Inducible nitric oxide synthase expression in periodontitis

Abstract

Recently, nitric oxide (NO) has been shown to be vital in inflammatory processes. Nitric oxide synthase (NOS) exists in three different isoforms, two constitutively produced with physiological roles, and an inducible form, iNOS, which is involved in inflammation. This study examined the localisation of iNOS in biopsies from patients with periodontitis using immunohistochemistry, and compared these with healthy tissue biopsies. Biopsies were obtained from 16 periodontitis patients undergoing periodontal surgery and from clinically healthy tissues of 5 patients having crown lengthening procedures. The periodontitis diseased tissue demonstrated a greater level of iNOS expression than the healthy tissue. The source of iNOS in the periodontal tissues was determined by our monoclonal antibody to be the macrophage, with the endothelial cells also contributing. A role for NO in the inflammatory response of periodontal tissues is suggested, but the precise role requires further elucidation.

Nitric oxide in gingival crevicular fluid and nitric oxide synthase expression in the gingiva of patients with sickle cell disease

“…iNOS activity was reported to increase in ligatureinduced periodontitis [27], experimental periodontitis [30], and chronic periodontitis [20,26,31]. Higher levels of iNOS expression were observed in chronic periodontitis tissues than in clinically healthy gingival tissues [20,23,26,27,31] and a previous study of ours showed that iNOS increased in the gingival tissue of aggressive periodontitis patients (unpublished data). In various animal models iNOS was susceptible to infections by a variety of pathogens [32][33][34][35].…”

“…NO has been implicated in the pathogenesis of apical infection [45], periapical granulomas [46], and inflamed human dental pulp [47]. Increased iNOS expression in gingiva was shown in periodontitis [20,22,26,28,31], ligature-induced periodontitis [27], experimental periodontitis [30,46], inflamed gingiva [23], localized aggressive periodontitis [21], and recently by our group in aggressive periodontitis (unpublished data).…”

“…It was reported that NOS activity plays a role in stimulating production of NO x . iNOS was observed in dental tissues, and increased iNOS production was reported in gingival crevicular fluid (GCF) [19] and gingival tissues [20][21][22][23] in different periodontal diseases, but iNOS activity was not observed in the gingival tissues in sterile animals [24]. Periodontal diseases are inflammatory disorders that cause tissue damage and loss via the complex interactions between pathogenic bacteria and host immune response.…”

“…NO synthesis and iNOS activity increase in inflamed periodontal tissues [20,[25][26][27][28] as a result of macrophage infiltration in periodontal tissues [29]. The literature includes only a few studies that evaluated iNOS activity in inflamed periodontal tissues.…”

The Expression of Nitric Oxide in the Gingival Tissue in Subjects with Periodontitis and Chronic Pain

“…Although both NO and substance P, classical NANC neurotransmitters, are implied in both pathophysiology of chronic pain (Anbar & Gratt) and PD (Lappin et al, 2000) as well, including primary headache conditions (Anbar & Gratt), there are no studies acknowledged so far which investigate its behavior in patients the gingival expression of sP and NO since both are related to the mechanisms of persistent pain (Anbar & Gratt) and both are also related to the pathophysiology of PD (Lappin et al, 2000) and some primary headaches as well (Goodale, 1981). These analyses were made in the total sample and epithelial or connective tissues.…”