Immunohistochemical expression of TGF-ß1 and MMP-9 in periapical lesions

Abstract The objective of this study was to evaluate the expression of matrix metalloproteinase 9 (MMP-9) and transforming growth factor beta (TGF-β1) in periapical lesion samples correlated with the intensity of the inflammatory infiltrate and thickness of the epithelial lining. Forty-five cases of periapical lesions (23 periapical granulomas and 22 radicular cysts) were subjected to morphological and immunohistochemical analyses using anti-MMP-9 and anti-TGF-β1 antibodies. The data were analyzed using the following tests: non-parametric Mann-Whitney, chi-square, Fisher's exact test and Spearman's correlation test (P<0.05). Analysis of inflammatory infiltrate revealed that 78% of periapical granulomas presented infiltrate grade III, in contrast with 32% of radicular cysts (P<0.001). Morphological evaluation of the epithelial thickness in radicular cysts revealed the presence of atrophic epithelium in 86% of the cysts. The immunostaining of MMP-9 was score 2 in 67% of the granulomas and 77% of the cysts. Both lesions were predominantly score 1 for TGF-β1. Significant differences were confirmed between the expression scores of TGF-β1 and MMP-9 in periapical granulomas (p = 0.004) and in radicular cysts (p < 0.001). Expression of TGF-β1 was different for periapical granulomas and radicular cysts. This immunoregulatory cytokine seems more representative in asymptomatic lesions. The extracellular matrix remodeling process dependent on MMP-9 seems to be similar for both periapical granulomas and radicular cysts. TGF-β1 and MMP-9 may play an important role in the maintenance of periapical lesions.

Analysis of Interleukin 17A in periapical abscess and granuloma lesions

Abstract Interleukin 17A (IL-17A) is a proinflammatory cytokine responsible for the initiation and propagation of inflammation. One of its actions is the recruitment of neutrophils to the site of infection. The aim of this study was to investigate whether there is association between IL-17A expression and neutrophil infiltration in periapical abscesses and periapical granulomas, as well as to find which type of T lymphocyte effector (CD4+ or CD8+) expresses IL-17A in these lesions. Elastase, CD4, CD8, and IL-17A were analyzed by immunohistochemistry and immunofluorescence, in the biopsies of periapical lesions. Abscess lesions exhibited the highest labeling area for IL-17A (p = 0.011). During double immunofluorescence staining, there were significantly more CD4+/IL-17A+ cells compared to CD8+/IL-17A+ cells, both in the abscesses (p = 0.025) and granulomas (p = 0.011). In conclusion, IL-17A was intensively expressed in periapical abscesses rich in neutrophils. The high percentage of IL-17A in these cases suggests the participation of this cytokine particularly in the acute stages of the inflammatory process of the periapical lesions.

Stem cells and androgen receptor in human periapical periodontitis / Células madre y receptor de andrógenos en periodontitis periapical humana

Activation of macrophages in periapical granulomas occurs through the presence of cytokines, endotoxin and other genetic and epigenetic factors, allowing the initiation of inflammation and bone resorption. The present study aims to analyze the presence of CD133 protein (marker of stem cells) and the AR (androgen receptor) protein in biopsies of human odontogenic periapical granuloma. Biopsies from 14 adult male patients with diagnosis of periapical granuloma included in paraffin blocks were processed histologically to obtain 5-um thick sections. Protein presence was detected and analyzed by immunohistochemistry of CD133 and AR. The quantification considered the number of positive cells in 0.17 mm2 random areas under the microscope using a 1000X objective. Both CD133 and AR proteins are expressed abundantly in cells in pathological periapical granulomas tissue. The number of cells expressing CD133 and AR shows a wide variation coefficient, so its variation is a particular feature for each individual. We concluded that in human odontogenic periapical granuloma there are abundant stem cells and cells expressing AR that may be important for the pathogenic inflammatory process.

La activación de los macrófagos en los granulomas periapicales humanos se producen a través de la presencia de citoquinas, endotoxinas y otros factores genéticos y epigenéticos que permiten la iniciación de la inflamación y la reabsorción ósea. El presente estudio pretende analizar la presencia de proteína CD133 (marcador de células madre) y de la proteína RA (receptor de andrógenos) en las biopsias de granulomas periapicales odontogénicos humanos. Las biopsias de 14 pacientes varones adultos con diagnóstico de granuloma periapical fueron incluidos en bloques de parafina y se procesaron histológicamente para obtener secciones de 5 micras de espesor. La presencia de CD133 y RA fueron detectadas y analizadas por inmunohistoquímica. La cuantificación se realizó considerando el número de células positivas en áreas al azar de 0,17mm2, utilizando microscopio con objetivo de 1000X. Ambas proteínas, CD133 y RA se expresan en abundancia en las células del tejido patológico con granuloma periapical. El número de células que expresan CD133 y RA presentan un amplio coeficiente de variación, por lo que su variación es una característica particular de cada individuo. Se concluye que en granuloma periapical odontogénico humano se expresan abundantes células madre y proteínas receptoras de andrógenos, antecedentes que pueden sermuy importantes en la expresión y diagnosis de los procesos patológicos inflamatorios.