Regeneration of Mastoid Air Cells in Vivo Using Autologous Cortical Bone

Purpose: This was a preliminary study to assess surgical construction and regeneration of mastoid air cells in the treatment of cholesteatoma. Methods: Two-stage tympanoplasty with mastoidectomy was performed in four cases of unilateral cholesteatoma with sclerotic mastoid. During the first-stage operation, small fragments of autologous cortical bone were inserted into the cavity after mastoidectomy to form a honeycomb-like structure. Reconstruction of the lateral wall of the mastoid cavity was performed using the mastoid cortical bony plate. Pre- and postoperative mastoid volume was evaluated by three-dimensional reconstruction based on high-resolution computed tomography (HR-CT) images. Results: HR-CT images after the first-stage operation showed that mastoid volume had increased in all subjects. Macroscopic inspection during the second-stage operation revealed that the honeycomb-like structure made of bony fragments and covered by thin mucosa in the mastoid cavity was stable, with no evidence of effusion or granulation tissue. No retraction of the eardrum, middle ear effusion or recurrence of cholesteatoma was observed, and the hearing level on a pure-tone audiogram was improved in any subject 60 - 94 months after the second-stage operation. Conclusion: Surgical construction and regeneration of mastoid air cells using autologous cortical bone can be useful in treatment of cholesteatoma with arrested mastoid pneumatization

Histologic Characterization of Human Scarred Vocal Folds

Vocal fold scarring remains a significant problem. Although several animal models have been developed to improve our understanding of the histopathology, the histologic features of scarred human vocal folds have rarely been reported. The present case studies aimed to define the histologic changes of scarred human vocal folds caused by cordectomy or cordotomy. Ten patients with the scarred vocal folds were involved in this study. Nine patients with early glottic cancer underwent endoscopic cordectomy, and one patient underwent superficial cordotomy for idiopathic scar. The postcordectomy or cordotomy scar was biopsied or resected 3-13 months after the original procedure. After confirming absence of any tumor in cancer patients, the remaining specimens were used in the present study. Histologic examination investigated deposition of extracellular matrix (ECM) including collagen, elastin, hyaluronic acid (HA), fibronectin, and decorin in the lamina propria of the scarred vocal folds. There was a wide range of variation in the deposition of ECM in scarred vocal folds. Excessive and disorganized collagen deposition was observed in most cases that had undergone deep resection of the lamina propria, whereas deposition of collagen was mild and well organized after superficial resection. Decorin was retained in all cases after superficial cordectomy or cordotomy, but varied after deep resection. Deposition of elastin, HA, and fibronectin varied regardless of depth of injury. Histology of scarred vocal folds may vary with degree of injury and individual healing mechanism

Adipose-derived stem cells versus bone marrow-derived stem cells for vocal fold regeneration.

[Objectives/Hypothesis]Vocal fold scarring presents therapeutic challenges. Recently, cell therapy with mesenchymal stromal cells has become a promising approach. The aim of this study was to compare the therapeutic potential of adipose-derived stem cells (ASC) with bone marrow-derived stem cells (BMSC) for vocal fold regeneration. [Study Design]Prospective animal experiments with controls. [Methods]The vocal folds of Sprague-Dawley rats were unilaterally injured. Two months after injury, rats were treated with a local injection of ASC (ASC group), BMSC (BMSC group), or saline (sham-treated group). The GFP-labeled ASC and BMSC were extracted from CAG-EGFP rats. Larynges were harvested for histological and immunohistochemical examinations 1 and 3 months posttransplantation and for quantitative real-time polymerase chain reaction (PCR) 1 month posttransplantation. [Results] After 1 month, no surviving cells from the transplant were detected. Histological examination showed significantly increased hyaluronic acid (HA) and decreased dense collagen deposition in both ASC and BMSC groups compared to shams 1 and 3 months after treatment. Real-time PCR revealed that hyaluronan synthase 1 (Has1) and Has2 were upregulated in only the ASC group compared with the sham-treated group. Fibroblast growth factor 2 (basic) (Fgf2), hepatocyte growth factor (Hgf) and Has3 were upregulated in both cell transplantation groups. ASC seemed to upregulate Hgf more than did BMSC. [Conclusions]The regenerative effects of ASC and BMSC transplantation were found to be similar for the restoration. It is suggested that ASC might have more potential because of better recovery of HA, a superior antifibrotic effect, and the upregulation of Hgf

Diagnosing Middle Ear Malformation by Pure-Tone Audiometry Using a Three-Dimensional Finite Element Model: A Case-Control Study

Background: Hearing loss caused by middle ear malformations is treated by tympanoplasty to reconstruct the acoustic conduction system. The mobility of the ossicles plays a crucial role in postoperative success. However, identifying the location of ossicular malformation based solely on preoperative audiograms is challenging due to the complex relationship between fixation location, deformity levels, and ossicular mobility. Methods: Middle ear finite element models for simulating ossicular malformations were created, and the results were compared with the actual preoperative audiograms. Results: This approach objectively diagnosed ossicular fixation and disarticulation, bypassing traditional criteria reliant on physician examination or imaging. Conclusion: This study suggests that future research should focus on developing a diagnostic framework utilizing large-scale data

Effect of AST on age-associated changes of vocal folds in a rat model.

[Objectives/Hypothesis]Reactive oxygen species (ROS) are associated with aging. Astaxanthin (AST) is a strong antioxidant and has been reported to prevent various ROS-induced diseases. In the current study, we investigated the effect of AST on age-associated histological and mRNA changes of vocal folds. [Study Design]Prospective animal experiment with control. [Methods]Six-month-old Sprague-Dawley rats were fed on a normal powder diet with 0.01% (w/w) AST (aged AST-treated group) or without AST (aged sham-treated group). After 12 months of feeding, the larynges were harvested for histology, immunohistochemical detection of 4-hydroxy-2-nonenal (4-HNE), and quantitative real-time polymerase chain reaction for basic fibroblast growth factor (bFGF) and hepatocyte growth factor (HGF). Thirteen-week-old rats were used as a young control group (young group). [Results]The expression of 4-HNE, an oxidative stress marker, significantly increased in the two aged groups compared with the young group. Histological examination showed that the deposition of hyaluronic acid in the lamina propria (LP) was significantly reduced in the aged sham-treated group compared with the young group, but no significant difference was observed between the aged AST-treated group and the young group. There were no significant differences in the mRNA expression of bFGF and HGF between the aged AST-treated group and the young group, although the expression of these genes was significantly reduced in the aged sham-treated group as compared with the young group. [Conclusions]These results suggest that AST has the potential to attenuate age-associated changes of vocal folds