Diagnostic potential and future directions of biomarkers in gingival crevicular fluid and saliva of periodontal diseases: Review of the current evidence

Biomarkers in Oral Fluids as Diagnostic Tool for Psoriasis

Psoriasis is a prevalent worldwide chronic immuno-inflammatory skin disease with various variants and atypical cases. The use of biomarkers for the diagnosis of psoriasis can favor timely treatment and thus improve the quality of life of those affected. In general, the search for biomarkers in oral fluids is recommended as it is a non-invasive and fast technique. This narrative review aimed to identify biomarkers in gingival crevicular fluid (GCF) and saliva to diagnose psoriasis. To achieve this goal, we selected the available literature using the following MESH terms: “psoriasis”, “saliva” and “gingival crevicular fluid”. The studies analyzed for this review cover original research articles available in English. We found three full articles available for psoriasis biomarkers in GCF and ten articles available for psoriasis biomarkers in saliva. Studies showed that in the saliva of healthy individuals and those with psoriasis, there were differences in the levels of inflammatory cytokines, immunoglobulin A, and antioxidant biomarkers. In GCF, individuals with psoriasis showed higher levels of S100A8, IL-18 and sE-selectin in comparison to healthy individuals, independent of periodontal status. Despite these findings, more studies are required to determine an adequate panel of biomarkers to use in saliva or GCF for psoriasis.

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 Proteomics Identifies Transthyretin as a Biomarker of Early Dementia Conversion

Background:

Alzheimer’s disease (AD) remains to date an incurable disease with a long asymptomatic phase. Early diagnosis in peripheral biofluids has emerged as key for identifying subjects at risk and developing therapeutics and preventative approaches.

Objective:

We apply proteomics discovery to identify salivary diagnostic biomarkers for AD, which are suitable for self-sampling and longitudinal biomonitoring during aging.

Methods:

57 participants were recruited for the study and were categorized into Cognitively normal (CNh) (n = 19), mild cognitive impaired (MCI) (n = 21), and Alzheimer’s disease (AD) (n = 17). On a subset of subjects, 3 CNh and 3 mild AD, shot-gun filter aided sample preparation (FASP) proteomics and liquid chromatography mass spectroscopy (LC-MS/MS) was employed in saliva and cerebrospinal fluid (CSF) to identify neural-derived proteins. The protein level of salivary Transthyretin (TTR) was validated using western blot analysis across groups.

Results:

We found that 19.8% of the proteins in saliva are shared with CSF. When we compared the saliva and CSF proteome, 24 hits were decreased with only one protein expressed more. Among the differentially expressed proteins, TTR with reported function in amyloid misfolding, shows a significant drop in AD samples, confirmed by western blot showing a 0.5-fold reduction in MCI and AD compared to CNh.

Conclusion:

A reduction in salivary TTR appears with the onset of cognitive symptoms. More in general, the proteomic profiling of saliva shows a plethora of biomarkers worth pursuing as non-invasive hallmarks of dementia in the preclinical stage.

Oxidative/anti-oxidative effects of colloidal silver ions and chlorhexidine in saliva and gingival fluid of periodontal patients

Background/Aim. Chronic periodontitis is an inflammatory disease. Oxidative stress is an important factor in periodontitis progress, hence examining the antioxidative properties of antiseptics, such as chlorhexidine (CHX) and silver ions solution (SSI), is a beneficial biomarker in estimating the recovery of tissue impairment during periodontal disease treatment. Methods. This clinical trial was conducted on the control group referred to healthy volunteers and individuals with periodontal disease, divided into two subgroups: before and after applying antiseptic treatments (CHX or SSI). Measurements of oxidative/antioxidative parameters were addressed to determine thiobarbituric acid products (TBARS) concentration and total superoxide dismutase (tSOD) activity in saliva and gingival crevicular fluid (GCF) of periodontal patients. Results. TBARS concentration was increased in saliva before the CHX treatment compared to the periodontal group after the CHX treatment, as well as before both CHX and SSI antiseptic treatment in CGF, compared to controls and periodontal groups after the treatment. Patients before SSI treatment had increased tSOD activity in saliva compared to the control group treated with SSI, as well as compared to patients after the SSI treatment. Additionally, tSOD activity was increased in GCF in patients with periodontitis before antiseptic treatment (CHX, SSI) compared to the control or the group of patients after the appropriate treatment. Conclusion. Our results revealed elevated lipid peroxidation in CGF, which reflected the promotion of oxidative stress during periodontal inflammation. The study suggests that antiseptics with antioxidant properties may reduce tissue damage initiated by periodontal disease. Moreover, the determination of oxidative/antioxidative parameters can be important for diagnosing, monitoring, and prognosis of the clinical state of periodontal patients.

Evaluation of GCF IL-17, IL-10, TWEAK and sclerostin levels after SRP and adjunctive use of diode laser application in periodontitis patients

BACKGROUND

The aim of the present study was to evaluate the clinical efficacy of the diode laser as an adjunct to scaling and root planing (SRP) and also determine the biochemical profile by evaluating the gingival crevicular fluid (GCF) levels of interleukin (IL)-17, IL-10, TNF-related weak inducer of apoptosis (TWEAK) and sclerostin.

METHODS

A total of 40 systemically healthy, stage III periodontitis patients were included in this randomized controlled study. Participants were randomly divided into two groups as scaling root planning (SRP) + diode laser(L) (0.80W power, 940nm wavelength and 0.80J/s energy level) and only SRP group. Recording of periodontal parameters and collecting GCF samples were performed at baseline, 1^st and 3^rd months. Biomarker levels in GCF were measured with ELISA .

RESULTS

At baseline, no significant difference was detected between groups in terms of both clinical and biochemical parameters. All biochemical parameters (except for IL-10 in control group), presented a statistically significant difference for 3 months study period in both groups. When laser and control groups were compared, significant differences were not observed, except the lower GCF IL-17 levels (p = 0.025), bleeding on probing (p = 0.028) and clinical attachment level (CAL) (p = 0.0002) values in laser group at 3^rd , 1^st and 3^rd months, respectively. Statistically significant correlations were also noted between biochemical parameters and clinical parameters.

CONCLUSION

The GCF IL-17, TWEAK and sclerostin levels may be useful for monitoring response to SRP+L therapy. However, long-term studies on higher populations are needed to evaluate the effectiveness of adjunctive use of diode laser application to SRP. This article is protected by copyright. All rights reserved.

Metabolomic Evaluation of Chronic Periodontal Disease in Older Adults

Periodontal disease is an infectious inflammatory disease related to the destruction of supporting tissues of the teeth, leading to a functional loss of the teeth. Inflammatory molecules present in the exudate are catalyzed and form different metabolites that can be identified and quantified. Thus, we evaluated the inflammatory exudate present in crevicular fluid to identify metabolic biological markers for diagnosing chronic periodontal disease in older adults. Research participants were selected from long-term institutions in Brazil. Participants were individuals aged 65 years or older, healthy, or with chronic periodontal disease. Gas chromatography/mass spectrometry was used to evaluate potential biomarkers in 120 crevicular fluid samples. We identified 969 metabolites in the individuals. Of these, 15 metabolites showed a variable importance with projection score > 1 and were associated with periodontal disease. Further analysis showed that among the 15 metabolites, two (5-aminovaleric acid and serine, 3TMS derivative) were found at higher concentrations in the crevicular fluid, indicating their potential diagnostic power for periodontal disease in older adults. Our findings indicated that some metabolites are present at high concentrations in the crevicular fluid in older adults with periodontal disease and can be used as biomarkers of periodontal disease.

Correlations between Salivary Immuno-Biochemical Markers and HbA1c in Type 2 Diabetes Subjects before and after Dental Extraction

Dental extraction can trigger certain sequences of complex processes that involve both hard (alveolar bone) and soft tissue (periodontal ligament, gingiva) remodeling. Type 2 diabetes is a serious risk factor for many oral pathologies, both in terms of progression and severity, but also regarding subsequent rehabilitation possibilities. The aim of this study was to establish whether certain molecules: osteoprotegerin (OPG), kappa B nuclear factor receptor activator ligand (RANKL), hepatocyte growth factor (HGF), tumor necrosis factor-α (TNF-α), interleukin 18 (IL-18), matrix metalloproteinase 9 (MMP-9) and oxidative stress markers-total oxidant status (TOS), total antioxidant capacity (TAC)-evaluated in saliva are modified post-extraction in type 2 diabetes mellitus subjects and whether there is a correlation with HbA1c levels. The aforementioned markers plus HbA1c were investigated in a group of systemically healthy subjects (n = 45) and in a type 2 diabetes mellitus group (n = 41) before and three months after a tooth extraction. Diabetes patients' recorded increased levels of OPG, RANKL, TNF-α, MMP-9, IL-18 and TOS compared to controls both pre- and post-extraction. In both study groups, the average OPG, HGF and TAC level recorded an upward trend three months post-extraction. TNF-α registered a statistically significant decrease only in the diabetes group after dental extraction, together with a decrement of mean HbA1c levels in the diabetes group. By plotting the ROC (receiver operating characteristic) curve, at baseline RANKL, TNF-α, IL-18, MMP-9, TOS and OPG were good predictors of HbA1c levels. Post-extraction, there was a significant correlation between HbA1c and oxidative status biomarkers, however the linear regression model indicated the influence of all studied salivary markers in HbA1c determinism, in a considerable proportion. In conclusion, our study demonstrated that several oxidative status markers and proinflammatory biomarkers are modified in the saliva of diabetic patients and they correlate to HbA1c levels, thus being potential indicators of the post-extraction healing status in the oral cavity.

Childhood Allergy Disease, Early Diagnosis, and the Potential of Salivary Protein Biomarkers

Allergic disease has risen to epidemic proportions since the last decade and is among the most common noncommunicable, chronic diseases in children and adolescents worldwide. Allergic disease usually occurs in early life; thus, early biomarkers of allergic susceptibility are required for preventive measures to high-risk infants which enable early interventions to decrease allergic severity. However, to date, there is no reliable general or specific allergy phenotype detection method that is easy and noninvasive for children. Most reported allergic phenotype detection methods are invasive, such as the skin prick test (SPT), oral food challenge (OFC), and blood test, and many involve not readily accessible biological samples, such as cord blood (CB), maternal blood, or newborn vernix. Saliva is a biological sample that has great potential as a biomarker measurement as it consists of an abundance of biomarkers, such as genetic material and proteins. It is easily accessible, noninvasive, collected via a painless procedure, and an easy bedside screening for real-time measurement of the ongoing human physiological system. All these advantages emphasise saliva as a very promising diagnostic candidate for the detection and monitoring of disease biomarkers, especially in children. Furthermore, protein biomarkers have the advantages as modifiable influencing factors rather than genetic and epigenetic factors that are mostly nonmodifiable factors for allergic disease susceptibility in childhood. Saliva has great potential to replace serum as a biological fluid biomarker in diagnosing clinical allergy. However, to date, saliva is not considered as an established medically acceptable biomarker. This review considers whether the saliva could be suitable biological samples for early detection of allergic risk. Such tools may be used as justification for targeted interventions in early childhood for disease prevention and assisting in reducing morbidity and mortality caused by childhood allergy.

Origin of MMP-8 and Lactoferrin levels from gingival crevicular fluid, salivary glands and whole saliva

Background

Pathologically elevated levels of matrix metalloproteinase-8 (MMP-8) and Lactoferrin in oral fluids have been associated with the presence of gingivitis/periodontitis. This study aimed to assess the origin of MMP-8 and Lactoferrin in periodontitis patients and to identify the degree to which conventional clinical parameters correlate with their presence.

Methods

A total of ten periodontitis and ten healthy patients were included in this study. Whole saliva (stimulated and unstimulated), parotid/sublingual glandular fluid and gingival crevicular fluid from pockets and sulci were tested for MMP-8 and Lactoferrin and protein concentrations were quantified using an ELISA assay. Clinical parameters were checked for potential associations with MMP-8 and Lactoferrin levels.

Results

Periodontal patients presented higher concentrations of MMP-8 and Lactoferrin in pockets than other sources (P = 0.03). Lactoferrin measurement was higher in the parotid compared to sublingual glandular fluid in periodontitis patients (P = 0.03). Increased probing pocket depth was positively correlated with high MMP-8 and Lactoferrin levels.

Conclusions

Periodontal pockets appear to be the major source of active matrix metalloproteinase and Lactoferrin, which also may also enter the oral cavity through the salivary glands. Since clinically healthy sites in periodontitis patients also had elevated biomarker levels, gingival crevicular fluid biomarker testing may be more predictive of future tissue breakdown than conventional clinical parameters.

What are microbiological effects of the adjunctive use of probiotics in the treatment of periodontal diseases? A systematic review

Probiotics have aroused great interest as an adjunctive treatment to periodontal therapy, due to the frequent colonisation by periodontopathogens after therapy. The aim of this systematic review was to analyse in the scientific literature, evidence of the microbiological effects of probiotics as an adjunct to periodontal therapy in the treatment of periodontal diseases (PD). Only randomised controlled trials (RCT), evaluating the microbiological effect of probiotics as an adjunct to periodontal therapy. The authors conducted a search in PubMed/MEDLINE, LILACS, ScienceDirect, Web of Science and Cochrane Library to identify articles published in English until February 2020. The quality of the studies was assessed using the JADAD scale and the risk of bias was assessed according to the Cochrane Collaboration assessment tool. Of the 265 articles potentially relevant to this review, 10 studies were included. The most frequently used probiotic bacteria were those of the genus Lactobacillus spp. and the time of administration of the probiotics was between 14 days to 3 months. Most studies have shown that the adjuvant use of probiotics reduces the total mean counts of gram-negative anaerobic species (Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola and Prevotella intermedia) and gram-negative coccobacillus (Aggregatibacter actinomycetemcomitans) of subgingival plaque samples. Probiotics adjuvant to periodontal therapy reduces periodontopathogenic species in a greater proportion, compared only to periodontal therapy. Especially the Lactobacillus reuteri strain, without combination with other strains, offered a greater reduction in pathogenic bacteria associated with greater destruction of periodontal tissues and deep periodontal pockets. Researchers should perform high-quality RCT, evaluating single strains without combinations, in order to observe the microbiological benefits as adjunctive treatment of PD.

Molecular Screening and Analysis Reveal Novel Oral Site-Specific Locations for the Cariogenic Pathogen Scardovia wiggsiae

Introduction: Scardovia wiggsiae (SW) is a newly identified cariogenic pathogen associated with severe early childhood caries and oral disease. New studies have confirmed the presence of this organism among clinical samples from both pediatric and adult patients. However, the recent discovery of this organism has left researchers with only limited information available regarding the prevalence of this organism—and virtually no information regarding oral site-specific locations. Based upon this lack of information, the overall objective of this study was to perform an oral site-specific analysis of SW prevalence from clinical samples. Methods: Using an approved human subjects protocol, samples (n = 60) from an existing saliva and site-specific biorepository were identified and screened for SW presence using quantitative polymerase chain reaction (qPCR). These data were summarized and subsequently analyzed for correlations with demographic (age, sex, race or ethnicity) or clinical (body mass index or BMI, primary/mixed/permanent dentition, orthodontic brackets) variables. Results: These data revealed that average DNA concentrations from all sample sites (saliva, dorsum of tongue, gingival crevicular fluid (GCF), biofilm of upper buccal molar, and biofilm of lower lingual incisor) ranged between 13.74 and 14.69 μg/μL, with an overall average of 14.30 μg/μL ± 1.12 (standard error or SE). qPCR screening revealed a total of n = 34/60 or 56.7% of patient samples harboring SW. A total of n = 71/170 specific oral sites harbored this organism, with the majority of the SW-positive participant samples harboring SW at more than one oral site, n = 22/34 or 64.7%, including non-traditional sites such as GCF and the dorsum of the tongue. Weak correlations were found between specific SW outcomes in GCF and type of dentition (permanent; R = 0.2444), as well as SW outcomes in saliva with age (R = 0.228) and presence of orthodontic brackets (R = 0.2118). Conclusions: This study may be among the first to provide oral site-specific analysis to reveal the prevalence and location of Scardovia among clinical patient samples. Moreover, these data also provide some of the first evidence to suggest this organism may be present not only in traditional supragingival tooth-associated biofilm sites, but also in non-traditional oral sites including the dorsum of the tongue and the gingival crevice. Based upon these results, these data may represent a significant advance in our understanding of the potential sites and locations that harbor this organism and may help contribute to our understanding of the prevalence, distribution and potential for the development of oral disease among clinic patients.

Effects of non-surgical periodontal therapy on the cytokine profile in gingival crevicular fluid of breast cancer patients with periodontitis undergoing chemotherapy

OBJECTIVE

This study evaluated the effect of non-surgical periodontal therapy (NSPT) on the cytokine profile in gingival crevicular fluid (GCF) in patients with breast cancer and periodontitis.

METHODS

Forty patients were allocated into the periodontitis group (P) (n = 20) and breast cancer with periodontitis group (BC/P) (n = 20). Two days before the removal of infectious foci from the oral cavity and NSPT, as well as periodontal reevaluations, C-reactive protein, neutrophils (10³μL), and platelets (10³μL), were evaluated. The following cytokines in GCF, interleukin (IL)-4, IL-10, IL-2, IL-6, IL-1β, tumor necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ), and transforming growth factor-β (TGF-β) were evaluated by the Luminex assay at baseline, and 45 and 180 days after therapy. Cytokine levels were analyzed for correlations with the clinical parameters: clinical attachment level (CAL), probing depth (PD), bleeding on probing (BOP), and plaque index (PI).

RESULTS

After NSPT, IL-2, TNF-α, and TGF-β were downregulated (p<0.05) in the BC/P. In the P group, INF-γ, IL-2, and TNF-α were downregulated (p<0.05), and TGF-β was increased (p<0.05). At 180 days, IL-6 in GCF was significantly positively correlated with PD and CAL (r=0.45, r=0.56) in the BC/P (p<0.05). In the P group, IL-1β in GCF was positively correlated with PD and CAL (r=0.56, r=0.59) at 45 days (p<0.05).

CONCLUSION

NSPT, before the start of chemotherapy, helps to reduce the inflammatory markers associated with the activity of periodontal disease, favoring a less inflammatory pattern, to avoid the exacerbation of periodontitis.

Top-Down Proteomics of Human Saliva Highlights Anti-inflammatory, Antioxidant, and Antimicrobial Defense Responses in Alzheimer Disease

Alzheimer disease (AD) is the most prevalent neurodegenerative disease in the elderly, characterized by accumulation in the brain of misfolded proteins, inflammation, and oxidative damage leading to neuronal cell death. By considering the viewpoint that AD onset and worsening may be influenced by environmental factors causing infection, oxidative stress, and inflammatory reaction, we investigated the changes of the salivary proteome in a population of patients with respect to that in healthy controls (HCs). Indeed, the possible use of saliva as a diagnostic tool has been explored in several oral and systemic diseases. Moreover, the oral cavity continuously established adaptative and protective processes toward exogenous stimuli. In the present study, qualitative/quantitative variations of 56 salivary proteoforms, including post-translationally modified derivatives, have been analyzed by RP-HPLC-ESI-IT-MS and MS/MS analyses, and immunological methods were applied to validate MS results. The salivary protein profile of AD patients was characterized by significantly higher levels of some multifaceted proteins and peptides that were either specific to the oral cavity or also expressed in other body districts: (i) peptides involved in the homeostasis of the oral cavity; (ii) proteins acting as ROS/RNS scavengers and with a neuroprotective role, such as S100A8, S100A9, and their glutathionylated and nitrosylated proteoforms; cystatin B and glutathionylated and dimeric derivatives; (iii) proteins with antimicrobial activity, such as α-defensins, cystatins A and B, histatin 1, statherin, and thymosin β4, this last with a neuroprotective role at the level of microglia. These results suggested that, in response to injured conditions, Alzheimer patients established defensive mechanisms detectable at the oral level. Data are available via ProteomeXchange with identifier PXD021538.

Monitoring Salivary Levels of Interleukin 1 Beta (IL-1β) and Vascular Endothelial Growth Factor (VEGF) for Two Years of Orthodontic Treatment: A Prospective Pilot Study

Results

A gradual increase in IL-1β and VEGF was observed at alignment, reaching significance at space closure (p = 0.002 and p = 0.025, respectively). At finishing, both IL-1β and VEGF declined, however, without reverting to baseline values (p = 0.172 and p = 0.207, respectively). Bland-Altman analysis showed the agreement between IL-1β and VEGF in terms of a systematic increase, with a higher percentage difference for VEGF.

Conclusions

The salivary levels of both IL-1β and VEGF increased following orthodontic treatment and reached their peaks during the treatment stage of space closure. This novel approach provides a hint on how and when to sample saliva during orthodontic treatment to analyse bone remodelling.

The Chairside Periodontal Diagnostic Toolkit: Past, Present, and Future

Periodontal diseases comprise a group of globally prevalent, chronic oral inflammatory conditions caused by microbial dysbiosis and the host immune response. These diseases specifically affect the tooth-supporting tissues (i.e., the periodontium) but are also known to contribute to systemic inflammation. If left untreated, periodontal diseases can ultimately progress to tooth loss, lead to compromised oral function, and negatively impact the overall quality of life. Therefore, it is important for the clinician to accurately diagnose these diseases both early and accurately chairside. Currently, the staging and grading of periodontal diseases are based on recording medical and dental histories, thorough oral examination, and multiple clinical and radiographic analyses of the periodontium. There have been numerous attempts to improve, automate, and digitize the collection of this information with varied success. Recent studies focused on the subgingival microbiome and the host immune response suggest there is an untapped potential for non-invasive oral sampling to assist clinicians in the chairside diagnosis and, potentially, prognosis. Here, we review the available toolkit available for diagnosing periodontal diseases, discuss commercially available options, and highlight the need for collaborative research initiatives and state-of-the-art technology development across disciplines to overcome the challenges of rapid periodontal disease diagnosis.

The potential impact of salivary peptides in periodontitis

Periodontitis is a complex immune-inflammatory condition characterized by the disruption of the periodontal ligament and subsequent formation of periodontal pockets, and by alveolar bone loss, often resulting in tooth loss. A myriad of factors, namely, genetic, metabolic, immunological, and inflammatory, is associated with progression of periodontitis. Periodontitis is also associated with systemic conditions such as neoplastic disorders, obesity, and diabetes. The current diagnosis of this disease relies on clinical measurements such as clinical attachment loss and probing depth, which have poor precision due to patient, operator and probe-related factors. Thus, there is a need to develop reliable, objective, and reproducible biomarkers for early diagnosis of periodontitis. In this regard, saliva, with contributions from the gingival crevicular fluid, holds great potential. However, most of the information on biomarkers of periodontium-related salivary proteins has come from studies on the molecular pathogenesis of periodontitis. In periodontitis, a more holistic approach, such as the use of -omics technologies, for biomarker discovery, is needed. Herein, we review the biomarkers proposed to date for the assessment of periodontitis, with emphasis on the role of salivary peptides in periodontitis and their assessment by high-throughput saliva proteomics. We also discuss the challenges pertaining to the identification of new periodontitis biomarkers in saliva.

Predictive Periodontitis: The Most Promising Salivary Biomarkers for Early Diagnosis of Periodontitis

The primary cause of tooth loss in the industrialized world is periodontitis, a bacterial anaerobic infection whose pathogenesis is characterized by composite immune response. At present, the diagnose of periodontitis is made by a complete status check of the patient’s periodontal health; full-mouth plaque score, full-mouth bleeding score, probing depth, clinical attachment level, bleeding on probing, recessions, mobility, and migration are evaluated in order to provides a clear picture of the periodontal conditions of a single patient. Chair-side diagnostic tests based on whole saliva could be routinely used by periodontists for a very early diagnosis of periodontitis, monitoring, prognosis, and management of periodontal patients by biomarker detection, whose diagnostic validity is related to sensitivity and specificity. Recent paper reviews and meta-analyses have focused on five promising host derived biomarkers as candidate for early diagnosis of periodontitis: MMP-8 (Metalloproteinase-8), MIP-1α (Macrophage inflammatory protein-1 alpha), IL-1 β (Interleukin-1 beta), IL-6 (Interleukin-6), and HB (Hemoglobin), and their combinations. Chair-side Lab-on-a-chip (LOC) technology may soon become an important part of efforts to detect such biomarkers in saliva medium to improve worldwide periodontal health in developed nations as well as in underserved communities and poor countries. Their applications in preventive and predictive medicine is now fundamental, and is aimed at the early detection of risk factors or the presence or evolution of the disease, and in personalized medicine, which aims to identify tailor-made treatments for individual patients. The aim of the present paper is to be informative about host derived periodontal biomarkers and, in particular, we intend to report information about the most important immune response derived biomarkers and Hemoglobin as candidates to be routinely utilized in order to obtain a chair-side early diagnosis of periodontal disease.

Intra-individual cytokine profile in peri-implantitis and periodontitis: A cross-sectional study

AIM

To study cytokine profiles and intra-individual correlations in crevicular fluid samples at periodontitis, peri-implantitis, and healthy sites.

MATERIALS AND METHODS

Samples from gingival crevicular fluid (GCF) and peri-implant crevicular fluid (PICF) were collected from healthy and diseased sites in patients who had had dental implants for a minimum of 10 years. Cytokine levels were analyzed using the Bio-Plex Pro Human inflammation kit, which included biomarkers for the tumor necrosis factor-α (TNF-α) superfamily, regulatory T Cell (Treg) cytokines, and interferon (IFN) proteins.

RESULTS

Gingival crevicular fluid/PICF cytokine levels, determined in samples from 163 patients, were frequently lower for healthy tooth and implant sites compared to sites with periodontitis or peri-implantitis. In contrast, there were no significant differences in cytokine levels between peri-implant sites and periodontitis sites. Intra-individual correlations between cytokines at peri-implant sites were frequently significant. In addition, the cytokines IFN-λ1 and TNFSF12 were significantly correlated with the presence of peri-implantitis.

CONCLUSION

Within the limits of this study, the intra-individual cytokine profile did not differ between sites diagnosed with periodontitis and those diagnosed with peri-implantitis, but did differ between healthy tooth and healthy implant sites. Studying intra-individual cytokine profiles is a method to elucidate possible differences between the etiopathogeneses of periodontitis and peri-implantitis, since it is well known that immune responses to dysbiosis vary between individuals according to host factors. Thus, the findings of the present study are potentially relevant to the advancement of knowledge in this field.

Gingival Crevicular Fluid (GCF): A Diagnostic Tool for the Detection of Periodontal Health and Diseases

The methodologies applicable for the evaluation of periodontal associated diseases are constantly evolving to provide quick, realistic, and scientifically proven results. Trends in the past followed a clinical evaluation of periodontal tissues and radiographic-based reports that formed the foundation for detection of diseases involving the structures supporting the teeth. As the confines and limitations of conventional strategies became obvious over the passage of time, hand in hand variety of techniques have evolved and experimentally justified. These improvisations are based on an improved understanding of the periodontal-pathogenic cascade. Periodontal pathogenesis and a paradigm shift from disease understanding to disease prevention and treatment entail few prerequisites that demand the objectivity of diagnostics procedure that includes sensitivity and specificity along with an explanation of the intensity of the disease, Gingival crevicular fluid an oral bio-fluid resides in the close proximity with gingival tissues have been widely used to understand and differentiate the periodontal health and diseased status. The biomarkers present in the GCF can be a reliable tool to detect the minute changes seen in the disease processes. The GCF consists of various host and bacterial-derived products as well as biomarkers which in turn can be evaluated for the diagnosis, prognosis as well as management of the periodontal disease. Thus, the review aims at describing GCF as a potential oral biofluid helpful in differentiating periodontal health and disease status.

Polyamine biomarkers as indicators of human disease

The significant increase of periodontitis, chronic kidney disease (CKD), Alzheimer's disease and cancer can be attributed to an ageing population. Each disease produces a range of biomarkers that can be indicative of disease onset and progression. Biomarkers are defined as cellular (intra/extracellular components and whole cells), biochemical (metabolites, ions and toxins) or molecular (nucleic acids, proteins and lipids) alterations which are measurable in biological media such as human tissues, cells or fluids. An interesting group of biomarkers that merit further investigation are the polyamines. Polyamines are a group of molecules consisting of cadaverine, putrescine, spermine and spermidine and have been implicated in the development of a range of systemic diseases, in part due to their production in periodontitis. Cadaverine and putrescine within the periodontal environment have demonstrated cell signalling interfering abilities, by way of leukocyte migration disruption. The polyamines spermine and spermidine in tumour cells have been shown to inhibit cellular apoptosis, effectively prolonging tumorigenesis and continuation of cancer within the host. Polyamine degradation products such as acrolein have been shown to exacerbate renal damage in CKD patients. Thus, the use of such molecules has merit to be utilized in the early indication of such diseases in patients.

Evaluation of active matrix metalloproteinase-8 (aMMP-8) chair-side test as a diagnostic biomarker in the staging of periodontal diseases

OBJECTIVE

There is a need for a reliable complementary diagnostic tool that ideally helps to screen, differentiate sites, activities of and predict future periodontal tissue destruction. The purpose of this cross-sectional study was to investigate the screening and prevention potential of the chair-side/point-of-care (PoC) diagnostic test of salivary active matrix metalloproteinase-8 (aMMP-8) levels at different stages of periodontal disease and periodontal health.

MATERIAL & METHODS

80 individuals were included in this study; 18 with periodontitis stage 3 (P-Stage III), 19 with periodontitis stage-4 (P-Stage IV), 21 with gingivitis, and 22 with clinically healthy periodontium (H). The aMMP-8 levels in GCF and saliva were analyzed by chairside point-of-care aMMP-8 lateral flow immunotest and also by a time-resolved immunofluorescence assay (IFMA).

RESULTS

The sensitivity of the chair-side/PoC test was 83.9 % while specificity was 79.2 %. The aMMP-8 IFMA levels in GCF were significantly higher in P-Stage IV group than P-Stage III, gingivitis and healthy groups (p = 0.01, p = 0.001, p = 0.00, respectively). Moreover, P-Stage III and gingivitis groups had significantly higher aMMP-8 IFMA levels than the healthy group (p < 0.05).

CONCLUSION

The aMMP-8 chair-side test showed promising results in its ability to recognize and predict the inflammatory status even at the very initial/early stages. aMMP-8 chair-side test could be a valuable adjunctive diagnostic and preventive tool to conventional clinical methods in detecting periodontal disease.

Active matrix metalloproteinase-8 and interleukin-6 detect periodontal degeneration caused by radiotherapy of head and neck cancer: a pilot study

Background: This cohort study investigated the role of the active matrix metalloproteinase-8 (aMMP-8) and interleukin-6 (IL-6) as oral fluid biomarkers for monitoring the periodontal degeneration occurring in head and neck cancer (HNC) patients treated by radiotherapy. Research design and methods: Eleven patients, aged 28-74, diagnosed with HNC were included in the study. Complete periodontal and oral examinations were performed pre-radiotherapy and 1 month after radiotherapy. Mouthrinse samples (pre-radiotherapy, after 6 weeks of radiotherapy and 1 month after radiotherapy) were assayed by aMMP-8 point-of-care-kit (PerioSafe®/ORALyzer®) for aMMP-8 and ELISA for IL-6. Results: HNC radiotherapy had a deteriorating impact on the periodontium and a significant impact on periodontal biomarkers aMMP-8 and IL-6 and increased their levels in mouthrinse. Clinical-attachment-loss (CAL) (site of greatest loss: mean = 1.7 mm, range = 1-3 mm) corresponding to rapid progression of periodontitis. There was a positive repeated measures correlation (rmcorr = 0.667) between the aMMP-8 and IL-6 levels. Conclusions: Elevated aMMP-8 levels were observed 1 month after radiotherapy among some HNC patients suggesting a prolonged increased susceptibility to further periodontal tissue destruction. Currently available aMMP-8 point-of-care testing could be useful to monitor and assess quantitatively online and real-time the risk of deterioration of periodontal health during HNC radiotherapy.

Biomarkers associated with periodontitis and peri-implantitis: a systematic review

Purpose

The pathology of peri-implantitis is still not fully understood and there have been recent challenges to the consensus on its aetiology and pathology, especially in comparison with periodontitis. The assessment of biomarkers allows a comparison of the pathology of these diseases. The aim of this systematic review was to answer the research question: “Is there a difference in the biomarkers associated with peri-implantitis compared with periodontitis in adult humans?”

Methods

Electronic databases were searched and screened, and a manual search was also undertaken. The inclusion criteria were adults with peri-implantitis who had been compared to adults with periodontitis with the outcome of biomarkers assessed via biopsies or crevicular fluid samples in primary or secondary care settings, as recorded in case-control, case series and retrospective, prospective and cross-sectional observational studies. Two reviewers independently screened titles and abstracts and assessed full text articles for eligibility and inclusion. Both reviewers independently extracted data and assessed risk of bias. Differences in biomarker levels were the primary outcome and a narrative review was undertaken due to the heterogeneity of studies.

Results

In total, 2,374 articles were identified in the search, of which 111 full-text articles were assessed for eligibility and 13 were included in the qualitative synthesis. Five of the 13 included studies were deemed to be at high risk of bias, with the others having moderate risk. All studies were cross-sectional and performed at university hospitals. Nine of the 13 included studies found significant differences in the levels of biomarkers or their ratios between peri-implantitis and periodontitis. Four of the studies found no significant differences.

Conclusions

Within the limitations of the included studies, it appears that there may be a difference in biomarker levels and ratios between peri-implantitis and periodontitis, suggesting that these disease processes are somewhat distinct.

Gingival Crevicular Fluid Cytokines in Moderate and Deep Sites of Stage III Periodontitis Patients in Different Rates of Clinical Progression

Clinical criteria are inappropriate to measure the degree of susceptibility to progression of periodontal damage. Thus, the aim of this study was to assess whether gingival crevicular fluid (GCF) levels of cytokines could discriminate patients suffering from stage III periodontitis with moderate (Grade B) and rapid rates of progression (Grade C) prior to and 6 months after non-surgical periodontal treatment. GCF samples were obtained from moderate and deep sites of 20 patients diagnosed as Grade B and 20 patients as grade C stage III periodontitis and analyzed for interleukin (IL)-1β, IL-9, tumor necrosis factor (TNF)-α, and vascular endothelial growth factor (VEGF) using a high-sensitivity Bio-Plex Suspension Array System. At baseline, higher IL-1β but lower IL-9 GCF levels were observed in moderate sites of the grade C compared to the grade B group. In spite of comparable clinical improvement, this difference maintained after treatment, suggesting a residual pro-inflammatory state. In deep sites, no differences were observed between periodontitis groups except for VEGF levels that decreased more in Grade B periodontitis at 6 months post-therapy. A mathematical model was constructed to identify Grade C periodontitis patients based on the subjects’ GCF levels of IL-1β and IL-9, which achieved an area under the receiver-operating characteristic (ROC) curve of 0.94. This study can contribute to the early assessment of risk of future breakdown in periodontitis patients.

Evaluation of serum and gingival crevicular fluid microRNA-223, microRNA-203 and microRNA-200b expression in chronic periodontitis patients with and without diabetes type 2

microRNA dysregulation is a reported feature of multiple pathologies, including periodontal disease, as demonstrated on cell lines, in animal models, and tissues biopsies, but serum and gingival crevicular fluid microRNA expression data in humans is scarce, especially with the diabetes (type 2) systemic complication.

OBJECTIVE

To assess serum and gingival crevicular fluid relative quantification levels of miR-223, miR-203, and miR-200b in chronic periodontitis and type 2 diabetic chronic periodontitis patients to address their possible implication in chronic periodontitis pathogenesis and its systemic complications and also to correlate their differential expression with some inflammatory (serum tumor necrosis factor-α and interleukin-10) parameters.

METHODS

Sixty subjects were recruited and divided into three groups; chronic periodontitis (n = 20), type 2 diabetic chronic periodontitis (n = 20), and healthy control (n = 20). Both serum and gingival crevicular fluid were collected from each participant for miRNA expression analysis and serum inflammatory parameters assessment.

RESULTS

A significant increase in the relative quantification levels of miR-223 and miR-200b were detected in patient groups along with a positive correlation with tumor necrosis factor-α. However, miR-203 was significantly decreased in patient groups associated with a negative correlation with tumor necrosis factor-α.

CONCLUSIONS

miR-223 and miR-200b have a potential role in chronic periodontitis pathogenesis associated with type 2 diabetes, with the ability to induce tumor necrosis factor-α secretion, while miR-203 might have a protective and healing role due to the negative correlation with the serum tumor necrosis factor-α levels found. Therefore, they may be considered as a promising therapeutic target and effective serum disease biomarkers.

Label-free quantitative proteomic analysis of gingival crevicular fluid to identify potential early markers for root resorption

Background

Orthodontically-induced root resorption is an iatrogenic effect and it cannot be examined regularly due to the harmful effects of sequential doses of radiation with more frequent radiography. This study aims to compare protein abundance (PA) of pre-treatment and during orthodontic treatment for root resorption and to determine potential early markers for root resorption.

Methods

Ten subjects (n = 10) who had upper and lower fixed appliances (MBT, 3 M Unitek, 0.022″ × 0.028″) were recruited for this study. Human gingival crevicular fluid (GCF) was obtained using periopaper strips at pre-treatment (T0), 1 month (T1), 3 months (T3), and 6 months (T6) of orthodontic treatment. Periapical radiographs of the upper permanent central incisors were taken at T0 and T6 to measure the amount of root resorption. Identification of changes in PA was performed using liquid chromatography-tandem mass spectrometry. Student’s t-test was then performed to determine the significance of the differences in protein abundance before and after orthodontic treatment.

Results

Our findings showed that all ten subjects had mild root resorption, with an average resorption length of 0.56 ± 0.30 mm. A total of 186 proteins were found to be commonly present at T0, T1, T3, and T6. There were significant changes in the abundance of 16 proteins (student’s t-test, p ≤ 0.05). The increased PA of S100A9, immunoglobulin J chain, heat shock protein 1A, immunoglobulin heavy variable 4–34 and vitronectin at T1 suggested a response to stress that involved inflammation during the early phase of orthodontic treatment. On the other hand, the increased PA of thymidine phosphorylase at T3 suggested growth promotion and, angiogenic and chemotactic activities.

Conclusions

The identified proteins can be potential early markers for root resorption based on the increase in their respective PA and predicted roles during the early phase of orthodontic treatment. Non-invasive detection of root resorption using protein markers as early as possible is extremely important as it can aid orthodontists in successful orthodontic treatment.

Biochemical analysis of oral fluids for disease detection

The field of diagnostics using invasive blood testing represents the majority of diagnostic tests used as part of routine health monitoring. The relatively recent introduction of salivary diagnostics has lead to a major paradigm shift in diagnostic analyses. Additionally, in this era of big data, oral fluid testing has shown promising outcomes in a number of fields, particularly the areas of genomics, microbiomics, proteomics, metabolomics, and transcriptomics. Despite the analytical challenges involved in the interpretation of large datasets generated from biochemical studies involving bodily fluids, including saliva, many studies have identified novel oral biomarkers for diagnosing oral and systemic diseases. In this regard, oral biofluids, including saliva, gingival crevicular fluid (GCF), peri-implant crevicular fluid (PICF), dentinal tubular fluid (DTF), are now attracting increasing attention due to their important attributes, such as noninvasive sampling, easy handling, low cost, and more accurate diagnosis of oral diseases. Recently, the utilization of salivary diagnostics to evaluate systemic diseases and monitor general health has increased in popularity among clinicians. Saliva contains a wide range of protein, DNA and RNA biomarkers, which assist in the diagnosis of multiple diseases and conditions, including cancer, cardiovascular diseases (CVD), auto-immune and degenerative diseases, respiratory infections, oral diseases, and microbial (viral, bacterial and fungal) diseases. Moreover, due to its noninvasive nature and ease-of-adoption by children, it is now being used in mass screening programs, oral health-related studies and clinical trials in support of the development of therapeutic agents. The recent advent of highly sensitive technologies, such as next-generation sequencing, mass spectrometry, highly sensitives ELISAs, and homogeneous immunoassays, suggests that even small quantities of salivary biomarkers are able to be assayed accurately, providing opportunities for the development of many future diagnostic applications (including emerging technologies, such as point-of-care and rapid molecular technologies). The present article explores the omics and biochemical compositions of various oral biofluids with important value in diagnostics and monitoring.

Emerging role of exosomes in craniofacial and dental applications

Exosomes, a specific subgroup of extracellular vesicles that are secreted by cells, have been recognized as important mediators of intercellular communication. They participate in a diverse range of physiological and pathological processes. Given the capability of exosomes to carry molecular cargos and transfer bioactive components, exosome-based disease diagnosis and therapeutics have been extensively studied over the past few decades. Herein, we highlight the emerging applications of exosomes as biomarkers and therapeutic agents in the craniofacial and dental field. Moreover, we discuss the current challenges and future perspectives of exosomes in clinical applications.

[Hypoxia-dependent transcriptional control of activity of destructive inflammatory and malignant periodontium changes]

The aim of the study was to evaluate the diagnostic value of determining the level of hypoxia-inducible factor-1α (HIF-1α) in the gingival fluid in patients with chronic generalized periodontitis (CGP) and exacerbation of inflammatory periodontal diseases in patients with cancer of the oral mucosa (OM). A clinical study was carried out with the participation of 60 patients with CGP (group 1) and 22 patients with cancer of OM (group 2) of the T1-2N0M0 stage, as well as 15 healthy individuals with no revealed periodontal pathology. CGP patients, depending on the depth of periodontal pockets (PC), were divided into two subgroups - with a mild degree (PC depth up to 3.5 mm) and an average degree (PC depth from 4 to 6 mm). Group 2 patients were also divided into two subgroups - with exacerbation of CGP (n=12) and patients with no complications (n=10). The content of HIF-1α in the gingival fluid was determined by enzyme immunoassay. The results of the study made it possible to establish that in patients of group 1, the concentration of HIF-1α in inflammatory exudate increased by 2.4 times (p<0.001) compared with the control group. The concentration of HIF-1α in the contents of periodontal pockets in patients with CGP depended on the severity of the disease: with mild CGP, it did not differ from the control group, and with moderate CGP it was 3.15 times higher (p<0.001). In patients with cancer of OM, the concentration of HIF-1α in the gingival fluid did not depend on the presence of inflammatory periodontal lesions and was determined by a multiple increase in the biomarker level (7.5 times) due to the development of a malignant process in the oral cavity. Therefore, monitoring the concentration of HIF-1α in the gingival fluid is informative in patients with CGP in assessing the severity of periodontal conditions, as well as in differential diagnosis with malignant formations of the oral cavity.

Interleukin-1α and -1β assessment in the gingival crevicular fluid of periodontal patients with chronic hepatitis C

The study assessed whether the increased production of interleukin-1α (IL-1α) and interleukin-1β (IL-1β), as a result of chronic hepatic inflammation, could be the expression of the negative impact on periodontal disease. The study included chronic periodontitis patients who were systemically healthy, chronic periodontitis patients suffering from chronic hepatitis C, as well as control patients, being systemically and periodontally healthy. After periodontal examination and the assessment of certain periodontal parameters, gingival crevicular fluid was collected from all participating patients. By using the enzyme-linked immunosorbent assay method, a quantitative assessment of IL-1α and IL-1β levels was possible. The immunologic results were correlated to the clinical periodontal data. The gingival fluid levels of cytokines were higher for periodontitis patients with chronic hepatitis C than for the systemically healthy periodontitis patients (1.8-fold higher for IL-1α and 2.1-fold higher for IL-1β). In addition, the gingival fluid cytokine levels were significantly higher for the periodontal patients (with/without chronic hepatitis C) than for the control group. Positive correlations were found between gingival fluid IL-1α and IL-1β levels and certain clinical periodontal parameters or the age of the viral hepatitis C diagnosis, in periodontitis patients with chronic hepatitis C. The chronic hepatic inflammation may have an important additional negative impact on the periodontal status, as both inflammatory reactions seem to be promoted by common pro-inflammatory cytokines.

Oral Fluid Biomarkers for Diagnosing Gingivitis in Human: A Cross-Sectional Study

Diagnoses based on oral fluid biomarkers have been introduced to overcome limitations of periodontal probe-based diagnoses. Diagnostic ability of certain biomarkers for periodontitis have been identified and widely studied, however, such studies targeting gingivitis is scarce. The aims of this study were to determine and compare the efficacies and accuracies of eight biomarkers in diagnosing gingivitis with the aid of receiver operating characteristic (ROC) curves. The probing depth (PD), clinical attachment loss (CAL), bleeding on probing (BOP), gingival index (GI), and plaque index (PI) were examined in 100 participants. Gingival crevicular fluid was collected using paper points, and whole-saliva samples were collected using cotton roll. Samples were analyzed using enzyme-linked immunosorbent assay kits for the different biomarkers. The levels of matrix metalloproteinase (MMP)-8, MMP-9, lactoferrin, cystatin C, myeloperoxidase (MPO), platelet-activating factor, cathepsin B, and pyridinoline cross-linked carboxyterminal telopeptide of type I collagen were analyzed. MPO and MMP-8 levels in saliva were strongly correlated with gingivitis, with Pearson’s correlation coefficients of 0.399 and 0.217, respectively. The area under the curve (AUC) was largest for MMP-8, at 0.814, followed by values of 0.793 and 0.777 for MPO and MMP-9, respectively. The clinical parameters of GI and PI showed strong correlations and large AUC values, whereas PD and CAL did not. MMP-8 and MPO were found to be effective for diagnosing gingivitis. Further investigations based on the results of this study may identify clinically useful biomarkers for the accurate and early detection of gingivitis.

Rapid diagnosis of periodontitis, a feasibility study using MALDI-TOF mass spectrometry

AIM

The aim of the present study was to assess the feasibility and diagnostic contribution of protein profiling using MALDI-TOF mass spectrometry applied to saliva, gingival crevicular fluid (GCF) and dental plaque from periodontitis and healthy subjects. We hypothesized that rapid routine and blinded MALDI-TOF analysis could accurately classify these three types of samples according to periodontal state.

MATERIALS AND METHODS

Unstimulated saliva, GCF and dental plaque, collected from periodontitis subjects and healthy controls, were analyzed by MALDI-TOF MS. Based on the differentially expressed peaks between the two groups, diagnostic decision trees were built for each sample.

RESULTS

Among 141 patients (67 periodontitis and 74 healthy controls), the decision trees diagnosed periodontitis with a sensitivity = 70.3% (± 0.211) and a specificity = 77.8% (± 0.165) for saliva, a sensitivity = 79.6% (± 0.188) and a specificity = 75.7% (± 0.195) for GCF, and a sensitivity = 72.1% (± 0.202) and a specificity = 72.2% (± 0.195) for dental plaque. The sensitivity and specificity of the tests were improved to 100% (CI 95% = [0.91;1]) and 100% (CI 95% = [0.92;1]), respectively, when two samples were tested.

CONCLUSION

We developed, for the first time, diagnostic tests based on protein profiles of saliva, GCF and dental plaque between periodontitis patients and healthy subjects. When at least 2 of these samples were tested, the best results were obtained.

The Role of Medicine and Technology in Shaping the Future of Oral Health

This commentary describes the changes taking place in dentistry and speculates on improvements that could happen soon. Advances in health care will have an impact on the integration and delivery of oral care; conversely, there is growing acceptance that oral health impacts systemic health. Technological innovations are changing the face of medical care and are quickly becoming integrated into dentistry. Advances in novel antimicrobials, genomics, robotics and artificial intelligence are transforming our ability to diagnose and manage disease.

Salivary total Immunoglobulin G as a surrogate marker of oral immune activity in salivary bioscience research

The integration of salivary biomeasures in biobehavioral, psychophysiological, and clinical research has greatly expanded our ability to study the biopsychosocial processes underlying health. Much of this research, however, has failed to adequately assess and adjust for the impact of oral immune activity on salivary biomeasure concentrations and associations with serum levels. Aiming to improve the validity and reliability of salivary biomeasure data, we examine salivary total Immunoglobulin G (IgG) as a potential surrogate marker of oral inflammation and immune activity. During a single study visit in Baltimore, Maryland, healthy young adult participants provided matched blood and saliva samples (N=99; age 18-37 years, 42% female) and completed an oral health questionnaire. Biospecimens were assayed for total IgG and immune markers related to inflammation (cytokines), blood in saliva (transferrin), and tissue remodeling (matrix metalloproteinase-8). Total IgG (μg/mL) concentrations were higher in serum than saliva. Salivary total IgG was associated with some self-reported oral health measures, and strongly positively associated with all salivary immune markers. Controlling for salivary total IgG may be a feasible, affordable approach to adjusting salivary biomeasure findings for the influence of the oral immune environment when it is not possible or practical to obtain clinical oral health data.

Accuracy of single molecular biomarkers in saliva for the diagnosis of periodontitis: A systematic review and meta-analysis

AIM

To analyse, using a meta-analytical approach, the diagnostic accuracy of single molecular biomarkers in saliva for the detection of periodontitis in systemically healthy subjects.

MATERIALS AND METHODS

Articles on molecular biomarkers in saliva providing a binary contingency table (or sensitivity and specificity values and group sample sizes) in individuals with clinically diagnosed periodontitis were considered eligible. Searches for candidate articles were conducted in six electronic databases. The methodological quality was assessed through the tool Quality Assessment of Diagnostic Studies. Meta-analyses were performed using the Hierarchical Summary Receiver Operating Characteristic model.

RESULTS

Meta-analysis was possible for 5 of the 32 biomarkers studied. The highest values of sensitivity for the diagnosis of periodontitis were obtained for IL1beta (78.7%), followed by MMP8 (72.5%), IL6 and haemoglobin (72.0% for both molecules); the lowest sensitivity value was for MMP9 (70.3%). In terms of specificity estimates, MMP9 had the best result (81.5%), followed by IL1beta (78.0%) and haemoglobin (75.2%); MMP8 had the lowest specificity (70.5%).

CONCLUSIONS

MMP8, MMP9, IL1beta, IL6 and Hb were salivary biomarkers with good capability to detect periodontitis in systemically healthy subjects. MMP8 and IL1beta are the most researched biomarkers in the field, both showing clinically fair effectiveness for the diagnosis of periodontitis.

Salivary proteome characterization of alcohol and tobacco dependents

BACKGROUND

Alcohol and substances found in tobacco may alter salivary flow and amount of saliva proteins. This study aimed to compare salivary proteins between alcohol dependent smokers and controls.

METHODS

This is a case-control study with men older than 18 years of age, matched by age. The alcohol-dependent group was composed by heavy smokers and alcohol consumers. Unstimulated whole saliva was collected from all subjects. Analysis of digested peptides was performed in mass spectrometer. Data were processed using ProteinLynx GlobalServer software. Results were obtained by searching theHomo sapiens database from the UniProt catalog. The search tool IBI-IMIM was used to identify candidate proteins for biomarkers.

RESULTS

Alcohol-dependent and control groups were composed of nine participants each, with mean age of 36.89 ± 2.57 and 35.78 ± 1.64 years, respectively. 404 salivary proteins were found in both groups; 282 in the alcohol-dependent. Among the 96 proteins presented in both groups, 32 were up-regulated in the alcohol dependents (i.e. "Hemoglobin subunit beta" and "Forkhead box protein P2" were up-regulated at least 10-fold), 23 were down-regulated (i.e. "Statherin" and "RNA-binding protein 25" were down-regulated at least 10-fold), and 41 presented similar expression in both groups. 71 proteins were candidates for biomarkers of disorders 58 presented in alcohol dependents' saliva. The most common disorders were neoplasms, genetic, cardiovascular, metabolic and glandular diseases.

CONCLUSIONS

Salivary protein profile undergoes strong changes in alcohol and tobacco dependents. 34% of salivary proteins present in alcohol and tobacco dependents were present in controls; 14.5% of them were expressed in similar quantity.

Salivary levels of specialized pro-resolving lipid mediators as indicators of periodontal health/disease status

AIM

This cross-sectional case-control study aimed to determine if salivary levels of lipoxin A4 (LXA4), protectin D1 (PD1), resolvin E1 (RvE1) and maresin 1 (MaR1) might constitute a reflection of periodontal health/disease status.

MATERIALS AND METHODS

One hundred and two periodontitis patients and 61 healthy controls were recruited. Periodontal clinical status was determined by criteria based on full-mouth clinico-radiographical data. Salivary concentration of the analytes was calculated by enzyme-linked immunosorbent assay. The association between the biomarkers with disease status was assessed individually and adjusted for confounding using multivariate binary logistic regression models.

RESULTS

Significantly decreased LXA4 and increased PD1/MaR1 salivary levels were detected in periodontitis patients in comparison with healthy controls. However, no significant differences were observed for RvE1 levels between clinical groups. Clinical parameters such as probing depth, clinical attachment loss and extent were negatively correlated with LXA4, positively correlated with PD1/MaR1 and not correlated with RvE1 salivary levels. Logistic regression analyses revealed a strong/independent association of LXA4, PD1 and MaR1 salivary levels regarding disease status. Interaction effects between demographic predictor variables and salivary concentration of LXA4, PD1 and MaR1 were also identified.

CONCLUSION

The results of this study demonstrated a strong/independent association between reduced LXA4 and increased PD1/MaR1 salivary levels with periodontitis suggesting an imbalance in the specialized pro-resolving lipid mediators (SPMs) in periodontal disease.

Decreased salivary concentration of CD9 and CD81 exosome-related tetraspanins may be associated with the periodontal clinical status

AIM

This cross-sectional case-control study was designed to determine the association of the salivary concentration of CD9/CD81 exosome-related tetraspanins with the periodontal clinical status.

MATERIALS AND METHODS

Saliva samples from 104 periodontitis patients and 45 healthy controls were collected. Periodontal status was assessed based on full-mouth clinico-radiographical data, and salivary concentration of the analytes was calculated by ELISA. The association between the biomarkers with disease status was analysed using multivariate binary logistic regression models.

RESULTS

Significantly decreased salivary levels of CD9 and CD81 exosomes were detected in periodontitis patients in comparison with healthy controls. Also, negative significant correlations between salivary concentrations of CD9/CD81 exosomes regarding clinical measurements were observed. Likewise, a significant downward trend of the concentration of these two biomarkers concerning the stage and grade of disease could be identified. Logistic regression analyses revealed a strong/independent association for decreased salivary concentration of CD81 exosomes regarding disease status. Confounding and interaction effects between age and salivary concentration of CD9 exosomes were also noted.

CONCLUSION

Reduced salivary concentration of CD9/CD81 exosomes might be of significance in the context of periodontal disease pathogenesis.

Hyperoxia reduces salivary secretion by inducing oxidative stress in mice

OBJECTIVE

The aim of this study was to determine the effects of prolonged hyperoxia on salivary glands and salivary secretion in mice.

DESIGN

Male C57BL/6 J mice were kept in a 75% oxygen chamber (hyperoxia group) or a 21% oxygen chamber for 5 days. We measured the secretion volume, protein concentration, and amylase activity of saliva after the injection of pilocarpine. In addition, we evaluated the histological changes induced in the submandibular glands using hematoxylin and eosin and Alcian blue staining and assessed apoptotic changes using the TdT-mediated dUTP nick end labeling (TUNEL) assay. We also compared the submandibular gland expression levels of heme oxygenase-1 (HO-1), superoxide dismutase (SOD)-1, and SOD-2 using the real-time polymerase chain reaction.

RESULTS

In the hyperoxia group, salivary secretion was significantly inhibited at 5 and 10 min after the injection of pilocarpine, and the total salivary secretion volume was significantly decreased. The salivary protein concentration and amylase activity were also significantly higher in the hyperoxia group. In the histological examinations, enlargement of the mucous acini and the accumulation of mucins were observed in the submandibular region in the hyperoxia group, and the number of TUNEL-positive cells was also significantly increased in the hyperoxia group. Moreover, the expression levels of HO-1, SOD-1, and SOD-2 were significantly higher in the hyperoxia group.

CONCLUSION

Our results suggest that hyperoxia reduces salivary secretion, and oxidative stress reactions might be involved in this.

Top-down proteomic profiling of human saliva in multiple sclerosis patients

Multiple sclerosis is a chronic disease of the central nervous system characterized by inflammation, demyelination and neurodegeneration which is of undetermined origin. To date a single diagnostic test of multiple sclerosis does not exists and novel biomarkers are demanded for a more accurate and early diagnosis. In this study, we performed the quantitative analysis of 119 salivary peptides/proteins from 49 multiple sclerosis patients and 54 healthy controls by a mass spectrometry-based top-down proteomic approach. Statistical analysis evidenced different levels on 23 proteins: 8 proteins showed lower levels in multiple sclerosis patients with respect to controls and they were mono- and di-oxidized cystatin SN, mono- and di-oxidized cystatin S1, mono-oxidized cystatin SA and mono-phosphorylated statherin. 15 proteins showed higher levels in multiple sclerosis patients with respect to controls and they were antileukoproteinase, two proteoforms of Prolactin-Inducible Protein, P-C peptide (Fr.1-14, Fr. 26-44, and Fr. 36-44), SV1 fragment of statherin, cystatin SN Des_1-4, cystatin SN P₁₁ → L variant, and cystatin A T₉₆ → M variant. The differences observed between the salivary proteomic profile of patients suffering from multiple sclerosis and healthy subjects is consistent with the inflammatory condition and altered immune response typical of the pathology. Data are available via ProteomeXchange with identifier PXD009440.

SIGNIFICANCE

To date a single diagnostic test of multiple sclerosis does not exist, and diagnosis is based on multiple tests which mainly include the analysis of cerebrospinal fluid. However, the need for lumbar puncture makes the analysis of cerebrospinal fluid impractical for monitoring disease activity and response to treatment. The possible use of saliva as a diagnostic fluid for oral and systemic diseases has been largely investigated, but only marginally in multiple sclerosis compared to other body fluids. Our study demonstrates that the salivary proteome of multiple sclerosis patients differs considerably compared to that of sex and age matched healthy individuals and suggests that some differences might be associated with the different disease-modifying therapy used to treat multiple sclerosis patients.

Salivary exRNA biomarkers to detect gingivitis and monitor disease regression

AIM

This study tests the hypothesis that salivary extracellular RNA (exRNA) biomarkers can be developed for gingivitis detection and monitoring disease regression.

MATERIALS AND METHODS

Salivary exRNA biomarker candidates were developed from a total of 100 gingivitis and non-gingivitis individuals using Affymetrix's expression microarrays. The top 10 differentially expressed exRNAs were tested in a clinical cohort to determine whether the discovered salivary exRNA markers for gingivitis were associated with clinical gingivitis and disease regression. For this purpose, unstimulated saliva was collected from 30 randomly selected gingivitis subjects, the gingival and plaque indexes scores were taken at baseline, 3 and 6 weeks and salivary exRNAs were assayed by means of reverse transcription quantitative polymerase chain reaction.

RESULTS

Eight salivary exRNA biomarkers developed for gingivitis were statistically significantly changed over time, consistent with disease regression. A panel of four salivary exRNAs [SPRR1A, lnc-TET3-2:1, FAM25A, CRCT1] can detect gingivitis with a clinical performance of 0.91 area under the curve, with 71% sensitivity and 100% specificity.

CONCLUSIONS

The clinical values of the developed salivary exRNA biomarkers are associated with gingivitis regression. They offer strong potential to be advanced for definitive validation and clinical laboratory development test.

Clinical and radiographic periodontal status and whole salivary cotinine, IL-1β and IL-6 levels in cigarette- and waterpipe-smokers and E-cig users

The aim was to compare the clinical (plaque index [PI], bleeding on probing [BOP], probing pocket depth [PPD] and clinical attachment loss [CAL]) and radiographic (marginal bone loss [MBL]) periodontal parameters and whole salivary cotinine, interleukin (IL)-1β and IL-6 levels among cigarette-smokers, waterpipe-smokers, E-cig users and never-smokers. In total, 154 male individuals (39 cigarette-smokers, 40 waterpipe-smokers, 37 E-cig users and 38 never-smokers) were included. Full mouth PI, BOP, PPD and CAL were measured on all teeth (excluding third molars); and MBL was measured in digital intra-oral radiographs. Unstimulated whole salivary flow rate (UWSFR) and whole salivary cotinine, IL-1β and IL-6 levels were measured. Group comparisons were performed using one way analysis of variance and Bonferroni post-hoc tests. P-values less than 0.05 were considered statistically significant. There was no difference in UWSFR among the groups. Cotinine levels were significantly higher among cigarette- (P < 0.001) and waterpipe-smokers (P < 0.001) and E-cig users (P < 0.001) than never-smokers. IL-1β (P < 0.01) and IL-6 (P < 0.01) levels were significantly higher among cigarette- and waterpipe-smokers than E-cig users and never-smokers. There was no difference in PPD, CAL, mesial and distal MBL and whole salivary IL-1β and IL-6 levels among E-cig users and never-smokers. In conclusion, clinical and radiographic parameters of periodontal inflammation were poorer in cigarette and waterpipe smokers than E-cig users and never-smokers; and whole salivary cotinine levels were similar in all groups. Whole salivary IL-1β and IL-6 levels were higher in cigarette- and waterpipe-smokers than E-cig users and never-smokers.