Neuroendocrinelike (small granule) epithelial cells of the lung.

Abstract

The presence of neuroendocrinelike epithelial cells in the lung of numerous species has been demonstrated by light and electron microscopy. Histochemical methods used to identify these cells have included staining with silver, amine-type fluorescence (APUD cell), periodic acid Schiff (PAS)-lead hematoxylin, and immunohistochemical localization of neuron-specific enolase. Cytoplasmic dense core vesicles (70-200 nm in diameter) have served as the major ultrastructural characteristic. Lung neuroendocrinelike cells have been shown to occur in fetal and adult mammals as solitary-type cells or as distinct organoids known as neuroepithelial bodies ( NEBs ). Although the frequency of both populations is considered low, solitary-type cells with dense-core granules can be found in as high as 5% of epithelial cells in the cricoid region of the guinea-pig larynx. The solitary cells can be found throughout the airways of mammals, whereas the NEBs are confined to the intrapulmonary airways. Unmyelinated fibers have been traced from the lamina propria and into the NEB, where they ramified between the component cells of the NEB. The function of lung neuroendocrinelike cells is not known, but morphological and cytochemical studies suggest that the NEBs are intrapulmonary chemoreceptors that can respond to changes in airway gas composition. Hypoxia or hypercapnia has been shown to decrease the amine cytofluorescence in these organoids and apparently to increase the exocytosis of dense core vesicles from the basal region of the cell. Immunohistochemical studies have suggested that some lung epithelial cells may contain a known neuropeptide(s), but further investigation is needed to confirm the presence of such compounds in lung neuroendocrinelike cells and their physiochemical properties. Apparent hyperplasia of lung neuroendocrinelike cells can occur readily in hamsters treated with diethylnitrosamine. It has been postulated that human lung tumors with endocrinelike properties, namely, bronchial carcinoids and lung small cell carcinomas, may originate from lung neuroendocrinelike cells. However, a more plausible explanation, based on cytokinetic studies of epithelial neuroendocrinelike cells in the lung and other organs, is that these cells originate from a nonneuroendocrine population. Interaction of such a progenitor cell population with selected carcinogens may lead to stimulation of the rate of normal differentiation or, alternately, to selection of an abnormal route of differentiation that possesses a neuroendocrine phenotype. Images FIGURE 1. FIGURE 2. FIGURE 3. FIGURE 4. FIGURE 5. FIGURE 6. FIGURE 7. FIGURE 8. FIGURE 9. FIGURE 10. FIGURE 11. FIGURE 12. FIGURE 13. FIGURE 14. FIGURE 15.

Pulmonary neuroendocrine cells sense succinate to stimulate myoepithelial cell contraction

“…They had a unique morphology with a central flask-shaped cell body containing the nucleus and single or multiple long, narrow branches that contacted the luminal surface or traveled around and beneath surrounding cells ( Figure 1E ). Consistent with previous studies of PNECs, we found rare cells in SMGs that had dense core vesicles, which are typical neuroendocrine features of PNECs ( Figure 1F ) ( DiAugustine and Sonstegard, 1984 ; Yeger et al, 1996 ). SMG PNECs were also enriched for neurotransmitters and neuropeptides previously reported for PNECs, including calcitonin gene-related peptide (CGRP, the protein of CALCA and CALCB ) and serotonin (5-HT) ( Noguchi et al, 2020 ; Xu et al, 2020 ) ( Figures S1D - S1F ).…”

Silsesquioxane polymer as a potential scaffold for laryngeal reconstruction

“…It has six linked cartilages, a finely controlled array of small muscles and delicate neurovascular supply [ 10 ]. Microscopically, the larynx has ciliated [ 11 ], goblet [ 12 ], brush [ 13 ], small granule [ 14 ] and basal [ 15 ] cells. Damage to any part of this complex structure can affect more than one critical function so its repair is not a simple task, often necessitating choosing one activity to preserve at the expense of the others.…”

Amniotic Sac Infection Syndrome Features Fetal Lung Neuroendocrine Cell Hyperfunction

“…Thin tapering processes extend towards the lumen but do not always reach it within the plane of section [14]. NEC receive vagal innervation; the latter precedes the development of the former by several generations of branching [15,16]. Adult human lung NEC contain gastrin-releasing peptide (the mammalian counterpart of bombesin), calcitonin, leu-enkephalin, and serotonin [17].…”

“…Bronchopulmonary NEC are assumed to have paracrine regulatory functions in the fetus [22,23]. Experimental studies have indicated that NEB are indeed intrapulmonary chemoreceptors sensitive to changes in airway gas composition [15], acting via the central nervous system and/or by direct local modulation [24]. With a nerve supply, they could conceivably act as chemoreceptors for respiratory gases, perhaps playing a part in the pulmonary vasoconstrictor [14] and bronchoconstrictor [25] response to hypoxia.…”