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Saxena A, Mautner J. A Disease Hidden in Plain Sight: Pathways and Mechanisms of Neurological Complications of Post-acute Sequelae of COVID-19 (NC-PASC). Mol Neurobiol 2024:10.1007/s12035-024-04421-z. [PMID: 39133434 DOI: 10.1007/s12035-024-04421-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2024] [Accepted: 08/05/2024] [Indexed: 08/13/2024]
Abstract
The global impact of coronavirus disease 2019 (COVID-19) marked by numerous pandemic peaks is attributed to its high variability and infectious nature, transforming it into a persistent global public health concern. With hundreds of millions of cases reported globally, the illness is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Despite its initial classification as an acute respiratory illness, recent evidence indicates that lingering effects on various bodily systems, such as cardiovascular, pulmonary, nervous, gastrointestinal (GI), and musculoskeletal, may endure well beyond the acute phase. These persistent manifestations following COVID-19, commonly known as long COVID, have the potential to affect individuals across the entire range of illness severity, with a tendency to be more prevalent in mild to moderate cases. At present, there are no established criteria for diagnosing long COVID. Nonetheless, it is conceptualized as a multi-organ disorder encompassing a diverse array of clinical manifestations. The most common, persistent, and debilitating symptoms of long COVID may be neurological, known as neurological complications of post-acute sequelae of COVID-19 (NC-PASC). More than one-third of individuals with a prior SARS-CoV-2 infection show involvement of both the central nervous system (CNS) and peripheral nervous system (PNS), as evidenced by an approximately threefold higher incidence of neurological symptoms in observational studies. The persistent neurological symptoms of long COVID encompass fatigue, headache, cognitive decline, "brain fog", dysautonomia, neuropsychiatric issues, loss of smell (anosmia), loss of taste (ageusia), and peripheral nerve problems (peripheral neuropathy). Reported pathogenic mechanisms encompass viral persistence and neuro-invasion by SARS-CoV-2, neuroinflammation, autoimmunity, coagulopathy, and endotheliopathy. Raising awareness of potential complications is crucial for preventing and alleviating the long-term effects of long COVID and enhancing the prognosis for affected patients. This review explores the hypothetical pathophysiological mechanisms and pathways of NC-PASC with a sole aim to increase awareness about this crippling disease.
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Affiliation(s)
- Apoorva Saxena
- Department of Biology, Ludwig-Maximilians-Universität München, Munich, Germany.
| | - Josef Mautner
- Institute of Virology, Helmholtz Zentrum München, Munich, Germany
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2
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McMillan P, Turner AJ, Uhal BD. Mechanisms of Gut-Related Viral Persistence in Long COVID. Viruses 2024; 16:1266. [PMID: 39205240 PMCID: PMC11360392 DOI: 10.3390/v16081266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2024] [Revised: 07/31/2024] [Accepted: 08/03/2024] [Indexed: 09/04/2024] Open
Abstract
Long COVID (post-acute sequelae of COVID-19-PASC) is a consequence of infection by SARS-CoV-2 that continues to disrupt the well-being of millions of affected individuals for many months beyond their first infection. While the exact mechanisms underlying PASC remain to be defined, hypotheses regarding the pathogenesis of long COVID are varied and include (but are not limited to) dysregulated local or systemic inflammatory responses, autoimmune mechanisms, viral-induced hormonal imbalances, skeletal muscle abnormalities, complement dysregulation, novel abzymes, and long-term persistence of virus and/or fragments of viral RNA or proteins. This review article is based on a comprehensive review of the wide range of symptoms most often observed in long COVID and an attempt to integrate that information into a plausible hypothesis for the pathogenesis of PASC. In particular, it is proposed that long-term dysregulation of the gut in response to viral persistence could lead to the myriad of symptoms observed in PASC.
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Affiliation(s)
| | - Anthony J. Turner
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK;
| | - Bruce D. Uhal
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
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3
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Al-Saigh NN, Harb AA, Abdalla S. Receptors Involved in COVID-19-Related Anosmia: An Update on the Pathophysiology and the Mechanistic Aspects. Int J Mol Sci 2024; 25:8527. [PMID: 39126095 PMCID: PMC11313362 DOI: 10.3390/ijms25158527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2024] [Revised: 07/31/2024] [Accepted: 08/01/2024] [Indexed: 08/12/2024] Open
Abstract
Olfactory perception is an important physiological function for human well-being and health. Loss of olfaction, or anosmia, caused by viral infections such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has received considerable attention, especially in persistent cases that take a long time to recover. This review discusses the integration of different components of the olfactory epithelium to serve as a structural and functional unit and explores how they are affected during viral infections, leading to the development of olfactory dysfunction. The review mainly focused on the role of receptors mediating the disruption of olfactory signal transduction pathways such as angiotensin converting enzyme 2 (ACE2), transmembrane protease serine type 2 (TMPRSS2), neuropilin 1 (NRP1), basigin (CD147), olfactory, transient receptor potential vanilloid 1 (TRPV1), purinergic, and interferon gamma receptors. Furthermore, the compromised function of the epithelial sodium channel (ENaC) induced by SARS-CoV-2 infection and its contribution to olfactory dysfunction are also discussed. Collectively, this review provides fundamental information about the many types of receptors that may modulate olfaction and participate in olfactory dysfunction. It will help to understand the underlying pathophysiology of virus-induced anosmia, which may help in finding and designing effective therapies targeting molecules involved in viral invasion and olfaction. To the best of our knowledge, this is the only review that covered all the receptors potentially involved in, or mediating, the disruption of olfactory signal transduction pathways during COVID-19 infection. This wide and complex spectrum of receptors that mediates the pathophysiology of olfactory dysfunction reflects the many ways in which anosmia can be therapeutically managed.
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Affiliation(s)
- Noor N. Al-Saigh
- Department of Basic Medical Sciences, Faculty of Medicine, Ibn Sina University for Medical Sciences, Amman 16197, Jordan;
| | - Amani A. Harb
- Department of Basic Sciences, Faculty of Arts and Sciences, Al-Ahliyya Amman University, Amman 19111, Jordan;
| | - Shtaywy Abdalla
- Department of Biological Sciences, School of Science, The University of Jordan, Amman 11942, Jordan
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4
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Hamlin RE, Blish CA. Challenges and opportunities in long COVID research. Immunity 2024; 57:1195-1214. [PMID: 38865966 PMCID: PMC11210969 DOI: 10.1016/j.immuni.2024.05.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 04/19/2024] [Accepted: 05/10/2024] [Indexed: 06/14/2024]
Abstract
Long COVID (LC) is a condition in which patients do not fully recover from the initial SARS-CoV-2 infection but rather have persistent or new symptoms for months to years following the infection. Ongoing research efforts are investigating the pathophysiologic mechanisms of LC and exploring preventative and therapeutic treatment approaches for patients. As a burgeoning area of investigation, LC research can be structured to be more inclusive, innovative, and effective. In this perspective, we highlight opportunities for patient engagement and diverse research expertise, as well as the challenges of developing definitions and reproducible studies. Our intention is to provide a foundation for collaboration and progress in understanding the biomarkers and mechanisms driving LC.
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Affiliation(s)
| | - Catherine A Blish
- Department of Medicine, Stanford University, Stanford, CA, USA; Chan Zuckerberg Biohub, San Francisco, CA, USA.
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5
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Kikuta S, Nagayama S, Hasegawa-Ishii S. Structures and functions of the normal and injured human olfactory epithelium. Front Neural Circuits 2024; 18:1406218. [PMID: 38903957 PMCID: PMC11188711 DOI: 10.3389/fncir.2024.1406218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Accepted: 05/20/2024] [Indexed: 06/22/2024] Open
Abstract
The olfactory epithelium (OE) is directly exposed to environmental agents entering the nasal cavity, leaving OSNs prone to injury and degeneration. The causes of olfactory dysfunction are diverse and include head trauma, neurodegenerative diseases, and aging, but the main causes are chronic rhinosinusitis (CRS) and viral infections. In CRS and viral infections, reduced airflow due to local inflammation, inflammatory cytokine production, release of degranulated proteins from eosinophils, and cell injury lead to decreased olfactory function. It is well known that injury-induced loss of mature OSNs in the adult OE causes massive regeneration of new OSNs within a few months through the proliferation and differentiation of progenitor basal cells that are subsequently incorporated into olfactory neural circuits. Although normal olfactory function returns after injury in most cases, prolonged olfactory impairment and lack of improvement in olfactory function in some cases poses a major clinical problem. Persistent inflammation or severe injury in the OE results in morphological changes in the OE and respiratory epithelium and decreases the number of mature OSNs, resulting in irreversible loss of olfactory function. In this review, we discuss the histological structure and distribution of the human OE, and the pathogenesis of olfactory dysfunction associated with CRS and viral infection.
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Affiliation(s)
- Shu Kikuta
- Department of Otolaryngology-Head and Neck Surgery, Faculty of Medicine, Nihon University, Tokyo, Japan
| | - Shin Nagayama
- Department of Neurobiology and Anatomy, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX, United States
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Verma AK, Lowery S, Lin LC, Duraisami E, Lloréns JEA, Qiu Q, Hefti M, Yu CR, Albers MW, Perlman S. Persistent Neurological Deficits in Mouse PASC Reveal Antiviral Drug Limitations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.02.596989. [PMID: 38895239 PMCID: PMC11185538 DOI: 10.1101/2024.06.02.596989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Post-Acute Sequelae of COVID-19 (PASC) encompasses persistent neurological symptoms, including olfactory and autonomic dysfunction. Here, we report chronic neurological dysfunction in mice infected with a virulent mouse-adapted SARS-CoV-2 that does not infect the brain. Long after recovery from nasal infection, we observed loss of tyrosine hydroxylase (TH) expression in olfactory bulb glomeruli and neurotransmitter levels in the substantia nigra (SN) persisted. Vulnerability of dopaminergic neurons in these brain areas was accompanied by increased levels of proinflammatory cytokines and neurobehavioral changes. RNAseq analysis unveiled persistent microglia activation, as found in human neurodegenerative diseases. Early treatment with antivirals (nirmatrelvir and molnupiravir) reduced virus titers and lung inflammation but failed to prevent neurological abnormalities, as observed in patients. Together these results show that chronic deficiencies in neuronal function in SARS-CoV-2-infected mice are not directly linked to ongoing olfactory epithelium dysfunction. Rather, they bear similarity with neurodegenerative disease, the vulnerability of which is exacerbated by chronic inflammation.
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Affiliation(s)
- Abhishek Kumar Verma
- Department of Microbiology and Immunology, University of Iowa, Iowa City, IA 52242
| | - Shea Lowery
- Department of Microbiology and Immunology, University of Iowa, Iowa City, IA 52242
| | - Li-Chin Lin
- Iowa Neuroscience Institute, University of Iowa, IA, USA 52242
- Department of Neurology, University of Iowa, Iowa City, IA 52242
| | | | | | - Qiang Qiu
- Stowers Institute for Medical Research, Kansas City, MO 64110
| | - Marco Hefti
- Department of Pathology, University of Iowa, Iowa City, IA 52242
| | - C. Ron Yu
- Stowers Institute for Medical Research, Kansas City, MO 64110
| | - Mark W. Albers
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Stanley Perlman
- Department of Microbiology and Immunology, University of Iowa, Iowa City, IA 52242
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Li H, Qian J, Wang Y, Wang J, Mi X, Qu L, Song N, Xie J. Potential convergence of olfactory dysfunction in Parkinson's disease and COVID-19: The role of neuroinflammation. Ageing Res Rev 2024; 97:102288. [PMID: 38580172 DOI: 10.1016/j.arr.2024.102288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 03/28/2024] [Accepted: 03/30/2024] [Indexed: 04/07/2024]
Abstract
Parkinson's disease (PD) is a prevalent neurodegenerative disorder that affects 7-10 million individuals worldwide. A common early symptom of PD is olfactory dysfunction (OD), and more than 90% of PD patients suffer from OD. Recent studies have highlighted a high incidence of OD in patients with SARS-CoV-2 infection. This review investigates the potential convergence of OD in PD and COVID-19, particularly focusing on the mechanisms by which neuroinflammation contributes to OD and neurological events. Starting from our fundamental understanding of the olfactory bulb, we summarize the clinical features of OD and pathological features of the olfactory bulb from clinical cases and autopsy reports in PD patients. We then examine SARS-CoV-2-induced olfactory bulb neuropathology and OD and emphasize the SARS-CoV-2-induced neuroinflammatory cascades potentially leading to PD manifestations. By activating microglia and astrocytes, as well as facilitating the aggregation of α-synuclein, SARS-CoV-2 could contribute to the onset or exacerbation of PD. We also discuss the possible contributions of NF-κB, the NLRP3 inflammasome, and the JAK/STAT, p38 MAPK, TLR4, IL-6/JAK2/STAT3 and cGAS-STING signaling pathways. Although olfactory dysfunction in patients with COVID-19 may be reversible, it is challenging to restore OD in patients with PD. With the emergence of new SARS-CoV-2 variants and the recurrence of infections, we call for continued attention to the intersection between PD and SARS-CoV-2 infection, especially from the perspective of OD.
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Affiliation(s)
- Hui Li
- Institute of Brain Science and Disease, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China
| | - Junliang Qian
- Institute of Brain Science and Disease, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China
| | - Youcui Wang
- Institute of Brain Science and Disease, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China
| | - Juan Wang
- Institute of Brain Science and Disease, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China
| | - Xiaoqing Mi
- Institute of Brain Science and Disease, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China
| | - Le Qu
- Institute of Brain Science and Disease, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China
| | - Ning Song
- Institute of Brain Science and Disease, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China.
| | - Junxia Xie
- Institute of Brain Science and Disease, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, China.
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8
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Jagst M, Pottkämper L, Gömer A, Pitarokoili K, Steinmann E. Neuroinvasion and neurotropism of severe acute respiratory syndrome coronavirus 2 infection. Curr Opin Microbiol 2024; 79:102474. [PMID: 38615394 DOI: 10.1016/j.mib.2024.102474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 03/27/2024] [Accepted: 03/28/2024] [Indexed: 04/16/2024]
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019, contributes to neurological pathologies in nearly 30% of patients, extending beyond respiratory symptoms. These manifestations encompass disorders of both the peripheral and central nervous systems, causing among others cerebrovascular issues and psychiatric manifestations during the acute and/or post-acute infection phases. Despite ongoing research, uncertainties persist about the precise mechanism the virus uses to infiltrate the central nervous system and the involved entry portals. This review discusses the potential entry routes, including hematogenous and anterograde transport. Furthermore, we explore variations in neurotropism, neurovirulence, and neurological manifestations among pandemic-associated variants of concern. In conclusion, SARS-CoV-2 can infect numerous cells within the peripheral and central nervous system, provoke inflammatory responses, and induce neuropathological changes.
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Affiliation(s)
- Michelle Jagst
- Department of Molecular and Medical Virology, Ruhr University Bochum, Bochum, Germany; Institute of Virology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Lilli Pottkämper
- Department of Molecular and Medical Virology, Ruhr University Bochum, Bochum, Germany
| | - André Gömer
- Department of Molecular and Medical Virology, Ruhr University Bochum, Bochum, Germany
| | - Kalliopi Pitarokoili
- Department of Neurology, St. Josef Hospital, Ruhr University Bochum, Bochum, Germany
| | - Eike Steinmann
- Department of Molecular and Medical Virology, Ruhr University Bochum, Bochum, Germany; German Centre for Infection Research (DZIF), External Partner Site, Bochum, Germany.
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9
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Dietz A, Senf K, Neuhaus EM. ACKR3 in olfactory glia cells shapes the immune defense of the olfactory mucosa. Glia 2024; 72:1183-1200. [PMID: 38477581 DOI: 10.1002/glia.24527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 03/04/2024] [Accepted: 03/06/2024] [Indexed: 03/14/2024]
Abstract
Barrier-forming olfactory glia cells, termed sustentacular cells, play important roles for immune defense of the olfactory mucosa, for example as entry sites for SARS-CoV-2 and subsequent development of inflammation-induced smell loss. Here we demonstrate that sustentacular cells express ACKR3, a chemokine receptor that functions both as a scavenger of the chemokine CXCL12 and as an activator of alternative signaling pathways. Differential gene expression analysis of bulk RNA sequencing data obtained from WT and ACKR3 conditional knockout mice revealed upregulation of genes involved in immune defense. To map the regulated genes to the different cell types of the olfactory mucosa, we employed biocomputational methods utilizing a single-cell reference atlas. Transcriptome analysis, PCR and immunofluorescence identified up-regulation of NF-κB-related genes, known to amplify inflammatory signaling and to facilitate leukocyte transmigration, in the gliogenic lineage. Accordingly, we found a marked increase in leukocyte-expressed genes and confirmed leukocyte infiltration into the olfactory mucosa. In addition, lack of ACKR3 led to enhanced expression and secretion of early mediators of immune defense by Bowman's glands. As a result, the number of apoptotic cells in the epithelium was decreased. In conclusion, our research underlines the importance of sustentacular cells in immune defense of the olfactory mucosa. Moreover, it identifies ACKR3, a druggable G protein-coupled receptor, as a promising target for modulation of inflammation-associated anosmia.
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Affiliation(s)
- André Dietz
- Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | - Katja Senf
- Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | - Eva M Neuhaus
- Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
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Martin-Lopez E, Brennan B, Mao T, Spence N, Meller SJ, Han K, Yahiaoui N, Wang C, Iwasaki A, Greer CA. Inflammatory Response and Defects on Myelin Integrity in the Olfactory System of K18hACE2 Mice Infected with SARS-CoV-2. eNeuro 2024; 11:ENEURO.0106-24.2024. [PMID: 38834299 PMCID: PMC11185043 DOI: 10.1523/eneuro.0106-24.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 05/09/2024] [Accepted: 05/24/2024] [Indexed: 06/06/2024] Open
Abstract
Viruses, such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), use respiratory epithelial cells as an entry point for infection. Within the nasal cavity, the olfactory epithelium (OE) is particularly sensitive to infections which may lead to olfactory dysfunction. In patients suffering from coronavirus disease 2019, deficits in olfaction have been characterized as a distinctive symptom. Here, we used the K18hACE2 mice to study the spread of SARS-CoV-2 infection and inflammation in the olfactory system (OS) after 7 d of infection. In the OE, we found that SARS-CoV-2 selectively targeted the supporting/sustentacular cells (SCs) and macrophages from the lamina propria. In the brain, SARS-CoV-2 infected some microglial cells in the olfactory bulb (OB), and there was a widespread infection of projection neurons in the OB, piriform cortex (PC), and tubular striatum (TuS). Inflammation, indicated by both elevated numbers and morphologically activated IBA1+ cells (monocyte/macrophage lineages), was preferentially increased in the OE septum, while it was homogeneously distributed throughout the layers of the OB, PC, and TuS. Myelinated OS axonal tracts, the lateral olfactory tract, and the anterior commissure, exhibited decreased levels of 2',3'-cyclic-nucleotide 3'-phosphodiesterase, indicative of myelin defects. Collectively, our work supports the hypothesis that SARS-CoV-2 infected SC and macrophages in the OE and, centrally, microglia and subpopulations of OS neurons. The observed inflammation throughout the OS areas and central myelin defects may account for the long-lasting olfactory deficit.
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Affiliation(s)
- Eduardo Martin-Lopez
- Department of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut 06520-8082
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut 06520-8001
| | - Bowen Brennan
- Department of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut 06520-8082
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut 06520-8001
| | - Tianyang Mao
- Department of Immunobiology, Yale University School of Medicine, The Anlyan Center, New Haven, Connecticut 06520-8043
- Yale University School of Public Health, New Haven, Connecticut 06520-0834
- Howard Hughes Medical Institute, Chevy Chase, Maryland 20815
| | - Natalie Spence
- Department of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut 06520-8082
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut 06520-8001
| | - Sarah J Meller
- Department of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut 06520-8082
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut 06520-8001
- Interdepartmental Neuroscience Program, Yale University School of Medicine, New Haven, Connecticut 06520-8074
| | - Kimberly Han
- Department of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut 06520-8082
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut 06520-8001
| | - Nawal Yahiaoui
- Department of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut 06520-8082
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut 06520-8001
| | - Chelsea Wang
- Department of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut 06520-8082
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut 06520-8001
| | - Akiko Iwasaki
- Department of Immunobiology, Yale University School of Medicine, The Anlyan Center, New Haven, Connecticut 06520-8043
- Yale University School of Public Health, New Haven, Connecticut 06520-0834
- Howard Hughes Medical Institute, Chevy Chase, Maryland 20815
| | - Charles A Greer
- Department of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut 06520-8082
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut 06520-8001
- Interdepartmental Neuroscience Program, Yale University School of Medicine, New Haven, Connecticut 06520-8074
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11
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Wellford SA, Moseman EA. Olfactory immunology: the missing piece in airway and CNS defence. Nat Rev Immunol 2024; 24:381-398. [PMID: 38097777 DOI: 10.1038/s41577-023-00972-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/03/2023] [Indexed: 12/23/2023]
Abstract
The olfactory mucosa is a component of the nasal airway that mediates the sense of smell. Recent studies point to an important role for the olfactory mucosa as a barrier to both respiratory pathogens and to neuroinvasive pathogens that hijack the olfactory nerve and invade the CNS. In particular, the COVID-19 pandemic has demonstrated that the olfactory mucosa is an integral part of a heterogeneous nasal mucosal barrier critical to upper airway immunity. However, our insufficient knowledge of olfactory mucosal immunity hinders attempts to protect this tissue from infection and other diseases. This Review summarizes the state of olfactory immunology by highlighting the unique immunologically relevant anatomy of the olfactory mucosa, describing what is known of olfactory immune cells, and considering the impact of common infectious diseases and inflammatory disorders at this site. We will offer our perspective on the future of the field and the many unresolved questions pertaining to olfactory immunity.
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Affiliation(s)
- Sebastian A Wellford
- Department of Integrative Immunobiology, Duke University School of Medicine, Durham, NC, USA
| | - E Ashley Moseman
- Department of Integrative Immunobiology, Duke University School of Medicine, Durham, NC, USA.
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12
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Shahbaz MA, Kuivanen S, Mussalo L, Afonin AM, Kumari K, Behzadpour D, Kalapudas J, Koivisto AM, Penttilä E, Löppönen H, Jalava P, Vapalahti O, Balistreri G, Lampinen R, Kanninen KM. Exposure to urban particulate matter alters responses of olfactory mucosal cells to SARS-CoV-2 infection. ENVIRONMENTAL RESEARCH 2024; 249:118451. [PMID: 38341073 DOI: 10.1016/j.envres.2024.118451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 02/01/2024] [Accepted: 02/07/2024] [Indexed: 02/12/2024]
Abstract
Respiratory viruses have a significant impact on health, as highlighted by the COVID-19 pandemic. Exposure to air pollution can contribute to viral susceptibility and be associated with severe outcomes, as suggested by recent epidemiological studies. Furthermore, exposure to particulate matter (PM), an important constituent of air pollution, is linked to adverse effects on the brain, including cognitive decline and Alzheimer's disease (AD). The olfactory mucosa (OM), a tissue located at the rooftop of the nasal cavity, is directly exposed to inhaled air and in direct contact with the brain. Increasing evidence of OM dysfunction related to neuropathogenesis and viral infection demonstrates the importance of elucidating the interplay between viruses and air pollutants at the OM. This study examined the effects of subacute exposure to urban PM 0.2 and PM 10-2.5 on SARS-CoV-2 infection using primary human OM cells obtained from cognitively healthy individuals and individuals diagnosed with AD. OM cells were exposed to PM and subsequently infected with the SARS-CoV-2 virus in the presence of pollutants. SARS-CoV-2 entry receptors and replication, toxicological endpoints, cytokine release, oxidative stress markers, and amyloid beta levels were measured. Exposure to PM did not enhance the expression of viral entry receptors or cellular viral load in human OM cells. However, PM-exposed and SARS-CoV-2-infected cells showed alterations in cellular and immune responses when compared to cells infected only with the virus or pollutants. These changes are highly pronounced in AD OM cells. These results suggest that exposure of human OM cells to PM does not increase susceptibility to SARS-CoV-2 infection in vitro, but it can alter cellular immune responses to the virus, particularly in AD. Understanding the interplay of air pollutants and COVID-19 can provide important insight for the development of public health policies and interventions to reduce the negative influences of air pollution exposure.
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Affiliation(s)
- Muhammad Ali Shahbaz
- University of Eastern Finland, A.I. Virtanen Institute for Molecular Sciences, Kuopio, Finland
| | - Suvi Kuivanen
- University of Helsinki, Department of Virology, Faculty of Medicine, Helsinki, Finland; Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Virology, Berlin, Germany
| | - Laura Mussalo
- University of Eastern Finland, A.I. Virtanen Institute for Molecular Sciences, Kuopio, Finland
| | - Alexey M Afonin
- University of Eastern Finland, A.I. Virtanen Institute for Molecular Sciences, Kuopio, Finland
| | - Kajal Kumari
- University of Eastern Finland, A.I. Virtanen Institute for Molecular Sciences, Kuopio, Finland
| | - Donya Behzadpour
- University of Eastern Finland, A.I. Virtanen Institute for Molecular Sciences, Kuopio, Finland
| | - Juho Kalapudas
- University of Eastern Finland, Brain Research Unit, Department of Neurology, School of Medicine, Kuopio, Finland
| | - Anne M Koivisto
- University of Eastern Finland, Brain Research Unit, Department of Neurology, School of Medicine, Kuopio, Finland; Kuopio University Hospital, Department of Neurology, Neuro Centre, Kuopio, Finland; University of Helsinki, Faculty of Medicine, Department of Neurology and Geriatrics, Helsinki University Hospital and Neurosciences, Helsinki, Finland
| | - Elina Penttilä
- University of Eastern Finland and Kuopio University Hospital, Department of Otorhinolaryngology, Kuopio, Finland
| | - Heikki Löppönen
- University of Eastern Finland and Kuopio University Hospital, Department of Otorhinolaryngology, Kuopio, Finland
| | - Pasi Jalava
- University of Eastern Finland, Inhalation Toxicology Laboratory, Department of Environmental and Biological Sciences, Kuopio, Finland
| | - Olli Vapalahti
- University of Helsinki, Department of Virology, Faculty of Medicine, Helsinki, Finland
| | - Giuseppe Balistreri
- University of Helsinki, Department of Virology, Faculty of Medicine, Helsinki, Finland
| | - Riikka Lampinen
- University of Eastern Finland, A.I. Virtanen Institute for Molecular Sciences, Kuopio, Finland
| | - Katja M Kanninen
- University of Eastern Finland, A.I. Virtanen Institute for Molecular Sciences, Kuopio, Finland.
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13
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Abstract
OBJECTIVES The pandemic has affected over 182 million coronavirus disease 2019 (COVID-19) cases worldwide. Accumulated evidence indicates that anosmia is one of the significant characteristics of COVID-19 with a high prevalence. However, many aspects of COVID-19-induced anosmia are still far from being fully understood. The purpose of this review is to summarize recent developments in COVID-19-induced anosmia to increase awareness of the condition. METHODS A literature search was carried out using the PubMed, Embase, Web of Science, and Scopus. We reviewed the latest literature on COVID-19-induced anosmia, including mechanisms of pathogenesis, olfactory testing, anosmia as predictive tool, pathological examinations, imaging findings, affected factors, co-existing diseases, treatments, prognosis, hypothesis theories, and future directions. RESULTS The possible pathogenesis of COVID-19-induced anosmia may involve inflammation of the olfactory clefts and damage to the olfactory epithelium or olfactory central nervous system by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The D614G spike variant may also play a role in the increased number of anosmia patients. Anosmia may also be an essential indicator of COVID-19 spread and an early indicator of the effectiveness of political decisions. The occurrence and development of COVID-19-induced anosmia may be influenced by smoking behaviors and underlying diseases such as type 2 diabetes, gastroesophageal disorders, and rhinitis. Most patients with COVID-19-induced anosmia can fully or partially recover their olfactory function for varying durations. COVID-19-induced anosmia can be treated with various approaches such as glucocorticoids and olfactory training. CONCLUSION Anosmia is one of the main features of COVID-19 and the underlying disease of the patient may also influence its occurrence and development. The possible pathogenesis of COVID-19-induced anosmia is very complicated, which may involve inflammation of the olfactory clefts and damage to the olfactory epithelium or olfactory central nervous system.
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Affiliation(s)
- Xiangming Meng
- Department of Otolaryngology, Wuxi Huishan District People's Hospital, Wuxi, P.R. China
| | - Yuandan Pan
- Department of Respiratory Medicine, Wuxi Huishan District People's Hospital, Wuxi, P.R. China
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14
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Merle-Nguyen L, Ando-Grard O, Bourgon C, St Albin A, Jacquelin J, Klonjkowski B, Le Poder S, Meunier N. Early corticosteroid treatment enhances recovery from SARS-CoV-2 induced loss of smell in hamster. Brain Behav Immun 2024; 118:78-89. [PMID: 38367845 DOI: 10.1016/j.bbi.2024.02.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 02/03/2024] [Accepted: 02/14/2024] [Indexed: 02/19/2024] Open
Abstract
Among the numerous long COVID symptoms, olfactory dysfunction persists in ∼10 % of patients suffering from SARS-CoV-2 induced anosmia. Among the few potential therapies, corticoid treatment has been used for its anti-inflammatory effect with mixed success in patients. In this study, we explored its impact using hamster as an animal model. SARS-CoV-2 infected hamsters lose their smell abilities and this loss is correlated with damage of the olfactory epithelium and persistent presence of innate immunity cells. We started a dexamethasone treatment 2 days post infection, when olfaction was already impacted, until 11 days post infection when it started to recover. We observed an improvement of olfactory capacities in the animals treated with corticoid compared to those treated with vehicle. This recovery was not related to differences in the remaining damage to the olfactory epithelium, which was similar in both groups. This improvement was however correlated with a reduced inflammation in the olfactory epithelium with a local increase of the mature olfactory neuron population. Surprisingly, at 11 days post infection, we observed an increased and disorganized presence of immature olfactory neurons, especially in persistent inflammatory zones of the epithelium. This unusual population of immature olfactory neurons coincided with a strong increase of olfactory epithelium proliferation in both groups. Our results indicate that persistent inflammation of the olfactory epithelium following SARS-CoV-2 infection may alter the extent and speed of regeneration of the olfactory neuron population, and that corticoid treatment is effective to limit inflammation and improve olfaction recovery following SARS-CoV-2 infection.
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Affiliation(s)
- Laetitia Merle-Nguyen
- Unité de Virologie et Immunologie Moléculaires (UR892), INRAE, Université Paris-Saclay, Jouy-en-Josas, France
| | - Ophélie Ando-Grard
- Unité de Virologie et Immunologie Moléculaires (UR892), INRAE, Université Paris-Saclay, Jouy-en-Josas, France
| | - Clara Bourgon
- Unité de Virologie et Immunologie Moléculaires (UR892), INRAE, Université Paris-Saclay, Jouy-en-Josas, France
| | - Audrey St Albin
- Unité de Virologie et Immunologie Moléculaires (UR892), INRAE, Université Paris-Saclay, Jouy-en-Josas, France
| | - Juliette Jacquelin
- Unité de Virologie et Immunologie Moléculaires (UR892), INRAE, Université Paris-Saclay, Jouy-en-Josas, France
| | - Bernard Klonjkowski
- UMR 1161 Virologie, INRAE-ENVA-ANSES, École Nationale Vétérinaire d'Alfort, Maisons-Alfort, 94704 Paris, France
| | - Sophie Le Poder
- UMR 1161 Virologie, INRAE-ENVA-ANSES, École Nationale Vétérinaire d'Alfort, Maisons-Alfort, 94704 Paris, France
| | - Nicolas Meunier
- Unité de Virologie et Immunologie Moléculaires (UR892), INRAE, Université Paris-Saclay, Jouy-en-Josas, France.
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15
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Dell’Aquila M, Cafiero C, Micera A, Stigliano E, Ottaiano MP, Benincasa G, Schiavone B, Guidobaldi L, Santacroce L, Pisconti S, Arena V, Palmirotta R. SARS-CoV-2-Related Olfactory Dysfunction: Autopsy Findings, Histopathology, and Evaluation of Viral RNA and ACE2 Expression in Olfactory Bulbs. Biomedicines 2024; 12:830. [PMID: 38672185 PMCID: PMC11048640 DOI: 10.3390/biomedicines12040830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 03/29/2024] [Accepted: 04/04/2024] [Indexed: 04/28/2024] Open
Abstract
BACKGROUND The COVID-19 pandemic has been a health emergency with a significant impact on the world due to its high infectiousness. The disease, primarily identified in the lower respiratory tract, develops with numerous clinical symptoms affecting multiple organs and displays a clinical finding of anosmia. Several authors have investigated the pathogenetic mechanisms of the olfactory disturbances caused by SARS-CoV-2 infection, proposing different hypotheses and showing contradictory results. Since uncertainties remain about possible virus neurotropism and direct damage to the olfactory bulb, we investigated the expression of SARS-CoV-2 as well as ACE2 receptor transcripts in autoptic lung and olfactory bulb tissues, with respect to the histopathological features. METHODS Twenty-five COVID-19 olfactory bulbs and lung tissues were randomly collected from 200 initial autopsies performed during the COVID-19 pandemic. Routine diagnosis was based on clinical and radiological findings and were confirmed with post-mortem swabs. Real-time RT-PCR for SARS-CoV-2 and ACE2 receptor RNA was carried out on autoptic FFPE lung and olfactory bulb tissues. Histological staining was performed on tissue specimens and compared with the molecular data. RESULTS While real-time RT-PCR for SARS-CoV-2 was positive in 23 out of 25 lung samples, the viral RNA expression was absent in olfactory bulbs. ACE2-receptor RNA was present in all tissues examined, being highly expressed in lung samples than olfactory bulbs. CONCLUSIONS Our finding suggests that COVID-19 anosmia is not only due to neurotropism and the direct action of SARS-CoV-2 entering the olfactory bulb. The mechanism of SARS-CoV-2 neuropathogenesis in the olfactory bulb requires a better elucidation and further research studies to mitigate the olfactory bulb damage associated with virus action.
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Affiliation(s)
- Marco Dell’Aquila
- Anatomic Pathology Unit, Department of Woman and Child Health and Public Health, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (M.D.); (E.S.); (V.A.)
- Pathology Unit, Belcolle Hospital, ASL Viterbo, 01100 Viterbo, Italy
| | - Concetta Cafiero
- Medical Oncology, SG Moscati Hospital, 74010 Statte, Italy;
- Anatomic Pathology Unit, Fabrizio Spaziani Hospital, 03100 Frosinone, Italy
| | - Alessandra Micera
- Research and Development Laboratory for Biochemical, Molecular and Cellular Applications in Ophthalmological Science, IRCCS–Fondazione Bietti, 00184 Rome, Italy
| | - Egidio Stigliano
- Anatomic Pathology Unit, Department of Woman and Child Health and Public Health, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (M.D.); (E.S.); (V.A.)
| | - Maria Pia Ottaiano
- Department of Clinical Pathology and Molecular Biology, Pineta Grande Hospital, 81030 Castel Volturno, Italy; (M.P.O.); (G.B.); (B.S.)
| | - Giulio Benincasa
- Department of Clinical Pathology and Molecular Biology, Pineta Grande Hospital, 81030 Castel Volturno, Italy; (M.P.O.); (G.B.); (B.S.)
| | - Beniamino Schiavone
- Department of Clinical Pathology and Molecular Biology, Pineta Grande Hospital, 81030 Castel Volturno, Italy; (M.P.O.); (G.B.); (B.S.)
| | - Leo Guidobaldi
- Cytodiagnostic Unit, Section of Pathology Sandro Pertini Hospital, ASL Rm2, 00157 Rome, Italy;
| | - Luigi Santacroce
- Section of Microbiology and Virology, Interdisciplinary Department of Medicine, School of Medicine, University of Bari “Aldo Moro”, 70124 Bari, Italy;
| | | | - Vincenzo Arena
- Anatomic Pathology Unit, Department of Woman and Child Health and Public Health, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy; (M.D.); (E.S.); (V.A.)
| | - Raffaele Palmirotta
- Section of Sciences and Technologies of Laboratory Medicine, Interdisciplinary Department of Medicine, School of Medicine, University of Bari “Aldo Moro”, 70124 Bari, Italy;
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16
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Chang K, Zaikos T, Kilner-Pontone N, Ho CY. Mechanisms of COVID-19-associated olfactory dysfunction. Neuropathol Appl Neurobiol 2024; 50:e12960. [PMID: 38419211 PMCID: PMC10906737 DOI: 10.1111/nan.12960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 12/26/2023] [Accepted: 01/08/2024] [Indexed: 03/02/2024]
Abstract
Olfactory dysfunction is one of the most common symptoms of COVID-19. In the first 2 years of the pandemic, it was frequently reported, although its incidence has significantly decreased with the emergence of the Omicron variant, which has since become the dominant viral strain. Nevertheless, many patients continue to suffer from persistent dysosmia and dysgeusia, making COVID-19-associated olfactory dysfunction an ongoing health concern. The proposed pathogenic mechanisms of COVID-19-associated olfactory dysfunction are complex and likely multifactorial. While evidence suggests that infection of sustentacular cells and associated mucosal inflammation may be the culprit of acute, transient smell loss, alterations in other components of the olfactory system (e.g., olfactory receptor neuron dysfunction, olfactory bulb injury and alterations in the olfactory cortex) may lead to persistent, long-term olfactory dysfunction. This review aims to provide a comprehensive summary of the epidemiology, clinical manifestations and current understanding of the pathogenic mechanisms of COVID-19-associated olfactory dysfunction.
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Affiliation(s)
- Koping Chang
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department and Graduate Institute of Pathology, National Taiwan University, Taipei, Taiwan
| | - Thomas Zaikos
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | - Cheng-Ying Ho
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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17
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Butowt R, von Bartheld CS. Timing and cause of olfactory deciliation in COVID-19. Physiol Rev 2024; 104:589-590. [PMID: 38206010 DOI: 10.1152/physrev.00035.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 11/13/2023] [Accepted: 11/15/2023] [Indexed: 01/12/2024] Open
Affiliation(s)
- Rafal Butowt
- Medical Science Center, Faculty of Medicine, Bydgoszcz University of Science and Technology, Bydgoszcz, Poland
| | - Christopher S von Bartheld
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, Reno, Nevada, United States
- Center of Biomedical Research Excellence in Cell Biology, School of Medicine, University of Nevada, Reno, Reno, Nevada, United States
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18
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Marin C, Alobid I, López-Chacón M, VanStrahlen CR, Mullol J. Type 2 and Non-type 2 Inflammation in the Upper Airways: Cellular and Molecular Alterations in Olfactory Neuroepithelium Cell Populations. Curr Allergy Asthma Rep 2024; 24:211-219. [PMID: 38492160 PMCID: PMC11008081 DOI: 10.1007/s11882-024-01137-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/15/2024] [Indexed: 03/18/2024]
Abstract
PURPOSE OF REVIEW Neurogenesis occurring in the olfactory epithelium is critical to continuously replace olfactory neurons to maintain olfactory function, but is impaired during chronic type 2 and non-type 2 inflammation of the upper airways. In this review, we describe the neurobiology of olfaction and the olfactory alterations in chronic rhinosinusitis with nasal polyps (type 2 inflammation) and post-viral acute rhinosinusitis (non-type 2 inflammation), highlighting the role of immune response attenuating olfactory neurogenesis as a possibly mechanism for the loss of smell in these diseases. RECENT FINDINGS Several studies have provided relevant insights into the role of basal stem cells as direct participants in the progression of chronic inflammation identifying a functional switch away from a neuro-regenerative phenotype to one contributing to immune defense, a process that induces a deficient replacement of olfactory neurons. The interaction between olfactory stem cells and immune system might critically underlie ongoing loss of smell in type 2 and non-type 2 inflammatory upper airway diseases. In this review, we describe the neurobiology of olfaction and the olfactory alterations in type 2 and non-type 2 inflammatory upper airway diseases, highlighting the role of immune response attenuating olfactory neurogenesis, as a possibly mechanism for the lack of loss of smell recovery.
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Affiliation(s)
- Concepció Marin
- INGENIO, IRCE, Fundació Recerca Clínic Barcelona-Institut d'Investigacions Biomèdiques August Pi i Sunyer (FRCB-IDIBAPS), Barcelona, Catalonia, Spain.
- Centre for Biomedical Research in Respiratory Diseases (CIBERES), Health Institute Carlos III, Madrid, Spain.
| | - Isam Alobid
- INGENIO, IRCE, Fundació Recerca Clínic Barcelona-Institut d'Investigacions Biomèdiques August Pi i Sunyer (FRCB-IDIBAPS), Barcelona, Catalonia, Spain
- Centre for Biomedical Research in Respiratory Diseases (CIBERES), Health Institute Carlos III, Madrid, Spain
- Rhinology Unit and Smell Clinic, ENT Department, Hospital Clínic, Barcelona, Catalonia, Spain
- Universitat de Barcelona, Barcelona, Spain
| | - Mauricio López-Chacón
- INGENIO, IRCE, Fundació Recerca Clínic Barcelona-Institut d'Investigacions Biomèdiques August Pi i Sunyer (FRCB-IDIBAPS), Barcelona, Catalonia, Spain
- Centre for Biomedical Research in Respiratory Diseases (CIBERES), Health Institute Carlos III, Madrid, Spain
- Rhinology Unit and Smell Clinic, ENT Department, Hospital Clínic, Barcelona, Catalonia, Spain
| | - Camilo R VanStrahlen
- INGENIO, IRCE, Fundació Recerca Clínic Barcelona-Institut d'Investigacions Biomèdiques August Pi i Sunyer (FRCB-IDIBAPS), Barcelona, Catalonia, Spain
- Centre for Biomedical Research in Respiratory Diseases (CIBERES), Health Institute Carlos III, Madrid, Spain
- Rhinology Unit and Smell Clinic, ENT Department, Hospital Clínic, Barcelona, Catalonia, Spain
| | - Joaquim Mullol
- INGENIO, IRCE, Fundació Recerca Clínic Barcelona-Institut d'Investigacions Biomèdiques August Pi i Sunyer (FRCB-IDIBAPS), Barcelona, Catalonia, Spain.
- Centre for Biomedical Research in Respiratory Diseases (CIBERES), Health Institute Carlos III, Madrid, Spain.
- Rhinology Unit and Smell Clinic, ENT Department, Hospital Clínic, Barcelona, Catalonia, Spain.
- Universitat de Barcelona, Barcelona, Spain.
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19
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Chen M, Pekosz A, Villano JS, Shen W, Zhou R, Kulaga H, Li Z, Smith A, Gurung A, Beck SE, Witwer KW, Mankowski JL, Ramanathan M, Rowan NR, Lane AP. Evolution of nasal and olfactory infection characteristics of SARS-CoV-2 variants. J Clin Invest 2024; 134:e174439. [PMID: 38483537 PMCID: PMC11014658 DOI: 10.1172/jci174439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 02/27/2024] [Indexed: 03/26/2024] Open
Abstract
SARS-CoV-2 infection of the upper airway and the subsequent immune response are early, critical factors in COVID-19 pathogenesis. By studying infection of human biopsies in vitro and in a hamster model in vivo, we demonstrated a transition in nasal tropism from olfactory to respiratory epithelium as the virus evolved. Analyzing each variant revealed that SARS-CoV-2 WA1 or Delta infect a proportion of olfactory neurons in addition to the primary target sustentacular cells. The Delta variant possessed broader cellular invasion capacity into the submucosa, while Omicron displayed enhanced nasal respiratory infection and longer retention in the sinonasal epithelium. The olfactory neuronal infection by WA1 and the subsequent olfactory bulb transport via axon were more pronounced in younger hosts. In addition, the observed viral clearance delay and phagocytic dysfunction in aged olfactory mucosa were accompanied by a decline of phagocytosis-related genes. Further, robust basal stem cell activation contributed to neuroepithelial regeneration and restored ACE2 expression postinfection. Together, our study characterized the nasal tropism of SARS-CoV-2 strains, immune clearance, and regeneration after infection. The shifting characteristics of viral infection at the airway portal provide insight into the variability of COVID-19 clinical features, particularly long COVID, and may suggest differing strategies for early local intervention.
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Affiliation(s)
- Mengfei Chen
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Andrew Pekosz
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Baltimore, Maryland, USA
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jason S. Villano
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Wenjuan Shen
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Ruifeng Zhou
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Heather Kulaga
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Zhexuan Li
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Amy Smith
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Asiana Gurung
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Sarah E. Beck
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Kenneth W. Witwer
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Joseph L. Mankowski
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Murugappan Ramanathan
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Nicholas R. Rowan
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Andrew P. Lane
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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20
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Wu C, Xu M, Dong J, Cui W, Yuan S. The structure and function of olfactory receptors. Trends Pharmacol Sci 2024; 45:268-280. [PMID: 38296675 DOI: 10.1016/j.tips.2024.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 01/08/2024] [Accepted: 01/09/2024] [Indexed: 02/02/2024]
Abstract
Olfactory receptors (ORs) form the most important chemosensory receptor family responsible for our sense of smell in the nasal olfactory epithelium. This receptor family belongs to the class A G protein-coupled receptors (GPCRs). Recent research has indicated that ORs are involved in many nonolfactory physiological processes in extranasal tissue, such as the brain, pancreas, and testes, and implies the possible role of their dysregulation in various diseases. The recently released structures of OR51E2 and consensus OR52 have also unveiled the uniqueness of ORs from other class A GPCR members. In this review, we discuss these recent developments and computational modeling efforts toward understanding the structural properties of unresolved ORs, which could guide potential future OR-targeted drug discovery.
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Affiliation(s)
- Chenyang Wu
- The AlphaMol-SIAT Joint Laboratory, Shenzhen 518055, China; The Research Center for Computer-aided Drug Discovery, The Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Marc Xu
- The AlphaMol-SIAT Joint Laboratory, Shenzhen 518055, China; The Research Center for Computer-aided Drug Discovery, The Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Junlin Dong
- The AlphaMol-SIAT Joint Laboratory, Shenzhen 518055, China; The Research Center for Computer-aided Drug Discovery, The Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenqiang Cui
- The AlphaMol-SIAT Joint Laboratory, Shenzhen 518055, China
| | - Shuguang Yuan
- The AlphaMol-SIAT Joint Laboratory, Shenzhen 518055, China; AlphaMol Science Ltd, Shenzhen 518055, China.
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21
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Shimizu S, Nakayama M, Nguyen CT, Ishigaki H, Kitagawa Y, Yasui F, Yagi Y, Kusayanagi T, Kohara M, Itoh Y, Tojima I, Kouzaki H, Shimizu T. SARS-CoV-2 induces inflammation and intracranial infection through the olfactory epithelium-olfactory bulb pathway in non-human primates. J Neuroimmunol 2024; 387:578288. [PMID: 38237527 DOI: 10.1016/j.jneuroim.2024.578288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 12/17/2023] [Accepted: 01/06/2024] [Indexed: 02/12/2024]
Abstract
We examined the histopathological changes in the olfactory mucosa of cynomolgus and rhesus macaque models of SARS-CoV-2 infection. SARS-CoV-2 infection induced severe inflammatory changes in the olfactory mucosa. A major histocompatibility complex (MHC) class II molecule, HLA-DR was expressed in macrophage and supporting cells, and melanocytes were increased in olfactory mucosa. Supporting cells and olfactory neurons were infected, and SARS-CoV-2 N protein was detected in the axons of olfactory neurons and in olfactory bulbs. Viral RNA was detected in olfactory bulbs and brain tissues. The olfactory epithelium-olfactory bulb pathway may be important as a route for intracranial infection by SARS-CoV-2.
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Affiliation(s)
- Shino Shimizu
- Department of Otorhinolaryngology-Head and Neck Surgery, Shiga University of Medical Science, Otsu, Shiga, Japan.
| | - Misako Nakayama
- Division of Pathogenesis and Disease Regulation, Department of Pathology, Shiga University of Medical Science, Otsu, Japan
| | - Cong Thanh Nguyen
- Division of Pathogenesis and Disease Regulation, Department of Pathology, Shiga University of Medical Science, Otsu, Japan
| | - Hirohito Ishigaki
- Division of Pathogenesis and Disease Regulation, Department of Pathology, Shiga University of Medical Science, Otsu, Japan
| | - Yoshinori Kitagawa
- Division of Microbiology and Infectious Disease, Department of Pathology, Shiga University of Medical Science, Otsu, Japan
| | - Fumihiko Yasui
- Department of Microbiology and Cell Biology, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | | | | | - Michinori Kohara
- Department of Microbiology and Cell Biology, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Yasushi Itoh
- Division of Pathogenesis and Disease Regulation, Department of Pathology, Shiga University of Medical Science, Otsu, Japan
| | - Ichiro Tojima
- Department of Otorhinolaryngology-Head and Neck Surgery, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Hideaki Kouzaki
- Department of Otorhinolaryngology-Head and Neck Surgery, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Takeshi Shimizu
- Department of Otorhinolaryngology-Head and Neck Surgery, Shiga University of Medical Science, Otsu, Shiga, Japan
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22
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Simonini L, Frijia F, Ait Ali L, Foffa I, Vecoli C, De Gori C, De Cori S, Baroni M, Aquaro GD, Maremmani C, Lombardo F. A Comprehensive Review of COVID-19-Related Olfactory Deficiency: Unraveling Associations with Neurocognitive Disorders and Magnetic Resonance Imaging Findings. Diagnostics (Basel) 2024; 14:359. [PMID: 38396398 PMCID: PMC10888385 DOI: 10.3390/diagnostics14040359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 01/31/2024] [Accepted: 02/05/2024] [Indexed: 02/25/2024] Open
Abstract
Olfactory dysfunction (OD) is one of the most common symptoms in COVID-19 patients and can impact patients' lives significantly. The aim of this review was to investigate the multifaceted impact of COVID-19 on the olfactory system and to provide an overview of magnetic resonance (MRI) findings and neurocognitive disorders in patients with COVID-19-related OD. Extensive searches were conducted across PubMed, Scopus, and Google Scholar until 5 December 2023. The included articles were 12 observational studies and 1 case report that assess structural changes in olfactory structures, highlighted through MRI, and 10 studies correlating the loss of smell with neurocognitive disorders or mood disorders in COVID-19 patients. MRI findings consistently indicate volumetric abnormalities, altered signal intensity of olfactory bulbs (OBs), and anomalies in the olfactory cortex among COVID-19 patients with persistent OD. The correlation between OD and neurocognitive deficits reveals associations with cognitive impairment, memory deficits, and persistent depressive symptoms. Treatment approaches, including olfactory training and pharmacological interventions, are discussed, emphasizing the need for sustained therapeutic interventions. This review points out several limitations in the current literature while exploring the intricate effects of COVID-19 on OD and its connection to cognitive deficits and mood disorders. The lack of objective olfactory measurements in some studies and potential validity issues in self-reports emphasize the need for cautious interpretation. Our research highlights the critical need for extensive studies with larger samples, proper controls, and objective measurements to deepen our understanding of COVID-19's long-term effects on neurological and olfactory dysfunctions.
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Affiliation(s)
- Ludovica Simonini
- Institute of Clinical Physiology, National Research Council (CNR), 54100 Massa, Italy; (I.F.); (C.V.)
| | - Francesca Frijia
- Bioengineering Unit, Fondazione Toscana G. Monasterio, 56124 Pisa, Italy;
| | - Lamia Ait Ali
- Institute of Clinical Physiology, National Research Council (CNR), 54100 Massa, Italy; (I.F.); (C.V.)
- Pediatric Cardiology and GUCH Unit, Fondazione “G. Monasterio” CNR-Regione Toscana, 54100 Massa, Italy
| | - Ilenia Foffa
- Institute of Clinical Physiology, National Research Council (CNR), 54100 Massa, Italy; (I.F.); (C.V.)
| | - Cecilia Vecoli
- Institute of Clinical Physiology, National Research Council (CNR), 54100 Massa, Italy; (I.F.); (C.V.)
| | - Carmelo De Gori
- Department of Radiology, Fondazione Monasterio/CNR, 56124 Pisa, Italy; (C.D.G.); (S.D.C.); (F.L.)
| | - Sara De Cori
- Department of Radiology, Fondazione Monasterio/CNR, 56124 Pisa, Italy; (C.D.G.); (S.D.C.); (F.L.)
| | - Monica Baroni
- Fondazione “G. Monasterio” CNR-Regione Toscana, 54100 Massa, Italy;
| | - Giovanni Donato Aquaro
- Academic Radiology Unit, Department of Surgical, Medical and Molecular Pathology and Critical Area, University of Pisa, 56124 Pisa, Italy;
| | - Carlo Maremmani
- Unit of Neurology, Ospedale Apuane, Azienda USL Toscana Nord Ovest, 54100 Massa, Italy;
| | - Francesco Lombardo
- Department of Radiology, Fondazione Monasterio/CNR, 56124 Pisa, Italy; (C.D.G.); (S.D.C.); (F.L.)
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23
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Di Pietro C, Haberman AM, Lindenbach BD, Smith PC, Bruscia EM, Allore HG, Vander Wyk B, Tyagi A, Zeiss CJ. Prior Influenza Infection Mitigates SARS-CoV-2 Disease in Syrian Hamsters. Viruses 2024; 16:246. [PMID: 38400021 PMCID: PMC10891789 DOI: 10.3390/v16020246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 01/28/2024] [Accepted: 02/01/2024] [Indexed: 02/25/2024] Open
Abstract
Seasonal infection rates of individual viruses are influenced by synergistic or inhibitory interactions between coincident viruses. Endemic patterns of SARS-CoV-2 and influenza infection overlap seasonally in the Northern hemisphere and may be similarly influenced. We explored the immunopathologic basis of SARS-CoV-2 and influenza A (H1N1pdm09) interactions in Syrian hamsters. H1N1 given 48 h prior to SARS-CoV-2 profoundly mitigated weight loss and lung pathology compared to SARS-CoV-2 infection alone. This was accompanied by the normalization of granulocyte dynamics and accelerated antigen-presenting populations in bronchoalveolar lavage and blood. Using nasal transcriptomics, we identified a rapid upregulation of innate and antiviral pathways induced by H1N1 by the time of SARS-CoV-2 inoculation in 48 h dual-infected animals. The animals that were infected with both viruses also showed a notable and temporary downregulation of mitochondrial and viral replication pathways. Quantitative RT-PCR confirmed a decrease in the SARS-CoV-2 viral load and lower cytokine levels in the lungs of animals infected with both viruses throughout the course of the disease. Our data confirm that H1N1 infection induces rapid and transient gene expression that is associated with the mitigation of SARS-CoV-2 pulmonary disease. These protective responses are likely to begin in the upper respiratory tract shortly after infection. On a population level, interaction between these two viruses may influence their relative seasonal infection rates.
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Affiliation(s)
- Caterina Di Pietro
- Department of Pediatrics, Yale School of Medicine, New Haven, CT 06519, USA; (C.D.P.); (E.M.B.)
| | - Ann M. Haberman
- Department of Immunobiology, Yale School of Medicine, New Haven, CT 06519, USA;
| | - Brett D. Lindenbach
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT 06519, USA;
- Department of Comparative Medicine, Yale School of Medicine, New Haven, CT 06519, USA;
| | - Peter C. Smith
- Department of Comparative Medicine, Yale School of Medicine, New Haven, CT 06519, USA;
| | - Emanuela M. Bruscia
- Department of Pediatrics, Yale School of Medicine, New Haven, CT 06519, USA; (C.D.P.); (E.M.B.)
| | - Heather G. Allore
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT 06519, USA; (H.G.A.); (B.V.W.)
- Department of Biostatistics, Yale School of Public Health, New Haven, CT 06519, USA
| | - Brent Vander Wyk
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT 06519, USA; (H.G.A.); (B.V.W.)
| | - Antariksh Tyagi
- Department of Genetics, Yale Center for Genome Analysis, New Haven, CT 06519, USA;
| | - Caroline J. Zeiss
- Department of Comparative Medicine, Yale School of Medicine, New Haven, CT 06519, USA;
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24
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Rieder AS, Wyse ATS. Regulation of Inflammation by IRAK-M Pathway Can Be Associated with nAchRalpha7 Activation and COVID-19. Mol Neurobiol 2024; 61:581-592. [PMID: 37640915 DOI: 10.1007/s12035-023-03567-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 08/07/2023] [Indexed: 08/31/2023]
Abstract
In spite of the vaccine development and its importance, the SARS-CoV-2 pandemic is still impacting the world. It is known that the COVID-19 severity is related to the cytokine storm phenomenon, being inflammation a common disease feature. The nicotinic cholinergic system has been widely associated with COVID-19 since it plays a protective role in inflammation via nicotinic receptor alpha 7 (nAchRalpha7). In addition, SARS-CoV-2 spike protein (Spro) subunits can interact with nAchRalpha7. Moreover, Spro causes toll-like receptor (TLR) activation, leading to pro- and anti-inflammatory pathways. The increase and maturation of the IL-1 receptor-associated kinase (IRAK) family are mediated by activation of membrane receptors, such as TLRs. IRAK-M, a member of this family, is responsible for negatively regulating the activity of other active IRAKs. In addition, IRAK-M can regulate microglia phenotype by specific protein expression. Furthermore, there exists an antagonist influence of SARS-CoV-2 Spro and the cholinergic system action on the IRAK-M pathway and microglia phenotype. We discuss the overexpression and suppression of IRAK-M in inflammatory cell response to inflammation in SARS-CoV-2 infection when the cholinergic system is constantly activated via nAchRalpha7.
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Affiliation(s)
- Alessanda S Rieder
- Laboratory of Neuroprotection and Neurometabolic Diseases (Wyse's Lab), Department of Biochemistry, ICBS, Universidade Federal Do Rio Grande Do Sul (UFRGS), Rua Ramiro Barcelos, 2600-Anexo, Porto Alegre RS, 90035-003, Brazil
| | - Angela T S Wyse
- Laboratory of Neuroprotection and Neurometabolic Diseases (Wyse's Lab), Department of Biochemistry, ICBS, Universidade Federal Do Rio Grande Do Sul (UFRGS), Rua Ramiro Barcelos, 2600-Anexo, Porto Alegre RS, 90035-003, Brazil.
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25
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Wellford SA, Moseman EA. Olfactory immune response to SARS-CoV-2. Cell Mol Immunol 2024; 21:134-143. [PMID: 38143247 PMCID: PMC10806031 DOI: 10.1038/s41423-023-01119-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 12/04/2023] [Indexed: 12/26/2023] Open
Abstract
Numerous pathogens can infect the olfactory tract, yet the pandemic caused by SARS-CoV-2 has strongly emphasized the importance of the olfactory mucosa as an immune barrier. Situated in the nasal passages, the olfactory mucosa is directly exposed to the environment to sense airborne odorants; however, this also means it can serve as a direct route of entry from the outside world into the brain. As a result, olfactotropic infections can have serious consequences, including dysfunction of the olfactory system, CNS invasion, dissemination to the lower respiratory tract, and transmission between individuals. Recent research has shown that a distinctive immune response is needed to protect this neuronal and mucosal tissue. A better understanding of innate, adaptive, and structural immune barriers in the olfactory mucosa is needed to develop effective therapeutics and vaccines against olfactotropic microbes such as SARS-CoV-2. Here, we summarize the ramifications of SARS-CoV-2 infection of the olfactory mucosa, review the subsequent immune response, and discuss important areas of future research for olfactory immunity to infectious disease.
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Affiliation(s)
- Sebastian A Wellford
- Department of Integrative Immunobiology, Duke University School of Medicine, Durham, NC, USA
| | - E Ashley Moseman
- Department of Integrative Immunobiology, Duke University School of Medicine, Durham, NC, USA.
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26
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Shahbaz MA, Kuivanen S, Lampinen R, Mussalo L, Hron T, Závodná T, Ojha R, Krejčík Z, Saveleva L, Tahir NA, Kalapudas J, Koivisto AM, Penttilä E, Löppönen H, Singh P, Topinka J, Vapalahti O, Chew S, Balistreri G, Kanninen KM. Human-derived air-liquid interface cultures decipher Alzheimer's disease-SARS-CoV-2 crosstalk in the olfactory mucosa. J Neuroinflammation 2023; 20:299. [PMID: 38098019 PMCID: PMC10722731 DOI: 10.1186/s12974-023-02979-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 11/30/2023] [Indexed: 12/17/2023] Open
Abstract
BACKGROUND The neurological effects of the coronavirus disease of 2019 (COVID-19) raise concerns about potential long-term consequences, such as an increased risk of Alzheimer's disease (AD). Neuroinflammation and other AD-associated pathologies are also suggested to increase the risk of serious SARS-CoV-2 infection. Anosmia is a common neurological symptom reported in COVID-19 and in early AD. The olfactory mucosa (OM) is important for the perception of smell and a proposed site of viral entry to the brain. However, little is known about SARS-CoV-2 infection at the OM of individuals with AD. METHODS To address this gap, we established a 3D in vitro model of the OM from primary cells derived from cognitively healthy and AD individuals. We cultured the cells at the air-liquid interface (ALI) to study SARS-CoV-2 infection under controlled experimental conditions. Primary OM cells in ALI expressed angiotensin-converting enzyme 2 (ACE-2), neuropilin-1 (NRP-1), and several other known SARS-CoV-2 receptor and were highly vulnerable to infection. Infection was determined by secreted viral RNA content and confirmed with SARS-CoV-2 nucleocapsid protein (NP) in the infected cells by immunocytochemistry. Differential responses of healthy and AD individuals-derived OM cells to SARS-CoV-2 were determined by RNA sequencing. RESULTS Results indicate that cells derived from cognitively healthy donors and individuals with AD do not differ in susceptibility to infection with the wild-type SARS-CoV-2 virus. However, transcriptomic signatures in cells from individuals with AD are highly distinct. Specifically, the cells from AD patients that were infected with the virus showed increased levels of oxidative stress, desensitized inflammation and immune responses, and alterations to genes associated with olfaction. These results imply that individuals with AD may be at a greater risk of experiencing severe outcomes from the infection, potentially driven by pre-existing neuroinflammation. CONCLUSIONS The study sheds light on the interplay between AD pathology and SARS-CoV-2 infection. Altered transcriptomic signatures in AD cells may contribute to unique symptoms and a more severe disease course, with a notable involvement of neuroinflammation. Furthermore, the research emphasizes the need for targeted interventions to enhance outcomes for AD patients with viral infection. The study is crucial to better comprehend the relationship between AD, COVID-19, and anosmia. It highlights the importance of ongoing research to develop more effective treatments for those at high risk of severe SARS-CoV-2 infection.
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Affiliation(s)
- Muhammad Ali Shahbaz
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70210, Kuopio, Finland
| | - Suvi Kuivanen
- Department of Virology, Faculty of Medicine, University of Helsinki, 00290, Helsinki, Finland
- Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität Zu Berlin, Institute of Virology, 10117, Berlin, Germany
| | - Riikka Lampinen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70210, Kuopio, Finland
| | - Laura Mussalo
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70210, Kuopio, Finland
| | - Tomáš Hron
- Institute of Molecular Genetics, Czech Academy of Sciences, 142 20, Prague, Czech Republic
| | - Táňa Závodná
- Department of Genetic Toxicology and Epigenetics, Institute of Experimental Medicine, Czech Academy of Sciences, 142 20, Prague, Czech Republic
| | - Ravi Ojha
- Department of Virology, Faculty of Medicine, University of Helsinki, 00290, Helsinki, Finland
| | - Zdeněk Krejčík
- Department of Genetic Toxicology and Epigenetics, Institute of Experimental Medicine, Czech Academy of Sciences, 142 20, Prague, Czech Republic
| | - Liudmila Saveleva
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70210, Kuopio, Finland
| | - Numan Ahmad Tahir
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70210, Kuopio, Finland
| | - Juho Kalapudas
- Department of Neurology, Neuro Centre, Kuopio University Hospital, 70210, Kuopio, Finland
| | - Anne M Koivisto
- Department of Neurology, Neuro Centre, Kuopio University Hospital, 70210, Kuopio, Finland
- Brain Research Unit, Department of Neurology, School of Medicine, University of Eastern Finland, 70210, Kuopio, Finland
- Department of Neurology and Geriatrics, Helsinki University Hospital and Neurosciences, Faculty of Medicine, University of Helsinki, 00014, Helsinki, Finland
| | - Elina Penttilä
- Department of Otorhinolaryngology, University of Eastern Finland and Kuopio University Hospital, 70210, Kuopio, Finland
| | - Heikki Löppönen
- Department of Otorhinolaryngology, University of Eastern Finland and Kuopio University Hospital, 70210, Kuopio, Finland
| | | | - Jan Topinka
- Department of Genetic Toxicology and Epigenetics, Institute of Experimental Medicine, Czech Academy of Sciences, 142 20, Prague, Czech Republic
| | - Olli Vapalahti
- Department of Virology, Faculty of Medicine, University of Helsinki, 00290, Helsinki, Finland
| | - Sweelin Chew
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70210, Kuopio, Finland
| | - Giuseppe Balistreri
- Department of Virology, Faculty of Medicine, University of Helsinki, 00290, Helsinki, Finland
- The Queensland Brain Institute, University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Katja M Kanninen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70210, Kuopio, Finland.
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27
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Hu B, Gong M, Xiang Y, Qu S, Zhu H, Ye D. Mechanism and treatment of olfactory dysfunction caused by coronavirus disease 2019. J Transl Med 2023; 21:829. [PMID: 37978386 PMCID: PMC10657033 DOI: 10.1186/s12967-023-04719-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 11/10/2023] [Indexed: 11/19/2023] Open
Abstract
Coronavirus disease 2019 (COVID-19) is an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Since the start of the pandemic, olfactory dysfunction (OD) has been reported as a common symptom of COVID-19. In some asymptomatic carriers, OD is often the first and even the only symptom. At the same time, persistent OD is also a long-term sequela seen after COVID-19 that can have a serious impact on the quality of life of patients. However, the pathogenesis of post-COVID-19 OD is still unclear, and there is no specific treatment for its patients. The aim of this paper was to review the research on OD caused by SARS-CoV-2 infection and to summarize the mechanism of action, the pathogenesis, and current treatments.
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Affiliation(s)
- Bian Hu
- Department of Otorhinolaryngology-Head and Neck Surgery, The Affiliated Lihuili Hospital of Ningbo University, Ningbo, 315040, Zhejiang, China
- Department of Otorhinolaryngology-Head and Neck Surgery, Ninghai First Hospital, Ningbo, 315600, Zhejiang, China
| | - Mengdan Gong
- Department of Otorhinolaryngology-Head and Neck Surgery, The Affiliated Lihuili Hospital of Ningbo University, Ningbo, 315040, Zhejiang, China
| | - Yizhen Xiang
- Department of Otorhinolaryngology-Head and Neck Surgery, The Affiliated Lihuili Hospital of Ningbo University, Ningbo, 315040, Zhejiang, China
| | - Siyuan Qu
- Department of Otorhinolaryngology-Head and Neck Surgery, The Affiliated Lihuili Hospital of Ningbo University, Ningbo, 315040, Zhejiang, China
| | - Hai Zhu
- Department of Otorhinolaryngology-Head and Neck Surgery, The Affiliated Lihuili Hospital of Ningbo University, Ningbo, 315040, Zhejiang, China
| | - Dong Ye
- Department of Otorhinolaryngology-Head and Neck Surgery, The Affiliated Lihuili Hospital of Ningbo University, Ningbo, 315040, Zhejiang, China.
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28
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Zaa CA, Espitia C, Reyes-Barrera KL, An Z, Velasco-Velázquez MA. Neuroprotective Agents with Therapeutic Potential for COVID-19. Biomolecules 2023; 13:1585. [PMID: 38002267 PMCID: PMC10669388 DOI: 10.3390/biom13111585] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 10/19/2023] [Accepted: 10/20/2023] [Indexed: 11/26/2023] Open
Abstract
COVID-19 patients can exhibit a wide range of clinical manifestations affecting various organs and systems. Neurological symptoms have been reported in COVID-19 patients, both during the acute phase of the illness and in cases of long-term COVID. Moderate symptoms include ageusia, anosmia, altered mental status, and cognitive impairment, and in more severe cases can manifest as ischemic cerebrovascular disease and encephalitis. In this narrative review, we delve into the reported neurological symptoms associated with COVID-19, as well as the underlying mechanisms contributing to them. These mechanisms include direct damage to neurons, inflammation, oxidative stress, and protein misfolding. We further investigate the potential of small molecules from natural products to offer neuroprotection in models of neurodegenerative diseases. Through our analysis, we discovered that flavonoids, alkaloids, terpenoids, and other natural compounds exhibit neuroprotective effects by modulating signaling pathways known to be impacted by COVID-19. Some of these compounds also directly target SARS-CoV-2 viral replication. Therefore, molecules of natural origin show promise as potential agents to prevent or mitigate nervous system damage in COVID-19 patients. Further research and the evaluation of different stages of the disease are warranted to explore their potential benefits.
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Affiliation(s)
- César A. Zaa
- School of Biological Sciences, Universidad Nacional Mayor de San Marcos (UNMSM), Lima 15081, Peru;
| | - Clara Espitia
- Department of Immunology, Institute of Biomedical Research, Universidad Nacional Autónoma de México (UNAM), Mexico City 04510, Mexico; (C.E.); (K.L.R.-B.)
| | - Karen L. Reyes-Barrera
- Department of Immunology, Institute of Biomedical Research, Universidad Nacional Autónoma de México (UNAM), Mexico City 04510, Mexico; (C.E.); (K.L.R.-B.)
| | - Zhiqiang An
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center, Houston, TX 77030, USA;
| | - Marco A. Velasco-Velázquez
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center, Houston, TX 77030, USA;
- School of Medicine, Universidad Nacional Autónoma de México (UNAM), Mexico City 04510, Mexico
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29
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Li J, Wang J, Wang H. Emerging Landscape of Preclinical Models for Studying COVID-19 Neurologic Diseases. ACS Pharmacol Transl Sci 2023; 6:1323-1339. [PMID: 37854617 PMCID: PMC10580392 DOI: 10.1021/acsptsci.3c00127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Indexed: 10/20/2023]
Abstract
COVID-19 (Coronavirus Disease 2019) is an infectious disease caused by SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) and has globally infected 768 million people and caused over 6 million deaths. COVID-19 primarily affects the respiratory system but increasing reports of neurologic symptoms associated with COVID-19 have been reported in the literature. The exact mechanism behind COVID-19 neurologic pathophysiology remains poorly understood due to difficulty quantifying clinical neurologic symptoms in humans and correlating them to findings in human post-mortem samples and animal models. Thus, robust preclinical experimental models for COVID-19 neurologic manifestations are urgently needed. Here, we review recent advances in in vitro, in vivo, and other models and technologies for studying COVID-19 including primary cell cultures, pluripotent stem cell-derived neurons and organoids, rodents, nonhuman primates, 3D bioprinting, artificial intelligence, and multiomics. We specifically focus our discussion on the contribution, recent advancements, and limitations these preclinical models have on furthering our understanding of COVID-19's neuropathic physiology. We also discuss these models' roles in the screening and development of therapeutics, vaccines, antiviral drugs, and herbal medicine, and on future opportunities for COVID-19 neurologic research and clinical management.
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Affiliation(s)
- Jason Li
- Department
of Neurology, Indiana University School
of Medicine, Indianapolis, Indiana 46202, United States
| | - Jing Wang
- Department
of Cellular and Molecular Medicine, University
of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Hu Wang
- Institute
of Cell Engineering, School of Medicine, Johns Hopkins University, Baltimore 21215, United States
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30
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Ahmed W, Feng J, Zhang Y, Chen L. SARS-CoV-2 and Brain Health: New Challenges in the Era of the Pandemic. Microorganisms 2023; 11:2511. [PMID: 37894169 PMCID: PMC10609574 DOI: 10.3390/microorganisms11102511] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 09/13/2023] [Accepted: 09/27/2023] [Indexed: 10/29/2023] Open
Abstract
Respiratory viral infections have been found to have a negative impact on neurological functions, potentially leading to significant neurological impairment. The SARS-CoV-2 virus has precipitated a worldwide pandemic, posing a substantial threat to human lives. Growing evidence suggests that SARS-CoV-2 may severely affect the CNS and respiratory system. The current prevalence of clinical neurological issues associated with SARS-CoV-2 has raised significant concerns. However, there needs to be a more comprehensive understanding of the specific pathways by which SARS-CoV-2 enters the nervous system. Based on the available evidence, this review focuses on the clinical neurological manifestations of SARS-CoV-2 and the possible mechanisms by which SARS-CoV-2 invades the brain.
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Affiliation(s)
- Waqas Ahmed
- Department of Neurosurgery, Neuroscience Center, Integrated Hospital of Traditional Chinese Medicine, Southern Medical University, Guangzhou 510310, China
- School of Medicine, Southeast University, Nanjing 210009, China
| | - Jia Feng
- Department of Neurosurgery, Neuroscience Center, Integrated Hospital of Traditional Chinese Medicine, Southern Medical University, Guangzhou 510310, China
- Guangdong Second Provincial General Hospital, Guangzhou 510317, China
| | - Yifan Zhang
- Department of Neurosurgery, Neuroscience Center, Integrated Hospital of Traditional Chinese Medicine, Southern Medical University, Guangzhou 510310, China
| | - Lukui Chen
- Department of Neurosurgery, Neuroscience Center, Integrated Hospital of Traditional Chinese Medicine, Southern Medical University, Guangzhou 510310, China
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31
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Reyna RA, Walker J, Mitchell B, Shinde DP, Plante JA, Weaver SC, Plante KS. Vaccination against SARS-CoV-2 Does Not Protect against the Development of Anosmia in a Hamster Model. Vaccines (Basel) 2023; 11:1564. [PMID: 37896967 PMCID: PMC10611162 DOI: 10.3390/vaccines11101564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 09/29/2023] [Accepted: 10/03/2023] [Indexed: 10/29/2023] Open
Abstract
Anosmia, a total or partial loss of the ability to smell, is one of the most frequently documented sequelae of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. Persistent anosmia is associated with a decrease in quality of life. Here, we assess the impact of virus lineage and vaccination status on anosmia development in the golden Syrian hamster model. To characterize anosmia driven by current variants, we assessed olfactory function in hamsters infected with SARS-CoV-2 lineages A, BA.2, BA.5, BQ.1, and BQ.1.1 using a buried food detection test. We found that significant anosmia occurs upon infection with all variants with a significant correlation between disease severity and degree of anosmia. Moreover, we found that vaccination with either the Pfizer (BNT16b2) or Moderna (mRNA-1273) mRNA vaccines does not protect against anosmia, despite protection against severe disease.
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Affiliation(s)
- Rachel A. Reyna
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA
- World Reference Center for Emerging Viruses and Arboviruses, University of Texas Medical Branch, Galveston, TX 77555, USA (D.P.S.)
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Jordyn Walker
- World Reference Center for Emerging Viruses and Arboviruses, University of Texas Medical Branch, Galveston, TX 77555, USA (D.P.S.)
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Brooke Mitchell
- World Reference Center for Emerging Viruses and Arboviruses, University of Texas Medical Branch, Galveston, TX 77555, USA (D.P.S.)
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Divya P. Shinde
- World Reference Center for Emerging Viruses and Arboviruses, University of Texas Medical Branch, Galveston, TX 77555, USA (D.P.S.)
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Jessica A. Plante
- World Reference Center for Emerging Viruses and Arboviruses, University of Texas Medical Branch, Galveston, TX 77555, USA (D.P.S.)
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Scott C. Weaver
- World Reference Center for Emerging Viruses and Arboviruses, University of Texas Medical Branch, Galveston, TX 77555, USA (D.P.S.)
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Kenneth S. Plante
- World Reference Center for Emerging Viruses and Arboviruses, University of Texas Medical Branch, Galveston, TX 77555, USA (D.P.S.)
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX 77555, USA
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32
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Tsukahara T, Brann DH, Datta SR. Mechanisms of SARS-CoV-2-associated anosmia. Physiol Rev 2023; 103:2759-2766. [PMID: 37342077 PMCID: PMC10625840 DOI: 10.1152/physrev.00012.2023] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 06/05/2023] [Accepted: 06/15/2023] [Indexed: 06/22/2023] Open
Abstract
Anosmia, the loss of the sense of smell, is one of the main neurological manifestations of COVID-19. Although the SARS-CoV-2 virus targets the nasal olfactory epithelium, current evidence suggests that neuronal infection is extremely rare in both the olfactory periphery and the brain, prompting the need for mechanistic models that can explain the widespread anosmia in COVID-19 patients. Starting from work identifying the non-neuronal cell types that are infected by SARS-CoV-2 in the olfactory system, we review the effects of infection of these supportive cells in the olfactory epithelium and in the brain and posit the downstream mechanisms through which sense of smell is impaired in COVID-19 patients. We propose that indirect mechanisms contribute to altered olfactory system function in COVID-19-associated anosmia, as opposed to neuronal infection or neuroinvasion into the brain. Such indirect mechanisms include tissue damage, inflammatory responses through immune cell infiltration or systemic circulation of cytokines, and downregulation of odorant receptor genes in olfactory sensory neurons in response to local and systemic signals. We also highlight key unresolved questions raised by recent findings.
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Affiliation(s)
- Tatsuya Tsukahara
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, United States
| | - David H Brann
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, United States
| | - Sandeep Robert Datta
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, United States
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Martončíková M, Doležal P, Fabianová K, Karhánek M, Gálik J, Raček A, Popovičová A, Račeková E. Remote psychophysical testing of smell in patients with persistent olfactory dysfunction after COVID-19. Sci Rep 2023; 13:14090. [PMID: 37640847 PMCID: PMC10462624 DOI: 10.1038/s41598-023-41395-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 08/25/2023] [Indexed: 08/31/2023] Open
Abstract
Olfactory dysfunction associated with coronavirus 2 (SARS-CoV-2) infection is in most cases transient, recovering spontaneously within a few days. However, in some patients it persists for a long time, affects their everyday life and endangers their health. Hence, we focused on patients with persistent loss of smell. The aim of this study was to evaluate olfactory dysfunction using a standardized test. Due to the pandemic, olfactory testing was performed online. Smell tests (Odorized Markers Test, OMT) were sent home to the patients. Together with the smell self-testing, participants reported and assessed several parameters (age, sex, subjective assessment of smell and taste, nasal patency, etc.) in an online questionnaire. Based on the questionnaire outcomes, the results were sent to the patients along with a list of participating otolaryngologists who provided them with professional care. From March to June 2021, 1025 patients requested smell testing, of these, 824 met the inclusion criteria of this study. The duration of the olfactory dysfunction at the time of testing ranged from 1 month to 1 year. Using the OMT, impaired smell ability-anosmia or hyposmia-was confirmed in 82.6% of participants. A total of 17.4% of participants were determined to be normosmic however, more than 50% of them complained of parosmia and/or phantosmia. Our study demonstrates the relevance of psychophysical smell testing and its suitability for remote use during the pandemic. This study also revealed several correlations between prolonged olfactory dysfunction and the monitored parameters.
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Affiliation(s)
- Marcela Martončíková
- Institute of Neurobiology, Biomedical Research Center, Slovak Academy of Sciences, Šoltésovej 4, 040 01, Košice, Slovakia
| | - Pavel Doležal
- Department of Otorhinolaryngology and Head and Neck Surgery, University Hospital-St. Michal's Hospital, Slovak Medical University, Bratislava, Slovakia
| | - Kamila Fabianová
- Institute of Neurobiology, Biomedical Research Center, Slovak Academy of Sciences, Šoltésovej 4, 040 01, Košice, Slovakia
| | - Miloslav Karhánek
- Laboratory of Bioinformatics, Biomedical Research Center, Slovak Academy of Sciences, Dúbravská Cesta 9, 845 05, Bratislava, Slovakia
| | - Ján Gálik
- Institute of Neurobiology, Biomedical Research Center, Slovak Academy of Sciences, Šoltésovej 4, 040 01, Košice, Slovakia
| | - Adam Raček
- Institute of Neurobiology, Biomedical Research Center, Slovak Academy of Sciences, Šoltésovej 4, 040 01, Košice, Slovakia
| | - Alexandra Popovičová
- Institute of Neurobiology, Biomedical Research Center, Slovak Academy of Sciences, Šoltésovej 4, 040 01, Košice, Slovakia
| | - Enikő Račeková
- Institute of Neurobiology, Biomedical Research Center, Slovak Academy of Sciences, Šoltésovej 4, 040 01, Košice, Slovakia.
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Verro B, Vivoli G, Saraniti C. Hyposmia in COVID-19: Temporal Recovery of Smell: A Preliminary Study. MEDICINA (KAUNAS, LITHUANIA) 2023; 59:1511. [PMID: 37763630 PMCID: PMC10535790 DOI: 10.3390/medicina59091511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 08/07/2023] [Accepted: 08/21/2023] [Indexed: 09/29/2023]
Abstract
Background and Objectives: Hypo/anosmia is a characteristic symptom of COVID-19 infection. The aim of this study is to investigate the time of smell recovery and to identify a possible order of perception recovery of different odors in COVID-19 patients. Materials and Methods: A prospective observational study was conducted on not hospitalized COVID-19 patients, selected according to eligible criteria. The study was approved by the Ethical Committee. A questionnaire formulated by our team was submitted to patients in order to know the duration of the hypo/anosmia and hypo/ageusia and the order of odor recovery: vanillin (mixed olfactory/gustatory substances), phenyl ethyl alcohol (rosewater) (pure olfactory substances), eucalyptol (mixed olfactory/trigeminal substances), and eugenol (mixed olfactory/trigeminal/gustatory substances). Results: 181 patients were included. Hypo/ageusia and hypo/anosmia lasted on average 10.25 (±8.26) and 12.8 (±8.80) days, respectively. The most frequent odor recovery sequence was: (1) phenyl ethyl alcohol; (2) eucalyptol; (3) vanillin; and (4) eugenol. In COVID-19 patients, hypo/anosmia occurs more often in women and at a young age. Conclusions: This preliminary investigation highlighted novel data: there is a chronological order in perception recovery of different olfactory substances and, therefore, in the restoration of the various sensitive nerve pathways involved in the sense of smell.
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Affiliation(s)
- Barbara Verro
- Division of Otorhinolaryngology, Department of Biomedicine, Neuroscience and Advanced Diagnostic, University of Palermo, 90127 Palermo, Italy;
| | - Giulia Vivoli
- Division of Plastic, Reconstructive, Microvascular and Aesthetic Surgery, Department of Maternal-Infant and Adult Surgical Medical Sciences, University of Modena and Reggio Emilia, 41121 Modena, Italy;
| | - Carmelo Saraniti
- Division of Otorhinolaryngology, Department of Biomedicine, Neuroscience and Advanced Diagnostic, University of Palermo, 90127 Palermo, Italy;
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de Melo GD, Perraud V, Alvarez F, Vieites-Prado A, Kim S, Kergoat L, Coleon A, Trüeb BS, Tichit M, Piazza A, Thierry A, Hardy D, Wolff N, Munier S, Koszul R, Simon-Lorière E, Thiel V, Lecuit M, Lledo PM, Renier N, Larrous F, Bourhy H. Neuroinvasion and anosmia are independent phenomena upon infection with SARS-CoV-2 and its variants. Nat Commun 2023; 14:4485. [PMID: 37495586 PMCID: PMC10372078 DOI: 10.1038/s41467-023-40228-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 07/11/2023] [Indexed: 07/28/2023] Open
Abstract
Anosmia was identified as a hallmark of COVID-19 early in the pandemic, however, with the emergence of variants of concern, the clinical profile induced by SARS-CoV-2 infection has changed, with anosmia being less frequent. Here, we assessed the clinical, olfactory and neuroinflammatory conditions of golden hamsters infected with the original Wuhan SARS-CoV-2 strain, its isogenic ORF7-deletion mutant and three variants: Gamma, Delta, and Omicron/BA.1. We show that infected animals develop a variant-dependent clinical disease including anosmia, and that the ORF7 of SARS-CoV-2 contributes to the induction of olfactory dysfunction. Conversely, all SARS-CoV-2 variants are neuroinvasive, regardless of the clinical presentation they induce. Taken together, this confirms that neuroinvasion and anosmia are independent phenomena upon SARS-CoV-2 infection. Using newly generated nanoluciferase-expressing SARS-CoV-2, we validate the olfactory pathway as a major entry point into the brain in vivo and demonstrate in vitro that SARS-CoV-2 travels retrogradely and anterogradely along axons in microfluidic neuron-epithelial networks.
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Affiliation(s)
- Guilherme Dias de Melo
- Institut Pasteur, Université Paris Cité, Lyssavirus Epidemiology and Neuropathology Unit, F-75015, Paris, France
| | - Victoire Perraud
- Institut Pasteur, Université Paris Cité, Lyssavirus Epidemiology and Neuropathology Unit, F-75015, Paris, France
| | - Flavio Alvarez
- Institut Pasteur, Université Paris Cité, Channel Receptors Unit, F-75015, Paris, France
- Sorbonne Université, Collège Doctoral, F-75005, Paris, France
| | - Alba Vieites-Prado
- Institut du Cerveau et de la Moelle Épinière, Laboratoire de Plasticité Structurale, , Sorbonne Université, INSERM U1127, CNRS UMR7225, 75013, Paris, France
| | - Seonhee Kim
- Institut Pasteur, Université Paris Cité, Lyssavirus Epidemiology and Neuropathology Unit, F-75015, Paris, France
| | - Lauriane Kergoat
- Institut Pasteur, Université Paris Cité, Lyssavirus Epidemiology and Neuropathology Unit, F-75015, Paris, France
| | - Anthony Coleon
- Institut Pasteur, Université Paris Cité, Lyssavirus Epidemiology and Neuropathology Unit, F-75015, Paris, France
| | - Bettina Salome Trüeb
- Institute of Virology and Immunology (IVI), Bern, Switzerland; Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Magali Tichit
- Institut Pasteur, Université Paris Cité, Histopathology Platform, F-75015, Paris, France
| | - Aurèle Piazza
- Institut Pasteur, Université Paris Cité, Spatial Regulation of Genomes Laboratory, F-75015, Paris, France
| | - Agnès Thierry
- Institut Pasteur, Université Paris Cité, Spatial Regulation of Genomes Laboratory, F-75015, Paris, France
| | - David Hardy
- Institut Pasteur, Université Paris Cité, Histopathology Platform, F-75015, Paris, France
| | - Nicolas Wolff
- Institut Pasteur, Université Paris Cité, Channel Receptors Unit, F-75015, Paris, France
| | - Sandie Munier
- Institut Pasteur, Université Paris Cité, Molecular Genetics of RNA viruses Unit, F-75015, Paris, France
| | - Romain Koszul
- Institut Pasteur, Université Paris Cité, Spatial Regulation of Genomes Laboratory, F-75015, Paris, France
| | - Etienne Simon-Lorière
- Institut Pasteur, Université Paris Cité, Evolutionary Genomics of RNA Viruses Group, F-75015, Paris, France
| | - Volker Thiel
- Multidisciplinary Center for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Marc Lecuit
- Institut Pasteur, Université Paris Cité, Inserm U1117, Biology of Infection Unit, 75015, Paris, France
- Necker-Enfants Malades University Hospital, Division of Infectious Diseases and Tropical Medicine, APHP, Institut Imagine, 75006, Paris, France
| | - Pierre-Marie Lledo
- Institut Pasteur, Université Paris Cité, Perception and Memory Unit, F-75015 Paris, France; CNRS UMR3571, 75015, Paris, France
| | - Nicolas Renier
- Institut du Cerveau et de la Moelle Épinière, Laboratoire de Plasticité Structurale, , Sorbonne Université, INSERM U1127, CNRS UMR7225, 75013, Paris, France
| | - Florence Larrous
- Institut Pasteur, Université Paris Cité, Lyssavirus Epidemiology and Neuropathology Unit, F-75015, Paris, France
| | - Hervé Bourhy
- Institut Pasteur, Université Paris Cité, Lyssavirus Epidemiology and Neuropathology Unit, F-75015, Paris, France.
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Liu ZY, Vaira LA, Boscolo-Rizzo P, Walker A, Hopkins C. Post-viral olfactory loss and parosmia. BMJ MEDICINE 2023; 2:e000382. [PMID: 37841969 PMCID: PMC10568123 DOI: 10.1136/bmjmed-2022-000382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 05/26/2023] [Indexed: 10/17/2023]
Abstract
The emergence of SARS-CoV-2 has brought olfactory dysfunction to the forefront of public awareness, because up to half of infected individuals could develop olfactory dysfunction. Loss of smell-which can be partial or total-in itself is debilitating, but the distortion of sense of smell (parosmia) that can occur as a consequence of a viral upper respiratory tract infection (either alongside a reduction in sense of smell or as a solo symptom) can be very distressing for patients. Incidence of olfactory loss after SARS-CoV-2 infection has been estimated by meta-analysis to be around 50%, with more than one in three who will subsequently report parosmia. While early loss of sense of smell is thought to be due to infection of the supporting cells of the olfactory epithelium, the underlying mechanisms of persistant loss and parosmia remain less clear. Depletion of olfactory sensory neurones, chronic inflammatory infiltrates, and downregulation of receptor expression are thought to contribute. There are few effective therapeutic options, so support and olfactory training are essential. Further research is required before strong recommendations can be made to support treatment with steroids, supplements, or interventions applied topically or injected into the olfactory epithelium in terms of improving recovery of quantitative olfactory function. It is not yet known whether these treatments will also achieve comparable improvements in parosmia. This article aims to contextualise parosmia in the setting of post-viral olfactory dysfunction, explore some of the putative molecular mechanisms, and review some of the treatment options available.
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Affiliation(s)
- Zhen Yu Liu
- Department of ENT Surgery, Royal Brisbane and Women's Hospital, Herston, QLD, Australia
| | - Luigi Angelo Vaira
- Department of Medicine, Surgery and Pharmacy, University of Sassari, Sassari, Sardegna, Italy
| | - Paolo Boscolo-Rizzo
- Department of Medical, Surgical, and Health Sciences, Section of Otolaryngology, University of Trieste, Trieste, Italy
| | - Abigail Walker
- Department of ENT, Royal Brisbane and Women's Hospital, Herston, QLD, Australia
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Chen S, Wang S. The immune mechanism of the nasal epithelium in COVID-19-related olfactory dysfunction. Front Immunol 2023; 14:1045009. [PMID: 37529051 PMCID: PMC10387544 DOI: 10.3389/fimmu.2023.1045009] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 06/29/2023] [Indexed: 08/03/2023] Open
Abstract
During the first waves of the coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, olfactory dysfunction (OD) was reported as a frequent clinical sign. The nasal epithelium is one of the front-line protections against viral infections, and the immune responses of the nasal mucosa may be associated with OD. Two mechanisms underlying OD occurrence in COVID-19 have been proposed: the infection of sustentacular cells and the inflammatory reaction of the nasal epithelium. The former triggers OD and the latter likely prolongs OD. These two alternative mechanisms may act in parallel; the infection of sustentacular cells is more important for OD occurrence because sustentacular cells are more likely to be the entry point of SARS-CoV-2 than olfactory neurons and more susceptible to early injury. Furthermore, sustentacular cells abundantly express transmembrane protease, serine 2 (TMPRSS2) and play a major role in the olfactory epithelium. OD occurrence in COVID-19 has revealed crucial roles of sustentacular cells. This review aims to elucidate how immune responses of the nasal epithelium contribute to COVID-19-related OD. Understanding the underlying immune mechanisms of the nasal epithelium in OD may aid in the development of improved medical treatments for COVID-19-related OD.
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Affiliation(s)
| | - Shufen Wang
- *Correspondence: Shunmei Chen, ; Shufen Wang,
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Lupi L, Bordin A, Sales G, Colaianni D, Vitiello A, Biscontin A, Reale A, Garzino-Demo A, Antonini A, Ottaviano G, Mucignat C, Parolin C, Calistri A, De Pittà C. Persistent and transient olfactory deficits in COVID-19 are associated to inflammation and zinc homeostasis. Front Immunol 2023; 14:1148595. [PMID: 37520523 PMCID: PMC10380959 DOI: 10.3389/fimmu.2023.1148595] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 06/29/2023] [Indexed: 08/01/2023] Open
Abstract
Introduction The Coronavirus Disease 2019 (COVID-19) is mainly a respiratory syndrome that can affect multiple organ systems, causing a variety of symptoms. Among the most common and characteristic symptoms are deficits in smell and taste perception, which may last for weeks/months after COVID-19 diagnosis owing to mechanisms that are not fully elucidated. Methods In order to identify the determinants of olfactory symptom persistence, we obtained olfactory mucosa (OM) from 21 subjects, grouped according to clinical criteria: i) with persistent olfactory symptoms; ii) with transient olfactory symptoms; iii) without olfactory symptoms; and iv) non-COVID-19 controls. Cells from the olfactory mucosa were harvested for transcriptome analyses. Results and discussion RNA-Seq assays showed that gene expression levels are altered for a long time after infection. The expression profile of micro RNAs appeared significantly altered after infection, but no relationship with olfactory symptoms was found. On the other hand, patients with persistent olfactory deficits displayed increased levels of expression of genes involved in the inflammatory response and zinc homeostasis, suggesting an association with persistent or transient olfactory deficits in individuals who experienced SARS-CoV-2 infection.
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Affiliation(s)
- Lorenzo Lupi
- Department of Biology, University of Padova, Padova, Italy
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Anna Bordin
- Department of Neurosciences, Otolaryngology Section, University of Padova, Padova, Italy
| | - Gabriele Sales
- Department of Biology, University of Padova, Padova, Italy
| | | | - Adriana Vitiello
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | | | - Alberto Reale
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Alfredo Garzino-Demo
- Department of Molecular Medicine, University of Padova, Padova, Italy
- Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, Maryland, United States
| | - Angelo Antonini
- Parkinson and Movement Disorders Unit, Department of Neurosciences, University of Padova, Padova, Italy
- Department of Neurosciences, University of Padova, Padova, Italy
| | - Giancarlo Ottaviano
- Department of Neurosciences, Otolaryngology Section, University of Padova, Padova, Italy
| | - Carla Mucignat
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Cristina Parolin
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Arianna Calistri
- Department of Molecular Medicine, University of Padova, Padova, Italy
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Howe de la Torre S, Parlatini V, Cortese S. Long-term central nervous system (CNS) consequences of COVID-19 in children. Expert Rev Neurother 2023; 23:703-720. [PMID: 37545414 DOI: 10.1080/14737175.2023.2239500] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 07/18/2023] [Indexed: 08/08/2023]
Abstract
INTRODUCTION Neurological/neuropsychiatric symptoms are commonly reported by children/young people with long COVID, especially headache, fatigue, cognitive deficits, anosmia and ageusia, dizziness, mood symptoms, and sleep problems. However, reported prevalence estimates are highly variable due to study heterogeneity and often small sample size; most studies only considered short-term follow-ups; and, apart from mood and sleep problems, neuropsychiatric conditions have received less attention. Considering the potential debilitating effects of neurological/neuropsychiatric conditions, a comprehensive review of the topic is timely, and needed to support clinical recognition as well as to set the direction for future research. AREAS COVERED The authors discuss neurological/neuropsychiatric manifestations of long COVID in pediatric populations, with a focus on prevalence, associated demographic characteristics, and potential pathogenetic mechanisms. EXPERT OPINION Children/young people may develop persistent neurological/neuropsychiatric symptoms following acute SARS-CoV-2 infection, which may affect daily functioning and well-being. Studies in larger samples with longer follow-ups are needed to clarify prevalence and symptom duration; as well as less investigated risk factors, including genetic predisposition, ethnicity, and comorbidities. Controlled studies may help separate infection-related direct effects from pandemic-related psychosocial stressors. Clarifying pathogenetic mechanisms is paramount to develop more targeted and effective treatments; whilst screening programs and psychoeducation may enhance early recognition.
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Affiliation(s)
| | - Valeria Parlatini
- Department of Child and Adolescent Psychiatry, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Samuele Cortese
- School of Psychology, University of Southampton, Southampton, UK
- Horizon Centre, CAMHS West, William Macleod Way, Solent NHS Trust, Southampton, UK
- Division of Psychiatry and Applied Psychology, School of Medicine, University of Nottingham, Nottingham, UK
- Hassenfeld Children's Hospital at NYU Langone, New York University Child Study Center, New York City, New York, USA
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Hamed SA, Ahmed MAAR. The effectiveness of cerebrolysin, a multi-modal neurotrophic factor, for treatment of post-covid-19 persistent olfactory, gustatory and trigeminal chemosensory dysfunctions: a randomized clinical trial. Expert Rev Clin Pharmacol 2023; 16:1261-1276. [PMID: 37950370 DOI: 10.1080/17512433.2023.2282715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 11/07/2023] [Indexed: 11/12/2023]
Abstract
BACKGROUND This trial aimed to monitor the outcomes of persistent post-covid-19 smell and taste disorders after cerebrolysin therapy, a NTF, and olfactory and gustatory trainings. RESEARCH DESIGN AND METHODS This was a prospective randomized trial. It included 250 patients (male = 93, female = 157; age: 31.3 ± 8.9 years). Patients were randomized into group 1 (n = 150): received cerebrolysin [5 ml/d (IM), 5d/week] and practiced olfactory and gustatory trainings, and group 2 (n = 100): practiced olfactory and gustatory trainings only, for ≥ 8-24 weeks. Measures of outcomes were: a clinical questionnaire; sniffin' odor, taste and flavor identification tests; and global rating scales for smell and taste. RESULTS The duration of disorders was 11.7 ± 3.7mo (range: 6-24mo). The majority (n = 167; 66.8%) developed parosmia within months (3.6 ± 2.7mo) after anosmia. Objective testing showed anosmia in all and taste, flavor, and trigeminal sensory losses in 18% (n = 45). Analyses for secondary outcome were done on 202 patients (group 1 = 130; group 2 = 72). Recovery was complete in 61.5% (n = 80) with cerebrolysin therapy and partial in 17% (n = 22). There was no recovery with trainings only. There were no predictors for recovery. CONCLUSIONS Cerebrolysin had fast, promising, and constant effect, with cure rate of > 60%. This might be due to its ability to initiate and enhance neuronal regeneration and reorganization of sensory epithelia. TRIAL REGISTRATION NCT04830943.
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Affiliation(s)
- Sherifa Ahmed Hamed
- Department of Neurology and Psychiatry, Assiut University Hospital, Assiut, Egypt
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Song J, Wang M, Wang C, Zhang L. Olfactory dysfunction in chronic rhinosinusitis: insights into the underlying mechanisms and treatments. Expert Rev Clin Immunol 2023; 19:993-1004. [PMID: 37432663 DOI: 10.1080/1744666x.2023.2235891] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 07/07/2023] [Indexed: 07/12/2023]
Abstract
INTRODUCTION Olfactory dysfunction (OD) is a typical symptom of chronic rhinosinusitis (CRS), which adversely affects the patient's quality of life and results in mood depression. Studies investigating the impairment of olfactory epithelium (OE) have indicated that inflammation-induced cell damage and dysfunction in OE plays a vital role in the development of OD. Consequently, glucocorticoids and biologics are beneficial in the management of OD in CRS patients. However, the mechanisms underlying OE impairment in CRS patients have not been fully elucidated. AREAS COVERED This review focuses on mechanisms underlying inflammation-induced cell impairment in OE of CRS patients. Additionally, the methods used for detection of olfaction and both currently available and potentially new clinical treatments for OD are reviewed. EXPERT OPINION Chronic inflammation in OE impairs not only olfactory sensory neurons but also non-neuronal cells that are responsible for regeneration and support for neurons. The current treatment for OD in CRS is mainly aimed at attenuating and preventing inflammation. Strategies for use of combinations of these therapies may achieve greater efficacy in restoration of the damaged OE and consequently better management of OD.
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Affiliation(s)
- Jing Song
- Department of Otolaryngology, Head and Neck Surgery, Beijing TongRen Hospital, Capital Medical University, Beijing, China
| | - Ming Wang
- Department of Otolaryngology, Head and Neck Surgery, Beijing TongRen Hospital, Capital Medical University, Beijing, China
- Beijing Key Laboratory of Nasal Diseases, Beijing Laboratory of Allergic Diseases, Beijing Institute of Otolaryngology, Beijing, China
| | - Chengshuo Wang
- Department of Otolaryngology, Head and Neck Surgery, Beijing TongRen Hospital, Capital Medical University, Beijing, China
- Beijing Key Laboratory of Nasal Diseases, Beijing Laboratory of Allergic Diseases, Beijing Institute of Otolaryngology, Beijing, China
| | - Luo Zhang
- Department of Otolaryngology, Head and Neck Surgery, Beijing TongRen Hospital, Capital Medical University, Beijing, China
- Beijing Key Laboratory of Nasal Diseases, Beijing Laboratory of Allergic Diseases, Beijing Institute of Otolaryngology, Beijing, China
- Department of Allergy, Beijing TongRen Hospital, Capital Medical University, Beijing, China
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Chung TWH, Zhang H, Wong FKC, Sridhar S, Lee TMC, Leung GKK, Chan KH, Lau KK, Tam AR, Ho DTY, Cheng VCC, Yuen KY, Hung IFN, Mak HKF. A Pilot Study of Short-Course Oral Vitamin A and Aerosolised Diffuser Olfactory Training for the Treatment of Smell Loss in Long COVID. Brain Sci 2023; 13:1014. [PMID: 37508945 PMCID: PMC10377650 DOI: 10.3390/brainsci13071014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 06/20/2023] [Accepted: 06/27/2023] [Indexed: 07/30/2023] Open
Abstract
Background: Olfactory dysfunction (OD) is a common neurosensory manifestation in long COVID. An effective and safe treatment against COVID-19-related OD is needed. Methods: This pilot trial recruited long COVID patients with persistent OD. Participants were randomly assigned to receive short-course (14 days) oral vitamin A (VitA; 25,000 IU per day) and aerosolised diffuser olfactory training (OT) thrice daily (combination), OT alone (standard care), or observation (control) for 4 weeks. The primary outcome was differences in olfactory function by butanol threshold tests (BTT) between baseline and end-of-treatment. Secondary outcomes included smell identification tests (SIT), structural MRI brain, and serial seed-based functional connectivity (FC) analyses in the olfactory cortical network by resting-state functional MRI (rs-fMRI). Results: A total of 24 participants were randomly assigned to receive either combination treatment (n = 10), standard care (n = 9), or control (n = 5). Median OD duration was 157 days (IQR 127-175). Mean baseline BTT score was 2.3 (SD 1.1). At end-of-treatment, mean BTT scores were significantly higher for the combination group than control (p < 0.001, MD = 4.4, 95% CI 1.7 to 7.2) and standard care (p = 0.009) groups. Interval SIT scores increased significantly (p = 0.009) in the combination group. rs-fMRI showed significantly higher FC in the combination group when compared to other groups. At end-of-treatment, positive correlations were found in the increased FC at left inferior frontal gyrus and clinically significant improvements in measured BTT (r = 0.858, p < 0.001) and SIT (r = 0.548, p = 0.042) scores for the combination group. Conclusions: Short-course oral VitA and aerosolised diffuser OT was effective as a combination treatment for persistent OD in long COVID.
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Affiliation(s)
- Tom Wai-Hin Chung
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Hui Zhang
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong, China
- Research Institute for Intelligent Wearable Systems, The Hong Kong Polytechnic University, Hong Kong, China
| | - Fergus Kai-Chuen Wong
- Department of Ear, Nose and Throat, Pamela Youde Nethersole Eastern Hospital, Hong Kong, China
| | - Siddharth Sridhar
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
- State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong, China
- Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong, China
| | - Tatia Mei-Chun Lee
- Department of Psychology, The University of Hong Kong, Hong Kong, China
- State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, China
| | - Gilberto Ka-Kit Leung
- Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Koon-Ho Chan
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Kui-Kai Lau
- State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, China
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Anthony Raymond Tam
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Deborah Tip-Yin Ho
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Vincent Chi-Chung Cheng
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Kwok-Yung Yuen
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
- State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong, China
- Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong, China
- The Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The University of Hong Kong, Hong Kong, China
| | - Ivan Fan-Ngai Hung
- Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong, China
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
- The Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The University of Hong Kong, Hong Kong, China
| | - Henry Ka-Fung Mak
- State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, China
- Department of Diagnostic Radiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
- Alzheimer's Disease Research Network, The University of Hong Kong, Hong Kong, China
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Hamed SA, Kamal-Eldeen EB, Ahmed MAAR. Evaluation of children and adults with post-COVID-19 persistent smell, taste and trigeminal chemosensory disorders: A hospital based study. World J Clin Pediatr 2023; 12:133-150. [PMID: 37342446 PMCID: PMC10278074 DOI: 10.5409/wjcp.v12.i3.133] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/16/2023] [Accepted: 04/20/2023] [Indexed: 06/08/2023] Open
Abstract
BACKGROUND Smell disorders are the most frequent persistent coronavirus disease 2019 (COVID-19) complications.
AIM To describe the patterns and characteristics of persistent smell and taste disorders in Egyptian patients.
METHODS Assessment was done to 185 patients (adults = 150, age: 31.41 ± 8.63 years; children = 35; age: 15.66 ± 1.63 years). Otolaryngology and neuropsychiatric evaluations were done. Measurements included: A clinical questionnaire (for smell and taste); sniffin' odor, taste and flavor identification tests and the Questionnaire of Olfactory Disorders-Negative Statements (sQOD-NS).
RESULTS Duration of disorders was 11.53 ± 3.97 ms (6-24 ms). Parosmia (n = 119; 64.32%) was developed months after anosmia (3.05 ± 1.87 ms). Objective testing showed anosmia in all, ageusia and flavor loss in 20% (n = 37) and loss of nasal and oral trigeminal sensations in 18% (n = 33) and 20% (n = 37), respectively. Patients had low scoring of sQOD-NS (11.41 ± 3.66). There were no specific differences in other demographics and clinical variables which could distinguish post-COVID-19 smell and taste disorders in children from adults.
CONCLUSION The course of small and taste disorders are supportive of the nasal and oral neuronal compromises. Post-COVID-19 taste and trigeminal disorders were less frequent compared to smell disorders. Post-COVID-19 flavor disorders were solely dependent on taste and not smell disorders. There were no demographics, clinical variables at onset or specific profile of these disorders in children compared to adults.
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Affiliation(s)
- Sherifa Ahmed Hamed
- Department of Neurology and Psychiatry, Assiut University, Faculty of Medicine, Assiut 71516, Egypt
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Palmieri M, Pozzer D, Landsberger N. Advanced genetic therapies for the treatment of Rett syndrome: state of the art and future perspectives. Front Neurosci 2023; 17:1172805. [PMID: 37304036 PMCID: PMC10248472 DOI: 10.3389/fnins.2023.1172805] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 05/02/2023] [Indexed: 06/13/2023] Open
Abstract
Loss and gain of functions mutations in the X-linked MECP2 (methyl-CpG-binding protein 2) gene are responsible for a set of generally severe neurological disorders that can affect both genders. In particular, Mecp2 deficiency is mainly associated with Rett syndrome (RTT) in girls, while duplication of the MECP2 gene leads, mainly in boys, to the MECP2 duplication syndrome (MDS). No cure is currently available for MECP2 related disorders. However, several studies have reported that by re-expressing the wild-type gene is possible to restore defective phenotypes of Mecp2 null animals. This proof of principle endorsed many laboratories to search for novel therapeutic strategies to cure RTT. Besides pharmacological approaches aimed at modulating MeCP2-downstream pathways, genetic targeting of MECP2 or its transcript have been largely proposed. Remarkably, two studies focused on augmentative gene therapy were recently approved for clinical trials. Both use molecular strategies to well-control gene dosage. Notably, the recent development of genome editing technologies has opened an alternative way to specifically target MECP2 without altering its physiological levels. Other attractive approaches exclusively applicable for nonsense mutations are the translational read-through (TR) and t-RNA suppressor therapy. Reactivation of the MECP2 locus on the silent X chromosome represents another valid choice for the disease. In this article, we intend to review the most recent genetic interventions for the treatment of RTT, describing the current state of the art, and the related advantages and concerns. We will also discuss the possible application of other advanced therapies, based on molecular delivery through nanoparticles, already proposed for other neurological disorders but still not tested in RTT.
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Affiliation(s)
- Michela Palmieri
- Rett Research Unit, Division of Neuroscience, San Raffaele Hospital (IRCCS), Milan, Italy
| | - Diego Pozzer
- Rett Research Unit, Division of Neuroscience, San Raffaele Hospital (IRCCS), Milan, Italy
| | - Nicoletta Landsberger
- Rett Research Unit, Division of Neuroscience, San Raffaele Hospital (IRCCS), Milan, Italy
- Department of Medical Biotechnology and Translational Medicine, Faculty of Medicine and Surgery, University of Milan, Milan, Italy
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Hamed SA. Post-COVID-19 persistent olfactory, gustatory, and trigeminal chemosensory disorders: Definitions, mechanisms, and potential treatments. World J Otorhinolaryngol 2023; 10:4-22. [DOI: 10.5319/wjo.v10.i2.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 03/28/2023] [Accepted: 04/18/2023] [Indexed: 05/08/2023] Open
Abstract
The nose and the oral cavities are the main sites for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) entry into the body. Smell and taste deficits are the most common acute viral manifestations. Persistent smell disorders are the most common and bothersome complications after SARS-CoV-2 infection, lasting for months to years. The mechanisms and treatment of persistent post-coronavirus disease 2019 (COVID-19) smell and taste disorders are still challenges. Information sources for the review are PubMed, Centers for Disease Control and Prevention, Ovid Medline, Embase, Scopus, Web of Science, International Prospective Register of Systematic Reviews, Cumulative Index to Nursing and Allied Health Literature, Elton Bryson Stephens Company, Cochrane Effective Practice and Organization of Care, Cooperation in Science and Technology, International Clinical Trials Registry Platform, World Health Organization, Randomized Controlled Trial Number Registry, and MediFind. This review summarizes the up-to-date information about the prevalence, patterns at onset, and prognoses of post-COVID-19 smell and taste disorders, evidence for the neurotropism of SARS-CoV-2 and the overlap between SARS-CoV-1, Middle East respiratory syndrome coronavirus, and SARS-CoV-2 in structure, molecular biology, mode of replication, and host pathogenicity, the suggested cellular and molecular mechanisms for these post-COVID19 chemosensory disorders, and the applied pharmacotherapies and interventions as trials to treat these disorders, and the recommendations for future research to improve understanding of predictors and mechanisms of these disorders. These are crucial for hopeful proper treatment strategies.
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Affiliation(s)
- Sherifa Ahmed Hamed
- Department of Neurology and Psychiatry, Assiut University, Faculty of Medicine, Assiut 71516, Egypt
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Tan ZW, Toong PJ, Guarnera E, Berezovsky IN. Disrupted chromatin architecture in olfactory sensory neurons: looking for the link from COVID-19 infection to anosmia. Sci Rep 2023; 13:5906. [PMID: 37041182 PMCID: PMC10088727 DOI: 10.1038/s41598-023-32896-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 04/04/2023] [Indexed: 04/13/2023] Open
Abstract
We tackle here genomic mechanisms of a rapid onset and recovery from anosmia-a potential diagnostic indicator for early-stage COVID-19 infection. Based on previous observations on how olfactory receptor (OR) gene expression is regulated via chromatin structure in mice, we hypothesized that the disruption of the OR gene expression and, respectively, deficiency of the OR function can be caused by chromatin reorganization taking place upon SARS-CoV-2 infection. We obtained chromatin ensemble reconstructions from COVID-19 patients and control samples using our original computational framework for the whole-genome 3D chromatin ensemble reconstruction. Specifically, we used megabase-scale structural units and effective interactions between them obtained in the Markov State modelling of the Hi-C contact network as an unput in the stochastic embedding procedure of the whole-genome 3D chromatin ensemble reconstruction. We have also developed here a new procedure for analyzing fine structural hierarchy with (sub)TAD-size units in local chromatin regions, which we apply here to parts of chromosomes containing OR genes and corresponding regulatory elements. We observed structural modifications in COVID-19 patients on different levels of chromatin organization, from the alteration of whole genome structure and chromosomal intermingling to reorganization of contacts between chromatin loops at the level of topologically associating domains. While complementary data on known regulatory elements point to potential pathology-associated changes within the overall picture of chromatin alterations, further investigation using additional epigenetic factors mapped on 3D reconstructions with improved resolution will be required for better understanding of anosmia caused by SARS-CoV-2 infection.
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Affiliation(s)
- Zhen Wah Tan
- Agency for Science, Technology and Research (A*STAR), Bioinformatics Institute (BII), 30 Biopolis Street, Matrix, Singapore, 138671, Republic of Singapore
| | - Ping Jing Toong
- Agency for Science, Technology and Research (A*STAR), Bioinformatics Institute (BII), 30 Biopolis Street, Matrix, Singapore, 138671, Republic of Singapore
| | - Enrico Guarnera
- Agency for Science, Technology and Research (A*STAR), Bioinformatics Institute (BII), 30 Biopolis Street, Matrix, Singapore, 138671, Republic of Singapore
- Computational Drug Discovery, EMD Serono Research and Development Institute, Merck KGaA, 45A Middlesex Tpke, Billerica, MA, 01821, USA
| | - Igor N Berezovsky
- Agency for Science, Technology and Research (A*STAR), Bioinformatics Institute (BII), 30 Biopolis Street, Matrix, Singapore, 138671, Republic of Singapore.
- Department of Biological Sciences (DBS), National University of Singapore (NUS), 8 Medical Drive, Singapore, 117597, Singapore.
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Daniel M, Charier D, Pereira B, Pachcinski M, Sharshar T, Molliex S. Prognosis value of pupillometry in COVID-19 patients admitted in intensive care unit. Auton Neurosci 2023; 245:103057. [PMID: 36549090 PMCID: PMC9758063 DOI: 10.1016/j.autneu.2022.103057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 10/26/2022] [Accepted: 12/07/2022] [Indexed: 12/23/2022]
Abstract
INTRODUCTION ICU patients with SARS-CoV-2-related pneumonia are at risk to develop a central dysautonomia which can contribute to mortality and respiratory failure. The pupillary size and its reactivity to light are controlled by the autonomic nervous system. Pupillometry parameters (PP) allow to predict outcomes in various acute brain injuries. We aim at assessing the most predictive PP of in-hospital mortality and the need for invasive mechanical ventilation (IV). MATERIAL AND METHODS We led a prospective, two centers, observational study. We recruited adult patients admitted to ICU for a severe SARS-CoV-2 related pneumonia between April and August 2020. The pupillometry was performed at admission including the measurement of baseline pupillary diameter (PD), PD variations (PDV), pupillary constriction velocity (PCV) and latency (PDL). RESULTS Fifty patients, 90 % males, aged 66 (60-70) years were included. Seven (14 %) patients died in hospital. The baseline PD (4.1 mm [3.5; 4.8] vs 2.6 mm [2.4; 4.0], P = 0.009), PDV (33 % [27; 39] vs 25 % [15; 36], P = 0.03) and PCV (3.5 mm.s-1 [2.8; 4.4] vs 2.0 mm.s-1 [1.9; 3.8], P = 0.02) were significantly lower in patients who will die. A PD value <2.75 mm was the most predictive parameter of in-hospital mortality, with an AUC = 0.81, CI 95 % [0.63; 0.99]. Twenty-four (48 %) patients required IV. PD and PDV were significantly lower in patients who were intubated (3.5 mm [2.8; 4.4] vs 4.2 mm [3.9; 5.2], P = 0.03; 28 % [25; 36 %] vs 35 % [32; 40], P = 0.049, respectively). CONCLUSIONS A reduced baseline PD is associated with bad outcomes in COVID-19 patients admitted in ICU. It is likely to reflect a brainstem autonomic dysfunction.
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Affiliation(s)
- Matthieu Daniel
- Medical and Surgical Neurointensive Care Unit, Hôpital Sainte-Anne, GHU Paris Psychiatrie et Neurosciences, Paris, France; University of Paris, Paris, France.
| | - David Charier
- Anesthesia and Intensive Care Department & Sainbiose INSERM Unité 1059, Université Jean Monnet, Saint-Etienne, France
| | - Bruno Pereira
- Department of Clinical Research and Innovation, CHU of Clermont-Ferrand, Clermont-Ferrand, France
| | | | - Tarek Sharshar
- Medical and Surgical Neurointensive Care Unit, Hôpital Sainte-Anne, GHU Paris Psychiatrie et Neurosciences, Paris, France,Department of Infection and Epidemiology, Pasteur Institute, University of Paris, Paris, France
| | - Serge Molliex
- Anesthesia and Intensive Care Department & Sainbiose INSERM Unité 1059, Université Jean Monnet, Saint-Etienne, France
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Yang J, Luly KM, Green JJ. Nonviral nanoparticle gene delivery into the CNS for neurological disorders and brain cancer applications. WILEY INTERDISCIPLINARY REVIEWS. NANOMEDICINE AND NANOBIOTECHNOLOGY 2023; 15:e1853. [PMID: 36193561 PMCID: PMC10023321 DOI: 10.1002/wnan.1853] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 05/24/2022] [Accepted: 08/11/2022] [Indexed: 03/15/2023]
Abstract
Nonviral nanoparticles have emerged as an attractive alternative to viral vectors for gene therapy applications, utilizing a range of lipid-based, polymeric, and inorganic materials. These materials can either encapsulate or be functionalized to bind nucleic acids and protect them from degradation. To effectively elicit changes to gene expression, the nanoparticle carrier needs to undergo a series of steps intracellularly, from interacting with the cellular membrane to facilitate cellular uptake to endosomal escape and nucleic acid release. Adjusting physiochemical properties of the nanoparticles, such as size, charge, and targeting ligands, can improve cellular uptake and ultimately gene delivery. Applications in the central nervous system (CNS; i.e., neurological diseases, brain cancers) face further extracellular barriers for a gene-carrying nanoparticle to surpass, with the most significant being the blood-brain barrier (BBB). Approaches to overcome these extracellular challenges to deliver nanoparticles into the CNS include systemic, intracerebroventricular, intrathecal, and intranasal administration. This review describes and compares different biomaterials for nonviral nanoparticle-mediated gene therapy to the CNS and explores challenges and recent preclinical and clinical developments in overcoming barriers to nanoparticle-mediated delivery to the brain. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Neurological Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.
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Affiliation(s)
- Joanna Yang
- Departments of Biomedical Engineering, Ophthalmology, Oncology, Neurosurgery, Materials Science & Engineering, and Chemical & Biomolecular Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Kathryn M Luly
- Departments of Biomedical Engineering, Ophthalmology, Oncology, Neurosurgery, Materials Science & Engineering, and Chemical & Biomolecular Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jordan J Green
- Departments of Biomedical Engineering, Ophthalmology, Oncology, Neurosurgery, Materials Science & Engineering, and Chemical & Biomolecular Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Do SARS-CoV-2 Variants Differ in Their Neuropathogenicity? mBio 2023; 14:e0292022. [PMID: 36651750 PMCID: PMC9973339 DOI: 10.1128/mbio.02920-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Neurological complications associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections are a huge societal problem. Although the neuropathogenicity of SARS-CoV-2 is not yet fully understood, there is evidence that SARS-CoV-2 can invade and infect cells of the central nervous system. Kong et al. (https://doi.org/10.1128/mbio.02308-22) shows that the mechanism of virus entry into astrocytes in brain organoids and primary astrocytes differs from entry into respiratory epithelial cells. However, how SARS-CoV-2 enters susceptible CNS cells and whether there are differences among SARS-CoV-2 variants is still unclear. In vivo and in vitro models are useful to study these important questions and may reveal important differences among SARS-CoV-2 variants in their neuroinvasive, neurotropic, and neurovirulent potential. In this commentary we address how this study contributes to the understanding of the neuropathology of SARS-CoV-2 and its variants.
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Bhatia-Dey N, Csoka AB, Heinbockel T. Chemosensory Ability and Sensitivity in Health and Disease: Epigenetic Regulation and COVID-19. Int J Mol Sci 2023; 24:ijms24044179. [PMID: 36835589 PMCID: PMC9959623 DOI: 10.3390/ijms24044179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 02/13/2023] [Accepted: 02/17/2023] [Indexed: 02/22/2023] Open
Abstract
Throughout the animal kingdom, our two chemical senses, olfaction and gustation, are defined by two primary factors: genomic architecture of the organisms and their living environment. During the past three years of the global COVID-19 pandemic, these two sensory modalities have drawn much attention at the basic science and clinical levels because of the strong association of olfactory and gustatory dysfunction with viral infection. Loss of our sense of smell alone, or together with a loss of taste, has emerged as a reliable indicator of COVID-19 infection. Previously, similar dysfunctions have been detected in a large cohort of patients with chronic conditions. The research focus remains on understanding the persistence of olfactory and gustatory disturbances in the post-infection phase, especially in cases with long-term effect of infection (long COVID). Also, both sensory modalities show consistent age-related decline in studies aimed to understand the pathology of neurodegenerative conditions. Some studies using classical model organisms show an impact on neural structure and behavior in offspring as an outcome of parental olfactory experience. The methylation status of specific odorant receptors, activated in parents, is passed on to the offspring. Furthermore, experimental evidence indicates an inverse correlation of gustatory and olfactory abilities with obesity. Such diverse lines of evidence emerging from basic and clinical research studies indicate a complex interplay of genetic factors, evolutionary forces, and epigenetic alterations. Environmental factors that regulate gustation and olfaction could induce epigenetic modulation. However, in turn, such modulation leads to variable effects depending on genetic makeup and physiological status. Therefore, a layered regulatory hierarchy remains active and is passed on to multiple generations. In the present review, we attempt to understand the experimental evidence that indicates variable regulatory mechanisms through multilayered and cross-reacting pathways. Our analytical approach will add to enhancement of prevailing therapeutic interventions and bring to the forefront the significance of chemosensory modalities for the evaluation and maintenance of long-term health.
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