Seok Won Park

Inhibitory effect of caffeic acid phenethyl ester (CAPE) on LPS-induced inflammation of human middle ear epithelial cells

Conclusions. The results suggest that the anti-inflammatory effect of caffeic acid phenethyl ester (CAPE) is due to its inhibition of tumor necrosis factor (TNF)-α expression and interleukin (IL)-8 production. The anti-inflammatory effect of CAPE is possibly through the inhibition of nuclear factor (NF)-κB via the suppression of inhibitor-κB-α (IκB-α) degradation. Objectives. CAPE is a biologically active component of propolis, a resinous material obtained from bee hives, which originates from conifer bark. The effect of CAPE on lipopolysaccharide (LPS)-induced inflammatory reactions is not known. The aim of this study was to evaluate the anti-inflammatory effect of CAPE on cultured human middle ear epithelial cells (HMEECs). Materials and methods. The effect of CAPE on LPS-induced TNF-α expression was evaluated in HMEECs by real-time reverse transcription polymerase chain reaction (RT-PCR). LPS-induced IL-8 production was determined by enzyme-linked immunosorbent assay (ELISA), and LPS-induced IκB-α degradation was followed by Western blot analysis. Results. CAPE significantly inhibited LPS-induced up-regulation of TNF-α in a dose-dependent manner. IL-8 production by LPS was significantly suppressed by the CAPE pretreatment. Furthermore, LPS-induced IκB-α degradation was suppressed by the CAPE pretreatment.

Sinefungin, a Natural Nucleoside Analogue of S-Adenosylmethionine, Inhibits Streptococcus pneumoniae Biofilm Growth

Pneumococcal colonization and disease is often associated with biofilm formation, in which the bacteria exhibit elevated resistance both to antibiotics and to host defense systems, often resulting in infections that are persistent and difficult to treat. We evaluated the effect of sinefungin, a nucleoside analogue of S-adenosylmethionine, on pneumococcal in vitro biofilm formation and in vivo colonization. Sinefungin is bacteriostatic to pneumococci and significantly decreased biofilm growth and inhibited proliferation and structure of actively growing biofilms but did not alter growth or the matrix structure of established biofilms. Sinefungin significantly reduced pneumococcal colonization in rat middle ear. The quorum sensing molecule (autoinducer-2) production was significantly reduced by 92% in sinefungin treated samples. The luxS, pfs, and speE genes were downregulated in biofilms grown in the presence of sinefungin. This study shows that sinefungin inhibits pneumococcal biofilm growth in vitro and colonization in vivo, decreases AI-2 production, and downregulates luxS, pfs, and speE gene expressions. Therefore, the S-adenosylmethionine (SAM) inhibitors could be used as lead compounds for the development of novel antibiofilm agents against pneumococci.

Vocal Fold Augmentation with Injectable Polycaprolactone Microspheres/Pluronic F127 Hydrogel: Long-Term In Vivo Study for the Treatment of Glottal Insufficiency

There is increasing demand for reconstruction of glottal insufficiency. Several injection materials have been examined for this purpose, but all had limitations, such as poor long-term durability, migration from the injection site, inflammation, granuloma formation, and interference with vocal fold vibration due to viscoelastic mismatch. Here, we developed a novel injection material, consisting of polycaprolactone (PCL) microspheres, which exhibits better viscoelasticity than conventional materials, and Pluronic F127 carrier, which decreases the migration of the injection materials. The material was injected into rabbits with glottal insufficiency and compared with the FDA-approved injection material, calcium hydroxylapatite (CaHA). Endoscopic and histological examinations indicated that PCL/Pluronic F127 remained at the injection site with no inflammatory response or granuloma formation, whereas CaHA leaked out and migrated from the injection site. Therefore, vocal fold augmentation was almost completely retained during the 12-month follow-up period in this study. Moreover, induced phonation and high-speed recording of vocal fold vibration showed decreased vocal fold gap area in the PCL/Pluronic F127 group. Our newly developed injection material, PCL/Pluronic F127, permits efficient augmentation of paralyzed vocal fold without complications, a concept that can be applied clinically, as demonstrated by the successful long-term follow-up.

Tracheal reconstruction with asymmetrically porous polycaprolactone/pluronic F127 membranes

Congenital and acquired tracheal stenosis continues to be challenging problems. The purpose of this study was to evaluate the efficacy of an asymmetrically porous membrane (APM) to induce tracheal reconstruction by inhibition of granulation tissue growth into the tracheal lumen whereas minimizing graft failure.

Polycaprolactone spheres and theromosensitive pluronic F127 hydrogel for vocal fold augmentation: In vivo animal study for the treatment of unilateral vocal fold palsy

The purpose of this study was to explore a novel strategy to restore vocal gap by using polycaprolactone (PCL) spheres with thermosensitive Pluronic F127 in a paralyzed rabbit vocal fold.

Antimicrobial activities of Eugenia caryophyllata extract and its major chemical constituent eugenol against Streptococcus pneumoniae.

In this study, we investigate the antimicrobial activities of both Eugenia caryophyllata (Ec) extract and its major component eugenol (4‐allyl‐2‐methoxyphenol) against Streptococcus pneumoniae. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by microdilution method. Pneumococcal biofilms were detected by crystal‐violet microtiter plate assay, followed by colony‐forming unit counts and visualized by scanning electron microscope (SEM). The synergistic effect of eugenol and penicillin was determined by checker‐board method. Both the eugenol and the Ec extract inhibited pneumococcal growth in a concentration‐dependent manner. The MIC and MBC of eugenol were 0.06% and 0.12%, respectively. Eugenol at a concentration of 0.12% completely killed S. pneumoniae within 60 min of exposure. The kill rate of planktonic cells was most rapid during the first 15 min of contact with eugenol. The addition of eugenol or Ec extract inhibited in vitro biofilm formation. In already established biofilms, the inhibitory effect of eugenol or Ec extract was more significant in terms of cell viability than in terms of disruption of the biofilm matrix. SEM analysis revealed non‐viable and disruptive action of eugenol on the cell membrane of bacteria of biofilms. It was found that eugenol and penicillin produced a synergistic effect against S. pneumoniae. In conclusion, eugenol and Ec extract efficiently inhibited S. pneumoniae in planktonic growth and within biofilms.

Skull base vascular anomaly in CHARGE syndrome: a case report and review.

CHARGE syndrome was first described by Pagon, and was named for its six major clinical features, which are; coloboma of the eye, heart defects, atresia of the choanae, retarded growth and developmental anomalies, which include CNS anomalies, genital hypoplasia and/or urinary tract anomalies, and ear anomalies and/or hearing loss. The authors experienced a case of CHARGE syndrome that displayed bilateral jugular foramen atresia and a collateral emissary vein. In addition, the authors reviewed the literatures pertaining to CHARGE syndrome.

Role of group 3 innate lymphoid cells during experimental otitis media in a rat model

The objective of this study was to evaluate the role of group 3 innate lymphoid cells (ILC3) in the middle ear (ME) mucosal response to bacterial infection in a rat model. To confirm the role of ILC3 in bacterially induced otitis media (OM), the serum concentrations of IL-17 and IL-22 were determined by ELISA, and the tissue expression of IL-17 and IL-22 in infected ME mucosa was assessed by immunohistochemical staining. Immunohistochemical staining of specific cell surface markers was also assessed to confirm the origin of the cells expressing IL-17 and IL-22. Twenty Sprague-Dawley rats were used in the surgically-induced animal model of OM. OM was induced by inoculation of non-typeable Haemophilus influenzae into the ME cavity of the rats. The rats were divided into four experimental groups: three infected groups and one control group. Infected groups were subdivided into sets of 5 rats, one for each of the three time points (1, 4 and 7 days post-inoculation). For determination of rat IL-17 and IL-22 levels in infected rats and control rats, infected or control ME mucosa sections were analyzed by immunohistochemistry with specific antibodies directed against IL-17 and IL-22. Immunohistochemical staining for CD3, RORγt, and NKp46 were also conducted on the samples to confirm the origin of cells expressing IL-17 and IL-22. IL-17 and IL-22 serum concentrations were significantly increased in the infected rats compared to control rats. Immunohistochemical staining revealed increased IL-17 and IL-22 expressions in all infected ME mucosae from the first day after inoculation. In addition, the results of tissue staining for the specific surface markers were negative for CD3 and NKp46, but were highly positive for RORγt. IL-17 and IL-22 revealed their association with the bacterially induced proliferative and hyperplastic responses of ME mucosa, which are characteristic features in pathogenesis of OM. Surface marker examination showed that the source cells for IL-17 and IL-22 seemed to be lymphoid tissue inducer (LTi) cells. The results suggest that LTi cells release IL-17 and IL-22, and play a significant role in both the early phase of OM induction and recovery from it.

Selective Delivery of a Therapeutic Gene for Treatment of Head and Neck Squamous Cell Carcinoma Using Human Neural Stem Cells

Objectives Based on studies of the extensive tropism of neural stem cells (NSCs) toward malignant brain tumor, we hypothesized that NSCs could also target head and neck squamous cell carcinoma (HNSCC) and could be used as a cellular therapeutic delivery system. Methods To apply this strategy to the treatment of HNSCC, we used a human NSC line expressing cytosine deaminase (HB1.F3-CD), an enzyme that converts 5-fluorocytosine (5-FC) into 5-fluorouracil (5-FU), an anticancer agent. HB1. F3-CD in combination with 5-FC were cocultured with the HNSCC (SNU-1041) to examine the cytotoxicity on target tumor cells in vitro. For in vivo studies, an HNSCC mouse model was created by subcutaneous implantation of human HNSCC cells into athymic nude mice. HB1.F3-CD cells were injected into mice using tumoral, peritumoral, or intravenous injections, followed by systemic 5-FC administration. Results In vitro, the HB1.F3-CD cells significantly inhibited the growth of an HNSCC cell line in the presence of the 5-FC. Independent of the method of injection, the HB1.F3-CD cells migrated to the HNSCC tumor, causing a significant reduction in tumor volume. In comparison to 5-FU administration, HB1.F3-CD cell injection followed by 5-FC administration reduced systemic toxicity, but achieved the same level of therapeutic efficacy. Conclusion Transplantation of human NSCs that express the suicide enzyme cytosine deaminase combined with systemic administration of the prodrug 5-FC may be an effective regimen for the treatment of HNSCC.

Quantitative evaluation of laryngeal function in glottal insufficiency animal model for tissue engineering approach

Injection laryngoplasty is widely used for treatment of vocal fold palsy. To test the efficacy and safety of newly developed injection materials for vocal fold augmentation, we need reliable animal model for objective evaluation of glottal insufficiency. In this study, we aimed to develop an animal model to quantitatively evaluate the histological and functional changes of the paralyzed vocal fold. Left side recurrent laryngeal nerves were identified at tracheoesophageal groove of the New Zealand white rabbits and they were resected. Endoscopic examination was performed immediately after operation and 1, 2, 4, 8, 12 week after the operation to identify left vocal fold immobility. Total laryngectomy was performed 1, 2, 4, 8, 12 weeks after the operation. We have developed the method to quantify the changes of the intralaryngeal muscles. Histologic exam revealed significant decrease in thyroarytenoid muscle volume in the paralyzed side 12 weeks after the operation. We have also developed the method to quantify the laryngeal functions by analyzing vocal fold vibration. High speed recording of induced phonation showed irregular and asymmetric movement of vocal fold in the glottal insufficiency model. Videokymographic analysis showed increased open quotient and asymmetric index compared with the normal vocal fold. This model could be used to provide fundamental changes related with vocal fold paralysis. Even more, this animal model could be utilized to test efficacy and safety of various injection materials to augment the vocal fold.