Increased mass levels of certain serine proteases in the stratum corneum in acute eczematous atopic skin.

Acute eczematous atopic dermatitis (AD) is associated with increases in stratum corneum (SC) serine protease activity. The purpose of this study was to examine whether the increased SC protease activities in acute eczematous atopic dermatitis were associated with increased mass levels of SC proteases. Six subjects with healthy skin and six patients with AD each with non-lesional skin or lesional acute eczematous skin had the mass levels of their extractable SC kallikreins (KLK), plasmin and urokinase quantified using Luminex multiplex bead-based assays from SC tape strippings. The mass levels of KLK5 and KLK14 together with urokinase were not elevated in the SC in atopic skin. However, the mass levels of KLK7 and KLK11 together with plasmin were greatly elevated compared with the extracts from the non-lesional and the healthy skin and correlated with the corresponding enzymatic activities.

Increased stratum corneum serine protease activity in acute eczematous atopic skin.

BACKGROUND: Atopic dermatitis (AD) is a chronic inflammatory disease associated with changes in stratum corneum (SC) structure and function. The breakdown of epidermal barrier function in AD is associated with changes in corneocyte size and maturation, desquamation, lipid profiles, and some protease activities. OBJECTIVES: The purpose of this study was: (i) to examine physiological changes in lesional (L) skin of acute eczematous AD, compared with nonlesional (NL) AD skin and healthy (H) skin, using sequential tewametry and SC protein analysis to estimate SC thickness; and (ii) to assess which serine proteases might be involved in pathogenesis. METHODS: Six subjects with H skin, six AD patients with NL skin and six AD patients with mild to moderate eczema (L skin) were enrolled. Skin was assessed using several noninvasive techniques but SC thickness was estimated using tewametry and SC protein content of D-Squame strippings. SC integrity was determined by sequential tape stripping (D-Squame) and infrared densitometry. Kallikreins, plasmin, urokinase and leucocyte elastase protease activities together with a novel SC tryptase-like enzyme activity were quantified. RESULTS: Transepidermal water loss (TEWL) levels after D-Squame stripping were elevated in L compared with NL and H skin at all sampling points (P < 0.05). Conversely, the amount of SC removed by sequential tape stripping was decreased in L skin, indicating increased intracorneocyte cohesion (P < 0.05). By correlating 1/TEWL values and SC removed as an estimate of SC thickness, a significantly thinner SC was observed in L compared with NL and H skin (P < 0.05). Elevated extractable serine protease activity was measured in AD skin in the order: SC tryptase-like enzyme (45x), plasmin (30x), urokinase (7.1x), trypsin-like kallikreins (5.8x) and chymotrypsin-like kallikreins (3.9x). Leucocyte elastase activity was not detected in H and NL skin but was observed in AD SC samples (L skin). All enzymes were elevated in the deeper layers of L SC compared with NL and H SC samples. All consistently elevated SC protease activities were significantly correlated with the bioinstrumental data. CONCLUSIONS: We report increased serine protease activities in acute eczematous AD, especially in deeper layers of the SC, including SC tryptase-like enzyme, plasmin, urokinase and leucocyte elastase activities. These elevations in protease activities were associated with impaired barrier function, irritation, and reduced skin capacitance. Increased SC cohesion was apparent despite elevated TEWL during tape stripping, which would indicate reduced SC thickness in acute eczematous lesions of AD. Indeed, this was observed using an estimate of SC thickness.

Placebo-controlled, double-blind, randomized, prospective study of a glycerol-based emollient on eczematous skin in atopic dermatitis: biophysical and clinical evaluation.

BACKGROUND/AIMS: Atopic dermatitis (AD) is a frequent, chronic inflammatory disease influenced by local, immunological, genetic and environmental factors. Important symptoms of AD are dry skin, intense pruritus and impaired epidermal barrier function. The therapeutic management of AD is difficult and needs individualized concepts. Moisturizing creams and emollients are useful and important treatment adjuncts for the daily skin care of patients with dry and inflamed skin, e.g. AD. Glycerol is known to increase stratum corneum (SC) hydration, improve epidermal barrier function and decrease clinical signs of inflammation. However, no controlled study on the efficacy of glycerol on barrier function and SC hydration in AD has been published. In the present study, a topical 20% glycerol preparation was compared with its vehicle in patients with AD. The aim of the present study was to evaluate the effect of a single emollient ingredient in AD within the full frame of a phase III drug study. METHODS: 24 patients with AD were treated for 4 weeks twice daily with a glycerol-based emollient in a randomized, double-blind study. Transepidermal water loss, skin capacitance, erythema and skin surface pH were assessed with biophysical, non-invasive instruments. The SCORAD and a local severity score were evaluated. After a wash-out period of 2 weeks, these parameters were assessed in order to quantify the sustained effect of this treatment. RESULTS: SC hydration was significantly improved, and epidermal barrier function was restored under treatment with glycerol-containing cream compared to the glycerol-free placebo. No significant differences were detectable for erythema values, SCORAD and local severity between the glycerol-containing cream and placebo. However, an improvement over time was detectable in the assessed parameters in both groups indicating the importance of emollient treatment in AD. CONCLUSIONS: Glycerol-based emollients have a positive influence on the skin of patients with AD. They enhance the SC hydration. Furthermore, it was possible to evaluate skin care products with a protocol design for efficacy studies of fully registered drugs in a placebo-controlled study.

Acute barrier disruption by adhesive tapes is influenced by pressure, time and anatomical location: integrity and cohesion assessed by sequential tape stripping. A randomized, controlled study.

BACKGROUND: Tape stripping is an established procedure in stratum corneum (SC) physiology research. Adhesive films are pressed to the surface of the skin and then removed. The superficial layers of the SC adhere to the film and are accessible for further investigations. Although this method is widely used, only scant information about standardization is known. Various protocols are used but are difficult to compare. OBJECTIVES: The aim of the present study was to investigate the effects of the type of tape, pressure, time, anatomical site and type of applied pressure. METHODS: Twelve healthy volunteers (age range 20-31 years) were entered in a randomized, controlled study with sequential tape stripping at the volar forearm, upper arm, cheek and back. Different methods (roller, stamp, thumb, stretched skin), total duration of applied pressure (2 s, 10 s), degrees of pressure (2 N stamp, 7 N stamp) and different tapes (D-Squame, Corneofix, Blenderm) were investigated and the impact on barrier function assessed by transepidermal water loss measurements. Furthermore, measurements of SC hydration, skin colour and skin surface pH were performed. Spectroscopic measurements and a Bradford protein assay to determine the mass of removed SC were carried out in parallel. RESULTS: The degree of barrier disruption, irritation and SC cohesion is influenced by the character of adhesive tapes, total duration of applied pressure (2 s, 10 s; 2 N, 7 N), the kind of method for pressure application (roller, stamp, thumb, stretched skin), anatomical site and condition before stripping (occlusion vs. nonocclusion). The spectroscopic assessment and Bradford protein assay determination showed a significant correlation (P < 0.0001; r = 0.7041). CONCLUSIONS: The present study showed significant differences between different factors on controlled barrier disruption. The results indicate the importance of defining these factors when a study is initiated and when results of different studies should be compared. Based on our data we propose using a 2 N stamp for a duration of 2 s on 15 sequential D-Squame tape strips on the volar forearm and then discarding the first and second strips. This approach allows the performance of a standardized study with a reasonable amount of resources.