neuropeptide-y and Periodontitis

This review provides an update on genome-wide association studies in periodontitis. Studies in populations with European ancestry have dominated the landscape of periodontitis genetics studies but, increasingly, studies in Asian populations are being reported. The review also summarizes evidence for suggested associated genetic variations. The loci associated with genome-wide association studies consist of noncoding variations, many of which are predicted to modulate levels of gene expression. In this article, the biological functions of the genes that are nearest to the associations and their implications for disease etiology are also examined. A major challenge in the genetics of periodontitis is identification of the causal variant(s) underlying associations with periodontitis, elucidation of the molecular mechanisms that are potentially affected by the associated variants, and understanding how they contribute to disease phenotypes and traits. This will allow emerging medical initiatives to make clinical use of genetic discoveries. Large collaborative studies, across research centers and across subspecialties and disciplines, will be required to realize the promise of genetic discovery in periodontitis.

Topics: Alleles; alpha-Defensins; Asian People; beta-Thromboglobulin; Chemokines, CXC; Chronic Periodontitis; Gene Expression; Genetic Predisposition to Disease; Genetic Variation; Genome-Wide Association Study; Genotype; Glycosyltransferases; Humans; Neuropeptide Y; Peptides, Cyclic; Periodontitis; Phenotype; Plasminogen; Platelet Factor 4; RNA, Long Noncoding; Sialic Acid Binding Immunoglobulin-like Lectins

Neuropeptide Y (NPY) coordinates inflammation and bone metabolism which are central to the pathogenesis of periodontitis. The present study was designed to determine whether NPY was quantifiable in human gingival crevicular fluid (GCF) and to test the null hypothesis that GCF levels of NPY were the same in periodontal health and disease. A subsidiary aim was to determine the potential functionality of released NPY by detecting the presence of NPY Y1 receptors in gingival tissue.. The periodontitis group consisted of 20 subjects (10 females and 10 males) mean age 41.4 (S.D. 9.6 years). The control group comprised 20 subjects (10 females and 10 males) mean age 37.4 (S.D. 11.7 years). NPY levels in GCF were measured in periodontal health and disease by radioimmunoassay. NPY Y1 receptor expression in gingival tissue was determined by Western blotting of membrane protein extracts from healthy and inflamed gum.. Healthy sites from control subjects had significantly higher levels of NPY than diseased sites from periodontitis subjects. NPY Y1 receptor protein was detected in both healthy and inflamed gingival tissue by Western blotting.. The significantly elevated levels of NPY in GCF from healthy compared with periodontitis sites suggests a tonic role for NPY, the functionality of which is indicated by the presence of NPY Y1 receptors in local gingival tissue.

Topics: Adult; Blotting, Western; Female; Gingiva; Gingival Crevicular Fluid; Humans; Male; Middle Aged; Neuropeptide Y; Periodontal Pocket; Periodontitis; Radioimmunoassay; Receptors, Neuropeptide Y

The aims of this study were to evaluate the effect of inferior alveolar nerve (IAN) axotomy on periodontal (PDL) and pulpal blood flow incident to experimental tooth movement and to investigate whether nerve fiber regeneration coincides with blood flow changes. The first right mandibular molar was moved mesially for 3, 7, and 14 days after ipsilateral IAN axotomy in 29 rats. Four rats served as unoperated controls. At the end of each experimental period fluorescent microspheres (FM) were injected into the left ventricle and thereafter counted in serial sections in the PDL and pulp of the right and left first mandibular molars. The number of FM per tissue volume was taken as a measure of blood flow. Re-innervation of nerve fibers was mapped immunohistochemically 7, 14, and 21 days after IAN axotomy in 9 rats that had no orthodontic appliance. The statistical analysis showed no significant differences in the number of FM/mm3 PDL between the denervated and the contralateral side at 3 and 7 days. At 14 days the PDL on the denervated side showed a significant increase in the number of FM/mm3, coinciding with the initial periodontal nerve fiber re-innervation. In the pulp no significant differences were found between the denervated and the contralateral, innervated side in any experimental period. It can be concluded that IAN axotomy postpones an increase in periodontal blood flow until a sensory tissue re-innervation is established, thus indicating that neurogenic mechanisms play an important role in the development of the inflammatory reaction induced by experimental tooth movement.

Topics: Animals; Axotomy; Calcitonin Gene-Related Peptide; Dental Pulp; Fluorescent Dyes; Follow-Up Studies; Immunohistochemistry; Male; Mandibular Nerve; Microspheres; Molar; Nerve Fibers; Nerve Regeneration; Neuropeptide Y; Odontoblasts; Periodontal Ligament; Periodontitis; Pulpitis; Rats; Rats, Inbred Strains; Rats, Wistar; Regional Blood Flow; Tooth Movement Techniques; Tooth Root

Immunohistochemical methods have been used to study the occurrence of neuronal markers in human gingiva from periodontitis-affected sites. In periodontitis-affected buccal gingiva densely distributed neurofilament (NF)-immunoreactive (IR) fiber bundles were observed in the deeper parts of the propria, while NF-IR single fibers occurred in the superficial propria and occasionally in the buccal epithelium. Periodontitis-affected gingiva obtained from interproximal sites showed only sparsely distributed NF-IR fibers. Single nerve fibers immuno-reactive to the peptides substance P and calcitonin gene-related peptide occurred close to or within the epithelium in both buccal and interproximal gingiva. Around blood vessels neuropeptide Y-, peptide histidine-isoleucine amide- and vasoactive intestinal polypeptide-IR fibers were occasionally observed, while clusters of gamma-melanocyte-stimulating hormone-IR cells were found in the propria, in addition to gamma-melanocyte-stimulating hormone IR nerve fibers. Somatostatin-IR dendritic cells were seen in epithelium and propria of buccal and interproximal gingiva, although a high variability in the number of SOM-IR cells was observed. All neuronal markers studied showed a similar distribution in material obtained from young patients with clinically healthy gingivae, although the number of NF-IR fibers in the propria in these subjects was lower. The results demonstrate that in gingiva obtained from periodontitis-affected sites several different biologically active peptides occur in both nerve fibers and cells. At least some of these substances could possible play a role in the inflammatory process. However, since clinically normal gingiva was shown to contain nerve fibers and cells expressing immunoreactivity to the substances studied, no unique periodontitis-induced expression of the neuronal markers studied was found. Thus, any alteration of these substances during the periodontitis process remains to be elucidated.

Topics: Adolescent; Adult; Calcitonin; Calcitonin Gene-Related Peptide; Child; Cytoskeleton; Gingiva; Humans; Immunohistochemistry; Intermediate Filaments; Melanocyte-Stimulating Hormones; Middle Aged; Neuropeptide Y; Neuropeptides; Peptide PHI; Periodontitis; Somatostatin