Comparative evaluation of saliva collection methods for proteome analysis

BackgroundSaliva collection devices are widely used for large-scale screening approaches. This study was designed to compare the suitability of three different whole-saliva collection approaches for subsequent proteome analyses.MethodsFrom 9 young healthy volunteers (4 women and 5 men) saliva samples were collected either unstimulated by passive drooling or stimulated using a paraffin gum or Salivette® (cotton swab). Saliva volume, protein concentration and salivary protein patterns were analyzed comparatively.ResultsSamples collected using paraffin gum showed the highest saliva volume (4.1 ± 1.5 ml) followed by Salivette® collection (1.8 ± 0.4 ml) and drooling (1.0 ± 0.4 ml). Saliva protein concentrations (average 1145 μg/ml) showed no significant differences between the three sampling schemes. Each collection approach facilitated the identification of about 160 proteins (≥ 2 distinct peptides) per subject, but collection-method dependent variations in protein composition were observed.ConclusionPassive drooling, paraffin gum and Salivette® each allows similar coverage of the whole saliva proteome, but the specific proteins observed depended on the collection approach. Thus, only one type of collection device should be used for quantitative proteome analysis in one experiment, especially when performing large-scale cross-sectional or multi-centric studies.