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Biomedical subjects

P Arenberger

Publications and source records attributed to P Arenberger.

At least 19 recordsLinked to original sources
PubMed2004

Towards optimization of an organotypic assay system that imitates human hair follicle-like epithelial-mesenchymal interactions.

BACKGROUND: Human hair growth can currently be studied in vitro by the use of organ-cultured scalp hair follicles (HFs). However, simplified organotypic systems are needed for dissecting the underlying epithelial-mesenchymal interactions and as screening tools for candidate hair growth-modulatory agents. OBJECTIVES: To optimize the design and culture conditions of previously published organotypic systems that imitate epithelial-mesenchymal interactions in the human HF as closely as possible. MATERIALS AND METHODS: Continuous submerged organotypic 'sandwich' cultures were established. These consist of a pseudodermis (collagen I mixed with and contracted by human interfollicular dermal fibroblasts) on which one of two upper layers is placed: either a mixture of Matrigel basement membrane matrix (BD Biosciences, Bedford, MA, U.S.A.) and follicular dermal papilla fibroblasts (DPC), with outer root sheath keratinocytes (ORSK) layered on the top ('layered' system), or a mixture of Matrigel, DPC and ORSK ('mixed' system). Morphological and functional characteristics of these 'folliculoid sandwiches' were then assessed by routine histology, histomorphometry and immunohistochemistry. RESULTS: In both 'layered' and 'mixed' systems, the ORSK formed spheroid epithelial cell aggregates, which retained their characteristic keratin expression pattern (i.e. cytokeratin 6). In the 'mixed' sandwich model the size of the epithelial cell aggregates was smaller, but the numbers of ORSK were significantly higher than in the 'layered' model at day 14 in the culture. ORSK proliferated better in the 'mixed' than in the 'layered' sandwich system, regardless of the calcium or serum content of the media, whereas apoptosis of ORSK was lowest in the 'mixed' system in serum-free, low calcium medium. The kinetics of proliferation and apoptosis of DPC, which retained their characteristic expression of versican, were similar in both systems. However, proliferation and apoptosis of DPC were higher in the presence of serum and/or under high calcium conditions. CONCLUSIONS: Our results underscore the importance of structural design and medium composition for epithelial-mesenchymal interactions as they occur in the human HF. Specifically, we report a new organotypic submerged 'folliculoid sandwich' system with serum-free, low calcium medium and a mixture of interacting human DPC and ORSK, which offers several advantages over previously available assays. This system allows the standardized assessment of the effects of a test agent on the proliferation, apoptosis and key marker expression of human ORSK and DPC under substantially simplified in vitro conditions which approximate the in vivo situation.

Apoptosis↗
PubMed2004

Gene expression in actinic keratoses: pharmacological modulation by imiquimod.

BACKGROUND: Actinic keratoses (AKs) are premalignant lesions that can progress into squamous cell carcinoma. Imiquimod, which belongs to the new class of immune-response modifiers, was recently shown to be effective in the treatment of AKs. The underlying mechanisms are not fully understood. OBJECTIVES: To study the expression of individual genes in uninvolved skin and AKs before therapy and to elucidate the way in which the expression of these genes is influenced by imiquimod therapy. METHODS: We treated 13 patients with AK with imiquimod and compared gene expression before, during (five patients) and after (eight patients) therapy with that in uninvolved skin. We analysed genes coding for inflammatory cytokines or their receptors, adhesion molecules, anti-apoptotic proteins, p53 and toll-like receptors (TLRs) by reverse-transcriptase polymerase chain reaction. RESULTS: Comparing uninvolved skin and untreated AK, we found significant differences in the expression of interleukin (IL)-6, hurpin, TLR7 and TLR8. During imiquimod therapy, we detected a further upregulation of interferon-alpha, IL-6, IL-10 receptor 1 and TLR7. In contrast, two anti-apoptotic genes, hurpin and HAX-1, were downregulated. We did not detect significant differences in gene expression for p53, tumour necrosis factor-alpha and alpha- and beta-catenins. Clinically, the upregulated expression of the proinflammatory cytokines correlated with the local inflammation induced by imiquimod. CONCLUSIONS: Our results indicate that specific differences in gene expression are detectable between AK and uninvolved skin. Imiquimod influenced the expression of most genes analysed in this study. This work extends previous findings on the effects of imiquimod on gene regulation in AKs.

Aged↗
PubMed2000

Tissue-engineered skin in the treatment of vitiligo lesions.

Vitiligo is characterized by the loss of skin pigmentation due to the destruction of melanocytes. Its treatment is usually difficult. For stable cases, melanocyte transplantation is the method of choice. A newly developed treatment with recombined human/porcine skin methodology, permitting easy handling of the graft, is described in the present work. In five vitiligo patients, autologous epidermal cells were obtained from pigmented thin skin biopsies. The cells were cultured on a dried cell-free porcine dermis by the 3T3 feeder layer technique. After 10 days melanocytes were regularly dispersed in confluent keratinocyte cultures. Upside-down delivery of epidermal cells was used. The epidermal layer was directly applied onto a dermabraded vitiligo lesion, with porcine dermis covering the lesion. Pigmentation started to be visible 4-6 weeks after grafting. After using the above described methodology, the pigmentation appeared in the range of 65-80% of the grafted area. Additional UVA irradiation enhanced the treatment success up to 100%. The surgical vitiligo treatment appears to be a reasonable method of choice in stable vitiligo cases of a disease lasting for at least two years, which means for approximately 5% of all vitiligo patients.

Adult↗
PubMed1999

[Standard epicutaneous tests in ambulatory care of patients at the dermatovenereology clinic].

BACKGROUND: Allergic diseases have a rising trend worldwide. Allergic contact eczema is the most frequent occupational disease. The spectrum of allergens is influenced by a number of factors. The basic method for detection of contact allergy and detection of the allergen are epicutaneous tests. The objective of the work was to evaluate the results of these tests in patients with contact dermatitis. METHODS AND RESULTS: A total of 437 patients were tested (163 men, 274 women). For testing an extended standard set of medicamentous and non-medicamentous allergens was used. In women more often positive reactions were obtained (39.5%) than men (27.5%). The mean age of women was 40 years, that of men 47 years. Both groups responded on average to 1.6 and 1.7 allergens resp. The most frequent allergen in women was nickel (17.9%) in men chromium (12.9%). Other frequent allergens in women included chromium (11.3%), Peru balsam (3.6%), HgCl2 and cobalt. In men it was nickel, cobalt (6.1%) and HgCl2. There were also concurrent allergies. (The results are not statistically significant). In youngest age group the number of women was more than sevenfold: the most frequent allergen in this group was nickel. In the group of patients above 60 years of age women also predominated (2.5x): most frequently allergy to chromium was found (9.1%). The allergic reaction to camomile and tar was significantly higher. CONCLUSIONS: The most frequent allergen in standard epicutaneous tests in women is nickel, in men chromium. Other frequent allergens are cobalt, mercury and Perubalsam. Women have a higher ratio of positive reactions, in the group under 30 years women predominate 7x, in the whole group 2.4x.

Adult↗
PubMed1998

Omega-3 fatty acid-based lipid infusion in patients with chronic plaque psoriasis: results of a double-blind, randomized, placebo-controlled, multicenter trial.

BACKGROUND: Profound changes in the metabolism of eicosanoids with increased concentrations of free arachidonic acid (AA) and its proinflammatory metabolites have been observed in psoriatic lesions. Free eicosapentaenoic acid (EPA) may compete with liberated AA and result in an antiinflammatory effect. OBJECTIVE: Our purpose was to assess the efficacy and safety of intravenously administered fish-oil-derived lipid emulsion on chronic plaque-type psoriasis. METHODS: A double-blind, randomized, parallel group study was performed in eight European centers. Eighty-three patients hospitalized for chronic plaque-type psoriasis with a severity score of at least 15 according to the Psoriasis Area and Severity Index (PASI) participated in a 14-day trial. They were randomly allocated to receive daily infusions with either a omega-3 fatty acid-based lipid emulsion (Omegavenous; 200 ml/day with 4.2 gm of both EPA and docosahexaenoic acid (DHA); 43 patients) or a conventional omega-6-lipid emulsion (Lipovenous; EPA+DHA < 0.1 gm/100 ml; 40 patients). The groups were well matched with respect to demographic data and psoriasis-specific medical history. Efficacy of therapy was evaluated by changes in PASI, in an overall assessment of psoriasis by the investigator, and a self-assessment by the patient. In one center neutrophil 4- versus 5-series leukotriene (LT) generation and platelet 2- versus 3- thromboxane generation were investigated and plasma-free fatty acids were determined. RESULTS: The total PASI score decreased by 11.2 +/- 9.8 in the omega-3 group and by 7.5 +/- 8.8 in the omega-6 group (p = 0.048). In addition, the omega-3 group was superior to the omega-6 group with respect to change in severity of psoriasis per body area, change in overall erythema, overall scaling and overall infiltration, as well as change in overall assessment by the investigator and self-assessment by the patient. Response (defined as decrease in total PASI of at least 50% between admission and last value) was seen in 16 of 43 patients (37%) receiving the omega-3 emulsion and 9 of 40 patients (23%) receiving omega-6 fatty acid-based lipid emulsion. No serious side effects were observed. Within the first few days of omega-3 lipid administration, but not in the omega-6 supplemented patients, a manifold increase in plasma-free EPA concentration, neutrophil leukotriene B5 and platelet thromboxane B3 generation occurred. CONCLUSION: Intravenous omega-3-fatty acid administration is effective in the treatment of chronic plaque-type psoriasis. This effect may be related to changes in inflammatory eicosanoid generation.

Adult↗
PubMed1996

[Langerhans cells and cutaneous immune reactions].

The epidermis is a metabolically highly active organ where in addition to other substances important cytokines are formed which play a key role in many physiological and pathophysiological reactions. They are produced in the epidermis but influence not only keratinocytes but also other epidermal cells among which for immune reactions the Langerhans cells are most important. The complexity of immune reactions anywhere in the organism greatly hampers research of this vitally important important function. The best experimental model is, however, allergic contact eczema and irritant reactions. Experimental investigations of both provide and certainly will provide findings which will clarify in an important way immune cascades of all types and thus will have a substantial impact on knowledge of the pathogenesis and will make possible quite new approaches to treatment not only of allergic diseases but also viral diseases, and last not least, also new approaches to the treatment of malignant tumours. The authors make the reader familiar with the most recent findings, their own and published ones, from the sphere of immune dermal skin reactions in conjunction with the cells of Langerhans and cytokines.

Animals↗
PubMed1995

Substance P binding in normal neonatal foreskin.

The distribution of binding sites for NTE-biotinyl-[Arg3]-substance P (SPB) was demonstrated in neonatal foreskin using a conjugate of streptavidin with horseradish peroxidase. The observed binding is reversible, and may be abrogated by either the non-peptide substance P receptor antagonist, CP-96,345, or by unlabelled substance P. The generalized epidermal distribution and focal dermal localization of SPB binding suggest that although NK-1 receptors are abundant in human neonatal foreskin, neuromodulatory mechanisms may play a significant role in epidermal physiology.

Binding Sites↗
PubMed1994

[The frequency of viral hepatitis C in patients with porphyria cutanea tarda].

BACKGROUND: High frequency of hepatitis C virus antibodies was recently ascertained in chronic hepatic porphyria in several European countries. Some authors correlate these findings with the development of PCT, considering hepatitis C-infection further factor capable of triggering clinical and laboratory manifestation of this enzymopathy. The task of the present work was to ascertain the frequency of HCV antibodies in PCT in Czech Republic by examining an extensive group of patients, followed at the porphyria-advise center. METHODS AND RESULTS: The frequency of HCV antibodies was investigated in 92 PCT-patients with the second-generation enzymatic ELISA method. At the same time, urinary porphyrin excretion and liver function tests were examined in these subjects. Simultaneously also the results of liver biopsy performed at the first presentation of the patients were taken into account. Statistically significant increase of anti-HCV antibodies (21.7%) was found in PCT-group in comparison with the results of the group of healthy blood donors (0.16%). CONCLUSIONS: HCV-infection might possibly be a factor responsible for the development of PCT in case of proven time-dependent link between the existence of its active viraemic phase and initial symptoms of porphyria. Such an evidence has not been provided yet and remains a task for future studies.

Adult↗
PubMed1993

The lipoxygenase inhibitor 2-phenylmethyl-1-naphthol (DuP 654) is a 12(S)-hydroxyeicosatetraenoic acid receptor antagonist in the human epidermal cell line SCL-II.

The lipoxygenase inhibitor 2-phenylmethyl-1-naphthol (DuP 654) has been shown to be an active anti-inflammatory drug in a murine skin inflammation model. Since 12-HETE is assumed to have a pathophysiological role in inflammatory skin diseases, and epidermal cells possess high affinity binding sites for 12(S)-HETE, we studied the effect of DuP 654 on 12(S)-HETE binding to the human epidermal cell line SCL-II. DuP 654 antagonized 12(S)-HETE binding in a dose-dependent manner with a Ki of 3.41 +/- 0.23 nM. The antagonistic effect was reversible. After 1- and 24-hour preincubation, the drug had no more significant inhibitory effect at concentrations between 10(-10) and 10(-5) M on specific 12(S)-HETE binding (Bmax of 215,000 +/- 21,000 receptors per cell) or on receptor affinity (Kd of 3.25 +/- 0.42 nM). Our results show that DuP 654, in addition to its 5-lipoxygenase inhibitory activity, exhibits 12-HETE receptor antagonist effect, and therefore may be of benefit in skin diseases with elevated 12-HETE levels.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1993

Increase of endothelaemia in psoriasis.

Changes of blood vessel endothelium in psoriasis have not been fully documented in the literature. The aim of our study was to ascertain whether in cases of such involvement an increase of endothelaemia could be identified. The counts of circulating endothelial cells were significantly increased in psoriatics compared with healthy individuals and patients with atopic eczema. The explanation of this observation may be based on the endothelial cell replacement stimulation in psoriasis.

Adolescent↗
PubMed1993

Down-regulation of epidermal growth factor receptors by dithranol.

Dithranol is highly effective in the treatment of psoriasis, but the exact mechanism of action is not known. Since persistent expression of epidermal growth factor (EGF) receptors in psoriatic epidermis is assumed to have pathogenetic significance, we have studied the effects of dithranol on EGF binding to the human epidermal cell line SCL-II. After treatment of cells with dithranol or its therapeutically inactive oxidation product, danthrone, radioligand binding assays were performed with 125I-EGF. In therapeutically active concentrations (0.25-1 micrograms/ml) dithranol induced a decrease in EGF binding in a dose dependent manner. Danthrone was inactive. The inhibition occurred after a latency period of 6 h and reached its maximum at 24 h. At the concentration of 1 microgram/ml, the drug led to approximately a 70% decrease in the number of specific high-affinity EGF receptors (Bmax), whereas receptor affinity (Kd) showed no change. The down-regulation of EGF receptors on epidermal cells by dithranol may contribute to its antipsoriatic action.

Anthralin↗
PubMed1993

[Psoriasis arthropathica].

BACKGROUND: Five to seven percent of patients with psoriasis suffer additionally from accompanying arthritis. AIM OF THE STUDY: In this article, we review the current knowledge on clinical, diagnostic and therapeutic aspects of the disease. PATIENTS AND RESULTS: Data are presented on the treatment of six patients with the immunosuppressant ciclosporin. Therapeutic results with this drug are superior to agents traditionally used for management of psoriatic arthritis. CONCLUSION: The therapeutic options have been enlarged by the introduction of new immunosuppressive drugs, particularly ciclosporin.

Adolescent↗
PubMed1993

Characterization of high-affinity 12(S)-hydroxyeicosatetraenoic acid (12(S)-HETE) binding sites on normal human keratinocytes.

Eicosanoids are thought to play an important role in the pathogenesis of inflammatory skin diseases. The object of the present study was the detection and characterization of putative 12(S)-hydroxyeicosatetraenoic acid (12(S)-HETE) binding sites in normal human keratinocytes. Keratinocytes were obtained from foreskin and dermatome-shaved normal human skin. Radioligand binding assays were performed with 12(S)-[3H]HETE on cultured cells. Analysis of saturation curves suggested a one-site model for 12(S)-HETE binding with a KD of 3.84 +/- 0.18 nM and receptor number Bmax of 2.32 +/- 0.12 x 10(5) per cell. Ligand binding was reversible. The rank order of potency in competition for 12(S)-[3H]HETE was 12(S)-HETE > 12(R)- HETE > or = leukotriene B4. Preincubation of cells with 12(S)-HETE (2 x 10(-6) M) resulted in down-regulation of the binding site by approximately 50%. The identification and characterization of specific 12(S)-HETE binding sites on normal human keratinocytes should enable further elucidation of the role of 12-HETE in cutaneous biology and in the pathophysiology of psoriasis and other inflammatory and hyperproliferative dermatoses.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1992

Interleukin-8 receptor-mediated chemotaxis of normal human epidermal cells.

Normal human keratinocytes show chemotactic behavior towards interleukin-8 (IL-8). Under physiological conditions this cytokine seems to be present in an equilibrium between monomeric and dimeric forms, as indicated by Western blotting data. Radioligand binding studies suggest that keratinocyte chemotaxis is mediated by receptors specific for IL-8 dimers. IL-8 receptor-specific mRNA can be detected in a keratinocyte cell line by polymerase chain reaction.

3T3 Cells↗
PubMed1992

Langerhans cells of the human skin possess high-affinity 12(S)-hydroxyeicosa tetraenoic acid receptors.

The arachidonic acid metabolite 12-hydroxyeicosatetraenoic acid (12-HETE) is the main eicosanoid formed by epidermal cells and is assumed to play an important role in skin physiology and pathophysiology. Our aim was to find out whether epidermal Langerhans cells possess specific receptors for 12-HETE which would mediate the effects of this eicosanoid in their skin microenvironment. By radioligand binding studies on isolated human Langerhans cells, we could identify specific binding sites for 12(S)-HETE. The analysis of binding data revealed a single class of binding sites with a Kd of 3.32 +/- 0.45 nM and a Bmax of 691,000 +/- 58,000 receptors per cell. The binding was saturable, readily reversible, and specific for 12(S)-HETE. The receptor is likely to mediate the potent chemotactic response of human Langerhans cells towards 12(S)-HETE, which we previously described. Our results strongly suggest that extremely low concentrations of 12-HETE which is formed by epidermal keratinocytes may dramatically influence the biology of Langerhans cells by receptor-mediated effects.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1992

Defect of epidermal 12(S)-hydroxyeicosatetraenoic acid receptors in psoriasis.

12-hydroxyeicosatetraenoic acid (12-HETE) is assumed to play a central role in the pathophysiology of psoriasis. Since its effects in skin are mediated by specific high-affinity receptors, we studied the receptor characteristics in cultured epidermal cells from involved and apparently healthy skin of psoriasis patients by radioligand binding assay. Involved and uninvolved psoriatic epidermal cells showed a fourfold decrease in the number of 12-HETE binding sites as compared with normal healthy individuals and patients with atopic dermatitis, while receptor affinity remained unchanged. The decrease in receptor number was evident in psoriatic cells even in long-term culture and was not due to receptor down-regulation, defective response to interferon gamma or to protease degradation of receptor protein. The decrease in the number of 12-HETE receptors detectable even in clinically normal psoriatic skin functionally leads to diminished 12-HETE uptake and may thus represent a primary central molecular defect in the pathophysiology of the disease.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1992

Interleukin-8 receptors in normal and psoriatic polymorphonuclear leukocytes.

Polymorphonuclear leukocyte (PMNL) infiltration is an important characteristic in psoriatic lesions. The proinflammatory 8-kD peptide interleukin-8 (IL-8) is present in psoriatic scales and possesses a high chemotactic activity on human neutrophils, which may relate to its role in psoriasis. Its chemotactic activity is mediated via specific receptors on PMNL. The goal of our work was to ascertain whether PMNL infiltration in psoriasis can be accounted for by functional abnormalities of the circulating PMNL due to alterations in the IL-8 receptor density or affinity (or both). Results of radioligand binding studies performed in 10 psoriatic patients, 10 patients with atopic eczema and 11 normal controls showed no difference in receptor affinity (Kd) between the groups. However, a slight but significant elevation in IL-8 receptor density was seen on PMNL from psoriatic individuals (31,230 +/- 3,237 binding sites per cell) compared to those from normal volunteers (24,152 +/- 2,643) and atopic eczema patients (24,092 +/- 2,743). Increased number of IL-8 receptors may, besides elevated cutaneous IL-8 concentrations, contribute to the intraepidermal accumulation of PMNL in psoriasis.

Adult↗