Original Article Serum sTWEAK levels in chronic periodontitis and type 2 diabetes mellitus Anirudh B. Acharya a, * , Apoorva Chandrashekar b , Swetha Acharya c , Leena Shettar a , Srinath Thakur a a Department of Periodontics, S.D.M. College of Dental Sciences & Hospital, Dharwad, 580009, Karnataka, India b Department of Periodontics, A.J. Shetty Institute of Dental Sciences, Mangalore, 575004, Karnataka, India c Department of Oral Pathology & Microbiology, S.D.M. College of Dental Sciences & Hospital, Dharwad, 580009, Karnataka, India article info Article history: Received 16 February 2019 Accepted 14 March 2019 Keywords: Chronic periodontitis Diabetes mellitus Type 2 Cytokine TWEAK Serum Biomarkers abstract Aim: The two-way relationship between diabetes mellitus and periodontitis has been extensively studied with various interconnected biomarkers sharing a link. Soluble Tumour Necrosis Factor-like Weak inducer of apoptosis (sTWEAK) is gaining attention as an important mediator in chronic inflam- matory diseases. Thus, the aim of this study was to detect, estimate and compare the levels of sTWEAK in the serum of health, chronic periodontitis (CP), and CP with type 2 diabetes mellitus (T2DM). Materials and methods: Forty-five participants between 18 and 65 years were divided into groups of 15 each as Group 1: healthy, Group 2: CP, and Group 3: CP þ T2DM. Clinical periodontal parameters and glycemic status were assessed. sTWEAK in serum was estimated using a commercially available ELISA kit. The data was statistically analyzed. Results: sTWEAK was detected in all participants. Significant differences were observed between the groups for sTWEAK; highest in health, lower in CP and lowest in CP þ T2DM. In the diseased groups, the clinical and glycemic parameters correlated positively with each other, whereas sTWEAK correlated negatively with each of the parameters. Conclusion: The literature reports lower concentrations of systemic sTWEAK in T2DM which may be comparable to our observations in CP þ T2DM when compared to health and its negative correlation with all the parameters suggesting an association with both clinical periodontal parameters and glycemic levels. However, serum sTWEAK levels may not be necessarily elevated in periodontitis as previously reported, and hence has the potential to be studied extensively for clarification with its association with T2DM. © 2019 Diabetes India. Published by Elsevier Ltd. All rights reserved. 1. Introduction Chronic periodontitis (CP) is a complex inflammatory disease represented primarily by a poly-microbial oral infection [predom- inantly Gram negative anaerobic bacteria] that leads to gingival inflammation and destruction of periodontal tissues [1]. Although CP is initiated by bacteria, the host response plays an important role in the inflammatory/immunological responses in CP [2]. A mech- anism exists between bacterial stimulation and tissue damage i.e., production of pro-inflammatory mediators which collectively contribute to periodontal tissue destruction [3]. Type 2 diabetes mellitus (T2DM) is a metabolic disorder of multiple etiology characterized by chronic hyperglycemia as well as carbohydrate, fat and protein metabolism derangement because of defects in insulin secretion, action, or both. A bidirectional rela- tionship in the pathogenesis of CP and T2DM with inflammation and the action of various molecular mediators including cytokines common to both has been reported [4,5]. Tumour necrosis factor-like weak inducer of apoptosis (TWEAK) is described as a member of the tumour necrosis factor TNF super family [6], which plays a significant role in inflammation. It is expressed by most of the cells involved in inflammation such as macrophages/monocytes, T-cells, plasma cells and also fibroblasts. It can exist in two forms, i.e., a full-length membrane-associated (mTWEAK) and a soluble (sTWEAK) type. TWEAK ligates with its receptor fibroblast growth factor-inducible protein (Fn14), bringing * Corresponding author. E-mail address: abacharya@gmail.com (A.B. Acharya). Contents lists available at ScienceDirect Diabetes & Metabolic Syndrome: Clinical Research & Reviews journal homepage: www.elsevier.com/locate/dsx https://doi.org/10.1016/j.dsx.2019.03.027 1871-4021/© 2019 Diabetes India. Published by Elsevier Ltd. All rights reserved. Diabetes & Metabolic Syndrome: Clinical Research & Reviews 13 (2019) 1609e1613