Hayato Komobuchi

Insulin-like growth factor 1 treatment via hydrogels rescues cochlear hair cells from ischemic injury

This study was designed to investigate the protective effects of recombinant human insulin-like growth factor 1 (rhIGF1), applied locally via a hydrogel, against ischemic damage of the cochleae in gerbils. A hydrogel was immersed in rhIGF1 or saline and was applied on the round window membrane 30 min after the ischemia. Local rhIGF1 treatment significantly reduced the elevation of auditory brain responses thresholds at a frequency of 8 kHz on days 1, 4, and 7 after ischemia. A histological analysis revealed increased survival of inner hair cells in the animals treated with rhIGF1 via the hydrogel 7 days after ischemia. These findings showed that local rhIGF1 application using a hydrogel has the potential to protect the cochleae from ischemic injury.

Basic fibroblast growth factor combined with biodegradable hydrogel promotes healing of facial nerve after compression injury: An experimental study

Conclusion. Topical application of basic fibroblast growth factor (bFGF) hydrogel facilitates faster healing from traumatic facial paralysis due to continuous release of bFGF. Objectives. bFGF is considered a potent agent to facilitate recovery from neuronal damage; however, exogenously applied bFGF does not work well because of its short acting time. To enhance the effects in vivo, we developed a new drug delivery system by embedding bFGF in a gelatin hydrogel that degrades slowly. In this study, the effects of bFGF-hydrogel on traumatic facial nerve paralysis were investigated in guinea pigs. Methods. The intratemporal facial nerve was exposed and clamped at the vertical portion using micro needle forceps. The animals were then subjected to one of the following three procedures: group A, no further treatment; group B, one-shot application of bFGF to the nerve; and group C, application of bFGF-hydrogel instead. Six weeks later, facial nerve functions were evaluated by three test batteries: observation of facial movements, electrophysiological testing, and histological study. Results. The results for groups A and B were similar in the three tests, indicating that one-shot application of bFGF did not benefit facial nerve recovery. In contrast, group C achieved better results in all tests.

Resection of peripheral branches of the posterior nasal nerve compared to conventional posterior neurectomy in severe allergic rhinitis

OBJECTIVE Transnasal resection of the posterior nasal nerve (TRPN) is the surgical procedure for drug therapy-resistant, intractable allergic rhinitis (AR). Submucous inferior turbinectomy also improves nasal symptoms in severe AR. Surgical injury to this peripheral nerve fibre may be the major cause of the decrease in allergic symptoms. During submucous turbinectomy, we have identified the peripheral branches of the posterior nasal nerve in the inferior turbinate and resected them (SRPN). The aim of this study was to evaluate the therapeutic effects of turbinoplasty with SRPN in severe AR. METHODS Improvements in subjective symptoms were compared between 13 patients who underwent SRPN with turbinoplasty (Group 1) and 11 who underwent TRPN combined with turbinoplasty and SRPN (Group 2) by retrospective chart review. Pre- and postoperative sneezing, rhinorrhea, and nasal obstruction were evaluated with questionnaires. Postoperative complications and drug therapy before and after surgery were investigated. RESULTS All symptoms improved postoperatively in both groups, with no significant differences in the improvements in nasal symptom scores between the groups. CONCLUSIONS SRPN combined with submucosal turbinectomy was shown to be a safe, useful, and efficient approach to patients with AR unresponsive to medical therapy. Although this is a short-term study, the results of this study suggest that SRPN represents one of the treatment options for intractable AR.

Facial nerve decompression surgery using bFGF-impregnated biodegradable gelatin hydrogel in patients with Bell palsy.

Objective. Basic fibroblast growth factor (bFGF) promotes the regeneration of denervated nerves. The aim of this study was to evaluate the regeneration-facilitating effects of novel facial nerve decompression surgery using bFGF in a gelatin hydrogel in patients with severe Bell palsy. Study Design. Prospective clinical study. Setting. Tertiary referral center. Subjects and Methods. Twenty patients with Bell palsy after more than 2 weeks following the onset of severe paralysis were treated with the new procedure. The facial nerve was decompressed between tympanic and mastoid segments via the mastoid. A bFGF-impregnated biodegradable gelatin hydrogel was placed around the exposed nerve. Regeneration of the facial nerve was evaluated by the House-Brackmann (H-B) grading system. The outcomes were compared with the authors’ previous study, which reported outcomes of the patients who underwent conventional decompression surgery (n = 58) or conservative treatment (n = 43). Results. The complete recovery (H-B grade 1) rate of the novel surgery (75.0%) was significantly better than the rate of conventional surgery (44.8%) and conservative treatment (23.3%). Every patient in the novel decompression surgery group improved to H-B grade 2 or better even when undergone between 31 and 99 days after onset. Conclusion. Advantages of this decompression surgery are low risk of complications and long effective period after onset of the paralysis. To the authors’ knowledge, this is the first clinical report of the efficacy of bFGF using a new drug delivery system in patients with severe Bell palsy.

Myogenin expression in facial muscle following damage to the facial nerve

Abstract Conclusion: Gene analysis of facial muscle may be a promising way to detect denervation of facial muscle, helping to determine the prognosis of a facial palsy early in its progression. Objectives: In the treatment of intratemporal facial palsy, early diagnosis of neural damage is important in deciding about therapeutic modalities. In this study, we investigated the relationship between the severity of facial palsy and the level of myogenin expressed in the facial muscle. Methods: The animals were divided into two groups, depending on whether the facial nerve was resected or compressed. Expression of myogenin mRNAwas examined using real-time PCR and in situ hybridization of the facial muscle following the nerve damage. Results: Increased expression of myogenin was observed in the nerve resection group, while no such increase was seen in the nerve compression group. In situ hybridization indicated that myogenin was expressed exclusively in satellite cells around the denervated muscle fibers.