Yo Kishimoto

Chronic vocal fold scar restoration with hepatocyte growth factor hydrogel

Therapeutic challenges exist in the management of vocal fold scarring. We have previously demonstrated the therapeutic potential of hepatocyte growth factor (HGF) in the management of acute phase vocal fold scarring using a novel hydrogel‐based HGF drug delivery system (DDS). However, the effect of HGF on matured vocal fold scarring remains unclear. The current study aims to investigate the effect of HGF‐DDS on chronic vocal fold scarring using a canine model.

Regeneration of aged vocal fold: first human case treated with fibroblast growth factor.

BACKGROUND/OBJECTIVES Aged vocal folds are characterized by atrophy of the mucosa, which caused dysphonia and is difficult to treat. We have revealed a therapeutic potential of basic fibroblast growth factor (bFGF) for tissue regeneration of the aged vocal fold. We report here the first human case that has been treated with bFGF. STUDY DESIGN Institutional review board-approved clinical human trial. METHODS A 63-year-old male with atrophied vocal folds was treated by local injection of 10 mug of bFGF into the left vocal fold under topical anesthesia. The effects of the injection were examined after 1 to 3 months by videostroboscopy, acoustic, and aerodynamic measurements. RESULTS The atrophy of the vocal fold was improved at 1 week after the injection, and glottic gap disappeared. Aerodynamic and acoustic parameters also showed remarkable improvement. These positive effects were maintained up to 3 months. CONCLUSIONS The first case with aged vocal folds treated with bFGF administration was presented. The results are encouraging, suggesting therapeutic effects of bFGF for atrophied vocal folds in human.

Treatment of acute vocal fold scar with local injection of basic fibroblast growth factor: a canine study

Abstract Conclusions: Results of the current study revealed improved phonation threshold pressure (PTP), normalized mucosal wave amplitude (NMWA), and less contraction of the lamina propria in injured larynges treated with basic fibroblast growth factor (bFGF). Objectives: We investigated the effects of local injection of bFGF for treatment of acute vocal fold injury in a canine model. Methods: Vocal folds of eight beagles were unilaterally injured by removal of the mucosa under direct laryngoscopy. Four beagles received local injections of bFGF delivered to the scarred vocal fold at 1 month after injury. The remaining four beagles received local injections of saline and served as a sham-treatment group. Larynges were harvested 5 months after treatment and excised larynx experiments were performed to measure PTP, NMWA, and normalized glottal gap (NGG). Histologic staining was performed to evaluate structural changes of the extracellular matrix. Results: Excised larynx measurements revealed significantly lower PTP and increased NMWA in bFGF-treated vocal fold. Elastica Van Gieson staining revealed less contraction of the bFGF-treated vocal fold. Histologic measurements revealed that the thickness of the lamina propria was significantly greater in the bFGF-treated vocal fold. Alcian blue staining revealed improved restoration of hyaluronic acid in the bFGF-treated vocal fold.

Clinical trial of regeneration of aged vocal folds with growth factor therapy

Aged vocal folds are characterized by atrophy of the mucosa, which causes mucosal wave deficiency and glottal insufficiency. This clinical trial examined the regenerative effects and safety considerations of basic fibroblast growth factor (bFGF) on restoration of aged vocal folds.

TGF-β3 modulates the inflammatory environment and reduces scar formation following vocal fold mucosal injury in rats.

Transforming growth factor (TGF)-β1 and TGF-β3 have been reported to exert differential effects on wound healing, and possibly even account for tissue-specific differences in scar formation. Scarring is particularly detrimental in the vocal fold mucosa (VFM), where destruction of the native extracellular matrix causes irreparable biomechanical changes and voice impairment. Here, in a series of in vitro and in vivo experiments, we identified differences in TGF-β1 and TGF-β3 transcription and immunolocalization to various cell subpopulations in naïve and injured rat VFM, compared with oral mucosa (which undergoes rapid healing with minimal scar) and skin (which typically heals with scar). Treatment of cultured human vocal fold fibroblasts with TGF-β3 resulted in less potent induction of profibrotic gene transcription, extracellular matrix synthesis and fibroblast-myofibroblast differentiation, compared with treatment with TGF-β1 and TGF-β2. Finally, delivery of exogenous TGF-β3 to rat VFM during the acute injury phase modulated the early inflammatory environment and reduced eventual scar formation. These experiments show that the TGF-β isoforms have distinct roles in VFM maintenance and repair, and that TGF-β3 redirects wound healing to improve VFM scar outcomes in vivo.

Implantation of an Atelocollagen Sheet for the Treatment of Vocal Fold Scarring and Sulcus Vocalis

Objectives: The management of vocal fold scarring and sulcus vocalis is challenging. These disorders are thought to be fibroplastic anomalies in the cover portion of the vocal fold that cause deterioration of the vibratory properties of the vocal fold mucosa. Histologic studies have revealed disorganization of extracellular matrix that needs to be addressed in the treatment of scarred vocal folds. Replacement of scar tissues with an appropriate implant may lead to regeneration of the vocal fold mucosa and its tissue properties. This retrospective case study examined the feasibility of using an atelocollagen sheet as a regenerative implant. Methods: Six patients with a post-cordectomy scar or sulcus vocalis underwent implantation of an atelocollagen sheet into the lamina propria of the vocal folds. The procedure consisted of elevation of a microflap, dissection and removal of scar tissue, implantation of the material, and wound closure. Vocal function was evaluated before and after surgery by stroboscopic examination and by aerodynamic and acoustic analyses. Results: The postoperative changes of aerodynamic and acoustic parameters varied among patients; however, gradual improvement was seen in most cases over a year. Stroboscopic findings also revealed gradual improvement of vibratory properties in most cases. Conclusions: Implantation of an atelocollagen sheet may have restorative effects on vocal fold scarring and sulcus vocalis in terms of tissue properties and function of the mucosa.

Endoscopic KTP Laser Photocoagulation Therapy for Pharyngolaryngeal Venous Malformations in Adults

Objectives: Venous malformations are benign lesions with thin, fragile mucosa overlying a vascular stroma. Vascular anomalies often manifest as subglottic lesions in infants, but venous malformations in adults are rare in the pharyngolaryngeal region. The treatments include open and endoscopic surgery; intraoperative bleeding is often troublesome. Angiolytic lasers such as the potassium titanyl phosphate (KTP) laser enable photocoagulation for such hemorrhagic lesions without bleeding; we report findings from a series of adult patients. Methods: Seven adults were treated with a KTP laser set at a low power of 1.5 W in continuous mode. Photocoagulation was easily performed for shallow lesions; however, laser irradiation of bulky venous malformations resulted only in surface photocoagulation. In such cases, the crust remaining after photocoagulation was removed, and laser energy was repeatedly delivered until no remnant lesion was seen. An office procedure using flexible endoscopy was performed under topical anesthesia for 1 patient with a limited lesion. Results: The lesions were well controlled in all cases without major complications. A patient with a large obstructing lesion had a relapse. Because the recurrent lesion is small and the patient does not desire additional treatment at this time, she is being observed carefully. Conclusions: Photocoagulation using the KTP laser is a feasible and relatively safe treatment for pharyngolaryngeal venous malformations in adults.

Effects of basic fibroblast growth factor on rat vocal fold fibroblasts.

Objectives The overarching goal of this line of research is to translate basic fibroblast growth factor (bFGF) treatment for vocal fold scarring into practical clinical use. In a previous canine investigation, we demonstrated that bFGF improves phonation threshold pressure, mucosal wave amplitude, and histologic measures in vocal folds treated after injury. In the present study, we studied the effects of bFGF on gene expression of the extracellular matrix and growth factors in rat vocal fold fibroblasts. Methods Fibroblasts harvested from the vocal folds of 5 rats were treated with 3 concentrations of bFGF (0, 10, and 100 ng/mL). The fibroblasts were collected at 24 hours and 72 hours after bFGF administration. Quantitative polymerase chain reaction was then used to investigate the gene expression of the investigated growth factors and extracellular matrices. Results The results revealed significantly down-regulated expression of procollagen I and significantly up-regulated expression of hyaluronic acid synthase (HAS) 2 and fibronectin in fibroblasts treated with bFGF. The administration of bFGF also resulted in the up-regulation of bFGF and hepatocyte growth factor (HGF). No changes in the expression of HAS-1, tropoelastin, or procollagen III were observed between the treatment and control conditions. Conclusions Treatment with bFGF induces the down-regulation of procollagen I and the up-regulation of HAS-2 in vocal fold fibroblast cell cultures. These gene expression alterations to key mediators of the wound healing process may translate into potential benefits in the remediation of vocal fold injury. The up-regulation of HGF, an antifibrotic effector molecule, may demonstrate additional benefits by optimizing the wound healing environment and by accelerating the wound repair cascade. These findings may provide fuel for additional discoveries into the development of growth factor therapy for the treatment of vocal fold scar.

Multidimensional Analysis on the Effect of Vocal Function Exercises on Aged Vocal Fold Atrophy

OBJECTIVES Age-related voice change is characterized as weak, harsh, and breathy. These changes are caused by histologic alteration of the lamina propria of the vocal fold mucosa as well as atrophy of the thyroarytenoid muscle. Several therapeutic strategies involving laryngeal framework surgery and injection laryngoplasty have been tried, but effects have been limited. Vocal function exercises (VFE) have been used to treat age-related vocal fold atrophy although the effectiveness has been shown with limited analysis. The present study aims to determine the effectiveness of VFE for the treatment of aged atrophy using multidimensional analysis. STUDY DESIGN This is a retrospective study. METHODS Sixteen patients with vocal fold atrophy aged 65-81 years underwent voice therapy using VFE. Six patients with vocal fold atrophy aged 65-85 years were involved as a historical control group. The grade, roughness, breathiness, asthenia, strain (GRBAS) scale, stroboscopic examinations, aerodynamic assessment, acoustic analysis, and Voice Handicap Index-10 (VHI-10) were performed before and after VFE. Normalized mucosal wave amplitude (NMWA), normalized glottal gap (NGG), and bowing index (BI) were measured by image analysis during stroboscopic examinations. RESULTS After VFE, significant improvements were shown in GRBAS, maximum phonation time, jitter, NMWA, NGG, and VHI-10 although BI has not changed significantly. There were no significant improvements in the historical control. CONCLUSIONS The data suggest that VFE produces significant improvement in subjective, objective, and patient self-evaluation and deserves further attention as a treatment for aged atrophy of the vocal fold. It was also suggested that VFE does not improve the vocal fold bowing but may improve muscular function during voicing.

Atelocollagen Sponge as a Stem Cell Implantation Scaffold for the Treatment of Scarred Vocal Folds

Objectives: Treatment of vocal fold scarring remains a therapeutic challenge. Our group previously reported the efficacy of treating injured vocal folds by implantation of bone marrow—derived stromal cells containing mesenchymal stem cells. Appropriate scaffolding is necessary for the stem cell implant to achieve optimal results. Terudermis is an atelocollagen sponge derived from calf dermis. It has large pores that permit cellular entry and is degraded in vivo. These characteristics suggest that this material may be a good candidate for use as scaffolding for implantation of cells. The present in vitro study investigated the feasibility of using Terudermis as such a scaffold. Methods: Bone marrow—derived stromal cells were obtained from GFP (green fluorescent protein) mouse femurs. The cells were seeded into Terudermis and incubated for 5 days. Their survival, proliferation, and expression of extracellular matrix were examined. Results: Bone marrow—derived stromal cells adhered to Terudermis and underwent significant proliferation. Immunohistochemical examination demonstrated that adherent cells were positive for expression of vimentin, desmin, fibronectin, and fsp1 and negative for beta III tubulin. These findings indicate that these cells were mesodermal cells and attached to the atelocollagen fibers biologically. Conclusions: The data suggest that Terudermis may have potential as stem cell implantation scaffolding for the treatment of scarred vocal folds.