Salivary Outer Membrane Vesicles and DNA Methylation of Small Extracellular Vesicles as Biomarkers for Periodontal Status: A Pilot Study

Bone aging and extracellular vesicles

Bone aging, a major global health concern, is the natural decline in bone mass and strength. Concurrently, extracellular vesicles (EVs), tiny membrane-bound particles produced by cells, have gained recognition for their roles in various physiological processes and age-related diseases. The interaction between EVs and bone aging is of growing interest, particularly their effects on bone metabolism, which become increasingly critical with advancing age. In this review, we explored the biology, types, and functions of EVs and emphasized their regulatory roles in bone aging. We examined the effects of EVs on bone metabolism and highlighted their potential as biomarkers for monitoring bone aging progression. Furthermore, we discussed the therapeutic applications of EVs, including targeted drug delivery and bone regeneration, and addressed the challenges associated with EV-based therapies, including the technical complexities and regulatory issues. We summarized the current research and clinical trials investigating the role of EVs in bone aging and suggested future research directions. These include the potential for personalized medicine using EVs and the integration of EV research with advanced technologies to enhance the management of age-related bone health. This analysis emphasized the transformative potential of EVs in understanding and managing bone aging, thereby marking a significant advancement in skeletal health research.

Role of exosomes in dental and craniofacial regeneration - A review

BACKGROUND

The treatment of congenital deformities, traumatic injuries, infectious diseases, and tumors in the craniomaxillofacial (CMF) region is complex due to the intricate nature of the tissues involved. Conventional treatments such as bone grafts and cell transplantation face limitations, including the need for multiple surgeries, complications, and safety concerns.

OBJECTIVE

This paper aims to provide a comprehensive analysis of the role of exosomes (EXOs) in CMF and dental tissue regeneration and to explore their potential applications in regenerative dental medicine.

METHODS

An extensive review of advancements in tissue engineering, materials sciences, and nanotechnology was conducted to evaluate the development of delivery systems for EXOs-based therapies. The analysis included how EXOs, as nanovesicles released by cells, can be modified to target specific cells or loaded with functional molecules for drug or gene delivery.

RESULTS

EXOs have emerged as a promising alternative to cell transplant therapy, offering a safer method for cell communication and epigenetic control. EXOs transport important proteins and genetic materials, facilitating intercellular communication and delivering therapeutics effectively. The potential of EXOs in personalized medicine, particularly in diagnosing, customizing treatment, and predicting patient responses, is highlighted.

CONCLUSION

EXO-mediated therapy holds significant potential for advancing tissue regeneration, offering targeted, personalized treatment options with reduced side effects. However, challenges in purification, production, and standardized protocols need to be addressed before its clinical application can be fully realized.

Pathogenic mechanisms and potential applications of extracellular vesicles from periodontal pathogens in periodontitis

Periodontitis is a multifactorial disease characterized by chronic destruction of the periodontal supporting tissues and is closely associated with the dysbiosis of the plaque biofilm. It is the leading cause of tooth loss in adults. Bacterial extracellular vesicles (BEVs) are released from bacteria, which range in size from 20 to 400 nm. These vesicles contain various components derived from their parent bacteria, including nucleic acids, proteins, lipids, and other molecules, which facilitate functions such as molecular transfer, metabolic regulation, bacterial interactions, biofilm formation, and immune modulation. BEVs participated in the pathophysiological process of periodontitis. Recently emerging evidence also showed that the contents of EVs in saliva and gingival crevicular fluid (miRNAs, mRNAs, and proteins) could be used as potential biomarkers for periodontitis. While most current research focuses on human-derived components, much less is known about BEVs. Therefore, this review introduces the formation mechanisms and components of BEVs related to periodontitis. Then, this review summarizes the current information about the mechanism, the diagnostic and theraputic value of periodontal pathogen-derived extracellular vesicles in the development of periodontitis. Furthermore, the future challenges of exploring the role of BEVs in periodontitis are also discussed.

Microbial- and host immune cell-derived extracellular vesicles in the pathogenesis and therapy of periodontitis: A narrative review

Periodontitis is a chronic inflammatory disease caused by dysbiotic biofilms and destructive host immune responses. Extracellular vesicles (EVs) are circulating nanoparticles released by microbes and host cells involved in cell-to-cell communication, found in body biofluids, such as saliva and gingival crevicular fluid (GCF). EVs are mainly involved in cell-to-cell communication, and may hold promise for diagnostic and therapeutic purposes. Periodontal research has examined the potential involvement of bacterial- and host-cell-derived EVs in disease pathogenesis, diagnosis, and therapy, but data remains scarce on immune cell- or microbial-derived EVs. In this narrative review, we first provide an overview of the role of microbial and host-derived EVs on disease pathogenesis. Recent studies reveal that Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans-derived outer membrane vesicles (OMVs) can activate inflammatory cytokine release in host cells, while M1 macrophage EVs may contribute to bone loss. Additionally, we summarised current in vitro and pre-clinical research on the utilisation of immune cell and microbial-derived EVs as potential therapeutic tools in the context of periodontal treatment. Studies indicate that EVs from M2 macrophages and dendritic cells promote bone regeneration in animal models. While bacterial EVs remain underexplored for periodontal therapy, preliminary research suggests that P. gingivalis OMVs hold promise as vaccine candidates. Finally, we acknowledge the current limitations present in the field of translating immune cell derived EVs and microbial derived EVs in periodontology. It is concluded that microbial and host immune cell-derived EVs have a role in periodontitis pathogenesis and hence may be useful for studying disease pathophysiology, and as diagnostic and treatment monitoring biomarkers.

Insight into the potential of algorithms using AI technology as in vitro diagnostics utilizing microbial extracellular vesicles

Recently, the microbiome has been gaining significant attention in the healthcare sector as a next-generation factor. However, there remains a substantial gap in our understanding of the fundamental mechanisms of microbes, particularly regarding the effector microbial products exchanged between the microbiota and the host. Consequently, research on microbial extracellular vesicles (MEVs) has increased. MEVs, which are nano-sized, can circulate throughout the body and penetrate the bloodstream, carrying diverse information. Consequently, they are increasingly being utilized in medical applications. Additionally, AI technologies are being utilized in medicine. The combination of MEVs and AI technology is being explored for the development of algorithm-based in vitro diagnostics (IVD). Therefore, this study aims to review the integration of MEVs and AI technology as diagnostic tools for personalized medicine. This paper reviewed the MEV-based algorithms developed by a variety of human samples and AI technology. Additionally, most of MEV-based diagnostic models showed higher clinical performance. Several important factors are crucial for accurate diagnosis. First, optimizing sample types according to specific diseases is essential. Second, AI technology with higher diagnostic power yields more accurate results. Finally, incorporating additional markers can enhance diagnostic power. However, applying this tool in situ faces several limitations, including method standardization, sample size, and analysis techniques. In the future, we anticipate that research on MEVs will advance our understanding of their role in disease and establish the foundation for precision medicine strategies.

Microvesicle-eluting nano-engineered implants influence inflammatory response of keratinocytes

Besides enhancing osseo- and soft tissue integration, modulating inflammation at the implant site is also crucial for dental implant success. Uncontrolled peri-implant inflammation can cause significant loss of surrounding tissue and implant failure. It was recently shown that microvesicles (MVs), a less-studied type of extracellular vesicles, play a crucial role in cell-to-cell communication and may modulate angiogenesis and inflammatory response. The effect of MVs on regulating inflammation at an implant site, however, remains unexplored. In the current study, MVs were isolated and characterised from human primary gingival fibroblasts (hGFs) and loaded within titania nanotubes (TNTs, fabricated via anodisation on 3D Ti wire implants) towards their local release. The modified implants were characterised using SEM and confocal imaging to confirm the loading and local release of MVs from TNTs. In vitro studies demonstrated the internalisation of hGFs-MVs by human gingival keratinocytes (OKF6/TERT2 cell line), which caused a significant reduction in the production of pro-inflammatory cytokines. The results support MVs-releasing TNTs as a promising implant surface modification strategy to reduce inflammation, paving the way for further advancements in therapeutic dental implants.

Extracellular vesicles: immunomodulation, diagnosis, and promising therapeutic roles for rheumatoid arthritis

Extracellular vesicles (EV) can be produced as part of pathology and physiology with increased amounts in pathological conditions. EVs can carry and transfer cargo such as proteins, nucleic acids, and lipids to target cells and mediate intercellular communication resulting in modulation of gene expression, signaling pathways, and phenotype of recipient cells. EVs greatly influence the extracellular environment and the immune response. Their immunomodulatory properties are crucial in rheumatoid arthritis (RA), a condition marked by dysregulated immune response. EVs can modulate the functions of innate and adaptive immune cells in RA pathogenesis. Differentially expressed EV-associated molecules in RA, such as microRNAs (miRNAs), long-noncoding RNAs (lncRNAs), messenger RNAs (mRNAs) and proteins are promising markers to diagnose the disease. miRNA, lncRNA, and circular RNA (circRNA) cargos in EV regulate inflammation and the pathogenic functions of RA fibroblast-like synoviocytes (RA-FLS). Downregulated molecules in RA tissue and drugs can be encapsulated in EVs for RA therapy. This review provides an updated overview of EVs' immunomodulatory, diagnostic, and therapeutic roles, particularly emphasizing mesenchymal stem cell-derived EVs (MSC-EVs).

The detection, biological function, and liquid biopsy application of extracellular vesicle-associated DNA

Cell-derived extracellular vesicles (EVs), which carry diverse biomolecules such as nucleic acids, proteins, metabolites, and lipids reflecting their cell of origin, are released under both physiological and pathological conditions. EVs have been demonstrated to mediate cell-to-cell communication and serve as biomarkers. EV-associated DNA (EV-DNA) comprises genomic and mitochondrial DNA (i.e., gDNA and mtDNA) fragments. Some studies have revealed that EV-DNA can represent the full nuclear genome and mitochondrial genome of parental cells. Furthermore, DNA fragments loaded into EVs are stable and can be transferred to recipient cells to regulate their biological functions. In this review, we summarized and discussed EV-DNA research advances with an emphasis on EV-DNA detection at the population-EV and single-EV levels, gene transfer-associated biological functions, and clinical applications as biomarkers for disease liquid biopsy. We hope that this review will provide potential directions or guidance for future EV-DNA investigations.

The emerging role of bacterial extracellular vesicles in human cancers

Bacterial extracellular vesicles (BEVs) have emerged as pivotal mediators between bacteria and host. In addition to being crucial players in host homeostasis, they have recently been implicated in disease pathologies such as cancer. Hence, the study of BEVs represents an intriguing and rapidly evolving field with substantial translational potential. In this review, we briefly introduce the fundamentals of BEV characteristics, cargo and biogenesis. We emphatically summarize the current relationship between BEVs across various cancer types, illustrating their role in tumorigenesis, treatment responses and patient survival. We further discuss the inherent advantages of BEVs, such as stability, abundance and specific cargo profiles, that make them attractive candidates for non-invasive diagnostic and prognostic approaches. The review also explores the potential of BEVs as a strategy for cancer therapy, considering their ability to deliver therapeutic agents, modulate the tumour microenvironment (TME) and elicit immunomodulatory responses. Understanding the clinical significance of BEVs may lead to the development of better-targeted and personalized treatment strategies. This comprehensive review evaluates the current progress surrounding BEVs and poses questions to encourage further research in this emerging field to harness the benefits of BEVs for their full potential in clinical applications against cancer.

DNA methylation and its potential roles in common oral diseases

Oral diseases are among the most common diseases worldwide and are associated with systemic illnesses, and the rising occurrence of oral diseases significantly impacts the quality of life for many individuals. It is crucial to detect and treat these conditions early to prevent them from advancing. DNA methylation is a fundamental epigenetic process that contributes to a variety of diseases including various oral diseases. Taking advantage of its reversibility, DNA methylation becomes a viable therapeutic target by regulating various cellular processes. Understanding the potential role of this DNA alteration in oral diseases can provide significant advances and more opportunities for diagnosis and therapy. This article will review the biology of DNA methylation, and then mainly discuss the key findings on DNA methylation in oral cancer, periodontitis, endodontic disease, oral mucosal disease, and clefts of the lip and/or palate in the background of studies on global DNA methylation and gene-specific DNA methylation.

Periodontal disease and emerging point-of-care technologies for its diagnosis

Periodontal disease (PD), a chronic inflammatory disorder that damages the tooth and its supporting components, is a common global oral health problem. Understanding the intricacies of these disorders, from gingivitis to severe PD, is critical for efficient treatment, diagnosis, and prevention in dental care. Periodontal biosensors and biomarkers are critical in improving oral health diagnostic skills. Clinicians may accomplish early identification, tailored therapy, and efficient tracking of periodontal diseases by using these technologies, ushering in a new age of accurate oral healthcare. Traditional periodontitis diagnostic methods frequently rely on physical probing and visual examinations, necessitating the development of point-of-care (POC) devices. As periodontal disorders necessitate more precise and rapid diagnosis, incorporating novel innovations in biosensors and biomarkers becomes increasingly crucial. These innovations improve our capacity to diagnose, monitor, and adapt periodontal therapies, bringing in the next phase of customized and effective dental healthcare. The review discusses the characteristics and stages of PD, clinical treatment techniques, prominent biomarkers and infection-associated factors that may be employed to determine PD, biomedical sensing, and POC appliances that have been created so far to diagnose stages of PD and its progression profile, as well as predicting future developments in this field.

Effect of non-surgical periodontal therapy on salivary histone deacetylases expression: A prospective clinical study

AIM

To evaluate the effect of non-surgical periodontal therapy (NSPT) on salivary histone deacetylases (HDACs) gene expression in patients with Stage III-IV periodontitis at baseline and at 3 and 6 months post NSPT treatment.

MATERIALS AND METHODS

Twenty patients completed the study. Periodontitis (as well as the corresponding staging and grading) was diagnosed according to the 2017 World Workshop Classification. Clinical measures were recorded and whole unstimulated saliva was collected at baseline and at 3 and 6 months after NSPT. The expression of 11 HDACs was determined using reverse-transcription PCR, and the respective changes over time were evaluated.

RESULTS

Six months after NSPT, significant improvements in all clinical periodontal parameters were observed, concomitant with significant up-regulation of HDAC2, 4, 6, 8, 9 and 11 expressions. Subgroup analyses of non-responders and responders revealed no significant differences in HDACs mRNA expression between groups at any time point.

CONCLUSIONS

This prospective clinical study identified longitudinal changes in salivary HDACs expression in response to NSPT, which provides new insights into the epigenetic mechanisms underlying the pathobiology of periodontitis and creates avenues for the discovery of novel biomarkers.

Unveiling clinical applications of bacterial extracellular vesicles as natural nanomaterials in disease diagnosis and therapeutics

Bacterial extracellular vesicles (BEVs) are naturally occurring bioactive membrane-bound nanoparticles released by both gram-negative and gram-positive bacterial species, exhibiting a multifaceted role in mediating host-microbe interactions across various physiological conditions. Increasing evidence supports BEVs as essential mediators of cell-to-cell communicaiton, influencing bacterial pathogenicity, disease mechanisms, and modulating the host immune response. However, the extent to which these BEV-mediated actions can be leveraged to predict disease onset, guide treatment strategies, and determine clinical outcomes remains uncertain, particularly in terms of their clinical translation potentials. This review briefly describes BEV biogenesis and their internalisation by recipient cells and summarises methods for isolation and characterization, essential for understanding their composition and cargo. Further, it discusses the potential of biofluid-associated BEVs as biomarkers for various diseases, spanning both cancer and non-cancerous conditions. Following this, we outline the ongoing human clinical trials of using BEVs for vaccine development. In addition to disease diagnostics, this review explores the emerging research of using natural or engineered BEVs as smart nanomaterials for applications in anti-cancer therapy and bone regeneration. This discussion extends to key factors for unlocking the clinical potential of BEVs, such as standardization of BEV isolation and characterisation, as well as other hurdles in translating these findings to the clinical setting. We propose that addressing these hurdles through collaborative research efforts and well-designed clinical trials holds the key to fully harnessing the clinical potential of BEVs. As this field advances, this review suggests that BEV-based nanomedicine has the potential to revolutionize disease management, paving the way for innovative diagnosis, therapeutics, and personalized medicine approaches. STATEMENT OF SIGNIFICANCE: Extracellular vesicles (EVs) from both host cells and bacteria serve as multifunctional biomaterials and are emerging in the fields of biomedicine, bioengineering, and biomaterials. However, the majority of current studies focus on host-derived EVs, leaving a gap in comprehensive research on bacteria-derived EVs (BEVs). Although BEVs offer an attractive option as nanomaterials for drug delivery systems, their unique nanostructure and easy-to-modify functions make them a potential method for disease diagnosis and treatment as well as vaccine development. Our work among the pioneering studies investigating the potential of BEVs as natural nanobiomaterials plays a crucial role in both understanding the development of diseases and therapeutic interventions.

New frontiers in salivary extracellular vesicles: transforming diagnostics, monitoring, and therapeutics in oral and systemic diseases

Salivary extracellular vesicles (EVs) have emerged as key tools for non-invasive diagnostics, playing a crucial role in the early detection and monitoring of diseases. These EVs surpass whole saliva in biomarker detection due to their enhanced stability, which minimizes contamination and enzymatic degradation. The review comprehensively discusses methods for isolating, enriching, quantifying, and characterizing salivary EVs. It highlights their importance as biomarkers in oral diseases like periodontitis and oral cancer, and underscores their potential in monitoring systemic conditions. Furthermore, the review explores the therapeutic possibilities of salivary EVs, particularly in personalized medicine through engineered EVs for targeted drug delivery. The discussion also covers the current challenges and future prospects in the field, emphasizing the potential of salivary EVs in advancing clinical practice and disease management.

3D bioprinted small extracellular vesicles from periodontal cells enhance mesenchymal stromal cell function

Recent research indicates that combining 3D bioprinting and small extracellular vesicles (sEVs) offers a promising 'cell-free' regenerative medicine approach for various tissue engineering applications. Nonetheless, the majority of existing research has focused on bioprinting of sEVs sourced from cell lines. There remains a notable gap in research regarding the bioprinting of sEVs derived from primary human periodontal cells and their potential impact on ligamentous and osteogenic differentiation. Here, we investigated the effect of 3D bioprinted periodontal cell sEVs constructs on the differentiation potential of human buccal fat pad-derived mesenchymal stromal cells (hBFP-MSCs). Periodontal cell-derived sEVs were enriched by size exclusion chromatography (SEC) with particle-shaped morphology, and characterized by being smaller than 200 nm in size and CD9/CD63/CD81 positive, from primary human periodontal ligament cells (hPDLCs) and human gingival fibroblasts (hGFs). The sEVs were then 3D bioprinted in 10 % gelatin methacryloyl (GelMA) via microextrusion bioprinting. Release of sEVs from bioprinted constructs was determined by DiO-labelling and confocal imaging, and CD9 ELISA. Attachment and ligament/osteogenic/cementogenic differentiation of hBFP-MSCs was assessed on bioprinted GelMA, without and with sEVs (GelMA/hPDLCs-sEVs and GelMA/hGFs-sEVs), scaffolds. hBFP-MSCs seeded on the bioprinted sEVs constructs spread well with significantly enhanced focal adhesion, mechanotransduction associated gene expression, and ligament and osteogenesis/cementogenesis differentiation markers in GelMA/hPDLCs-sEVs, compared to GelMA/hGFs-sEVs and GelMA groups. A 2-week osteogenic and ligamentous differentiation showed enhanced ALP staining, calcium formation and toluidine blue stained cells in hBFP-MSCs on bioprinted GelMA/hPDLCs-sEVs constructs compared to the other two groups. The proof-of-concept data from this study supports the notion that 3D bioprinted GelMA/hPDLCs-sEVs scaffolds promote cell attachment, as well as ligamentous, osteogenic and cementogenic differentiation, of hBFP-MSCs in vitro.

Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches

Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its 'Minimal Information for Studies of Extracellular Vesicles', which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly.

Understanding exosomes: Part 3-therapeutic + diagnostic potential in dentistry

Exosomes are the smallest subset of extracellular signaling vesicles secreted by most cells with the ability to communicate with other tissues and cell types over long distances. Their use in regenerative medicine has gained tremendous momentum recently due to their ability to be utilized as therapeutic options for a wide array of various diseases. Over 5000 publications are currently being published on this topic yearly, many of which in the dental space. This extensive review article is the first scoping review aimed at summarizing all therapeutic uses of exosomes in regenerative dentistry. A total of 944 articles were identified as using exosomes in the dental field for either their regenerative/therapeutic potential or for diagnostic purposes derived from the oral cavity. In total, 113 research articles were selected for their regenerative potential (102 in vitro, 60 in vivo, 50 studies included both). Therapeutic exosomes were most commonly derived from dental pulps, periodontal ligament cells, gingival fibroblasts, stem cells from exfoliated deciduous teeth, and the apical papilla which have all been shown to facilitate the regenerative potential of a number of tissues including bone, cementum, the periodontal ligament, nerves, aid in orthodontic tooth movement, and relieve temporomandibular joint disorders, among others. Results demonstrate that the use of exosomes led to positive outcomes in 100% of studies. In the bone field, exosomes were found to perform equally as well or better than rhBMP2 while significantly reducing inflammation. Periodontitis animal models were treated with simple gingival injections of exosomes and benefits were even observed when the exosomes were administered intravenously. Exosomes are much more stable than growth factors and were shown to be far more resistant against degradation by periodontal pathogens found routinely in a periodontitis environment. Comparative studies in the field of periodontal regeneration found better outcomes for exosomes even when compared to their native parent stem cells. In total 47 diagnostic studies revealed a role for salivary/crevicular fluid exosomes for the diagnosis of birth defects, cardiovascular disease, diabetes, gingival recession detection, gingivitis, irritable bowel syndrome, neurodegenerative disease, oral lichen planus, oral squamous cell carcinoma, oropharyngeal cancer detection, orthodontic root resorption, pancreatic cancer, periodontitis, peri-implantitis, Sjögren syndrome, and various systemic diseases. Hence, we characterize the exosomes as possessing "remarkable" potential, serving as a valuable tool for clinicians with significant advantages.

Saliva biofilm-derived outer membrane vesicles regulate biofilm formation and immune response of oral epithelial cells on titanium surfaces

OBJECTIVES

While the significant roles of outer membrane vesicles (OMVs) from individual oral bacterial species in bacterial-host interactions are known, the involvement of saliva biofilm-derived OMVs in peri-implant disease pathogenesis remains unclear. This study aimed to investigate the effect of saliva biofilm-derived OMVs on regulating saliva biofilm formation and modulating the immune response of the epithelial cells on titanium surfaces.

MATERIALS AND METHODS

Saliva derived biofilms were cultured on tissue culture plates (TCP) for 4 days using pooled saliva from four healthy donors. OMVs secreted from the TCP bound biofilm (referred to as OMVs or healthy saliva biofilm OMVs) were enriched using the size-exclusion chromatography method. We then evaluated the effects of these OMVs on the viability, metabolic activity, and the presence of oral pathogens in saliva biofilm grown on titanium discs for 24 h and 72 h. Furthermore, the impact of OMVs on the mRNA expression and inflammatory cytokines [interleukin (IL)-6, IL-1α, and monocyte chemoattractant protein-1 (MCP-1)] in human oral epithelial cells (OKF6/TERT-2) was investigated using RT-qPCR and enzyme-linked immunosorbent assay (ELISA), respectively.

RESULTS

Healthy saliva biofilm OMVs improved the biomass and activity of saliva biofilm cultured on the titanium surfaces, with inhibited Porphyromonas gingivalis and Fusobacterium nucleatum, and enhanced Streptococcus mutans expression. Additionally, OMVs increased pro-inflammatory cytokine IL-6 mRNA and IL-6 cytokine expression in human oral epithelial cells. However, IL-1α and MCP-1 cytokines were inhibited 24-hour post-incubation with OMVs.

CONCLUSION

Healthy saliva biofilm derived OMVs regulate the activity and pathogen composition of biofilms formed on titanium, while modulating the secretion of pro-inflammation factors of oral epithelial cells grown on titanium surfaces.

CLINICAL RELEVANCE

Healthy saliva biofilm OMVs may regulate the early biofilm formation on abutment surfaces and modulate epithelial cell immune response, which may alter the peri-implant niche and participate in the pathogenesis of peri-implant disease.

Liposomal Antibiotic Booster Potentiates Carbapenems for Combating NDMs-Producing Escherichia coli

Infections caused by Enterobacterales producing New Delhi Metallo-β-lactamases (NDMs), Zn(II)-dependent enzymes hydrolyzing carbapenems, are difficult to treat. Depriving Zn(II) to inactivate NDMs is an effective solution to reverse carbapenems resistance in NDMs-producing bacteria. However, specific Zn(II) deprivation and better bacterial outer membrane penetrability in vivo are challenges. Herein, authors present a pathogen-primed liposomal antibiotic booster (M-MFL@MB), facilitating drugs transportation into bacteria and removing Zn(II) from NDMs. M-MFL@MB introduces bismuth nanoclusters (BiNCs) as a storage tank of Bi(III) for achieving ROS-initiated Zn(II) removal. Inspired by bacteria-specific maltodextrin transport pathway, meropenem-loaded BiNCs are camouflaged by maltodextrin-cloaked membrane fusion liposome to cross the bacterial envelope barrier via selectively targeting bacteria and directly outer membrane fusion. This fusion disturbs bacterial membrane homeostasis, then triggers intracellular ROS amplification, which activates Bi(III)-mediated Zn(II) replacement and meropenem release, realizing more precise and efficient NDMs producer treatment. Benefiting from specific bacteria-targeting, adequate drugs intracellular accumulation and self-activation Zn(II) replacement, M-MFL@MB rescues all mice infected by NDM producer without systemic side effects. Additionally, M-MFL@MB decreases the bacterial outer membrane vesicles secretion, slowing down NDMs producer's transmission by over 35 times. Taken together, liposomal antibiotic booster as an efficient and safe tool provides new strategy for tackling NDMs producer-induced infections.

Extracellular vesicles from periodontal pathogens regulate hepatic steatosis via Toll-like receptor 2 and plasminogen activator inhibitor-1

Plasminogen activator inhibitor-1 (PAI-1) is associated with nonalcoholic fatty liver disease (NAFLD) by lipid accumulation in the liver. In this study, we showed that extracellular vesicles (EVs) from the periodontal pathogens Filifactor alocis and Porphyromonas gingivalis induced steatosis by inducing PAI-1 in the liver and serum of mice fed a low-fat diet. PAI-1 induction was not observed in TLR2-/- mice. When tested using HEK-Blue hTLR2 cells, human TLR2 reporter cells, the TLR2-activating ability of serum from NAFLD patients (n = 100) was significantly higher than that of serum from healthy subjects (n = 100). Correlation analysis confirmed that PAI-1 levels were positively correlated with the TLR2-activating ability of serum from NAFLD patients and healthy subjects. Amphiphilic molecules in EVs were involved in PAI-1 induction. Our data demonstrate that the TLR2/PAI-1 axis is important for hepatic steatosis by EVs of periodontal pathogens.

Immunoaffinity-enriched salivary small extracellular vesicles in periodontitis

Aim

aliva extracellular vesicles (EVs) serve as a significant reservoir of biomarkers that may be of clinical use in disease diagnosis. Saliva, however, contains EVs of both host- and bacterial- origin. Identifying suitable EVs for disease diagnosis involves enriching host EVs and limiting non-host contamination with effective isolation methods. The objectives of this research were: (1) to evaluate the salivary EVs enrichment in 12 periodontally healthy patients by two different methods: size exclusion chromatography (SEC) and bead-based immunoaffinity capture (EXO-NET®); (2) to analyze the variance expression of inflammatory cytokines in EXO-NET-enriched EVs, comparing individuals with periodontitis (n = 20) to non-periodontitis (n = 12).

Methods

Whole unstimulated saliva samples were collected from 12 periodontally healthy and 20 periodontitis patients. EVs were isolated from the 12 non-periodontitis patients using SEC (referred to as SEC-EVs) and EXO-NET (referred to as EXO-NET EVs), after which their total protein content, 37 EV surface markers, and bacterial pathogens expression were compared. Subsequently, the inflammatory cytokines expression levels (interleukin-IL-6, IL-1β, IL-8, and IL-10) in EXO-NET EVs were measured for non-periodontitis and periodontitis.

Results

EXO-NET EVs contained more EV-specific protein and substantially higher expression of EV surface markers (CD9, CD81, CD63), but less pathogenic DNA was detected compared to that in SEC-EVs. Additionally, EXO-NET EVs from periodontitis patients contained higher amounts of IL-6 and IL-8, and decreased IL-10, compared to those from non-periodontitis patients.

Conclusion

The findings suggest that immunoaffinity capture (EXO-NET) is a dependable method for salivary EVs enrichment, resulting in a higher yield of host EVs with reduced bacterial DNA detection compared to SEC. Furthermore, the research proposes that immunoaffinity capture enriched EVs can function as biomarkers for periodontitis, demonstrated by an increased expression of proinflammatory cytokines from periodontitis patients.

Salivary Extracellular Vesicles: Biomarkers and Beyond in Human Diseases

Extracellular vesicles, as bioactive molecules, have been extensively studied. There are abundant studies in the literature on their biogenesis, secretion, structure, and content, and their roles in pathophysiological processes. Extracellular vesicles have been reviewed as biomarkers for use in diagnostic tools. Saliva contains many extracellular vesicles, and compared with other body fluids, it is easier to obtain in a non-invasive way, making its acquisition more easily accepted by patients. In recent years, there have been numerous new studies investigating the role of salivary extracellular vesicles as biomarkers. These studies have significant implications for future clinical diagnosis. Therefore, in this paper, we summarize and review the potential applications of salivary extracellular vesicles as biomarkers, and we also describe their other functions (e.g., hemostasis, innate immune defense) in both oral and non-oral diseases.

Effects of periodontal cells-derived extracellular vesicles on mesenchymal stromal cell function

OBJECTIVE

To enrich and compare three extracellular vesicles-EV subtypes (apoptotic bodies, microvesicles and small EV) from three periodontal cells (periodontal ligament cells-PDLCs, alveolar bone-derived osteoblasts-OBs and gingival fibroblasts-GFs), and assess uptake and cell function changes in buccal fat pad-derived mesenchymal stromal cells (BFP-MSCs).

BACKGROUND

Periodontal cells such as PDLCs, OBs and GFs have the potential to enhance bone and periodontal regeneration, but face significant challenges, such as the regulatory and cost implications of in vitro cell culture and storage. To address these challenges, it is important to explore alternative 'cell-free' strategies, such as extracellular vesicles which have emerged as promising tools in regenerative medicine, to facilitate osteogenic differentiation and bone regeneration.

METHODS AND MATERIALS

Serial centrifuges at 2600 and 16 000 g were used to isolate apoptotic bodies and microvesicles respectively. Small EV-sEV was enriched by our in-house size exclusion chromatography (SEC). The cellular uptake, proliferation, migration and osteogenic/adipogenic differentiation genes were analysed after EVs uptake in BFP-MSCs.

RESULTS

Three EV subtypes were enriched and characterised by morphology, particle size and EV-associated protein expression-CD9. Cellular uptake of the three EVs subtypes was observed in BFP-MSCs for up to 7 days. sEV from the three periodontal cells promoted proliferation, migration and osteogenic gene expression. hOBs-sEV showed superior levels of osteogenesis markers compared to that hPDLCs-sEV and hGFs-sEV, while hOBs-16k EV promoted adipogenic gene expression compared to that from hPDLCs and hGFs.

CONCLUSIONS

Our proof-of-concept data demonstrate that hOBs-sEV might be an alternative cell-free therapeutic for bone tissue engineering.

Porphyromonas gingivalis outer membrane vesicles in cerebral ventricles activate microglia in mice

OBJECTIVE

Porphyromonas gingivalis (Pg) is thought to be involved in the progression of Alzheimer's disease (AD). Whether Pg or its contents can reach the brain and directly affect neuropathology is, however, unknown. Here, we investigated whether outer membrane vesicles (OMVs) of Pg translocate to the brain and induce the pathogenic features of AD.

MATERIAL AND METHODS

Pg OMVs were injected into the abdominal cavity of mice for 12 weeks. Pg OMV translocation to the brain was detected by immunohistochemistry using an anti-gingipain antibody. Tau protein and microglial activation in the mouse brain were examined by western blotting and immunohistochemistry. The effect of gingipains on inflammation was assessed by real-time polymerase chain reaction using human microglial HMC3 cells.

RESULTS

Gingipains were detected in the region around cerebral ventricles, choroid plexus, and ventricular ependymal cells in Pg OMV-administered mice. Tau and phosphorylated Tau protein increased and microglia were activated. Pg OMVs also increased the gene expression of proinflammatory cytokines in HMC3 cells in a gingipain-dependent manner.

CONCLUSION

Pg OMVs, including gingipains, can reach the cerebral ventricle and induce neuroinflammation by activating microglia. Pg OMVs may provide a better understanding of the implications of periodontal diseases in neurodegenerative conditions such as AD.

Engineered adult stem cells: Current clinical trials status of disease treatment

Regenerative medicine is an interdisciplinary field involving the process of replacing and regenerating cells/tissues or organs by integrating medicine, science, and engineering principles to enhance the intrinsic regenerative capacity of the host. Recently, engineered adult stem cells have gained attention for their potential use in regenerative medicine by reducing inflammation and modulating the immune system. This chapter introduces adult stem cell engineering and chimeric antigen receptor T cells (CAR T) gene therapy and summarises current engineered stem cell- and extracellular vesicles (EVs)-focused clinical trial studies that provide the basis for the proposal of a personalised medicine approach to diseases diagnosis and treatment.

Impact of Circulating Cell-Free DNA (cfDNA) as a Biomarker of the Development and Evolution of Periodontitis

In the last few decades, circulating cell-free DNA (cfDNA) has been shown to have an important role in cell apoptosis or necrosis, including in the development and evolution of several tumors and inflammatory diseases in humans. In this regard, periodontitis, a chronic inflammatory disease that can induce the destruction of supporting components of the teeth, could represent a chronic inflammatory stimulus linked to a various range of systemic inflammatory diseases. Recently, a possible correlation between periodontal disease and cfDNA has been shown, representing new important diagnostic-therapeutic perspectives. During the development of periodontitis, cfDNA is released in biological fluids such as blood, saliva, urine and other body fluids and represents an important index of inflammation. Due to the possibility of withdrawing some of these liquids in a non-invasive way, cfDNA could be used as a possible biomarker for periodontal disease. In addition, discovering a proportional relationship between cfDNA levels and the severity of periodontitis, expressed through the disease extent, could open the prospect of using cfDNA as a possible therapeutic target. The aim of this article is to report what researchers have discovered in recent years about circulating cfDNA in the development, evolution and therapy of periodontitis. The analyzed literature review shows that cfDNA has considerable potential as a diagnostic, therapeutic biomarker and therapeutic target in periodontal disease; however, further studies are needed for cfDNA to be used in clinical practice.

Extracellular vesicles: cross-organismal RNA trafficking in plants, microbes, and mammalian cells

Extracellular vesicles (EVs) are membrane-enclosed nanometer-scale particles that transport biological materials such as RNAs, proteins, and metabolites. EVs have been discovered in nearly all kingdoms of life as a form of cellular communication across different cells and between interacting organisms. EV research has primarily focused on EV-mediated intra-organismal transport in mammals, which has led to the characterization of a plethora of EV contents from diverse cell types with distinct and impactful physiological effects. In contrast, research into EV-mediated transport in plants has focused on inter-organismal interactions between plants and interacting microbes. However, the overall molecular content and functions of plant and microbial EVs remain largely unknown. Recent studies into the plant-pathogen interface have demonstrated that plants produce and secrete EVs that transport small RNAs into pathogen cells to silence virulence-related genes. Plant-interacting microbes such as bacteria and fungi also secrete EVs which transport proteins, metabolites, and potentially RNAs into plant cells to enhance their virulence. This review will focus on recent advances in EV-mediated communications in plant-pathogen interactions compared to the current state of knowledge of mammalian EV capabilities and highlight the role of EVs in cross-kingdom RNA interference.

Bioprinting extracellular vesicles as a "cell-free" regenerative medicine approach

Regenerative medicine involves the restoration of tissue or organ function via the regeneration of these structures. As promising regenerative medicine approaches, either extracellular vesicles (EVs) or bioprinting are emerging stars to regenerate various tissues and organs (i.e., bone and cardiac tissues). Emerging as highly attractive cell-free, off-the-shelf nanotherapeutic agents for tissue regeneration, EVs are bilayered lipid membrane particles that are secreted by all living cells and play a critical role as cell-to-cell communicators through an exchange of EV cargos of protein, genetic materials, and other biological components. 3D bioprinting, combining 3D printing and biology, is a state-of-the-art additive manufacturing technology that uses computer-aided processes to enable simultaneous patterning of 3D cells and tissue constructs in bioinks. Although developing an effective system for targeted EVs delivery remains challenging, 3D bioprinting may offer a promising means to improve EVs delivery efficiency with controlled loading and release. The potential application of 3D bioprinted EVs to regenerate tissues has attracted attention over the past few years. As such, it is timely to explore the potential and associated challenges of utilizing 3D bioprinted EVs as a novel "cell-free" alternative regenerative medicine approach. In this review, we describe the biogenesis and composition of EVs, and the challenge of isolating and characterizing small EVs - sEVs (< 200 nm). Common 3D bioprinting techniques are outlined and the issue of bioink printability is explored. After applying the following search strategy in PubMed: "bioprinted exosomes" or "3D bioprinted extracellular vesicles", eight studies utilizing bioprinted EVs were found that have been included in this scoping review. Current studies utilizing bioprinted sEVs for various in vitro and in vivo tissue regeneration applications, including angiogenesis, osteogenesis, immunomodulation, chondrogenesis and myogenesis, are discussed. Finally, we explore the current challenges and provide an outlook on possible refinements for bioprinted sEVs applications.

Salivary histone deacetylase in periodontal disease: A cross-sectional pilot study

OBJECTIVE

The objective of the study was to profile the expression level of histone deacetylase enzymes (HDACs) in human saliva in periodontal health, gingivitis and periodontitis.

BACKGROUND

HDACs are epigenetic modulators and a group of enzymes that catalyse the removal of acetyl functional groups from the lysine residues of both histone and nonhistone proteins. HDACs have been detected in gingival tissues and may provide valuable insight into the periodontal inflammatory response. However, no studies have investigated the expression of HDACs in saliva from periodontitis-affected individuals and their capacity for periodontal diagnostics and screening.

MATERIALS AND METHODS

Whole unstimulated saliva was collected from 53 participants (17 healthy, 14 gingivitis and 22 stages III/IV periodontitis). The expression of 11 HDACs in saliva samples was determined using RT-qPCR and diagnostic power was calculated using the receiver operating characteristic (ROC) curves and area under the ROC Curve (AUC).

RESULTS

Relative to health, the expression of HDAC4, 8 and 10 was downregulated in gingivitis, and the expression of HDAC4, 6, 8 and 9 was downregulated in periodontitis. Increased HDAC1 and decreased HDAC9 expression were observed in periodontitis compared to gingivitis. Higher HDAC1 and lower HDAC6 and 9 expression was observed in periodontitis compared to non-periodontitis (combining health and gingivitis). Expression of HDAC3, 4, 8, 9 and 10 was significantly decreased in periodontal disease (combining gingivitis and periodontitis) compared to health. HDAC4 and 8 exhibited an excellent diagnostic capacity for distinguishing gingivitis and periodontal disease from health (AUC 0.79-0.86). HDAC9 showed an acceptable power in discriminating periodontitis from health, gingivitis and non-periodontitis (AUC 0.76-0.80). Salivary HDAC enzyme activity showed no significant difference among the groups.

CONCLUSION

This pilot study has demonstrated the differential expression of HDACs in human saliva for the first time and identified HDAC4, 8 and 9 as potential biomarkers in periodontal diagnosis.

Salivary Exosomes in Health and Disease: Future Prospects in the Eye

Exosomes are a group of vesicles that package and transport DNA, RNA, proteins, and lipids to recipient cells. They can be derived from blood, saliva, urine, and/or other biological tissues. Their impact on several diseases, such as neurodegenerative, autoimmune, and ocular diseases, have been reported, but not fully unraveled. The exosomes that are derived from saliva are less studied, but offer significant advantages over exosomes from other sources, due to their accessibility and ease of collection. Thus, their role in the pathophysiology of diseases is largely unknown. In the context of ocular diseases, salivary exosomes have been under-utilized, thus creating an enormous gap in the literature. The current review discusses the state of exosomes research on systemic and ocular diseases and highlights the role and potential of salivary exosomes as future ocular therapeutic vehicles.

The Applications and Potentials of Extracellular Vesicles from Different Cell Sources in Periodontal Regeneration

Periodontitis is a chronic infectious disease worldwide that can cause damage to periodontal supporting tissues including gingiva, bone, cementum and periodontal ligament (PDL). The principle for the treatment of periodontitis is to control the inflammatory process. Achieving structural and functional regeneration of periodontal tissues is also essential and remains a major challenge. Though many technologies, products, and ingredients were applied in periodontal regeneration, most of the strategies have limited outcomes. Extracellular vesicles (EVs) are membranous particles with a lipid structure secreted by cells, containing a large number of biomolecules for the communication between cells. Numerous studies have demonstrated the beneficial effects of stem cell-derived EVs (SCEVs) and immune cell-derived EVs (ICEVs) on periodontal regeneration, which may be an alternative strategy for cell-based periodontal regeneration. The production of EVs is highly conserved among humans, bacteria and plants. In addition to eukaryocyte-derived EVs (CEVs), a growing body of literature suggests that bacterial/plant-derived EVs (BEVs/PEVs) also play an important role in periodontal homeostasis and regeneration. The purpose of this review is to introduce and summarize the potential therapeutic values of BEVs, CEVs and PEVs in periodontal regeneration, and discuss the current challenges and prospects for EV-based periodontal regeneration.

Saliva - a new opportunity for fluid biopsy

Saliva is a complex biological fluid with a variety of biomolecules, such as DNA, RNA, proteins, metabolites and microbiota, which can be used for the screening and diagnosis of many diseases. In addition, saliva has the characteristics of simple collection, non-invasive and convenient storage, which gives it the potential to replace blood as a new main body of fluid biopsy, and it is an excellent biological diagnostic fluid. This review integrates recent studies and summarizes the research contents of salivaomics and the research progress of saliva in early diagnosis of oral and systemic diseases. This review aims to explore the value and prospect of saliva diagnosis in clinical application.

Emerging role of microbiota derived outer membrane vesicles to preventive, therapeutic and diagnostic proposes

The role of gut microbiota and its products in human health and disease is profoundly investigated. The communication between gut microbiota and the host involves a complicated network of signaling pathways via biologically active molecules generated by intestinal microbiota. Some of these molecules could be assembled within nanoparticles known as outer membrane vesicles (OMVs). Recent studies propose that OMVs play a critical role in shaping immune responses, including homeostasis and acute inflammatory responses. Moreover, these OMVs have an immense capacity to be applied in medical research, such as OMV-based vaccines and drug delivery. This review presents a comprehensive overview of emerging knowledge about biogenesis, the role, and application of these bacterial-derived OMVs, including OMV-based vaccines, OMV adjuvants characteristics, OMV vehicles (in conjugated vaccines), cancer immunotherapy, and drug carriers and delivery systems. Moreover, we also highlight the significance of the potential role of these OMVs in diagnosis and therapy.

The role of extracellular vesicles in periodontitis: pathogenesis, diagnosis, and therapy

Periodontitis is a prevalent disease and one of the leading causes of tooth loss. Biofilms are initiating factor of periodontitis, which can destroy periodontal tissue by producing virulence factors. The overactivated host immune response is the primary cause of periodontitis. The clinical examination of periodontal tissues and the patient's medical history are the mainstays of periodontitis diagnosis. However, there is a lack of molecular biomarkers that can be used to identify and predict periodontitis activity precisely. Non-surgical and surgical treatments are currently available for periodontitis, although both have drawbacks. In clinical practice, achieving the ideal therapeutic effect remains a challenge. Studies have revealed that bacteria produce extracellular vesicles (EVs) to export virulence proteins to host cells. Meanwhile, periodontal tissue cells and immune cells produce EVs that have pro- or anti-inflammatory effects. Accordingly, EVs play a critical role in the pathogenesis of periodontitis. Recent studies have also presented that the content and composition of EVs in saliva and gingival crevicular fluid (GCF) can serve as possible periodontitis diagnostic indicators. In addition, studies have indicated that stem cell EVs may encourage periodontal regeneration. In this article, we mainly review the role of EVs in the pathogenesis of periodontitis and discuss their diagnostic and therapeutic potential.

Saliva Diagnosis Using Small Extracellular Vesicles and Salivaomics

Saliva is a complex oral biofluid composed of various biological molecules secreted by major and minor salivary glands, as well as by-products of host oral cells, oral bacteria, small extracellular vesicles (sEVs), and gingival crevicular fluid. Recently, salivary small extracellular vesicles and salivary multi-omics (microbiome, transcriptome, DNA methylome and proteome) are emerging as potential diagnostic tools for oral diseases, including the highly prevalent periodontitis. Here, we describe the methodologies for how to isolate salivary sEVs using the size exclusion chromatography method, and how to perform salivaomics, which may guide future dental research.

Production and purification of bacterial membrane vesicles for biotechnology applications: Challenges and opportunities

Bacterial membrane vesicles (BMVs) are bi-layered nanostructures derived from Gram-negative and Gram-positive bacteria. Among other pathophysiological roles, BMVs are critical messengers in intercellular communication. As a result, BMVs are emerging as a promising technology for the development of numerous therapeutic applications. Despite the remarkable progress in unveiling BMV biology and functions in recent years, their successful isolation and purification have been limited. Several challenges related to vesicle purity, yield, and scalability severely hamper the further development of BMVs for biotechnology and clinical applications. This review focuses on the current technologies and methodologies used in BMV production and purification, such as ultracentrifugation, density-gradient centrifugation, size-exclusion chromatography, ultrafiltration, and precipitation. We also discuss the current challenges related to BMV isolation, large-scale production, storage, and stability that limit their application. More importantly, the present work explains the most recent strategies proposed for overcoming those challenges. Finally, we summarize the ongoing applications of BMVs in the biotechnological field.

Epigenetics in susceptibility, progression, and diagnosis of periodontitis

Periodontitis is characterized by irreversible destruction of periodontal tissue. At present, the accepted etiology of periodontitis is based on a three-factor theory including pathogenic bacteria, host factors, and acquired factors. Periodontitis development usually takes a decade or longer and is therefore called chronic periodontitis (CP). To search for genetic factors associated with CP, several genome-wide association study (GWAS) analyses were conducted; however, polymorphisms associated with CP have not been identified. Epigenetics, on the other hand, involves acquired transcriptional regulatory mechanisms due to reversibly altered chromatin accessibility. Epigenetic status is a condition specific to each tissue and cell, mostly determined by the responses of host cells to stimulations by local factors, like bacterial inflammation, and systemic factors such as nutrition status, metabolic diseases, and health conditions. Significantly, epigenetic status has been linked with the onset and progression of several acquired diseases. Thus, epigenetic factors in periodontal tissues are attractive targets for periodontitis diagnosis and treatments. In this review, we introduce accumulating evidence to reveal the epigenetic background effects related to periodontitis caused by genetic factors, systemic diseases, and local environmental factors, such as smoking, and clarify the underlying mechanisms by which epigenetic alteration influences the susceptibility of periodontitis.

The Relevance of DNA Methylation and Histone Modification in Periodontitis: A Scoping Review

Background: Periodontitis is a chronic inflammatory disease involving an interplay between bacteria, inflammation, host response genes, and environmental factors. The manifestation of epigenetic factors during periodontitis pathogenesis and periodontal inflammation is still not well understood, with limited reviews on histone modification with periodontitis management. This scoping review aims to evaluate current evidence of global and specific DNA methylation and histone modification in periodontitis and discuss the gaps and implications for future research and clinical practice. Methods: A scoping literature search of three electronic databases was performed in SCOPUS, MEDLINE (PubMed) and EMBASE. As epigenetics in periodontitis is an emerging research field, a scoping review was conducted to identify the extent of studies available and describe the overall context and applicability of these results. Results: Overall, 30 studies were evaluated, and the findings confirmed that epigenetic changes in periodontitis comprise specific modifications to DNA methylation patterns and histone proteins modification, which can either dampen or promote the inflammatory response to bacterial challenge. Conclusions: The plasticity of epigenetic modifications has implications for the future development of targeted epi-drugs and diagnostic tools in periodontitis. Such advances could be invaluable for the early detection and monitoring of susceptible individuals.

Simulated and clinical aerosol spread in common periodontal aerosol-generating procedures

Objectives

This study evaluated particle spread associated with various common periodontal aerosol-generating procedures (AGPs) in simulated and clinical settings.

Materials and methods

A simulation study visualized the aerosols, droplets, and splatter spread with and without high-volume suction (HVS, 325 L/min) during common dental AGPs, namely ultrasonic scaling, air flow prophylaxis, and implant drilling after fluorescein dye was added to the water irrigant as a tracer. Each procedure was repeated 10 times. A complementary clinical study measured the spread of contaminated particles within the dental operatory and quantified airborne protein dispersion following 10 min of ultrasonic supragingival scaling of 19 participants during routine periodontal treatment.

Results

The simulation study data showed that air flow produced the highest amount of splatters and the ultrasonic scaler generated the most aerosol and droplet particles at 1.2 m away from the source. The use of HVS effectively reduced 37.5–96% of splatter generation for all three dental AGPs, as well as 82–93% of aerosol and droplet particles at 1.2 m for the ultrasonic scaler and air polisher. In the clinical study, higher protein levels above background levels following ultrasonic supragingival scaling were detected in fewer than 20% of patients, indicating minimal particle spread.

Conclusions

While three common periodontal AGPs produce aerosols and droplet particles up to at least 1.2 m from the source, the use of HVS is of significant benefit. Routine ultrasonic supragingival scaling produced few detectable traces of salivary protein at various sites throughout the 10-min dental operatory.

Clinical relevance

The likelihood of aerosol spread to distant sites during common periodontal AGPs is greatly reduced by high-volume suction. Clinically, limited evidence of protein contaminants was found following routine ultrasonic scaling, suggesting that the the majority of the contamination consisits of the irrigant rather than organic matter from the oral cavity.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00784-022-04532-8.

Commensal and Pathogenic Bacterial-Derived Extracellular Vesicles in Host-Bacterial and Interbacterial Dialogues: Two Sides of the Same Coin

Extracellular vesicles (EVs) cause effective changes in various domains of life. These bioactive structures are essential to the bidirectional organ communication. Recently, increasing research attention has been paid to EVs derived from commensal and pathogenic bacteria in their potential role to affect human disease risk for cancers and a variety of metabolic, gastrointestinal, psychiatric, and mental disorders. The present review presents an overview of both the protective and harmful roles of commensal and pathogenic bacteria-derived EVs in host-bacterial and interbacterial interactions. Bacterial EVs could impact upon human health by regulating microbiota–host crosstalk intestinal homeostasis, even in distal organs. The importance of vesicles derived from bacteria has been also evaluated regarding epigenetic modifications and applications. Generally, the evaluation of bacterial EVs is important towards finding efficient strategies for the prevention and treatment of various human diseases and maintaining metabolic homeostasis.

Salivary Exosomes: From Waste to Promising Periodontitis Treatment

Periodontitis is a chronic inflammatory condition that causes tooth loss by destroying the supporting components of the teeth. In most cases, it is difficult to diagnose early and results in severe phases of the disease. Given their endogenous origins, exosomes, which are rich in peptides, lipids, and nucleic acids, have emerged as a cell-free therapeutic approach with low immunogenicity and increased safety. Because the constituents of exosomes can be reprogrammed depending on disease states, exosomes are increasingly being evaluated to act as potential diagnostic biomarkers for dental disease, including periodontitis. Exosomes also have been demonstrated to be involved in inflammatory signal transmission and periodontitis progression in vitro, indicating that they could be used as therapeutic targets for periodontal regeneration. Nevertheless, a review on the involvement of salivary exosomes in periodontitis in impacting the successful diagnosis and treatment of periodontitis is still lacking in the literature. Thus, this review is intended to scrutinize recent advancements of salivary exosomes in periodontitis treatment. We summarize recent research reports on the emerging roles and characteristics of salivary exosomes, emphasizing the different expressions and changed biological roles of exosomes in periodontitis.

Salivary SARS-CoV-2 antibody detection using S1-RBD protein-immobilized 3D melt electrowritten poly(ε-caprolactone) scaffolds

Sensitive detection of immunoglobulin antibodies against SARS-CoV-2 during the COVID-19 pandemic is critical to monitor the adaptive immune response after BNT162b2 mRNA vaccination. Currently employed binding antibody detection tests using 2D microplate-based enzyme-linked immunosorbent assays (ELISA) are limited by the degree of sensitivity. In this study, a 3D antibody test was developed by immobilizing the receptor-binding domain on Spike subunit 1 (S1-RBD) of SARS-CoV-2 onto engineered melt electrowritten (MEW) poly(ε-caprolactone) (PCL) scaffolds (pore: 500 μm, fiber diameter: 17 μm) using carbodiimide crosslinker chemistry. Protein immobilization was confirmed using X-ray photoelectron spectroscopy (XPS) by the presence of peaks corresponding with nitrogen. Self-developed indirect ELISA was performed to assess the functionality of the 3D platform in comparison with a standard 2D tissue culture plate (TCP) system, using whole unstimulated saliva samples from 14 non-vaccinated and 20 vaccinated participants (1- and 3- weeks post-dose 1; 3 days, 1 week and 3 weeks post-dose 2) without prior SARS-CoV-2 infection. The three-dimensional S1-RBD PCL scaffolds, while demonstrating a kinetic trend comparable to 2D TCP, exhibited significantly higher sensitivity and detection levels for all three immunoglobulins assayed (IgG, IgM, and IgA). These novel findings highlight the potential of MEW PCL constructs in the development of improved low-cost, point-of-care, and self-assessing diagnostic platforms for the detection and monitoring of SARS-CoV-2 antibodies.

Our work developed a 3D SARS-CoV-2 antibody detection platform in non-invasive saliva samples using S1-RBD protein-immobilized 3D melt electrowritten poly(ε-caprolactone) scaffolds.

Iron accumulation is associated with periodontal destruction in a mouse model of HFE-related haemochromatosis

OBJECTIVE

To investigate the effect of Hfe gene mutation on the distribution of iron and periodontal bone loss in periodontal tissues.

BACKGROUND DATA

It remains unclear how tissue iron loading affects the periodontium architectures in a genetic animal model of hereditary haemochromatosis (HH).

METHODS

Male C57BL/6 Hfe^-/- (8 weeks old) and wild-type (WT) mice were utilized to examine the iron distribution in periodontal tissues, as well as periodontal tissues changes using micro-computed tomography and histomorphometric analysis. Furthermore, tissue inflammatory mediators, bone markers and periodontal pathogens were carried out in PFA-fixed paraffin-embedded tissues using ELISA, RT-qPCR and genomic DNA qPCR, respectively.

RESULTS

Excessive iron deposition was found in the periodontal ligament, gingiva and alveolar bone in Hfe^-/- mice relative to their WT counterparts. This, in turn, was associated with significant periodontal bone loss, increased cemento-enamel junction-alveolar bone crest distance and decreased expression of molecules involved in bone development and turnover. Furthermore, the pro-inflammatory cytokine - interleukin 6 and periodontal bacteria - Campylobacter rectus were significantly increased in Hfe^-/- mice compared with WT controls.

CONCLUSION

Our results suggest that the iron loading in a mouse model of HH decreases alveolar bone formation and leads to alterations in the inflammatory state in the periodontium. Periodontal health should be assessed during the clinical assessment of HFE-HH patients.

The emerging role of small extracellular vesicles in saliva and gingival crevicular fluid as diagnostics for periodontitis

Periodontitis is a highly prevalent multifactorial chronic inflammatory disease associated with a destructive host immune-inflammatory response to microbial dysbiosis. Current clinical diagnosis is reliant on measuring past periodontal tissue loss, with a lack of molecular biomarkers to accurately diagnose periodontitis activity in 'real-time'. Thus, discovery of new classes of diagnostic biomarkers is of critical importance in periodontology. Small extracellular vesicles (<200 nm in diameter; sEVs) from oral biofluids (saliva and gingival crevicular fluid-GCF) are lipid-encapsulated bilayered vesicles and have recently emerged as a potential source of biomarkers for periodontal disease (gingivitis and periodontitis), due to the cargo of protein, genetic material and lipids derived from their parent cells. There is limited information on the isolation and characterisation methods of saliva/GCF-sEVs or the characterisation of sEVs cargo as biomarkers for periodontitis. In this review, we detail the composition of sEVs and summarise their isolation and characterisation from saliva and GCF. The potential role of saliva and GCF-derived sEVs in periodontitis diagnosis is also explored. It is proposed that sEVs cargo, including protein, microRNA, message RNA and DNA methylation, are potential biomarkers for periodontitis with good diagnostic power (area under the curve-AUC > 0.9).

The Mechanosensing and Global DNA Methylation of Human Osteoblasts on MEW Fibers

Cells interact with 3D fibrous platform topography via a nano-scaled focal adhesion complex, and more research is required on how osteoblasts sense and respond to random and aligned fibers through nano-sized focal adhesions and their downstream events. The present study assessed human primary osteoblast cells’ sensing and response to random and aligned medical-grade polycaprolactone (PCL) fibrous 3D scaffolds fabricated via the melt electrowriting (MEW) technique. Cells cultured on a tissue culture plate (TCP) were used as 2D controls. Compared to 2D TCP, 3D MEW fibrous substrates led to immature vinculin focal adhesion formation and significantly reduced nuclear localization of the mechanosensor-yes-associated protein (YAP). Notably, aligned MEW fibers induced elongated cell and nucleus shape and highly activated global DNA methylation of 5-methylcytosine, 5-hydroxymethylcytosine, and N-6 methylated deoxyadenosine compared to the random fibers. Furthermore, although osteogenic markers (osterix-OSX and bone sialoprotein-BSP) were significantly enhanced in PCL-R and PCL-A groups at seven days post-osteogenic differentiation, calcium deposits on all seeded samples did not show a difference after normalizing for DNA content after three weeks of osteogenic induction. Overall, our study linked 3D extracellular fiber alignment to nano-focal adhesion complex, nuclear mechanosensing, DNA epigenetics at an early point (24 h), and longer-term changes in osteoblast osteogenic differentiation.

Uncovering the Oral Dysbiotic Microbiota as Masters of Neutrophil Responses in the Pathobiology of Periodontitis

Numerous bacterial species participate in the shift of the oral microbiome from beneficial to dysbiotic. The biggest challenge lying ahead of microbiologists, immunologists and dentists is the fact that the bacterial species act differently, although usually synergistically, on the host immune cells, including neutrophils, and on the surrounding tissues, making the investigation of single factors challenging. As biofilm is a complex community, the members interact with each other, which can be a key issue in future studies designed to develop effective treatments. To understand how a patient gets to the stage of the late-onset (previously termed chronic) periodontitis or develops other, in some cases life-threatening, diseases, it is crucial to identify the microbial composition of the biofilm and the mechanisms behind its pathogenicity. The members of the red complex (Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia) have long been associated as the cause of periodontitis and stayed in the focus of research. However, novel techniques, such as 16S clonal analysis, demonstrated that the oral microbiome diversity is greater than ever expected and it opened a new era in periodontal research. This review aims to summarize the current knowledge concerning bacterial participation beyond P. gingivalis and the red complex in periodontal inflammation mediated by neutrophils and to spread awareness about the associated diseases and pathological conditions.

Characteristics and Clinical Application of Extracellular Vesicle-Derived DNA

Extracellular vesicles (EVs) carry RNA, proteins, lipids, and diverse biomolecules for intercellular communication. Recent studies have reported that EVs contain double-stranded DNA (dsDNA) and oncogenic mutant DNA. The advantage of EV-derived DNA (EV DNA) over cell-free DNA (cfDNA) is the stability achieved through the encapsulation in the lipid bilayer of EVs, which protects EV DNA from degradation by external factors. The existence of DNA and its stability make EVs a useful source of biomarkers. However, fundamental research on EV DNA remains limited, and many aspects of EV DNA are poorly understood. This review examines the known characteristics of EV DNA, biogenesis of DNA-containing EVs, methylation, and next-generation sequencing (NGS) analysis using EV DNA for biomarker detection. On the basis of this knowledge, this review explores how EV DNA can be incorporated into diagnosis and prognosis in clinical settings, as well as gene transfer of EV DNA and its therapeutic potential.

The Role and Application of Salivary Exosomes in Malignant Neoplasms

The study of salivary exosomes in malignant neoplasms has attracted widespread attention in the clinical setting. Although a variety of diagnostic and treatment approaches have been proposed, there are some limitations to their application. In recent years, the role of salivary exosomes in cancer has been increasingly studied. Salivary exosomes not only renew and regulate the biological behavior of tumor cells, such as malignant proliferation, migration, and invasion, but they also serve as ideal markers for early diagnosis of diseases and may represent an effective therapeutic target. This article reviews the current research on salivary exosomes in malignant neoplasms.

Periodontal and Dental Pulp Cell-Derived Small Extracellular Vesicles: A Review of the Current Status

Extracellular vesicles (EVs) are membrane-bound lipid particles that are secreted by all cell types and function as cell-to-cell communicators through their cargos of protein, nucleic acid, lipids, and metabolites, which are derived from their parent cells. There is limited information on the isolation and the emerging therapeutic role of periodontal and dental pulp cell-derived small EVs (sEVs, <200 nm, or exosome). In this review, we discuss the biogenesis of three EV subtypes (sEVs, microvesicles and apoptotic bodies) and the emerging role of sEVs from periodontal ligament (stem) cells, gingival fibroblasts (or gingival mesenchymal stem cells) and dental pulp cells, and their therapeutic potential in vitro and in vivo. A review of the relevant methodology found that precipitation-based kits and ultracentrifugation are the two most common methods to isolate periodontal (dental pulp) cell sEVs. Periodontal (and pulp) cell sEVs range in size, from 40 nm to 2 μm, due to a lack of standardized isolation protocols. Nevertheless, our review found that these EVs possess anti-inflammatory, osteo/odontogenic, angiogenic and immunomodulatory functions in vitro and in vivo, via reported EV cargos of EV–miRNAs, EV–circRNAs, EV–mRNAs and EV–lncRNAs. This review highlights the considerable therapeutic potential of periodontal and dental pulp cell-derived sEVs in various regenerative applications.