Obesity influences the proteome of periodontal ligament tissues following periodontitis induction in rats.

BACKGROUND AND OBJECTIVES: Many studies have been conducted to better understand the molecular mechanism involved with periodontitis progression. There has been growing interest in the potential impact of obesity on periodontitis onset and progression, but the mechanisms involved remain to be elucidated. The present study was designed to determine the impact of obesity on experimentally induced periodontitis in rats and identify novel pathways involved. METHODS: Sixteen Holtzman rats were distributed into two groups (n = 8): ligature-induced periodontitis (P) and obesity plus ligature-induced periodontitis (OP). Obesity was induced by a high-fat diet for 70 days, whereas periodontitis was induced for 20 days, with a cotton thread placed around the upper first molars bilaterally. Alveolar bone loss was measured by microtomographic analysis and histologically by histometry on the hemimaxillae. The protein composition of the periodontal ligament was evaluated by proteomic analysis. RESULTS: Data analysis (body weight, adipose tissue weight, and blood test) confirmed obesity induction, whereas bone loss was confirmed by micro-CT and histologic analyses. Proteome analysis from the periodontal ligament tissues (PDL) identified 819 proteins, 53 exclusive to the P group, 28 exclusive to the OP group, and 738 commonly expressed. Validation was performed by immunohistochemistry for selected proteins (spondin1, vinculin, and TRAP). CONCLUSION: Histologically, it was found that obesity did not significantly affect bone loss resulting from periodontitis. However, the present study's findings indicated that obesity affects the proteome of PDL submitted to experimental periodontitis, allowing for identifying potential targets for personalized approaches.

Periodontal treatment of patients with hereditary hemorrhagic telangiectasia.

Hereditary hemorrhagic telangiectasia (HHT) is a rare condition in which fragile vascular walls lead to increased risks of bleeding, cerebral abscesses, arteriovenous malformations, anemia, and thrombosis. To date, no protocol has been established for optimizing the clinical outcomes of periodontal treatment in patients with this condition. The aim of this case report is to describe a safe clinical approach to periodontal treatment in a patient with HHT. A 39-year-old woman had a history of multiple macules on the oral mucosa, and a diagnosis of HHT was made based on the Curaçao diagnostic criteria (epistaxis, telangiectases, visceral lesions, and family history). Evaluation of the patient's periodontal clinical parameters and radiographs led to a diagnosis of generalized periodontitis, stage IV, grade C. The patient underwent nonsurgical periodontal therapy consisting of supragingival and subgingival scaling and root planing under a careful and specific protocol that included antibiotic prophylaxis before each session. Two months after therapy, the periodontal reevaluation showed improvement in the clinical parameters at most sites. Sites with remaining periodontal pockets were re-treated according to the same protocol, including the antibiotic prophylaxis. The patient was enrolled in a periodontal maintenance program, and her HHT was routinely monitored by her physician. Periodontal treatment may promote secondary complications in patients with HHT if appropriate systemic care is not provided, and the periodontal treatment plan should be designed individually for each patient. Establishing the correct HHT diagnosis and coordinating care with the patient's physician are essential to safe, effective treatment.

Cystatin-like protein of sweet orange (CsinCPI-2) modulates pre-osteoblast differentiation via ß-Catenin involvement.

Phytocystatins are endogenous cysteine-protease inhibitors present in plants. They are involved in initial germination rates and in plant defense mechanisms against phytopathogens. Recently, a new phytocystatin derived from sweet orange, CsinCPI-2, has been shown to inhibit the enzymatic activity of human cathepsins, presenting anti-inflammatory potential and pro-osteogenic effect in human dental pulp cells. The osteogenic potential of the CsinCPI-2 protein represents a new insight into plants cysteine proteases inhibitors and this effect needs to be better addressed. The aim of this study was to investigate the performance of pre-osteoblasts in response to CsinCPI-2, mainly focusing on cell adhesion, proliferation and differentiation mechanisms. Together our data show that in the first hours of treatment, protein in CsinCPI-2 promotes an increase in the expression of adhesion markers, which decrease after 24 h, leading to the activation of Kinase-dependent cyclines (CDKs) modulating the transition from G1 to S phases cell cycle. In addition, we saw that the increase in ERK may be associated with activation of the differentiation profile, also observed with an increase in the B-Catenin pathway and an increase in the expression of Runx2 in the group that received the treatment with CsinCPI-2.

Effects of obesity on periodontal tissue remodeling during orthodontic movement.

INTRODUCTION: Orthodontic movement triggers a sequence of cellular and molecular events that may be affected by different systemic conditions. This study evaluated the effect of obesity on rat periodontal tissue remodeling induced by mechanical orthodontic force. METHODS: Thirty-two Holtzman rats were distributed into 4 groups: control, obesity induction (O), orthodontic movement (M), and obesity induction and orthodontic movement (OM). Obesity was induced by a high-fat diet for 90 days. After 15 days of orthodontic movement, the animals were killed. Obesity induction was confirmed by animal body weight, adipose tissue weight, and serologic analysis. Periodontal tissue remodeling was evaluated using microcomputed tomography and histologic analysis. The gene expression of adipokines and cytokines in gingival tissues was evaluated. RESULTS: An increase in body and adipose tissue weight was observed in the obesity induction groups. The O group presented an increase in lipids and blood glucose. The OM group showed a decrease in bone volume fraction and bone mineral density compared with all other groups and a tendency for more rapid tooth movement than the M group. The OM group showed a higher quantity of inflammatory cells and higher Mmp1 expression than the O group. The O and OM groups showed higher Nampt expression than the control group and lower Nampt expression than the M group. CONCLUSIONS: Obesity modulates periodontal tissue remodeling during orthodontic movement and results in more inflammation and bone loss than in nonobese animals.

Topical application of lectin Artin M improves wound healing in defects created in the palatal mucosa: an in vivo study in dogs.

Previous studies have shown that topical application of lectin Artin-M accelerates wound healing in the rat oral mucosa. The aim of this study was to evaluate, by means of histology and immunohistochemistry (IHC) the effects of Artin-M on wound healing in the palatal mucosa in dogs. Three full thickness wounds of 6 mm diameter were surgically created in the palatal mucosa of twenty dogs and randomly divided into three groups according to one of the treatment assigned: Group C-Control (coagulum); Group A-Artin-M gel; Group V-Vehicle (carboxymethylcellulose 3%). Each animal received all the three experimental treatments. Afterwards, four animals were killed at 2, 4, 7, 14 and 21 days post-surgery. Wounded areas were photographed and scored for macroscopic evaluation. Biopsies were harvested and used for descriptive histological analysis, proliferating cell nuclear antigen IHC and measurement of myeloperoxidase activity. The results demonstrated faster wound closure in group A in comparison to the other groups in all the periods evaluated. Histological analyses exhibited improved re-epithelialization and collagen fiber formation resulting in faster maturation of granulation tissue in group A compared to the other groups by day 14. Treatment with Artin-M gel significantly induced cell proliferation and increased volumetric density of fibroblasts at day 2 and 4 (p < 0.05). Neutrophil infiltration in group A was significantly higher than the other groups (p < 0.05) at the same time points. Collectively, our findings demonstrated that Artin-M may potentially favor wound healing on palatal mucosa lesions via recruitment of neutrophils and promotion of cell proliferation.

In vivo and in vitro anti-inflammatory and pro-osteogenic effects of citrus cystatin CsinCPI-2.

Cystatins are natural inhibitors of cysteine peptidases. Recently, cystatins derived from plants, named phytocystatins, have been extensively studied. Among them, CsinCPI-2 proteins from Citrus sinensis were identified and recombinantly produced by our group. Thus, this study described the recombinant expression, purification, and inhibitory activity of this new phytocystatin against human cathepsins K and B and assessed the anti-inflammatory effect of CsinCPI-2 in vitro in mouse and in vivo in rats. In addition, the pro-osteogenic effect of CsinCPI-2 was investigated in vitro. The inflammatory response of mouse macrophage cells stimulated with P. gingivalis was modulated by CsinCPI-2. The in vitro results showed an inhibitory effect (p < 0.05) on cathepsin K, cathepsin B, IL-1ß, and TNF-α gene expression. In addition, CsinCPI-2 significantly inhibited in vivo the activity of TNF-α (p < 0.05) in the blood of rats, previously stimulated by E. coli lipopolysaccharide (LPS). CsinCPI-2 had a pro-osteogenic effect in human dental pulp cells, demonstrated by the increase in alkaline phosphatase (ALP) activity, deposition of mineralized nodules, and the gene expression of the osteogenic markers as bone morphogenetic protein 2 (BMP-2), runt-related transcription factor 2 (Runx-2), ALP, osteocalcin, and bone sialoprotein (BSP). These preliminary studies suggested that CsinCPI-2 has a potential anti-inflammatory, and at the same time, a pro-osteogenic effect. This may lead to new therapies for the control of diseases where inflammation plays a key role, such as periodontal disease and apical periodontitis.

Systemic Resolvin E1 (RvE1) Treatment Does Not Ameliorate the Severity of Collagen-Induced Arthritis (CIA) in Mice: A Randomized, Prospective, and Controlled Proof of Concept Study.

Specialized proresolving mediators (SPRM), which arise from n-3 long-chain polyunsaturated fatty acids (n-3FA), promote resolution of inflammation and may help to prevent progression of an acute inflammatory response into chronic inflammation in patients with arthritis. Thus, this study is aimed at determining whether systemic RvE1 treatment reduces arthritis onset and severity in murine collagen-induced arthritis (CIA) and spontaneous cytokine production by human rheumatoid arthritis (RA) synovial explants. 10-week-old DBA1/J male mice were subjected to CIA and treated systemically with 0.1 µg RvE1, 1 µg RvE1, 5 mg/kg anti-TNF (positive control group), PBS (negative control group), or with a combination of 1 µg of RvE1 plus 5 mg/kg anti-TNF using prophylactic or therapeutic strategies. After CIA immunization, mice were treated twice a week by RvE1 or anti-TNF for 10 days. Arthritis development was assessed by visual scoring of paw swelling and histology of ankle joints. Moreover, human RA synovial explants were incubated with 1 nM, 10 nM, or 100 nM of RvE1, and cytokine levels (IL-1ß, IL-6, IL-8, IL-10, INF-γ, and TNF-α) were measured using Luminex bead array. CIA triggered significant inflammation in the synovial cavity, proteoglycan loss, and cartilage and bone destruction in the ankle joints of mice. Prophylactic and therapeutic RvE1 regimens did not ameliorate CIA incidence and severity. Anti-TNF treatment significantly abrogated signs of joint inflammation, bone erosion, and proteoglycan depletion, but additional RvE1 treatment did not further reduce the anti-TNF-mediated suppression of the disease. Treatment with different concentrations of RvE1 did not decrease the expression of proinflammatory cytokines in human RA synovial explants in the studied conditions. Collectively, our findings demonstrated that RvE1 treatment was not an effective approach to treat CIA in DBA1/J mice in both prophylactic and therapeutic strategies. Furthermore, no effects were noticed when human synovial explants were incubated with different concentrations of RvE1.

Evaluation of bone turnover after bisphosphonate withdrawal and its influence on implant osseointegration: an in vivo study in rats.

OBJECTIVES: The aim of this study was to investigate bone turnover alterations after alendronate (ALD) withdrawal and its influence on dental implants osseointegration. MATERIALS AND METHODS: Seventy female Wistar rats were randomly divided in 2 groups that received on day 0 either placebo (control group-CTL; n = 10) or 1 mg/kg sodium alendronate (ALD; n = 60) once a week for 4 months. At day 120, ALD treatment was suspended for 50 animals. Then, a titanium implant was placed in the left tibia of each rat that were randomly allocated in five subgroups of ten animals each, according to the period of evaluation: day 0 (INT-0), day 7 (INT-7), day 14 (INT-14), day 28 (INT-28), and day 45 (INT-45) after ALD withdrawal. CTL group and a group that received ALD until the end of the experimental period (non-interrupted group-non-INT; n = 10) underwent implant placement on day 120. Animals were euthanized 28 days after implant surgery. Bone mineral density (BMD) of femur and lumbar vertebrae were evaluated by DXA, biochemical markers of bone turnover were analyzed by ELISA, and bone histomorphometry was performed to measure bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO). RESULTS: All groups receiving ALD showed higher BMD values when compared to CTL group, which were maintained after its withdrawal. Decreased concentrations in all bone turnover markers were observed in the non-INT group, and in the groups in which ALD was discontinued compared to the CTL group. The non-INT group showed lower %BIC and notably changes in bone quality, which was persistent after drug withdrawal. CONCLUSION: Collectively, the findings of this study demonstrated that ALD therapy decreased bone turnover and impaired bone quality and quantity around dental implants, and that its discontinuation did not reverse these findings. CLINICAL RELEVANCE: The severe suppression of bone turnover caused by the prolonged use of ALD may alter the capacity of bone tissue to integrate with the implant threads impairing the osseointegration process.

Linkage of Periodontitis and Rheumatoid Arthritis: Current Evidence and Potential Biological Interactions.

The association between rheumatoid arthritis (RA) and periodontal disease (PD) has been the focus of numerous investigations driven by their common pathological features. RA is an autoimmune disease characterized by chronic inflammation, the production of anti-citrullinated proteins antibodies (ACPA) leading to synovial joint inflammation and destruction. PD is a chronic inflammatory condition associated with a dysbiotic microbial biofilm affecting the supporting tissues around the teeth leading to the destruction of mineralized and non-mineralized connective tissues. Chronic inflammation associated with both RA and PD is similar in the predominant adaptive immune phenotype, in the imbalance between pro- and anti-inflammatory cytokines and in the role of smoking and genetic background as risk factors. Structural damage that occurs in consequence of chronic inflammation is the ultimate cause of loss of function and disability observed with the progression of RA and PD. Interestingly, the periodontal pathogen Porphyromonas gingivalis has been implicated in the generation of ACPA in RA patients, suggesting a direct biological intersection between PD and RA. However, more studies are warranted to confirm this link, elucidate potential mechanisms involved, and ascertain temporal associations between RA and PD. This review is mainly focused on recent clinical and translational research intends to discuss and provide an overview of the relationship between RA and PD, exploring the similarities in the immune-pathological aspects and the possible mechanisms linking the development and progression of both diseases. In addition, the current available treatments targeting both RA and PD were revised.

Contribution of biomechanical forces to inflammation-induced bone resorption.

AIM: This study aimed to evaluate the contribution of biomechanical loading to inflammation-induced tissue destruction. MATERIALS AND METHODS: A total of 144 adult Holtzman rats were randomly assigned into four experimental groups: control (C), ligature-induced periodontal disease (P), orthodontic movement (OM), and combination group (OMP). On days 1, 3, 7, and 15, following baseline, nine animals from each experimental group were killed. Bone volume fraction (BVF) and bone mineral density (BMD) were measured using micro-computed tomography. Expression and synthesis profile of cytokines and receptors of inflammation in gingival tissues were evaluated by PCR array assay and multiplex immunoassay. RESULTS: At 15 days, the OMP group presented a significantly (p < 0.05) lower BVF and BMD levels when compared to all the other groups. The OMP group presented the highest number of upregulated protein targets in comparison to the other groups. Furthermore, the gene expression and protein levels of CCL2, CCL3, IL-1ß, IL1-α, IL-18, TNF-α, and VEGF were significantly (p < 0.05) higher in the OMP group when compared to the P group. CONCLUSIONS: In summary, mechanical loading modulates the inflammatory response of periodontal tissues to periodontal disease by increasing the expression of several pro-inflammatory mediators and receptors, which leads to increased bone resorption.

Regulation of Ghrelin Receptor by Periodontal Bacteria In Vitro and In Vivo.

Ghrelin plays a major role in obesity-related diseases which have been shown to be associated with periodontitis. This study sought to analyze the expression of the functional receptor for ghrelin (GHS-R1a) in periodontal cells and tissues under microbial conditions in vitro and in vivo. The GHS-R1a expression in human periodontal cells challenged with the periodontopathogen Fusobacterium nucleatum, in gingival biopsies from periodontally healthy and diseased individuals, and from rats with and without ligature-induced periodontitis was analyzed by real-time PCR, immunocytochemistry, and immunofluorescence. F. nucleatum induced an initial upregulation and subsequent downregulation of GHS-R1a in periodontal cells. In rat experimental periodontitis, the GHS-R1a expression at periodontitis sites was increased during the early stage of periodontitis, but significantly reduced afterwards, when compared with healthy sites. In human gingival biopsies, periodontally diseased sites showed a significantly lower GHS-R1a expression than the healthy sites. The expression of the functional ghrelin receptor in periodontal cells and tissues is modulated by periodontal bacteria. Due to the downregulation of the functional ghrelin receptor by long-term exposure to periodontal bacteria, the anti-inflammatory actions of ghrelin may be diminished in chronic periodontal infections, which could lead to an enhanced periodontal inflammation and tissue destruction.

Long-term evaluation of oral gavage with periodontopathogens or ligature induction of experimental periodontal disease in mice.

OBJECTIVE: To evaluate in long-term periods the destruction of periodontal tissues and bacterial colonization induced by oral gavage with periodontopathogens or ligature experimental periodontal disease models. MATERIAL AND METHODS: Forty-eight C57BL/6 J mice were divided into four groups: group C: negative control; group L: ligature; group G-Pg: oral gavage with Porphyromonas gingivalis; and group G-PgFn: oral gavage with Porphyromonas gingivalis associated with Fusobacterium nucleatum. Mice were infected by oral gavage five times in 2-day intervals. After 45 and 60 days, animals were sacrificed and the immune-inflammatory response in the periodontal tissue was assessed by stereometric analysis. The alveolar bone loss was evaluated by live microcomputed tomography and histometric analysis. qPCR was used to confirm the bacterial colonization in all the groups. Data were analyzed using the Kruskal-Wallis, Wilcoxon, and ANOVA tests, at 5 % of significance level. RESULTS: Ligature model induced inflammation and bone resorption characterized by increased number of inflammatory cells and decreased number of fibroblasts, followed by advanced alveolar bone loss at 45 and 60 days (p < 0.05). Bacterial colonization in groups G-Pg and G-PgFn was confirmed by qPCR but inflammation and bone resorption were not observed (p < 0.05). CONCLUSIONS: The ligature model but not the oral gavage models were effective to induce inflammation and bone loss in long-term periods. Pg colonization was observed in all models of experimental periodontal disease induction, independent of tissue alterations. These mice models of periodontitis validates, compliments, and enhances published PD models that utilize ligature or oral gavage and supports the importance of a successful colonization of a susceptible host, a bacterial invasion into vulnerable tissue, and host-bacterial interactions that lead to tissue destruction. CLINICAL RELEVANCE: The ligature model was an effective approach to induce inflammation and bone loss similar to human periodontitis, but the oral gavage models were not efficient in inducing periodontal inflammation and tissue destruction in the conditions studied. Ligature models can provide a basis for future interventional studies that contribute to the understanding of the disease pathogenesis and the complex host response to microbial challenge.

Effect of Er,Cr:YSGG laser application in the treatment of experimental periodontitis.

The purpose of this study was to evaluate the influence of an erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser in the absence or presence of manual scaling and root planning (SRP) for the treatment of induced periodontitis in rats. Ligatures were placed in the subgingival region of the maxillary first molar. After a 7-day period, the ligatures were removed, and 40 rats were randomly divided into four groups (G), as follows: (GI) no treatment, (GII) scaling and root planning (SRP) with curettes, (GIII) Er,Cr:YSGG laser irradiation and (GIV) SRP with curettes followed by Er,Cr:YSGG laser irradiation. Seven and 30 days after the treatment, the animals were sacrificed and histologic, histometric and immunohistochemistry analyses were performed. All groups showed similar histopathological characteristics during the evaluation period. The histometric analysis was confirmed using Bonferroni and paired t tests. At 7 and 30 days, groups II, III and IV exhibited greater bone formation in the furcation area when compared to group I (p < 0.0001; p < 0.05). During the 7-day period, the groups irradiated with the laser (III and IV) showed a statistically larger new bone area than the group treated with SRP (II) (p < 0.01). Immunohistochemistry analysis revealed that the control group exhibited a higher expression of tartrate-resistant acid phosphatase (TRAP) and the receptor activator of nuclear factor κΒ ligand (RANKL) when compared to groups II, III and IV (p < 0.05). All treatments were able to reduce the inflammatory processes, consequently enabling the repair of periodontal tissues. The results achieved with the application of the Er,Cr:YSGG laser suggest that this laser can stimulate greater bone formation, especially over a shorter period of time.

Reconstruction of the Alveolar Buccal Bone Plate in Compromised Fresh Socket after Immediate Implant Placement Followed by Immediate Provisionalization.

OBJECTIVE: The aim of this clinical report was to reestablish the buccal bone wall after immediate implant placement. The socket defect was corrected with autogenous bone, and a connective tissue graft was removed from the maxillary tuberosity to increase the thickness, height, and width of the buccal bone and gingival tissue followed by immediate provisionalization of the crown during the same operation. CLINICAL CONSIDERATIONS: A 66-year-old patient presented with a hopeless maxillary left central incisor with loss of the buccal bone wall. Atraumatic, flapless extraction was performed, and an immediate implant was placed in the extraction socket followed by preparation of an immediate provisional restoration. Subsequently, immediate reconstruction of the buccal bone plate was performed, using the tuberosity as the donor site, to obtain block bone and connective tissue grafts, as well as particulate bone. Finally, immediate provisionalization of the crown followed by simple sutures was performed. Cone-beam computed tomography and periapical radiographs were taken before and after surgery. After 4 months, the final prosthetic crown was made. After a 2-year follow-up, a satisfactory aesthetic result was achieved with lower treatment time and morbidity. CONCLUSION: This case demonstrates the effective use of immediate reconstruction of the buccal bone wall for the treatment of a hopeless tooth in the maxillary aesthetic area. This procedure efficiently promoted harmonious gingival and bone architecture, recovered lost anatomical structures with sufficient width and thickness, and maintained the stability of the alveolar bone crest in a single procedure. CLINICAL SIGNIFICANCE: If appropriate clinical conditions exist, immediate dentoalveolar restoration may be the most conservative means of reconstructing the buccal bone wall after immediate implant placement followed by immediate provisionalization with predictable healing and lower treatment time.

Biomechanical loading modulates proinflammatory and bone resorptive mediators in bacterial-stimulated PDL cells.

The present study aimed to evaluate in vitro whether biomechanical loading modulates proinflammatory and bone remodeling mediators production by periodontal ligament (PDL) cells in the presence of bacterial challenge. Cells were seeded on BioFlex culture plates and exposed to Fusobacterium nucleatum ATCC 25586 and/or cyclic tensile strain (CTS) of low (CTSL) and high (CTSH) magnitudes for 1 and 3 days. Synthesis of cyclooxygenase-2 (COX2) and prostaglandin E2 (PGE2) was evaluated by ELISA. Gene expression and protein secretion of osteoprotegerin (OPG) and receptor activator of nuclear factor kappa-B ligand (RANKL) were evaluated by quantitative RT-PCR and ELISA, respectively. F. nucleatum increased the production of COX2 and PGE2, which was further increased by CTS. F. nucleatum-induced increase of PGE2 synthesis was significantly (P < 0.05) increased when CTSH was applied at 1 and 3 days. In addition, CTSH inhibited the F. nucleatum-induced upregulation of OPG at 1 and 3 days, thereby increasing the RANKL/OPG ratio. OPG and RANKL mRNA results correlated with the protein results. In summary, our findings provide original evidence that CTS can enhance bacterial-induced syntheses of molecules associated with inflammation and bone resorption by PDL cells. Therefore, biomechanical, such as orthodontic or occlusal, loading may enhance the bacterial-induced inflammation and destruction in periodontitis.

HMGB1 localization during experimental periodontitis.

AIM: This study sought to investigate the in vitro expression profile of high mobility group box 1 (HMGB1) in murine periodontal ligament fibroblasts (mPDL) stimulated with LPS or IL-1ß and in vivo during ligature- or LPS-induced periodontitis in rats. MATERIAL AND METHODS: For the in vivo study, 36 rats were divided into experimental and control groups, and biopsies were harvested at 7-30 d following disease induction. Bone loss and inflammation were evaluated. HMGB1 expression was assessed by immunohistochemistry, qPCR, and Western blot. RESULTS: Significant increases in mPDL HMGB1 mRNA occurred at 4, 8, and 12 h with protein expression elevated by 24 h. HMGB1 mRNA expression in gingival tissues was significantly increased at 15 d in the LPS-PD model and at 7 and 15 d in the ligature model. Immunohistochemical staining revealed a significant increase in the number of HMGB1-positive cells during the experimental periods. CONCLUSION: The results show that PDL cells produce HMGB1, which is increased and secreted extracellularly after inflammatory stimuli. In conclusion, this study demonstrates that HMGB1 may be associated with the onset and progression of periodontitis, suggesting that further studies should investigate the potential role of HMGB1 on periodontal tissue destruction.

Regulation of visfatin by microbial and biomechanical signals in PDL cells.

OBJECTIVES: This in vitro study was established to examine whether visfatin thought to be a link between periodontitis and obesity is produced by periodontal ligament (PDL) cells and, if so, whether its synthesis is modulated by microbial and/or biomechanical signals. MATERIALS AND METHODS: PDL cells seeded on BioFlex® plates were exposed to the oral pathogen Fusobacterium nucleatum ATCC 25586 and/or subjected to biomechanical strain for up to 3 days. Gene expression of visfatin and toll-like receptors (TLR) 2 and 4 was analyzed by RT-PCR, visfatin protein synthesis by ELISA and immunocytochemistry, and NFκB nuclear translocation by immunofluorescence. RESULTS: F. nucleatum upregulated the visfatin expression in a dose- and time-dependent fashion. Preincubation with neutralizing antibodies against TLR2 and TLR4 caused a significant inhibition of the F. nucleatum-upregulated visfatin expression at 1 day. F. nucleatum stimulated the NFκB nuclear translocation. Biomechanical loading reduced the stimulatory effects of F. nucleatum on visfatin expression at 1 and 3 days and also abrogated the F. nucleatum-induced NFκB nuclear translocation at 60 min. Biomechanical loading inhibited significantly the expression of TLR2 and TLR4 at 3 days. The regulatory effects of F. nucleatum and/or biomechanical loading on visfatin expression were also observed at protein level. CONCLUSIONS: PDL cells produce visfatin, and this production is enhanced by F. nucleatum. Biomechanical loading seems to be protective against the effects of F. nucleatum on visfatin expression. CLINICAL RELEVANCE: Visfatin produced by periodontal tissues could play a major role in the pathogenesis of periodontitis and the interactions with obesity and other systemic diseases.

Influence of anti-sclerostin monoclonal antibody in the repair of post-extraction sockets of ovariectomized rats.

OBJECTIVE: This study assessed the impact of an anti-sclerostin monoclonal antibody (Scl-Ab)-based osteoporosis drug on the post-extraction alveolar repair of ovariectomized rats. DESIGN: Fifteen female rats were randomly distributed into three groups: CTR (healthy animals), OST (osteoporosis induced by ovariectomy), and OST+Scl-Ab (osteoporosis induction followed by Scl-Ab treatment). Ovariectomy or sham surgery was performed 30 days before baseline, and Scl-Ab or a vehicle was administered accordingly in the groups. After seven days, all rats underwent the first lower molar extraction and were euthanized 15 days later. Computed microtomography, histological analysis, and collagen content measurement were performed on post-extraction sockets and intact mandibular and maxillary bone areas. RESULTS: Microtomographic analyses of the sockets and mandibles did not reveal significant differences between groups on bone morphometric parameters (p > 0.05), while maxillary bone analyses resulted in better maintenance of bone architecture in OST+Scl-Ab, compared to OST (p < 0.05). Descriptive histological analysis and polarization microscopy indicated better post-extraction socket repair characteristics and collagen content in OST+Scl-Ab compared to OST (p < 0.05). CONCLUSIONS: Scl-Ab-based medication did not accelerate alveolar bone formation but exhibited better post-extraction repair characteristics, and collagen content compared to ovariectomized animals only.

A new hydroxyapatite-alginate-gelatin biocomposite favor bone regeneration in a critical-sized calvarial defect model.

This study aimed to evaluate the osteogenic potential of hydroxyapatite (HA), Alginate (Alg), and Gelatine (Gel) composite in a critical-size defect model in rats. Twenty-four male rats were divided into three groups: a negative control with no treatment (Control group), a positive control treated with deproteinized bovine bone mineral (DBBM group), and the experimental group treated with the new HA-Alg-Gel composite (HA-Alg-Gel group). A critical size defect (8.5mm) was made in the rat's calvaria, and the bone formation was evaluated by in vivo microcomputed tomography analysis (µCT) after 1, 15, 45, and 90 days. After 90 days, the animals were euthanized and histological and histomorphometric analyses were performed. A higher proportion of mineralized tissue/biomaterial was observed in the DBBM group when compared to the HA-Alg-Gel and Control groups in the µCT analysis during all analysis periods. However, no differences were observed in the mineralized tissue/biomaterial proportion observed on day 1 (immediate postoperative) in comparison to later periods of analysis in all groups. In the histomorphometric analysis, the HA-Alg-Gel and Control groups showed higher bone formation than the DBBM group. Moreover, in histological analysis, five samples of the HA-Alg-Gal group exhibited formed bone spicules adjacent to the graft granules against only two of eight samples in the DBBM group. Both graft materials ensured the maintenance of defect bone thickness, while a tissue thickness reduction was observed in the control group. In conclusion, this study demonstrated the osteoconductive potential of HA-Alg-Gel bone graft by supporting new bone formation around its particles.

Stimulation of MMP-1 and CCL2 by NAMPT in PDL cells.

Periodontitis is an inflammatory disease caused by pathogenic microorganisms and characterized by the destruction of the periodontium. Obese individuals have an increased risk of periodontitis, and elevated circulating levels of adipokines, such as nicotinamide phosphoribosyltransferase (NAMPT), may be a pathomechanistic link between both diseases. The aim of this in vitro study was to examine the regulation of periodontal ligament (PDL) cells by NAMPT and its production under inflammatory and infectious conditions. NAMPT caused a significant upregulation of 9 genes and downregulation of 3 genes, as analyzed by microarray analysis. Eight of these genes could be confirmed by real-time PCR: NAMPT induced a significant upregulation of EGR1, MMP-1, SYT7, ITPKA, CCL2, NTM, IGF2BP3, and NRP1. NAMPT also increased significantly the MMP-1 and CCL2 protein synthesis. NAMPT was significantly induced by interleukin-1 ß and the periodontal microorganism P. gingivalis. NAMPT may contribute to periodontitis through upregulation of MMP-1 and CCL2 in PDL cells. Increased NAMPT levels, as found in obesity, may therefore represent a mechanism whereby obesity could confer an increased risk of periodontitis. Furthermore, microbial and inflammatory signals may enhance the NAMPT synthesis in PDL cells and thereby contribute to the increased gingival and serum levels of this adipokine, as found in periodontitis.