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 <200 ng/ml including blood contaminated samples centrifuged at 2000 × g. When a protease inhibitor cocktail was added to the CSF prior to centrifugation, the DJ-1 concentration was significantly higher. CONCLUSION: Preanalytical factors such as centrifugation and protease inhibition must be carefully controlled when handling CSF for analysis of DJ-1 and other biomarkers, as DJ-1 was influenced by blood contamination, centrifugation and protease activity.

CSF levels of DJ-1 and tau distinguish MSA patients from PD patients and controls.

Differential diagnosis between Parkinson's disease (PD) and multiple system atrophy (MSA) is difficult, particularly at early disease stages, but is important for therapeutic management. The protein DJ-1 is implicated in the pathology of PD but little is known about its involvement in MSA. We aimed to determine the diagnostic value of CSF DJ-1 and tau proteins for discriminating PD and MSA. DJ-1 and total tau levels were quantified in the CSF of 43 PD patients, 23 MSA patients and 30 non-neurological controls matched for age and gender. Patients were part of a study with a 3-year prospective design with extended case-review follow-up of up to 9 years, ensuring maximum accuracy of the clinical diagnosis. Our results showed that CSF DJ-1 levels could distinguish MSA from PD with a 78% sensitivity and 78% specificity (AUC = 0.84). The combination of DJ-1 and tau proteins significantly improved this discrimination to 82% sensitivity and 81% specificity to identify MSA from PD (AUC = 0.92). Our results highlight the potential benefits of a combination of DJ-1 and total tau as biomarkers for differential diagnosis of MSA and PD.

Development of a capillary isoelectric focusing immunoassay to measure DJ-1 isoforms in biological samples.

We report on the development of a novel assay protocol for the separation and detection of charge isoforms of DJ-1 in biological samples by automated capillary isoelectric focusing followed by immunological detection. DJ-1 (PARK7) is considered as a biomarker candidate for Parkinson's disease and may potentially support the differentiation of clinical subtypes of the disease. The new method allows for separation and subsequent relative quantitative comparison of different isoforms of DJ-1 in biological samples. The assay was successfully applied to the analysis of DJ-1 isoform patterns in brains from mice subjected to normal or high-fat diet and revealed statistically significant group differences. Furthermore, in a pooled and concentrated sample of human cerebrospinal fluid that was depleted of albumin and immunoglobulin G, four different charge variants of DJ-1 could be detected. Taken together, the capillary isoelectric focusing immunoassay for DJ-1 represents a promising tool that may ultimately serve in clinical biomarker studies.

Cerebrospinal fluid biomarkers in Parkinson disease.

Clinical diagnosis of Parkinson disease (PD) is difficult in early stages of disease, with high risk of misdiagnosis. The long preclinical phase of PD provides the possibility for early therapeutic intervention once disease-modifying therapies have been developed, but lack of biomarkers for early diagnosis and monitoring of disease progression represents a major obstacle to achievement of this goal. Accordingly, research efforts aimed at identification of novel biomarkers have been increasing in the past 5 years. Cerebrospinal fluid (CSF) is an accessible source of brain-derived proteins, which mirror molecular changes that take place in the CNS. In this Review, we discuss evidence from numerous studies that have focused on identification of candidate CSF biomarkers for PD. Notably, molecular pathways related to α-synuclein, tau and ß-amyloid peptides have received considerable attention. CSF levels of the protein DJ-1 are also of interest, although further investigation of this candidate marker is required. These studies support the usefulness of a combination of various CSF biomarkers of PD to increase diagnostic accuracy during early phases of the disease, and to differentiate PD from other neurodegenerative disorders.

Biochemical premotor biomarkers for Parkinson's disease.

A biomarker is a biological characteristic that is objectively measured and evaluated as an indicator of normal biological or pathologic processes or of pharmacologic responses to a therapeutic intervention. We reviewed the current status of target protein biomarkers (eg, total/oligomeric α-synuclein and DJ-1) in cerebrospinal fluid, as well as on unbiased processes that can be used to discover novel biomarkers. We have also provide details about strategies toward potential populations/models and technologies, including the need for standardized sampling techniques, to pursue the identification of new biochemical markers in the premotor stage of Parkinson's disease in the future.

DJ-1 and αSYN in LRRK2 CSF do not correlate with striatal dopaminergic function.

Previous studies demonstrated decreased levels of DJ-1 and α-synuclein (αSYN) in human cerebrospinal fluid (CSF) in patients with Parkinson's disease (PD), but neither marker correlated with PD severity, raising the possibility that they may be excellent progression markers during early or preclinical phases of PD. Individuals carrying the leucine-rich repeat kinase 2 (LRRK2) gene mutation are at increased risk for PD, and the phenotype of LRRK2 patients is almost identical to sporadic PD. To determine whether dopaminergic dysfunction in the basal ganglia, as determined by positron emission tomography (PET) scans, correlates with CSF levels of DJ-1 and αSYN during preclinical stages, Luminex assays were used to analyze CSF samples from asymptomatic LRRK2 mutation carriers, along with carriers who presented with a clinical diagnosis of PD. The data revealed no statistically significant relationship between PET scan evidence of loss of striatal dopaminergic function and the CSF biomarkers DJ-1 and αSYN, except for a weak correlation between DJ-1 and methylphenidate binding, suggesting that the use of these potential biomarkers on their own to screen LRRK2 gene mutation carriers for PD is not appropriate.

Cerebrospinal fluid biomarkers for Parkinson disease diagnosis and progression.

OBJECTIVE: There is a clear need to develop biomarkers for Parkinson disease (PD) diagnosis, differential diagnosis of Parkinsonian disorders, and monitoring disease progression. We and others have demonstrated that a decrease in DJ-1 and/or α-synuclein in the cerebrospinal fluid (CSF) is a potential index for Parkinson disease diagnosis, but not for PD severity. METHODS: Using highly sensitive and quantitative Luminex assays, we measured total tau, phosphorylated tau, amyloid beta peptide 1-42 (Aß(1-42)), Flt3 ligand, and fractalkine levels in CSF in a large cohort of PD patients at different stages as well as healthy and diseased controls. The utility of these 5 markers was evaluated for disease diagnosis and severity/progression correlation alone, as well as in combination with DJ-1 and α-synuclein. The major results were further validated in an independent cohort of cross-sectional PD patients as well as in PD cases with CSF samples collected longitudinally. RESULTS: The results demonstrated that combinations of these biomarkers could differentiate PD patients not only from normal controls but also from patients with Alzheimer disease (AD) and multiple system atrophy. Particularly, with CSF Flt3 ligand, PD could be clearly differentiated from multiple system atrophy, a disease that overlaps with PD clinically, with excellent sensitivity (99%) and specificity (95%). In addition, we identified CSF fractalkine/Aß(1-42) that positively correlated with PD severity in cross-sectional samples as well as with PD progression in longitudinal samples. INTERPRETATION: We have demonstrated that this panel of 7 CSF proteins could aid in Parkinson disease diagnosis, differential diagnosis, and correlation with disease severity and progression.

Detection of MYCN DNA in the cerebrospinal fluid for diagnosing isolated central nervous system relapse in neuroblastoma.

We present the case of a 1-year-old female with stage-4 neuroblastoma with MYCN amplification; she was treated with five chemotherapy courses, resulting in normalization of elevated serum levels of tumor markers. Complete remission was achieved after allogeneic hematopoietic stem-cell transplantation with reduced-intensity conditioning. Nine months later, however, the tumor relapsed in the central nervous system (CNS). The serum and cerebrospinal fluid (CSF) levels of the tumor markers were normal, but the MYCN copy number was high only in the CSF DNA, suggesting an isolated CNS recurrence. The MYCN copy number in the CSF DNA was reflective of response to treatment.

α-Synuclein and DJ-1 as potential biological fluid biomarkers for Parkinson's Disease.

Parkinson's disease (PD) is the most common form of movement disorder and affects approximately 4% of the population aged over 80 years old. Currently, PD cannot be prevented or cured, and no single diagnostic biomarkers are available. Notably, recent studies suggest that two familial PD-linked molecules, α-synuclein and DJ-1, are present in cerebrospinal fluid (CSF) and that their levels may be altered during the progression of PD. In this regard, sensitive and accurate methods for evaluation of α-synuclein and DJ-1 levels in the CSF and blood have been developed, and the results suggest that the levels of both molecules are significantly decreased in the CSF in patients with PD compared with age-matched controls. Furthermore, specific detection and quantification of neurotoxic oligometric forms of α-synuclein in the blood using enzyme-linked immunosorbent assays might be expected as potential peripheral biomarkers for PD, although further validation is required. Currently, neither α-synuclein nor DJ-1 is satisfactory as a single biomarker for PD, but combinatory evaluation of these biological fluid molecules with other biomarkers and imaging techniques may provide reliable information for diagnosis of PD.

Problems associated with fluid biomarkers for Parkinson's disease.

This article focuses on biochemical markers that may be used in the diagnostics of Parkinson's disease and associated disorders, and to identify early cases and stratify patients into subgroups. We present an updated account of some currently available candidate fluid biomarkers, and discuss their diagnostic performance and limitations. We also discuss some of the general problems with Parkinson's disease biomarkers and possible ways of moving forward. It may be concluded that a diagnostically useful fluid biomarker for Parkinson's disease is yet to be identified. However, some interesting candidates exist and may prove useful in the future, alone or when analyzed together in patterns.

Biomarkers in Parkinson's disease: a funder's perspective.

Therapeutic development in Parkinson's disease is hampered by the paucity of well-validated biomarkers that can assist with diagnosis and/or tracking the progression of the disease. Since its inception, the Michael J Fox Foundation for Parkinson's Research has invested heavily in biomarker research and continues to prioritize discovery and development efforts. This article summarizes the history and evolution of the Michael J Fox Foundation's role in supporting biomarker research and lays out the current challenges in successfully developing markers that can be used to test therapies, while also providing a vision of future funding efforts in Parkinson's disease biomarkers.

DJ-1 forms complexes with mutant SOD1 and ameliorates its toxicity.

Mutations in Cu/Zn superoxide dismutase (SOD1) gene cause familial amyotrophic lateral sclerosis (ALS), which could be attributed to the toxic properties of the misfolded protein, oxidative stress, and mitochondrial dysfunction. DJ-1 - a causative agent of familial Parkinson's disease PARK7 - is responsible for inducing antioxidative reaction. In this study, we showed the up-regulation of DJ-1 protein levels in mutant SOD1 transgenic mice through the lifespan were observed in the motor neurons. We demonstrated biochemically DJ-1 formed complexes with mutant SOD1 in the cell lysates. Furthermore, DJ-1 over-expression resulted in increased cell viability and reduced cell toxicity in mutant SOD1-transfected neuronal cells, because of improvement in apoptotic pathway and reduction in oxidative stress levels. We also evaluated DJ-1 levels in CSF collected from sporadic ALS patients and controls subjects. The CSF DJ-1 levels were significantly higher in patients with sporadic ALS than in control subjects. These results show that DJ-1 may be associated with sporadic and familial ALS pathogenesis. Therefore, insight into the effects of DJ-1 on mutant SOD1-mediated toxicity may provide a therapeutic advance for the treatment of motor neuron degeneration in ALS.

DJ-1 and alpha-synuclein in human cerebrospinal fluid as biomarkers of Parkinson's disease.

Biomarkers are urgently needed for the diagnosis and monitoring of disease progression in Parkinson's disease. Both DJ-1 and alpha-synuclein, two proteins critically involved in Parkinson's disease pathogenesis, have been tested as disease biomarkers in several recent studies with inconsistent results. These have been largely due to variation in the protein species detected by different antibodies, limited numbers of patients in some studies, or inadequate control of several important variables. In this study, the nature of DJ-1 and alpha-synuclein in human cerebrospinal fluid was studied by a combination of western blotting, gel filtration and mass spectrometry. Sensitive and quantitative Luminex assays detecting most, if not all, species of DJ-1 and alpha-synuclein in human cerebrospinal fluid were established. Cerebrospinal fluid concentrations of DJ-1 and alpha-synuclein from 117 patients with Parkinson's disease, 132 healthy individuals and 50 patients with Alzheimer's disease were analysed using newly developed, highly sensitive Luminex technology while controlling for several major confounders. A total of 299 individuals and 389 samples were analysed. The results showed that cerebrospinal fluid DJ-1 and alpha-synuclein levels were dependent on age and influenced by the extent of blood contamination in cerebrospinal fluid. Both DJ-1 and alpha-synuclein levels were decreased in Parkinson's patients versus controls or Alzheimer's patients when blood contamination was controlled for. In the population aged > or = 65 years, when cut-off values of 40 and 0.5 ng/ml were chosen for DJ-1 and alpha-synuclein, respectively, the sensitivity and specificity for patients with Parkinson's disease versus controls were 90 and 70% for DJ-1, and 92 and 58% for alpha-synuclein. A combination of the two markers did not enhance the test performance. There was no association between DJ-1 or alpha-synuclein and the severity of Parkinson's disease. Taken together, this represents the largest scale study for DJ-1 or alpha-synuclein in human cerebrospinal fluid so far, while using newly established sensitive Luminex assays, with controls for multiple variables. We have demonstrated that total DJ-1 and alpha-synuclein in human cerebrospinal fluid are helpful diagnostic markers for Parkinson's disease, if variables such as blood contamination and age are taken into consideration.

Correlation between DJ-1 levels in the cerebrospinal fluid and the progression of disabilities in multiple sclerosis patients.

OBJECTIVES: DJ-1 plays a key role in the anti-oxidative stress function. Increasing evidence supports the role of oxidative stress in the pathogenesis of multiple sclerosis (MS). The aim of this study was to investigate whether the DJ-1 levels were increased in patients with MS and to examine its association with the progression of MS. METHODS: Quantitative immunoblot assays were performed to evaluate the DJ-1 level in serum and cerebrospinal fluid (CSF) collected from relapsing-remitting patients with MS (n = 29), disease controls subjects (n = 14), and healthy subjects (n = 44). RESULTS: No significant difference was observed in the serum DJ-1 level among the patients with MS, disease controls, and healthy controls. However, the CSF DJ-1 levels were significantly higher in the patients with MS than in the disease control subjects (P < 0.0001). A significant positive correlation was also found between the CSF DJ-1 levels and the Multiple Sclerosis Severity Score (P < 0.005, r = 0.501). CONCLUSIONS: These results show that the CSF DJ-1 levels are significantly increased in the CSF of patients with MS and that the CSF DJ-1 levels may be associated with the disease progression of MS. Therefore, DJ-1 possibly plays an important role in the pathogenesis of MS.

Increased level of DJ-1 in the cerebrospinal fluids of sporadic Parkinson's disease.

DJ-1 is an antioxidant protein whose loss of function by gene mutations has been linked to familial Parkinson's disease (PD). The main objective of the present study was to determine if this molecule was also involved in the pathogenesis of sporadic PD. For this purpose, quantitative immunoblot assays were performed to evaluate DJ-1 in cerebrospinal fluids (CSF) collected from sporadic PD patients (n=40) and non-PD controls (n=38). The results showed that the CSF DJ-1 levels in PD were significantly higher than those in non-PD controls. Especially, upregulation of CSF DJ-1 in the early stage of PD (Yahr I-II) were distinct compared to those in the advanced stage of PD (Yahr III-IV) and non-PD controls (p<0.001 by ANOVA with post hoc Bonferroni's test), suggesting a protective role of DJ-1 against oxidative stress during the early stage. Thus, we propose that CSF DJ-1 could be a possible biomarker for early sporadic PD.

PARK7 and nucleoside diphosphate kinase A as plasma markers for the early diagnosis of stroke.

BACKGROUND: Plasma markers for stroke could be useful in diagnosis and prognosis and in prediction of response of stroke patients to therapy. PARK7 and nucleoside diphosphate kinase A (NDKA) are increased in human postmortem cerebrospinal fluid (CSF), a model of global brain insult, suggesting that measurement in CSF and, more importantly, in plasma may be useful as a biomarker of stroke. METHODS: We used ELISA to measure PARK7 and NDKA in plasma in 3 independent European and North American retrospective studies encompassing a total of 622 stroke patients and 165 control individuals. RESULTS: Increases in both biomarkers were highly significant, with sensitivities of 54%-91% for PARK7 and 70%-90% for NDKA and specificities of 80%-97% for PARK7 and 90%-97% for NDKA. The concentrations of both biomarkers increased within 3 h of stroke onset. CONCLUSIONS: PARK7 and NDKA may be useful plasma biomarkers for the early diagnosis of stroke. In addition, this study demonstrated the utility of analysis of postmortem CSF proteins as a first step in the discovery of plasma markers of ischemic brain injury.