Usefulness of Saliva Samples for Biomarker Studies in Radiation Research

Abstract

Salivary biomarkers have important potential to facilitate breakthroughs in epidemiologic studies, management of emergency situations, and detection and surveillance of diseases by medical staff. During the last decade, an increasing number of studies on salivary biomarkers have been published as a consequence of the impressive development of new high-throughput technologies. Here, we present a review of salivary biomarkers potentially useful in ionizing radiation (IR) research, particularly in molecular epidemiologic studies. Although several salivary biomarkers of cancer and other IR-associated diseases have been identified, few salivary biomarkers of exposure and no biomarker of susceptibility or effects specific to IR have been reported so far. Further studies are therefore needed to fully assess the potential of saliva as a source of biomarkers in the radiation research field. Although the use of saliva samples is not without drawbacks, it could represent an ideal noninvasive alternative to blood, particularly in children and in the context of large molecular epidemiology studies on the effects of low doses of IR, where, given the expected limited magnitude of effects, an extensive number of samples is required to reach statistical significance.

Assessment of Saliva as a Potential Biofluid for Biodosimetry: A Pilot Metabolomics Study in Mice

“…To date, urinary and blood metabolomic studies have been limited in their ability to discern tissue-specific biomarkers. On the other hand, saliva metabolomics may be a better representative due to locally affected tissues (12, 13). To the best of our knowledge, this is the first study to investigate salivary radiation metabolomics, although different salivary parameters, such as electrolytes and amylase, have been investigated by others (13, 19).…”

“…On the other hand, saliva metabolomics may be a better representative due to locally affected tissues (12, 13). To the best of our knowledge, this is the first study to investigate salivary radiation metabolomics, although different salivary parameters, such as electrolytes and amylase, have been investigated by others (13, 19). Salivary biomarkers have successfully discriminated patients with oral cancer, periodontal disease, breast cancer and pancreatic cancer from healthy controls (20).…”

“…In this pilot study, we extended our studies to assess the utility of saliva as a biofluid for biodosimetry through metabolomics at day 1 and 7 postirradiation, time points that have been previously investigated with other biofluids (1, 4, 6, 7, 9–11). Since the salivary glands as well as oral mucosa are highly radiosensitive, this can be translated in products of radiation exposure directly present in saliva from cells undergoing cell death (12, 13). Reduction in saliva flow has been observed within the first week of radiation exposure and is a severe symptom that is associated in particular with radiotherapy patients undergoing treatment for head and neck cancers.…”

Metabolomic applications in radiation biodosimetry: exploring radiation effects through small molecules

“…Salivary glands and the oral mucosa are highly radiosensitive tissues (Moore et al, 2014), resulting in severe reduction to saliva production within the first week post-exposure that can lead to mucositis, dysphagia, and nutrient malabsorption (Grundmann et al, 2009, Pernot et al, 2014). Differences in electrolytes and enzymes such as amylase have already been reported to be directly associated with radiation exposure (Pernot et al, 2014, Soni et al, 2016), and salivary biomarkers have provided discriminatory power in various cancers and disease states (Tsuruoka et al, 2013, Mikkonen et al, 2014, Zhang et al, 2014b).…”

“…Differences in electrolytes and enzymes such as amylase have already been reported to be directly associated with radiation exposure (Pernot et al, 2014, Soni et al, 2016), and salivary biomarkers have provided discriminatory power in various cancers and disease states (Tsuruoka et al, 2013, Mikkonen et al, 2014, Zhang et al, 2014b). Its availability and ease in acquisition therefore makes it an attractive biofluid for radiation biodosimetry.…”