Association between human herpes simplex virus and periodontitis: results from the continuous National Health and Nutrition Examination Survey 2009-2014

Role of viruses in periodontitis: An extensive review of herpesviruses, human immunodeficiency virus, coronavirus-19, papillomavirus and hepatitis viruses

Periodontitis is the inflammation of the supporting structures around the dentition. Several microbial agents, mostly bacteria, have been identified as causative factors for periodontal disease. On the other hand, oral cavity is a rich reservoir for viruses since it contains a wide variety of cell types that can be targeted by viruses. Traditionally, the focus of research about the oral flora has been on bacteria because the most widespread oral diseases, like periodontitis and dental caries, are outcomes of bacterial infection. However, recently and especially after the emergence of coronavirus disease 2019, there is a growing tendency toward including viruses also into the scope of oral microbiome investigations. The global high prevalence of periodontitis and viral infections may point out to a concomitant or synergistic effect between the two. Although the exact nature of the mechanism still is not clearly understood, this could be speculated through the manipulation of the immune system by viruses; hence facilitating the furthermore colonization of the oral tissues by bacteria. This review provides an extensive and detailed update on the role of the most common viruses including herpes family (herpes simplex, varicella-zoster, Epstein-Barr, cytomegalovirus), Human papillomaviruses, Human immunodeficiency virus and severe acute respiratory syndrome coronavirus 2 in the initiation, progression and prognosis of periodontitis.

Herpes simplex virus-induced upregulation of inflammatory cytokines in human gingival fibroblasts

Herpes simplex virus type 1 (HSV-1) is the leading pathogen in the maxillo-facial region, affecting millions of individuals worldwide. Its periodic reactivation aligns with the most common course pattern of periodontal disease. The present study used RNA sequencing to investigate the transcriptomes of human gingival fibroblasts (HGFs) following HSV-1 infection from the early to late stages (12-72 h). At the early stage of infection (12 h post-infection), the most upregulated genes were interferon (IFN) regulatory factor family members, toll-like receptor (TLR) family members, IFN-β1, interleukin (IL)-1, C-C motif ligands, chemokine (C-X-C motif) ligands (CXCLs), and tumor necrosis factor (TNF). The strongest differential expression was observed in TNF, nucleotide-binding oligomerization domain-like receptor (NLR), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathways. At the late stage of infection, the most upregulated genes were CXCLs and ILs. The differentially expressed genes were divided into nine clusters, according to the time series expression trend. Next, the prominent activation of TLRs, retinoic acid-inducible gene I-like receptor signaling, NLRs, and downstream IFNAR-JAK-STAT signaling pathways were observed via a modified HSV-1 infection map. The HSV-1-induced upregulation of inflammatory cytokines in HGFs may drive inflammatory processes in periodontitis. The dynamic variations in mRNAs in HGFs from the early to late stages after HSV-1 infection can provide an analytical framework for determining the host anti-viral defense response to antagonize HSV-1 infection in periodontal tissues.

Association between human herpes simplex virus and severe headache or migraine among aged 20-49 years: a cross-sectional study

Background and purpose

Previous studies have shown that human herpes simplex virus (HSV) infection may be associated with the onset of headache or migraine. We aimed to investigate the association between HSV infection and severe headache or migraine.

Materials and methods

The cross-sectional data on 5,730 participants aged 20-49 years were obtained from the 1999-2004 National Health and Nutrition Examination Survey (NHANES). We used weighted logistic regression analysis to assess the association between HSV infection (HSV-1 gG-1 and HSV-2 gG-2) and severe headache or migraine, and performed subgroup analyses.

Results

Our study found that women, higher education, higher body mass index, better family conditions, smoking and alcohol consumption were all associated with severe headaches or migraines. After adjusting for confounding factors such as sex, age, race, and education, HSV-2 (+) was still significantly associated with severe headache or migraine (OR = 1.22, 95%CI:1.03-1.46, p = 0.0443). In subgroup analyses, we found that participants with HSV-1 (-) and HSV-2 (+) were also significantly associated with severe headache or migraine (OR = 1.41, 95%CI:1.04-1.91, p = 0.0281).

Conclusion

HSV-2 gG-2(+) was significantly associated with severe headache or migraine.

Centrifugal Microfluidic Cell Culture Platform for Physiologically Relevant Virus Infection Studies: A Case Study with HSV-1 Infection of Periodontal Cells

Static well plates remain the gold standard to study viral infections in vitro, but they cannot accurately mimic dynamic viral infections as they occur in the human body. Therefore, we established a dynamic cell culture platform, based on centrifugal microfluidics, to study viral infections in perfusion. To do so, we used human primary periodontal dental ligament (PDL) cells and herpes simplex virus-1 (HSV-1) as a case study. By microscopy, we confirmed that the PDL cells efficiently attached and grew in the chip. Successful dynamic viral infection of perfused PDL cells was monitored using fluorescent imaging and RT-qPCR-based experiments. Remarkably, viral infection in flow resulted in a gradient of HSV-1-infected cells gradually decreasing from the cell culture chamber entrance towards its end. The perfusion of acyclovir in the chip prevented HSV-1 spreading, demonstrating the usefulness of such a platform for monitoring the effects of antiviral drugs. In addition, the innate antiviral response of PDL cells, measured by interferon gene expression, increased significantly over time in conventional static conditions compared to the perfusion model. These results provide evidence suggesting that dynamic viral infections differ from conventional static infections, which highlights the need for more physiologically relevant in vitro models to study viral infections.

Herpes Simplex Virus Type 1 Infection of Human Periodontal Ligament

The periodontal ligament (PDL) is a complex connective tissue that connects the tooth root to the dental alveolar bone and plays crucial mechanical roles. PDL also exhibits regenerative roles and regulatory functions to maintain periodontium integrity and homeostasis. While PDL exposure to oral microbial pathogens is common, virtually nothing is known regarding viral infections of PDL. In particular, human herpes simplex virus type 1 (HSV-1) persistently infects the oral cavity through infections of the oral epithelium, connective tissue and neurons. While the oral spread of HSV-1 is generally asymptomatic, this virus has also been implicated in various oral pathologies. In this study, using a primary cell model derived from PDL (PDL cells), and whole surgical fragments of PDL, we provide evidence supporting the efficient infection of PDL by HSV-1 and the promotion of cytopathic effects. Infection of PDL by HSV-1 was also associated with an acute innate inflammatory response, as illustrated by the production of antiviral interferons and pro-inflammatory cytokines. Furthermore, this inflammatory response to HSV-1 was exacerbated in the presence of bacterial-derived products, such as peptidoglycans. This work therefore highlights the ability of HSV-1 to infect mesenchymal cells from PDL, suggesting that PDL may serve as a viral reservoir for the periodontal spread of HSV-1. Moreover, this raises questions about HSV-1 oral pathogenesis, as HSV-1-associated cytopathic and inflammatory effects may contribute to profound alterations of PDL integrity and functioning.

Association between virus infection and periodontitis: Evidence from the National Health and Nutrition Examination Survey 2009-2014

Periodontitis is a cumulative inflammatory disease associated with multiple health conditions and various systemic diseases. As a common disease, virus infection along with its consequences has become a serious health burden. The study aims to evaluate the relationship between common viruses including hepatitis virus, human immunodeficiency virus (HIV), herpes simplex virus (HSV), human papillomavirus (HPV), and periodontitis. The data from the US National Health and Nutrition Examination Survey (NHANES) 2009-2014 was adopted and screened through, including 10 714 participants. Generalized linear regression was conducted to verify the relationships between the virus infections and periodontitis. Moreover, we also performed analyses in age and gender subgroups. The results suggested that the infection of HCV, HSV-1, and HSV-2 was significantly associated with the prevalence of periodontitis (odds ratio [OR] 1.46, 95% confidence interval [CI] 1.26-1.70; OR 1.09, 95% CI 1.05-1.13; OR 1.06, 95% CI 1.01 - 1.11, respectively) and risk of developing moderate or severe periodontitis (OR 1.51, 95% CI 1.29-1.77; OR 1.08, 95% CI 1.04-1.12; OR 1.05, 95% CI 1.01-1.10, respectively) after adjusting all relevant co-factors. Subgroup analyses revealed a steady association between periodontitis and hepatitis C virus (HCV) or HSV-1 infection, while the relationship between HSV-2 and HPV infection can also be found in some subgroups. The presence of HCV and HSV infection was found to be significantly associated with the prevalence of periodontitis, including moderate or severe cases. Moreover, the association of periodontitis and HPV infection can also be observed in people < 35 years.

Antiviral activity of temporin-1CEb analogues against gingival infection with herpes simplex virus type 1

Introduction

Oral herpes infections caused by herpes simplex virus type 1 (HSV-1) are one of the most common in the human population. Recently, they have been classified as an increasing problem in immunocompromised patients and those suffering from chronic inflammation of the oral mucosa and gums. Treatment mainly involves nucleoside analogues, such as acyclovir and its derivatives, which reduce virus replication and shedding. As drug-resistant strains of herpes emerge rapidly, there is a need for the development of novel anti-herpes agents. The aim of the study was to design an antiviral peptide, based on natural compounds, non-toxic to the host, and efficient against drug-resistant HSV-1. Here, we designed a lysine-rich derivative of amphibian temporin-1CEb conjugated to peptides penetrating the host cell membrane and examined their activity against HSV-1 infection of oral mucosa.

Methods

We assessed the antiviral efficiency of the tested compound in simple 2D cell models (VeroE6 and TIGKs cells) and a 3D organotypic model of human gingiva (OTG) using titration assay, qPCR, and confocal imaging. To identify the molecular mechanism of antiviral activity, we applied the Azure A metachromatic test, and attachment assays techniques. Toxicity of the conjugates was examined using XTT and LDH assays.

Results

Our results showed that temporin-1CEb analogues significantly reduce viral replication in oral mucosa. The mechanism of peptide analogues is based on the interaction with heparan sulfate, leading to the reduce attachment of HSV-1 to the cell membrane. Moreover, temporin-1CEb conjugates effectively penetrate the gingival tissue being effective against acyclovir-resistant strains. Collectively, we showed that temporin-1CEb can be regarded as a novel, naturally derived antiviral compound for HSV-1 treatment.

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.

Organotypic model of the gingiva for studying bacterial and viral pathogens implicated in periodontitis

Background

Three-dimensional (3D) tissue models bridge the gap between conventional two-dimensional cell cultures and animal models. The aim of this study was to develop an organotypic 3D gingival (OTG) model to provide a tool to investigate bacterial and viral pathogens in periodontitis.

Methods

The OTG model composed of gingival fibroblasts (GFs) and telomerase-immortalized gingival keratinocytes (TIGKs) was constructed and applied to study infections by Porphyromonas gingivalis and herpes simplex virus 1 (HSV-1). Immunohistochemical staining, confocal microscopy, qPCR, titration techniques, and colony-forming unit counts were applied to interrogate epithelial markers expression, monitor P. gingivalis and HSV-1 presence, and evaluate the immune response along with the efficiency of antimicrobial drugs.

Results

The OTG model resembled the morphology of the human gingiva. During infection, both pathogens penetrated deep into the tissue and persisted for a few days with P. gingivalis also forming a biofilm on the cell surface. The infection triggered the expression of inflammatory mediators in cells and both pathogens were efficiently eliminated by specific antimicrobials.

Conclusions

Presented OTG model constitutes a simple and convenient tool to study the interaction between bacterial and viral pathogens within the gingival tissue, including penetration, persistence and biofilm formation. It is also suitable to examine the efficiency of antimicrobial drugs.