Calprotectin levels in gingival crevicular fluid predict disease activity in patients treated for generalized aggressive periodontitis

Pathogenic associations between oral and gastrointestinal diseases

Both periodontitis and inflammatory bowel disease (IBD) are complex chronic conditions characterized by aberrant host immune response and dysregulated microbiota. Emerging data show an association between periodontitis and IBD, including direct and indirect mechanistic links between oral and intestinal inflammation. Direct pathways include translocation of proinflammatory microbes from the oral cavity to the gut and immune priming. Indirect pathways involve systemic immune activation with possible nonspecific effects on the gut. There are limited data on the effects of periodontal disease treatment on IBD course and vice versa, but early reports suggest that treatment of periodontitis decreases systemic immune activation and that treatment of IBD is associated with periodontitis healing, underscoring the importance of recognizing and treating both conditions.

Calprotectin and N-telopeptide of Type I Collagen (NTx) as Gingival Crevicular Fluid (GCF) Biomarker in Peri-Implantitis Patients

Introduction: Formulation of various preventive and therapeutic strategies is possible only by a better understanding of the immune-inflammatory profile of peri-implant diseases. For understanding the changes and turnover of bone, various markers have been used in the past literature, out of which, N-telopeptide of Type I Collagen (NTx) is acknowledged to be the most reliable marker.

Aims and objectives: Assessment of calprotectin and NTx concentration in gingival crevicular fluid (GCF) around the implant sites in subjects suffering from peri-implantitis.

Materials and methods: In total, 70 healthy individuals were included in the present study. These patients had opted for dental implants within the last decade. After collecting the peri-implant crevicular fluid (PICF) and GCF, various examinations were carried out. PICF samples were obtained with the help of sterile paper available in the form of strips. The enzyme-linked immunosorbent assay (ELISA) technique was used for measuring the calprotectin and NTx. All the readings were obtained in nanograms per microliter of PICF. All the results were recorded and analyzed.

Results: The overall mean calprotectin and NTx values were observed to be in a significantly higher range within the sites suffering from peri-implantitis when compared with healthy locations. The calprotectin values and NTx levels were positively correlated with the mean values of periodontal parameters observed clinically.

Conclusion: Both calprotectin and NTx could be used as a biomarker signifying the presence of inflammation as well as bone resorption in patients suffering from peri-implantitis.

Antimicrobial peptides: Defending the mucosal epithelial barrier

The recent epidemic caused by aerosolized SARS-CoV-2 virus illustrates the importance and vulnerability of the mucosal epithelial barrier against infection. Antimicrobial proteins and peptides (AMPs) are key to the epithelial barrier, providing immunity against microbes. In primitive life forms, AMPs protect the integument and the gut against pathogenic microbes. AMPs have also evolved in humans and other mammals to enhance newer, complex innate and adaptive immunity to favor the persistence of commensals over pathogenic microbes. The canonical AMPs are helictical peptides that form lethal pores in microbial membranes. In higher life forms, this type of AMP is exemplified by the defensin family of AMPs. In epithelial tissues, defensins, and calprotectin (complex of S100A8 and S100A9) have evolved to work cooperatively. The mechanisms of action differ. Unlike defensins, calprotectin sequesters essential trace metals from microbes, which inhibits growth. This review focuses on defensins and calprotectin as AMPs that appear to work cooperatively to fortify the epithelial barrier against infection. The antimicrobial spectrum is broad with overlap between the two AMPs. In mice, experimental models highlight the contribution of both AMPs to candidiasis as a fungal infection and periodontitis resulting from bacterial dysbiosis. These AMPs appear to contribute to innate immunity in humans, protecting the commensal microflora and restricting the emergence of pathobionts and pathogens. A striking example in human innate immunity is that elevated serum calprotectin protects against neonatal sepsis. Calprotectin is also remarkable because of functional differences when localized in epithelial and neutrophil cytoplasm or released into the extracellular environment. In the cytoplasm, calprotectin appears to protect against invasive pathogens. Extracellularly, calprotectin can engage pathogen-recognition receptors to activate innate immune and proinflammatory mechanisms. In inflamed epithelial and other tissue spaces, calprotectin, DNA, and histones are released from degranulated neutrophils to form insoluble antimicrobial barriers termed neutrophil extracellular traps. Hence, calprotectin and other AMPs use several strategies to provide microbial control and stimulate innate immunity.

Levels of myeloid-related proteins in saliva for screening and monitoring of periodontal disease

AIM

To evaluate the salivary levels of myeloid-related markers in relation to periodontal disease and their potential screening capability, as well as the effects of periodontal treatment on these markers in periodontitis patients.

MATERIALS AND METHODS

Participants with a healthy periodontium (n = 60) and with gingivitis (n = 63) and periodontitis (n = 72) were recruited. Periodontitis patients received non-surgical treatment and were re-examined after 3 and 6 months. Unstimulated saliva was collected at baseline and at 1, 3, and 6 months after therapy for the periodontitis patients. Levels of colony-stimulating factor-1 (CSF-1), interleukin-34 (IL-34), S100A8/A9, S100A12, hepatocyte growth factor (HGF), IL-1β, and matrix metalloproteinase-8 (MMP-8) were analysed by immunoassays.

RESULTS

CSF-1, S100A8/A9, S100A12, IL-1β, MMP-8, and HGF were significantly elevated in saliva from periodontitis and gingivitis patients in comparison to healthy individuals, whereas IL-34 was significantly lower in periodontitis compared to both healthy individuals and gingivitis patients. IL-34 increased significantly 3 months after treatment, while IL-1β and MMP-8 decreased 1 month after therapy. Additionally, periodontitis patients clustered in high and low levels of S100A8/A9, whereby those with high levels had more bleeding, deeper pockets, and higher S100A12.

CONCLUSIONS

Salivary levels of myeloid-related markers are altered in periodontitis and are partially modulated by periodontal treatment. Measuring S100A8/A9 in saliva may identify distinct groups of periodontitis patients.

Salivary MRP-8/14 and the presence of periodontitis-associated bacteria in children with bonded maxillary expansion treatment

OBJECTIVES

The aim of this study was to investigate changes in saliva concentration of the inflammatory marker MRP-8/14 and the presence of some periodontitis-associated bacteria in patients with mixed dentition treated with a rigid acrylic, bonded maxillary expander.

METHODS

Fifteen patients in mixed dentition treated with a bonded palatal expander were enrolled in this longitudinal study. Saliva samples were taken before the therapy, as well as in 2 weeks and 3, 6, 9, and 12 months after the beginning of the therapy. In each sample, the levels of MRP-8/14 were determined by ELISA and the presence of 11 bacteria was detected by PCR followed by DNA-DNA hybridization.

RESULTS

Salivary concentration of MRP-8/14 and the amount of Tannerella forsythia, Treponema denticola, and Eikenella corrodens were significantly increased during treatment with bonded maxillary expander. These changes were transient and the maximal levels of MRP-8/14 and periodontitis-associated pathogens were observed 6-9 months after the beginning of the therapy.

CONCLUSION

Therapy with bonded maxillary results in higher MRP-8/14 levels and increased prevalence of some periodontitis-associated bacteria, namely T. forsythia, T. denticola, and E. corrodens. The results suggest the detection of salivary MRP-8/14 levels may be a potential tool to reflect the oral health status in children with fixed orthodontic treatment.

CLINICAL RELEVANCE

Our data suggest that the treatment with bonded maxillary expander might influence the oral health status and should be accompanied by the careful control of the oral health during the therapy.

Adjunctive systemic antimicrobials for the non-surgical treatment of periodontitis

BACKGROUND

Systemic antimicrobials can be used as an adjunct to mechanical debridement (scaling and root planing (SRP)) as a non-surgical treatment approach to manage periodontitis. A range of antibiotics with different dosage and combinations are documented in the literature. The review follows the previous classification of periodontitis as all included studies used this classification.

OBJECTIVES

To assess the effects of systemic antimicrobials as an adjunct to SRP for the non-surgical treatment of patients with periodontitis.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases to 9 March 2020: Cochrane Oral Health's Trials Register, CENTRAL, MEDLINE, and Embase. The US National Institutes of Health Ongoing Trials Register ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) which involved individuals with clinically diagnosed untreated periodontitis. Trials compared SRP with systemic antibiotics versus SRP alone/placebo, or with other systemic antibiotics.

DATA COLLECTION AND ANALYSIS

We selected trials, extracted data, and assessed risk of bias in duplicate. We estimated mean differences (MDs) for continuous data, with 95% confidence intervals (CIs). We assessed the certainty of the evidence using GRADE.

MAIN RESULTS

We included 45 trials conducted worldwide involving 2664 adult participants. 14 studies were at low, 8 at high, and the remaining 23 at unclear overall risk of bias. Seven trials did not contribute data to the analysis. We assessed the certainty of the evidence for the 10 comparisons which reported long-term follow-up (≥ 1 year). None of the studies reported data on antimicrobial resistance and patient-reported quality of life changes. Amoxicillin + metronidazole + SRP versus SRP in chronic/aggressive periodontitis: the evidence for percentage of closed pockets (MD -16.20%, 95% CI -25.87 to -6.53; 1 study, 44 participants); clinical attachment level (CAL) (MD -0.47 mm, 95% CI -0.90 to -0.05; 2 studies, 389 participants); probing pocket depth (PD) (MD -0.30 mm, 95% CI -0.42 to -0.18; 2 studies, 389 participants); and percentage of bleeding on probing (BOP) (MD -8.06%, 95% CI -14.26 to -1.85; 2 studies, 389 participants) was of very low certainty. Only the results for closed pockets and BOP showed a minimally important clinical difference (MICD) favouring amoxicillin + metronidazole + SRP. Metronidazole + SRP versus SRP in chronic/aggressive periodontitis: the evidence for percentage of closed pockets (MD -12.20%, 95% CI -29.23 to 4.83; 1 study, 22 participants); CAL (MD -1.12 mm, 95% CI -2.24 to 0; 3 studies, 71 participants); PD (MD -1.11 mm, 95% CI -2.84 to 0.61; 2 studies, 47 participants); and percentage of BOP (MD -6.90%, 95% CI -22.10 to 8.30; 1 study, 22 participants) was of very low certainty. Only the results for CAL and PD showed an MICD favouring the MTZ + SRP group. Azithromycin + SRP versus SRP for chronic/aggressive periodontitis: we found no evidence of a difference in percentage of closed pockets (MD 2.50%, 95% CI -10.19 to 15.19; 1 study, 40 participants); CAL (MD -0.59 mm, 95% CI -1.27 to 0.08; 2 studies, 110 participants); PD (MD -0.77 mm, 95% CI -2.33 to 0.79; 2 studies, 110 participants); and percentage of BOP (MD -1.28%, 95% CI -4.32 to 1.76; 2 studies, 110 participants) (very low-certainty evidence for all outcomes). Amoxicillin + clavulanate + SRP versus SRP for chronic periodontitis: the evidence from 1 study, 21 participants for CAL (MD 0.10 mm, 95% CI -0.51 to 0.71); PD (MD 0.10 mm, 95% CI -0.17 to 0.37); and BOP (MD 0%, 95% CI -0.09 to 0.09) was of very low certainty and did not show a difference between the groups. Doxycycline + SRP versus SRP in aggressive periodontitis: the evidence from 1 study, 22 participants for CAL (MD -0.80 mm, 95% CI -1.49 to -0.11); and PD (MD -1.00 mm, 95% CI -1.78 to -0.22) was of very low certainty, with the doxycycline + SRP group showing an MICD in PD only. Tetracycline + SRP versus SRP for aggressive periodontitis: we found very low-certainty evidence of a difference in long-term improvement in CAL for the tetracycline group (MD -2.30 mm, 95% CI -2.50 to -2.10; 1 study, 26 participants). Clindamycin + SRP versus SRP in aggressive periodontitis: we found very low-certainty evidence from 1 study, 21 participants of a difference in long-term improvement in CAL (MD -1.70 mm, 95% CI -2.40 to -1.00); and PD (MD -1.80 mm, 95% CI -2.47 to -1.13) favouring clindamycin + SRP. Doxycycline + SRP versus metronidazole + SRP for aggressive periodontitis: there was very low-certainty evidence from 1 study, 27 participants of a difference in long-term CAL (MD 1.10 mm, 95% CI 0.36 to 1.84); and PD (MD 1.00 mm, 95% CI 0.30 to 1.70) favouring metronidazole + SRP. Clindamycin + SRP versus metronidazole + SRP for aggressive periodontitis: the evidence from 1 study, 26 participants for CAL (MD 0.20 mm, 95% CI -0.55 to 0.95); and PD (MD 0.20 mm, 95% CI -0.38 to 0.78) was of very low certainty and did not show a difference between the groups. Clindamycin + SRP versus doxycycline + SRP for aggressive periodontitis: the evidence from 1 study, 23 participants for CAL (MD -0.90 mm, 95% CI -1.62 to -0.18); and PD (MD -0.80 mm, 95% CI -1.58 to -0.02) was of very low certainty and did not show a difference between the groups. Most trials testing amoxicillin, metronidazole, and azithromycin reported adverse events such as nausea, vomiting, diarrhoea, mild gastrointestinal disturbances, and metallic taste. No serious adverse events were reported.

AUTHORS' CONCLUSIONS

There is very low-certainty evidence (for long-term follow-up) to inform clinicians and patients if adjunctive systemic antimicrobials are of any help for the non-surgical treatment of periodontitis. There is insufficient evidence to decide whether some antibiotics are better than others when used alongside SRP. None of the trials reported serious adverse events but patients should be made aware of the common adverse events related to these drugs. Well-planned RCTs need to be conducted clearly defining the minimally important clinical difference for the outcomes closed pockets, CAL, PD, and BOP.

Local IL-10 level as a predictive factor in generalized aggressive periodontitis treatment response

Generalized aggressive periodontitis (GAgP) presents a reduced response to non-surgical therapy. However, it is not clear if the initial clinical, microbiological or immunological characteristics are impacting the worse response to treatment. This study aimed to identify the predictive value of clinical, microbiological and immunological patterns on the clinical response to therapy in GAgP patients. Twenty-four GAgP patients were selected, and gingival crevicular fluid (GCF) and subgingival biofilm were collected. Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Tannerella forsythia levels were evaluated by qPCR, and IL-1β and IL-10 concentration by ELISA. Twelve patients were treated with SRP (scaling and root planning), and twelve with SRP plus 375 mg amoxicillin and 250 mg metronidazole (8/8 hours, 7 days) (SRP + AM). The clinical changes (Probing Pocket Depth [PPD] reduction and Clinical Attachment Level [CAL] gain) 6 months post-treatment were correlated to the initial clinical, inflammatory and microbiological variables using stepwise logistic regression (α = 5%). CAL gain at 6 months was 1.16 ± 0.77 for SRP and 1.74 ± 0.57 mm for SRP + AM (P > .05). PPD reduction was 1.96 ± 0.82 for SRP and 2.45 ± 0.77 mm for SRP + AM (P < .05). In the SRP group, IL-10 showed a predictive value for clinical response. The higher the IL-10 concentration at baseline, the higher the reduction in PPD at 6 months (P = .01, r = .68). However, when antimicrobials were administered, no significant influence was detected (P > .05). It can be concluded that the IL-10 levels in GFC act as a predictor of clinical response to GAgP. Moreover, the intake of antimicrobials appears to overlap the influence of the inflammatory response on clinical response to treatment. Clinical trial registration number: NCT03933501.

Role of Calprotectin as a Biomarker in Periodontal Disease

Periodontal disease (PD) is a common infectious and inflammatory disease characterised by inflammation of tissues surrounding and supporting the teeth and destruction of the associated alveolar bone, eventually resulting in tooth loss. This disease is caused by periodontopathic bacteria in plaque biofilm and resultant innate and adaptive immune responses in periodontal tissues. Calprotectin (CLP) is a calcium-binding protein of the S-100 protein family and is found to be induced by activated granulocytes, monocytes, and epithelial cells. CLP has been shown to play an important role in numerous inflammatory diseases and disorders. Increasing evidence indicates that CLP is involved in the progression of PD, and its levels may be associated with disease severity and outcome of periodontal treatments. This review will summarise recent studies regarding the presence, regulation, and function of CLP in PD. The findings indicate that CLP may be an effective biomarker for diagnosis and treatment for the PD.

Calprotectin and cross-linked N-telopeptides of type I collagen levels in crevicular fluid from implant sites with peri-implant diseases: a pilot study

BACKGROUND

Peri-implant crevicular fluid (PICF) contains calprotectin and NTx, which are markers for inflammation and bone resorption, respectively. The aims of this pilot study were to compare calprotectin and NTx levels in PICF from implant sites with or without peri-implant diseases and to evaluate the usefulness of calprotectin and NTx as diagnostic markers for peri-implant diseases.

METHODS

Thirty-five patients with dental implants participated in this pilot study. PICF samples were collected from peri-implant disease sites (n = 40) and non-diseased (healthy) sites (n = 34) after clinical indicators including probing depth (PD), bleeding on probing (BOP), gingival index (GI), and bone loss (BL) rate were investigated. Calprotectin and NTx amounts in PICF were measured using their respective ELISA kits and then compared between diseased and healthy samples. The relationship between PICF calprotectin or NTx levels and clinical indicator levels was investigated. A receiver operating characteristic (ROC) curve analysis of calprotectin and NTx was performed to predict peri-implant diseases.

RESULTS

Calprotectin and NTx levels in PICF were significantly higher from peri-implant disease sites than from healthy sites. PICF calprotectin amounts correlated with PD, and its levels were significantly higher in the GI-1 and GI-2 groups than in the GI-0 group. PICF NTx amounts correlated with PD and the BL rate. ROC curves indicated that PICF calprotectin and NTx are useful biomarkers for peri-implant diseases.

CONCLUSIONS

Calprotectin and NTx in PICF have potential as biomarkers for the diagnosis of peri-implant diseases.

Comparison of clinical parameters, microbiological effects and calprotectin counts in gingival crevicular fluid between Er: YAG laser and conventional periodontal therapies: A split-mouth, single-blinded, randomized controlled trial

BACKGROUND

The erbium-doped yttrium, aluminum, and garnet (Er:YAG) laser is thought to be the most promising laser for periodontal treatment; however, its application is still under consideration. The aim of this study was to compare Er:YAG laser monotherapy with conventional scaling and root planing (SRP) for chronic periodontitis using clinical parameters, the detection rate of periodontal pathogens, and the calprotectin level in gingival crevicular fluid.

METHODS

Twenty-seven participants with moderate-to-advanced chronic periodontitis were included. In a split-mouth design, the 2 half-mouths of each participant were randomly assigned to Er:YAG laser or SRP (combination of ultrasonic and manual instruments) treatment. Clinical parameters were recorded at baseline, 6 weeks, and 3 and 6 months after treatment. At the same time points, gingival crevicular fluid was collected to analyze the detection rate of 6 periodontal pathogens by polymerase chain reaction and the levels of calprotectin by enzyme-linked immunosorbent assay.

RESULTS

Both treatment groups showed significant reductions in probing depth (PD), bleeding index (BI), and clinical attachment level (CAL) from baseline to 6 months. For sites with 4 mm ≤ PD ≤ 6 mm at baseline, SRP resulted in a greater reduction in PD and CAL than Er:YAG laser treatment, and the difference remained at 6 months post-treatment (P = .01 and P < .01, respectively). For sites with PD ≥7 mm at baseline, the clinical parameters showed similar results between the 2 groups. SRP resulted in a lower detection rate of Porphyromonas gingivalis at 6 months post-treatment. The levels of calprotectin were significantly decreased from baseline to 6 months in both groups, without a significant difference between the groups.

CONCLUSION

For mild pockets, conventional SRP may still be the preferred choice. For deep pockets, Er:YAG laser treatment could be an effective alternative. Studies are needed to explore more advanced instruments and new application methods for the Er:YAG laser for periodontal treatment in deep pockets.

Clinical significance of GCF sIL-6R and calprotectin to evaluate the periodontal inflammation

Background

Periodontitis is an inflammatory disease. The aim of this study was to investigate whether the soluble form of interleukin-6 receptor (sIL-6R) and calprotectin concentrations in gingival crevicular fluid are useful biomarkers in the evaluation of periodontitis.

Methods

First, a cross-sectional study was performed. A total of 34 periodontitis patients were enrolled and the gingival crevicular fluid samples were collected from the healthy and inflamed sites of periodontal pockets in each patient. The relationship between periodontal condition and gingival crevicular fluid sIL-6R and calprotectin concentrations was analysed statistically. The cut-off values of gingival crevicular fluid sIL-6R and calprotectin concentrations for the evaluation of periodontitis were determined using a receiver operating characteristic curve. Next, by using enzyme-linked immunosorbent assay, it was examined whether calprotectin induces sIL-6R production in THP-1 macrophages.

Results

Both gingival crevicular fluid sIL-6R and calprotectin concentrations were significantly higher in the inflamed sites than in the healthy sites ( P < 0.0001). The cut-off values of gingival crevicular fluid sIL-6R and calprotectin concentrations for the evaluation of periodontal inflammation were as follows: sIL-6R: 43.5 pg/site; calprotectin: 134.3 ng/site. In the in vitro study, calprotectin significantly induced sIL-6R production in THP-1 macrophages ( P < 0.01).

Conclusions

Both gingival crevicular fluid sIL-6R and calprotectin concentrations are significant biomarkers in the evaluation of periodontal inflammation.

Identification of Gingival Crevicular Fluid Sampling, Analytical Methods, and Oral Biomarkers for the Diagnosis and Monitoring of Periodontal Diseases: A Systematic Review

Background. Several studies in the last decades have focused on finding a precise method for the diagnosis of periodontal disease in its early stages. Aim. To evaluate from current scientific literature the most common and precise method for gingival crevicular fluid (GCF) sample collection, biomarker analytical methods, and the variability of biomarker quantification, even when using the same analytical technique. Methodology. An electronic search was conducted on in vivo studies that presented clinical data on techniques used for GCF collection and biomarker analysis. Results. The results showed that 71.1%, 24.7%, and 4.1% of the studies used absorption, microcapillary, and washing techniques, respectively, in their gingival crevicular fluid collection. 73.1% of the researchers analyzed their samples by using enzyme-linked immunosorbent assay (ELISA). 22.6%, 19.5%, and 18.5% of the researchers included interleukin-1 beta (IL-1β), matrix metalloproteinase-8 (MMP-8), and tumor necrosis factor-alpha (TNF-α), respectively, in their studies as biomarkers for periodontal disease. Conclusion. IL-1β can be considered among the most common biomarkers that give precise results and can be used as an indicator of periodontal disease progression. Furthermore, paper strips are the most convenient and accurate method for gingival crevicular fluid collection, while enzyme-linked immunosorbent assay can be considered the most conventional method for the diagnosis of biofluids.

Programmed cell death in periodontitis: recent advances and future perspectives

Periodontitis is a highly prevalent infectious disease, characterized by destruction of the periodontium, and is the main cause of tooth loss. Periodontitis is initiated by periodontal pathogens, while other risk factors including smoking, stress, and systemic diseases aggravate its progression. Periodontitis affects many people worldwide, but the molecular mechanisms by which pathogens and risk factors destroy the periodontium are unclear. Programmed cell death (PCD), different from necrosis, is an active cell death mediated by a cascade of gene expression events and can be mainly classified into apoptosis, autophagy, necroptosis, and pyroptosis. Although PCD is involved in many inflammatory diseases, its correlation with periodontitis is unclear. After reviewing the relevant published articles, we found that apoptosis has indeed been reported to play a role in periodontitis. However, the role of autophagy in periodontitis needs further verification. Additionally, implication of necroptosis or pyroptosis in periodontitis remains unknown. Therefore, we recommend future studies, which will unravel the pivotal role of PCD in periodontitis, allowing us to prevent, diagnose, and treat the disease, as well as predict its outcomes.

Comparative Analysis of Calcium-Binding Myeloid-Related Protein-8/14 in Saliva and Serum of Patients With Periodontitis and Healthy Individuals

BACKGROUND

This study aims to investigate calcium-binding myeloid-related protein (MRP)-8/14 in the saliva and serum of individuals with periodontitis and periodontally healthy individuals for the assessment of its role in the pathogenesis and clinical diagnosis of periodontitis.

METHODS

This cross-sectional study includes 56 patients with periodontitis and 44 periodontally healthy individuals. Saliva and serum were collected for the detection of MRP-8/14 and calcium levels. Periodontopathic bacteria were determined by polymerase chain reaction in saliva. Correlations between salivary and serum MRP-8/14 levels and clinical parameters, bacteria, and calcium were analyzed with Pearson correlation in a multiple regression model. MRP-8/14 levels were documented with receiver operating characteristic (ROC) curves.

RESULTS

Compared with healthy individuals, MRP-8/14 levels were significantly higher in both the saliva and serum of patients with periodontitis, but calcium was increased only in saliva. A high diagnostic potential of salivary MRP-8/14 was detected for periodontitis (ROC = 0.86). Salivary MRP-8/14 levels correlated significantly with the presence of the periodontopathogen Treponema denticola, as well as with the clinical parameters of periodontitis.

CONCLUSION

MRP-8/14 in saliva might be a potential diagnostic parameter for periodontal disease.

The pro-apoptotic and pro-inflammatory effects of calprotectin on human periodontal ligament cells

Calprotectin, a heterodimer of S100A8 and S100A9 subunits, is associated with inflammatory disorders such as rheumatoid arthritis and cystic fibrosis. Although calprotectin levels are increased significantly in the gingival crevicular fluid (GCF) of periodontitis patients, its effects on periodontal ligament cells (PDLCs) remain largely unknown. The aim of this study was to evaluate calprotectin levels in the GCF of generalized aggressive periodontitis (AgP) patients and to investigate the effects of recombinant human calprotectin (rhS100A8/A9) and its subunits (rhS100A8 and rhS100A9) in PDLCs. Both the concentration and amount of crevicular calprotectin were significantly higher in the AgP group compared with healthy controls. In addition, the GCF calprotectin levels were correlated positively with clinical periodontal parameters including bleeding index, probing depth, and clinical attachment loss. rhS100A8/A9 promoted cell apoptosis, whereas rhS100A8 and rhS100A9 individually exerted little effect on apoptosis in PDLCs. rhS100A9 and rhS100A8/A9 increased the activation of nuclear factor-κB (NF-κB) by promoting the nuclear translocation of p65 in PDLCs, subsequently inducing expression of the pro-inflammatory cytokines IL-6, IL-8, TNFα, and COX2. Treatment with an NF-κB inhibitor partially reversed the rhS100A9- and rhS100A8/A9-induced upregulation of the pro-inflammatory cytokines. rhS100A9, and not rhS100A8, was mainly responsible for the pro-inflammatory role of calprotectin. Collectively, our results suggest that calprotectin promotes apoptosis and the inflammatory response in PDLCs via rhS100A9. These findings might help identify novel treatments for periodontitis.