Hydrolytic pathway protects against ceramide-induced apoptosis in keratinocytes exposed to UVB.

Although ceramides (Cers) are key constituents of the epidermal permeability barrier, they also function as apoptogenic signals for UVB irradiation-induced apoptosis in epidermal keratinocytes. As epidermis is continuously exposed to UV irradiation, we hypothesized that Cer hydrolysis protects keratinocytes from UVB-induced apoptosis by attenuating Cer levels. Both low-dose UVB (L-UVB) (< 35 mJ cm(-2)) and high-dose UVB (H-UVB) (> or = 45 mJ cm(-2)) irradiation inhibited DNA synthesis in cultured human keratinocytes, but apoptosis occurred only after H-UVB.

Clinical scoring and biophysical evaluation of nasolabial skin barrier damage caused by rhinorrhea.

Background: An acute viral cold is a very common illness and is characterized by sneezing and a runny nose. Because of rhinorrhea and frequent use of handkerchiefs, the skin around the nose feels uncomfortably dry and flaky.

Objectives/methods: To evaluate the nasolabial skin barrier impairment, 14 female volunteers with a common cold were recruited.

Effects of lotioned disposable handkerchiefs on skin barrier recovery after tape stripping.

Background/purpose: In the present work, it was studied whether repeated use of lotioned disposable handkerchiefs on tape-stripped forearm skin was able to improve skin barrier recovery.

Methods: Skin assessments included scoring of visual erythema and dryness/scaliness; and measuring of skin redness (Chromameter CR300), skin hydration (Corneometer CM825), and transepidermal water loss (Tewameter TM300). Four different lotioned paper handkerchiefs - randomly assigned to one of two subject groups (n=20) - were tested vs.

Acute modulations in permeability barrier function regulate epidermal cornification: role of caspase-14 and the protease-activated receptor type 2.

Stratum corneum comprises corneocytes, derived from outer stratum granulosum during terminal differentiation, embedded in a lipid-enriched extracellular matrix, secreted from epidermal lamellar bodies. Permeability barrier insults stimulate rapid secretion of preformed lamellar bodies from the outer stratum granulosum, regulated through modulations in ionic gradients and serine protease (SP)/protease-activated receptor type 2 (PAR2) signaling. Because corneocytes are also required for barrier function, we hypothesized that corneocyte formation could also be regulated by barrier function.

Serine protease signaling of epidermal permeability barrier homeostasis.

Evidence is growing that protease-activated receptor-2 (PAR-2) plays a key role in epithelial inflammation. We hypothesized here that PAR-2 plays a central role in epidermal permeability barrier homeostasis by mediating signaling from serine proteases (SP) in the stratum corneum (SC). Since the SC contains tryptic- and chymotryptic-like activity, we assessed the influence of SP activation/inhibition on barrier function.

Skin condition associated with intensive use of alcoholic gels for hand disinfection: a combination of biophysical and sensorial data.

Although hand hygiene is an important and inexpensive measure to prevent nosocomial infections in clinical settings, the compliance of healthcare workers remains low. In Europe, alcoholic hand disinfection is first choice, but there exists a limited user acceptability due to estimated adverse effects on skin condition. This study was designed to investigate skin tolerance to alcohol-based disinfecting gels and changes in skin condition depending on humectant concentration, alcohol grades, as well as type of alcohol used.

Serine protease activity and residual LEKTI expression determine phenotype in Netherton syndrome.

Mutations in the SPINK5 gene encoding the serine protease (SP) inhibitor, lymphoepithelial-Kazal-type 5 inhibitor (LEKTI), cause Netherton syndrome (NS), a life-threatening disease, owing to proteolysis of the stratum corneum (SC). We assessed here the basis for phenotypic variations in nine patients with "mild", "moderate", and "severe" NS. The magnitude of SP activation correlated with both the barrier defect and clinical severity, and inversely with residual LEKTI expression.

Differentiation-associated expression of ceramidase isoforms in cultured keratinocytes and epidermis.

Ceramides (Cers) accumulate within the interstices of the outermost epidermal layers, or stratum corneum (SC), where they represent critical components of the epidermal permeability barrier. Although the SC contains substantial sphingol, indicative of ceramidase (CDase) activity, which CDase isoforms are expressed in epidermis remains unresolved. We hypothesized here that CDase isoforms are expressed within specific epidermal compartments in relation to functions that localize to these layers.

Validation of the VapoMeter, a closed unventilated chamber system to assess transepidermal water loss vs. the open chamber Tewameter.

Background/aim: Transepidermal water loss (TEWL) is one of the most important biophysical parameters for evaluating the efficiency of the human skin water barrier. Different approaches exist to measure TEWL. The most commonly used methodology consists of the open chamber diffusion technique in which the water vapor pressure gradient is measured in g/h m2 according to Fick's law.