Immunohistochemical Analysis of Inducible and Endothelial Forms of Nitric Oxide Synthase in Cyclosporin A‐Induced Gingival Overgrowth

• Published in: Journal of periodontology (1970) Vol. 80; no. 10; pp. 1638 - 1647
• Main Authors: Gürkan, Ali, Emingil, Gülnur, Öktem, Gülperi, Selvi, Nur, Afacan, Beral, Tunç İlgenli, Töz, Hüseyin, Atilla, Gül
• Format: Journal Article
• Language: English
• Published: Chicago, IL American Academy of Periodontology 01-10-2009
• Subjects: Adolescent; Adult; Biological and medical sciences; Connective Tissue - drug effects; Connective Tissue - enzymology; Connective Tissue - pathology; CsA; Cyclosporine - adverse effects; Dental Plaque Index; eNOS; Epithelial Cells - drug effects; Epithelial Cells - enzymology; Epithelial Cells - pathology; Epithelium - drug effects; Epithelium - enzymology; Epithelium - pathology; Facial bones, jaws, teeth, parodontium: diseases, semeiology; Female; Gingiva - drug effects; Gingiva - enzymology; Gingiva - pathology; Gingival Crevicular Fluid - chemistry; Gingival Crevicular Fluid - enzymology; gingival overgrowth; Gingival Overgrowth - chemically induced; Gingival Overgrowth - enzymology; Gingival Overgrowth - pathology; gingivitis; Gingivitis - enzymology; Humans; Image Processing, Computer-Assisted - methods; Immunohistochemistry; Immunosuppressive Agents - adverse effects; inducible NOS; Keratinocytes - drug effects; Keratinocytes - enzymology; Keratinocytes - pathology; Kidney Transplantation; Male; Medical sciences; Middle Aged; Nitrates - analysis; nitric oxide; Nitric Oxide Synthase Type II - analysis; Nitric Oxide Synthase Type III - analysis; Nitrites - analysis; Non tumoral diseases; Otorhinolaryngology. Stomatology; Periodontal Index; Young Adult; Immunohistochemistry; eNOS; gingivitis; Enzyme; Stomatology; inducible NOS; Dentistry; Nitric-oxide synthase; Gingivitis hyperplasia; CsA; Anatomic pathology; Periodontal disease; Nitric oxide; Ciclosporin; Oxidoreductases; Immunosuppressive agent; gingival overgrowth
• ISSN: 0022-3492; 1943-3670
• DOI: 10.1902/jop.2009.090138

Background: The contribution of nitric oxide (NO) to immune response and matrix degradation in the periodontal environment suggests a role for NO and NO‐synthase (NOS) activity in the pathogenesis of cyclosporin A (CsA)‐induced gingival overgrowth (GO). However, current knowledge on this topic is limited to experimental animal studies. The present study was undertaken on the basis of a hypothesis whether altered nitrite/nitrate levels in gingival crevicular fluid (GCF) and endothelial NOS (eNOS) and inducible NOS (iNOS) immunoreactivity in gingiva of CsA‐treated patients contribute to the pathogenesis of CsA‐induced GO.
Methods: Twenty‐four CsA‐medicated renal transplant patients with GO (GO+; n = 12) or without GO (GO−; n = 12), 10 gingivitis, and 10 healthy subjects were included in the study. GCF samples from two proximal sites facing interdental papilla were collected, and papilla was excised. iNOS and eNOS were determined by immunohistochemistry. GCF nitrite/nitrate levels were analyzed based on the Griess reaction.
Results: Weak iNOS immunostaining was observed in the healthy and GO− groups. In the gingivitis and GO+ groups, iNOS immunostaining significantly increased in connective tissue. Epithelial immunostaining of iNOS was localized to basal keratinocytes and the lower layer of stratum (str.) spinosum in the gingivitis group. In the GO+ group, iNOS immunostaining was differentially localized to keratinocytes of str. superficiale but considerably decreased in the str. basale. Weak eNOS immunostaining was found in the healthy and GO− groups, whereas higher immunostaining was observed in the gingivitis and GO+ groups. No intergroup differences were observed regarding nitrite/nitrate levels in GCF.
Conclusion: CsA differentially upregulated iNOS, but not eNOS, in overgrown gingiva, which may play a pivotal role in the pathogenesis of CsA‐induced GO.