Label-free quantitative proteomic analysis of gingival crevicular fluid to identify potential early markers for root resorption

Abstract

Background Orthodontically-induced root resorption is an iatrogenic effect and it cannot be examined regularly due to the harmful effects of sequential doses of radiation with more frequent radiography. This study aims to compare protein abundance (PA) of pre-treatment and during orthodontic treatment for root resorption and to determine potential early markers for root resorption. Methods Ten subjects (n = 10) who had upper and lower fixed appliances (MBT, 3 M Unitek, 0.022″ × 0.028″) were recruited for this study. Human gingival crevicular fluid (GCF) was obtained using periopaper strips at pre-treatment (T0), 1 month (T1), 3 months (T3), and 6 months (T6) of orthodontic treatment. Periapical radiographs of the upper permanent central incisors were taken at T0 and T6 to measure the amount of root resorption. Identification of changes in PA was performed using liquid chromatography-tandem mass spectrometry. Student’s t-test was then performed to determine the significance of the differences in protein abundance before and after orthodontic treatment. Results Our findings showed that all ten subjects had mild root resorption, with an average resorption length of 0.56 ± 0.30 mm. A total of 186 proteins were found to be commonly present at T0, T1, T3, and T6. There were significant changes in the abundance of 16 proteins (student’s t-test, p ≤ 0.05). The increased PA of S100A9, immunoglobulin J chain, heat shock protein 1A, immunoglobulin heavy variable 4–34 and vitronectin at T1 suggested a response to stress that involved inflammation during the early phase of orthodontic treatment. On the other hand, the increased PA of thymidine phosphorylase at T3 suggested growth promotion and, angiogenic and chemotactic activities. Conclusions The identified proteins can be potential early markers for root resorption based on the increase in their respective PA and predicted roles during the early phase of orthodontic treatment. Non-invasive detection of root resorption using protein markers as early as possible is extremely important as it can aid orthodontists in successful orthodontic treatment.

Clinical and radiographic characterization of external root resorption

“…Huang [11] detectó alteraciones en los niveles de proteínas de dentina en el líquido crevicular humano. Mohd [36] detectó seis proteínas (S100A9, IGJ, HSPA1A, IGHV4-34, TYMP y VTN) que mostraron aumentos significativos durante la fase temprana de los tratamientos de ortodoncia, lo que los convierte en candidatos como biomarcadores potenciales que pueden explotarse para la detección de la reabsorción radicular. Estudios recientes indican qué biomarcadores encontrados en la saliva muestran un aumento significativo de interleucina-7, interleucina-10, interleucina-12p70, interferón γ, proteínas y metabolitos, y un descenso significativo de interleucina-4 cuando existe una reabsorción radicular externa inflamatoria [18,36].…”

“…Mohd [36] detectó seis proteínas (S100A9, IGJ, HSPA1A, IGHV4-34, TYMP y VTN) que mostraron aumentos significativos durante la fase temprana de los tratamientos de ortodoncia, lo que los convierte en candidatos como biomarcadores potenciales que pueden explotarse para la detección de la reabsorción radicular. Estudios recientes indican qué biomarcadores encontrados en la saliva muestran un aumento significativo de interleucina-7, interleucina-10, interleucina-12p70, interferón γ, proteínas y metabolitos, y un descenso significativo de interleucina-4 cuando existe una reabsorción radicular externa inflamatoria [18,36]. A pesar de encontrar una relación entre los biomarcadores en el fluido crevicular gingival y el desarrollo de reabsorción radicular, es necesaria más evidencia acerca del uso clínico de estos biomarcadores [18].…”