Human immunodeficiency virus infection of fibroblasts of dental pulp in seropositive patients

Ancient dental pulp: Masterpiece tissue for paleomicrobiology

Introduction

Dental pulp with special structure has become a good reference sample in paleomicrobiology‐related blood‐borne diseases, many pathogens were detected by different methods based on the diagnosis of nucleic acids and proteins.

Objectives

This review aims to propose the preparation process from ancient teeth collection to organic molecule extraction of dental pulp and summary, analyze the methods that have been applied to detect septicemic pathogens through ancient dental pulps during the past 20 years following the first detection of an ancient microbe.

Methods

The papers used in this review with two main objectives were obtained from PubMed and Google scholar with combining keywords: “ancient,” “dental pulp,” “teeth,” “anatomy,” “structure,” “collection,” “preservation,” “selection,” “photography,” “radiography,” “contamination,” “decontamination,” “DNA,” “protein,” “extraction,” “bone,” “paleomicrobiology,” “bacteria,” “virus,” “pathogen,” “molecular biology,” “proteomics,” “PCR,” “MALDI‐TOF,” “LC/MS,” “ELISA,” “immunology,” “immunochromatography,” “genome,” “microbiome,” “metagenomics.”

Results

The analysis of ancient dental pulp should have a careful preparation process with many different steps to give highly accurate results, each step complies with the rules in archaeology and paleomicrobiology. After the collection of organic molecules from dental pulp, they were investigated for pathogen identification based on the analysis of DNA and protein. Actually, DNA approach takes a principal role in diagnosis while the protein approach is more and more used. A total of seven techniques was used and ten bacteria (Yersinia pestis, Bartonella quintana, Salmonella enterica serovar Typhi, Salmonella enterica serovar Paratyphi C, Mycobacterium leprae, Mycobacterium tuberculosis, Rickettsia prowazeki, Staphylococcus aureus, Borrelia recurrentis, Bartonella henselae) and one virus (Anelloviridae) were identified. Y. pestis had the most published in quantity and all methods were investigated for this pathogen, S. aureus and B. recurrentis were identified by three different methods and others only by one. The combining methods interestingly increase the positive rate with ELISA, PCR and iPCR in Yersinia pestis diagnosis. Twenty‐seven ancient genomes of Y. pestis and one ancient genome of B. recurrentis were reconstructed. Comparing to the ancient bone, ancient teeth showed more advantage in septicemic diagnosis. Beside pathogen identification, ancient pulp help to distinguish species.

Conclusions

Dental pulp with specific tissue is a suitable sample for detection of the blood infection in the past through DNA and protein identification with the correct preparation process, furthermore, it helps to more understand the pathogens of historic diseases and epidemics.

Infectious Agents As Markers of Human Migration toward the Amazon Region of Brazil

Infectious agents are common companions of humans and since ancient times they follow human migration on their search for a better place to live. The study of paleomicrobiology was significantly improved in its accuracy of measurement with the constant development of better methods to detect and analyze nucleic acids. Human tissues are constantly used to trace ancient infections and the association of anthropological evidences are important to confirm the microbiological information. Infectious agents which establish human persistent infections are particularly useful to trace human migrations. In the present article, the evidence of infection by viral agents such as human T-lymphotropic virus 1, human T-lymphotropic virus 2, human herpes virus-8, JC virus, and a bacterium, Chlamydia trachomatis, was described using different methodologies for their detection. Their presence was further used as biomarkers associated with anthropological and other relevant information to trace human migration into the Amazon region of Brazil. The approach also evidenced their microbiological origin, emergence, evolution, and spreading. The information obtained confirms much of the archeological information available tracing ancient and more recent human migration into this particular geographical region. In this article, the paleomicrobiological information on the subject was summarized and reviewed.

Viral MicroRNAs Identified in Human Dental Pulp

INTRODUCTION

MicroRNAs (miRs) are a family of noncoding RNAs that regulate gene expression. They are ubiquitous among multicellular eukaryotes and are also encoded by some viruses. Upon infection, viral miRs (vmiRs) can potentially target gene expression in the host and alter the immune response. Although prior studies have reported viral infections in human pulp, the role of vmiRs in pulpal disease is yet to be explored. The purpose of this study was to examine the expression of vmiRs in normal and diseased pulps and to identify potential target genes.

METHODS

Total RNA was extracted and quantified from normal and inflamed human pulps (N = 28). Expression profiles of vmiRs were then interrogated using miRNA microarrays (V3) and the miRNA Complete Labeling and Hyb Kit (Agilent Technologies, Santa Clara, CA). To identify vmiRs that were differentially expressed, we applied a permutation test.

RESULTS

Of the 12 vmiRs detected in the pulp, 4 vmiRs (including those from herpesvirus and human cytomegalovirus) were differentially expressed in inflamed pulp compared with normal pulp (P < .05). Using bioinformatics, we identified potential target genes for the differentially expressed vmiRs. They included key mediators involved in the detection of microbial ligands, chemotaxis, proteolysis, cytokines, and signal transduction molecules.

CONCLUSIONS

These data suggest that miRs may play a role in interspecies regulation of pulpal health and disease. Further research is needed to elucidate the mechanisms by which vmiRs can potentially modulate the host response in pulpal disease.

Detection of HCV Persistent Infections in the Dental Pulp: A Novel Approach for the Detection of Past and Ancient Infections

The dental pulp is a sterile highly vascularized tissue and has been commonly used as a biological material to detect the genome of infectious agents that reach the dental tissue. Indeed, the pulp is also used to reveal past and ancient infections in the field of paleomicrobiology. The present study aimed to detect the presence of Hepatitis C virus (HCV) in a small community (approximately 400 inhabitants) in the Amazon region of Brazil (Nossa Senhora do Perpetuo Socorro, Vizeu, Para, Brazil) and standardize a technique for the detection of the virus in the dental pulp. Serum samples were collected from 48 patients whose teeth were clinically recommended for surgical extraction. The group comprised an equal number of males and females, mostly agriculture workers and housewives, respectively. The majority (64.6%) received less than one minimum wage and were ill educated (less than four years of school years). An enzyme immune assay was used to detect antibodies to HCV and the 9 (18.8%) positive samples were submitted to nucleic acid extraction in the blood (using the EXTRAzol) and the pulp (QIAamp DNA Micro Kit e kit RNeasy Plus Micro). The pulp was removed using a modified protocol without the use of liquid nitrogen. Nucleic acid was found in 8 of the dental pulp, but in 7 of the blood samples. Sequencing of one of the samples showed the presence of genotype 1.

CONCLUSIONS

A novel simplified methodology for the extraction and amplification of HCV nucleic acid was successful to detect the presence of persistent infections of the virus within the dental pulp tissue. The protocol may be helpful to detect past and ancient infections and to better understand the natural history of HCV.

Endodontic microbiology

Root canal therapy has been practiced ever since 1928 and the success rate has tremendously increased over the years owing to various advancements in the field. One main reason is the complete understanding of the microbiology involved in the endodontic pathology. This has helped us to modify the conventional treatment plans and effectively combat the microorganisms. Now, studies are aiming to explore the characteristics of the "most" resistant organism and the methods to eliminate them. This article gives an insight of the microbiology involved in endodontic pathology and discusses its role in our treatment procedure. Information from original reviews listed in PubMed, published from 1995 to 2010, has been mainly included in this review.

Different Roles of Odontoblasts and Fibroblasts in Immunity

Odontoblasts and fibroblasts are suspected to influence the innate immune response triggered in the dental pulp by micro-organisms that progressively invade the human tooth during the caries process. To determine whether they differ in their responses to oral pathogens, we performed a systematic comparative analysis of odontoblast-like cell and pulp fibroblast responses to TLR2-, TLR3-, and TLR4-specific agonists (lipoteichoic acid [LTA], double-stranded RNA, and lipopolysaccharide [LPS], respectively). Cells responded to these agonists by differential up-regulation of chemokine gene expression. CXCL2 and CXCL10 were thus increased by LTA only in odontoblast-like cells, while LPS increased CCL7, CCL26, and CXCL11 only in fibroblasts. Supernatants of stimulated cultures increased migration of immature dendritic cells compared with controls, odontoblast-like cells being more potent attractants than fibroblasts. Analysis of these data suggests that odontoblasts and pulp fibroblasts differ in their innate immune responses to oral micro-organisms that invade the pulp tissue.

A new method to extract dental pulp DNA: application to universal detection of bacteria

Background

Dental pulp is used for PCR-based detection of DNA derived from host and bacteremic microorganims. Current protocols require odontology expertise for proper recovery of the dental pulp. Dental pulp specimen exposed to laboratory environment yields contaminants detected using universal 16S rDNA-based detection of bacteria.

Methodology/Principal Findings

We developed a new protocol by encasing decontaminated tooth into sterile resin, extracting DNA into the dental pulp chamber itself and decontaminating PCR reagents by filtration and double restriction enzyme digestion. Application to 16S rDNA-based detection of bacteria in 144 teeth collected in 86 healthy people yielded a unique sequence in only 14 teeth (9.7%) from 12 individuals (14%). Each individual yielded a unique 16S rDNA sequence in 1–2 teeth per individual. Negative controls remained negative. Bacterial identifications were all confirmed by amplification and sequencing of specific rpoB sequence.

Conclusions/Significance

The new protocol prevented laboratory contamination of the dental pulp. It allowed the detection of bacteria responsible for dental pulp colonization from blood and periodontal tissue. Only 10% such samples contained 16S rDNA. It provides a new tool for the retrospective diagnostic of bacteremia by allowing the universal detection of bacterial DNA in animal and human, contemporary or ancient tooth. It could be further applied to identification of host DNA in forensic medicine and anthropology.

DNA examination of ancient dental pulp incriminates typhoid fever as a probable cause of the Plague of Athens

BACKGROUND

Until now, in the absence of direct microbiological evidence, the cause of the Plague of Athens has remained a matter of debate among scientists who have relied exclusively on Thucydides' narrations to introduce several possible diagnoses. A mass burial pit, unearthed in the Kerameikos ancient cemetery of Athens and dated back to the time of the plague outbreak (around 430 BC), has provided the required skeletal material for the investigation of ancient microbial DNA.

OBJECTIVE

To determine the probable cause of the Plague of Athens.

METHOD

Dental pulp was our material of choice, since it has been proved to be an ideal DNA source of ancient septicemic microorganisms through its good vascularization, durability and natural sterility.

RESULTS

Six DNA amplifications targeted at genomic parts of the agents of plague (Yersinia pestis), typhus (Rickettsia prowazekii), anthrax (Bacillus anthracis), tuberculosis (Mycobacterium tuberculosis), cowpox (cowpox virus) and cat-scratch disease (Bartonella henselae) failed to yield any product in 'suicide' reactions of DNA samples isolated from three ancient teeth. On the seventh such attempt, DNA sequences of Salmonella enterica serovar Typhi were identified providing clear evidence for the presence of that microorganism in the dental pulp of teeth recovered from the Kerameikos mass grave.

CONCLUSION

The results of this study clearly implicate typhoid fever as a probable cause of the Plague of Athens.

Palaeomicrobiology: current issues and perspectives

Palaeomicrobiology is an emerging field that is devoted to the detection, identification and characterization of microorganisms in ancient remains. Data indicate that host-associated microbial DNA can survive for almost 20,000 years, and environmental bacterial DNA preserved in permafrost samples has been dated to 400,000-600,000 years. In addition to frozen and mummified soft tissues, bone and dental pulp can also be used to search for microbial pathogens. Various techniques, including microscopy and immunodetection, can be used in palaeomicrobiology, but most data have been obtained using PCR-based molecular techniques. Infections caused by bacteria, viruses and parasites have all been diagnosed using palaeomicrobiological techniques. Additionally, molecular typing of ancient pathogens could help to reconstruct the epidemiology of past epidemics and could feed into current models of emerging infections, therefore contributing to the development of appropriate preventative measures.

Molecular detection of Bartonella spp. in the dental pulp of stray cats buried for a year

Bartonella henselae causes chronic bacteremia in cats. To test if B. henselae DNA can be recovered from the dental pulp of cats buried a year previously, we used PCR with primers for a sequence of the conserved groEL to test 104 teeth from 11 cats. Seven of the cats were found positive; canine teeth were more frequently positive than molar teeth. Where PCR sequences could be determined, they were identical to those of B. henselae Marseille (four cats), B. henselae Houston (one cat) or similar to those of B. grahamii (one cat). Our study indicates that dental pulp from the teeth of cats, especially the canine teeth, may be used for the PCR detection of Bartonella in animals buried for a year.

Pathogenesis of apical periodontitis and the causes of endodontic failures

Apical periodontitis is a sequel to endodontic infection and manifests itself as the host defense response to microbial challenge emanating from the root canal system. It is viewed as a dynamic encounter between microbial factors and host defenses at the interface between infected radicular pulp and periodontal ligament that results in local inflammation, resorption of hard tissues, destruction of other periapical tissues, and eventual formation of various histopathological categories of apical periodontitis, commonly referred to as periapical lesions. The treatment of apical periodontitis, as a disease of root canal infection, consists of eradicating microbes or substantially reducing the microbial load from the root canal and preventing re-infection by orthograde root filling. The treatment has a remarkably high degree of success. Nevertheless, endodontic treatment can fail. Most failures occur when treatment procedures, mostly of a technical nature, have not reached a satisfactory standard for the control and elimination of infection. Even when the highest standards and the most careful procedures are followed, failures still occur. This is because there are root canal regions that cannot be cleaned and obturated with existing equipments, materials, and techniques, and thus, infection can persist. In very rare cases, there are also factors located within the inflamed periapical tissue that can interfere with post-treatment healing of the lesion. The data on the biological causes of endodontic failures are recent and scattered in various journals. This communication is meant to provide a comprehensive overview of the etio-pathogenesis of apical periodontitis and the causes of failed endodontic treatments that can be visualized in radiographs as asymptomatic post-treatment periapical radiolucencies.

Molecular Detection of Bartonella henselae DNA in the Dental Pulp of 800-Year-Old French Cats

Bartonella species are responsible for chronic bacteremia in domestic cats, which raises a question about the antiquity of the relationship between Bartonella species and cats that act as reservoirs for the organism. The sequencing of Bartonella pap31 and groEL genes from the dental pulp of cats dating from the 13th to 16th centuries identified the presence of B. henselae genotype Houston; the observation of a unique mutation in the results of PCR assays for Bartonella species ruled out modern DNA contamination of the dental pulp samples. We conclude that cats had bacteremia due to B. henselae 800 years ago.

Culture of C. burnetii from the dental pulp of experimentally infected guinea pigs

An experimental model of Q fever in Guinea pigs was studied. Coxiella burnetii was cultured from the dental pulp of infected animals following bacteremia.

Is herpes simplex virus associated with pulp/periapical inflammation?

OBJECTIVES

This study focuses on the detection of herpes simplex virus (HSV) DNA in dental pulp and inflamed periapical tissue.

STUDY DESIGN

Dental pulp tissue (vital and necrotic) and periapical tissue samples were collected under strictly sterile conditions and examined for the presence of HSV DNA. Saliva samples were also examined for the presence of the viral DNA. The polymerase chain reaction assay was used to detect viral DNA. Blood samples were collected, and the enzyme-linked immunosorbent assay (ELISA) for immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies against HSV was carried out.

RESULTS

According to the ELISA test, 19 of the 23 blood samples were IgG-positive and IgM-negative to HSV, whereas 4 were IgG-negative and IgM-negative. HSV DNA was not detected in the tissue and the saliva samples tested.

CONCLUSION

HSV is not present and therefore is probably not involved in the pathology of tooth neural tissue.

Proviral HIV-1 DNA in gingival crevicular fluid of HIV-1-infected patients in various stages of HIV disease

The oral cavity is rarely reported to be a site of human immunodeficiency virus (HIV) transmission, despite detectable virus in saliva and relatively frequent prevalence of periodontal disease in HIV-infected persons yielding increased excretion of mononuclear-cell-enriched gingival fluid. To search for possible sources of HIV in saliva, and using the polymerase chain-reaction technique, we sought the presence and shedding patterns of proviral HIV-1 DNA in gingival crevicular fluid in a group of patients previously determined as HIV-1-seropositive. Periodontal status at the collection sites was monitored by several clinical parameters, including Plaque Index, Gingival Index, probing depth, and clinical attachment loss. Gingival crevicular fluid samples were collected by means of paper points. Proviral HIV-1 DNA was detected in the gingival fluid of 17 out of 35 HIV-1-infected patients. Its detection correlated significantly with higher plasma HIV-1 RNA viral load (p = 0.03) and not with peripheral blood CD4+ cell count, the presence of blood in gingival fluid, or oral lesions. There was a significant correlation between clinical attachment loss at the sites of fluid collection and plasma HIV-1 RNA viral load (p = 0.002), and borderline correlation between the latter and probing depth (p = 0.54) in the group of patients harboring proviral HIV-1 DNA in gingival crevicular fluid. The results of our study suggest that mononuclear cells present in gingival crevicular fluid and harboring proviral HIV-1 DNA could represent a potential source of HIV-1 in the presence or absence of local bleeding, especially in persons with advanced HIV infection and increased loss of clinical attachment.

Detection of Coxiella burnetii DNA in dental pulp during experimental bacteremia

Colonization of dental pulp by blood-borne bacteria in the absence of previous inflammation has been hypothetized but has never been convincingly demonstrated. In order to provide convincing support for this hypothesis we attempted to detect Coxiella burnetii DNA in the dental pulp of bacteremic, intraperitoneally inoculated guinea-pigs by PCR amplification and direct sequencing of two molecular targets. Coxiella burnetii DNA was recovered from 20-50% of the animals depending on the molecular target, from 15-20 days after experimental challenge. These results demonstrated, for the first time, that dental pulp is contaminated by blood-borne bacteria and can be detected by molecular tools.

Detection of human viruses in periodontal pockets using polymerase chain reaction

Even though viruses have been implicated in the etiology of several medical and dental disorders, little or no data are available on the possible involvement of human viruses in the pathogenesis of human periodontal disease. This study investigated the presence of human cytomegalovirus, Epstein-Barr virus, herpes simplex virus, human papillomavirus and human immunodeficiency virus (HIV) in crevicular fluid samples from 30 patients with advanced periodontitis and 26 subjects with gingivitis. Viral identification was performed on direct subgingival samples from 3 diseased sites in each patient using the polymerase chain reaction technique. Seventy-eight percent of advanced periodontitis patients were positive for at least one of the five test viruses. Cytomegalovirus was detected in 60% of the periodontitis patients, Epstein-Barr virus in 30%, herpes simplex virus in 20%, human papillomavirus in 17% and HIV in 7%. Forty percent of the periodontitis patients revealed coinfection by 2 to 5 viruses. Only 31% of the gingivitis subjects showed a positive viral identification in crevicular fluid, and infected individuals only revealed human cytomegalovirus. This study demonstrated that human viruses may occur in periodontitis lesions with relatively high prevalence. The pathogenetic significance of human viruses in destructive periodontal disease needs to be determined.

Practical application of infection control in endodontics

The transmission of infections in an endodontic practice is a significant concern for both patients and dental health care providers. This article offers a review and practical application of infection control methods in the practice of endodontics.