Jocelyn García-Sesnich

Host-Pathogen Interactions in Progressive Chronic Periodontitis

Periodontitis is an infection characterized by the occurrence of supporting tissue destruction with an episodic nature. Disease progression is often determined by the loss of attachment level or alveolar bone, and sequential probing of periodontal attachment remains the most commonly utilized method to diagnose progressive destruction of the periodontium. The tolerance method has been the most extensive clinical method used in recent years to determine site-specific attachment level changes. There is abundant evidence that major tissue destruction in periodontal lesions results from the recruitment of immune cells. Considerable effort has been made to study the host cell and mediator profiles involved in the pathogenesis of chronic periodontitis, but the definition of active sites, where current periodontal breakdown occurs, and consecutive characterization of the mediators involved are still among the main concerns. In the present review, we summarize periodontopathic bacteria and host factors, including infiltrating cell populations, cytokines, and host matrix metalloproteinases, associated with under-going episodic attachment loss that could partly explain the mechanisms involved in destruction of the supporting tissues of the tooth.

Host response mechanisms in periodontal diseases

Periodontal diseases usually refer to common inflammatory disorders known as gingivitis and periodontitis, which are caused by a pathogenic microbiota in the subgingival biofilm, including Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Tannerella forsythia and Treponema denticola that trigger innate, inflammatory, and adaptive immune responses. These processes result in the destruction of the tissues surrounding and supporting the teeth, and eventually in tissue, bone and finally, tooth loss. The innate immune response constitutes a homeostatic system, which is the first line of defense, and is able to recognize invading microorganisms as non-self, triggering immune responses to eliminate them. In addition to the innate immunity, adaptive immunity cells and characteristic cytokines have been described as important players in the periodontal disease pathogenesis scenario, with a special attention to CD4+ T-cells (T-helper cells). Interestingly, the T cell-mediated adaptive immunity development is highly dependent on innate immunity-associated antigen presenting cells, which after antigen capture undergo into a maturation process and migrate towards the lymph nodes, where they produce distinct patterns of cytokines that will contribute to the subsequent polarization and activation of specific T CD4+ lymphocytes. Skeletal homeostasis depends on a dynamic balance between the activities of the bone-forming osteoblasts (OBLs) and bone-resorbing osteoclasts (OCLs). This balance is tightly controlled by various regulatory systems, such as the endocrine system, and is influenced by the immune system, an osteoimmunological regulation depending on lymphocyte- and macrophage-derived cytokines. All these cytokines and inflammatory mediators are capable of acting alone or in concert, to stimulate periodontal breakdown and collagen destruction via tissue-derived matrix metalloproteinases, a characterization of the progression of periodontitis as a stage that presents a significantly host immune and inflammatory response to the microbial challenge that determine of susceptibility to develop the destructive/progressive periodontitis under the influence of multiple behavioral, environmental and genetic factors.

Interleukin-21 Expression and Its Association With Proinflammatory Cytokines in Untreated Chronic Periodontitis Patients

BACKGROUND Interleukin-21 (IL-21) controls the differentiation of T-helper Th17 cells and induces the production of IL-17 in this T-cell subtype. The aim of this study is to determine the relative expression of IL-21 in gingival tissues of chronic periodontitis patients and correlate/associate this expression with proinflammatory cytokines and clinical parameters of disease. METHODS Samples of gingival biopsies were collected from chronic periodontitis patients (n = 10) and controls (n = 8). The mRNA expressions of IL-21, IL-1β, IL-6, IL-17, IL-23, IL-10, and transforming growth factor-β1 (TGF-β1) were quantified using real-time reverse transcription-polymerase chain reaction. IL-21 levels were compared between chronic periodontitis and healthy gingival tissues and correlated with cytokine and clinical parameters of tissue destruction. RESULTS A significant overexpression of IL-21, IL-1β, IL-6, IL-17, and IL-23p19 was detected in periodontal disease-affected tissues compared to healthy gingival tissues. IL-10 and TGF-β1 were, however, downregulated in periodontal lesions. IL-21 yielded significant positive correlations with probing depth, clinical attachment level, IL-1β, and IL-6. In addition, IL-21 was negatively correlated with IL-10 and TGF-β1. CONCLUSIONS IL-21 was overexpressed in chronic periodontitis gingival tissues and correlated with clinical parameters of periodontal destruction and with proinflammatory cytokines. Therefore, IL-21 might play a role in the tissue destruction that characterizes chronic periodontal disease.

Pro-oxidant status and matrix metalloproteinases in apical lesions and gingival crevicular fluid as potential biomarkers for asymptomatic apical periodontitis and endodontic treatment response

BackgroundOxidative stress and matrix metalloproteinases -9 and -2 are involved in periodontal breakdown, whereas gingival crevicular fluid has been reported to reflect apical status. The aim of this study was to characterize oxidant balance and activity levels of MMP -2 and -9 in apical lesions and healthy periodontal ligament; and second, to determine whether potential changes in oxidant balance were reflected in gingival crevicular fluid from asymptomatic apical periodontitis (AAP)-affected teeth at baseline and after endodontic treatment.MethodsPatients with clinical diagnosis of AAP and healthy volunteers having indication of tooth extraction were recruited. Apical lesions and healthy periodontal ligaments, respectively, were homogenized or processed to obtain histological tissue sections. Matrix metalloproteinase -9 and -2 levels and/or activity were analyzed by Immunowestern blot, zymography and consecutive densitometric analysis, and their tissue localization was confirmed by immunohistochemistry. A second group of patients with AAP and indication of endodontic treatment was recruited. Gingival crevicular fluid was extracted from AAP-affected teeth at baseline, after endodontic treatment and healthy contralateral teeth. Total oxidant and antioxidant status were determined in homogenized tissue and GCF samples. Statistical analysis was performed using STATA v10 software with unpaired t test, Mann-Whitney test and Spearmans correlation.ResultsActivity of MMP-2 and MMP-9 along with oxidant status were higher in apical lesions (p < 0.05). Total oxidant status correlated positively with matrix metalloproteinase-2 and lesion size (p < 0.05). Gingival crevicular fluid showed significantly lower levels of total antioxidant status in diseased teeth at baseline compared to controls and endodontically-treated groups.ConclusionsApical lesions display an oxidant imbalance along with increased activity of matrix metalloproteinase-2 and -9 and might contribute to AAP progression. Oxidant imbalance can also be reflected in GCF from AAP-affected teeth and was restored to normal levels after conservative endodontic treatment. These mediators might be useful as potential biomarkers for chair-side complementary diagnostic of apical status in GCF.

Diagnostic accuracy for apical and chronic periodontitis biomarkers in gingival crevicular fluid: an exploratory study

AIM The aim of this study was to assess the levels and diagnostic accuracy of a set of potential biomarkers of periodontal tissue metabolism in gingival crevicular fluid (GCF) from patients with chronic periodontitis (CP) and asymptomatic apical periodontitis ( AAP). MATERIALS AND METHODS Thirty one GCF samples from 11 CP patients, 44 GCF samples from 38 AAP patients and 31 GCF samples from 13 healthy volunteers were obtained (N = 106). Matrix metalloproteinases (MMPs) -2 and -9 were determined by zymography; levels of MMP-8 by ELISA and IFMA and MPO by ELISA. IL-1, IL-6, TNFα, DKK-1, Osteonectin, Periostin, TRAP-5 and OPG were determined by a multiplex quantitative panel. Statistical analysis was performed using linear mixed-effects models. RESULTS The MMP-9 and MMP-8 were higher in CP, followed by AAP, versus healthy individuals (p < 0.05). ProMMP-2, MPO, IL-1, IL-6, PTN, TRAP-5 and OPG were significantly higher in CP when compared with AAP and healthy patients (p < 0.05). The highest diagnostic accuracies were observed for ProMMP-2, ProMMP-9, MMP-8 and TRAP-5 (AUC > 0.97) in CP, and for the active form of MMP-9 and MMP-8 (AUC > 0.90) in AAP. CONCLUSION Gingival crevicular fluid composition is modified by CP and AAP. MMP-9 and MMP-8 show diagnostic potential for CP and AAP, whereas MMP-2 and TRAP-5 are useful only for CP.

Levels of interleukin-21 in patients with untreated chronic periodontitis.

BACKGROUND A growing body of evidence suggested that interleukin (IL)-21 enhances the effector phase during T-cell responses. The aim of our study is to determine the levels of IL-21 in periodontal sites from patients with chronic periodontitis and controls. METHODS The population studied consisted of 34 patients (15 with chronic periodontitis and 19 healthy patients). Twenty samples (10 gingival crevicular fluid [GCF] and 10 gingival biopsies) were collected from each group before the patients with periodontitis received periodontal treatment. Total protein concentrations were measured in all samples; the presence of IL-21 was confirmed by immunohistochemistry and Western blot, and IL-21 levels were quantified through an enzyme-linked immunosorbent assay. Statistical analyses were performed using statistical software. Data were expressed as patient means ± SDs or medians (interquartile ranges) by using the χ(2), Student t, and Mann-Whitney U tests. RESULTS GCF IL-21 was mainly detected in patients with chronic periodontitis (P <0.05). Levels of IL-21 in gingival tissues were significantly higher in patients with chronic periodontitis compared to healthy individuals (P <0.05). The Western blot and immunohistochemical staining confirmed the presence of IL-21 in periodontal tissues and GCF. CONCLUSION IL-21 was highly expressed in patients with chronic periodontitis, especially in gingival biopsies; therefore, IL-21 might play a role in the T-cell response.

Clinical Effects of Lactobacillus rhamnosus in Non-Surgical Treatment of Chronic Periodontitis: A Randomized Placebo-Controlled Trial With 1-Year Follow-Up

BACKGROUND Probiotics are living microorganisms that provide beneficial effects for the host when administered in proper quantities. The aim of this double-masked placebo-controlled parallel-arm randomized clinical trial is to evaluate the clinical effects of a Lactobacillus rhamnosus SP1-containing probiotic sachet as an adjunct to non-surgical therapy. METHODS Twenty-eight systemically healthy volunteers with chronic periodontitis were recruited and monitored clinically at baseline and 3, 6, 9, and 12 months after therapy. Clinical parameters measured included plaque accumulation, bleeding on probing, probing depths (PDs), and clinical attachment loss. Patients received non-surgical therapy, including scaling and root planing (SRP), and were assigned randomly to a test (SRP + probiotic, n = 14) or control (SRP + placebo, n = 14) group. The intake, once a day for 3 months, of an L. rhamnosus SP1 probiotic sachet commenced after the last session of SRP. RESULTS Both test and control groups showed improvements in clinical parameters at all time points evaluated. However, the test group showed greater reductions in PD than the control. Also, at initial visits and after 1-year follow-up, the test group showed a statistically significant reduction in the number of participants with PD ≥6 mm, indicating a reduced need for surgery, in contrast to the placebo group. CONCLUSION The results of this trial indicate that oral administration of L. rhamnosus SP1 resulted in similar clinical improvements compared with SRP alone.

Matrix metalloproteinases regulate extracellular levels of SDF-1/CXCL12, IL-6 and VEGF in hydrogen peroxide-stimulated human periodontal ligament fibroblasts

Periodontitis is a highly prevalent infectious disease characterized by the progressive inflammatory destruction of tooth-supporting structures, leading to tooth loss. The underling molecular mechanisms of the disease are incompletely understood, precluding the development of more efficient screening, diagnostic and therapeutic approaches. We investigated the interrelation of three known effector mechanisms of the cellular response to periodontal infection, namely reactive oxygen species (ROS), matrix metalloproteinases (MMPs) and cytokines in primary cell cultures of human periodontal ligament fibroblast (hPDLF). We demonstrated that ROS increase the activity/levels of gelatinolytic MMPs, and stimulate cytokine secretion in hPDLF. Additionally, we proved that MMPs possesses immune modulatory capacity, regulating the secreted levels of cytokines in ROS-stimulated hPDLF cultures. This evidence provides further insight in the molecular pathogenesis of periodontitis, contributing to the future development of more effective therapies.

High levels of CXC Ligand 12/stromal cell-derived factor 1 in apical lesions of endodontic origin associated with mast cell infiltration

INTRODUCTION CXC ligand 12/stromal-derived factor-1 (CXCL12/SDF-1) is a pleiotropic chemokine that regulates the influx of a wide range of leukocytes. The aim of this study was to characterize CXCL12/SDF-1 in apical lesions (ALs) of endodontic origin, with special emphasis in associated immune cell populations. METHODS In this case-control study, 29 individuals with chronic apical periodontitis and 21 healthy volunteers were enrolled. ALs and healthy periodontal ligament samples were obtained for tissue homogenization, immune Western blotting, and enzyme-linked immunosorbent assay to determine CXCL12/SDF-1 forms and levels. Anatomopathologic diagnosis, immunostaining for CXCL12/SDF-1, CD117-CXCL12/SDF-1, and toluidine blue were also performed to identify tissue and cell localization. Finally, a set of tissue samples were digested and analyzed by flow cytometry to identify CXCL12/SDF-1 in different immune cell populations. Data were analyzed with Stata v11 and WinDi 2.9 software, and significance was considered if P < .05. RESULTS CXCL12/SDF-1 was predominantly identified as monomers; levels of CXCL12/SDF-1 were significantly higher in ALs compared with controls, and it was primarily localized to inflammatory infiltrates. Expression of CXCL12/SDF-1 was colocalized to mast cells in tissue sections. Furthermore, CD117(+) mast cells were the second most frequent infiltrating cells and the main CXCL12/SDF-1 expressing cells, followed by CD4(+) lymphocytes, monocytes/macrophages, neutrophils, and dendritic cells. CONCLUSIONS ALs of endodontic origin demonstrated higher levels of CXCL12/SDF-1 compared with controls. CXCL12/SDF-1 was identified in immune cell populations, whereas mast cells represented the major CXCL12/SDF-1 expressing cells, suggesting that this chemokine might play a central role in apical tissue destruction, most probably inducing persistent recruitment of immune cells, particularly of mast cells.

Asociación entre niveles de TNF-α en fluido crevicular gingival de dientes con periodontitis apical asintomática

Resumen es: Como consecuencia de necrosis pulpar septica, el ingreso de productos bacterianos en el periapice induce la produccion de citoquinas pro-inflamatorias co...