Experimental Model of Ligature-Induced Peri-Implantitis in Mice.

Dental implants have a high success and survival rate. However, complications such as peri-implantitis (PI) are highly challenging to treat. PI is characterized by inflammation in the tissues around dental implants with progressive loss of supporting bone. To optimize dental implants' longevity in terms of health and functionality, it is crucial to understand the peri-implantitis pathophysiology. In this regard, using mouse models in research has proven clear benefits in recreating clinical circumstances. This study aimed to describe an experimental model of ligature-induced peri-implantitis in mice and determine whether there is effectiveness in inducing this disease, given the observed bone and tissue changes. The experimental peri-implantitis induction comprehends the following steps: teeth extraction, implant placement, and ligature-inducted PI. A sample of eighteen 3-week-old C57BL/6J male mice was divided into two groups, ligature (N=9) and control non-ligature (N=9). The evaluation of clinical, radiographical, and histological factors was performed. The ligature group showed significantly higher bone loss, increased soft tissue edema, and apical epithelial migration than the non-ligature group. It was concluded that this pre-clinical model can successfully induce peri-implantitis in mice.

"Evaluation of 4 and 8 weeks of healing in a murine implant model".

Dental implants are increasing in prevalence as desirable options for replacing missing teeth. Unfortunately, implants come with complications, and animal models are crucial to studying the pathophysiology of complications. Current murine model experiments can be lengthy, with eight weeks of extraction socket healing before implant placement. Therefore, we aimed to investigate the efficacy of decreasing extraction healing time from eight to four weeks in a dental implant mouse model. Thirty-one three-week-old C57BL/6J male mice underwent maxillary first and second molar extractions followed by eight (control) or four (test) weeks of extraction socket healing before implant placement. Mice were euthanized after four weeks of implant osseointegration. Samples were analyzed via microcomputed tomography and histology. When mice received implants four weeks following extractions, there was no statistical difference in initial bone crest remodeling or surrounding bone volume compared to those after eight weeks of healing. Histologically, the hard and soft tissues surrounding both groups of implants displayed similar alveolar bone levels, inflammatory infiltrate, osteoclast count, and collagen organization. A four-week extraction healing period can be utilized without concern for osseointegration in a murine implant model and is a viable experimental alternative to the previous eight weeks of healing. While small animal implant models are less directly applicable to humans, advancements in experimental methods will ultimately benefit patients receiving dental implants through improved prevention and treatment of complications. Subsequent research could investigate occlusal effects or whether healing time affects prognosis following induction of peri-implantitis.

The potential impact of periodontitis on cerebral small vessel disease.

Cerebral small vessel disease (CSVD) is a term used to describe abnormalities in the intracranial microvasculature affecting small arteries, arterioles, capillaries, and venules. The etiology of these conditions is not fully understood but inflammation appears to play a significant role. Periodontal diseases have been associated with conditions such as stroke and dementia, which are clinical consequences of CSVD. Periodontitis is a highly prevalent chronic multifactorial inflammatory disease regulated by the host immune response against pathogenic bacterial colonization around the teeth. The inflammatory response and the microbial dysbiosis produce pro-inflammatory cytokines that can reach the brain and promote local changes. This review will explore the potential association between periodontitis and CSVD by assessing the impact of periodontitis-induced inflammation and periodontopathogenic bacteria on the underlying mechanisms leading to CSVD. Given the association of periodontitis with stroke and dementia, which are clinical features of CSVD, it may be possible to suggest a link with CSVD. Current evidence linking periodontitis with neuroimaging findings of CSVD enforces the possible link between these conditions.

Association between sequelae of COVID-19 with periodontal disease and obesity: A cross-sectional study.

BACKGROUND: To assess the sequelae of coronavirus disease 2019 (COVID-19) and associated factors, such as obesity and periodontitis in adults. METHODS: The study included 128 individuals aged ≥35 years with a history of a diagnosis of COVID-19 through real-time polymerase chain reaction (RT-PCR), from Pelotas, Brazil. Self-report sequelae from COVID-19 were defined as the primary outcome. A questionnaire containing sociodemographic, medical, behavioral and self-report of sequelae of COVID-19 was applied. A complete periodontal clinical examination was performed. Weight and height were assessed. Uni-, bi- and multivariate analyses were performed using Poisson regression with robust variance. Additional analyses were performed considering obesity as a subgroup. RESULTS: When considering the whole sample, no statistically significant associations between sequelae of COVID-19 with periodontitis (prevalence ratio [PR]:1.14;95% confidence interval [95%CI]: 0.80-1.61) and obesity (0.93 [0.68-1.26]) were identified. In the subgroup analysis, considering only individuals with obesity, those diagnosed with generalized periodontitis had 86% higher probability to have sequelae of COVID-19 when compared to individuals with periodontal health or localized periodontitis. However, when only those without obesity were considered, no significant association with periodontal status was detected (0.82 [0.55-1.23). No significant association with periodontal status were observed when the severity of sequelae (no sequelae, 1 sequela, and >1 sequela) were considered (p > 0.05). CONCLUSIONS: Individuals diagnosed with obesity and periodontitis have a higher PR of reporting sequelae from COVID-19 compared to individuals with only obesity.

Association between different dietary patterns and eating disorders and periodontal diseases.

Periodontal diseases is a highly prevalent chronic condition regulated by the host immune response to pathogenic bacterial colonization on the teeth surfaces. Nutrition is a critical component in the modulation of the immune system, hence the importance of a balanced diet. With the understanding of how dietary intake composition affects various health outcomes, nutrient diversity has been reported as a modifiable risk factor for periodontal disease. Eating disorders and different dietary patterns can be associated with periodontal diseases. In this sense, balanced and healthy nutrition plays a major role in maintaining the symbiosis between oral microbiota and periodontal health. Therefore, this review seeks to report the associations found in the literature between high- or low-fat/sodium/sugar, eating disorders and periodontal diseases. It was found that some dietary patterns such as high carbohydrate/sugar, high fat, and low fiber intake may be associated with periodontal disease. In addition, the presence of eating disorders can negatively impact patients' oral health and it is related to the development of several complications, including periodontal diseases. In both situations, nutritional and vitamin deficiencies can aggravate the periodontal condition. However, the relationship between periodontal disease, dietary patterns, and eating disorders still needs more scientific support to be well established, mainly in the sense of pointing out a protective relationship between both.

Effect of mouthwashes on gingival healing after surgical procedures: A systematic review.

The aim of the present study was to perform a systematic review of the literature regarding the effect of different mouthwashes on gingival healing after oral surgery in adults. Searches were conducted in seven databases (PubMed/MEDLINE, Cochrane Library, Clinical Trials Registry, Embase, LILACS, Web of Science, and Google Scholar) for relevant randomized controlled trials (RCTs) published up to April 2022. The selection of studies, data extraction, and risk of bias appraisal were performed independently by two reviewers, and a third researcher was consulted to resolve disagreements. Data syntheses were presented narratively for the different criteria of gingival wound healing. Among 4502 articles retrieved from the databases, 13 studies met the eligibility criteria and were included in the present review. Chlorhexidine was the most frequent mouthwash studied (eight studies) and was used in different concentrations and combinations. Cetylpyridinium chloride, H2 Ocean Sea Salt, Commiphora molmol 0.5%, chlorhexidine 0.12%, and essential oils reported better healing than a negative control. However, the uncertain risk of bias in most RCTs included in this review precludes definitive conclusions. Well-designed RCTs are therefore still needed in this area.

Probiotic Lactobacillus rhamnosus EM1107 prevents hyperglycemia, alveolar bone loss, and inflammation in a rat model of diabetes and periodontitis.

BACKGROUND: This study evaluated the antihyperglycemic, anti-bone-resorptive, and anti-inflammatory efficacy of the probiotic Lactobacillus rhamnosus EM1107 in an experimental model of ligature-induced periodontitis in diabetic rats treated with metformin (Met). METHODS: A total of 114 male Wistar rats was randomly divided into six groups: (1) control, (2) experimental periodontitis (EP), (3) EP + diabetes mellitus (DM), (4) EP + probiotic (Prob), (5) EP + DM + Prob, and (6) EP + DM + Prob + Met. The animals received probiotic gavage during the 30 days of the experiment. DM was induced on the 14th day of the experiment with a single injection of streptozotocin into the penile vein, followed by ligature for EP induction and Met gavage on the 19th day and euthanasia on the 30th day. Heart blood, gingival and periodontal tissue, and hemimaxillae were collected. Biomolecular analysis, immunoenzymatic assays, histomorphology, and microtomographic analysis were performed. Data were statistically analyzed (p < 0.05). RESULTS: There was a significant reduction in interleukin-1ß (IL-1ß) and tumor necrosis factor-α (TNF-α) in the Prob groups (p < 0.05) as well as in blood glucose levels in the Prob and Met groups (p < 0.001). In addition, histomorphological analysis revealed that the Prob groups had a reduction in inflammatory infiltrate. Tartrate-resistant acid phosphatase (TRAP) and microtomographic analyses showed that the EP/DM/Prob/Met group had significantly lower linear and volumetric bone loss than those who had no treatment (p < 0.01). SOD and GPx immunostaining decreased in all groups receiving probiotics. CONCLUSION: The findings suggest the immunoinflammatory efficacy of the probiotic L. rhamnosus EM1107 administered either alone or in association with Met in type 1 DM associated with periodontitis.

Local delivery of a CXCR3 antagonist decreases the progression of bone resorption induced by LPS injection in a murine model.

OBJECTIVES: This experimental study was carried out to investigate the effects of locally delivered nanoparticles (AMG-487 NP) containing a CXCR3 antagonist in inhibiting the progression of LPS-induced inflammation, osteoclastic activity, and bone resorption on a murine model. MATERIALS AND METHODS: Thirty, 7-week-old C57BL/6 J male mice were used. Inflammatory bone loss was induced by Porphyromonas gingivalis-lipopolysaccharide (P.g.-LPS) injections between the first and second maxillary molars, bilaterally, twice a week for 6 weeks (n = 20). AMG-487 NP were incorporated into a liposome carrier and locally delivered on sites where P.g.-LPS was injected. Control mice (n = 10) were injected with vehicle only. Experimental groups included (1) control, (2) LPS, and (3) LPS + NP. At the end of 1 and 6 weeks, mice were euthanized, maxillae harvested, fixed, and stored for further analysis. RESULTS: Volumetric bone loss analysis revealed, at 1 week, an increase in bone loss in the LPS group (47.9%) compared to control (27.4%) and LPS + NP (27.8%) groups. H&E staining demonstrated reduced inflammatory infiltrate in the LPS + NP group compared to LPS group. At 6 weeks, volumetric bone loss increased in all groups; however, treatment with the CXCR3 antagonist (LPS + NP) significantly reduced bone loss compared to the LPS group. CXCR3 antagonist treatment significantly reduced osteoclast numbers when compared to LPS group at 1 and 6 weeks. CONCLUSIONS: This study showed that local delivery of a CXCR antagonist, via nanoparticles, in a bone resorption model, induced by LPS injection, was effective in reducing inflammation, osteoclast numbers, and bone loss. CLINICAL RELEVANCE: CXCR3 blockade can be regarded as a novel target for therapeutic intervention of bone loss. It can be a safe and convenient method for periodontitis treatment or prevention applicable in clinical practice.

The Microbiome in Periodontitis and Diabetes.

Objectives: To perform a comprehensive and integrative review of the available literature on the potential changes in the microbiome of healthy and individuals with diabetes under periodontal health and disease. Materials and Methods: The review was conducted by two independent reviewers. Indexed electronic databases (PubMed/Medline, Cochrane Library, Web of Science and Scopus) were searched, including articles published in English and dated from 5 years ago until December 2021. A manual search also was performed to identify co-related articles. Following the removal of duplicates and eligibility criteria, the articles were included in tables for analysis and described in the manuscript. Results: According to this review, diabetes mellitus was associated with significant changes in the subgingival and salivary microbiome, either in its association with periodontitis or in cases of periodontal health. In addition to affecting microbial diversity in terms of taxonomy, metagenomic studies have shown that this endocrine disorder may also be directly related to increased pathogenicity in the oral microbiome. Conclusion: Although the reviewed studies demonstrate important differences in the subgingival and salivary microbiome composition because of diabetes mellitus, further studies are needed to clarify the real effects of hyperglycemia on oral microbial profiles and support new diagnostic approaches and innovative treatments.

The Receptor AT1 Appears to Be Important for the Maintenance of Bone Mass and AT2 Receptor Function in Periodontal Bone Loss Appears to Be Regulated by AT1 Receptor.

A large number of experimental studies has demonstrated that angiotensin II (Ang II) is involved in key events of the inflammatory process. This study aimed to evaluate the role of Ang II type 1 (AT1) and Ang II type 2 (AT2) receptors on periodontitis. Methods: Experimental periodontitis was induced by placing a 5.0 nylon thread ligature around the second upper left molar of AT1 mice, no-ligature or ligature (AT1-NL and AT1-L), AT2 (AT2-NL or AT2-L) and wild type (WT-NL or L). Alveolar bone loss was scanned using Micro-CT. Cytokines, peptides and enzymes were analyzed from gingival tissues by Elisa and RT-PCR. Results: The blockade of AT1 receptor resulted in bone loss, even in healthy animals. Ang II receptor blockades did not prevent linear bone loss. Ang II and Ang 1-7 levels were significantly increased in the AT2-L (p < 0.01) group compared to AT2-NL and AT1-L. The genic expression of the Mas receptor was significantly increased in WT-L and AT2-L compared to (WT-NL and AT2-NL, respectively) and in AT1-L. Conclusions: Our data suggest that the receptor AT1 appears to be important for the maintenance of bone mass. AT2 receptor molecular function in periodontitis appears to be regulated by AT1.

Association between metabolic syndrome and periodontitis: The role of lipids, inflammatory cytokines, altered host response, and the microbiome.

Periodontitis has been associated with many systemic diseases and conditions, including metabolic syndrome. Metabolic syndrome is a cluster of conditions that occur concomitantly and together they increase the risk of cardiovascular disease and double the risk of type 2 diabetes. In this review, we focus on the association between metabolic syndrome and periodontitis; however, we also include information on diabetes mellitus and cardiovascular disease, since these two conditions are significantly intertwined with metabolic syndrome. With regard to periodontitis and metabolic syndrome, to date, the vast majority of studies point to an association between these two conditions and also demonstrate that periodontitis can contribute to the development of, or can worsen, metabolic syndrome. Evaluating the effect of metabolic syndrome on the salivary microbiome, data presented herein support the hypothesis that the salivary bacterial profile is altered in metabolic syndrome patients compared with healthy patients. Considering periodontitis and these three conditions, the vast majority of human and animal studies point to an association between periodontitis and metabolic syndrome, diabetes, and cardiovascular disease. Moreover, there is evidence to suggest that metabolic syndrome and diabetes can alter the oral microbiome. However, more studies are needed to fully understand the influence these conditions have on each other.

AT1 and AT2 Receptor Knockout Changed Osteonectin and Bone Density in Mice in Periodontal Inflammation Experimental Model.

BACKGROUND: The aim of this study was to evaluate the role of AT1 and AT2 receptors in a periodontal inflammation experimental model. METHODS: Periodontal inflammation was induced by LPS/Porphyromonas gingivalis. Maxillae, femur, and vertebra were scanned using Micro-CT. Maxillae were analyzed histopathologically, immunohistochemically, and by RT-PCR. RESULTS: The vertebra showed decreased BMD in AT1 H compared with WT H (p < 0.05). The femur showed increased Tb.Sp for AT1 H and AT2 H, p < 0.01 and p < 0.05, respectively. The Tb.N was decreased in the vertebra (WT H-AT1 H: p < 0.05; WT H-AT2 H: p < 0.05) and in the femur (WT H-AT1 H: p < 0.01; WT H-AT2 H: p < 0.05). AT1 PD increased linear bone loss (p < 0.05) and decreased osteoblast cells (p < 0.05). RANKL immunostaining was intense for AT1 PD and WT PD (p < 0.001). OPG was intense in the WT H, WT PD, and AT2 PD when compared to AT1 PD (p < 0.001). AT1 PD showed weak immunostaining for osteocalcin compared with WT H, WT PD, and AT2 PD (p < 0.001). AT1 H showed significantly stronger immunostaining for osteonectin in fibroblasts compared to AT2 H (p < 0.01). CONCLUSION: AT1 receptor knockout changed bone density, the quality and number of bone trabeculae, decreased the number of osteoblast cells, and increased osteonectin in fibroblasts.

Zirconia/hydroxyapatite (80/20) scaffold repair in critical size calvarial defect increased FGF-2, osteocalcin and OPG immunostaining and IL-10 levels.

The aim of this study was to characterize and evaluate zirconia/hydroxyapatite in a critical size calvarial defect model in rats. Zirconia/hydroxyapatite (80/20) scaffold was characterized by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). Critical size (8 mm) calvarial defects were created in wistar rats (n=48) and divided into four groups (90 days): G0 Group: positive control; G1 Group: hydroxyapatite; G2 Group: Zirconia; G3 Group: Zirconia/hydroxyapatite (80/20). Calvaria were subjected to Micro CT, histological and immunohistochemical analyses (RANK, RANKL, OPG, osteocalcin and FGF-2). IL-1 beta, IL-10 and TNF-alpha levels were analyzed by Elisa Immunoassay. The XRD analysis confirmed the formation of a crystalline structure and SEM showed the presence of regions corresponding to Zirconia and Hydroxyapatite. The Micro CT showed increased bone volume (BV/TV) and bone mineral density (BMD) in the G3 group (P<0.05). In addition, discrete periosteal bone formation was found at the interface of the defect edge and the external surface of the scaffold in the G3 group, showing osteocytes inside and osteoblasts (P<0.05) with scarce mononuclear inflammatory cells (P<0.01) in the central region of the defect. The immunostaining was moderate for RANKL, Osteocalcin and FGF-2 in the G3 group (P<0.5), while it was intense for OPG (P<0.001). IL-1 beta levels were decreased and IL-10 levels increased (P<0.05). Zirconia/hydroxyapatite (80/20) scaffold repair in critical size calvarial defects increased bone density, osteoblast and osteoclast cell numbers, FGF-2, osteocalcin and OPG immunostaining and IL-10 levels.

The Modified Apically Repositioned Flap Technique and Its Potential to Create Attached Gingiva in Areas with No Keratinized Tissue: A Long-Term (1 to 11 Years) Retrospective Case Series Study.

The modified apically repositioned flap (MARF) technique has been previously published as a successful method to increase the zone of attached gingiva with numerous advantages, such as simplicity, predictability, and long-term stability. However, this technique has only been used in areas with at least 0.5 mm of attached gingiva, presurgically. In the current study, the MARF technique was utilized in 21 sites (teeth) with no attached gingiva and only mucosa comprising the marginal tissue. The long-term follow-up results over the course of 1 to 11 years (average follow-up: 3.2 years) show a statistically significant increase of 3.6 ± 0.8 mm for keratinized tissue and of 2.21 ± 0.83 mm for attached gingiva, and no increases in probing depths or marginal tissue recession. These results indicate that the MARF procedure has generated keratinized tissue and attached gingiva in areas with a presurgical absence of these tissues.

Rieger Syndrome: Rehabilitation With Dental Implants.

INTRODUCTION: Axenfeld-Rieger syndrome (ARS), also known as Rieger syndrome, is a rare autosomal dominant condition defined by craniofacial, ocular, dental, periumbilical, and systemic anomalies. CASE PRESENTATION: This case report describes in detail a multidisciplinary approach to successfully restore the oral function and esthetics of a 22-year-old patient diagnosed with ARS. The patient's clinical evaluation revealed that the area corresponding with teeth #13, #12, #11, #21, #22, and #23 was occupied by four malformed and/or deciduous teeth. The four anterior teeth were extracted, and socket preservation was performed using bovine-derived porous bone mineral. Six months after extractions, two implants were placed in the location of the lateral incisors and additional bone graft was performed. Two months after the initial healing, a temporary fixed partial was delivered and 9 months after implant placement the implants were restored with a porcelain-fused-to-metal fixed partial denture. CONCLUSIONS: The use of implant-supported fixed partial dentures to restore missing teeth in patients with ARS provides biological and mechanical advantages over conventional, fixed, or removable prosthodontics. Further evaluation is needed to determine the longevity and long-term prognosis of dental implants in patients with ARS.

Vasculature submucosal changes at early stages of osteonecrosis of the jaw (ONJ).

Osteonecrosis of the jaw (ONJ), a rare, but potentially severe side effect of anti-resorptive medications, presents as exposed bone in the maxillofacial region lasting for at least 8 weeks. While clinical experience and animal models concur in finding that systemic antiresorptive treatment in conjunction with local risk factors, such as tooth extraction or dental disease may lead to ONJ development, the subclinical molecular changes that precede bone exposure remain poorly understood. The identification of these changes is not only important in understanding disease pathophysiology, but could provide potential for treatment development. Here, we evaluated the early stages of ONJ utilizing a model of experimental periodontitis (EP) in mice treated with two different types of antiresorptives, targeting potential changes in vasculature, hypoxia, oxidative stress, and apoptosis. Antiresorptive treatment in animals with EP increased levels of empty osteocytic lacunae and increased ONJ prevalence compared to Veh animals. The arteriole and venule network seen around EP areas was diminished in animals treated with antiresorptives. Higher levels of vascular endothelial growth factor A (VEGF-A) and vascular cell adhesion protein-1 (VCAM-1) were observed 1-week following EP in treated animals. Finally, levels of hypoxia, oxidative stress, and apoptosis remained high in antiresorptive treated animals with EP through the duration of the experiment. Together, our data point to subclinical vasculature organizational disturbances that subsequently affect levels of hypoxia, oxidative stress, and apoptosis in the area of developing ONJ.

Gliclazide reduced oxidative stress, inflammation, and bone loss in an experimental periodontal disease model.

OBJECTIVE: The aim of this study was to evaluate the effects of gliclazide on oxidative stress, inflammation, and bone loss in an experimental periodontal disease model. MATERIAL AND METHODS: Male albino Wistar rats were divided into no ligature, ligature, and ligature with 1, 5, and 10 mg/kg gliclazide groups. Maxillae were fixed and scanned using micro-computed tomography to quantify linear and bone volume/tissue volume (BV/TV) and volumetric bone loss. Histopathological, immunohistochemical and immunofluorescence analyses were conducted to examine matrix metalloproteinase-2 (MMP-2), cyclooxygenase 2 (COX-2), cathepsin K, members of the receptor activator of the nuclear factor kappa-Β ligand (RANKL), receptor activator of nuclear factor kappa-Β (RANK), osteoprotegerin (OPG) pathway, macrophage migration inhibitory factor (MIF), superoxide dismutase-1 (SOD-1), glutathione peroxidase-1 (GPx-1), NFKB p 50 (Cytoplasm), NFKB p50 NLS (nuclear localization signal), PI3 kinase and AKT staining. Myeloperoxidase activity, malondialdehyde and glutathione levels, while interleukin-1 beta (IL-1ß) and tumor necrosis factor-alpha (TNF-α) levels were evaluated by spectroscopic ultraviolet-visible analysis. A quantitative reverse transcription polymerase chain reaction was used to quantify the gene expression of the nuclear factor kappa B p50 subunit (NF-κB p50), phosphoinositide 3-kinase (PI3k), protein kinase B (AKT), and F4/80. RESULTS: Micro-computed tomography showed that the 1 mg/kg gliclazide treatment reduced linear bone loss compared to the ligature, 5 mg/kg gliclazide, and 10 mg/kg gliclazide treatments. All concentrations of gliclazide increased bone volume/tissue volume (BV/TV) compared to the ligature group. Treatment with 1 mg/kg gliclazide reduced myeloperoxidase activity, malondialdehyde, IL-1ß, and TNF-α levels (p≤0.05), and resulted in weak staining for COX-2, cathepsin k, MMP-2, RANK, RANKL, SOD-1, GPx-1,MIF and PI3k. In addition, down-regulation of NF-κB p50, PI3k, AKT, and F4/80 were observed, and OPG staining was strong after the 1 mg/kg gliclazide treatment. CONCLUSIONS: This treatment decreased neutrophil and macrophage migration, decreased the inflammatory response, and decreased bone loss in rats with ligature-induced periodontitis.

Clinically Relevant Doses of Sclerostin Antibody Do Not Induce Osteonecrosis of the Jaw (ONJ) in Rats with Experimental Periodontitis.

Antiresorptive agents, such as bisphosphonates and denosumab, are frequently used for the management of osteoporosis. Indeed, both medications decrease the risk of osteoporotic fractures; however, these medications are associated with rare but potentially severe side effects, such as osteonecrosis of the jaw (ONJ). ONJ, defined as an area of exposed bone in the maxillofacial region that lasts for 8 weeks, often presents with significant pain and infection and can lead to serious complications. Interestingly, other treatments for osteoporosis have been developed, such as antibodies against the osteocyte-secreted protein, sclerostin. Sclerostin functions to inhibit the Wnt signaling cascade, leading to inhibition of bone formation. In clinical trials, a sclerostin antibody (romosozumab, Amgen Inc., UCB Brussels) increases bone formation and lowers the risk of osteoporotic fractures. However, in conjunction with increased osteoblastic activity, a reduction in bone resorption markers is observed. This antiresorptive effect raises the concern of possible ONJ development in patients treated with sclerostin antibodies. Here, utilizing ligature-induced experimental periodontitis (EP), we evaluated the effects of sclerostin inhibition on the development of ONJ-like lesions in ovariectomized rats. Beginning 8 weeks post-ovariectomy, rats were treated for 22 weeks with weekly injections of vehicle (Veh), 200 µg/kg zoledronic acid (ZA), a potent bisphosphonate at 100-fold the osteoporosis dose, or 5 mg/kg sclerostin antibody (Scl-Ab) at the osteoporotic dose. EP was initiated at week 12 and maintained for the remainder of the study. Scl-Ab treatment transiently increased serum P1NP, a bone formation marker, increased BV/TV, and decreased eroded surfaces in lumbar vertebrae. ZA-treated rats developed histologic features of ONJ, whereas Veh-treated controls did not. Scl-Ab animals lost less periodontal bone in sites with EP. However, these animals presented with no histologic signs of ONJ. In conclusion, sclerostin inhibition enhanced structural bone parameters, without inducing ONJ-like lesions, in ovariectomized rats with EP. © 2018 American Society for Bone and Mineral Research.

Gliclazide reduced oxidative stress, inflammation, and bone loss in an experimental periodontal disease model

Abstract Objective The aim of this study was to evaluate the effects of gliclazide on oxidative stress, inflammation, and bone loss in an experimental periodontal disease model. Material and Methods Male albino Wistar rats were divided into no ligature, ligature, and ligature with 1, 5, and 10 mg/kg gliclazide groups. Maxillae were fixed and scanned using micro-computed tomography to quantify linear and bone volume/tissue volume (BV/TV) and volumetric bone loss. Histopathological, immunohistochemical and immunofluorescence analyses were conducted to examine matrix metalloproteinase-2 (MMP-2), cyclooxygenase 2 (COX-2), cathepsin K, members of the receptor activator of the nuclear factor kappa-Β ligand (RANKL), receptor activator of nuclear factor kappa-Β (RANK), osteoprotegerin (OPG) pathway, macrophage migration inhibitory factor (MIF), superoxide dismutase-1 (SOD-1), glutathione peroxidase-1 (GPx-1), NFKB p 50 (Cytoplasm), NFKB p50 NLS (nuclear localization signal), PI3 kinase and AKT staining. Myeloperoxidase activity, malondialdehyde and glutathione levels, while interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) levels were evaluated by spectroscopic ultraviolet-visible analysis. A quantitative reverse transcription polymerase chain reaction was used to quantify the gene expression of the nuclear factor kappa B p50 subunit (NF-κB p50), phosphoinositide 3-kinase (PI3k), protein kinase B (AKT), and F4/80. Results Micro-computed tomography showed that the 1 mg/kg gliclazide treatment reduced linear bone loss compared to the ligature, 5 mg/kg gliclazide, and 10 mg/kg gliclazide treatments. All concentrations of gliclazide increased bone volume/tissue volume (BV/TV) compared to the ligature group. Treatment with 1 mg/kg gliclazide reduced myeloperoxidase activity, malondialdehyde, IL-1β, and TNF-α levels (p≤0.05), and resulted in weak staining for COX-2, cathepsin k, MMP-2, RANK, RANKL, SOD-1, GPx-1,MIF and PI3k. In addition, down-regulation of NF-κB p50, PI3k, AKT, and F4/80 were observed, and OPG staining was strong after the 1 mg/kg gliclazide treatment. Conclusions This treatment decreased neutrophil and macrophage migration, decreased the inflammatory response, and decreased bone loss in rats with ligature-induced periodontitis.

Metformin Hydrochloride-Loaded PLGA Nanoparticle in Periodontal Disease Experimental Model Using Diabetic Rats.

Evidence shows that metformin is an antidiabetic drug, which can exert favorable anti-inflammatory effects and decreased bone loss. The development of nanoparticles for metformin might be useful for increased therapeutic efficacy. The aim of this study was to evaluate the effect of metformin hydrochloride-loaded Poly (d,l-Lactide-co-glycolide) (PLGA)/(MET-loaded PLGA) on a ligature-induced periodontitis model in diabetic rats. MET-loaded PLGA were characterized by mean diameter, particle size, polydispensity index, and entrapment efficiency. Maxillae were scanned using Microcomputed Tomography (µCT) and histopathological and immunohistochemical analysis. IL-1ß and TNF-α levels were analyzed by ELISA immunoassay. Quantitative RT-PCR was used (AMPK, NF-κB p65, HMGB1, and TAK-1). The mean diameter of MET-loaded PLGA nanoparticles was in a range of 457.1 ± 48.9 nm (p < 0.05) with a polydispersity index of 0.285 (p < 0.05), Z potential of 8.16 ± 1.1 mV (p < 0.01), and entrapment efficiency (EE) of 66.7 ± 3.73. Treatment with MET-loaded PLGA 10 mg/kg showed low inflammatory cells, weak staining by RANKL, cathepsin K, OPG, and osteocalcin, and levels of IL-1ß and TNF-α (p < 0.05), increased AMPK expression gene (p < 0.05) and decreased NF-κB p65, HMGB1, and TAK-1 (p < 0.05). It is concluded that MET-loaded PLGA decreased inflammation and bone loss in periodontitis in diabetic rats.