Viruses in periodontal disease - a review

A Low-Cost Protocol Using the Adjunctive Action of Povidone-Iodine Irrigations and Sodium Hypochlorite Rinsing Solution in Step 2 of Periodontal Therapy for Patients with Stage III-IV Periodontitis: A Single-Blind, Randomized Controlled Trial

In severe stages of periodontitis, conventional periodontal therapy and maintenance care are usually insufficient due to the viral and bacterial etiology; thus, a mechanical approach alone may not be sufficient to eliminate a substantial portion of subgingival pathogens, especially in deep periodontal sites. Background and Objectives: This single-blind, randomized clinical trial aimed to compare the clinical and microbiological efficacy of a low-cost protocol using povidone-iodine and sodium hypochlorite formulations as adjuncts to non-surgical therapy for patients with stage IV periodontitis when compared with chlorhexidine, the most commonly employed substance to date for antimicrobial regimens in periodontal therapy. Materials and Methods: Forty-five patients were randomly divided into two groups: control (subgingival instrumentation, chlorhexidine-assisted) and test (antiviral medication, subgingival instrumentation with povidone-iodine, sodium hypochlorite rinsing solution, and antibiotics). Clinical measurements and microbiological analyses were performed at baseline and after three months. Results: After three months, notable differences were found in the bacterial detection scores for Porphyromonas gingivalis (a significant reduction in detection frequency was observed in the test compared to the control (p = 0.021)), and there were significant reductions in detection in the test group for Tannerella forsythia and Treponema denticola, showing undetectable levels (p < 0.0001 for both). In the test group, the pocket probing depth median value was reduced significantly (p = 0.0005); similarly, bleeding on probing showed a marked decrease (p < 0.0001). However, changes in clinical attachment loss and full-mouth plaque score were not statistically significant. Conclusions: Using the proposed protocol, substantial improvements in clinical and microbiological parameters were obtained when compared with the current antimicrobial recommendations.

Association of Herpesvirus and Periodontitis: A Clinical and Laboratorial Case-Control Study

OBJECTIVES

 A significant influence of the Herpesviridae family in the progression of periodontal disease has been suggested. The aim of this study was to investigate the potential association of four Herpesviruses (HSV-1, HSV-2, cytomegalovirus [CMV], and Epstein-Barr virus [EBV]) with periodontal disease using a qualitative test for evaluating the presence or absence of viral DNA in crevicular fluid samples of both healthy periodontal patients and periodontal compromised patients.

MATERIALS AND METHODS

 A case-control study was conducted in 100 participants at a university clinic. A qualitative test was used for evaluating the presence/absence of viral DNA in crevicular fluid samples of both healthy periodontal patients and periodontal compromised patients, and considering the periodontitis staging (stage II, stage III, and stage IV) and grading (grade A, grade B, and grade C).

STATISTICAL ANALYSIS

 The distribution of the same exposure variables to the periodontitis staging and grading was compared using Chi-square, Fisher's exact, and Gamma tests depending on the variable characteristics. The significance level was set at 5%. The association of the variables: age, sex, diabetes, smoking, alcohol, and oral hygiene was also considered.

RESULTS

 The prevalence of Herpesviridae family virus DNA was 6% for the periodontal healthy group and 60% for the periodontitis group (roughly 60% on periodontitis stages II, III, and IV, p <0.001; and twofold increase in moderate and rapid progression grades compared with the slow progression grade, p <0.001). HSV1 DNA was prevalent in all periodontitis stages and grades. HSV 2, EBV, and CMV DNA had increasing prevalence rates in more severe stages (stages III and IV, p <0.001); while considering periodontitis grade, HSV2 (p = 0.001), CMV (p = 0.019) and EBV (p <0.001) DNA were prevalent only in grades B and C, with EBV DNA registering a marked prevalence in grade C.

CONCLUSION

 A significant different distribution of Herpesviridae virus DNA per each stage of disease was registered.

TLR3 recognition of viral double-stranded RNA in human dental pulp cells is important for the innate immunity

Dental caries or trauma can expose human dental pulp cells (DPCs) to various oral microorganisms, which play an important role in the development of an innate immune response. In the present study, we examined the expression of Toll-like receptors (TLRs) for sensing microbe-associated molecular patterns in human DPCs. Interestingly, real-time PCR analysis demonstrated that TLR3 is the most highly expressed among 10 different TLRs in human DPCs. Poly(I:C), a representative TLR3 ligand mimicking viral double-stranded RNA, potently induced IL-8 expression in a time- and dose-dependent manner. Concordantly, poly(I:C) treatment substantially increased the expression of pro-inflammatory cytokines and chemokines such as IL-6, CCL2, and CXCL10. Human DPCs transfected with TLR3 siRNA exhibited decreased IL-8 production compared with non-targeting siRNA-transfected cells, suggesting that the expression of poly(I:C)-induced inflammatory cytokines is dependent on TLR3. IL-8 secretion induced by poly(I:C) was down-regulated by MAP kinase inhibitors, indicating that the MAP kinase pathway contributes to IL-8 production. Furthermore, C/EBPβ and NF-κB were essential transcriptional factors for poly(I:C)-induced IL-8 expression, as demonstrated by the transient transfection and reporter gene assay. Since lipoproteins are known as major immunostimulatory components of bacteria, human DPCs were treated with poly(I:C) together with Pam2CSK4, a synthetic lipopeptide mimicking bacterial lipoproteins. Pam2CSK4 and poly(I:C) co-treatment synergistically increased IL-8 production in comparison to Pam2CSK4 or poly(I:C) alone, implying that co-infection of viruses and bacteria can synergistically induce inflammatory responses in the dental pulp. Taken together, these results suggest that human DPCs potentially sense and respond to viral double-stranded RNAs, leading to effective induction of innate immune responses.

The enigmatic roles of Anelloviridae and Redondoviridae in humans

Anelloviridae and Redondoviridae are virus families with small, circular, single-stranded DNA genomes that are common components of the human virome. Despite their small genome size of less than 5000 bases, they are remarkably successful - anelloviruses colonize over 90% of adult humans, while the recently discovered redondoviruses have been found at up to 80% prevalence in some populations. Anelloviruses are present in blood and many organs, while redondoviruses are found mainly in the ororespiratory tract. Despite their high prevalence, little is known about their biology or pathogenic potential. In this review, we discuss anelloviruses and redondoviruses and explore their enigmatic roles in human health and disease.

Future Drug Targets in Periodontal Personalised Medicine-A Narrative Review

Periodontal disease is an infection-driven inflammatory disease characterized by the destruction of tooth-supporting tissues. The establishment of chronic inflammation will result in progressive destruction of bone and soft tissue changes. Severe periodontitis can lead to tooth loss. The disease has complex pathogenesis with an interplay between genetic, environmental, and host factors and pathogens. Effective management consists of plaque control and non-surgical interventions, along with adjuvant strategies to control inflammation and disrupt the pathogenic subgingival biofilms. Recent studies have examined novel approaches for managing periodontal diseases such as modulating microbial signaling mechanisms, tissue engineering, and molecular targeting of host inflammatory substances. Mounting evidence suggests the need to integrate omics-based approaches with traditional therapy to address the disease. This article discusses the various evolving and future drug targets, including proteomics, gene therapeutics, vaccines, and nanotechnology in personalized periodontal medicine for the effective management of periodontal diseases.

Nature of the Interplay Between Periodontal Diseases and COVID-19

The coronavirus disease 2019 (COVID-19) is mostly a mild condition, however, in some patients, it could progress into a severe and even fatal disease. Recent studies have shown that COVID-19 infection and severity could be associated with the presence of periodontitis, one of the most prevalent chronic diseases. This association could be explained by the fact that periodontitis and COVID-19 share some common risk factors that included chronic diseases, such as diabetes and hypertension as well as conditions such as age, sex, and genetic variants. Another possible explanation could be the systemic inflammation and the aspiration of periodontopathogens seen in patients with periodontitis, which could have a synergism with the virus or compromise the reaction of the body against COVID-19. This narrative review explores the nature of these associations, the evidence behind them, and their implications.

Human Cytomegalovirus Replication and Infection-Induced Syncytia Formation in Labial, Foreskin, and Fetal Lung Fibroblasts

Only a handful of cell types, including fibroblasts, epithelial, and endothelial cells, can support human cytomegalovirus (CMV) replication in vitro, in striking contrast to the situation in vivo. While the susceptibility of epithelial and endothelial cells to CMV infection is strongly modulated by their anatomical site of origin, multiple CMV strains have been successfully isolated and propagated on fibroblasts derived from different organs. As oral mucosal cells are likely involved in CMV acquisition, we sought to evaluate the ability of infant labial fibroblasts to support CMV replication, compared to that of commonly used foreskin and fetal lung fibroblasts. No differences were found in the proportion of cells initiating infection, or in the amounts of viral progeny produced after exposure to the fibroblast-adapted CMV strain AD169 or to the endothelial cell-adapted strain TB40/E. Syncytia formation was, however, significantly enhanced in infected labial and lung fibroblasts compared to foreskin-derived cells, and did not occur after infection with AD169. Together, these data indicate that fibroblast populations derived from different tissues are uniformly permissive to CMV infection but retain phenotypic differences of potential importance for infection-induced cell-cell fusion, and ensuing viral spread and pathogenesis in different organs.

COVID-19 manifestation in the oral cavity - a narrative literature review

COVID-19 is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a recently discovered coronavirus, which in 2020 led to a global pandemic. Clinical manifestations of COVID-19 are very diverse and symptoms range from mild to severe. Correlated symptoms might also manifest in the oral cavity, which is a potential pathway for viral infection, and therefore might be a potential pathway for SARS-CoV-2. In recent research among patients with SARS-CoV-2 infection, taste and olfactory disorders, dry mouth, drones and inflammation of mouth, bitter taste in mouth, difficulty in swallowing and burning sensations have been reported. There have been cases of oral mucosal lesions in patients diagnosed with COVID-19 disease. Some correlations between periodontitis and severity of COVID-19 disease have also been observed. Oral mucosa, due to occurrence of ACE2 receptors, is highly susceptible to SARS-CoV-2 infection. The occurrence of changes on oral mucosa should increase the alertness of dental practitioners. However, knowledge in this area is still limited and in the field of oral manifestations of COVID-19 more research and patient observations are required.

Epstein-Barr Virus in Salivary Samples from Systemic Lupus Erythematosus Patients with Oral Lesions

In order to investigate the possible role of Epstein-Barr virus (EBV) in systemic lupus erythematosus (SLE) and its associated oral lesions, a pilot case-control study was performed. A total of 31 patients (18 females and 13 males) were enrolled in the study and divided into two groups: group A included 16 patients with diagnosis of SLE and group B included 15 healthy individuals. Salivary swab samples were collected and subjected to molecular screening by real-time quantitative PCR (qPCR) for the detection of EBV DNA. EBV DNA was significantly detected in 8/16 (50%) SLE patients and in 5/7 (71.4%) subjects with SLE-associated oral lesions. Since EBV is one of the most common viruses in the human population, it is difficult to understand if it is the causative agent of SLE or, vice versa, if SLE is able to trigger the reactivation of EBV. This study highlights a significant association between the presence of EBV and both SLE and SLE-related oral lesions and provides rationale for further investigation into the role of EBV in SLE pathogenesis.

Human herpesvirus DNA occurrence in intracranial aneurysmal wall: illustrative case

BACKGROUND

Subarachnoid hemorrhages secondary to intracranial aneurysms (IAs) are events of high mortality. These neurological vascular diseases arise from local and systemic inflammation that culminates in vessel wall changes. They may also have a possible relationship with chronic viral infections, such as human herpesvirus (HHV), and especially Epstein–Barr virus (EBV), which causes several medical conditions. This is the first description of the presence of HHV deoxyribonucleic acid (DNA) in a patient with IA.

OBSERVATIONS

A 61-year-old woman with a downgraded level of consciousness underwent radiological examinations that identified a 10-mm ruptured aneurysm in the anterior communicating artery. A microsurgery clip was performed to definitively treat the aneurysm and occurred without surgical complications. Molecular analysis of the material obtained revealed the presence of EBV DNA in the aneurysm wall. The patient died 21 days after admission due to clinical complications and brain swelling.

LESSONS

This is the first description of the presence of herpesvirus DNA in a patient with IA, presented in 2.8% of our data. These findings highlight that viral infection may contribute to the pathophysiology and is an additional risk factor for IA formation, progression, and rupture by modulating vessel wall inflammation and structural changes in chronic infections.

Dysregulation of metallothionein and zinc aggravates periodontal diseases

BACKGROUND

Periodontitis (PD) is a multifaceted inflammatory disease connected to bacterial infection that results in the destruction of tooth supporting structures and eventually tooth loss. Given their involvement in infection and inflammation, both metallothionein (MT) and zinc (Zn) might play vital roles in the development and progression of PD. More specifically, both MT and Zn are heavily involved in regulating immune functions, controlling bacterial infection, balancing inflammatory responses, and reducing oxidative stress, all of which are associated with the pathogenesis of PD.

OBJECTIVE

This review paper will explore the physiological functions of MT and Zn and hypothesise how dysregulation could negatively affect periodontal health, leading to PD.

FINDINGS

Bacterial lipopolysaccharide (LPS) derived from periodontal pathogens, namely P. gingivalis initiates the acute phase response, thus upregulating the expression of MT which leads to the subsequent deficiency of Zn, a hallmark of periodontal disease. This deficiency leads to ineffective NETosis, increases the permeability of the gingival epithelium, and disrupts the humoral immune response, collectively contributing to PD. In addition, the presence of LPS in Zn deficient conditions favours M1 macrophage polarisation and maturation of dendritic cells, and also inhibits the anti-inflammatory activity of regulatory T cells. Collectively, these observations could theoretically give rise to the chronic inflammation seen in PD.

CONCLUSION

A disrupted MT and Zn homeostasis is expected to exert an adverse impact on periodontal health and contribute to the development and progression of PD.

Phenotypic and Functional Alterations of Immune Effectors in Periodontitis; A Multifactorial and Complex Oral Disease

Survival and function of immune subsets in the oral blood, peripheral blood and gingival tissues of patients with periodontal disease and healthy controls were assessed. NK and CD8 + T cells within the oral blood mononuclear cells (OBMCs) expressed significantly higher levels of CD69 in patients with periodontal disease compared to those from healthy controls. Similarly, TNF-α release was higher from oral blood of patients with periodontal disease when compared to healthy controls. Increased activation induced cell death of peripheral blood mononuclear cells (PBMCs) but not OBMCs from patients with periodontal disease was observed when compared to those from healthy individuals. Unlike those from healthy individuals, OBMC-derived supernatants from periodontitis patients exhibited decreased ability to induce secretion of IFN-γ by allogeneic healthy PBMCs treated with IL-2, while they triggered significant levels of TNF-α, IL-1β and IL-6 by untreated PBMCs. Interaction of PBMCs, or NK cells with intact or NFκB knock down oral epithelial cells in the presence of a periodontal pathogen, F. nucleatum, significantly induced a number of pro-inflammatory cytokines including IFN-γ. These studies indicated that the relative numbers of immune subsets obtained from peripheral blood may not represent the composition of the immune cells in the oral environment, and that orally-derived immune effectors may differ in survival and function from those of peripheral blood.

Periodontal tissues are targets for Sars-Cov-2: a post-mortem study

Background: The ability of coronavirus SARS-CoV-2 to spread is one of the determinants of the COVID-19 pandemic status. Until June 2020, global COVID-19 cases surpassed 10 million. Asymptomatic patients, with no respiratory impairment, are believed to be responsible for more than 80% of the transmission. Other viruses have been consistently detected in periodontal tissues. Objective: The aim of this study was to investigate the presence of SARS-CoV-2 in periodontal tissue. Methods: We conducted video-endoscope minimally invasive post-mortem biopsy in seven fatal cases of COVID-19, using a regular endoscope video system associated with a smartphone to locate periodontal tissue. We analyzed the samples using RT-PCR, to identify the SARS-CoV-2 RNA and histopathological analysis. Results: The seven studied autopsies with positive laboratory tests for COVID-19 included 57.14% of female patients at the average age of 47.4 (range 8 to 74). In five cases, periodontal tissue was positive for SARS-CoV-2 (RT-PCR). Histopathologic analyses showed morphologic alterations in the keratinocytes of the junctional epithelium, a vacuolization of the cytoplasm and nucleus and nuclear pleomorphism. Conclusion: We presented a biomolecular analysis obtained from minimally invasive autopsies. This is the first study to demonstrate the presence of SARS-CoV-2 in periodontal tissue in COVID-19 positive patients.

Periodontal pockets: A potential reservoir for SARS-CoV-2?

Periodontal pockets are the major clinical manifestation of Periodontitis, a chronic inflammatory oral disease affecting the teeth-supporting tissues and has high prevalence in the adult population. Periodontal pockets are ideal environments for subgingival bacterial biofilms, that interact with the supragingival oral cavity, mucosal tissues of the pocket and a peripheral circulatory system. Periodontal pockets have been found to harbor viral species such as the Herpes simplex viruses' family. Recently, the SARS-CoV-2 has gained major interest of the scientific/medical community as it caused a global pandemic (Covid-19) and paralyzed the globe with high figures of infected people worldwide. This virus behavior is still partially understood, and by analyzing some of its features we hypothesized that periodontal pocket could be a favorable anatomical niche for the virus and thus acting as a reservoir for SARS-CoV-2.

Evidence linking the role of periodontal viruses in coronary artery disease with and without periodontitis

BACKGROUND

Viruses are considered to be a newer family associated with inflammatory diseases. Yet the role of periodontal viruses in coronary artery diseases (CAD) remains unclear. Thus, the current study aims to evaluate the prevalence of periodontal viruses and compare the same in cardiac samples of CAD patients with and without periodontitis.

METHODS

A total of 60 patients with CAD indicated for coronary artery bypass graft surgery (CABG) were included. These were grouped into 36 patients with healthy periodontium (CAD only) and 24 patients with periodontitis (CAD + P). The demographic variables, cardiac parameters and periodontal parameters were recorded. Cardiac tissue samples were collected during the CABG surgery and were analyzed by reverse transcriptase polymerase chain reaction for periodontal viruses such as Epstein-Barr virus (EBV), cytomegalovirus (CMV) and Herpes simplex virus. All the parameters were statistically analyzed.

RESULTS

Among the demographic variables, age was statistically significant between the groups. Plaque index, bleeding index, probing depth, and clinical attachment level (CAL) were significantly higher in CAD+P group (P ˂0.05). Periodontal viruses such as EBV and CMV were significantly higher (62.5% and 75% respectively, P ˂0.05) in the cardiac samples of the CAD+P than CAD only (25% and 47.2%, respectively). A significant association between EBV and CAL was revealed by multiple logistic regression analysis. (B = 0.374, P = 0.046) CONCLUSIONS: The results revealed a higher prevalence of periodontal viruses such as EBV and CMV in CAD patients with periodontitis suggesting it as one of the risk factors for CAD. This is supported by the fact that severity of periodontal disease (CAL) is associated with the presence of EBV in coronary artery plaque samples in the current study.

Salivary markers of oxidative stress and periodontal pathogens in patients with periodontitis from Santander, Colombia

Introduction:

Periodontitis affects more than 20% of the Latin American population. Oxidative markers are associated with greater progression of periodontitis; therefore, its role in pathogenesis should be studied.

Objective:

To determine the prevalence of the main oral bacteria and viruses associated with periodontitis and estimate the total antioxidant capacity and lipid peroxidation in saliva from patients with periodontitis.

Materials and methods:

We conducted systemically a cross-sectional study in 101 healthy subjects, 87 of whom had been diagnosed with periodontitis (P), according to the criteria of the Centers of Disease Control and Prevention and the American Academy of Periodontology, and 14 without periodontal pockets as controls (C). In subgingival samples, major viruses and dental pathogenic bacteria were identified using PCR techniques. The levels of total antioxidant capacity and malon-di-aldehyde (MDA) were determined by spectrophotometry in samples of unstimulated saliva.

Results:

The mean of periodontal depth pocket and clinical attachment loss in patients with periodontitis was 5.6 ± 1.7 and 6.1 ± 3.1 mm, respectively. The most prevalent microorganisms were Aggregatibacter actinomycetemcomitans (32.5%) and Porphyromonas gingivalis (18.6%). The patients from rural areas showed a higher percentage of A. actinomycetemcomitans (urban: 17.9% vs. rural: 48.9%, p=0.0018). In patients with periodontitis, the frequency of EBV, HSV1 & 2, and HCMV genes was 2.3%. Periodontitis patients had higher levels of MDA (P: 2.1 ± 1.5; C: 0.46 ± 0.3 µmol/g protein; p=0.0001) and total antioxidant capacity (P: 0.32 ± 0.2; C: 0.15 ± 0.1 mM; p< 0.0036). Oxidative markers showed no modifications due to the presence of periodontopathic bacteria.

Conclusions:

Aggregatibacter actinomycetemcomitans was the most prevalent bacteria; its presence did not modify the levels of oxidative markers in the saliva of patients with periodontitis.

mRNA expression of IFN-λs in the gingival tissue of patients with chronic or aggressive periodontitis: A polymerase chain reaction study

BACKGROUND

Several studies have proven the existence of herpesviruses in periodontal pockets of patients with chronic or aggressive periodontitis. Recently discovered interferon lambda (IFN-λ) has antiviral properties and is induced by herpesviruses. The present study was a quantitative analysis of messenger RNA (mRNA) expression of IFN-λs (IFN-λ1, IFN-λ2, IFN-λ3) in the gingival tissues of patients with chronic or aggressive periodontitis.

METHODS

A total of 90 participants (50 men and 40 women; age range 19-50 years, mean age 31.50 ± 7.8) were categorized into three groups: healthy participants, patients with chronic periodontitis, and patients with aggressive periodontitis. mRNA expression of IFN-λs in gingival tissues was estimated using reverse transcriptase polymerase chain reaction and was correlated with clinical parameters such as gingival index (GI), probing pocket depth (PPD), and clinical attachment level (CAL).

RESULTS

mRNA of IFN-λ1, IFN-λ2, and IFN-λ3 was expressed in gingival tissues of healthy participants and in patients with chronic or aggressive periodontitis. The highest level of IFN-λ1 was observed in patients with aggressive periodontitis (3.049 ± 9.793), whereas IFN-λ2 (4.322 ± 11.310) and IFN-λ3 (11.932 ± 27.479) were highest in patients with chronic periodontitis. The difference in mRNA expression of IFN-λ1 (P = 0.008) and IFN-λ3 (P = 0.043) among three groups was statistically significant CONCLUSION: Increased quantity of IFN-λs in patients with chronic and patients with aggressive periodontitis suggests a role in periodontitis. Variation in the expression of IFN-λ1 and IFN-λ3 in patients with periodontitis needs to be further evaluated. The mRNA expression of antiviral IFN-λs in gingival tissues might enhance our understanding related to viral pathogenesis of periodontal diseases.

Redondoviridae, a Family of Small, Circular DNA Viruses of the Human Oro-Respiratory Tract Associated with Periodontitis and Critical Illness

The global virome is largely uncharacterized but is now being unveiled by metagenomic DNA sequencing. Exploring the human respiratory virome, in particular, can provide insights into oro-respiratory diseases. Here, we use metagenomics to identify a family of small circular DNA viruses-named Redondoviridae-associated with human diseases. We first identified two redondovirus genomes from bronchoalveolar lavage samples from human lung donors. We then queried thousands of metagenomic samples and recovered 17 additional complete redondovirus genomes. Detections were exclusively in human samples and mostly from respiratory tract and oro-pharyngeal sites, where Redondoviridae was the second most prevalent eukaryotic DNA virus family. Redondovirus sequences were associated with periodontal disease, and abundances decreased with treatment. Some critically ill patients in a medical intensive care unit were found to harbor high levels of redondoviruses in respiratory samples. These results suggest that redondoviruses colonize human oro-respiratory sites and can bloom in several human disorders.

IFN-β secretion is through TLR3 but not TLR4 in human gingival epithelial cells

The oral cavity is home for a plethora of bacteria and viruses. Epithelial barriers encounter these micro-organisms and recognize them via pathogen recognition receptors (PRRs) that instigate antibacterial and antiviral responses. We and others have shown that human gingival epithelial cells (HGECs) express PRRs to defend invading pathogens. Among these PRRs, TLR2, TLR3 and TLR4 are highly expressed in HGECs and appear to be important based on our previous findings. IFN-β is one of the major type 1 interferons induced to defend viral attack. In this report, we sought to dissect TLR3 and TLR4 mediated secretion of IFN-β in HGECs. We stimulated HGECs with ultrapure LPS (TLR4 ligand) and Poly I:C (TLR3 ligand) for 24 h and supernatant was used to determine IFN-β secretion. We show that cells treated with Poly I:C induced IFN-β secretion but not cells treated with LPS. In addition, silencing of TLR3 prior to Poly I:C stimulation significantly downregulated IFN-β secretion. On the contrary, overexpression of MD2 and TLR4 in HGECs restored IFN-β secretion. Upon further evaluation, we found that TLR3 stimulation but not TLR4 induced the phosphorylation of interferon regulatory factor 3 (IRF3), which is critical for IFN-β secretion. We conclude that IFN-β secretion is through TLR3 and not via TLR4 in HGECs.

Specific clones of Trichomonas tenax are associated with periodontitis

Trichomonas tenax, an anaerobic protist difficult to cultivate with an unreliable molecular identification, has been suspected of involvement in periodontitis, a multifactorial inflammatory dental disease affecting the soft tissue and bone of periodontium. A cohort of 106 periodontitis patients classified by stages of severity and 85 healthy adult control patients was constituted. An efficient culture protocol, a new identification tool by real-time qPCR of T. tenax and a Multi-Locus Sequence Typing system (MLST) based on T. tenax NIH4 reference strain were created. Fifty-three strains of Trichomonas sp. were obtained from periodontal samples. 37/106 (34.90%) T. tenax from patients with periodontitis and 16/85 (18.80%°) T. tenax from control patients were detected by culture (p = 0.018). Sixty of the 191 samples were tested positive for T. tenax by qPCR, 24/85 (28%) controls and 36/106 (34%) periodontitis patients (p = 0.089). By combining both results, 45/106 (42.5%) patients were positive by culture and/or PCR, as compared to 24/85 (28.2%) controls (p = 0.042). A link was established between the carriage in patients of Trichomonas tenax and the severity of the disease. Genotyping demonstrates the presence of strain diversity with three major different clusters and a relation between disease strains and the periodontitis severity (p<0.05). More frequently detected in periodontal cases, T. tenax is likely to be related to the onset or/and evolution of periodontal diseases.

HLA-B57.01 shields people living with HIV for significantly better periodontal health

BACKGROUND

To assess the association between HLA-B57.01 (Human leukocyte antigen) and clinical parameters of chronic periodontitis in people living with HIV (PLWHIV).

METHODS

All patients were recruited from the HIVCENTER at the University Hospital Frankfurt during April 2014 and July 2015. Periodontal examination included Periodontal Screening Index (PSI), Gingivalindex (GI), Bleeding on Probing Index (BOP), Periodontal Probing Depth (PD), Clinical Attachment Level (CAL) and DMF-T Score (decayed, missing, filled teeth). Associations among periodontitis, HLA-system and additional risk factors in PLWHIV were evaluated in multivariate analyses.

RESULTS

One hundred PLWHIV were enrolled. Forty-five patients were naive, meaning that these patients never took antiretroviral (ARV) drugs before, 55 patients treated with combined antiretroviral therapy (cART). Nineteen patients presented a positive HLA-B 57.01 status. PLWHIV who were carriers of HLA-B 57.01 had significantly lower PSI-scores (Grade 3 or higher; 0/19 [0%] versus 16/41 [39%] versus 17/40 [42%]; p = < 0.001), GI-scores (Grade 2 or higher; 0/19 [0%] versus 19/41 [46%] versus 28/40 [70%]; p = < 0.001) and BOP-Scores (2/19 [1%] versus 38/41 [92%] versus 40/40 [100%]; p = < 0.001) in comparison to naive PLWHIV and PLWHIV receiving cART, who were both not carriers of HLA-B 57.01. A lower value of PSI-, GI- and BOP-Score is associated with improved periodontal health. The adjusted odds ratio (OR) of periodontitis was decreased in patients who were carriers of HLA-B 57.01 by measurement of PSI-Score (OR = 0.006, 95% confidence interval (CI) = 0.001 to 0.026), GI-Score (OR = 0.018, 95% confidence interval (CI) = 0.003 to 0.104) and BOP-Score (OR = 0.003, 95% confidence interval (CI) = < 0.001 to 0.011).

CONCLUSIONS

HLA-B 57.01 is an independent resistance indicator for generalized periodontitis in PLWHIV with respect to established cofactors.

Microbial colonization of the periodontal pocket and its significance for periodontal therapy

The aim of this paper was to evaluate strategies for periodontal therapy from the perspective of periodontal disease being a consequence of microbial colonization of the periodontal pocket environment. In classic bacterial infections the diversity of the microbiota decreases as the disease develops. In most cases of periodontitis, however, the diversity of the flora increases. Most incriminating bacteria are thought to harm tissues significantly only if present in high numbers over prolonged periods of time. Clinical trials have repeatedly demonstrated that scaling and root planing, a procedure that aims to remove subgingival bacterial deposits by scraping on the tooth surface within the periodontal pocket, is effective. At present, for the therapy of any form of periodontal disease, there exists no protocol with proven superiority, in terms of efficiency or effectiveness, over scaling and root planing plus systemic amoxicillin and metronidazole. Some exponents advocate rationing these drugs for patients with a specific microbial profile. However, the evidence for any benefit of bacteriology-assisted clinical protocols is unsatisfactory. Treated sites are subject to recolonization with a microbiota similar to that present before therapy. The degree and speed of recolonization depends on the treatment protocol, the distribution patterns of periodontal microorganisms elsewhere in the oral cavity and the quality of the patient's oral hygiene. To limit the use of antibiotics and to avoid accumulation of harmful effects by repeated therapy, further efforts must be made to optimize procedures addressing the microbial colonization and recolonization of the periodontal pocket.

Mechanisms of human cytomegalovirus infection with a focus on epidermal growth factor receptor interactions

Human cytomegalovirus (HCMV) is a widespread opportunistic herpesvirus that causes severe diseases in immunocompromised individuals. It has a high prevalence worldwide that is linked with socioeconomic factors. Similar to other herpesviruses, HCMV has the ability to establish lifelong persistence and latent infection following primary exposure. HCMV infects a broad range of cell types. This broad tropism suggests that it may use multiple receptors for host cell entry. The identification of receptors used by HCMV is essential for understanding viral pathogenesis, because these receptors mediate the early events necessary for infection. Many cell surface components have been identified as virus receptors, such as epidermal growth factor receptor (EGFR), which is characterized by tyrosine kinase activity and plays a crucial role in the control of key cellular transduction pathways. EGFR is essential for HCMV binding, signaling, and host cell entry. This review focuses on HCMV infection via EGFR on different cell types and its implications for the cellular environment, viral persistence, and infection.

Transcriptome analysis of bacteriophage communities in periodontal health and disease

BACKGROUND

The role of viruses as members of the human microbiome has gained broader attention with the discovery that human body surfaces are inhabited by sizeable viral communities. The majority of the viruses identified in these communities have been bacteriophages that predate upon cellular microbiota rather than the human host. Phages have the capacity to lyse their hosts or provide them with selective advantages through lysogenic conversion, which could help determine the structure of co-existing bacterial communities. Because conditions such as periodontitis are associated with altered bacterial biota, phage mediated perturbations of bacterial communities have been hypothesized to play a role in promoting periodontal disease. Oral phage communities also differ significantly between periodontal health and disease, but the gene expression of oral phage communities has not been previously examined.

RESULTS

Here, we provide the first report of gene expression profiles from the oral bacteriophage community using RNA sequencing, and find that oral phages are more highly expressed in subjects with relative periodontal health. While lysins were highly expressed, the high proportion of integrases expressed suggests that prophages may account for a considerable proportion of oral phage gene expression. Many of the transcriptome reads matched phages found in the oral cavities of the subjects studied, indicating that phages may account for a substantial proportion of oral gene expression. Reads homologous to siphoviruses that infect Firmicutes were amongst the most prevalent transcriptome reads identified in both periodontal health and disease. Some genes from the phage lytic module were significantly more highly expressed in subjects with periodontal disease, suggesting that periodontitis may favor the expression of some lytic phages.

CONCLUSIONS

As we explore the contributions of viruses to the human microbiome, the data presented here suggest varying expression of bacteriophage communities in oral health and disease.

The Biofilm Community-Rebels with a Cause

Oral Biofilms are one of the most complex and diverse ecosystem developed by successive colonization of more than 600 bacterial taxa. Development starts with the attachment of early colonizers such as Actinomyces species and oral streptococci on the acquired pellicle and tooth enamel. These bacteria not only adhere to tooth surface but also interact with each other and lay foundation for attachment of bridging colonizer such as Fusobacterium nucleatum followed by late colonizers including the red complex species: Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola-the founders of periodontal disease. As the biofilm progresses from supragingival sites to subgingival sites, the environment changes from aerobic to anaerobic thus favoring the growth of mainly Gram-negative obligate anaerobes while restricting the growth of the early Gram-positive facultative aerobes. Microbes present at supragingival level are mainly related to gingivitis and root-caries whereas subgingival species advance the destruction of teeth supporting tissues and thus causing periodontitis. This review summarizes our present understanding and recent developments on the characteristic features of supra- and subgingival biofilms, interaction between different genera and species of bacteria constituting these biofilms and draws our attention to the role of some of the recently discovered members of the oral community.

Toll-like receptor 9 gene polymorphism in chronic and aggressive periodontitis patients

AIM

Periodontitis is a multifactorial disease, with microbial dental plaque as the primary etiological factor. However, the manifestation and progression of periodontitis is influenced by a wide variety of other determinants and factors such as social and behavioral factors, systemic factors, microbial composition of dental plaque, genetic, and many other emerging risk factors. The aim of this study was to analyze genetic polymorphisms in the toll-like receptor 9 (TLR9) gene at - 1237C/T and its association with chronic and generalized aggressive periodontitis (GAgP) in an Indian population.

MATERIALS AND METHODS

This study was carried out on 90 subjects, which included 30 GAgP and 30 chronic periodontitis patients and 30 healthy controls. Within the limitations of our study, only 30 subjects were included in each group due to the low prevalence of GAgP patients. Blood samples were drawn from the subjects and analyzed for TLR9 genetic polymorphism at - 1237C/T by using polymerase chain reaction-restriction fragment length polymorphism method.

RESULTS

No significant difference was found in genotype and allele frequency of TLR9 genetic polymorphism (- 1237C/T) in generalized aggressive and chronic periodontitis patients and healthy controls.

CONCLUSION

Toll-like receptor 9 genetic polymorphism at - 1237C/T may not be associated with GAgP and chronic periodontitis patients in Indian population.

Human cytomegalovirus tropism for mucosal myeloid dendritic cells

Human CMV infections are a serious source of morbidity and mortality for immunocompromised patients and for the developing fetus. Because of this, the development of new strategies to prevent CMV acquisition and transmission is a top priority. Myeloid dendritic cells (DC) residing in the oral and nasal mucosae are among the first immune cells to encounter CMV during entry and greatly contribute to virus dissemination, reactivation from latency, and horizontal spread. Albeit affected by the immunoevasive tactics of CMV, mucosal DC remain potent inducers of cellular and humoral immune responses against this virus. Their natural functions could thus be exploited to generate long-lasting protective immunity against CMV by vaccination via the oronasal mucosae. Although related, epithelial Langerhans-type DC and dermal monocyte-derived DC interact with CMV in dramatically different ways. Whereas immature monocyte-derived DC are fully permissive to infection, for instance, immature Langerhans-type DC are completely resistant. Understanding these differences is essential to design innovative vaccines and new antiviral compounds to protect these cells from CMV infection in vivo.

Altered oral viral ecology in association with periodontal disease

The human oral cavity is home to a large and diverse community of viruses that have yet to be characterized in patients with periodontal disease. We recruited and sampled saliva and oral biofilm from a cohort of humans either periodontally healthy or with mild or significant periodontal disease to discern whether there are differences in viral communities that reflect their oral health status. We found communities of viruses inhabiting saliva and the subgingival and supragingival biofilms of each subject that were composed largely of bacteriophage. While there were homologous viruses common to different subjects and biogeographic sites, for most of the subjects, virome compositions were significantly associated with the oral sites from which they were derived. The largest distinctions between virome compositions were found when comparing the subgingival and supragingival biofilms to those of planktonic saliva. Differences in virome composition were significantly associated with oral health status for both subgingival and supragingival biofilm viruses but not for salivary viruses. Among the differences identified in virome compositions was a significant expansion of myoviruses in subgingival biofilm, suggesting that periodontal disease favors lytic phage. We also characterized the bacterial communities in each subject at each biogeographic site by using the V3 hypervariable segment of the 16S rRNA and did not identify distinctions between oral health and disease similar to those found in viral communities. The significantly altered ecology of viruses of oral biofilm in subjects with periodontal disease compared to that of relatively periodontally healthy ones suggests that viruses may serve as useful indicators of oral health status.

Little is known about the role or the constituents of viruses as members of the human microbiome. We investigated the composition of human oral viral communities in a group of relatively periodontally healthy subjects or significant periodontitis to determine whether health status may be associated with differences in viruses. We found that most of the viruses present were predators of bacteria. The viruses inhabiting dental plaque were significantly different on the basis of oral health status, while those present in saliva were not. Dental plaque viruses in periodontitis were predicted to be significantly more likely to kill their bacterial hosts than those found in healthy mouths. Because oral diseases such as periodontitis have been shown to have altered bacterial communities, we believe that viruses and their role as drivers of ecosystem diversity are important contributors to the human oral microbiome in health and disease states.

Detection of human cytomegalovirus and Epstein-Barr Virus in symptomatic and asymptomatic apical periodontitis lesions by real-time PCR

OBJECTIVES

Recent studies have investigated the occurrence of human cytomegalovirus and Epstein-Barr Virus in samples from apical periodontitis lesions and a role in the pathogenesis of this disease has been suggested. Because genotype distribution and seroprevalence of EBV and HCMV differ among populations, it is important to determine the presence of these viruses in endodontic periapical lesions of different populations. The aims of this study were to determine the presence of HCMV and EBV DNAs in samples from Turkish patients with symptomatic and asymptomatic apical periodontitis lesions using real-time polymerase chain reaction method and to evaluate their presence in both symptomatic and asymptomatic apical periodontitis lesions.

STUDY DESIGN

Periapical samples were collected from 12 asymptomatic and 16 symptomatic periapical lesions in conjunction with apicectomy. HCMV and EBV DNAs were identified in the samples by real-time PCR. The chi-squared test with Yates's correction or the Fisher's exact test was used to analyse the significance of differences.

RESULTS

HCMV DNA was detected in 10 of the 16 (62.5%) symptomatic and in five of the 12 (41.7 %) asymptomatic periapical study lesions. The EBV DNA was identified in seven of the 16 (43.7 %) symptomatic and three of the 12 (25 %) asymptomatic periapical lesions. The difference in occurrence of HCMV and EBV DNA between symptomatic and asymptomatic periapical lesions was not statistically significant. (All comparisons have p > 0.05).

CONCLUSION

Our findings suggest that HCMV and EBV is a frequent inhabitant of both symptomatic and asymptomatic apical periodontitis lesions of endodontic origin in Turkish population.

Investigação do vírus Epstein-Barr em pacientes com Periodontite Crônica

INTRODUÇÃO: Nos últimos anos, um número crescente de estudos sugere a participação dos herpesvírus na doença periodontal. OBJETIVO: Este trabalho investiga a relação entre a presença do herpesvírus Epstein-Barr (EBV) e a infecção periodontal em pacientes com periodontite crônica. METODOLOGIA: Foram coletadas amostras de biofilme subgengival de sítios com profundidades de sondagem de 4 a 6 mm e > 7 mm, de 28 pacientes com periodontite crônica. Como controles, foram incluídos 16 indivíduos, sistemicamente saudáveis e sem doença periodontal. Adicionalmente, parâmetros clínicos de profundidade de sondagem (PS), nível clínico de inserção (NCI) e índice de sangramento à sondagem (SS) foram registrados. RESULTADO: Os resultados demonstraram médias de 2,7 mm PS, 1,7 mm NCI e 0,3% dos sítios apresentaram SS. A investigação do EBV no biofilme subgengival dos grupos foi realizada por meio da reação em cadeia da polimerase com primer espécie-específico. Os resultados da análise viral indicaram ausência de EBV em todas as amostras subgengivais analisadas. CONCLUSÃO: A partir destes resultados, não foi encontrada relação entre a presença do herpesvírus Epstein-Barr e a periodontite crônica.

Relationship between herpesviruses and periodontopathogens in patients with HIV and periodontitis

BACKGROUND

The purpose of the present study is to verify a possible association between herpesviruses and periodontal pathogens in individuals with human immunodeficiency virus (HIV) and periodontitis.

METHODS

Twenty-seven patients with HIV and chronic periodontitis and 23 patients with HIV and gingivitis were included in the study. Probing depth, clinical attachment loss, gingival index, and plaque index were recorded. Blood, saliva, and subgingival plaque were processed for viral and bacterial identification. Bacteria were identified by 16S rRNA-based polymerase chain reaction and viruses by the nested polymerase chain reaction.

RESULTS

For the chronic periodontitis group, Epstein-Barr (EBV)-1 (70.4%) and Tannerella forsythia (Tf) (51.8%) presented higher detection in subgingival plaque and saliva (81.5% and 40.7%, respectively) than in blood (22% and 0%, respectively) (P <0.005 and P <0.0001, respectively). Porphyromonas gingivalis (Pg) was more frequent in subgingival plaque (77.7%; P <0.0001). In the gingivitis group, Pg and human cytomegalovirus (HCMV) presented higher frequency in subgingival plaque (95.6% and 91.3%, respectively; P <0.0001 and P = 0.004). Tf and EBV-1 were detected more frequently in subgingival plaque (47.8% and 78.3%, respectively) and saliva (52.2% and 52.2%, respectively; P = 0.004 and P <0.005) than in blood. EBV-1, EBV-1-HCMV, and presence of different viruses presented an association with periodontitis in saliva.

CONCLUSIONS

No association was detected for herpesviruses and periodontal pathogens in patients who are HIV-positive with periodontitis. EBV-1 and coinfection (EBV-1-HCMV) were associated with patients who are HIV-positive with periodontitis.

The innate immune system and diabetes mellitus: the relevance of periodontitis? A hypothesis

About a decade ago, a hypothesis was proposed suggesting that the innate immune system, including acute-phase reactants, contribute to the development of T2DM [Type 2 DM (diabetes mellitus)] and the metabolic syndrome. In this model, it was hypothesized that the innate immune system modulates the effects of many factors, including genes, fetal programming, nutrition and aging, upon the later development of metabolic problems associated with insulin resistance. In this present article, we expand this hypothesis by looking at the involvement of periodontitis in DM and its complications. Periodontitis is a common inflammatory process involving the innate immune system and is associated with DM. We will also illustrate how dental disease is important in patients with DM and could be implicated in various diabetic complications.

The role of viruses in oral disease

The focus has traditionally been on bacteria and fungi when discussing microbiological aspects of oral disease. Viruses are probably more involved in diseases associated with the oral cavity than has been previously thought. The role of several viruses in ulceration is well known, but viruses of the herpes family may play a role in periodontitis, and papillomaviruses are probably involved in oral cancer. This review offers a brief introduction to virology before discussing the role of the more relevant viruses in oral disease. As to clinical application, it is concluded that the anti-herpes medication may, in some cases, be relevant in treating periodontitis, while papillomavirus vaccine would be expected to decrease the prevalence of oral cancer.

Human cytomegalovirus and Epstein-Barr virus inhibit oral bacteria-induced macrophage activation and phagocytosis

INTRODUCTION

Periodontal disease is an inflammatory condition caused by periodontal microorganisms. Viruses such as human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV) are associated with certain types of periodontal disease, but their roles in promoting the disease are unclear. Because both viruses infect human macrophages, cells which play key roles in the clearance of pathogenic bacteria, it is likely that the viruses alter the functional capacity of macrophages by inhibiting their defense mechanisms against invading pathogens.

METHODS

Macrophages preinfected with HCMV or EBV were evaluated following stimulation by selected oral bacteria. Bacteria-induced macrophage activation was assayed by measuring the levels of tumor necrosis factor-alpha (TNF-alpha) produced in the media, and phagocytic activity was analysed by a phagocytosis assay with fluorescein isothiocyanate-labeled bacteria. The virus-infected macrophages were also subjected to semi-quantitative polymerase chain reaction to measure the expression of toll-like receptor 9, which is involved in the activation of phagocytosis-related pathways.

RESULTS

Both HCMV and EBV significantly diminished the TNF-alpha production typically induced by oral bacteria, inhibited the phagocytic activity of macrophages, and downregulated the expression of toll-like receptor 9.

CONCLUSION

Infection by HCMV or EBV inhibits the functional ability of macrophages to respond to bacterial challenge, thereby suggesting their pathogenic role in the development of periodontal disease.

Herpesviruses and periodontal disease: a cautionary tale

Periodontitis is an inflammatory disease of bacterial origin, characterized by an inconstant progression of lesions affecting the tooth supporting tissues. In spite of more than half a century of research efforts, the clinician still lacks any specific molecular or microbial diagnostic tool to predict the progression of periodontal lesions. Recently, several reports have proposed a role for some herpesviruses in the etiology of destructive phases of periodontitis. This paper critically analyzes these data in the light of consolidated knowledge that was developed in the characterization of virus-bacteria cooperative interactions, and proposes new topics of investigation to clarify the role of herpesviral infections in periodontitis and their potential predictive role as markers of progression.

Human cytomegalovirus and Epstein-Barr virus in apical and marginal periodontitis: a role in pathology?

Periodontitis is presumably caused by bacterial infection, but it has been shown recently that affected tissue often contains human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV). The present study was initiated to evaluate the role of these viruses in the pathogenesis of periodontitis. HCMV and EBV were quantified in 40 apical and 25 marginal periodontitis samples using real time PCR. In situ hybridization or immunohistochemistry was carried out on apical samples to detect viral presence within cells. A possible association with relevant bacteria was examined. Of the apical periodontitis samples, 50% contained EBV, while none contained HCMV. Of the marginal periodontitis samples, 40% were positive for EBV and 12% for HCMV. With one exception, however, the amount of virus was close to the detection limits. EBV was only detected in 1 out of 15 healthy periodontium samples. Immunohistochemistry and in situ hybridization were all negative. Significant associations were found between periodontal EBV and the presence of Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis. Although there was an obvious association of the virus with clinical samples, it seems unlikely that these viruses play a major role in the pathogenesis of periodontitis of the average patient. Their presence may reflect that the clinical samples contain more blood or saliva compared to controls, or an accumulation of lymphoid cells harboring virus in the inflamed tissue.

Herpesviral-bacterial synergy in the pathogenesis of human periodontitis

PURPOSE OF REVIEW

Periodontitis is an infectious disease, but the specific mechanisms by which tooth-supportive tissues are lost remain obscure. This article proposes an infectious disease model for periodontitis in which herpesviral-bacterial interactions assume a major etiopathogenic role.

RECENT FINDINGS

Epstein-Barr virus type 1, cytomegalovirus and other herpesviruses occur at a high frequency in aggressive periodontitis lesions. Also, herpesvirus-infected periodontitis lesions tend to harbor elevated levels of classic periodontopathic bacteria, including Porphyromonas gingivalis, Dialister pneumosintes, Prevotella intermedia, Prevotella nigrescens, Campylobacter rectus, Treponema denticola and Actinobacillus (Aggregatibacter) actinomycetemcomitans.

SUMMARY

Conceivably, a herpesvirus active infection in the periodontium impairs local defenses, thereby permitting overgrowth and increased aggressiveness of periodontopathic bacteria. In turn, periodontal pathogenic bacteria may augment the virulence of periodontal herpesviruses. It is suggested that interactions among herpesviruses and specific bacterial species constitute an important pathogenetic feature of periodontitis and maybe also of various non-oral infections.