Cerebrospinal fluid/plasma quotients of essential and non-essential metals in patients with Alzheimer's disease

In this study, the quotients (Q) between metal concentrations in cerebrospinal fluid (CSF) and plasma were studied in subjects with Alzheimer's disease (AD) and referents to investigate if the leakage through the blood-CSF barrier (BCB) increased with increased duration and severity of the disease. Concentrations of 18 metals (Mg, Ca, Mn, Fe, Co, Ni, Cu, Zn, Se, Rb, Sr, Mo, Cd, Sn, Sb, Cs, Hg, and Pb) were determined by ICP-MS in plasma and cerebrospinal fluid in 264 patients with AD, and in 54 healthy referents. The quotients Q (Mn), Q (Rb), Q (Sb), Q (Pb) and Q (Hg) were significantly lower (p a parts per thousand currency sign 0.003) and Q (Co) significantly higher (p a parts per thousand currency sign 0.001) in subjects with AD as compared with the controls. Subjects in a subgroup with more severe AD, showed the same pattern. The metal leakage into CSF did not increase with increased duration and/or severity of the disease. The permeability of BCB varied considerably between the studied metals with low median quotients (Q a parts per thousand currency sign 0.02) for Cd, Cu, Sb, Se and Zn and higher median quotients for Ca (Q similar to 0.5) and Mg (Q similar to 1.3), probably partly depending on differences in size and lipophilicity of metal-carrier complexes and specific carrier mechanisms.