Salivary proteome patterns of individuals exposed to High Altitude

Identification of molecular signatures having key roles in hypobaric hypoxia by analysing the salivary proteome. Saliva holds a promising future in the search for new clinical biomarkers that are easily accessible, less complex, accurate, and cost effective as well as being non-invasive.

We employed qualitative proteomics approach to develop discriminatory biomarker signatures from human saliva exposed to hypobaric hypoxia. Salivary proteins were analyzed and compared between age-matched healthy subjects exposed to high altitude (∼13700 ft) for seven days (HAD7) with control subjects at sea level (Normoxia) by using 2-Dimensional gel electrophoresis/Mass Spectrometry approach.

Several proteins with significant differential expression were found. The up-regulated proteins were apoptosis inducing factor-2, cystatin S, cystatin SN and carbonic anhydrase 6. The down regulated proteins were polymeric immunoglobulin receptor, alpha-enolase and prolactin-inducible protein. Further confirmation of the altered proteins such as alpha enolase, carbonic anhydrase 6, prolactin-inducible protein, apoptosis inducing factor 2, cystatin S and cystatin SN were performed using immunoblotting. The expression patterns of the selected proteins observed by immunoblot were in concurrence with 2-Dimesional gel electrophoresis results, therefore affirming the authenticity of the proteomic investigation.

This study provides the proof of concept of salivary biomarkers for the non-invasive detection of hypobaric hypoxia induced effects. It is highly feasible to turn these biomarkers into an applicable clinical test after large scale validation.