Immunohistochemical Localization of LIM Mineralization Protein 1 in Pulp-Dentin Complex of Human Teeth with Normal and Pathologic Conditions

LIM mineralization protein 1 (LMP-1) is an essential positive regulator of osteoblast differentiation and maturation and bone formation. However, the expression and distribution of LMP-1 in human teeth are largely unknown. The aim of this study was to detect the expression of LMP-1 in normal healthy human teeth and human teeth with various pathologic conditions. LMP-1 expression was determined by immunohistochemistry in all of the samples including 12 healthy teeth, 10 teeth with caries, 12 teeth with pulpitis, and 4 teeth with pulp calcification. We found that LMP-1 was expressed primarily in predentin, odontoblasts, and endothelial cells of the blood vessels of healthy teeth. In addition, LMP-1 expression was also found in unmineralized reparative dentin, odontoblast-like cells, and pulp fibroblasts in teeth with caries and pulpitis. Furthermore, we found LMP-1 expression on the surface of the pulp stone or in the residual predentin of teeth with pulp calcification. Our data suggest that LMP-1 plays a role in odontoblast differentiation and dentin matrix mineralization of human teeth with normal and pathologic conditions.