Periodontal host modulation with antiproteinase, anti-inflammatory, and bone-sparing agents. A systematic review

β-Glucans (Saccharomyces cereviseae) Reduce Glucose Levels and Attenuate Alveolar Bone Loss in Diabetic Rats with Periodontal Disease

The objective of this study was to assess the effects of oral ingestion of β-glucans isolated from Saccharomyces cereviseae on the metabolic profile, expression of gingival inflammatory markers and amount of alveolar bone loss in diabetic rats with periodontal disease. Diabetes mellitus was induced in 48 Wistar rats by intraperitoneal injection of streptozotocin (80 mg/kg). After confirming the diabetes diagnosis, the animals were treated with β-glucans (by gavage) for 28 days. On the 14^th day of this period, periodontal disease was induced using a ligature protocol. β-glucans reduced the amount of alveolar bone loss in animals with periodontal disease in both the diabetic and non-diabetic groups (p < 0.05). β-glucans reduced blood glucose, cholesterol and triacylglycerol levels in diabetic animals, both with and without periodontal disease (p < 0.05). Furthermore, treatment with β-glucans reduced the expression of cyclooxygenase-2 and receptor activator of nuclear factor kappa-B ligand and increased osteoprotegerin expression in animals with diabetes and periodontal disease (p < 0.05). It was concluded that treatment with β-glucans has beneficial metabolic and periodontal effects in diabetic rats with periodontal disease.

Novel insight into drug repositioning: Methylthiouracil as a case in point

Drug repositioning refers to the development of existing drugs for new indications. These drugs may have (I) failed to show efficacy in late stage clinical trials without safety issues; (II) stalled in the development for commercial reasons; (III) passed the point of patent expiry; or (IV) are being explored in new geographic markets. Over the past decade, pressure on the pharmaceutical industry caused by the 'innovation gap' owing to rising development costs and stagnant product output have become major reasons for the growing interest in drug repositioning. Companies that offer a variety of broad platforms for identifying new indications have emerged; some have been successful in building their own pipelines of candidates with reduced risks and timelines associated with further clinical development. The business models and platforms offered by these companies will be validated if they are able to generate positive proof-of-concept clinical data for their repositioned compounds. This review describes the strategy of biomarker-guided repositioning of chemotherapeutic drugs for inflammation therapy, considering the repositioning of methylthiouracil (MTU), an antithyroid drug, as a potential anti-inflammatory reagent.

Clinical Evaluation of the Efficacy of Arthocare Forte, a Chondro-Protective and Anti-Arthritic Drug in the Management of Bacterial Plaque-Induced Chronic Periodontitis

BACKGROUND

Arthocare forte medication is made up of different constituents and the advantages offered by this disposition have not been explored in the management of chronic periodontitis.

AIM

The aim was to assess the clinical response of bacterial plaque-induced generalized chronic periodontitis to arthocare medication, and the relationship of age and gender to the prevalence of chronic periodontal disease.

SUBJECTS AND METHODS

This study was done at the Dental Surgery Clinic of the University of Calabar Teaching Hospital, Nigeria. It was a Prospective randomized controlled trial evaluating the effect of arthocare treatment on 81/162 patients with teeth mobility over a period of 5 years. All the patients (162) underwent root planing, and 81/162 (50%) were treated with arthocare for comparative analysis. The variables recorded were patient's age, gender, and degree of tooth mobility, periodontal pocket, and bleeding from the pocket after treatment. Statistical analysis was done using EPI INFO 7.

RESULTS

Majority of the patients were between 46 and 75 years in both control (n = 59/81, 72.8%) and experimental groups (n = 52/81, 64.2%). There were 86/162 (53.1%) males and 76/162 (46.9%) females, giving a male-to-female ratio of 1.1:1. Seventy-seven patients (95.1%) in the experimental group had total remission in comparison to 32/81 (39.5%) in control group which was statistically significant (P < 0.001).

CONCLUSION

The arthocare administered to patients in the experimental group speeds up the regenerative capacity and stability of the periodontium when compared with the control. Multicentre clinical trials are recommended to validate the use of arthocare forte in the treatment of generalized chronic periodontitis.

Oral submucous fibrosis: an update

Oral submucous fibrosis (OSF) is a premalignant condition caused by betel chewing. It is very common in Southeast Asia but has started to spread to Europe and North America. OSF can lead to squamous cell carcinoma, a risk that is further increased by concomitant tobacco consumption. OSF is a diagnosis based on clinical symptoms and confirmation by histopathology. Hypovascularity leading to blanching of the oral mucosa, staining of teeth and gingiva, and trismus are major symptoms. Major constituents of betel quid are arecoline from betel nuts and copper, which are responsible for fibroblast dysfunction and fibrosis. A variety of extracellular and intracellular signaling pathways might be involved. Treatment of OSF is difficult, as not many large, randomized controlled trials have been conducted. The principal actions of drug therapy include antifibrotic, anti-inflammatory, and antioxygen radical mechanisms. Potential new drugs are on the horizon. Surgery may be necessary in advanced cases of trismus. Prevention is most important, as no healing can be achieved with available treatments.

Effect of intensive oral hygiene regimen during pregnancy on periodontal health, cytokine levels, and pregnancy outcomes: a pilot study

BACKGROUND

Data are limited on the potential effect of intensive oral hygiene regimens and periodontal therapy during pregnancy on periodontal health, gingival crevicular fluid (GCF) and serum cytokines, and pregnancy outcomes.

METHODS

A clinical trial was conducted on 120 community-dwelling, 16- to 35-year-old pregnant women at 16 to 24 weeks of gestation. Each participant presented with clinical evidence of generalized, moderate-to-severe gingivitis. Oral hygiene products were provided, together with instructions for an intensive daily regimen of hygiene practices. Non-surgical therapy was provided at baseline. Oral examinations were completed at baseline and again at 4 and 8 weeks. In addition, samples of blood and GCF were collected at baseline and week 8. Mean changes in clinical variables and GCF and serum cytokine levels (interleukin [IL]-1β, IL-6, tumor necrosis factor [TNF]-α) between baseline and week 8 were calculated using paired t test. Pregnancy outcomes were recorded at parturition.

RESULTS

RESULTS indicated a statistically significant reduction in all clinical variables (P <0.0001) and decreased levels of TNF-α (P = 0.0076) and IL-1β (P = 0.0098) in GCF during the study period. The rate of preterm births (<37 weeks of gestation) was 6.7% (P = 0.113) and low birth weight (<2,500 g) was 10.2% (P = 1.00).

CONCLUSIONS

Among the population studied, intensive instructions and non-surgical periodontal therapy provided during 8 weeks at early pregnancy resulted in decreased gingival inflammation and a generalized improvement in periodontal health. Large-scale, randomized, controlled studies are needed to substantiate these findings.

Non-surgical periodontal therapy: An update on current evidence

Periodontal disease is an inflammatory condition that involves a complex interaction between pathogenic bacteria, environmental and acquired factors and host related factors. Till recently periodontal treatment was directed primarily towards reduction of bacterial load by subgingival debridement of root surfaces and modification of environmental risk factors. The current paradigm of periodontal disease stresses greater role of host-mediated inflammatory response in tissue destruction characteristic of periodontal disease. Various therapeutic modalities have been developed adjuvant to mechanical periodontal therapy. The use of laser and photodynamic therapy show great promise but their effectiveness has still not been conclusively proven. Chemotherapeutic agents, either systemic and local antimicrobials or host modulating drugs, played pivotal role in better and more predictable management of periodontal disease. The present review focuses on the best available evidence, for the current management of the chronic periodontal patients, gathered from systematic reviews and meta-analysis of mechanical non surgical periodontal therapy (NSPT) (subgingival debridement, laser therapy and photodynamic therapy) and the adjunctive chemotherapeutic approaches such as systematic and local antibiotics and antiseptics, subgingival pocket irrigation and host modulation therapies. The review also attempts to briefly introduce future developments in some of these modalities. At the end, the review summarizes the analysis of the current evidence that suggests that thorough subgingival debridement remains the mainstay of NSPT and that adjunct use of chemotherapeutic agents may offer better management of clinical parameters in periodontitis patients.

Anti-inflammatory Actions of Adjunctive Tetracyclines and Other Agents in Periodontitis and Associated Comorbidities

The non-antimicrobial properties of tetracyclines such as anti-inflammatory, proanabolic and anti-catabolic actions make them effective pharmaceuticals for the adjunctive management of chronic inflammatory diseases. An over-exuberant inflammatory response to an antigenic trigger in periodontitis and other chronic inflammatory diseases could contribute to an autoimmune element in disease progression. Their adjunctive use in managing periodontitis could have beneficial effects in curbing excessive inflammatory loading from commonly associated comorbidities such as CHD, DM and arthritis. Actions of tetracyclines and their derivatives include interactions with MMPs, tissue inhibitors of MMPs, growth factors and cytokines. They affect the sequence of inflammation with implications on immunomodulation, cell proliferation and angiogenesis; these actions enhance their scope, in treating a range of disease entities. Non-antimicrobial chemically modified tetracyclines (CMTs) sustain their diverse actions in organ systems which include anti-inflammatory, anti-apoptotic, anti-proteolytic actions, inhibition of angiogenesis and tumor metastasis. A spectrum of biological actions in dermatitis, periodontitis, atherosclerosis, diabetes, arthritis, inflammatory bowel disease, malignancy and prevention of bone resorption is particularly relevant to minocycline. Experimental models of ischemia indicate their specific beneficial effects. Parallel molecules with similar functions, improved Zn binding and solubility have been developed for reducing excessive MMP activity. Curbing excessive MMP activity is particularly relevant to periodontitis, and comorbidities addressed here, where specificity is paramount. Unique actions of tetracyclines in a milieu of excessive inflammatory stimuli make them effective therapeutic adjuncts in the management of chronic inflammatory disorders. These beneficial actions of tetracyclines are relevant to the adjunctive management of periodontitis subjects presenting with commonly prevalent comorbidities addressed here.

Herbal anti-inflammatory immunomodulators as host modulators in chronic periodontitis patients: a randomised, double-blind, placebo-controlled, clinical trial

PURPOSE

Host modulatory therapy has been proposed as a treatment for periodontal diseases. A class of herbal medicines, known to be immunomodulators, alters the activity of immune function through the regulation of informational molecules such as cytokines. In the current study, we tested the hypothesis that herbal immunomodulator drugs act as an adjuvant to scaling and root planing (SRP) in alleviating periodontal inflammation by improving clinical and biochemical parameters.

METHODS

Sixty healthy subjects (30 in each group) with moderate and severe chronic periodontitis were enrolled in a double-blind, placebo-controlled, double-masked randomised controlled trial. The control group was treated with SRP and a placebo, whereas the test group was treated with SRP followed by dietary supplementation of Septilin for 3 weeks. Periodontal clinical parameters and serum C-reactive protein (CRP) levels were evaluated for all patients at the baseline, 3 weeks, and 6 weeks.

RESULTS

Improved gingival index scores found in the test group as compared to the control group were found to be statistically significant only after 3 weeks (P<0.001). In contrast, the decrease in the sulcus bleeding index and pocket depth scores was statistically highly significant in the test group as compared to the control group after 3 weeks and 6 weeks (P<0.001). However, reduced clinical attachment level and CRP scores, as reflected in the test group as compared to the control group, were not found to be statistically significant after both 3 weeks (P>0.05) and 6 weeks (P>0.05).

CONCLUSIONS

The results of this clinical-biochemical study suggest that dietary supplementation with herbal immunomodulatory agents may be a promising adjunct to SRP and may aid in improving periodontal treatment outcomes.

Effects of nanosuspension and inclusion complex techniques on the in vitro protease inhibitory activity of naproxen

This study investigated the effects of nanosuspension and inclusion complex techniques on in vitro trypsin inhibitory activity of naproxen—a member of the propionic acid derivatives, which are a group of antipyretic, analgesic, and non-steroidal anti-inflammatory drugs. Nanosuspension and inclusion complex techniques were used to increase the solubility and anti-inflammatory efficacy of naproxen. The evaporative precipitation into aqueous solution (EPAS) technique and the kneading methods were used to prepare the nanosuspension and inclusion complex of naproxen, respectively. We also used an in vitro protease inhibitory assay to investigate the anti-inflammatory effect of modified naproxen formulations. Physiochemical properties of modified naproxen formulations were analyzed using UV, IR spectra, and solubility studies. Beta-cyclodextrin inclusion complex of naproxen was found to have a lower percentage of antitryptic activity than a pure nanosuspension of naproxen did. In conclusion, nanosuspension of naproxen has a greater anti-inflammatory effect than the other two tested formulations. This is because the nanosuspension formulation reduces the particle size of naproxen. Based on these results, the antitryptic activity of naproxen nanosuspension was noteworthy; therefore, this formulation can be used for the management of inflammatory disorders.

Omega 3 fatty acids as a host modulator in chronic periodontitis patients: a randomised, double-blind, palcebo-controlled, clinical trial

PURPOSE

Periodontitis is an infectious disease caused predominantly by gram-negative anerobes. The host inflammatory response to these bacteria causes alveolar bone loss that is characterized as periodontitis. Omega-3 fatty acids (ω-3 FAs) have anti-inflammatory properties, thus have been used to treat some chronic inflammatory diseases such as cardiovascular disease and rheumatoid arthritis. We aimed to evaluate the effect of dietary supplementation with ω-3 FAs as a host modulating agent in patients with chronic periodontitis.

METHODS

Sixty otherwise healthy subjects with moderate and severe chronic periodontitis were enrolled in our randomised, double-blind, placebo-controlled trial. The control group (CG, n=30) was treated with scaling and root planing (SRP) and given a placebo; the treatment group (TG, n=30) was treated with SRP and dietary supplementation of ω-3 FAs (one 300 mg tablet daily for 12 weeks). Periodontal clinical parameters and serum C-reactive protein (CRP) levels were evaluated in all patients at baseline, a 6-week and 12-week period after treatment.

RESULTS

A significant reduction in the gingival index, sulcus bleeding index, pocket depth, and clinical attachment level was found in the TG compared to the CG at a 12-week period. However, no statistically significant changes in serum CRP levels were found.

CONCLUSIONS

Our findings suggest that ω-3 FAs can successfully reduce gingival inflammation, pocket depth, and attachment level gain. Dietary supplementation with ω-3 FAs may have potential benefits as a host modulatory agent in the prevention and/or adjunctive management of chronic periodontitis.

Oral health education and therapy reduces gingivitis during pregnancy

BACKGROUND

Pregnant women demonstrate increases in gingivitis despite similar plaque levels to non-pregnant counterparts.

AIM

To evaluate an intensive protocol aimed at reducing gingivitis in pregnant women and provide pilot data for large-scale randomized controlled trials investigating oral hygiene measures to reduce pregnancy gingivitis and alter maternity outcomes.

MATERIALS AND METHODS

One hundred and twenty participants between 16 and 24 weeks gestation with Gingival Index (GI) scores ≥2 at ≥50% of tooth sites were enrolled. Plaque index (PI), gingival inflammation (GI), probing depth (PD), and clinical attachment levels (CAL) were recorded at baseline and 8 weeks. Dental prophylaxis was performed at baseline and oral hygiene instructions at baseline, 4 and 8 weeks. Pregnancy outcomes were recorded at parturition. Mixed-model analysis of variance was used to compare clinical measurements at baseline and 8 weeks.

RESULTS

Statistically significant reductions in PI, GI, PD, and CAL occurred over the study period. Mean whole mouth PI and GI scores decreased approximately 50% and the percentage of sites with PI and GI ≥2 decreased from 40% to 17% and 53% to 21.8%, respectively. Mean decreases in whole mouth PD and CAL of 0.45 and 0.24 mm, respectively, were seen.

CONCLUSIONS

Intensive oral hygiene regimen decreased gingivitis in pregnant patients.

Effect of quercetin on the production of nitric oxide in murine macrophages stimulated with lipopolysaccharide from Prevotella intermedia

Purpose

Nitric oxide (NO) is a short-lived bioactive molecule that is known to play an important role in the pathogenesis of periodontal disease. In the current study, we investigated the effect of the flavonoid quercetin on the production of NO in murine macrophages activated with lipopolysaccharide (LPS) from Prevotella intermedia, a pathogen related to inflammatory periodontal disease, and tried to elucidate the underlying mechanisms of action.

Methods

LPS was isolated from P. intermedia ATCC 25611 cells by the standard hot phenol-water method. The concentration of NO in cell culture supernatants was determined by measuring the accumulation of nitrite. Inducible NO synthase (iNOS) and heme oxygenase-1 (HO-1) protein expression, phosphorylation of c-Jun N-terminal kinase (JNK) and p38, inhibitory κB (IκB)-α degradation, and signal transducer and activator of transcription 1 (STAT1) phosphorylation were analyzed via immunoblotting.

Results

Quercetin significantly attenuated iNOS-derived NO production in RAW246.7 cells activated by P. intermedia LPS. In addition, quercetin induced HO-1 protein expression in cells activated with P. intermedia LPS. Tin protoporphyrin IX (SnPP), a competitive inhibitor of HO-1, abolished the inhibitory effect of quercetin on LPS-induced NO production. Quercetin did not affect the phosphorylation of JNK and p38 induced by P. intermedia LPS. The degradation of IκB-α induced by P. intermedia LPS was inhibited when the cells were treated with quercetin. Quercetin also inhibited LPS-induced STAT1 signaling.

Conclusions

Quercetin significantly inhibits iNOS-derived NO production in murine macrophages activated by P. intermedia LPS via anti-inflammatory HO-1 induction and inhibition of the nuclear factor-κB and STAT1 signaling pathways. Our study suggests that quercetin may contribute to the modulation of host-destructive responses mediated by NO and appears to have potential as a novel therapeutic agent for treating inflammatory periodontal disease.

The pleotropic role of statins: Could it be the imminent host modulation agent in periodontics?

Periodontal disease is a chronic inflammatory disease which represents a primarily anaerobic Gram-negative oral infection that results in gingival inflammation, loss of attachment, bone destruction. Bacterial endotoxins in the form of lipopolysaccharides (LPS) that are instrumental in generating a host-mediated tissue destructive immune response by mobilizing their defensive cells and releasing cytokines like Interleukin-1β (IL-1β), Tumor Necrosis Factor-α (TNF-α), and Interleukin-6 (IL-6), which lead to tissue destruction by stimulating the production of the collagenolytic enzymes: Matrix metalloproteinases (MMPs). Since the host-mediated tissue destruction is to be controlled, various means have been employed for modulating this response. Statins, 3-hydroxy-3-methylglutarylcoenzyme A (HMG CoA) reductase inhibitors, besides having lipid-lowering abilities also have antioxidant, antithrombotic, anti-inflammatory, immunomodulatory and osteomodulatory properties. All of these pleiotropic effects of statins point out to it perhaps becoming the novel host modulation agent in periodontics.

Subantimicrobial-dose doxycycline treatment increases serum cholesterol efflux capacity from macrophages

OBJECTIVE

Subantimicrobial-dose doxycycline (SDD) treatment has been reported to reduce the severity of chronic inflammation and to increase serum high-density lipoprotein cholesterol. In a double-blind, placebo-controlled clinical trial, we determined whether SDD affects the ability of serum to facilitate cholesterol removal from macrophages.

METHODS

Forty-five postmenopausal osteopenic women with periodontitis were randomly assigned to take placebo (n = 26) or doxycycline hyclate (20 mg, n = 19) tablets twice daily for 2 years. Serum samples were collected at baseline, 1-, and 2-year appointments. The cholesterol efflux capacity of serum from cultured human macrophages (THP-1) was measured.

RESULTS

SDD subjects demonstrated a significant increase in serum-mediated cholesterol efflux from macrophages at both time points compared to baseline (p < 0.04 for each). Mean cholesterol efflux levels over the first year of follow-up were 3.0 percentage points (unit change) higher among SDD subjects compared to placebo subjects (p = 0.010), while there was no significant difference in 2-year changes. There were no significant differences in the changes of apolipoprotein A-I, apolipoprotein A-II, or serum amyloid A levels between the groups.

CONCLUSIONS

Our results suggest that SDD treatment may reduce the risk of cardiovascular disease in this patient group by increasing the cholesterol efflux capacity of serum.

Effects of a Mikania laevigata extract on bone resorption and RANKL expression during experimental periodontitis in rats

Objectives

The Mikania laevigata extract (MLE) (popularly known in Brazil as "guaco") possesses anti-inflammatory properties. In the present study we tested the effects of MLE in a periodontitis experimental model in rats. We also investigated possible mechanisms underlying such effects.

Material and Methods

Periodontal disease was induced by a ligature placed around the mandibular first molars of each animal. Male Wistar rats were divided into 4 groups: non-ligated animals treated with vehicle; non-ligated animals treated with MLE (10 mg/kg, daily); ligature-induced animals treated with vehicle and ligature-induced animals treated with MLE (10 mg/kg, daily). Thirty days after the induction of periodontal disease, the animals were euthanized and mandibles and gingival tissues removed for further analysis.

Results

Morphometric analysis of alveolar bone loss demonstrated that MLE-treated animals presented a decreased alveolar bone loss and a lower expression of the activator of nuclear factor-κB ligand (RANKL) measured by immunohistochemistry. Moreover, gingival tissues from the MLE-treated group showed decreased neutrophil migration myeloperoxidase (MPO) assay.

Conclusions

These results indicate that MLE may be useful to control bone resorption during progression of experimental periodontitis in rats.

Azithromycin kills invasive Aggregatibacter actinomycetemcomitans in gingival epithelial cells

Aggregatibacter actinomycetemcomitans invades periodontal pocket epithelium and is therefore difficult to eliminate by periodontal scaling and root planing. It is susceptible to azithromycin, which is taken up by many types of mammalian cells. This led us to hypothesize that azithromycin accumulation by gingival epithelium could enhance the killing of intraepithelial A. actinomycetemcomitans. [(3)H]azithromycin transport by Smulow-Glickman gingival epithelial cells and SCC-25 oral epithelial cells was characterized. To test our hypothesis, we infected cultured Smulow-Glickman cell monolayers with A. actinomycetemcomitans (Y4 or SUNY 465 strain) for 2 h, treated them with gentamicin to eliminate extracellular bacteria, and then incubated them with azithromycin for 1 to 4 h. Viable intracellular bacteria were released, plated, and enumerated. Azithromycin transport by both cell lines exhibited Michaelis-Menten kinetics and was competitively inhibited by l-carnitine and several other organic cations. Cell incubation in medium containing 5 μg/ml azithromycin yielded steady-state intracellular concentrations of 144 μg/ml in SCC-25 cells and 118 μg/ml in Smulow-Glickman cells. Azithromycin induced dose- and time-dependent intraepithelial killing of both A. actinomycetemcomitans strains. Treatment of infected Smulow-Glickman cells with 0.125 μg/ml azithromycin killed approximately 29% of the intraepithelial CFU of both strains within 4 h, while treatment with 8 μg/ml azithromycin killed ≥82% of the CFU of both strains (P < 0.05). Addition of carnitine inhibited the killing of intracellular bacteria by azithromycin (P < 0.05). Thus, human gingival epithelial cells actively accumulate azithromycin through a transport system that facilitates the killing of intraepithelial A. actinomycetemcomitans and is shared with organic cations.

Perioceutics: Matrix metalloproteinase inhibitors as an adjunctive therapy for inflammatory periodontal disease

Matrix metalloproteinases (MMPs) form a group of more than 20 zinc-dependent enzymes that are crucial in the degradation of the main components in the extracellular matrix, and thereby play important roles in cell migration, wound healing, and tissue remodeling. MMPs have outgrown the field of extracellular matrix biology and have progressed toward being important regulatory molecules in inflammation, and hence are key components in the pathogenesis of periodontitis. This rise in status has led to the development of MMP inhibitors which can act as switches or delicate tuners in acute and chronic inflammation and the regenerative phase after inflammation. The new challenge in MMP research is to better understand the complex role these enzymes play in periodontal disease and to design inhibitors that are successful in the clinic. Perioceutics or the use of the pharmacological agents specifically developed to manage periodontitis is an interesting and emerging aid in the management of periodontal diseases along with mechanical debridement. The purpose of this review is to provide an introduction to MMPs and their inhibitors, the pathologic effects of a disturbance in the functions of enzyme cascades in balance with natural inhibitors, and highlight on the adjunctive use of MMP inhibitors in periodontal therapy and some of the current challenges with an overview of what has been achieved till date.

Non-antibacterial tetracycline formulations: clinical applications in dentistry and medicine

In 1983, it was first reported that tetracyclines (TCs) can modulate the host response, including (but not limited to) inhibition of pathologic matrix metalloproteinase (MMP) activity, and by mechanisms unrelated to the antibacterial properties of these drugs. Soon thereafter, strategies were developed to generate non-antibacterial formulations (subantimicrobial-dose doxycycline; SDD) and compositions (chemically modified tetracyclines; CMTs) of TCs as host-modulating drugs to treat periodontal and other inflammatory diseases. This review focuses on the history and rationale for the development of: (a) SDD which led to two government-approved medications, one for periodontitis and the other for acne/rosacea and (b) CMTs, which led to the identification of the active site of the drugs responsible for MMP inhibition and to studies demonstrating evidence of efficacy of the most potent of these, CMT-3, as an anti-angiogenesis agent in patients with the cancer, Kaposi's sarcoma, and as a potential treatment for a fatal lung disease (acute respiratory distress syndrome; ARDS). In addition, this review discusses a number of clinical studies, some up to 2 years' duration, demonstrating evidence of safety and efficacy of SDD formulations in humans with oral inflammatory diseases (periodontitis, pemphigoid) as well as medical diseases, including rheumatoid arthritis, post-menopausal osteopenia, type II diabetes, cardiovascular diseases, and a rare and fatal lung disease, lymphangioleiomyomatosis.

Effect of menopause on women's periodontium

Steroid sex hormones have a significant effect on different organ systems. As far as gingiva is concerned, they can influence the cellular proliferation, differentiation and growth of keratinocytes and fibroblasts. Estrogen is mainly responsible for alterations in blood vessels and progesterone stimulates the production of inflammatory mediators. In addition, some micro-organisms found in the human mouth synthesize enzymes needed for steroid synthesis and catabolism. In women, during puberty, ovulation, pregnancy, and menopause, there is an increase in the production of sex steroid hormones which results in increased gingival inflammation, characterized by gingival enlargement, increased gingival bleeding, and cervicular fluid flow and microbial changes.

Modulation of host cell signaling pathways as a therapeutic approach in periodontal disease

Recently, new treatment approaches have been developed to target the host component of periodontal disease. This review aims at providing updated information on host-modulating therapies, focusing on treatment strategies for inhibiting signal transduction pathways involved in inflammation. Pharmacological inhibitors of MAPK, NFκB and JAK/STAT pathways are being developed to manage rheumatoid arthritis, periodontal disease and other inflammatory diseases. Through these agents, inflammatory mediators can be inhibited at cell signaling level, interfering on transcription factors activation and inflammatory gene expression. Although these drugs offer great potential to modulate host response, their main limitations are lack of specificity and developments of side effects. After overcoming these limitations, adjunctive host modulating drugs will provide new therapeutic strategies for periodontal treatment.

Effect of anti-rheumatic agents on periodontal parameters and biomarkers of inflammation: a systematic review and meta-analysis

PURPOSE

Anti-rheumatic agents target common molecular pathways of inflammation in rheumatoid arthritis (RA) and periodontitis. The purpose of this study was to determine the relative effect of anti-rheumatic agents on the levels of inflammatory biomarkers and periodontal inflammation in RA patients with periodontitis.

METHODS

A systematic review and meta-analysis were conducted of studies comparing periodontal parameters of inflammation, such as bleeding on probing, and biomarkers of inflammation in RA patients with periodontitis and healthy adults with and without periodontitis. The search included the electronic databases MEDLINE, Cochrane Database of Systematic Reviews, and Google Scholar, inclusive through October 2011, with no language restrictions. Hand searches were conducted of the bibliographies of related journals and systematic reviews. Observational and interventional studies assessing the effects of antirheumatic therapy qualified for inclusion. Two reviewers performed independent data extraction and risk-of-bias assessment. Of the 187 identified publications, 13 studies fulfilled the inclusion criteria.

RESULTS

When compared to healthy adults without periodontitis, RA subjects were found to have significantly higher levels of bleeding on probing and limited evidence of higher levels of interleukin-1β and tumor necrosis factor-α (TNF-α) in gingival crevicular fluid and saliva. No consistent differences were found in periodontal parameters and inflammatory biomarkers between RA subjects and adults with periodontitis. Studies evaluating the effect of anti-TNF-α therapy in RA subjects with periodontitis have yielded inconsistent results.

CONCLUSIONS

There are limited data, however, to suggest that anti-TNF-α agents can reduce local production of inflammatory cytokines and periodontal inflammation in RA patients with periodontitis.

Periodontal pharmacotherapy - an updated review

Periodontal disease is mainly associated with the activity of bacteria which adhere to the tooth surface and form specific structure of bacterial biofilm. Periodontal bacteria cause inflammation of the gums and aggressive immune response, affecting the periodontium. The first phase of initial therapy - mechanical removal of dental plaque and calculus - is necessary. If this non-surgical therapy has proved to be unsuccessful, an alternative treatment with antimicrobial agents is then considered. Pharmacotherapy is based on systemic or local antibiotics and/or antiseptics, which are applied according to the severity of the disease. A number of recent periodontal studies present some of the pharmacological agents, that are directed against bacteria or a host immune response, are often chosen as an adjunct treatment option, but none of these antimicrobials were established as 'a gold standard' in the periodontal treatment. This review provides some present recommendation of pharmacological strategies, with particular emphasis on systemic and local antimicrobial therapy of periodontal disease.

Anti-inflammatory effects and the underlying mechanisms of action of daidzein in murine macrophages stimulated with Prevotella intermedia lipopolysaccharide

BACKGROUND AND OBJECTIVE

Host modulatory agents directed at inhibiting specific proinflammatory mediators could be beneficial in terms of attenuating periodontal disease progression and potentially enhancing therapeutic responses. The aim of this study was to investigate whether daidzein could modulate the production inflammatory mediators in macrophages stimulated with lipopolysaccharide (LPS) from Prevotella intermedia, a pathogen implicated in periodontal disease, and to delineate underlying mechanisms of action.

MATERIAL AND METHODS

LPS was extracted from P. intermedia ATCC 25611 cells by the standard hot phenol-water method. The amounts of nitric oxide (NO) and interleukin-6 (IL-6) secreted into the culture medium were assayed. A real-time PCR was performed to quantify inducible nitric oxide synthase (iNOS) and IL-6 mRNA expression. We used immunoblot analysis to characterize iNOS protein expression, phosphrylation of c-Jun N-terminal kinase (JNK) and p38, degradation of inhibitory κB-α (IκB-α), nuclear translocation of nuclear factor-κB (NF-κB) subunits and phosphorylation of signal transducer and activator of transcription 1 (STAT1). The DNA-binding activity of NF-κB was assessed by using ELISA-based kits.

RESULTS

Daidzein significantly inhibited the production of NO and IL-6, as well as their mRNA expression, in P. intermedia LPS-treated RAW264.7 cells. The JNK and p38 pathways were not involved in the regulation of LPS-induced NO and IL-6 release by daidzein. Daidzein inhibited the degradation of IκB-α induced by P. intermedia LPS. In addition, daidzein suppressed NF-κB transcriptional activity via regulation of the nuclear translocation and DNA-binding activity of NF-κB p50 subunit and blocked STAT1 phosphorylation.

CONCLUSION

Although additional studies are required to dissect the molecular mechanism of action, our results suggest that daidzein could be a promising agent for treating inflammatory periodontal disease. Further research in animal models of periodontitis is necessary to better evaluate the potential of daidzein as a novel therapeutic agent to treat periodontal disease.

Fluoxetine inhibits inflammatory response and bone loss in a rat model of ligature-induced periodontitis

BACKGROUND

Fluoxetine, a selective serotonin reuptake inhibitor, has been found recently to possess anti-inflammatory properties. The present study investigates the effects of fluoxetine on inflammatory tissue destruction in a rat model of ligature-induced periodontal disease.

METHODS

Thirty male Wistar rats were randomly assigned into three groups (n = 10 animals per group): 1) control rats (without ligature); 2) rats with ligature + placebo (saline; oral gavage); and 3) rats with ligature + fluoxetine (20 mg/kg/day in saline; oral gavage). Histologic analyses were performed on the furcation region and mesial aspect of mandibular first molars of rats sacrificed at 15 days after ligature-induced periodontal disease. Reverse transcription-polymerase chain reaction and zymography were performed to analyze the mRNA expression of interleukin (IL)-1β, cyclooxygenase (COX)-2, matrix metalloproteinase (MMP)-9 and inducible nitric oxide synthase and the MMP-9 activity, respectively, in gingival tissues samples.

RESULTS

Compared to the ligature + placebo group, alveolar bone loss was reduced in the fluoxetine group (P <0.05), and the amount of collagen fibers in the gingival tissue was maintained. Moreover, in gingival tissue sampled 3 days after ligature attachment, fluoxetine administration reduced IL-1β and COX-2 mRNA expression. Fluoxetine downregulated MMP-9 activity, without affecting MMP-9 mRNA expression induced by ligature, compared to the ligature + placebo group (P <0.05). These data suggest that fluoxetine suppressed proinflammatory responses, as well as proteolytic enzyme activity, induced by ligature.

CONCLUSION

In the present study, fluoxetine suppresses the inflammatory response and protects against periodontal bone resorption and destruction of collagen fibers, suggesting that fluoxetine can constitute a promising therapeutic approach for periodontal diseases.

Curcumin suppresses the production of interleukin-6 in Prevotella intermedia lipopolysaccharide-activated RAW 264.7 cells

Purpose

Curcumin is known to exert numerous biological effects including anti-inflammatory activity. In this study, we investigated the effects of curcumin on the production of interleukin-6 (IL-6) by murine macrophage-like RAW 264.7 cells stimulated with lipopolysaccharide (LPS) from Prevotella intermedia, a major cause of inflammatory periodontal disease, and sought to determine the underlying mechanisms of action.

Methods

LPS was prepared from lyophilized P. intermedia ATCC 25611 cells by the standard hot phenol-water method. Culture supernatants were collected and assayed for IL-6. We used real-time polymerase chain reaction to detect IL-6 mRNA expression. IκB-α degradation, nuclear translocation of NF-κB subunits, and STAT1 phosphorylation were characterized via immunoblotting. DNA-binding of NF-κB was also analyzed.

Results

Curcumin strongly suppressed the production of IL-6 at both gene transcription and translation levels in P. intermedia LPS-activated RAW 264.7 cells. Curcumin did not inhibit the degradation of IκB-α induced by P. intermedia LPS. Curcumin blocked NF-κB signaling through the inhibition of nuclear translocation of NF-κB p50 subunit. Curcumin also attenuated DNA binding activity of p50 and p65 subunits and suppressed STAT1 phosphorylation.

Conclusions

Although further study is required to explore the detailed mechanism of action, curcumin may contribute to blockade of the host-destructive processes mediated by IL-6 and appears to have potential therapeutic values in the treatment of inflammatory periodontal disease.

Biological approaches to the development of novel periodontal therapies--consensus of the Seventh European Workshop on Periodontology

BACKGROUND

Periodontitis remains a major public health issue and current management approaches have failed to impact upon the most high-risk proportion of the population and those with the most severe disease. The objective of this session was to assess if and how, current understanding of periodontitis provides the opportunity to develop new preventive and therapeutic strategies.

MATERIALS AND METHODS

Based on the current understanding of the pathophysiology of periodontal diseases, the Workshop discussed the potential of antimicrobial peptides, probiotics, pro-resolving lipid mediators, and micronutritional approaches. Evidence-based position papers and expert discussions formed the basis of deliberations.

RESULTS AND DISCUSSION

Current preventive and treatment approaches are only partially effective, and this appears due to the therapeutic focus remaining primarily upon biofilm management rather than embracing a pivotal role for inflammation as a driver of biofilm composition as well as tissue damage. There is a need to develop new, more effective, and efficient preventive and treatment approaches for gingivitis and periodontitis, which embrace recent advances in understanding of host modulation and inflammation resolution, as well as direct management of the microbiota.

Is long-term bisphosphonate therapy associated with benefits to the periodontium in postmenopausal women?

OBJECTIVE

The aim of this study was to compare the periodontium of postmenopausal women with known low bone mineral density who are receiving long-term bisphosphonate therapy with those who are not.

METHODS

The periodontal status of 28 white postmenopausal women with low bone density using bisphosphonate therapy for at least 2 years was compared with that of a matching group not using such therapy. All women underwent a cone-beam CT scan of the jaw and a complete periodontal examination evaluating for plaque score, periodontal probing depth, clinical attachment loss, bleeding on probing, and alveolar bone height.

RESULTS

Bisphosphonate users had higher plaque score, lower probing depth, and lesser clinical attachment loss compared with the controls. These differences were determined to be significant by both t test and Wilcoxon's tests. Bleeding on probing was lower and the alveolar bone height was higher in the bisphosphonate group than in controls, but these differences were not statistically significant. Linear models showed no significant interactions between plaque score and bisphosphonate use, suggesting that the association of periodontal status and outcome measures was constant across all levels of plaque scores. Bisphosphonate use was a significant factor for probing depth but was not significant for the other parameters when adjusted for plaque score.

CONCLUSIONS

Long-term bisphosphonate use seems to have some beneficial effects on the periodontium of postmenopausal women with low bone density, across all levels of plaque score.

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.

Melatonin inhibits Prevotella intermedia lipopolysaccharide-induced production of nitric oxide and interleukin-6 in murine macrophages by suppressing NF-κB and STAT1 activity

Although a range of biological and pharmacological activities of melatonin have been reported, little is known about its potential anti-inflammatory efficacy in periodontal disease. In this study, we investigated the effects of melatonin on the production of inflammatory mediators by murine macrophages stimulated with lipopolysaccharide (LPS) from Prevotella intermedia, a major cause of inflammatory reactions in the periodontium, and sought to determine the underlying mechanisms of action. Melatonin suppressed the production of nitric oxide (NO) and interleukin-6 (IL-6) at both gene transcription and translation levels in P. intermedia LPS-activated RAW264.7 cells. P. intermedia LPS-induced NF-κB-dependent luciferase activity was significantly inhibited by melatonin. Melatonin did not reduce NF-κB transcriptional activity at the level of IκB-α degradation. Melatonin blocked NF-κB signaling through the inhibition of nuclear translocation and DNA-binding activity of NF-κB p50 subunit and suppressed STAT1 signaling. Although further research is required to clarify the detailed mechanism of action, we conclude that melatonin may contribute to blockade of the host-destructive processes mediated by these two proinflammatory mediators and could be a highly efficient modulator of host response in the treatment of inflammatory periodontal disease.

Effects of luteolin on the release of nitric oxide and interleukin-6 by macrophages stimulated with lipopolysaccharide from Prevotella intermedia

BACKGROUND

Although a range of biologic and pharmacologic activities of luteolin has been reported, little is known about its potential as an agent to treat periodontal disease. In the present study, we investigated whether luteolin could downregulate the production of proinflammatory mediators in murine macrophage-like RAW264.7 cells stimulated with lipopolysaccharide (LPS) from Prevotella intermedia (Pi), a major cause of inflammatory periodontal disease, and we attempted to elucidate the possible mechanisms of action.

METHODS

LPS was prepared from lyophilized Pi ATCC 25611 cells by the standard hot phenol-water method. Culture supernatants were collected and assayed for nitric oxide (NO) and interleukin (IL)-6. We used real-time polymerase chain reaction to detect inducible NO synthase (iNOS) and IL-6 mRNA expression. iNOS expression, phosphorylation of JNK and p38, IκB-α degradation, nuclear translocation of nuclear factor-kappaB (NF-κB) subunits, and signal transducer and activator of transcription-1 (STAT1) phosphorylation were characterized via immunoblotting. DNA-binding of NF-κB was also analyzed.

RESULTS

Luteolin strongly suppressed the production of NO and IL-6 at both gene transcription and translation levels in Pi LPS-activated RAW264.7 cells. Mitogen-activated protein kinase pathways were not involved in the inhibition of Pi LPS-induced NO and IL-6 release by luteolin. Luteolin did not reduce NF-κB transcriptional activity at the level of IκB-α degradation. Luteolin blocked NF-κB signaling through inhibition of nuclear translocation and DNA binding activity of NF-κB p50 subunit and suppressed STAT1 signaling.

CONCLUSIONS

Although further research is encouraged to clarify the detailed mechanism of action, flavonoid luteolin may contribute to blockade of the host-destructive processes mediated by these two proinflammatory mediators and could have potential use in the treatment of inflammatory periodontal disease.

Effects of scaling and root planing and subantimicrobial dose doxycycline on gingival crevicular fluid levels of matrix metalloproteinase-8, -13 and serum levels of HsCRP in patients with chronic periodontitis

BACKGROUND

This study evaluates the efficacy of subantimicrobial dose doxycycline (SDD) in conjunction with scaling and root planing (SRP) on gingival crevicular fluid (GCF) levels of matrix metalloproteinase (MMP)-8 and -13 and on serum levels of high-sensitivity C-reactive protein (HsCRP) in patients with chronic periodontitis (CP).

METHODS

A total of 41 patients with CP and 17 healthy individuals were included in this randomized controlled trial. CP patients were randomly distributed into two groups. Study groups were established as Group I with SRP+placebo, Group II with SRP+SDD, and Group III as control. All CP patients received two regimens of SRP and Group II patients also received SDD for 6 weeks. At baseline and 6 weeks, GCF and blood were collected and clinical indices were recorded. The HsCRP level was assayed in the plasma on a nephelometer. The GCF levels of MMPs were assayed by an enzyme-linked immunosorbent assay.

RESULTS

Statistically significant differences in plaque index, gingival index (GI), probing depth (PD), GCF volumes, GCF MMP levels, and serum levels of HsCRP between pre-treatment and post-treatment were noted in both groups. Between groups there was a statistically significant decrease in PD, GI, and GCF levels of MMP-8 favoring the group receiving SDD adjunctive to SRP (P <0.05).

CONCLUSION

In this study, greater improvement was detected for PD, GI, and GCF levels of MMP-8 when using SRP+SDD compared to SRP+placebo.

Inflammation and uncoupling as mechanisms of periodontal bone loss

Periodontal disease is characterized by both inflammation and bone loss. Advances in research in both these areas have led to a new appreciation of not only each field but also the intimate relationship between inflammation and bone loss. This relationship has resulted in a new field of science called osteoimmunology and provides a context for better understanding the pathogenesis of periodontal disease. In this review, we discuss several aspects of the immuno-inflammatory host response that ultimately results in loss of alveolar bone. A proposal is made that periodontal inflammation not only stimulates osteoclastogenesis but also interferes with the uncoupling of bone formation and bone resorption, consistent with a pathologic process. Furthermore, arguments based on experimental animal models suggest a critical role of the spatial and temporal aspects of inflammation in the periodontium. A review of these findings leads to a new paradigm to help explain more fully the impact of inflammation on alveolar bone in periodontal disease so that it includes the effects of inflammation on uncoupling of bone formation from resorption.

Adjunctive treatment of chronic periodontitis with daily dietary supplementation with omega-3 Fatty acids and low-dose aspirin

BACKGROUND

Host modulatory therapy has been proposed as a treatment for periodontal diseases. Omega-3 (ω-3) polyunsaturated fatty acids (PUFAs), including docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), were shown to have therapeutic anti-inflammatory and protective actions in inflammatory diseases including periodontitis. The goal of this study was to test an innovative strategy for periodontal treatment in a clinical experiment.

METHODS

Eighty healthy subjects (40 in each group) with advanced chronic periodontitis were enrolled in Mansoura, Egypt, in a parallel-design, double-masked clinical study. The control group was treated with scaling and root planing (SRP) and a placebo, whereas the ω-3 group was treated with SRP followed by dietary supplementation of fish oil (900 mg EPA + DHA) and 81 mg aspirin daily. Saliva samples were obtained from all patients at baseline and 3 and 6 months for evaluation of receptor activator of nuclear factor-kappa B ligand (RANKL) and matrix metalloproteinase-8 (MMP-8). Plaque and gingival indices, bleeding on probing, probing depths, and attachment levels were recorded at the same time points.

RESULTS

Statistical analyses demonstrated a significant reduction in probing depths and a significant attachment gain after 3 and 6 months in the ω-3 group compared to baseline and the control group (P <0.05). Salivary RANKL and MMP-8 levels showed significant reductions in the ω-3 group in response to treatment at 3 and 6 months and compared to the control group at 6 months (P <0.01). Supplementation with ω-3 + aspirin resulted in a significant shift in the frequency of pockets with probing depths <4 mm (P <0.05).

CONCLUSION

The results of this preliminary clinical study suggest that dietary supplementation with ω-3 PUFAs and 81 mg aspirin may provide a sustainable, low-cost intervention to augment periodontal therapy.