Jeon, Hyeran H
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Publication FOXO1 Differentially Regulates Both Normal and Diabetic Gingival Wound Healing(2016-07-29) Jeon, Hyeran HWe have previously demonstrated that keratinocyte-specific forkhead box O1 (FOXO1) deletion interferes with keratinocyte migration in normal skin wounds. However it has an opposite effect in diabetic skin wounds, significantly improving the healing response. In addition we found that skin epithelium regulates connective tissue healing mediated by FOXO1, which is strongly associated with wound angiogenesis in our microarray results. However, a role for keratinocytes in this complex process has yet to be investigated. To this end, we investigated possible involvement of gingival keratinocytes in connective tissue healing under both normal and diabetic conditions. We found that keratinocyte-specific FOXO1 deletion interfered with normal gingival connective tissue healing by decreasing granulation tissue formation and angiogenesis, which were mediated by vascular endothelial growth factor A (VEGF-A). In particular this is the first evidence that avascular epithelium regulates angiogenesis involving the VEGF-A secretion mediated by FOXO1. Furthermore, we investigated the possible role of epithelial to mesenchymal transition (EMT) during wound healing using the lineage tracing in transgenic mice. But we did not find any keratinocyte-specific reporter activity in the connective tissue indicating that there was no apparent trans-differentiation of keratinocytes into typical fibroblasts or myofibroblasts during wound healing. These results establish an important role of epithelial cells in accelerating wound angiogenesis and connective tissue healing through a FOXO1-dependent mechanism.Publication RANKL Deletion in Periodontal Ligament and Bone Lining Cells Blocks Orthodontic Tooth Movement(2018-02-26) Jeon, Hyeran H; Alshabab, Ahmed; Lee, Yu Jin; Yang, Chia-Ying; Chung, Chun-HsiThe bone remodeling process in response to orthodontic forces requires the activity of osteoclasts to allow teeth to move in the direction of the force applied. Receptor activator of nuclear factor-κB ligand (RANKL) is essential for this process although its cellular source in response to orthodontic forces has not been determined. Orthodontic tooth movement is considered to be an aseptic inflammatory process that is stimulated by leukocytes inclduing T and B lymphocytes which are presumed to stimulate bone resorption. We determined whether periodontal ligament and bone lining cells were an essential source of RANKL by tamoxifen induced deletion of RANKL in which Cre recombinase was driven by a 3.2 kb reporter element of the Col1α1 gene in experimental mice (Col1α1.CreERTM+.RANKLf/f) and compared results with littermate controls (Col1α1.CreERTM-.RANKLf/f). By examination of Col1α1.CreERTM+.ROSA26 reporter mice we showed tissue specificity of tamoxifen induced Cre recombinase predominantly in the periodontal ligament and bone lining cells. Surprisingly we found that most of the orthodontic tooth movement and formation of osteoclasts was blocked in the experimental mice, which also had a reduced periodontal ligament space. Thus, we demonstrate for the first time that RANKL produced by periodontal ligament and bone lining cells provide the major driving force for tooth movement and osteoclastogenesis in response to orthodontic forces.Publication FOXO1 Deletion in Keratinocytes Improves Diabetic Wound Healing through MMP9 Regulation(2017-09-05) Zhang, Chenying; Jeon, Hyeran H; Lim, Jason; Xu, Fanxing; Tian, Chen; Miao, Fang; Graves, Dana T; Hameedaldeen, AlhassanKeratinocyte migration is a key aspect of re-epithelialization during wound healing. Matric metalloproteinase 9 (MMP9) contributes to this process and deificiencies in the MMP9 lead to impaired healing. Inappropriate expression of MMP9 also contributes to impaired re-epithelialization. Previously we demonstrated that FOXO1 was activated in wound healing but to higher levels in diabetic wounds. To address mechanisms of impaired re-epithelialization we examined MMP0 expression in vivo in full thickness dermal scalp wounds creared in experimental K14.Cre+.Foxo1L/L mice with lineage-specific Cre recombinase deletion of floxed FOXO1 and compared the results to control littermates. MMP9 was induced during wound healing but at a significantly higher level in diabetic compared to normal wounds. FOXO1 deletion substantially blocked this increase. By chromatin immunoprecipitation FOXO1 was shown to bind to the MMP9 promoter, FOXO1 overexpression increased MMP9 transcriptional activity and increased MMP9 expression simulated by high glucose that was blocked by FOXO1 deletion or FOXO1 knockdown. We also show for the first time that high glucose impairs keratinocyte migration by inducing high levels of MMP9 expression in diabetic wound healing, which represents a novel mechanism for impaired re-epithelialization in diabetic wounds.Publication Effects of Maxillary Sinus Graft on the Survival of Endosseous Implants: A 10-Year Retrospective Study(2008-08-01) Jeon, Hyeran H; Pang, Eun-Kyoung; Pae, Ah-Ran; Kim, Myung-Rae; Kang, Na-RaPurpose: The aim of this study was to determine the survival rates of implants placed in grafted maxillary sinuses and compare the results obtained with graft materials, implant surfaces and timing of implant placement. Materials and Methods: Between January 1996 and December 2005, 391 implants are placed in 161 patients who underwent sinus grafting treatment simultaneously or separately at Ewha Womans University Hospital. According to inclusion critieria, 272 impants were placed in 102 patients with 112 sinus grafts (30 females, 72 males), aged 26 to 88 years (mean age 49.0±9.7). The follow-up period ranged from 12 to 134 months (mean F/U 47±32). Survival rates were evaluated according to graft material, implant surface and timing of implant placement, The Kaplan-Meier procedure and the log rank (Mantel-Cox) test were used to estimate survival rates and test for equality of survival rates between different groups of patients. Results: Ten-year cumultative survival rate for implants placed in the grafted sinuses was 90.1%. The survival rates for autogenous bone, combination and bone substitutes were 94.6%, 85.9% and 100% respectively (p>0.05). According to implant surface, survival rates were 84.8% in machined group and 97.5% in rough group (p0.05). Conclusion: Ten-year cumultative survival rate for implants placed in the grafter sinuses was 90.1% Rough-shaped implants have a higher survival rate than machined-surface implants when placed in grafted sinuses. (p<0.05).Publication Anxiety Control and Periodontal Practice(2005-09-01) Lee, Seoung-Ho; Lee, Jun-Young; Jeon, Hyeran H; Han, Gum-AhaChronic periodontitis is one of the most common diseases in clinical dentistry, which requires various surgical interventions to treat the moderately to severely destructed supporting periodontium. Most patients have anxiety and fear to those surgical procedures and dentists often have problems dealing with those patients. By applying the conscious sedation technique in outpatient units, periodontists have become able to manage their patients successfully with less anxiety or fear. Also, we have experienced the increased level of patients' satisfaction. Generally, periodontal treatments are time consuming procedures and patients are usually reluctant to the periodontal instruments. This study is focused on the sedation procedure with intravenous midazolam infusion performed in Department of Periodontology of Ewha Womans University Hospital. Using questionnaires, we evaluated 80 randomly selected patients for the anxiolytic effect of intravenous midazolam. Anxiety control using IV sedation was very helpful in performing various periodontal reconstructive and advanced surgical procedures in implant dentistry.Publication Experimental Study on the Acellular Demal Matrix Graft for the Root Coverage in Dog(2006-03-01) Cho, Min-Young; Lee, Seoung-Ho; Han, Keum-Ah; Lee, Jun-Young; Jeon, Hyeran H; Kang, Na-Ra; Kim, Myung-RaeMucogingival surgery is a plastic surgical procedure designed to correct defects in the morphology, position, and dimensions of the gingiva surrounding the teeth. Many surgical techniques have been reported in mucogingival surgery. Since these procedures also include the soft tissue esthetic approach, the term "periodontal plastic surgery" has been proposed to be more appropriate.1 Root coverage is a procedure that falls with this definition, and it has attracted more interest than others.Publication The Effect of Ca-P Coated Bovine Bone Mineral on Bone Regeneration around Dental Implant in Dogs(2006-12-01) Cho, Su-Yeon; Jeon, Hyeran H; Lee, Sun-Kyoung; Lee, Seoung-Ho; Lee, Jun-Young; Han, Keum-AhThere are many obstacles to overcome in implant dentistry. The bony defect around implant can be seen in immediate installation procedures. Following tooth extraction, however, a socket often presents dimensions that may be considerably greater than the dimensions of a conventional implant.