Neuroendocrine cells in Malassez epithelium and gingiva of the cat

Abstract

Malassez epithelium has been designated as epithelial cell rests, the biological significance of which is still under debate. This study was designed to analyze Malassez epithelium for the presence of neuroendocrine cells. Gingival tissue was included as a positive control. Using immunohistochemistry, confocal and light microscopy, Malassez epithelium and gingival epithelium from mature cats (n = 5) were examined for cells containing the neuropeptides calcitonin gene-related peptide (CGRP), substance P (SP), and vasoactive intestinal peptide (VIP). Both Malassez epithelium and the basal epithelial cell layers in gingival rete pegs regularly displayed cells immunoreactive to CGRP, SP, and VIP. The immunopositive cells were most frequently present in the epithelial cell clusters and strands of Malassez located in the cervical half of thc periodontal ligament. Double immunolabeling revealed cellular co-expression of CGRP or SP with VIP, and the neuropeptides were co-localized in the cellular compartments. Labeled cells in both epithelia were occasionally supported by immunoreactive nerve fibers. This study shows that cells immunoreactive to CGRP, SP, and VIP arc located within the cat Malassez epithelium. The localization of neuroendocrine cells verifies the diversity of this epithelium and confirms that Malassez epithelium is composed of different cell types, in common with epithelia from other locations. The presence of neuroendocrine cells in Malassez epithelium strongly suggests biological functions of this tissue, and the neuropeptide content may thus indicate endocrine functions of the cells.

Epithelial Cell Rests of Malassez and OX6‐Immunopositive Cells in the Periodontal Ligament of Rat Molars: A Light and Transmission Electron Microscope Study

“…Immunohistochemical and immunoelectron microscopic analyses have verified the presence and colocalization of several neuropeptides in single cells of ERM clusters (Kvinnsland et al, 2000;Tadokoro et al, 2002Tadokoro et al, , 2003. In addition to neuroendocrine cells, immunocompetent cells have also been confirmed in the vicinity of the ERM in rat PDL induced by mechanical, orthodontic force (Vandevska-Radunovic et al, 1997).…”

Distribution of Epithelial Cells and Their Relationship to Immunocompetent Cells in Rat Molars: A Confocal and Transmission Electron Microscope Study

“…It has recently been reported that ERM express hard-tissue-related proteins such as enamel and bone morphogenetic proteins during cementum repair (Hasegawa et al 2003). It has also been demonstrated that periodontal nerve endings and ERM have a close relationship (Lambrichts et al 1993;Kvinnsland et al 2000;Tadokoro et al 2002Tadokoro et al ,2003 and that an interaction between PDLderived epithelial cells and fibroblasts regulates the expression of alkaline phosphatase, osteocalcin, and bone sialoprotein (Shimonishi et al 2005(Shimonishi et al ,2008. These reports suggest that ERM function not independently, but through interaction with other cells or in response to extrinsic stimuli.…”

The human periodontal membrane – focusing on the spatial interrelation between the epithelial layer of Malassez, fibers, and innervation

“…The present study showed that the epithelial layer of Malassez seemingly divides areas rich in innervation from areas with only sparse innervation. Kvinnsland et al [19] found neuro-endocrine cells in the Malassez epithelium in the rat. In the present study, it was difficult to locate nerve fibers specifically in the epithelial layer of Malassez.…”