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Anthony B, Parker N, Patel R, Halum S. Surgical Considerations for Laryngeal Reinnervation and Future Research Directions. Curr Otorhinolaryngol Rep 2020. [DOI: 10.1007/s40136-020-00294-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Abstract
Recurrent laryngeal nerve (RLN) injury has considerable clinical implications, including voice and swallowing dysfunction, which may considerably impair the patient’s quality of life. Recovery of vocal fold movement is an essential novel treatment option for RLN injury. The potential of gene therapy for addressing this issue is highly promising. The target sites for RLN gene therapy are the central nervous system, nerve fibers, laryngeal muscles, and vocal cord mucosa. Gene transduction has been reported in each site using viral or non-viral methods. The major issues ensuing after RLN injury are loss of motoneurons in the nucleus ambiguus, degeneration and poor regeneration of nerve fibers and motor end plates, and laryngeal muscle atrophy. Gene therapy using neurotrophic factors has been assessed for most of these issues, and its efficacy has been reported. Another important matter for functional vocal fold movement recovery is misdirected regeneration, in which the wrong neurons may innervate other laryngeal muscles, where even if innervation is reestablished, proper motor function is not restored. Novel strategies involving gene therapy bear promise for overcoming this issue and further investigations are underway.
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Affiliation(s)
- Koji Araki
- Department of Otolaryngology-Head & Neck Surgery, National Defense Medical College, Saitama 3598513, Japan.
| | - Hiroshi Suzuki
- Department of Otolaryngology-Head & Neck Surgery, National Defense Medical College, Saitama 3598513, Japan.
| | - Kosuke Uno
- Department of Otolaryngology-Head & Neck Surgery, National Defense Medical College, Saitama 3598513, Japan.
| | - Masayuki Tomifuji
- Department of Otolaryngology-Head & Neck Surgery, National Defense Medical College, Saitama 3598513, Japan.
| | - Akihiro Shiotani
- Department of Otolaryngology-Head & Neck Surgery, National Defense Medical College, Saitama 3598513, Japan.
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Francis HW, Papel I, Lina I, Koch W, Tunkel D, Fuchs P, Lin S, Kennedy D, Ruben R, Linthicum F, Marsh B, Best S, Carey J, Lane A, Byrne P, Flint P, Eisele DW. Otolaryngology-head and neck surgery at Johns Hopkins: The first 100 years (1914-2014). Laryngoscope 2015; 125 Suppl 9:S1-35. [PMID: 26297867 PMCID: PMC4696071 DOI: 10.1002/lary.25490] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2015] [Indexed: 12/19/2022]
Affiliation(s)
- Howard W Francis
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - Ira Papel
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - Ioan Lina
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - Wayne Koch
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - David Tunkel
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - Paul Fuchs
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - Sandra Lin
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - David Kennedy
- the Department of Otolaryngology-Head and Neck Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Robert Ruben
- the Departments ofOtorhinolaryngology-Head and Neck Surgery and Pediatrics, Albert Einstein College of Medicine Montefiore Medical Center, New York, New York
| | - Fred Linthicum
- the Department of Otolaryngology-Head and Neck Surgery, University of California at Los Angeles, Los Angeles, California
| | - Bernard Marsh
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - Simon Best
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - John Carey
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - Andrew Lane
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - Patrick Byrne
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
| | - Paul Flint
- Department of Otolaryngology-Head and Neck Surgery, Oregon Health Sciences University, Portland, Oregon, U.S.A
| | - David W Eisele
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, Maryland
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Kodama H, Kumai Y, Nishimoto K, Sanuki T, Yumoto E. Modulation of satellite cells activity and MyoD in rat thyroarytenoid muscle after reinnervation. Laryngoscope 2015; 125:E245-51. [PMID: 25809587 DOI: 10.1002/lary.25248] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 01/14/2015] [Accepted: 02/12/2015] [Indexed: 12/24/2022]
Abstract
OBJECTIVES/HYPOTHESIS To examine modulation of M-cadherin, a marker for satellite cells (SCs); and MyoD, which may indicate the myogenic activity following recurrent laryngeal nerve (RLN) denervation and immediate reinnervation; and to elucidate the correlation between their modulations and establishment of neuromuscular junctions (NMJs) in the reinnervated rat thyroarytenoid (TA) muscle. STUDY DESIGN Quantitative real-time polymerase chain reaction qPCR and histologic assessment of the TA muscle following RLN transection and anastomosis. METHODS Rats were divided into three groups: 1) denervation alone (DNV) (n = 60), 2) denervation with anastomosis (ANS) (n = 60), and 3) sham-operated controls (n = 12). Animals were sacrificed at 3 days and 1, 3, and 5 weeks after treatment. TA muscles harvested from 40 animals from each DNV and ANS group; all of sham group were subjected to qPCR for assessment of the modulation of M-cadherin and MyoD; and the remaining larynges of DNV and ANS group were used for histologic analysis. RESULTS The expression levels of messenger RNAs (mRNAs) encoding M-cadherin and MyoD in the TA muscle of the DNV group were significantly higher (P < 0.05) than in the control throughout the study period. These mRNA levels in the ANS group were significantly higher (P < 0.05) at ≤ 1 week than in the controls but fell to control levels at ≥ 3 weeks. In the ANS group, recovery of muscle area and NMJs structure occurred by 3 weeks. CONCLUSION These data suggested that NMJ formation following reinnervation might prompt recovery of M-cadherin and MyoD mRNA expression to the quiescent level of SCs.
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Affiliation(s)
- Haruka Kodama
- Department of Otolaryngology Head and Neck Surgery, Kumamoto University, Graduate School of Medicine, Kumamoto, Japan
| | - Yoshihiko Kumai
- Department of Otolaryngology Head and Neck Surgery, Kumamoto University, Graduate School of Medicine, Kumamoto, Japan
| | - Kohei Nishimoto
- Department of Otolaryngology Head and Neck Surgery, Kumamoto University, Graduate School of Medicine, Kumamoto, Japan
| | - Tetsuji Sanuki
- Department of Otolaryngology Head and Neck Surgery, Kumamoto University, Graduate School of Medicine, Kumamoto, Japan
| | - Eiji Yumoto
- Department of Otolaryngology Head and Neck Surgery, Kumamoto University, Graduate School of Medicine, Kumamoto, Japan
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Faroni A, Mobasseri SA, Kingham PJ, Reid AJ. Peripheral nerve regeneration: experimental strategies and future perspectives. Adv Drug Deliv Rev 2015; 82-83:160-7. [PMID: 25446133 DOI: 10.1016/j.addr.2014.11.010] [Citation(s) in RCA: 353] [Impact Index Per Article: 39.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Revised: 09/01/2014] [Accepted: 11/08/2014] [Indexed: 12/15/2022]
Abstract
Peripheral nerve injuries represent a substantial clinical problem with insufficient or unsatisfactory treatment options. This review summarises all the events occurring after nerve damage at the level of the cell body, the site of injury and the target organ. Various experimental strategies to improve neuronal survival, axonal regeneration and target reinnervation are described including pharmacological approaches and cell-based therapies. Given the complexity of nerve regeneration, further studies are needed to address the biology of nerve injury, to improve the interaction with implantable scaffolds, and to implement cell-based therapies in nerve tissue engineering.
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Halum SL, McRae B, Bijangi-Vishehsaraei K, Hiatt K. Neurotrophic factor-secreting autologous muscle stem cell therapy for the treatment of laryngeal denervation injury. Laryngoscope 2012; 122:2482-96. [PMID: 22965802 DOI: 10.1002/lary.23519] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 04/03/2012] [Accepted: 05/23/2012] [Indexed: 01/10/2023]
Abstract
OBJECTIVES/HYPOTHESIS To determine if the spontaneous reinnervation that characteristically ensues after recurrent laryngeal nerve (RLN) injury could be selectively promoted and directed to certain laryngeal muscles with the use of neurotrophic factor (NF)-secreting muscle stem cell (MSC) vectors while antagonistic reinnervation is inhibited with vincristine (VNC). STUDY DESIGN Basic science investigation involving primary cell cultures, gene cloning/transfer, and animal experiments. METHODS MSC survival assays were used to test multiple individual NFs in vitro. Motoneuron outgrowth assays assessed the trophic effects of identified NF on cranial nerve X (CNX)-derived motoneurons in vitro. Therapeutic NF was cloned into a lentiviral vector, and MSCs were transduced to secrete NF. Sixty rats underwent left RLN transection injury, and at 3 weeks received injections of either MSCs (n = 24), MSCs secreting NF (n = 24), or saline (n = 12) into the left thyroarytenoid muscle complex; half of the animals in the MSC groups simultaneously received left posterior cricoarytenoid injections of VNC, whereas half of the animals received saline. RESULTS Ciliary neurotrophic factor (CNTF) had the greatest survival-promoting effect on MSCs in culture. The addition of CNTF (50 ng/mL) to CNX motoneuron cultures resulted in enhanced neurite outgrowth and branching. In the animal model, the injected MSCs fused with the denervated myofibers, immunohistochemistry demonstrated enhanced reinnervation based on motor endplate to nerve contact, and reverse transcriptase-polymerase chain reaction confirmed stable CNTF expression at longest follow-up (4 months) in the CNTF-secreting MSC treated groups. CONCLUSIONS MSC therapy may have a future role in selectively promoting and directing laryngeal reinnervation after RLN injury.
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Affiliation(s)
- Stacey L Halum
- Department of Otolaryngology-Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.
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Pitman MJ, Weissbrod P, Roark R, Sharma S, Schaefer SD. Electromyographic and histologic evolution of the recurrent laryngeal nerve from transection and anastomosis to mature reinnervation. Laryngoscope 2011; 121:325-31. [DOI: 10.1002/lary.21290] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Halum SL, Hiatt KK, Naidu M, Sufyan AS, Clapp DW. Optimization of autologous muscle stem cell survival in the denervated hemilarynx. Laryngoscope. 2008;118:1308-1312. [PMID: 18401272 DOI: 10.1097/mlg.0b013e31816c438e] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Current treatments for vocal fold paralysis are suboptimal in that they fail to restore dynamic function. Autologous muscle stem cell (MSC) therapy is a promising potential therapy for vocal fold paralysis in that it can attenuate denervation-induced muscle atrophy and provide a vehicle for delivery of neurotrophic factors, thereby potentially selectively guiding reinnervation. The goal of this project was to characterize optimal conditions for injected autologous MSC survival in the thyroarytenoid (TA) muscle following recurrent laryngeal nerve (RLN) injury by local administration of adjuvant factors. STUDY DESIGN Animal experiment. METHODS Unilateral RLN transection and sternocleidomastoid muscle (approximately 1 g) biopsies were performed in 20 male Wistar rats. One month later, 10 autologous MSCs labeled via retroviral-enhanced green fluorescent protein (EGFP) transduction were injected into the denervated hemilarynx of each animal with one of four adjuvant therapies: cardiotoxin [(CTX) 10 M], insulin-like growth factor-1 [(IGF- 1) 100 microg/mL], ciliary neurotrophic factor [(CNTF) 50 microg/mL], or saline. Animals were euthanized 1 month later and larynges harvested, sectioned, and analyzed for MSC survival. RESULTS All specimens demonstrate extensive MSC survival, with fusion of the MSCs with the denervated myofibers. Based on mean fluorescent intensity of the laryngeal specimens, IGF-1 and CNTF had the greatest positive influence on MSC survival. Myofiber diameters demonstrated myofiber atrophy to be inversely related to MSC survival, with the least atrophy in the groups having the greatest MSC survival. CONCLUSIONS Autologous MSC therapy may be a future treatment for vocal fold paralysis. These findings support a model whereby MSCs genetically engineered to secrete CNTF and/or IGF-1 may not only promote neural regeneration, but also enhance MSC survival in an autocrine fashion.
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Heavner SB, Rubin AD, Fung K, Old M, Hogikyan ND, Feldman EL. Dysfunction of the recurrent laryngeal nerve and the potential of gene therapy. Ann Otol Rhinol Laryngol 2007; 116:441-8. [PMID: 17672247 DOI: 10.1177/000348940711600609] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Injury to the recurrent laryngeal nerve causes vocal fold paresis or paralysis resulting in poor voice quality, and possibly swallowing dysfunction and/or airway compromise. Injury can occur as part of a neurodegenerative disease process or can be due to direct nerve trauma or tumor invasion. Management depends upon symptoms, the cause and severity of injury, and the prognosis for recovery of nerve function. Surgical treatment techniques can improve symptoms, but do not restore physiologic motion. Gene therapy may be a useful adjunct to enhance nerve regeneration in the setting of neurodegenerative disease or trauma. Remote injection of viral vectors into the recurrent laryngeal nerve is the least invasive way to deliver neurotrophic factors to the nerve's cell bodies within the nucleus ambiguus, and in turn to promote nerve regeneration and enhance both nuclear and nerve survival. The purpose of this review is to discuss the potential role for gene therapy in treatment of the unsolved problem of vocal fold paralysis.
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Affiliation(s)
- S Brett Heavner
- Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor 48109-2200, USA
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Halum SL, Naidu M, Delo DM, Atala A, Hingtgen CM. Injection of autologous muscle stem cells (myoblasts) for the treatment of vocal fold paralysis: a pilot study. Laryngoscope 2007; 117:917-22. [PMID: 17473696 DOI: 10.1097/mlg.0b013e31803e8c8d] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
OBJECTIVE Autologous muscle stem cell (myoblast) therapy may be an ideal treatment for vocal fold paralysis because of its technical ease (administered by injection), its potential to restore muscular defects and dynamic function, and its autologous origin. The goal of this project was to determine whether autologous myoblast injection into the thyroarytenoid (TA) muscle after recurrent laryngeal nerve (RLN) injury could attenuate TA muscle atrophy and enhance spontaneous reinnervation. STUDY DESIGN This was an animal experiment. METHODS Unilateral RLN transection and sternocleidomastoid muscle (approximately 1 g) biopsies were performed in 16 male Wistar rats. Biopsies were used to create myoblast cultures for each animal. One month later, 10(6) autologous myoblasts labeled with fluorescent cell membrane marker (PKH26) were injected into the denervated TA of each study animal, with saline injected into controls. Animals were euthanized at 2 weeks and 2 months after myoblast injection. Outcomes included myoblast survival, TA fiber diameter and volume, and reinnervation status (motor endplate to nerve contact staining). RESULTS All denervated TA study specimens demonstrated viable myoblasts under fluorescent microscopy, with the myoblasts demonstrating fusion with the TA myofibers at 2 months. The myoblast-treated group had greater mean TA fiber diameter than denervated TA controls at 2 months (25.1 vs. 21.1 microm; P = .04) but not at 2 weeks (25.7 microm vs. 23.5 microm; P = .06). Mean TA volumes were greater in the myoblast-treated groups at both time points. Two of the animals in the myoblast-treated group demonstrated adductor motion at 2 months, whereas none of the 2 week study animals or controls recovered adduction. Reinnervation was not significantly different between the myoblast-treated groups and the denervated controls. CONCLUSIONS Autologous myoblast therapy may be a future treatment for vocal fold paralysis, with current findings demonstrating myoblast survival with attenuation of TA muscle atrophy.
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Affiliation(s)
- Stacey L Halum
- Departments of Otolaryngology-Head and Neck Surgery, Indiana University, Indianapolis, Indiana 46202, USA.
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Abstract
OBJECTIVES The surgical options for laryngeal paralysis only achieve static changes of vocal fold position. Laryngeal reinnervation procedures have had little impact on the return of dynamic laryngeal function. The development of a new treatment for laryngeal paralysis, aimed at the return of dynamic function and neurologic restoration and regeneration, is necessary. METHODS To assess the possibility of gene therapy for laryngeal paralysis aiming for the return of dynamic laryngeal function, we investigated the therapeutic effects of gene therapy using rat laryngeal paralysis models. RESULTS In a rat vagal nerve avulsion model, we transferred glial cell line-derived neurotrophic factor (GDNF) gene into the nucleus ambiguus using an adenovirus vector. Two and 4 weeks after the GDNF gene transfer, a significantly larger number of surviving motoneurons was observed. These neuroprotective effects of GDNF gene transfer were enhanced by simultaneous brain-derived neurotrophic factor gene transfer. In a rat recurrent laryngeal nerve crush model, we transferred GDNF gene into recurrent laryngeal nerve fibers after crush injury. Two and 4 weeks after GDNF gene transfer, we observed significantly faster nerve conduction velocity and better vocal fold motion recovery. CONCLUSIONS These results indicate that gene therapy could be a future treatment strategy for laryngeal paralysis. Further studies will be necessary to demonstrate the safety of the vector before clinical application.
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Affiliation(s)
- Akihiro Shiotani
- Department of Otolaryngology-Head and Neck Surgery, National Defense Medical College, Saitama, Japan
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Thomas LB, Harrison AL, Stemple JC. Aging thyroarytenoid and limb skeletal muscle: lessons in contrast. J Voice 2008; 22:430-50. [PMID: 17241767 DOI: 10.1016/j.jvoice.2006.11.006] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2006] [Accepted: 11/29/2006] [Indexed: 01/07/2023]
Abstract
Voice production is vital throughout life because it allows for the communication of basic needs as well as the pursuit and enjoyment of social encounters. Unfortunately, for many older individuals the ability to produce voice is altered. Structural and functional declines in the neuromuscular system occur with aging and likely contribute to the modification of voice. One specific target of the aging process is the thyroarytenoid (TA) muscle, the primary muscle of voice production. The objectives of this overview article are to (1) share current findings related to the aging of limb skeletal muscle, (2) identify age-related morphological and physiological features of TA muscle, (3) compare and contrast age-related changes in TA with those in limb skeletal muscle, and (4) describe therapies for reversing sarcopenia in limb muscle and consider the applicability of these therapies for addressing vocal fold atrophy and age-related voice changes. The article shares current knowledge from the basic sciences related to skeletal muscle aging and compares/contrasts typical muscle aging to TA aging. Current evidence suggests that (1) the TA muscle undergoes notable remodeling with age, (2) aging of the TA is multifactorial, resulting from a myriad of neurologic, metabolic, and hormonal changes, many of which are distinct from the age-related processes of typical limb skeletal muscle, (3) investigation of the aging of the TA and its role in the aging of voice is in its infancy, and (4) potential behavioral and nonbehavioral therapies for reversing aging of the TA must be further examined.
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Abstract
PURPOSE Proteomic methodologies offer promise in elucidating the systemwide cellular and molecular processes that characterize normal and diseased thyroarytenoid (TA) muscle. This study examined methodological issues central to the application of 2-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis (2D SDS-PAGE) to the study of the TA muscle proteome using a rat model. METHOD 2D SDS-PAGE was performed using 4 chemically skinned rat TA muscle samples. Gel images were analyzed and compared. Protein spot detection and matching were performed using computational image analysis algorithms only and computational image analysis followed by visual inspection and manual error correction. A synthetic master gel, constructed to control for uninteresting biological variation and technical artifact due to differences in protein loading and staining, was evaluated against its constituent gels. RESULTS Manual error correction resulted in a consistent increase in the number of protein spots detected (between 5.8% and 40.9%) and matched (from 25.8% to 70.8%) across all gels. Sensitivity and specificity of the automatic (computational) spot detection procedure, evaluated against the manual correction procedure, were 74.1% and 97.9%, respectively. Evaluation of protein quantitation parameter values revealed statistically significant differences (p < .0001) in optical density, area, and volume for matched protein spots across gels. The synthetic master gel successfully compensated for these intergel differences. CONCLUSIONS Valid and reliable proteomic data are dependant on well-controlled manageable variability and well-defined unmanageable variability. Manual correction of spot detection and matching errors and the use of a synthetic master gel appear to be useful strategies in addressing these issues. With these issues accounted for, 2D SDS-PAGE may be applied to quantitative experimental comparisons of normal and disease conditions affecting voice, speech, and swallowing function.
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Affiliation(s)
- Nathan V Welham
- Department of Physiology, University of Wisconsin--Madison, 53706, USA
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Abstract
Direct repair of the recurrent laryngeal nerve (RLN) results in synkinesis and compromised laryngeal function. We have therefore developed a pig model to investigate whether anastomosis of the phrenic nerve with the abductor branch of the RLN leads to specific reinnervation of abductor muscles. Expression of myosin heavy chain protein (MyHC), a marker of appropriate reinnervation, was determined in the posterior cricoarytenoid (PCA) abductor and thyroarytenoid (TA) adductor muscles following nerve injury and repair. The denervated PCA muscle exhibited decreased levels of the fast-type MyHC isoforms IIA and IIB, and increased slow-type MyHC expression. Similarly, there was a fall in type IIB levels in the denervated TA muscle but increases in both IIA and slow MyHC. Four months after repair, the MyHC expression in the PCA was near normal, suggesting that our model reduces the risk of synkinesis and ensures the accurate muscle reinnervation required for full functional recovery.
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Affiliation(s)
- Paul J Kingham
- Blond McIndoe Research Laboratories, Plastic and Reconstructive Surgery Research, Stopford Building, University of Manchester, Oxford Road, Manchester M13 9PT, UK.
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Abstract
OBJECTIVES The ultimate goal of this study is to improve the efficiency of gene transfer in mammalian muscle by developing targeted adenoviral vectors. Altering the tropism of viral vectors to recognize tissue specific antigens is one method to achieve this goal. This approach requires identification of cell-surface receptors and the insertion of target peptide sequences into the adenoviral fiber protein. In this study, phage biopanning was performed on cultured rat skeletal and laryngeal muscle to identify cell-surface receptors. STUDY DESIGN In vitro cell culture and in vivo animal model. METHODS M-13 Phage biopanning was used for muscle cell-surface receptor analysis on cultured rat skeletal and laryngeal muscle. Nonbinding and binding phage to cultured skeletal and laryngeal muscle were screened for muscle specific surface peptides. In vivo studies were then performed using muscle specific phage. RESULTS Skeletal muscle specific binding by the YASTNPM phage was observed by in vivo immunostaining. Phage titering demonstrated a 10(9)-fold increase in skeletal muscle binding compared with nontarget tissue. A peptide sequence (NPSQVKH) specific for laryngeal muscle yielded a 10(7)-fold increase in laryngeal muscle phage titer compared with nontarget tissue. CONCLUSIONS These results identify muscle cell-surface receptors that may be used as potential targets for genetic modification of adenovirus tropism. Moreover, phage specificity for skeletal and laryngeal muscle indicates specific muscle groups may be targeted.
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Affiliation(s)
- Paul W Flint
- Department of Otolaryngology-Head and Neck Surgery Johns Hopkins University, Baltimore, Maryland, USA.
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