Salivary proteomics in bisphosphonate-related osteonecrosis of the jaw
V Thumbigere-Math, B S Michalowicz, E P de Jong, T J Griffin, D L Basi, P J Hughes, M L Tsai, K K Swenson, L Rockwell, R Gopalakrishnan, V Thumbigere-Math, B S Michalowicz, E P de Jong, T J Griffin, D L Basi, P J Hughes, M L Tsai, K K Swenson, L Rockwell, R Gopalakrishnan
Abstract
Objective: The objective of this study was to identify differentially expressed salivary proteins in bisphosphonate-related osteonecrosis of the jaw (BRONJ) patients that could serve as biomarkers for BRONJ diagnosis.
Subjects and methods: Whole saliva obtained from 20 BRONJ patients and 20 controls were pooled within groups. The samples were analyzed using iTRAQ-labeled two-dimensional liquid chromatography-tandem mass spectrometry.
Results: Overall, 1340 proteins were identified. Of these, biomarker candidates were selected based on P-value (<0.001), changes in protein expression (≥1.5-fold increase or decrease), and unique peptides identified (≥2). Three comparisons made between BRONJ and control patients identified 200 proteins to be differentially expressed in BRONJ patients. A majority of these proteins were predicted to have a role in drug metabolism and immunological and dermatological diseases. Of all the differentially expressed proteins, we selected metalloproteinase-9 and desmoplakin for further validation. Immunoassays confirmed increased expression of metalloproteinase-9 in individual saliva (P = 0.048) and serum samples (P = 0.05) of BRONJ patients. Desmoplakin was undetectable in saliva. However, desmoplakin levels tended to be lower in BRONJ serum than controls (P = 0.157).
Conclusions: Multiple pathological reactions are involved in BRONJ development. One or more proteins identified by this study may prove to be useful biomarkers for BRONJ diagnosis. The role of metalloproteinase-9 and desmoplakin in BRONJ requires further investigation.
Keywords: biological markers; biomarkers; bisphosphonate; bisphosphonate-related osteonecrosis of the jaw; osteonecrosis of the jaw; proteomics; saliva.
© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
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Source: PubMed