Intermediate Filament Expression in Human Fetal Olfactory Epithelium

Abstract

\s=b\Antibodies to intermediate filaments and to desmoplakin were used to investigate the histogenetic origin of the olfactory neuroepithelium. Intermediate-filaments are tissue-specific molecular cytoskeletal markers; desmoplakin is the major desmosomal protein. The olfactory epithelia of eight human fetuses, aged 7 to 10 weeks (fertilization age) were immunofluorescently labeled with antibodies to the five classes of intermediate-filament proteins and to desmoplakin. Positive immunoreactivity to keratin and to desmoplakin was observed; both results indicate the epithelial nature of this tissue. The absence of neurofilaments and glialfibrillary acidic protein in the tissue containing sensory neurons and gliallike supporting cells is a unique feature, and may be related to the fact that olfactory neuroepithelium, like other epithelia, undergoes continuous turnover. (Arch Otolaryngol Head Neck Surg 1987;113:155-159) The olfactory mucosa is a discrete region of the nasal mucosa that is specialized for the detection of odorants. It consists of two layers, the superficial olfactory epithelium and the deeper lamina propria. The pseudostratified columnar epithelium con¬ tains three cell types: olfactory senso¬ ry neurons, supporting cells, and basal cells. These cells are characteristical¬ ly arranged in a zonal distribution, with the basal cells found at the lower third of the epithelium, the perikarya of the supporting cells forming the upper third of the epithelium, and the neuron cell bodies located between the basal cells and the supporting cells. The olfactory neuron possesses a peripheral dendrite from which sever¬ al cilia extend into the lumen. These cilia, distinct in their extended length, are modified ciliary structures similar to other sensory organelles, such as rod and cone outer segments in the retina, or hair cell kinocilia in the inner ear, and serve as the site of olfactory transduction.

Purified cultures of keratin‐positive olfactory epithelial cells: Identification of a subset as neuronal supporting (Sustentacular) cells

“…Those which used unfixed tissue sections showed additional staining suggestive of sustentacular cell staining (Ophir, 1987;Ophir and Lancet, 1988). Also, researchers have shown more extensive staining in embryonic mice (Calof and Chikaraishi, 1989) and fetal human olfactory tissues (Ophir, 1987;Ophir and Lancet, 1988). The previously reported results are more consistent in the respiratory epithelium where staining similar to ours has been described in the mouse (Calof and Chikaraishi, 1989), frog (Ophir and Lancet, 1988), bovine (Ophir and Lancet, 1988), guinea pig (Yamagishi et al, 1989) and human (Ophir, 1987;Yamagishi et al, 1989).…”

“…Re-examination of previously published reports shows that those which examined fixed adult tissues demonstrated specific basal cell staining in the mouse (Calof and Chikaraishi, 1989), human, and guinea pig (Yamagishi et al, 1989). Those which used unfixed tissue sections showed additional staining suggestive of sustentacular cell staining (Ophir, 1987;Ophir and Lancet, 1988). Also, researchers have shown more extensive staining in embryonic mice (Calof and Chikaraishi, 1989) and fetal human olfactory tissues (Ophir, 1987;Ophir and Lancet, 1988).…”

“…Also, researchers have shown more extensive staining in embryonic mice (Calof and Chikaraishi, 1989) and fetal human olfactory tissues (Ophir, 1987;Ophir and Lancet, 1988). The previously reported results are more consistent in the respiratory epithelium where staining similar to ours has been described in the mouse (Calof and Chikaraishi, 1989), frog (Ophir and Lancet, 1988), bovine (Ophir and Lancet, 1988), guinea pig (Yamagishi et al, 1989) and human (Ophir, 1987;Yamagishi et al, 1989). Based on tissue section staining, the majority of keratin-positive cells in the olfactory epithelium, and certainly the ones which stain most intensely, are the dark basal cells.…”