Hylan B Gel Restores Structure and Function to Laser-Ablated Canine Vocal Folds
Division of Head and Neck Surgery, University of California-Los Angeles Medical Center, Los Angeles, California 90095, USA. The Annals of otology, rhinology, and laryngology
(Impact Factor: 1.09).
10/2008; 117(9):703-7. DOI: 10.1177/000348940811700913
We evaluated cross-linked hyaluronic acid (hylan B gel) as a scaffold for tissue regeneration and mucosal wave restoration in carbon dioxide laser-ablated canine vocal folds.
Five beagles underwent stroboscopy before ablation of the left vocal fold with a carbon dioxide laser. Four weeks later, stroboscopy was repeated before and after submucosal injection of hylan B gel into the left vocal fold of 4 animals and of saline solution in 1 animal. Stroboscopy was repeated 12 weeks later, and histologic analysis was performed.
Four weeks after laser ablation, all animals had soft tissue defects and absence of mucosal waves. Hylan B injection restored mucosal waves, and saline injection did not. Twelve weeks after injection, hylan B-injected larynges had tissue regeneration and mucosal waves, and the saline-injected larynx had neither. Histology showed regenerated lamina propria with residual foci of hylan B in the hylan B-injected larynges and dense submucosal scar in the saline-injected animal.
Submucosal hylan B gel injection in laser-ablated canine vocal folds restored tissue volume and mucosal waves and facilitated functional tissue regeneration over 12 weeks. Hylan B gel may have utility as a soft tissue scaffold for rehabilitation of phonatory function in vocal folds with lamina propria defects.
Available from: Linqing Li
- "Mechanical stress from excessive phonation, deleterious environmental factors, and pathological conditions can disrupt the natural pliability of the vocal folds, resulting in a wide spectrum of vocal disorders and causing significant implications for individual health, social productivity, and occupational function (Zeitels et al., 2002). Surgical approaches for vocal fold augmentation or mucosal reconstruction have employed a variety of either injectable or implantable synthetic and biological materials (Hallén et al., 2001; Hirano et al., 2008; Jahan-Parwar et al., 2008; Kwon and Lee, 2008; Kishirnoto et al., 2009; Kutty and Webb, 2009b). Although improvements in voice production have been reported, limitations such as implant migration, foreign body reaction, stiffness, immunological consequences, and the need of multi-stage procedures largely have prevented restoration of functional vocal fold tissue. "
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ABSTRACT: The outstanding high-frequency properties of emerging resilin-like polypeptides (RLPs) have motivated their development for vocal fold tissue regeneration and other applications. Recombinant RLP hydrogels show efficient gelation, tunable mechanical properties, and display excellent extensibility, but little has been reported about their transient mechanical properties. In this manuscript, we describe the transient mechanical behavior of new RLP hydrogels investigated via both sinusoidal oscillatory shear deformation and uniaxial tensile testing. Oscillatory stress relaxation and creep experiments confirm that RLP-based hydrogels display significantly reduced stress relaxation and improved strain recovery compared to PEG-based control hydrogels. Uniaxial tensile testing confirms the negligible hysteresis, reversible elasticity and superior resilience (up to 98%) of hydrated RLP hydrogels, with Young's modulus values that compare favorably with those previously reported for resilin and that mimic the tensile properties of the vocal fold ligament at low strain (<15%). These studies expand our understanding of the properties of these RLP materials under a variety of conditions, and confirm the unique applicability, for mechanically demanding tissue engineering applications, of a range of RLP hydrogels.
Frontiers in Chemistry 04/2014; 2:21. DOI:10.3389/fchem.2014.00021
Available from: Patricia Zuk
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ABSTRACT: One potential treatment option for severe vocal fold scarring is to replace the vocal fold cover layer with a tissue-engineered structure containing autologous cells. As a first step toward that goal, we sought to develop a three-dimensional cell-populated matrix resembling the vocal fold layers of lamina propria and epithelium.
Basic science investigation.
Adipose-derived stem cells were cultured in fibrin hydrogels with various growth factors. At the end of the culture period, matrices were sectioned and labeled with immunomarkers to identify cell phenotype.
Adipose-derived stem cells survived, attached, and populated three-dimensional fibrin matrices. Under select conditions, a superficial layer of cells expressing epithelial marker proteins overlay a deeper mesenchymal cell layer.
A three-dimensional structure of fibrin and adipose-derived stem cells was created as a prototype vocal fold replacement. Two segregated cell phenotypes occurred, producing a bilayered structure resembling epithelium over lamina propria. This preliminary work demonstrates the feasibility of tissue engineering to produce structures for vocal fold replacement.
The Laryngoscope 01/2009; 120(1):125-31. DOI:10.1002/lary.20719 · 2.14 Impact Factor
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ABSTRACT: To review the recent literature on the etiology and pathophysiology of vocal fold nodules in adults.
Research regarding the etiology of vocal nodules over the past 2 years supports previous thinking regarding the central role of voice misuse, overuse, and phonatory trauma. Advanced modeling techniques have helped elucidate mechanisms by which this may occur such as vibration-induced rise in capillary pressures and varying fluid dynamics in the layered vocal fold structure. Contributory roles of personality traits, reflux, and allergy have also been hypothesized.
Current research supports long-held beliefs that phonatory trauma is a central cause of vocal fold nodule formation. Innovative basic science research has unraveled mechanisms of traumatic damage and clinical research continues to identify crucial lifestyle behavior and contributing comorbid conditions that play a role in the pathogenesis of vocal fold nodules. The multifactorial etiology of vocal fold nodules requires a comprehensive history to identify contributing factors and a multidisciplinary approach to optimize treatment outcome.
Current opinion in otolaryngology & head and neck surgery 09/2009; 17(6):420-3. DOI:10.1097/MOO.0b013e328331a7f8 · 1.84 Impact Factor
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