Experimental arthritis in rats induces biomarkers of periodontitis which are ameliorated by gene therapy with tissue inhibitor of matrix metalloproteinases

Current status and future prospects of stomatology research

Research in stomatology (dental medicine) continues to expand globally and is oriented towards solving clinical issues, focusing on clarifying the clinical relevance and potential mechanisms of oral‍-‍systemic connections via clinical epidemiology, oral microecological characterization, and the establishment of animal models. Interdisciplinary integration of materials science and tissue engineering with stomatology is expected to lead to the creation of innovative materials and technologies to better resolve the most prevalent and challenging clinical issues such as peri-implantitis, soft and hard tissue defects, and dentin hypersensitivity. With the rapid development of artificial intelligence (AI), 5th generation mobile communication technology (5G), and big data applications, "intelligent stomatology" is emerging to build models for better clinical diagnosis and management, accelerate the reform of education, and support the growth and advancement of scientific research. Here, we summarized the current research status, and listed the future prospects and limitations of these three aspects, aiming to provide a basis for more accurate etiological exploration, novel treatment methods, and abundant big data analysis in stomatology to promote the translation of research achievements into practical applications for both clinicians and the public.

Differential associations of rheumatoid arthritis and periodontitis or tooth loss: A cross-sectional study

AIM

To study the association between periodontitis, tooth loss, and rheumatoid arthritis (RA) by using a large national dataset.

MATERIALS AND METHODS

An observational cross-sectional study was performed using the National Health and Nutrition Examination Survey cycles (2009-2014). RA status was detected using a questionnaire. Periodontal status was assigned on the basis of the clinical attachment level and periodontal pocket depth. Dentition status was assessed by the number of permanent teeth observed. We examined the association between RA as exposure and moderate/severe periodontitis and non-functional dentition as outcomes. We progressively adjusted our models for different sets of potential confounders.

RESULTS

Moderate/severe periodontitis was more prevalent in participants reporting RA (53% vs. 41.5%, p = .0003). Non-functional dentition was more prevalent in participants with RA (41% vs. 15.5%, p = .0001). The fully adjusted model showed that participants with RA had higher odds of having non-functional dentition (odds ratio 1.8, 95% confidence interval [CI] 1.3-2.3, p = .0001) but no association with moderate/severe periodontitis (prevalence ratio 1.01, 95% CI 0.9-1.1, p = .9).

CONCLUSION

RA was associated with a higher likelihood of having non-functional dentition but did not show any association with periodontitis after adjusting for the risk factors to control their confounding effect.

Oral health associated with incident diabetes but not other chronic diseases: A register-based cohort study

Introduction

Oral infectious diseases are common chronic oral diseases characterized by a chronic inflammatory condition. We investigated chronic oral diseases as potential risk factors for systemic chronic diseases, diabetes mellitus, connective tissue diseases, seropositive rheumatoid arthritis, ulcerative colitis, and Crohn's disease, as well as severe psychotic and other severe mental disorders.

Methods

The cohort comprised 68,273 patients aged ≥ 29 years with at least one dental visit to the Helsinki City Health Services between 2001 and 2002. The cohort was linked to the data on death (Statistics Finland), cancer (Finnish Cancer Registry), and drug reimbursement (Finnish Social Insurance Institution) and followed until death or the end of 2013. The outcomes of interest were the incidences of chronic diseases measured starting with special refund medication, which means Social Insurance Institution partly or fully reimburses medication costs. Outcomes of interest were diabetes mellitus, connective tissue diseases, seropositive rheumatoid arthritis, ulcerative colitis and Crohn's disease, and severe mental disorders.

Results

The mean follow-up time was 9.8 years. About 25% of the study population had periodontitis, 17% caries, over 70% apical periodontitis, and 9% <24 teeth at the start of follow-up. Diabetes was the only chronic systemic condition associated with oral health variables. Having 24 to 27 teeth was associated with a higher incidence rate ratio (IRR) (1.21, 95% confidence interval 1.09-1.33) compared to having 28 or more teeth; the IRR for having 23 or less was 1.40 (1.22-1.60). Having periodontitis (1.10, 1.01-1.20), caries (1.12, 1.01-1.23), or apical periodontitis (1.16, 1.04-1.30) is also associated with a higher risk of diabetes.

Conclusion

Our epidemiological 10 years follow-up study suggests that the association exists between chronic oral diseases and diabetes, warranting close collaboration among patient's healthcare professionals.

Pros and cons of causative association between periodontitis and rheumatoid arthritis

Research in recent decades has brought significant advancements in understanding of the molecular basis of the etiology of autoimmune diseases, including rheumatoid arthritis, a common systemic disease in which an inappropriate or inadequate immune response to environmental challenges leads to joint destruction. Recent studies have indicated that the classical viewpoint of the immunological processes underpinning the pathobiology of rheumatoid arthritis is restricted and needs to be expanded to include a more holistic and interdisciplinary approach incorporating bacteria-induced inflammatory reactions as an important pathway in rheumatoid arthritis etiology. Here, we discuss in detail data showing the clinical and molecular association of rheumatoid arthritis development with periodontal diseases. We also describe the unique role of periopathogens, which have been proposed to be crucial in the initiation and progression of this autoimmune pathological disorder.

Maladaptive innate immune training of myelopoiesis links inflammatory comorbidities

Bone marrow (BM)-mediated trained innate immunity (TII) is a state of heightened immune responsiveness of hematopoietic stem and progenitor cells (HSPC) and their myeloid progeny. We show here that maladaptive BM-mediated TII underlies inflammatory comorbidities, as exemplified by the periodontitis-arthritis axis. Experimental-periodontitis-related systemic inflammation in mice induced epigenetic rewiring of HSPC and led to sustained enhancement of production of myeloid cells with increased inflammatory preparedness. The periodontitis-induced trained phenotype was transmissible by BM transplantation to naive recipients, which exhibited increased inflammatory responsiveness and disease severity when subjected to inflammatory arthritis. IL-1 signaling in HSPC was essential for their maladaptive training by periodontitis. Therefore, maladaptive innate immune training of myelopoiesis underlies inflammatory comorbidities and may be pharmacologically targeted to treat them via a holistic approach.

Impact of systemic factors in shaping the periodontal microbiome

Since 2010, next-generation sequencing platforms have laid the foundation to an exciting phase of discovery in oral microbiology as it relates to oral and systemic health and disease. Next-generation sequencing has allowed large-scale oral microbial surveys, based on informative marker genes, such as 16S ribosomal RNA, community gene inventories (metagenomics), and functional analyses (metatranscriptomics), to be undertaken. More specifically, the availability of next-generation sequencing has also paved the way for studying, in greater depth and breadth, the effect of systemic factors on the periodontal microbiome. It was natural to investigate systemic diseases, such as diabetes, in such studies, along with systemic conditions or states, , pregnancy, menopause, stress, rheumatoid arthritis, and systemic lupus erythematosus. In addition, in recent years, the relevance of systemic "variables" (ie, factors that are not necessarily diseases or conditions, but may modulate the periodontal microbiome) has been explored in detail. These include ethnicity and genetics. In the present manuscript, we describe and elaborate on the new and confirmatory findings unveiled by next-generation sequencing as it pertains to systemic factors that may shape the periodontal microbiome. We also explore the systemic and mechanistic basis for such modulation and highlight the importance of those relationships in the management and treatment of patients.

Short- and long-term treatment with TNF-α inhibits the induction of osteoblastic differentiation in cyclic tensile-stretched periodontal ligament fibroblasts

Background

Cyclic tensile stretching (CTS) induces osteoblastic differentiation of periodontal ligament fibroblasts (PDLF). On the other hand, increased concentrations of tumour necrosis factor-α (TNF-α) are found in inflammatory conditions, leading to periodontal disease and tooth loss. Accordingly, our aim was to investigate the short- and long-term effect of TNF-α on the response of human PDLF to CTS and its implication on osteoblastic differentiation.

Methods

PDLF were either pre-incubated for 4 hours or were repeatedly exposed to TNF-α for up to 50 days and then subjected to CTS. Gene expression was determined by quantitative real-time polymerase chain reaction. Activation of mitogen-activated protein kinase (MAPK) was monitored by western analysis and cell proliferation by bromodeoxyuridine incorporation. Intracellular reactive oxygen species were determined by the 2´, 7´-dichlorofluorescein-diacetate assay and osteoblastic differentiation by Alizarin Red-S staining after an osteo-inductive period of 21 days.

Results

CTS of PDLF induced an immediate upregulation of the c-fos transcription factor and, further downstream the overexpression of alkaline phosphatase and osteopontin, two major osteoblast marker genes. A 4-hour pre-incubation with TNF-α repressed these effects. Similarly, long-term propagation of PDLF along with TNF-α diminished their osteoblastic differentiation capacity and suppressed cells’ CTS-elicited responses. The observed phenomena were not linked with TNF-α-induced premature senescence or oxidative stress. While CTS induced the activation of MAPKs, involved in mechanotransduction, TNF-α treatment provoked a small delay in the phosphorylation of extracellular signal-regulated kinase and c-Jun N-terminal kinase.

Conclusion

Increased concentrations of TNF-α, such as those recorded in many inflammatory diseases, suppress PDLF’s immediate responses to mechanical forces compromising their osteoblastic differentiation potential, possibly leading to tissue’s impaired homeostasis.

An appraisal of the role of specific bacteria in the initial pathogenesis of periodontitis

BACKGROUND

Historically, inflammatory periodontal diseases (gingivitis and periodontitis) have been recognized as being primarily of bacterial origin. Bacteria are necessary for disease development, but the presence of specific bacteria does not guarantee progression to periodontitis. Periodontitis is a multifactorial disease; specific bacteria are associated with disease, but may not be the target of treatment. Gingivitis and periodontitis are inflammatory conditions associated with bacterial overgrowth.

AIM

To analyse evidence for established thought that specific bacteria directly participate in the pathogenesis of periodontitis and question the long-held tenet that penetration of the periodontal connective tissues by bacteria and their products is a significant phase in the initial development of periodontitis.

METHODS

The literature was searched for studies on initiation of gingivitis and periodontitis by specific pathogens. The search results were insufficient for a systematic review and have been summarized in a commentary instead.

RESULTS

There is very little evidence in the literature to support the commonly held concept that specific bacteria initiate periodontitis.

CONCLUSION

We present evidence for a paradigm supporting the central role of inflammation, rather than specific microbiota, in the early pathogenesis of periodontitis, and discuss whether controlling the inflammation can influence the character and composition of the periodontal infection.

The Oral Microbiota Is Modified by Systemic Diseases

Periodontal diseases are initiated by bacteria that accumulate in a biofilm on the tooth surface and affect the adjacent periodontal tissue. Systemic diseases such as diabetes, rheumatoid arthritis (RA), and systemic lupus erythematosus (SLE) increase susceptibility to destructive periodontal diseases. In human studies and in animal models, these diseases have been shown to enhance inflammation in the periodontium and increase the risk or severity of periodontitis. All 3 systemic diseases are linked to a decrease in bacterial taxa associated with health and an increase in taxa associated with disease. Although there is controversy regarding the specific oral bacterial changes associated with each disease, it has been reported that diabetes increases the levels of Capnocytophaga, Porphyromonas, and Pseudomonas, while Prevotella and Selenomonas are increased in RA and Selenomonas, Leptotrichia, and Prevotella in SLE. In an animal model, diabetes increased the pathogenicity of the oral microbiome, as shown by increased inflammation, osteoclastogenesis, and periodontal bone loss when transferred to normal germ-free hosts. Moreover, in diabetic animals, the increased pathogenicity could be substantially reversed by inhibition of IL-17, indicating that host inflammation altered the microbial pathogenicity. Increased IL-17 has also been shown in SLE, RA, and leukocyte adhesion deficiency and may contribute to oral microbial changes in these diseases. Successful RA treatment with anti-inflammatory drugs partially reverses the oral microbial dysbiosis. Together, these data demonstrate that systemic diseases characterized by enhanced inflammation disturb the oral microbiota and point to IL-17 as key mediator in this process.

Systemic treatment with resveratrol reduces the progression of experimental periodontitis and arthritis in rats

Rheumatoid arthritis and periodontitis are chronic inflammatory diseases which has been closely associated due to the nature of immune-inflammatory imbalance response. Resveratrol is a naturall product with biological proprieties that may promote immunomodulatory effects on host response. This study investigated resveratrol continuous administration effect on experimental periodontitis and arthritis progression in rats. Thirty-five rats were assigned to the following groups: 1-experimental arthritis + experimental periodontitis + placebo (RA+EP +PL) (n = 12); 2 -RA+EP+ ibuprofen (RA+PE+IB) (n = 11); 3-RA+EP+ resveratrol (RA+PE+RSV) (n = 11). After euthanasia, the specimens were processed for morphometric analysis of bone loss, and the gingival tissue surrounding the first molar was collected for quantification of inflammatory markers using a Luminex/MAGpix assay and anti-citrullinated protein antibody (ACCPA) levels were measured by ELISA assay. Serum level of rheumatoid factor (RF) was measured by ELISA assay. Paw edema was analyzed using a plethysmometer. Higher bone loss was observed in PL group, when compared to IB and RSV groups. RSV group presented higher IL-4 concentration than PL and IB groups. Resveratrol reduced RF serum levels and both IB and RSV decreased ACCPA gingival levels. Besides, paw swelling level was significantly lower in IB and RSV groups in the 21th day and only in RSV group in the 28th day. Histological analyzes showed smooth articular surface and higher width of the subchondral cortical in RSV group. Resveratrol showed modulatory effect and seems to reduce the inflammatory signs of arthritis and articular damage throughout the time.

Gingival tissue, an extrasynovial source of malondialdehyde-acetaldehyde adducts, citrullinated and carbamylated proteins

BACKGROUND AND OBJECTIVE

Postranslational modification of proteins can lead to the production of autoantibodies and loss of immune tolerance. This process has been hypothesised to be a critical factor in the pathogenesis of rheumatoid arthritis. The objective of this study was to demonstrate that inflamed human gingival tissue provides an extrasynovial source of malondialdehyde-acetaldehyde adducts, citrullinated and carbamylated proteins all of which are considered to be linked to the development of rheumatoid arthritis. Identification of such modified proteins in inflamed gingiva may explain, in part, how inflammation of the periodontal tissues may influence the development of rheumatoid arthritis.

MATERIAL AND METHODS

Gingival biopsies of healthy, mild and moderate periodontitis were triple stained with antibodies against malondialdehyde-acetaldehyde adducts, citrullinated and carbamylated proteins.

RESULTS

Assessment of healthy gingival tissue revealed negligible staining for carbamylated, malondialdehyde-acetaldehyde (MAA), or citrullinated proteins. Mild periodontitis was positive for all three modifications. Furthermore, there was an increase in staining intensity for carbamylated, citrullinated and MAA-modified proteins in moderate periodontitis. Negative staining results were observed for the isotype controls.

CONCLUSION

This study provides evidence for the presence of citrullinated, carbamylated and MAA adduct modified proteins in inflamed periodontal tissues. The potential for these proteins to play a role in autoimmunity in a multi-system inflammatory syndromic disease model now needs to be determined.

Periodontitis increases rheumatic factor serum levels and citrullinated proteins in gingival tissues and alter cytokine balance in arthritic rats

This study investigated some immunological features by experimental periodontitis (EP) and rheumatoid arthritis (RA) disease interact in destructive processes in arthritic rats. Rats were assigned to the following groups: EP +RA; RA; EP; and Negative Control. RA was induced by immunizations with type-II collagen and a local immunization with Complete Freund's adjuvant in the paw. Periodontitis was induced by ligating the right first molars. The serum level of rheumatoid factor (RF) and anti-citrullinated protein antibody (ACCPA) were measured before the induction of EP (T1) and at 28 days after (T2) by ELISA assay. ACCPA levels were also measured in the gingival tissue at T2. The specimens were processed for morphometric analysis of bone loss, and the gingival tissue surrounding the first molar was collected for the quantification of interleukin IL-1β, IL-4, IL-6, IL-17 and TNF-α using a Luminex/MAGpix assay. Paw edema was analyzed using a plethysmometer. Periodontitis increased the RF and ACCPA levels in the serum and in the gingival tissue, respectively. Besides, the level of paw swelling was increased by EP and remained in progress until the end of the experiment, when EP was associated with RA. Greater values of IL-17 were observed only when RA was present, in spite of PE. It can be concluded that periodontitis increases rheumatic factor serum levels and citrullinated proteins level in gingival tissues and alter cytokine balance in arthritic rats; at the same time, arthritis increases periodontal destruction, confirming the bidirectional interaction between diseases.

Influence of periodontal treatment on rheumatoid arthritis: a systematic review and meta-analysis

OBJECTIVE

To evaluate the influence of periodontal treatment on rheumatoid arthritis activity.

METHODS

MEDLINE/PUBMED, The Cochrane Library, Clinical Trials, SciELO and LILACS were searched for studies published until December 2014. Included articles were: prospective studies; including patients older than 18 years, diagnosed with periodontitis and rheumatoid arthritis submitted to non-surgical periodontal treatment; with a control group receiving no periodontal treatment; with outcomes including at least one marker of rheumatoid arthritis activity. Methodological quality of the studies was assessed using PEDro scale. Quantitative data were pooled in statistical meta-analysis using Review Manager 5.

RESULTS

Four articles were included. Non-surgical periodontal treatment was associated with a significant reduction of DAS28 (OR: -1.18; 95% CI: -1.43, -0.93; p<0.00001). Erythrocyte sedimentation rate, C-reactive protein, patient's assessment of rheumatoid activity using visual analogical scale, tender and swollen joint counts showed a trend toward reduction (not statistically significant).

CONCLUSIONS

The reduction of DAS 28 in patients with rheumatoid arthritis after periodontal treatment suggests that the improvement of periodontal condition is beneficial to these patients. Further randomized controlled clinical trials are necessary to confirm this finding.

Influence of periodontal treatment on rheumatoid arthritis: a systematic review and meta-analysis

OBJECTIVE

To evaluate the influence of periodontal treatment on rheumatoid arthritis activity.

METHODS

MEDLINE/PUBMED, The Cochrane Library, Clinical Trials, SciELO and LILACS were searched for studies published until December 2014. Included articles were: prospective studies; including patients older than 18 years, diagnosed with periodontitis and rheumatoid arthritis submitted to non-surgical periodontal treatment; with a control group receiving no periodontal treatment; with outcomes including at least one marker of rheumatoid arthritis activity. Methodological quality of the studies was assessed using PEDro scale. Quantitative data were pooled in statistical meta-analysis using Review Manager 5.

RESULTS

Four articles were included. Non-surgical periodontal treatment was associated with a significant reduction of DAS28 (OR: -1.18; 95% CI: -1.43, -0.93; p <0.00001). Erythrocyte sedimentation rate, C-reactive protein, patient's assessment of rheumatoid activity using visual analogical scale, tender and swollen joint counts showed a trend towards reduction (not statistically significant).

CONCLUSIONS

The reduction of DAS 28 in patients with rheumatoid arthritis after periodontal treatment suggests that the improvement of periodontal condition is beneficial to these patients. Further randomized controlled clinical trials are necessary to confirm this finding.

Effects by periodontitis on pristane-induced arthritis in rats

Background

An infection-immune association of periodontal disease with rheumatoid arthritis has been suggested. This study aimed to investigate the effect of pre-existing periodontitis on the development and the immune/inflammatory response of pristane-induced arthritis.

Methods

We investigated the effect of periodontitis induced by ligature placement and Porphyromonas gingivalis (P. gingivalis) infection, in combination with Fusobacterium nucleatum to promote its colonization, on the development of pristane-induced arthritis (PIA) in rats (Dark Agouti). Disease progression and severity of periodontitis and arthritis was monitored using clinical assessment, micro-computed tomography (micro-CT)/intraoral radiographs, antibody response, the inflammatory markers such as α-1-acid glycoprotein (α-1-AGP) and c-reactive protein (CRP) as well as cytokine multiplex profiling at different time intervals after induction.

Results

Experimentally induced periodontitis manifested clinically (P < 0.05) prior to pristane injection and progressed steadily until the end of experiments (15 weeks), as compared to the non-ligated arthritis group. Injection of pristane 8 weeks after periodontitis-induction led to severe arthritis in all rats demonstrating that the severity of arthritis was not affected by the pre-existence of periodontitis. Endpoint analysis showed that 89% of the periodontitis-affected animals were positive for antibodies against arginine gingipain B and furthermore, the plasma antibody levels to a citrullinated P. gingivalis peptidylarginine deiminase (PPAD) peptide (denoted CPP3) were significantly (P < 0.05) higher in periodontitis rats with PIA. Additionally, there was a trend towards increased pro-inflammatory and anti-inflammatory cytokine levels, and increased α-1-AGP levels in plasma from periodontitis-challenged PIA rats.

Conclusions

Pre-existence of periodontitis induced antibodies against citrullinated peptide derived from PPAD in rats with PIA. However, there were no differences in the development or severity of PIA between periodontitis challenged and periodontitis free rats.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-016-1067-6) contains supplementary material, which is available to authorized users.

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.

Periodontitis and Rheumatoid Arthritis: What Do We Know?

BACKGROUND

Currently, in the field of rheumatology, there is much attention given towards the possible causality between periodontitis and rheumatoid arthritis (RA), specifically regarding the role of Porphyromonas gingivalis (Pg). This bacterium is unique, having a citrullinating enzyme. Antibodies against citrullinated proteins are rather specific for RA.

METHODS

Because causality is ultimately tested in longitudinal cohort studies which currently do not exist for periodontitis and RA, this commentary applied Bradford Hill criteria on the existing literature to assess causality as the most likely interpretation of this association.

CONCLUSIONS

From an epidemiologic point of view, patients with RA have a higher incidence of periodontal disease than individuals without RA. In addition, there is a dose-response pattern in the association between the severity of periodontitis and RA disease activity. There are indications that periodontitis precedes RA, but there is no evidence yet available to show that Pg plays a direct role in this temporal relationship. The role of the unique characteristic of citrullination by Pg remains unexplained. However, in animal models, citrullination by Pg plays a distinct role in the development and aggravation of experimental arthritis. Although the role of Pg in RA remains speculative, a causative role for periodontitis as a chronic inflammatory disease caused by infectious agents in RA seems biologically plausible.

Periodontitis: a host-mediated disruption of microbial homeostasis. Unlearning learned concepts

New concepts evolve when existing ones fail to address known factors adequately or are invalidated by new evidence. For decades periodontitis has been considered to be caused by specific bacteria or groups of bacteria and, accordingly, treatment protocols have largely been based on anti-infective therapies. However, close inspection of current data leads one to question whether these bacteria are the cause or the result of periodontitis. Good evidence is emerging to suggest that it is indeed the host response to oral bacteria that leads to the tissue changes noted in gingivitis. These changes lead to an altered subgingival environment that favors the emergence of 'periodontal pathogens' and the subsequent development of periodontitis if the genetic and external environmental conditions are favorable for disease development. Thus, it seems that it is indeed the initial early host-inflammatory and immune responses occurring during the development of gingivitis, and not specific bacteria or their so-called virulence factors, which determine whether periodontitis develops and progresses. In this review we consider these concepts and their potential to change the way in which we view and manage the inflammatory periodontal diseases.

Kartagener's syndrome and rheumatoid arthritis

We herein present the case of a 47-year-old woman with rheumatoid arthritis (RA) complicated by Kartagener's syndrome (KS). Although her RA disease activity score (DAS28-CRP) decreased following the administration of periodontitis treatment and etanercept, she did not achieve symptom relief or DAS28-CRP remission. After undergoing surgery for chronic sinusitis, her articular symptoms improved and the DAS28-CRP declined to the level of remission. Patients with KS may develop respiratory infections due to an impaired defense mechanism against microbes in the airway. Therefore, in patients with RA complicated by KS, comprehensive management of infection, including surgical therapy for sinusitis, is needed to reduce the RA disease activity.

Porphyromonas gingivalis oral infection exacerbates the development and severity of collagen-induced arthritis

INTRODUCTION

Clinical studies suggest a direct influence of periodontal disease (PD) on serum inflammatory markers and disease assessment of patients with established rheumatoid arthritis (RA). However, the influence of PD on arthritis development remains unclear. This investigation was undertaken to determine the contribution of chronic PD to immune activation and development of joint inflammation using the collagen-induced arthritis (CIA) model.

METHODS

DBA1/J mice orally infected with Porphyromonas gingivalis were administered with collagen II (CII) emulsified in complete Freund's adjuvant (CFA) or incomplete Freund's adjuvant (IFA) to induce arthritis. Arthritis development was assessed by visual scoring of paw swelling, caliper measurement of the paws, mRNA expression, paw micro-computed tomography (micro-CT) analysis, histology, and tartrate resistant acid phosphatase for osteoclast detection (TRAP)-positive immunohistochemistry. Serum and reactivated splenocytes were evaluated for cytokine expression.

RESULTS

Mice induced for PD and/or arthritis developed periodontal disease, shown by decreased alveolar bone and alteration of mRNA expression in gingival tissues and submandibular lymph nodes compared to vehicle. P. gingivalis oral infection increased paw swelling and osteoclast numbers in mice immunized with CFA/CII. Arthritis incidence and severity were increased by P. gingivalis in mice that received IFA/CII immunizations. Increased synovitis, bone erosions, and osteoclast numbers in the paws were observed following IFA/CII immunizations in mice infected with P gingivalis. Furthermore, cytokine analysis showed a trend toward increased serum Th17/Th1 ratios when P. gingivalis infection was present in mice receiving either CFA/CII or IFA/CII immunizations. Significant cytokine increases induced by P. gingivalis oral infection were mostly associated to Th17-related cytokines of reactivated splenic cells, including IL-1β, IL-6, and IL-22 in the CFA/CII group and IL-1β, tumor necrosis factor-α, transforming growth factor-β, IL-6 and IL-23 in the IFA/CII group.

CONCLUSIONS

Chronic P. gingivalis oral infection prior to arthritis induction increases the immune system activation favoring Th17 cell responses, and ultimately accelerating arthritis development. These results suggest that chronic oral infection may influence RA development mainly through activation of Th17-related pathways.

Periodontal disease and rheumatoid arthritis: the evidence accumulates for complex pathobiologic interactions

PURPOSE OF REVIEW

This review was conducted to focus on the recent clinical and translational research related to the associations between periodontal disease and rheumatoid arthritis.

RECENT FINDINGS

There is a growing interest in the associations between oral health and autoimmune and inflammatory diseases. A number of epidemiologic studies have described associations between rheumatoid arthritis and periodontal disease. Recent clinical studies continue to support these reports, and are increasingly linked with biological assessments to better understand the nature of these relationships. A number of recent studies have evaluated the periopathogenic roles of Porphyromonas gingivalis, the oral microbiome, and mechanisms of site-specific and substrate-specific citrullination. These are helping to further elucidate the interactions between these two inflammatory disease processes.

SUMMARY

Studies of clinical oral health parameters, the gingival microenvironment, autoantibodies and biomarkers, and rheumatoid arthritis disease activity measures are providing a better understanding of the potential mechanisms responsible for rheumatoid arthritis and periodontal disease associations. The cumulative results and ongoing studies have the promise to identify novel mechanisms and interventional strategies to improve patient outcomes for both conditions.

RNA interference-mediated silencing of Atp6i prevents both periapical bone erosion and inflammation in the mouse model of endodontic disease

Dental caries is one of the most prevalent infectious diseases in the United States, affecting approximately 80% of children and the majority of adults. Dental caries may lead to endodontic disease, where the bacterial infection progresses to the root canal system of the tooth, leading to periapical inflammation, bone erosion, severe pain, and tooth loss. Periapical inflammation may also exacerbate inflammation in other parts of the body. Although conventional clinical therapies for this disease are successful in approximately 80% of cases, there is still an urgent need for increased efficacy of treatment. In this study, we applied a novel gene-therapeutic approach using recombinant adeno-associated virus (AAV)-mediated Atp6i RNA interference (RNAi) knockdown of Atp6i/TIRC7 gene expression to simultaneously target periapical bone resorption and periapical inflammation. We found that Atp6i inhibition impaired osteoclast function in vitro and in vivo and decreased the number of T cells in the periapical lesion. Notably, AAV-mediated Atp6i/TIRC7 knockdown gene therapy reduced bacterial infection-stimulated bone resorption by 80% in the mouse model of endodontic disease. Importantly, Atp6i(+/-) mice with haploinsufficiency of Atp6i exhibited protection similar to that in mice with bacterial infection-stimulated bone erosion and periapical inflammation, which confirms the potential therapeutic effect of AAV-small hairpin RNA (shRNA)-Atp6i/TIRC7. Our results demonstrate that AAV-mediated Atp6i/TIRC7 knockdown in periapical tissues can inhibit endodontic disease development, bone resorption, and inflammation, indicating for the first time that this potential gene therapy may significantly improve the health of those who suffer from endodontic disease.

RNAi-mediated silencing of Atp6i and Atp6i haploinsufficiency prevents both bone loss and inflammation in a mouse model of periodontal disease

Periodontal disease affects about 80% of adults in America, and is characterized by oral bacterial infection-induced gingival inflammation, oral bone resorption, and tooth loss. Periodontitis is also associated with other diseases such as rheumatoid arthritis, diabetes, and heart disease. Although many efforts have been made to develop effective therapies for this disease, none have been very effective and there is still an urgent need for better treatments and preventative strategies. Herein we explored for the first time the possibility that adeno-associated virus (AAV)-mediated RNAi knockdown could be used to treat periodontal disease with improved efficacy. For this purpose, we used AAV-mediated RNAi knockdown of Atp6i/TIRC7 gene expression to target bone resorption and gingival inflammation simultaneously. Mice were infected with the oral pathogen Porphyromonas gingivalis W50 (P. gingivalis) in the maxillary periodontium to induce periodontitis. We found that Atp6i depletion impaired extracellular acidification and osteoclast-mediated bone resorption. Furthermore, local injection of AAV-shRNA-Atp6i/TIRC7 into the periodontal tissues in vivo protected mice from P. gingivalis infection-stimulated bone resorption by >85% and decreased the T-cell number in periodontal tissues. Notably, AAV-mediated Atp6i/TIRC7 knockdown also reduced the expression of osteoclast marker genes and inflammation-induced cytokine genes. Atp6i(+/-) mice with haploinsufficiency were similarly protected from P. gingivalis infection-stimulated bone loss and gingival inflammation. This suggests that AAV-shRNA-Atp6i/TIRC7 therapeutic treatment may significantly improve the health of millions who suffer from P. gingivalis-mediated periodontal disease.

Cardiovascular disease in autoimmune rheumatic diseases

Various autoimmune rheumatic diseases (ARDs), including rheumatoid arthritis, spondyloarthritis, vasculitis and systemic lupus erythematosus, are associated with premature atherosclerosis. However, premature atherosclerosis has not been uniformly observed in systemic sclerosis. Furthermore, although experimental models of atherosclerosis support the role of antiphospholipid antibodies in atherosclerosis, there is no clear evidence of premature atherosclerosis in antiphospholipid syndrome (APA). Ischemic events in APA are more likely to be caused by pro-thrombotic state than by enhanced atherosclerosis. Cardiovascular disease (CVD) in ARDs is caused by traditional and non-traditional risk factors. Besides other factors, inflammation and immunologic abnormalities, the quantity and quality of lipoproteins, hypertension, insulin resistance/hyperglycemia, obesity and underweight, presence of platelets bearing complement protein C4d, reduced number and function of endothelial progenitor cells, apoptosis of endothelial cells, epigenetic mechanisms, renal disease, periodontal disease, depression, hyperuricemia, hypothyroidism, sleep apnea and vitamin D deficiency may contribute to the premature CVD. Although most research has focused on systemic inflammation, vascular inflammation may play a crucial role in the premature CVD in ARDs. It may be involved in the development and destabilization of both atherosclerotic lesions and of aortic aneurysms (a known complication of ARDs). Inflammation in subintimal vascular and perivascular layers appears to frequently occur in CVD, with a higher frequency in ARD than in non-ARD patients. It is possible that this inflammation is caused by infections and/or autoimmunity, which might have consequences for treatment. Importantly, drugs targeting immunologic factors participating in the subintimal inflammation (e.g., T- and B-cells) might have a protective effect on CVD. Interestingly, vasa vasorum and cardiovascular adipose tissue may play an important role in atherogenesis. Inflammation and complement depositions in the vessel wall are likely to contribute to vascular stiffness. Based on biopsy findings, also inflammation in the myocardium and small vessels may contribute to premature CVD in ARDs (cardiac ischemia and heart failure). There is an enormous need for an improved CVD prevention in ARDs. Studies examining the effect of DMARDs/biologics on vascular inflammation and CV risk are warranted.

Periodontal disease and rheumatoid arthritis: a systematic review

This systematic review considers the evidence available for a relationship between periodontal disease and rheumatoid arthritis. MEDLINE/PubMed, CINAHL, DOSS, Embase, Scopus, Web of Knowledge, MedNar, and ProQuest Theses and Dissertations were searched from the inception of the database until June 2012 for any quantitative studies that examined the association between periodontal disease and rheumatoid arthritis. Nineteen studies met our inclusion criteria. Good evidence was found to support an association between these conditions with regard to tooth loss, clinical attachment levels, and erythrocyte sedimentation rates. Moderate evidence was noted for C-reactive protein and interleukin-1β. Some evidence for a positive outcome of periodontal treatment on the clinical features of rheumatoid arthritis was noted. These results provide moderate evidence based on biochemical markers and stronger evidence with regard to clinical parameters that common risk factors or common pathologic processes may be responsible for an association between rheumatoid arthritis and periodontal disease. Further studies are required to fully explore both the biochemical processes and clinical relationships between these 2 chronic inflammatory conditions. There is a need to move from case-control studies to more rigorous studies using well-defined populations and well-defined biochemical and clinical outcomes as the primary outcome measures with consideration of potential confounding factors.

Inhibiting periapical lesions through AAV-RNAi silencing of cathepsin K

Dental caries, one of the most prevalent infectious diseases worldwide, affects approximately 80% of children and the majority of adults. Dental caries may result in endodontic disease, leading to dental pulp necrosis, periapical inflammation and bone resorption, severe pain, and tooth loss. Periapical inflammation may also increase inflammation in other parts of the body. Although many studies have attempted to develop therapies for this disease, there is still an urgent need for effective treatments. In this study, we applied a novel gene therapeutic approach using recombinant adeno-associated virus (AAV)-mediated RNAi knockdown of Cathepsin K (Ctsk) gene expression, to target osteoclasts and periapical bone resorption in a mouse model. We found that AAV-sh-Cathepsin K (AAV-sh-Ctsk) impaired osteoclast function in vivo and furthermore reduced bacterial infection-stimulated bone resorption by 88%. Reduced periapical lesion size was accompanied by decreases in mononuclear leukocyte infiltration and inflammatory cytokine expression. Our study shows that AAV-RNAi silencing of Cathepsin K in periapical tissues can significantly reduce endodontic disease development, bone destruction, and inflammation in the periapical lesion. This is the first demonstration that AAV-mediated RNAi knockdown gene therapy may significantly reduce the severity of endodontic disease.

Expression of peptidylarginine deiminase-2 and -4, citrullinated proteins and anti-citrullinated protein antibodies in human gingiva

BACKGROUND AND OBJECTIVE

The presence of citrullinated proteins, and peptidylarginine deiminase types -2 (PAD-2) and -4 (PAD-4) in periodontal tissues, determine the presence of anti-cyclic citrullinated protein antibodies (anti-CCP) in gingival crevicular fluid (GCF) and compare the expression of these proteins between inflamed and non-inflamed sites.

MATERIAL AND METHODS

Tissue sections were stained using antibodies against citrullinated proteins, PAD-2 and PAD-4. RT-PCR was performed to investigate PAD-2 and PAD-4 mRNA in inflamed and non-inflamed gingival tissues. Anti-CCP antibodies in gingival crevicular fluid were detected by ELISA.

RESULTS

Citrullinated proteins, PAD-2 and PAD-4 were detected in gingiva. There was a correlation between inflammation and expression of these proteins. mRNAs for PAD-2 and PAD-4 were detected in both inflamed and non-inflamed gingival tissues. Antibodies to CCP were found mostly in the GCF of individuals with periodontitis.

CONCLUSION

PAD-2 and PAD-4 (protein and mRNA) as well as citrullinated proteins are present in inflamed gingiva, and anti-CCP antibodies can be detected in the GCF of some patients. Tissue expression of citrullinated proteins and PAD increased with the severity of inflammation. The presence of anti-CCP antibodies in GCF was almost exclusive to a subset of patients with periodontitis. Increased expression of these proteins in inflamed gingiva lends support to the notion that periodontal inflammation contributes to the inflammatory burden in a similar way to rheumatoid arthritis.

Advanced reconstructive technologies for periodontal tissue repair

Reconstructive therapies to promote the regeneration of lost periodontal support have been investigated through both preclinical and clinical studies. Advanced regenerative technologies using new barrier-membrane techniques, cell-growth-stimulating proteins or gene-delivery applications have entered the clinical arena. Wound-healing approaches using growth factors to target the restoration of tooth-supporting bone, periodontal ligament and cementum are shown to significantly advance the field of periodontal-regenerative medicine. Topical delivery of growth factors, such as platelet-derived growth factor, fibroblast growth factor or bone morphogenetic proteins, to periodontal wounds has demonstrated promising results. Future directions in the delivery of growth factors or other signaling models involve the development of innovative scaffolding matrices, cell therapy and gene transfer, and these issues are discussed in this paper.

Periodontitis, Porphyromonas, and the pathogenesis of rheumatoid arthritis

Epidemiological data indicate a link between rheumatoid arthritis (RA) and periodontal disease (PD). In vitro and in vivo studies have sought to dissect potential mechanisms by which PD may contribute to initiation and progression of RA. However, these are both multifactorial, chronic diseases, and their complex etiologies and pathogenesis themselves remain incompletely understood. Could there really be an etiological link or does this simply represent a statistical coincidence muddied by common risk factors? This review seeks to provide background on these two diseases in the context of recent discoveries suggesting that their pathogenesis may be related. In particular, the process of citrullination, a post-translational protein modification, has been highlighted as a process common to both diseases. The evidence for a relationship between the diseases is explored and its potential mechanisms discussed.

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.

Association between chronic periodontitis and rheumatoid arthritis: a hospital-based case-control study

Rheumatoid arthritis (RA) and chronic periodontitis are the most common chronic inflammatory diseases with remarkable pathological and clinical similarities. A lot of similarities exist between RA and periodontitis at cellular and molecular levels. The relationship between these two chronic inflammatory diseases is still unclear. This case-control study was undertaken to determine the possible association between chronic inflammatory diseases like RA and periodontitis. The case group consisted of 100 patients attending the Rheumatology clinic who have rheumatoid arthritis (RA group). Age- and gender-matched 112 patients without RA attending the Outpatient wing of Department of General Medicine formed the control group (NRA group). The number of missing teeth, gingival index (GI), oral hygiene index-simplified (OHI-S), probing pocket depth (PPD) and clinical attachment levels (CAL) were evaluated in both the groups. Rheumatoid disease activity was assessed by DAS-28 score system. Systemic markers of inflammation like erythrocytic sedimentation rate (ESR) and serum levels of C-reactive protein (CRP) were assessed. There was a statistically significant difference in GI, OHI-S, PPD, CAL, ESR and CRP levels between cases (RA group) and controls (NRA group) (P < 0.05). Among subjects with RA, there was no association between the rheumatoid disease activity and the severity of periodontal disease. The occurrence and severity of periodontitis was found to be higher in RA subjects as compared to subjects without RA, suggesting a positive relation between these two chronic inflammatory diseases.

Enhanced expression of tissue inhibitor of metalloproteinases-4 gene in human osteoarthritic synovial membranes and its differential regulation by cytokines in chondrocytes

Objective:

Tissue inhibitors of metalloproteinases (TIMPs) are multi-functional proteins with matrix metalloproteinases-inhibiting activities. We studied expression of anti-inflammatory, TIMP-4 gene in human joint tissues and its regulation by arthritis-associated cytokines.

Results:

TIMP-4 RNA expression originating from synovial fibroblasts was significantly (2.4 fold; p<0.001) elevated in 8 osteoarthritic (OA) versus 7 non-arthritic synovial membranes. Non-arthritic and OA femoral head and knee chondrocytes displayed substantial but variably constitutive expression of the TIMP-4 mRNA. In articular chondrocytes, transforming growth factor beta (TGF-β1) and oncostatin M (OSM) upregulated TIMP-4 RNA and protein expression while interleukin-1 (IL-1β) and tumor necrosis factor alpha (TNF-α) did not, suggesting differential regulation by arthritis-associated cytokines. Interleukin 17 (IL-17) mildly induced TIMP-4 mRNA. TGF-β1 induction of TIMP-4 expression was partly inhibited by ERK pathway and Sp1 transcription factor inhibitors.

Conclusion:

Enhanced TIMP-4 gene expression in OA synovial membranes and cartilage may be due to induction by TGF-β1, OSM and IL-17, suggesting its pathophysiological role in tissue remodeling in human joints. TGF-β1 induction of TIMP-4 expression is mediated partly by ERK pathway and Sp1 transcription factor.

Experimental arthritis triggers periodontal disease in mice: involvement of TNF-α and the oral Microbiota

Rheumatoid arthritis (RA) and periodontal disease (PD) are prevalent chronic inflammatory disorders that affect bone structures. Individuals with RA are more likely to experience PD, but how disease in joints could induce PD remains unknown. This study aimed to experimentally mimic clinical parameters of RA-induced PD and to provide mechanistic findings to explain this association. Chronic Ag-induced arthritis (AIA) was triggered by injection of methylated BSA in the knee joint of immunized mice. Anti-TNF-α was used to assess the role of this cytokine. Intra-articular challenge induced infiltration of cells, synovial hyperplasia, bone resorption, proteoglycan loss, and increased expression of cytokines exclusively in challenged joints. Simultaneously, AIA resulted in severe alveolar bone loss, migration of osteoclasts, and release of proinflammatory cytokines in maxillae. Anti-TNF-α therapy prevented the development of both AIA and PD. AIA did not modify bacterial counts in the oral cavity. PD, but not AIA, induced by injection of Ag in immunized mice was decreased by local treatment with antiseptic, which decreased the oral microbiota. AIA was associated with an increase in serum C-reactive protein levels and the expression of the transcription factors RORγ and Foxp3 in cervical lymph nodes. There were higher titers of anti-collagen I IgG, and splenocytes were more responsive to collagen I in AIA mice. In conclusion, AIA-induced PD was dependent on TNF-α and the oral microbiota. Moreover, PD was associated with changes in expression of lymphocyte transcription factors, presence of anti-collagen Abs, and increased reactivity to autoantigens.

Destructive and protective roles of cytokines in periodontitis: a re-appraisal from host defense and tissue destruction viewpoints

Periodontal diseases (PD) are chronic infectious inflammatory diseases characterized by the destruction of tooth-supporting structures, being the presence of periodontopathogens required, but not sufficient, for disease development. As a general rule, host inflammatory mediators have been associated with tissue destruction, while anti-inflammatory mediators counteract and attenuate disease progression. With the discovery of several T-cell subsets bearing distinct immunoregulatory properties, this pro- vs. anti-inflammatory scenario became more complex, and a series of studies has hypothesized protective or destructive roles for Th1, Th2, Th17, and Treg subpopulations of polarized lymphocytes. Interestingly, the "protective vs. destructive" archetype is usually considered in a framework related to tissue destruction and disease progression. However, it is important to remember that periodontal diseases are infectious inflammatory conditions, and recent studies have demonstrated that cytokines (TNF-α and IFN-γ) considered harmful in the context of tissue destruction play important roles in the control of periodontal infection. Therefore, in this review, the state-of-the-art knowledge concerning the protective and destructive roles of host inflammatory immune response will be critically evaluated and discussed from the tissue destruction and control-of-infection viewpoints.

Periodontitis and arthritis interaction in mice involves a shared hyper-inflammatory genotype and functional immunological interferences

Periodontitis (PD) and rheumatoid arthritis (RA) have been found to be clinically associated and to share the chronic nature of the inflammatory reaction associated with bone resorption activity. However, the mechanisms underlying such association are unknown. Therefore, we examined the basis of Actinobacillus actinomycetemcomitans- and Porphyromonas gingivalis-induced PD and pristane-induced arthritis (PIA) interaction in mice. Higher severity PD in the genetically inflammation prone acute inflammatory reactivity maximum (AIRmax) mice strain was associated with higher levels of TNF-alpha, IL-1beta, IL-17, matrix metalloproteinase (MMP)-13, and RANKL, whereas PD/PIA co-induction resulted in even higher levels of IL-1beta, IFN-gamma, IL-17, RANKL, and MMP-13 levels. Conversely, PD/PIA co-induction in AIRmin strain did not alter the course of both pathologies. PIA/PD co-induction resulted in altered expression of T-cell subsets transcription factors expression, with T-bet and RORgamma levels being upregulated, whereas GATA-3 levels were unaltered. Interestingly, PIA induction resulted in alveolar bone loss, such response being highly dependent on the presence of commensal oral bacteria. No differences were found in PIA severity parameters by PD co-induction. Our results show that the interaction between experimental PD and arthritis in mice involves a shared hyper-inflammatory genotype and functional interferences in innate and adaptive immune responses.

Periodontal therapy reduces the severity of active rheumatoid arthritis in patients treated with or without tumor necrosis factor inhibitors

BACKGROUND

Rheumatoid arthritis (RA) and periodontitis are common chronic inflammatory conditions. Recent studies showed a beneficial effect of periodontal treatment on the severity of active RA. This study was undertaken to further examine the effect of non-surgical periodontal treatment on the signs and symptoms of RA in patients treated with or without anti-tumor necrosis factor-alpha (anti-TNF-alpha) medications. The effect of anti-TNF-alpha therapy on periodontitis also was assessed.

METHODS

Forty participants diagnosed with moderate/severe RA (under treatment for RA) and severe periodontitis were randomly assigned to receive initial non-surgical periodontal therapy with scaling/root planing and oral hygiene instructions (n = 20) or no periodontal therapy (n = 20). To control RA, all participants had been using disease-modifying anti-rheumatic drugs, and 20 had also been using anti-TNF-alpha before randomization. Probing depth (PD), clinical attachment level (CAL), bleeding on probing (BOP), gingival index (GI), plaque index (PI), RA disease activity score 28 (DAS28), and erythrocyte sedimentation rate (ESR) were measured at baseline and 6 weeks later. Linear mixed models were used to identify significant differences between subjects who received periodontal treatment and those who did not.

RESULTS

Patients receiving periodontal treatment showed a significant decrease in the mean DAS28, ESR (P <0.001), and serum TNF-alpha (P <0.05). There was no statistically significant decrease in these parameters in patients not receiving periodontal treatment. Anti-TNF-alpha therapy resulted in a significant improvement in CAL, PD, BOP, and GI.

CONCLUSIONS

Non-surgical periodontal therapy had a beneficial effect on the signs and symptoms of RA, regardless of the medications used to treat this condition. Anti-TNF-alpha therapy without periodontal treatment had no significant effect on the periodontal condition.

Periodontitis in systemic rheumatic diseases

Periodontitis is a chronic inflammatory disease that is characterized by loss of the periodontal ligament and alveolar bone, and is a major cause of tooth loss. Results from clinical and epidemiologic studies have suggested that periodontitis and tooth loss are more prevalent in individuals with rheumatoid arthritis (RA). However, the strength and temporality of the association are uncertain. Several biologically plausible causal and noncausal mechanisms might account for this association between periodontitis and RA. There is evidence to suggest that periodontitis could indeed be a causal factor in the initiation and maintenance of the autoimmune inflammatory response that occurs in RA. If proven, chronic periodontitis might represent an important modifiable risk factor for RA. In addition, patients with RA might show an increased risk of developing periodontitis and tooth loss through various mechanisms. Moreover, exposure to common genetic, environmental or behavioral factors might contribute to a noncausal association between both conditions.