Keynote Address: Physiological and Pathological Features of Human Saliva Carried out by Top-down Proteomic Approaches

Top-down proteomics is based on liquid chromatographic fractionation (HPLC) of the naturally occurring proteins in body fluids coupled with their precise mass measurement (MS) carried out by electrospray ionization (ESI). The structure of the proteins and their derivatives is established by different chemical and biochemical (i.e. enzymatic) reactions followed by different low and high resolution MS experiments. The intact protein mass measurement discloses information to discriminate among different isoforms and post-translational modifications. This HPLC-ESI-MS based proteomic platform allowed evidencing the modification of the composition of human saliva as a function of age, with particular concern to pediatric age. Knowledge of physiological variation is mandatory for a proper comparison of “normal” salivary proteome to that detectable in some pathological conditions. This comparison offered clues for the molecular basis of the disease and its sequelae in a subgroup of autism spectrum disorder patients as well as in patients with insulin-dependent diabetes mellitus.