Recent Advances in ICP-MS Analysis for Metallomics Research of Heart and Kidney Diseases

Metallomics is an omics study for the purpose of ubiquitously understanding the function and role of trace elements in biological activity. In this report, we introduce two topics of analytical techniques related to metallomics studies. ICP-MS have been widely used for the analysis of trace elements, but spectral interference problems sometimes prevent sensitive and accurate analysis. Although various methods had been invented to overcome the problems, the authors developed a simultaneous analytical method for the quantification of trace elements in blood by using sector-field ICP-MS which is more reliable in avoiding polyatomic interferences. We analyzed 25 elements in the human serum of patients with heart or kidney disease and healthy persons using the developed method, and examined the relationship between trace elements and those diseases by using multivariate data analysis. The results showed serum Se and Mn correlated strongly and those concentrations in heart disease patients were significantly lower than those in healthy persons. In particular, the selenium concentration showed a strong relationship with a cardiac function, such as a left ventricular ejection fraction. On the other hand, serum Cr, Ni, and Mo concentrations were significantly higher in dialysis patients. As described above, our study suggests that the kinetics of the trace elements may be causally related to disease conditions. Secondly, ICP-MS can obtain the positional distribution of trace elements in an analytical sample by combining with a laser ablation technique. Hence, we have also tried to develop a LA-ICP-MS imaging technique for biological samples. The trace-element distributions of a human hair strand and a mouse tissue section could be successfully obtained by one or two-dimensional LA-ICP-MS imaging. Furthermore, a multiplex bio-imaging was also obtained by staining with metal-tagged antibodies. Recent developments in ICP-MS and laser ablation techniques are also described along with the above two topics.