Selenium speciation analysis in the cerebrospinal fluid of patients with Parkinson's disease.
BACKGROUND
The aim of the study was to investigate if speciation analysis by liquid chromatography coupled to mass spectrometry could be used to detect organic and inorganic binding forms of selenium in the cerebrospinal fluid (CSF) of patients with Parkinson's disease (PD) and age-matched control subjects (AMC).


METHODS
PD patients and control subjects were enrolled from three different neurological departments. CSF samples were collected according to standardized biomarker protocols and subjected to inductively coupled plasma mass spectrometry (ICP-MS) for total selenium determination and ion exchange chromatography (IEC) hyphenated to ICP-MS for selenium speciation analysis.


RESULTS
75 PD patients and 68 age-matched controls were enrolled for speciation analysis. 8 different species could be detected, but only selenoprotein P (SELENOP), human serum albumin-bound Se (Se-HSA), selenomethionine (Se-Met) and an unidentified Se-compound (U2) presented with more than 50% values above the limit of quantification, without showing significant differences between both groups (p > 0.05). The Se-HSA / Se-Met ratio yielded a significant difference between PD and AMC (p = 0.045). The inorganic species Se-IV and Se-VI were only detectable in a minor part of PD and AMC samples. A highly significant correlation between total selenium levels and SELENOP (PD p < 0.0001; AMC p < 0.0001) and Se-HSA (PD p < 0.0001; AMC p < 0.0001) could be demonstrated, respectively.


CONCLUSIONS
Speciation analysis yielded new insight into selenium homeostasis in PD but cannot be used to establish a diagnostic biomarker. The small number of detectable values for Se-IV and Se-VI suggests an inferior role of these potentially neurotoxic binding forms in PD pathology in contrast to other neurodegenerative disorders.
['Maass|Fabian|F|', 'Michalke|Bernhard|B|', 'Willkommen|Desiree|D|', 'Schulte|Claudia|C|', 'Tönges|Lars|L|', 'Boerger|Matthias|M|', 'Zerr|Inga|I|', 'Bähr|Mathias|M|', 'Lingor|Paul|P|']
D000368:Aged D006801:Humans D013058:Mass Spectrometry D008875:Middle Aged D010300:Parkinson Disease D012643:Selenium D018036:Selenium Compounds D012645:Selenomethionine D051149:Selenoprotein P
Selenium Speciation analysis Cerebrospinal fluid Parkinson’s disease