Buccal cells: a non-invasive measurement of selenium, zinc and magnesium status, and telomere length.

Background – There is a need to develop minimally invasive methodologies to measure changes in tissue nutrient levels and alterations in disease risk biomarkers. Objective – We aimed to evaluate the use of buccal cells as a non-invasive approach to measure nutrient levels (selenium, zinc and magnesium) and markers of oxidative stress and accelerated ageing (telomere length) in crosssectional study. Design – Buccal cells and blood samples were collected from 91 volunteers. This cohort comprised 18M and 25F in the young group (aged 18-31 years), and 25M and 23F in the older group (65-75yrs). Se, Zn, Mg and Ca were measured in serum and buccal cells (by ICPMS and ICPOES). Telomere length measures were determined in lymphocytes and buccal cells (by Flow and qRTm-PCR). Outcomes – Only Se levels were significantly correlated in serum and buccal cell samples (r=0.3, p<0.01). Serum Ca was negatively correlated with buccal cell Ca (r=-0.25, p<0.01). There were significant correlations of age with: serum Se (r=0.27, p<0.01) and buccal Ca (r=0.24, p<0.05), buccal Se (r=0.28, p<0.01). Telomere length correlated negatively with age in lymphocytes (r=-0.28, p<0.01) and positively with age in the buccal cells (r=0.22, p<0.05). Conclusions -–Trace elements and telomere length can be measured in buccal samples. However, with the exception of Se, results in cells were not positively correlated with each other. These data indicate that the measurements in plasma and buccal samples are not interchangeable. The positive correlation of telomere length with age in buccal cells indicates a strong difference from lymphocytes and suggests differences in telomere length dynamics in the haematopoietic and epithelial tissue.