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Kai N, Nishida N, Aoishi K, Takagi T, Hato N. Effect of intranasal administration of concentrated growth factors on regeneration of the olfactory epithelium in an olfactory dysfunction-induced rat model. PLoS One 2024; 19:e0298640. [PMID: 38416730 PMCID: PMC10901354 DOI: 10.1371/journal.pone.0298640] [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: 10/17/2023] [Accepted: 01/26/2024] [Indexed: 03/01/2024] Open
Abstract
OBJECTIVE The development of treatments that promote the regenerative capacity of the olfactory epithelium (OE) is desirable. This study aimed to evaluate the effects of intranasal administration of concentrated growth factors (CGFs) in a rat model of olfactory dysfunction. STUDY DESIGN Animal study. METHODS Nineteen male rats were used. Fourteen olfactory dysfunction models were created by intraperitoneal administration of 3-methylindole. We randomly divided the rats from the olfactory dysfunction model after 1 week into the CGF or saline group; CGFs were administered to seven animals and saline to seven animals. Behavioral assessments using the avoidance test were conducted until day 28 after CGF/saline administration. On day 28, histological evaluation was conducted to determine olfactory epithelial thickness and the olfactory marker protein (OMP)-positive cell count. Five animals were intraperitoneally injected with saline as the control group. RESULTS The avoidance rate remained decreased until 28 days after CGF/saline administration, and there was no significant difference between the two groups. Olfactory epithelial thicknesses on day 28 were 38.64 ± 3.17 μm and 32.84 ± 4.50 μm in the CGF and saline groups, respectively. OE thickness was significantly thicker in the CGF group than in the saline group (P = 0.013). The numbers of OMP-positive cells were 40.29 ± 9.77/1.0 × 104 μm2 and 31.00 ± 3.69/1.0 × 104 μm2 in the CGF and saline groups, respectively. The number of OMP+ cells in the CGF group was significantly increased compared with that in the saline group (P = 0.009). Both groups showed no improvement compared with the control group (OE thickness: 54.08 ± 3.36 μm; OMP+ cell count: 56.90 ± 9.91/1.0 × 104 μm2). CONCLUSIONS The CGF group showed improved olfactory epithelial thickness and OMP-positive cell numbers compared with that in the saline group.
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Affiliation(s)
- Naruhiko Kai
- Department of Otolaryngology, Head and Neck Surgery, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, Japan
| | - Naoya Nishida
- Department of Otolaryngology, Head and Neck Surgery, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, Japan
- Department of Otolaryngology, Ehime Prefectural Niihama Hospital, Niihama, Japan
| | - Kunihide Aoishi
- Department of Otolaryngology, Head and Neck Surgery, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, Japan
| | - Taro Takagi
- Department of Otolaryngology, Head and Neck Surgery, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, Japan
| | - Naohito Hato
- Department of Otolaryngology, Head and Neck Surgery, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime, Japan
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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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3
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Patel ZM, Holbrook EH, Turner JH, Adappa ND, Albers MW, Altundag A, Appenzeller S, Costanzo RM, Croy I, Davis GE, Dehgani-Mobaraki P, Doty RL, Duffy VB, Goldstein BJ, Gudis DA, Haehner A, Higgins TS, Hopkins C, Huart C, Hummel T, Jitaroon K, Kern RC, Khanwalkar AR, Kobayashi M, Kondo K, Lane AP, Lechner M, Leopold DA, Levy JM, Marmura MJ, Mclelland L, Miwa T, Moberg PJ, Mueller CA, Nigwekar SU, O'Brien EK, Paunescu TG, Pellegrino R, Philpott C, Pinto JM, Reiter ER, Roalf DR, Rowan NR, Schlosser RJ, Schwob J, Seiden AM, Smith TL, Soler ZM, Sowerby L, Tan BK, Thamboo A, Wrobel B, Yan CH. International consensus statement on allergy and rhinology: Olfaction. Int Forum Allergy Rhinol 2022; 12:327-680. [PMID: 35373533 DOI: 10.1002/alr.22929] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 01/01/2021] [Accepted: 11/19/2021] [Indexed: 12/11/2022]
Abstract
BACKGROUND The literature regarding clinical olfaction, olfactory loss, and olfactory dysfunction has expanded rapidly over the past two decades, with an exponential rise in the past year. There is substantial variability in the quality of this literature and a need to consolidate and critically review the evidence. It is with that aim that we have gathered experts from around the world to produce this International Consensus on Allergy and Rhinology: Olfaction (ICAR:O). METHODS Using previously described methodology, specific topics were developed relating to olfaction. Each topic was assigned a literature review, evidence-based review, or evidence-based review with recommendations format as dictated by available evidence and scope within the ICAR:O document. Following iterative reviews of each topic, the ICAR:O document was integrated and reviewed by all authors for final consensus. RESULTS The ICAR:O document reviews nearly 100 separate topics within the realm of olfaction, including diagnosis, epidemiology, disease burden, diagnosis, testing, etiology, treatment, and associated pathologies. CONCLUSION This critical review of the existing clinical olfaction literature provides much needed insight and clarity into the evaluation, diagnosis, and treatment of patients with olfactory dysfunction, while also clearly delineating gaps in our knowledge and evidence base that we should investigate further.
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Affiliation(s)
- Zara M Patel
- Otolaryngology, Stanford University School of Medicine, Stanford, California, USA
| | - Eric H Holbrook
- Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, USA
| | - Justin H Turner
- Otolaryngology, Vanderbilt School of Medicine, Nashville, Tennessee, USA
| | - Nithin D Adappa
- Otolaryngology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Mark W Albers
- Neurology, Harvard Medical School, Boston, Massachusetts, USA
| | - Aytug Altundag
- Otolaryngology, Biruni University School of Medicine, İstanbul, Turkey
| | - Simone Appenzeller
- Rheumatology, School of Medical Sciences, University of Campinas, São Paulo, Brazil
| | - Richard M Costanzo
- Physiology and Biophysics and Otolaryngology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, USA
| | - Ilona Croy
- Psychology and Psychosomatic Medicine, TU Dresden, Dresden, Germany
| | - Greg E Davis
- Otolaryngology, Proliance Surgeons, Seattle and Puyallup, Washington, USA
| | - Puya Dehgani-Mobaraki
- Associazione Naso Sano, Umbria Regional Registry of Volunteer Activities, Corciano, Italy
| | - Richard L Doty
- Smell and Taste Center, Otolaryngology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Valerie B Duffy
- Allied Health Sciences, University of Connecticut, Storrs, Connecticut, USA
| | | | - David A Gudis
- Otolaryngology, Columbia University Irving Medical Center, New York, USA
| | - Antje Haehner
- Smell and Taste, Otolaryngology, TU Dresden, Dresden, Germany
| | - Thomas S Higgins
- Otolaryngology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Claire Hopkins
- Otolaryngology, Guy's and St. Thomas' Hospitals, London Bridge Hospital, London, UK
| | - Caroline Huart
- Otorhinolaryngology, Cliniques universitaires Saint-Luc, Institute of Neuroscience, Université catholgique de Louvain, Brussels, Belgium
| | - Thomas Hummel
- Smell and Taste, Otolaryngology, TU Dresden, Dresden, Germany
| | | | - Robert C Kern
- Otolaryngology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Ashoke R Khanwalkar
- Otolaryngology, Stanford University School of Medicine, Stanford, California, USA
| | - Masayoshi Kobayashi
- Otorhinolaryngology-Head and Neck Surgery, Mie University Graduate School of Medicine, Mie, Japan
| | - Kenji Kondo
- Otolaryngology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
| | - Andrew P Lane
- Otolaryngology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Matt Lechner
- Otolaryngology, Barts Health and University College London, London, UK
| | - Donald A Leopold
- Otolaryngology, University of Vermont Medical Center, Burlington, Vermont, USA
| | - Joshua M Levy
- Otolaryngology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Michael J Marmura
- Neurology Thomas Jefferson University School of Medicine, Philadelphia, Pennsylvania, USA
| | - Lisha Mclelland
- Otolaryngology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Takaki Miwa
- Otolaryngology, Kanazawa Medical University, Ishikawa, Japan
| | - Paul J Moberg
- Psychiatry, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | | | - Sagar U Nigwekar
- Division of Nephrology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Erin K O'Brien
- Otolaryngology, Mayo Clinic Rochester, Rochester, Minnesota, USA
| | - Teodor G Paunescu
- Division of Nephrology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | | | - Carl Philpott
- Otolaryngology, University of East Anglia, Norwich, UK
| | - Jayant M Pinto
- Otolaryngology, University of Chicago, Chicago, Illinois, USA
| | - Evan R Reiter
- Otolaryngology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, USA
| | - David R Roalf
- Psychiatry, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Nicholas R Rowan
- Otolaryngology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Rodney J Schlosser
- Otolaryngology, Medical University of South Carolina, Mt Pleasant, South Carolina, USA
| | - James Schwob
- Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Allen M Seiden
- Otolaryngology, University of Cincinnati School of Medicine, Cincinnati, Ohio, USA
| | - Timothy L Smith
- Otolaryngology, Oregon Health and Sciences University, Portland, Oregon, USA
| | - Zachary M Soler
- Otolaryngology, Medical University of South Carolina, Mt Pleasant, South Carolina, USA
| | - Leigh Sowerby
- Otolaryngology, University of Western Ontario, London, Ontario, Canada
| | - Bruce K Tan
- Otolaryngology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Andrew Thamboo
- Otolaryngology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Bozena Wrobel
- Otolaryngology, Keck School of Medicine, USC, Los Angeles, California, USA
| | - Carol H Yan
- Otolaryngology, School of Medicine, UCSD, La Jolla, California, USA
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Hunter J, Arentz S, Goldenberg J, Yang G, Beardsley J, Myers SP, Mertz D, Leeder S. Zinc for the prevention or treatment of acute viral respiratory tract infections in adults: a rapid systematic review and meta-analysis of randomised controlled trials. BMJ Open 2021; 11:e047474. [PMID: 34728441 PMCID: PMC8578211 DOI: 10.1136/bmjopen-2020-047474] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE To evaluate the benefits and risks of zinc formulations compared with controls for prevention or treatment of acute viral respiratory tract infections (RTIs) in adults. METHOD Seventeen English and Chinese databases were searched in April/May 2020 for randomised controlled trials (RCTs), and from April/May 2020 to August 2020 for SARS-CoV-2 RCTs. Cochrane rapid review methods were applied. Quality appraisals used the Risk of Bias 2.0 and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. RESULTS Twenty-eight RCTs with 5446 participants were identified. None were specific to SARS-CoV-2. Compared with placebo, oral or intranasal zinc prevented 5 RTIs per 100 person-months (95% CI 1 to 8, numbers needed to treat (NNT)=20, moderate-certainty/quality). Sublingual zinc did not prevent clinical colds following human rhinovirus inoculations (relative risk, RR 0.96, 95% CI 0.77 to 1.21, moderate-certainty/quality). On average, symptoms resolved 2 days earlier with sublingual or intranasal zinc compared with placebo (95% CI 0.61 to 3.50, very low-certainty/quality) and 19 more adults per 100 were likely to remain symptomatic on day 7 without zinc (95% CI 2 to 38, NNT=5, low-certainty/quality). There were clinically significant reductions in day 3 symptom severity scores (mean difference, MD -1.20 points, 95% CI -0.66 to -1.74, low-certainty/quality), but not average daily symptom severity scores (standardised MD -0.15, 95% CI -0.43 to 0.13, low-certainty/quality). Non-serious adverse events (AEs) (eg, nausea, mouth/nasal irritation) were higher (RR 1.41, 95% CI 1.17 to 1.69, NNHarm=7, moderate-certainty/quality). Compared with active controls, there were no differences in illness duration or AEs (low-certainty/quality). No serious AEs were reported in the 25 RCTs that monitored them (low-certainty/quality). CONCLUSIONS In adult populations unlikely to be zinc deficient, there was some evidence suggesting zinc might prevent RTIs symptoms and shorten duration. Non-serious AEs may limit tolerability for some. The comparative efficacy/effectiveness of different zinc formulations and doses were unclear. The GRADE-certainty/quality of the evidence was limited by a high risk of bias, small sample sizes and/or heterogeneity. Further research, including SARS-CoV-2 clinical trials is warranted. PROSPERO REGISTRATION NUMBER CRD42020182044.
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Affiliation(s)
- Jennifer Hunter
- NICM Health Research Institute, Western Sydney University, Penrith, New South Wales, Australia
| | - Susan Arentz
- NICM Health Research Institute, Western Sydney University, Penrith, New South Wales, Australia
| | - Joshua Goldenberg
- Helfgott Research Institute, National University of Natural Medicine, Portland, Oregon, USA
| | - Guoyan Yang
- NICM Health Research Institute, Western Sydney University, Penrith, New South Wales, Australia
| | | | - Stephen P Myers
- NICM Health Research Institute, Western Sydney University, Penrith, New South Wales, Australia
- National Centre for Naturopathic Medicine, Southern Cross University, Lismore, New South Wales, Australia
| | - Dominik Mertz
- Division of Infectious Diseases, Department of Medicine, Health Sciences, McMaster University, Hamilton, Ontario, Canada
| | - Stephen Leeder
- The Menzies Centre for Health Policy, The University of Sydney, Sydney, New South Wales, Australia
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5
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Rahimzadeh MR, Rahimzadeh MR, Kazemi S, Moghadamnia AA. Zinc Poisoning - Symptoms, Causes, Treatments. Mini Rev Med Chem 2021; 20:1489-1498. [PMID: 32286942 DOI: 10.2174/1389557520666200414161944] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 11/14/2019] [Accepted: 01/02/2020] [Indexed: 01/19/2023]
Abstract
Zinc poisoning has been reported from many parts of the world. It is one of the global health problems that affect many organs, if exposed by inhalation of zinc vapors or by consumption of contaminated food and water. Long term exposure to zinc compounds from different sources such as air, water, soil, and food, lead to toxic effects on body systems, especially digestive, respiratory, and nerve systems, and also causes cancer. Zinc levels can be determined in blood, urine, hair, and nails. Patients with zinc toxicity need chelating agents, other pharmacological treatment, protective lung ventilation, extracorporeal membrane oxygenation (ECMO), and supportive care.
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Affiliation(s)
- Mehrdad Rafati Rahimzadeh
- Mobility Impairment Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
| | | | - Sohrab Kazemi
- Cellular and Molecular Biology Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
| | - Ali Akbar Moghadamnia
- Cellular and Molecular Biology Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
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Abstract
A wide variety of symptoms is associated with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection, and these symptoms can overlap with other conditions and diseases. Knowing the distribution of symptoms across diseases and individuals can support clinical actions on timelines shorter than those for drug and vaccine development. Here, we focus on zinc deficiency symptoms, symptom overlap with other conditions, as well as zinc effects on immune health and mechanistic zinc deficiency risk groups. There are well-studied beneficial effects of zinc on the immune system including a decreased susceptibility to and improved clinical outcomes for infectious pathogens including multiple viruses. Zinc is also an anti-inflammatory and anti-oxidative stress agent, relevant to some severe Coronavirus Disease 2019 (COVID-19) symptoms. Unfortunately, zinc deficiency is common worldwide and not exclusive to the developing world. Lifestyle choices and preexisting conditions alone can result in zinc deficiency, and we compile zinc risk groups based on a review of the literature. It is also important to distinguish chronic zinc deficiency from deficiency acquired upon viral infection and immune response and their different supplementation strategies. Zinc is being considered as prophylactic or adjunct therapy for COVID-19, with 12 clinical trials underway, highlighting the relevance of this trace element for global pandemics. Using the example of zinc, we show that there is a critical need for a deeper understanding of essential trace elements in human health, and the resulting deficiency symptoms and their overlap with other conditions. This knowledge will directly support human immune health for decreasing susceptibility, shortening illness duration, and preventing progression to severe cases in the current and future pandemics.
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Affiliation(s)
- Marcin P. Joachimiak
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States of America
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7
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Baraibar AM, Hernández-Guijo JM. Micromolar concentrations of Zn 2+ depress cellular excitability through a blockade of calcium current in rat adrenal slices. Toxicology 2020; 444:152543. [PMID: 32858065 DOI: 10.1016/j.tox.2020.152543] [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: 05/06/2020] [Revised: 07/08/2020] [Accepted: 07/25/2020] [Indexed: 11/30/2022]
Abstract
The present work, using chromaffin cells in rat adrenal slices (RCCs), aims to describe what type of ionic current alterations induced by zinc underlies their effects reported on synaptic transmission. Thus, Zn2+ blocked calcium channels of RCCs in a time- and concentration-dependent manner with an IC50 of 391 μM. This blockade was partially reversed upon washout and was greater at more depolarizing holding potentials (i.e. 32 ± 5% at -110 mV, and 43 ± 6% at -50 mV, after 5 min perfusion). In ω-toxins-sensitive calcium channels (N-, P- and Q-types), Zn2+caused a lower blockade of ICa, 33.3%, than in ω-toxins-resistant ones (L-type, 55.3%; and R-type, 90%). This compound inhibited calcium current at all test potentials and shows a shift of the I-V curve to more depolarized values of about 10 mV. The sodium current was not blocked by acute application of high Zn2+concentrations. Voltage-dependent potassium current was marginally affected by high Zn2+ concentrations showing no concentration-dependence. Nevertheless, calcium- and voltage-dependent potassium current was drastically depressed in a dose-dependent manner, with an IC50 of 453 μM. This blockade was related to the prevention of Ca2+ influx through voltage-dependent calcium channels coupled to BK channels. Under current-clamp conditions, RCCs exhibit a resting potential of -50.7 mV, firing spontaneous APs (1-2 spikes/s) generated by the opening of Na+ and Ca2+-channels, and terminated by the activation of voltage and Ca2+-activated K+-channels (BK). We found that the blockade of these ionic currents by Zn2+ led to a drastic alteration of cellular excitability with a depolarization of the membrane potential, the slowdown and broadening of the APs and the severe reduction of the after hyperpolarization (AHP) which led to a decrease in the APs firing frequency. Taken together, these results point to a neurotoxic action evoked by zinc that is associated with changes to cellular excitability by blocking the ionic currents responsible for both the neurotransmitter release and the action potentials firing.
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Affiliation(s)
- Andrés M Baraibar
- Department of Neuroscience, University of Minnesota, 4-260 Wallin Medical Biosciences Building, 2101 6th Street SE, Minneapolis, MN, 55455, USA
| | - Jesús M Hernández-Guijo
- Department of Pharmacology and Therapeutic, Univ. Autónoma de Madrid, Av. Arzobispo Morcillo 4, 28029, Madrid, Spain; Instituto Teófilo Hernando, Facultad de Medicina, Univ. Autónoma de Madrid, Av. Arzobispo Morcillo 4, 28029, Madrid, Spain; Instituto Ramón y Cajal de Investigación Sanitaria, IRYCIS, Hospital Ramón y Cajal, Ctra. de Colmenar Viejo, Km. 9,100, 28029, Madrid, Spain.
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8
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Rosenbloom M, Barclay T, Johnsen J, Erickson L, Svitak A, Pyle M, Frey W, Hanson LR. Double-Blind Placebo-Controlled Pilot Investigation of the Safety of a Single Dose of Rapid-Acting Intranasal Insulin in Down Syndrome. Drugs R D 2020; 20:11-15. [PMID: 32077057 PMCID: PMC7067723 DOI: 10.1007/s40268-020-00296-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Background Individuals with Down syndrome are likely to develop clinical and neuropathological brain changes resembling Alzheimer’s disease dementia by the ages of 35–40 years. Intranasal insulin is a potential treatment for neurodegenerative disease that has been shown to reduce amyloid plaque burden and improve verbal memory performance in normal as well as memory-impaired adults. Investigations have shown that rapid-acting insulins may result in superior cognitive benefits compared with regular insulin. Objectives The primary objective of this study was to measure the safety and feasibility of intranasal rapid-acting glulisine in subjects with Down syndrome. Secondarily, we estimated the effects of intranasal glulisine on cognition and memory in Down syndrome. Methods A single-center, single-dose, randomized, double-blind, placebo-controlled, cross-over pilot study was performed to test the safety of intranasal glulisine vs placebo in 12 subjects with Down syndrome aged ≥ 35 years. Intranasal administration utilized the Impel NeuroPharma I109 Precision Olfactory Delivery (POD®) device. The primary outcomes were the occurrence of any or related adverse and serious adverse events. Secondary post-treatment cognitive outcome measures included performance on the Fuld Object-Memory Evaluation and Rivermead Behavioral Memory Test. Results Intranasal glulisine was safe and well tolerated in the Down syndrome population. No adverse or serious adverse events were observed. Conclusions Further investigations are necessary to better evaluate the potential cognitive-enhancing role of intranasal insulin in the Down syndrome population. ClinicalTrials.gov ID NCT02432716. Electronic supplementary material The online version of this article (10.1007/s40268-020-00296-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Michael Rosenbloom
- HealthPartners Center for Memory and Aging, 295 Phalen Boulevard, Saint Paul, MN, 55130, USA.
- HealthPartners Institute, Bloomington, MN, USA.
| | - Terry Barclay
- HealthPartners Center for Memory and Aging, 295 Phalen Boulevard, Saint Paul, MN, 55130, USA
| | - Justin Johnsen
- HealthPartners Center for Memory and Aging, 295 Phalen Boulevard, Saint Paul, MN, 55130, USA
| | | | - Aleta Svitak
- HealthPartners Center for Memory and Aging, 295 Phalen Boulevard, Saint Paul, MN, 55130, USA
| | - Maria Pyle
- HealthPartners Center for Memory and Aging, 295 Phalen Boulevard, Saint Paul, MN, 55130, USA
| | - William Frey
- HealthPartners Center for Memory and Aging, 295 Phalen Boulevard, Saint Paul, MN, 55130, USA
- HealthPartners Institute, Bloomington, MN, USA
| | - Leah R Hanson
- HealthPartners Center for Memory and Aging, 295 Phalen Boulevard, Saint Paul, MN, 55130, USA
- HealthPartners Institute, Bloomington, MN, USA
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9
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Arnold C. Sensory Overload? Air Pollution and Impaired Olfaction. ENVIRONMENTAL HEALTH PERSPECTIVES 2019; 127:62001. [PMID: 31190551 PMCID: PMC6791585 DOI: 10.1289/ehp3621] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
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10
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Abstract
This review addresses the adverse influences of neurotoxic exposures on the ability to smell and taste. These chemical senses largely determine the flavor of foods and beverages, impact food intake, and ultimately nutrition, and provide a warning for spoiled or poisonous food, leaking natural gas, smoke, airborne pollutants, and other hazards. Hence, toxicants that damage these senses have a significant impact on everyday function. As noted in detail, a large number of toxicants encountered in urban and industrial air pollution, including smoke, solvents, metals, and particulate matter can alter the ability to smell. Their influence on taste, i.e., sweet, sour, bitter, salty, and savory (umami) sensations, is not well documented. Given the rather direct exposure of olfactory receptors to the outside environment, olfaction is particularly vulnerable to damage from toxicants. Some toxicants, such as nanoparticles, have the potential to damage not only the olfactory receptor cells, but also the central nervous system structures by their entrance into the brain through the olfactory mucosa.
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Affiliation(s)
- Mary Beth Genter
- Department of Environmental Health, University of Cincinnati, Cincinnati, OH, United States
| | - Richard L Doty
- Smell and Taste Center and Department of Otorhinolaryngology: Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States.
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Werner S, Nies E. Olfactory dysfunction revisited: a reappraisal of work-related olfactory dysfunction caused by chemicals. J Occup Med Toxicol 2018; 13:28. [PMID: 30202422 PMCID: PMC6124006 DOI: 10.1186/s12995-018-0209-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 07/30/2018] [Indexed: 11/10/2022] Open
Abstract
Occupational exposure to numerous individual chemicals has been associated with olfactory dysfunction, mainly in individual case descriptions. Comprehensive epidemiological investigations into the olfactotoxic effect of working substances show that the human sense of smell may be impaired by exposure to metal compounds involving cadmium, chromium and nickel, and to formaldehyde. This conclusion is supported by the results of animal experiments. The level of evidence for a relationship between olfactory dysfunction and workplace exposure to other substances is relatively weak.
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Affiliation(s)
- Sabine Werner
- Institute for Occupational Safety and Health of the German Social Accident Insurance, Unit Toxicology of Industrial Chemicals, Alte Heerstrasse 111, 53757 Sankt Augustin, Germany
| | - Eberhard Nies
- Institute for Occupational Safety and Health of the German Social Accident Insurance, Unit Toxicology of Industrial Chemicals, Alte Heerstrasse 111, 53757 Sankt Augustin, Germany
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12
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Vann KT, Xiong ZG. Acid-sensing ion channel 1 contributes to normal olfactory function. Behav Brain Res 2018; 337:246-251. [PMID: 28912013 PMCID: PMC5645255 DOI: 10.1016/j.bbr.2017.09.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 09/01/2017] [Accepted: 09/06/2017] [Indexed: 11/21/2022]
Abstract
Acid-sensing ion channels (ASICs) are cation channels activated by protons. ASIC1a, a primary ASIC subunit in the brain, was recently characterized in the olfactory bulb. The present study tested the hypothesis that ASIC1a is essential for normal olfactory function. Olfactory behavior of wild-type (WT) and ASIC1-/- mice was evaluated by using three standard olfactory tests: (1) the buried food test, (2) the olfactory habituation test, and (3) the olfactory preference test. In buried food test, ASIC1-/- mice had significantly longer latency to uncover buried food than WT mice. In olfactory habituation test, ASIC1-/- mice had increased sniffing time with acidic odorants. In olfactory preference test, ASIC1-/- mice did not exhibit normal avoidance behavior for 2, 5- dihydro-2, 4, 5-trimethylthiazoline (TMT). Consistent with ASIC1 knockout, ASIC1 inhibition by nasal administration of PcTX1 increased the latency for WT mice to uncover the buried food. Together, these findings suggest a key role for ASIC1a in normal olfactory function.
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Affiliation(s)
- Kiara T Vann
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, Georgia.
| | - Zhi-Gang Xiong
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, Georgia.
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13
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14
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Gardner B, Dieriks BV, Cameron S, Mendis LHS, Turner C, Faull RLM, Curtis MA. Metal concentrations and distributions in the human olfactory bulb in Parkinson's disease. Sci Rep 2017; 7:10454. [PMID: 28874699 PMCID: PMC5585381 DOI: 10.1038/s41598-017-10659-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 08/14/2017] [Indexed: 01/10/2023] Open
Abstract
In Parkinson's disease (PD), the olfactory bulb is typically the first region in the body to accumulate alpha-synuclein aggregates. This pathology is linked to decreased olfactory ability, which becomes apparent before any motor symptoms occur, and may be due to a local metal imbalance. Metal concentrations were investigated in post-mortem olfactory bulbs and tracts from 17 human subjects. Iron (p < 0.05) and sodium (p < 0.01) concentrations were elevated in the PD olfactory bulb. Combining laser ablation inductively coupled plasma mass spectrometry and immunohistochemistry, iron and copper were evident at very low levels in regions of alpha-synuclein aggregation. Zinc was high in these regions, and free zinc was detected in Lewy bodies, mitochondria, and lipofuscin of cells in the anterior olfactory nucleus. Increased iron and sodium in the human PD olfactory bulb may relate to the loss of olfactory function. In contrast, colocalization of free zinc and alpha-synuclein in the anterior olfactory nucleus implicate zinc in PD pathogenesis.
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Affiliation(s)
- Bronwen Gardner
- Centre for Brain Research and Department of Anatomy with Medical Imaging, University of Auckland, Auckland, New Zealand
| | - Birger V Dieriks
- Centre for Brain Research and Department of Anatomy with Medical Imaging, University of Auckland, Auckland, New Zealand
| | - Steve Cameron
- Waikato Mass Spectrometry Facility, University of Waikato, Hamilton, New Zealand
| | - Lakshini H S Mendis
- Centre for Brain Research and Department of Anatomy with Medical Imaging, University of Auckland, Auckland, New Zealand
| | - Clinton Turner
- Centre for Brain Research and Department of Anatomy with Medical Imaging, University of Auckland, Auckland, New Zealand
- Department of Anatomical Pathology, LabPlus, Auckland City Hospital, Auckland, New Zealand
| | - Richard L M Faull
- Centre for Brain Research and Department of Anatomy with Medical Imaging, University of Auckland, Auckland, New Zealand
| | - Maurice A Curtis
- Centre for Brain Research and Department of Anatomy with Medical Imaging, University of Auckland, Auckland, New Zealand.
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15
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Block E, Batista VS, Matsunami H, Zhuang H, Ahmed L. The role of metals in mammalian olfaction of low molecular weight organosulfur compounds. Nat Prod Rep 2017; 34:529-557. [PMID: 28471462 PMCID: PMC5542778 DOI: 10.1039/c7np00016b] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Covering: up to the end of 2017While suggestions concerning the possible role of metals in olfaction and taste date back 50 years, only recently has it been possible to confirm these proposals with experiments involving individual olfactory receptors (ORs). A detailed discussion of recent experimental results demonstrating the key role of metals in enhancing the response of human and other vertebrate ORs to specific odorants is presented against the backdrop of our knowledge of how the sense of smell functions both at the molecular and whole animal levels. This review emphasizes the role of metals in the detection of low molecular weight thiols, sulfides, and other organosulfur compounds, including those found in strong-smelling animal excretions and plant volatiles, and those used in gas odorization. Alternative theories of olfaction are described, with evidence favoring the modified "shape" theory. The use of quantum mechanical/molecular modeling (QM/MM), site-directed mutagenesis and saturation-transfer-difference (STD) NMR is discussed, providing support for biological studies of mouse and human receptors, MOR244-3 and OR OR2T11, respectively. Copper is bound at the active site of MOR244-3 by cysteine and histidine, while cysteine, histidine and methionine are involved with OR2T11. The binding pockets of these two receptors are found in different locations in the three-dimensional seven transmembrane models. Another recently deorphaned human olfactory receptor, OR2M3, highly selective for a thiol from onions, and a broadly-tuned thiol receptor, OR1A1, are also discussed. Other topics covered include the effects of nanoparticles and heavy metal toxicants on vertebrate and fish ORs, intranasal zinc products and the loss of smell (anosmia).
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Affiliation(s)
- Eric Block
- Department of Chemistry, University at Albany, State University of New York, Albany, New York 12222, USA.
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16
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Hsieh H, Horwath MC, Genter MB. Zinc gluconate toxicity in wild-type vs. MT1/2-deficient mice. Neurotoxicology 2016; 58:130-136. [PMID: 27979773 DOI: 10.1016/j.neuro.2016.12.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 12/08/2016] [Accepted: 12/09/2016] [Indexed: 10/20/2022]
Abstract
Previous studies have suggested that oral zinc supplementation can help reduce the duration of the common cold; however, the use of intranasal (IN) zinc is strongly associated with anosmia, or the loss of the sense of smell, in humans. Prior studies from this lab showed that upregulation of metallothioneins (MT) is a rapid and robust response to zinc gluconate (ZG). Therefore, we assessed the role of MT in the recovery of nasal epithelial damage resulting from IN zinc administration. The main studies in this investigation used a high dose of ZG (170mM) to ensure ablation of the olfactory mucosa, so that the progression of histological and functional recovery could be assessed. In vivo studies using wild-type, MT1/2 knockout mice (MT KO), and heterozygotes administered ZG by IN instillation showed profound loss of the olfactory mucosa in the nasal cavity. Recovery was monitored, and a lower percentage of the MT KO mice were able to smell 28 d after treatment; however, no significant difference was observed in the rate of cell proliferation in the basal layer of the olfactory epithelium between MT KO and wild-type mice. A lower concentration of ZG (33mM), equivalent to that found in homeopathic IN ZG preparations, also caused olfactory epithelial toxicity in mice. These studies suggest that the use of zinc in drug formulations intended for IN administration in humans must be carefully evaluated for their potential to cause olfactory functional deficits.
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Affiliation(s)
- Heidi Hsieh
- Department of Environmental Health, University of Cincinnati, Cincinnati, OH 45267-0056, United States
| | - Michael C Horwath
- Department of Internal Medicine, University of Cincinnati, Cincinnati, OH 45267-0557, United States; Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, United States
| | - Mary Beth Genter
- Department of Environmental Health, University of Cincinnati, Cincinnati, OH 45267-0056, United States.
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Exposure to Zinc Sulfate Results in Differential Effects on Olfactory Sensory Neuron Subtypes in Adult Zebrafish. Int J Mol Sci 2016; 17:ijms17091445. [PMID: 27589738 PMCID: PMC5037724 DOI: 10.3390/ijms17091445] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 08/23/2016] [Accepted: 08/25/2016] [Indexed: 12/20/2022] Open
Abstract
Zinc sulfate is a known olfactory toxicant, although its specific effects on the olfactory epithelium of zebrafish are unknown. Olfactory organs of adult zebrafish were exposed to zinc sulfate and, after 2, 3, 5, 7, 10 or 14 days, fish were processed for histological, immunohistochemical, ultrastructural, and behavioral analyses. Severe morphological disruption of the olfactory organ was observed two days following zinc sulfate exposure, including fusion of lamellae, epithelial inflammation, and significant loss of anti-calretinin labeling. Scanning electron microscopy revealed the apical surface of the sensory region was absent of ciliated structures, but microvilli were still present. Behavioral analysis showed significant loss of the ability to perceive bile salts and some fish also had no response to amino acids. Over the next several days, olfactory organ morphology, epithelial structure, and anti-calretinin labeling returned to control-like conditions, although the ability to perceive bile salts remained lost until day 14. Thus, exposure to zinc sulfate results in rapid degeneration of the olfactory organ, followed by restoration of morphology and function within two weeks. Zinc sulfate appears to have a greater effect on ciliated olfactory sensory neurons than on microvillous olfactory sensory neurons, suggesting differential effects on sensory neuron subtypes.
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18
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Hsieh H, Vignesh KS, Deepe GS, Choubey D, Shertzer HG, Genter MB. Mechanistic studies of the toxicity of zinc gluconate in the olfactory neuronal cell line Odora. Toxicol In Vitro 2016; 35:24-30. [PMID: 27179668 DOI: 10.1016/j.tiv.2016.05.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 05/06/2016] [Accepted: 05/09/2016] [Indexed: 11/15/2022]
Abstract
Zinc is both an essential and potentially toxic metal. It is widely believed that oral zinc supplementation can reduce the effects of the common cold; however, there is strong clinical evidence that intranasal (IN) zinc gluconate (ZG) gel treatment for this purpose causes anosmia, or the loss of the sense of smell, in humans. Using the rat olfactory neuron cell line, Odora, we investigated the molecular mechanism by which zinc exposure exerts its toxic effects on olfactory neurons. Following treatment of Odora cells with 100 and 200μM ZG for 0-24h, RNA-seq and in silico analyses revealed up-regulation of pathways associated with zinc metal response, oxidative stress, and ATP production. We observed that Odora cells recovered from zinc-induced oxidative stress, but ATP depletion persisted with longer exposure to ZG. ZG exposure increased levels of NLRP3 and IL-1β protein levels in a time-dependent manner, suggesting that zinc exposure may cause an inflammasome-mediated cell death, pyroptosis, in olfactory neurons.
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Affiliation(s)
- Heidi Hsieh
- Department of Environmental Health, University of Cincinnati, Cincinnati, OH 45267-0056, United States
| | | | - George S Deepe
- Department of Internal Medicine, University of Cincinnati, Cincinnati, OH 45267-0557, United States; Veterans Affairs Medical Center, Cincinnati, OH 45220, United States
| | - Divaker Choubey
- Department of Environmental Health, University of Cincinnati, Cincinnati, OH 45267-0056, United States
| | - Howard G Shertzer
- Department of Environmental Health, University of Cincinnati, Cincinnati, OH 45267-0056, United States
| | - Mary Beth Genter
- Department of Environmental Health, University of Cincinnati, Cincinnati, OH 45267-0056, United States.
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19
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Hamidovic A. Position on zinc delivery to olfactory nerves in intranasal insulin phase I-III clinical trials. Contemp Clin Trials 2015; 45:277-280. [PMID: 26386292 DOI: 10.1016/j.cct.2015.08.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 08/18/2015] [Accepted: 08/23/2015] [Indexed: 11/29/2022]
Abstract
Zinc in pancreatic insulin is essential for processing and action of the peptide, while in commercial preparations zinc promotes hexameric structure and prevents aggregate formation. In 2002, for the first time, insulin was delivered to humans intranasally with resulting cerebrospinal fluid insulin increases, but steady peripheral insulin levels. The novel method of increasing brain insulin levels without changes in the periphery resulted in an expansion of brain insulin research in clinical trials. As pre-clinical research has shown that brain insulin modulates a number functions, including food cravings and eating behavior, learning and memory functions, stress and mood regulation; realization of beneficial effects of insulin in modulating these functions in clinical populations became a possibility with the new direct-to-brain insulin delivery methodology. However, zinc, being integral to insulin structure and function, is neurotoxic, and has resulted in adverse effects to human health. In the last century, intranasal zinc was given preventively during the time of polio outbreak, and in the 21st century intranasal zinc was widely used over the counter to prevent common cold. In both cases, patients experienced partial or complete loss of smell. This paper is the first one to analyze zinc salts and concentrations of those two epidemiological adversities and directly compare formulations distributed to the public with animal toxicity data. The information gained from animal and epidemiological data provides a foundation for the formation of opinion given in this paper regarding safety of intranasal zinc in emerging clinical trials with intranasal insulin.
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Affiliation(s)
- A Hamidovic
- College of Pharmacy, University of New Mexico, MSC09 5360, 1 University of New Mexico, Albuquerque, NM 87131-0001, United States.
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20
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Abstract
Nearly all obstetricians routinely prescribe prenatal vitamins to their pregnant patients at the time of the first prenatal visit. Many times, patients' understanding of the health benefits of prenatal vitamins differs substantially from that of the prescribing physician. The following is a review of the most common ingredients found in prenatal vitamins and their purported health benefits.
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Hemilä H, Chalker E. The effectiveness of high dose zinc acetate lozenges on various common cold symptoms: a meta-analysis. BMC FAMILY PRACTICE 2015; 16:24. [PMID: 25888289 PMCID: PMC4359576 DOI: 10.1186/s12875-015-0237-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 01/29/2015] [Indexed: 11/23/2022]
Abstract
BACKGROUND A previous meta-analysis found that high dose zinc acetate lozenges reduced the duration of common colds by 42%, whereas low zinc doses had no effect. Lozenges are dissolved in the pharyngeal region, thus there might be some difference in the effect of zinc lozenges on the duration of respiratory symptoms in the pharyngeal region compared with the nasal region. The objective of this study was to determine whether zinc acetate lozenges have different effects on the duration of common cold symptoms originating from different anatomical regions. METHODS We analyzed three randomized trials on zinc acetate lozenges for the common cold administering zinc in doses of 80-92 mg/day. All three trials reported the effect of zinc on seven respiratory symptoms, and three systemic symptoms. We pooled the effects of zinc lozenges for each symptom and calculated point estimates and 95% confidence intervals (95% CI). RESULTS Zinc acetate lozenges shortened the duration of nasal discharge by 34% (95% CI: 17% to 51%), nasal congestion by 37% (15% to 58%), sneezing by 22% (-1% to 45%), scratchy throat by 33% (8% to 59%), sore throat by 18% (-10% to 46%), hoarseness by 43% (3% to 83%), and cough by 46% (28% to 64%). Zinc lozenges shortened the duration of muscle ache by 54% (18% to 89%), but there was no difference in the duration of headache and fever. CONCLUSIONS The effect of zinc acetate lozenges on cold symptoms may be associated with the local availability of zinc from the lozenges, with the levels being highest in the pharyngeal region. However our findings indicate that the effects of zinc ions are not limited to the pharyngeal region. There is no indication that the effect of zinc lozenges on nasal symptoms is less than the effect on the symptoms of the pharyngeal region, which is more exposed to released zinc ions. Given that the adverse effects of zinc in the three trials were minor, zinc acetate lozenges releasing zinc ions at doses of about 80 mg/day may be a useful treatment for the common cold, started within 24 hours, for a time period of less than two weeks.
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Affiliation(s)
- Harri Hemilä
- Department of Public Health, POB 41, University of Helsinki, Mannerheimintie 172, FIN-00014, Helsinki, Finland.
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22
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A single-dose pilot trial of intranasal rapid-acting insulin in apolipoprotein E4 carriers with mild-moderate Alzheimer's disease. CNS Drugs 2014; 28:1185-9. [PMID: 25373630 DOI: 10.1007/s40263-014-0214-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
INTRODUCTION Intranasal (IN) insulin acutely improves verbal memory in mild cognitive impairment (MCI)/Alzheimer's disease (AD), but its therapeutic effects may be attenuated in apolipoprotein E4 (ApoE4) carriers. Furthermore, rapid-acting (RA) insulins may have superior therapeutic effects compared with regular insulin types. OBJECTIVES To measure the safety and efficacy of intranasally delivered RA glulisine in ApoE4 carriers with mild-moderate AD. METHODS We performed a double-blinded, randomized, cross-over study of RA insulin glulisine in nine mild-moderate AD subjects to better understand the relationship between RA insulin, ApoE4 carrier status and memory performance. RESULTS IN glulisine was well tolerated but failed to have an acute impact on cognition in ApoE4 carriers with AD. Serum insulin levels acutely dropped following treatment, but peripheral glucose levels remained unchanged. CONCLUSION Larger clinical trials of longer duration are necessary to better understand the relationships between RA insulin, ApoE4 carrier status and cognitive performance in AD.
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23
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Hsieh H, Amlal H, Genter MB. Evaluation of the toxicity of zinc in the rat olfactory neuronal cell line, Odora. Hum Exp Toxicol 2014; 34:308-14. [PMID: 24980442 DOI: 10.1177/0960327114538985] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Zinc (Zn) has long been touted as a panacea for common cold. Recently, there has been some controversy over whether an intranasal (IN) zinc gluconate gel, purported to fight colds, causes anosmia, or loss of the sense of smell, in humans. Previous evidence has shown that IN zinc sulfate (ZnSO4) solutions can cause anosmia in humans as well as significant damage to the olfactory epithelium in rodents. Using an in vitro olfactory neuron model (the rat Odora cell line), we tested the hypothesis that Zn toxicity was caused by inhibition of the hydrogen voltage-gated channel 1(HVCN1), leading to acidosis and apoptotic cell death. Following studies to characterize the toxicity of zinc gluconate and ZnSO4, Odora cells were grown on coverslips and loaded with 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein acetoxymethyl ester to measure intracellular pH in the presence and absence of Zn salts. While we found that HVCN1 is not functional in Odora cells, we found that olfactory neurons in vitro maintain their intracellular pH through a sodium/proton exchanger, specifically the sodium proton antiporter 1. ZnSO4, at nontoxic levels, had no impact on intracellular pH after acute exposure or after 24 h of incubation with the cells. In conclusion, Zn toxicity is not mediated through an acidification of intracellular pH in olfactory neurons in vitro.
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Affiliation(s)
- H Hsieh
- Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - H Amlal
- Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - M B Genter
- Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, OH, USA
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24
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Sniffing out pharmacology: interactions of drugs with human olfaction. Trends Pharmacol Sci 2012; 33:193-9. [PMID: 22361590 DOI: 10.1016/j.tips.2012.01.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 01/22/2012] [Accepted: 01/24/2012] [Indexed: 11/23/2022]
Abstract
Advances in the understanding of the sense of smell have increased awareness of the role of olfaction in human life. Odors are perceived via specific G protein-coupled receptors (GPCRs) with cAMP as the second messenger. Drugs that interact with this signaling cascade, such as opioids, cannabinoids and sildenafil, are known to reduce olfactory function. Drugs that are active in the central nervous system (CNS) may also hinder the complex processing of olfactory information to distinguish, via pattern recognition, thousands of odors from the signals of only ∼400 distinct olfactory receptors. Many other interactions with drug targets expressed at the olfactory bulb are also likely to occur. However, olfactory drug effects have rarely been explored in controlled studies. In the current activities of drug development and re-purposing, olfaction could become highly important because it can impact significantly upon the enjoyment of food. With an established molecular basis and using available tools, the assessment of olfaction in drug development and approval is advised.
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Lim JH, Davis GE, Rue TC, Storm DR. Human sinonasal explant system for testing cytotoxicity of intranasal agents. Int Forum Allergy Rhinol 2011; 2:63-8. [PMID: 22170775 DOI: 10.1002/alr.20110] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Revised: 09/13/2011] [Accepted: 10/21/2011] [Indexed: 11/09/2022]
Abstract
BACKGROUND Intranasal agents play a critical role in the management of sinonasal disorders. There are ongoing efforts to develop new intranasal medications to combat sinonasal disease. Some intranasal agents, however, can have cytotoxic effects on human sinonasal tissue. In order to facilitate safe drug discovery, we developed a simple and reliable in vitro screening assay using human sinonasal explants to measure the cytotoxic profiles of intranasal agents. METHODS We obtained sinonasal tissues from several regions of the nasal cavity from 12 patients undergoing endoscopic sinonasal surgery. These tissues were cultured on polytetrafluoroethylene membrane in serum-free growth medium. We determined the biochemical properties of these explants by measuring extracellular lactate dehydrogenase (LDH) levels and performing histological analyses over a period of 1 to 2 weeks. We then examined the cytotoxic profiles of 13 intranasal agents by measuring extracellular LDH levels using the human sinonasal explant system. RESULTS Sinonasal explants exhibited a rapid reduction in extracellular LDH levels indicating stabilization in the culture environment within 2 days. Histological analysis showed maintenance of good cellular architecture for up to 2 weeks. The explants displayed intact epithelium and expressed βIII-tubulin and Ki-67. Of the 13 tested intranasal agents, 1% zinc sulfate (ZnSO(4) ), 5% ZnSO(4) , and Zicam application were cytotoxic. CONCLUSION Based on the unique biochemical properties of the human nasal explant culture system, we developed a simple and reliable in vitro screening assay to determine the cytotoxic profiles of various intranasal agents by examining extracellular LDH levels and histopathology.
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Affiliation(s)
- Jae H Lim
- Department of Otolaryngology-Head and Neck Surgery, University of Washington, Seattle, WA 98195, USA.
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26
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Philpott CM, Gane S, McKiernan D. Nanomedicine in otorhinolaryngology: what does the future hold? Eur Arch Otorhinolaryngol 2010; 268:489-96. [DOI: 10.1007/s00405-010-1418-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Accepted: 10/25/2010] [Indexed: 11/30/2022]
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Schmalstieg FC, Goldman AS. The therapeutic test: an ancient malady in the 21st century. Ann Pharmacother 2010; 44:1471-7. [PMID: 20716691 DOI: 10.1345/aph.1p244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The response to treatment was the diagnostic mainstay in ancient times when diseases were poorly understood. Now that the bases of most diseases are known, appropriate diagnostic means are available. However, many physicians still rely on therapeutic tests to establish diagnoses. Since most illnesses are self-limited and because of the placebo effect, many physicians and patients attribute the improvement to the medication and believe that the correct diagnosis was made. However, inappropriate therapeutic tests often lead to diagnostic delays, rapid emergence of antibiotic-resistant bacterial pathogens, increased risks of adverse drug reactions, and unnecessary expenses. To reduce the frequency of unwarranted therapeutic tests, health-care professionals and educators must take steps to rectify the problem.
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Affiliation(s)
- Frank C Schmalstieg
- Division of Infectious Disease and Immunology, Department of Pediatrics, University of Texas Medical Branch, Galveston, TX, USA
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28
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Lim JH, Davis GE, Wang Z, Li V, Wu Y, Rue TC, Storm DR. Zicam-induced damage to mouse and human nasal tissue. PLoS One 2009; 4:e7647. [PMID: 19876403 PMCID: PMC2765727 DOI: 10.1371/journal.pone.0007647] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2009] [Accepted: 10/08/2009] [Indexed: 11/18/2022] Open
Abstract
Intranasal medications are used to treat various nasal disorders. However, their effects on olfaction remain unknown. Zicam (zinc gluconate; Matrixx Initiatives, Inc), a homeopathic substance marketed to alleviate cold symptoms, has been implicated in olfactory dysfunction. Here, we investigated Zicam and several common intranasal agents for their effects on olfactory function. Zicam was the only substance that showed significant cytotoxicity in both mouse and human nasal tissue. Specifically, Zicam-treated mice had disrupted sensitivity of olfactory sensory neurons to odorant stimulation and were unable to detect novel odorants in behavioral testing. These findings were long-term as no recovery of function was observed after two months. Finally, human nasal explants treated with Zicam displayed significantly elevated extracellular lactate dehydrogenase levels compared to saline-treated controls, suggesting severe necrosis that was confirmed on histology. Our results demonstrate that Zicam use could irreversibly damage mouse and human nasal tissue and may lead to significant smell dysfunction.
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Affiliation(s)
- Jae H. Lim
- Department of Otolaryngology-Head and Neck Surgery, University of Washington, Seattle, Washington, United States of America
| | - Greg E. Davis
- Department of Otolaryngology-Head and Neck Surgery, University of Washington, Seattle, Washington, United States of America
| | - Zhenshan Wang
- Department of Pharmacology, University of Washington, Seattle, Washington, United States of America
| | - Vicky Li
- Department of Pharmacology, University of Washington, Seattle, Washington, United States of America
| | - Yuping Wu
- Department of Pharmacology, University of Washington, Seattle, Washington, United States of America
| | - Tessa C. Rue
- Department of Biostatistics, University of Washington, Seattle, Washington, United States of America
| | - Daniel R. Storm
- Department of Pharmacology, University of Washington, Seattle, Washington, United States of America
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Caruso TJ, Prober CG, Gwaltney JM. Treatment of naturally acquired common colds with zinc: a structured review. Clin Infect Dis 2007; 45:569-74. [PMID: 17682990 DOI: 10.1086/520031] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2007] [Accepted: 05/01/2007] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND Over the past 20 years, the use of zinc as an over-the-counter alternative therapy for the common cold has vastly grown in popularity. Recent reports of potentially permanent anosmia caused by intranasal zinc therapy warrant careful analysis of the therapeutic effects of zinc. METHODS A search of the Medline database (including articles published during 1966-2006) for studies of zinc and the common cold produced 105 published reports. Fourteen were randomized, placebo-controlled studies that examined the effect of zinc lozenges, nasal sprays, or nasal gels on naturally acquired common colds. Eleven features of experimental design affecting signal quality, chance, bias, and blinding were used to evaluate the 14 placebo-controlled studies. These criteria were validated case definition, quantifiable hypothesis, sample size calculation, randomized assignment, double blinding, proof of blinding, measurement of compliance, measurement of dropout rate, analysis by intent to treat, description of methods of analysis, and measurements of probability. Equal weight was given to each criterion, because failure to meet any one could potentially invalidate the findings of a clinical trial. RESULTS Four studies met all 11 criteria. Three of these studies reported no therapeutic effect from zinc lozenge or nasal spray. One study reported positive results from zinc nasal gel. Of the remaining 10 studies, 6 reported a positive effect and 4 reported no effect. Intent-to-treat analysis was the most common criterion not met. CONCLUSIONS This structured review suggests that the therapeutic effectiveness of zinc lozenges has yet to be established. One well-designed study did report a positive effect of zinc nasal gel.
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Affiliation(s)
- Thomas J Caruso
- 1Stanford University School of Medicine, Stanford, California, USA
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Bibliography. Current world literature. Nose and paranasal sinuses. Curr Opin Otolaryngol Head Neck Surg 2007; 15:48-55. [PMID: 17211184 DOI: 10.1097/moo.0b013e32802e6d9b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Slotnick B, Sanguino A, Husband S, Marquino G, Silberberg A. Olfaction and olfactory epithelium in mice treated with zinc gluconate. Laryngoscope 2007; 117:743-9. [PMID: 17415147 DOI: 10.1097/mlg.0b013e318033006b] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE We assessed whether a nasal spray containing zinc gluconate (ZG) compromises the integrity of olfactory epithelium and olfactory function. METHODS Axonal transport of horseradish peroxidase from olfactory epithelium to the olfactory bulb was studied in 2- to 21-day survival mice given intranasal injections of 2, 8, or 50 microL of ZG (approximately 4, 15, and 94 times the equivalent recommended human dose). Other similarly treated mice were tested using precision olfactometry to detect and discriminate odors. RESULTS Anatomic changes were graded as a function of dose and survival time. Two microliter injections had no discernable effect. while the 50 microL volume produced substantial deafferentation of input to the olfactory bulb in short-survival cases. Nearly complete restitution of input occurred within 3 weeks. At each volume and survival time, zinc sulfate (ZS) had a greater effect. Behaviorally, 2 microL and 8 microL ZG-treated mice and those given multiple injections of 2 microL ZG performed as well as controls, whereas those given 50 microL were hyposmic but not anosmic. ZS-treated mice performed more poorly, and those injected with 50 microL were anosmic for the first 8 to 10 test days. CONCLUSIONS A massive dose of a ZG nasal spray did cause a transient disruption of the olfactory epithelium and compromised olfaction. More moderate volumes, even those far in excess of a recommended dose, were largely without effect on odor detection and discrimination tasks. These outcomes fail to support the claims from recent clinical case reports that use of a ZG-containing nasal spray can produce anosmia.
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Affiliation(s)
- Burton Slotnick
- Department of Psychology, University of South Florida, Tampa, Florida, USA.
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McNeill E, Ramakrishnan Y, Carrie S. Diagnosis and management of olfactory disorders: survey of UK-based consultants and literature review. The Journal of Laryngology & Otology 2007; 121:713-20. [PMID: 17359559 DOI: 10.1017/s0022215107006615] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/12/2006] [Indexed: 11/06/2022]
Abstract
AbstractBackground:The diagnosis and management of olfactory disorders is an often neglected topic in otolaryngology. This article evaluates current clinical practice within the United Kingdom, and provides a literature-based review of the diagnosis, management and prognosis of olfactory pathology.Design:A questionnaire was sent to consultant and associate specialist members of the British Association of Otolaryngologists and Head and Neck Surgeons. The responses were documented to gain an impression of how olfactory disorders are managed in the United Kingdom. The literature relating to olfactory dysfunction was then evaluated and the findings summarised.Conclusions:Management of olfactory pathology varies across the United Kingdom. The literature suggests that chemosensory testing is optimal and that both forced-choice and threshold testing should be applied if objective evaluation is required. Imaging can be of value but the appropriate technique should be used. Olfactory function can recover following head injury, viral infection and chronic sinonasal disease, although varying degrees of dysfunction are likely to persist. There is a role for the use of corticosteroids, particularly when administered systemically. More research is needed to establish the appropriate dose and length of treatment.
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Affiliation(s)
- E McNeill
- Department of Otolaryngology, Freeman Hospital, Newcastle-upon-Tyne, UK.
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Augusto LG. Intranasal Zinc in the Management of the Common Cold. J Pharm Pract 2006. [DOI: 10.1177/0897190006297066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Because zinc ions may prevent rhinovirus from attaching to and infecting cells in the nasal cavity, it has been recently hypothesized that direct application of ionic zinc to the nasal mucosa would be effective in reducing the duration of rhinovirus-associated colds. Five studies that compare intranasal zinc to placebo were identified in the medical literature. These studies provide conflicting results and are reviewed in detail. In the clinical trials that found efficacy, intranasal zinc was administered within the first 24 to 48 hours of the onset of cold symptoms. Adverse effects reported in clinical trials include nasal stinging or burning, epistaxis, headache, dry nose, dry mouth, nasal irritation, throat irritation, and nasal pain. Also of importance, case reports of intranasal zinc—induced persistent anosmia (complete loss of the sense of smell) have been reported in the literature. It is important that pharmacists inform their patients who want to use intranasal zinc of this possible complication.
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Affiliation(s)
- Laura Gianni Augusto
- Department of Clinical Pharmacy Practice, St John's University College of Pharmacy and Allied Health Professions, 8000 Utopia Parkway, Queens, New York 11439,
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The Efficacy of Zinc Lozenges and Zinc Nasal Sprays in the Treatment of the Common Cold. TOP CLIN NUTR 2006. [DOI: 10.1097/00008486-200610000-00012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
PURPOSE OF REVIEW Disorders of the sense of smell can result through hundreds of different processes, but most commonly occur from upper-respiratory-tract infections, trauma, and chronic rhinosinusitis. RECENT DEVELOPMENTS Research in the basic science of olfaction has progressed rapidly with powerful new molecular discoveries; however, our ability to treat these disorders remains limited. In clinical olfaction we are just realizing the broader existence of the sensory dysfunction in our population. We are discovering associations between neurodegenerative disorders and smell function that may allow us to identify these disorders earlier in the disease process. We are also challenging our previous categorization schemes and realizing that many etiologies cross the traditional conductive and neuro-sensory divisions. SUMMARY Currently, aside from the possible therapeutic potential of systemic steroids, we have no effective treatment for the most common causes of olfactory loss. Recent advances in the basic science of olfaction provides us with an opportunity to develop new and novel clinical studies in an attempt at improving the quality of life for many of these patients.
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Affiliation(s)
- Eric H Holbrook
- Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, 243 Charles Street, Boston, Massachusetts 02114, USA.
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Abstract
PURPOSE OF REVIEW Patients with advanced head and neck cancer are being treated with chemo-radiotherapy, and life is being prolonged, with or without persistent disease, for longer than was previously. Hypercalcaemia may present in patients with advanced or disseminated head and neck cancer, and, as such, these patients may present to a larger variety of clinicians for advice concerning their symptoms and illness. Modes of presentation of hypercalcaemia and treatment strategies are reviewed. RECENT FINDINGS There were previously few large series of head and neck cancer patients diagnosed with hypercalcaemia, which may or may not have been related to their cancer being treated. Investigations, by way of blood/serum calcium level, may identify such patients. Patients with cancer-related hypercalcaemia have a poor prognosis, but many may respond temporarily to treatment when offered, with an improvement of their quality of life and death. SUMMARY Hypercalcaemia should and must be considered in all patients who have or possibly have a diagnosis of a head and neck cancer and who present unwell with symptoms of fatigue, lethargy and somnolence. Investigation must include serum calcium (corrected for serum albumin binding) and parathyroid hormone level. Patients may be treated by a combination of rehydration and bisulphonate therapy until the serum calcium is reduced to a level below 3 mmol/l. The majority of patients diagnosed with hypercalcaemia due to head and neck malignancy die of their diseases in the short term, but some may enjoy a prolongation of life with reasonable quality if diagnosed and treated aggressively.
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Affiliation(s)
- Patrick J Bradley
- Department of Oto-Rhino-Laryngology, Head and Neck Surgery, University Hospital, Nottingham, UK.
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Re: Alexander TH, Davidson TM. Intranasal zinc and anosmia: the zinc-induced anosmia syndrome. Laryngoscope 2006;116:217???220. Laryngoscope 2006. [DOI: 10.1097/01.mlg.0000230480.67612.38] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Abstract
OBJECTIVE Commercial preparations of intranasal zinc gluconate gel are marketed as a remedy for the common cold. However, intranasal zinc has been reported as a cause of anosmia in humans and animals. Seventeen patients presenting with anosmia after the use of intranasal zinc gluconate are described. METHODS The authors conducted a retrospective case series of patients presenting to a nasal dysfunction clinic and conducted complete history and physical examination on all patients, including nasal endoscopy. All patients underwent detailed odor threshold and identification testing. RESULTS Threshold and identification testing revealed impaired olfaction in all patients. Inflammatory and traumatic causes of anosmia were excluded based on history, physical examination, and imaging. All patients diagnosed with zinc-induced anosmia or hyposmia reported sniffing deeply when applying the gel. This was followed by an immediate sensation of burning lasting minutes to hours. Loss of sense of smell was then perceived within 48 hours. Seven of 17 patients never developed symptoms of an upper respiratory infection. CONCLUSIONS The zinc-induced anosmia syndrome, characterized by squirt, sniff, burn, and anosmia, occurs after the exposure of olfactory epithelium to zinc cation. It can be distinguished from postviral anosmia based on history.
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Affiliation(s)
- Thomas H Alexander
- Department of Surgery, Head and Neck Surgery and Continuing Medical Education, University of California, San Diego School of Medicine, VA San Diego Healthcare System, San Diego, CA 92103, USA
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Schwiebert EM, Liang L, Cheng NL, Williams CR, Olteanu D, Welty EA, Zsembery A. Extracellular zinc and ATP-gated P2X receptor calcium entry channels: New zinc receptors as physiological sensors and therapeutic targets. Purinergic Signal 2005; 1:299-310. [PMID: 18404515 PMCID: PMC2096558 DOI: 10.1007/s11302-005-0777-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2005] [Revised: 07/06/2005] [Accepted: 07/08/2005] [Indexed: 12/15/2022] Open
Abstract
In this review, we focus on two attributes of P2X receptor channel function, one essential and one novel. First, we propose that P2X receptors are extracellular sensors as well as receptors and ion channels. In particular, the large extracellular domain (that comprises 70% of the molecular mass of the receptor channel protein) lends itself to be a cellular sensor. Moreover, its exquisite sensitivity to extracellular pH, ionic strength, and multiple ligands evokes the function of a sensor. Second, we propose that P2X receptors are extracellular zinc receptors as well as receptors for nucleotides. We provide novel data in multiple publications and illustrative data in this invited review to suggest that zinc triggers ATP-independent activation of P2X receptor channel function. In this light, P2X receptors are the cellular site of integration between autocrine and paracrine zinc signaling and autocrine and paracrine purinergic signaling. P2X receptors may sense changes in these ligands as well as in extracellular pH and ionic strength and transduce these sensations via calcium and/or sodium entry and changes in membrane potential.
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Affiliation(s)
- Erik M Schwiebert
- Department of Physiology and Biophysics, University of Alabama at Birmingham, Birmingham, Alabama, USA,
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