Lysophosphatidic acid (LPA) is a bioactive lipid messenger involved in the pathogenesis of chronic inflammation and various diseases. Recent studies have shown an association between periodontitis and neuroinflammatory diseases such as Alzheimer’s disease, stroke, and multiple sclerosis. However, the mechanistic relationship between periodontitis and neuroinflammatory diseases remains unclear. The current study found that lysophosphatidic acid receptors 1 (LPAR1) and 6 (LPAR6) exhibited increased expression in primary microglia and astrocytes. The primary astrocytes were then treated using medium conditioned to mimic periodontitis through addition of Porphyromonas gingivalis lipopolysaccharides, and an increased nitric oxide (NO) production was observed. Application of conditioned medium from human periodontal ligament stem cells with or without LPAR1 knockdown showed a decrease in the production of NO and expression of inducible nitric oxide synthase and interleukin 1 beta. These findings may contribute to our understanding of the mechanistic link between periodontitis and neuroinflammatory diseases.

Background: Anterior cruciate ligament reconstruction (ACLR) causes a reduction in the balance of the lower extremities. Static and dynamic balance were evaluated separately to confirm the decrease in balance in patients underwent ACLR. The commonly used methods include the Biodex Balance System (BBS) for static balance and the Y balance test (YBT) for dynamic balance. No study has evaluated whether the static and dynamic balance of the involved side recovers as much as the uninvolved side one year after ACLR. Objects: The purpose of this study was to investigate the recovery of static and dynamic balance between the involved and the uninvolved sides. Methods: The BBS (overall, anteroposterior index, and mediolateral index) and YBT (anterior, posterolateral, and posteromedial) of 58 patients underwent ACLR were measured one year postoperation. Both sides of the BBS and the YBT were compared using the paired t-test. Results: All the index of the BBS showed no difference between the involved and the uninvolved sides, while all the scores of the YBT showed a significant difference in both sides. The YBT anterior result was 54.64 ± 5.62 cm in the involved side and 56.90 ± 5.41 cm in the uninvolved side (p = 0.001). The YBT posterolateral results were 90.12 ± 10.51 cm and 92.34 ± 9.85 cm (p = 0.013). The YBT posteromedial results were 93.72 ± 8.84 cm and 96.14 ± 9.37 cm (p = 0.002). Conclusion: A year after ACLR, the static balance showed no difference, while the dynamic balance showed a significant difference in the involved and the uninvolved sides. The static balance of the involved side recovered as much as the uninvolved side, but the dynamic balance did not. Therefore, dynamic balance training should be considered in the rehabilitation program for patients underwent ACLR.

Lysophosphatidic acid (LPA) is a lipid messenger mediated by G protein-coupled receptors (LPAR1-6). It is involved in the pathogenesis of certain chronic inflammatory and autoimmune diseases. In addition, it controls the self-renewal and differentiation of stem cells. Recent research has demonstrated the close relationship between periodontitis and various diseases in the human body. However, the precise role of LPA in the development of periodontitis has not been studied. We identified that LPAR1 was highly expressed in human periodontal ligament stem cells (PDLSCs). In periodontitis-mimicking conditions with Porphyromonas gingivalis -derived lipopolysaccharide (Pg-LPS) treatment, PDLSCs exhibited a considerable reduction in the cellular viability and osteogenic differentiation potential, in addition to an increase in the inflammatory responses including tumor necrosis factor-α and interleukin-1β expression and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activation. Of the various LPAR antagonists, pre-treatment with AM095, an LPAR1 inhibitor, showed a positive effect on the restoration of cellular viability and osteogenic differentiation, accompanied by a decrease in NF-κB signaling, and action against Pg-LPS. These findings suggest that the modulation of LPAR1 activity will assist in checking the progression of periodontitis and in its treatment.

Periodontitis is an inflammatory disease of the supportive tissues surrounding the teeth, and is characterized by irreversible destruction of the gingiva, periodontal ligament (PDL), and alveolar bone, which results in the loss of teeth. In the present study, we elucidated the correlation between periodontitis and apelin (APLN), an adipokine and a regulatory peptide, respectively, which are involved in inflammation and bone remodeling. The expression of APLN is negatively correlated with periodontitis progression in gingival tissue. In addition, treatment with TNF-α downregulated the expression of APLN in PDL cells and gingival fibroblasts, indicating the protective role played by APLN against periodontitis progression. The overexpression of APLN or treatment with exogenous APLN suppressed the TNF-α- mediated catabolic gene expression of MMP1, IL6 , and PTGS2 in PDL cells. Moreover, the inhibition of the APLNAPJ axis by ML221, an APJ inhibitor, induced catabolic gene expression in PDL cells. Thus, the results of this study provided evidence to support APLN as a regulatory factor of the inflammatory response during periodontitis.

Transglutaminase2 (TGM2) is a multi-functional calcium dependent enzyme that affects angiogenesis, apoptosis, differentiation, attachment, and changes in the extracellular matrix. However, its function in periodontal tissue has not yet been studied. The aim of this study was to investigate the association of the TGM2 expression and the modulation of inflammatory mediators in inflamed periodontal ligament (PDL) cells induced by pro-inflammatory cytokines such as Interleukin-1β and the Tumor necrosis factor-α. The expression of TGM2 was increased in the inflamed periodontal tissue and PDL cells. Over-expressed TGM2 in the PDL cells increased expression of MMP1, MMP3, IL-6, CXCL8, and PTGS2. Conversely, inhibition of TGM2 activity using LDN27219, a TGM2 inhibitor, resulted in decreased expression of MMP1, MMP3, IL-6, and CXCL8. The mRNA expression was confirmed by RT-PCR and quantified by qRT-PCR. Protein levels were also confirmed by immunofluoroscence staining. These results suggest that TGM2 plays an important role in the regulation of inflammatory mediators which exacerbate tissue damage in inflamed periodontal tissue.

목 적 : 후방십자인대는 무릎 관절의 안정화를 위한 중요한 인대로 인체의 균형을 유지하는데 매우 중요한 역할을 한다. 본 연구에서는 후방십자인대의 해부학적 구조에 따라 사방향 관상면 영상과 이중 사방향 시상면 영상을 획득하여 그 유용성을 평가하고자 한다. 대상 및 방법 : 2016년 12월부터 2017년 1월까지 환자 20명을 대상으로 검사하였고 SIEMENS사의 Skyra 3.0T에서 knee coil을 사용하였다. 검사 방법은 T2 COR, PD SAG을 획득하고 원위부 후방십자인대의 해부학적 구조를 고려한 PD OBL COR과 전체적인 구조를 고려한 PD Dual OBL SAG을 획득하였다. PCL의 관상면 비교를 위하여 밑단점의 길이와 폭을 측정하여 비교하였고, 시상면 평가를 위하여 기시점, 중간지점, 밑단점을 측정하여 비교하였다. 측정결과를 Mann-Whitney 방법을 사용하여 통계적 유의성을 검정하였다. 정성적 방법은 기존의 관상면, 시상면 영상과 사방향 관상면, 이중 사방향 시상면 영상에서 후방십자인대를 비교하여 미흡, 대등, 우월 세 단계로 평가하였다. 결 과 : 검사를 진행한 결과 기존 관상면 영상보다 사방향 관상면 영상에서 원위부 후방십자인대의 길이는4 7.9%, 폭 14.9% 증가하였고, 기존 시상면 영상보다 이중 사방향 시상면 영상에서 기시점 19.8%, 중간지점 18.3%, 끝단점 33%의 증가된 것 으로 측정되었다. 결 론 : 사방향 관상면 영상과 이중 사방향 시상면 영상 모두 기존 영상보다 우월한 영상 검사방법으로 평가되었다. 이에 슬 관절 후방십자인대의 해부학적 관찰에는 기존 검사 방법에 사방향 관상면 영상 검사와 이중 사방향 시상면 영상 검사를 병 행하는 것이 유용할 것으로 사료된다.

Glucosamine is commonly taken by the elderly without prescription as a nutritional supplement to attenuate the progression or symptoms of osteoarthritis. Previous studies demonstrated that glucosamine shows anti-inflammatory effects in tissues such as blood vessels and the heart. However, there have been few reports about the effects of glucosamine on oral inflammatory diseases. Therefore, in this study, the effects of glucosamine on lipopolysaccharide (LPS)-induced inflammatory responses were investigated using human periodontal ligament fibroblasts (HPDLFs). HPDLFs were incubated in the presence and absence of glucosamine (10 mM) for 24 h, followed by treatment with E. coli LPS (100 ng/ml) or vehicle. Quantitative RT-PCR and ELISA results showed that LPS exposure significantly increased the levels of IL-6 and IL-8 mRNA and protein, while the effect was significantly suppressed by glucosamine treatment. Glucosamine did not attenuate, but slightly increased, the LPS-induced activation of mitogen activated kinases (ERK, p38, JNK). However, it suppressed the LPS-induced increase in the DNA binding affinity and transcriptional activity of NF-κB. These results suggest that glucosamine exerts anti-inflammatory effects on HPDLFs exposed to LPS via inhibition of NF-κB activity, necessitating further studies using animal periodontitis models.

Leptin is one of the adipocytokines produced from adi- pose tissue but its functions in periodontal tissue have not previously been investigated. In our current study, we exa- mined the effects of leptin on the expression of interleukin (IL)-6 and IL-8 in periodontal ligament (PDL) cells and gingival fibroblasts. Leptin receptor expression was evalua- ted by RT-PCR and the production of cytokines was mea- sured by ELISA. The phosphorylation of Akt and Erk1/2 was assessed by western blotting. mRNA of long and short form leptin receptors were detected in both PDL cells and gingival fibroblasts. Leptin was found to increase the pro- duction of IL-6 and IL-8 in both of these cell types, an effect which was not blocked by polymyxin B, an inhibitor of lipopolysaccharide (LPS). Leptin did not alter the pro- duction of IL-6 and IL-8 induced by LPS in PDL cells but increased Akt and Erk1/2 phosphorylation in these cells. These results suggest that leptin acts as an inducer of IL-6 and IL-8 in PDL cells and gingival fibroblasts.

Human β- defensin-2 (hBD-2) is an antimicrobial peptide which is produced by epithelial cells after stimulation with microorganisms or inflammatory mediators. However, little is known as to whether the LPS and nicotine induces the expression of hBD-2 in periodontal l igament (PDL) cells. T he p urpose o f this s tudy was t o investigate t he r oles o f MAPKs pathway o f nicotine a nd L PS-induced hBD-2 expression in PDL cells. The maximal expression of hBD-2 was observed in nicotine 5 mM and LPS 1 μg/ml treated PDL cells. Nicotine and LPS induced the phosphorylation of p38, c-Jun N-terminal kinase 1 and 2 (JNK1/2), and extracellular signal-regulated kinases 1 and 2 (ERK1/2) MAPK. ERK1/2 inhibitor SB203580, p38 inhibitor PD98059, and JNK inhibitor SP600125, blocked the effects of nicotine and LPS on hBD-2 upregulation in PDL cells. These results collectively suggest that hBD-2 is up-regulated in nicotine and LPS-treated PDL cells through activation of p38, ERK and JNK MAPKs pathway. Our data regarding the up-regulation of hBD-2 may help us to understand the antimicrobial mechanism in periodontal disease

The purpose of this study was to investigate the effect of cytokine-induced osteoclastogenesis on tooth movement related to orthodontic force. We evaluated the cytotoxicity as well as the expression of OPG and RANKL, which influence the homeostasis of bone metabolism. Titanium particles were applied to human periodontal ligament cells and subcultured fourth generation cells. The ALP assay and the MTT assay were used to assess changes in cytotoxicity. After 48 hours, cytotoxicity increased proportionally with the concentration of titanium. With 20 mg, the cytotoxicity was the lowest. R T-PCR was u sed for assessing m R NA l evels of O PG a nd R ANKL; after 96 hours, t he m R NAs of O PG a nd R ANKL increased steeply. A western blot analysis showed that with 20 mg of titanium, the protein expression of OPG increased linearly with time, especially a fter 96 hours, while t he p rotein e xpression o f RANKL d id n ot s how significant changes with titanium processing. Given the increase in OPG expression after the initial cytotoxicity, changes in cytotoxicity with titanium may be attributable to the antagonistic effect of OPG on cytotoxicity

In chronic ambulatory hemiplegic patients, structural changes might be developed at both ankles possibly due to unequal and repetitive weight bearing on tendons and ligaments. We examined ankles by sonography to find out structural changes of tendons and ligaments of both ankles in ambulatory hemiplegic patients. Nineteen ambulatory hemiplegic patients over 1 year were included as study subjects. All subjects had no previous trauma or disease history in their ankle joints and they were able to walk independently or with supervision but had spastic ankles with equinovarus tendency. We examined both ankle joints by sonography to see joint effusion and measure width, thickness, and area of tendons of the tibialis anterior, tibialis posterior, and Achilles, and also ligaments of the anterior talofibular and calcaneofibular. We compared sonographic features of the hemi-side ankle with the sound-side ankle. There were no significant differences between hemi-side and sound-side ankles in almost all measured parameters of tendons and ligaments. However, the width of the hemi-side tibialis posterior tendon (8.61±1.37 mm) was narrower than the sound-side tendon (7.24±1.52 mm). With the amount of active joint motion and weight bearing possibly preventing ligament and tendon atrophy even though marked weakness, spasticity occurred during the chronic hemiplegic phase.

Periodontal ligament (PDL) tissue is a connective tissue that is interposed between the roots of the teeth and the inner wall of the alveolar bone socket. PDL is always exposed to physiologic mechanical force such as masticatory force and PDL cells play important roles during orthodontic tooth movement by synthesizing and secreting different mediators involved in bone remodeling. The Wnt/β-catenin signaling pathway was recently shown to play a significant role in the control of bone formation. In the present study, we applied cyclic tensile stress of 20% elongation to cultured human PDL cells and assessed its impact after six days upon components of the Wnt/β-catenin signaling pathway. RTPCR analysis showed that Wnt1a, Wnt3a, Wnt10b and the Wnt receptor LRP5 were down-regulated, whereas the Wnt inhibitor DKK1 was up-regulated in response to these stress conditions. In contrast, little change was detected in the mRNA expression of Wnt5a, Wnt7b, Fz1, and LRP6. By western blotting we found decreased expression of the β-catenin and p-GSK-3β proteins. Our results thus show that mechanical stress suppresses the canonical Wnt/β-catenin signaling pathway in PDL cells.

Substance P (SP) is known to be expressed in the nerve fibers of dental pulp and periodontal tissues. It was recently reported that SP expression increased in response to orthodontic force. In the present study, we investigated the effect of SP on expression of mineralization markers and heme oxygenase-1 (HO-1) in human immortalized periodontal ligament (IPDL) cells. Cell viability was measured using a 3,4,5-dimethylthiazol-2-yl-2,5-diphenyl tetrazolium bromide (MTT) assay. The expression of mineralization markers, including alkaline phosphatase (ALP), osteonectin (ON) and bone sialoprotein (BSP), and heme oxygenase-1 (HO-1) was assessed by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis. SP did not significantly change human IPDL cell viability, with the exception of the 24 hour treatment group. Treatment of human IPDL cells with 10-10 to 10-⁴M SP upregulated mineralization marker and HO-1 expression in a time- and concentration-dependent manner. Our results suggest that SP may modulate osteoblastic cell differentiation of human IPDL cells through a mechanism involving HO-1 expression.

Although substance P (SP). a potent pro-inflammatory peptide, is involved in inflammation and immune responses, the effect of SP 011 the expression of macl'ophage inJlammatol'Y protein 3a (MIP-3a. CCL20) in periodontal ligament (PDL) cells a l'e unknown Equally as enigmatic is the link between SP. the stress protein heme oxygenase-l (HO-l) , and CCL20 product ion. We investigated whether SP induces the release of chemokine CCL20 from irrunortalized POL (IPDL) cells. and further claif’y SP mediated pathways . We also exarnined the relationship between HO-l and CCL20 by treating POL cells with SP Incubating IPOL cells with SP incl'eased ex pl'ession of CCL20 mRNA and CCL20 protein in a dose-time dependent manner. Highly selective p38 and ERKl/2 inhibitors abl'ogated SP-induced expression of CCL20 lD IPOL cells SP is also responsible fo l' ini tiating phosphorylation of I/( B‘ degl'adation of IK B. and activation of NF-/( B. SP induced expression of HO-l in both a concentration- and time-dependent manner. and CCL20 refl ected similal' patterns. The inductive effects of SP on HO-l and CCL20 were enhanced by HO- l inducer hemin and the membrane-permea ble cGMP analog 8-bromo-cGMP Conversely, this pathway was inhi bited by the HO-l inhibitor zinc Pl'otoporphyrin IX (ZnPP IX) and the selective inhibitor of guanylate cyclase‘ 1H- [1. 2. 4]uxad iazole[4, 3-alquinoxal i n- 1-one (ODQ) We report hel'ein the pathway that connects SP a long with other modulators 0 1' neuroimmunoregulationto the induction of HO-1 and the inflanunatol'y mediatol' MIP- 3a /CCL20 in IPDL cel ls. which play an impol'tant role in the development 0 1' pe- I'iodontitis or inflammation during ol'thodontic tooth movement

Periodontitis is a chronic infectious disease that leads to periodontal destruction, and is one of the major causes of tooth loss in humans. The osteoclast differentiation factor (ODF), which is also known as the receptor activator of the NF-kB ligand (RANKL), is a surface-associated ligand on bone marrow stromal cells and osteoblasts. RANKL activates its cognate receptor, RANK, on osteoclast progenitor cells, which leads to the differentiation of mononucleated precursor cells. Osteoprotegerin (OPG) is a decoy receptor that is released from stromal cells and osteoblasts to inhibit the interaction between RANKL and RANK. Although the precise mechanism of bone loss in periodontitis is unknown, the differentiation and activation of osteoclasts by OPG-ODF-RANK signaling might play the role in periodontal bone destruction. The relationship between the concentration of sex hormones and the expression of ODF and OPG was examined by treating human gingival fibroblasts and periodontal ligament cells with the normal serum concentration of estrogen or progesterone during menstruation or at menopause. The ODF/OPG relative ratio was elevated at the concentration observed during ovulation in human gingival fibroblasts and at the concentration observed between ovulation and menstruation in periodontal ligament cells treated with estrogen. However, the ratio was <1 at all concentrations in both cells treated with progesterone. In the case of menopause simulated by estrogen depletion, the ratio was <1 in human gingival fibroblasts but >1 in periodontal ligament cells.

Al t hough substance P(SP) , a potent pro- inflammatory peptide, is involved in inflammation and immune responses‘ t he eff'ect of SP on t he expression of macrophage inflammatory protein 3a (MIP- 3α CCL20) in periodontal liga ment(PDL) cell s a re unknown, Equally as enigmatic is the link between SP, t he stress protein heme oxygenase- l(HO-l) ‘ and CCL20 procluction, We investigated whether SP induces the release of chemokine CCL20 from immortal ized PDL(IPDL) ceJJ s‘ and fur ther c l a꺼 SP mediated pathways, We also examined the relationship between HO-l a ncl CCL20 by t reating PDL cells with SP, Incubating IPDL cells with SP increased expression of CCL20 mRNA a nd CCL20 protein in a dose-time dependent manner Highly selective p38 and ERKl/2 inhibitors abrogated SP-induced expression of CCL20 in IPDL cell s, SP is a lso responsible for ini t iating phosphorylation of I/C B, degradation of Iκ B‘ ancl activat ion of NF'-/C B, SP induced expression of HO-l in both a concentration- and time-dependent man nel ‘ and CCL20 refl ected s imilar patterns, The inductive effects o[ SP on HO- l and CCL20 wer e enhanced by HO- j inducer hemin and the membrane-permeable cGMP analog 8-bromo-cGMP, Conversely, this pathway was inJübited by t he 1-10난 inhi bitor zinc protoporphyrin IX(ZnPP IX) and the selective inl뼈itor of guanylate cyc1ase‘ lH-[l , 2, 4Joxad iazole[4‘ 3-aJquinoxal in-l-one (ODQ) , We report herein the pathway that connects SP along with other modulators 。f neuroimmunoregulationto the induction of HO-l and t he inflammatory mediator MIP-3a /CCL20 in IPDL cell s‘ which play an important role in the development 01' periodontitis or inflamrnation during orthodontic tooth movem

Periodontitis is a chronic infectious disease that leads to the destruction, one of the major cause of tooth loss in human. Osteoclast Differentiation Factor(ODF), also called as Receptor activator of NF-xB ligand(RANKL), a surface-associated ligand on bone marrow stromal cells and osteoblasts, activates its cognate receptor RANK on osteoclast progenitor cells, which leads to differentiation of these mononucleated precursor cells. Osteoprotegerin(OPG), a decoy receptor, is released from stromal cells and osteoblasts to inhibit the interaction between RANKL and RANK. The experiment for the effect of pregnancy on gingival health showed greater gingival inflammation and edema during pregnancy, despite similar plaque index. There should be many factors affecting the periodontal health in pregnancy. In this experiment, we examined the direct effects of sex hormones(estrogen and progesterone) on the ODF/OPG expression in human gingival fibroblasts and periodontal ligament cells at the serum concentration of pregnancy. The ratio was high in the 1st trimester of pregnancy by estrogen and in the late 2nd trimester by progesterone. Therefore, the local periodontal destruction might be accelerated by these hormonal effect on the periodontal cells.

The elderly suffer from an impaired immune function being obvious in a higher susceptibility to infections. Although the inflammatory cells are the major immunomodulatory cells, fibroblasts also secrete a variety of inflammatory cytokines and chemokines. Therefore periodontal tissue aging might playa role in development and progress of periodontitis. In this study, we investigated the effect of in vitro periodontal ligament cellular aging on the inflammatory cytokines, chemokines, and matrix metalloprotease(MMP)-2 expression induced by lipopolysaccharide(LPS) treatment. Three different cell populations were used; passages 4-5, 14-15, and 24-25 (at passage 27, more than 90% cells were replicative senescent). LPS increased the expression of interleukin(IL)-1β, IL-6, and tumor necrosis factor-α, IL-8, RANTES, and MMP-2. However, the order of induction folds were passages 14-15 > 4-5 > 24-25. While the expression level of Toll-like receptor(TLR) 4 decreased according to the increase in passage number, the level of TLR2 was highest at passages 14-15 and then decreased at passages 24-25. While the spontaneous expression of IL-8 decreased according to the increase in passage number, that of RANTES and proMMP-2 increased according to the increase in passage number. These results suggest that the aging of periodontal ligament fibroblasts differentially affect the role as immunomodulatory cells in response to periodontopathic bacteria and therefore might be another risk factor of periodontitis progression.

Periodontalligament (PDL) fibroblasts have an ectomesenchymal origin and are known to participate not only in formation of PDL but also in the repair and regeneration of the a이acent alveolar bone and cementum. However, little is known about the molecular mechanism which is related to the development and differentiation of PDL cells. Recendy, we reported the PDLs (a periodontalligament-specific) 22 as a PDL fibroblast-specific mRNA which is not expressed in gingival fibroblasts. In this study, to examine the expression and functional characterization of PDμ22 mRNA and prαein in development and differentiation of periodontal 따sue ， we carried out northem analysis, insitu hybridization, immunofluorescence and immunohistochemistry. The expression of PDLs22 mRNA was increased with PDL cell differentiation from the confluent to multilayer stage but decreased slighdy with mineralized nodule formation in vitro. πle PDLs22 protein was localized on the nuclear membrane and expressed throughout the differentiation of PDL fibroblasts in vitro. The PDLs22 mRNA and protein were expressed in the differentiating cementoblasts, PDL fibroblasts and osteoblasts along the r∞t surface and alveolar bone of the developing rat teeth. These results indicate that the PDLs22 plays an irnportant role in the differentiation of cementoblasts and osteoblasts and thus homeostasis of cementum, PDL and alveolar bone.