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P.c.m. Van De Kerkhof - One of the best experts on this subject based on the ideXlab platform.
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the effects of oral liarozole on epidermal proliferation and differentiation in severe plaque psoriasis are comparable with those of acitretin
British Journal of Dermatology, 1998Co-Authors: A L A Kuijpers, P.c.m. Van De Kerkhof, J P A Van Pelt, M Bergers, P J Boegheim, J Den E N Bakker, G Siegenthaler, J SchalkwijkAbstract:The imidazole derivative liarozole is a potent inhibitor of cytochrome P450-dependent 4-hydroxylation of endogenous all-trans retinoic acid, thereby increasing the levels of all-trans retinoic acid in both plasma and skin. As part of a large, double-blind, randomized clinical study, we investigated the cell biological alterations in uninvolved and lesional skin of 20 patients with severe plaque psoriasis, who were treated with either liarozole or acitretin. The extent and severity of the skin lesions, as recorded by the Psoriasis Area and Severity Index score, was significantly reduced (P proliferation (Ki-67-positive cells), normal differentiation (transglutaminase) and abnormal differentiation [Cytokeratin 16 and skin-derived antileucoproteinase (SKALP), also known as elafin] was seen in both groups. No significant differences were noted in clinical scores or cell biological scores between the liarozole- and acitretin-treated group. None of the markers returned to the levels seen in uninvolved skin or in normal human skin. The expression of epidermal fatty acid binding protein (E-FABP) was only minimally decreased after 12 weeks of treatment, a substantial part of the stratum spinosum remaining positive. SKALP levels in serum fell in both groups with similar kinetics and showed a statistically significant correlation with clinical scores. A remarkable finding in the uninvolved skin of patients treated with liarozole or acitretin was the distinct focal expression of SKALP in the granular layer and the expression of E-FABP in the spinous layers, which is not found in normal human skin. Although the mechanism of action differs fundamentally, liarozole and acitretin show similar effects with respect to clinical effects and cell biological changes in the lesional and non-lesional skin.
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Hypertrophic scarring is associated with epidermal abnormalities: An immunohistochemical study
The Journal of pathology, 1998Co-Authors: M.p.m. Andriessen, P.c.m. Van De Kerkhof, Frank B. Niessen, Joost SchalkwijkAbstract:The role of epidermal keratinocytes in the early phases of normal unimpaired wound healing has been studied extensively. However, little is known about the cell biological processes in the epidermis and the basal membrane zone during the later phases of dermal matrix formation and remodelling of the scar tissue. This study investigated epidermal growth and differentiation and maturation of the basal membrane zone. Biopsies were taken from (clinically) hypertrophic and non-hypertrophic scars at 3 and 12 months after a breast-reduction operation. Tissues were analysed using immunohistochemical techniques. The data showed that epidermal abnormalities with respect to differentiation persist up to 3 months, as witnessed by the expression of Cytokeratin 16. Remarkably, hypertrophic scars that remained hypertrophic throughout the period of analysis (up to 12 months) showed significantly more Cytokeratin 16 expression at 3 months, when compared either with normal scars or with hypertrophic scars that became normal after 12 months. Staining for Ki-67 antigen, a marker for cell proliferation, revealed an increase in basal keratinocyte proliferation rate in 3-month-old hypertrophic scars compared with non-hypertrophic scars. After 12 months, this difference had disappeared completely and the number of cycling basal cells had returned to normal values. Three-month-old hypertrophic scars showed more acanthosis than non-hypertrophic scars of the same age, irrespective of whether they remained hypertrophic or became normal scars. After 12 months, this difference was no longer present. Staining for various heparan sulphate proteoglycan epitopes revealed that restoration of the basal membrane was incomplete at 3 months, but was complete at 12 months with respect to this component. No differences in the expression of several components of the basal membrane zone (heparan sulphate proteoglycan, laminin, tenascin) were noted between hypertrophic and non-hypertrophic scars. These data show that in the early phase of hypertrophic scarring, epidermal abnormalities are found compared with normal wound healing. In addition, early (3 months) epidermal abnormalities are associated with the clinical outcome at 12 months. These findings raise the possibility that the epidermal compartment is involved in the pathogenic process.
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skin derived antileukoproteinase skalp and epidermal fatty acid binding protein e fabp two novel markers of the psoriatic phenotype that respond differentially to topical steroid
Acta Dermato-venereologica, 1997Co-Authors: A L A Kuijpers, P.c.m. Van De Kerkhof, A M G Bergers, P Siegenthaler, Patrick L J M Zeeuwen, Joost SchalkwijkAbstract:Recently we have described two novel markers for disturbed epidermal differentiation, which are strongly upregulated in psoriatic epidermis: skin-derived antileukoproteinase (SKALP) and epidermal fatty acid-binding protein (E-FABP). No data are available on the kinetics of SKALP and E-FABP expression in vivo and the relation with epidermal growth and differentiation. We used treatment of lesional psoriatic skin with topical steroid as a model to correlate the expression pattern of SKALP and E-FABP with known cell biological events during regression of the psoriatic lesion. Expression of these markers was studied using immunohistochemistry and Northern blot analysis. After 4 weeks of treatment a substantial clinical improvement was induced by the topical steroid, whereas no significant improvement had occurred at the placebo-treated sides. The expression of SKALP following treatment with steroid was nearly undetectable both at the protein and mRNA level. Mitotic activity, as measured by Ki-67 staining, and Cytokeratin 16 expression were downregulated to normal levels in the steroid-treated epidermis. In contrast, although there was a marked decrease of E-FABP mRNA, the staining pattern for E-FABP at the protein level was not affected. After 4 weeks of treatment with steroid the complete suprabasal compartment remained positive, even after considerable clinical improvement of the lesion. We conclude that SKALP and Cytokeratin 16 are markers that are downregulated even before complete macroscopic clearance of the lesion. The kinetics of E-FABP expression is distinct from the other molecules and lags behind the clinical signs of psoriasis.
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Epidermal proliferation is not impaired in chronic venous ulcers.
Acta dermato-venereologica, 1995Co-Authors: M.p.m. Andriessen, Joost Schalkwijk, B.h. Van Bergen, K.i.j. Spruijt, P.c.m. Van De KerkhofAbstract:In this study we have investigated epidermal growth and differentiation during wound healing in human skin. The studies were performed in excisional wounds in normal skin and in chronic venous ulcers. Tissues were analyzed by immunohistochemical staining for proliferation-associated nuclear antigens (PCNA and Ki-67 antigen) and Cytokeratin 16. Healing of excisional wounds was studied from day 2 to 14. Recruitment of resting (G 0 ) epidermal cells started within 2 days after wounding ; the number of cycling cells was maximal at day 4 and continued to be increased (compared to baseline levels in normal skin) after wound closure (7-14 days). Cytokeratin 16, a proliferation-associated keratin, was induced within 48 h and was expressed in the suprabasal keratinocytes of the wound edge. Cytokeratin 16 expression was maximal at day 4 and was still present in the neo-epidermis after restoration of epidermal continuity (7-14 days). Surprisingly, in chronic venous ulcers, cycling cells were present in the wound edges of all stages of the leg ulcers studied. Both the number and localization of cycling cells were similar to those in normal wound hearing. Cytokeratin 16 was strongly expressed in all these ulcers. Our in vivo data demonstrate that recruitment of G 0 -cells into the cell cycle is not impaired in venous ulcers, which suggests that epidermal proliferation is not a limiting factor in the healing process of chronic venous ulcers.
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Cytokeratin expression in alopecia areata hair follicles.
Acta dermato-venereologica, 1994Co-Authors: H.m.j. Van Baar, P.c.m. Van De Kerkhof, I. M. J. J. Van Vlijmen, F. C. S. Ramaekers, G.n.p. Van Muijen, Sergey M. Troyanovsky, C. M. Perret, Joost SchalkwijkAbstract:Alopecia areata is a human hair disease of unknown etiology. Immunological mechanisms, alterations in the extracellular matrix and follicular growth abnormalities have been suggested as a possible cause. Here we compare the expression of Cytokeratins in normal hair follicles to that of alopecia areata using immunohistology with monoclonal antibodies. A number of Cytokeratins were specifically expressed in defined anatomical parts of the follicle; however, no gross qualitative or quantitative differences were found between normal and diseased scalp. Interestingly, the expression of Cytokeratin 16, which is modulated by conditions that affect the rate of keratinocyte proliferation, was found to be unchanged in the outer root sheet of alopecia areata follicles. This is in contrast with earlier observations of a decrease in the expression of the proliferation-associated, Ki-67 nuclear antigen.
J. David Clark - One of the best experts on this subject based on the ideXlab platform.
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Neuropeptide regulation of adaptive immunity in the tibia fracture model of complex regional pain syndrome
Journal of Neuroinflammation, 2018Co-Authors: Wen-wu Li, Frank Birklein, Tanja Schlereth, Wade S. Kingery, J. David ClarkAbstract:Background Both dysfunctional neuropeptide signaling and immune system activation are characteristic of complex regional pain syndrome (CRPS). Unknown is whether substance P (SP) or calcitonin gene-related peptide (CGRP) support autoantibody production and, consequently, nociceptive sensitization. Methods These experiments involved the use of a well-characterized tibia fracture model of CRPS. Mice deficient in SP expression (Tac1^−/−) and CGRP signaling (RAMP1^−/−) were used to probe the neuropeptide dependence of post-fracture sensitization and antibody production. The deposition of IgM in the spinal cord, sciatic nerves, and skin was followed using Western blotting, as was expression of the CRPS-related autoantigen Cytokeratin 16 (Krt16). Passive serum transfer to B-cell-deficient muMT mice was used to assess the production of functional autoantibodies in CRPS model mice. The use of immunohistochemistry allowed us to assess neuropeptide-containing fiber distribution and Langerhans cell abundance in mouse and human CRPS patient skin, while Langerhans cell-deficient mice were used to assess the functional contributions of these cells. Results Functional SP and CGRP signaling were required both for the full development of nociceptive sensitization after fracture and the deposition of IgM in skin and neural tissues. Furthermore, the passive transfer of serum from wildtype but not neuropeptide-deficient mice to fractured muMT mice caused enhanced allodynia and postural unweighting. Langerhans cells were increased in number in the skin of fracture mice and CRPS patients, and those increases in mice were reduced in neuropeptide signaling-deficient animals. Unexpectedly, Langerhans cell-deficient mice showed normal nociceptive sensitization after fracture. However, the increased expression of Krt16 after tibia fracture was not seen in neuropeptide-deficient mice. Conclusions Collectively, these data support the hypothesis that neuropeptide signaling in the fracture limb of mice is required for autoantigenic IgM production and nociceptive sensitization. The mechanism may be related to neuropeptide-supported autoantigen expression.
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Neuropeptide regulation of adaptive immunity in the tibia fracture model of complex regional pain syndrome
Journal of neuroinflammation, 2018Co-Authors: Tian-zhi Guo, Frank Birklein, Tanja Schlereth, Wade S. Kingery, Xiaoyou Shi, J. David ClarkAbstract:Both dysfunctional neuropeptide signaling and immune system activation are characteristic of complex regional pain syndrome (CRPS). Unknown is whether substance P (SP) or calcitonin gene-related peptide (CGRP) support autoantibody production and, consequently, nociceptive sensitization. These experiments involved the use of a well-characterized tibia fracture model of CRPS. Mice deficient in SP expression (Tac1−/−) and CGRP signaling (RAMP1−/−) were used to probe the neuropeptide dependence of post-fracture sensitization and antibody production. The deposition of IgM in the spinal cord, sciatic nerves, and skin was followed using Western blotting, as was expression of the CRPS-related autoantigen Cytokeratin 16 (Krt16). Passive serum transfer to B-cell-deficient muMT mice was used to assess the production of functional autoantibodies in CRPS model mice. The use of immunohistochemistry allowed us to assess neuropeptide-containing fiber distribution and Langerhans cell abundance in mouse and human CRPS patient skin, while Langerhans cell-deficient mice were used to assess the functional contributions of these cells. Functional SP and CGRP signaling were required both for the full development of nociceptive sensitization after fracture and the deposition of IgM in skin and neural tissues. Furthermore, the passive transfer of serum from wildtype but not neuropeptide-deficient mice to fractured muMT mice caused enhanced allodynia and postural unweighting. Langerhans cells were increased in number in the skin of fracture mice and CRPS patients, and those increases in mice were reduced in neuropeptide signaling-deficient animals. Unexpectedly, Langerhans cell-deficient mice showed normal nociceptive sensitization after fracture. However, the increased expression of Krt16 after tibia fracture was not seen in neuropeptide-deficient mice. Collectively, these data support the hypothesis that neuropeptide signaling in the fracture limb of mice is required for autoantigenic IgM production and nociceptive sensitization. The mechanism may be related to neuropeptide-supported autoantigen expression.
Joost Schalkwijk - One of the best experts on this subject based on the ideXlab platform.
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Effect of a lipid-rich emollient containing ceramide 3 in experimentally induced skin barrier dysfunction
Contact Dermatitis, 2002Co-Authors: Martina Kucharekova, Joost Schalkwijk, Peter C M Van De Kerkhof, P. G M Van De ValkAbstract:In the present study we compared the effect of a ceramide 3-containing emollient (Locobase(R) Repair) with a control emollient (vaselinum album/cremor lanette ana) and untreated damaged skin using clinical, bioengineering and immunohistochemical methods in two different models of experimentally induced skin barrier dysfunction. In model A (n = 13) skin barrier dysfunction was inflicted at three investigation sites by tape stripping. In model B (n = 13) the volunteers were patch tested at three investigation sites with sodium dodecyl sulphate (0.2%) for 4 h a day for 4 consecutive days. The investigation sites were treated once a day with the above-mentioned agents. Irritant reaction was assessed daily by erythema scoring and measurements of transepidermal water loss (TEWL). After 5D, punch biopsies were taken from all sites. Immunohistochemical assessment was carried out with respect to epidermal proliferation, epidermal differentiation and Langerhans cells. Tape stripping resulted in an erythematous reaction and an increase of TEWL associated with up-regulation of cycling cells, involucrin and expression of Cytokeratin 16. At day 4, ceramide 3-containing emollient significantly decreased (p < 0.03) the erythema score, TEWL and cycling cells in comparison with the untreated site. Repetitive exposure to SDS induced a variable degree of erythema, gradual increase of TEWL, an increase of cycling cells, and up-regulation of involucrin, E-FABP and SKALP. The treatment with the control emollient significantly prevented erythema, increase of TEWL and cycling cells at day 4 compared to the untreated site. In summary, the present study demonstrated that both tested emollients improve skin barrier in different conditions compared to the untreated skin. There is some indication that formulations containing skin-related lipids might be of benefit in barrier disruption following tape stripping. Different models and clinical trials are needed to establish the usefulness in specific conditions of emollients containing skin-related lipids.
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Sequence-specific inhibition of gene expression in intact human skin by epicutaneous application of chimeric antisense oligodeoxynucleotides.
Laboratory investigation; a journal of technical methods and pathology, 1999Co-Authors: M. Wingens, Rolph Pfundt, I.m.j.j. Van Vlijmen-willems, C.a.e.m. Van Hooijdonk, P.e.j. Van Erp, Joost SchalkwijkAbstract:Targeted and selective inhibition of keratinocyte gene expression in human epidermis could be an efficient and safe pharmacologic approach in many skin diseases. In this study we investigated whether topical application of antisense oligodeoxynucleotides (ODN) on intact human skin can be used to inhibit expression of a gene in the differentiated compartment of the epidermis. We applied a variety of 20-mer antisense and control ODN designed to hybridize to different regions on the mRNA of the inducible epidermal proteinase inhibitor skin-derived antileukoproteinase (SKALP)/elafin that was used as a model target gene. When nuclease-resistant fully phosphorothioate ODN were applied to explant cultures of human skin, they were found to be either ineffective at low doses or severely toxic at higher doses which could be attributed to the extremely high degree of protein binding found with this type of ODN. When chimeric ODN with a phosphodiester core and phosphorothioate 5' and 3' ends were applied to intact skin, no toxicity was noted. One of the tested chimeric ODN, that exhibit only minor protein binding, was found to inhibit SKALP expression at the protein level in a dose-dependent manner. The observed inhibition on SKALP expression levels was specific as evaluated by application of strict criteria. Sequence specificity was assessed by the addition of sense and scrambled ODN which were ineffective. Furthermore the expression levels of three other differentiation-related genes (involucrin, Cytokeratin 16, and secretory leukocyte proteinase inhibitor) were not affected, indicating that the inhibition was gene specific. Confocal laser scanning analysis of fluorescently labeled ODN confirmed that these molecules can easily penetrate the epidermis and localize in the cytoplasm of differentiated keratinocytes. We conclude that topical application of antisense ODN can be used to modulate epidermal gene expression, and could potentially be useful to inhibit expression of genes that are relevant in skin diseases.
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Hypertrophic scarring is associated with epidermal abnormalities: An immunohistochemical study
The Journal of pathology, 1998Co-Authors: M.p.m. Andriessen, P.c.m. Van De Kerkhof, Frank B. Niessen, Joost SchalkwijkAbstract:The role of epidermal keratinocytes in the early phases of normal unimpaired wound healing has been studied extensively. However, little is known about the cell biological processes in the epidermis and the basal membrane zone during the later phases of dermal matrix formation and remodelling of the scar tissue. This study investigated epidermal growth and differentiation and maturation of the basal membrane zone. Biopsies were taken from (clinically) hypertrophic and non-hypertrophic scars at 3 and 12 months after a breast-reduction operation. Tissues were analysed using immunohistochemical techniques. The data showed that epidermal abnormalities with respect to differentiation persist up to 3 months, as witnessed by the expression of Cytokeratin 16. Remarkably, hypertrophic scars that remained hypertrophic throughout the period of analysis (up to 12 months) showed significantly more Cytokeratin 16 expression at 3 months, when compared either with normal scars or with hypertrophic scars that became normal after 12 months. Staining for Ki-67 antigen, a marker for cell proliferation, revealed an increase in basal keratinocyte proliferation rate in 3-month-old hypertrophic scars compared with non-hypertrophic scars. After 12 months, this difference had disappeared completely and the number of cycling basal cells had returned to normal values. Three-month-old hypertrophic scars showed more acanthosis than non-hypertrophic scars of the same age, irrespective of whether they remained hypertrophic or became normal scars. After 12 months, this difference was no longer present. Staining for various heparan sulphate proteoglycan epitopes revealed that restoration of the basal membrane was incomplete at 3 months, but was complete at 12 months with respect to this component. No differences in the expression of several components of the basal membrane zone (heparan sulphate proteoglycan, laminin, tenascin) were noted between hypertrophic and non-hypertrophic scars. These data show that in the early phase of hypertrophic scarring, epidermal abnormalities are found compared with normal wound healing. In addition, early (3 months) epidermal abnormalities are associated with the clinical outcome at 12 months. These findings raise the possibility that the epidermal compartment is involved in the pathogenic process.
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A histological and immunohistochemical study on chronic irritant contact dermatitis
American journal of contact dermatitis : official journal of the American Contact Dermatitis Society, 1998Co-Authors: Joost Schalkwijk, Peter C M Van De Kerkhof, Urban Van Haelst, Pieter G. M. Van Der ValkAbstract:Background: Chronic irritant contact dermatitis (CICD) is characterized by erythema, scaling, hyperkeratosis, chapping and fissures. It may be the result of skin damage evoked by the cumulative effect of a variety of irritant stimuli. The diagnosis of CICD is made on basis of the patient's history and clinical features. No specific diagnostic tests are available. Objective: The histopathologic and cell biological features of CICD have not been extensively studied. Here, we describe the histological and immunohistological changes in CICD. Methods: Punch biopsies were taken from 11 patients with CICD for hematoxylin eosin and immunohistochemical stainings. Four skin biopsies of the palms of the hands of healthy volunteers served as controls. Results: The histopathologic pattern was characterized by different grades of hyperkeratosis, parakeratosis, spongiosis, exocytosis, acanthosis, and mononuclear perivascular infiltrates. Mitotic activity, as measured by Ki-67-staining in the epidermis, was increased fourfold in involved skin as compared with normal skin. Involucrin, a structural protein of the cornified envelope, was expressed from the stratum granulosum throughout the stratum spinosum in all patients with CICD and was upregulated in comparison with normal skin. Epidermal fatty-acid binding protein (E-FABP), a terminal differentiation marker, was proportionally unaltered in the CICD as compared with the normal skin and was localized from the stratum granulosum to the upper layers of the stratum spinosum. Cytokeratin 16, a differentiation marker expressed in hyperproliferative epidermis, was markedly increased from the stratum granulosum throughout the stratum spinosum in 5 out of 11 patients with CICD. Skin-derived antiproteinase (SKALP)/elafin, a proteinase inhibitor expressed in inflamed epidermis, was only detected within the stratum granulosum in 3 out of 11 patients. Conclusion: We conclude that CICD is clinically characterized by features of a chronic dermatitis and, at the histological level, by inflammatory changes, epidermal hyperproliferation and altered differentiation.
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skin derived antileukoproteinase skalp and epidermal fatty acid binding protein e fabp two novel markers of the psoriatic phenotype that respond differentially to topical steroid
Acta Dermato-venereologica, 1997Co-Authors: A L A Kuijpers, P.c.m. Van De Kerkhof, A M G Bergers, P Siegenthaler, Patrick L J M Zeeuwen, Joost SchalkwijkAbstract:Recently we have described two novel markers for disturbed epidermal differentiation, which are strongly upregulated in psoriatic epidermis: skin-derived antileukoproteinase (SKALP) and epidermal fatty acid-binding protein (E-FABP). No data are available on the kinetics of SKALP and E-FABP expression in vivo and the relation with epidermal growth and differentiation. We used treatment of lesional psoriatic skin with topical steroid as a model to correlate the expression pattern of SKALP and E-FABP with known cell biological events during regression of the psoriatic lesion. Expression of these markers was studied using immunohistochemistry and Northern blot analysis. After 4 weeks of treatment a substantial clinical improvement was induced by the topical steroid, whereas no significant improvement had occurred at the placebo-treated sides. The expression of SKALP following treatment with steroid was nearly undetectable both at the protein and mRNA level. Mitotic activity, as measured by Ki-67 staining, and Cytokeratin 16 expression were downregulated to normal levels in the steroid-treated epidermis. In contrast, although there was a marked decrease of E-FABP mRNA, the staining pattern for E-FABP at the protein level was not affected. After 4 weeks of treatment with steroid the complete suprabasal compartment remained positive, even after considerable clinical improvement of the lesion. We conclude that SKALP and Cytokeratin 16 are markers that are downregulated even before complete macroscopic clearance of the lesion. The kinetics of E-FABP expression is distinct from the other molecules and lags behind the clinical signs of psoriasis.
Jessica Fransson - One of the best experts on this subject based on the ideXlab platform.
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Tumour necrosis factor-alpha does not influence proliferation and differentiation of healthy and psoriatic keratinocytes in a skin-equivalent model.
Acta dermato-venereologica, 2000Co-Authors: Jessica FranssonAbstract:Tumour necrosis factor-alpha (TNF-alpha) has been implicated in the pathogenesis of psoriasis. Its effect on keratinocytes from healthy and psoriatic skin was investigated. The keratinocytes were co-cultured with healthy and psoriatic fibroblasts in skin equivalents and grown in a serum-free medium for 15 days. TNF-alpha was added, or not, on day 12. The expression of differentiation and proliferation markers was investigated with immunohistochemistry. The epidermal growth rate was assessed by the percentage of Ki-67-positive nuclei in the basal layers of the outgrowths, which were all multilayered and orthokeratotic. The expression of the epidermal growth factor receptor, Cytokeratin 16, involucrin and filaggrin displayed a hyperproliferative, regenerative pattern. No statistically significant differences in growth rate were found between the groups. These findings indicate a lack of effect of TNF-alpha on proliferation and differentiation in healthy and psoriatic keratinocytes. Further studies are warranted to elucidate the pathophysiological role of TNF-alpha in psoriasis.
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The effect of IFN-γ on healthy and psoriatic keratinocytes in a skin equivalent model is influenced by the source of the keratinocytes and by their interactions with fibroblasts
Archives of Dermatological Research, 1996Co-Authors: Jessica Fransson, Annika Scheynius, Qian Shen, Hans HammarAbstract:We investigated the effect of interferon-gamma (IFN-γ) on skin equivalents. Keratinocytes from involved and uninvolved skin from psoriatic subjects and from healthy subjects were grown on preproduced dermal equivalents (DE) containing fibroblasts from healthy skin or psoriatic lesions. Healthy keratinocytes were added when the dermal equivalents were either 22 days (DE(22)) or 37 days old (DE(37)) and psoriatic keratinocytes when the dermal equivalents were 28–52 days old (DE(28–52)). The skin equivalents were cultured for 11 days in a serum-free medium, and then with or without 500 U/ml IFN-γ for 6 days. The expression of markers associated with differentiation and proliferation were investigated by immunohistochemistry. Differentiation was assessed by computed scores for the expression of Cytokeratin 16, involucrin, filaggrin and the receptor for epidermal growth factor. The differentiating effect of IFN-γ on healthy keratinocytes grown on DE(37) was significantly stronger than on psoriatic keratinocytes grown on DE(28–52). In healthy keratinocytes, the differentiating effect of IFN-γ was significantly stronger in skin equivalents containing DE(37) than in those containing DE(22). The proliferation rate, i.e. the percentage of Ki-67 ^ + keratinocytes in the basal layer, was studied in healthy keratinocytes grown on DE(22). In these cultures IFN-γ increased the proliferation rate in the presence of psoriatic fibroblasts but not in the presence of healthy fibroblasts. HLA-DR expression was induced only in healthy keratinocytes grown on DE(22). We conclude that the influence of IFN-γ on epidermal differentiation and proliferation is influenced by the origins of both the keratinocytes and the fibroblasts. These findings suggest that interactions between keratinocytes and fibroblasts might be involved in the pathogenesis of psoriasis.
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Proliferation and interferon-γ receptor expression in psoriatic and healthy keratinocytes are influenced by interactions between keratinocytes and fibroblasts in a skin equivalent model
Archives of Dermatological Research, 1995Co-Authors: Jessica Fransson, Hans Hammar, Axel Emilson, Annika ScheyniusAbstract:Epidermal-dermal interactions were studied in a skin equivalent model. Six combinations of keratinocytes and fibroblasts from healthy and psoriatic skin were used. TPA (12- O -tetradecanoylphorbol-13-acetate) was used to determine whether the expression of the IFN-γ receptors in keratinocytes was related to epidermal differentiation and proliferation. These phenomena were assessed by immunohistochemistry. In all epidermal outgrowths, the epidermal growth factor receptor was expressed throughout the epidermis, Cytokeratin 16 suprabasally, and filaggrin and involucrin in its superficial part. The IFN-γ receptor was expressed throughout the epidermis, but was unevenly distributed. The expression of the IFN-γ receptor was quantified by confocal laser scanning microscopy both in the whole of epidermis and in areas with the strongest intensity. The total amount varied to a minor degree in the epidermal outgrowths of different origins and was unaffected by TPA. In high-intensity areas interactions between keratinocytes and fibroblasts did influence the amount of IFN-γ receptor expression and TPA decreased the expression by 13%. There was no correlation between the proliferation rate and the expression of the IFN-γ receptor. Psoriatic and healthy keratinocytes were equally well differentiated in the skin equivalents. The interferon-γ receptor was similarly expressed under these conditions. The growth rate, assessed by Ki-67-positive nuclei in the basal layer, was highest in healthy keratinocytes. Keratinocytes from psoriatic lesions increased their growth rate when cocultured with psoriatic fibroblasts compared with normal ones, indicating that fibroblasts may be of importance for epidermal hyperproliferation in psoriatic lesions.
J Schalkwijk - One of the best experts on this subject based on the ideXlab platform.
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The effect of the PDE-4 inhibitor (cipamfylline) in two human models of irritant contact dermatitis
Archives of Dermatological Research, 2003Co-Authors: Martina Kucharekova, J Schalkwijk, M. Hornix, T. Ashikaga, S. T'kint, G. J. Jongh, P. C. M. Kerkhof, P. G. M. ValkAbstract:Background New therapeutic approaches have to be considered in the treatment of irritant contact dermatitis (ICD). Recently, phosphodiesterase 4 (PDE-4) inhibitors have been introduced as nonsteroidal, antiinflammatory agents. These agents inhibit the secretion of the cytokines thought to be involved in the pathogenesis of ICD. We investigated the effect of a new selective PDE-4 inhibitor (cipamfylline) in human models using single and repeated exposures to an irritant in a blind, randomized pilot study with healthy volunteers. We compared the effect of cipamfylline ointment with a strong corticosteroid (betamethasone-17-valerate) and with a placebo ointment. Methods Ten volunteers were patch tested at four investigation sites with sodium dodecyl sulphate (1%) for 24 h. In a model that simulates chronic damage, 11 volunteers were patch tested with sodium dodecyl sulphate (0.2%) for 4 h daily for four consecutive days. The investigation sites were treated once a day with the above-mentioned agents. One site was left untreated. We used erythema scoring, measurements of transepidermal water loss (TEWL) and several immunohistochemical markers for epidermal proliferation and differentiation. Results Repeated application revealed that betamethasone-17-valerate caused a statistically significant reduction in erythema and TEWL compared to cipamfylline and placebo. We also observed a significant suppression of proliferating cells and Cytokeratin 16 expression at sites treated with betamethasone compared to the other sites. In the model for acute ICD, no significant differences were seen between the investigated sites. Conclusions Our results show that betamethasone-17-valerate may modulate the response in ICD. In this human model of ICD we could not confirm the efficacy of cipamfylline. Clinical studies are needed before the effect of PDE-4 inhibitors in ICD can be refuted with certainty.
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Oral keratinocytes cultured on dermal matrices form a mucosa-like tissue.
Biomaterials, 2002Co-Authors: R Ophof, R.e.m Van Rheden, J.w. Von Den Hoff, J Schalkwijk, Anne Marie Kuijpers-jagtmanAbstract:Abstract Oral reconstructions for cleft palate repair are often complicated by a shortage of mucosal tissue. This shortage causes scar tissue formation leading to impaired growth of the dento-maxillary complex. The overall aim of our research is to develop a substitute, which limits the iatrogenic effects of cleft palate surgery. This study describes the culture and characterization of mucosal substitutes containing keratinocytes. Epidermal and oral keratinocytes from a beagle dog were cultured on several skin-derived and collagen-based substrates. Oral keratinocytes cultured on the skin-derived substrates closely resembled normal oral epithelium of the dog. A multi-layered epithelium was formed showing parakeratosis, expression of Cytokeratin 16 and the formation of a basement membrane. Epidermal keratinocytes cultured on the skin-derived substrates formed an epithelium which was similar to dog epidermis. In contrast, keratinocytes cultured on the collagen-based substrates invaded the substrate without the formation of a multi-layered epithelium. In conclusion, this study shows that oral canine keratinocytes cultured on skin-derived substrates exhibit a tissue organization that resembles normal oral mucosa. This type of mucosal substitute will therefore be used in further studies for implantation on the palate of beagle dogs. These studies might eventually lead to an improvement of cleft palate surgery in humans.
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the effects of oral liarozole on epidermal proliferation and differentiation in severe plaque psoriasis are comparable with those of acitretin
British Journal of Dermatology, 1998Co-Authors: A L A Kuijpers, P.c.m. Van De Kerkhof, J P A Van Pelt, M Bergers, P J Boegheim, J Den E N Bakker, G Siegenthaler, J SchalkwijkAbstract:The imidazole derivative liarozole is a potent inhibitor of cytochrome P450-dependent 4-hydroxylation of endogenous all-trans retinoic acid, thereby increasing the levels of all-trans retinoic acid in both plasma and skin. As part of a large, double-blind, randomized clinical study, we investigated the cell biological alterations in uninvolved and lesional skin of 20 patients with severe plaque psoriasis, who were treated with either liarozole or acitretin. The extent and severity of the skin lesions, as recorded by the Psoriasis Area and Severity Index score, was significantly reduced (P proliferation (Ki-67-positive cells), normal differentiation (transglutaminase) and abnormal differentiation [Cytokeratin 16 and skin-derived antileucoproteinase (SKALP), also known as elafin] was seen in both groups. No significant differences were noted in clinical scores or cell biological scores between the liarozole- and acitretin-treated group. None of the markers returned to the levels seen in uninvolved skin or in normal human skin. The expression of epidermal fatty acid binding protein (E-FABP) was only minimally decreased after 12 weeks of treatment, a substantial part of the stratum spinosum remaining positive. SKALP levels in serum fell in both groups with similar kinetics and showed a statistically significant correlation with clinical scores. A remarkable finding in the uninvolved skin of patients treated with liarozole or acitretin was the distinct focal expression of SKALP in the granular layer and the expression of E-FABP in the spinous layers, which is not found in normal human skin. Although the mechanism of action differs fundamentally, liarozole and acitretin show similar effects with respect to clinical effects and cell biological changes in the lesional and non-lesional skin.
