Determination of the antibacterial activity of simvastatin against periodontal pathogens, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans: An in vitro study

Bacteraemia and proinflammatory response after non-surgical periodontal therapy and adjunctive antibiotics in patients with recent acute coronary syndrome

INTRODUCTION

This study compares the incidence of bacteraemia and proinflammatory cytokines in short and long periods after non-surgical periodontal therapy involving premedication with amoxicillin (AMX) followed by AMX and metronidazole (MTZ) in patients with Acute Coronary Syndrome (ACS).

METHODS

This pilot study included twelve individuals with periodontitis and recent ACS. Six patients were treated with subgingival instrumentation (SI), and six with supragingival ultrasonic scaling (US). Amoxicillin 2 g was administered as premedication in the first visit, followed by AMX-MTZ for one week. The incidence of bacteraemia was evaluated using hemoculture, qPCR, and next-generation sequencing (NGS) before the treatment (t0) and 30 min later (t1) (quadrants 1 and 2), and after one-week, pre-post-treatment samples were taken from the re-maining quadrants (t3 and t4). Proinflammatory cytokines were evaluated in serum at baseline (t0), one week (t1), and six months (t5).

RESULTS

Bacteraemia was low in 16.6 %, similar in both treatment groups. Porphyromonas gingivalis and Desulfobulbus oralis (16.6 %), Filifactor alocis, Eubacterium saphenum, Eubacterium brachy (8.3 %) were identified with qPCR. NGS was only detected in a single patient; at time t0, bacteria were more diverse than at t3 and were associated with the phyla Bacteroidetes and Proteobacteria. Interestingly, many clones observed in blood were non-oral. After treatment, all cytokines were reduced significantly in the SI group in the long term (p< 0.05).

CONCLUSIONS

Periodontal therapy reduced bacteremia: despite the antibiotic regimen, bacteria remained in peripheral blood, which could be associated with antimicrobial resistance. SI produced a more efficient reduction of proinflammatory cytokines after periodontal treatment in individuals with ACS.

Statins, Allies against Antibiotic Resistance?

Due to the ever-increasing rate of antibacterial resistance, the search for effective antibacterial agents has become imperative. Researchers have investigated the potential antimicrobial properties of various classes of nonantibiotic drugs. Statins are a group of antihyperlipidemic drugs with several cholesterol-independent effects, including antiinflammatory, immune-modulating, antioxidant, and antibacterial effects. In vitro and in vivo studies have demonstrated the antibacterial properties of statins against various grampositive and gram-negative bacteria. Simvastatin and atorvastatin are the most potent members of the family. Their antibacterial effect can be attributed to several direct and indirect mechanisms. Bacterial invasion, growth, and virulence are affected by statins. However, since in vitro minimum inhibitory concentrations (MICs) are significantly higher than serum concentrations at the lipid-lowering dosage, indirect mechanisms have been suggested to explain the positive clinical results, including reducing inflammation and improving immune response capacity. Further, statins have shown promising results when combined with antibiotics and other antibacterial agents, such as triazenes and silver nanoparticles. Despite this, the controversial aspects of statins have cast doubt on their efficacy as a possible solution for antibacterial resistance, and further research is required. Consequently, this review will examine in detail the current clinical and in vitro findings and controversies regarding statins' antibacterial properties and their relevance to antibacterial resistance.

Biosynthesis and Characterization of Silver Nanoparticles and Simvastatin Association in Titanium Biofilms

INTRODUCTION

Simvastatin is an antilipidemic drug that has already demonstrated antibacterial activities on oral and non-oral microorganisms. Silver nanoparticles also exhibit antimicrobial properties, particularly for coating implant surfaces. In this study, we evaluated the effects of combining simvastatin with silver nanoparticles on the formation and viability of biofilms consolidated on titanium discs.

METHODS

Silver nanoparticles were first biosynthesized using the fungus Fusarium oxysporum and then characterized using Dynamic Light Scattering, X-ray Diffraction, Transmission Electron Microscopy, and energy dispersive spectroscopy. Species of Streptococcus oralis, Streptococcus mutans, Porphyromonas gingivalis, Methicillin-sensitive Staphylococcus aureus, and Methicillin-resistant Staphylococcus aureus were used and tested using Minimum Inhibitory Concentration assays with concentrations of silver nanoparticles and simvastatin alone and in combination. Biofilm inhibition and viability tests were performed on titanium surfaces. Toxicity tests were also performed on Galleria mellonella moth larvae.

RESULTS

The silver nanoparticles had a spherical shape without the formation of aggregates as confirmed by Transmission Electron Microscopy. Dynamic Light Scattering revealed nanoparticles with an average diameter of 53.8 nm (±1.23 nm), a polydispersity index of 0.23 and a zeta potential of -25 mV (±2.19 mV). The silver nanoparticles inhibited the growth of the strains tested in the range of 0.001592 and 63.75, while simvastatin alone inhibited the growth of the same strains in the range of 3.125-62.5 µg/mL. The antibacterial activity test of the combination of the two substances showed a reduction in the Minimum Inhibitory Concentration of about two to eight times, showing synergistic effects on Staphylococcus aureus and additive effects on Streptococcus oralis and Porphyromonas gingivalis. As for biofilm, sub-inhibitory concentrations of the combination of substances showed better antibacterial activity in inhibiting the formation of Streptococcus oralis biofilm, and this combination also proved effective in eradicating already established biofilms compared to the substances alone. The combination of silver nanoparticles and simvastatin showed low toxicity to Galleria mellonella moth larvae.

CONCLUSIONS

The results presented indicate that the combination of the two substances could be an alternative for the prevention and reduction of biofilms on implants. These findings open up new possibilities in the search for alternatives for the treatment of peri-implant infections, as well as the possibility of using lower doses compared to single drugs, achieving the same results and reducing potential toxic effects.

Effect of atorvastatin gel in non-surgical treatment of peri-implant mucositis: A randomized controlled clinical trial

Background

Peri-implant diseases, such as peri-implant mucositis and peri-implantitis, are inflammatory conditions caused by biofilms that can lead to the loss of surrounding soft tissues and bone. The most effective treatment involves non-surgical mechanical debridement to remove plaque, but other treatment modalities have shown limited success. This study investigated the anti-inflammatory and immunomodulatory effects of atorvastatin (ATV) gel as an additional treatment for peri-implant mucositis.

Methods

In this double-masked, randomized clinical trial, 49 patients with peri-implant mucositis were randomly divided into two treatment groups: mechanical debridement (MD)+placebo or MD+ATV gel. At baseline, 1 month, and 3 months after the intervention, periodontal parameters, including probing depth (PD), bleeding on probing (BOP), clinical attachment level (CAL), and pain on probing (POP), were measured. Data were analyzed using independent t-test and paired t-test.

Results

Statistically significant improvements in CAL and POP were observed from baseline to each time point throughout the study period (P≤0.001). PD and BOP were statistically significant 1 month and 3 months after the intervention, respectively (P<0.05).

Conclusion

The clinical parameters associated with peri-implant mucosal inflammation further improved when ATV gel was used with MD.

Unravelling the intricacies of Porphyromonas gingivalis: virulence factors, lifecycle dynamics and phytochemical interventions for periodontal disease management

Porphyromonas gingivalis is a gram-negative anaerobic bacterium recognized for its pivotal role in the pathogenesis of periodontal diseases. This review covers an overview of the virulence factors and lifecycle stages of P. gingivalis, with a specific focus on attachment and colonization, biofilm formation, growth and multiplication, dormancy survival and dissemination. Additionally, we explore the significance of inter-bacterial cross-feeding within biofilms. Furthermore, we discuss potential phytochemical-based strategies to target P. gingivalis, including the use of curcumin, apigenin, quercetin and resveratrol. Understanding the virulence factors and lifecycle stages of P. gingivalis, along with the promising phytochemical-based interventions, holds promise for advancing strategies in periodontal disease management and oral health promotion.

Simvastatin, Its Antimicrobial Activity and Its Prevention of Alzheimer's Disease

Simvastatin, a blockbuster drug for treating hypercholesterolemia, has multifactorial benefits as an antimicrobial agent and plays a preventative role in reducing the incidence of Alzheimer's Disease (AD). Although most of the beneficial effects of simvastatin have been attributed to its ability to reduce cholesterol levels, recent scientific studies have suggested that its benefits are largely due to its pleiotropic effects in targeting other pathways, e.g., by inhibiting protein lipidation. There are certain pleiotropic effects that can be predicted from the inhibition of the mevalonate pathway; however, some of the effects of simvastatin in proteostasis lead to reduced levels of amyloid beta, the key contributor to AD. This review discusses the use of simvastatin as an antimicrobial agent and anti-AD drug.

Cystatin C: immunoregulation role in macrophages infected with Porphyromonas gingivalis

Background

Periodontitis is a chronic infectious disease, characterized by an exacerbated inflammatory response and a progressive loss of the supporting tissues of the teeth. Porphyromonas gingivalis is a key etiologic agent in periodontitis. Cystatin C is an antimicrobial salivary peptide that inhibits the growth of P. gingivalis. This study aimed to evaluate the antimicrobial activity of this peptide and its effect on cytokine production, nitric oxide (NO) release, reactive oxygen species (ROS) production, and programmed cell death in human macrophages infected with P. gingivalis.

Methods

Monocyte-derived macrophages generated from peripheral blood were infected with P. gingivalis (MOI 1:10) and stimulated with cystatin C (2.75 µg/ml) for 24 h. The intracellular localization of P. gingivalis and cystatin C was determined by immunofluorescence and transmission electron microscopy (TEM). The intracellular antimicrobial activity of cystatin C in macrophages was assessed by counting Colony Forming Units (CFU). ELISA assay was performed to assess inflammatory (TNFα, IL-1β) and anti-inflammatory (IL-10) cytokines. The production of nitrites and ROS was analyzed by Griess reaction and incubation with 2',7'-dichlorodihydrofluorescein diacetate (H2DCFDA), respectively. Programmed cell death was assessed with the TUNEL assay, Annexin-V, and caspase activity was also determined.

Results

Our results showed that cystatin C inhibits the extracellular growth of P. gingivalis. In addition, this peptide is internalized in the infected macrophage, decreases the intracellular bacterial load, and reduces the production of inflammatory cytokines and NO. Interestingly, peptide treatment increased ROS production and substantially decreased bacterial-induced macrophage apoptosis.

Conclusions

Cystatin C has antimicrobial and immuno-regulatory activity in macrophages infected with P. gingivalis. These findings highlight the importance of understanding the properties of cystatin C for its possible therapeutic use against oral infections such as periodontitis.

The Development of Thermoresponsive Polymeric Simvastatin Prodrug for the Treatment of Experimental Periodontitis in Rats

Periodontitis (PD) is a severe inflammatory gum pathology that damages the periodontal soft tissue and bone. It is highly prevalent in the US, affecting more than 47% of adults. Besides routine scaling and root planing, there are few effective treatments for PD. Developed as an effective treatment for hyperlipidemia, simvastatin (SIM) is also known for its well-established anti-inflammatory and osteogenic properties, suggesting its potential utility in treating PD. Its clinical translation, however, has been impeded by its poor water-solubility, lack of osteotropicity, and side effects (e.g., hepatoxicity) associated with systemic exposure. To address these challenges, an N-(2-hydroxypropyl) methacrylamide (HPMA) copolymer-based thermoresponsive polymeric prodrug of SIM (ProGel-SIM) was developed as a local therapy for PD. Its aqueous solution is free-flowing at 4 °C and transitions into a hydrogel at ∼30 °C, allowing for easy local application and retention. After a thorough characterization of its physicochemical properties, ProGel-SIM was administered weekly into the periodontal pocket of an experimental rat model of PD. At 3 weeks post initiation of the treatment, the animals were euthanized with palate isolated for μ-CT and histological analyses. When compared to dose equivalent simvastatin acid (SMA, active form of SIM) treatment, the rats in the ProGel-SIM treated group showed significantly higher periodontal bone volume (0.34 mm3 vs 0.20 mm3, P = 0.0161) and less neutrophil (PMN) infiltration (P < 0.0001) and IL-1β secretion (P = 0.0036). No measurable side effect was observed. Collectively, these results suggest that ProGel-SIM may be developed as a promising drug candidate for the effective clinical treatment of PD.

Comparative Evaluation of Tetracycline Hydrochloride Fiber and Simvastatin Gel as an Adjunct to Scaling and Root Planing in Periodontitis Patients

Inflammation of oral soft tissues, caused by periodontal disease, results in the loss of attachment to supporting therapy and is a severe threat to dental health. Although there are a number of therapeutic options available, mechanical debridement continues to be the gold standard. Scaling and root planing is the gold standard therapy for periodontitis, but this research aims to examine the efficacy of tetracycline fibers and simvastatin gel as local drug delivery methods. We evaluated 60 sites, splitting them into three groups: 20 sites received just scaling and root planing; 20 sites received scaling and root planing plus simvastatin gel; and 20 sites received scaling and root planing plus tetracycline fibers. Clinical indicators such as the gingival index, the modified sulcular bleeding index, and the probing depth were measured at the start of the study, after one week, after one month, after three months, and after six months. After six months, the simvastatin group reduced the gingival index and modified sulcular bleeding index more than the tetracycline group, whereas the tetracycline group reduced probing depth more than the simvastatin group.

Effects of metformin on human gingival fibroblasts: an in vitro study

OBJECTIVE

To investigate the effects of metformin (MF) treatment on the matrix metalloproteinases (MMPs) and proinflammatory cytokines production from lipopolysaccharide (LPS) - stimulated human gingival fibroblasts (HGFs).

METHODS

HGFs were obtained from subcultures of biopsies from clinically healthy gingival tissues of patients undergoing oral surgeries. Cell cytotoxicity assay was used to determine the effect of different concentrations of MF on viability of HGFs. HGFs were then incubated and treated with different concentrations of MF and Porphyromonas gingivais (Pg) LPS. MMP-1, MMP-2, MMP-8, MMP-9, IL-1β, and IL-8 expression analysis was performed using xMAP technology (Luminex 200, Luminex, Austin, TX, USA). Student's t-test for a single sample was used to compare the mean values of the study groups with the control value. A p-value of <0.05 and 95% confidence intervals were used to report the statistical significance and precision of mean values.

RESULTS

Concentrations of 0.5, 1- and 2-mM MF had a minimal non-significant cytotoxic effect on the HGFs and caused statistically significant reduction of MMP-1, MMP-2, MMP-8 and IL-8 expressed by the LPS-stimulated HGFs.

CONCLUSION

The results of the present study confirm that MF suppresses MMP-1, MMP-2, MMP-8 and IL-8 in LPS-stimulated HGFs suggesting an anti-inflammatory effect of MF and potential adjunct therapeutic role in the treatment of periodontal diseases.

Antimicrobial and anti-inflammatory activity of Cystatin C on human gingival fibroblast incubated with Porphyromonas gingivalis

Background

Periodontal disease is considered one of the most prevalent chronic infectious diseases, often leading to the disruption of tooth-supporting tissues, including alveolar bone, causing tooth mobility and loss. Porphyromonas gingivalis is considered the major etiological agent of this disease, having a plethora of virulence factors, including, lipopolysaccharides (LPS), hemolysins, and proteinases. Antimicrobial peptides are one of the main components of the innate immune response that inhibit the growth of P. gingivalis. The aim of this study was to analyze the antimicrobial activity of cystatin C and to assess the effect on the inflammatory and anti-inflammatory cytokines, the production of reactive oxygen species, and in the release of nitric oxide by human gingival fibroblasts incubated with P. gingivalis in the presence and absence of cystatin C.

Methods

P. gingivalis ATCC 33277 was exposed to cystatin C for 24h and co-cultured with human gingival fibroblasts (HGFs) ATCC CRL-2014. The effect of cystatin on growth of P. gingivalis and HGFs was evaluated. Pro-inflammatory (TNFα, IL-1β) and anti-inflammatory (IL-10) cytokines were determined by ELISA in the supernatants of HGFs incubated with P. gingivalis exposed to cystatin C. Additionally, nitrites and reactive oxygen species (ROS) production were evaluated.

Results

Cystatin Cinhibited the growth of P. gingivalis without affecting HGFs. Incubation of HGFs with P. gingivalis led to a significant increase of TNF-α and IL-1β. In contrast, HGFs incubated with P. gingivalis exposed to cystatin C showed a decreased production of both cytokines, whereas IL-10 was enhanced. Incubation of HGFs with P. gingivalis led to an increase of nitric oxide (NO) and ROS production, which was reduced in the presence of the peptide.

Conclusions

Cystatin C inhibits the growth of P. gingivalis and decreases the inflammatory cytokines, ROS, and NO production during infection of HGFs with P. gingivalis. Knowledge on the antimicrobial and immunomodulatory properties of cystatin C could aid in the design of new therapeutic approaches to facilitate the elimination of this bacterium to improve the treatment of periodontal disease.

Periodontal therapy for primary or secondary prevention of cardiovascular disease in people with periodontitis

BACKGROUND

There may be an association between periodontitis and cardiovascular disease (CVD); however, the evidence so far has been uncertain about whether periodontal therapy can help prevent CVD in people diagnosed with chronic periodontitis. This is the third update of a review originally published in 2014, and most recently updated in 2019. Although there is a new multidimensional staging and grading system for periodontitis, we have retained the label 'chronic periodontitis' in this version of the review since available studies are based on the previous classification system.

OBJECTIVES

To investigate the effects of periodontal therapy for primary or secondary prevention of CVD in people with chronic periodontitis.

SEARCH METHODS

An information specialist searched five bibliographic databases up to 17 November 2021 and additional search methods were used to identify published, unpublished, and ongoing studies. We also searched the Chinese BioMedical Literature Database, the China National Knowledge Infrastructure, the VIP database, and Sciencepaper Online to March 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared active periodontal therapy to no periodontal treatment or a different periodontal treatment. We included studies of participants with a diagnosis of chronic periodontitis, either with CVD (secondary prevention studies) or without CVD (primary prevention studies).

DATA COLLECTION AND ANALYSIS

Two review authors carried out the study identification, data extraction, and 'Risk of bias' assessment independently and in duplicate. They resolved any discrepancies by discussion, or with a third review author. We adopted a formal pilot-tested data extraction form, and used the Cochrane tool to assess the risk of bias in the studies. We used GRADE criteria to assess the certainty of the evidence.

MAIN RESULTS

There are no new completed RCTs on this topic since we published our last update in 2019. We included two RCTs in the review. One study focused on the primary prevention of CVD, and the other addressed secondary prevention. We evaluated both as being at high risk of bias. Our primary outcomes of interest were death (all-cause and CVD-related) and all cardiovascular events, measured at one-year follow-up or longer. For primary prevention of CVD in participants with periodontitis and metabolic syndrome, one study (165 participants) provided very low-certainty evidence. There was only one death in the study; we were unable to determine whether scaling and root planning plus amoxicillin and metronidazole could reduce incidence of all-cause death (Peto odds ratio (OR) 7.48, 95% confidence interval (CI) 0.15 to 376.98), or all CVD-related death (Peto OR 7.48, 95% CI 0.15 to 376.98). We could not exclude the possibility that scaling and root planning plus amoxicillin and metronidazole could increase cardiovascular events (Peto OR 7.77, 95% CI 1.07 to 56.1) compared with supragingival scaling measured at 12-month follow-up. For secondary prevention of CVD, one pilot study randomised 303 participants to receive scaling and root planning plus oral hygiene instruction (periodontal treatment) or oral hygiene instruction plus a copy of radiographs and recommendation to follow-up with a dentist (community care). As cardiovascular events had been measured for different time periods of between 6 and 25 months, and only 37 participants were available with at least one-year follow-up, we did not consider the data to be sufficiently robust for inclusion in this review. The study did not evaluate all-cause death and all CVD-related death. We are unable to draw any conclusions about the effects of periodontal therapy on secondary prevention of CVD.

AUTHORS' CONCLUSIONS

For primary prevention of cardiovascular disease (CVD) in people diagnosed with periodontitis and metabolic syndrome, very low-certainty evidence was inconclusive about the effects of scaling and root planning plus antibiotics compared to supragingival scaling. There is no reliable evidence available regarding secondary prevention of CVD in people diagnosed with chronic periodontitis and CVD. Further trials are needed to reach conclusions about whether treatment for periodontal disease can help prevent occurrence or recurrence of CVD.

Biosynthesis of Silver Nanoparticles Using Bersama engleriana Fruits Extracts and Their Potential Inhibitory Effect on Resistant Bacteria

The absence of novel, safe, and effective bactericide is an urgent concern worldwide and remains a challenge in scientific communities. The unique proprieties of silver nanoparticles (SNPs) synthesized from plant extracts make them a suitable candidate to overcome these limitations. Herein, we synthesized SNPs from Bersama engleriana fruit (BEfr) extracts and determined their potential antibacterial activity and mode of action. SNPs were synthesized from BEfr methanolic fruit extracts at 25 and 70 °C, and the antibacterial effectiveness of SNPs against bacterial strains was investigated. The surface plasmon resonance peaked at 430.18 and 434.08 nm, respectively, for SNPs synthesized at 25 and 70 °C, confirming SNPs synthesis. BEfr-SNPs had minimum inhibitory concentrations (MIC) range of 0.234 to >50 µg/mL, which was 30-fold greater than extract alone (MIC of 500 µg/mL). BEfr-SNPs-25 °C was potent against six bacterial strains (S. aureus, S. enterica, MRS. aureus, K. pneumonia, and S. pyogenes), with MIC range of 0.339 to 6.25 µg/mL. The mode of action of BEfr-SNPs-25 °C was achieved by an MRSA bacteria strain outer membrane and DNA nucleotide linkage. These results suggest that our synthesized SNPs, especially BEfr-SNPs-25 °C, demonstrated an enhanced antibacterial effect and could be potential candidates for bacterial infection treatment.

Effect of three intracanal medicaments used in pulp regeneration on the push-out bond strength of mineral trioxide aggregate and calcium-enriched mixture: An in vitro study

Background. The bond strength of the materials used as a cervical barrier in the pulp regeneration is essential for the success of treatment. This study aimed to evaluate the effects of triple antibiotic paste (TAP), double antibiotic paste (DAP), and simvastatin as intracanal medicaments on the dislodgement resistance of mineral trioxide aggregate (MTA) and calcium-enriched mixture (CEM). Methods. A total of 160 extracted human single-rooted teeth were selected, and root canal preparation was carried out. The teeth in each group were randomly divided into four subgroups: TAP, DAP, simvastatin, and the control group (without intracanal medicament). Four weeks after placing the medicaments, it was removed by sodium hypochlorite, and MTA and CEM were placed in the coronal third of the root canals. After a week, 2-mm-thick dentin disks were prepared from the coronal third of the roots, and the push-out test was performed using a universal testing machine. The data were analyzed using two-way ANOVA and independent t-test at a significance level of 0.05. Results. Regardless of the intracanal medicament, there was no significant difference between the overall bond strength of MTA (59.3±10 MPa) and CEM (55.8±11 MPa) (P=0.6). Furthermore, there were no significant differences in bond strength between the two intracanal medicament groups and the control group (P>0.05). Conclusion. Under the limitations of the current study, DAP, simvastatin, and TAP, as intracanal medicaments, did not adversely affect the push-out bond strength of CEM and MTA.

Combined Release of Antiseptic and Antibiotic Drugs from Visible Light Polymerized Biodegradable Nanocomposite Hydrogels for Periodontitis Treatment

The in situ application of the combination of different types of drugs revolutionized the area of periodontal therapy. The purpose of this study was to develop nanocomposite hydrogel (NCHG) as a pH-sensitive drug delivery system. To achieve local applicability of the NCHG in dental practice, routinely used blue-light photopolymerization was chosen for preparation. The setting time was 60 s, which resulted in stable hydrogel structures. Universal Britton–Robinson buffer solutions were used to investigate the effect of pH in the range 4–12 on the release of drugs that can be used in the periodontal pocket. Metronidazole was released from the NCHGs within 12 h, but chlorhexidine showed a much longer elution time with strong pH dependence, which lasted more than 7 days as it was corroborated by the bactericidal effect. The biocompatibility of the NCHGs was proven by Alamar-blue test and the effectiveness of drug release in the acidic medium was also demonstrated. This fast photo-polymerizable NCHG can help to establish a locally applicable combined drug delivery system which can be loaded with the required amount of medicines and can reduce the side effects of the systemic use of drugs that have to be used in high doses to reach an ideal concentration locally.

In vitro evaluation of disease-modifying antirheumatic drugs against rheumatoid arthritis associated pathogens of the oral microflora

OBJECTIVES

In the past, the human microbiome has consistently been associated with rheumatoid arthritis (RA) and disease activity. Here, we investigate the antimicrobial activity of disease-modifying antirheumatic drugs (DMARDs) against typical representatives of the oral microflora that have been associated with RA.

METHODS

DMARDs were screened for antimicrobial activity against bacteria that are associated with the pathogenesis of the disease and/or frequently isolated from the oral microflora of patients with RA. Screening was done by an agar diffusion assay and minimum inhibitory concentrations (MICs) of antimicrobial active substances were then determined by broth dilution.

RESULTS

Aurothiomalate and sulfasalazine demonstrated broad-spectrum antimicrobial activity, but with MICs ranging from 18 to >280 µg/mL and 150 to >600 µg/mL, respectively, only at supratherapeutic concentrations. Methotrexate showed antimicrobial activity only against Fusobacterium nucleatum and Viridans streptococci. The corresponding MICs were 3.75 to >30 µg/mL and 0.5-15 µg/mL, respectively, thus at least for streptococci, within the therapeutically achievable range. No other DMARD tested showed antimicrobial activity in the agar diffusion screening assay.

CONCLUSION

Methotrexate, sulfasalazine and aurothiomalate showed antimicrobial activity against a broad spectrum of RA associated pathogens of the oral microflora. While methotrexate showed relevant antimicrobial activity, and to a more limited extent aurothiomalate, sulfasalazine was active only at far supratherapeutic systemic concentrations. Nevertheless, given the highly species-dependent antimicrobial activity and the multiple ways it can affect the human microbiome, our results suggest a link between antimicrobially active antirheumatic drugs and their potential effect in the treatment of RA.

STATINSWITH POTENTIAL TO CONTROL PERIODONTITIS: FROM BIOLOGICAL MECHANISMS TO CLINICAL STUDIES

BACKGROUND

Statins are widely used for the treatment of hyperlipidemia. However, these drugs have pleiotropic effects that can be promising for the prevention and treatment of oral diseases, such as periodontitis.

HIGHLIGHT

This review aimed to identify preclinical, observational, and clinical studies that evaluate the effects and biological mechanisms of statins on oral cells and tissues and those using these drugs to treat periodontitis. A LITERATURE SURVEY HAS BEEN CONDUCTED IN PUBMED USING COMBINATIONS OF THE UNITERMS: "statins," "dentistry," "periodontal disease," and "periodontal treatment." In vitro findings showed positive statin results in cell lines related to alveolar bone metabolism by altering the signaling pathway Osteoprotegerin/Receptor Activator of Nuclear Factor Kappa B/Receptor Activator of Nuclear Factor Kappa B Ligand (OPG/RANK/RANKL), stimulating the production of alkaline phosphatase and osteocalcin, and reducing the production of matrix metalloproteinases (MMPs). Animal studies have shown a reduction in alveolar bone loss and osteoclastic activity, in addition to a reduction in inflammatory markers, such as IL-1, IL-6, and TNF-α, when statins were used prophylactically. Clinical trials showed a positive impact on clinical parameters, leading to a higher reduction in probing depth and gain in clinical attachment when a local statin was adjunctively associated with mechanical therapy.

CONCLUSION

Statins were shown to be promising for regenerating and stimulating bone activity, with great potential for treating chronic periodontitis. However, further studies are required to confirm its effectiveness.

In Search of Spectroscopic Signatures of Periodontitis: A SERS-Based Magnetomicrofluidic Sensor for Detection of Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans

Recently, Porphyromonas gingivalis, the keystone pathogen implicated in the development of gum disease (periodontitis), was detected in the brains of Alzheimer’s disease patients, opening up a fascinating possibility that it is also involved in the pathobiology of this neurodegenerative illness. To verify this hypothesis, an unbiased, specific, and sensitive method to detect this pathogen in biological specimens is needed. To this end, our interdisciplinary studies demonstrate that P. gingivalis can be easily identified by surface-enhanced Raman scattering (SERS). Moreover, based on SERS measurements, P. gingivalis can be distinguished from another common periodontal pathogen, Aggregatibacter actinomycetemcomitans, and also from ubiquitous oral Streptococcus spp. The results were confirmed by principal component analysis (PCA). Furthermore, we have shown that different P. gingivalis and A. actinomycetemcomitans strains can easily adsorb to silver-coated magnetic nanoparticles (Fe₂O₃@AgNPs). Thus, it is possible to magnetically separate investigated bacteria from other components of a specimen using the microfluidic chip. To obtain additional enhancement of the Raman signal, the NPs adsorbed to bacterial cells were magnetically attracted to the Si/Ag SERS platform. Afterward, the SERS spectra could be recorded. Such a time-saving procedure can be very helpful in rapid medical diagnostics and thus in starting the appropriate pharmacological therapy to prevent the development of periodontitis and associated comorbidities, e.g., Alzheimerʼs disease.

Therapeutic effects of antibiotics loaded cellulose nanofiber and κ-carrageenan oligosaccharide composite hydrogels for periodontitis treatment

Periodontitis is an inflammatory disease that can lead to the periodontal pocket formation and tooth loss. This study was aimed to develop antimicrobials loaded hydrogels composed of cellulose nanofibers (CNF) and κ-carrageenan oligosaccharides (CO) nanoparticles for the treatment of periodontitis. Two antimicrobial agents such as surfactin and Herbmedotcin were selected as the therapeutic agents and the hydrogels were formulated based on the increasing concentration of surfactin. The proposed material has high thermal stability, controlled release, and water absorption capacity. This study was proceeded by investigating the in vitro antibacterial and anti-inflammatory properties of the hydrogels. This material has strong antibacterial activity against periodontal pathogens such as Streptococcus mutans, Porphyromonas gingivalis, Fusobacterium nucleatum, and Pseudomonas aeruginosa. Moreover, a significant increase in malondialdehyde (MDA) production and a decrease in biofilm formation and metabolic activity of the bacteria was observed in the presence of hydrogel. Besides, it reduced the reactive oxygen species (ROS) generation, transcription factor, and cytokines production in human gingival fibroblast cells (HGF) under inflammatory conditions. In conclusion, the hydrogels were successfully developed and proven to have antibacterial and anti-inflammatory properties for the treatment of periodontitis. Thus, it can be used as an excellent candidate for periodontitis treatment.

Simvastatin enhanced antimicrobial effect of Ag+ against E. faecalis infection of dentine through PLGA co-delivery submicron particles

Enterococcus faecalis (E. faecalis) is one of the dominant bacteria for refractory infections of teeth. Silver ions (Ag⁺) have been proved to be a strong bactericide but with high cytotoxicity and discoloration property. Simvastatin is an agent used for dyslipidemia treatment and has anti-inflammatory property. In this study, Ag⁺ and simvastatin were for the first time used in combination, and poly (lactide-co-glycolide) (PLGA) submicron particles carrying both Ag⁺ and simvastatin (AgS-PLGA) were fabricated for further investigations. Results confirmed the enhanced antibacterial activity against E. faecalis of Ag⁺ by simvastatin. AgS-PLGA could release both Ag⁺ and simvastatin for 24 days and also showed enhanced antibacterial activities. On dentin slices, AgS-PLGA could enter dentinal tubules by ultrasonic activation and inhibit the colonization of E. faecalis. AgS-PLGA showed no cytotoxicity on MC3T3-E1 cells and slight suppressive effect on RAW-264.7 cells, and could reduce the secretion of IL-6 and IL-1β of RAW-264.7 cells. AgS-PLGA could be developed as a new biomaterial for infection and inflammation control for dental and related medical treatments.

Statins-based prophylactic mouthwash and nasal spray may protect against coronavirus disease 2019

The novel coronavirus 2019 (COVID‐19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), has caused an unprecedented healthcare crisis. SARS‐CoV‐2 gets access into the human body mainly through the nose and the mouth and invades these mucosae in its destination to the pulmonary tissues. Thus, the oral and nasal mucosae serve as the main routes and reservoirs for aerosolized transmission of the viral particles to the external environment and hence infection transmission. Statins have been shown to have antimicrobial, antiviral, antifungal, anti‐inflammatory, immunomodulatory, and antioxidant properties. Therefore, we hypothesize that using statins-based prophylactic mouthwashes will reduce COVID‐19 transmission in dental settings.

Development of a thermosensitive statin loaded chitosan-based hydrogel promoting bone healing

Statins have been proposed as potential adjuvant to periodontal treatment due to their pleiotropic properties. A new thermosensitive chitosan hydrogel loaded with statins (atorvastatin and lovastatin) nanoemulsions was synthesized to allow a spatially controlled local administration of active compounds at lesion site. Spontaneous nano-emulsification method was used to synthesize statins loaded nanoemulsions. In vitro, atorvastatin and lovastatin loaded nanoemulsions were cytocompatible and were able to be uptake by oral epithelial cells. Treatment of Porphyromonas gingivalis infected oral epithelial cells and gingival fibroblasts with atorvastatin and lovastatin loaded nanoemulsions decreased significantly pro-inflammatory markers expression (TNF-α and IL-1β) and pro-osteoclastic RANKL. Nevertheless, such treatment induced the expression of Bone sialoprotein 2 (BSP2) in osteoblast emphasizing the pro-healing properties of atorvastatin and lovastatin nanoemulsions. In vivo, in a calvarial bone defect model (2 mm), treatment with the hydrogel loaded with atorvastatin and lovastatin nanoemulsions induced a significant increase of the neobone formation in comparison with systemic administration of statins. This study demonstrates the potential of this statins loaded hydrogel to improve bone regeneration and to decrease soft tissue inflammation. Its use in the specific context of periodontitis management could be considered in the future with a reduced risk of side effects.

The effects of statins on dental and oral health: a review of preclinical and clinical studies

The statin family of drugs are safe and effective therapeutic agents for the treatment of arteriosclerotic cardiovascular disease (CVD). Due to a wide range of health benefits in addition to their cholesterol lowering properties, statins have recently attracted significant attention as a new treatment strategy for several conditions, which are not directly related to normalizing a lipid profile and preventing CVD. Statins exert a variety of beneficial effects on different aspects of oral health, which includes their positive effects on bone metabolism, their anti-inflammatory and antioxidant properties, and their potential effects on epithelization and wound healing. Additionally, they possess antimicrobial, antiviral, and fungicidal properties, which makes this class of drugs attractive to the field of periodontal diseases and oral and dental health. However, to the best of our knowledge, there has been no comprehensive study to date, which has investigated the effects of statin drugs on different aspects of dental and oral health. Therefore, the primary objective of this paper was to review the effect of statins on dental and oral health. Results of our extensive review have indicated that statins possess remarkable and promising effects on several aspects of dental and oral health including chronic periodontitis, alveolar bone loss due to either extraction or chronic periodontitis, osseointegration of implants, dental pulp cells, orthodontic tooth movement, and orthodontic relapse, tissue healing (wound/bone healing), salivary gland function, and finally, anti-cancer effects. Hence, statins can be considered as novel, safe, inexpensive, and widely-accessible therapeutic agents to improve different aspects of dental and oral health.

Periodontal therapy for primary or secondary prevention of cardiovascular disease in people with periodontitis

BACKGROUND

There may be an association between periodontitis and cardiovascular disease (CVD); however, the evidence so far has been uncertain about whether periodontal therapy can help prevent CVD in people diagnosed with chronic periodontitis. This is the second update of a review originally published in 2014, and first updated in 2017. Although there is a new multidimensional staging and grading system for periodontitis, we have retained the label 'chronic periodontitis' in this version of the review since available studies are based on the previous classification system.

OBJECTIVES

To investigate the effects of periodontal therapy for primary or secondary prevention of CVD in people with chronic periodontitis.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the Cochrane Oral Health's Trials Register, CENTRAL, MEDLINE, Embase, and CINAHL, two trials registries, and the grey literature to September 2019. We placed no restrictions on the language or date of publication. We also searched the Chinese BioMedical Literature Database, the China National Knowledge Infrastructure, the VIP database, and Sciencepaper Online to August 2019.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared active periodontal therapy to no periodontal treatment or a different periodontal treatment. We included studies of participants with a diagnosis of chronic periodontitis, either with CVD (secondary prevention studies) or without CVD (primary prevention studies).

DATA COLLECTION AND ANALYSIS

Two review authors carried out the study identification, data extraction, and 'Risk of bias' assessment independently and in duplicate. They resolved any discrepancies by discussion, or with a third review author. We adopted a formal pilot-tested data extraction form, and used the Cochrane tool to assess the risk of bias in the studies. We used GRADE criteria to assess the certainty of the evidence.

MAIN RESULTS

We included two RCTs in the review. One study focused on the primary prevention of CVD, and the other addressed secondary prevention. We evaluated both as being at high risk of bias. Our primary outcomes of interest were death (all-cause and CVD-related) and all cardiovascular events, measured at one-year follow-up or longer. For primary prevention of CVD in participants with periodontitis and metabolic syndrome, one study (165 participants) provided very low-certainty evidence. There was only one death in the study; we were unable to determine whether scaling and root planning plus amoxicillin and metronidazole could reduce incidence of all-cause death (Peto odds ratio (OR) 7.48, 95% confidence interval (CI) 0.15 to 376.98), or all CVD-related death (Peto OR 7.48, 95% CI 0.15 to 376.98). We could not exclude the possibility that scaling and root planning plus amoxicillin and metronidazole could increase cardiovascular events (Peto OR 7.77, 95% CI 1.07 to 56.1) compared with supragingival scaling measured at 12-month follow-up. For secondary prevention of CVD, one pilot study randomised 303 participants to receive scaling and root planning plus oral hygiene instruction (periodontal treatment) or oral hygiene instruction plus a copy of radiographs and recommendation to follow-up with a dentist (community care). As cardiovascular events had been measured for different time periods of between 6 and 25 months, and only 37 participants were available with at least one-year follow-up, we did not consider the data to be sufficiently robust for inclusion in this review. The study did not evaluate all-cause death and all CVD-related death. We are unable to draw any conclusions about the effects of periodontal therapy on secondary prevention of CVD.

AUTHORS' CONCLUSIONS

For primary prevention of cardiovascular disease (CVD) in people diagnosed with periodontitis and metabolic syndrome, very low-certainty evidence was inconclusive about the effects of scaling and root planning plus antibiotics compared to supragingival scaling. There is no reliable evidence available regarding secondary prevention of CVD in people diagnosed with chronic periodontitis and CVD. Further trials are needed to reach conclusions about whether treatment for periodontal disease can help prevent occurrence or recurrence of CVD.

Fusobacterium nucleatum Facilitates Apoptosis, ROS Generation, and Inflammatory Cytokine Production by Activating AKT/MAPK and NF-κB Signaling Pathways in Human Gingival Fibroblasts

Fusobacterium nucleatum (F. nucleatum) plays key roles in the initiation and progression of periodontitis. However, the pathogenic effect of F. nucleatum on human oral tissues and cells has not been fully evaluated. In this study, we aimed to analyze the pathogenic effects of F. nucleatum on human gingival fibroblasts (GFs) and clarify the potential mechanisms. RNA-sequencing analysis confirmed that F. nucleatum significantly altered the gene expression of GF as the stimulation time increased. Cell counting and EdU-labeling assays indicated that F. nucleatum inhibited GF proliferation and promoted cell apoptosis in a time- and dose-dependent manner. In addition, cell apoptosis, intracellular reactive oxygen species (ROS) generation, and proinflammatory cytokine production were dramatically elevated after F. nucleatum stimulation. Furthermore, we found that the AKT/MAPK and NF-κB signaling pathways were significantly activated by F. nucleatum infection and that a large number of genes related to cellular proliferation, apoptosis, ROS, and inflammatory cytokine production downstream of AKT/MAPK and NF-κB signaling pathways were significantly altered in F. nucleatum-stimulated GFs. These findings suggest that F. nucleatum inhibits GF proliferation and promotes cell apoptosis, ROS generation, and inflammatory cytokine production partly by activating the AKT/MAPK and NF-κB signaling pathways. Our study opens a new window for understanding the pathogenic effects of periodontal pathogens on the host oral system.

Guided tissue regeneration of intrabony defects with perforated barrier membranes, simvastatin, and EDTA root surface modification: A clinical and biochemical study

BACKGROUND

Perforated barrier membranes (PBM) were suggested to enhance periodontal regeneration by allowing positive charity of wanted elements from the gingival tissue side. The present study was designed to evaluate clinically and biochemically the use of PBM combined with simvastatin (SMV) gel with and without an associated EDTA gel root surface etching as a suggested option that could improve SMV availability and clinical outcomes of PBM.

METHODS

Forty patients having moderate-to-severe chronic periodontitis with 40 intrabony defects were randomly divided into four treatment groups (10 sites each). Patients in group 1 received 1.2% SMV gel and covering the defect with occlusive membrane (OM). Patients in group 2 received 1.2% SMV gel and covering the defect with PBM. Group 3 received 24% EDTA root surface etching, 1.2% SMV gel, and defect coverage with OM (eOM). Patients in group 4 were treated as in group 3 but the defect was covered with PBM (ePBM). Clinical parameters were recorded at baseline before surgical procedures and were reassessed at 6 and 9 months after therapy. The mean concentration of SMV in gingival crevicular fluid (GCF) was estimated by reverse-phase high-performance liquid chromatography at days 1, 7, 14, 21, and 30.

RESULTS

At 6- and 9-month observation periods, groups 3 and 4 showed a statistically significant improvement in PD reduction and CAL gain compared with groups 1 and 2. Group 4 showed a statistically significant more defect fill compared with groups 1, 2, and 3 (P ≤ .05). Group 2 showed statistically significant higher defect fill compared with group 1 and group 3 (P < .05). Bone density was significantly increased with no significant difference between the four groups at 6- and 9-month observation periods. SMV-GCF concentration in group 4 showed the highest mean concentration with no significant difference than that of group 3.

CONCLUSION

The use of perforated barrier membranes in association with SMV enhances the clinical hard tissue parameters compared with occlusive ones in treating intrabony periodontal defects. Moreover, EDTA root surface treatment could enhance SMV availability in the defect area.

Quercetin Inhibits Inflammatory Response Induced by LPS from Porphyromonas gingivalis in Human Gingival Fibroblasts via Suppressing NF-κB Signaling Pathway

Quercetin, a natural flavonol existing in many food resources, has been reported to be an effective antimicrobial and anti-inflammatory agent for restricting the inflammation in periodontitis. In this study, we aimed to investigate the anti-inflammatory effects of quercetin on Porphyromonas gingivalis (P. gingivalis) lipopolysaccharide- (LPS-) stimulated human gingival fibroblasts (HGFs). HGFs were pretreated with quercetin prior to LPS stimulation. Cell viability was evaluated by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. The levels of inflammatory cytokines, including interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α), along with chemokine interleukin-8 (IL-8), were determined by enzyme-linked immunosorbent assay (ELISA). The mRNA levels of IL-1β, IL-6, IL-8, TNF-α, IκBα, p65 subunit of nuclear factor-kappa B (NF-κB), peroxisome proliferator-activated receptor-γ (PPAR-γ), liver X receptor α (LXRα), and Toll-like receptor 4 (TLR4) were measured by real-time quantitative PCR (RT-qPCR). The protein levels of IκBα, p-IκBα, p65, p-p65, PPAR-γ, LXRα, and TLR4 were characterized by Western blotting. Our results demonstrated that quercetin inhibited the LPS-induced production of IL-1β, IL-6, IL-8, and TNF-α in a dose-dependent manner. It also suppressed LPS-induced NF-κB activation mediated by TLR4. Moreover, the anti-inflammatory effects of quercetin were reversed by the PPAR-γ antagonist of GW9662. In conclusion, these results suggested that quercetin attenuated the production of IL-1β, IL-6, IL-8, and TNF-α in P. gingivalis LPS-treated HGFs by activating PPAR-γ which subsequently suppressed the activation of NF-κB.

Efficacy of locally-delivered statins adjunct to non-surgical periodontal therapy for chronic periodontitis: a Bayesian network analysis

BACKGROUND

Studies indicate locally-delivered statins offer additional benefits to scaling and root planning (SRP), however, it is still hard to say which type of statins is better. This network meta-analysis aimed to assess the effect of locally-delivered statins and rank the most efficacious statin for treating chronic periodontitis (CP) in combination with SRP.

METHODS

We screened four literature databases (Pubmed, Embase, Cochrane Library, and Web of Science) for randomized controlled clinical trials (RCTs) published up to June 2018 that compared different statins in the treatment of chronic periodontitis. The outcomes analyzed were changes in intrabony defect depth (IBD), pocket depth (PD), and clinical attachment level (CAL). We carried out Bayesian network meta-analysis of CP without systemic diseases. Traditional and Bayesian network meta-analyses were conducted using random-effects models.

RESULTS

Greater filling of IBD, reduction in PD, and gain in CAL were observed for SRP treated in combination with statins when compared to SRP alone for treating CP without systemic diseases. Specifically, SRP+ Atorvastatin (ATV) (mean difference [MD]: 1.5 mm, 1.4 mm, 1.8 mm, respectively), SRP + Rosuvastatin (RSV) (MD: 1.8 mm, 2.0 mm, 2.1 mm, respectively), and SRP + Simvastatin (SMV) (MD: 1.1 mm, 2.2 mm, 2.1 mm, respectively) were identified. However, no difference was found among the statins tested. In CP patients with type 2 diabetic (T2DM) or in smokers, additional benefits were observed from locally delivered statins.

CONCLUSION

Local statin use adjunctive to SRP confers additional benefits in treating CP by SRP, even in T2DM and smokers. RSV may be the best one to fill in IBD. However, considering the limitations of this study, clinicians must use cautious when applying the results and further studies are required to explore the efficacy of statins in CP with or without the risk factors (T2DM comorbidity or smoking history).

Contribution of Statins towards Periodontal Treatment: A Review

The pleiotropic effects of statins have been evaluated to assess their potential benefit in the treatment of various inflammatory and immune-mediated diseases including periodontitis. Herein, the adjunctive use of statins in periodontal therapy in vitro, in vivo, and in clinical trials was reviewed. Statins act through several pathways to modulate inflammation, immune response, bone metabolism, and bacterial clearance. They control periodontal inflammation through inhibition of proinflammatory cytokines and promotion of anti-inflammatory and/or proresolution molecule release, mainly, through the ERK, MAPK, PI3-Akt, and NF-κB pathways. Moreover, they are able to modulate the host response activated by bacterial challenge, to prevent inflammation-mediated bone resorption and to promote bone formation. Furthermore, they reduce bacterial growth, disrupt bacterial membrane stability, and increase bacterial clearance, thus averting the exacerbation of infection. Local statin delivery as adjunct to both nonsurgical and surgical periodontal therapies results in better periodontal treatment outcomes compared to systemic delivery. Moreover, combination of statin therapy with other regenerative agents improves periodontal healing response. Therefore, statins could be proposed as a potential adjuvant to periodontal therapy. However, optimization of the combination of their dose, type, and carrier could be instrumental in achieving the best treatment response.

Local Application of Pyrophosphorylated Simvastatin Prevents Experimental Periodontitis

PURPOSE

Simvastatin (SIM), a HMG-CoA reductase inhibitor widely prescribed for hypercholesterolemia, has been reported to ameliorate inflammation and promote osteogenesis. Its clinical applications on these potential secondary indications, however, have been hampered by its lack of osteotropicity and poor water solubility. To address this challenge, we propose to design and evaluate the therapeutic efficacy of a novel simvastatin prodrug with better water solubility and bone affinity.

METHOD

The prodrug (SIM-PPi) was synthesized by directly conjugating a SIM trimer to a pyrophosphate (PPi). It was characterized and evaluated in vitro for its water solubility, osteotropicity, toxicity, anti-inflammatory and osteoinductive properties. It was then tested for anti-inflammatory and osteoinductive properties in vivo by three weekly injections into gingiva of a ligature-induced experimental periodontitis rat model.

RESULTS

In vitro studies showed that SIM-PPi has greatly improved water-solubility of SIM and shows strong binding to hydroxyapatite (HA). In macrophage culture, SIM-PPi inhibited LPS-induced pro-inflammatory cytokines (IL-1β, IL-6). In osteoblast culture, it was found to significantly increase alkaline phosphatase (ALP) activity with accelerated mineral deposition, confirming the osteogenic potential of SIM-PPi. When tested in vivo on an experimental periodontal bone-loss model, SIM-PPi exhibited a superior prophylactic effect compared to dose equivalent SIM in reducing inflammatory cells and in preserving alveolar bone structure, as shown in the histological and micro-CT data.

CONCLUSION

SIM-PPi may have the potential to be further developed for better clinical management of bone loss associated with periodontitis.

Statins in nonsurgical and surgical periodontal therapy. A systematic review and meta-analysis of preclinical in vivo trials

The cholesterol-lowering drugs, statins, possess anti-inflammatory, antimicrobial and pro-osteogenic properties, and thus have been tested as an adjunct to periodontal treatment. The present systematic review aimed to answer the following focused research question: What is the effect of local and/or systemic statin use on periodontal tissues in preclinical in vivo studies of experimentally induced periodontitis (EIP) and/or acute/chronified periodontal defect (ACP) models? A literature search (of Medline/PubMed, Embase/Ovid, CENTRAL/Ovid) using the following main eligibility criteria was performed: (i) English or German language; (ii) controlled preclinical in vivo trials; (iii) local and/or systemic statin use in EIP and/or ACP models; and (iv) quantitative evaluation of periodontal tissues (i.e., alveolar bone level/amount, attachment level, cementum formation, periodontal ligament formation). Sixteen studies in EIP models and 7 studies in ACP models evaluated simvastatin, atorvastatin or rosuvastatin. Thirteen of the EIP (81%) and 2 of the ACP (29%) studies presented significantly better results in terms of alveolar bone level/amount in favor of statins. Meta-analysis based on 14 EIP trials confirmed a significant benefit of local and systemic statin use (P < .001) in terms of alveolar bone level/amount; meta-regression revealed that statin type exhibited a significant effect (P = .014) in favor of atorvastatin. Three studies reported a significantly higher periodontal attachment level in favor of statin use (P < .001). Complete periodontal regeneration was never observed; furthermore, statins did not exert any apparent effect on cementum formation. Neither local nor systemic use of statins resulted in severe adverse effects. Statin use in periodontal indications has a positive effect on periodontal tissue parameters, supporting the positive results already observed in clinical trials. Nevertheless, not all statins available have been tested so far, and further research is needed to identify the maximum effective concentration/dose and optimal carrier.

The effect of local and systemic statin use as an adjunct to non-surgical and surgical periodontal therapy-A systematic review and meta-analysis

OBJECTIVES

To evaluate the effect of local and/or systemic statin use as an adjunct to non-surgical and/or surgical periodontal therapy.

DATA

Literature search according to PRISMA guidelines with the following eligibility criteria: (a) English or German language; (b) interventional studies; (c) statins as monotherapy or as an adjunct to non-surgical and/or surgical treatment of periodontitis; (d) clinical and/or radiographic treatment effect size of statin intake reported.

SOURCES

Medline (PubMed), Embase (Ovid), CENTRAL (Ovid).

STUDY SELECTION

Thirteen clinical studies regarding local application and 2 with systemic administration of statins as an adjunct to non-surgical treatment (SRP) and 4 studies regarding intrasurgical statin application with a maximum follow-up of 9 months could be included; simvastatin, atorvastatin, and rosuvastatin were used. Local but not systemic statin application as an adjunct to SRP yielded significantly larger probing pocket depth (PD), radiographic defect depth (RDD), and bleeding index reduction, and larger clinical attachment level gain, and less residual PD and RDD (p≤0.016); rosuvastatin appeared as the most efficacious. Three of 4 studies reported a significant positive effect of intrasurgical statin application. No adverse events were reported after statin use. The vast majority of the included studies were from the same research group.

CONCLUSIONS

Significant additional clinical and radiographic improvements are obtained after local, but not systemic, statin use as an adjunct to SRP in deep pockets associated with intrabony defects and seemingly with furcation defects; intrasurgical statin application seems similarly beneficial. Confirmation of these results, and especially of the effect size, from other research groups is warranted.

Periodontal therapy for the management of cardiovascular disease in patients with chronic periodontitis

BACKGROUND

There is an association between chronic periodontitis and cardiovascular disease (CVD). However, it is not known whether periodontal therapy could prevent or manage CVD in patients with chronic periodontitis.

OBJECTIVES

The objective of this systematic review was to investigate the effects of periodontal therapy in preventing the occurrence of, and management or recurrence of, CVD in patients with chronic periodontitis.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 31 August 2017), the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library, 2017, Issue 7), MEDLINE Ovid (1946 to 31 August 2017), Embase Ovid (1980 to 31 August 2017) and the Cumulative Index to Nursing and Allied Health Literature (CINAHL EBSCO) (1937 to 31 August 2017) . The US National Institutes of Health Trials Registry (ClinicalTrials.gov), the World Health Organization International Clinical Trials Registry Platform and Open Grey were searched for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases.We also searched the Chinese BioMedical Literature Database (1978 to 27 August 2017), the China National Knowledge Infrastructure (1994 to 27 August 2017), the VIP database (1989 to 27 August 2017) and Sciencepaper Online (2003 to 27 August 2017).

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs were considered eligible. Studies were selected if they included patients with a diagnosis of chronic periodontitis and previous CVD (secondary prevention studies) or no CVD (primary prevention studies); patients in the intervention group received active periodontal therapy compared to maintenance therapy, no periodontal treatment or another kind of periodontal treatment in the control group.

DATA COLLECTION AND ANALYSIS

Two review authors carried out the study identification, data extraction and risk of bias assessment independently and in duplicate. Any discrepancies between the two authors were resolved by discussion or with a third review author. A formal pilot-tested data extraction form was adopted for the data extraction, and the Cochrane tool for risk of bias assessment was used for the critical appraisal of the literature.

MAIN RESULTS

No studies were identified that assessed primary prevention of CVD in people with periodontitis. One study involving 303 participants with ≥ 50% blockage of one coronary artery or a coronary event within three years, but not the three months prior, was included. The study was at high risk of bias due to deviation from the protocol treatment allocation and lack of follow-up data. The trial compared scaling and root planing (SRP) with community care for a follow-up period of six to 25 months. No data on deaths (all-cause or CVD-related) were reported. There was insufficient evidence to determine the effect of SRP and community care in reducing the risk of CVD recurrence in patients with chronic periodontitis (risk ratio (RR) 0.72; 95% confidence interval (CI) 0.23 to 2.22; very low quality evidence). The effects of SRP compared with community care on high-sensitivity C-reactive protein (hs-CRP) (mean difference (MD) 0.62; -1.45 to 2.69), the number of patients with high hs-CRP (RR 0.77; 95% CI 0.32 to 1.85) and adverse events (RR 9.06; 95% CI 0.49 to 166.82) were also not statistically significant. The study did not assess modifiable cardiovascular risk factors, other blood test results, heart function parameters or revascularisation procedures.

AUTHORS' CONCLUSIONS

We found very low quality evidence that was insufficient to support or refute whether periodontal therapy can prevent the recurrence of CVD in the long term in patients with chronic periodontitis. No evidence on primary prevention was found.

Statins: antimicrobial resistance breakers or makers?

Introduction

The repurposing of non-antibiotic drugs as adjuvant antibiotics may help break antimicrobial resistance (AMR). Statins are commonly prescribed worldwide to lower cholesterol. They also possess qualities of AMR “breakers”, namely direct antibacterial activity, synergism with antibiotics, and ability to stimulate the host immune system. However, statins’ role as AMR breakers may be limited. Their current extensive use for cardiovascular protection might result in selective pressures for resistance, ironically causing statins to be AMR “makers” instead. This review examines statins’ potential as AMR breakers, probable AMR makers, and identifies knowledge gaps in a statin-bacteria-human-environment continuum. The most suitable statin for repurposing is identified, and a mechanism of antibacterial action is postulated based on structure-activity relationship analysis.

Methods

A literature search using keywords “statin” or “statins” combined with “minimum inhibitory concentration” (MIC) was performed in six databases on 7th April 2017. After screening 793 abstracts, 16 relevant studies were identified. Unrelated studies on drug interactions; antifungal or antiviral properties of statins; and antibacterial properties of mevastatin, cerivastatin, antibiotics, or natural products were excluded. Studies involving only statins currently registered for human use were included.

Results

Against Gram-positive bacteria, simvastatin generally exerted the greatest antibacterial activity (lowest MIC) compared to atorvastatin, rosuvastatin, and fluvastatin. Against Gram-negative bacteria, atorvastatin generally exhibited similar or slightly better activity compared to simvastatin, but both were more potent than rosuvastatin and fluvastatin.

Discussion

Statins may serve as AMR breakers by working synergistically with existing topical antibiotics, attenuating virulence factors, boosting human immunity, or aiding in wound healing. It is probable that statins’ mechanism of antibacterial activity involves interference of bacterial cell regulatory functions via binding and disrupting cell surface structures such as wall teichoic acids, lipoteichoic acids, lipopolysaccharides, and/or surface proteins. The widespread use of statins for cardiovascular protection may favor selective pressures or co-selection for resistance, including dysbiosis of the human gut microbiota, sublethal plasma concentrations in bacteremic patients, and statin persistence in the environment, all possibly culminating in AMR.

Conclusion

Simvastatin appears to be the most suitable statin for repurposing as a novel adjuvant antibiotic. Current evidence better supports statins as potential AMR breakers, but their role as plausible AMR makers cannot be excluded. Elucidating the mechanism of statins’ antibacterial activity is perhaps the most important knowledge gap to address as this will likely clarify statins’ role as AMR breakers or makers.

A Population-Based Cohort Study on the Drug-Specific Effect of Statins on Sepsis Outcome

BACKGROUND

Whether statin treatment, proved by recent experimental studies to have an antimicrobial activity, exerts a drug- or a class-specific effect in sepsis remains unknown.

METHODS

Short-term mortality in patients with sepsis was analyzed using data from the National Health Insurance Research Database. Use of statins was defined as the cumulative use of a specific statin (atorvastatin, simvastatin, or rosuvastatin) for > 30 days prior to the index sepsis admission. We determined the association between statin and sepsis outcome by multivariate-adjusted Cox models and propensity score (PS)-matched analysis, using a 1:1:1 PS matching technique.

RESULTS

A total of 52,737 patients with sepsis fulfilled the inclusion criteria, of which 1,855 were prescribed atorvastatin, 916 were prescribed simvastatin, and 732 were prescribed rosuvastatin. Compared with nonusers, simvastatin (hazard ratio [HR], 0.72; 95% CI, 0.58-0.90) and atorvastatin (HR, 0.78; 95% CI, 0.68-0.90) were associated with an improved 30-day survival, whereas rosuvastatin was not (HR, 0.87; 95% CI, 0.73-1.04). Using rosuvastatin as the reference, atorvastatin (HR, 0.79; 95% CI, 0.64-0.99) and simvastatin (HR, 0.77; 95% CI, 0.59-0.99) had superior effectiveness in preventing mortality.

CONCLUSIONS

Compatible with in vitro experimental findings, our results suggest that the drug-specific effect of statins on sepsis is not correlated to their lipid-lowering potency.

Does short preoperative statin therapy prevent infectious complications in adults undergoing cardiac or non-cardiac surgery? A meta-analysis of 5 randomized placebo-controlled trials

Objectives:

To evaluate the effect of preoperative statin therapy on the incidence of postoperative infection.

Methods:

This systematic review of the literature was carried out in August 2015. Studies were retrieved via PubMed, Embase, and the Cochrane Library (1980 to 2015), and the reference files were limited to English-language articles. We used a standardized protocol, and a meta-analysis was performed for data abstraction.

Results:

Five studies comprising 1,362 patients qualified for the analysis. The incidence of postoperative infections in the statin group (1.1%) was not significantly lower than that in the placebo group (2.4%), with a risk ratio (RR) of 0.56 (95% confidence interval [CI] 0.24-1.33, p=0.19). Patients of 3 studies underwent cardiac surgery. The aggregated results of these studies failed to show significant differences in postoperative infection when a fixed effects model was used (RR: 0.39; 95% CI: 0.08-1.97, p=0.26].

Conclusions:

We failed to find sufficient evidence to support the association between statin use and postoperative infectious complications. The absence of any evidence for a beneficial effect in available randomized trials reduces the likelihood of a causal effect as reported in observational studies.

Effect of 1.2% of simvastatin gel as a local drug delivery system on Gingival Crevicular Fluid interleukin-6 & interleukin-8 levels in non surgical treatment of chronic periodontitis patients

AIM

The present study was carried out to evaluate the effect of 1.2% simvastatin gel as local drug delivery (LDD) system on Gingival Crevicular Fluid (GCF) Interleukin -6 (IL-6) and Interleukin-8 (IL-8) levels in chronic periodontitis patients, in addition to scaling and root planing (SRP).

METHODS

A total of 46 chronic periodontitis patients were equally divided into two groups. Group I patients were treated by SRP; Group II patients were treated by SRP followed by LDD of 1.2% simvastatin (SMV) gel. Plaque index (PI), Gingival index(GI), Sulcus Bleeding Index (SBI), Probing pocket depth (PPD) and Relative clinical attachment level (CAL) were recorded & GCF samples were collected at baseline (0day) and at 45th day from both the groups. The collected GCF samples were analysed for IL-6 and IL-8 levels with enzyme-linked immunosorbent assay (ELISA).

RESULTS

Both the groups showed significant reduction in all the clinical parameters scores and IL-6 and IL-8 levels after non-surgical periodontal therapy (SRP for group I/SRP+1.2% SMV gel for group II) in contrast to baseline values. However, a greater reduction was observed in group II. A non-significant positive correlation was observed between clinical parameters and IL-6 and IL-8 levels except at baseline, a significant correlation was observed between PPD &IL 6 levels in group II.

CONCLUSIONS

In adjunct to SRP, 1.2% Simvastatin gel acts as an effective local drug delivery agent for the management of chronic periodontitis.

Metformin Inhibits Porphyromonas gingivalis Lipopolysaccharide-Influenced Inflammatory Response in Human Gingival Fibroblasts via Regulating Activating Transcription Factor-3 Expression

BACKGROUND

Chronic periodontitis, one of the most prevalent oral diseases, is associated with Porphyromonas gingivalis (Pg) lipopolysaccharide (LPS) infection and has profound effects on type 2 diabetes mellitus (t2DM). Metformin, a well-known antidiabetic agent, has been reported to exert anti-inflammatory effects on various cells. This study aims to investigate the role of metformin on LPS-influenced inflammatory response in human gingival fibroblasts (HGFs).

METHODS

Dose-dependent additive effects of metformin on LPS-influenced HGFs were detected. Cell-counting assay was used to determine effects of metformin and LPS on viability of HGFs. Enzyme-linked immunosorbent assay and quantitative real-time polymerase chain reaction (qRT-PCR) were applied to detect levels of interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α in differently treated cells. Activating transcription factor-3 (ATF3) small interfering (si)RNA transfection was used to determine the mechanism of metformin action, and the transfection efficiency was observed by fluorescence microscope. Effects of ATF3 knockdown were determined by qRT-PCR and Western blot.

RESULTS

Results showed that 5 μg/mL Pg LPS and 0.1, 0.5, and 1 mM metformin exhibited no toxicity to HGFs, and metformin inhibited LPS-influenced IL-1β, IL-6, and TNF-α production in a dose-dependent manner. Metformin and LPS could synergistically facilitate ATF3 expression, and ATF3 knockdown abolished inhibitory effects of metformin on LPS-influenced inflammatory cytokine production in HGFs.

CONCLUSION

The present study confirms that metformin suppresses LPS-enhanced IL-6, IL-1β, and TNF-α production in HGFs via increasing ATF3 expression.

Bacteriostatic Effect of Simvastatin on Selected Oral Streptococci in Vitro

CONTEXT AND OBJECTIVE

Simvastatin is a widely used cholesterol-lowering drug, which has been found to have a number of pleiotropic effects. The aim of this study was to evaluate the antimicrobial effectiveness of simvastatin against selected oral streptococci as determined by the minimum inhibitory concentration (MIC).

METHODS

Streptococcus mutans, Streptococcus sanguis, Streptococcus anginosus, and Streptococcus salivarius were the test microorganisms. The serial dilution method was used to determine the MIC of simvastatin against these organisms. The MIC was defined as the lowest concentration of simvastatin that completely inhibited growth of the test organisms.

RESULTS

The data indicate that simvastatin inhibits the growth of the test organisms, with MIC's ranging from 7.8 to 15.6 μg/ml.

CONCLUSIONS

Simvastatin has MIC's against the selected bacteria that compare favorably with reported values for topical agents such as essential oil, chlorhexidine gluconate, and triclosan. The levels of simvastatin required to inhibit bacterial growth of oral bacteria exceed the reported levels of the drug found in plasma or crevicular fluid of patients who are treated with this cholesterol-lowering drug. However, clinical studies are warranted to investigate the potential use of simvastatin as a novel antiplaque agent that could be used in local drug delivery to the oral cavity of those patients who are prescribed this cholesterol-lowering drug.

Effect of hyperlipidemia on response to nonsurgical periodontal therapy: Statin users versus nonusers

Objective:

To evaluate the response to nonsurgical periodontal therapy among hyperlipidemic subjects and whether statin use by hyperlipidemic subjects influences the response.

Materials and Methods:

This study was conducted on 107 chronic periodontitis subjects (35 normolipidemic [NL] controls, 36 hyperlipidemics on nonpharmacological therapy and 36 hyperlipidemics on statins). Periodontal (plaque index, gingival index [GI], probing depth [PD], and clinical attachment level [CAL]) and biochemical (plasma triglyceride [TG], total cholesterol [TC], low-density lipoprotein cholesterol [LDL-C], and high-DL-C [HDL-C] levels) examination was done at baseline and 3 months after nonsurgical periodontal treatment.

Results:

Both the NL and statin groups exhibited significantly greater improvement in GI as compared to the hyperlipidemic group on nonpharmacological therapy (P = 0.004 and 0.006, respectively). Mean change in PD correlated negatively with baseline TC (r = −0.306) and LDL-C (r = −0.360) while mean change in GI positively correlated with baseline HDL-C (r = 0.219). Regression analyses revealed that mean change in PD was negatively associated with LDL-C (β = −0.358, P < 0.001) while mean change in GI was positively associated with HDL-C (β = 0.219, P = 0.023).

Conclusions:

While higher baseline lipid levels were somewhat detrimental to the resolution of inflammation postperiodontal treatment, the inclusion of statin therapy among hyperlipidemic subjects seemed to improve clinical response as compared to those devoid of the drug. The findings of the study are suggestive of a possible adjunctive role of statins in periodontal treatment that warrants future studies.

Systematic review of the in vitro effects of statins on oral and perioral microorganisms

Statins are medications administered orally and are widely used for lowering the blood cholesterol level. The aim of this study was to investigate the effects of orally administered statins on microorganisms infecting oral and perioral tissues. We performed a systematic review of published studies of the in vitro antimicrobial effects of statins on bacteria, viruses, and fungi, and searched PubMed, Web of Science, Cochrane Central, and Google scholar. Studies show that most statins exhibit antimicrobial effects against various oral microorganisms. Simvastatin is most effective against the periodontal pathogens Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis, and against most dental plaque bacteria, including Streptococcus mutans. Statins also exhibit antiviral properties against human cytomegalovirus, hepatitis B virus, and hepatitis C virus, and have antifungal properties against Candida albicans, Aspergillus fumigatus, and Zygomycetes spp. There were notable differences in the minimum inhibitory concentrations (MICs) between different studies, which may be attributed to differences in study design. Further studies are warranted to ascertain if statins can be solubilized so that patients, who have been prescribed statins for cardiovascular diseases, can use the medication as a swish and swallow, giving patients the added benefit of the antimicrobial action topically in the mouth against infectious oral diseases.

Tormentic acid inhibits LPS-induced inflammatory response in human gingival fibroblasts via inhibition of TLR4-mediated NF-κB and MAPK signalling pathway

OBJECTIVE

Periodontal disease is one of the most prevalent oral diseases, which is associated with inflammation of the tooth-supporting tissues. Tormentic acid (TA), a triterpene isolated from Rosa rugosa, has been reported to exert anti-inflammatory effects. The aim of this study was to investigate the anti-inflammatory effects of TA on lipopolysaccharide (LPS)-stimulated human gingival fibroblasts (HGFs).

METHODS

The levels of inflammatory cytokines such as interleukin (IL)-6 and chemokines such as IL-8 were detected by enzyme-linked immunosorbent assay (ELISA). The expression of Toll-like receptor 4 (TLR4), nuclear factor kappa B (NF-κB), IκBα, p38, extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK) was determined by Western blotting.

RESULTS

The results showed that Porphyromonas gingivalis LPS significantly upregulated the expression of IL-6 and IL-8. TA inhibited the LPS-induced production of IL-6 and IL-8 in a dose-dependent manner. Furthermore, TA inhibited LPS-induced TLR4 expression; NF-κB activation; IκBα degradation; and phosphorylation of ERK, JNK, and P38.

CONCLUSION

TA inhibits the LPS-induced inflammatory response in HGFs by suppressing the TLR4-mediated NF-κB and mitogen-activated protein kinase (MAPK) signalling pathway.