neuropeptide-y and Dental-Caries

To investigate whether dental pulp fibroblasts express neuropeptide Y (NPY) and NPY-Y1 in vitro and to determine the effects of the cytokines including interleukin-1β (IL-1β), TGF- β(1) , substance P and NPY on the expression of NPY Y1.. Three primary fibroblast cell strains were obtained from freshly extracted human third molar teeth. RT-PCR was utilized to detect expression of NPY and mRNA expression. Membrane protein samples were isolated, and protein expression was determined by Western blotting. Radioimmunoassay was used to quantify NPY expression in healthy (n = 35) and carious (n = 39) whole pulp samples, and the student's t-test was used to test for statistical significance. In addition, the 3-(4,5-Dimethylthiazol,2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to assay fibroblast cell growth.. mRNA transcripts were found in all three fibroblast cell populations with the cytokines having a stimulatory effect on its expression (P < 0.05). NPY mRNA was not detected in the cell strains. NPY-Y1 receptor protein expression was visualized by Western blotting, and there was no effect of IL-1β or TGF- β(1) on its expression. The mean concentration of NPY-Ir determined by radioimmunoassay in non-carious teeth was 19.40 ng x g(-1) (±17.03 SD) compared to 29.95 ng x g(-1) (±20.99 SD) in carious teeth (P < 0.05).. Human dental pulp fibroblasts express, but do not synthesize, NPY, demonstrating that the fibroblast is a target cell for NPY. The effect of proinflammatory cytokines suggests that fibroblasts play a neuroimmunomodulatory role in the pulpal response to dental caries and injury.

Topics: Blotting, Western; Cell Culture Techniques; Cell Proliferation; Cells, Cultured; Coloring Agents; Dental Caries; Dental Pulp; Fibroblasts; Humans; Interleukin-1beta; Membrane Proteins; Neuroimmunomodulation; Neuropeptide Y; Receptors, Neuropeptide Y; Reverse Transcriptase Polymerase Chain Reaction; Substance P; Tetrazolium Salts; Thiazoles; Transforming Growth Factor beta

Recent evidence suggests that the sympathetic nervous system may have a role in modulating neurogenic inflammation and bone remodelling. Neuropeptide Y (NPY) is a well-characterized neuropeptide transmitter in the peripheral sympathetic nervous system. NPY is known to be present in human dental pulp; however, quantitative data on NPY levels in pulpal health and disease in an adult population remain to be determined. The aims of the current study were to assess, quantitatively, NPY levels by radioimmunoassay and confirm the distribution of NPY fibres by immunocytochemistry in carious and non-carious adult human pulp tissue. Our results suggest changes in the levels and distribution of NPY in human dental pulp during the caries process, with significantly higher levels of NPY in carious compared with non-carious adult human teeth. Within the carious samples studied, our finding, that NPY levels were significantly elevated in mild/moderate caries, concurs with the hypothesis that NPY could have a modulatory role in pulpal inflammation and in reparative dentine formation.

Topics: Adult; Biomarkers; Dental Caries; Dental Pulp; Humans; Immunohistochemistry; Microscopy, Confocal; Nerve Fibers; Neuropeptide Y; Substance P; Sympathetic Nervous System; Tyrosine 3-Monooxygenase; Ubiquitin Thiolesterase

This immunohistochemical study sought to determine whether there are any differences in the peptidergic innervation of these pulps and whether dental caries is associated with changes in neuropeptide expression. Mandibular first permanent molars and second primary molars (n=120) were obtained from children requiring dental extractions under general anaesthesia. Extracted teeth were split longitudinally, placed in fixative, and categorized as intact, moderately carious or grossly carious. The coronal pulps were removed and 10-microm frozen sections were processed for indirect immunofluorescence. Double labelling employed combinations of the following antisera: (1) protein gene product 9.5, a general neuronal marker; (2) one of the neuropeptides calcitonin gene-related peptide (CGRP), substance P (SP), vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY), galanin (GAL), enkephalin (ENK) and somatostatin (SOM). Image analysis was then used to determine the percentage area of immunostaining for each label within different anatomical regions of the coronal pulp. Sparse or absent immunoreactivity for GAL, ENK and SOM made analysis impossible. Analysis of CGRP, SP and VIP revealed significant interdentition differences, with their expression being significantly greater in permanent teeth, but this was not the case for NPY, with primary and permanent teeth demonstrating a similar amount of label for this peptide. Both dentitions showed significant increases in CGRP, SP, VIP and NPY expression with caries progression. These findings could have biological and clinical importance in connection with nociception, inflammation and healing.

Topics: Analysis of Variance; Calcitonin Gene-Related Peptide; Child; Dental Caries; Dental Pulp; Dentition, Permanent; Disease Progression; Enkephalins; Fluorescent Antibody Technique, Indirect; Galanin; Humans; Molar; Neurogenic Inflammation; Neuropeptide Y; Neuropeptides; Somatostatin; Statistics, Nonparametric; Substance P; Tooth, Deciduous; Vasoactive Intestinal Peptide