The effect of adjunctive low-dose doxycycline therapy on clinical parameters and gingival crevicular fluid matrix metalloproteinase-8 levels in chronic periodontitis

Effects of Coriander on the Repair Process of Experimentally-induced Periodontitis in Rats

The aim of this study was to evaluate the effects of Coriandrum sativum L. (CSL) seed extract on gingival levels of antioxidant enzymes, pro-inflammatory cytokines and on alveolar bone and attachment levels after experimental periodontitis induction in rats and compare it with low-dose doxycycline (LDD). Forty adult male Wistar Albino rats were divided randomly into 5 groups as follows: 1 = periodontally healthy (control); 2 = periodontitis; 3 = periodontitis + CSL (32 mg/kg); 4 = periodontitis + CSL (200 mg/kg); and 5 = periodontitis + LDD (6 mg/kg). Gingival superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) levels were evaluated by enzyme-linked immunosorbent assay. The presence of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1βeta (IL-1β) immunoreactivity was detected immunohistochemically. Alveolar bone area in the furcation space (ABA), alveolar bone loss (ABL), and attachment loss (AL) were evaluated histomorphometrically. The SOD level was lower in group 5 than in groups 2, 3, and 4. The IL-1β level was highest in group 4. The TNF-α level was statistically higher in groups 2 and 4 than in groups 1, 3, and 5. The IL-6 level was highest in group 4. Its level was higher in groups 2 and 3 than in group 5. ABA was less in groups 2, 3, and 4 compared to groups 1 and 5. ABL was less in group 5 than in groups 2, 3, and 4. AL was greater in group 4 than in group 5. The use of 200 mg/kg CSL showed a pro-inflammatory effect and IL-1β and TNF-α levels decreased after 32 mg/kg CSL application in the treatment of periodontitis.

Importance of Metalloproteinase 8 (MMP-8) in the Diagnosis of Periodontitis

Periodontitis is a complex condition. Left untreated, it leads to tooth loss and the need for prosthetic treatment. The incidence of periodontitis is steadily increasing, so new methods are being sought to aid in the diagnosis of the disease. Among the methods postulated is the determination of concentrations of bioactive compounds which include extracellular matrix metalloproteinases (MMPs). These enzymes are present in various structural elements of the stomatognathic system. The most promising enzyme of this group appears to be metalloproteinase 8 (MMP-8). MMP-8 assays are performed in gingival fluid or saliva, and MMP-8 levels have been shown to be higher in patients with periodontitis compared to healthy subjects and correlated with some clinical parameters of the condition and the severity of the disease. In addition, the preliminary usefulness of this enzyme in evaluating the effectiveness of periodontal treatment and doxycycline therapy has been demonstrated. Determination of the active form of MMP-8 (aMMP-8) in oral rinse fluid using off-the-shelf assays shows the highest potential. Despite reports about aMMP-8 and promising data on the role of MMP-8 in periodontal diagnosis, a clear determination of the usefulness of this enzyme requires further research.

Matrix Metalloproteinases in Oral Health-Special Attention on MMP-8

Matrix metalloproteinases (MMPs) are a large family of Ca²⁺ and Zn²⁺ dependent proteolytic enzymes, able to cleave the various components of the extracellular matrix (ECM), as well as a range of other regulatory molecules. Several reports have proven the important role of both MMPs and their endogenous inhibitors, TIPMs, in oral health, the initial development of the tooth, and during enamel maturation. In this mini-review, we aim to summarize the literature information about the functions of MMPs, paying more attention to MMP-8 (collagenase-2 or neutrophil collagenase) in the development and progression of periodontitis, peri-implantitis, and carious lesions. We also emphasize the role of particular gene variants in MMP8 as predisposing factors for some oral diseases.

Controlled release devices as adjuvants in nonsurgical periodontal therapy: A systematic review

Controlled release devices (CRD) have been widely studied regarding their application in periodontal therapy. Therefore, the present study aims to evaluate the use and effectiveness of controlled-release devices in nonsurgical periodontal therapy through a systematic review. The research was carried out in six different databases, namely: Online Medical Literature Search and Analysis System (Medline-PubMed), Web of Science, Science Direct, Scopus, Scielo, and Google Scholar. The descriptors "Delayed-Action Preparation," "Therapeutics," and "Periodontitis," were used with their EntryTerms and connected through the Boolean operators AND and OR. A total of 2847 studies were found, and after applying the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist flowchart, 34 were selected using the eligibility criteria. After that, the qualitative results were tabulated and the risk of bias in each of them was evaluated. It can be observed that the use of CRD presents itself as a successful alternative for adjuvant treatment to periodontal therapy, a fact due to its availability and local concentration in the crevicular fluid. However, further clinical research is still needed to develop devices that are effective, with an easy and quick application, as well as available at a good cost-benefit ratio.

Comparative Evaluation of Gingival Crevicular Fluid Interleukin-17, 18 and 21 in Different Stages of Periodontal Health and Disease

Background and Objectives: The elicitation of a host’s immune−inflammatory responses to overcome oral bacterial biofilm challenges is mediated by numerous cytokines. We explored the role of three such cytokines, viz. interleukin (IL)-17, 18 and 21, by measuring their levels in the gingival crevicular fluid (GCF) of Indian individuals with healthy gingiva, chronic gingivitis, or chronic periodontitis. Materials and Method: Ninety systemically healthy individuals were enrolled in the study on the basis of predefined criteria and were categorized into three groups of 30 participants each. Groups A, B and C were composed of a control group with healthy gingiva, subjects with chronic gingivitis and subjects with chronic periodontitis, respectively. The periodontal disease status was assessed on the basis of a subject’s gingival index, probing pocket depth, clinical attachment loss and radiographic evidence of bone loss. After the complete history-taking and identification of gingival sulcus/pocket depth areas for GCF collection, a sample was collected from each subject in all groups for an estimation of the cytokine levels using ELISA. Statistical analysis was performed using SPSS v 21.0. Intergroup comparisons were conducted using a post hoc Tukey’s test. A value of p < 0.05 was considered to be statistically significant. Results: The mean IL-17, 18 and 21 concentrations in pg/mL was the greatest for Group C (99.67 ± 18.85, 144.61 ± 20.83 and 69.67 ± 12.46, respectively), followed by Group B (19.27 ± 2.78, 22.27 ± 2.43 and 22.74 ± 1.43, respectively) and finally by Group A (healthy control; 11.56 ± 0.99, 17.94 ± 1.24 and 12.83 ± 1.21 respectively). A statistically significant difference in the mean concentrations of two interleukins (IL-17 and IL-18) was observed between Groups A and C and also between Groups B and C. A statistically significant difference in the mean concentrations of IL-21 was observed between Groups B and C. Conclusions: Within the limitations of the present study, the findings revealed that the GCF levels of IL-17, IL-18 and IL-21 rose and correlated well with the severity of the disease. Thus, these cytokines present in GCF have the potential to be considered as biomarkers for periodontal tissue destruction. IL-21 in particular appears to be a promising biomarker for differentiating between gingivitis and periodontitis.

Preparation and quality by design assisted (Qb-d) optimization of bioceramic loaded microspheres for periodontal delivery of doxycycline hyclate

PLGA (Lactic- co-glycolic acid) coated chitosan microspheres loaded with hydroxyapatite and doxycycline hyclate complex were developed in the present study for periodontal delivery. A modified single emulsion method was adopted for the development of microspheres. Formulation was optimized on the basis of particle size, drug loading and encapsulation efficiency with the central composite design using 23 factorial design. Microspheres were optimized and electron microscopy revealed their spherical shape and porous nature. In-vitro study showed initial burst and then sustained release behavior of the formulation for 14 days. Further, in-vitro antibacterial study performed on E. coli (ATCC-25922) and S. aureus (ATCC-29213) revealed concentration dependent activity. Also, in-vitro cyto-toxicity assessment ensures biocompatibility of the formulation with the fibroblast's cells. Overall, the quality by design assisted PLGA microspheres, demonstrated the desired attributes and were found suitable for periodontal drug delivery.

Oral Administration of a Chemically Modified Curcumin, TRB-N0224, Reduced Inflammatory Cytokines and Cartilage Erosion in a Rabbit ACL Transection Injury Model

OBJECTIVE

To evaluate the effects of TRB-N0224, a chemically modified curcumin (CMC) with zinc binding properties and improved pharmacokinetics, in a rabbit anterior cruciate ligament (ACL) transection injury-induced model of osteoarthritis (OA).

DESIGN

Thirty-eight skeletally mature New Zealand white rabbits were studied in 4 groups: a sham with arthrotomy (n = 6), control with ACL transection (n = 6), and 2 treatment groups with ACL transection and administration of TRB-N0224 at low (25 mg/kg/day) (n = 13) and high (50 mg/kg/day) (n = 13) doses. After euthanization at 12 weeks, outcomes were measured by post-necropsy gross morphology, biomechanics, and cartilage and synovium histology. Rabbit blood ELISA quantified cytokine and matrix metalloproteinase (MMP) concentrations at 0, 4, 8, and 12 weeks.

RESULTS

Both treatment doses had fewer distal femoral condyle erosive defects than the control; the low dose demonstrated a mean 78% decrease (P < 0.01). Histologically, the low- and high-dose treatment groups had fewer cartilage pathologic changes and less severe synovitis than the control. CMC alone did not have a major effect on the biomechanics of healthy cartilage or cartilage in the ACL transection model, as demonstrated in 5 of the 6 measured properties/regions (P < 0.05). ELISA results suggested that the key mediators of OA, (interleukin) IL-1β, IL-6, TNFα (tumor necrosis factor-α), MMP-9, and MMP-13, had decreased concentrations with TRB-N0224 treatment at different time points between weeks 4 to 12 (P < 0.05).

CONCLUSIONS

In the pathogenesis of OA, an imbalance exists between catabolic and anabolic mediators. These results suggest the potential of TRB-N0224 to modulate MMP and cytokine levels, slowing the macroscopic and histopathological progression of OA.

The adjunctive use of host modulators in non-surgical periodontal therapy. A systematic review of randomized, placebo-controlled clinical studies

BACKGROUND

Considering the role of the inflammatory host response in the pathogenesis of periodontitis, different host modulators have been proposed to enhance the outcomes of non-surgical periodontal therapy (NSPT), but their efficacy has not been fully clarified.

OBJECTIVES

This systematic review investigated the efficacy of host modulators combined with NSPT in reducing probing pocket depth (PPD) in periodontitis patients.

MATERIALS AND METHODS

Placebo-controlled RCTs with ≥6 months follow-up were searched. Meta-analysis was conducted when ≥5 studies using the same host modulator were identified.

RESULTS

Fifty eight studies met the inclusion criteria. After 6 months, local administration of 1.2% statin gels as adjuncts to NSPT significantly improved PPD reduction (1.83 mm) in infrabony defects and systemic administration of sub-antimicrobial dose doxycycline (SDD) in addition to NSPT improved PPD reduction of deep pockets. Administration of probiotics conferred limited clinical benefits. Local bisphosphonate and metformin gels showed potential for clinical use in infrabony defects, which needs to be confirmed.

CONCLUSIONS

Local delivery of statins in infrabony defects and systemic SDD for deep pockets may confer additional clinical benefits to NSPT. Their long-term effectiveness and safety need to be confirmed in independent multi-centred studies. Further studies are needed to confirm the benefit of other host modulators.

Localized probiotic-guided pocket recolonization in the treatment of chronic periodontitis: a randomized controlled clinical trial

Purpose

This randomized clinical placebo-controlled trial was conducted to evaluate the effectiveness of Lactobacillus reuteri as a probiotic in guided pocket recolonization (GPR) for the treatment of chronic periodontitis (CP) adjunctive to scaling and root planing (SRP).

Methods

Forty-eight CP patients were randomly assigned to 3 treatment groups: group 1 (SRP+placebo), group 2 (SRP+single application of probiotic), and group 3 (SRP+incremental application of probiotic). Clinical parameters were evaluated at baseline and at 8, 12, and 24 weeks, whereas biochemical parameters were measured at baseline and 12 weeks.

Results

At 24 weeks, the probing pocket depth and clinical attachment level improved in all 3 groups from baseline with no significant intergroup differences; however, a statistically significant difference was observed in localized plaque and gingival scores between groups 1 and 3 (P<0.05). At 12 weeks, matrix metalloproteinase-8 (MMP-8), nitric oxide (NO), and gingipains-R (Rgps) levels improved in all 3 groups, with statistically significant differences between groups 1 and 3 for MMP-8 and NO (P<0.05), but no difference for Rgps levels.

Conclusions

Within its limitations, the results of this study show that incremental 3-time application of L. reuteri as a probiotic led to improvements in clinical and biochemical parameters. This protocol can be a useful adjunct to SRP in the non-surgical management of CP.

Trial Registration

Clinical Trials Registry - India Identifier: CTRI/2017/03/008231

Design and in vitro/in vivo evaluations of a multiple-drug-containing gingiva disc for periodontotherapy

In the current work, we set out to develop and evaluate a gingiva disc of cellulose acetate phthalate and poloxamer F-127 for the simultaneous delivery of multiple drugs, namely minocycline, celecoxib, doxycycline hyclate, and simvastatin, to abolish infection, impede inflammation, avert collagen destruction, and promote alveolar bone regeneration, respectively. In vitro release studies revealed the sustained release profiles of the drugs for 12 h and that they were active against Staphylococcus aureus, Escherichia coli and Streptococcus mutans. The in vivo bioactivity levels of these drugs were assessed by comparing the number of colony forming units during different phases of a study on Wistar rats, and the results showed a reduction in the number of bacterial colonies with the applied formulation. A mucosal irritation study conducted on Wistar rat gingiva confirmed the non-irritancy of the optimal gingiva disc. Hence, this customized, non-invasive polymeric gingiva disc displaying a sustained release of drugs can be a useful tool to treat acute to moderate stages of periodontitis.

Macrophage immunomodulation in chronic osteolytic diseases-the case of periodontitis

Periodontitis (PD) is a chronic osteolytic disease that shares pathogenic inflammatory features with other conditions associated with nonresolving inflammation. A hallmark of PD is inflammation-mediated alveolar bone loss. Myeloid cells, in particular polymorphonuclear neutrophils (PMN) and macrophages (Mac), are essential players in PD by control of gingival biofilm pathogenicity, activation of adaptive immunity, as well as nonresolving inflammation and collateral tissue damage. Despite mounting evidence of significant innate immune implications to PD progression and healing after therapy, myeloid cell markers and targets for immune modulation have not been validated for clinical use. The remarkable plasticity of monocytes/Mac in response to local activation factors enables these cells to play central roles in inflammation and restoration of tissue homeostasis and provides opportunities for biomarker and therapeutic target discovery for management of chronic inflammatory conditions, including osteolytic diseases such as PD and arthritis. Along a wide spectrum of activation states ranging from proinflammatory to pro-resolving, Macs respond to environmental changes in a site-specific manner in virtually all tissues. This review summarizes the existing evidence on Mac immunomodulation therapies for osteolytic diseases in the broader context of conditions associated with nonresolving inflammation, and discusses osteoimmune implications of Macs in PD.

Adjunctive Effects of a Sub-Antimicrobial Dose of Doxycycline on Clinical Parameters and Potential Biomarkers of Periodontal Tissue Catabolism

Objectives: The aim of the present randomized, double-blind, placebo-controlled, parallel-arm study was to examine the effectiveness of a sub-antimicrobial dose of doxycycline (SDD) in combination with nonsurgical periodontal therapy, compared to nonsurgical periodontal therapy alone, on potential gingival crevicular fluid (GCF) biomarkers of periodontal tissue catabolism related to the clinical outcomes over a 12-month period. Materials and Methods: GCF was collected and clinical parameters were recorded from 30 periodontitis patients randomized either to an SDD or placebo group. The SDD group received SDD (20 mg) b.i.d for 3 months plus scaling and root planing (SRP), while the placebo group was given placebo capsules b.i.d for 3 months plus SRP. The patients were evaluated every 3 months during the 12-month study period. At each visit, clinical parameters and GCF sampling were repeated. Matrix metalloproteinase (MMP)-8, MMP-9, MMP-13, myeloperoxidase (MPO), osteoprotegerin (OPG), and tartrate-resistant acid phosphatase-5 (TRAP-5) were determined by IFMA and ELISA. Results: Significant improvements were observed in all clinical parameters in both groups over 12 months (p < 0.0125) while the SDD group showed significantly better reduction in gingival index (GI) and pocket depth and a gain in clinical attachment compared to the placebo group (p < 0.05). GCF MMP-8 and OPG levels significantly reduced in the SDD group compared to baseline (p < 0.05). GCF MMP-9 significantly decreased in both groups compared to baseline (p < 0.05). GCF MPO significantly decreased at 3 and 9 months in the SDD group, while it significantly decreased at 6 months in the placebo group (p < 0.05). TRAP and MMP-13 could be detected in none of the samples. Conclusions: The present results indicate that three months of adjunctive usage of SDD to nonsurgical periodontal therapy compared to nonsurgical periodontal therapy alone in periodontitis patients results in further improvement of clinical periodontal parameters and GCF markers of periodontal tissue breakdown over a 12-month period. Beneficial effects of adjunctive SDD therapy is likely to be related to the reduced levels of two major periodontitis-associated MMPs, MMP-8 and -9, and their potential oxidative activator MPO.

Matrix Metalloproteinase-8 as an Inflammatory and Prevention Biomarker in Periodontal and Peri-Implant Diseases

Levels of and especially the degree of activation of matrix metalloproteinase (MMP-8) in oral fluids (i.e., saliva, mouth rinse, gingival crevicular fluid (GCF) and peri-implantitis sulcular fluid (PISF)) increase to pathologically elevated levels in the periodontal and peri-implant diseases. This study aimed at collecting and collating data from previously published studies and determining whether active MMP-8 (aMMP-8) could serve as a biomarker for the diagnosis and prevention of periodontal and peri-implant diseases. The literature search identified a total of 284 articles. Out of 284 articles, 61 articles were found to be relevant. Data obtained from the selected studies were combined, and it indicated that aMMP-8 in oral fluids exerts the strong potential to serve as a useful adjunctive diagnostic and preventive biotechnological tool in periodontal and peri-implant diseases. aMMP-8 can be used alone or in combination with other proinflammatory and/or microbiological biomarkers.

Emerging Therapies for Acne Vulgaris

As we gain a greater understanding of acne pathogenesis, both new agents as well as new uses for established drugs are being considered for the treatment of acne vulgaris. Multiple clinical trials assessing new formulations or combinations of established acne treatments have been conducted, and novel uses of antimicrobials such as modified diallyl disulfide oxide and nitric oxide are being assessed in clinical trials. There are also a multitude of new therapies currently being studied that target the inflammatory cascade of acne pathogenesis, including sebosuppressive and anti-inflammatory phytochemicals, and  small molecule inhibitors targeting sebaceous glands and enzymes, among others. Laser and light therapy is also being modified for the treatment of acne through combination methods with metal nanoshells and vacuum assistance. Probiotics have gained popularity in medicine as greater knowledge of the microbiome and its effects on multiple organ systems is being elucidated. Studies describing the positive effects of certain ammonia-oxidizing bacterial strains in the regulation of the skin's inflammatory response are ongoing. Therapies for acne are constantly evolving and current gold-standard acne therapy may be supplemented with novel treatment modalities in the near future.

Commentary: Targeting Underlying Biologic Mechanisms in Selecting Adjunctive Therapies to Improve Periodontal Treatment in Smokers: A Commentary

Despite well-established evidence that cigarette smoking is the largest modifiable risk factor for periodontal disease and has many deleterious health effects, treatment of periodontal disease in smokers remains a challenge of periodontal therapy. A recent meta-analysis revealed that adjunctive use of local delivery of antimicrobials, but not systemic antibiotic usage, with non-surgical periodontal therapy resulted in improvement in clinical periodontal parameters. Further evaluation of the current literature reveals that host modulation therapy may also result in clinical benefit in smokers. These findings may be tied to the underlying pathophysiology of periodontal disease progression in smokers and suggest that focused therapies that target known mechanisms of action are critical to the success of proposed treatments.

Effects of avocado/soybean unsaponifiables (ASU) on the treatment of ligature-induced periodontitis in rats

The purpose of this study is to evaluate the effect of the avocado/soybean unsaponifiables (ASU) on the treatment of induced periodontitis in rats. Periodontitis was induced in 84 rats via ligature placement around the second upper molar, which was removed after 7 days, and scaling and root planning (SRP) was performed at this time. Subsequently, the rats were randomly allocated to four groups with 21 animals each: One SRP group in which saline solution was administered (SS), and three groups in which ASU was administered (0.6 g/kg/day), beginning either 7 days before the induction of periodontitis (SRP/ASU-7), on the day of periodontitis induction (SRP/ASU0), or on the day of treatment (SRP/ASU+7). ASU and SS were administered daily by gavage until the sacrifice of the animals (7, 15, and 30 days after SRP). The % bone in the furcation area was evaluated by histomorphometry and micro-CT. The expression of proteins (TRAP, RANKL, and alkaline phosphatase) and mRNA (IL-1β, TNF-α, IL-6, RANKL, and alkaline phosphatase) were evaluated by immunohistochemistry and qPCR. The SRP/ASU+7 group presented a higher percentage of bone fill in the furcation area and higher expression of alkaline phosphatase than in the SRP group (at 7 and 30 days, respectively). The SRP/ASU0 and SRP/ASU+7 groups presented lower expression levels of RANKL mRNA than the SRP and SRP/ASU-7 groups at 15 days. ASU administration on the day of the SRP treatment of the ligature-induced periodontitis promoted subtle beneficial effects on periodontal repair following the treatment of induced periodontitis within the experimental period of 7 days.

Systematic review and meta-analysis on the nonsurgical treatment of chronic periodontitis by means of scaling and root planing with or without adjuncts

BACKGROUND

Conduct a systematic review and meta-analysis on nonsurgical treatment of patients with chronic periodontitis by means of scaling and root planing (SRP) with or without adjuncts.

METHODS

A panel of experts convened by the American Dental Association Council on Scientific Affairs conducted a search of PubMed (MEDLINE) and Embase for randomized controlled trials of SRP with or without the use of adjuncts with clinical attachment level (CAL) outcomes in trials at least 6 months in duration and published in English through July 2014. The authors assessed individual study bias by using the Cochrane Risk of Bias Tool and conducted meta-analyses to obtain the summary effect estimates and their precision and to assess heterogeneity. The authors used funnel plots and Egger tests to assess publication bias when there were more than 10 studies. The authors used a modified version of the US Preventive Services Task Force methods to assess the overall level of certainty in the evidence.

RESULTS

The panel included 72 articles on the effectiveness of SRP with or without the following: systemic antimicrobials, a systemic host modulator (subantimicrobial-dose doxycycline), locally delivered antimicrobials (chlorhexidine chips, doxycycline hyclate gel, and minocycline microspheres), and a variety of nonsurgical lasers (photodynamic therapy with a diode laser, a diode laser, neodymium:yttrium-aluminum-garnet lasers, and erbium lasers).

CONCLUSIONS AND PRACTICAL IMPLICATIONS

With a moderate level of certainty, the panel found approximately a 0.5-millimeter average improvement in CAL with SRP. Combinations of SRP with assorted adjuncts resulted in a range of average CAL improvements between 0.2 and 0.6 mm over SRP alone. The panel judged the following 4 adjunctive therapies as beneficial with a moderate level of certainty: systemic subantimicrobial-dose doxycycline, systemic antimicrobials, chlorhexidine chips, and photodynamic therapy with a diode laser. There was a low level of certainty in the benefits of the other included adjunctive therapies. The panel provides clinical recommendations in the associated clinical practice guideline.

Multidimensional Contribution of Matrix Metalloproteinases to Atherosclerotic Plaque Vulnerability: Multiple Mechanisms of Inhibition to Promote Stability

The prevalence of atherosclerotic disease continues to increase, and despite significant reductions in major cardiovascular events with current medical interventions, an additional therapeutic window exists. Atherosclerotic plaque growth is a complex integration of cholesterol penetration, inflammatory cell infiltration, vascular smooth muscle cell (VSMC) migration, and neovascular invasion. A family of matrix-degrading proteases, the matrix metalloproteinases (MMPs), contributes to all phases of vascular remodeling. The contribution of specific MMPs to endothelial cell integrity and VSMC migration in atherosclerotic lesion initiation and progression has been confirmed by the increased expression of these proteases in plasma and plaque specimens. Endogenous blockade of MMPs by the tissue inhibitors of metalloproteinases (TIMPs) may attenuate proteolysis in some regions, but the progression of matrix degeneration suggests that MMPs predominate in atherosclerotic plaque, precipitating vulnerability. Plaque neovascularization also contributes to instability and, coupling the known role of MMPs in angiogenesis to that of atherosclerotic plaque growth, interest in targeting MMPs to facilitate plaque stabilization continues to accumulate. This article aims to review the contributions of MMPs and TIMPs to atherosclerotic plaque expansion, neovascularization, and rupture vulnerability with an interest in promoting targeted therapies to improve plaque stabilization and decrease the risk of major cardiovascular events.

Ligand-induced expansion of the S1' site in the anthrax toxin lethal factor

The Bacillus anthracis lethal factor (LF) is one component of a tripartite exotoxin partly responsible for persistent anthrax cytotoxicity after initial bacterial infection. Inhibitors of the zinc metalloproteinase have been investigated as potential therapeutic agents, but LF is a challenging target because inhibitors lack sufficient selectivity or possess poor pharmaceutical properties. These structural studies reveal an alternate conformation of the enzyme, induced upon binding of specific inhibitors, that opens a previously unobserved deep pocket termed S1'(∗) which might afford new opportunities to design selective inhibitors that target this subsite.

Doxycycline-encapsulated nanotube-modified dentin adhesives

This article presents details of fabrication, biological activity (i.e., anti-matrix metalloproteinase [anti-MMP] inhibition), cytocompatibility, and bonding characteristics to dentin of a unique doxycycline (DOX)-encapsulated halloysite nanotube (HNT)-modified adhesive. We tested the hypothesis that the release of DOX from the DOX-encapsulated nanotube-modified adhesive can effectively inhibit MMP activity. We incorporated nanotubes, encapsulated or not with DOX, into the adhesive resin of a commercially available bonding system (Scotchbond Multi-Purpose [SBMP]). The following groups were tested: unmodified SBMP (control), SBMP with nanotubes (HNT), and DOX-encapsulated nanotube-modified adhesive (HNT+DOX). Changes in degree of conversion (DC) and microtensile bond strength were evaluated. Cytotoxicity was examined on human dental pulp stem cells (hDPSCs). To prove the successful encapsulation of DOX within the adhesives-but, more important, to support the hypothesis that the HNT+DOX adhesive would release DOX at subantimicrobial levels-we tested the antimicrobial activity of synthesized adhesives and the DOX-containing eluates against Streptococcus mutans through agar diffusion assays. Anti-MMP properties were assessed via β-casein cleavage assays. Increasing curing times (10, 20, 40 sec) led to increased DC values. There were no statistically significant differences (p > .05) in DC within each increasing curing time between the modified adhesives compared to SBMP. No statistically significant differences in microtensile bond strength were noted. None of the adhesives eluates were cytotoxic to the human dental pulp stem cells. A significant growth inhibition of S. mutans by direct contact illustrates successful encapsulation of DOX into the experimental adhesive. More important, DOX-containing eluates promoted inhibition of MMP-1 activity when compared to the control. Collectively, our findings provide a solid background for further testing of encapsulated MMP inhibitors into the synthesis of therapeutic adhesives that may enhance the longevity of hybrid layers and the overall clinical performance of adhesively bonded resin composite restorations.

Non-surgical periodontal therapy with systemic antibiotics in patients with untreated chronic periodontitis: a systematic review and meta-analysis

OBJECTIVE

The purpose of this meta-analysis is to evaluate the effectiveness of different systemic antibiotics in combination with scaling and root planing (SRP) when compared to SRP alone in patients with untreated chronic periodontitis.

BACKGROUND

Although chronic periodontitis is mostly treated without adjunctive systemic antibiotics, some recent meta-analyses have shown clinical benefit for some systemic antibiotics when used as an adjunct to SRP. However, there is a wide variety of systemic antibiotic regimens used today. It remains unclear if the selected type of systemic antibiotic influences the magnitude of clinical benefit.

MATERIAL AND METHODS

The MEDLINE-PubMed database was searched from their earliest records through May 16, 2013. Several journals were hand searched and some authors were contacted for additional information. Outcome measures analysed were mean bleeding on probing change, mean clinical attachment level gain and mean probing pocket depth reduction. Extracted data were pooled using a random effect model. Weighted mean differences were calculated and heterogeneity was assessed.

RESULTS

The search yielded 281 abstracts. Ultimately, 95 studies were selected, describing 43 studies meeting the eligibility criteria. Systemic antibiotics showed a significant (p < 0.05) additional pocket depth reduction for moderate (at 3 mo 0.27 mm ± 0.09, at 6 mo 0.23 mm ± 0.10 and at 12 mo 0.25 mm ± 0.27) and deep pockets (at 3 mo 0.62 mm ± 0.17, at 6 mo 0.58 mm ± 0.16 and at 12 mo 0.74 mm ± 0.30). Statistically, no specific type of antibiotic was superior over another. However, when analysing the clinical data for initially moderate pockets or deep pockets, some trends became apparent.

CONCLUSION

Systemic antibiotics combined with SRP offer additional clinical improvements compared to SRP alone. Although there were no statistically significant differences, there was a trend that for initially moderate and deep pockets, metronidazole or metronidazole combined with amoxicillin, resulted in clinical improvements that were more pronounced over doxycycline or azithromycin. Additionally, there was a trend that the magnitude of the clinical benefit became smaller over time (1 year).

[Doxycycline or how to create new with the old?]

Tetracyclines are broad-spectrum antibiotics that interfere with protein synthesis. They were first widely prescribed by dermatologists in the early 1950s in the treatment of acne. More recently, their biological actions on inflammation, proteolysis, angiogenesis, apoptosis, metal chelation, ionophoresis, and bone metabolism were studied. Matrix metalloproteinases (MMPs) are a family of proteolytic enzymes that degrade components of the extracellular matrix (ECM). MMPs have direct or indirect effects on the vascular endothelium and the vascular relaxation/contraction system. The therapeutic effects of tetracyclines and analogues were studied in rosacea, bullous dermatoses, neutrophilic diseases, pyoderma gangrenosum, sarcoidosis, aortic aneurysms, cancer metastasis, periodontitis and autoimmune diseases autoimmune diseases such as rheumatoid arthritis and scleroderma. In addition, downregulation of MMP using doxycycline could be beneficial in reducing vascular dysfunction mediated by MMPs and progressive damage of the vascular wall. We review the nonantibiotic properties of doxycycline and its potential clinical applications.

Diagnosis and anti-infective therapy of periodontitis

Periodontal diseases (gingivitis and periodontitis) are chronic bacterial infections with a remarkably high prevalence and morbidity. Periodontitis, in contrast to gingivitis, is not reversible, is associated with certain bacterial species and affects all of the soft tissue and bone that support teeth. Among the periodontal pathogens, species, such as Aggregatibacter (Actinobacillus) actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythensis, and several forms of uncultivable spirochetes play the major role in the pathogenesis. In severe chronic, recurrent and especially aggressive forms of periodontitis, diagnosis of the species involved and, whenever possible, an optimized evidence-based antimicrobial treatment is indicated. In order to monitor alarming bacterial changes in the periodontal pocket, several techniques, namely microscopy, culture, immunoassays, enzyme tests and DNA-based techniques, have been established and the methods are described in the first part of this review. In the second part, the selection and use of locally delivered (topical) and systemic antibiotics used adjunctively in periodontal therapy are discussed.

Metalloproteases and tendinopathy

Matrix metalloproteinases (MMP) are involved in the development of tendinopathy. These potent enzymes completely degrade all components of the connective tissue, modify the extracellular matrix (ECM), and mediate the development of painful tendinopathy. To control the local activity of activated proteinases, the same cells produce tissue inhibitors of metalloproteinases (TIMP). These latter bind to the enzyme and prevent degradation. The balance between the activities of MMPs and TIMPs regulates tendon remodeling, whereas an imbalance produces a collagen dis-regulation and disturbances in tendons. ADAMs (a disintegrin and metalloproteinase) are cell membrane-linked enzymes with proteolytic and cell signaling functions. ADAMTSs (ADAM with thrombospondin motifs) are secreted into the circulation and constitute a heterogenous family of proteases with both anabolic and catabolic functions. Further studies are needed to better define the mechanism of action, and whether these new strategies are safe and effective in larger models.

Efficacy of short-term adjunctive subantimicrobial dose doxycycline in diabetic patients--randomized study

OBJECTIVE

To investigate the effectiveness of short-term adjunctive subantimicrobial dose doxycycline (SDD) treatment in patients with diabetes mellitus type 2 and chronic periodontitis (CP).

METHODS

Thirty-four patients with CP and type 2 diabetes mellitus were included in the placebo-controlled, double-blind study. After scaling and root planing (SRP), patients were randomly assigned to two groups, receiving either SDD or placebo bid for 3 months. The probing depth (PD), clinical attachment level (CAL), bleeding on probing (BOP), approximal plaque index, glycated hemoglobin (HbA1c) level were recorded and gingival crevicular fluid (GCF) samples were collected at baseline and after 3-month therapy for the estimation of matrix metalloproteinase-8 levels.

RESULTS

Clinical attachment level, PD, and BOP improved significantly in both groups after therapy (P < 0.05). The statistically significant difference between the two groups after the therapy was observed only in PD in tooth sites with initial PD ≥ 4 mm (SRP + placebo: 3.41 ± 0.6 mm vs SRP + SDD: 2.92 ± 0.5 mm, P < 0.05). GCF matrix metalloproteinase-8 levels were significantly reduced only in SRP + SDD group (P < 0.01). There were no changes in HbA1c levels after therapy.

CONCLUSION

The short-term administration of SDD gives significant benefit at tooth sites with moderate disease (PD ≥ 4 mm) when compared to SRP alone in patients with diabetes and CP.

Multilevel analysis of clinical parameters in chronic periodontitis after root planing/scaling, surgery, and systemic and local antibiotics: 2-year results

AIM

Find the periodontal treatment that best maintained clinical results over time evaluated by changes in pocket depth (PD) and clinical attachment level (CAL).

METHODS

229 patients with chronic periodontitis from USA (n=134) and Sweden (n=95) were randomly assigned to eight groups receiving (1) scaling+root planing (SRP) alone or combined with (2) surgery (SURG)+systemic amoxicillin (AMOX)+systemic metronidazole (MET); (3) SURG+local tetracycline (TET); (4) SURG; (5) AMOX+MET+TET; (6) AMOX+MET; (7) TET; and (8) SURG+AMOX+MET+TET. Antibiotics were given immediately after SRP. Plaque, gingival redness, bleeding on probing, suppuration, PD, and CAL were recorded at baseline and after 3, 6, 12, 18, and 24 months. Treatment effects were evaluated by linear multilevel regression and logistic multilevel regression models. We considered only data from sites with a baseline PD of at least 5 mm of 187 patients completing the study.

RESULTS

Surgically treated patients experienced most CAL loss. Adjunctive therapy including SURG was most effective in reducing PD. Combining SURG with AMOX, MET, and TET gave significant clinical benefits. Past and current smoking habits were significant predictors of deeper PD. Only current smoking was a significant predictor of CAL loss. Bleeding, accumulation of plaque, gingival redness, and suppuration were significant predictors of further CAL loss and deeper PD.

CONCLUSIONS

Both surgical and non-surgical therapies can be used to arrest chronic periodontitis. SURG+AMOX+MET+TET gave best maintenance of clinical results.

Control of periodontal infections: a randomized controlled trial I. The primary outcome attachment gain and pocket depth reduction at treated sites

OBJECTIVE

To compare the treatment outcome of scaling and root planing (SRP) in combination with systemic antibiotics, local antibiotic therapy and/or periodontal surgery.

MATERIAL AND METHODS

One hundred and eighty-seven patients were assigned to eight groups treated by SRP plus none, one, two or three adjunctive treatments and monitored for 24 months in a randomized controlled clinical trial using a 2 × 2 × 2 factorial design. Systemic amoxicillin + metronidazole (SMA), local tetracycline delivery (LTC) and periodontal surgery (SURG) were evaluated as adjuncts. Changes in clinical attachment level (CAL) and probing pocket depth (PPD) were statistically evaluated by ancova of main effects.

RESULTS

Effects of adjunctive therapy to SRP were minimal at 3 months. Between 3 and 6 months PPD reduction occurred particularly in patients receiving periodontal surgery. After 6 months, both CAL gain and PPD reduction reached a plateau that was maintained at 24 months in all groups. The 24-month CAL gain was improved by SMA (0.50 mm) while PPD was reduced by SMA (0.51 mm) and SURG (0.36 mm). Smoking reduced CAL gain and PPD reduction.

CONCLUSION

Patients receiving adjunctive therapies generally exhibited improved CAL gain and/or PPD reduction when compared with the outcome of SRP alone. Only additive, not synergistic effects of the various adjunctive therapies were observed.

Metalloproteases and rotator cuff disease

The molecular changes occurring in rotator cuff tears are still unknown, but much attention has been paid to better understand the role of matrix metalloproteinases (MMP) in the development of tendinopathy. These are potent enzymes that, once activated, can completely degrade all components of the connective tissue, modify the extracellular matrix (ECM), and mediatethe development of painful tendinopathy and tendon rupture. To control the local activity of activated proteinases, the same cells produce tissue inhibitors of metalloproteinases (TIMP) that bind to the enzymes and prevent degradation. The balance between the activities of MMPs and TIMPs regulates tendon remodeling, whereas an imbalance produces a collagen dis-regulation and disturbances intendons. ADAMs (a disintegrin and metalloproteinase) are cell membrane-linked enzymes with proteolytic and cell signaling functions. ADAMTSs (ADAM with thrombospondin motifs) are secreted into the circulation, and constitute a heterogenous family of proteases with both anabolic and catabolic functions. Biologic modulation of endogenous MMP activity to basal levels may reduce pathologic tissue degradation and favorably influence healing after rotator cuff repair. Further studies are needed to better define the mechanism of action, and whether these new strategies are safe and effective in larger models.

Effects of periodontal therapy on GCF cytokines in generalized aggressive periodontitis subjects

AIM

To examine changes in levels of gingival crevicular fluid (GCF) cytokines, after periodontal therapy of generalized aggressive periodontitis (GAgP).

MATERIALS AND METHODS

Twenty-five periodontally healthy and 24 GAgP subjects had periodontal clinical parameters measured and gingival crevicular fluid (GCF) samples collected from up to 14 sites/subject. GCF samples were analysed using multiplex bead immunoassay for: GM-CSF, IFN-γ, IL-10, IL-1β, IL-2, IL-6 and TNF-α. Aggressive periodontitis subjects were randomly assigned to either scaling and root planing (SRP) alone or SRP plus systemic amoxicillin (500 mg) and metronidazole (400 mg) 3 times a day for 14 days. Clinical parameters and GCF cytokines were re-measured 6 months after treatment. Differences over time were analysed using the Wilcoxon test and between groups using the Mann-Whitney test.

RESULTS

Significant reductions in GCF GM-CSF, IL-1β and the ratio IL-1β/IL-10 and increases in GCF IL-6 were detected after therapy. The mean change in GCF cytokines did not differ significantly between groups.

CONCLUSIONS

Periodontal therapy improved GCF cytokine profiles by lowering IL-1β and increasing IL-10 levels. The reduction in GCF GM-CSF after therapy implicates this cytokine in the pathogenesis of GAgP. There was no difference between therapies in changes of GCF cytokines.

Full-mouth profile of active MMP-8 in periodontitis patients

BACKGROUND AND OBJECTIVE

MMP-8 in gingival crevicular fluid is considered as a protease with high destructive potential because of its ability to degrade collagen in periodontitis-affected patients. The aim of this study was to investigate whether there was a relationship between clinical diagnostic parameters and the concentration of active MMP-8 (aMMP-8) in gingival crevicular fluid in a site-level full-mouth analysis. Based on these data, the prognostic value of aMMP-8 levels in relation to pocket depth may be evaluated.

MATERIAL AND METHODS

Clinical measurements of pocket depth, bleeding on probing (BOP), plaque index (PlI) and gingival index (GI), as well as samples of gingival crevicular fluid, were obtained from four sites of each tooth of nine healthy female patients with chronic generalized periodontitis. The aMMP-8 concentration in gingival crevicular fluid was quantified by ELISA using specific monoclonal antibodies. Multiple linear regression models for the single measures of aMMP-8 and pocket depth were calculated with GI and BOP as additional variables.

RESULTS

Between 92 and 112 recordings were obtained for each parameter in each patient. Mean values of between 31.5 and 88.8% were calculated for pocket depths of ≥ 4 mm. Mean pocket depths ranged from 3.11 to 4.73 mm, the mean BOP values ranged from 34.0 to 96.7% and the mean full-mouth gingival crevicular fluid aMMP-8 concentration ranged from 3.2 to 23.7 ng/mL.

CONCLUSION

In this sample of female periodontitis patients, a broad range of intra-individual and interindividual aMMP-8 values was found. Although the explained variance was rather weak, a statistically significant relationship between aMMP-8 and pocket depth was proven.

Platform switching and matrix metalloproteinase-8 levels in peri-implant sulcular fluid

OBJECTIVES

The concept of platform switching has been introduced to implant therapy, however long-term data are sparse. The aim of this study was to biochemically investigate the inflammatory response mediated by MMP-8 to platform switching after 3 years of loading, in order to understand the long-term effect of implant/abutment mismatching on peri-implant health.

METHODS

A total of 70 implants had been inserted in the posterior maxilla in 26 patients and were randomly assigned to one of the four treatment regimens (implant diameter 3.8 [control group], 4.3 [Test group 1, T(1)], 4.8 [Test group 2, T(2)] and 5.5 mm [Test group 3, T(3)]). All implants were restored using a 3.8 mm abutment. In the test groups, this restoration resulted in a mismatching of 0.25-0.85 mm of implant-abutment diameters.

RESULTS

Thirty-six months after prosthetic rehabilitation, peri-implant sulcular fluid samples were taken from two aspects of all implants and from periodontally healthy adjacent teeth. Samples were processed in a conventional ELISA using monoclonal antibodies recognizing the active entity of MMP-8. In the test groups, MMP-8 mean values were 2.76 ng for T(1) (SD: 2.91), 3.30 ng for T(2) (SD: 1.94) and 3.18 ng for T(3) (SD: 2.46). For the control group, MMP-8 mean value was 3.6 ng (SD: 2.23), whereas 3.38 ng (SD: 2.2) was recorded at the adjacent teeth. There were no statistically significant differences in MMP-8 values between the groups (P=0.113, Kruskal-Wallis).

CONCLUSIONS

The presence of an implant/abutment mismatching specific for this prosthetic concept is compatible with long-term peri-implant health as demonstrated by analysis of a sensitive biomarker of the peri-implant inflammatory response.

Long-term efficacy of subantimicrobial-dose doxycycline as an adjunctive treatment to scaling and root planing: a systematic review and meta-analysis

BACKGROUND

Subantimicrobial-dose doxycycline (SDD) is widely used as an adjunctive treatment to scaling and root planing (SRP), but its long-term effectiveness remains controversial. The purpose of this systematic review was to assess the actual evidence of the effectiveness of SRP + SDD compared to SRP + placebo in the treatment of chronic periodontitis.

METHODS

A literature search of electronic databases was performed for articles published through November 1, 2010. Several dental journals were screened during the manual search, and authors were contacted for missing information. The systematic review and meta-analysis were conducted according to the Quality of Reporting of Meta-Analyses statement and recommendations of the Cochrane Collaboration. The methodologic quality of the studies was determined via a Consolidated Standards of Reporting Trials-based assessment. Clinical attachment levels, probing depths, plaque and gingival indices, and gingival crevicular fluid levels were compared between baseline and the end of follow-up. Data were extracted and pooled using a random-effect model. The weighted mean difference was reported with the 95% confidence interval. Heterogeneity was assessed using the χ(2)-based Q-statistic method and I(2) measurement. P <0.05 was considered statistically significant.

RESULTS

After applying inclusion and exclusion criteria, three randomized placebo-controlled clinical trials were entered into the meta-analysis. These studies had similar treatment designs, SDD dosage regimens (20 mg twice daily for 3 months), and post-treatment follow-up lengths (9 months). Significant differences were observed for all investigated clinical parameters in favor of the SRP + SDD group.

CONCLUSION

The meta-analysis results seemed to support the long-term effectiveness of adjunctive SDD therapy; however, future studies are needed to confirm these findings.

Matrix metalloproteinase8 has a central role in inflammatory disorders and cancer progression

The predominant role of matrix metalloproteinase 8 in extracellular matrix turnover, modulation of inflammatory responses and other physiological processes is well documented. Several recent studies highlight the involvement of MMP8 in a wide range of pathologies. This review will shed light on the putative role of MMP8 as a drug target or disease marker in some inflammatory disorders and in cancer progression.