Browsing by Subject "Epidermis"

Now showing 1 - 4 of 4
  • Thumbnail Image
    Publication
    Open Access
    Expression of acyl-CoA synthetase 5 in human epidermis
    (Murcia : F. Hernández, 2008) Gaisa, N.T.; Köster, J.; Reinartz, A.; Ertmer, K.; Ehling, J.; Raupach, K.; Perez-Bouza, A.; Knüchel, R.; Gassler, N.
    The human epidermis is characterized by a constant renewal of keratinocytes embedded in a matrix enriched with lipids. Numerous proteins involved in lipid metabolism are found in human epidermis, especially in keratinocytes. Long-chain acyl-CoA derivatives, which are catalyzed by human ACSL5, are important metabolites in several biochemical pathways, including ceramide de novo synthesis. The aim of the present study was to investigate expression of acyl-CoA synthetase isoform 5 (ACSL5) in human epidermis by an in situ, as well as a molecular approach. We show that ACSL5 mRNA and protein are found in human epidermis, as well as in non-differentiated and differentiated HaCaT cells. Keratinocytes of stratum spinosum are the main source for ACSL5 expression in both meshed facial or abdominal skin and ridged skin of upper or lower extremities including TUNEL-positive cells in upper cellular layers. Single keratinocytes of chronic solar-exposed meshed facial epidermis occasionally display a stronger ACSL5 immunostaining. In conclusion, our study indicates that epidermal ACSL5 expression might be involved in differentiation and the stress response of keratinocytes.
  • Thumbnail Image
    Publication
    Open Access
    Immunohistochemical study of the apoptosis process in epidermal epithelial cells of rats under a physiological condition
    (F. Hernández y Juan F. Madrid. Murcia: Universidad de Murcia, Departamento de Biología Celular e Histología, 2011) Udayanga, K.G.S; Miyata, H.; Yokoo, Y.; Qi, W.M.; Takahara, E.; Mantani, Y.; Yokoyama, T.; Hoshi, N.; Kitagawa, Hiroshi
    Epidermal homeostasis is maintained by both epithelial proliferation in the stratum basale (SB) and the apoptosis of epithelial cells under physiological conditions. In this study, the induction and regulation mechanisms of epidermal apoptosis were immunohistochemically investigated in the epidermis from Wistar rat’s palm and foot pad by using several apoptotic related proteins under a physiological condition. The results showed that Fas and Fas-L were expressed in cellular membranes of the stratum spinosum (SS), whereas TNF-R1 did not show any membranous expression in any epidermal layers. TNF-α was not observed in the epidermis. Caspase-10, cleaved caspase-3 and DNase-1 were found in the epithelial cytoplasms from the SS to stratum granulosum (SG), whereas caspase-8 was not detected in the epidermis. XIAP and Bak were found in the cytoplasm from the SS to SG, and the intensity of Bak-positivity was stronger in the SG than the SS, whereas Bid, Apaf-1 and cleaved caspase-9 were restricted in the SG. Homogenous cytoplasmic immunoreactivity of Bcl-2 was found in the SB and the intensity was gradually decreased from the SB to the SG. The granular-cytoplasmic immunopositivity of cytochrome C gradually altered into homogenous cytoplasmic expression in the upper half of the SG. Single-stranded DNA was rarely detected in the upper portion of the SG. These results suggest that epidermal apoptosis is induced by the interaction between Fas and Fas-L and the activation of caspase-10, and might initially proceed through a mitochondrialindependent pathway, and that a mitochondrialdependent pathway finally accelerated under physiological conditions.
  • Thumbnail Image
    Publication
    Open Access
    Localization of sex steroid receptors in human skin
    (Murcia : F. Hernández, 2004) Pelletier, G.; Ren, L.
    Sex steroid hormones are involved in regulation of skin development and functions as well as in some skin pathological events. To determine the sites of action of estrogens, androgens and progestins, studies have been performed during the recent years to accurately localize receptors for each steroid hormone in human skin. Androgen receptors (AR) have been localized in most keratinocytes in epidermis. In the dermis, AR was detected in about 10% of fibroblasts. In sebaceous glands, AR was observed in both basal cells and sebocytes. In hair follicles, AR expression was restricted to dermal papillar cells. In eccrine sweat glands, only few secretory cells were observed to express AR. Estrogen receptor (ER) a was poorly expressing, being restricted to sebocytes. In contrast, ERß was found to be highly expressed in the epidermis, sebaceous glands (basal cells and sebocytes) and eccrine sweat glands. In the hair follicle, ERß is widely expressed with strong nuclear staining in dermal papilla cells, inner sheath cells, matrix cells and outer sheath cells including the buldge region. Progesterone receptors (PR) staining was found in nuclei of some keratinocytes and in nuclei of basal cells and sebocytes in sebaceous glands. PR nuclear staining was also observed in dermal papilla cells of hair follicles and in eccrine sweat glands. This information on the differential localization of sex steroid receptors in human skin should be of great help for future investigation on the specific role of each steroid on skin and its appendages.
  • Thumbnail Image
    Publication
    Open Access
    Melanocyte localization and distribution in human cholesteatoma
    (Murcia : F. Hernández, 2008) Olszewska, E.; Wagner, M.; Goon, Peter; Shamaa, Ali; Upile, Tao; Rogowski, Marek; Steinstaesser, Lars; Sudhoff, H.
    Introduction: Melanocytes in skin are derived from the neural crest and colonize the epidermis in the first trimester of gestation. Melanocytes have been observed in the nasopharyngeal, inner ear and oral mucosa and should therefore be present in the middle ear mucosa. Aims: To identify and determine the distribution of melanocytes in human cholesteatoma and normal meatal skin in Caucasian adults. Material and methods: Human cholesteatoma (n=18) and normal meatal skin samples (n=10) were investigated immunohistochemically with anti-HMB-45 and MART- 1 antibodies. Localization and distribution of melanocytes were assessed in the epidermis and cholesteatoma using an automatic analyzing system. Results: Regular skin exhibited melanocytes within the epidermis and accounted for 10% of the total cell number. They occurred partly as membrane-bound clusters. Cholesteatoma matrix melanocytes were observed in the basal layer and exhibited an oval or roundmorphology. Decreased numbers of melanocytes in the basal layer correlated with keratinization within cholesteatoma samples. Melanocytes revealed monomorphous nuclei, abundant cytoplasm containing particles of melanin. Found adjacent to glands and blood vessels, melanocytes were also scattered among the mesenchymal cells. Accounting for 2-6% of the total cell number within the squamous epithelium, melanocyte density was significantly lower in cholesteatoma tissue than in skin. Conclusions: The melanocyte distribution pattern was different when comparing the epithelia of skin and cholesteatoma. The presence of melanocytes in cholesteatoma may be due to an ingrowth, consequently controlled by keratinocyte-derived signals. In terms of the pathogenesis of cholesteatoma, neither squamous metaplasia nor melanocyte metaplasia can be excluded by our data.