Anti‐Apoptotic and Pro‐Apoptotic Bcl‐2 Family Proteins in Peri‐Implant Diseases

Abstract Objectives Intrinsic apoptosis, which is regulated by Bcl‐2 family proteins, has an important role in chronic inflammatory diseases. The aim of the study was to identify the tissue levels and ratios of anti‐ and pro‐apoptotic Bcl‐2 family proteins in peri‐implant diseases. Materials and Methods Twenty‐three individuals with peri‐implant mucositis, 25 individuals with peri‐implantitis, and 24 controls were included. The following clinical parameters were recorded: keratinized mucosa width, modified bleeding index, probing depth, modified plaque index, modified gingival index, and keratinized tissue thickness. Marginal alveolar bone assessments were performed by a software program. Granulation tissues were collected during treatments of peri‐implant diseases. The control tissue samples were collected during the second stage of implant surgery. The tissue levels of Bcl‐2 family pro‐apoptotic (Bak, Bax, active caspase‐3) and anti‐apoptotic (Bcl‐2, Bcl‐xL, Mcl‐1) proteins were determined by multiplex immunoassay method. Results The pro‐apoptotic proteins; Bak, Bax and anti‐apoptotic proteins Bcl‐2, Bcl‐xL, Mcl‐1 were detected significantly higher in controls compared with patients with peri‐implant mucositis and peri‐implantitis ( p < .001), respectively. The higher active caspase‐3 levels were also detected in controls in comparison with peri‐implant mucositis ( p = .018) and peri‐implantitis ( p = .005). Anti‐apoptotic: pro‐apoptotic protein ratios (Bcl‐2:Bax, p < .001; Bcl‐2:Bak, p = .01; Bcl‐xL: Bax, p = .006, Bcl‐xL:Bak, p = .011; Mcl‐1:Bak, p < .001) were significantly increased in diseased groups. A positive correlation was demonstrated between clinical variables and anti‐apoptotic: pro‐apoptotic ratios. Conclusion Our findings indicate dysregulation of the Bcl‐2 family proteins in peri‐implant diseases. This unregulated response may disturb the homeostasis of peri‐implant tissue.