Periodontal therapeutics: Current host-modulation agents and future directions

Research progress of the mechanisms and applications of ginsenosides in promoting bone formation

BACKGROUND

Bone deficiency-related diseases caused by various factors have disrupted the normal function of the skeleton and imposed a heavy burden globally, urgently requiring potential new treatments. The multi-faceted role of compounds like ginsenosides and their interaction with the bone microenvironment, particularly osteoblasts can promote bone formation and exhibit anti-inflammatory, vascular remodeling, and antibacterial properties, holding potential value in the treatment of bone deficiency-related diseases and bone tissue engineering.

PURPOSE

This review summarizes the interaction between ginsenosides and osteoblasts and the bone microenvironment in bone formation, including vascular remodeling and immune regulation, as well as their therapeutic potential and toxicity in the broad treatment applications of bone deficiency-related diseases and bone tissue engineering, to provide novel insights and treatment strategies.

METHODS

The literature focusing on the mechanisms and applications of ginsenosides in promoting bone formation before March 2024 was searched in PubMed, Web of Science, Google Scholar, Scopus, and Science Direct databases. Keywords such as "phytochemicals", "ginsenosides", "biomaterials", "bone", "diseases", "bone formation", "microenvironment", "bone tissue engineering", "rheumatoid arthritis", "periodontitis", "osteoarthritis", "osteoporosis", "fracture", "toxicology", "pharmacology", and combinations of these keywords were used.

RESULTS

Ginsenoside monomers regulate signaling pathways such as WNT/β-catenin, FGF, and BMP/TGF-β, stimulating osteoblast generation and differentiation. It exerts angiogenic and anti-inflammatory effects by regulating the bone surrounding microenvironment through signaling such as WNT/β-catenin, NF-κB, MAPK, PI3K/Akt, and Notch. It shows therapeutic effects and biological safety in the treatment of bone deficiency-related diseases, including rheumatoid arthritis, osteoarthritis, periodontitis, osteoporosis, and fractures, and bone tissue engineering by promoting osteogenesis and improving the microenvironment of bone formation.

CONCLUSION

The functions of ginsenosides are diverse and promising in treating bone deficiency-related diseases and bone tissue engineering. Moreover, potential exists in regulating the bone microenvironment, modifying biomaterials, and treating inflammatory-related bone diseases and dental material applications. However, the mechanisms and effects of some ginsenoside monomers are still unclear, and the lack of clinical research limits their clinical application. Further exploration and evaluation of the potential of ginsenosides in these areas are expected to provide more effective methods for treating bone defects.

Periodontal disease and emerging point-of-care technologies for its diagnosis

Periodontal disease (PD), a chronic inflammatory disorder that damages the tooth and its supporting components, is a common global oral health problem. Understanding the intricacies of these disorders, from gingivitis to severe PD, is critical for efficient treatment, diagnosis, and prevention in dental care. Periodontal biosensors and biomarkers are critical in improving oral health diagnostic skills. Clinicians may accomplish early identification, tailored therapy, and efficient tracking of periodontal diseases by using these technologies, ushering in a new age of accurate oral healthcare. Traditional periodontitis diagnostic methods frequently rely on physical probing and visual examinations, necessitating the development of point-of-care (POC) devices. As periodontal disorders necessitate more precise and rapid diagnosis, incorporating novel innovations in biosensors and biomarkers becomes increasingly crucial. These innovations improve our capacity to diagnose, monitor, and adapt periodontal therapies, bringing in the next phase of customized and effective dental healthcare. The review discusses the characteristics and stages of PD, clinical treatment techniques, prominent biomarkers and infection-associated factors that may be employed to determine PD, biomedical sensing, and POC appliances that have been created so far to diagnose stages of PD and its progression profile, as well as predicting future developments in this field.

Computational analysis of curcumin-mediated alleviation of inflammation in periodontitis patients with experimental validation in mice

AIM

Using network pharmacology and experimental validation to explore the therapeutic efficacy and mechanism of curcumin (Cur) in periodontitis treatment.

MATERIALS AND METHODS

Network pharmacology was utilized to predict target gene interactions of Cur-Periodontitis. Molecular docking was used to investigate the binding affinity of Cur for the predicted targets. A mouse model with ligature-induced periodontitis (LIP) was used to verify the therapeutic effect of Cur. Microcomputed tomography (micro-CT) was used to evaluate alveolar bone resorption, while western blotting, haematoxylin-eosin staining and immunohistochemistry were used to analyse the change in immunopathology. SYTOX Green staining was used to assess the in vitro effect of Cur in a mouse bone marrow-isolated neutrophil model exposed to lipopolysaccharide.

RESULTS

Network pharmacology identified 114 potential target genes. Enrichment analysis showed that Cur can modulate the production of neutrophil extracellular traps (NETs). Molecular docking experiments suggested that Cur effectively binds to neutrophil elastase (ELANE), peptidylarginine deiminase 4 (PAD4) and cathepsin G, three enzymes involved in NETs. In LIP mice, Cur alleviated alveolar bone resorption and reduced the expression of ELANE and PAD4 in a time-dependent but dose-independent manner. Cur can directly inhibit NET formation in the cell model.

CONCLUSIONS

Our research suggested that Cur may alleviate experimental periodontitis by inhibiting NET formation.

Antimicrobial and anti-inflammatory effects of BenTooth: A natural product blend of burdock root, persimmon leaf extracts, and quercetin on periodontal disease

Periodontal disease represents a condition that exhibits substantial global morbidity, and is characterized by the infection and inflammation of the periodontal tissue effectuated by bacterial pathogens. The present study aimed at evaluating the therapeutic efficacy of BenTooth, an edible natural product mixture comprising burdock root extract, persimmon leaf extract and quercetin, against periodontitis both in vitro and in vivo. BenTooth was examined for antimicrobial properties and its impact on cellular responses related to inflammation and bone resorption. Its effects were also assessed in a rat model of ligature-induced periodontitis. BenTooth demonstrated potent antimicrobial activity against P. gingivalis and S. mutans. In RAW264.7 cells, it notably diminished the expression of inducible nitric oxide synthase and cyclooxygenase-2, as well as reduced interleukin-6 and tumor necrosis factor-α levels triggered by P. gingivalis-derived lipopolysaccharide. Furthermore, BenTooth inhibited osteoclastogenesis mediated by the receptor activator of nuclear factor κB ligand. In the rat model, BenTooth consumption mitigated the ligature-induced expansion in distance between the cementoenamel junction and the alveolar bone crest and bolstered the bone volume fraction. These results present BenTooth as a potential therapeutic candidate for the prevention and remediation of periodontal diseases.

Evaluation of Immunohistochemical Biomarkers in Diabetic Wistar Rats with Periodontal Disease

BACKGROUND

The association of periodontal disease and diabetes is a subject of intense research in terms of etiopathology and treatment options. This research aimed to evaluate the modulation of the local inflammatory status by two natural extracts, curcumin (Cu) and rutin (R), in an experimentally induced diabetes and periodontal disease in Wistar rats.

METHODS

Fifty Wistar albino rats were randomly assigned to five groups: Control (C), Diabetes-associated Periodontal Disease (DP), Diabetes-associated Periodontal Disease treated with Curcumin (DPCu), Diabetes-associated Periodontal Disease treated with Rutin (DPR), and Diabetes-associated Periodontal Disease treated with both Curcumin and Rutin (DPCuR). Gingival samples were collected from all rats, and immunohistochemical markers CD3, CD20, and CD34 were evaluated to assess the local inflammatory infiltrate. Descriptive statistics were applied (SPSS24 Software, Armonk, NY, USA).

RESULTS

Rutin, alone or combined with Curcumin, reduced CD3-positive cell levels. Curcumin demonstrated superior efficacy in reducing CD20-positive cells. The combination of Curcumin and Rutin had the most important impact on both markers. Curcumin notably increased immature CD34-positive cell levels.

CONCLUSIONS

Curcumin and Rutin, either alone or together, hold potential for reducing local inflammation in diabetes-induced periodontal disease in Wistar rats.

In Vivo Regulation of Active Matrix Metalloproteinase-8 (aMMP-8) in Periodontitis: From Transcriptomics to Real-Time Online Diagnostics and Treatment Monitoring

BACKGROUND

This study investigated in vivo regulation and levels of active matrix metalloproteinase-8 (aMMP-8), a major collagenolytic protease, in periodontitis.

METHODS

Twenty-seven adults with chronic periodontitis (CP) and 30 periodontally healthy controls (HC) were enrolled in immunohistochemistry and transcriptomics analytics in order to assess Treponema denticola (Td) dentilisin and MMP-8 immunoexpression, mRNA expression of MMP-8 and its regulators (IL-1β, MMP-2, MMP-7, TIMP-1). Furthermore, the periodontal anti-infective treatment effect was monitored by four different MMP-8 assays (aMMP-8-IFMA, aMMP-8-Oralyzer, MMP-8-activity [RFU/minute], and total MMP-8 by ELISA) among 12 CP (compared to 25 HC).

RESULTS

Immunohistochemistry revealed significantly more Td-dentilisin and MMP-8 immunoreactivities in CP vs. HC. Transcriptomics revealed significantly elevated IL-1β and MMP-7 RNA expressions, and MMP-2 RNA was slightly reduced. No significant differences were recorded in the relatively low or barely detectable levels of MMP-8 mRNAs. Periodontal treatment significantly decreased all MMP-8 assay levels accompanied by the assessed clinical indices (periodontal probing depths, bleeding-on-probing, and visual plaque levels). However, active but not total MMP-8 levels persisted higher in CP than in periodontally healthy controls.

CONCLUSION

In periodontal health, there are low aMMP-8 levels. The presence of Td-dentilisin in CP gingivae is associated with elevated aMMP-8 levels, potentially contributing to a higher risk of active periodontal tissue collagenolysis and progression of periodontitis. This can be detected by aMMP-8-specific assays and online/real-time aMMP-8 chair-side testing.

Exploring the Potential of Micro-Immunotherapy in the Treatment of Periodontitis

Periodontitis, characterized by the progressive destruction of dental support tissues due to altered immune responses, poses a significant concern for public health. This condition involves intricate interactions between the immune response and oral microbiome, where innate and adaptive immune responses, with their diverse cell populations and inflammatory mediators, play crucial roles in this immunopathology. Indeed, cytokines, chemokines, growth factors, and immune cells perform key functions in tissue remodeling. Focusing on periodontal therapies, our attention turns to micro-immunotherapy (MI), employing low doses (LDs) and ultra-low doses (ULDs) of immunological signaling molecules like cytokines, growth factors, and hormones. Existing studies across various fields lay the groundwork for the application of MI in periodontitis, highlighting its anti-inflammatory and regenerative potential in soft tissue models based on in vitro research. In summary, this review underscores the versatility and potential of MI in managing periodontal health, urging further investigations to solidify its clinical integration. MI supports an innovative approach by modulating immune responses at low doses to address periodontitis.

Exploring the Efficacy of Novel Therapeutic Strategies for Periodontitis: A Literature Review

Periodontitis, a prevalent oral condition, is facing difficulties in therapeutic approaches, sometimes leading to failure. This literature review was conducted to investigate the diversity of other therapeutic approaches and their potential contributions to the successful management of the disease. This research scrutinized the alterations in microbial diversity and imbalances in crucial microbial species, which contribute significantly to the pathogenesis of periodontitis. Within the limitations of this study, we highlight the importance of understanding the treatment plan's role in periodontitis disease, opening the way for further research and innovative treatment plans to mitigate the impact of periodontitis on oral health. This will aid both healthcare professionals and patients in preventing and effectively treating periodontitis, ultimately improving oral health outcomes and overall systemic health and well-being.

J-shaped association between systemic immune-inflammation index and periodontitis: Results from NHANES 2009-2014

BACKGROUND

To examine the relationship between the systemic immune-inflammation index (SII) and periodontitis and to investigate possible effect modifiers.

METHODS

Data used in the present cross-sectional study are from the National Health and Nutrition Examination Survey (NHANES) 2009-2014 (N = 10,301). The SII was calculated using the following formula: (neutrophils count × platelet count)/lymphocytes count. The category of periodontitis was defined by the Centers for Disease Control and Prevention and American Academy of Periodontology (CDC/AAP) classification. We employed natural cubic spline and multivariable logistic regression analyses to evaluate the associations of the SII with periodontitis.

RESULTS

The associations between SII and periodontal health followed a J-shape (p < 0.001). The risk of periodontitis tended to reduce with the increment of log2(SII) in participants with log2(SII) ≤ 8.66 (odds radio [OR] = 0.83; 95% CI: 0.69-0.999), especially among non-Hispanic Whites (OR = 0.70; 95% CI: 0.52-0.95), and increased with the increment of log2(SII) in participants with log2(SII) > 8.66 (OR = 1.19; 95% CI: 1.02-1.38). A similar trend was also observed between the SII and the number of sites with probing pocket depth (PPD) ≥4 mm and clinical attachment loss (CAL) ≥ 3 or 5 mm. Furthermore, we found a significantly stronger correlation between lymphocytes and either neutrophils or platelets in individuals with log2(SII) > 8.66, as opposed to those with log2(SII) ≤ 8.66.

CONCLUSIONS

There is a J-shaped association between SII and periodontitis in US adults, with an inflection point of log2(SII) at 8.66, which may provide potential adjunctive treatment strategies for periodontitis with different immune response states. Further prospective trials are still required to confirm our findings.

Delving into Matrix Metalloproteinase-1 (MMP-1) and its Significance in Periodontal Diseases

Matrix metalloproteinase-1 (MMP-1) plays a pivotal role in the pathogenesis of periodontal diseases, particularly periodontitis, by virtue of its collagenolytic activity targeting collagen type I, the primary component of periodontal tissues. This review abstract elucidates the intricate involvement of MMP-1 in periodontal tissue homeostasis and its dysregulation in disease states. Elevated MMP-1 levels, observed in gingival tissues and crevicular fluid of individuals with periodontitis, correlate with the degradation of collagen fibers within the periodontium. This degradation contributes to the detachment of teeth from surrounding tissues and exacerbates alveolar bone resorption, hallmark features of periodontal breakdown. Therapeutically, targeting MMP-1 activity emerges as a promising strategy, prompting ongoing research into MMP inhibitors and host modulation therapies. Understanding MMP-1's nuanced role in periodontal diseases paves the way for personalized treatment approaches and holds promise in reshaping periodontal disease management for improved patient outcomes and periodontal health.

Association Between Number of Missing Teeth and Hyperlipidemia: The TCLSIH Cohort Study

Background

To explore the association between the number of missing teeth and the prevalence of hyperlipidemia in a Chinese adult population.

Methods

13,932 adults were investigated in the TCLSIH cohort study. The number of missing teeth was determined at baseline through a self-reported questionnaire, and then classified into three categories: 0, 1-2, and ≥3. We defined hyperlipidemia as total cholesterol (TC) ≥ 5.17 mmol/L or triglycerides (TG) ≥ 1.7 mmol/L or low-density lipoprotein (LDL) cholesterol ≥ 3.37 mmol/L or a self-report of physician-diagnosed hyperlipidemia during follow-up visits. Cox proportional-hazards regression models were employed to assess the relationship between the number of missing teeth and incident hyperlipidemia.

Results

A total of 6756 first-incident cases of hyperlipidemia occurred during 42,048 person-years of follow-up (median follow-up, 4.2 years). After adjusted confounders, multivariable HRs and 95% CI for incident of hyperlipidemia across the categories of missing teeth were as follows: in male participants, 1.00 (reference), 1.10 (0.98, 1.22), and 1.03 (0.91, 1.16) (P for trend = 0.30); in female participants, 1.00 (reference), 1.09 (0.99, 1.19), and 1.18 (1.04, 1.33) (P for trend < 0.01).

Conclusion

The number of missing teeth is associated with an increased risk of hyperlipidemia in female participants but not in male participants. Systemic chronic inflammation may potentially mediate this association.

Association between periodontitis and inflammatory comorbidities: The common role of innate immune cells, underlying mechanisms and therapeutic targets

Periodontitis, which is related to various systemic diseases, is a chronic inflammatory disease caused by periodontal dysbiosis of the microbiota. Multiple factors can influence the interaction of periodontitis and associated inflammatory disorders, among which host immunity is an important contributor to this interaction. Innate immunity can be activated aberrantly because of the systemic inflammation induced by periodontitis. This aberrant activation not only exacerbates periodontal tissue damage but also impairs systemic health, triggering or aggravating inflammatory comorbidities. Therefore, innate immunity is a potential therapeutic target for periodontitis and associated inflammatory comorbidities. This review delineates analogous aberrations of innate immune cells in periodontitis and comorbid conditions such as atherosclerosis, diabetes, obesity, and rheumatoid arthritis. The mechanisms behind these changes in innate immune cells are discussed, including trained immunity and clonal hematopoiesis of indeterminate potential (CHIP), which can mediate the abnormal activation and myeloid-biased differentiation of hematopoietic stem and progenitor cells. Besides, the expansion of myeloid-derived suppressor cells (MDSCs), which have immunosuppressive and osteolytic effects on peripheral tissues, also contributes to the interaction between periodontitis and its inflammatory comorbidities. The potential treatment targets for relieving the risk of both periodontitis and systemic conditions are also elucidated, such as the modulation of innate immunity cells and mediators, the regulation of trained immunity and CHIP, as well as the inhibition of MDSCs' expansion.

Enhancing osteogenic differentiation of MC3T3-E1 cells during inflammation using UPPE/β-TCP/TTC composites via the Wnt/β-catenin pathway

Periodontitis can lead to defects in the alveolar bone, thus increasing the demand for dependable biomaterials to repair these defects. This study aims to examine the pro-osteogenic and anti-bacterial properties of UPPE/β-TCP/TTC composites (composed of unsaturated polyphosphoester [UPPE], β-tricalcium phosphate [β-TCP], and tetracycline [TTC]) under an inflammatory condition. The morphology of MC3T3-E1 cells on the composite was examined using scanning electron microscopy. The toxicity of the composite to MC3T3-E1 cells was assessed using the Alamar-blue assay. The pro-osteogenic potential of the composite was assessed through ALP staining, ARS staining, RT-PCR, and WB. The antimicrobial properties of the composite were assessed using the zone inhibition assay. The results suggest that: (1) MC3T3-E1 cells exhibited stable adhesion to the surfaces of all four composite groups; (2) the UPPE/β-TCP/TTC composite demonstrated significantly lower toxicity to MC3T3-E1 cells; and (3) the UPPE/β-TCP/TTC composite had the most pronounced pro-osteogenic effect on MC3T3-E1 cells by activating the WNT/β-catenin pathway and displaying superior antibacterial properties. UPPE/β-TCP/TTC, as a biocomposite, has been shown to possess antibacterial properties and exhibit excellent potential in facilitating osteogenic differentiation of MC3T3-E1 cells.

Exploring natural anthraquinones as potential MMP2 inhibitors: A computational study

OBJECTIVE

Matrix metalloproteinase-2 (MMP2) plays a significant role in cleaving extracellular matrix components, leading to many cancer cells' progression and invasion behavior. Therefore, MMP2 inhibition may hold promise for cancer treatment. Anthraquinones have shown antineoplastic effects, some of which have been used in clinical practice as anticancer drugs. This study used a computational drug discovery approach to assess the possible inhibitory effects of selected anthraquinones on MMP2. The results were then compared with that of Captopril, which was considered a standard drug.

METHODS

This study used the AutoDock 4.0 tool to evaluate the binding affinity of 21 anthraquinones to the MMP2 catalytic domain. The most favorable scores based on the Gibbs free binding energy scores were given to the highest-ranked ligands. The Discovery Studio Visualizer tool illustrated interactions between MMP2 residues and top-ranked anthraquinones.

RESULTS

A total of 12 anthraquinones were identified with ΔGbinding scores less than - 10 kcal/mol. Pulmatin (Chrysophanol-8-glucoside) was the most potent MMP2 inhibitor, with a ΔGbinding score of - 12.91 kcal/mol. This anthraquinone was able to restrict MMP2 activity within a picomolar range.

CONCLUSION

MMP2 inhibition by anthraquinones, notably Pulmatin, may be a useful therapeutic approach for cancer treatment.

Recent Advances in Functionalized Electrospun Membranes for Periodontal Regeneration

Periodontitis is a global, multifaceted, chronic inflammatory disease caused by bacterial microorganisms and an exaggerated host immune response that not only leads to the destruction of the periodontal apparatus but may also aggravate or promote the development of other systemic diseases. The periodontium is composed of four different tissues (alveolar bone, cementum, gingiva, and periodontal ligament) and various non-surgical and surgical therapies have been used to restore its normal function. However, due to the etiology of the disease and the heterogeneous nature of the periodontium components, complete regeneration is still a challenge. In this context, guided tissue/bone regeneration strategies in the field of tissue engineering and regenerative medicine have gained more and more interest, having as a goal the complete restoration of the periodontium and its functions. In particular, the use of electrospun nanofibrous scaffolds has emerged as an effective strategy to achieve this goal due to their ability to mimic the extracellular matrix and simultaneously exert antimicrobial, anti-inflammatory and regenerative activities. This review provides an overview of periodontal regeneration using electrospun membranes, highlighting the use of these nanofibrous scaffolds as delivery systems for bioactive molecules and drugs and their functionalization to promote periodontal regeneration.

Increasing fibroblasts and gingival collagen density in periodontitis rats by using cassava leaf extract

Objectives

Porphyromonas gingivalis, as the main etiology of periodontitis, causes inflammation in the periodontal tissue, which triggers the immune response, fibroblast decline, and collagen destruction, generating attachment loss. Fibroblasts and collagen perform a fundamental role in the repair process of periodontal tissue. This study examined the potential of cassava leaf extract in increasing the quantity of fibroblasts and collagen density in the gingiva of rats with periodontitis.

Methods

A posttest-only control group was used in this study. The experiment involved 24 male Wistar rats divided into four different groups: control group, group induced by P. gingivalis and given aquadest, group induced by P. gingivalis and given metronidazole, and group induced by P. gingivalis and given cassava leaf extract. Gingival tissue was taken after euthanasia, after which histological preparations were made, and fibroblasts and collagen were observed.

Results

One-way analysis of variance revealed that the collagen density and fibroblasts quantity showed a notable difference between each group (p < 0.05), and interestingly, there was no significant difference between metronidazole and cassava leaf extract in the least significant difference test results (p > 0.05).

Conclusion

Cassava leaf extract has the potential to increase fibroblast quantity and collagen density in the gingiva of periodontitis rat models.

Curcumin attenuates replicative senescence in human dental follicle cells and restores their osteogenic differentiation

OBJECTIVE

This study aimed to examine the therapeutic effects of curcumin against replicative senescence in dental follicle cells (DFCs).

METHODS

Human DFCs were cultured in Dulbecco's Modified Eagle Medium with growth supplements. Replicative senescence in DFCs at different passages was assessed using β-galactosidase activity assay. Cell proliferation and size of DFCs at different passages were determined by CCK-8 kit and microscopy method, respectively. In addition, curcumin's effect on replicative senescence, cell proliferation, and size of DFCs at different passages was analyzed. Using western-blot analysis and siRNA-mediated gene silencing, we determined the molecular mechanisms involved in curcumin's effect against replicative senescence and osteogenic differentiation in DFCs at different passages.

RESULTS

We observed decreased proliferation and increased cell size and replicative senescence in cultured human DFCs at higher passages. Intriguingly, despite not showing any effect on cell size, curcumin (50 μM) significantly restored proliferation ability in DFCs and inhibited their replicative senescence. Concerning mechanisms, we found that curcumin inhibits replicative senescence in DFCs via down-regulation of senescence markers (P16 & P21) and restoration of proliferation markers (E2F1 & P53). Additionally, curcumin also rescued the osteogenic differentiation potential in higher-passage DFCs via restoration of osteogenic markers RUNX2 and OPN.

CONCLUSION

Our findings reveal for the first time that curcumin could act as a potential anti-senescence therapeutic for DFCs via regulation of proliferation, senescence, and osteogenic differentiation markers.

Regulatory B cells induced by interleukin-35 inhibit inflammation and alveolar bone resorption in ligature-induced periodontitis

BACKGROUND

Regulatory B cells (Bregs) have been reported to suppress immune responses and alveolar bone loss in murine periodontitis models. These cells could be induced by interleukin (IL)-35 which is increased upon periodontal inflammation. Thus, this study aimed to explore the role of Bregs induced by IL-35 in periodontitis.

METHODS

Experimental periodontitis was induced in mice by ligature. Two weeks after ligation, the test group was systemically treated with IL-35 for 1 week. Four weeks after ligation, all mice were euthanized, and alveolar bone loss was evaluated by microcomputed tomography. Cytokines associated with periodontitis were analyzed using reverse transcription-quantitative polymerase chain reaction and enzyme-linked immunosorbent assay. Bregs in spleens, cervical lymph nodes, and periodontal tissues were detected by flow cytometry and immunofluorescence staining.

RESULTS

In the mouse model of periodontitis, IL-35 induced the expansion of CD1dhi CD5+ B10 cells with increased interleukin-10 (IL-10) and IL-35 production. IL-35 administration also attenuated alveolar bone loss and reduced the levels of proinflammatory cytokines in situ.

CONCLUSIONS

Following ligature-induced periodontitis in mice, IL-35 inhibited periodontal inflammation and alveolar bone resorption at least partially through the induction of B10 cells and IL-35+ Bregs.

Influence of locally delivered doxycycline on the clinical and molecular inflammatory status of intrabony defects prior to periodontal regeneration: A double-blind randomized controlled trial

OBJECTIVES

To test the effect of locally delivered doxycycline (DOX) administered 2 weeks prior to minimally invasive periodontal regeneration in terms of presurgical inflammatory status and cytokine expression profile in the gingival crevicular fluid (GCF). Secondary aim was to assess the early wound healing index (EHI) at 2 weeks after surgery.

BACKGROUND

It is hypothesized that healing after periodontal regeneration is dependent on preoperative soft tissue condition, and that local antibiotics may improve the site-specific inflammatory status at short time.

METHODS

Sites associated with periodontal intrabony defects requiring regenerative surgery and showing bleeding on probing (BoP) were included. At T0, experimental sites were randomly treated with subgingival instrumentation with or without topic DOX application. After 2 weeks (T1), defects were approached by means of minimally invasive surgical technique. GCF was sampled at both T0 and T1 for inflammatory biomarker analysis. Two weeks after surgery, the EHI was evaluated (T2).

RESULTS

Forty-four patients were included. At T1, the number of BoP+ sites was statistically significantly less in the test group (27.3% vs. 72.7%; p < .01). The total amount of interleukin (IL)-1β (p < .001), matrix-metalloproteinases (MMP)-8 (p < .001), and MMP-9 (p = .010) in the GCF significantly decreased in the test group at T1, with relevant differences compared to controls. At T2, the EHI had an average value of 1.45 ± 0.86 in the test group while in the control, it was 2.31 ± 1.43 (p = .027). A statistically significantly positive correlation was observed between the amount of IL-1β and MMP-9 and EHI scores.

CONCLUSIONS

Within the limitations of this study, sites treated with DOX showed improved clinical and molecular inflammatory parameters before surgery, as well as soft tissue healing 2 weeks after surgery.

Bifidobacterium animalis subspecies lactis HN019 can reduce the sequelae of experimental periodontitis in rats modulating intestinal parameters, expression of lipogenic genes, and levels of hepatic steatosis

OBJECTIVE

To determine whether Bifidobacterium animalis subspecies lactis HN019 (B. lactis HN019) can reduce the sequelae of experimental periodontitis (EP) in rats modulating systemic parameters.

BACKGROUND

This study evaluated the effects of probiotic therapy (PROB) in the prevention of local and systemic damage resulting from EP.

METHODS

Forty-eight rats were allocated into four groups: C (control), PROB, EP, and EP-PROB. PROB (1 × 1010  CFU/mL) administration lasted 8 weeks and PE was induced on the 7th week by placing ligature on the animals' lower first molars. All animals were euthanized in the 9th week of the experiment. Biomolecular analyses, RT-PCR, and histomorphometric analyses were performed. The data obtained were analyzed statistically (ANOVA, Tukey, p < .05).

RESULTS

The EP group had higher dyslipidemia when compared to the C group, as well as higher levels of insulin resistance, proteinuria levels, percentages of systolic blood pressure, percentage of fatty hepatocytes in the liver, and expression of adipokines was up-regulated (LEPR, NAMPT, and FABP4). All these parameters (except insulin resistance, systolic blood pressure, LEPR and FABP4 gene expression) were reduced in the EP-PROB group when compared to the EP group. The EP group had lower villus height and crypt depth, as well as a greater reduction in Bacteroidetes and a greater increase in Firmicutes when compared to the EP-PROB group. Greater alveolar bone loss was observed in the EP group when compared to the EP-PROB group.

CONCLUSION

Bifidobacterium lactis HN019 can reduce the sequelae of EP in rats modulating intestinal parameters, attenuating expression of lipogenic genes and hepatic steatosis.

Effect of doxycycline doped nanoparticles on osteogenic/cementogenic and anti-inflammatory responses of human cells derived from the periodontal ligament

OBJECTIVES

This work aimed to evaluate if doxycycline-doped polymeric nanoparticles possessed any anti-inflammatory effect and promote osteogenic/cementogenic differentiation of stem cells from human periodontal ligament (PDLSCs).

METHODS

The polymeric nanoparticles (NPs) were produced by a polymerization/precipitation process and doped with doxycycline (Dox-NPs). PDLSCs were cultured in the presence or absence of the NPs under osteogenic medium or IL-1β treatment. Cells' differentiation was assessed by gene expression analysis of osteogenic/cementogenic markers alkaline phosphatase (ALP) and Runt-related transcription factor 2 (RUNX2). An anti-inflammatory effect was also ascertained by analyzing IL-1β gene expression. Adipogenic and chondrogenic differentiation was used to confirm the multipotency of PDLSCs.

RESULTS

Gene expression of ALP and RUNX2 in PDLSCs was significantly upregulated by the osteogenic medium (ALP: p<0.001; RUNX2: p = 0.005) while Dox-NPs further enhanced ALP gene expression of PDLSCs treated with the osteogenic medium. Furthermore, Dox-NPs suppressed the up-regulation of IL-1β when cells were subjected to an inflammatory challenge.

CONCLUSIONS

Dox-NPs enhanced PDLSCs differentiation into osteoblasts/cementoblasts lineages while providing an anti-inflammatory effect.

CLINICAL SIGNIFICANCE

Due to their biocompatibility as well as anti-inflammatory and osteogenic/cementogenic effects, Dox-NPs are potential candidates for being used in periodontal regeneration.

A novel modified-curcumin 2.24 resolves inflammation by promoting M2 macrophage polarization

To assess resolving-like activity by a novel chemically-modified curcumin (CMC2.24) in a "two-hit" model of diabetes-associated periodontitis. Macrophages from rats were cultured in the presence/absence of either Lipopolysaccharide (LPS, 1st hit); or advanced-glycation-end products (AGE, 2nd hit); or both combined. CMC2.24 was added as treatment. The conditioned media were analyzed for MMP-9, cytokines (IL-1β, IL-6, TNF-α), resolvins (RvD1, RvE1, lipoxin A4), and soluble receptor for AGE (sRAGE). The phenotypes of M1/M2 macrophage were analyzed by flow cytometry. Both LPS/AGE-alone, and two-combined, dramatically increased the secretion of MMP-9 by macrophages. CMC2.24 "normalized" the elevated levels of MMP-9 under all conditions. Moreover, CMC2.24 significantly reduced the secretion of IL-1β and IL-6 with a fewer effects on TNF-α. Importantly, CMC2.24 increased RvD1 and sRAGE secretion by macrophages exposed to LPS/AGE; and both treatment groups exhibited increased M2 relative to M1 populations. Furthermore, scatter-diagram showed the macrophages gradually shifted from M1 towards M2 with CMC2.24-treated, whereas LPS/AGE-alone groups remained unchanged. CMC2.24 "normalized" cytokines and MMP-9, but also enhanced RvD1 and sRAGE in macrophages. Crucially, CMC2.24 appears to be a potent inhibitor of the pro-inflammatory M1 phenotype; and a promotor of the pro-resolving M2 phenotype, thus acting like a crucial "switch" to reduce inflammation.

Enamel Matrix Derivative Suppresses Chemokine Expression in Oral Epithelial Cells

Epithelial cells in periodontitis patients increasingly express chemokines, suggesting their active involvement in the inflammatory process. Enamel matrix derivative (EMD) is an extract of porcine fetal tooth germs clinically applied to support the regrowth of periodontal tissues. Periodontal regeneration might benefit from the potential anti-inflammatory activity of EMD for epithelial cells. Our aim was, therefore, to set up a bioassay where chemokine expression is initiated in the HSC2 oral squamous carcinoma cell line and then test EMD for its capacity to lower the inflammatory response. To establish the bioassay, HSC2 cells being exposed to TNFα and LPS from E. coli (Escherichia coli) or P. gingivalis (Porphyromonas gingivalis) were subjected to RNAseq. Here, TNFα but not LPS caused a robust increase of chemokines, including CXCL1, CXCL2, CXCL8, CCL5, and CCL20 in HSC2 cells. Polymerase chain reaction confirmed the increased expression of the respective chemokines in cells exposed to TNFα and IL-1β. Under these conditions, EMD reduced the expression of all chemokines at the transcriptional level and CXCL8 by immunoassay. The TGF-β receptor type I kinase-inhibitor SB431542 reversed the anti-inflammatory activity. Moreover, EMD-activated TGF-β-canonical signaling was visualized by phosphorylation of smad3 and nuclear translocation of smad2/3 in HSC2 cells and blocked by SB431542. This observation was confirmed with primary oral epithelial cells where EMD significantly lowered the SB431542-dependent expression of CXCL8. In summary, our findings suggest that TGF-β signaling mediates the effects of EMD to lower the forced expression of chemokines in oral epithelial cells.

Periodontal and cardiovascular therapies modify specialized pro-resolving lipid mediator (sPRLM) (LPXA4, PD1, RvE1, RvD1, and MaR1)-mediated pathway: the first pilot clinical study

OBJECTIVES

Cardiovascular disease (CVD) and periodontal disease have a common pathogenesis with inflammation and resolution steps. Although the relationships among periodontal disease, CVD, and specialized pro-resolving lipid mediator (sPRLM)s are well known, there is no study about the combined effects of cardiovascular and periodontal treatments on sPRLM levels. It was aimed to evaluate the effects of periodontal and cardiovascular therapies on sPRLMs (lipoxin A4, protectin (PD)1, resolvin (Rv) E1, RvD1, and maresin (MaR)1) in patients with CVD and periodontal disease.

METHODS

This observational study consisted of fifty-five patients with CVD and mild or moderate periodontitis. The clinical periodontal parameters (plaque index, gingival index, probing pocket depth, percentage of bleeding on probing, and clinical attachment level) and blood and unstimulated total saliva samples were obtained at baseline, at 3 months (following only cardiovascular therapy), and at 6 months (following cardiovascular and periodontal therapies). The blood count and serum levels of cardiometabolic biomarkers (white blood cell, neutrophil/lymphocyte, serum total cholesterol (TC), triglyceride, and low and high-density lipoprotein (HDL) levels) were evaluated. sPRLMs were evaluated by ELISA.

RESULTS

There were significant decreases in body mass index, clinical periodontal parameters, WBC, LDL, PD1, and RvD1 at 6 months compared to baseline. The decreases in TC/HDL, RvE1, and MaR1 levels were significant at 3 and 6 months compared to baseline (p < 0.05).

CONCLUSION(S)

The combination of cardiovascular and periodontal treatments leads to significant reductions in clinical periodontal and cardiometabolic parameters and sPRLMs.

CLINICAL RELEVANCE

Our report, which is the first in their field, suggested that cardiovascular and periodontal therapies provide an important contribution via decreasing the periodontal and atherosclerotic inflammation modulating sPRLMs. This finding will be a big step toward increasing the quality of life in these patients by drawing attention to importance of public health associated with oral hygiene, periodontal health, and systemic phase of periodontal treatment.

Diabetes mellitus promotes susceptibility to periodontitis-novel insight into the molecular mechanisms

Diabetes mellitus is a main risk factor for periodontitis, but until now, the underlying molecular mechanisms remain unclear. Diabetes can increase the pathogenicity of the periodontal microbiota and the inflammatory/host immune response of the periodontium. Hyperglycemia induces reactive oxygen species (ROS) production and enhances oxidative stress (OS), exacerbating periodontal tissue destruction. Furthermore, the alveolar bone resorption damage and the epigenetic changes in periodontal tissue induced by diabetes may also contribute to periodontitis. We will review the latest clinical data on the evidence of diabetes promoting the susceptibility of periodontitis from epidemiological, molecular mechanistic, and potential therapeutic targets and discuss the possible molecular mechanistic targets, focusing in particular on novel data on inflammatory/host immune response and OS. Understanding the intertwined pathogenesis of diabetes mellitus and periodontitis can explain the cross-interference between endocrine metabolic and inflammatory diseases better, provide a theoretical basis for new systemic holistic treatment, and promote interprofessional collaboration between endocrine physicians and dentists.

Age differences in the effects of multi-component periodontal treatments on oral and metabolic health among people with diabetes mellitus: A meta-epidemiological study

OBJECTIVE

To explore the age differences in the effects of multi-component periodontal treatments on oral and metabolic indicators among individuals with periodontitis and diabetes.

DATA

Trials reporting the effects of multi-component periodontal treatments on oral and metabolic indicators among participants aged 18 and above with periodontitis and diabetes were included.

SOURCES

Six databases (PubMed/Medline, Embase, CINHAL, Web of Science, Cochrane Library, and ProQuest) were searched from database inception to August 2022.

STUDY SELECTION

Two reviewers selected the included studies independently. We used bivariate and multivariate meta-regression models to examine the association between age and treatment effect size. The primary outcomes were changes in probing depth (PD), clinical attachment level (CAL), and hemoglobin A1c (HbA1c).

RESULTS

A total of 18,067 articles were identified in the database search. Of these, 115 trials (119 articles) met inclusion criteria. The mean age of participants was 58 years old, ranging from 35 to 73 years. The pooled evidence demonstrated that multi-component periodontal treatment significantly reduced PD (g=0.929 [0.689-1.169], I2=94.1%), CAL (g=0.879 [0.669-1.089], I2=92.1%), and HbA1c (g=0.603 [0.443-0.763], I2=87.5%). A significant decreasing trend was observed in the effect size for PD (P for trend = 0.020) and CAL (P for trend = 0.028) as age increases. Results from multivariate meta-regression showed that mean age was associated with a smaller effect size for PD (β=-0.123 [0.041], P = 0.004) and CAL (β=-0.159 [0.055], P = 0.006). Compared to their younger counterparts, the effect size for HbA1c was smaller among participants aged 55 and older (β=-0.792 [0.322], P = 0.017).

CONCLUSIONS

Multi-component periodontal treatments may be more effective in younger populations in terms of effects on PD, CAL, and HbA1c.

CLINICAL SIGNIFICANCE

Our study highlights the importance of early intervention and tailored treatment approaches. Clinicians should take into account the patient's age when developing periodontal treatment plans and may need to employ more aggressive or personalized strategies for older adults to achieve optimal outcomes.

Roles of specialized pro-resolving mediators and omega-3 polyunsaturated fatty acids in periodontal inflammation and impact on oral microbiota

Periodontitis is a chronic inflammatory disease induced by dysbiotic dental biofilms. Management of periodontitis is primarily anti-bacterial via mechanical removal of bacterial biofilm. The successful resolution requires wound healing and tissue regeneration, which are not always achieved with these traditional methods. The discovery of specialized pro-resolving mediators (SPMs), a class of lipid mediators that induce the resolution of inflammation and promote local tissue homeostasis, creates another option for the treatment of periodontitis and other diseases of chronic inflammation. In this mini-review, we discuss the host-modulatory effects of SPMs on periodontal tissues and changes in the taxonomic composition of the gut and oral microbiome in the presence of SPMs and SPM precursor lipids. Further research into the relationship between host SPM production and microbiome-SPM modification has the potential to unveil new diagnostic markers of inflammation and wound healing. Expanding this field may drive the discovery of microbial-derived bioactive therapeutics to modulate immune responses.

Illuminating the oral microbiome and its host interactions: animal models of disease

Periodontitis and caries are driven by complex interactions between the oral microbiome and host factors, i.e. inflammation and dietary sugars, respectively. Animal models have been instrumental in our mechanistic understanding of these oral diseases, although no single model can faithfully reproduce all aspects of a given human disease. This review discusses evidence that the utility of an animal model lies in its capacity to address a specific hypothesis and, therefore, different aspects of a disease can be investigated using distinct and complementary models. As in vitro systems cannot replicate the complexity of in vivo host-microbe interactions and human research is typically correlative, model organisms-their limitations notwithstanding-remain essential in proving causality, identifying therapeutic targets, and evaluating the safety and efficacy of novel treatments. To achieve broader and deeper insights into oral disease pathogenesis, animal model-derived findings can be synthesized with data from in vitro and clinical research. In the absence of better mechanistic alternatives, dismissal of animal models on fidelity issues would impede further progress to understand and treat oral disease.

The yawning gap: Waiting for cariology to germinate whilst periodontology is fruiting

INTRODUCTION

The aim of this study is to investigate whether periodontology and cariology receive equal emphasis in dental education at two moments in time, thirteen years apart.

MATERIALS AND METHODS

An online search was conducted in Nov 2021 of all the dental schools in ten English-language speaking countries (U.S., Canada, U.K., Ireland, South Africa, Australia, New Zealand, Singapore, Hong Kong, and Malaysia) to identify departments/divisions in the disciplines of periodontology, cariology, and conservative/restorative/operative dentistry. The results were then compared against the findings of a similar investigation that was conducted from July to October 2008.

RESULTS

Of the 126 dental schools identified in 2021, information was available for 93 dental schools. Of these 93 schools, only 10 listed departments/divisions/disciplines of cariology, whereas 83 and 86 schools had listed periodontology and conservative/restorative/operative dentistry, respectively. Despite a doubling of the number of dental schools with a department/division/discipline of cariology from 2008 to 2021, the absolute gap in the number of departments/divisions/disciplines in the other two disciplines compared to cariology had widened during the thirteen years. In 2008, there were 70 more departments/divisions/disciplines in periodontology compared to cariology departments/divisions/disciplines. In 2021, there were 73 more departments/divisions/disciplines in periodontology. Additional information on research output was available for 90 dental schools in 2021, where 30 schools self-identified as undertaking cariology research, whereas 68 and 47 schools undertook research in periodontology and conservative/restorative/operative dentistry, respectively.

CONCLUSIONS

Dental education does not give equal emphasis to periodontology and cariology, and the discipline of cariology is grossly neglected.

Antimicrobial Efficacy of Blended Essential Oil and Chlorhexidine against Periodontal Pathogen (P.gingivalis)-An In Vitro Study

Background

Essential oils (EOs) have a considerable amount of therapeutic and preventive effect in treating dental diseases due to their wider potential as antibacterial and anti-inflammatory agents. EOs like virgin coconut oil, eucalyptus oil, peppermint oil thyme oil, and clove oil, when used in combination, may further have enhanced antimicrobial effects. However, limited information exists on the synergistic effect of these oils when used in combination, especially on the primary periodontal pathogen Porphyromonas gingivalis.

Aim

The current study aims to compare the antimicrobial efficacy of commercially available EO on the periodontal pathogen, P. gingivalis, in comparison to chlorhexidine (CHX).

Materials and Methods

Antimicrobial efficacy of EO and CHX was assessed at various concentrations against the periodontal pathogen P. gingivalis, by evaluating the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC).

Results

P. gingivalis was seen to be sensitive at a MIC of 100 μg/ml and 50 μg/ml concentration of the EO, which is regarded as the MIC of EO against P. gingivalis and CHX effectively inhibited microbial growth at 0.4 μg/ml.

Conclusion

A combination of EOs possesses a potent antibacterial activity against P. gingivalis, and the antibacterial efficacy increases with increasing concentration of EOs.

Choline and geranic acid (CAGE) ionic liquids inhibit both elastase activity and growth of oral bacteria

Choline and geranic acid (CAGE) ionic liquids have recently been shown to have applications in the delivery of macromolecules and poorly soluble drugs across epithelial barriers and in bacterial growth inhibition. Ionic liquids are known to denature proteins by the disruption of forces that guide natural protein folding, and the inflammatory enzyme elastase was recently shown to be inhibited by a variety of ionic liquids other than CAGE. Inhibition of collagenolytic enzymes, including elastase, has been shown to improve outcomes in cases of periodontitis via amelioration of periodontal inflammation and alveolar bone resorption. In this study, we investigated whether CAGE prepared with varying stoichiometries was able to inhibit elastase at varying concentrations and whether these CAGE formulations could inhibit the growth of key pathogenic bacterial species associated with oral health conditions. We found that CAGE was capable of inhibiting both porcine elastase and human neutrophil elastase at concentrations as low as 5 mM, and that CAGE formulations were effective at inhibiting the growth of all tested pathogenic oral bacteria. The inhibition of elastase by CAGE may be a mechanism by which CAGE can improve outcomes in periodontitis independent from CAGE's known antibacterial properties.

Chalcone T4 Inhibits RANKL-Induced Osteoclastogenesis and Stimulates Osteogenesis In Vitro

Chalcones are phenolic compounds produced during the biosynthesis of flavonoids that have numerous biological activities, including anti-inflammatory, antioxidant and anticancer. In this in vitro study, we investigate a newly synthesized chalcone (Chalcone T4) in the context of bone turnover, specifically on the modulation of osteoclast differentiation and activity and osteoblast differentiation. Murine macrophages (RAW 264.7) and pre-osteoblasts (MC3T3-E1) were used as models of osteoclasts and osteoblasts, respectively. Differentiation and activity osteoclasts were induced by RANKL in the presence and absence of non-cytotoxic concentrations of Chalcone T4, added in different periods during osteoclastogenesis. Osteoclast differentiation and activity were assessed by actin ring formation and resorption pit assay, respectively. Expression of osteoclast-specific markers (Nfatc1, Oscar, Acp5, Mmp-9 and Ctsk) was determined by RT-qPCR, and the activation status of relevant intracellular signaling pathways (MAPK, AKT and NF-kB) by Western blot. Osteoblast differentiation and activity was induced by osteogenic culture medium in the presence and absence of the same concentrations of Chalcone T4. Outcomes assessed were the formation of mineralization nodules via alizarin red staining and the expression of osteoblast-related genes (Alp e Runx2) by RT-qPCR. Chalcone T4 reduced RANKL-induced osteoclast differentiation and activity, suppressed Oscar, Acp5 and Mmp-9 expression, and decreased ERK and AKT activation in a dose-dependent manner. Nfact1 expression and NF-kB phosphorylation were not modulated by the compound. Mineralized matrix formation and the expression of Alp and Runx2 by MC3T3-E1 cells were markedly stimulated by Chalcone T4. Collectively, these results demonstrate that Chalcone T4 inhibits in osteoclast differentiation and activity and stimulates osteogenesis, which indicates a promising therapeutic potential in osteolytic diseases.

Oral polymicrobial communities: Assembly, function, and impact on diseases

Oral microbial communities assemble into complex spatial structures. The sophisticated physical and chemical signaling systems underlying the community enable their collective functional regulation as well as the ability to adapt by integrating environmental information. The combined output of community action, as shaped by both intra-community interactions and host and environmental variables, dictates homeostatic balance or dysbiotic disease such as periodontitis and dental caries. Oral polymicrobial dysbiosis also exerts systemic effects that adversely affect comorbidities, in part due to ectopic colonization of oral pathobionts in extra-oral tissues. Here, we review new and emerging concepts that explain the collective functional properties of oral polymicrobial communities and how these impact health and disease both locally and systemically.

MicroRNA-126 regulates macrophage polarization to prevent the resorption of alveolar bone in diabetic periodontitis

OBJECTIVE

This study aims to investigate the effects of microRNA-126 (miR-126) on the macrophage polarization in vitro and alveolar bone resorption in vivo.

DESIGN

The relationship between miR-126 and MEK/ERK kinase 2 (MEKK2) was confirmed by dual-luciferase reporter assay. Real-time quantitative polymerase chain reaction, enzyme-linked immunosorbent assay or Western blot was used to detect the changes of miR-126, inducible nitric oxide synthase (iNOS), arginase-1 (Arg-1), tumor necrosis factor (TNF)-α, interleukin (IL)-10, MEKK2 and MEKK2-related pathways: mitogen-activated protein kinase (MAPK) and nuclear factor kappa-B (NF-κB) in RAW264.7 macrophages challenged with Porphyromonas gingivalis (P. gingivalis) lipopolysaccharide (LPS) and/or high glucose and/or miR-126 mimic. In mice with diabetic periodontitis, the expressions of iNOS and Arg-1 in gingiva, and alveolar bone level were detected after miR-126 mimic injection.

RESULTS

MiR-126 could directly bind with MEKK2 3'-untranslated region (UTR). MEKK2, phosphorylation of NF-κB and MAPK signaling proteins, TNF-α and iNOS increased (P < 0.05), while miR-126, Arg-1 and IL-10 were inhibited (P < 0.05) in macrophage challenged with high glucose and/or P. gingivalis LPS, however, miR-126 mimic reversed these effects (P < 0.05). The expressions of iNOS in gingiva and alveolar bone resorption were elevated (P < 0.05), the expression of Arg-1 in gingiva decreased (P < 0.05) in mice with diabetic periodontitis, which could be inhibited by miR-126 mimic.

CONCLUSIONS

miR-126 might prevent alveolar bone resorption in diabetic periodontitis and inhibit macrophage M1 polarization via regulating MEKK2 signaling pathway.

Pre-conditioning of gingival epithelial cells with sub-apoptotic concentrations of curcumin prevents pro-inflammatory cytokine release

BACKGROUND AND OBJECTIVE

Plaque-induced gingival inflammation (gingivitis) is ubiquitous in humans. The epithelial barrier reacts to the presence of oral bacteria and induces inflammatory cascades. The objective of this study was to investigate the mechanism by which the small molecule micronutrient curcumin could decrease inflammatory response in vitro to oral bacterium heat-killed Fusobacterium nucleatum as curcumin could be a useful compound for combatting gingivitis already consumed by humans.

METHODS

H400 oral epithelial cell line was pre-conditioned with curcumin and the production of cytokines was measured by enzyme-linked immunosorbent assay (ELISA) and translocation of transcription factors was used to monitor inflammatory responses. Haem oxygenase (HO-1) expression and molecules that HO-1 releases were evaluated for their potential to reduce the quantity of cytokine production. Immunofluorescence microscopy and Western blotting were used to evaluate changes in transcription factor and enzyme location.

RESULTS

Pre-conditioning of H400 cells with a sub-apoptotic concentration of curcumin (20 μM) attenuated secretion of Granulocyte-Macrophage - Colony-Stimulating Factor (GM-CSF) and reduced NFkB nuclear translocation. This pre-conditioning caused an increase in nuclear Nrf2; an initial drop (at 8 h) followed by an adaptive increase (at 24 h) in glutathione; and an increase in haem oxygenase (HO-1) expression. Inhibition of HO-1 by SnPPIX prevented the curcumin-induced attenuation of GM-CSF production. HO-1 catalyses the breakdown of haem to carbon monoxide, free iron and biliverdin: the HO-1/CO anti-inflammatory pathway. Elevations in carbon monoxide, achieved using carbon monoxide releasing molecule-2 (CORM2) treatment alone abrogated F. nucleatum-induced cytokine production. Biliverdin is converted to bilirubin by biliverdin reductase (BVR). This pleiotropic protein was found to increase in cell membrane expression upon curcumin treatment.

CONCLUSION

Curcumin decreased inflammatory cytokine production induced by Fusobacterium nucleatum in H400 oral epithelial cells. The mechanism of action appears to be driven by the increase of haem oxygenase and the production of carbon monoxide.

Subgingival Microbiota and Periodontal Clinical Status in Patients with Plaque Psoriasis: A Cross-Sectional Study

Plaque Psoriasis (PP) and periodontitis are inflammatory disorders with a bidirectional association. They both have a qualitatively similar immune-modulatory cascade, cytokine profile, and a recently described dysbiosis. Different oral bacterial species compositions in the periodontal pocket might play a role in the development of PP. To describe the subgingival microbiota of the Mexican population with PP and the periodontal conditions. Subjects were divided into two groups: periodontal health (PH) (PH-non-PP, PH-PP) and periodontitis (PD) (P-non-PP, PD-PP). Following clinical examination, the patients were classified into three groups according to the degree of psoriasis as measured by the Psoriasis Area Severity Index (PASI) and the periodontal status according to the parameters of the American Academy of Periodontology (AAP). Subgingival microbiota samples of each patient were used to determine 40 species of periodontal bacteria by checkerboard DNA-DNA hybridization. IL-2 and IL-6 were measured by ELISA. Of the forty-eight patients with PP, 21 patients had PH and 27 patients had PD. PD-PP group has a significant increase in the percentage of plaque, gingival redness, pocket probing depth, and clinical attachment loss (P<0.001) compared to PH-PP group. Microbiologically PD-PP exhibited significantly higher mean counts for A. georgiae, A. israelii, A. naeslundii from blue complex (P<0.001) than PD-non-PP. Moreover, the counts of these Actinomyces in PD-PP increased according to the severity of index PASI. The concentration of IL-2 and IL-6 were increased in saliva from PH-PP and PD-PP patients compared to PH non-PP. PP individuals harbored a particular sub-gingival microbiota profile different from non-PP. The severity of psoriasis was related to dysbiosis of microbiota -PASI > 5 related to periodontitis with the predominance of Actinomyces periodontal, irrespective of their periodontal condition. Finally, the severity of psoriasis could be unbalanced in subgingival microbiota and increase the risk to develop periodontitis.

PD-1/PD-L1 pathway: A double-edged sword in periodontitis

Periodontitis is a disease caused by infection and immunological imbalance, which often leads to the destruction of periodontal tissue. Programmed death protein 1 (PD-1) and its ligand: programmed death ligand 1 (PD-L1) are important "immune checkpoint" proteins that have a negative regulatory effect on T cells and are targets of immunotherapy. Studies have shown that the expression of PD-1 and PD-L1 in patients with periodontitis is higher than that in healthy individuals. The keystone pathogen Porphyromonas gingivalis (P. gingivalis) is believed to be the main factor driving the upregulation of PD-1/PD-L1. High expression of PD-1/PD-L1 can inhibit the inflammatory response and reduce the destruction of periodontal supporting tissues, but conversely, it can promote the "immune escape" of P. gingivalis, thus magnifying infections. In addition, the PD-1/PD-L1 pathway is also associated with various diseases, such as cancer and Alzheimer's disease. In this review, we discuss the influence and mechanism of the PD-1/PD-L1 pathway as a "double-edged sword" affecting the occurrence and development of periodontitis, as well as its function in periodontitis-related systemic disorders. The PD-1/PD-L1 pathway could be a new avenue for periodontal and its related systemic disorders therapy.

Efficacy of a Novel Pleiotropic MMP-Inhibitor, CMC2.24, in a Long-Term Diabetes Rat Model with Severe Hyperglycemia-Induced Oral Bone Loss

Purpose

CMC2.24, a novel 4-(phenylaminocarbonyl)-chemically-modified-curcumin, is a pleiotropic MMP-Inhibitor of various inflammatory/collagenolytic diseases including periodontitis. This compound has demonstrated efficacy in host modulation therapy along with improved resolution of inflammation in various study models. The objective of current study is to determine the efficacy of CMC2.24 in reducing the severity of diabetes, and its long-term role as an MMP-inhibitor, in a rat model.

Methods

Twenty-one adult male Sprague-Dawley rats were randomly distributed into three groups: Normal (N), Diabetic (D) and Diabetic+CMC2.24 (D+2.24). All three groups were orally administered vehicle: carboxymethylcellulose alone (N, D), or CMC2.24 (D+2.24; 30mg/kg/day). Blood was collected at 2-months and 4-months' time-point. At completion, gingival tissue and peritoneal washes were collected/analyzed, and jaws examined for alveolar bone loss by micro-CT. Additionally, sodium hypochlorite(NaClO)-activation of human-recombinant (rh) MMP-9 and its inhibition by treatment with 10μM CMC2.24, Doxycycline, and Curcumin were evaluated.

Results

CMC2.24 significantly reduced the levels of lower-molecular-weight active-MMP-9 in plasma. Similar trend of reduced active-MMP-9 was also observed in cell-free peritoneal and pooled gingival extracts. Thus, treatment substantially decreased conversion of pro- to actively destructive proteinase. Normalization of the pro-inflammatory cytokine (IL-1ß, resolvin-RvD1), and diabetes-induced osteoporosis was observed in presence of CMCM2.24. CMC2.24 also exhibited significant anti-oxidant activity by inhibiting the activation of MMP-9 to a lower-molecular-weight (82kDa) pathologically active form. All these systemic and local effects were observed in the absence of reduction in severity of hyperglycemia.

Conclusion

CMC2.24 reduced activation of pathologic active-MMP-9, normalized diabetic osteoporosis, and promoted resolution of inflammation but had no effect on the hyperglycemia in diabetic rats. This study also highlights the role of MMP-9 as an early/sensitive biomarker in the absence of change in any other biochemical parameter. CMC2.24 also inhibited significant activation of pro-MMP-9 by NaOCl (oxidant) adding to known mechanisms by which this compound treats collagenolytic/inflammatory diseases including periodontitis.

Cinnamaldehyde modulates host immunoinflammatory responses in rat ligature-induced periodontitis and peripheral blood mononuclear cell models

Cinnamaldehyde is a natural product with anti-inflammatory and immune-modulatory properties, known to regulate host responses to bacterial stimuli. This study aimed to investigate the effects of cinnamaldehyde on ligature-induced periodontitis in rats, and its impact on the modulation of human peripheral blood mononuclear cells (PBMC). Male Wistar rats were assigned into three groups:i) control: no ligature + vehicle; ii) ligature: ligature + vehicle; and iii) ligature + cinnamaldehyde (50 mg/kg); all treatments by daily oral gavage. After 14 days of induced periodontitis, the hemimandibles were collected for bone loss evaluation. The gingival levels of IL-1β, MMP-9 and iNOS mRNA were evaluated. Nitric oxide (NO) was measured in both rat saliva and plasma. PBMC were stimulated with Aggregatibacter actinomycetemcomitans (Aa) in the presence or absence of cinnamaldehyde (5, 20 e 40 µM), and cytokine production was quantified in cell supernatant. Proliferating lymphocytes were taken for flow cytometer reading, while culture supernatants were used for IFN-γ and IL-10 assessment. The ligature group had both increased alveolar bone loss and gingival expression of IL-1β, MMP-9 and iNOS compared to the control group. All parameters were attenuated by cinnamaldehyde treatment. Lower salivary but not plasma NO was detected in the cinnamaldehyde compared to the ligature group. Aa-stimulated PBMCs treated with cinnamaldehyde produced less IL-1β; the compound also attenuated lymphocyte proliferation in a dose-dependent manner, as well as cell IL-10 production. Cinnamaldehyde treatment reduced periodontal bone loss, and downregulated key inflammatory mediators and human PBMC responses, pointing to novel potential therapeutic effects of this compound.

The Antimicrobial Activity of Curcumin and Xanthohumol on Bacterial Biofilms Developed over Dental Implant Surfaces

In search for natural products with antimicrobial properties for use in the prevention and treatment of peri-implantitis, the purpose of this investigation was to evaluate the antimicrobial activity of curcumin and xanthohumol, using an in vitro multi-species dynamic biofilm model including Streptococcus oralis, Actinomyces naeslundii, Veillonella parvula, Fusobacterium nucleatum, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. The antimicrobial activities of curcumin (5 mM) and xanthohumol (100 μM) extracts, and the respective controls, were evaluated with 72-h biofilms formed over dental implants by their submersion for 60 seconds. The evaluation was assessed by quantitative polymerase chain reaction (qPCR), confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). For the data analysis, comparisons were tested applying ANOVA tests with post-hoc Bonferroni corrections to evaluate the antimicrobial activity of both extracts. With qPCR, statistically significant reductions in bacterial counts were observed for curcumin and xanthohumol, when compared to the negative control. The results with CLSM and SEM were consistent with those reported with qPCR. It was concluded that both curcumin and xanthohumol have demonstrated antimicrobial activity against the six bacterial species included in the dynamic in vitro biofilm model used.

The Oral Microbiota in Valvular Heart Disease: Current Knowledge and Future Directions

Oral microbiota formation begins from birth, and everything from genetic components to the environment, alongside the host's behavior (such as diet, smoking, oral hygiene, and even physical activity), contributes to oral microbiota structure. Even though recent studies have focused on the gut microbiota's role in systemic diseases, the oral microbiome represents the second largest community of microorganisms, making it a new promising therapeutic target. Periodontitis and dental caries are considered the two main consequences of oral bacterial imbalance. Studies have shown that oral dysbiosis effects are not limited locally. Due to technological advancement, research identified oral bacterial species in heart valves. This evidence links oral dysbiosis with the development of valvular heart disease (VHD). This review focuses on describing the mechanism behind prolonged local inflammation and dysbiosis, that can induce bacteriemia by direct or immune-mediated mechanisms and finally VHD. Additionally, we highlight emerging therapies based on controlling oral dysbiosis, periodontal disease, and inflammation with immunological and systemic effects, that exert beneficial effects in VHD management.

Revisiting Periodontal Disease in Dogs: How to Manage This New Old Problem?

Periodontal disease (PD) is one of the most prevalent oral inflammatory diseases in dogs. PD onset begins with the formation of a polymicrobial biofilm (dental plaque) on the surface of the teeth, followed by a local host inflammatory response. To manage this disease, several procedures focusing on the prevention and control of dental plaque establishment, as well as on the prevention of local and systemic PD-related consequences, are essential. The removal of dental plaque and the inhibition of its formation can be achieved by a combination of dental hygiene homecare procedures including tooth brushing, the application of different oral products and the use of specific diet and chew toys, and regular professional periodontal procedures. Additionally, in some cases, periodontal surgery may be required to reduce PD progression. Associated with these measures, host modulation therapy, antimicrobial therapy, and other innovative therapeutic options may be useful in PD management. Moreover, PD high prevalence and its relation with potential local and systemic consequences reinforce the need for investment in the development of new preventive measures, treatments, and oral procedures to improve the control of this disease in dogs. Knowledge on the specific guidelines and diversity of the available products and procedures are fundamental to apply the most adequate treatment to each dog with PD.

Beneficial Effects of Melatonin on Periodontitis Management: Far More Than Oral Cavity

Periodontitis as a highly prevalent chronic infection/inflammatory disease can eventually lead to tooth loss and masticatory dysfunction. It also has a negative impact on general health and largely impairs quality of life. The tissue destruction during periodontitis is mainly caused by the excessive immune-inflammatory response; hence, how to modulate the host's reaction is of profound importance for effective periodontal treatment and tissue protection. Melatonin, as an endogenous hormone exhibiting multiple biological functions such as circadian rhythm regulation, antioxidant, and anti-inflammation, has been widely used in general healthcare. Notably, the past few years have witnessed increasing evidence for the application of melatonin as an adjunctive approach in the treatment of periodontitis and periodontitis-related systemic comorbidities. The detailed underlying mechanisms and more verification from clinical practice are still lacking, however, and further investigations are highly required. Importantly, it is essential to establish standard guidelines in the near future for the clinical administration of melatonin for periodontal health and general wellbeing.

Advances in novel therapeutic approaches for periodontal diseases

Periodontal diseases are pathological processes resulting from infections and inflammation affecting the periodontium or the tissue surrounding and supporting the teeth. Pathogenic bacteria living in complex biofilms initiate and perpetuate this disease in susceptible hosts. In some cases, broad-spectrum antibiotic therapy has been a treatment of choice to control bacterial infection. However, increasing antibiotic resistance among periodontal pathogens has become a significant challenge when treating periodontal diseases. Thanks to the improved understanding of the pathogenesis of periodontal disease, which involves the host immune response, and the importance of the human microbiome, the primary goal of periodontal therapy has shifted, in recent years, to the restoration of homeostasis in oral microbiota and its harmonious balance with the host periodontal tissues. This shift in therapeutic goals and the drug resistance challenge call for alternative approaches to antibiotic therapy that indiscriminately eliminate harmful or beneficial bacteria. In this review, we summarize the recent advancement of alternative methods and new compounds that offer promising potential for the treatment and prevention of periodontal disease. Agents that target biofilm formation, bacterial quorum-sensing systems and other virulence factors have been reviewed. New and exciting microbiome approaches, such as oral microbiota replacement therapy and probiotic therapy for periodontal disease, are also discussed.

Therapeutic and Metagenomic Potential of the Biomolecular Therapies against Periodontitis and the Oral Microbiome: Current Evidence and Future Perspectives

The principles of periodontal therapy are based on the control of microbial pathogens and host factors that contribute to biofilm dysbiosis, with the aim of modulating the progression of periodontitis and periodontal tissue destruction. It is currently known how differently each individual responds to periodontal treatment, depending on both the bacterial subtypes that make up the dysbiotic biofilm and interindividual variations in the host inflammatory response. This has allowed the current variety of approaches for the management of periodontitis to be updated by defining the goals of target strategies, which consist of reducing the periodontopathogenic microbial flora and/or modulating the host-mediated response. Therefore, this review aims to update the current variety of approaches for the management of periodontitis based on recent target therapies. Recently, encouraging results have been obtained from several studies exploring the effects of some targeted therapies in the medium- and long-term. Among the most promising target therapies analyzed and explored in this review include: cell-based periodontal regeneration, mediators against bone resorption, emdogain (EMD), platelet-rich plasma, and growth factors. The reviewed evidence supports the hypothesis that the therapeutic combination of epigenetic modifications of periodontal tissues, interacting with the dysbiotic biofilm, is a key step in significantly reducing the development and progression of disease in periodontal patients and improving the therapeutic response of periodontal patients. However, although studies indicate promising results, these need to be further expanded and studied to truly realize the benefits that targeted therapies could bring in the treatment of periodontitis.

Ultra-small molybdenum-based nanodots as an antioxidant platform for effective treatment of periodontal disease

Periodontal disease (PD) is a local inflammatory disease with high morbidity, manifesting tissue destruction results from inflammation of the host immune response to bacterial antigens and irritants. The supportive function of connective tissue and skeletal tissue can be jeopardized without prompt and effective intervention, representing the major cause of tooth loss. However, traditional treatments exhibited great limitations, such as low efficacies, causing serious side effects and recurrent inflammatory episodes. As a major defense mechanism, reactive oxygen species (ROS) play important roles in the pathological progression of PD. Antioxidant therapy is widely believed to be an effective strategy for ROS-triggered diseases, including oxidative stress-induced PD. Most antioxidants can only scavenge one or a few limited kinds of ROS and cannot handle all kinds. In addition, current antioxidant nanomaterials present limitations associated with toxicity, low stability, and poor biocompatibility. To this end, we develop ultra-small molybdenum-based nanodots (MoNDs) with strong ROS in oxidative stress-induced PD. To the best of our knowledge, this is the first time that MoNDs have been used for PD. In the present study, MoNDs have shown extremely good therapeutic effects as ROS scavengers. Spectroscopic and in vitro experiments provided strong evidence for the roles of MoNDs in eliminating multiple ROS and inhibiting ROS-induced inflammatory responses. In addition, the mouse model of PD was established and demonstrated the feasibility of MoNDs as powerful antioxidants. It can alleviate periodontal inflammation by scavenging multiple ROS without obvious side effects and exhibit good biocompatibility. Thus, this newly developed nanomedicine is effective in scavenging ROS and inhibiting M1 phenotypic polarization, which provides promising candidates for the treatment of PD.

Investigation of the impact of rosuvastatin and telmisartan in doxorubicin-induced acute cardiotoxicity

Cardiac injury is the main dose-limiting factor for doxorubicin (Dox) use as an anticancer agent. The cardiotoxicity of Dox is linked to a number of complex mechanisms, including oxidative stress, mitochondrial damage, intracellular calcium dysregulation, and apoptosis/necrosis. This study investigates several aspects of Dox-induced cardiotoxicity. We investigated the effects of pre-treatment with rosuvastatin and telmisartan, which were used in different doses alone or combination, on the acute cardiotoxicity induced by Dox. The results of this study showed that Dox induced significant pathological changes in the cardiomyocytes. Adverse effects were observed on several biomarkers related to cardiac damage like cardiac troponin I (cTnI) and lactate dehydrogenase (LDH), oxidative stress like malondialdehyde (MDA), an inflammatory process like interleukin-17 (IL-17) with important histopathological changes. We illusterate the cardio-protective contribution of the two pharmacological agents against the acute cardiotoxic effects of Dox. This is manifested by the significant improvement in the biomarker levels and the associated histological damage. This study points out the beneficial use of both rosuvastatin and telmisartan alone or in combination as a clinical option for decreasing the acute toxicity of Dox on cardiomyocytes.

Identification of Key Gene Targets for Periodontitis Treatment by Bioinformatics Analysis

Background. Periodontitis is considered to be the leading cause of tooth loss in adults, and it interacts with some serious systemic diseases. Periodontal basic therapy is the cornerstone of periodontal disease treatment and long-term maintenance and has a positive impact on the treatment of systemic diseases. Aim. To explore the potential gene targets of periodontitis therapies by bioinformatics method. Methods. We analyzed the expression database (GSE6751) downloaded from the Gene Expression Omnibus (GEO) with weighted gene coexpression network analysis (WGCNA) to confirm the functional gene modules. Pathway enrichment network analyses the key genes in functional modules and verified the candidate genes from the samples in peripheral blood sources of GSE43525. Moreover, we confirmed the expression of target protein in the periodontal tissues of experimental periodontitis-afflicted mice using western blotting. Results. The functional gene modules were found to have biological processes, and ARRB2, BIRC3, CD14, DYNLL1, FCER1G, FCGR1A, FCGR2B, FGR, HCK, and PRKCD were screened as candidates’ genes in functional modules. The 921 DEG from GSE43525 and 418 DEG is from the green module of GSE6751 and identified AMICA1, KDELR1, DHRS7B, LMNB1, CTSA, S100A12, and FCGR1A as target genes. Finally, FCGR1A (CD64) was confirmed as the key gene that affects periodontal treatment. Western blot analysis showed an increasing trend in the expression level of FCGR1A protein in the periodontal tissues of experimental periodontitis mice compared to normal mice. Conclusions. FCGR1A (CD64) may be a key gene target for periodontal therapy in patients with periodontitis and other systemic diseases.

Host Response Modulation Therapy in the Diabetes Mellitus—Periodontitis Conjuncture: A Narrative Review

The inflammatory response of the host in periodontitis is the phenomenon that underlies the onset and evolution of periodontal destructive phenomena. A number of systemic factors, such as diabetes mellitus (DM), can negatively affect the patient with periodontitis, just as the periodontal disease can aggravate the status of the DM patient. Host response modulation therapy involves the use of anti-inflammatory and anti-oxidant products aimed at resolving inflammation, stopping destructive processes, and promoting periodontal healing, all important aspects in patients with high tissue loss rates, such as diabetic patients. This paper reviews the data available in the literature on the relationship between DM and periodontitis, the main substances modulating the inflammatory response (nonsteroidal anti-inflammatory drugs, sub-antimicrobial doses of doxycycline, or omega-3 fatty acids and their products, specialized pro-resolving mediators), as well as their application in diabetic patients.

The Effects of 810 nm Diode Laser and Indocyanine Green on Periodontal Parameters and HbA1c in Patients with Periodontitis and Type II Diabetes Mellitus: A Randomized Controlled Study

The aim of this study was to investigate the effects of adjunctive periodontal therapy of 5 mg/mL indocyanine green irradiation by an 810 nm diode laser (aPDT), supplementary to scaling and root planing (SRP) in patients with periodontitis and type II diabetes mellitus (DM) compared to the SRP alone, on periodontal clinical parameters and glycated hemoglobin A1c (HbA1c). The study was conducted on 49 subjects with type II DM and periodontitis, divided into two groups: the SRP group (n = 25), who followed SRP alone, and the SRP + aPDT group (n = 24), who followed SRP and four weekly sessions of indocyanine green irradiation by an 810 nm diode laser. Plaque Index (PI), Bleeding on Probing Index (BOP), probing depth (PD), clinical attachment loss (CAL) and HbA1c were investigated at baseline and after 6 months. At 6 months, both SRP alone and SRP + aPDT generated significant reductions in all the investigated parameters; SRP + aPDT produced more significant reductions for BOP, PD and CAL (p < 0.001) but not for PI and HbA1c, than SRP alone. aPDT with indocyanine green therapy was well tolerated, with two subjects reporting slight discomfort. Therefore, aPDT with indocyanine green might represent a good adjunctive periodontal treatment option for SRP in patients with type II DM and periodontitis.