Impact of peri‐implantitis on the proteome biology of crevicular fluid: A pilot study.

Background: The proteome of the peri‐implant crevicular fluid (PICF) has not been systematically investigated. The aim of the present study was to reveal the proteome biology of dental implants affected with peri‐implantitis. Methods: Patients with at least one diseased implant were included (probing depth ≥6 mm, ≥3 mm peri‐implant radiological bone loss). Using sterile paper strips, samples were collected from healthy implants (I), healthy teeth (T) and peri‐implantitis affected implants (P). Proteome analysis was performed using liquid chromatography — tandem mass spectrometry (LC‐MS/MS) and data independent acquisition, allowing the identification and quantification of human and bacterial proteins as well as semi‐specific peptides. Results: A total of 38 samples from 14 patients were included in the study; 2332 different human proteins were identified across all samples. No differentially expressed proteins between T and I were found. Comparing P to I, 59 proteins were found upregulated and 31 downregulated in P with significance. Upregulated proteins included proinflammatory proteins such as immunoglobulins, dysferlin, and S100P, as well as antimicrobial proteins, for example, myeloperoxidase or azurocidin. Gene ontology analysis further revealed higher activity of immunological pathways. Proteolytic patterns indicated the activity of inflammatory proteins such as cathepsin G. A total of 334 bacterial proteins were identified and quantified. Peri‐implantitis showed elevated proteolytic activity. Conclusion: I and T share similarities in their proteome, while diseased implants deviate strongly from healthy conditions. The PICF proteome of peri‐implantitis affected sites exhibits an inflammatory fingerprint, dominated by neutrophil activity when compared with healthy implants. [ABSTRACT FROM AUTHOR]