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Fogarty MJ, Drieberg-Thompson JR, Bellingham MC, Noakes PG. Timeline of hypoglossal motor neuron death and intrinsic tongue muscle denervation in high-copy number SOD1 G93A mice. Front Neurol 2024; 15:1422943. [PMID: 39119557 PMCID: PMC11306148 DOI: 10.3389/fneur.2024.1422943] [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: 04/24/2024] [Accepted: 07/10/2024] [Indexed: 08/10/2024] Open
Abstract
In amyotrophic lateral sclerosis (ALS) postmortem tissue and the SOD1 mouse model at mid-disease, death of hypoglossal motor neurons (XII MNs) is evident. These XII MNs innervate the intrinsic and extrinsic tongue muscles, and despite their importance in many oral and lingual motor behaviours that are affected by ALS (e.g., swallowing, speech, and respiratory functions), little is known about the timing and extent of tongue muscle denervation. Here in the well-characterised SOD1G93A (high-copy) mouse model, we evaluated XII MN numbers and intrinsic tongue muscle innervation using standard histopathological approaches, which included stereological evaluation of Nissl-stained brainstem, and the presynaptic and postsynaptic evaluation of neuromuscular junctions (NMJs), using synapsin, neurofilament, and α-bungarotoxin immunolabelling, at presymptomatic, onset, mid-disease, and endstage timepoints. We found that reduction in XII MN size at onset preceded reduced XII MN survival, while the denervation of tongue muscle did not appear until the endstage. Our study suggests that denervation-induced weakness may not be the most pertinent feature of orolingual deficits in ALS. Efforts to preserve oral and respiratory functions of XII MNs are incredibly important if we are to influence patient outcomes.
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Affiliation(s)
- Matthew J. Fogarty
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, United States
- School of Biomedical Sciences, St Lucia, QLD, Australia
| | | | | | - Peter G. Noakes
- School of Biomedical Sciences, St Lucia, QLD, Australia
- Queensland Brain Institute, St Lucia, QLD, Australia
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Wang M, Liu Y, Qiu Y, Chen H, Liwen W, Huang D, Zhang X, Li G. Predictors of Difficult Laryngeal Exposure in Suspension Laryngoscopy: A Systematic Review and Meta-Analysis. Clin Exp Otorhinolaryngol 2024; 17:177-187. [PMID: 38659242 DOI: 10.21053/ceo.2023.00023] [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: 10/26/2023] [Accepted: 04/25/2024] [Indexed: 04/26/2024] Open
Abstract
OBJECTIVES Considerable research has been focused on independent predictors of difficult laryngeal exposure (DLE) during suspension laryngoscopy. However, previous studies have yielded inconsistent results and conclusions. Consequently, we performed a meta-analysis of the existing literature with the aim of identifying significant parameters for a standardized preoperative DLE prediction system. METHODS We systematically retrieved articles from the PubMed, Embase, Web of Science, China National Knowledge Infrastructure, and Wanfang databases up to October 2022. Data from eligible studies were extracted and analyzed using the R programming language. The effect measures included odds ratios (ORs) with 95% confidence intervals (CIs) for dichotomous variables and mean differences (MDs) with 95% CIs for continuous variables. RESULTS The search yielded 1,574 studies, of which 18 (involving a total of 2,263 patients) were included. Pooled analysis demonstrated that patients with DLE during microsurgery tended to be male (OR, 1.73; 95% CI, 1.16-2.57); were older (MD, 5.47 years, 95% CI, 2.44-8.51 years); had a higher body mass index (BMI; MD, 1.19 kg/m2; 95% CI, 0.33-2.05 kg/m2); had a greater neck circumference (MD, 2.50 cm; 95% CI, 1.56-3.44 cm); exhibited limited mouth opening (MD, -0.52 cm; 95% CI, -0.88 to -0.15 cm); had limited neck flexibility (MD, -10.05 cm; 95% CI, -14.10 to -6.00 cm); displayed various other anatomical characteristics; and had a high modified Mallampati index (MMI) or test score (OR, 3.37; 95% CI, 2.07-5.48). CONCLUSION We conducted a comprehensive and systematic analysis of the factors relevant to DLE. Ultimately, we identified sex, age, BMI, neck circumference, MMI, inter-incisor gap, hyomental distance, thyromental distance, sternomental distance, and flexion-extension angle as factors highly correlated with DLE.
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Affiliation(s)
- Mengshu Wang
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Changsha, China
- Otolaryngology Major Disease Research, Key Laboratory of Hunan Province, Changsha, China
- Clinical Research Center for Pharyngolaryngeal Diseases and Voice Disorders in Hunan Province, Changsha, China
| | - Yong Liu
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Changsha, China
- Otolaryngology Major Disease Research, Key Laboratory of Hunan Province, Changsha, China
- Clinical Research Center for Pharyngolaryngeal Diseases and Voice Disorders in Hunan Province, Changsha, China
- National Clinical Research Center for Geriatric Disorders (Xiangya Hospital), Changsha, China
| | - Yuanzheng Qiu
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Changsha, China
- Otolaryngology Major Disease Research, Key Laboratory of Hunan Province, Changsha, China
- Clinical Research Center for Pharyngolaryngeal Diseases and Voice Disorders in Hunan Province, Changsha, China
- National Clinical Research Center for Geriatric Disorders (Xiangya Hospital), Changsha, China
| | - Huihong Chen
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Changsha, China
- Otolaryngology Major Disease Research, Key Laboratory of Hunan Province, Changsha, China
- Clinical Research Center for Pharyngolaryngeal Diseases and Voice Disorders in Hunan Province, Changsha, China
| | - Wang Liwen
- Department of Hematology, Third Xiangya Hospital, Central South University, Changsha, China
| | - Donghai Huang
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Changsha, China
- Otolaryngology Major Disease Research, Key Laboratory of Hunan Province, Changsha, China
- Clinical Research Center for Pharyngolaryngeal Diseases and Voice Disorders in Hunan Province, Changsha, China
| | - Xin Zhang
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Changsha, China
- Otolaryngology Major Disease Research, Key Laboratory of Hunan Province, Changsha, China
- Clinical Research Center for Pharyngolaryngeal Diseases and Voice Disorders in Hunan Province, Changsha, China
- National Clinical Research Center for Geriatric Disorders (Xiangya Hospital), Changsha, China
| | - Guo Li
- Department of Otolaryngology Head and Neck Surgery, Xiangya Hospital, Central South University, Changsha, China
- Otolaryngology Major Disease Research, Key Laboratory of Hunan Province, Changsha, China
- Clinical Research Center for Pharyngolaryngeal Diseases and Voice Disorders in Hunan Province, Changsha, China
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Sieck GC, Hernandez-Vizcarrondo GA, Brown AD, Fogarty MJ. Sarcopenia of the longitudinal tongue muscles in rats. Respir Physiol Neurobiol 2024; 319:104180. [PMID: 37863156 PMCID: PMC10851598 DOI: 10.1016/j.resp.2023.104180] [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: 08/08/2023] [Revised: 09/29/2023] [Accepted: 10/14/2023] [Indexed: 10/22/2023]
Abstract
The tongue is a muscular hydrostat, with lingual movements occurring during breathing, chewing, swallowing, vocalization, vomiting, coughing and grooming/sexual activities. In the elderly, reduced lingual dysfunction and weakness contribute to increased risks of obstructive sleep apnea and aspiration pneumonia. In Fischer 344 (F344) rats, a validated model of aging, hypoglossal motor neuron death is apparent, although there is no information regarding tongue strength. The intrinsic tongue muscles, the superior and inferior longitudinal, transversalis and verticalis exist in an interdigitated state. Recently, we established a method to measure the specific force of individual intrinsic tongue muscle, accounting for the tissue bulk that is not in the direction of uniaxial force. In the longitudinal muscles of 6- (n = 10), 18- (n = 9) and 24-month-old (n = 12) female and male F344 rats, we assessed specific force, fatigability, fiber type dependent cross-sectional area (CSA) and overall CSA. Muscle force and fatigue was assessed ex vivo using platinum plate simulation electrodes. Tongue muscles were frozen in melting isopentane, and transverse sections cut at 10 µm. Muscle fiber type was classified based on immunoreactivity to myosin heavy chain (MyHC) isoform antibodies. In H&E stained muscle, CSA and uniaxial muscle contributions to total tongue bulk was assessed. We observed a robust ∼30% loss of longitudinal specific force, with reductions in overall longitudinal muscle fiber CSA and specific atrophy of type IIx/IIb fibers. It will be important to investigate the mechanistic underpinnings of hypoglossal motor neuron death and tongue muscle weakness to eventually provide therapies for age-associated lingual dysfunctions.
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Affiliation(s)
- Gary C Sieck
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA
| | | | - Alyssa D Brown
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA
| | - Matthew J Fogarty
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA.
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4
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Mathis S, Solé G, Damon-Perrière N, Rouanet-Larrivière M, Duval F, Prigent J, Nadal L, Péréon Y, Le Masson G. Clinical Neurology in Practice: The Tongue (Part 1). Neurologist 2023; 28:338-348. [PMID: 37639535 DOI: 10.1097/nrl.0000000000000512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
BACKGROUND The tongue is an essential organ for the development of certain crucial functions, such as swallowing and language. The examination of the tongue can be very useful in neurology, as the various types of lingual alterations can lead to certain specific diagnoses, the tongue being a kind of "mirror" of some neurological function. REVIEW SUMMARY In this study, we reviewed the literature on anatomy, physiology, and the various aspects of the examination of the tongue. CONCLUSIONS Examination of the tongue should be an integral part of the clinical examination of the cranial nerves. This study aimed to demonstrate the importance of tongue motor and non-motor functions in neurological practice.
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Affiliation(s)
- Stéphane Mathis
- Department of Neurology, Muscle-Nerve
- Referral Center for Neuromuscular Diseases 'AOC'
- ALS Center
| | - Guilhem Solé
- Department of Neurology, Muscle-Nerve
- Referral Center for Neuromuscular Diseases 'AOC'
| | - Nathalie Damon-Perrière
- Department of Clinical Neurophysiology
- Department of Movement Disorders, University Hospitals of Bordeaux (CHU Bordeaux, Amélie Raba-Léon, Bordeaux
| | | | - Fanny Duval
- Department of Neurology, Muscle-Nerve
- Referral Center for Neuromuscular Diseases 'AOC'
| | | | | | - Yann Péréon
- Reference Centre for Neuromuscular Diseases 'AOC'. Filenemus, Euro-NMD, University Hospitals of Nantes (CHU Nantes), Nantes, France
| | - Gwendal Le Masson
- Department of Neurology, Muscle-Nerve
- Referral Center for Neuromuscular Diseases 'AOC'
- ALS Center
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5
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Fogarty MJ. Loss of larger hypoglossal motor neurons in aged Fischer 344 rats. Respir Physiol Neurobiol 2023:104092. [PMID: 37331418 DOI: 10.1016/j.resp.2023.104092] [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: 05/05/2023] [Revised: 06/06/2023] [Accepted: 06/15/2023] [Indexed: 06/20/2023]
Abstract
The intrinsic (longitudinal, transversalis and verticalis) and extrinsic (genioglossus, styloglossus, hyoglossus and geniohyoid) tongue muscles are innervated by hypoglossal motor neurons (MNs). Tongue muscle activations occur during many behaviors: maintaining upper airway patency, chewing, swallowing, vocalization, vomiting, coughing, sneezing and grooming/sexual activities. In the tongues of the elderly, reduced oral motor function and strength contribute to increased risk of obstructive sleep apnoea. Tongue muscle atrophy and weakness is also described in rats, yet hypoglossal MN numbers are unknown. In young (6-months, n=10) and old (24-months, n=8) female and male Fischer 344 (F344) rats, stereological assessment of hypoglossal MN numbers and surface areas were performed on 16µm Nissl-stained brainstem cryosections. We observed a robust loss of ~15% of hypoglossal MNs and a modest ~8% reduction in their surface areas with age. In the larger size tertile of hypoglossal MNs, age-associated loss of hypoglossal MNs approached ~30% These findings uncover a potential neurogenic locus of pathology for age-associated tongue dysfunctions.
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Affiliation(s)
- Matthew J Fogarty
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN 55905.
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Doyle ME, Premathilake HU, Yao Q, Mazucanti CH, Egan JM. Physiology of the tongue with emphasis on taste transduction. Physiol Rev 2023; 103:1193-1246. [PMID: 36422992 PMCID: PMC9942923 DOI: 10.1152/physrev.00012.2022] [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] [Indexed: 11/25/2022] Open
Abstract
The tongue is a complex multifunctional organ that interacts and senses both interoceptively and exteroceptively. Although it is easily visible to almost all of us, it is relatively understudied and what is in the literature is often contradictory or is not comprehensively reported. The tongue is both a motor and a sensory organ: motor in that it is required for speech and mastication, and sensory in that it receives information to be relayed to the central nervous system pertaining to the safety and quality of the contents of the oral cavity. Additionally, the tongue and its taste apparatus form part of an innate immune surveillance system. For example, loss or alteration in taste perception can be an early indication of infection as became evident during the present global SARS-CoV-2 pandemic. Here, we particularly emphasize the latest updates in the mechanisms of taste perception, taste bud formation and adult taste bud renewal, and the presence and effects of hormones on taste perception, review the understudied lingual immune system with specific reference to SARS-CoV-2, discuss nascent work on tongue microbiome, as well as address the effect of systemic disease on tongue structure and function, especially in relation to taste.
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Affiliation(s)
- Máire E Doyle
- Diabetes Section/Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Hasitha U Premathilake
- Diabetes Section/Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Qin Yao
- Diabetes Section/Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Caio H Mazucanti
- Diabetes Section/Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Josephine M Egan
- Diabetes Section/Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
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7
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Svandova E, Lesot H, Sharpe P, Matalova E. Making the head: Caspases in life and death. Front Cell Dev Biol 2023; 10:1075751. [PMID: 36712975 PMCID: PMC9880857 DOI: 10.3389/fcell.2022.1075751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 12/29/2022] [Indexed: 01/14/2023] Open
Abstract
The term apoptosis, as a way of programmed cell death, was coined a half century ago and since its discovery the process has been extensively investigated. The anatomy and physiology of the head are complex and thus apoptosis has mostly been followed in separate structures, tissues or cell types. This review aims to provide a comprehensive overview of recent knowledge concerning apoptosis-related molecules involved in the development of structures of head with a particular focus on caspases, cysteine proteases having a key position in apoptotic pathways. Since many classical apoptosis-related molecules, including caspases, are emerging in several non-apoptotic processes, these were also considered. The largest organ of the head region is the brain and its development has been extensively investigated, including the roles of apoptosis and related molecules. Neurogenesis research also includes sensory organs such as the eye and ear, efferent nervous system and associated muscles and glands. Caspases have been also associated with normal function of the skin and hair follicles. Regarding mineralised tissues within craniofacial morphogenesis, apoptosis in bones has been of interest along with palate fusion and tooth development. Finally, the role of apoptosis and caspases in angiogenesis, necessary for any tissue/organ development and maintenance/homeostasis, are discussed. Additionally, this review points to abnormalities of development resulting from improper expression/activation of apoptosis-related molecules.
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Affiliation(s)
- Eva Svandova
- Faculty of Medicine, Masaryk University, Brno, Czechia
| | - Herve Lesot
- Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Brno, Czechia
| | - Paul Sharpe
- Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Brno, Czechia
- Centre for Craniofacial and Regenerative Biology, Faculty of Dentistry, Oral, and Craniofacial Sciences, King’s College London, London, United Kingdom
| | - Eva Matalova
- Department of Physiology, University of Veterinary Sciences, Brno, Czechia
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8
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Mueller M, Thompson R, Osman KL, Andel E, Dejonge C, Kington S, Stephenson Z, Hamad A, Bunyak F, Nichols NL, Lever TE. Impact of Limb Phenotype on Tongue Denervation Atrophy, Dysphagia Penetrance, and Survival Time in a Mouse Model of ALS. Dysphagia 2022; 37:1777-1795. [PMID: 35426522 PMCID: PMC9568622 DOI: 10.1007/s00455-022-10442-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 03/28/2022] [Indexed: 12/16/2022]
Abstract
Current treatments for dysphagia in ALS do not target the underlying tongue weakness and denervation atrophy that is prevalent in spinal and bulbar ALS cases. To address this clinical gap, we studied the low copy number SOD1-G93A (LCN-SOD1) mouse model of ALS to quantify the impact of limb phenotype on tongue denervation atrophy, dysphagia penetrance, and survival time in preparation for future treatment-based studies. Two male LCN-SOD1 breeders and 125 offspring were followed for limb phenotype inheritance, of which 52 (30 LCN-SOD1 and 22 wild-type/WT, both sexes) underwent characterization of dysphagia penetrance (via videofluoroscopic swallow study; VFSS) and survival time at disease end-stage (15-20% body weight loss). From these, 16 mice (8/genotype) underwent postmortem histological analysis of the genioglossus for evidence of denervation atrophy. Results revealed that both breeders displayed a mixed (hindlimb and forelimb) ALS phenotype and sired equal proportions of hindlimb vs. mixed phenotype offspring. Dysphagia penetrance was complete for mixed (100%) versus incomplete for hindlimb (64%) phenotype mice; yet survival times were similar. Regardless of limb phenotype, LCN-SOD1 mice had significantly smaller genioglossus myofibers and more centralized myonuclei compared to WT mice (p < 0.05). These biomarkers of denervation atrophy were significantly correlated with VFSS metrics (lick and swallow rates, p < 0.05) but not survival time. In conclusion, both LCN-SOD1 phenotypes had significant tongue denervation atrophy, even hindlimb phenotype mice without dysphagia. This finding recapitulates human ALS, providing robust rationale for using this preclinical model to explore targeted treatments for tongue denervation atrophy and ensuing dysphagia.
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Affiliation(s)
| | | | - Kate L. Osman
- Department of Otolaryngology – Head and Neck Surgery, University of Missouri School of Medicine, Columbia, MO, USA
| | - Ellyn Andel
- University of Missouri Students, Columbia, MO, USA
| | | | | | | | - Ali Hamad
- University of Missouri Students, Columbia, MO, USA
| | - Filiz Bunyak
- Department of Electrical Engineering and Computer Science, University of Missouri College of Engineering, Columbia, MO, USA
| | - Nicole L. Nichols
- Department of Biomedical Sciences, University of Missouri College of Veterinary Medicine, Columbia, MO, USA
| | - Teresa E. Lever
- Department of Otolaryngology – Head and Neck Surgery, University of Missouri School of Medicine, Columbia, MO, USA,Department of Biomedical Sciences, University of Missouri College of Veterinary Medicine, Columbia, MO, USA
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9
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Fogarty MJ, Sieck GC. Tongue muscle contractile, fatigue, and fiber type properties in rats. J Appl Physiol (1985) 2021; 131:1043-1055. [PMID: 34323593 DOI: 10.1152/japplphysiol.00329.2021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The intrinsic and extrinsic tongue muscles manipulate the position and shape of the tongue and are activated during many oral and respiratory behaviors. In the present study, in 6-mo-old Fischer 344 rats, we examined mechanical and fatigue properties of tongue muscles in relation to their fiber type composition. In an ex vivo preparation, isometric force and fatigue was assessed by direct muscle stimulation. Tongue muscles were frozen in melting isopentane and transverse sections cut at 10 µm. In hematoxylin-eosin (H&E)-stained muscle sections, the relative fractions of muscle versus extracellular matrix were determined. Muscle fibers were classified as type I, IIa and IIx, and/or IIb based on immunoreactivity to specific myosin heavy chain isoform antibodies. Cross-sectional areas (CSAs) and proportions of different fiber types were used to calculate their relative contribution to total muscle CSAs. We found that the superior and inferior longitudinal intrinsic muscles (4.4 N/cm2) and genioglossus muscle (3.0 N/cm2) generated the greatest maximum isometric force compared with the transversalis muscle (0.9 N/cm2). The longitudinal muscles and the transversalis muscle displayed greater fatigue during repetitive stimulation consistent with the greater relative contribution of type IIx and/or IIb fibers. By contrast, the genioglossus, comprising a higher proportion of type I and IIa fibers, was more fatigue resistant. This study advances our understanding of the force, fatigue, and fiber type-specific properties of individual tongue musculature. The assessments and approach provide a readily accessible muscular readout for scenarios where motor control dysfunction or tongue weakness is evident.NEW & NOTEWORTHY For the individual tongue muscles, relatively little quantification of uniaxial force, fatigue, and fiber type-specific properties has been documented. Here, we assessed uniaxial-specific force generation, fatigability, and muscle fiber type-specific properties in the superior and inferior longitudinal muscles, the transversalis, and the genioglossus in Fischer 344 rats. The longitudinal muscles produced the greatest isometric tetanic-specific forces. The genioglossus was more fatigue resistant and comprised higher proportions of I and IIa fibers.
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Affiliation(s)
- Matthew J Fogarty
- Department of Physiology and Biomedical Engineering, grid.66875.3aMayo Clinic, Rochester, Minnesota
| | - Gary C Sieck
- Department of Physiology and Biomedical Engineering, grid.66875.3aMayo Clinic, Rochester, Minnesota
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10
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Lind LA, Lever TE, Nichols NL. Tongue and hypoglossal morphology after intralingual cholera toxin B-saporin injection. Muscle Nerve 2020; 63:413-420. [PMID: 33269488 DOI: 10.1002/mus.27131] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 11/23/2020] [Accepted: 11/27/2020] [Indexed: 01/23/2023]
Abstract
INTRODUCTION We recently developed an inducible model of dysphagia using intralingual injection of cholera toxin B conjugated to saporin (CTB-SAP) to cause death of hypoglossal neurons. In this study we aimed to evaluate tongue morphology and ultrastructural changes in hypoglossal neurons and nerve fibers in this model. METHODS Tissues were collected from 20 rats (10 control and 10 CTB-SAP animals) on day 9 post-injection. Tongues were weighed, measured, and analyzed for microscopic changes using laminin immunohistochemistry. Hypoglossal neurons and axons were examined using transmission electron microscopy. RESULTS The cross-sectional area of myofibers in the posterior genioglossus was decreased in CTB-SAP-injected rats. Degenerative changes were observed in both the cell bodies and distal axons of hypoglossal neurons. DISCUSSION Preliminary results indicate this model may have translational application to a variety of neurodegenerative diseases resulting in tongue dysfunction and associated dysphagia.
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Affiliation(s)
- Lori A Lind
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri, USA
| | - Teresa E Lever
- Department of Otolaryngology-Head and Neck Surgery, University of Missouri, Columbia, Missouri, USA
| | - Nicole L Nichols
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri, USA
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11
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Kletzien H, Kelm-Nelson CA, Wang S, Suzuki M, Connor NP. Myogenic marker expression as a function of age and exercise-based therapy in the tongue. Exp Gerontol 2020; 142:111104. [PMID: 33017670 PMCID: PMC7748063 DOI: 10.1016/j.exger.2020.111104] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 08/29/2020] [Accepted: 09/24/2020] [Indexed: 12/30/2022]
Abstract
Degeneration of tongue muscles with aging may contribute to swallowing deficits observed in elderly people. However, the capacity for tongue muscle stem cells (SCs) to regenerate and repair the aged tongue and improve tongue strength following tongue exercise (a current clinical treatment) has never been examined. We found that the expression of regenerative, myogenic markers were impaired with age and may be related to increased expression of senescent marker p16INK4a. Tongue strength increased in young adult and old rats following exercise and was related to the expression of Pax7, MyoD, myogenin, and p16INK4a. Our study also suggests that strengthening of tongue muscles via clinical rehabilitation strategies also increased the expression of SC regenerative markers in the tongue throughout the exercise duration.
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Affiliation(s)
- Heidi Kletzien
- Department of Biomedical Engineering, University of Wisconsin-Madison, United States of America; Department of Surgery, University of Wisconsin School of Medicine and Public Health, United States of America; Department of Stem Cell and Regenerative Biology, Harvard University, United States of America.
| | - Cynthia A Kelm-Nelson
- Department of Surgery, University of Wisconsin School of Medicine and Public Health, United States of America
| | - Sabrina Wang
- Department of Surgery, University of Wisconsin School of Medicine and Public Health, United States of America
| | - Masatoshi Suzuki
- Department of Biomedical Engineering, University of Wisconsin-Madison, United States of America; Department of Comparative Biosciences, University of Wisconsin-Madison, United States of America
| | - Nadine P Connor
- Department of Surgery, University of Wisconsin School of Medicine and Public Health, United States of America; Department of Communication Sciences and Disorders, University of Wisconsin-Madison, United States of America
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12
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A study of chewing muscles: Age-related changes in type I collagen and matrix metalloproteinase-2 expression. Arch Oral Biol 2019; 109:104583. [PMID: 31706109 DOI: 10.1016/j.archoralbio.2019.104583] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 09/23/2019] [Accepted: 10/03/2019] [Indexed: 12/22/2022]
Abstract
OBJECTIVE In this study, the aim was to investigate the biochemical, physiological and histological changes that occur in masticatory muscles of the masticatory system with aging. DESIGN In this study, 14 BALB/c mice were used. Animals were divided into two equal groups of seven. Group I was organized as the group of young animals (n = 7) and Group II as the group of adult animals (n = 7). After routine histological follow-up was performed, the tissues were embedded in paraffin. 4-5 μm thick cross-sections were taken from paraffin-embedded tissues and they were stained with Haemotoxylin and Eosin Type I collagen and Matrix metalloproteinase-2 (MMP-2) immunohistochemically. RESULTS It was observed that there was a decrease and shrinking in blood vessels due to aging. In young mice, Type I collagen and MMP-2 immunoreactivity in the masseter muscle tissue showed low staining, while Type I collagen and MMP-2 immunoreactivity in the temporal muscle tissue showed moderate staining. Type I collagen and MMP-2 immunoreactivity were significantly higher in the masseter and temporal muscles of elderly mice (p = 0.001). In the H-score evaluation, MMP-2 immune reactivity was significantly lower in young mice than in older mice (p = 0.001). CONCLUSION It was determined that severe pain complications and functional losses are likely to occur with the increase of degeneration due to aging of masticator muscles.
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Schwartz LM. Skeletal Muscles Do Not Undergo Apoptosis During Either Atrophy or Programmed Cell Death-Revisiting the Myonuclear Domain Hypothesis. Front Physiol 2019; 9:1887. [PMID: 30740060 PMCID: PMC6356110 DOI: 10.3389/fphys.2018.01887] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 12/12/2018] [Indexed: 12/20/2022] Open
Abstract
Skeletal muscles are the largest cells in the body and are one of the few syncytial ones. There is a longstanding belief that a given nucleus controls a defined volume of cytoplasm, so when a muscle grows (hypertrophy) or shrinks (atrophy), the number of myonuclei change accordingly. This phenomenon is known as the “myonuclear domain hypothesis.” There is a general agreement that hypertrophy is accompanied by the addition of new nuclei from stem cells to help the muscles meet the enhanced synthetic demands of a larger cell. However, there is a considerable controversy regarding the fate of pre-existing nuclei during atrophy. Many researchers have reported that atrophy is accompanied by the dramatic loss of myonuclei via apoptosis. However, since there are many different non-muscle cell populations that reside within the tissue, these experiments cannot easily distinguish true myonuclei from those of neighboring mononuclear cells. Recently, two independent models, one from rodents and the other from insects, have demonstrated that nuclei are not lost from skeletal muscle fibers when they undergo either atrophy or programmed cell death. These and other data argue against the current interpretation of the myonuclear domain hypothesis and suggest that once a nucleus has been acquired by a muscle fiber it persists.
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Affiliation(s)
- Lawrence M Schwartz
- Department of Biology, Morrill Science Center, University of Massachusetts, Amherst, MA, United States
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Kletzien H, Cullins MJ, Connor NP. Age-related alterations in swallowing biomechanics. Exp Gerontol 2019; 118:45-50. [PMID: 30633957 DOI: 10.1016/j.exger.2019.01.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 12/14/2018] [Accepted: 01/06/2019] [Indexed: 11/26/2022]
Abstract
BACKGROUND Aging rodent models allow for the discovery of underlying mechanisms of cranial muscle dysfunction. Methods are needed to allow quantification of complex, multivariate biomechanical movements during swallowing. Videofluoroscopic swallow studies (VSS) are the standard of care in assessment of swallowing disorders in patients and validated quantitative, kinematic, and morphometric analysis methods have been developed. Our purpose was to adapt validated morphometric techniques to the rodent to computationally analyze swallowing dysfunction in the aging rodent. METHODS VSS, quantitative analyses (bolus area, bolus velocity, mastication rate) and a rodent specific multivariate, morphometric computational analysis of swallowing biomechanics were performed on 20 swallows from 5 young adult and 5 old Fischer 344/Brown Norway rats. Eight anatomical landmarks were used to track the relative change in position of skeletal levers (cranial base, vertebral column, mandible) and soft tissue landmarks (upper esophageal sphincter, base of tongue). RESULTS Bolus area significantly increased and mastication rate significantly decreased with age. Aging accounted for 77.1% of the variance in swallow biomechanics, and 18.7% of the variance was associated with swallow phase (oral vs pharyngeal). Post hoc analyses identified age-related alterations in tongue base retraction, mastication, and head posture during the swallow. CONCLUSION Geometric morphometric analysis of rodent swallows suggests that swallow biomechanics are altered with age. When used in combination with biological assays of age-related adaptations in neuromuscular systems, this multivariate analysis may increase our understanding of underlying musculoskeletal dysfunction that contributes to swallowing disorders with aging.
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Affiliation(s)
- Heidi Kletzien
- Division of Otolaryngology-Head and Neck Cancer, Department of Surgery, University of Wisconsin School of Medicine and Public Health, United States of America; Department of Biomedical Engineering, University of Wisconsin-Madison, United States of America.
| | - Miranda J Cullins
- Division of Otolaryngology-Head and Neck Cancer, Department of Surgery, University of Wisconsin School of Medicine and Public Health, United States of America
| | - Nadine P Connor
- Division of Otolaryngology-Head and Neck Cancer, Department of Surgery, University of Wisconsin School of Medicine and Public Health, United States of America; Department of Biomedical Engineering, University of Wisconsin-Madison, United States of America; Department of Communication Sciences and Disorders, University of Wisconsin-Madison, United States of America
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Nagano A, Nishioka S, Wakabayashi H. Rehabilitation Nutrition for Iatrogenic Sarcopenia and Sarcopenic Dysphagia. J Nutr Health Aging 2019; 23:256-265. [PMID: 30820514 DOI: 10.1007/s12603-018-1150-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Sarcopenia is a very important issue in rehabilitation medicine and nutritional care. The prevalence of sarcopenia in older people is approximately 50% in the rehabilitation setting, and also approximately 15% of inpatients without sarcopenia upon admission developed sarcopenia during hospitalization. There is a concern that secondary sarcopenia may occur iatrogenically during hospitalization. Iatrogenic sarcopenia is defined as sarcopenia caused by the activities of medical staff including doctors, nurses, or other health care professionals in healthcare facilities. Iatrogenic sarcopenia is categorized into activity-related, nutrition-related and disease-related-iatrogenic sarcopenia. Especially in acute phase hospitals, concentrating on the treatment of diseases with less attention to nutrition and activity is more likely to cause iatrogenic sarcopenia. Sarcopenic dysphagia is also an important aspect in rehabilitation medicine and nutritional care. Sarcopenic dysphagia is characterized by swallowing difficulty because of a loss of mass and function in whole-body skeletal and swallowing muscles. Sarcopenic dysphagia can be diagnosed using a 5-step algorithm for the condition. Iatrogenic sarcopenia and sarcopenic dysphagia are affected by nutrition, activity and diseases in a complex manner. Therefore, treatment of iatrogenic sarcopenia and sarcopenic dysphagia requires comprehensive interventions through nutrition management and rehabilitation. Rehabilitation nutrition is effective for preventing and treating iatrogenic sarcopenia and sarcopenic dysphagia. Rehabilitation nutrition can be practiced more effectively and comprehensively by using the rehabilitation nutrition care process, which is a systematic problem-solving method. Further research is required to verify the efficacy of rehabilitation nutrition for preventing or improving iatrogenic sarcopenia and/or sarcopenic dysphagia.
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Affiliation(s)
- A Nagano
- Hidetaka Wakabayashi, Department of Rehabilitation Medicine, Yokohama City University Medical Center, 4-57 Urafune-cho, Minami ward, Yokohama, Kanagawa, Japan, Tel: +81-45-261-5656 Fax: +81-45-253-9955, E-mail:
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