Trace elements in scalp hair and fingernails as biomarkers in clinical studies

Abstract

Context: There are accumulating evidences that the metabolism of several trace elements might have specific roles in clinical disorders and the pathogenesis of many diseases, such as diabetes mellitus (DM) and hypertension (HT). Objectives: To validate the analytical procedure and compare the levels of Cd, Cr, Cu, Pb, and Zn in scalp hair (SH) and fingernails (FN) of patients. Furthermore, to prove that human tissues such as hair and nails are useful in the studies pertaining to chronic body exposure and good biomarkers in clinical studies. Setting and Design: Inductively coupled plasma optical emission spectroscopy operating conditions were carefully selected and well-optimised in order to maximise the sensitivity for the desired elements and to obtain the best precision and accuracy. Factors affecting analytical and biological variability of the concentrations under study were discussed and carefully optimised. Materials and Methods: Totally, 160 samples of SH and 130 FN were collected from occupants of urban population from different districts adjacent to Taif city, Kingdom of Saudi Arabia. Different analytical procedures were investigated, and the most reliable one was developed and validated. Method Validity: The validity of the method was checked by standard addition method. The recoveries were in the range of 96.2-105.7%. Results: Cd, Cr, Cu, and Pb levels in SH were significantly higher in DM and HT compared to control groups, whereas, Zn was significantly lower. Cd and Pb levels in FN were significantly higher in DM and HT, whereas, Cr and Zn were lower, and Cu was in the same levels as compared to the control group. Conclusion: These findings may be consistent with those obtained in other studies, confirming that the deficiency and efficiency of trace elements play a role in clinical disorders and the pathogenesis of many diseases.