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Diagnosing Skin Disease
Published in Ayşe Serap Karadağ, Lawrence Charles Parish, Jordan V. Wang, Roxburgh's Common Skin Diseases, 2022
A variety of causes are associated with blistering dermatosis, including autoimmune, infectious, and inflammatory etiologies. Autoantibodies against desmogleins 1 and 3, which are components of desmosomes that keep keratinocytes attached to one another, resulting in acantholysis, or a loss in intercellular connections, and can lead to intraepidermal blisters. In contrast, autoantibodies against components of hemidesmosomes of the dermo-epidermal junction in bullous pemphigoid result in subepidermal blisters (Figure 2.6). Herpesvirus infection of the epidermis may result in acantholysis and varying degrees of epidermal necrosis, which can lead to intraepidermal or subepidermal blisters. Significant intercellular edema in allergic contact or nummular dermatitis results in intraepidermal blisters. Any process that weakens the dermo-epidermal junction may result in a subepidermal blister (Figure 2.7). Severe dermal edema from a variety of sources may also result in a subepidermal blister (e.g., lymphedema blister, bullous insect bite, and bullous Sweet syndrome). Depending on the severity and acuity, most interface dermatitides, which are associated with a variable degree of necrosis of keratinocytes at the dermo-epidermal junction, have a subepidermal bullous expression. Examples include bullous erythema multiforme, bullous lichen planus, and bullous fixed-drug eruption.
Dermatologic diseases and pregnancy
Published in Hung N. Winn, Frank A. Chervenak, Roberto Romero, Clinical Maternal-Fetal Medicine Online, 2021
Holly Edmonds, Dana Ward, Ann G. Martin, Susana Leal-Khouri
The pemphigoid gestationis antigen has been characterized as a 180-kDa glycoprotein found in the lamina lucida of the basement membrane of skin and placenta (42,43). It is an interesting observation that pemphigoid gestationis antigen may first appear in the placenta during the second trimester of pregnancy, coinciding with the time course of the development of pemphigoid gestationis (44). This 180-kDa antigen is also known as bullous pemphigoid antigen 2 and most recently as type XVII collagen. This is a transcellular glycoprotein in the hemidesmosome with both a cytoplasmic and extracellular domain. The function of the hemidesmosome is to anchor the basal cells of the epidermis to the basement membrane thus keeping it attached to the dermis. The NC16A segment of the 180-kDa antigen is the immunoreactive site in the majority of affected patients (38).
Comparative Anatomy, Physiology, and Biochemistry of Mammalian Skin
Published in David W. Hobson, Dermal and Ocular Toxicology, 2020
The basal cell membrane of the epidermal-dermal junction is not always smooth. It may be irregular, forming finger-like projections into the dermis. The cell membrane consists of three layers, a thick internal leaflet, an electron lucent layer, and a thin external leaflet. Hemidesmosomes are sometimes found along the internal leaflet of the cell membrane. Occasionally, small vesicles (pinocytotic) are seen near and on the plasma membrane. The lamina lucida portion of the basement membrane is electron-lucent except in the hemidesmosome area, where one can see a sub-basal dense plaque and some fine filaments. The next layer is the basal lamina which is electron dense and may contain fibrillar components in an amorphous substance. The basal lamina is thicker and denser in regions beneath hemidesmosomes.
Histological study of the effect of granulocyte colony-stimulating factor on experimentally induced corneal burn in adult male albino rats
Published in Ultrastructural Pathology, 2020
Shereen Shawky Elabd, Suzan E. Abo-Elnasr, Gehan M. Soliman, Naglaa I. Sarhaan, Sadika M. Tawfik
Examination of ultrathin sections obtained from corneal specimens of control rats showed a normal histological structure of the cornea. The epithelium appeared to be formed of basal columnar cells, intermediate layers of polygonal cells, and superficial layers of squamous cells. Hemidesmosomes were observed between the basal surfaces of the basal cells and the basement membrane and beneath the corneal epithelium was Bowman’s Layer. It was a noncellular layer consisting of collagen fibers arranged in an apparently random manner (Figure 6a). The avascular corneal stroma appeared below Bowman’s Layer. It was formed of well-organized collagen fibrils in the form of lamellae oriented at right angles to each other. The attenuated keratocytes appeared spindle shaped with oval nuclei and long process (Figure 6b). Descemet’s membrane was seen as a homogenous noncellular layer interposed between the stroma and the underlying endothelium. The endothelium was seen as a continuous single layer of flat endothelial cells with flat oval euchromatic nuclei representing the posterior surface of the cornea (Figure 6c).
Cell culture models of oral mucosal barriers: A review with a focus on applications, culture conditions and barrier properties
Published in Tissue Barriers, 2018
Lisa Bierbaumer, Uwe Yacine Schwarze, Reinhard Gruber, Winfried Neuhaus
A list of immortalized cell lines that have been established from different compartments of the oral mucosa and their primary applications are given in Table 2. Analysis of monocultures revealed that immortalized keratinocytes can show functional characteristics of the epithelial barrier. Gröger et al. established immortalized human gingival keratinocyte cell lines with cytokeratin expression patterns comparable to that of primary gingival keratinocytes. Cells formed multi-layered structures, were able to develop TEER and showed expression of claudin-1, claudin-2 and occludin.254–256 One of those cell lines, namely Gie-No3B11, was used to study the influence of retinoic acid (RA) on human gingival epithelial barriers, showing increased TEER, increased claudin-4 and occludin expression, while ZO-1 was downregulated by RA treatment.256 The effect of RA on cell junctions of the gingival epithelium was also studied using the immortalized gingival cell line GE1, which was established from transgenic mice harboring a temperature-sensitive SV40T gene.257 GE1 cells form multilayered structures that are connected by desmosomes.257 Studies by Hatakeyama et al. revealed that RA treatment a) altered TJ expression of claudin-1, claudin-4, occludin and ZO-1258; b) decreased the expression of connexin gap junction Cx31.1259 and c) induced downregulation of desmosomes and loss of hemidesmosomes.260
AMPK in regulation of apical junctions and barrier function of intestinal epithelium
Published in Tissue Barriers, 2018
Mei-Jun Zhu, Xiaofei Sun, Min Du
Epithelial cells are joined by a series of intercellular junctions and polarized into the apical and the basolateral domains.30,31 The apical domain of epithelial cells is linked with adjacent epithelial cells through TJs and AJs, which are also referred to as apical junctions (Fig. 1). The assembly of apical junctions is indispensable for the formation and maintenance of epithelial barrier integrity.1,32 Desmosomes are intercellular junctions located below AJs on the lateral membrane and link to intermediate filaments to stabilize the epithelial layer and provide mechanical strength to tissues.33,34 On the basolateral membrane, hemidesmosomes connect to intermediate filament and facilitate epithelial cell adhesion to extracellular matrix in the basal lamina.35 In addition, epithelial cells communicate with surrounding cells through gap junctions (Fig. 1) that are composed of connexins and assembled into hexameric pore-forming channels.36