Salivary Proteomic Profile of Cystic Fibrosis in Children With Gingivitis

Objectives: Cystic fibrosis (CF) is a chronic inflammatory disease in children with saliva being a potential reservoir of bacterial colonization. This study investigated the salivary proteome in CF and systemically healthy (SH) children, with gingivitis (G) or periodontal health (PH).
Methods: CF (n=10) and age- and gender-matched SH children (n=10) were enrolled, unstimulated saliva was collected, full-mouth periodontal parameters were recorded. Label-free quantitative proteomics using liquid chromatography-tandem mass spectrometry investigated the saliva proteome. Protein abundances were calculated using Progenesis QI based on the UniProt human database and HOMD. Regulated proteins were classified as p<0.05 and human proteins further characterized by MetaCore for ontology enrichment analysis.
Results: CF compared to SH had significantly higher bleeding on probing (BOP) scores (28.98±25.06 Vs 20.32±18.81, p=0.001), but plaque index (PI) showed no differences (p>0.05). The children were stratified based on periodontal diagnosis as SH-PH (5.6yrs±1.5, F:M:3:2), SH-G (8.6yrs±2.5, F:M:2:3), CF-PH (6.0yrs±3.2, F:M:3:3), CF-G (8.5yrs±2.9, F:M:3:1). 855 proteins (≥2 peptides, FDR=0.35%) were quantified excluding reverse sequences and contaminants. 629 proteins were of human, 226 of bacterial origin. Comparative analysis on the former revealed 86 (54↑:32↓) regulated proteins between SH-PH and SH-G, 73 (0↑:73↓) between CF-PH and CF-G, 64 (19↑:45↓) between SH-PH and CF-PH and 46 (34↑:12↓) between SH-G and CF-G. SH-G compared to SH-PH showed enrichment in processes such as ‘apoptosis’ and ‘signal transduction’ while CF-G compared to CF-PH was enriched in ‘Th17 immune response’, ‘ossification and bone remodeling’ and ‘IFN-γ signaling’.
Conclusions: CF compared to SH children presented with higher BOP independently of their plaque scores. The salivary proteome of CF children reflected a regulation pattern towards bone resorption and potentially periodontal disease progression. These findings enhance the understanding of the mechanisms driving exacerbated gingival inflammation in children with CF and identify salivary proteins with potential for use as indicators of disease.