An Immunohistochemistry Study of Cementum Protein CEMP1 Expression in Normal Human Tissues

Objectives: CEMP1 is a protein express normally in radicular cementum, it has been characterized as a protein participating in the biomineralization of progenitor cells in the periodontal ligament, and it is frequently used as a marker for cementoblastic lineage. At present, no histological data is available to indicate its expression and distribution pattern in other human tissues.The purpose of this study was to investigate the spacial expression pattern and significance of CEMP1 in normal human tissues.
Methods: Immunohistochemical examination of CEMP1 was conducted in 13 different human tissues, from legalized autopsies. The study was approved by the ISSEMyM-COE ethics committee. Two different antibodies for CEMP1 were used with the streptavidin-biotin complex method following relevant antigen retrieval techniques according to standard protocols. Positive reactivity was defined as the presence of yellow-brown stained cell cytoplasm.
Results: Most normal tissues showed weak to moderate cytoplasmatic positivity for CEMP1. Strong staining was observed in salivary glands, endothelial cells and in exocrine pancreas. Also, CEMP1 showed moderate to strong cytoplasmatic expression in the smooth muscle, kidney, lung, small intestine, and colon. However, the bile ducts, pancreatic islets, and spleen were negative for CEMP1. The pattern of staining was the same for the two antibodies.
Conclusions: In the present study we analyzed CEMP1 expression and distribution in normal tissue samples using immunohistochemistry. CEMP1 is express in normal human tissues and while its physiological role is unknown, the results revealed that CEMP1 expression is majorly distributed in epithelial cells. The present study provides first histological evidence of CEMP1 expression in human tissues different from cementum. We suggest to examine the expression and action of CEMP1 protein in normal and pathological conditions. (Research supported by DGAPA-UNAM, PAPIIT IA201214).