Endothelial cells of oral pyogenic granulomas express eNOS and CD105/endoglin: an immunohistochemical study

Abstract

The pyogenic granuloma (PG) is a common localized hyperplastic lesion of the oral cavity. The purpose of the present study was to investigate the immunohistochemical expression of endothelial nitric oxide synthases (eNOS) and CD105/endoglin in oral PGs, to evaluate their involvement in the angiogenetic pathways of the lesion. Ninety-three PGs were included in the study. Sixteen tumors were further sub-classified as pregnancy tumors (PT) and seventeen as pyogenic granulomas with fibrosis (PGFM). Immunohistochemical expression of eNOS and CD105/endoglin was quantified by computerized image analysis with a semi-automated system. Percentage of staining and number of objects (positive vessels) were recorded for each case. Intense eNOS expression was seen in 92 of 93 lesions. A statistically significant association was found between eNOS percentage of staining/eNOS positive vascular spaces (objects) and age of the patients (9% increase per decade of life). Approximately 40% less eNOS positive objects were recorded in PGFM compared with PGs. Intense membranous CD105/endoglin expression was seen in all cases. The percentage of CD105/endoglin staining was statistically increased in PGs compared with PT. Approximately 40% less CD105/endoglin objects were found in PGFM compared with PGs; 56% more CD105/endoglin objects were found in tongue lesions, compared with gingival lesions. There was no statistically significant correlation considering percentage of staining and number of objects between CD105/endoglin and eNOS. It is suggested that eNOS and CD105/endoglin are involved in the angiogenetic pathways of PG.