Bestatin as a treatment modality in experimental periodontitis.

BACKGROUND: Chronic periodontitis (CP), the most prevalent dysbiotic bacteria-driven chronic inflammatory disease, is an underestimated global health problem in itself, and due to a causative relationship with other disorders such as cardiovascular diseases or Alzheimer disease. The CP pathogenesis is primarily driven by Porphyromonas gingivalis in humans, and Porphyromonas gulae in dogs. These microorganisms initiate a pathogenic shift in the composition of the tooth-surface microflora. Our objective was to evaluate antimicrobial effects of bestatin, a potential CP drug candidate. METHODS: We evaluated bestatin bacteriostatic efficiency against periodontopathogens in planktonic cultures via microplate assay, and mono- and multispecies oral biofilm models. Neutrophil bactericidal activities, such as phagocytosis, were investigated in vitro using granulocytes isolated from the peripheral blood. The therapeutic efficacy and the immunomodulatory function of bestatin was assessed in a murine model of CP. RESULTS: Bestatin exhibited bacteriostatic activity against both P. gingivalis and P. gulae, and controlled the formation and species composition of the biofilm. We demonstrated that bestatin promotes the phagocytosis of periodontopathogens by neutrophils. Finally, we found that providing bestatin in the animal feed prevented alveolar bone resorption. CONCLUSIONS: We show that in a murine model of CP bestatin not only shifted the biofilm species composition from pathogenic to a commensal one, but also promoted bacteria clearance by immune cells and alleviated inflammation. Taken together, these results suggest that bestatin is a promising drug choice for the treatment and/or prevention of periodontitis and clinical trials are required to fully evaluate its potency.

Discovery of Novel Potential Reversible Peptidyl Arginine Deiminase Inhibitor.

Citrullination, a posttranslational modification, is catalyzed by peptidylarginine deiminases (PADs), a unique family of enzymes that converts peptidyl-arginine to peptidyl-citrulline. Overexpression and/or increased PAD activity is observed in rheumatoid arthritis (RA), Alzheimer's disease, multiple sclerosis, and cancer. Moreover, bacterial PADs, such as Porphyromonas gingivalis PAD (PPAD), may have a role in the pathogenesis of RA, indicating PADs as promising therapeutic targets. Herein, six novel compounds were examined as potential inhibitors of human PAD4 and PPAD, and compared to an irreversible PAD inhibitor, Cl-amidine. Four of the tested compounds (compounds 2, 3, 4, and 6) exhibited a micromolar-range inhibition potency against PAD4 and no effect against PPAD in the in vitro assays. Compound 4 was able to inhibit the PAD4-induced citrullination of H3 histone with higher efficiency than Cl-amidine. In conclusion, compound 4 was highly effective and presents a promising direction in the search for novel RA treatment strategies.

Effects of statins on multispecies oral biofilm identify simvastatin as a drug candidate targeting Porphyromonas gingivalis.

BACKGROUND: Statins effectively reduce risk of cardiovascular-related morbidity and mortality in patients with hyperlipidemia, hypertension, or type 2 diabetes. In addition to lowering cholesterol levels, several studies have attributed statins with immunomodulatory and bactericidal properties. Therefore, the aim of this study was to investigate statins' antimicrobial activity against periodontal homeostasis bacteria. METHODS: Statin effect on bacterial growth was tested using planktonic monocultures and multibacterial biofilms. The latter consisted of five microbial species (Porphyromonas gingivalis, Fusobacterium nucleatum, Actinomyces naeslundii, Tannerella forsythia, and Streptococcus gordonii) associated with dysbiosis of the oral microbiota underlying establishment and perpetuation of periodontitis. RESULTS: All four tested statins efficiently inhibited P. gingivalis growth and significantly decreased the cumulative bacterial load in developing and established biofilms. Simvastatin was most efficient and decreased P. gingivalis counts more than 1,300-fold relative to the control. CONCLUSIONS: These findings suggest that similar effects on bacterial composition of the dental plaque may occur in vivo in patients on statins, thus, leading to a shift of the oral microbiome from a dysbiotic to a more homeostatic one. Simvastatin, being highly effective against P. gingivalis while not affecting commensal microbiota, possesses many properties qualifying it as a potential adjunctive treatment for chronic periodontitis. Further studies are needed to evaluate whether similar effects on bacterial composition of the dental plaque may occur in vivo in patients on statins, thus, leading to a shift of the oral microflora from dysbiotic to a more homeostatic one.

Impact of Porphyromonas gingivalis Peptidylarginine Deiminase on Bacterial Biofilm Formation, Epithelial Cell Invasion, and Epithelial Cell Transcriptional Landscape.

Peptidylarginine deiminase (PPAD) is a virulence factor unique to pathogenic Porphyromonas species, especially P. gingivalis. Mechanistically, PPAD activity, in conjunction with Arg-specific gingipains, generates protein fragments with citrullinated C-termini. Such polypeptides are potential de novo epitopes that are key drivers of rheumatoid arthritis. This process could underlie the observed clinical association between rheumatoid arthritis and periodontitis. However, the role of PPAD in host colonization by P. gingivalis and, subsequently, in triggering periodontitis is not known. Therefore, the aim of the current study was to delineate the role of PPAD in bacterial biofilm formation, and to define whether adherence to, invasion of, and host responses to bacteria of gingival keratinocytes depend on PPAD activity. We studied these aspects using PPAD-competent and PPAD-incompetent strains of P. gingivalis, and demonstrated that neither biofilm formation nor its composition was affected by PPAD activity. Similarly, flow cytometry revealed that PPAD did not impact the ability of P. gingivalis to adhere to and, subsequently, invade keratinocytes. Network analyses of gene expression patterns, however, revealed a group of host genes that were sensitive to PPAD activity (CXCL8, IL36G, CCL20, and IL1B). These genes can be categorized as potent immune modulators belonging to the interleukin 1 system, or chemoattractants of lymphocytes and neutrophils. Thus, we conclude that PPAD, although it is a potent modulator of the immune response, does not affect bacterial biofilm formation or the ability of P. gingivalis to adhere to and invade gingival epithelial cells.

A Guide to Medications Inducing Salivary Gland Dysfunction, Xerostomia, and Subjective Sialorrhea: A Systematic Review Sponsored by the World Workshop on Oral Medicine VI.

BACKGROUND: Medication-induced salivary gland dysfunction (MISGD), xerostomia (sensation of oral dryness), and subjective sialorrhea cause significant morbidity and impair quality of life. However, no evidence-based lists of the medications that cause these disorders exist. OBJECTIVE: Our objective was to compile a list of medications affecting salivary gland function and inducing xerostomia or subjective sialorrhea. DATA SOURCES: Electronic databases were searched for relevant articles published until June 2013. Of 3867 screened records, 269 had an acceptable degree of relevance, quality of methodology, and strength of evidence. We found 56 chemical substances with a higher level of evidence and 50 with a moderate level of evidence of causing the above-mentioned disorders. At the first level of the Anatomical Therapeutic Chemical (ATC) classification system, 9 of 14 anatomical groups were represented, mainly the alimentary, cardiovascular, genitourinary, nervous, and respiratory systems. Management strategies include substitution or discontinuation of medications whenever possible, oral or systemic therapy with sialogogues, administration of saliva substitutes, and use of electro-stimulating devices. LIMITATIONS: While xerostomia was a commonly reported outcome, objectively measured salivary flow rate was rarely reported. Moreover, xerostomia was mostly assessed as an adverse effect rather than the primary outcome of medication use. This study may not include some medications that could cause xerostomia when administered in conjunction with others or for which xerostomia as an adverse reaction has not been reported in the literature or was not detected in our search. CONCLUSIONS: We compiled a comprehensive list of medications with documented effects on salivary gland function or symptoms that may assist practitioners in assessing patients who complain of dry mouth while taking medications. The list may also prove useful in helping practitioners anticipate adverse effects and consider alternative medications.

Microbiological and bioinformatics analysis of primary Sjogren's syndrome patients with normal salivation.

BACKGROUND: Reduced salivation is considered a major clinical feature of most but not all cases of primary Sjögren's syndrome (pSS). Reduced saliva flow may lead to changes in the salivary microbiota. These changes have mainly been studied with culture that typically recovers only 65% of the bacteria present. OBJECTIVE: This study was to use high throughput sequencing, covering both cultivated and not-yet-cultivated bacteria, to assess the bacterial microbiota of whole saliva in pSS patients with normal salivation. METHODS: Bacteria of whole unstimulated saliva from nine pSS patients with normal salivation flow and from nine healthy controls were examined by high throughput sequencing of the hypervariable region V1V2 of 16S rRNA using the 454 GS Junior system. Raw sequence reads were subjected to a species-level, reference-based taxonomy assignment pipeline specially designed for studying the human oral microbial community. Each of the sequence reads was BLASTN-searched against a database consisting of reference sequences representing 1,156 oral and 12,013 non-oral species. Unassigned reads were then screened for high-quality non-chimeras and subjected to de novo species-level operational taxonomy unit (OTU) calling for potential novel species. Downstream analyses, including alpha and beta diversities, were analyzed using the Quantitative Insights into Microbial Ecology (QIIME) pipeline. To reveal significant differences between the microbiota of control saliva and Sjögren's saliva, a statistical method introduced in Metastats www.metastats.cbcb.umd.edu was used. RESULTS: Saliva of pSS patients with normal salivation had a significantly higher frequency of Firmicutes compared with controls (p=0.004). Two other major phyla, Synergistetes and Spirochaetes, were significantly depleted in pSS (p=0.001 for both). In addition, we saw a nearly 17% decrease in the number of genera in pSS (25 vs. 30). While Prevotella was almost equally abundant in both groups (25% in pSS and 22% in controls), about a twofold increase in pSS of Streptococcus (28% vs. 17%) and Veillonella (26% vs. 12%) was detected. Prevotella melaninogenica was the major species in controls (13%) while Veillonella atypica and the Veillonella parvula groups dominated in patient samples (14 and 14%). The scarcity in bacterial species in pSS compared with controls was also demonstrated by alpha and beta diversity analyses, as well as read abundance depicted in a phylogenetic tree. CONCLUSIONS: While Firmicutes was significantly higher in pSS patients than in controls, Synergistetes and Spirochaetes were significantly lower. The number of bacterial genera and species was also lower. These data showed that microbial dysbiosis is another key characteristic of pSS whole saliva which can occur independent of hyposalivation.

World Workshop on Oral Medicine VI: a systematic review of medication-induced salivary gland dysfunction: prevalence, diagnosis, and treatment.

OBJECTIVES: Medication-induced salivary gland dysfunction (MISGD) causes significant morbidity resulting in decreased quality of life. This systematic review assessed the literature on the prevalence, diagnosis, treatment, and prevention of MISGD. MATERIALS AND METHODS: Electronic databases were searched for articles related to MISGD through June 2013. Four independent reviewers extracted information regarding study design, study population, interventions, outcomes, and conclusions for each article. Only papers with acceptable degree of relevance, quality of methodology, and strength of evidence were retained for further analysis. RESULTS: There were limited data on the epidemiology of MISGD. Furthermore, various methods were used to assess salivary flow rate or xerostomia. Preventive and therapeutic strategies included substitution of medications, oral, or systemic therapy with sialogogues, use of saliva substitutes or of electro-stimulating devices. Although there are promising approaches to improve salivary gland function, most studies are characterized by small numbers and heterogeneous methods. CONCLUSIONS: Physicians and dentists should identify the medications associated with xerostomia and salivary gland dysfunction through a thorough medical history. Preferably, health care providers should measure the unstimulated and stimulated whole salivary flow rates of all their patients so that these values can be used as a baseline to rate the complaints of patients who subsequently claim to experience xerostomia or salivary gland dysfunction as well as the possibilities of effectively treating this condition. CLINICAL RELEVANCE: MISGD remains a major burden for the population. This systematic review provides a contemporary in-depth description of the diagnosis and treatment of MISGD.

World Workshop on Oral Medicine VI: clinical implications of medication-induced salivary gland dysfunction.

OBJECTIVE: This study aimed to systematically review the available literature on the clinical implications of medication-induced salivary gland dysfunction (MISGD). STUDY DESIGN: The systematic review was performed using PubMed, Embase, and Web of Science (through June 2013). Studies were assessed for degree of relevance and strength of evidence, based on whether clinical implications of MISGD were the primary study outcomes, as well as on the appropriateness of study design and sample size. RESULTS: For most purported xerogenic medications, xerostomia was the most frequent adverse effect. In the majority of the 129 reviewed papers, it was not documented whether xerostomia was accompanied by decreased salivary flow. Incidence and prevalence of medication-induced xerostomia varied widely and was often associated with number and dose of medications. Xerostomia was most frequently reported to be mild-to-moderate in severity. Its onset occurred usually in the first weeks of treatment. There was selected evidence that medication-induced xerostomia occurs more frequently in women and older adults and that MISGD may be associated with other clinical implications, such as caries or oral mucosal alterations. CONCLUSIONS: The systematic review showed that MISGD constitutes a significant burden in many patients and may be associated with important negative implications for oral health.

Evaluation of the clinical efficacy of Biotène Oral Balance in patients with secondary Sjögren's syndrome: a pilot study.

The objective of the present study was to evaluate the efficacy of Oral Balance saliva substitute in alleviating dry mouth symptoms in a sample of patients with secondary Sjögren's syndrome. Twenty-one consecutive secondary Sjögren's syndrome patients with dry mouth complaints and hyposalivation were included in this study. Patients used a lactoperoxidase-system-containing gel (Biotène Oral Balance) for 4 weeks. The effects on subjective oral symptoms were recorded by means of a 7-items questionnaire which contained questions regarding dry mouth sensation and its effect on chewing, swallowing, taste, speech, burning sensation and denture retention. The severity of symptoms was assessed using a visual analogical scale. Oral symptom scores and unstimulated whole salivary flow were recorded at baseline and after 4 weeks' use of the product. Two patients withdrew from the study, because of nausea and unpleasant taste caused by the product. Nineteen patients (all women, mean age 52.7 years) participated throughout the entire study. Wilcoxon signed-ranked tests indicated significant improvements in visual analogical scale scores posttreatment for 5 of the 7 items on the oral dryness questionnaire, although no increase in salivary flow was found. However, the improvement in certain variables did not take a positive course in all cases. Patients with lower salivary flow at baseline tended to have greater improvement in oral symptoms. The study suggests that the use of Oral Balance gel is effective in alleviating the dry mouth symptoms in secondary Sjögren's syndrome patients, but a randomized controlled trial is needed to assess the placebo effect.

Oral mucosa involvement in rheumatoid arthritis, systemic lupus erythematosus and systemic sclerosis.

OBJECTIVES: To estimate the frequency and character of oral mucosal lesions in patients with rheumatoid arthritis, systemic lupus erythematosus and systemic sclerosis. Furthermore, the relation between oral mucosal involvement and hyposalivation was investigated. DESIGN: Case-control study. SETTING: Rheumatology Clinic, University Hospital "Mother Theresa" in Tirana, Albania. PARTICIPANTS: 124 consecutive hospitalised patients (88 with rheumatoid arthritis, 22 with systemic lupus erythematosus and 14 with systemic sclerosis) and 124 age- and gender- matched healthy controls. METHODS: Oral lesions were clinically examined and classified according to their morphologic aspects and localisation. Examination included also measurement of unstimulated whole salivary flow. MAIN OUTCOME MEASURES: Frequency of oral mucosal lesions and hyposalivation. RESULTS: Oral mucosal lesions were observed in 58.9% of patients, but in only 33.1% of control subjects. Clinical aspects of lesions varied, and palate, buccal and labial mucosa, and tongue were the most affected sites. No significant associations were found between presence of oral lesions and hyposalivation, except oral candidosis which was associated with hyposalivation in controls. CONCLUSIONS: Patients with rheumatoid arthritis, systemic lupus erythematosus and systemic sclerosis have a higher burden of oral mucosa disease than a healthy population. Collaboration of rheumatology and oral medicine units should allow appropriate management of these patients.

Sicca symptoms, and lacrimal and salivary flow in Albanian patients with rheumatoid arthritis.

BACKGROUND: Rheumatoid arthritis affects primarily the synovial joints, but is often accompanied by extra-articular manifestations, including lacrimal and salivary gland involvement. The aim of the present study was to estimate the prevalence of ocular and oral sicca symptoms and reduced lacrimal and salivary flow in rheumatoid arthritis and the relation between sicca symptoms and objective measures of lacrimal and salivary flow. METHODS: We examined 88 consecutive hospitalized patients with rheumatoid arthritis and 88 age- and gender-matched healthy controls. The examination included the standardized questionnaire for keratoconjunctivitis sicca and xerostomia which forms part of the European criteria for Sjögren's syndrome, the Schirmer's I test and measurement of unstimulated whole salivary flow rate. RESULTS: A significantly higher proportion of patients (40.9%) reported ocular sicca symptoms than healthy matched controls (8.0%). Further, a significantly higher proportion of patients (44.3%) reported oral sicca symptoms compared to controls (13.6%). 48.9% of the patients had low Schirmer I score, compared to 20.5% of controls. Reduced salivary flow was found in 27.3% of patients, compared to 9.1% of controls. The differences in lacrimal and salivary flow between patient and control group were statistically significant. The minimum prevalence of secondary Sjögren's syndrome was 14.8%. Weak association was observed between sicca symptoms and the objective measures of lacrimal and salivary flow in patients, and no association was detected in control subjects. CONCLUSIONS: Sicca symptoms and reduced lacrimal and salivary flow were common manifestations in rheumatoid arthritis and should be given adequate consideration during management of patients with rheumatoid arthritis.