{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,29]],"date-time":"2026-09-29T20:23:16Z","timestamp":1790713396902,"version":"4.1.0"},"reference-count":45,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2026,4,13]],"date-time":"2026-04-13T00:00:00Z","timestamp":1776038400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Background\/Objectives: Periodontitis grade reflects differences in disease progression and risk, yet the underlying host-response signatures that distinguish grade B from grade C are not fully elucidated. Nuclear receptors involved in inflammation and tissue homeostasis may contribute to these biological differences. The present study aimed to evaluate the expression of peroxisome proliferator-activated receptor-\u03b3 (PPAR-\u03b3), retinoid X receptor-\u03b1 (RXR-\u03b1), and vitamin D receptor (VDR) in gingival tissues from periodontally healthy individuals and from patients with grade B and grade C periodontitis, with the primary comparison focusing on grade-related differences within the same disease stage (stage 3). Methods: Forty-five participants were allocated to three groups: Group 1, healthy controls; Group 2, stage 3 grade B periodontitis; and Group 3, stage 3 grade C periodontitis. Clinical parameters, including plaque index (PI), gingival index (GI), and clinical attachment loss (CAL), were recorded. Fibroblast and inflammatory cell density, and immunohistochemical expression levels of PPAR-\u03b3, RXR-\u03b1, and VDR were assessed on histological sections. Results: Compared with healthy controls, both periodontitis groups showed lower fibroblast cell counts and higher inflammatory cell counts. PPAR-\u03b3 expression was significantly higher in Group 3 than in the other groups, whereas RXR-\u03b1 and VDR expression were higher in Group 1 than in Groups 2 and 3. Conclusions: These findings suggest that increasing disease grade within stage 3 periodontitis is associated with increased PPAR-\u03b3 expression, whereas RXR-\u03b1 and VDR expression primarily distinguish healthy from diseased gingival tissues. This nuclear receptor profile may help explain biological differences between healthy, grade B and grade C periodontitis and support future risk-stratified host-modulatory approaches.<\/jats:p>","DOI":"10.3390\/jcm15082957","type":"journal-article","created":{"date-parts":[[2026,4,14]],"date-time":"2026-04-14T08:14:17Z","timestamp":1776154457000},"page":"2957","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["PPAR-\u03b3, RXR-\u03b1, and VDR Expression in Gingival Tissues of Patients with Grade B and Grade C Periodontitis: A Cross-Sectional Clinical Immunohistochemistry Study"],"prefix":"10.3390","volume":"15","author":[{"given":"Ozkan","family":"Karatas","sequence":"first","affiliation":[{"name":"Department of Periodontology, Faculty of Dentistry, Tokat Gaziosmanpasa University, 60250 Tokat, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fikret","family":"Gevrek","sequence":"additional","affiliation":[{"name":"Department of Histology and Embryology, Faculty of Medicine, Tokat Gaziosmanpasa University, 60250 Tokat, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,4,13]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"S1","DOI":"10.1002\/JPER.18-0157","article-title":"A new classification scheme for periodontal and peri-implant diseases and conditions\u2014Introduction and key changes from the 1999 classification","volume":"89","author":"Caton","year":"2018","journal-title":"J. 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