Carbamazepine-Induced Systemic Lupus Erythematosus in a Patient With Idiopathic Trigeminal Neuralgia: A Case Report

A 50-year-old woman presented with a mandibular second molar and facial pain and was diagnosed with idiopathic trigeminal neuralgia. Carbamazepine (CBZ) was initiated at 300 mg/day, successfully relieving the pain. However, on the 8th day of CBZ treatment, the patient developed symptoms resembling those of systemic lupus erythematosus with malaise, nausea, and facial erythema. CBZ was immediately discontinued. Subsequently, she experienced numbness in both lower limbs and mild fever, which resolved within a few days. Laboratory tests revealed leukopenia (2.8 × 103/μL), elevated C-reactive protein levels (0.46 mg/dL), and the presence of antinuclear antibodies (ANA) and anti-Sjögren's syndrome-related antigen A antibodies. The clinical course suggested CBZ-induced drug-induced lupus erythematosus (DILE). This case highlights the possibility of DILE onset even after short-term CBZ treatment, the importance of prompt discontinuation of the causative drug in patients suspected of DILE, and the conduct of ANA testing in diagnosing DILE.

Er:YAG laser-assisted comprehensive periodontal pocket therapy for residual periodontal pocket treatment: A randomized controlled clinical trial

BACKGROUND

This study evaluated the effectiveness of a novel pocket therapy (Er:YAG laser-assisted comprehensive periodontal pocket therapy [Er-LCPT]) for residual pocket treatment, compared with conventional mechanical treatment alone, in a randomized controlled clinical trial.

METHODS

Two sites in 18 patients having residual periodontal pockets of ≥5 mm depth, extant following initial active therapy, or during supportive therapy, were randomized into two groups in a split mouth design: the control group received scaling and root planing (SRP) by curette, and the test group received Er-LCPT using curette and laser. With Er-LCPT, after root debridement, inflamed connective tissue on the inner gingival surface and on the bone surface/within extant bone defects was thoroughly debrided. Furthermore, removal of proximate oral epithelium and coagulation of the blood clot in the pocket entrance were performed with laser. Clinical parameters were evaluated, before and after treatment, through 12 months.

RESULTS

Both groups showed significant improvements in clinical parameters. With Er-LCPT, pocket debridement was thoroughly and safely performed, without any adverse side effects and complications, and favorable healing was observed in most of the cases. At 12 months, Er-LCPT demonstrated significantly higher probing pocket depth reduction (2.78 mm vs. 1.89 mm on average; p = 0.012, Wilcoxon signed-rank test), clinical attachment gain (1.67 mm vs. 1.06 mm; p = 0.004) as primary outcomes, and reduced BOP value (0.89 vs. 0.56; p = 0.031), compared with SRP alone.

CONCLUSION

The results of this study indicate that Er-LCPT is more effective for residual pocket treatment, compared with SRP alone.

Associations between Periodontal Status and Liver Function in the Japanese Population: A Cross-Sectional Study

A relationship between periodontitis and liver function has been suggested. Indeed, patients with severe periodontal disease have been found to be more prone to liver dysfunction. The periodontal inflammatory surface area (PISA) has been shown to be a useful indicator of periodontal and systemic diseases. However, little information is available regarding whether the PISA is associated with liver function markers, such as gamma-glutamyltransferase (GGT), aspartate aminotransferase (AST), and alanine aminotransferase (ALT). This study aimed to clarify relationship between liver function markers, AST, ALT, and GGT, and PISA level in a cross-sectional study. The subjects were recruited between 2018 and 2021 at the Medical and Dental Collaboration Center of Kanagawa Dental College Hospital. A periodontal clinical examination was performed, and the PISA was calculated. Peripheral blood samples were collected, and serum levels of liver function markers were measured. The levels of liver function markers were examined in different values of PISA. Participants with high PISA scores were more likely to have increased GGT levels while AST and ALT were not changed with PISA. Increased GGT was found in 10.8% and 29.4% (p = 0.0056), increased AST in 48.2% and 52.9% (p = 0.62), and increased ALT in 35.2% and 47.0% (p = 0.20) among <300 mm² and ≧300 mm² PISA groups, respectively. It was found that males with a PISA of 300 mm² or higher had an elevated level of serum GGT. In conclusion, elevated GGT was found in the high PISA group, particularly in males, while AST and ALT did not differ by PISA.

Influence of Meal Sequence and Number of Teeth Present on Nutrient Intake Status: A Cross-Sectional Study

Intake of fiber, as well as protein, and lipid preloading help to control postprandial glycemic elevation in people with type 2 diabetes and in healthy individuals. However, there are few studies on the awareness of meal sequence and nutrient intake status that consider oral conditions. This cross-sectional study aimed to determine the effects of meal sequences on nutrient intake status and whether these relationships were related to the number of teeth present. The subjects were recruited from the Medical and Dental Collaboration Center of Kanagawa Dental University Hospital between 2018 and 2021. Medical and dental examinations were performed, and a questionnaire was used to determine whether the diet consisted of vegetables, meat or fish, and carbohydrates in that order. Nutrient intake status was assessed using the brief-type self-administered diet history questionnaire. Data were collected from 238 participants. The group with awareness of meal sequence ingested increased nutrients such as n-3 fatty acids, total dietary fiber, calcium, and vitamin C. Saturated fatty acid intake increased in those with fewer teeth, while it was not significantly related to meal sequence. In conclusion, our results showed that meal sequence was associated with nutrient intake status. In addition, the intake of saturated fatty acids increased when many teeth were lost, regardless of meal sequence.

Effect of Locally Delivered Minocycline on the Profile of Subgingival Bacterial Genera in Patients with Periodontitis: A Prospective Pilot Study

This prospective pilot study aimed to evaluate the effect of minocycline-HCl ointment (MO), locally delivered as an adjunct to scaling and root planing (SRP), on subgingival microflora. A total of 59 periodontitis patients received SRP as an initial periodontal therapy. In the selected periodontal pockets with probing depths (PD) of 6−9 mm, the sites that exhibited a positive reaction following a bacterial test using an immunochromatographic device were subsequently treated with MO (SRP + MO group, n = 25). No additional treatment was performed at sites showing a negative reaction (SRP group, n = 34). In addition to subgingival plaque sampling, measurement of clinical parameters including PD, clinical attachment level (CAL), bleeding on probing (BOP), plaque index and gingival index (GI) were performed at baseline and 4 weeks after the initial periodontal therapy. The subgingival microflora were assessed by terminal restriction fragment-length polymorphism analysis. Relative to baseline values, the mean scores for PD-, CAL-, BOP-, and GI-sampled sites were significantly decreased post treatment in both groups (p < 0.01). The intra-comparisons showed a significant decrease in the counts of the genera Eubacterium, Parvimonas, Filifactor, Veillonella, Fusobacterium, Porphyromonas, Prevotella, and unknown species in the SRP + MO group (p < 0.05). Inter-comparisons indicated a significant decrease in the genera Veillonella in the SRP + MO group (p = 0.01). Combination therapy of SRP and local MO induced a change in the subgingival microbial community: particularly, the number of Veillonella spp. was markedly reduced.

Angiogenic Effects of Secreted Factors from Periodontal Ligament Stem Cells

Periodontal disease is a chronic inflammation of tooth-supporting tissues, and the destruction of these tissues results in tooth loss. Regeneration of periodontal tissues is the ultimate goal of periodontal treatment. We previously reported that transplantation of conditioned medium (CM) of periodontal ligament stem cells (PDLSCs) demonstrated the enhancement of periodontal tissue regeneration, compared to CM from fibroblasts (Fibroblast-CM). We hypothesized that the angiogenic effects of PDLSC-CM might participate in the enhanced wound healing of periodontal tissues. The aim of this study was to investigate the effect of PDLSC-CM on the functions of endothelial cells. PDLSCs were cultured from periodontal ligament tissues obtained from healthy volunteers. Human gingival epithelial cells, dermal fibroblasts, osteoblasts, and umbilical vein endothelial cells (HUVECs) were purchased from commercial sources. The functions of endothelial cells were examined using immunostaining of Ki67, observation of nuclear fragmentation and condensation (apoptosis), and network formation on Matrigel. Vascular endothelial cell growth factor (VEGF) level was measured using an ELISA kit. HUVECs demonstrated higher cell viability in PDLSC-CM when compared with those in Fibroblast-CM. HUVECs demonstrated a higher number of Ki67-positive cells and lower apoptosis cells in PDLSC-CM, compared to Fibroblast-CM. Additionally, HUVECs formed more capillary-like structures in PDLSC-CM than Fibroblast-CM. PDLSC-CM contained higher levels of angiogenic growth factor, VEGF, than Fibroblast-CM. Our results showed that PDLSC-CM increased cell viability, proliferation, and capillary formation of HUVECs compared to Fibroblast-CM, suggesting the angiogenic effects of PDLSC-CM, and the effect is a potential regenerative mechanism of periodontal tissues by PDLSC-CM.

Periodontal Tissue Healing After Autologous Tooth Transplantation: A Retrospective Analysis of Case Series

PURPOSE

Tooth transplantation is a treatment that uses non-functional teeth to compensate for defects caused by tooth extractions. Surgical procedures have yielded high success rates in autologous tooth transplantation using a tooth with a complete root. This study aimed to evaluate periodontal tissue healing after transplantation of 14 molar teeth.

MATERIALS AND METHODS

Fourteen individuals aged 28-53 years who underwent autologous transplantation of third molars with completely developed roots between December 2010 and March 2017 were included in the study. The donor tooth was carefully extracted, placed into the prepared transplant site, and stabilised with an orthodontic wire and 4-0 silk sutures for a few weeks. Endodontic treatment was performed after 3-4 weeks. To evaluate the periodontal tissue healing, clinical measurements of the probing pocket depth (PPD), clinical attachment level (CAL), and keratinised gingival width (KGW) were performed, along with radiographic examinations of bone defect fill (BDF) at baseline and at 6 and 12 months after surgery. Statistical analysis was performed using the Mann-Whitney U test.

RESULTS

The changes in PPD and CAL at baseline, 6, and 12 months were statistically significant (P <0.05). KGW did not show a statistically significant decrease. The postoperative-BDF amount at 6 and 12 months was 2.2 ± 1.4 and 4.2 ± 1.4 mm, respectively.

CONCLUSION

Periodontal tissue healing may occur in tooth autotransplantation even in the presence of complete root development in the donor tooth.

A Novel, Tumor-Induced Osteoclastogenesis Pathway Insensitive to Denosumab but Interfered by Cannabidiol

Bone metabolism is strictly regulated, and impaired regulation caused by hormonal imbalances induces systemic bone loss. Local bone loss caused by tumor invasion into bone is suggested to be induced by the generation of cytokines, which affect bone metabolism, by tumor cells. The major cause of systemic and local bone losses is excess bone resorption by osteoclasts, which differentiate from macrophages by receptor activator of nuclear factor kappa-B ligand (RANKL) or tumor necrosis factor-alpha (TNF-α). We previously found a novel pathway for tumor-induced osteoclastogenesis targeting osteoclast precursor cells (OPCs). Tumor-induced osteoclastogenesis was resistant to RANKL and TNF-α inhibitors. In the present study, we confirmed that exosomes derived from oral squamous cell carcinoma (OSCC) cells induced osteoclasts from OPCs. We also showed that the depletion of exosomes from culture supernatants of OSCC cells partially interfered with osteoclastogenesis, and cannabidiol, an innoxious cannabinoid without psychotropic effects, almost completely suppressed tumor-induced osteoclastogenesis. Osteoclastogenesis and its interference by cannabidiol were independent of the expression of nuclear factor of T cell c1 (NFATc1). These results show that osteoclastogenesis induced by OSCC cells targeting OPCs is a novel osteoclastogenic pathway independent of NFATc1 expression that is partially caused by tumor-derived exosomes and suppressed by cannabidiol.

Spontaneous differentiation of periodontal ligament stem cells into myofibroblast during ex vivo expansion

Periodontitis is characterized by the chronic inflammation and destruction of tooth-supporting tissues. Periodontal ligament stem cell (PDLSC) is the mesenchymal stem cell (MSC) population isolated from periodontal ligament, which is the key tissue for regeneration of periodontal tissues. Although transplantation of PDLSCs is proposed as novel regenerative therapy, limited information is available, regarding the characteristic change of PDLSCs during ex vivo expansion. In this study, we encountered morphological change of PDLSCs during standard cell culture and aimed to investigate the change of PDLSCs in stem cell characteristics and to search for the culture condition to maintain stem cell properties. Characteristics of PDLSCs were examined using in vitro osteoblast and adipocyte differentiation. Myofibroblast differentiation was confirmed using immunohistochemistry and collagen gel contraction assay. Replicative senescence was examined by β-gal staining. PDLSCs changed their morphology from spindle to flat and wide during ex vivo expansion. After the morphological change, PDLSCs showed several features of myofibroblast including extensive stress fiber formation, contraction activity, and myofibroblast marker expression. Upon the morphological change, osteoblastic and adipocyte differentiation capacity were reduced and expression of stem cell-related genes were decreased. β-Gal staining was not always correlated with the morphological change of PDLSCs. Moreover, exogenous addition of bFGF and PDGF-BB served to maintain spindle shape and osteoblastic differentiation potential of PDLSCs. This study demonstrates that spontaneous differentiation of PDLSCs during ex vivo expansion and may provide the important information of cell culture condition of PDLSCs for clinical use.

Evaluation of bone healing following Er:YAG laser ablation in rat calvaria compared with bur drilling

The Er:YAG laser is currently used for bone ablation. However, the effect of Er:YAG laser irradiation on bone healing remains unclear. The aim of this study was to investigate bone healing following ablation by laser irradiation as compared with bur drilling. Rat calvarial bone was ablated using Er:YAG laser or bur with water coolant. Er:YAG laser effectively ablated bone without major thermal changes. In vivo micro-computed tomography analysis revealed that laser irradiation showed significantly higher bone repair ratios than bur drilling. Scanning electron microscope analysis showed more fibrin deposition on laser-ablated bone surfaces. Microarray analysis followed by gene set enrichment analysis revealed that IL6/JAK/STAT3 signaling and inflammatory response gene sets were enriched in bur-drilled bone at 6 hours, whereas the E2F targets gene set was enriched in laser-irradiated bone. Additionally, Hspa1a and Dmp1 expressions were increased and Sost expression was decreased in laser-irradiated bone compared with bur-drilled bone. In granulation tissue formed after laser ablation, Alpl and Gblap expressions increased compared to bur-drilled site. Immunohistochemistry showed that osteocalcin-positive area was increased in the laser-ablated site. These results suggest that Er:YAG laser might accelerate early new bone formation with advantageous surface changes and cellular responses for wound healing, compared with bur-drilling.

Cell transfer technology for tissue engineering

We recently developed novel cell transplantation method “cell transfer technology” utilizing photolithography. Using this method, we can transfer ex vivo expanded cells onto scaffold material in desired patterns, like printing of pictures and letters on a paper. We have investigated the possibility of this novel method for cell-based therapy using several disease models. We first transferred endothelial cells in capillary-like patterns on amnion. The transplantation of the endothelial cell-transferred amnion enhanced the reperfusion in mouse ischemic limb model. The fusion of transplanted capillary with host vessel networks was also observed. The osteoblast- and periodontal ligament stem cell-transferred amnion were next transplanted in bone and periodontal defects models. After healing period, both transplantations improved the regeneration of bone and periodontal tissues, respectively. This method was further applicable to transfer of multiple cell types and the transplantation of osteoblasts and periodontal ligament stem cell-transferred amnion resulted in the improved bone regeneration compared with single cell type transplantation. These data suggested the therapeutic potential of the technology in cell-based therapies for reperfusion of ischemic limb and regeneration of bone and periodontal tissues. Cell transfer technology is applicable to wide range of regenerative medicine in the future.

Exosomes of human placenta-derived mesenchymal stem cells stimulate angiogenesis

BACKGROUND

The therapeutic potential of mesenchymal stem cells (MSCs) may be attributed partly to humoral factors such as growth factors, cytokines, and chemokines. Human term placental tissue-derived MSCs (PlaMSCs), or conditioned medium left over from cultures of these cells, have been reported to enhance angiogenesis. Recently, the exosome, which can transport a diverse suite of macromolecules, has gained attention as a novel intercellular communication tool. However, the potential role of the exosome in PlaMSC therapeutic action is not well understood. The purpose of this study was to evaluate PlaMSC-derived exosome angiogenesis promotion in vitro and in vivo.

METHODS

MSCs were isolated from human term placental tissue by enzymatic digestion. Conditioned medium was collected after 48-h incubation in serum-free medium (PlaMSC-CM). Angiogenic factors present in PlaMSC-CM were screened by a growth factor array. Exosomes were prepared by ultracentrifugation of PlaMSC-CM, and confirmed by transmission electron microscopy, dynamic light scattering, and western blot analyses. The proangiogenic activity of PlaMSC-derived exosomes (PlaMSC-exo) was assessed using an endothelial tube formation assay, a cell migration assay, and reverse transcription-PCR analysis. The in-vivo angiogenic activity of PlaMSC-exo was evaluated using a murine auricle ischemic injury model.

RESULTS

PlaMSC-CM contained both angiogenic and angiostatic factors, which enhanced endothelial tube formation. PlaMSC-exo were incorporated into endothelial cells; these exosomes stimulated both endothelial tube formation and migration, and enhanced angiogenesis-related gene expression. Laser Doppler blood flow analysis showed that PlaMSC-exo infusion also enhanced angiogenesis in an in-vivo murine auricle ischemic injury model.

CONCLUSIONS

PlaMSC-exo enhanced angiogenesis in vitro and in vivo, suggesting that exosomes play a role in the proangiogenic activity of PlaMSCs. PlaMSC-exo may be a novel therapeutic approach for treating ischemic diseases.

Conditioned Medium from Periodontal Ligament Stem Cells Enhances Periodontal Regeneration

Periodontal disease is one of the most common infectious diseases in adults and is characterized by the destruction of tooth-supporting tissues. Mesenchymal stem cells (MSCs) comprise the mesoderm-originating stem cell population, which has been studied and used for cell therapy. However, because of the lower rate of cell survival after MSC transplantation in various disease models, paracrine functions of MSCs have been receiving increased attention as a regenerative mechanism. The aim of this study was to investigate the regenerative potential of transplanted conditioned medium (CM) obtained from cultured periodontal ligament stem cells (PDLSCs), the adult stem cell population in tooth-supporting tissues, using a rat periodontal defect model. Cell-free CM was collected from PDLSCs and fibroblasts, using ultrafiltration and transplanted into surgically created periodontal defects. Protein content of CM was examined by antibody arrays. Formation of new periodontal tissues was analyzed using microcomputed tomography and histological sections. PDLSC-CM transplantation enhanced periodontal tissue regeneration in a concentration-dependent manner, whereas fibroblast-CM did not show any regenerative function. Proteomic analysis revealed that extracellular matrix proteins, enzymes, angiogenic factors, growth factors and cytokines were contained in PDLSC-CM. Furthermore, PDLSC-CM transplantation resulted in the decreased mRNA level of tumor necrosis factor-α (TNF-α) in healing periodontal tissues. In addition, we found that PDLSC-CM suppressed the mRNA level of TNF-α in the monocyte/macrophage cell line, RAW cells, stimulated with IFN-γ. Our findings suggested that PDLSC-CM enhanced periodontal regeneration by suppressing the inflammatory response through TNF-α production, and transplantation of PDLSC-CM could be a novel approach for periodontal regenerative therapy.

Neuroprotective effects of human umbilical cord-derived mesenchymal stem cells on periventricular leukomalacia-like brain injury in neonatal rats

Background

Periventricular leukomalacia (PVL) is a type of multifactorial brain injury that causes cerebral palsy in premature infants. To date, effective therapies for PVL have not been available. In this study, we examined whether mesenchymal stem cells (MSCs) possess neuroprotective property in a lipopolysaccharide (LPS)-induced neonatal rat PVL-like brain injury.

Methods

Human umbilical cord-derived MSCs (UCMSCs) were used in this study. Four-day-old rats were intraperitoneally injected with LPS (15 mg/kg) to cause the PVL-like brain injury and were treated immediately after the LPS-injection with UCMSCs, conditioned medium prepared from MSCs (UCMSC-CM) or interferon-gamma (IFN-γ)-pretreated MSC (IFN-γ-UCMSC-CM). To assess systemic reaction to LPS-infusion, IFN-γ in sera was measured by ELISA. The brain injury was evaluated by immunostaining of myelin basic protein (MBP) and caspase-3. RT-PCR was used to quantitate pro-inflammatory cytokine levels in the brain injury, and the expression of tumor necrosis factor-stimulated gene-6 (TSG-6) or indoleamine 2,3-dioxygenase (IDO) to evaluate anti-inflammatory or immunomodulatory molecules in UCMSCs, respectively. A cytokine and growth factor array was employed to investigate the cytokine secretion profiles of UCMSCs.

Results

Elevated serum IFN-γ was observed in LPS-infused rats. The expression of IL-6, tumor necrosis factor-alpha (TNF-α), IL-1ß, and monocyte chemoattractant protein-1 (MCP-1) were increased in the brain by LPS-infusion in comparison to saline-infused control. LPS-infusion increased caspase-3-positive cells and decreased MBP-positive area in neonatal rat brains. A cytokine and growth factor array demonstrated that UCMSCs secreted various cytokines and growth factors. UCMSCs significantly suppressed IL-1ß expression in the brains and reversed LPS-caused decrease in MBP-positive area. UCMSC-CM did not reverse MBP-positive area in the injured brain, while IFN-γ-UCMSC-CM significantly increased MBP-positive area compared to control (no treatment). IFN-γ-pretreatment increased TSG-6 and IDO expression in UCMSCs.

Conclusion

We demonstrated that bolus intraperitoneal infusion of LPS caused PVL-like brain injury in neonatal rats and UCMSCs infusion ameliorated dysmyelination in LPS-induced neonatal rat brain injury. Conditioned medium prepared from IFN-γ-pretreated UCMSCs significantly reversed the brain damage in comparison with UCMSC-CM, suggesting that the preconditioning of UCMSCs would improve their neuroprotective effects. The mechanisms underline the therapeutic effects of MSCs on PVL need continued investigation to develop a more effective treatment.

High-frequency pulsed low-level diode laser therapy accelerates wound healing of tooth extraction socket: An in vivo study

BACKGROUND AND OBJECTIVE

This study aimed to evaluate the effects of high-frequency pulsed (HiFP) low-level laser therapy (LLLT) on early wound healing of tooth extraction sockets in rats.

STUDY DESIGN/MATERIALS AND METHODS

Bilateral maxillary first molars were extracted from 6-week-old Sprague-Dawley rats. Sockets on the right were treated by HiFP low-level diode laser irradiation (904-910 nm); the left sides served as unirradiated controls. LLLT (0.28 W, 30 kHz, 200-ns pulse, 0.6% duty cycle, 61.2 J/cm² total power density) was employed immediately after extraction and every 24 hours thereafter. The maxillae including the sockets were resected 3 or 7 days after extraction. Soft-tissue healing was evaluated on days 0, 3, and 7. The bone mineral content (BMC), bone volume (BV), and bone mineral density (BMD) of the extraction sockets were evaluated by microcomputed tomography, and histomorphometric analysis was carried out on day 7. Real-time PCR analysis of osteogenic marker expression and immunohistochemical detection of proliferating cell nuclear antigen (PCNA)-positive cells were performed on day 3.

RESULTS

Compared with control sites, the un-epithelialized areas of the extracted sites were significantly reduced by irradiation (P = 0.04), and the BMC, BV, and BMD of laser-treated sites were significantly increased (P = 0.004, 0.006, and 0.009, respectively). On day 7, the mean height of newly formed immature woven bone was higher in laser-treated sites (P = 0.24). On day 3, laser-treated sites showed significantly higher osteocalcin mRNA expression (P = 0.04) and PCNA-positive cell numbers (P = 0.01).

CONCLUSION

HiFP low-level diode laser irradiation enhanced soft- and hard-tissue healing of tooth extraction sockets. Lasers Surg. Med. 48:955-964, 2016. © 2016 Wiley Periodicals, Inc.

Placenta Mesenchymal Stem Cell Derived Exosomes Confer Plasticity on Fibroblasts

Mesenchymal stem cell (MSC)-conditioned medium (MSC-CM) has been reported to enhance wound healing. Exosomes contain nucleic acids, proteins, and lipids, and function as an intercellular communication vehicle for mediating some paracrine effects. However, the function of MSC-derived exosomes (MSC-exo) remains elusive. In this study, we isolated human placenta MSC (PlaMSC)-derived exosomes (PlaMSC-exo) and examined their function in vitro. PlaMSCs were isolated from human term placenta using enzymatic digestion. PlaMSC-exo were prepared from the conditioned medium of PlaMSC (PlaMSC-CM) by ultracentrifugation. The expression of stemness-related genes, such as OCT4 and NANOG, in normal adult human dermal fibroblasts (NHDF) after incubation with PlaMSC-exo was measured by real-time reverse transcriptase PCR analysis (real-time PCR). The effect of PlaMSC-exo on OCT4 transcription activity was assessed using Oct4-EGFP reporter mice-derived dermal fibroblasts. The stimulating effects of PlaMSC-exo on osteoblastic and adipocyte-differentiation of NHDF were evaluated by alkaline phosphatase (ALP), and Alizarin red S- and oil red O-staining, respectively. The expression of osteoblast- and adipocyte-related genes was also assessed by real-time PCR. The treatment of NHDF with PlaMSC-exo significantly upregulated OCT4 and NANOG mRNA expression. PlaMSC-exo also enhanced OCT4 transcription. The NHDF treated with PlaMSC-exo exhibited osteoblastic and adipocyte-differentiation in osteogenic and adipogenic induction media. PlaMSC-exo increase the expression of OCT4 and NANOG mRNA in fibroblasts. As a result, PlaMSC-exo influence the differentiation competence of fibroblasts to both osteoblastic and adipocyte-differentiation. It shows a new feature of MSCs and the possibility of clinical application of MSC-exo. J. Cell. Biochem. 117: 1658-1670, 2016. © 2015 Wiley Periodicals, Inc.

Recruitment of bone marrow-derived cells to periodontal tissue defects

Bone marrow-derived cells (BMCs) are considered to be a major source of mesenchymal stem cells (MSCs) in adults and are known to be effective in periodontal tissue regeneration. However, whether endogenous BMCs are involved in periodontal tissue repair process is uncertain. We therefore created periodontal tissue defects in the buccal alveolar bone of mandibular first molars in bone marrow chimeric mice, and immunohistochemically examined the expression of stromal cell derived factor-1 (SDF-1) and the mobilization of BMCs. We found that SDF-1 expression was increased around the defects at as early as 1 week after injury and that BMCs were mobilized to the defects, while GFP+/CD45+ were rarely observed. Fluorescence-activated cell sorting (FACS) analysis demonstrated that the number of platelet-derived growth factor receptor (pdgfr) α+/Sca-1+ (PαS) cells in the bone marrow decreased after injury. Taken together, these results suggest that BMCs are mobilized to the periodontal tissue defects. Recruitment of BMCs, including a subset of MSCs could be a new target of periodontal treatment.

[Bone and Stem Cells. Mesenchymal stem cells and bone regeneration]

Mesenchymal stem cells (MSCs) have multi-differentiation potency, and enhance wound healing in various kinds of disease. Recently MSC not only differentiate into tissue-forming cells, but also secrete various kinds of cytokines and chemokines that are anti-apoptotic, immunomodulatory, angiogenic, and the cell-mobilizing to influence extracellular environment. In addition, we show that MSC has a novel intercellular communication mechanism. It hopes to suggest ways to make safer and reliable usage of MSC in bone regeneration.

Periodontal regeneration using periodontal ligament stem cell-transferred amnion

Periodontal disease is characterized by the destruction of tooth supporting tissues. Regeneration of periodontal tissues using ex vivo expanded cells has been introduced and studied, although appropriate methodology has not yet been established. We developed a novel cell transplant method for periodontal regeneration using periodontal ligament stem cell (PDLSC)-transferred amniotic membrane (PDLSC-amnion). The aim of this study was to investigate the regenerative potential of PDLSC-amnion in a rat periodontal defect model. Cultured PDLSCs were transferred onto amniotic membranes using a glass substrate treated with polyethylene glycol and photolithography. The properties of PDLSCs were investigated by flow cytometry and in vitro differentiation. PDLSC-amnion was transplanted into surgically created periodontal defects in rat maxillary molars. Periodontal regeneration was evaluated by microcomputed tomography (micro-CT) and histological analysis. PDLSCs showed mesenchymal stem cell-like characteristics such as cell surface marker expression (CD90, CD44, CD73, CD105, CD146, and STRO-1) and trilineage differentiation ability (i.e., into osteoblasts, adipocytes, and chondrocytes). PDLSC-amnion exhibited a single layer of PDLSCs on the amniotic membrane and stability of the sheet even with movement and deformation caused by surgical instruments. We observed that the PDLSC-amnion enhanced periodontal tissue regeneration as determined by micro-CT and histology by 4 weeks after transplantation. These data suggest that PDLSC-amnion has therapeutic potential as a novel cell-based regenerative periodontal therapy.

Gingival tissue healing following Er:YAG laser ablation compared to electrosurgery in rats

The erbium-doped yttrium aluminum garnet (Er:YAG) laser is currently used for periodontal soft tissue management with favorable outcomes. However, the process of wound healing after Er:YAG laser (ErL) treatment has not been fully elucidated yet. The aim of this study was to investigate the gingival tissue healing after ErL ablation in comparison with that after electrosurgery (ElS). Gingival defects were created in 28 rats by ablation with ErL irradiation or ElS. The chronological changes in wound healing were evaluated using histological, histometrical, and immunohistochemical analyses. The ErL-ablated gingival tissue revealed much less thermal damage, compared to the ElS. In the ElS sites, the postoperative tissue destruction continued due to thermal damage, while in the ErL sites, tissue degradation was limited and the defects were re-epithelialized early. Heat shock protein (Hsp) 72/73 expression was detected abundantly remote from the wound in the ElS, whereas it was slightly observed in close proximity to the wound in the ErL sites. Hsp47 expression was observed in the entire connective tissue early in the wound healing and was found limited in the wound area later. This phenomenon proceeded faster in the ErL sites than in the ElS sites. Expression of proliferating cell nuclear antigen (PCNA) persisted in the epithelial tissue for a longer period in the ElS than that in the ErL. The ErL results in faster and more favorable gingival wound healing compared to the ElS, suggesting that the ErL is a safe and suitable tool for periodontal soft tissue management.

Expression of angiogenesis-related factors and inflammatory cytokines in placenta and umbilical vessels in pregnancies with preeclampsia and chorioamnionitis/funisitis

We hypothesized that gene expression in placenta and umbilical vessels are affected by intrauterine environment and some of the expression in umbilical vessels originating from the fetus could reflect fetal condition of these complicated pregnancies. Expression of angiogenesis-related factors and inflammatory cytokines were examined in placenta and umbilical vessels to clarify the effects of intrauterine environment of pregnancies complicated by preeclampsia and chorioamnionitis/funisitis. Forty-six preterm cesarean section deliveries were classified into three groups based on maternal condition during prenatal monitoring: preeclampsia (PE) (n = 11), chorioamnionitis/funisitis (CAM) (n = 8), and preterm control (PC) (n = 27). Angiogenesis-related factors and inflammatory cytokines in placentas, umbilical arteries and umbilical veins were analyzed by RT-PCR and immunohistochemistry. We demonstrated that Ang-2, Tie-2, and Dll4 increase in the placentas of PE compared to PC for the first time, and we confirmed the findings of previous reports showing the high expression of HIF-1α, sFlt-1, endoglin, leptin, and AT1R. Expression of angiogenesis-related factors, including HIF-1α, VEGF, angiopoietin, and TGF-β systems, and inflammatory cytokines, such as TNF-α and IL-6, increased in umbilical vessels of PE. Umbilical veins of CAM showed a higher Dll4 level than did PC. In preeclampsia, abnormal expressions of angiogenesis-related factors related to lifestyle diseases in adulthood were seen in the placenta and umbilical vessels as compared to PC. Chorioamnionitis/funisitis showed only upregulation of DII4 in umbilical veins.

Cell-printing and transfer technology applications for bone defects in mice

Bone regeneration therapy based on the delivery of osteogenic factors and/or cells has received a lot of attention in recent years since the discovery of pluripotent stem cells. We reported previously that the implantation of capillary networks engineered ex vivo by the use of cell-printing technology could improve blood perfusion. Here, we developed a new substrate prepared by coating glass with polyethylene glycol (PEG) to create a non-adhesive surface and subsequent photo-lithography to finely tune the adhesive property for efficient cell transfer. We examined the cell-transfer efficiency onto amniotic membrane and bone regenerative efficiency in murine calvarial bone defect. Cell transfer of KUSA-A1 cells (murine osteoblasts) to amniotic membrane was performed for 1 h using the substrates. Cell transfer using the substrate facilitated cell engraftment onto the amniotic membrane compared to that by direct cell inoculation. KUSA-A1 cells transferred onto the amniotic membrane were applied to critical-sized calvarial bone defects in mice. Micro-computed tomography (micro-CT) analysis showed rapid and effective bone formation by the cell-equipped amniotic membrane. These results indicate that the cell-printing and transfer technology used to create the cell-equipped amniotic membrane was beneficial for the cell delivery system. Our findings support the development of a biologically stable and effective bone regeneration therapy.

Comparison of characteristics of periodontal ligament cells obtained from outgrowth and enzyme-digested culture methods

OBJECTIVE

Periodontal ligament (PDL) cells have an important role in periodontal regeneration. The unique characteristics of PDL cells, mainly outgrown cells derived from PDL tissue, have been investigated. Recently, mesenchymal stem cells have been obtained from PDL tissue using enzyme digestion. The differences in properties of those PDL cells cultured by the two methods (outgrowth and enzyme digestion) are unclear. The objective of this study was to investigate the characteristics of PDL cells obtained by these methods.

METHODS

PDL cells from extracted tooth were cultured using outgrowth and enzyme digest methods. Cell proliferation, colony-forming activity and differentiation capacity to osteoblast, adipocyte and chondrocyte were compared. Gene expressions for PDL cells, mesenchymal stem cells and fibroblasts were also investigated by reverse transcription polymerase chain reaction. Procollagen type I c-peptide (PIP) production was measured using an enzyme-linked immunosorbent assay (ELISA) kit.

RESULTS

PDL cells cultured by enzyme digest methods showed a higher proliferation rate, colony-forming activity and differentiation capacity into osteoblast, adipocyte and chondrocyte than those in PDL cells by outgrowth method. CD166, one of the mesenchymal stem cell markers, was slightly higher in enzyme-digested PDL than in outgrowth PDL, whilst gene expressions for type 1 collagen alpha 1 and type 3 collagen were higher in outgrown PDL cells. Moreover, outgrowth PDL exhibited higher PIP production than enzyme-digested PDL cells.

CONCLUSION

PDL cells obtained by outgrowth and enzyme digestion showed different characteristics. The enzyme digestion method yielded cells with higher proliferation rate and mesenchymal stem cell-like properties, whereas cells with fibroblast-like properties were collected in the outgrowth method. PDL cell properties by different culture methods may provide information for inventing new therapeutic uses of PDL cells.

Therapeutic angiogenesis by implantation of a capillary structure constituted of human adipose tissue microvascular endothelial cells

OBJECTIVE

We previously reported a novel technology for the engineering of a capillary network using an optical lithographic technique. To apply this technology to the therapy of ischemic diseases, we tested human omental microvascular endothelial cells (HOMECs) as an autologous cell source and decellularized human amniotic membranes (DC-AMs) as a pathogen-free and low immunogenic transplantation scaffold.

METHODS AND RESULTS

Human umbilical vein endothelial cells were aligned on a patterned glass substrate and formed a capillary structure when transferred onto an amniotic membrane (AM). In contrast, HOMECs were scattered and did not form a capillary structure on AMs. Treatment of HOMECs with sphingosine 1-phosphate (S1P) inhibited HOMEC migration and enabled HOMEC formation of a capillary structure on AMs. Using quantitative RT-PCR and Western blot analyses, we demonstrated that the main S1P receptor in HOMECs is S1P(2), which is lacking in human umbilical vein endothelial cells, and that inhibition of cell migration by S1P is mediated through an S1P(2)-Rho-Rho-associated kinase signaling pathway. Implantation of capillaries engineered on DC-AMs into a hindlimb ischemic nude mouse model significantly increased blood perfusion compared with controls.

CONCLUSIONS

A capillary network consisting of HOMECs on DC-AMs can be engineered ex vivo using printing technology and S1P treatment. This method for regeneration of a capillary network may have therapeutic potential for ischemic diseases.

Alpha2-adrenoceptors coordinate swallowing and respiration

Because the discoordination between swallowing and respiration may cause severe respiratory disorders such as aspiration pneumonia, understanding the neuronal mechanisms underlying such coordination is important. Recently, it was reported that medullary noradrenergic neurons are involved in evoking esophageal-gastric relaxation reflex, leading to a hypothesis that such neurons are also involved in swallowing-respiration coordination. We tested this hypothesis using an in vitro brain-stem preparation obtained from neonatal rats. A temporal inhibition of respiratory rhythm was consistently observed when swallowing activity was induced by electrical stimulations to the supralaryngeal nerve. We found that a broad adrenergic receptor agonist, norepinephrine, markedly blocked the swallowing-induced temporal inhibition of respiration. Further studies revealed that swallowing-induced respiratory inhibition is blocked by an alpha2-adrenergic receptor agonist and enhanced by an alpha2-adrenergic receptor antagonist, indicating an important role of alpha2-adrenergic receptors in regulation of the coordination between swallowing and respiration in vitro.

IL-6 Induces Osteoblastic Differentiation of Periodontal Ligament Cells

Interleukin (IL)-6 has been considered as an osteolytic factor involved in periodontal disease. However, the function of IL-6 in osteoblastic differentiation of periodontal ligament cells is not clear. We examined the effects of IL-6 and its soluble receptor (sIL-6R) on osteoblastic differentiation of periodontal ligament cells. Osteoblastic differentiation was induced by ascorbic acid. Osteoblast markers, including alkaline phosphatase activity and Runx2 gene expression, were examined. The mechanism of action of IL-6 on osteoblastic differentiation was evaluated by insulin-like growth factor (IGF)-I production and specific inhibitors for the IL-6-signaling molecule. IL-6/sIL-6R enhanced alkaline phosphatase activity and Runx2. Alkaline phosphatase activity was reduced by anti-IGF-I antibody. Mitogen-activated protein kinase and Janus protein tyrosine kinase inhibitors diminished alkaline phosphatase induced by IL-6/sIL-6R. We conclude that IL-6/sIL-6R increases ascorbic-acid-induced alkaline phosphatase activity through IGF-I production, implying that IL-6 acts not only as an osteolytic factor, but also as a mediator of osteoblastic differentiation in periodontal ligament cells.

Isolation of multipotent stem cells from adult rat periodontal ligament by neurosphere-forming culture system

Adult multipotent stem cells have been isolated from various non-neural tissues. Here, we report the isolation of multipotent stem cells from rat periodontal ligament (PDL) using neurosphere-forming culture system. Enzymatically dissociated PDL cells were cultured in serum-free basal medium containing EGF, bFGF, and LIF. Free-floating spheres expressing nestin, GFAP, and vimentin were formed by 7 days of the culture. In addition, spheres expressed mRNA of neural crest-associated transcription factors Twist, Slug, Sox2, and Sox9. PDL-derived spheres differentiated into multinucleated myotubes, NFM-positive neuron-like cells, GFAP-positive astrocyte-like cells and CNPase-positive oligodendrocyte-like cells. Methylcellulose colony-forming assay revealed that a single PDL cell could form a sphere at a frequency of approximately 0.01% of total cells. These data indicate that PDL-derived spheres contained multipotent adult stem cells capable of differentiating into both neural and mesodermal progeny. This is the first report of the isolation of PDL-derived stem cells with primitive neural crest stem cell features.

Cyclooxygenase-2-dependent prostaglandin E(2) upregulates interleukin (IL)-1alpha-induced IL-6 generation in mouse cementoblasts

BACKGROUND

Prostaglandin E(2) (PGE(2)), which exerts its biologic actions via EP receptors (EP(1), EP(2), EP(3,) and EP(4)), is a bioactive metabolite of arachidonic acid that is produced by cyclooxygenase (COX)-1 and/or COX-2. In the present study, we investigated whether a mouse cementoblast cell line, OCCM-30 cells, that was stimulated with interleukin (IL)-1alpha produced COX-2-dependent PGE(2) and whether the produced PGE(2) affected IL-1alpha-induced IL-6 production.

METHODS

OCCM-30 cells were stimulated with vehicle or IL-1alpha in the presence or absence of indomethacin (a COX-1/COX-2 inhibitor), NS-398 (a specific COX-2 inhibitor), PGE(2), and EP receptor agonists. PGE(2) and IL-6 levels were assayed by enzyme linked immunosorbent assay.

RESULTS

IL-1alpha induced PGE(2) production in a time-dependent fashion. Indomethacin and NS-398 completely inhibited IL-1alpha-induced PGE(2) production. 17-phenyl-omega-trinor PGE(2) (an EP(1) agonist) and an EP(4) agonist mimicked PGE(2) enhancement of IL-1alpha-induced IL-6 production in OCCM-30 cells.

CONCLUSIONS

From these data, we suggest that IL-1alpha induced PGE(2) production in a COX-2-dependent manner in OCCM-30 cells and that the COX-2-derived PGE(2) upregulates IL-1alpha-elicited IL-6 production via EP(1) and/or EP(4) receptors. PGE(2) and IL-6 produced by cementoblasts may be involved in the pathogenesis of periodontal disease.

Extracellular Signal-Regulated Kinase 1/2 Is Involved in Ascorbic Acid–Induced Osteoblastic Differentiation in Periodontal Ligament Cells

BACKGROUND

Periodontal ligament (PDL) cells possess osteoblast-like properties and play key roles in periodontal regeneration. Previously, we have reported that ascorbic acid promotes the osteoblastic differentiation of PDL cells by modulating the type I collagen-integrin interaction. However, the signaling pathway activated following collagen-integrin interaction is still unclear. In this study, we examined the involvement of extracellular signal-regulated kinase (ERK)1/2 in the expression of osteoblastic marker genes such as the osteoblast-specific transcriptional factor runt-related transcription factor 2 (Runx2), alkaline phosphatase (ALP), and osteocalcin (OCN) in PDL cells.

METHODS

PDL cells were cultured on a conventional or type I collagen-coated dish in the presence or absence of ascorbic acid and examined for ALP activity and osteoblastic marker genes. For detection of ERK1/2, cells were plated on a petri (non-adhesive) dish or type I collagen-coated dish, and Western blot analysis was performed. The effect of the ERK1/2 inhibitor on osteoblastic marker gene expression was examined.

RESULTS

Ascorbic acid increased gene expression of Runx2, ALP, and OCN. A combination of ascorbic acid and type I collagen remarkably upregulated Runx2, ALP, and OCN gene expression and ALP activity. Western blot analysis revealed an increased level of ERK1/2 phosphorylation in cells plated on type I collagen. An ERK1/2 inhibitor suppressed ascorbic acid-induced ALP and OCN gene expression, whereas Runx2 was not affected in PDL cells.

CONCLUSION

These results indicate that ERK1/2 is involved in ascorbic acid-induced osteoblastic differentiation during PDL cell attachment to type I collagen.

Twist negatively regulates osteoblastic differentiation in human periodontal ligament cells

Periodontal ligament (PDL) is a thin fibrous connective tissue located between two mineralized tissues, alveolar bone and cementum, which maintains a constant width physiologically. The mechanisms by which PDL resists mineralization are not well understood. Twist is a basic helix loop helix protein that plays a central role in regulation of early osteogenesis. We investigated the localization of Twist in PDL and compared the expression of Twist and osteoblast-related genes in PDL cells with those in osteoblast-like cells in the presence or absence of recombinant human bone morphogenetic protein (BMP)-2. Histochemical analysis showed that Twist was expressed along alveolar bone surface in PDL. PDL cells constitutively expressed Twist gene and the expression level was higher than that in osteoblast-like cells. In osteoblast-like cell culture, BMP-2 enhanced osteoblast-related gene expression, while Twist expression was slightly decreased. In contrast, BMP-2 increased runt-related transcription factor (Runx)-2, but failed to enhance alkaline phosphatase (ALP) and osteocalcin (OCN) gene expression in PDL cells. Interestingly, unlike in osteoblast-like cells, Twist expression was upregulated by BMP-2 in PDL cells. We transiently knocked down Twist gene in PDL cells using a short interference RNA expression vector (siTwist) and found that ALP, osteopontin (OPN), bone sialoprotein (BSP) genes expression and basal level of ALP activity were slightly increased, whereas Runx2 and OCN genes were not affected. Collectively, these results suggest that Twist may act as a negative regulator of osteoblastic differentiation in PDL cells.

Stem cell properties of human periodontal ligament cells

BACKGROUND AND OBJECTIVE

Stem cells have been used for regenerative therapies in various fields. The proportion of cells that possess stem cell properties in human periodontal ligament (PDL) cells is not yet well understood. In this study, we quantitatively characterized human PDL cells to clarify their stem cell properties, including self-renewal, multipotency, and stem cell marker expression.

MATERIAL AND METHODS

PDL cells were obtained from extracted premolar or wisdom teeth, following which a proliferation assay for self-renewal, a differentiation assay for multipotency, immunostaining for STRO-1, and fluorescence-activated cell sorter (FACS) analysis for stem cell markers (including CD105, CD166, and STRO-1) were performed.

RESULTS

Approximately 30% of 400 PDL cells were found to possess replicative potential and formed single-cell colonies, and 30% of these colonies displayed positive staining for STRO-1, 20% differentiated into adipocytes and 30% differentiated into osteoblasts. FACS analysis revealed that PDL cells, including cell populations, expressed the stem cell markers CD105, CD166, and STRO-1.

CONCLUSION

The findings of this study indicated that PDL cells possess crucial stem cell properties, such as self-renewal and multipotency, and express the mesenchymal stem cell markers CD105, CD166, and STRO-1 on their cell surface, although there were some variations. Thus, PDL cells can be used for periodontal regenerative procedures.

Dental hygiene education in Japan: present status and future directions

The aim of this report is to provide basic information about the historical development, current status and future needs of education and training of dental hygienists in Japan. The first formal training of dental hygienists in Japan started at Tokyo in 1949. Restructure and modification of the dental hygiene education system has been reiterated over the years in order to satisfy the needs of the constantly changing society. Although previously only vocational training was provided for dental hygienists, higher-level education has been conducted. The present legislation of dental hygiene has gone through a complicated process. The student should take the dental hygienist licensing examination which is held once a year by the National Board organized by the Ministry of Health, Labour and Welfare. Currently there are 136 dental hygiene schools and the total enrolment is about 7000. The duration of dental hygiene education course has been prolonged from 2 to 3 years since 2001. In 2004, the 4-year course started. The 2-year dental hygiene education program is expected to be replaced with the 3- and 4-year courses by 2010. The dental hygiene education system in Japan will be improved in many ways as dental hygienists are expected to participate in health promotion and preventive care, and to gain knowledge of the economics and organization of health care in relation to oral hygiene.

Application of periodontal ligament cell sheet for periodontal regeneration: a pilot study in beagle dogs

OBJECTIVE

The ultimate goal of periodontal treatment is to regenerate the damaged periodontal support. Although periodontal ligament (PDL) cells are essential for periodontal regeneration, few studies have reported the transplantation of periodontal ligament cells to periodontal defects. We developed a new method to apply periodontal ligament cells as a sheet to the defect. The aim of this study was to investigate the periodontal healing after application of the periodontal ligament cell sheet in beagle dogs.

METHODS

Autologous periodontal ligament cells were obtained from extracted premolars of each beagle dog. Periodontal ligament cell sheets were fabricated using a temperature-responsive cell culture dish. Dehiscence defects were surgically created on the buccal surface of the mesial roots of bilateral mandibular first molars of each dog. In the experimental group (five defects), periodontal ligament cell sheet with reinforced hyaluronic acid carrier was applied to the defect. Only the hyaluronic acid carrier was applied to the contralateral side as a control (five defects). Eight weeks after surgery, the animals were sacrificed and decalcified specimens were prepared. Healing of the periodontal defects was evaluated histologically and histometrically.

RESULTS

No clinical signs of inflammation or recession of gingiva were observed in both experimental and control groups. In the experimental group, periodontal tissue healing with bone, periodontal ligament and cementum formation was observed in three out of five defects. In the control group, such periodontal tissue formation was not observed except in one defect. Histometric analysis revealed that the formation of new cementum in the experimental group was significantly higher than that in the control group.

CONCLUSION

The periodontal ligament cell sheet has a potential to regenerate periodontal tissue and may become a novel regenerative therapy.

S100A4 inhibition by RNAi up-regulates osteoblast related genes in periodontal ligament cells

Periodontal ligament (PDL) is a thin fibrous connective tissue located between alveolar bone and cementum that remains unmineralized physiologically. It is thus thought that PDL cells possess mechanisms to inhibit mineralization. It has been demonstrated that S100A4, a member of the S100 calcium-binding protein family, is synthesized and secreted by PDL cells, and that it may act as an inhibitor of mineralization. However, the mechanisms of action of S100A4 in mineralization have not been thoroughly clarified. In the present study we investigated the effects of S100A4 inhibition by a short interfering RNA (siRNA) on the expression of osteoblast related genes by human PDL cells. Inhibition of S100A4 by siRNA resulted in increased expression of osteoblastic markers such as osteopontin and osteocalcin, and the osteoblast-specific transcription factors, Runx2/Cbfa1 and Osterix. These results indicate that S100A4 suppresses the expression of osteoblastic genes in PDL cells and may thus inhibit mineralization in the PDL.

Role of Ascorbic Acid in Periodontal Ligament Cell Differentiation

BACKGROUND

Periodontal ligament (PDL) cells form mineralized nodules in vitro. Ascorbic acid is known to be required in this process, although its effect on osteoblastic differentiation of PDL cells remains unclear. The purpose of this study was to determine the role of ascorbic acid on the early osteoblastic differentiation of PDL cells, with regard to alkaline phosphatase (ALP) activity, type I collagen production and integrin expression.

METHODS

Cultured PDL cells were stimulated at confluence with ascorbic acid in the presence or absence of type I collagen inhibitor and blocking antibodies to integrins. After stimulation, the cells and culture supernatants were examined for ALP activity, type I collagen production, and integrin expression. The ALP activity was measured using a colorimetric assay with p-nitrophenyl phosphate and ALP staining. Enzyme-linked immunosorbent assay (ELISA) was used to determine type I collagen production, and ELISA and flow cytometric analysis were employed for assessment of integrin expression.

RESULTS

Both ALP activity and type I collagen production were upregulated when PDL cells were cultured in the presence of ascorbic acid (200 microM). Inhibitor of the formation of collagen triple helices and blocking antibodies to alpha2beta1 integrin inhibited ALP activity by 50% in ascorbic acid-stimulated PDL cells. Furthermore, ascorbic acid increased the cell surface expression of alpha2beta1 integrin.

CONCLUSIONS

Our findings indicated that ascorbic acid increases the ALP activity of PDL cells via type I collagen production and also enhances the expression of alpha2beta1 integrin, which is a major receptor of type I collagen. These results suggest that ascorbic acid promotes the osteoblastic differentiation of PDL cells by modulating type I collagen-alpha2beta1 integrin interaction.

MyoD enhances BMP7-induced osteogenic differentiation of myogenic cell cultures

The muscle-specific, basic helix-loop-helix transcription factor MyoD can induce cells from other mesenchymal lineages to express a skeletal muscle phenotype. Interestingly, MyoD is initially upregulated in myogenic cells incubated with bone morphogenetic proteins (BMPs), a treatment that induces osteogenic differentiation, suggesting that MyoD has a role in BMP-induced osteogenesis of myogenic cells. This possibility is supported by our observations that muscle satellite cells derived from adult MyoD(-/-) mice show severely impaired osteogenic induction by BMP-7 (osteogenic protein 1; OP-1) as indicated by the decreased gene expression of the bone markers alkaline phosphatase, osteocalcin, Runx2/Cbfa1, and Osterix. Ectopic expression of MyoD increased alkaline phosphatase activity and Osterix mRNA expression in response to BMP treatment. Similarly, ectopic expression of MyoD in the pluripotent mesenchymal cell line C3H10T1/2 increased alkaline phosphatase activity induced by BMP-7. Transcription assays showed that transfection with a MyoD-expression vector, but not other myogenic basic helix-loop-helix transcription factors (Myf5, myogenin) increased Runx2/Cbfa1 transactivation of a reporter gene construct containing either six OSE sequences in tandem or a single OSE site. This effect was enhanced by BMP treatment. These studies, therefore, demonstrate that the muscle transcription factor MyoD is required for efficient BMP-induced osteogenesis of myogenic cells and indicate that MyoD might exert its effects through co-operative interactions with Runx2/Cbfa1.

Young's interference of electrons in field emission patterns

We have observed interference fringes of electrons in field emission patterns from multiwalled carbon nanotubes at 60 K. The observed fringe pattern is reproduced by calculations based on the formula of Young's interference of two beams. Three-beam interference has also been detected over short time periods. We discuss the reason why Young's interference appears in the electron emission pattern in accelerating fields.

Muscle satellite cells are multipotential stem cells that exhibit myogenic, osteogenic, and adipogenic differentiation

Muscle satellite cells are believed to represent a committed stem cell population that is responsible for the postnatal growth and regeneration of skeletal muscle. However, the observation that cultured myoblasts differentiate into osteocytes or adipocytes following treatment with bone morphogenetic proteins (BMPs) or adipogenic inducers, respectively, suggests some degree of plasticity within the mesenchymal lineage. To further investigate this phenomenon, we explore the osteogenic and adipogenic potential of satellite cells isolated from adult mice. Our experiments clearly demonstrate that satellite cell-derived primary myoblasts, expressing myogenic markers such as MyoD, Myf5, Pax7 and desmin, differentiated only into osteocytes or adipocytes following treatment with BMPs or adipogenic inducers, respectively However, satellite cells on isolated muscle fibers cultured in Matrigel readily differentiated into myocytes as well as osteogenic and adipogenic lineages, whereas primary myoblasts did not. Satellite cell-derived primary myoblasts isolated from mice lacking the myogenic transcription factor MyoD (MyoD-/-) differentiate into myocytes poorly in vivo and in vitro (Megeney et al., Genes Dev. 1996; Sabourin et. al, J. Cell Biol., 1999). Therefore, we tested whether MyoD-/- primary myoblasts display increased plasticity relative to wild type cells. Unexpectedly, the osteogenic or adipogenic differentiation potential of MyoD-/- primary myoblasts did not increase compared to wild-type cells. Taken together, these results strongly suggest that muscle satellite cells possess multipotential mesenchymal stem cell activity and are capable of forming osteocytes and adipocytes as well as myocytes.

Role of MAP kinases p42erk-2/p44erk-1 in cementum-derived attachment-protein-mediated cell attachment

Cementum-derived attachment protein (CAP) is a collagenous protein which promotes the attachment and spreading of periodontal cell types. We examined the role of the MEK/MAPK pathway in CAP-mediated fibroblast attachment. Human gingival fibroblasts were labeled with 35S-methionine, and the effect of MAP kinase pathway inhibitor PD98059 on attachment and spreading on CAP-coated dishes was examined. Effect on cell proliferation on CAP-coated plates was determined by [3H]-thymidine uptake. Attachment of human gingival fibroblasts to CAP-containing surfaces activated extracellular-signal-regulated kinases (ERK) ERK-2 and ERK-1. In the absence of serum, the ERKs were activated 15 min after attachment, reaching peak levels after 3 hours, and the activity was sustained for at least 12 hours. The enzyme levels were inhibited in cells treated with PD98059. The PD98059 did not significantly affect the kinetics of fibroblast attachment or the number of cells attaching to CAP-coated plates. However, cell spreading was retarded. DNA synthesis as indicated by [3H]-thymidine uptake was not significantly affected. In contrast to PD98059, attachment, spreading, and [3H]-thymidine uptake were inhibited by the protein tyrosine kinase inhibitor genestein. Our results indicate that the MEK/MAPK pathway participates in CAP-mediated fibroblast spreading, but cell attachment and proliferation do not appear to require ERK-2.

Periodontal-derived cells attach to cementum attachment protein via alpha 5 beta 1 integrin

A specific collagenous cementum attachment protein (CAP) has been identified in human cementum which promotes selective cell migration towards and attachment of various periodontal derived cell populations to root surfaces in vitro. The CAP is known to support attachment of periodontal-derived cell via an RGD motif, which suggests an integrin-mediated mode of attachment. The purpose of the present study was to ascertain which integrin(s) are involved in the attachment of periodontal-derived cells to CAP. The integrins examined comprised subunits of the major receptors for fibronectin (alpha 5) and collagen (alpha 2, alpha 3), as well as the common beta 1 subunit which is present in many extracellular matrix receptors. The wells of 48-well non-tissue culture treated plates were coated with CAP (2 micrograms/ml). For negative and positive controls the wells were coated with bovine serum albumin and fibronectin (5 micrograms/ml), respectively. Human gingival fibroblasts and periodontal ligament fibroblasts were labeled with [3H]-proline, incubated with anti-integrin antibodies and added to the precoated wells. Attachment was assessed after incubating the cells for 1 h at 37 degrees C in the presence of the antibodies. Antibodies to alpha 5 and beta 1 inhibited the attachment of both human gingival fibroblasts and human periodontal ligament fibroblasts to CAP, while anti alpha 2 and alpha 3 antibodies did not affect the attachment. The binding of the fibroblasts to fibronectin was also inhibited by anti-alpha 5 and beta 1 antibodies, both of which are components of the "classical" fibronectin receptor and remained unaffected by the addition of anti-alpha 2 and alpha 3 antibodies. Proteins migrating in SDS-polyacrylamide gels in positions similar to the alpha 5 and beta 1 integrin subunits were present in fractions bound to a column of CAP coupled to Sepharose CL-4B. These results indicate that the attachment to CAP of the periodontal-derived cells, human gingival fibroblasts and human periodontal ligament fibroblasts, is mediated primarily via the integrin alpha 5 beta 1.

Bone morphogenetic protein-2 inhibits terminal differentiation of myogenic cells by suppressing the transcriptional activity of MyoD and myogenin

Bone morphogenetic protein (BMP) is a family of cytokines that induce ectopic bone formation when implanted into muscular tissues. We reported that BMP-2 inhibits the terminal differentiation of C2C12 myoblasts and converts them into osteoblast lineage cells (Katagiri, T., Yamaguchi, A., Komaki, M., Abe, E., Takahashi, N., Ikeda, T., Rosen, V., Wozney, J. M., Fujisawa-Sehara, A., and Suda, T. (1994) J. Cell Biol. 127, 1755-1766). In the present study, we examined the molecular mechanism of the inhibitory effect of BMP-2 on terminal differentiation of myogenic cells. When either MyoD or myogenin cDNA was introduced into C3H10T1/2 (10T1/2) cells with a muscle-specific CAT reporter containing four copies of the right E-box of muscle creatine kinase (MCK) enhancer, the CAT activity was dose-dependently suppressed by BMP-2. Furthermore, BMP-2 inhibited the terminal differentiation of these subclonal 10T1/2 cells that stably expressed MyoD or myogenin into mature myotubes that expressed myosin heavy chain and troponin T. The differentiation of a subclone of the MyoD-transfected NIH3T3 cells into mature muscle cells was also inhibited by BMP-2. BMP-2 induced alkaline phosphatase activity in 10T1/2-derived, but not in NIH3T3-derived MyoD-transfected cells. These cells constitutively expressed exogenous MyoD and myogenin, which were localized exclusively in the nuclei irrespective of the presence and the absence of BMP-2. However, these cells failed to express the mRNAs of endogenous myogenic factors and MCK when cultured with BMP-2. In the electrophoresis mobility shift assay using nuclear extracts of the myogenic cells, MyoD and myogenin bound to the right E-box in the enhancer region of the MCK gene even in the presence of BMP-2. These results suggest that BMP-2 inhibits the terminal differentiation of myogenic cells by suppressing the transcriptional activity of the myogenic factors.