Penetration and biological effects of topically applied cyclosporin A nanoparticles in a human skin organ culture inflammatory model.

Systemic antipsoriatic therapies have potentially life-threatening, long-term side effects. The efficacy of topical drugs is poor, but may be improved by the use of delivery systems based on drug nanoparticles. To produce nanoparticles (NP) composed of cyclosporin A, a classical antipsoriatic drug, and to investigate their penetration and biological effects in human skin affected by psoriatic symptoms, poly-ε-caprolactone (PCL) and cyclosporin A (CsA) NP were prepared by the solvent evaporation method.

Evaluation of topically applied copper(II) oxide nanoparticle cytotoxicity in human skin organ culture.

The increasing use of nano-sized materials in our environment, and in many consumer products, dictates new safety concerns. In particular, adequate experimental models are needed to evaluate skin toxicity of metal oxide ions, commonly found in cosmetic and dermatologic preparations. We have addressed the biological effects of topically applied copper oxide (CuO) nanoparticles in human skin organ cultures, using light and electron microscopy, and biochemical tests.

Photo-damage protective effect of two facial products, containing a unique complex of Dead Sea minerals and Himalayan actives.

Background: Skin appearance is badly affected when exposed to solar UV rays, which encourage physiological and structural cutaneous alterations that eventually lead to skin photo-damage.

Aims: To test the capability of two facial preparations, extreme day cream (EXD) and extreme night treatment (EXN), containing a unique complex of Dead Sea water and three Himalayan extracts, to antagonize biological effects induced by photo-damage.

Methods: Pieces of organ cultures of human skin were used as a model to assess the biological effects of UVB irradiation and the protective effect of topical application of two Extreme preparations.

Isothiocyanates inhibit psoriasis-related proinflammatory factors in human skin.

Objective: 4-Methylthiobutylisothiocyanate (MTBI), the main rocket (Eruca sativa) seed isothiocyanate (ITC), and its oxidized form, sulforaphane (SFN), were assessed for their potential effects on psoriasis-related factors.

Methods: MTBI and SFN were evaluated for their effect on mRNA expression and cytokine secretion in vitro in human monocytes and macrophage-like cells and ex vivo in topically treated inflamed human skin. In addition, they were assayed in vivo for morphological changes in topically treated psoriasiform human skin in severe-combined immunodeficient (SCID) mice.

Non-invasive skin biomarkers quantification of psoriasis and atopic dermatitis: cytokines, antioxidants and psoriatic skin auto-fluorescence.

Background: Psoriasis and atopic dermatitis (AD) are challenging to treat due to the absence of suitable monitoring procedure and their recurrences. Alteration of skin hydrophilic biomarkers (SHB) and structural elements occur in both disorders and may possess a distinct profile for each clinical condition.

Objective: To quantify skin cytokines and antioxidants non-invasively in psoriatic and in AD patients and to evaluate skin auto-fluorescence in psoriatic patients.

Skin organ culture as a model to study oxidative stress, inflammation and structural alterations associated with UVB-induced photodamage.

Background: Ultraviolet (UV) irradiation is a major cause of skin damage, of long-term alteration of skin metabolism, homoeostasis and physical structure. The analysis of UV-induced pathogenic processes requires in vitro models allowing biochemical studies, and appropriate for the development of novel, accurate diagnosis methods based on non-invasive procedures.

Objectives: This work was aimed to reproduce the effects of UVB on whole-skin explants ex vivo and to study underlying biochemical mechanisms, especially in correlation with skin autofluorescence.

Apoptolysis: a novel mechanism of skin blistering in pemphigus vulgaris linking the apoptotic pathways to basal cell shrinkage and suprabasal acantholysis.

Understanding the acantholytic pathways leading to blistering in pemphigus vulgaris (PV) is a key to development of novel treatments. A novel paradigm of keratinocyte damage in PV, termed apoptolysis, links the suprabasal acantholytic and cell death pathways to basal cell shrinkage rendering a 'tombstone' appearance to PV lesions. In contrast to apoptolysis, the classic keratinocyte apoptosis mediating toxic epidermal necrolysis causes death and subsequent sloughing of the entire epidermis.

Protective effects of a cream containing Dead Sea minerals against UVB-induced stress in human skin.

Background: Dead Sea (DS) mud and water are known for their unique composition of minerals, and for their therapeutic properties on psoriasis and other inflammatory skin diseases. Their mode of action, however, remains poorly known.

Objectives: To analyse the ability of Dermud, a leave-on skin preparation containing DS mud and other ingredients like DS water, zinc oxide, aloe-vera extract, pro-vitamin B5 and vitamin E, to antagonize biological effects induced by UVB irradiation in skin when topically applied in organ cultures.

Aged keratinocyte phenotyping: morphology, biochemical markers and effects of Dead Sea minerals.

The aging process and its characterization in keratinocytes have not been studied in depth until now. We have assessed the cellular and molecular characteristics of aged epidermal keratinocytes in monolayer cultures and in skin by measuring their morphological, fluorometric and biochemical properties. Light and electron microscopy, as well as flow cytometry, revealed increase in cell size, changes in cell shape, alterations in mitochondrial structure and cytoplasmic content with aging.

Method for chronological recording of antigen appearance in human head-hair shafts and its use for monitoring glycation products in diabetes.

We describe immunochemical assays of non-enzymatic glycation products in human head-hair protein extracts and hair cross sections using Western blots and a novel "dot-block" methodology. In the latter, groups of approximately 15 hair fibers, clipped at about 1 mm proximal to the scalp-skin were aligned, wound around, and attached to 3 mm diameter araldite screw rods. Up to 40 such rods were next embedded lengthwise in additional araldite polymer creating a solid block and the top surface of the block was sectioned off to the half-diameters of the screw rods thus exposing accurately transected hair cross sections at regular ( approximately 0.

Apoptotic mechanism in pemphigus autoimmunoglobulins-induced acantholysis--possible involvement of the EGF receptor.

Pemphigus is an autoimmune cutaneous disease characterized by circulating autoantibodies that cause blistering and erosions on skin and mucous membranes. Circulating autoantibodies bind to epidermal cell membrane and cause cell-cell detachment (acantholysis), leading to epidermal tissue damage and cell death. The principal target of pemphigus vulgaris autoantibodies (PV-IgG) is desmosomal cadherin desmoglein 3 (Dsg3), a constituent of desmosomes, mediating cell-cell adhesion.

The ubiquitin-proteasome system at the crossroads of stress-response and ageing pathways: a handle for skin care?

The regulation of gene expression at the transcriptional level has been considered for long as the main mechanism of cellular adaptive responses. Since the turn of the century, however, it is becoming clear that higher organisms developed a complex, sensitive and maybe equally important network of regulatory pathways, relying largely on protein interactions, post-translational modifications and proteolysis. Here we review the involvement of the ubiquitin-proteasome pathway of protein degradation at different levels of cellular life in relation with ageing, and with a special focus on skin.

The interaction of pemphigus autoimmunoglobulins with epidermal cells: activation of the fas apoptotic pathway and the use of caspase activity for pathogenicity tests of pemphigus patients.

Pemphigus is a fatal autoimmune disease in which autoimmunoglobulins PV-IgG (binding to desmoglein 3) and PF-IgG (binding to desmoglein 1) in pemphigus vulgaris and pemphigus foliaceus, respectively, cause intraepidermal blisters, cell-cell separation (acantholysis), and cell death. The mechanism of acantholytic lesion formation has not yet been elucidated. Recently, we have reported that an apoptotic mechanism might be operative in PV-IgG-induced acantholysis: (1) in patients' lesional and some perilesional skin portions, the FasR pathway is activated as its components were enriched; (2) in cultured keratinocytes, PV-IgG upregulates effectors of the FasR pathway (including the mitochondrial loop), as found by immunodetermination (cytochemistry, Western blot of pathway effectors) and determination of caspases 1, 3, and 8 activity/activation; (3) in organ cultures of skin incubated with PV-IgG, activated caspase 8 was found also in perilesional cells and coaggregated with bound PV-IgG; (4) caspase 8 activation in DISCs precedes caspase 3 activation in keratinocytes in cultures upon incubation with PV-IgG.

Replicative senescence enhances apoptosis induced by pemphigus autoimmune antibodies in human keratinocytes.

We have recently shown that skin lesions of the autoimmune disease pemphigus vulgaris are associated with Fas-mediated apoptosis. Here, we describe the induction of the Fas-dependent apoptosis pathway in cultured keratinocytes by pemphigus vulgaris autoantibodies (PV-IgG), as seen from a variety of cellular, morphological and biochemical parameters. All apoptotic characters appear stronger and faster in aged cultures than in young, showing increased susceptibility of senescent keratinocytes to PV-IgG-mediated apoptotic death and culture lesions.

Enhancement of Fas-mediated apoptosis in ageing human keratinocytes.

Cellular senescence and apoptosis are two metabolically related and seemingly synergistic processes that are involved in tissue maintenance and homeostasis, anti-tumor protection, and age-related diseases. Despite this apparent co-operativity, senescence can inhibit apoptosis in certain conditions. Here, we describe senescence-apoptosis relationships in human epidermal cells by comparing apoptosis-related effector concentrations in keratinocyte cultures and epidermal skin cells at various stages of ageing.

Cellular senescence in human keratinocytes: unchanged proteolytic capacity and increased protein load.

In order to assess the activity of cellular proteasome, we developed a method to permeabilize keratinocyte monolayers and measure proteasome activities intracellularly, using fluorogenic peptide substrates. The observed K(m) did not differ significantly in situ and in soluble extracts, and the K(i) of proteasome inhibitor MG132 was slightly higher in situ (34nM instead of 4nM). Inhibition studies in permeabilized cells showed that MG132 followed competitive inhibition patterns, and clasto-lactacystin beta-lactone non-competitive patterns, as expected.

Exogen, shedding phase of the hair growth cycle: characterization of a mouse model.

The hair growth cycle is generally recognized to comprise phases of growth (anagen), regression (catagen), and rest (telogen). Whereas, heretofore, the hair shedding function has been assumed to be part of the telogen phase, using a laboratory mouse model and newly developed techniques for quantitative collection and spectroscopic determination of shed hair, we found that shedding actually occurs as a distinct phase. Although some shedding occurs throughout the growth cycle, the largest peak is coupled to anagen.