Preliminary Communication For reprint orders, please contact: [email protected]
The influence of preanalytical conditions on the DJ-1 concentration in human cerebrospinal fluid
Aim: The purpose of this study was to establish the influence of centrifugation and protease activity on the cerebrospinal fluid (CSF) concentrations of DJ-1 and hemoglobin. Materials & methods: The concentrations of DJ-1 and hemoglobin were determined in 12 (DJ-1) and six (hemoglobin) pairs of CSF samples, with one sample being stored without centrifugation and the other being centrifuged at 2000 × g before storage. The DJ-1 concentration was also determined in centrifuged and uncentrifuged CSF containing protease inhibitors and compared with values determined in centrifuged and uncentrifuged CSF samples without protease inhibitors. Furthermore, specific protein concentrations were determined in CSF from two groups, each comprising 23 patients with Parkinson’s disease. In one group the CSF was centrifuged at 1300−1800 × g, 4°C, 10 min, and in the other at 2000 × g, 4°C, 10 min. Results: Centrifugation at 2000 × g resulted in significantly lower CSF DJ-1 concentrations compared with no centrifugation and centrifugation at a lower g-force. There was a significant difference in the hemoglobin concentration between centrifuged and uncentrifuged CSF. In all centrifuged samples the hemoglobin concentration was 10 years). All CSF samples in both groups were centrifuged to ensure removal of erythrocytes (and hereby the possible source of cellular DJ-1) before storing. The four above mentioned differences in preanalytical conditions may contribute to the observed difference in the CSF DJ-1. As the quantitative aspects of this potential influence are unknown, future studies comparing CSF samples from the same patient centrifuged at different RCFs are needed to verify our results.
Preliminary Communication
Conclusion & future perspective In conclusion, our data show that CSF DJ-1 is influenced by blood contamination and centrifugation. Although many other preanalytical issues still need to be addressed, this indicates that preanalytical factors such as centrifugation and protease inhibition must be carefully controlled when handling CSF samples for analysis of DJ-1 and other biomarkers. We recommend centrifugation at 2000 × g for 10 min, rapid handling and storage at -80°C. Our data indicate that the CSF proteases may affect the DJ-1 level. Further studies on larger cohorts are needed to estimate the quantitative aspects of this factor. Financial & competing interests disclosure The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties. No writing assistance was utilized in the production of this manuscript.
Ethical conduct of research The authors state that they have obtained appropriate institutional review board approval and have followed the principles outlined in the Declaration of Helsinki for all human experimental investigations. In addition, for investigations involving human subjects, informed consent has been obtained from the participants involved.
Executive summary Role of centrifugation • Cerebrospinal fluid (CSF) DJ-1 is influenced by blood contamination and centrifugation. • Centrifugation of CSF at a relative centrifugal force of 2000 × g, for 10 min reduces hemoglobin levels to
The influence of preanalytical conditions on the DJ-1 concentration in human cerebrospinal fluid
Aim: The purpose of this study was to establish the influence of centrifugation and protease activity on the cerebrospinal fluid (CSF) concentrations of DJ-1 and hemoglobin. Materials & methods: The concentrations of DJ-1 and hemoglobin were determined in 12 (DJ-1) and six (hemoglobin) pairs of CSF samples, with one sample being stored without centrifugation and the other being centrifuged at 2000 × g before storage. The DJ-1 concentration was also determined in centrifuged and uncentrifuged CSF containing protease inhibitors and compared with values determined in centrifuged and uncentrifuged CSF samples without protease inhibitors. Furthermore, specific protein concentrations were determined in CSF from two groups, each comprising 23 patients with Parkinson’s disease. In one group the CSF was centrifuged at 1300−1800 × g, 4°C, 10 min, and in the other at 2000 × g, 4°C, 10 min. Results: Centrifugation at 2000 × g resulted in significantly lower CSF DJ-1 concentrations compared with no centrifugation and centrifugation at a lower g-force. There was a significant difference in the hemoglobin concentration between centrifuged and uncentrifuged CSF. In all centrifuged samples the hemoglobin concentration was 10 years). All CSF samples in both groups were centrifuged to ensure removal of erythrocytes (and hereby the possible source of cellular DJ-1) before storing. The four above mentioned differences in preanalytical conditions may contribute to the observed difference in the CSF DJ-1. As the quantitative aspects of this potential influence are unknown, future studies comparing CSF samples from the same patient centrifuged at different RCFs are needed to verify our results.
Preliminary Communication
Conclusion & future perspective In conclusion, our data show that CSF DJ-1 is influenced by blood contamination and centrifugation. Although many other preanalytical issues still need to be addressed, this indicates that preanalytical factors such as centrifugation and protease inhibition must be carefully controlled when handling CSF samples for analysis of DJ-1 and other biomarkers. We recommend centrifugation at 2000 × g for 10 min, rapid handling and storage at -80°C. Our data indicate that the CSF proteases may affect the DJ-1 level. Further studies on larger cohorts are needed to estimate the quantitative aspects of this factor. Financial & competing interests disclosure The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties. No writing assistance was utilized in the production of this manuscript.
Ethical conduct of research The authors state that they have obtained appropriate institutional review board approval and have followed the principles outlined in the Declaration of Helsinki for all human experimental investigations. In addition, for investigations involving human subjects, informed consent has been obtained from the participants involved.
Executive summary Role of centrifugation • Cerebrospinal fluid (CSF) DJ-1 is influenced by blood contamination and centrifugation. • Centrifugation of CSF at a relative centrifugal force of 2000 × g, for 10 min reduces hemoglobin levels to
