Cells Of Olfactory Epithelium Research Articles

Comparative assessment of the role of TMPRSS2 and ACE-2 receptors in the development of olfactory disorders in infection with coronavirus SARS-CoV-2

Background. Today, evidence of the impact of the SARSCoV-2 coronavirus not only on the cells of the olfactory epithelium, but also on the components of the deeper parts of the olfactory system (olfactory bulbs and the olfactory area of the cerebral cortex), indicates the expression of proteins by the cells of the olfactory epithelium that contribute to further penetration of the virus. An urgent problem is the lack of comprehensive studies of the role of morphological and immunological features of various parts of the olfactory system in the occurrence of olfactory disorders and insufficient understanding of the relationship between their duration and the localization of cells affected by the SARS-CoV-2 coronavirus. The оbjective of the study is to clarify the feasibility of studying the role of TMPRSS2 receptors and comparing it with the role of ACE-2 receptors localized on the components of the olfactory epithelium in the development of olfactory disorders in the Coronavirus Disease 2019 caused by SARS-CoV-2. Methods. This study was performed using autopsy material, namely fragments of the mucous membrane of the upper parts of the nasal cavity (olfactory epithelium), obtained from 10 deceased (6 women and 4 men) aged 53 to 79 years with a laboratory-confirmed diagnosis of "Coronavirus Disease 2019" (polymerase chain reaction) and olfactory disorders of various degrees in the anamnesis. Mucosal samples were stained both with hematoxylin and eosin, and using an immunohistochemical method with antibodies to transmembrane serine protease-2 (TMPRSS2) and angiotensin-converting enzyme (ACE-2). Results. As a result of this study, the number of OMP-positive cells in sections of the olfactory epithelium was on average 46.5 in the field of view at 200x magnification (35.0-59.0), ACE-2-positive cells - 38.5 in the field of view at magnification 200x (21.0-55.0), TMPRSS2-positive - 81 in the field of view at 200x magnification (63.0-96.0). Conclusion. Studying the role of TMPRSS2 and ACE-2 receptors localized on olfactory epithelial cells in the development of olfactory disorders in the 2019 coronavirus disease caused by SARS-CoV-2 will provide a better scientific understanding of the development of disease-specific symptoms.

Constitutive and evoked release of ATP in adult mouse olfactory epithelium.

In adult olfactory epithelium (OE), ATP plays a role in constant cell turnover and post-injury neuroregeneration. We previously demonstrated that constitutive and ATP-evoked ATP release are present in neonatal mouse OE and underlie continuous cell turn-over and post-injury neuroregeneration, and that activation of purinergic P2X7 receptors is involved in the evoked release. We hypothesized that both releases are present in adult mouse OE. To study the putative contribution of olfactory sensory neurons to ATP release, we used olfactory sensory neuronal-like OP6 cells derived from the embryonic olfactory placode cells. Calcium imaging showed that OP6 cells and primary adult OE cell cultures express functional purinergic receptors. We monitored ATP release from OP6 cells and whole adult OE turbinates using HEK cells as biosensors and luciferin-luciferase assays. Constitutive ATP release occurs in OP6 cells and whole adult mouse OE turbinates, and P2X7 receptors mediated evoked ATP release occurs only in turbinates. The mechanisms of ATP release described in the present study might underlie the constant cell turn-over and post-injury neuroregeneration present in adult OE and thus, further studies of these mechanisms are warranted as it will improve our knowledge of OE tissue homeostasis and post-injury regeneration.

Assessing the Adverse Impacts of PM2.5 on Olfactory System Using an Air-liquid Interface Culture Model of Primary Olfactory Epithelial Cells

Assessing the Adverse Impacts of PM2.5 on Olfactory System Using an Air-liquid Interface Culture Model of Primary Olfactory Epithelial Cells

Olfactory Regeneration with Nasally Administered Murine Adipose-Derived Stem Cells in Olfactory Epithelium Damaged Mice

In this study, we aimed to determine whether nasally administered murine adipose-derived stem cells (ADSCs) could support olfactory regeneration in vivo. Olfactory epithelium damage was induced in 8-week-old C57BL/6J male mice by intraperitoneal injection of methimazole. Seven days later, OriCell adipose-derived mesenchymal stem cells obtained from green fluorescent protein (GFP) transgenic C57BL/6 mice were nasally administered to the left nostril of these mice, and their innate odor aversion behavior to butyric acid was assessed. Mice showed significant recovery of odor aversion behavior, along with improved olfactory marker protein (OMP) expression on both sides of the upper-middle part of the nasal septal epithelium assessed by immunohistochemical staining 14 d after the treatment with ADSCs compared with vehicle control animals. Nerve growth factor (NGF) was detected in the ADSC culture supernatant, NGF was increased in the nasal epithelium of mice, and GFP-positive cells were observed on the surface of the left side nasal epithelium 24 h after left side nasal administration of ADSCs. The results of this study suggest that the regeneration of olfactory epithelium can be stimulated by nasally administered ADSCs secreting neurotrophic factors, thereby promoting the recovery of odor aversion behavior in vivo.

Molecular Evidence for Olfactory Neuroblastoma as a Tumor of Malignant Globose Basal Cells

Olfactory neuroblastoma (ONB, esthesioneuroblastoma) is a sinonasal cancer with an underdeveloped diagnostic toolkit, and is the subject of many incidents of tumor misclassification throughout the literature. Despite its name, connections between the cancer and normal cells of the olfactory epithelium have not been systematically explored and markers of olfactory epithelial cell types are not deployed in clinical practice. Here, we utilize an integrated human-mouse single-cell atlas of the nasal mucosa, including the olfactory epithelium, to identify transcriptomic programs that link ONB to a specific population of stem/progenitor cells known as olfactory epithelial globose basal cells (GBCs). Expression of a GBC transcription factor NEUROD1 distinguishes both low- and high-grade ONB from sinonasal undifferentiated carcinoma, a potential histologic mimic with a distinctly unfavorable prognosis. Furthermore, we identify a reproducible subpopulation of highly proliferative ONB cells expressing the GBC stemness marker EZH2, suggesting that EZH2 inhibition may play a role in the targeted treatment of ONB. Finally, we study the cellular states comprising ONB parenchyma using single-cell transcriptomics and identify evidence of a conserved GBC transcriptional regulatory circuit that governs divergent neuronal-versus-sustentacular differentiation. These results link ONB to a specific cell type for the first time and identify conserved developmental pathways within ONB that inform diagnostic, prognostic, and mechanistic investigation.

Coronavirus infection in chemosensory cells.

Clinical manifestations of human coronavirus (HCoV)-related diseases are mostly related to the respiratory system, although secondary complications such as headache, anosmia, ageusia, and myalgia have been reported. HCoV infection and replication in chemosensory cells associated with ageusia and anosmia is poorly understood. Here, we characterized HCoV-OC43 and SARS-CoV-2 infection in two types of chemosensory cells, olfactory and taste cells, with their unique molecular and histological characteristics. We first assessed HCoV-OC43 infection in in vitro cultured human olfactory epithelial cells (hOECs) and fungiform taste papilla (HBO) cells. Interestingly, while both cell types were susceptible to HCoV-OC43 infection, viral replication rates were significantly reduced in HBO cells compared to hOECs. More interestingly, while culture media from hOECs was able to produce secondary infection in Vero cells, there was very limited secondary infection from HBO cells, suggesting that HBO cells may not be able to release infectious virus. On the other hand, unlike HCoV-OC43, SARS-CoV-2 showed comparable levels of viral infection rates in both hOECs and HBO cells. Furthermore, our RT-qPCR-based gene array studies revealed that several key genes involved in taste and olfactory functions were significantly altered by SARS-CoV-2 infection. These results may suggest a possible mechanism associated with chemosensory symptoms, such as anosmia and ageusia in patients infected with SARS-CoV-2.

Development of an olfactory epithelial organoid culture system based on small molecule screening

Olfactory epithelium, which detects and transmits odor signals, is critical for the function of olfactory system. Olfactory epithelium is able to recover spontaneously after injury under normal circumstances, but this ability is dampened in certain diseases or senility, which causes olfactory dysfunction. The olfactory epithelium consists of basal cells, sustentacular cells and olfactory sensory neurons. In order to develop an olfactory epithelial organoid containing multiple olfactory cell types in vitro, we used three-dimensional culture model and small molecules screening. This organoid system consists of horizontal basal-like cells, globose basal-like cells, sustentacular-like cells and olfactory sensory neurons-like cells. Through statistical analysis of clone diameter, immunofluorescence staining and qPCR detection of the expression level of related marker genes. We identified a series of growth factors and small molecule compounds that affected the proliferation, composition and gene expression of the organoids. CHIR-99021, an activator of Wnt signaling pathway, increased the colony formation and proliferation rate of olfactory epithelial organoids and the expression level of marker genes of olfactory sensory neurons-like cells. In addition, each factor in the culture system increased the proportion of c-Kit-positive globose basal-like cell colonies in organoids. Moreover, EGF and vitamin C were both beneficial to the expression of horizontal basal-like cell marker genes in organoids. The established olfactory epithelial organoid system mimicked the process of olfactory epithelial stem cells differentiating into various olfactory epithelial cell types, thus providing a research model for studying olfactory epithelial tissue regeneration, the pathological mechanism of olfactory dysfunction and drug screening for olfactory dysfunction treatment.

Identity, lineage and fates of a temporally distinct progenitor population in the embryonic olfactory epithelium

We defined a temporally and transcriptionally divergent precursor cohort in the medial olfactory epithelium (OE) shortly after it differentiates as a distinct tissue at mid-gestation in the mouse. This temporally distinct population of Ascl1+ cells in the dorsomedial OE is segregated from Meis1+/Pax7+ progenitors in the lateral OE, and does not appear to be generated by Pax7+ lateral OE precursors. The medial Ascl1+ precursors do not yield a substantial number of early-generated ORNs. Instead, they first generate additional proliferative precursors as well as a distinct population of frontonasal mesenchymal cells associated with the migratory mass that surrounds the nascent olfactory nerve. Parallel to these in vivo distinctions, isolated medial versus lateral OE precursors in vitro retain distinct proliferative capacities and modes of division that reflect their in vivo identities. At later fetal stages, these early dorsomedial Ascl1+ precursors cells generate spatially restricted subsets of ORNs as well as other non-neuronal cell classes. Accordingly, the initial compliment of ORNs and other OE cell types is derived from at least two distinct early precursor populations: lateral Meis1/Pax7+ precursors that generate primarily early ORNs, and a temporally, spatially, and transcriptionally distinct subset of medial Ascl1+ precursors that initially generate additional OE progenitors and apparent migratory mass cells before yielding a subset of ORNs and likely supporting cell classes.

Primary Culture of the Human Olfactory Neuroepithelium and Utilization for Henipavirus Infection In Vitro.

The olfactory receptor neurons (ORNs) are a unique cell type involved in the initial perception of odors. These specialized epithelial cells are located in the neuroepithelium of the nasal cavities and directly connect the nasal cavity with the central nervous system (CNS) via axons, which traverse the cribriform plate to synapse within the olfactory bulb. ORNs are derived from precursor cells that lie adjacent to the basal lamina of the olfactory epithelium. These precursor cells divide several times and their progeny differentiate into mature sensory neurons throughout life. In addition to its major and critical role in sensory transduction, the olfactory neuroepithelium may be an important tissue for viral replication and represents a potential site for viral entry into the CNS. In general, to gain access to the CNS, neurotropic viruses such as henipaviruses can use peripheral neural pathways or the circulatory system. However, the olfactory system has been reported to provide a portal of entry to the CNS for henipaviruses. The ability to obtain biopsies from living human subjects and culture these cells in the laboratory provides the opportunity to examine viral replication and effects on a neuronal cell population. As the most exposed and unprotected segment of the nervous system, the olfactory neuroepithelium may have an important role in neuropathology and systemic dissemination of viruses with established CNS effects. This chapter presents methods for primary culture of human ORNs, which have been used successfully by multiple investigators. The protocol provides a consistent, heterogeneous olfactory epithelial cell population, which demonstrates functional responses to odorant mixtures and exhibits several key features of the olfactory receptor neuron phenotype, encompassing olfactory receptors and signaling pathways.

Persistent post-COVID-19 smell loss is associated with immune cell infiltration and altered gene expression in olfactory epithelium.

SARS-CoV-2 causes profound changes in the sense of smell, including total smell loss. Although these alterations are often transient, many patients with COVID-19 exhibit olfactory dysfunction that lasts months to years. Although animal and human autopsy studies have suggested mechanisms driving acute anosmia, it remains unclear how SARS-CoV-2 causes persistent smell loss in a subset of patients. To address this question, we analyzed olfactory epithelial samples collected from 24 biopsies, including from nine patients with objectively quantified long-term smell loss after COVID-19. This biopsy-based approach revealed a diffuse infiltrate of T cells expressing interferon-γ and a shift in myeloid cell population composition, including enrichment of CD207+ dendritic cells and depletion of anti-inflammatory M2 macrophages. Despite the absence of detectable SARS-CoV-2 RNA or protein, gene expression in the barrier supporting cells of the olfactory epithelium, termed sustentacular cells, appeared to reflect a response to ongoing inflammatory signaling, which was accompanied by a reduction in the number of olfactory sensory neurons relative to olfactory epithelial sustentacular cells. These findings indicate that T cell-mediated inflammation persists in the olfactory epithelium long after SARS-CoV-2 has been eliminated from the tissue, suggesting a mechanism for long-term post-COVID-19 smell loss.

Long COVID: The latest manifestations, mechanisms, and potential therapeutic interventions.

COVID-19 caused by SARS-CoV-2 infection affects humans not only during the acute phase of the infection, but also several weeks to 2 years after the recovery. SARS-CoV-2 infects a variety of cells in the human body, including lung cells, intestinal cells, vascular endothelial cells, olfactory epithelial cells, etc. The damages caused by the infections of these cells and enduring immune response are the basis of long COVID. Notably, the changes in gene expression caused by viral infection can also indirectly contribute to long COVID. We summarized the occurrences of both common and uncommon long COVID, including damages to lung and respiratory system, olfactory and taste deficiency, damages to myocardial, renal, muscle, and enduring inflammation. Moreover, we provided potential treatments for long COVID symptoms manifested in different organs and systems, which were based on the pathogenesis and the associations between symptoms in different organs. Importantly, we compared the differences in symptoms and frequency of long COVID caused by breakthrough infection after vaccination and infection with different variants of concern, in order to provide a comprehensive understanding of the characteristics of long COVID and propose improvement for tackling COVID-19.

RNAseq analysis of olfactory neuroepithelium cytological samples in individuals with Down syndrome compared to euploid controls: a pilot study

Down syndrome is a common genetic disorder caused by partial or complete triplication of chromosome 21. This syndrome shows an overall and progressive impairment of olfactory function, detected early in adulthood. The olfactory neuronal cells are located in the nasal olfactory mucosa and represent the first sensory neurons of the olfactory pathway. Herein, we applied the olfactory swabbing procedure to allow a gentle collection of olfactory epithelial cells in seven individuals with Down syndrome and in ten euploid controls. The aim of this research was to investigate the peripheral gene expression pattern in olfactory epithelial cells through RNAseq analysis. Validated tests (Sniffin’ Sticks Extended test) were used to assess olfactory function. Olfactory scores were correlated with RNAseq results and cognitive scores (Vineland II and Leiter scales). All Down syndrome individuals showed both olfactory deficit and intellectual disability. Down syndrome individuals and euploid controls exhibited clear expression differences in genes located in and outside the chromosome 21. In addition, a significant correlation was found between olfactory test scores and gene expression, while a non-significant correlation emerged between olfactory and cognitive scores. This first preliminary step gives new insights into the Down syndrome olfactory system research, starting from the olfactory neuroepithelium, the first cellular step on the olfactory way.Graphical

The respiratory exercise significance in the olfaction restoration in the postcovid period

One of the pathognomonic COVID‑19 signs, occurring in 85‑98% of patients, is olfactory dysfunction, developing in the absence of pronounced inflammation and edema of the nasal mucosa. A promising medicine direction that helps restore microcirculation, increase blood oxygenation, improve metabolism and regenerate olfactory epithelial cells is the Nadi Shodhana breathing exercise technique.Objective: To assess the possibilities of using the pranayama technique as a method of restorative olfactory treatment in the post‑covid period.Materials and methods: 79 persons aged 22 to 68 years with olfactory disturbances occurring at COVID‑19 and persisting in the post‑covid period were examined. As a restorative treatment for olfactory disorders, the patients of the main group were offered a course of Nadi Shodhana breathing exercises, which is an alternate nostril breathing. Breathing training consisted of three such cycles performed three times a day at the same time for 15 days. The possibility of using the pranayama technique was assessed according to the visual analog scale. The control group consisted of 74 patients with olfactory disorders after COVID‑19 comparable in sex and age with the main group.Results: Olfactory disorders are characteristic of post‑COVID patients. Using Nadi Shodhana breathing exercise course can significantly reduce the olfactory dysfunction level in this patient category. It was showen that the pranayama technique is more effective in people under 40 years of age. It was also established that the olfaction restoration largely depends on the duration of the dysfunction period.Conclusion: The study results make it possible to recommend the using breathing exercises in patients underwent COVID‑19 to restore olfaction in the post‑COVID period.

Modeling Infection and Tropism of Human Parainfluenza Virus Type 3 in Ferrets.

ABSTRACTHuman parainfluenza virus type 3 (HPIV-3) is a significant cause of lower respiratory tract infections, with the most severe disease in young infants, immunocompromised individuals, and the elderly. HPIV-3 infections are currently untreatable with licensed therapeutics, and prophylactic and therapeutic options are needed for patients at risk. To complement existing human airway models of HPIV-3 infection and develop an animal model to assess novel intervention strategies, we evaluated infection and transmission of HPIV-3 in ferrets. A well-characterized human clinical isolate (CI) of HPIV-3 engineered to express enhanced green fluorescent protein (rHPIV-3 CI-1-EGFP) was passaged on primary human airway epithelial cells (HAE) or airway organoids (AO) to avoid tissue culture adaptations. rHPIV3 CI-1-EGFP infection was assessed in vitro in ferret AO and in ferrets in vivo. Undifferentiated and differentiated ferret AO cultures supported rHPIV-3 CI-1-EGFP replication, but the ferret primary airway cells from AO were less susceptible and permissive than HAE. In vivo rHPIV-3 CI-1-EGFP replicated in the upper and lower airways of ferrets and targeted respiratory epithelial cells, olfactory epithelial cells, type I pneumocytes, and type II pneumocytes. The infection efficiently induced specific antibody responses. Taken together, ferrets are naturally susceptible to HPIV-3 infection; however, limited replication was observed that led to neither overt clinical signs nor ferret-to-ferret transmission. However, in combination with ferret AO, the ferret model of HPIV-3 infection, tissue tropism, and neutralizing antibodies complements human ex vivo lung models and can be used as a platform for prevention and treatment studies for this important respiratory pathogen.

SARS-CoV-2 susceptibility of domestic and wild mammals: is it all about the similarity of their ACE2 receptor to the human one?

You have accessMoreSectionsView PDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmail Cite this article Di Guardo Giovanni 2022SARS-CoV-2 susceptibility of domestic and wild mammals: is it all about the similarity of their ACE2 receptor to the human one?Proc. R. Soc. B.2892021256020212560http://doi.org/10.1098/rspb.2021.2560SectionYou have accessCommentSARS-CoV-2 susceptibility of domestic and wild mammals: is it all about the similarity of their ACE2 receptor to the human one? Giovanni Di Guardo† Giovanni Di Guardo http://orcid.org/0000-0003-4592-1084 Retired Professor of General Pathology and Veterinary Pathophysiology, Veterinary Medical Faculty, University of Teramo, Località Piano d'Accio, 64100 Teramo, Italy [email protected] Contribution: Writing – original draft Google Scholar Find this author on PubMed Search for more papers by this author Giovanni Di Guardo† Giovanni Di Guardo http://orcid.org/0000-0003-4592-1084 Retired Professor of General Pathology and Veterinary Pathophysiology, Veterinary Medical Faculty, University of Teramo, Località Piano d'Accio, 64100 Teramo, Italy [email protected] Contribution: Writing – original draft Google Scholar Find this author on PubMed Search for more papers by this author Published:02 February 2022https://doi.org/10.1098/rspb.2021.2560This article comments on the following:Research ArticlePredicting the zoonotic capacity of mammals to transmit SARS-CoV-2https://doi.org/10.1098/rspb.2021.1651 Ilya R. Fischhoff, Adrian A. Castellanos, João P. G. L. M. Rodrigues, Arvind Varsani and Barbara A. Han volume 288issue 1963Proceedings of the Royal Society B: Biological Sciences17 November 2021I read with great interest the article by Dr Ilya Fischhoff and co-workers, in which an elegant machine learning-based approach was successfully employed to predict the susceptibility of mammals to severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2), along with the zoonotic hazard posed by them. The three-dimensional model described by the aforementioned colleagues enabled prediction of the zoonotic potential of SARS-CoV-2 for more than 5000 domestic and wild mammals, with the obtained predictions being additionally corroborated by in vivo studies [1]. One of the main reasons underlying this work was represented by the comparatively much fewer mammalian species for which the primary amino acid sequences of their angiotensin-converting enzyme 2 (ACE2) viral host cell receptor are currently available.In this respect, however, adequate emphasis should be also placed upon the fact that a number of discrepancies have been reported between ACE2-expressing cells, on one side, and tissue tropism of SARS-CoV-2, on the other, with very low ACE2 expression levels having been found in respiratory and olfactory epithelial cells, despite their extremely frequent, if not constant, targeting by this viral pathogen [2].Noteworthy, two independent studies published in November 2020 in Science have shown that neuropilin-1 (NRP1), which is consistently expressed by respiratory, olfactory epithelial and endothelial cells, binds (similarly to ACE2) the furin-cleaved S1 fragment of SARS-CoV-2 spike glycoprotein, thereby potentiating infectivity and allowing viral entry into host cells [3,4]. This could also explain why a number of viruses such as human T-cell lymphotropic virus type 1 [5] and Epstein–Barr virus [6] use NRP1 for gaining entrance into susceptible host cells, given its high expression on epithelia facing the external environment and its role in enabling cell, vascular and tissue colonization.Within this framework, it would be interesting to comparatively investigate if and to what extent the different body cells and tissues from humans as well as from a number of SARS-CoV-2-susceptible mammals—either naturally/experimentally or suspectedly, based upon the herein commented machine learning approach [1]—express ACE2 and NRP1 simultaneously. Furthermore, the comparative study of the degree of primary amino acid sequence homology between human and animal ACE2 and NRP1 viral host cell receptors/coreceptors would probably clarify the SARS-CoV-2 susceptibility of the different species under investigation. This, in turn, could also allow a given animal species to act as a potentially valuable model in the comparative pathogenetic study of human SARS-CoV-2 infection, thus elucidating past and future ‘trajectories’ of this threatening viral agent, with special emphasis on its origin and on its ‘spillovers and spillbacks' from animals to mankind (and vice versa).Data accessibilityThis article has no additional data.Authors' contributionsG.D.G.: writing—original draft.Competing interestsI declare I have no competing interests.FundingI received no funding for this study.Footnotes†Present address: Viale Pasteur 77, 00144 EUR Rome, Italy.© 2022 The Author(s)Published by the Royal Society. All rights reserved.

Anosmia as a clinical predictor to non-fatal COVID-19 case and better survivability

Recently, a respiratory infectious disease labeled as COVID-19 caused by SARS-CoV-2 had taken over the world by storm. This RNA virus can cause various symptoms such as malaise, anosmia, ageusia, fever, cough, headache, myalgia, diarrhea, and ARDS. COVID-19 patients have specific symptoms such as fever. In another study, it was said that anosmia could be a benchmark for screening for COVID-19. in a study of young patients and was more common in women. The average onset of anosmia occurs on day 4 after infection and lasts for 8 days. the evidence says that this disease can cause a decrease in a person's quality of life. The exact cause of anosmia is still unknown, but several theories suggest that anosmia can occur due to damage to nerve receptors, inflammation of olfactory epithelial cells, and dysfunction of nerve receptors. The popular theory is that anosmia occurs due to inflammation of the olfactory epithelial cells, thereby damaging the olfactory receptors. The inflammation blocks odors from reaching the nasal mucosa and can inhibit receptor excitability and signal transduction. Anosmia may be associated with lower hospital mortality rates. However, further research and discovery is needed to fully grasp the pathophysiological concept of COVID-19 induced anosmia. This review will discuss the pathophysiology and review the lower anosmia mortality rate. This article reviews current understandings about the pathophysiology of anosmia and its potential as a marker towards better clinical prognosis. This narrative review aims to provide knowledge about updates regarding the pathophysiology of anosmia as a clinical predictor of mild and severe COVID-19 symptoms.

Effect of Mancozeb Inhalation on the Olfactory Mucosa in Rats

Background: Mancozeb, (ethylene-bis-dithiocarbamate), is an important fungicide useful against a wide range of fungus affecting ornamental plants, crops, and fruits. We aimed to evaluate the changes in the olfactory mucosa due to mancozeb toxicity and, if cytokine is active, IL-6 immunoactivity. Material and Method: In experimental group, the mancozeb (500 mg/kg) was administered with inhalation to 10 male Wistar Albino rats for five days a week. The control group (n = 10) received distilled water with spray at the same time period. The experiment was terminated after three weeks. Samples were placed in 10% formaldehyde for fixation and placed in paraffin, sections of 5 μm were prepared from paraffin blocks and stained with Hematoxylin-Eosin. Interleukin-6 (IL-6) primary antibody were used for immunohistochemical analysis. Result: In the mancozeb group, olfactory epithelial cell degeneration and apoptosis, inflammation, dilatation and congestion in the vessels were observed. IL-6 expression was increased in vascular endothelium and inflammatory cells. Conclusions: Mancozeb was thought that the increase in IL-6 expression due to the increase in cell degeneration signal was thought to affect the development of cell apoptosis and angiogenesis, and that the use of mancozeb might adversely affect the olfactory mechanism.

Effect of inhalation of different-concentrations of moxa smoke on apoptosis and regeneration of olfactory epithelial cells in rats

To observe the effect of long-term inhalation of moxa-smoke on olfactory epithelial cells in rats, in order to explore the safety of moxa-smoke inhalation (MSI). A total of 32 SD rats (half male and half female) were randomly divided into 4 groups: normal, low concentration (LCMSI), medium concentration (MCMSI) and high concentration (HCMSI), with 8 rats in each group. Rats of the LCMSI, MCMSI and HCMSI groups were put into closed boxes which were filled with ignited moxa stick-released smoke at concentrations of (0.11±0.05)mg/m3, (0.23±0.05) mg/m3 and (0.53±0.05)mg/m3, respectively. The treatment was given 4 h each time, twice a day for 90 days. Rats of the normal group were fed routinely. The rats' general state and behavior (including fur appearance, activities in cage, response to external stimuli, spirit, stool, diet and water drinking) were recorded, and the olfactory function was assessed by using latency of finding the buried food pellet (BFP) test. The number of apoptotic olfactory epithelial cells was counted after terminal labeling (TUNEL), and the proliferation of basal cells of the nasal mucosa was detected by BrdU incorporation immunohistochemical technique. The latency of BFP was significantly longer in the MCMSI and HCMSI groups than in the normal and LCMSI groups (P<0.01), and had no significant differences between the LCMSI and normal groups, and between the MCMSI and HCMSI groups (P>0.05). The numbers of the apoptotic olfactory epithelial cells and proliferative basal cell in the nasal mucus tissue were markedly more in the LCMSI, MCMSI and HCMSI groups than in the normal group (P<0.01, P<0.05), and obviously more in the MCMSI and HCMSI groups than in the LMCMSI group (P<0.01), and apparently more in the HCMSI group than in the MCMSI group (P<0.01). The general state observation showed that in the first 45 days, only yellowish fur and water intake increase were seen in rats of the 3 moxa smoke inhalation groups, while no obvious changes in rats of the LCMSI group, and decrease in activities, being sensitive to external stimulation and fiddle-footed, and lower spirit in rats of the MCMSI and HCMSI groups in comparison with rats of the normal group after 90 day's MSI. Long-term inhalation of medium and high concentrations of moxa smoke may cause a reduction of the olfactory sensitivity and an increase of apoptosis of olfactory epithelial cells and proliferation of basal cells.

Effect of copper nanoparticles and copper ions on the architecture of rainbow trout olfactory mucosa

Olfactory epithelial cells are in direct contact with myriad environmental contaminants which may consequently disrupt their structure and function. Copper ions (Cu2+) and copper nanoparticles (CuNPs) are two types of olfactory neurotoxicants. However, their effects on the structure of olfactory epithelium are largely uninvestigated. The density of olfactory goblet cells in CuNP- and Cu2+ - exposed rainbow trout was assessed using light microscopy throughout time. In both copper (Cu) treatments, the number of goblet cells increased initially over the 24 h exposure and then recovered to normal throughout the 96 h exposure. These data suggested the 96 h exposure to Cu contaminants interfered with protective barrier provided by goblet cells. Nonetheless, lamellar and epithelial thickness of olfactory rosette did not change in the Cu-exposed fish. The gene transcript profile of olfactory mucosa studied by RNA-seq indicated Cu2+ and CuNPs differentially targeted the molecular composition of cell junctions. In the Cu2+ treatment, reduced mRNA abundances of tight junctions, adherens junction, desmosomes and hemidesmosomes, suggest that Cu2+-exposed olfactory mucosal cells had weak junctional complexes. In the CuNP treatment, on the other hand, the transcript abundances of cell junction compositions, except adherens junction, were upregulated. Transcripts associated with gap junctional channels were increased in both Cu treatments. The elevated transcript levels of gap junctions in both Cu treatments suggested that the demand for intercellular communication was increased in the Cu-exposed olfactory mucosa. Overall, our findings suggested that Cu2+ induced greater adverse effects on the molecular composition of olfactory cell junctions relative to CuNPs. Impairment of junctional complexes may disrupt the structural integrity of olfactory mucosa.

Effect of different concentrations of moxa smoke exposure on nasal mucosal injury and expression of serum IL-1, IL-6 and TNF-α in rats

To observe the effect of long-term moxa smoke exposure of different concentrations on olfactory function in rats, and provide experimental basis of safety study of moxa smoke produced by moxibustion. Forty SD rats were randomly divided into a normal control group, a low-concentration moxa smoke group, a moderate-concentration moxa smoke group and a high-concentration moxa smoke group, 10 rats in each one. The rats in the moxa smoke groups were put into three plexiglass moxibustion boxes with different moxa smoke concentrations, 4 hours per times, twice a day for 90 days. The general state of rats was evaluated before and during the experiment. After the intervention, the olfactory function was evaluated by two-bottle experiment (TBE); the morphology of nasal mucosa was observed by HE staining; the apoptosis of olfactory epithelial cells in nasal mucosa was detected by TUNEL method; the serum levels of interleukin-1 (IL-1), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were detected by ELISA method. In the late stage of moxa smoke exposure (45-90 days into intervention), the behavioral activity of rats in the moderate-concentration moxa smoke group and the high-concentration moxa smoke group was weaker than that in the normal control group, and their response to stimulation was strong, and their mental state was worse. After intervention, the drinking rate of vinegar-water mixture in the moderate-concentration moxa smoke group and the high-concentration moxa smoke group was higher than that in the normal control group and the low-concentration moxa smoke group (P<0.01). The hierarchical structure of nasal mucosa in the moderate-concentration moxa smoke group and the high-concentration moxa smoke group was unclear, disordered, necrotic and inflammatory cell infiltration was serious; the number of apoptotic cells in olfactory epithelium of nasal mucosa in the moderate-concentration moxa smoke group and the high-concentration moxa smoke group was more than that in the normal control group and the low-concentration moxa smoke group (P<0.01), that in the high-concentration moxa smoke group was more than the moderate-concentration group (P<0.01). The serum levels of IL-1, IL-6 and TNF-α in the low-concentration moxa smoke group, the moderate-concentration moxa smoke group and the high-concentration moxa smoke group were higher than the normal control group (P<0.01), and those in the moderate-concentration moxa smoke group and the high-concentration moxa smoke group were higher than the low-concentration moxa smoke group (P<0.01), and those in the high-concentration moxa smoke group were higher than moderate-concentration moxa smoke group (P<0.01). The long-term exposure to low, moderate and high concentrations of moxa smoke could cause pathological changes in nasal mucosa and increase the serum levels of IL-1, IL-6 and TNF-α; the moderate and high concentrations of moxa smoke exposure could cause a series of damage to olfactory function and reduce olfactory sensitivity in rats.