alpha, while, IL-4 was decreased on the both study sites. The mean changes of TEWL and AMPs showed no statistical difference between both sites. Tacrolimus and ceramide-dominant emollient influence on both TEWL and AMPs expression in patients with AD, namely they have similar effects on both of the two. This study shows that restoration of permeability barrier function is accompanied by the concomitant improvement of antimicrobial defense in patients with AD.

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.

An Update of the Defensive Barrier Function of Skin

Skin, as the outermost organ in the human body, continuously confronts the external environment and serves as a primary defense system. The protective functions of skin include UV-protection, anti-oxidant and antimicrobial functions. In addition to these protections, skin also acts as a sensory organ and the primary regulator of body temperature. Within these important functions, the epidermal permeability barrier, which controls the transcutaneous movement of water and other electrolytes, is probably the most important. This permeability barrier resides in the stratum corneum, a resilient layer composed of corneocytes and stratum corneum intercellular lipids. Since the first realization of the structural and biochemical diversities involved in the stratum corneum, a tremendous amount of work has been performed to elucidate its roles and functions in the skin, and in humans in general. The perturbation of the epidermal permeability barrier, previously speculated to be just a symptom involved in skin diseases, is currently considered to be a primary pathophysiologic factor for many skin diseases. In addition, much of the evidence provides support for the idea that various protective functions in the skin are closely related or even co-regulated. In this review, the recent achievements of skin researchers focusing on the functions of the epidermal permeability barrier and their importance in skin disease, such as atopic dermatitis and psoriasis, are introduced.

An Update of the Defensive Barrier Function of Skin

Skin, as the outermost organ in the human body, continuously confronts the external environment and serves as a primary defense system. The protective functions of skin include UV-protection, anti-oxidant and antimicrobial functions. In addition to these protections, skin also acts as a sensory organ and the primary regulator of body temperature. Within these important functions, the epidermal permeability barrier, which controls the transcutaneous movement of water and other electrolytes, is probably the most important. This permeability barrier resides in the stratum corneum, a resilient layer composed of corneocytes and stratum corneum intercellular lipids. Since the first realization of the structural and biochemical diversities involved in the stratum corneum, a tremendous amount of work has been performed to elucidate its roles and functions in the skin, and in humans in general. The perturbation of the epidermal permeability barrier, previously speculated to be just a symptom involved in skin diseases, is currently considered to be a primary pathophysiologic factor for many skin diseases. In addition, much of the evidence provides support for the idea that various protective functions in the skin are closely related or even co-regulated. In this review, the recent achievements of skin researchers focusing on the functions of the epidermal permeability barrier and their importance in skin disease, such as atopic dermatitis and psoriasis, are introduced.

The Effects of Strontium Ions on Epidermal Permeability Barrier / 대한피부과학회지

BACKGROUND: Several ions, such as calcium or magnesium ions, are reported to have regulatory effects on epidermal permeability barrier homeostasis. Recently, it has been suggested that strontium ion can play a substitutive role for calcium ion in various cellular reactions. OBJECTIVE: This study was conducted to investigate the effects of strontium ion, either alone or in combination with calcium or magnesium ions, on epidermal permeability barrier homeostasis. METHODS: Female hairless mice were used to study the effects of various ions on epidermal permeability barrier recovery. Calcium chloride solution, magnesium chloride solution or strontium chloride solution were topically applied to barrier-disrupted skin, either alone or simultaneously. Change of transepidermal water loss, which represents permeability barrier function, was measured by TEWameter and morphological change was also observed by light and electron microscopy. RESULTS: Topical application of strontium chloride solution accelerated permeability barrier recovery rate, compared with vehicle-applied skin. Magnesium chloride solution also accelerated barrier recovery rate, as reported in previous studies. Interestingly, simultaneous application of strontium and calcium ions significantly accelerated barrier recovery rate, compared to application of strontium or calcium ion alone. Nile red staining confirmed the increased neutral lipid deposition in strontium ion applied skin. Electron microscopic observation also revealed an increased lamellar body secretion in strontium ion applied skin. CONCLUSION: Strontium ion can play a regulatory role in epidermal permeability barrier homeostasis due to, at least in part, its competitive action on calcium ion for the same ion channel.

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.

The Effect of Ultrasound on Epidermal Permeability Barrier and Lipid Synthesis / 대한피부과학회지

BACKGROUND: Abrogation of the epidermal permeability barrier results in an increased lipid synthesis and lipid synthetic enzymes. Recent studies have shown that ultrasound can induce changes in the epidermal calcium gradient that increase lamellar body secretion without increasing transepidermal water loss (TEWL). OBJECTIVE: We undertook this study to identify whether ultrasound can stimulate lipids synthetic enzymes and lipids synthesis. METHODS: Ultrasounds were applied to the skin of hairless mice, and we then quantified lipid synthesis, real time RT-PCR to measure mRNA activities of lipid synthetic enzymes and TEWL. We also performed RuO4 post fixation and calcium ion capture cytochemistry. RESULTS: There were no significant changes of TEWL before and after ultrasound treatment. Calcium in upper epidermis decreased and that in lower epidermis increased after treatment of ultrasound and some recovery of epidermal calcium gradient after 6 hours. In RuO4 post fixation, lacuna dilatation, partial distension of intercorneocyte space, loss of multilamellar structures and increased lamellar body secretion were observed in the epidermis of the ultrasound treated hairless mice. The mRNA levels of 3-hydroxy 3-methylglutaryl coenzyme A (HMG CoA) reductase, serine palmitoyl transferase (SPT), fatty acid synthase (FAS) and lipid synthesis were increased in the epidermis of the ultrasound treated hairless mice. CONCLUSION: Ultrasound can increase mRNA of lipids synthetic enzymes and lipids synthesis without increasing TEWL by changing calcium ion gradients.

Comparison of the Effect of Various Chemical Peeling Agents on the Skin Barrier / 대한피부과학회지

BACKGROUND: Among the various methods for chemical peeling, it is possible to select a wide range of peeling agents for particular patients. OBJECTIVES: The objective of present study was to investigate the effects of various chemical peeling agents on the epidermal permeability barrier of hairless mice skin and to clarify the histologic alteration in epidermal structure, thus to apply in the clinical practices. METHODS: We have applied 35% and 70% glycolic acid (GA) aqueous solutions, 30% of salicylic acid (SA) solution of PEG400, Jessner's solution and 15%, 30% and 50% of trichloroacetic acid (TCA) aqueous solution to the flank of hairless mice. TEWL (trans-epidermal water loss) values were measured before and immediately after the application and 3, 6, 12 and 24 hours following treatment. Biopsy specimens were evaluated with light and electron microscopy for epidermal structural changes. RESULTS: There were no significant changes in TEWL for the GA and SA solution treated skin, regardless of their concentration. For the TCA and Jessner's solution, TEWL increased immediately after treatment and recovered the basal levels about 90% after 24 hours for Jessner's solution and low concentrated TCA solution, but did not recovered for high concentrated TCA solution. On light and electron microscopic examination, exfoliating effect was seen in every case and as for SA and Jessner's solution treated skin, keratolysis at hair follicles was also seen. Slight epidermal necrosis was seen in every case, except in GA treated skin. CONCLUSION: The present results suggest that using topical agents such as glycolic acid can induce the change in the architecture of the epidermis without disrupting the skin barrier.

The Effects of Change in Epidermal Calcium Gradient on Keratinocyte Differentiation / 대한피부과학회지

BACKGROUND: The cornified cell envelope(CE) which is formed during the terminal differentiation of keratinocytes, is a specialized structure which forms a structurally and functionally complete permeability barrier. OBJECTIVE: The purpose of our study is to investigate the effects of changes in the calcium ions on keratinocyte differentiation, especially in the expression of CE protein. METHODS:The permeability barrier of hairless mice was disrupted by tape-stripping and then exposed to the air or occluded with a water-vapor impermeable membrane, and iontophoresis was done without permeability barrier perturbation. Skin specimens were prepared for ion capture cytochemistry and immunohistochemistry with anti-K5, anti-K10, anti-K6, anti-involucrin and anti-loricrin. RESULTS: The calcium gradient which disappeared after tape-stripping was restored at 36 h after tape-stripping with air exposure and at 60 h after tape-stripping with occlusion. The change in calcium ions produced by both positive and negative iontophoresis showed recovery at 6 h. Expression of basal K5 showed a slight decrease and expression of suprabasal K10 showed an increase at 12 h with air exposure after tape-stripping, tape stripping with occlusion, and iontophoresis. Expression of K6 appeared at 12 h after tape-stripping and then in the whole epidermis at 36 h with air exposure after tape-stripping and tape stripping with occlusion and focally appeared in the stratum granulosum and stratum spinosum after iontophoresis. Expression of involucrin was increased at 12 h with air exposure after tape-stripping and iontophoresis and was extended to the lower spinous layers in tape-stripping with occlusion. Expression of loricrin in air exposure after tape-stripping, tape-stripping with occlusion and iontophoresis was similar to that of normal skin. CONCLUSION: The changes in calcium ions without permeability barrier perturbation are related to the expression of CE protein. It is thought that calcium ions in the epidermis have an important role in the terminal differentiation of keratinocytes.

The Effects of Change in Epidermal Calcium Gradient on Keratinocyte Differentiation / 대한피부과학회지

BACKGROUND: The cornified cell envelope(CE) which is formed during the terminal differentiation of keratinocytes, is a specialized structure which forms a structurally and functionally complete permeability barrier. OBJECTIVE: The purpose of our study is to investigate the effects of changes in the calcium ions on keratinocyte differentiation, especially in the expression of CE protein. METHODS:The permeability barrier of hairless mice was disrupted by tape-stripping and then exposed to the air or occluded with a water-vapor impermeable membrane, and iontophoresis was done without permeability barrier perturbation. Skin specimens were prepared for ion capture cytochemistry and immunohistochemistry with anti-K5, anti-K10, anti-K6, anti-involucrin and anti-loricrin. RESULTS: The calcium gradient which disappeared after tape-stripping was restored at 36 h after tape-stripping with air exposure and at 60 h after tape-stripping with occlusion. The change in calcium ions produced by both positive and negative iontophoresis showed recovery at 6 h. Expression of basal K5 showed a slight decrease and expression of suprabasal K10 showed an increase at 12 h with air exposure after tape-stripping, tape stripping with occlusion, and iontophoresis. Expression of K6 appeared at 12 h after tape-stripping and then in the whole epidermis at 36 h with air exposure after tape-stripping and tape stripping with occlusion and focally appeared in the stratum granulosum and stratum spinosum after iontophoresis. Expression of involucrin was increased at 12 h with air exposure after tape-stripping and iontophoresis and was extended to the lower spinous layers in tape-stripping with occlusion. Expression of loricrin in air exposure after tape-stripping, tape-stripping with occlusion and iontophoresis was similar to that of normal skin. CONCLUSION: The changes in calcium ions without permeability barrier perturbation are related to the expression of CE protein. It is thought that calcium ions in the epidermis have an important role in the terminal differentiation of keratinocytes.

The Change of Epidermal Calcium Gradient: Confocal Laser Scanning Microscopic Approach / 대한피부과학회지

BACKGROUND: Ion capture cytochemistry(the potassium oxalate pyroantimonate method), semi- quantitatively, and proton probe X-ray microanalysis, quantitatively, have been applied to investigate the epidermal calcium distribution. OBJECTIVE: In this study, we examined the epidermal calcium distribution with confocal laser scanning microscopy(CLSM) in an attempt to evaluate the possibility of another method in epidermal calcium study. METHODS: The change of epidermal calcium distribution after barrier perturbation with tape stripping was investigated with CLSM and was compared to the results of ion capture cytochemistry. RESULTS: The calcium distribution pattern in normal murine epidermis demonstrated by CLSM show a normal calcium gradient, from a low level of calcium ions in the basal and spinous layer, followed by a progressive increase with a level of calcium ions reaching its maximal density within the outer stratum granulosum. Disruption of the epidermal barrier with tape stripping induced an immediate loss of the calcium gradient and the calcium gradient after 36h was almost normalized, in parallel with the recovery of barrier function. CONCLUSION: These results show that calcium gradient in murine epidermis after tape-stripping is restored by 36h and CLSM study can be used as a new method in epidermal calcium study.

The Changes in the Skin Permeability Barrier and Epidermais of Hairless Mouse on Oleic Acid Treatment / 대한피부과학회지

BACKGROUND: The stratum corneum(SC) inhibits t,ransepidermal water loss and makes a permeability barrier against foreign materials, so strategies to overcome relative impermeability of the SC is very important in transdermal drug delivery. This includes occlusion, hydration, chemical permeation enhancers, iontophoresis and sonophoresis, Oleic acid, which is one of the cis-unsaturated fatty acid and chemical permeation enhancers, increases the permeability of the lipophilic molecules and polar miolecules through the SC. By spectrometry, calorimetry and the flux technique, the hypothesis that oleic acid does exist as a liquid within the SC lipids and enhances the transport of polar molecules across the SC by the formation of permeable interfacial defects within the SC lipid bilayers was suggested. Also, repeated application of oleic acid induces epidermal proliferation, hyperkeratosis and sebaceous gland hyperplasia', However the exact pathomechanism was not reported. OBJECTIVE: We carried out some research to observe the mechanism by which oleic acid in creases transdermal drug delivery and the effect to the skin permeability barrier and epidermis by repeated application. METHODS: In the repeated treatment group, hairless mice(6 to 8 weeks) were treated with oleic acid once a day for 7 days unilaterally, and in the single treatment group, only one time, Transepidermal water loss(TEWL) was checked at 24hour after 1, 3 and 7 days of treatment and at, 1 hour, 6 hours, 24 hours, 72 hours after single treatment. Biopsies were taken from treated and controlateral(control) sides immediately after the TEWL checks at each time for light microscopic(H & E stain) and electron microscopic studies. RESULTS: In the repeated treatment group, TEWL was increased by day and epidermal proliferation and hyperkeratosis were also increased. In the single treatment group, TEWL was highly increased in the treated site at 1 hour after treatment and decreased with time. By electronmicroscope, we observed dilated lacunae, intrcellular lipid structural abnormalities and loss of normal calcium gradient. CONCLUSION: The possible domains of the epidermis interacting with oleic acid as a penetration enhancer are the lacunae and liipid bilayer by EM. The suggested pathomechanism of the epidermal changes, epidermal proliferation and hyperkeratosis was increased DNA synthesis of epidermal cells by the loss of epidermal calcium gradient in chronic barrier impairment.