Expression of calcitonin gene-related peptide (CGRP) in irreversible acute pulpitis

The main goal of this study was to evaluate tissue levels of calcitonin gene-related peptide (CGRP) in human pulpal samples collected from teeth with a clinical diagnosis of acute irreversible pulpitis, normal pulps, and teeth with induced pulpal inflammation. All the pulp tissue was mechanically separated, collagenase digested to release individual cells, and labeled with FITC detection of an anti-CGRP polyclonal antibody. Detection of CGRP was possible in these cells due to a binding of the antibody to CGRP that was itself bound to its cell surface receptor. Flow cytometry analysis indicated that the labeled pulp cells were located in a region of low size and complexity according to their forward (FSC) and side scatter (SSC) properties. Significant statistical differences were found between the percentages of CGRP expression in healthy pulps and pulps with induced inflammation and between healthy pulps and pulps with acute irreversible pulpitis. No significant statistical differences were found between pulps with induced inflammation and pulps with acute irreversible pulpitis. These findings support the hypothesis that the CGRP system is active in human pulpal inflammation and may modulate the inflammatory response.