Injection Laryngoplasty with Human Adipose Tissue Derived Extracellular Matrix and Methylcellulose Hydrogels

Abstract

Objective: To introduce a mixture soluble extracellular matrix (sECM) and methylcellulose (MC) hydrogels as an injection laryngoplasty material and present the preliminary animal study focusing on a bio-suitability of sECM/MC hydrogels Subjects and Methods: sECM was fabricated from human adipose tissue which was obtained by a liposuction technique. After removing blood and oil components from adipose tissue, the tissue was homogenized, centrifuged and lyophilized. sECM/MC solution was prepared by a mixture of lyophilized sECM and MC solution that was obtained by dispersion technique. Unilateral vocal fold palsy was made to twenty New Zealand white rabbits by recurrent laryngeal nerve section and five rabbits without procedure were used as a normal group. Twenty animals of vocal fold palsy were randomly divided into 4 groups. Group 1-3 received sECM/MC injection at paralyzed vocal fold and sacrificed 1, 4 and 8 weeks after injection, respectively. Group 4 was not injected and used as a control. Laryngoscopic exams were performed at 1, 4 and 8 weeks after injection laryngopalsty

then vocal fold vibration was evaluated for functional analysis by high speed video recording and histologic study was performed in each groups. Results: All animals except one rabbit survived until the scheduled period. Laryngoscopic analysis showed that sECM/MC maintained its volume through 8 weeks after injection. Histologic studies also revealed the augmentation effect in paralyzed vocal fold without significant inflammatory response. There were increased number of collagen fibers and fatty granules at the injection site without significant inflammation or fibrosis. On functional analysis, high speed camera examination revealed regular and symmetric contact of vocal fold mucosa without a distorted movement by injected sECM/MC in experimental group. Also asymmetric vocal fold movement was improved compared with the control group. Conclusion: In the paralyzed vocal fold, sECM/MC hydrogels showed a good bio-compatibility and effective augmentation results histologically and functionally. These results indicate that the sECM/MC hydrogel can enhance vocal function in paralyzed vocal folds without early resorption and has potential as a promising material for injection laryngoplasty for stable vocal fold augmentation which can overcome the shortcomings of autologous fat such as unpredictable duration and morbidity associated with the fat harvest.