Análise da imunoexpressão da esclerostina em lesões fibro-ósseas dos maxilares

Abstract

Sclerostin, a product of the SOST gene, acts as a negative regulator of bone formation, primarily because of its properties of inhibition of some signaling pathways related to bone remodeling. The sclerostin is mainly secreted by osteocytes, but also, by other cell populations. The aim of the study was to assess the sclerostin expression in Benign Fibro‑Osseous Lesions (BFOL) of the jaws. A retrospective, transversal, unicenter study selected the cases diagnosed as BFOL. The selected cases were retrieved, and the paraffin blocks were assessed for histological slides to be submitted for a) histochemistry by Hematoxylin and Eosin stain; b) immunohistochemistry for sclerostin expression. For the control group, 6 cases of normal bone harvested from healthy individuals were selected. A total of 66 histological slides from 40 biopsies of 32 patients were analyzed, 20 lesions in females (62.5%) and 12 lesions (37.5%) in male individuals. Eighteen cases were classified as BFOL based only on the anatomical analysis, and the other cases were classified by both clinical and pathological diagnosis, as follows: 06 cases of Fibrous Dysplasia; 4 cases of Juvenile trabecular ossifying fibroma; 2 cases of Psammomatoid ossifying fibroma; and 2 cases of Cemento-osseous dysplasia. There was a positive sclerostin expression in 21 biopsies (52.5%). The marked cells were more present in the fibrous tissue than in the bone. In the cases with positivity in the osteocytes, only 2 were revealed to be in the intralesional bone, and in the other cases, the positivity was found to be in the osteocytes within the perilesional bone. At the fibrous component, marked cells revealed a phenotype similar to the mast cells, and the sclerostin-positive cells were majorly close to the vascular spaces. In the control group, it was found that sclerostin was expressed in cells both at the medullary spaces and in a few osteocytes. In conclusion, Benign Fibro‑Osseous Lesions can express sclerostin, and this expression is mostly concentrated in the fibrous tissue, in mast cell-like cells. In addition, sclerostin is also expressed in the intralesional bone in some specific cases, and on the lesion-surrounding bone.