Expression of transient receptor potential vanilloid receptor 1 and toll-like receptor 4 in aggressive periodontitis and in chronic periodontitis

Abstract

BACKGROUND AND OBJECTIVE: The objective of the present study was to evaluate the expression and the distribution of the transient receptor potential vanilloid receptor 1 (TRPV1) and of toll-like receptor 4 (TLR4) in tissue samples from patients with periodontal disease (aggressive periodontitis and chronic periodontitis) and from healthy controls. MATERIAL AND METHODS: Ten tissue samples from each disease group (aggressive periodontitis and chronic periodontitis) and from healthy subjects were obtained during routine oral surgical procedures. Subgingival specimens were collected from sites with advanced loss of support (probing depth>5mm) and specimens from the corresponding healthy controls were obtained during tooth extraction for orthodontic reasons or following surgical extraction of an impacted third molar. The distribution of TRPV1 and TLR4 receptors in human gingival tissue was studied by immunohistochemistry. RESULTS: Both TLR4 and TRPV1 were detected in gingival tissues from healthy subjects, and from patients with chronic periodontitis and aggressive periodontitis, particularly in gingival keratinocytes, fibroblasts, inflammatory cells and the endothelial lining of capillaries in connective tissues. Histologic examination of the samples from healthy controls disclosed that clinically healthy gingiva does not correspond to histologically healthy gingiva. Subsequently, these samples were redesignated as gingivitis samples. TRPV1 was down-regulated in all cell types in samples obtained from patients with chronic periodontitis compared to samples obtained from patients with gingivitis, whereas TLR4 was down-regulated only in the epithelium and in gingival fibroblasts. In contrast, the levels of these markers in patients with aggressive periodontitis were similar to those in healthy patients. CONCLUSION: Local expression of TRPV1 and TLR4 in gingival tissues may contribute to both physiological and pathological processes in the periodontium. Our data suggest that TRPV1 and TLR4 may play a role specifically in the pathophysiology of chronic periodontitis.