Effects of oleanolic acid acetate on bone formation in an experimental periodontitis model in mice

Effects of Oleanolic Acid Derived from Wine Pomace on Periodontopathic Bacterial Growth in Healthy Individuals: A Randomized Placebo-Controlled Study

Periodontal disease is caused by oral pathogenic bacteria and is associated with systemic disease and frailty. Therefore, its prevention is crucial in extending healthy life expectancy. This study aimed to evaluate the effect of orally administered oleanolic acid, extracted from wine pomace, on periodontopathic bacterial growth in healthy individuals. In this randomized, placebo-controlled, double-blind, parallel-group comparison study, 84 healthy adults were assigned to a placebo (n = 29), low-dose (n = 29, 9 mg oleanolic acid), or high-dose (n = 26, 27 mg oleanolic acid) groups. The number of oral bacteria in their saliva, collected before and 5 h after administration, was determined using the polymerase chain reaction-invader technique. The proportion of periodontopathic bacteria among the total oral bacteria in the saliva was calculated. Oleanolic acid significantly decreased the proportion of Porphyromonas gingivalis among the total oral bacteria in a dose-dependent manner (p = 0.005 (low-dose) and p = 0.003 (high-dose) vs. placebo, Williams' test). Moreover, high-dose oleanolic acid decreased the proportion of Tannerella forsythia (p = 0.064 vs. placebo, Williams' test). Periodontopathic bacteria are closely associated with the development and progression of periodontal disease; thus, the continuous daily intake of oleanolic acid derived from pomace may be helpful in maintaining a healthy oral microbiome by controlling the proportion of periodontopathic bacteria.

Resveratrol facilitates bone formation in high-glucose conditions

Periodontitis is known to be affected by high-glucose conditions, which poses a challenge to periodontal tissue regeneration, particularly in bone formation. In this study, the potential effects of resveratrol (3,5,4'-trihydroxystilbene, RSV) in facilitating bone formation under high-glucose conditions after periodontitis has been investigated. We focused on the analysis of osteoblasts and periodontal ligament cells, which are essential for bone formation including cell proliferation and differentiation. And we aimed to investigate the impact of RSV on bone healing, employed diabetic mouse model induced by streptozotocin and confirmed through histological observation. High-glucose conditions adversely affected cell proliferation and ALP activity in both MC3T3-E1 and hPDLF in vitro, with more significant impact on MC3T3-E1 cells. RSV under high-glucose conditions had positive effects on both, showing early-stage effects for MC3T3-E1 cells and later-stage effects for hPDLF cells. RSV seemed to have a more pronounced rescuing role in MC3T3-E1 cells. Increased ALP activity was observed and the expression levels of significant genes, such as Col 1, TGF-β1, ALP, and OC, in osteogenic differentiation were exhibited stage-specific expression patterns. Upregulated Col 1 and TGF-β1 were detected in the early stage, and then ALP and OC expressions became more pronounced in the later stages. Similarly, stronger positive reactions against RUNX2 were detected in the RSV-treated group compared to the control. Furthermore, in in vivo experiment, RSV stimulates the growth and differentiation of osteoblasts, thereby promoting bone formation. High-glucose levels have the potential to impair cellular functions and the regenerative capacity to facilitate bone formation with MC3T3-E1 rather than hPDLF cells. Resveratrol appears to facilitate the inherent abilities of MC3T3-E1 cells compared with hPDLF cells, indicating its potential capacity to restore functionality during periodontal regeneration.

Functional modulation of lysophosphatidic acid type 2 G-protein coupled receptor facilitates alveolar bone formation

Lipid biosynthesis is recently studied its functions in a range of cellular physiology including differentiation and regeneration. However, it still remains to be elucidated in its precise function. To reveal this, we evaluated the roles of lysophosphatidic acid (LPA) signaling in alveolar bone formation using the LPA type 2 receptor (LPAR2) antagonist AMG-35 (Amgen Compound 35) using tooth loss without periodontal disease model which would be caused by trauma and usually requires a dental implant to restore masticatory function. In this study, in vitro cell culture experiments in osteoblasts and periodontal ligament fibroblasts revealed cell type-specific responses, with AMG-35 modulating osteogenic differentiation in osteoblasts in vitro. To confirm the in vivo results, we employed a mouse model of tooth loss without periodontal disease. Five to 10 days after tooth extraction, AMG-35 facilitated bone formation in the tooth root socket as measured by immunohistochemistry for differentiation markers KI67, Osteocalcin, Periostin, RUNX2, transforming growth factor beta 1 (TGF-β1) and SMAD2/3. The increased expression and the localization of these proteins suggest that AMG-35 elicits osteoblast differentiation through TGF-β1 and SMAD2/3 signaling. These results indicate that LPAR2/TGF-β1/SMAD2/3 represents a new signaling pathway in alveolar bone formation and that local application of AMG-35 in traumatic tooth loss can be used to facilitate bone regeneration and healing for further clinical treatment.

Effects of erythropoietin on osteoblast in the tooth extraction socket in mice periodontitis model

Periodontitis is an excessive inflammatory event in tooth-supporting tissues and can cause tooth loss. We used erythropoietin (EPO), which has been reported to play an important role in bone healing and modulation of angiogenesis, as a therapeutic agent in vivo and in vitro experimental models to analyze its effect on periodontitis. First, EPO was applied to in vitro MC3T3-E1 cells and human periodontal ligament fibroblast (hPDLF) cells to examine its function in altered cellular events and gene expression patterns. In vitro cultivation of MC3T3-E1 and hPDLF cells with 10 IU/ml EPO at 24 and 48 h showed an obvious increase in cell proliferation. Interestingly, EPO treatment altered the expression of osteogenesis-related molecules, including alkaline phosphatase (ALP), bone morphogenetic protein-2 (BMP-2), and osteocalcin (OC) in MC3T3-E1 cells but not in hPDLF cells. In particular, MC3T3-E1 cells showed increased expression of ALP, BMP-2, and OC on day 5, while hPDLF cells showed increased expression of BMP-2, and OC on day 14. Based on the in vitro examination, we evaluated the effect of EPO on bone formation using an experimentally-induced animal periodontitis model. After the induction of periodontitis in the maxillary left second M, 10 IU/ml of EPO was locally applied to the extraction tooth sockets. Histomorphological examination using Masson’s trichrome (MTC) staining showed facilitated bone formation in the EPO-treated groups after 14 days. Similarly, stronger positive reactions against vascular endothelial growth factor (VEGF), cluster of differentiation 31 (CD31), runt-related transcription factor 2 (RUNX2), and osteocalcin (OC) were detected in the EPO-treated group compared to the control. Meanwhile, myeloperoxidase, an inflammatory marker, was decreased in the EPO-treated group on days 1 and 5. Overall, EPO facilitates bone healing and regeneration through altered signaling regulation and modulation of inflammation in the osteoblast cell lineage and to a lesser extent in hPDLF cells.

Application of Ligature-Induced Periodontitis in Mice to Explore the Molecular Mechanism of Periodontal Disease

Periodontitis is an inflammatory disease characterized by the destruction of the periodontium. In the last decade, a new murine model of periodontitis has been widely used to simulate alveolar bone resorption and periodontal soft tissue destruction by ligation. Typically, 3-0 to 9-0 silks are selected for ligation around the molars in mice, and significant bone loss and inflammatory infiltration are observed within a week. The ligature-maintained period can vary according to specific aims. We reviewed the findings on the interaction of systemic diseases with periodontitis, periodontal tissue destruction, the immunological and bacteriological responses, and new treatments. In these studies, the activation of osteoclasts, upregulation of pro-inflammatory factors, and excessive immune response have been considered as major factors in periodontal disruption. Multiple genes identified in periodontal tissues partly reflect the complexity of the pathogenesis of periodontitis. The effects of novel treatment methods on periodontitis have also been evaluated in a ligature-induced periodontitis model in mice. This model cannot completely represent all aspects of periodontitis in humans but is considered an effective method for the exploration of its mechanisms. Through this review, we aimed to provide evidence and enlightenment for future studies planning to use this model.

The effect of a toothpaste containing oleanolic acid in reducing plaque and gingivitis: a proof-of-concept randomized trial

OBJECTIVES

To assess the safety and efficacy of an oleanolic acid (OA)-containing toothpaste in reducing gingival inflammation and plaque in patients with gingivitis.

METHODS

This proof-of-concept parallel, double-blind, randomized controlled clinical trial included 99 patients. Following a 1-week washout, patients were randomized into three groups: OA group (fluoride toothpaste containing 0.1% OA and placebo mouthwash); negative control (fluoride toothpaste and placebo mouthwash); and CHX group (fluoride toothpaste and 0.12% chlorhexidine mouthwash). Patients were clinically assessed at inclusion, pre-washout visit, baseline and after 4 days, 1 week and 2 weeks of twice-daily use of the products. Patients received a diary for documentation of bleeding on brushing and provided unstimulated saliva samples.

RESULTS

After two weeks, all groups showed significant reductions in all clinical parameters. The CHX group exhibited significantly greater reductions in gingival index and interproximal gingival index scores at week 2, as compared to patients in the negative control (p = 0.04). In contrast, reductions in gingival index scores did not differ between CHX and OA groups and between OA and negative control groups at week 2. The CHX group had significantly greater reductions in plaque index scores at day-4, 1-week and 2-week evaluations, as compared to the negative control and OA groups. The frequency of adverse events was similar among the groups. None of the groups reduced salivary transferrin levels. Finally, the OA group had the lowest percentage of self-reported bleeding events.

CONCLUSION

OA toothpaste failed to provide antiplaque and antigingivitis effects superior to those of a fluoride toothpaste after 2 weeks of use.

Resveratrol enhances bone formation by modulating inflammation in the mouse periodontitis model

OBJECTIVE

To evaluate the effect of resveratrol on periodontal bone regeneration after local delivery and to determine its effect on inflammatory mediators.

BACKGROUND

Resveratrol is considered an anti-inflammatory polyphenolic stilbene involved in the modulation of inflammation.

MATERIALS AND METHODS

Periodontitis was induced in mouse molars using a 5-day ligature model followed by the left second molar extraction and 50 µM resveratrol treatment for 1 and 2 weeks. We then examined specimens treated for 1 week histologically and with immunostaining. Microfocus-computed tomography (micro-CT) was used to examine the bone volume formation.

RESULTS

After 1 week of treatment, proinflammatory cytokine levels (TNF-alpha and IL6), cells exhibiting neutrophil and macrophage marker (MPO), cell proliferation marker (Ki67), and preosteoblastic marker (RUNX2) reactivity decreased in the resveratrol-treated specimens compared to the control group. In contrast, we observed a higher number of CD31-, F4/80-, and osteocalcin- (OCN-) positive cells in the resveratrol-treated specimens. After 2 weeks, micro-CT confirmed an increased bone mass in the region of the extraction socket in the resveratrol-treated group.

CONCLUSION

After 1 week, the resveratrol-treated specimens revealed evidence of inflammation modulation compared to the control group. These data suggest that resveratrol not only affects inflammation control but also is useful for treating periodontitis-related tissue defects and bone regeneration.

Facilitation of Bone Healing Processes Based on the Developmental Function of Meox2 in Tooth Loss Lesion

In the present study, we examined the bone healing capacity of Meox2, a homeobox gene that plays essential roles in the differentiation of a range of developing tissues, and identified its putative function in palatogenesis. We applied the knocking down of Meox2 in human periodontal ligament fibroblasts to examine the osteogenic potential of Meox2. Additionally, we applied in vivo periodontitis induced experiment to reveal the possible application of Meox2 knockdown for 1 and 2 weeks in bone healing processes. We examined the detailed histomorphological changes using Masson’s trichrome staining and micro-computed tomography evaluation. Moreover, we observed the localization patterns of various signaling molecules, including α-SMA, CK14, IL-1β, and MPO to examine the altered bone healing processes. Furthermore, we investigated the process of bone formation using immunohistochemistry of Osteocalcin and Runx2. On the basis of the results, we suggest that the knocking down of Meox2 via the activation of osteoblast and modulation of inflammation would be a plausible answer for bone regeneration as a gene therapy. Additionally, we propose that the purpose-dependent selection and application of developmental regulation genes are important for the functional regeneration of specific tissues and organs, where the pathological condition of tooth loss lesion would be.

Prophylactic and therapeutic roles of oleanolic acid and its derivatives in several diseases

Oleanolic acid (OA) and its derivatives are widely found in diverse plants and are naturally effective pentacyclic triterpenoid compounds with broad prophylactic and therapeutic roles in various diseases such as ulcerative colitis, multiple sclerosis, metabolic disorders, diabetes, hepatitis and different cancers. This review assembles and presents the latest in vivo reports on the impacts of OA and OA derivatives from various plant sources and the biological mechanisms of OA activities. Thus, this review presents sufficient data proposing that OA and its derivatives are potential alternative and complementary therapies for the treatment and management of several diseases.