Cyanoacrylate Stripping Research Articles

Barrier-disrupted skin: Quantitative analysis of tape and cyanoacrylate stripping efficiency by multiphoton tomography.

Numerous studies have employed tape stripping (TS) or cyanoacrylate stripping (CS) to induce skin barrier disruption of the stratum corneum (SC) in human and porcine skin. However, the thickness of the remaining SC and the respective changes of the skin permeability have been rarely quantified. By using high-resolution multiphoton tomography, about 5µm thick SC was found remaining on human skin after the performance of 30 times TS or 2 times CS. 50 tape strips or 4 times CS removed the entire human SC, but on porcine skin 2-3µm thick SC was still left. TS can only reach the transition zone between the SC and the stratum granulosum because of the limited adhesion, whereas CS was able to remove viable skin layers. Permeation investigations on porcine skin revealed that the apparent permeability coefficient of the hydrophilic nitroxide spin 2,5,5-Tetramethyl-1-pyrrolidinyloxy-3-carboxylic acid increased 15-, 18-, and 21-fold when the SC amount remaining in the skin was 30%, 16%, and 8%, respectively. It is recommended to use at most 30 times TS or 3 times CS to obtain ex vivo barrier-disrupted skin that mimics diseased skin. The study provides quantitative information for the utility of TS and CS in skin penetration research.

An ex vivo human skin model for studying skin barrier repair

In the studies described in this study, we introduce a novel ex vivo human skin barrier repair model. To develop this, we removed the upper layer of the skin, the stratum corneum (SC) by a reproducible cyanoacrylate stripping technique. After stripping the explants, they were cultured in vitro to allow the regeneration of the SC. We selected two culture temperatures 32 °C and 37 °C and a period of either 4 or 8 days. After 8 days of culture, the explant generated SC at a similar thickness compared to native human SC. At 37 °C, the early and late epidermal differentiation programmes were executed comparably to native human skin with the exception of the barrier protein involucrin. At 32 °C, early differentiation was delayed, but the terminal differentiation proteins were expressed as in stripped explants cultured at 37 °C. Regarding the barrier properties, the SC lateral lipid organization was mainly hexagonal in the regenerated SC, whereas the lipids in native human SC adopt a more dense orthorhombic organization. In addition, the ceramide levels were higher in the cultured explants at 32 °C and 37 °C than in native human SC. In conclusion, we selected the stripped ex vivo skin model cultured at 37 °C as a candidate model to study skin barrier repair because epidermal and SC characteristics mimic more closely the native human skin than the ex vivo skin model cultured at 32 °C. Potentially, this model can be used for testing formulations for skin barrier repair.

Dermatophagoides farinae house dust mite allergen challenges reduce stratum corneum ceramides in an experimental dog model of acute atopic dermatitis

Ceramides are essential stratum corneum (SC) lipids and they play a pivotal role in maintaining effective cutaneous barrier function. The present study aimed at determining the effect of a Dermatophagoides farinae house dust mite (Df-HDM) allergen challenge on SC ceramides of atopic dogs experimentally sensitized to these allergens. Six Df-HDM-sensitized atopic Maltese-beagle dogs were used. Prechallenge SC was obtained by cyanoacrylate stripping. One week later, the dogs were challenged topically with Df-HDM allergens, which resulted in mild to moderate inflammation 24 h later. Two weeks after challenge, SC of lesional and nonlesional skin was obtained. Finally, SC was collected from challenge sites 2 months after lesion resolution. The different SC lipids were quantified blindly by thin-layer chromatography. Significantly lower amounts of ceramides [AH], [AP], [AS], [NP], [EOP], [NS] and [EOS] were observed in lesional SC compared with prechallenge samples, while no significant effect was found on the amount of other lipids, including cholesterol and free fatty acids. The ceramide profile of nonlesional skin generally showed the same postchallenge reduction pattern. Ceramide amounts returned to normal within 2 months after lesion remission. These findings suggest that the allergic reactions caused by Df-HDM allergens lead to a selective reduction of SC ceramides, not only at sites of inflammation but also at sites away from those of allergen application. There is normalization of ceramide amounts after inflammation subsides. These observations suggest that the deficiency of ceramides observed in canine atopic skin occurs, at least in part, secondary to inflammation.

Confocal Raman Microspectroscopy for Evaluating the Stratum Corneum Removal by 3 Standard Methods

Background/Aims: Stratum corneum (SC) removal is needed in biopharmaceutical studies or in evaluating the barrier function. The most common technique is the tape stripping method. However, it results in neither a homogeneous nor a complete removal. Methods: The removal qualities of tape stripping, cyanoacrylate skin surface biopsy and trypsinization were estimated in vitro via histological imaging and confocal Raman microspectroscopy (CRM) and compared. In addition, the potential of the noninvasive CRM as a replacement method is discussed. Results: Comparison between the 3 methods showed, as expected, that the tape stripping method did not result in a uniform removal over the whole surface even after 28 strips. The trypsinization and cyanoacrylate skin surface biopsies allowed a complete and uniform removal of the SC after defining a standard protocol (2 cyanoacrylate strips with a polymerization time of 15 min). Conclusion: The feasibility of CRM to control SC removal was demonstrated in vitro. Tape stripping is a simple method, but it is influenced by many extrinsic factors and axial drug quantification is difficult. With trypsinization and cyanoacrylate methods, the entire SC is removed so that quantification over the whole SC is possible but not an axial drug screening.

Study on penetration of titanium dioxide (TiO2) nanoparticles into intact and damaged skin in vitro

It is important for toxicological assessment of nanoparticles to determine the penetration of nanoparticle in skin qualitatively and quantitatively. Skin penetration of four different types of rutile titanium dioxide (TiO(2)) (T-35, 35 nm, non-coating; TC-35, 35 nm, with almina/silica/silicon coating; T-disp, 10 x 100 nm, mixture of almina coated and silicon coated particles, dispersed in cyclopentasiloxan; T-250, 250 nm, non-coating) was determined with in vitro intact, stripped, and hair-removed skin of Yucatan micropigs to study the effect of dispersion and skin conditions. The TiO(2) was suspended in a volatile silicone fluid used for cosmetics, cyclopentasiloxane, at a concentration of 10%. The suspension was applied at a dose 2 microl/cm(2) for 24 hr, followed by cyanoacrylate stripping. The Ti concentration in skin was determined by ICP-MS. T-35 and T-250 easily aggregated in suspension with a mean diameter greater than 1 microm. TC-35 and T-disp showed good dispersion properties with a mean diameter in suspension of approximately 100 nm. No penetration was observed regardless of TiO(2) type in intact and stripped skin. The concentration of Ti in skin was significantly higher when TC-35 was applied on hair-removed skin. SEM-EDS observation showed that Ti penetrated into vacant hair follicles (greater than 1 mm below the skin surface), however, it did not penetrate into dermis or viable epidermis.

Characterization and quantification of ceramides in the nonlesional skin of canine patients with atopic dermatitis compared with controls

As in humans, there is mounting evidence in support of an abnormal skin barrier contributing to the pathogenesis of canine atopic dermatitis (AD). Studies in people with AD have associated an abnormal skin barrier with deficiencies in ceramides, which represent important components of the stratum corneum (SC) intercellular lipid lamellae. Therefore, the goal of this study was to determine if the SC of dogs with AD is deficient in ceramides compared to normal dogs. Samples of SC were obtained from nonlesional skin of the caudal abdomen of 14 patients with AD and 14 age-, breed- and sex-matched healthy controls using a cyanoacrylate stripping procedure, and the subclass and relative amount of ceramides were assessed blindly by thin layer chromatography. Paired t-tests using R statistical computer software revealed the percentage amounts of ceramides 1 and 9 were significantly lower in nonlesional skin of AD dogs compared to controls (P= 0.034 and P= 0.047, respectively), and the cholesterol percentage amount was significantly higher in AD dogs than in controls (P= 0.016). Furthermore, the cholesterol/ceramide ratio was significantly higher in the AD group with respect to controls (P= 0.014). These findings suggest that decreased amounts of ceramides in the skin of dogs with AD may be involved in the impaired barrier function of their skin.

Control of microcomedone formation throughout a maintenance treatment with adapalene gel, 0.1%

Microcomedones representing the clinically non-visible central precursor lesions of acne are induced by sebaceous hyperplasia as well as altered follicular growth and differentiation, and evolve into both comedones and inflammatory lesions. Thus, targeting microcomedone formation is essential in the prevention and therapeutic control of acne. The aim of this study was to assess the capacity of adapalene gel, 0.1%, to control the number of microcomedones after a combination treatment followed by a maintenance treatment. This was a single-site exploratory study in subjects with a diagnosis of mild to moderate acne vulgaris and the presence of at least 250 microcomedones per cm(2) at screening visit, counted via cyanoacrylate strips (CyASt). During the first 8 weeks, a combination of adapalene gel (0.1%) and benzoyl peroxide gel (2.5%) was applied. During the randomized, investigator-blinded, and vehicle-controlled 12-week maintenance phase, adapalene once daily (QD), or adapalene alternately with its vehicle once daily every other day (QoD), or vehicle QD were applied to the face. CyASt sampling on the forehead was done at baseline, week 8, and week 20. Lesion counting allowing calculating a defined success rate was done at all visits. A total of 54 subjects entered the combination phase, and 49 subjects were randomized into the maintenance phase: 16 in both the adapalene QD and the QoD group and 17 subjects receiving the vehicle. The microcomedone median count decreased for all groups until week 8 (end of combination phase) from 319 to 157. Microcomedone counts at the end of the maintenance phase (week 20) showed a significant percent difference (P = 0.04) between adapalene QoD (-53.5) and the vehicle (-42.1) and between adapalene QD (-50.6) and the vehicle (P = 0.037) compared with baseline. The application of adapalene gel, 0.1% monotherapy daily, or alternately every other day, significantly helps to control the microcomedone count during a 12-week maintenance treatment after a previous combination therapy with benzoyl peroxide in patients with mild to moderate acne.

Lymecycline and Minocycline in Inflammatory Acne

Background: Some antibiotics represent a mainstay in acne treatment. However, studies comparing their efficacies are rare. Aim: To evaluate the clinical and in vivo antibacterial effect of lymecycline and minocycline at different dosages. Method: Eighty-six patients with moderate to severe acne were enrolled in a randomized, double-blind, intent-to-treat study comparing in three parallel groups the effect of (1) lymecycline 300 mg daily for 12 weeks, (2) minocycline 50 mg daily for 12 weeks and (3) minocycline 100 mg daily for 4 weeks followed by 50 mg daily for 8 weeks. Evaluations were made at the screening visit and at five on-treatment visits. They consisted of clinical counts of acne lesions and evaluations of bacterial viability using dual flow cytometry performed on microorganisms collected from sebaceous infundibula by cyanoacrylate strippings. Results: Patients receiving minocycline 100/50 mg had the best clinical outcome, particularly in the reduction of the number of papules. By the end of the trial, the microbial response to minocycline 100/ 50 mg was also superior to either of the other two treatments. There were less live and more dead bacteria. Conclusion: In this trial, minocycline 100/50 mg was superior for the treatment of inflammatory acne when compared to lymecycline 300 mg and minocycline 50 mg.

Influence of topical tretinoin on skin lipid production in vivo.

Topical application of tretinoin induces skin changes characterized by erythema, dryness and desquamation. These changes are primarily due to a specific tretinoin action on keratinocyte differentiation and proliferation [1]. Tretinoin added to cultured keratinocytes is able to impair morphological structure and the expression of several markers of terminal differentiation such as filaggrin, loricrin and involucrin [2]. The reduction in the expression of these proteins is considered to be the cause of a reduced and less adhesive horny layer [3]. Interlamellar lipids also play an important role in lamellar cohesion and adhesion in the stratum corneum layers [4]. However, little information is available on the effects of retinoic acid (RA) on interlamellar lipid synthesis [5]. The synthesis of these specific lipids is a part of keratinocyte differentiation [6], so theoretically tretinoin may also affect keratinocyte lipid metabolism. The aim of this study was to verify in vivo whether the topical application of tretinoin induces any modification in lipid production. For this purpose lipids from cyanoacrylate strippings of the horny layer after 21 days tretinoin exposure were analysed and compared with those from a vehicle-treated area of the same subject. Stratum corneum samples were obtained from the volar forearm of ten healthy volunteers, all females (ages ranging from 28 to 35 years), treated with freshly prepared tretinoin (all-trans-RA) 0.05%, glycoalcoholic solution, once a day, Monday to Friday, for a period of 21 days (15 applications). The contralateral forearm was treated with vehicle (propylene glycol/ethanol, 1:1) as control. The clinical score was recorded 2 days after the final application, and transepidermal water loss (TEWL) was measured by means of an evaporimeter (EP1, Servomed, Stockholm, Sweden). Stratum corneum samples were obtained by a single

Ceramide and cholesterol composition of the skin of patients with atopic dermatitis.

Atopic dermatitis skin tends to be easily irritated and appears dry. These clinical peculiarities correspond to impaired barrier function and to increased transepidermal water loss (TEWL) values. A few studies suggest that a reduced amount of total ceramides (especially of ceramide 1) is responsible for functional abnormalities of the skin of atopic dermatitis patients. The aim of this study was to analyze the relationship between epidermal lipids and barrier impairment in the skin of patients with atopic dermatitis. The quantity of ceramides, cholesterol sulphate and free cholesterol of 47 patients with atopic dermatitis and 20 age- and sex-matched healthy subjects was assessed by cyanoacrylate stripping and thin layer chromatography. Capacitance and TEWL were recorded at the same site of the lipid sample. In patients with atopic dermatitis, the levels of ceramide 1 and 3 were significantly lower and values of cholesterol significantly higher with respect to healthy subjects. Moreover, the CER/CH ratio was significantly lower with respect to normal skin. Patients with active signs of eczema also had higher TEWL values and lower capacitance values. By contrast, patients with no active signs of atopic dermatitis had a normal barrier function and intermediate values of ceramides and cholesterols, when compared to patients with atopic dermatitis with active lesions and normal subjects. The quantity of ceramide 3 was significantly correlated with TEWL impairment. These findings suggest that a decrease in ceramides in the stratum corneum is involved in barrier impairment in atopic dermatitis skin. Our data confirm those of other authors and support the view that impaired metabolism of ceramides may be the cause of dry skin and impaired barrier function in atopic dermatitis.

Improved method for studying skin lipid samples from cyanoacrylate strips by high-performance thin-layer chromatography.

A non-invasive method for sampling skin surface lipids is cyanoacrylate stripping (CAC-TS). It was the purpose of our study to improve the method for sampling of skin surface lipids and the separation of epidermal lipid fractions by a modification of the methods described by Melnik and by Imokawa et al. Briefly, lipids on the glass slide sampled by CAC-TS from the forearm of 75 volunteers and from the forehead of 60 volunteers were eluted in hexane/ethanol under ultrasonication. Identification of the diluted total superficial sebaceous and epidermal skin lipids was performed by sequential high-performance thin-layer chromatography. For quantification of the lipids we used densitometric methods. By this modified method we were able to show a clear and complete separation of all relevant lipids from a cyanoacrylate strip that represented 1-2 mg stratum corneum only.