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Stark R. The olfactory bulb: A neuroendocrine spotlight on feeding and metabolism. J Neuroendocrinol 2024; 36:e13382. [PMID: 38468186 DOI: 10.1111/jne.13382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 02/22/2024] [Accepted: 02/25/2024] [Indexed: 03/13/2024]
Abstract
Olfaction is the most ancient sense and is needed for food-seeking, danger protection, mating and survival. It is often the first sensory modality to perceive changes in the external environment, before sight, taste or sound. Odour molecules activate olfactory sensory neurons that reside on the olfactory epithelium in the nasal cavity, which transmits this odour-specific information to the olfactory bulb (OB), where it is relayed to higher brain regions involved in olfactory perception and behaviour. Besides odour processing, recent studies suggest that the OB extends its function into the regulation of food intake and energy balance. Furthermore, numerous hormone receptors associated with appetite and metabolism are expressed within the OB, suggesting a neuroendocrine role outside the hypothalamus. Olfactory cues are important to promote food preparatory behaviours and consumption, such as enhancing appetite and salivation. In addition, altered metabolism or energy state (fasting, satiety and overnutrition) can change olfactory processing and perception. Similarly, various animal models and human pathologies indicate a strong link between olfactory impairment and metabolic dysfunction. Therefore, understanding the nature of this reciprocal relationship is critical to understand how olfactory or metabolic disorders arise. This present review elaborates on the connection between olfaction, feeding behaviour and metabolism and will shed light on the neuroendocrine role of the OB as an interface between the external and internal environments. Elucidating the specific mechanisms by which olfactory signals are integrated and translated into metabolic responses holds promise for the development of targeted therapeutic strategies and interventions aimed at modulating appetite and promoting metabolic health.
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Affiliation(s)
- Romana Stark
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
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2
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Kılıçarslan O, Çebi AY, Uçar D. Retinal nerve fiber layer thickness and peripapillary vasculature of post-COVID-19 patients with and without olfactory/gustatory dysfunction symptoms. Taiwan J Ophthalmol 2024; 14:102-107. [PMID: 38654983 PMCID: PMC11034685 DOI: 10.4103/tjo.tjo-d-22-00065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 12/06/2022] [Indexed: 04/26/2024] Open
Abstract
PURPOSE We aimed to compare retinal nerve fiber layer (RNFL) thickness and peripapillary vessel density values between COVID-19 patients with or without olfactory/gustatory dysfunction symptoms and healthy controls. MATERIALS AND METHODS We evaluated RNFL and radial peripapillary capillary vessel density (RPC-VD) values of 41 patients who had COVID-19 history and age- and gender-matched control group including 31 healthy individuals with optical coherence tomography angiography. First, post-COVID-19 group's and control group's RNFL and RPC-VD values were compared, then post-COVID-19 patients were divided into subgroups according to the presence (subgroup-A) and absence (subgroup-B) of olfactory/gustatory dysfunction symptoms, and same parameters were analyzed for subgroups. RESULTS Forty-one eyes of 41 post-COVID-19 patients and 31 eyes of 31 age- and gender-matched healthy controls were included in this cross-sectional study. In RNFL analysis, inferior sector thickness was found significantly lower in post-COVID-19 patients by comparison with control group (P = 0.041). In subgroup analyses, COVID-19 patients who first presented with olfactory/gustatory dysfunction symptoms had higher peripapillary and whole image optic disc capillary density (P = 0.011 and P = 0.002) compared to those who had not had these symptoms. CONCLUSION Lower RPC-VD and RNFL thickness were detected in COVID-19 patients compared to healthy controls. Higher Disc-VD values were found in COVID-19 patients with chemosensorial dysfunction (CSD) symptoms compared to those who had not had these symptoms probably due to milder disease course in COVID-19 with CSD. Sectorial RNFL attenuation in COVID-19 might have occurred secondary to peripapillary capillary circulation defect.
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Affiliation(s)
| | | | - Didar Uçar
- Department of Ophthalmology, Istanbul University-Cerrahpasa, Cerrahpasa Medical Faculty, Istanbul, Turkey
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3
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Hummel T, Power Guerra N, Gunder N, Hähner A, Menzel S. Olfactory Function and Olfactory Disorders. Laryngorhinootologie 2023; 102:S67-S92. [PMID: 37130532 PMCID: PMC10184680 DOI: 10.1055/a-1957-3267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The sense of smell is important. This became especially clear to patients with infection-related olfactory loss during the SARS-CoV-2 pandemic. We react, for example, to the body odors of other humans. The sense of smell warns us of danger, and it allows us to perceive flavors when eating and drinking. In essence, this means quality of life. Therefore, anosmia must be taken seriously. Although olfactory receptor neurons are characterized by regenerative capacity, anosmia is relatively common with about 5 % of anosmic people in the general population. Olfactory disorders are classified according to their causes (e. g., infections of the upper respiratory tract, traumatic brain injury, chronic rhinosinusitis, age) with the resulting different therapeutic options and prognoses. Thorough history taking is therefore important. A wide variety of tools are available for diagnosis, ranging from short screening tests and detailed multidimensional test procedures to electrophysiological and imaging methods. Thus, quantitative olfactory disorders are easily assessable and traceable. For qualitative olfactory disorders such as parosmia, however, no objectifying diagnostic procedures are currently available. Therapeutic options for olfactory disorders are limited. Nevertheless, there are effective options consisting of olfactory training as well as various additive drug therapies. The consultation and the competent discussion with the patients are of major importance.
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Affiliation(s)
- T Hummel
- Interdisziplinäres Zentrum Riechen und Schmecken, HNO Klinik, TU Dresden
| | - N Power Guerra
- Rudolf-Zenker-Institut für Experimentelle Chirurgie, Medizinische Universität Rostock, Rostock
| | - N Gunder
- Universitäts-HNO Klinik Dresden, Dresden
| | - A Hähner
- Interdisziplinäres Zentrum Riechen und Schmecken, HNO Klinik, TU Dresden
| | - S Menzel
- Interdisziplinäres Zentrum Riechen und Schmecken, HNO Klinik, TU Dresden
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4
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Takayama S, Arita R, Ono R, Saito N, Suzuki S, Kikuchi A, Ohsawa M, Tadano Y, Akaishi T, Tanaka J, Kanno T, Abe M, Onodera K, Ishii T. Treatment of COVID-19-Related Olfactory Disorder Promoted by Kakkontokasenkyushin'i: A Case Series. TOHOKU J EXP MED 2021; 254:71-80. [PMID: 34108344 DOI: 10.1620/tjem.254.71] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Olfactory disorders are one of the characteristic symptoms of the coronavirus disease of 2019 (COVID-19), which causes infection and inflammation of the upper and lower respiratory tract. To our knowledge, there are no treatments for COVID-19-related olfactory disorder. Here, we report five olfactory disorder cases in COVID-19, treated using the Japanese traditional (Kampo) medicine, kakkontokasenkyushin'i. We treated five patients with mild COVID-19 at an isolation facility using Kampo medicine, depending on their symptoms. Patients with the olfactory disorder presented with a blocked nose, nasal discharge or taste impairment. Physical examination using Kampo medicine showed similar findings, such as a red tongue with red spots and sublingual vein congestion, which presented as blood stasis and inflammation; thus, we prescribed the Kampo medicine, kakkontokasenkyushin'i. After administration, the numeric rating scale scores of the smell impairment improved within 3 days from 9 to 3 in case 1, from 10 to 0 in case 2, from 9 to 0 in case 3, from 5 to 0 in case 4, and from 9 to 0 within 5 days in case 5. Following the treatment, other common cold symptoms were also alleviated. Kakkontokasenkyushin'i can be used for treating nasal congestion, rhinitis, and inflammation in the nasal mucosa. The olfactory disorder in COVID-19 has been reportedly associated with inflammation and congestion, especially in the olfactory bulb and olfactory cleft. Kakkontokasenkyushin'i may be one of the treatment alternatives for the olfactory disorder with rhinitis in patients with COVID-19.
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Affiliation(s)
- Shin Takayama
- Department of Kampo Medicine, Tohoku University Hospital.,Department of Education and Support for Regional Medicine, Tohoku University Hospital.,Department of Kampo and Integrative Medicine, Tohoku University Graduate School of Medicine
| | - Ryutaro Arita
- Department of Kampo Medicine, Tohoku University Hospital.,Department of Education and Support for Regional Medicine, Tohoku University Hospital
| | - Rie Ono
- Department of Kampo Medicine, Tohoku University Hospital.,Department of Education and Support for Regional Medicine, Tohoku University Hospital
| | - Natsumi Saito
- Department of Kampo Medicine, Tohoku University Hospital.,Department of Education and Support for Regional Medicine, Tohoku University Hospital
| | - Satoko Suzuki
- Department of Kampo Medicine, Tohoku University Hospital.,Department of Education and Support for Regional Medicine, Tohoku University Hospital
| | - Akiko Kikuchi
- Department of Kampo Medicine, Tohoku University Hospital.,Department of Education and Support for Regional Medicine, Tohoku University Hospital.,Department of Kampo and Integrative Medicine, Tohoku University Graduate School of Medicine
| | - Minoru Ohsawa
- Department of Kampo Medicine, Tohoku University Hospital.,Department of Education and Support for Regional Medicine, Tohoku University Hospital.,Department of Kampo and Integrative Medicine, Tohoku University Graduate School of Medicine
| | - Yasunori Tadano
- Department of Education and Support for Regional Medicine, Tohoku University Hospital
| | - Tetsuya Akaishi
- Department of Education and Support for Regional Medicine, Tohoku University Hospital
| | - Junichi Tanaka
- Department of Education and Support for Regional Medicine, Tohoku University Hospital
| | - Takeshi Kanno
- Department of Education and Support for Regional Medicine, Tohoku University Hospital
| | - Michiaki Abe
- Department of Education and Support for Regional Medicine, Tohoku University Hospital
| | - Ko Onodera
- Department of Education and Support for Regional Medicine, Tohoku University Hospital
| | - Tadashi Ishii
- Department of Kampo Medicine, Tohoku University Hospital.,Department of Education and Support for Regional Medicine, Tohoku University Hospital.,Department of Kampo and Integrative Medicine, Tohoku University Graduate School of Medicine
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5
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Altundag A, Saatci O, Sanli DET, Duz OA, Sanli AN, Olmuscelik O, Temirbekov D, Kandemirli SG, Karaaltin AB. The temporal course of COVID-19 anosmia and relation to other clinical symptoms. Eur Arch Otorhinolaryngol 2021; 278:1891-1897. [PMID: 33237475 PMCID: PMC7686554 DOI: 10.1007/s00405-020-06496-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 11/10/2020] [Indexed: 02/08/2023]
Abstract
OBJECTIVE This study aimed to define the clinical course of anosmia in relation to other clinical symptoms. METHODS 135 patients with COVID-19 were reached by phone and subsequently included in the study. Olfactory functions were evaluated using a questionnaire for assessment of self-reported olfactory function. Patients were divided into four subgroups according to the presence of olfactory symptoms and temporal relationship with the other symptoms: group1 had only olfactory complaints (isolated, sudden-onset loss of smell); group2 had sudden-onset loss of smell, followed by COVID-19 related complaints; group3 initially had COVID-19 related complaints, then gradually developed olfactory complaints; and group4 had no olfactory complaints. RESULTS In total, 59.3% of the patients interviewed had olfactory complaints during the disease course. The olfactory dysfunction severity during COVID-19 infection was significantly higher in group1 compared to groups 2 and 3. In groups1-3, the odor scores after recovery from COVID-19 disease were significantly lower compared to the status prior to disease onset. The residual olfactory dysfunction was similar between groups1 and 2, but was more evident than group3. Mean duration for loss of smell was 7.8 ± 3.1 (2-15) days. Duration of loss of smell was longer in groups1 and 2 than in group3. Odor scores completely returned back to the pre-disease values in 41 (51.2%) patients with olfactory dysfunction. Rate of complete olfactory dysfunction recovery was higher in group3 compared to groups1 and 2. CONCLUSION In isolated anosmia cases, anosmia is more severe, and complete recovery rates are lower compared to the patients who have other clinical symptoms. LEVEL OF EVIDENCE Level 4.
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Affiliation(s)
- Aytug Altundag
- Department of Otorhinolaryngology, Biruni University, Istanbul, Turkey
| | - Ozlem Saatci
- Department of Otorhinolaryngology, Istanbul Sancaktepe, Education and Research Hospital, Istanbul, Turkey
| | | | - Ozge Arici Duz
- Department of Neurology, Istanbul Medipol University, Istanbul, Turkey
| | - Ahmet Necati Sanli
- Department of General Surgery, Cerrahpasa Medical Faculty, Istanbul University-Cerrahpasa, Istanbul, Turkey.
| | - Oktay Olmuscelik
- Department of Internal Medicine, Istanbul Medipol University, Istanbul, Turkey
| | - Dastan Temirbekov
- Department of Otorhinolaryngology, Medicalpark Florya Hospital, Istanbul, Turkey
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6
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Lee JC, Nallani R, Cass L, Bhalla V, Chiu AG, Villwock JA. A Systematic Review of the Neuropathologic Findings of Post-Viral Olfactory Dysfunction: Implications and Novel Insight for the COVID-19 Pandemic. Am J Rhinol Allergy 2021; 35:323-333. [PMID: 32915650 PMCID: PMC10404900 DOI: 10.1177/1945892420957853] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Post-viral olfactory dysfunction is a common cause of both short- and long-term smell alteration. The coronavirus pandemic further highlights the importance of post-viral olfactory dysfunction. Currently, a comprehensive review of the neural mechanism underpinning post-viral olfactory dysfunction is lacking. OBJECTIVES To synthesize the existing primary literature related to olfactory dysfunction secondary to viral infection, detail the underlying pathophysiological mechanisms, highlight relevance for the current COVID-19 pandemic, and identify high impact areas of future research. METHODS PubMed and Embase were searched to identify studies reporting primary scientific data on post-viral olfactory dysfunction. Results were supplemented by manual searches. Studies were categorized into animal and human studies for final analysis and summary. RESULTS A total of 38 animal studies and 7 human studies met inclusion criteria and were analyzed. There was significant variability in study design, experimental model, and outcome measured. Viral effects on the olfactory system varies significantly based on viral substrain but generally include damage or alteration in components of the olfactory epithelium and/or the olfactory bulb. CONCLUSIONS The mechanism of post-viral olfactory dysfunction is highly complex, virus-dependent, and involves a combination of insults at multiple levels of the olfactory pathway. This will have important implications for future diagnostic and therapeutic developments for patients infected with COVID-19.
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Affiliation(s)
- Jason C. Lee
- Department of Otolaryngology—Head and Neck Surgery, University of Kansas School of Medicine, Kansas City, Kansas
| | - Rohit Nallani
- Department of Otolaryngology—Head and Neck Surgery, University of Kansas School of Medicine, Kansas City, Kansas
| | - Lauren Cass
- Department of Otolaryngology—Head and Neck Surgery, University of Kansas School of Medicine, Kansas City, Kansas
| | - Vidur Bhalla
- Saint Luke’s Hospital of Kansas City, Kansas City, Missouri
| | - Alexander G. Chiu
- Department of Otolaryngology—Head and Neck Surgery, University of Kansas School of Medicine, Kansas City, Kansas
| | - Jennifer A. Villwock
- Department of Otolaryngology—Head and Neck Surgery, University of Kansas School of Medicine, Kansas City, Kansas
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7
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Sbrana MF, Fornazieri MA, Bruni-Cardoso A, Avelino-Silva VI, Schechtman D, Voegels RL, Malnic B, Glezer I, de Rezende Pinna F. Olfactory Dysfunction in Frontline Health Care Professionals During COVID-19 Pandemic in Brazil. Front Physiol 2021; 12:622987. [PMID: 33767631 PMCID: PMC7985267 DOI: 10.3389/fphys.2021.622987] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 01/20/2021] [Indexed: 12/31/2022] Open
Abstract
Upper respiratory viral infections can decrease the sense of smell either by inflammatory restriction of nasal airflow that carries the odorant molecules or through interference in olfactory sensory neuron function. During the coronavirus disease 2019 (COVID-19) pandemic, triggered by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), worldwide reports of severe smell loss (anosmia/hyposmia) revealed a different type of olfactory dysfunction associated with respiratory virus infection. Since self-reported perception of smell is subjective and SARS-CoV-2 exposure is variable in the general population, we aimed to study a population that would be more homogeneously exposed to the virus. Here, we investigated the prevalence of olfactory loss in frontline health professionals diagnosed with COVID-19 in Brazil, one of the major epicenters of the disease. We also analyzed the rate of olfactory function recovery and the particular characteristics of olfactory deficit in this population. A widely disclosed cross-sectional online survey directed to health care workers was developed by a group of researchers to collect data concerning demographic information, general symptoms, otolaryngological symptoms, comorbidities, and COVID-19 test results. Of the 1,376 health professionals who completed the questionnaire, 795 (57.8%) were working directly with COVID-19 patients, either in intensive care units, emergency rooms, wards, outpatient clinics, or other areas. Five-hundred forty-one (39.3%) participants tested positive for SARS-CoV-2, and 509 (37%) were not tested. Prevalence of olfactory dysfunction in COVID-19-positive subjects was 83.9% (454 of 541) compared to 12.9% (42 of 326) of those who tested negative and to 14.9% (76 of 509) of those not tested. Olfactory dysfunction incidence was higher in those working in wards, emergency rooms, and intensive care units compared to professionals in outpatient clinics. In general, remission from olfactory symptoms was frequent by the time of responses. Taste disturbances were present in 74.1% of infected participants and were significantly associated with hyposmia. In conclusion, olfactory dysfunction is highly correlated with exposure to SARS-CoV-2 in health care professionals, and remission rates up to 2 weeks are high.
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Affiliation(s)
- Mariana Ferreira Sbrana
- Department of Otorhinolaryngology, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Marco Aurélio Fornazieri
- Department of Clinical Surgery, Universidade Estadual de Londrina and Pontifical Catholic University of Paraná, Londrina, Brazil
| | - Alexandre Bruni-Cardoso
- Department of Biochemistry, Institute of Chemistry, Universidade de São Paulo, São Paulo, Brazil
| | - Vivian I. Avelino-Silva
- Department of Infectious and Parasitic Diseases, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Deborah Schechtman
- Department of Biochemistry, Institute of Chemistry, Universidade de São Paulo, São Paulo, Brazil
| | - Richard Louis Voegels
- Department of Otorhinolaryngology, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Bettina Malnic
- Department of Biochemistry, Institute of Chemistry, Universidade de São Paulo, São Paulo, Brazil
| | - Isaias Glezer
- Department of Biochemistry, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Fabio de Rezende Pinna
- Department of Otorhinolaryngology, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
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8
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Porta-Etessam J, Núñez-Gil IJ, González García N, Fernandez-Perez C, Viana-Llamas MC, Eid CM, Romero R, Molina M, Uribarri A, Becerra-Muñoz VM, Aguado MG, Huang J, Rondano E, Cerrato E, Alfonso E, Mejía AFC, Marin F, Roubin SR, Pepe M, Feltes G, Maté P, Cortese B, Buzón L, Mendez JJ, Estrada V. COVID-19 anosmia and gustatory symptoms as a prognosis factor: a subanalysis of the HOPE COVID-19 (Health Outcome Predictive Evaluation for COVID-19) registry. Infection 2021; 49:677-684. [PMID: 33646505 PMCID: PMC7917537 DOI: 10.1007/s15010-021-01587-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 02/08/2021] [Indexed: 12/13/2022]
Abstract
Olfactory and gustatory dysfunctions (OGD) are a frequent symptom of coronavirus disease 2019 (COVID-19). It has been proposed that the neuroinvasive potential of the novel SARS-CoV-2 could be due to olfactory bulb invasion, conversely studies suggest it could be a good prognostic factor. The aim of the current study was to investigate the prognosis value of OGD in COVID-19. These symptoms were recorded on admission from a cohort study of 5868 patients with confirmed or highly suspected COVID-19 infection included in the multicenter international HOPE Registry (NCT04334291). There was statistical relation in multivariate analysis for OGD in gender, more frequent in female 12.41% vs 8.67% in male, related to age, more frequent under 65 years, presence of hypertension, dyslipidemia, diabetes, smoke, renal insufficiency, lung, heart, cancer and neurological disease. We did not find statistical differences in pregnant (p = 0.505), patient suffering cognitive (p = 0.484), liver (p = 0.1) or immune disease (p = 0.32). There was inverse relation (protective) between OGD and prone positioning (0.005) and death (< 0.0001), but no with ICU (0.165) or mechanical ventilation (0.292). On univariable logistic regression, OGD was found to be inversely related to death in COVID-19 patients. The odds ratio was 0.26 (0.15-0.44) (p < 0.001) and Z was - 5.05. The presence of anosmia is fundamental in the diagnosis of SARS.CoV-2 infection, but also could be important in classifying patients and in therapeutic decisions. Even more knowing that it is an early symptom of the disease. Knowing that other situations as being Afro-American or Latino-American, hypertension, renal insufficiency, or increase of C-reactive protein (CRP) imply a worse prognosis we can make a clinical score to estimate the vital prognosis of the patient. The exact pathogenesis of SARS-CoV-2 that causes olfactory and gustative disorders remains unknown but seems related to the prognosis. This point is fundamental, insomuch as could be a plausible way to find a treatment.
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Affiliation(s)
- Jesús Porta-Etessam
- Hospital Clínico San Carlos, Madrid, Spain. .,Universidad Complutense de Madrid, Madrid, Spain. .,Neurology Department. C/Profesor Martín Lagos S/N, 28049, Madrid, Spain.
| | | | - Nuria González García
- Hospital Clínico San Carlos, Madrid, Spain.,Neurology Department. C/Profesor Martín Lagos S/N, 28049, Madrid, Spain
| | | | | | - Charbel Maroun Eid
- Hospital Universitario La Paz. Instituto de Investigación Hospital Universitario La Paz (IdiPAZ), Madrid, Spain
| | | | - María Molina
- Hospital Universitario Severo Ochoa, Leganés, Spain
| | - Aitor Uribarri
- Hospital Clínico Universitario de Valladolid, Valladolid, Spain
| | | | | | - Jia Huang
- The Second Affiliated Hospital of Southern, University of Science and Technology Shenzhen, Shenzhen, China
| | | | - Enrico Cerrato
- San Luigi Gonzaga University Hospital, Orbassano and Rivoli Infermi Hospital, Rivoli, Turin, Italy
| | - Emilio Alfonso
- Institute of Cardiology and Cardiovascular Surgery, Havana, Cuba
| | | | | | | | - Martino Pepe
- Azienda Ospedaliero-Universitaria Consorziale Policlinico Di Bari, Bari, Italy
| | | | - Paloma Maté
- Hospital Universitario Infanta Sofia, San Sebastian de Los Reyes, Madrid, Spain
| | | | - Luis Buzón
- Hospital Universitario de Burgos, Burgos, Spain
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9
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Abstract
Due to the rapid spread of the SARS-CoV-2 virus, many health systems worldwide are overwhelmed, leading to the triggering of the scarcity of medical resources. The identification of indicators that require hospital admission help in the efficient allocation of medical resources. Olfactory impairment is also one of the indicators of COVID-19 infection. Many studies have analyzed olfactory dysfunction in COVID-19 with a variable prevalence rate but underreporting of this problem is very much likely as the problem is considered benign. Many scientific societies have stated that olfactory dysfunction is a frequent symptom of COVID-19 and have published recommendations for it.
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10
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Yazdanpanah N, Saghazadeh A, Rezaei N. Anosmia: a missing link in the neuroimmunology of coronavirus disease 2019 (COVID-19). Rev Neurosci 2020; 31:691-701. [PMID: 32776905 DOI: 10.1515/revneuro-2020-0039] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 07/19/2020] [Indexed: 12/22/2022]
Abstract
Just before 2020 began, a novel coronavirus, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), brought for humans a potentially fatal disease known as coronavirus disease 2019 (COVID-19). The world has thoroughly been affected by COVID-19, while there has been little progress towards understanding the pathogenesis of COVID-19. Patients with a severe phenotype of disease and those who died from the disease have shown hyperinflammation and were more likely to develop neurological manifestations, linking the clinical disease with neuroimmunological features. Anosmia frequently occurs early in the course of COVID-19. The prevalence of anosmia would be influenced by self-diagnosis as well as self-misdiagnosis in patients with COVID-19. Despite this, the association between anosmia and COVID-19 has been a hope for research, aiming to understand the pathogenesis of COVID-19. Studies have suggested differently probable mechanisms for the development of anosmia in COVID-19, including olfactory cleft syndrome, postviral anosmia syndrome, cytokine storm, direct damage of olfactory sensory neurons, and impairment of the olfactory perception center in the brain. Thus, the observation of anosmia would direct us to find the pathogenesis of COVID-19 in the central nervous system, and this is consistent with numerous neurological manifestations related to COVID-19. Like other neurotropic viruses, SARS-CoV-2 might be able to enter the central nervous system via the olfactory epithelium and induce innate immune responses at the site of entry. Viral replication in the nonneural olfactory cells indirectly causes damage to the olfactory receptor nerves, and as a consequence, anosmia occurs. Further studies are required to investigate the neuroimmunology of COVID-19 in relation to anosmia.
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Affiliation(s)
- Niloufar Yazdanpanah
- Systematic Review and Meta-analysis Expert Group (SRMEG), Universal Scientific Education and Research Network (USERN), Tehran, 14194, Iran
- Research Center for Immunodeficiencies, Tehran University of Medical Sciences, Children's Medical Center, Dr. Qarib St, Keshavarz Blvd, Tehran, 14194, Iran
| | - Amene Saghazadeh
- Research Center for Immunodeficiencies, Tehran University of Medical Sciences, Children's Medical Center, Dr. Qarib St, Keshavarz Blvd, Tehran, 14194, Iran
- NeuroImmunology Research Association (NIRA), Universal Scientific Education and Research Network (USERN), Tehran, 14194, Iran
| | - Nima Rezaei
- Research Center for Immunodeficiencies, Tehran University of Medical Sciences, Children's Medical Center, Dr. Qarib St, Keshavarz Blvd, Tehran, 14194, Iran
- Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, 14194, Iran
- Network of Immunity in Infection, Malignancy and Autoimmunity (NIIMA), Universal Scientific Education and Research Network (USERN), Tehran, 14194, Iran
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11
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Baig AM, Sanders EC. Potential neuroinvasive pathways of SARS-CoV-2: Deciphering the spectrum of neurological deficit seen in coronavirus disease-2019 (COVID-19). J Med Virol 2020; 92:1845-1857. [PMID: 32492193 PMCID: PMC7300748 DOI: 10.1002/jmv.26105] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 05/26/2020] [Indexed: 12/15/2022]
Abstract
Coronavirus disease-2019 (COVID-19) was declared a global pandemic on 11 March 2020. Scientists and clinicians must acknowledge that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has the potential to attack the human body in multiple ways simultaneously and exploit any weaknesses of its host. A multipronged attack could potentially explain the severity and extensive variety of signs and symptoms observed in patients with COVID-19. Understanding the diverse tactics of this virus to infect the human body is both critical and incredibly complex. Although patients diagnosed with COVID-19 have primarily presented with pulmonary involvement, viral invasion, and injury to diverse end organs is also prevalent and well documented in these patients, but has been largely unheeded. Human organs known for angiotensin-converting enzyme 2 (ACE2) expression including the gastrointestinal tract, kidneys, heart, adrenals, brain, and testicles are examples of extra pulmonary tissues with confirmed invasion by SARS-CoV-2. Initial multiple organ involvement may present with vague signs and symptoms to alert health care professionals early in the course of COVID-19. Another example of an ongoing, yet neglected element of the syndromic features of COVID-19, are the reported findings of loss of smell, altered taste, ataxia, headache, dizziness, and loss of consciousness, which suggest a potential for neural involvement. In this review, we further deliberate on the neuroinvasive potential of SARS-CoV-2, the neurologic symptomology observed in COVID-19, the host-virus interaction, possible routes of SARS-CoV-2 to invade the central nervous system, other neurologic considerations for patients with COVID-19, and a collective call to action.
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Affiliation(s)
- Abdul Mannan Baig
- Department of Biological and Biomedical SciencesAga Khan UniversityKarachiSindhPakistan
| | - Erin C. Sanders
- Department of Obstetrics and GynecologyMount Auburn Hospital, Boston Urogynecology AssociatesCambridgeMassachusettsUnited States
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Brann DH, Tsukahara T, Weinreb C, Lipovsek M, Van den Berge K, Gong B, Chance R, Macaulay IC, Chou HJ, Fletcher RB, Das D, Street K, de Bezieux HR, Choi YG, Risso D, Dudoit S, Purdom E, Mill J, Hachem RA, Matsunami H, Logan DW, Goldstein BJ, Grubb MS, Ngai J, Datta SR. Non-neuronal expression of SARS-CoV-2 entry genes in the olfactory system suggests mechanisms underlying COVID-19-associated anosmia. SCIENCE ADVANCES 2020; 6:eabc5801. [PMID: 32937591 PMCID: PMC10715684 DOI: 10.1126/sciadv.abc5801] [Citation(s) in RCA: 685] [Impact Index Per Article: 171.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 06/18/2020] [Indexed: 05/05/2023]
Abstract
Altered olfactory function is a common symptom of COVID-19, but its etiology is unknown. A key question is whether SARS-CoV-2 (CoV-2) - the causal agent in COVID-19 - affects olfaction directly, by infecting olfactory sensory neurons or their targets in the olfactory bulb, or indirectly, through perturbation of supporting cells. Here we identify cell types in the olfactory epithelium and olfactory bulb that express SARS-CoV-2 cell entry molecules. Bulk sequencing demonstrated that mouse, non-human primate and human olfactory mucosa expresses two key genes involved in CoV-2 entry, ACE2 and TMPRSS2. However, single cell sequencing revealed that ACE2 is expressed in support cells, stem cells, and perivascular cells, rather than in neurons. Immunostaining confirmed these results and revealed pervasive expression of ACE2 protein in dorsally-located olfactory epithelial sustentacular cells and olfactory bulb pericytes in the mouse. These findings suggest that CoV-2 infection of non-neuronal cell types leads to anosmia and related disturbances in odor perception in COVID-19 patients.
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Affiliation(s)
- David H Brann
- Harvard Medical School Department of Neurobiology, Boston MA 02115 USA
| | - Tatsuya Tsukahara
- Harvard Medical School Department of Neurobiology, Boston MA 02115 USA
| | - Caleb Weinreb
- Harvard Medical School Department of Neurobiology, Boston MA 02115 USA
| | - Marcela Lipovsek
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London, London SE1 1UL, UK
| | - Koen Van den Berge
- Department of Statistics, University of California, Berkeley, CA 94720
- Department of Applied Mathematics, Computer Science and Statistics, Ghent University, Ghent, Belgium
| | - Boying Gong
- Division of Biostatistics, School of Public Health, University of California, Berkeley, CA 94720
| | - Rebecca Chance
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
| | - Iain C Macaulay
- Earlham Institute, Norwich Research Park, Norwich, NR4 7UZ, UK
| | - Hsin-Jung Chou
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
| | - Russell B Fletcher
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
- Present address: Surrozen, Inc., South San Francisco, CA 94080
| | - Diya Das
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
- Berkeley Institute for Data Science, University of California, Berkeley
- Present address: Genentech, Inc., South San Francisco, CA 94080
| | - Kelly Street
- Department of Data Sciences, Dana-Farber Cancer Institute, Boston, MA
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA
| | - Hector Roux de Bezieux
- Division of Biostatistics, School of Public Health, University of California, Berkeley, CA 94720
- Center for Computational Biology, University of California, Berkeley, CA 94720
| | - Yoon-Gi Choi
- QB3 Functional Genomics Laboratory, University of California, Berkeley, CA 94720
| | - Davide Risso
- Department of Statistical Sciences, University of Padova, Padova, Italy
| | - Sandrine Dudoit
- Department of Statistics, University of California, Berkeley, CA 94720
- Division of Biostatistics, School of Public Health, University of California, Berkeley, CA 94720
| | - Elizabeth Purdom
- Department of Statistics, University of California, Berkeley, CA 94720
| | - Jonathan Mill
- University of Exeter Medical School, College of Medicine & Health, University of Exeter, Exeter EX2 5DW, UK
| | - Ralph Abi Hachem
- Duke University School of Medicine Department of Head and Neck Surgery & Communication Sciences, Durham, NC 27717 USA
| | - Hiroaki Matsunami
- Duke University School of Medicine Department of Molecular Genetics and Microbiology, Department of Neurobiology, Duke Institute for Brain Sciences, Durham, NC 27717 US
| | - Darren W Logan
- Waltham Petcare Science Institute, Leicestershire LE14 4RT, UK
| | - Bradley J Goldstein
- Duke University School of Medicine Department of Head and Neck Surgery & Communication Sciences, Durham, NC 27717 USA
| | - Matthew S Grubb
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London, London SE1 1UL, UK
| | - John Ngai
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
- QB3 Functional Genomics Laboratory, University of California, Berkeley, CA 94720
- Helen Wills Neuroscience Institute, University of California, Berkeley, CA 94720
- Present address: National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
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Salmon Ceron D, Bartier S, Hautefort C, Nguyen Y, Nevoux J, Hamel AL, Camhi Y, Canouï-Poitrine F, Verillaud B, Slama D, Haim-Boukobza S, Sourdeau E, Cantin D, Corré A, Bryn A, Etienne N, Rozenberg F, Layese R, Papon JF, Bequignon E. Self-reported loss of smell without nasal obstruction to identify COVID-19. The multicenter Coranosmia cohort study. J Infect 2020; 81:614-620. [PMID: 32650110 PMCID: PMC7338860 DOI: 10.1016/j.jinf.2020.07.005] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 07/02/2020] [Accepted: 07/03/2020] [Indexed: 12/23/2022]
Abstract
Isolated loss of smell without nasal obstruction is an early red-flag of COVID-19. These patients should adopt all the preventive measures and a lockdown. Olfactory/gustative dysfunction had high predictive value to identify COVID-19. Olfactory/gustative dysfunction had high specificity to identify COVID-19. Self-reported loss of smell, among other symptoms, could help to screen COVID-19.
Objectives To determine the frequency of SARS-CoV-2 positive samples in a subset of patients consulting for primarily isolated acute (<7 days) loss of smell and to assess the diagnostic accuracy of olfactory/gustatory dysfunction for COVID-19 diagnosis in the overall population tested for COVID-19 in the same period. Methods Prospective multicentric cohort study in four olfactory ENT units and a screening center for COVID-19. Results i) Among a subset of 55 patients consulting for primarily recent loss of smell, we found that 51 (92.7%) had a COVID-19 positive test (median viral load of 28.8 cycle threshold). Loss of smell was mostly total (anosmia), rarely associated with nasal obstruction but associated with a taste disorder in 80%. Olfactory dysfunction occurred suddenly, either as first complaint or preceded by mild symptoms occurring a median of 3 days. The majority of patients (72.9%) partially recovered the sense of smell within 15 days. ii) In a population of 1824 patients tested for COVID-19, the positive predictive value and the specificity of loss of smell and/or taste were 78.5% and 90.3% respectively (sensitivity (40.8%), negative predictive value (63.6%)). Conclusions Self-reported loss of smell had a high predictive positive value to identify COVID-19. Making this sign well known publicly could help to adopt isolation measures and inform potential contacts.
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Affiliation(s)
- Dominique Salmon Ceron
- Department of Infectious Diseases and Immunology, Hotel Dieu Hospital, Paris Public Hospitals (APHP), 1 Place du Parvis de Notre-Dame, Paris 75004, France; University of Paris, School of Medicine, Paris 75005, France.
| | - Sophie Bartier
- Department of Oto-rhino-laryngology, Head and Neck Surgery, Intercommunal Hospital of Créteil, Créteil 94000, France; University Paris-Est Créteil (UPEC), School of Medicine, Créteil 94000, France; INSERM U955, IMRB- CEpiA team, 94000 Créteil, France Paris Public Hospitals Henri Mondor Hospital (APHP), Créteil 94000, France; Department of Oto-rhino-laryngology, Henri Mondor Hospital of Créteil, Paris Public Hospitals, Créteil 94000, France; Centre National de la Recherche Scientifique CNRS, ERL 7000, Créteil 94000, France
| | - Charlotte Hautefort
- Department of Oto-rhino-laryngology Head and Neck Surgery, Paris Public Hospitals, Lariboisière Hospital (APHP), Paris 75010, France; University Paris Diderot, School of Medicine, Paris 75010, France
| | - Yann Nguyen
- Department of Oto-rhino-laryngology Head and Neck Surgery, Paris Public Hospitals, AP-HP Sorbonne University Hospital Pitié Salpêtrière Hospital (AP-HP), Paris 75006, France; Sorbonne University, Paris 75013, France
| | - Jérôme Nevoux
- Groupe Hospitalier Paris-Saclay, Hôpital Bicêtre, Department of Oto-rhino-laryngology Head and Neck Surgery, Paris Public Hospitals. Le Kremlin-Bicêtre 94270, France; Université Paris-Saclay, Faculté de Médecine, Le Kremlin-Bicêtre F-94275, France
| | - Anne-Laure Hamel
- Department of Oto-rhino-laryngology Head and Neck Surgery, Paris Public Hospitals, Lariboisière Hospital (APHP), Paris 75010, France; University Paris Diderot, School of Medicine, Paris 75010, France
| | - Yohan Camhi
- Department of Oto-rhino-laryngology Head and Neck Surgery, Paris Public Hospitals, AP-HP Sorbonne University Hospital Pitié Salpêtrière Hospital (AP-HP), Paris 75006, France
| | - Florence Canouï-Poitrine
- University Paris-Est Créteil (UPEC), School of Medicine, Créteil 94000, France; INSERM U955, IMRB- CEpiA team, 94000 Créteil, France Paris Public Hospitals Henri Mondor Hospital (APHP), Créteil 94000, France; Clinical Research Unit: (URC-Mondor), Department of Public Health, Henri Mondor Hospital Paris Public Hospitals (AP-HP), Créteil 94000, France
| | - Benjamin Verillaud
- Department of Oto-rhino-laryngology Head and Neck Surgery, Paris Public Hospitals, Lariboisière Hospital (APHP), Paris 75010, France; University Paris Diderot, School of Medicine, Paris 75010, France
| | - Dorsaf Slama
- Department of Infectious Diseases and Immunology, Hotel Dieu Hospital, Paris Public Hospitals (APHP), 1 Place du Parvis de Notre-Dame, Paris 75004, France
| | | | - Elise Sourdeau
- Emergency Department, Hotel Dieu Hospital, Paris Public Hospitals (APHP), Paris 75004, France
| | - Delphine Cantin
- Emergency Department, Hotel Dieu Hospital, Paris Public Hospitals (APHP), Paris 75004, France
| | - Alain Corré
- Department of Oto-rhino-laryngology Head and Neck Surgery, Hopital Rothschild Foundation, Paris, France
| | - Agnes Bryn
- University of Paris, School of Medicine, Paris 75005, France; General Medical Practioner, Paris, France
| | - Nicolas Etienne
- Department of Infectious Diseases and Immunology, Hotel Dieu Hospital, Paris Public Hospitals (APHP), 1 Place du Parvis de Notre-Dame, Paris 75004, France
| | - Flore Rozenberg
- University of Paris, School of Medicine, Paris 75005, France; Virology Department, Cochin Hospital, Paris Public Hospitals (APHP), Paris 75004, France
| | - Richard Layese
- University Paris-Est Créteil (UPEC), School of Medicine, Créteil 94000, France; INSERM U955, IMRB- CEpiA team, 94000 Créteil, France Paris Public Hospitals Henri Mondor Hospital (APHP), Créteil 94000, France; Clinical Research Unit: (URC-Mondor), Department of Public Health, Henri Mondor Hospital Paris Public Hospitals (AP-HP), Créteil 94000, France
| | - Jean-François Papon
- INSERM U955, IMRB- CEpiA team, 94000 Créteil, France Paris Public Hospitals Henri Mondor Hospital (APHP), Créteil 94000, France; Centre National de la Recherche Scientifique CNRS, ERL 7000, Créteil 94000, France; Groupe Hospitalier Paris-Saclay, Hôpital Bicêtre, Department of Oto-rhino-laryngology Head and Neck Surgery, Paris Public Hospitals. Le Kremlin-Bicêtre 94270, France; Université Paris-Saclay, Faculté de Médecine, Le Kremlin-Bicêtre F-94275, France
| | - Emilie Bequignon
- Department of Oto-rhino-laryngology, Head and Neck Surgery, Intercommunal Hospital of Créteil, Créteil 94000, France; University Paris-Est Créteil (UPEC), School of Medicine, Créteil 94000, France; INSERM U955, IMRB- CEpiA team, 94000 Créteil, France Paris Public Hospitals Henri Mondor Hospital (APHP), Créteil 94000, France; Department of Oto-rhino-laryngology, Henri Mondor Hospital of Créteil, Paris Public Hospitals, Créteil 94000, France; Centre National de la Recherche Scientifique CNRS, ERL 7000, Créteil 94000, France
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Vaira LA, Salzano G, Fois AG, Piombino P, De Riu G. Potential pathogenesis of ageusia and anosmia in COVID-19 patients. Int Forum Allergy Rhinol 2020; 10:1103-1104. [PMID: 32342636 PMCID: PMC7267531 DOI: 10.1002/alr.22593] [Citation(s) in RCA: 165] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 04/21/2020] [Accepted: 04/21/2020] [Indexed: 11/09/2022]
Affiliation(s)
- Luigi Angelo Vaira
- Maxillofacial Surgery Unit, University Hospital of Sassari, Sassari, Italy
| | - Giovanni Salzano
- Maxillofacial Surgery Unit, University Hospital of Naples "Federico II", Naples, Italy
| | | | - Pasquale Piombino
- Maxillofacial Surgery Unit, University Hospital of Naples "Federico II", Naples, Italy
| | - Giacomo De Riu
- Maxillofacial Surgery Unit, University Hospital of Sassari, Sassari, Italy
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Coalition: Advocacy for prospective clinical trials to test the post-exposure potential of hydroxychloroquine against COVID-19. One Health 2020; 9:100131. [PMID: 32292817 PMCID: PMC7128742 DOI: 10.1016/j.onehlt.2020.100131] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Our coalition of public health experts, doctors, and scientists worldwide want to draw attention to the need for high-quality evaluation protocols of the potential beneficial effect of hydroxychloroquine (HCQ) as a post-exposure drug for exposed people. In the absence of an approved, recognized effective pre or post-exposure prophylactic drug or vaccine for COVID-19, nor of any approved and validated therapeutic drug, coupled with social and political pressure raised by publicity both regarding the potential beneficial effect of hydroxychloroquine (HCQ) as well as potential risks from HCQ, we urge the immediate proper clinical trials. Specifically, we mean using HCQ for post-exposure of people with close contact with patients with positive COVID19 rtPCR, including home and medical caregivers. We have reviewed the mechanisms of antiviral effect of HCQ, the risk-benefit ratio taking into consideration the PK/PD of HCQ and the thresholds of efficacy. We have studied its use as an antimalarial, an antiviral, and an immunomodulating drug and concluded that the use of HCQ at doses matching that of the standard treatment of Systemic Lupus erythematous, which has proven safety and efficacy in terms of HCQ blood and tissue concentration adapted to bodyweight (2,3), at 6 mg/kg/day 1 (loading dose) followed by 5 mg/kg/ day, with a maximum limit of 600 mg/day in all cases should swiftly be clinically evaluated as a post-exposure drug for exposed people.
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Wheeler DL, Sariol A, Meyerholz DK, Perlman S. Microglia are required for protection against lethal coronavirus encephalitis in mice. J Clin Invest 2018; 128:931-943. [PMID: 29376888 DOI: 10.1172/jci97229] [Citation(s) in RCA: 123] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 12/12/2017] [Indexed: 11/17/2022] Open
Abstract
Recent findings have highlighted the role of microglia in orchestrating normal development and refining neural network connectivity in the healthy CNS. Microglia are not only vital cells in maintaining CNS homeostasis, but also respond to injury, infection, and disease by undergoing proliferation and changes in transcription and morphology. A better understanding of the specific role of microglia in responding to viral infection is complicated by the presence of nonmicroglial myeloid cells with potentially overlapping function in the healthy brain and by the rapid infiltration of hematopoietic myeloid cells into the brain in diseased states. Here, we used an inhibitor of colony-stimulating factor 1 receptor (CSF1R) that depletes microglia to examine the specific roles of microglia in response to infection with the mouse hepatitis virus (MHV), a neurotropic coronavirus. Our results show that microglia were required during the early days after infection to limit MHV replication and subsequent morbidity and lethality. Additionally, microglia depletion resulted in ineffective T cell responses. These results reveal nonredundant, critical roles for microglia in the early innate and virus-specific T cell responses and for subsequent host protection from viral encephalitis.
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Affiliation(s)
| | - Alan Sariol
- Interdisciplinary Graduate Program in Immunology
| | | | - Stanley Perlman
- Interdisciplinary Graduate Program in Immunology.,Department of Microbiology and Immunology, University of Iowa, Iowa City, Iowa, USA
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Murine Olfactory Bulb Interneurons Survive Infection with a Neurotropic Coronavirus. J Virol 2017; 91:JVI.01099-17. [PMID: 28835503 DOI: 10.1128/jvi.01099-17] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 08/18/2017] [Indexed: 12/22/2022] Open
Abstract
Viral infection of the central nervous system (CNS) is complicated by the mostly irreplaceable nature of neurons, as the loss of neurons has the potential to result in permanent damage to brain function. However, whether neurons or other cells in the CNS sometimes survive infection and the effects of infection on neuronal function is largely unknown. To address this question, we used the rJHM strain (rJ) of mouse hepatitis virus (MHV), a neurotropic coronavirus that causes acute encephalitis in susceptible strains of mice. To determine whether neurons or other CNS cells survive acute infection with this virulent virus, we developed a recombinant JHMV that expresses Cre recombinase (rJ-Cre) and infected mice that universally expressed a silent (floxed) version of tdTomato. Infection of these mice with rJ-Cre resulted in expression of tdTomato in host cells. The results showed that some cells were able to survive the infection, as demonstrated by continued tdTomato expression after virus antigen could no longer be detected. Most notably, interneurons in the olfactory bulb, which are known to be inhibitory, represented a large fraction of the surviving cells. In conclusion, our results indicated that some neurons are resistant to virus-mediated cell death and provide a framework for studying the effects of prior coronavirus infection on neuron function.IMPORTANCE We developed a novel recombinant virus that allows the study of cells that survive an infection by a central nervous system-specific strain of murine coronavirus. Using this virus, we identified neurons and, to a lesser extent, nonneuronal cells in the brain that were infected during the acute phase of the infection and survived for approximately 2 weeks until the mice succumbed to the infection. We focused on neurons and glial cells within the olfactory bulb because the virus enters the brain at this site. Our results show that interneurons of the olfactory bulb were the primary cell type able to survive infection. Further, these results indicate that this system will be useful for functional and gene expression studies of cells in the brain that survive acute infection.
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Thakur A, Muniswami D, Tharion G, Kanakasabapathy I. Immunohistological and electrophysiological characterization of Globose basal stem cells. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2014; 17:278-86. [PMID: 24904721 PMCID: PMC4046242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 01/07/2014] [Indexed: 12/03/2022]
Abstract
OBJECTIVES In the past few decades, variety of foetal, embryonic and adult stem and progenitor cells have been tried with conflicting outcome for cell therapy of central nervous system injury and diseases. Cellular characteristics and functional plasticity of Globose basal stem cells (GBCs) residing in the olfactory epithelium of rat olfactory mucosa have not been studied in the past by the neuroscientists due to unavailability of specific markers for GBCs. In the present research, we standardized some techniques to isolate GBCs from rat olfactory epithelium in pure form using a highly selective GBC-III antibody passaged through fluorescence activated cell sorter (FACS). We also characterized these cells immunohistologically using various pluripotent stem cell markers. This work also throws some light on ionic channels present on these stem cells which are responsible for their neuron induction potential. MATERIALS AND METHODS Globose basal stem cells were isolated from rat olfactory epithelium using GBC-III antibody and were characterized as multipotent stem cells using various neural progenitor markers. Ionic channels on GBCs were studied with voltage clamping. RESULTS GBCs could be isolated in pure (99% purity) form and were found to be stained positive for all neural progenitor cell markers. Voltage gated Na(+) channels were completely absent, which proves the unexcitable nature of GBCs. Leaky K(+) channels were found to be present on the GBC which was of no significance. CONCLUSION This research work can be helpful in understanding the nature of these stem cells and utilising them in future as potent candidates for neuro-regenerative therapies.
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Affiliation(s)
- Avinash Thakur
- Department of Anatomy, Vardhman Mahavir Medical College & Safdarjung Hospital, New Delhi- 110029, India,Corresponding author: Avinash Thakur. Department of Anatomy, Vardhman Mahavir Medical College & Safdarjung hospital, New Delhi- 110029, India. Tel: 091-9310203126;
| | - Duraimurugan Muniswami
- Department of Physical Medicine and Rehabilitation, Christian Medical College Vellore, India
| | - George Tharion
- Department of Physical Medicine and Rehabilitation, Christian Medical College, Vellore, India
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Loseva E, Yuan TF, Karnup S. Neurogliogenesis in the mature olfactory system: a possible protective role against infection and toxic dust. ACTA ACUST UNITED AC 2008; 59:374-87. [PMID: 19027790 PMCID: PMC7112504 DOI: 10.1016/j.brainresrev.2008.10.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2008] [Revised: 10/01/2008] [Accepted: 10/25/2008] [Indexed: 01/12/2023]
Abstract
The outpost position of the olfactory bulb (OB) between the direct inputs from sensory neurons of the nasal epithelium and other parts of the brain suggests its highest vulnerability among all brain structures to penetration of exogenous agents. A number of neurotropic viruses have been found to invade the brain through the OB. There is growing evidence that microscopic particles of toxic dusts can propagate from the nasal epithelium to the OB and further into the brain. These harmful agents impair cellular elements of the brain. Apparently, cells in the OB are the most affected, as they are the first to encounter viral infections and toxic particles. It is well known that neuronal and glial progenitors are continuously generated from neuronal stem cells in the subventricular zone of the adult brain and then migrate predominantly into the OB. Therefore, it is feasible to suggest that substitution of injured or dead cells in the OB by new-born neurons, differentiating from progenitors, plays a role in protecting the OB neuronal microcircuits from destruction. Furthermore, some cytokines and chemokines released in response to infection and/or intoxication can modulate different stages of neurogenesis (proliferation, migration, and differentiation). We hypothesize that continuous neurogenesis in the olfactory system throughout adulthood evolved as a protective mechanism to prevent impairment of the most ancient but vitally important sensory system. In addition, differentiation of a substantial portion of progenitors to glial cells, including macrophages and microglia, may create an additional barrier to exogenous agents on their way deep to the brain.
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Affiliation(s)
- Elena Loseva
- Institute of Higher Nervous Activity and Neurophysiology RAS, Moscow, Russia.
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20
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Venkatraman G, Behrens M, Pyrski M, Margolis FL. Expression of Coxsackie-Adenovirus receptor (CAR) in the developing mouse olfactory system. ACTA ACUST UNITED AC 2006; 34:295-305. [PMID: 16841169 DOI: 10.1007/s11068-005-8359-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2005] [Revised: 11/14/2005] [Accepted: 11/14/2005] [Indexed: 10/24/2022]
Abstract
Interest in manipulating gene expression in olfactory sensory neurons (OSNs) has led to the use of adenoviruses (AdV) as gene delivery vectors. OSNs are the first order neurons in the olfactory system and the initial site of odor detection. They are highly susceptible to adenovirus infection although the mechanism is poorly understood. The Coxsackie-Adenovirus receptor (CAR) and members of the integrin family have been implicated in the process of AdV infection in various systems. Multiple serotypes of AdV efficiently bind to the CAR, leading to entry and infection of the host cell by a mechanism that can also involve integrins. Cell lines that do not express CAR are relatively resistant, but not completely immune to AdV infection, suggesting that other mechanisms participate in mediating AdV attachment and entry. Using in situ hybridization and western blot analyses, we show that OSNs and olfactory bulbs (OB) of mice express abundant CAR mRNA at embryonic and neonatal stages, with progressive diminution during postnatal development. By contrast to the olfactory epithelium (OE), CAR mRNA is still present in the adult mouse OB. Furthermore, despite a similar postnatal decline, CAR protein expression in the OE and OB of mice continues into adulthood. Our results suggest that the robust AdV infection observed in the postnatal olfactory system is mediated by CAR and that expression of even small amounts of CAR protein as seen in the adult rodent, permits efficient AdV infection and entry. CAR is an immunoglobulin domain-containing protein that bears homology to cell-adhesion molecules suggesting the possibility that it may participate in organization of the developing olfactory system.
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Affiliation(s)
- Giri Venkatraman
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, 21201, USA
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Abstract
Olfactory loss can occur through accidental exposure, poor industrial hygiene, or exposure to low levels of toxins in the ambient air over long periods. This loss can lead to transient olfactory disorders, irreversible anosmia, temporary olfactory fatigue, or industrial anosmia. Inevitably, a practicing otolaryngologist will encounter a patient with complaints of decreased smell and taste that initially may be difficult to diagnose and treat. Much of the challenge in evaluating a patient with disturbances of olfaction is in obtaining adequate quantitative measurements of sensory dysfunction and identifying a source for the olfactory loss. Although there is no particular test for environmental toxins as a source of olfactory loss, an accurate cause can be determined by obtaining a careful, detailed history. A significant exposure history and lack of more common causes of olfactory loss strengthens an argument for environmental toxins as an etiology. Unfortunately, no available treatments can reverse permanent damage caused by toxic exposure, but removal from the source of toxins may allow for repair of the olfactory system and return of normal function, especially in acute exposures. Despite the increasing number of studies investigating toxic exposure on olfactory function, these effects are understood poorly. With continued study of human exposure to these substances and the use of animal models, the mechanisms by which damage occurs will be understood better and new approaches for diagnosis and treatment will be developed. Furthermore, with increasing regulations of occupational environments and stricter policies on industrial air pollution, olfactory dysfunction secondary to toxicity should become less prevalent.
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Affiliation(s)
- Urmen D Upadhyay
- Tufts University School of Medicine, New England Medical Center, 750 Washington Street, NEMC 850, Boston, MA 02111, USA
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22
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Abstract
We have developed a strategy for the rapid high-throughput screening of odor responsivity in genetically altered mice (in fact, any experimentally altered animal). Specifically, the report presents the development and validation of a fully automated procedure based on the evaluation of an animal's stimulus-induced reflexive breathing response (i.e. sniffing behavior) to both air and odorant stimuli. The method requires no training of the animal to be screened and the outcome of the evaluation yields an operationally defined measure. Briefly, using whole-body plethysmography, the procedure determines the numerical values for a set of 14 respiratory measures in response to the presentation of air and a well-above-threshold concentration of the odorant propanol. These measures of stimulus-induced sniffing are incorporated into a model that defines a single univariate measure of response behavior, or 'Sniffing Index', for each screened animal. The approach significantly discriminated between the reflexive sniffing response of a control group of mice and that of an experimentally defined manipulated group for which, a priori, we expected to observe a robust altered breathing response to odorant stimulation (i.e. non-odor-aversion-conditioned versus odor-aversion-conditioned C57BL/6J mice). Further, the procedure was able to significantly discriminate between a mutant phenotype with documented alterations in physiologic and behavioral function (namely, the OMP-null mutant), and their background strain. In addition, applying epidemiologic screening principles to the observed data, we established an operational procedure for the evaluation of unknown animals.
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Affiliation(s)
- Steven L Youngentob
- Department of Neuroscience and Physiology, SUNY Upstate Medical University, Institute for Human Performance, 750 East Adams Street, Syracuse, NY 13210. USA.
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Abstract
Disorders of the sense of smell can be frustrating for both the patient and physician. Ongoing research in this field has provided insight into the possible mechanisms for smell loss; however, therapy is still limited. Commercially distributed smell testing kits and newer screening tests using material available in all clinical settings have made diagnosis and measurement of the degree of impairment available to all physicians. A detailed history and physical examination are the most powerful tools in the evaluation of smell disorders, whereas imaging studies are reserved for preoperative planning or detailed assessment of positive physical findings.
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Affiliation(s)
- Eric H Holbrook
- Department of Otolaryngology-Head and Neck Surgery, University of Nebraska Medical Center, Omaha, Nebraska 68198-1225, USA
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Schwob JE, Saha S, Youngentob SL, Jubelt B. Intranasal inoculation with the olfactory bulb line variant of mouse hepatitis virus causes extensive destruction of the olfactory bulb and accelerated turnover of neurons in the olfactory epithelium of mice. Chem Senses 2001; 26:937-52. [PMID: 11595671 PMCID: PMC7110028 DOI: 10.1093/chemse/26.8.937] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Viral upper respiratory infections are the most common cause of clinical olfactory dysfunction, but the pathogenesis of dysosmia after viral infection is poorly understood. Biopsies of the olfactory mucosa in patients that complain of dysosmia after viral infection fall into two categories: one in which no olfactory epithelium is seen and another in which the epithelium is disordered and populated mainly by immature neurons. We have used intranasal inoculation with an olfactory bulb line variant of MHV to study the consequences of viral infection on peripheral olfactory structures. MHV OBLV has little direct effect on the olfactory epithelium, but causes extensive spongiotic degeneration and destruction of mitral cells and interneurons in the olfactory bulb such that the axonal projection from the bulb via the lateral olfactory tract is markedly reduced. Moreover, surviving mitral cells apparently remain disconnected from the sensory neuron input to the glomerular layer, judging from retrograde labeling studies using Dil. The damage to the bulb indirectly causes a persistent, long-term increase in the turnover of sensory neurons in the epithelium, i.e. the relative proportion of immature to mature sensory neurons and the rate of basal cell proliferation both increase. The changes that develop after inoculation with MHV OBLV closely resemble the disordering of the olfactory epithelium in some patient biopsies. Thus, damage to the olfactory nerve or bulb may contribute to a form of post-viral olfactory dysfunction and MHV OBLV is a useful model for studying the pathogenesis of this form of dysosmia.
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Affiliation(s)
- J E Schwob
- Department of Anatomy and Cellular Biology, Tufts University School of Medicine, Boston, MA 02111, USA.
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