Presence of markers of activation pathways of macrophages in chronic periodontitis

Indexación: Web of Science; ScieloLa periodontitis crónica es una patología infecciosa, causada por un complejo de especies bacterianas, que afecta principalmente los tejidos de inserción de los dientes. La respuesta inmune-inflamatoria producida se caracteriza por la presencia de un infiltrado inflamatorio, en el cual los macrófagos representan entre 5 al 30%. Es sabido que los macrófagos se activan mediante dos vías: Clásica y Alterna, caracterizadas por la presencia de marcadores indirectos: IFN-γ e IL-6 para la vía clásica e IL-4 para la vía alterna, ampliamente abordados. Recientemente, se ha descrito a la subunidad A del factor XIII de la coagulación (FXIII-A) como un buen marcador de la vía alterna. El objetivo de este estudio consiste en determinar la presencia de IFN-γ, IL-6, FXIII-A e IL-4 como marcadores de las vías de activación de los macrófagos, en pacientes con periodontitis crónica. Para tal efecto, se realizó inmunohistoquímica y Western-Blot para los cuatro marcadores junto a CD-68, marcador de macrófagos, en 18 biopsias de tejido periodontal sano y 18 con periodontitis crónica. Se detectó la presencia de IFN-γ, IL-6, IL-4 y FXIII-A junto a CD68+, en todas las muestras de pacientes sanos y con periodontitis. Los resultados obtenidos sugieren que al estar presente IFN-γ, IL-6, IL-4 y FXIII-A, los macrófagos se activarían a través de ambas vías, lo cual, produciría una respuesta tanto proinflamatoria (Th1) como antinflamatoria (Th2). Son necesarios más estudios para determinar si existe una vía preferencial de activación.Periodontitis is a chronic infectious disease caused by a bacterial species complex, which affects mainly the insertion tissues of the teeth. The immune-inflammatory response produced is characterized by an inflammatory infiltrate in which macrophages represent between 5 to 30%. It is known and has been widely discussed that macrophages are activated in two ways: Classical and Alterna, characterized by the presence of indirect markers: IFN-γ and IL-6 for the classical pathway and IL-4 for the alternative pathway. Recently the subunit A of the clotting factor XIII (FXIII-A) has been described as a good marker of the alternative pathway. The objective of this study is to determine the presence of IFN-γ, IL-6, IL-4 and FXIII-A as markers of the macrophage activation pathways in patients with chronic periodontitis. To this end, we performed immunohistochemistry and Western blot for the four markers with CD68 macrophage marker, in 18 healthy periodontal tissue biopsies and 18 with chronic periodontitis. We detected the presence of IFN-γ, IL-6, IL-4 and FXIII-A with CD68 +, in all samples of healthy patients and periodontitis. The results suggest that when present, IFN-γ, IL-6, IL-4 and FXIII-A, activate macrophages through both routes, which would produce a proinflammatory response (Th1) as antiinflammatory (Th2). Further studies are necessary to determine whether there is a preferential pathway activation.http://www.scielo.cl/pdf/piro/v5n3/art06.pd

Variabilidad de la Respuesta de las Células Dendríticas Estimuladas in vitro con Porphyromonas gingivalis y Aggregatibacter actinomycetemcomitans

ResumenLas células dendríticas son células presentadoras de antígeno capaces de inducir la activación y maduración de linfocitos T CD4+ vírgenes hacia un fenotipo efector especifico Th1 o Th2, dependiendo del tipo de antigeno presentado, las senales co-estimuladoras que expresan y el ambiente de citoquinas en el cual se produce la interaccion celula-celula. El objetivo del presente trabajo es analizar la respuesta de las celulas dendriticas estimuladas in vitro con distintas concentraciones de las bacterias periodontopatógenas Pg y Aa. En celulas dendriticas derivadas de monocitos de sangre periferica estimuladas con 101 a 109 bacterias/mL de Pg y Aa se evaluo la expresion del marcador de maduracion CD80 mediante citometria de flujo y de las citoquinas IL1β, IL2, IL5, IL6, IL10, IL12, IL13, IFNγ, TNFα y TNFβ mediante RT-PCR cuantitativa. Aa y Pg indujeron maduracion de las celulas dendriticas, detectandose significativamente mayor expresion de CD80 con la estimulacion de Aa, e indujeron predominantemente la expresion de citoquinas propias de una respuesta Th1. Dependiendo de la carga bacteriana, fueron detectados distintos umbrales de induccion de expresion de citoquinas. Aa indujo la sintesis de IL1β, IL12, IFNγ, TNFα y TNFβ a menor carga bacteriana que Pg. Tomados en conjunto, estos datos nos permiten especular un mayor potencial antigenico y proyectar una mayor capacidad patogenica durante la infeccion periodontal de Aa en comparación a Pg.AbstractDendritic cells are potent antigen-presenting cells able to prime naive T cells and polarize them towards a Th1 or Th2 response, depending on the type of the antigen presented to the TCR, the type of costimulatory signals, and the cytokine pattern in the environment. The aim of this work was to analyze the response of dendritic cells to in vitro stimulation with Pg and Aa. In monocyte-derived dendritic cells stimulated with 101 to 109 bacteria/mL of Pg or Aa were evaluated both the expression of the maturation marker CD80 by flow cytometry and the expression of the cytokines IL1β, IL2, IL5, IL6, IL10, IL12, IL13, IFNγ, TNFα and TNFβ by quantitative RT-PCR. Both Pg and Aa led to dendritic cell maturation, detecting higher CD80 expression upon Aa-stimulation, and induced a Th1 pattern of cytokine expression. Aa-stimulated dendritic cells expressed IL1β, IL12, IFNγ, TNFα and TNFβ mRNAs with lower bacterial charge than with Pg. Furthermore, our data indicated the existence of distinct thresholds for the induction of the different cytokines analyzed. Taken together, these data allow us to speculate a higher antigenic potential and higher pathogenic capacity of Aa than Pg during periodontal infections

Presencia de Linfocitos T Reguladores en Periodontitis Crónica

ResumenLa enfermedad periodontal requiere de un hospedero susceptible para su desarrollo y progresión. Dentro de las características del hospedero se encuentra la respuesta T reguladora, que otorga tolerancia frente a antígenos propios y participa durante las enfermedades infecciosas limitando el daño tisular, sin disminuir la respuesta antibacteriana. El presente estudio tiene por objetivo determinar la presencia, reclutamiento y función de Tregs en pacientes con periodontitis crónica. En 10 biopsias de tejido periodontal sano y con periodontits crónica se realizó inmunohistoquímica para marcadores (CD4, CD25, Foxp3), quimioquinas (CCL17, CCL22) y citoquinas (TGF-β, IL-10) de Tregs. Además de Western-Blot para detectar las citoquinas. Los resultados obtenidos sugieren una posible asociación entre células Tregs y la infección periodontal, ya que se confirma su reclutamiento y presencia. Sin embargo, son necesarios más estudios del posible desbalance con su contraparte pro-inflamatoria Th17, que expliquen en parte la compleja etiopatogenia de la enfermedad periodontal.AbstractPeriodontal disease requires a susceptible host to initiation, development and progression. T regulatory response is one of these inmunoregulatory characteristics of the susceptible host, which provide tolerance, tissular protection during infection without impairing the control of periodontopathogens. The aim of this study is to determinate the presence, homing and function of T regulatory cells (Tregs) in patients with chronic periodontitis. Ten biopsies were taken from pockets, the presence of Tregs markers (CD4, CD25, Foxp3), chemokines (CCL17, CCL22) and cytokines (TGF-β, IL-10) were determinate by immunohistochemistry. Cytokines also were detected with Western-Blot. Our results suggest a possible association between Tregs and periodontal infection, confirming homing and presence of Tregs. However, further studies are required to determine the possible imbalance with pro-inflammatory part Th17, that might explain the complex etiopathogenesis of periodontal disease

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

Cytokine Gene Expression Profiles during Initiation, Progression and Resolution of Periodontitis

AIM: Variations in the expression of cytokines during the progression of periodontitis remain ill-defined. We evaluated the expression of 19 cytokine genes related to T-cell phenotype/function during initiation, progression and resolution of periodontitis, and related these to the expression of soft and bone tissue destruction genes (TDGs). MATERIALS AND METHODS: A ligature-induced periodontitis model was used in rhesus monkeys (M. mulatta) (n = 18). Gingival tissues were taken at baseline pre-ligation, 2 weeks and 1 month (Initiation) and 3 months (progression) post ligation. Ligatures were removed and samples taken 2 months later (resolution). Total RNA was isolated and the Rhesus Gene 1.0 ST (Affymetrix) used for gene expression analysis. Significant expression changes were validated by qRT-PCR. RESULTS: Disease initiation/progression was characterized by overexpression of Th17/Treg cytokine genes (IL-1β, IL-6, TGFβ and IL-21) and down-regulation of Th1/Th2 cytokine genes (IL-18 and IL-25). Increased IL-2 and decreased IL-10 levels were seen during disease resolution. Several Th17/Treg cytokine genes positively correlated with TDGs, whereas most Th1/Th2 genes exhibited a negative correlation. CONCLUSION: Initiation, progression and resolution of periodontitis involve over- and underexpression of cytokine genes related to various T-helper subsets. In addition, variations in individual T-helper response subset/genes during disease progression correlated with protective/destructive outcomes

Osteoimmunology of Oral and Maxillofacial Diseases : Translational Applications Based on Biological Mechanisms

The maxillofacial skeleton is highly dynamic and requires a constant equilibrium between the bone resorption and bone formation. The field of osteoimmunology explores the interactions between bone metabolism and the immune response, providing a context to study the complex cellular and molecular networks involved in oro-maxillofacial osteolytic diseases. In this review, we present a framework for understanding the potential mechanisms underlying the immuno-pathobiology in etiologically-diverse diseases that affect the oral and maxillofacial region and share bone destruction as their common clinical outcome. These otherwise different pathologies share similar inflammatory pathways mediated by central cellular players, such as macrophages, T and B cells, that promote the differentiation and activation of osteoclasts, ineffective or insufficient bone apposition by osteoblasts, and the continuous production of osteoclastogenic signals by immune and local stromal cells. We also present the potential translational applications of this knowledge based on the biological mechanisms involved in the inflammation-induced bone destruction. Such applications can be the development of immune-based therapies that promote bone healing/regeneration, the identification of host-derived inflammatory/collagenolytic biomarkers as diagnostics tools, the assessment of links between oral and systemic diseases; and the characterization of genetic polymorphisms in immune or bone-related genes that will help diagnosis of susceptible individuals.Peer reviewe