Hyon-Seok Jang

Demineralized dentin matrix combined with recombinant human bone morphogenetic protein-2 in rabbit calvarial defects

Objectives The aim of this study was to compare the osteogenic effects of demineralized dentin matrix (DDM) combined with recombinant human bone morphogenetic protein-2 (rhBMP-2) in rabbit calvarial defects with DDM and anorganic bovine bone (ABB) combined with rhBMP-2. Materials and Methods Four round defects with 8-mm diameters were created in each rabbit calvaria. Each defect was treated with one of the following: 1) DDM, 2) ABB/rhBMP-2, or 3) DDM/rhBMP-2. The rhBMP-2 was combined with DDM and ABB according to a stepwise dry and dip lyophilizing protocol. Histological and microcomputed tomography (µCT) analyses were performed to measure the amount of bone formation and bone volume after 2- and 8-week healing intervals. Results Upon histological observation at two weeks, the DDM and ABB/rhBMP-2 groups showed osteoconductive bone formation, while the DDM/rhBMP-2 group showed osteoconductive and osteoinductive bone formation. New bone formation was higher in DDM/rhBMP-2, DDM and ABB decreasing order. The amounts of bone formation were very similar at two weeks; however, at eight weeks, the DDM/rhBMP-2 group showed a two-fold greater amount of bone formation compared to the DDM and ABB/rhBMP-2 groups. The µCT analysis showed markedly increased bone volume in the DDM/rhBMP-2 group at eight weeks compared with that of the DDM group. Notably, there was a slight decrease in bone volume in the ABB/rhBMP-2 group at eight weeks. There were no significant differences among the DDM, ABB/rhBMP-2, and DDM/rhBMP-2 groups at two or eight weeks. Conclusion Within the limitations of this study, DDM appears to be a suitable carrier for rhBMP-2 in orthotopic sites.

Transmembrane protein 173 inhibits RANKL-induced osteoclast differentiation

Tmem173 was identified as a growth inhibitor associated with major histocompatibility complex (MHC) class II and a potential stimulator for IFN‐β, an innate immune inducer and a negative feedback controller for RANKL‐induced osteoclast differentiation of monocytic macrophage cells. In this study, we confirmed that transmembrane protein 173 (Tmem173) overexpression inhibited the expression of osteoclast‐specific genes, tartrate‐resistant acid phosphatase (TRAP), cathepsin K, and matrix metalloproteinase‐9 (MMP‐9), as well as bone resorption pit formation in RANKL‐treated RAW 264.7 cells. Activation of osteoclast‐specific transcription factors, c‐Fos and nuclear factor of activated T cells cytoplasmic‐1 (NFATc1), and RANKL‐induced activation of ERK were also down‐regulated by Tmem173 overexpression. Collectively, these results suggest that Tmem173 plays a regulatory role in RANKL–RANK‐mediated signaling in osteoclastogenesis.

Red ginseng powder fermented with probiotics exerts antidiabetic effects in the streptozotocin-induced mouse diabetes model

Abstract Context: Red ginseng (heat-processed Panax ginseng) is a well-known alternative medicine with pharmacological antidiabetic activity. It exerts pharmacological effects through the transformation of saponin into metabolites by the intestinal microbiota. Given that intestinal conditions and intestinal microflora vary among individuals, the pharmacological effects of orally administered red ginseng likely may vary among individuals. Objective: To overcome this variation and produce homogeneously effective red ginseng, we evaluated the antidiabetic effects of probiotic-fermented red ginseng in a mouse model. Materials and methods: The antidiabetic efficacy of orally administered probiotic-fermented red ginseng was assessed in ICR mice after induction of diabetes using streptozotocin (170 mg/kg body weight). Samples were given orally for 8 weeks, and indicators involved in diabetic disorders such as body weight change, water intake, blood glucose, glucose tolerance and various biochemical parameters were determined. Results: Oral administration of probiotic-fermented red ginseng significantly decreased the level of blood glucose of about 62.5% in the fasting state and induced a significant increase in glucose tolerance of about 10.2% compared to the control diabetic mice. Additionally, various indicators of diabetes and biochemical data (e.g., blood glycosylated haemoglobin level, serum concentrations of insulin, and α-amylase activity) showed a significant improvement in the diabetic conditions of the mice treated with probiotic-fermented red ginseng in comparison with those of control diabetic mice. Discussion and conclusion: Our results demonstrate the antidiabetic effects of probiotic-fermented red ginseng in the streptozotocin-induced mouse diabetes model and suggest that probiotic-fermented red ginseng may be a uniformly effective red ginseng product.

Oral administration of red ginseng powder fermented with probiotic alleviates the severity of dextran-sulfate sodium-induced colitis in a mouse model

Red ginseng is a well-known alternative medicine with anti-inflammatory activity. It exerts pharmacological effects through the transformation of saponin into metabolites by intestinal microbiota. Given that intestinal microflora vary among individuals, the pharmacological effects of red ginseng likely vary among individuals. In order to produce homogeneously effective red ginseng, we prepared probiotic-fermented red ginseng and evaluated its activity using a dextran sulfate sodium (DSS)-induced colitis model in mice. Initial analysis of intestinal damage indicated that the administration of probiotic-fermented red ginseng significantly decreased the severity of colitis, compared with the control and the activity was higher than that induced by oral administration of ginseng powder or probiotics only. Subsequent analysis of the levels of serum IL-6 and TNF-α, inflammatory biomarkers that are increased at the initiation stage of colitis, were significantly decreased in probiotic-fermented red ginseng-treated groups in comparison to the control group. The levels of inflammatory cytokines and mRNAs for inflammatory factors in colorectal tissues were also significantly decreased in probiotic-fermented red ginseng-treated groups. Collectively, oral administration of probiotic-fermented red ginseng reduced the severity of colitis in a mouse model, suggesting that it can be used as a uniformly effective red ginseng product.

Mandibular stability using sliding or conventional four-hole plates for fixation after bilateral sagittal split ramus osteotomy for mandibular setback.

Our aim was to compare the postoperative stability of the mandible when two different fixation methods had been used after bilateral sagittal split ramus osteotomy (BSSRO) for mandibular setback. The study included 23 patients who had two-jaw BSSRO mandibular setback at the Department of Oromaxillofacial Surgery, Korea University Guro Hospital, between January 2011 and June 2014. The first group (four-hole (control) group, n=13) comprised patients whose bony segments were fixed with conventional four-hole plates, and the second (sliding plate (experimental) group, n=10) included patients whose bone segments were fixed with sliding plates. Lateral cephalograms were taken and analysed at three time points: preoperatively (T1), and one week (T2), and 1year (T3) postoperatively. The Mann-Whitney U test was used to compare the postoperative stability of the mandible in each group. There were no significant differences between the two groups in changes in the horizontal and vertical positions of point B and pogonion postoperatively, nor were there any significant differences between them in ramal inclination and inclination of the SN plane with point B at the given time points (p=>0.05 in surgical changes in the mandible immediately after surgery and 0.397, 0.616, 0.082, 0.951, 0.901, 0.476 in postoperative changes in the mandible 1 week to 1 year after surgery). Like the conventional four-hole plate, the sliding plate can also be used to achieve stability in the fixation of mandibular bone segments after BSSRO.

Heterogeneous Nuclear Ribonucleoprotein A2B1 Exerts a Regulatory Role in Lipopolysaccharide-stimulated 38B9 B Cell Activation

Major histocompatibility complex (MHC) class II molecules, which are recognized for their primary function of presenting an antigen to the T cell receptor, are involved in various signaling pathways in B cell activation. We identified heterogeneous nuclear ribonucleoprotein (hnRNP) A2B1 as an MHC class II molecule-associated protein involved in MHC class II-mediated signal transduction in lipopolysaccharide (LPS)-stimulated 38B9 B cells. Although the function of hnRNP A2B1 in the nucleus is primarily known, the level of hnRNP A2B1 in the cytoplasm was increased in LPS-stimulated 38B9 cells, while it was not detected in the cytoplasm of non-treated 38B9 cells. The silencing of hnRNP A2B1 expression using siRNA disturbed B cell maturation by regulation of mitogen-activated protein kinase signaling, NF-κB activation, and protein kinase B activation. These results suggest that hnRNP A2B1 is associated with MHC class II molecules and is involved in B cell activation signaling pathways in LPS-stimulated 38B9 cells.