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Barrier creams to protect diseased skin
Workshop WIO. Permeability in healthy and diseased skin gene mutations. We investigated the regulation of NFI gene expression in melanocytes. Incubation with PMA or bFGF increases the neurofibromin content in cultured melanocytes of controls by posttranslational mechanisms influencing the degradation rate of the protein. In unstimulated melanocytes the neurofibromin half-life was estimated at about 27 hrs. The addition of PMA prolonged the half-life to a mean 7 1 hrs. The neurotibromin half-life in melanocytes of NFl patients (skin or cafe au fait macu-le) does not differ clearly in this respect. As shown in experiments with okadaic acid and chloroquine, a phos-phorylation of neurofibromin and its lysosomal uptake play important roles in the degradation of neurofibromin. In addition, the expression the EVIZB-gene lying in intron 27 of the NFl gene was investigated. Like neurofibromin it is expressed during the differentiation of keratinocytes by high calcium.
WlO.
Permeability in healthy and diseased SkiIl
WIO-1
Skin barrier-ultrastructure diseased skin
in healthy
and
M. Fartasch. Dept. of Dermatology, University of Erlangen, Erlaugen, Gennany The water permeability barrier of the stratum comeum (SC) seems primarily to be regulated by the lamellarly arranged lipid bilayers between the comeocytes, which originate largely from polar lipid precursors provided by the cells of stratum granulosum via exocytosis of the lamellar body content. In particular, the structural organization of these intercellular lipid lamellae seems to be responsible for the very low water permeability of the intact skin. Changes of biophysical properties of the SC, especially of the water-permeability barrier, appear in a variety of diseases of different etiology and have implications on the pathogenesis and course of skin diseases (e.g., psoriasis, atopic dermatitis, ichthyoses). All these diseases are clinically characterized by a dry, scaly skin condition. In this review the distribution and organization of the epidermal lipids in normal human skin and scaling skin disorders are analyzed. WlO-2
Metabolism during molecular healthy and diseased skin
transfer
in
H. Merk, J. Baron, Th. Roos, E Jugert. Dep. of Dermatology, RWTH Aachen, Germany The metabolism of small molecular weight compounds such as drugs, pollutants contact antigens are often metabolized by enzymes such as cytochrome P450 (CYP) isoenzymes which therefore may play a role as second barrier after the first barrier of the stratum comeum. They are able to metabolize endogenous compounds especially such as retinoids, vitamin D derivates or ceramids which play a role in cell differentiation processes. Recently we wanted to assess the difference the differences in CYP-expression in cells isolated from various compartments of the human skin. RT-PCR was used as a screening method for the detection of CYP-isoenzyme expression in the target Cells. RT-PCR-results were confirmed afterwards by means northern-blot, immunoblot, immunostaining and catalytic as-
s75
says. Keratinocytes derived from the human epidermis revealed an expression of CYP lA1, lB1, 2B1, 2B6, 2El and 3A. Antigen presenting cells such as monocytes and macrophages demonstrated the constitutive expression of CYPlAl and 3A4/5 only after incubation with known CYP inducers. Recent data with regard to CYP26 which metabolises all-transretinoic acid showed different expression patterns in fibroblasts, keratinocytes and the in vivo versus in vitro situation, which underlines different influences of cell differentiation levels. I WI0 3 Barrier creams to protect diseased skin P. Elsner, W. Wigger-Alberti. Dept. of Dermatology, Friedrich Miller University, Jena, Germany Contact dermatitis is the most frequent manifestation of occupational skin disease. Since the course may be chronic leading to disability, and since treatment is frequently of limited efficacy, prevention should have priority to reduce the incidence and prevalence of irritant contact dermatitis (ICD) and allergic contact dermatitis (ACD). Barrier creams may be important tools in an integrated concept of preventive measures. Since Suskind introduced the ‘slide test’ to evaluate barrier creams in the 1950s various in vitro techniques and in vivo tests on animals or human skin were developed to investigate the efficacy of barrier creams as pre-exposure skin protectors. Our group has worked on the optimization of the repeated irritation test (RIT) as proposed by Frosch and Kurte. Recent data showing the efficacy of protective creams wilI be reported. Studies using fluorescence-marked creams have shown that while products may be effective, they are frequently applied in an unsatisfactory manner. Strategies to improve the application and the compliance of workers will be presented. WIO-4
Permeability
in healthy
and diseased
skin
Peter M. Elias. Dermatology Service, V’C and Department of Dermatology, University of California, San Francisco, CA, USA The most important function of the skin is provision of a permeability barrier the stratum comeum (SC), which allows life in a terrestrial environment. The structure of this barrier is a unique two-component system of lipid-depleted comeocytes embedded in a multi-lamellar, lipids-enriched extracellular ma&ix. Formation of this matrix is a multi-step sequence, beginning with the synthesis of the three SC lipids, cholesterol. ceramides, and fatty acids. This is followed by packaging of these lipids as their precursors, along with lipid catabolic enzymes, within Iamellar bodies. The next steps are: (a) secretion of lame&-u body contents; and (b) extracellular processing of secreted lipid precursors by colocalized hydrolitic enzymes leading to barrier formation. Each step of this sequence is tightly regulated by alterations in barrier requirements allowing for rapid restoration of barrier homeostasis after most types of acute perturbation. The regulatory signals that link the SC with the nucleated layers, thereby driving the epidermal metabolic apparatus, are beginning to be characterized. For example, alterations *in extracellular divalent cations and other ions, resulting ‘from loss during barrier perturbations, regulate lame&u body secretion from the outermost granular cells. Whereas cytokine and
WlO.
Permeability in healthy and diseased SkiIl
WIO-1
Skin barrier-ultrastructure diseased skin
in healthy
and
M. Fartasch. Dept. of Dermatology, University of Erlangen, Erlaugen, Gennany The water permeability barrier of the stratum comeum (SC) seems primarily to be regulated by the lamellarly arranged lipid bilayers between the comeocytes, which originate largely from polar lipid precursors provided by the cells of stratum granulosum via exocytosis of the lamellar body content. In particular, the structural organization of these intercellular lipid lamellae seems to be responsible for the very low water permeability of the intact skin. Changes of biophysical properties of the SC, especially of the water-permeability barrier, appear in a variety of diseases of different etiology and have implications on the pathogenesis and course of skin diseases (e.g., psoriasis, atopic dermatitis, ichthyoses). All these diseases are clinically characterized by a dry, scaly skin condition. In this review the distribution and organization of the epidermal lipids in normal human skin and scaling skin disorders are analyzed. WlO-2
Metabolism during molecular healthy and diseased skin
transfer
in
H. Merk, J. Baron, Th. Roos, E Jugert. Dep. of Dermatology, RWTH Aachen, Germany The metabolism of small molecular weight compounds such as drugs, pollutants contact antigens are often metabolized by enzymes such as cytochrome P450 (CYP) isoenzymes which therefore may play a role as second barrier after the first barrier of the stratum comeum. They are able to metabolize endogenous compounds especially such as retinoids, vitamin D derivates or ceramids which play a role in cell differentiation processes. Recently we wanted to assess the difference the differences in CYP-expression in cells isolated from various compartments of the human skin. RT-PCR was used as a screening method for the detection of CYP-isoenzyme expression in the target Cells. RT-PCR-results were confirmed afterwards by means northern-blot, immunoblot, immunostaining and catalytic as-
s75
says. Keratinocytes derived from the human epidermis revealed an expression of CYP lA1, lB1, 2B1, 2B6, 2El and 3A. Antigen presenting cells such as monocytes and macrophages demonstrated the constitutive expression of CYPlAl and 3A4/5 only after incubation with known CYP inducers. Recent data with regard to CYP26 which metabolises all-transretinoic acid showed different expression patterns in fibroblasts, keratinocytes and the in vivo versus in vitro situation, which underlines different influences of cell differentiation levels. I WI0 3 Barrier creams to protect diseased skin P. Elsner, W. Wigger-Alberti. Dept. of Dermatology, Friedrich Miller University, Jena, Germany Contact dermatitis is the most frequent manifestation of occupational skin disease. Since the course may be chronic leading to disability, and since treatment is frequently of limited efficacy, prevention should have priority to reduce the incidence and prevalence of irritant contact dermatitis (ICD) and allergic contact dermatitis (ACD). Barrier creams may be important tools in an integrated concept of preventive measures. Since Suskind introduced the ‘slide test’ to evaluate barrier creams in the 1950s various in vitro techniques and in vivo tests on animals or human skin were developed to investigate the efficacy of barrier creams as pre-exposure skin protectors. Our group has worked on the optimization of the repeated irritation test (RIT) as proposed by Frosch and Kurte. Recent data showing the efficacy of protective creams wilI be reported. Studies using fluorescence-marked creams have shown that while products may be effective, they are frequently applied in an unsatisfactory manner. Strategies to improve the application and the compliance of workers will be presented. WIO-4
Permeability
in healthy
and diseased
skin
Peter M. Elias. Dermatology Service, V’C and Department of Dermatology, University of California, San Francisco, CA, USA The most important function of the skin is provision of a permeability barrier the stratum comeum (SC), which allows life in a terrestrial environment. The structure of this barrier is a unique two-component system of lipid-depleted comeocytes embedded in a multi-lamellar, lipids-enriched extracellular ma&ix. Formation of this matrix is a multi-step sequence, beginning with the synthesis of the three SC lipids, cholesterol. ceramides, and fatty acids. This is followed by packaging of these lipids as their precursors, along with lipid catabolic enzymes, within Iamellar bodies. The next steps are: (a) secretion of lame&-u body contents; and (b) extracellular processing of secreted lipid precursors by colocalized hydrolitic enzymes leading to barrier formation. Each step of this sequence is tightly regulated by alterations in barrier requirements allowing for rapid restoration of barrier homeostasis after most types of acute perturbation. The regulatory signals that link the SC with the nucleated layers, thereby driving the epidermal metabolic apparatus, are beginning to be characterized. For example, alterations *in extracellular divalent cations and other ions, resulting ‘from loss during barrier perturbations, regulate lame&u body secretion from the outermost granular cells. Whereas cytokine and