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Histopathology of the Nasal Cavity in Laboratory Animals Exposed to Cigarette Smoke and Other Irritants
Published in D. V. M. Gerd Reznik, Sherman F. Stinson, Nasal Tumors in Animals and Man, 2017
The lamina propria of the nasal cavity is highly vascular especially around the turbinate bones. It is infiltrated lightly and diffusely by mononuclear inflammatory cells and there are focal accumulations of lymphocytes, frequently near the nasolacrimal ducts. Globule leucocytes have been described among the epithelial cells of both respiratory and olfactory regions, particularly in females.35 Serous glands and their ducts are numerous in the propria of the septum and lateral walls and Bowman’s glands occur in the olfactory mucosa. In the septum, between the olfactory mucosa and the vomeronasal organ, the more dorsal glands are PAS-negative and the more ventral are PAS-positive.35 (See also Chapters 1 and 2, Volume I.)
Nasal Neuroblastomas in Man
Published in Gerd Reznik, Sherman F. Stinson, Nasal Tumors in Animals and Man, 2017
Elvio G. Silva, Bruce Mackay, James J. Butler
Despite the absence of olfactory differentiation in six of our nine neuroblastomas, the similarity of the small cell component in all nine cases argues for a common histogenesis and the basal cell of the olfactory epithelium is the logical candidate. It is more difficult to advance a plausible theory for the origin of the neuroendocrine carcinomas. Their cells have neuroendocrine features, including cytoplasmic extensions and dense core granules, but differ from those of the neuroblastomas in having more cytoplasm and organelles, and in their arrangement in densely-packed clusters bordered in some instances by a basal lamina. They are also distinctive in their relationship to the glands which were only seen in the primary tumors and were absent in metastases. Cytologically, the glands did not appear to be neoplastic, and they were suspected to be the acini and ducts of the submucosal glands of the region (Bowman’s glands);14 the considerable variation in size and shape that they displayed could be distortion induced by pressure from the surrounding tumor. The proximity of groups of tumor cells to the glandular epithelium could be incidental contiguity and need not imply a histogenetic relationship. It is, however, probable that neuroendocrine cells located within the epithelium of the glands could be the source of the tumor. Neuroendocrine carcinomas with some similar light and ultrastructural features have been reported in various anatomic locations where they are in some instances associated with specific cell types, as in the skin where they are ascribed to the Merkel cell.16
The Ultrastructure of Olfactory and Nasal Respiratory Epithelium Surfaces
Published in D. V. M. Gerd Reznik, Sherman F. Stinson, Nasal Tumors in Animals and Man, 2017
Olfactory and respiratory mucus layers of mammals are about 5 to 11 fim thick. In the frog, the olfactory mucus layer is about 30 μm thick and the respiratory one about 13 (xm.69,88 During the preparation for scanning electron microscopy, mucus may clot onto the epithelial surface (Figure 9). The mucus of the olfactory epithelium depicts several kinds of inclusions, e.g., granular ones (Figure II).36 The mucus has a fibrous appearance in plastic embedded sections (Figure 16), but is rather continuous when using cryo-ultramicrotomy (Figures 10, 11, and 17).36 Replicas based on deep-etched, fast frozen, unfixed material show that the mucus is tremendously heterogeneous. Mucus fibers clearly attach onto cilia and microvilli, sometimes in rather specific patterns.255 The mucus often contains numerous vesicles, which are free of particles and not attached to cilia or microvilli (Figures 19, 28A, and 35A).69 Olfactory8,15,69,88,115 and respiratory mucous surfaces196 are often covered by a layer of condensed material, the so-called terminal film (Figures 4A and 5A).115 This film is also present on the mucus layer covering the sensory vomeronasal epithelium.46,81 Mucus producing glands show a heterogeneous distribution over the respiratory and olfactory epithelium. 10,197 Within one class, e.g., that of reptiles91 nasal glands may vary greatly in anatomical and histochemical properties. The ultrastructure of the Bowman glands, which are responsible for the mucus production in the olfactory epithelium, especially in mammals, has extensively been described by Seifert111 and Breipohl.198 Meneo69 shows freeze-fracture images of ducts of these glands. Histochemical studies indicated that the mucus of olfactory surfaces differs from that of the respiratory surfaces, in that the olfactory mucus demonstrates the presence of sulfomucins.107 Glands of the respiratory epithelium display also a great heterogeneity among each other with respect to their secretory products.10
Does cigarette smoke exposure lead to histopathological alterations in the olfactory epithelium? An electron microscopic study on a rat model
Published in Ultrastructural Pathology, 2018
Elvan Sahin, Gursel Ortug, Alpen Ortug
In the control group, olfactory cells (bipolar neurons) were characterized by a spindle-shaped form, apical olfactory vesicles, and an electron-lucent cytoplasm. The olfactory vesicles had many sensory cilia. Basal bodies of the cilia were observed within the lateral margins of the vesicle. On the epithelial surface, there were numerous transverse, longitudinal, and tangential profiles of cilia. The thick proximal portion of cilia had a typical “9 + 2” microtubule arrangement. Ciliary narrow regions, containing a few microtubules at the tip, were also observed. Some vesicles, which may have represented a smooth endoplasmic reticulum (SER) or exocytic or endocytic vesicles, were present in the apical portion of olfactory cells. These cells were linked by junctional complexes with adjacent supporting cells. Supporting cells had numerous long, branched microvilli extending from their apical surface. The microvilli were entangled with olfactory cilia and microvilli of neighboring cells on the epithelial surface. The cytoplasm of supporting cells was denser than that of adjacent olfactory neurons. Well-developed terminal webs were observed in the apical portion of supporting cells, separating the organelle-poor apical cytoplasm from a deeper region, where a number of mitochondria were present (Figure 2). Basal cells, small and polygonal or irregular in profile, were located on the basal lamina. Their cytoplasm, surrounding a usually indented heterochromatic nucleus, had prominent tonofilaments. Numerous cytoplasmic processes, extending from these cells, appeared to interdigitate with those of neighboring cells and to envelop the axonal termini of olfactory neurons (Figure 3). In the basal portion of the olfactory epithelium, there were ducts entering the epithelium to deliver the secretion of Bowman’s glands, situated in the lamina propria, to the olfactory surface. Duct cells, squamous in shape, had microvilli and cilia on their luminal surface, as well as cytoplasmic granules (Figure 4).
Impact of intranasal application of nerve growth factor on the olfactory epithelium in rats with chemically induced diabetes
Published in Ultrastructural Pathology, 2018
Sidika Yalim, Kenan Dağlıoğlu, Gülfidan Coskun, Sait Polat
The OE showed regenerated structure except for focal cellular changes in this group. However, the presence of slight subepithelial edema and hyperchromatic nuclei was observed. Bowman’s glands and olfactory nerve fibers in the lamina propria were seen ordinary in structure (Figure 4).
Nasal odorant metabolism: enzymes, activity and function in olfaction
Published in Drug Metabolism Reviews, 2019
Jean-Marie Heydel, Philippe Faure, Fabrice Neiers
The first evidence of glutathione transferase (GST) expression in human OEs was provided by the purification of an enzyme active against a ubiquitous GST substrate (1-chloro-2,4-dinitrobenzène) and recognized by antibodies raised against GSTs (Aceto et al. 1989). According to the nomenclature proposed for GSTs (Mannervik et al. 2005), different classes were identified in the OE and mucus (Table 2). Two different studies confirmed the identification of GSTA1 and GSTP1 in human nasal mucus (Debat et al. 2007; Yoshikawa et al. 2018). Additionally, the Mu class of GSTs were identified in the rodent OE or mucus but were not identified in humans using proteomic analysis. The enzymes found in the mucus are produced in the Bowman’s glands of the OE, but these enzymes were also observed to be expressed in the sustentacular and basal cells (Banger et al. 1994). The results of quantitative RT-PCR of human OE supported the abundance of GSTP1 mRNA and the absence of Mu class GST mRNAs (Zhang et al. 2005). Using quantitative RT-PCR, GSTP1 mRNA was not identified in rodents, and neither by mass spectrometry in the olfactory mucus or OE. All these results suggest that different GST classes are expressed in the olfactory mucus of different mammal species. Additionally, the GST protein level appears to be aging-regulated in human olfactory mucus; GSTA1, GSTA3, and GSTP1 levels in the mucus were shown to be decreased in elderly people compared with young people, and the decreased expression of these proteins correlated with the decrease in olfactory sensitivity in this population (Yoshikawa et al. 2018). In the human OE, P-class GSTs were shown to decrease after birth with immunohistochemistry. In addition, in contrast to P-class GSTs, A-class GSTs declined with age (Krishna et al. 1995). In rodents, GSTs were shown to be differentially expressed during rat development using immunohistochemical localization (Krishna et al. 1994). We can hypothesize, in this context, that these age-related variations may also contribute to the decrease in the smelling abilities of rodents and humans. Localization in the human and rat OE using class-specific antibodies (validated by Western blot analysis) should be performed in future studies to complete the observations of these pioneer studies.