Introduction: Biospecimens, such as urine, blood, saliva, tissue, cells, DNA, RNA, and protein, are biological material to be stored in a biorepository. They constitute critical resources of molecular data for basic and translational research integrated with diagnostic, therapeutics, and prevention of human diseases. The reliability of the molecular data is dependent on the quality and the consistency of the biospecimen being analyzed. The potential of human saliva as a valuable diagnostic fluid for oral and systemic conditions is being increasingly recognized. The aim of this study is to determine the molecular quality of unstimulated whole saliva (UWS) samples stored over a period of 1 to 5 years.
Materials and methods: UWS samples collected between 2006 and 2010 (20/year) and stored at -80°C were assessed for molecular integrity. The study was approved by the institutional review board of the Indiana University Purdue University at Indianapolis. Qualitative and quantitative measurements of salivary proteins were determined by gel electrophoresis and spectrophotometry. The salivary nucleic acid content was determined by the Nanodrop method and genetic analysis. The nature of the cellular sediment in the UWS was determined by amplification of specific gene.
Results: No significant differences were observed in the amount of proteins, nucleic acid, or in the number of viable cells in the UWS samples stored for 1 to 5 years.
Conclusion: Archived UWS samples could function as excellent biospecimen resources for measurement of protein, DNA, and RNA analytes, and act as an efficient source for human epithelial cells.