Sung-Lyong Hong

Adipose-Derived Stem Cells Ameliorate Allergic Airway Inflammation by Inducing Regulatory T Cells in a Mouse Model of Asthma

Although several studies have demonstrated that mesenchymal stem cells derived from adipose tissue (ASCs) can ameliorate allergic airway inflammation, the immunomodulatory mechanism of ASCs remains unclear. In this study, we investigated whether regulatory T cells (Tregs) induction is a potential mechanism in immunomodulatory effects of ASCs on allergic airway disease and how these induced Tregs orchestrate allergic inflammation. Intravenous administration of ASCs significantly reduced allergic symptoms and inhibited eosinophilic inflammation. Airway hyperresponsiveness, total immune cell and eosinophils in the bronchoalveolar lavage fluid, mucus production, and serum allergen-specific IgE and IgG1 were significantly reduced after ASCs administration. ASCs significantly inhibited Th2 cytokines (IL-4, IL-5, and IL-13) and enhanced Th1 cytokine (IFN-γ) and regulatory cytokines (IL-10 and TGF-β) in the bronchoalveolar lavage fluid and lung draining lymph nodes. Furthermore, levels of IDO, TGF-β, and PGE2 were significantly increased after ASCs administration. Interestingly, this upregulation was accompanied by increased Treg populations. In conclusion, ASCs ameliorated allergic airway inflammation and improved lung function through the induction of Treg expansion. The induction of Treg by ASCs involves the secretion of soluble factors such as IDO, TGF-β, and PGE2 and Treg might be involved in the downregulation of Th2 cytokines and upregulation of Th1 cytokines production.

Inverted papilloma of the nasal cavity and paranasal sinuses: A Korean multicenter study

The study group for sinonasal tumors at the Korean Rhinologic Society analyzed the results of the Korean multicenter experience for sinonasal inverted papilloma (IP) surgeries.

Analysis of upper airway obstruction by sleep videofluoroscopy in obstructive sleep apnea: a large population-based study.

To analyze the pattern of the upper airway obstruction in a large cohort of obstructive sleep apnea (OSA) patients using sleep videofluoroscopy (SVF).

Effect of uvulopalatopharyngoplasty on positional dependency in obstructive sleep apnea.

OBJECTIVE To assess the effect of uvulopalatopharyngoplasty (UPPP) on positional dependency in patients with obstructive sleep apnea (OSA). DESIGN Retrospective analysis. SETTING Tertiary care university hospital. PATIENTS Ninety-six patients who underwent UPPP because of OSA from June 1, 2004, through July 31, 2008, were included. Both preoperative and postoperative attended full-night polysomnography were conducted in all patients. Positional dependency was diagnosed if the patients apnea-hypopnea index score in the supine position was more than twice as high as that in the lateral position. MAIN OUTCOME MEASURES Position-specific outcomes of UPPP, such as the success rates in the supine or lateral position, were assessed, as well as overall treatment outcomes. The outcomes were also analyzed according to the severity level of the apnea-hypopnea index in each position. The change of positional dependency after UPPP was evaluated. RESULTS The apnea-hypopnea index score in the lateral position was markedly reduced after UPPP in position-independent patients (P = .02). However, the overall success rates were only 31.8% and 34.6% in patients with and without positional dependency, respectively. The success rate in the lateral position was 68.2% in position-independent patients and 32.7% in position-dependent patients (P = .01). In addition, 14 of 22 patients with position-independent OSA (64%) gained positional dependency after UPPP. CONCLUSIONS Uvulopalatopharyngoplasty is successful treatment for obstructive events occurring in the lateral sleep position, especially in patients without positional dependency. This implies that patients who have become position dependent may benefit from positional therapy after UPPP.

A comparison of dexmedetomidine versus propofol during drug-induced sleep endoscopy in sleep apnea patients.

In this study, we compared the effects of propofol and dexmedetomidine on the upper airway collapse pattern and cardiopulmonary parameters of patients with obstructive sleep apnea (OSA) undergoing drug‐induced sleep endoscopy (DISE).

Smoking and malignancy in sinonasal inverted papilloma

The authors investigated clinical features of squamous cell carcinomas (SCC) arising in sinonasal inverted papillomas (IP) and risk factors responsible for their malignant transformation.

Inflammation and apoptosis in malignant transformation of sinonasal inverted papilloma: the role of the bridge molecules, cyclooxygenase-2, and nuclear factor κB.

PURPOSE This study examined the early events in the neoplastic progression of the sinonasal inverted papilloma to squamous cell carcinoma from the viewpoint of chronic inflammation and apoptosis. MATERIALS AND METHODS In total, 118 archival slides stained with hematoxylin and eosin from 45 patients were graded according to histopathology (grades I-IV). Their representative portions were transferred to a tissue microarray, sections of which were stained immunohistochemically for cyclooxygenase-2, p53, bax, bcl-2, and nuclear factor κB. RESULTS Cyclooxygenase-2 expression was positively correlated with histopathologic grade, with higher expression in advanced grades. p53s were detected in all cores from advanced grades (III, IV), but not in early grades (I, II). The expressions of nuclear factor κB, bax, and bcl-2 were not correlated with the grade. CONCLUSIONS A p53 mutation seems be a critical event for the malignant transformation of the sinonasal inverted papilloma. Cyclooxygenase-2-mediated inflammatory signals, activated as a consequence of the p53 mutation, may contribute to promoting the proliferation of the advanced sinonasal inverted papilloma.

Smoking, not human papilloma virus infection, is a risk factor for recurrence of sinonasal inverted papilloma.

Background The recurrence rate of sinonasal inverted papillomas (SNIP) is 15–20%. However, few studies have investigated patient-dependent factors related to recurrence of SNIPs. Objective To analyze risk factors, including human papilloma virus (HPV) infection and smoking, as well as other factors, for recurrence of SNIPs. Methods Fifty-four patients who were diagnosed with SNIP and underwent surgery were enrolled: 39 men and 15 women, with the mean age of 54.0 years. Their mean follow-up was 40.6 months. Demographics and information about the history of smoking, previous surgery, tumor extent, follow-up, and recurrence were reviewed retrospectively. Those patients whose tumors were associated with malignant transformation were excluded in this study. HPV detection and genotyping in the tumor specimens were performed with the HPV DNA chip, a polymerase chain reaction-based DNA microarray system. Results Seven patients (13.0%) had recurrence, with a mean time to recurrence of 39.8 months. Recurrence rates in T1, T2, T3, and T4 of the Krouse staging system were 0% (0/4), 8.3% (2/24), 17.4% (4/23), and 33.3% (1/3), respectively (p > 0.5). Eight patients (14.8%) were positive for HPV DNA. All of these patients belonged to the group without recurrence (p > 0.5). However, recurrence rates according to HPV DNA positivity were not statistically different (0% versus 15.2%). Three (42.9%) in the group with recurrence and four (8.5%) in the group without recurrence were smokers (p < 0.5). Conclusion Smoking was associated with recurrence of SNIP. However, HPV infection is not a recurrence of SNIP risk factor.

Immunomodulatory Effect of Mesenchymal Stem Cells on T Lymphocyte and Cytokine Expression in Nasal Polyps

Objectives Adipose tissue–derived stem cells (ASCs) have been reported to have immunomodulatory effects in various inflammatory diseases, including asthma and allergic rhinitis, through the induction of T cell anergy. Nasal polyps (NPs) are a chronic inflammatory disease in the nose and paranasal sinus characterized histologically by the infiltration of inflammatory cells, such as eosinophils or lymphocytes. This study was performed to investigate whether ASCs have immunomodulatory effects on T lymphocyte and cytokine expression in eosinophilic NPs. Study Design Basic science experimental study. Setting University tertiary care facility. Subjects and Methods NP specimens were obtained from 20 patients with chronic rhinosinusitis and eosinophilic NPs. ASCs were isolated and cultured from the abdominal fat of 15 subjects undergoing intra-abdominal surgery. Infiltrating cells (1 × 106) were isolated from NP tissue and co-cultured with 1 × 105 ASCs. To determine whether ASCs affect infiltrating T lymphocyte and cytokine expression in eosinophilic NP, T lymphocyte subsets and cytokine expression were analyzed before and after ASC treatment. Results ASC treatment significantly decreased the proportions of CD4+ and CD8+ T cells. After ASC treatment, Th2 cytokine (interleukin [IL]–4 and IL-5) levels decreased significantly. In contrast, levels of Th1 (interferon-γ and IL-2) and regulatory cytokines (transforming growth factor–β and IL-10) increased significantly after ASC treatment. Conclusions ASCs have immunomodulatory effects in the eosinophilic inflammation of NPs, characterized by down-regulation of activated T lymphocytes and a Th2 immune response. These effects would be expected, over time, to significantly contribute to the control of eosinophilic inflammation and, possibly, growth of eosinophilic NPs.

Inverted papilloma of the maxillary sinus: Surgical approach and long-term results.

Background Inverted papillomas (IP) commonly develop in the maxillary sinus (MS). However, the MS is a complex structure, and all areas in the MS are not easily approachable. Objective This study reviewed our surgical outcome of patients with IPs that originated from the MS in long-term follow-up and suggests appropriate approaches according to the tumor origin. Methods Thirty-one patients who were diagnosed with IP that originated from the MS, underwent surgery by a single operator between 1999 and 2011, and had postoperative follow-up of >3 years were enrolled. Results In all the cases, the endoscopic endonasal approach (EEA) was attempted at first and then canine fossa puncture (CP), canine fossa opening via the Caldwell-Luc approach (CO), and Caldwell-Luc operation (CLO) were added in consecutive order as the occasion demands. Six patients (19.4%) were treated only with EEA, and they had IPs from the superior, posterior, or medial wall. Five (16.1%) were treated with EEA plus CP, which was added for removal of IPs that originated from the lateral wall. Sixteen (51.6%) were treated with EEA plus CO, which was for removal of tumors from the medial, anterior, or inferior wall. Four patients (12.5%) whose IP attached to the whole MS mucosa underwent CLO. Three (9.7%) experienced recurrences, and the mean period to recurrence was 20.7 months. Conclusion The overall recurrence rate was 9.7%. IPs that originated from the lateral wall of the MS can be removed by using CP. When IPs originate from the anterior, inferior, or medial wall of the MS, CO may be needed for the thorough removal of them.