HHV-6, HHV-7, HHV-8 in gingival biopsies from chronic adult periodontitis patients. A case-control study

Associations between Oral Human Herpesvirus-6 and -7 and Periodontal Conditions in Older Adults

BACKGROUND

The associations between oral human herpesvirus-6 (HHV-6) and HHV-7, periodontal conditions, and lifestyle-related diseases, such as hypertension, diabetes, and dyslipidemia, have not been fully investigated in older adults.

METHODS

Seventy-four older patients who visited Hiroshima University Hospital were enrolled. Tongue swab samples were employed, and a real-time polymerase chain reaction was performed to detect HHV-6 and HHV-7 DNA. Dental plaque accumulation, probing pocket depth, and bleeding on probing (BOP) (i.e., a sign of periodontal inflammation) were examined. The periodontal inflamed surface area (PISA) value (i.e., an indicator of the severity of periodontitis) was also examined.

RESULTS

Of the 74 participants, one participant (1.4%) was HHV-6 DNA-positive and 36 participants (48.6%) were HHV-7 DNA-positive. A significant association between HHV-7 DNA and probing depth was found (p = 0.04). The HHV-7 DNA-positive participants had a higher positive rate of a ≥6-mm periodontal pocket with BOP (25.0%) than the HHV-7 DNA-negative participants (7.9%). Additionally, the HHV-7 DNA-positive participants had a higher PISA value than the HHV-7 DNA-negative participants. However, there was no significant association between HHV-7 and the PISA value (p = 0.82). No significant association was found between HHV-7 and lifestyle-related diseases (p > 0.05).

CONCLUSIONS

Oral HHV-7 infection is associated with a deep periodontal pocket.

Impact of different types of herpesviral infections in the oral cavity

The herpesviruses are ubiquitous, doubled-stranded DNA viruses that can reactivate under conditions such as immunosuppressive therapy, acquired immunodeficiency syndrome, malnutrition, and immunosenescence. There are eight types of herpesviruses: Human herpesvirus simplex (HSV) type I (HSV-1) and HSV type II (HSV-2), varicella-zoster virus (VZV), epstein-Barr virus (EBV), cytomegalovirus, human herpesvirus (HHV)-6, HHV-7, and HHV-8 or Kaposi’s sarcoma herpesvirus. Some of these viruses can infect the oral cavity, leading to different types of lesions. Specifically, labial herpes (HSV-1 and less frequently HSV-2), zoster (VZV), infectious mononucleosis and oral hairy leukoplakia (EBV), and Kaposi’s Sarcoma (HHV-8) are the most common viruses infecting the oral cavity. Some of these viruses can act in synergy with other herpesviruses or as distinct infectious agents. Other herpesviruses may have indirect effects in periodontal disease. The diagnosis is frequently based on signs and symptoms and depends on the experience of the examiner. Cytopathologic and/or histopathologic examination as well as immunological methods such as ELISA could help to elucidate cases. In addition, molecular techniques which can be sensitive and specific have been reported in the literature. These methods require low amounts of sample and could offer results faster than other traditional methods.

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.

Lipoteichoic acid (LTA) and lipopolysaccharides (LPS) from periodontal pathogenic bacteria facilitate oncogenic herpesvirus infection within primary oral cells

Kaposi's sarcoma (KS) remains the most common tumor arising in patients with HIV/AIDS, and involvement of the oral cavity represents one of the most common clinical manifestations of this tumor. HIV infection incurs an increased risk for periodontal diseases and oral carriage of a variety of bacteria. Whether interactions involving pathogenic bacteria and oncogenic viruses in the local environment facilitate replication or maintenance of these viruses in the oral cavity remains unknown. In the current study, our data indicate that pretreatment of primary human oral fibroblasts with two prototypical pathogen-associated molecular patterns (PAMPs) produced by oral pathogenic bacteria-lipoteichoic acid (LTA) and lipopolysaccharide (LPS), increase KSHV entry and subsequent viral latent gene expression during de novo infection. Further experiments demonstrate that the underlying mechanisms induced by LTA and/or LPS include upregulation of cellular receptor, increasing production of reactive oxygen species (ROS), and activating intracellular signaling pathways such as MAPK and NF-κB, and all of which are closely associated with KSHV entry or gene expression within oral cells. Based on these findings, we hope to provide the framework of developing novel targeted approaches for treatment and prevention of oral KSHV infection and KS development in high-risk HIV-positive patients.

Lessons learned and unlearned in periodontal microbiology

Periodontal diseases are initiated by bacterial species living in polymicrobial biofilms at or below the gingival margin and progress largely as a result of the inflammation elicited by specific subgingival species. In the past few decades, efforts to understand the periodontal microbiota have led to an exponential increase in information about biofilms associated with periodontal health and disease. In fact, the oral microbiota is one of the best-characterized microbiomes that colonize the human body. Despite this increased knowledge, one has to ask if our fundamental concepts of the etiology and pathogenesis of periodontal diseases have really changed. In this article we will review how our comprehension of the structure and function of the subgingival microbiota has evolved over the years in search of lessons learned and unlearned in periodontal microbiology. More specifically, this review focuses on: (i) how the data obtained through molecular techniques have impacted our knowledge of the etiology of periodontal infections; (ii) the potential role of viruses in the etiopathogenesis of periodontal diseases; (iii) how concepts of microbial ecology have expanded our understanding of host-microbe interactions that might lead to periodontal diseases; (iv) the role of inflammation in the pathogenesis of periodontal diseases; and (v) the impact of these evolving concepts on therapeutic and preventive strategies to periodontal infections. We will conclude by reviewing how novel systems-biology approaches promise to unravel new details of the pathogenesis of periodontal diseases and hopefully lead to a better understanding of their mechanisms.

Short-chain fatty acids from periodontal pathogens suppress histone deacetylases, EZH2, and SUV39H1 to promote Kaposi's sarcoma-associated herpesvirus replication

Periodontal pathogens such as Porphyromonas gingivalis and Fusobacterium nucleatum produce five different short-chain fatty acids (SCFAs) as metabolic by-products. We detect significantly higher levels of SCFAs in the saliva of patients with severe periodontal disease. The different SCFAs stimulate lytic gene expression of Kaposi's sarcoma-associated herpesvirus (KSHV) dose dependently and synergistically. SCFAs inhibit class-1/2 histone deacetylases (HDACs) and downregulate expression of silent information regulator-1 (SIRT1). SCFAs also downregulate expression of enhancer of zeste homolog2 (EZH2) and suppressor of variegation 3-9 homolog1 (SUV39H1), which are two histone N-lysine methyltransferases (HLMTs). By suppressing the different components of host epigenetic regulatory machinery, SCFAs increase histone acetylation and decrease repressive histone trimethylations to transactivate the viral chromatin. These new findings provide mechanistic support that SCFAs from periodontal pathogens stimulate KSHV replication and infection in the oral cavity and are potential risk factors for development of oral Kaposi's sarcoma (KS).

IMPORTANCE

About 20% of KS patients develop KS lesions first in the oral cavity, while other patients never develop oral KS. It is not known if the oral microenvironment plays a role in oral KS tumor development. In this work, we demonstrate that a group of metabolic by-products, namely, short-chain fatty acids, from bacteria that cause periodontal disease promote lytic replication of KSHV, the etiological agent associated with KS. These new findings provide mechanistic support that periodontal pathogens create a unique microenvironment in the oral cavity that contributes to KSHV replication and development of oral KS.

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.

Correlation of cytomegalovirus and human herpesvirus 7 with CD3+ and CD3+ CD4+ cells in chronic periodontitis patients

BACKGROUND AND OBJECTIVE

Human chronic periodontitis is an inflammatory process characterized by dense accumulation of immune cells in the periodontal tissue. The periodontitis can lead to loss of teeth in the patient and the pathogenesis of this disease is not completely known. This study tested the hypothesis that chronic periodontitis-affected sites can harbor betaherpesviruses and that viruses are linked to a profile of the inflammatory infiltrate.

MATERIAL AND METHODS

Biopsies of periodontal tissue were taken from periodontitis-affected patients and from healthy subjects. Immunohistochemistry was performed to count CD19(+) B cells, CD3(+) total T cells, T-CD4(+) and T-CD8(+) cell subsets, and PCR was performed to detect cytomegalovirus and human herpesvirus 6 and 7 in the samples. One slide of each sample was stained with Giemsa for histopathological examination and to evaluate the quality of the cellular infiltrate.

RESULTS

As expected, tissues collected from healthy subjects presented no significant level of inflammatory infiltration and were therefore excluded from immunostaining procedures. Results showed that CD19(+) B cells were in higher number than CD3(+) T cells in the periodontitis-affected tissue, but this was not statistically significant. The T-CD4(+) lymphocyte subset was significantly higher than the T-CD8(+) lymphocyte subset (p = 0.004) in the samples. Cytomegalovirus and human herpesvirus 7 were found at periodontitis-affected sites, but not in tissue collected from healthy subjects (p = 0.04 and p = 0.04, respectively). Human herpesvirus 6 was rarely detected. We found a correlation between cytomegalovirus and lower CD19(+) /CD3(+) ratios (ratio < 0.9, p = 0.003) and between human herpesvirus 7 and lower CD19(+) /CD3(+) ratios (ratio < 0.9, p = 0.003) and higher CD4(+) /CD8(+) ratios (ratio > 1.1, p = 0.002).

CONCLUSION

This study shows that cytomegalovirus and human herpesvirus 7 can be present at periodontitis-affected sites but are uncommon at healthy periodontal sites. Moreover, our data suggest that cytomegalovirus can be related to an inflammatory infiltrate with predominance of CD3(+) T cells, whereas human herpesvirus 7 can be associated with an infiltrate with predominance of T-CD4(+) cells. However, further studies are necessary to support this hypothesis. Herpesviruses could play a role in human chronic periodontitis by modulation of the T cell response.

Human papillomavirus-16 prevalence in gingival tissue and its association with periodontal destruction: a case-control study

BACKGROUND

Human papillomavirus (HPV)-16 is detected in normal oral mucosa and several oral lesions, including squamous cell carcinoma, condyloma acuminatum, verruca vulgaris, focal epithelial hyperplasia, and periodontal diseases. It was hypothesized that HPV may be involved in periodontal breakdown and that periodontal tissue acts as a reservoir for the virus. Therefore, in this study, the prevalence of HPV-16 in the gingival tissue of Brazilians with periodontal health or disease is investigated.

METHODS

Fifty-six gingival samples from subjects with chronic periodontitis, 26 samples from subjects with gingivitis, and 22 samples from subjects with healthy peridontium were analyzed. Total DNA was extracted, and the presence of HPV-16 was assessed using a real-time polymerase chain reaction. Positive and negative controls were included in the reactions.

RESULTS

HPV-16 was not detected in any of the 104 gingival samples evaluated; therefore, this virus showed no association with periodontal disease in this study.

CONCLUSION

In the population studied, HPV-16 may not have participated in the pathogenesis of chronic periodontitis, and the gingival tissue did not act as a reservoir for this virus.

Human herpesvirus 7, Epstein-Barr virus and human cytomegalovirus in periodontal tissues of periodontally diseased and healthy subjects

AIMS

To evaluate (i) the presence of human herpesvirus 7 (HHV-7), Epstein-Barr virus (EBV) and human cytomegalovirus (HCMV), and (ii) the transcription pattern of HHV-7 in gingival biopsies from patients affected by periodontitis (P) and periodontally healthy subjects (H).

MATERIAL AND METHODS

Thirty-seven subjects (P: n=24; H: n=13) were included. Each P patient contributed two gingival biopsies (representative of a clinically affected and non-affected site) and each H subject contributed one gingival biopsy. After DNA extraction, nested polymerase chain reaction was used to identify the viruses.

RESULTS

HHV-7 was detected in 91.7% of P patients and in 61.5% of H subjects (p=0.02), EBV in 50.0% samples of P patients and 7.7% of H subjects (p=0.005) and HCMV only in one sample from H group. EBV was more frequently detected in biopsies from affected sites (50.0%) than from non-affected sites (16.7%) (p=0.008). HHV-7 transcription was detected in 15.4% of affected and 15.4% of non-affected sites.

CONCLUSIONS

The results indicate that (i) gingival tissues can be considered a potential reservoir for HHV-7; (ii) when present, HHV-7 persists in a latent state in the majority of cases; (iii) the presence of EBV seems to be associated with the diseased state of the patient and site.

Detection of human herpesvirus 6 in patients with oral chronic graft-vs-host disease following allogeneic progenitor cell transplantation

INTRODUCTION

Chronic graft-vs-host disease (cGVHD) is a major cause of morbidity in long-term survivors of allogeneic hematopoietic progenitor cell transplantation. Herpesviruses are involved in the occurrence and progression of various oral diseases.

AIM

The aim of this study was to investigate the role of human herpesvirus 6 (HHV6) in patients with oral manifestations of cGVHD.

MATERIALS AND METHODS

Peripheral blood and oral fluids (whole saliva, gingival crevicular fluid and parotid gland saliva) from 19 cGVHD patients, and 28 blood donors were examined for HHV6. Oral tissue samples were collected from 12 cGVHD patients and 12 healthy individuals. Nested polymerase chain reaction was employed to identify the HHV6.

RESULTS AND CONCLUSION

The virus was detected in whole saliva in 13 cGVHD patients (68%) and in 19 blood donors (67%). HHV6 was not identified in any of the gingival crevicular fluid and parotid gland saliva samples in cGVHD patients. In the control group 14.3% of both, four gingival crevicular fluid and four parotid gland saliva samples were positive. Two oral tissue samples of cGVHD patients were positive for HHV6. These results indicate that patients with oral manifestations of cGVHD and healthy individuals present high and similar incidence of HHV6 in blood and oral fluids. These data do not support the importance of HHV6 in oral lesions of cGVHD.

Kaposi's sarcoma-associated herpesvirus: clinical, diagnostic, and epidemiological aspects

Kaposi's sarcoma-associated herpesvirus (KSHI) is one of the few viruses proven to be associated with tumorigenesis in humans. Its causal association with all clinical and epidemiological variants of Kaposi's sarcoma (KS) is well established. KSHV is also involved in the pathogenesis of primary effusion lymphoma (PEL) and a subset of multicentric Castleman's disease (MCD). Possible associations of KSHV with other clinical settings have been extensively examined. The findings from several of these studies are contradictory and are yet to be resolved. Concentrated effort over the last decade, since the initial discovery of KSHV, led to the development of several experimental systems that resulted in a better comprehension of the biological characteristics of KSHV and set the stage for the understanding of mechainisms by which diseases are induced by the virus. The development of molecular, histological, and serological tools for KSHV diagnosis allowed researchers to track the transmission and to study the epidemiology of KSHV. These assays have been applied, in particular in ambiguous cases, in order to confirm clinically and pathologically based diagnoses. Here, we review the advances in the clinical, experimental, diagnostic, and epidemiological research of KSHV.