Diagnostic potential of endothelin-1 in peri-implant diseases: a cross-sectional study.

PURPOSE: This study aimed to evaluate the potential of Endothelin-1 (ET-1), a peptide derived from vascular endothelial cells, as a biomarker for diagnosing peri-implant diseases. METHODS: A cohort of 29 patients with a total of 76 implants was included in this study and subsequently divided into three groups based on peri-implant clinical parameters and radiographic examination: healthy (peri-implant health) (n = 29), mucositis (n = 22), and peri-implantitis (n = 25) groups. The levels of ET-1 (ρg/site) and interleukin (IL)-1ß (ρg/site) in peri-implant sulcus fluid (PISF) samples were determined using enzyme immunoassay. Statistical analyses were conducted using Kruskal-Wallis and Steel-Dwass tests. Logistic regression and receiver operating characteristic (ROC) curve analyses were performed to evaluate the diagnostic performance of the biomarkers. RESULTS: ET-1 levels were significantly elevated in the peri-implantitis group compared to those in the healthy group, and were highest in the peri-implant mucositis group. Additionally, IL-1ß levels were significantly higher in the peri-implantitis group than those in the healthy group. ROC curve analysis indicated that ET-1 exhibited superior area under the curve values, sensitivity, and specificity compared to those of IL-1ß. CONCLUSIONS: Our findings suggest that the presence of ET-1 in PISF plays a role in peri-implant diseases. Its significantly increased expression in peri-implant mucositis indicates its potential for enabling earlier and more accurate assessments of peri-implant inflammation when combined with conventional examination methods.

Diagnostic value of aMMP-8 and azurocidin in peri-implant sulcular fluid as biomarkers of peri-implant health or disease.

OBJECTIVE: The objective of this study was to investigate the effectiveness of testing for active matrix metalloproteinase-8 (aMMP-8) by a quantitative point-of-care (PoC), chairside lateral flow immunotest and azurocidin, in the peri-implant sulcular fluid (PISF), as biomarkers for the presence or absence of peri-implant diseases. BACKGROUND: Current research indicates that proinflammatory cytokines and extracellular matrix-degrading enzymes may be of value to diagnose and predict peri-implant disease initiation and progression, but more data are needed. METHODS: Eighty patients with implants were recruited. PISF samples were collected and quantitatively analyzed for aMMP-8 (chairside) and azurocidin with ELISA. Radiographic assessments and clinical indices (probing depth, probing attachment level, bleeding on probing, and plaque) were recorded after sampling. Kruskal-Wallis test and pairwise post hoc Dunn-Bonferroni test were used to relate aMMP-8 levels and azurocidin levels to clinical parameters. The diagnostic ability of aMMP-8 (ng/mL) and azurocidin was analyzed by receiver operator curve analysis. Area under the curve (AUC) was calculated and the Spearman's rho, and the coefficient of determination (R2) were used to calculate the correlations between aMMP-8, azurocidin, and periodontal parameters. RESULTS: Statistically significant differences were observed for aMMP-8 levels but not for azurocidin between healthy implants, implants with mucositis, and those with peri-implantitis (13.65 ± 7.18, 32.33 ± 21.20, and 73.07 ± 43.93 ng/mL, respectively), (Kruskall-Wallis test p < .05). The aMMP-8 test with a threshold of 20 ng/mL has a sensitivity of 71.7% and a specificity of 77.8% to identify peri-implantitis and healthy implants, respectively. AUC was found to be 0.814, and the accuracy of the method reaches 73.8%. Above a cutoff value of 33.7 ng/mL of aMMP-8, the accuracy of the test to detect peri-implantitis reaches 77.5% in relation to 62.5% of BoP from the same site. CONCLUSION: Taken collectively, present data indicate that the aMMP-8 PoC lateral flow immunotest can be a beneficial, adjunctive diagnostic quantitative tool for real-time screening for peri-implant diseases.

Evaluation of salivary stress markers and inflammatory cytokine levels in peri-implantitis patients.

BACKGROUND AND OBJECTIVE: Psychological stress has been identified in some observational studies as a potential factor that may modify and affect periodontal diseases, but there are no similar data for peri-implantitis. The aim of this study was to determine the relationship between interleukin (IL)-1ß, IL-6, IL-10, interferon (IFN)α inflammatory cytokines and the psychological stress-related markers, glucocorticoid receptor-α (GRα), and salivary α-amylase (sAA) gene expression levels in saliva samples obtained from healthy implants and peri-implantitis patients. MATERIALS AND METHODS: The study included a total of 50 systemically healthy subjects. Peri-implant clinical parameters were recorded and psychological stress level was evaluated with the hospital anxiety and depression scale (HAD) and state-trait anxiety inventory (STAI) questionnaire forms. Following the evaluations, the patients were divided into 4 groups according their stress and clinical status (Ia, Ib, IIa, IIb). IL-1ß, IL-6, IL-10, IFNα, GRα, sAA gene expression levels in the saliva samples were quantified by quantitative polymerase chain reaction (qPCR). RESULTS: In the group of peri-implantitis who had a high score in stress level assessment scales, significantly higher IL-1ß, IL-6, sAA expression levels were observed (p < 0.001). The IL-10 gene expression levels were lower in the groups with a high score in the stress level assessment scales (p < 0.001). GRα gene was expressed at lower levels in the group of peri-implantitis who had a high score in stress level assessment scales but the difference was not statistically significant (p = 0.065). CONCLUSION: The study findings suggest that psychological stress may increase the inflammation associated with peri-implantitis by affecting cytokine expression levels. CLINICAL RELEVANCE: To prevent peri-implantitis or reduce its prevalence, it could be beneficial to evaluate stress levels and identify individuals experiencing stress.

Ultrastructural and immunohistochemical evaluation of hyperplastic soft tissues surrounding dental implants in fibular jaws.

In reconstructive surgery, complications post-fibula free flap (FFF) reconstruction, notably peri-implant hyperplasia, are significant yet understudied. This study analyzed peri-implant hyperplastic tissue surrounding FFF, alongside peri-implantitis and foreign body granulation (FBG) tissues from patients treated at the Department of Oral and Maxillofacial Surgery, Seoul National University Dental Hospital. Using light microscopy, pseudoepitheliomatous hyperplasia, anucleate and pyknotic prickle cells, and excessive collagen deposition were observed in FFF hyperplastic tissue. Ultrastructural analyses revealed abnormal structures, including hemidesmosome dilation, bacterial invasion, and endoplasmic reticulum (ER) swelling. In immunohistochemical analysis, unfolded protein-response markers ATF6, PERK, XBP1, inflammatory marker NFκB, necroptosis marker MLKL, apoptosis marker GADD153, autophagy marker LC3, epithelial-mesenchymal transition, and angiogenesis markers were expressed variably in hyperplastic tissue surrounding FFF implants, peri-implantitis, and FBG tissues. NFκB expression was higher in peri-implantitis and FBG tissues compared to hyperplastic tissue surrounding FFF implants. PERK expression exceeded XBP1 significantly in FFF hyperplastic tissue, while expression levels of PERK, XBP1, and ATF6 were not significantly different in peri-implantitis and FBG tissues. These findings provide valuable insights into the interconnected roles of ER stress, necroptosis, apoptosis, and angiogenesis in the pathogenesis of oral pathologies, offering a foundation for innovative strategies in dental implant rehabilitation management and prevention.

Detection and comparison of neutrophil extracellular traps in tissue samples of peri-implantitis, periodontitis, and healthy patients: A pilot study.

OBJECTIVE: The aim of this study was to detect and compare the tissular expression of neutrophil extracellular traps (NETs) in peri-implant and periodontal samples of patients with peri-implantitis, periodontitis, and controls. MATERIALS AND METHODS: An observational study was performed on patients with peri-implantitis, periodontitis, and controls. Peri-implant and/or periodontal clinical examinations were performed on each participant. Tissue samples were collected during tooth/implant extraction for clinical reasons. Electron microscopy analysis, Picro-Sirius red staining, immunohistochemical (CD15), and immunofluorescence (citrullinated H3 and myeloperoxidase) techniques were performed to detect NET-related structures and the degree of connective tissue destruction, between the study groups. RESULTS: Sixty-four patients were included in the study: 28 peri-implantitis, 26 periodontitis, and 10 controls, with a total of 51 implants, 26 periodontal teeth, and 10 control teeth. Neutrophil release of nuclear content was observed in transmission electron microscopy. Immunohistochemical analysis showed a greater CD15 expression in both peri-implantitis and periodontitis compared to controls (p < 0.001), and peri-implantitis presented lower levels of connective tissue and collagen compared to both periodontitis (p = 0.044; p < 0.001) and controls (p < 0.001). Immunofluorescence showed greater citH3 expression in peri-implantitis than the one found in both periodontitis (p = 0.003) and controls (p = 0.048). CONCLUSIONS: A greater presence and involvement of neutrophils, as well as a greater connective tissue destruction were observed in cases of peri-implantitis. A higher expression of NET-related markers was found in mucosal samples of peri-implantitis compared to periodontitis and controls.

The role of oxidative stress biomarkers in the development of peri-implant disease: A systematic review and meta-analysis.

OBJECTIVES: To analyze the role of oxidative stress (OS) biomarkers in peri­implant diseases using a systematic review and meta-analysis approach. DATE: The review incorporated cross-sectional studies, randomized controlled trials, and case-control trials to evaluate the differences in OS biomarkers of peri­implant disease. SOURCES: A comprehensive literature search was conducted in electronic databases such as PubMed, Scopus, Embase, Web of Science, and CNKI, and no restrictions were applied during the search process. STUDY SELECTION: A total of 452 studies were identified, of which 18 were eligible for inclusion. Risk of bias and sensitivity analysis were assessed using Egger's test and funnel plots. RESULTS: We found that the levels of glutathione peroxidase (GSH-Px) in the peri­implant sulcus fluid (PISF) of patients with peri­implant diseases were significantly reduced (SMD = -1.40; 95 % CI = 1.70, -1.11; p < 0.001), while the levels of total myeloperoxidase (MPO) and malondialdehyde (MDA) were significantly increased (SMD = 0.46; 95 % CI = 0.12, 0.80; p = 0.008; SMD = 0.28; 95 % CI = 0.01, 0.56; p = 0.043). However, there were no significant differences of MPO concentration (SMD = 0.38; 95 % CI = -0.39, 1.15; p = 0.331) and superoxide dismutase (SOD)(SMD = -0.43; 95 % CI = -1.94, 1.07; p = 0.572) in PISF between peri­implant disease group and control group. Similarly, salivary MPO did not show significant differences (SMD = 1.62; 95 % CI = -1.01, 4.24; p = 0.227). CONCLUSIONS: Our results supported that the level of local OS biomarkers was closely related to peri­implant diseases. GSH-Px, total MPO and MDA may be PISF biomarkers with good capability to monitor the development of peri­implant disease. CLINICAL SIGNIFICANCE: This study found significant differences in the levels of local OS biomarkers (GSH-Px, total MPO, and MDA) between patients with peri­implant diseases and healthy subjects, which may be ideal candidate biomarkers for predicting and diagnosing peri­implant diseases.

Mass spectrometry-based proteomic applications in dental implants research.

Dental implants have been established as successful treatment options for missing teeth with steadily increasing demands. Today, the primary areas of research in dental implantology revolve around osseointegration, soft and hard tissue grafting as well as peri-implantitis diagnostics, prevention, and treatment. This review provides a comprehensive overview of the current literature on the application of MS-based proteomics in dental implant research, highlights how explorative proteomics provided insights into the biology of peri-implant soft and hard tissues and how proteomics facilitated the stratification between healthy and diseased implants, enabling the identification of potential new diagnostic markers. Additionally, this review illuminates technical aspects, and provides recommendations for future study designs based on the current evidence.

Reprogramming mitochondrial metabolism of macrophages by miRNA-released microporous coatings to prevent peri-implantitis.

Although various new biomaterials have enriched the methods for peri-implant inflammation treatment, their efficacy is still debated, and secondary operations on the implant area have also caused pain for patients. Recently, strategies that regulate macrophage polarization to prevent or even treat peri-implantitis have attracted increasing attention. Here, we prepared a laser-drilled and covered with metal organic framework-miR-27a agomir nanomembrane (L-MOF-agomir) implant, which could load and sustain the release of miR-27a agomir. In vitro, the L-MOF-agomir titanium plate promoted the repolarization of LPS-stimulated macrophages from M1 to M2, and the macrophage culture supernatant promoted BMSCs osteogenesis. In a ligation-induced rat peri-implantitis model, the L-MOF-agomir implants featured strong immunomodulatory activity of macrophage polarization and alleviated ligation-induced bone resorption. The mechanism of repolarization function may be that the L-MOF-agomir implants promote the macrophage mitochondrial function and metabolism reprogramming from glycolysis to oxidative phosphorylation. Our study demonstrates the feasibility of targeting cell metabolism to regulate macrophage immunity for peri-implantitis inhibition and provides a new perspective for the development of novel multifunctional implants.

Evaluation of IL-4, MIP-1α, and MMP-9 gene expression levels in peri-implant tissues in peri-implantitis.

This case-control study evaluated the gene expression levels of interleukin (IL)-4, macrophage inflammatory protein type 1 alpha (MIP-1α), and metalloproteinase (MMP)-9, factors involved in the formation of giant cells in healthy peri-implant tissue and peri-implantitis. Thirty-five subjects (15 healthy and 20 with peri-implantitis), who met the inclusion and exclusion criteria, were included in this study. The peri-implant tissue biopsies were subjected to total RNA extraction, DNAse treatment, and cDNA synthesis. Subsequently, the reaction of real-time PCR was performed to evaluate the gene expression levels of IL-4, MIP-1α, and MMP-9 concerning the reference gene. IL-4 gene expression showed higher (18-fold) values in the Peri-Implantitis Group of Patients when compared with the Healthy (Control) Group (p<0.0001). Although MIP- 1α and MMP-9 gene expression levels were higher in diseased implants, they showed no significant differences (p=0.06 and p=0.2337), respectively. Within the limitations of this study, the results showed that in tissues affected by peri-implantitis, only levels of Il-4 were increased when compared with tissues in the control group.

Revealing leukocyte populations in human peri-implantitis and periodontitis using flow cytometry.

OBJECTIVE: To identify, quantify, and characterize leukocyte populations in PI and periodontitis using flow cytometry. METHODS: Fresh biopsies from human PI and periodontitis lesions were processed to a single-cell suspension. The immune cell types were identified using flow cytometry. RESULTS: Twenty-one biopsies were obtained and analyzed corresponding to fourteen PI and seven periodontitis samples. Participants' average age was 63.95 ± 14.77 years without a significant difference between PI and periodontitis patients, the female/male ratio was 8/12, and mean PD was 8.5 ± 2.17. High similarity was found between periodontitis and PI in the main immune cell types. Out of the leukocytes, the PMN proportion was 40% in PI and 33% in periodontitis. T-cells 22% in PI and 18% in periodontitis. Similar proportions of B-cells 10% and macrophages 6% were found in PI and periodontitis. Dendritic and NK cells were found in low proportions (~ 1%) in PI and periodontitis. T-cell sub-analysis showed that CD4-positive were more prevalent than CD8-positive in both diseases (CD4/CD8 ratio of 1.2). CONCLUSION: With the use of flow cytometry analysis, the leukocyte populations in human peri-implantitis and periodontitis were classified. In PI and periodontitis, we identified similar proportions of specific (CD4/CD8) and innate (dendritic and NK) immune cells. These results corroborate previous histological studies. CLINICAL RELEVANCE: Flow cytometry analysis can be used to identify and quantify immune cells in PI and periodontitis, including sub-classification of T cells (CD4/8) as well as detection of cells that require multiple markers for identification (such as dendritic cells).

Retrospective Case-Control Study Genes Related to Bone Metabolism That Justify the Condition of Periodontal Disease and Failure of Dental Implants in Patients with down Syndrome.

Down syndrome patients show success rates in dental implants much lower than those observed in the general population. This retrospective case-control study aimed to identify possible genes that are related to the regulation of inflammatory responses and bone metabolism related to periimplantitis and implant loss, as well as genes related to bone quality. This process involved using the functional analysis of the gene expression software Transcriptome Analysis Console (TAC version 4.0 Applied BiosystemsTM, Thermo Fisher Scientific, Waltham, MA, USA) and a search for possible candidate genes involved. The focus was placed on the 93 genes related to periodontitis, periimplantitis, bone loss, implant loss, and genes related to bone quality and regulators underlying the establishment and maintenance of osseointegration. Five genes showed statistically significant results (p < 0.05) in our comparison. Four of them, IL1B (p = 0.023), IL1RN (p = 0.048), BGLAP (p = 0.0372) and PTK2 (p = 0.0075) were down-regulated in the periodontal disease and implant rejection group, and only one was overexpressed: FOXO1A (p = 0.0552). The genes with statistically significant alterations described in this article determine that the group of Down syndrome patients with periodontal disease and implant failure is a group of patients genetically susceptible to suffering from both conditions together.

Immunohistochemical analysis with apoptosis and autophagy markers in periodontitis and peri-implantitis: Clinical comparative study.

BACKGROUND AND OBJECTIVES: Recently, the terms autophagy and apoptosis have been studied on implants, especially in cell culture and in vitro studies, but in vivo evaluations are limited. The aim of this study was to compare the differences in apoptosis and autophagy intensity at the molecular and cellular level in periodontal and peri-implant diseases. METHODS: Sixty-four biopsy samples were obtained from 52 patients, 36 female and 16 male, whose mean age was between 18 and 75, and were included in the study. The periodontitis group was defined as PG (n:30 sample) and the peri-implantitis group as IG (n:34 samples). Granulation tissues as biopsy materials were collected, and immunohistochemical analysis was performed with hematoxylin-eosin, Masson's trichrome, anti-MAP1LC3A, anti-beclin, and anti-active caspase-3 antibodies and terminal TdT-mediated dUTP-biotin nick end labeling (TUNEL) methods. The histological slide images were evaluated with the ImageJ software program. Inflammatory cell density in epithelial tissue, inflammatory cell density in connective tissue, the density of necrotic tissue debris, and collagen density in connective tissue were scored between 0 and 3 (0: none, 1: minimal, 2: moderate, 3: severe by hematoxylin-eosin and Masson's trichrome). The antibody binding reaction areas were evaluated per unit area (mm2 ) in connective tissue by immunohistochemical examination. RESULTS: As histochemical evaluations, there was no statistically significant differences the mean inflammatory cell density value in the epithelial tissue, inflammatory cell density value in the connective tissue, density value of necrotic tissue debris, collagen density value in the connective tissue between the groups. There was no statistically significant difference on immunohistochemical staining with LC3, caspase-3, Beclin-1 and TUNEL between the two groups (p > .05). CONCLUSIONS: A higher rate of inflammatory accumulation was shown on peri-implantitis, but no difference was found between periodontitis and peri-implantitis according to autophagy and apoptosis markers. Studies with high sample sizes with different markers are needed.

Effects of Candidalysin Derived from Candida albicans on the Expression of Pro-Inflammatory Mediators in Human Gingival Fibroblasts.

Candida albicans (Ca) is frequently detected in the peri-implant sulcus with peri-implantitis, a major postoperative complication after oral implant therapy. However, the involvement of Ca in the pathogenesis of peri-implantitis remains unclear. In this study, we aimed to clarify Ca prevalence in the peri-implant sulcus and investigated the effects of candidalysin (Clys), a toxin produced by Ca, on human gingival fibroblasts (HGFs). Peri-implant crevicular fluid (PICF) was cultured using CHROMagar and Ca colonization rate and colony numbers were calculated. The levels of interleukin (IL)-1ß and soluble IL-6 receptor (sIL-6R) in PICF were quantified by enzyme-linked immunosorbent assay (ELISA). Pro-inflammatory mediator production and intracellular signaling pathway (MAPK) activation in HGFs were measured by ELISA and Western blotting, respectively. The Ca colonization rate and the average number of colonies in the peri-implantitis group tended to be higher than those in the healthy group. IL-1ß and sIL-6R levels in the PICF were significantly higher in the peri-implantitis group than in the healthy group. Clys significantly induced IL-6 and pro-matrix metalloproteinase (MMP)-1 productions in HGFs, and co-stimulation with Clys and sIL-6R increased IL-6, pro-MMP-1, and IL-8 production levels in HGFs compared with Clys stimulation alone. These findings suggest that Clys from Ca plays a role in the pathogenesis of peri-implantitis by inducing pro-inflammatory mediators.

Docosahexaenoic Acid-Loaded Nanostructured Lipid Carriers for the Treatment of Peri-Implantitis in Rats.

Being the most common cause of implant failure, peri-implantitis is defined as a pathological condition associated with the occurrence of peri-implant plaque, characterized by peri-implant mucosal inflammation and progressive loss of the supporting bone tissue attributed to the persistence of pro-inflammatory cytokines. Docosahexaenoic acid (DHA), which is a type of omega-3 polyunsaturated fatty acid, is generally used for the treatment of many inflammatory diseases. However, a suitable form for dosing and its therapeutic effect on peri-implantitis remain unclear. In this study, a novel nanostructured lipid carrier (NLC) loaded with squalene and DHA was fabricated (DHA-loaded NLC). The encapsulation efficiency and drug loading efficiency values of the DHA-loaded NLC were 78.13% ± 1.85% and 28.09% ± 0.48%, respectively. The release of DHA was gradual and steady until 144 h. In addition, the free-radical-scavenging rate of DHA-loaded NLC (0.57 ± 0.03) was much higher than that of sole DHA (0.17 ± 0.003). By inhibiting nuclear factor-κB p65 nuclear translocation, DHA-loaded NLC prevented the activation of nuclear factor-κB downstream inflammatory pathways and exerted anti-inflammatory effects on macrophages. Moreover, DHA-loaded NLC showed better effects on preventing alveolar bone resorption of rat peri-implantitis model than sole DHA. Hence, DHA-loaded NLC enhanced the anti-inflammatory bioavailability of DHA, offering a novel approach for the treatment of peri-implantitis.

Regulation of endothelial cells on the osteogenic ability of bone marrow mesenchymal stem cells in peri-implantitis.

OBJECTIVES: The relationship between bone resorption and angiogenesis in peri-implantitis remains to be studied. We constructed a Beagle dog model of peri-implantitis, and extracted bone marrow mesenchymal stem cells (BMSCs) and endothelial cells (ECs) for culture. The osteogenic ability of BMSCs in the presence of ECs was investigated through an in vitro osteogenic induction model, and its mechanism was initially explored. SUBJECTS AND METHODS: The peri-implantitis model was verified by ligation, bone loss was observed by micro-CT, and cytokines were detected by ELISA. The isolated BMSCs and ECs were cultured to detect the expression of angiogenesis, osteogenesis-related proteins, and NF-κB signaling pathway-related proteins. RESULTS: 8 weeks after surgery, the peri-implant gums were swollen, and micro-CT showed bone resorption. Compared with the control group, IL-1ß, TNF-α, ANGII and VEGF were markedly increased in the peri-implantitis group. In vitro studies found that the osteogenic differentiation ability of BMSCs co-cultured with IECs was decreased, and the expression of NF-κB signaling pathway-related cytokines was increased. CONCLUSION: Endothelial cells inhibit the osteogenic differentiation of bone marrow mesenchymal stem cells through NF-κB signaling in the environment of peri-implantitis, which may become a new target for the treatment of peri-implantitis.

Yth m6A RNA-Binding Protein 1 Regulates Osteogenesis of MC3T3-E1 Cells under Hypoxia via Translational Control of Thrombospondin-1.

Peri-implantitis is a major factor affecting implant prognosis, and the specific anatomy of the peri-implant area makes it more vulnerable to the local hypoxic environment caused by inflammation. N6-methyladenosine (m6A) plays a vital role in a multitude of biological processes, and its main "reader" Yth m6A RNA-binding protein 1 (YTHDF1) is suggested to affect osteogenic differentiation. However, the mechanism underlying the effect of YTHDF1 on osteogenic differentiation under hypoxic conditions remains unclear. To address this question, we examined the expression of YTHDF1 under hypoxia and observed that hypoxia suppressed osteogenic differentiation but promoted the expression of YTHDF1. Then we knocked down YTHDF1 and found decreased levels of osteogenic-related markers, alkaline phosphatase (ALP) activity, and alizarin red staining (ARS) under normoxia or hypoxia treatment. Bioinformatics analysis identified Thrombospondin-1 (THBS1) might be a downstream factor of YTHDF1. The results revealed that YTHDF1 enhanced the stability of THBS1 mRNA, and immunofluorescence assays found co-localization with YTHDF1 and THBS1 under hypoxia. Loss of function studies showed knocking down YTHDF1 or THBS1 exacerbated the osteogenic inhibition caused by hypoxia. All data imply that hypoxia suppresses osteogenic differentiation and promotes the expression of YTHDF1, which translationally regulates THBS1 in an m6A-dependent manner, potentially counteracting hypoxia-induced osteogenic inhibition through the YTHDF1/THBS1 pathway. The results of this study reveal for the first time the molecular mechanism of the regulation of osteogenic differentiation by YTHDF1 under hypoxia and suggest that YTHDF1, together with its downstream factor THBS1, may be critical targets to counteract osteogenic inhibition under hypoxic conditions, providing promising therapeutic strategy for the hypoxia-induced bone loss in peri-implantitis.

A GP130-Targeting Small Molecule, LMT-28, Reduces LPS-Induced Bone Resorption around Implants in Diabetic Models by Inhibiting IL-6/GP130/JAK2/STAT3 Signaling.

In this study, we examined the effect of the GP130-targeting molecule, LMT-28, on lipopolysaccharide- (LPS-) induced bone resorption around implants in diabetic models using in vitro and rat animal experiments. First, LMT-28 was added to osteoblasts stimulated by LPS and advanced glycation end products (AGEs), and nuclear factor-κB receptor-activating factor ligand (RANKL) and associated pathways were evaluated. Then, LMT-28 was administered by gavage at 0.23 mg/kg once every 5 days for 2 weeks to type 2 diabetic rats with peri-implantitis induced by LPS injection and silk ligature. The expression of IL-6 and RANKL was evaluated by immunohistochemistry, and the bone resorption around implants was evaluated by microcomputed tomography. The results showed that LMT-28 downregulated the expression of RANKL through the JAK2/STAT3 signaling pathway in osteoblasts stimulated by LPS and AGEs, reduced bone resorption around implants with peri-implantitis, decreased the expression of IL-6 and RANKL, and decreased osteoclast activity in type 2 diabetic rats. This study confirmed the ability of LMT-28 to reduce LPS-induced bone resorption around implants in diabetic rats.

Notch signalling cascade and proinflammatory mediators in peri-implant lesions with different RANKL/OPG ratios-An observational study.

BACKGROUND & OBJECTIVE: Notch signaling pathway has been linked to bone loss in periodontitis and peri-implantitis. This research aimed to determine the Notch signaling molecules expression levels (Notch1, Notch2, Jagged1, Hes1, and Hey1), along with bone remodeling mediators (RANKL and OPG) and proinflammatory cytokines (TNF-α, IL-17, IL-1ß, and IL-6) in patients with peri-implant diseases. The aforementioned markers' expression was evaluated in patients with different RANKL/OPG ratios. METHODS: Fifty patients with peri-implantitis (PI group) and 45 patients with peri-implant mucositis (PM group) were enrolled. Relative gene expression levels of investigated molecules were determined by reverse transcriptase-real-time polymerase chain reaction. On the basis of RANKL/OPG ratio, all peri-implant lesions were divided into subgroups: RANKL-predominant (RANKL > OPG) and OPG-predominant (RANKL < OPG). Clinical periodontal parameters (probing depth-PD, bleeding on probing-BOP, clinical attachment level-CAL and plaque index-PLI), were recorded for each patient around every tooth, and around placed implants (PDi, BOPi, CALi, PLIi). RESULTS: RANKL-predominant PM patients exhibited higher expression levels of Notch2 (p = .044) and Hey1 (p = .005) compared to OPG-predominant lesions. In all RANKL-predominant cases, Hey1 (p = .001), IL-1ß (p = .005), IL-6 (p = .002) were overexpressed in PI comparing to PM, accompanied with significantly higher PDi, CALi and PLIi in PI than PM (p = .001, p = .001 and p = .009). CONCLUSIONS: Notch2 upregulation in RANKL-predominant PM lesions could be an important contributor to alveolar bone resorption and represent a predictor of PM to PI transition. Similarly, the overexpression of IL-1ß and IL-6 might provide an osteoclastogenic environment in PI RANKL-predominant lesions.

Impact of peri-implantitis on the proteome biology of crevicular fluid: A pilot study.

BACKGROUND: The proteome of the peri-implant crevicular fluid (PICF) has not been systematically investigated. The aim of the present study was to reveal the proteome biology of dental implants affected with peri-implantitis. METHODS: Patients with at least one diseased implant were included (probing depth ≥6 mm, ≥3 mm peri-implant radiological bone loss). Using sterile paper strips, samples were collected from healthy implants (I), healthy teeth (T) and peri-implantitis affected implants (P). Proteome analysis was performed using liquid chromatography - tandem mass spectrometry (LC-MS/MS) and data independent acquisition, allowing the identification and quantification of human and bacterial proteins as well as semi-specific peptides. RESULTS: A total of 38 samples from 14 patients were included in the study; 2332 different human proteins were identified across all samples. No differentially expressed proteins between T and I were found. Comparing P to I, 59 proteins were found upregulated and 31 downregulated in P with significance. Upregulated proteins included proinflammatory proteins such as immunoglobulins, dysferlin, and S100P, as well as antimicrobial proteins, for example, myeloperoxidase or azurocidin. Gene ontology analysis further revealed higher activity of immunological pathways. Proteolytic patterns indicated the activity of inflammatory proteins such as cathepsin G. A total of 334 bacterial proteins were identified and quantified. Peri-implantitis showed elevated proteolytic activity. CONCLUSION: I and T share similarities in their proteome, while diseased implants deviate strongly from healthy conditions. The PICF proteome of peri-implantitis affected sites exhibits an inflammatory fingerprint, dominated by neutrophil activity when compared with healthy implants.

Immunopathological Inflammation in the Evolution of Mucositis and Peri-Implantitis.

The purpose of this study was to provide an immuno-mediated substantiation of the etiopathogenesis of mucositis and peri-implantitis based on the results of experimental, laboratory and clinical studies. The biopsy material was studied to identify impregnated nanoscale and microscale particles in the structure of pathological tissues by using X-ray microtomography and X-ray fluorescence analyses. Electron microscopy with energy-dispersive analysis identified the composition of supernatants containing nanoscale metal particles obtained from the surfaces of dental implants. The parameters of the nanoscale particles were determined by dynamic light scattering. Flow cytometry was used to study the effect of nanoscale particles on the ability to induce the activation and apoptosis of immunocompetent cells depending on the particles' concentrations during cultivation with the monocytic cell line THP-1 with the addition of inductors. An analysis of the laboratory results suggested the presence of dose-dependent activation, as well as early and late apoptosis of the immunocompetent cells. Activation and early and late apoptosis of a monocytic cell line when THP-1 was co-cultured with nanoscale metal particles in supernatants were shown for the first time. When human venous blood plasma was added, both activation and early and late apoptosis had a dose-dependent effect and differed from those of the control groups.