Apolipoprotein D: a potential biomarker for cerebral amyloid angiopathy.

AIMS: We investigated the potential of apolipoprotein D (apoD) as cerebrospinal fluid (CSF) biomarker for cerebral amyloid angiopathy (CAA) after confirmation of its association with CAA pathology in human brain tissue. METHODS: The association of apoD with CAA pathology was analysed in human occipital lobe tissue of CAA (n = 9), Alzheimer's disease (AD) (n = 11) and healthy control cases (n = 11). ApoD levels were quantified in an age- and sex-matched CSF cohort of CAA patients (n = 31), AD patients (n = 27) and non-neurological controls (n = 67). The effects of confounding factors (age, sex, serum levels) on apoD levels were studied using CSF of non-neurological controls (age range 16-85 years), and paired CSF and serum samples. RESULTS: ApoD was strongly associated with amyloid deposits in vessels, but not with parenchymal plaques in human brain tissue. CSF apoD levels correlated with age and were higher in men than women in subjects >50 years. The apoD CSF/serum ratio correlated with the albumin ratio. When controlling for confounding factors, CSF apoD levels were significantly lower in CAA patients compared with controls and compared with AD patients (P = 0.0008). CONCLUSIONS: Our data show that apoD is specifically associated with CAA pathology and may be a CSF biomarker for CAA, but clinical application is complicated due to dependency on age, sex and blood-CSF barrier integrity. Well-controlled follow-up studies are required to determine whether apoD can be used as reliable biomarker for CAA.

Downregulation of synapse-associated protein expression and loss of homeostatic microglial control in cerebrospinal fluid of infectious patients with delirium and patients with Alzheimer's disease.

Delirium is a complex and multifactorial condition associated with long-term cognitive decline. Due to the strong links between systemic inflammation, delirium and dementia we hypothesized that responses within the brain in patients who develop delirium could show biochemical overlap with patients with Alzheimer's disease (AD). In this observational study we analyzed protein expression signatures in cerebrospinal fluid (CSF) from 15 patients with infectious delirium and compared these to 29 patients with AD, 30 infectious patients without delirium and 15 non-infectious controls free of neurological disease. A proximity extension assay was performed measuring a total of 184 inflammatory and neurology-related proteins. Eight inflammatory proteins (4%), including the key neuron-microglia communication marker CX3CL1 (fractalkine), were significantly upregulated in both delirium and AD, compared to infectious patients without delirium. Likewise, 23 proteins (13%) showed downregulation in both delirium and AD, relative to infectious patients without delirium, which interestingly included CD200R1, another neuron-microglia communication marker, as well as a cluster of proteins related to synapse formation and function. Synaptopathy is an early event in AD and correlates strongly with cognitive dysfunction. These results were partially mediated by aging, which is an important predisposing risk factor among many others for both conditions. Within this study we report the first in vivo human evidence suggesting that synapse pathology and loss of homeostatic microglial control is involved in the pathophysiology of both infectious delirium and AD and thus may provide a link for the association between infections, delirium and long-term cognitive decline.

The Personalized Parkinson Project: examining disease progression through broad biomarkers in early Parkinson's disease.

BACKGROUND: Our understanding of the etiology, pathophysiology, phenotypic diversity, and progression of Parkinson's disease has stagnated. Consequently, patients do not receive the best care, leading to unnecessary disability, and to mounting costs for society. The Personalized Parkinson Project (PPP) proposes an unbiased approach to biomarker development with multiple biomarkers measured longitudinally. Our main aims are: (a) to perform a set of hypothesis-driven analyses on the comprehensive dataset, correlating established and novel biomarkers to the rate of disease progression and to treatment response; and (b) to create a widely accessible dataset for discovery of novel biomarkers and new targets for therapeutic interventions in Parkinson's disease. METHODS/DESIGN: This is a prospective, longitudinal, single-center cohort study. The cohort will comprise 650 persons with Parkinson's disease. The inclusion criteria are purposely broad: age ≥ 18 years; and disease duration ≤5 years. Participants are followed for 2 years, with three annual assessments at the study center. Outcomes include a clinical assessment (including motor and neuro-psychological tests), collection of biospecimens (stool, whole blood, and cerebrospinal fluid), magnetic resonance imaging (both structural and functional), and ECG recordings (both 12-lead and Holter). Additionally, collection of physiological and environmental data in daily life over 2 years will be enabled through the Verily Study Watch. All data are stored with polymorphic encryptions and pseudonyms, to guarantee the participants' privacy on the one hand, and to enable data sharing on the other. The data and biospecimens will become available for scientists to address Parkinson's disease-related research questions. DISCUSSION: The PPP has several distinguishing elements: all assessments are done in a single center; inclusion of "real life" subjects; deep and repeated multi-dimensional phenotyping; and continuous monitoring with a wearable device for 2 years. Also, the PPP is powered by privacy and security by design, allowing for data sharing with scientists worldwide respecting participants' privacy. The data are expected to open the way for important new insights, including identification of biomarkers to predict differences in prognosis and treatment response between patients. Our long-term aim is to improve existing treatments, develop new therapeutic approaches, and offer Parkinson's disease patients a more personalized disease management approach. TRIAL REGISTRATION: Clinical Trials NCT03364894 . Registered December 6, 2017 (retrospectively registered).

Soluble TLR2 and 4 concentrations in cerebrospinal fluid in HIV/SIV-related neuropathological conditions.

HIV in the central nervous system (CNS) mainly infects microglial cells which are known to express toll-like receptors (TLRs). This paper aimed to study the role of soluble TLR2 (sTLR2), sTLR4, and other inflammatory markers in cerebrospinal fluid (CSF) in HIV/Simian immunodeficiency virus (SIV)-related neurological sequelae. We determined sTLR2 and sTLR4 levels in CSF and serum/plasma of SIV-infected rhesus macaques with and without neurological sequelae, as well as in HIV-infected patients with and without cognitive impairments and Alzheimer's disease (AD) patients and matched controls. CSF cytokines and chemokines levels were analyzed in macaques as markers of neuroinflammation, while neopterin and S100B CSF concentrations were measured in HIV-infected patients as microglial and astrocyte marker, respectively. We found detectable levels of sTLR2 and sTLR4 in CSF of macaques and humans. Furthermore, CSF sTLR2 and sTLR4 concentrations were higher in SIV-infected macaques with neurological sequelae compared to those without neurological complications (p = 0.0003 and p = 0.0006, respectively). CSF IL-8 and monocyte chemoattractant protein-1 (MCP-1) levels were elevated in macaques with neurological sequelae, and a positive correlation was found between CSF levels of sTLR2/4 and IL-8 and MCP-1. Also in humans, elevated CSF sTLR4 levels were found in HIV-infected patients with cognitive impairments compared to HIV-infected patients with normal cognition (p = 0.019). Unlike CSF S100B levels, neopterin correlated positively with sTLR2 and sTLR4. No difference was found in plasma and CSF sTLR2 and sTLR4 levels between AD patients and control subjects (p = 0.26). In conclusion, CSF sTLR2 and sTLR4 may play a role in HIV/SIV-related neuroinflammation and subsequent neuropathology.

Structural biomarkers in the cerebrospinal fluid within 24 h after a traumatic spinal cord injury: a descriptive analysis of 16 subjects.

STUDY DESIGN: Prospective cohort study. OBJECTIVES: To characterize the cerebrospinal fluid (CSF) concentrations of glial fibrillary acidic protein, neuron specific enolase (NSE), S-100ß, tau and neurofilament heavy chain (NFH) within 24 h of an acute traumatic spinal cord injury (SCI), and to correlate these concentrations with the baseline severity of neurologic impairment as graded by the American Spinal Injury Association impairment scale (AIS). METHODS: A lumbar puncture was performed to obtain CSF from 16 acute traumatic SCI patients within 24 h post injury. Neurological examinations were performed within 24 h of injury and again at 6 or 12 months post injury. The correlations between the CSF concentrations and initial AIS were calculated by using Pearson correlation coefficients. In addition, an independent Student's t-test was used to test for differences in CSF concentrations between patients of different AIS grades. RESULTS: The CSF NSE concentrations were significantly correlated with the baseline neurologic impairment being either 'motor complete' (AIS A, B) or 'motor incomplete' (AIS C, D) (r=0.520, P<0.05). The mean S-100ß concentration in motor complete patients was significantly higher compared with motor incomplete patients; 377.2 µg l(-1) (s.d.±523 µg l(-1)) vs 57.1 µg l(-1) (s.d.±56 µg l(-1)) (P<0.05), respectively. Lastly, the mean NFH concentration in motor complete patients was significantly higher compared with motor incomplete patient, 11 813 ng l(-1) (s.d.±16 195 ng l(-1)) vs 1446.8 ng l(-1) (s.d.±1533 ng l(-1)), (P<0.05), respectively. CONCLUSION: In this study we identified differences in the structural CSF biomarkers NSE, S-100ß and NFH between motor complete and motor incomplete SCI patients. Our data showed no clear differences in any of the protein concentrations between the different AIS grades.

Anxiety is related to Alzheimer cerebrospinal fluid markers in subjects with mild cognitive impairment.

BACKGROUND: Anxiety, apathy and depression are common in subjects with mild cognitive impairment (MCI) and may herald Alzheimer's disease (AD). We investigated whether these symptoms correlated with cerebrospinal fluid (CSF) markers for AD in subjects with MCI. Method Subjects with MCI (n=268) were selected from the 'Development of screening guidelines and criteria for pre-dementia Alzheimer's disease' (DESCRIPA) and Alzheimer's Disease Neuroimaging Initiative (ADNI) studies. We measured amyloid ß(1-42) protein (Aß42) and total tau (t-tau) in CSF. Neuropsychiatric symptoms were measured with the Neuropsychiatric Inventory. RESULTS: Depressive symptoms were reported by 55 subjects (21%), anxiety by 35 subjects (13%) and apathy by 49 subjects (18%). The presence of anxiety was associated with abnormal CSF Aß42 [odds ratio (OR) 2.3, 95% confidence interval (CI) 1.6-3.3] and t-tau (OR 2.6, 95% CI 1.9-3.6) concentrations and with the combination of abnormal concentrations of both Aß42 and t-tau (OR 3.1, 95% CI 2.0-4.7). The presence of agitation and irritability was associated with abnormal concentrations of Aß42 (agitation: OR 1.6, 95% CI 1.1-2.3; irritability: OR 2.2, 95% CI 1.5-3.3). Symptoms of depression and apathy were not related to any of the CSF markers. CONCLUSIONS: In subjects with MCI, symptoms of anxiety, agitation and irritability may reflect underlying AD pathology, whereas symptoms of depression and apathy do not.

Minocycline for sporadic and hereditary cerebral amyloid angiopathy (BATMAN): study protocol for a placebo-controlled randomized double-blind trial.

BACKGROUND: Cerebral amyloid angiopathy (CAA) is a disease caused by the accumulation of the amyloid-beta protein and is a major cause of intracerebral hemorrhage (ICH) and vascular dementia in the elderly. The presence of the amyloid-beta protein in the vessel wall may induce a chronic state of cerebral inflammation by activating astrocytes, microglia, and pro-inflammatory substances. Minocycline, an antibiotic of the tetracycline family, is known to modulate inflammation, gelatinase activity, and angiogenesis. These processes are suggested to be key mechanisms in CAA pathology. Our aim is to show the target engagement of minocycline and investigate in a double-blind placebo-controlled randomized clinical trial whether treatment with minocycline for 3 months can decrease markers of neuroinflammation and of the gelatinase pathway in cerebrospinal fluid (CSF) in CAA patients. METHODS: The BATMAN study population consists of 60 persons: 30 persons with hereditary Dutch type CAA (D-CAA) and 30 persons with sporadic CAA. They will be randomized for either placebo or minocycline (15 sporadic CAA/15 D-CAA minocycline, 15 sporadic CAA/15 D-CAA placebo). At t = 0 and t = 3 months, we will collect CSF and blood samples, perform a 7-T MRI, and collect demographic characteristics. DISCUSSION: The results of this proof-of-principle study will be used to assess the potential of target engagement of minocycline for CAA. Therefore, our primary outcome measures are markers of neuroinflammation (IL-6, MCP-1, and IBA-1) and of the gelatinase pathway (MMP2/9 and VEGF) in CSF. Secondly, we will look at the progression of hemorrhagic markers on 7-T MRI before and after treatment and investigate serum biomarkers. TRIAL REGISTRATION: ClinicalTrials.gov NCT05680389. Registered on January 11, 2023.

Genome-wide identification of Streptococcus pneumoniae genes essential for bacterial replication during experimental meningitis.

Meningitis is the most serious of invasive infections caused by the Gram-positive bacterium Streptococcus pneumoniae. Vaccines protect only against a limited number of serotypes, and evolving bacterial resistance to antimicrobials impedes treatment. Further insight into the molecular pathogenesis of invasive pneumococcal disease is required in order to enable the development of new or adjunctive treatments and/or pneumococcal vaccines that are efficient across serotypes. We applied genomic array footprinting (GAF) in the search for S. pneumoniae genes that are essential during experimental meningitis. A total of 6,000 independent TIGR4 marinerT7 transposon mutants distributed over four libraries were injected intracisternally into rabbits, and cerebrospinal fluid (CSF) was collected after 3, 9, and 15 h. Microarray analysis of mutant-specific probes from CSF samples and inocula identified 82 and 11 genes mutants of which had become attenuated or enriched, respectively, during infection. The results point to essential roles for capsular polysaccharides, nutrient uptake, and amino acid biosynthesis in bacterial replication during experimental meningitis. The GAF phenotype of a subset of identified targets was followed up by detailed studies of directed mutants in competitive and noncompetitive infection models of experimental rat meningitis. It appeared that adenylosuccinate synthetase, flavodoxin, and LivJ, the substrate binding protein of a branched-chain amino acid ABC transporter, are relevant as targets for future therapy and prevention of pneumococcal meningitis, since their mutants were attenuated in both models of infection as well as in competitive growth in human cerebrospinal fluid in vitro.

Cerebrospinal fluid tau and phosphorylated tau protein are elevated in corticobasal syndrome.

Differentiating corticobasal syndrome (CBS) from progressive supranuclear palsy (PSP) and idiopathic Parkinson's disease (PD) can be difficult. To investigate the additional value of cerebrospinal fluid (CSF) biomarkers in the diagnostic differentiation of parkinsonism, we analyzed the CSF concentrations of total protein, lactate and brain specific proteins amyloid-ß(42) protein, tau protein (t-tau), and tau protein phosphorylated at Thr181 (p-tau), in CSF samples from patients with PSP (n = 21), CBS (n = 12), and PD (n = 28). CBS patients demonstrated higher concentrations of t-tau and p-tau compared with PSP and PD patients. In discriminating CBS and PD, t-tau offered the best combination of sensitivity (75%) and specificity (90.9%), followed by p-tau (sensitivity 87.5% and specificity 75%). The p-tau/t-tau ratio resulted in sensitivity of 84.2% and specificity of 66.7% in discriminating PSP and CBS. In conclusion, our results suggest that CSF parameters are of additional value in the diagnostic differentiation of CBS and PD.

Neurofilament light chain: A novel blood biomarker in patients with ataxia telangiectasia.

AIM: Neurofilament light chain (NfL) is recognized as a blood biomarker in several neurodegenerative disorders, but its possible relevance in Ataxia Telangiectasia (A-T) has not been examined. The aim of this study was to investigate the biomarker potential of blood NfL concentrations in patients with A-T. METHOD: Blood (serum/plasma) NfL concentrations were measured in a Dutch and an American cohort of patients with A-T and compared to control values. Additionally, correlations between NfL concentrations and disease phenotype (classic versus variant A-T) were studied. RESULTS: In total 40 (23 Dutch and 17 American) patients with A-T (32 patients with classic A-T and 7 patients with variant A-T) and 17 age- and gender-matched (to the American cohort) healthy controls were included in this study. Blood (serum/plasma) NfL concentrations in patients with classic A-T and age ≤ 12 years were elevated compared to age matched controls. Patients with classic A-T > 12 years also had higher blood (serum/plasma) NfL concentrations (here: compared to age-dependent reference values found in the literature). Patients with classic A-T had higher blood (serum/plasma) NfL concentrations than patients with the variant phenotype. CONCLUSION: Blood (serum/plasma) NfL concentrations are elevated in patients with classic A-T and appear to correlate with the disease phenotype (classic versus variant). Therefore, blood (serum/plasma) NfL may be a promising biomarker in A-T.

Urinary dopamine in aromatic L-amino acid decarboxylase deficiency: the unsolved paradox.

INTRODUCTION: In aromatic L-amino acid decarboxylase (AADC) deficiency, a neurotransmitter biosynthesis defect, paradoxical normal or increased levels of urinary dopamine have been reported. Genotype/phenotype correlations or alternative metabolic pathways may explain this remarkable finding, but were never studied systematically. METHODS: We studied the mutational spectrum and urinary dopamine levels in 20 patients with AADC-deficiency. Experimental procedures were designed to test for alternative metabolic pathways of dopamine production, which included alternative substrates (tyramine and 3-methoxytyrosine) and alternative enzymes (tyrosinase and CYP2D6). RESULTS/DISCUSSION: In 85% of the patients the finding of normal or increased urinary levels of dopamine was confirmed, but a relation with AADC genotype could not be identified. Renal microsomes containing CYP2D were able to convert tyramine into dopamine (3.0 nmol/min/g protein) but because of low plasma levels of tyramine this is an unlikely explanation for urinary dopamine excretion in AADC-deficiency. No evidence was found for the production of dopamine from 3-methoxytyrosine. Tyrosinase was not expressed in human kidney. CONCLUSION: Normal or increased levels of urinary dopamine are found in the majority of AADC-deficient patients. This finding can neither be explained by genotype/phenotype correlations nor by alternative metabolic pathways, although small amounts of dopamine may be formed via tyramine hydroxylation by renal CYP2D6. CYP2D6-mediated conversion of tyramine into dopamine might be an interesting target for the development of new therapeutic strategies in AADC-deficiency.

Limited expression of heparan sulphate proteoglycans associated with Aß deposits in the APPswe/PS1dE9 mouse model for Alzheimer's disease.

AIMS: Alzheimer's disease (AD) is characterized by deposition of the amyloid beta (Aß) peptide in brain parenchyma and vasculature. Several proteins co-deposit with Aß, including heparan sulphate proteoglycans (HSPG). HSPG have been suggested to contribute to Aß aggregation and deposition, and may influence plaque formation and persistence by stimulating Aß fibrillization and by protecting Aß against degradation. Mouse models for AD, expressing the human amyloid precursor protein (APP), produce Aß deposits similar to humans. These models may be used to study disease pathology and to develop new therapeutic interventions. We aimed to investigate whether co-deposition of HSPG in AD brains can be replicated in the APPswe/PS1dE9 mouse model for AD and if a temporal association of HSPG with Aß exists. METHODS: We studied the co-deposition of several HSPG and of the glycosaminoglycan side chains of HSPG in the APPswe/PS1dE9 model at different ages by immunohistochemistry. RESULTS: We found that, although APPswe/PS1dE9 mice did develop severe Aß pathology with age, co-deposition of HS glycosaminoglycan chains and the various HSPG (agrin, perlecan and glypican-1) was scarce (<10-30% of the Aß deposits were stained). CONCLUSIONS: Our data suggest that the molecular composition of Aß deposits in the APPswe/PS1dE9 mouse, with respect to the several HSPG investigated in this study, does not accurately reflect the human situation. The near absence of HSPG in Aß deposits in this transgenic mouse model may, in turn, hinder the translation of preclinical intervention studies from mice to men.

Increased cerebrospinal fluid chitotriosidase index in patients with multiple sclerosis.

OBJECTIVE: To investigate chitotriosidase (CTTS) activity in serum and cerebrospinal fluid (CSF) in multiple sclerosis (MS) patients in relation to disease course and CSF markers for immune activation or inflammation. MATERIALS AND METHODS: We studied 80 patients with relapsing-remitting MS (RRMS), 24 with secondary progressive MS (SPMS), 20 with primary progressive MS (PPMS) and 29 patients with other neurological disorders (OND). We measured CTTS activity and studied the correlation with CSF mononuclear cell count (MNC) and intrathecal IgG production. RESULTS: CTTS activity was significantly higher in CSF, but not in serum, from the total MS group compared with OND and controls. In RRMS and SPMS CTTS, index was increased compared with controls (RRMS, 0.10 +/- 0.21; SPMS, 0.10 +/- 0.15; controls, 0.021 +/- 0.020), but not in PPMS (0.061 +/- 0.052). CTTS index was higher in MS patients with elevated MNC or CSF-restricted oligoclonal IgG bands than in MS patients without these CSF findings. CONCLUSIONS: CTTS index is elevated in RRMS and SPMS. The CTTS index is related to CSF markers of inflammation or immune activation.

Tyrosine hydroxylase deficiency with severe clinical course.

Tyrosine hydroxylase (TH) deficiency is a rare autosomal recessive disorder mapped to chromosome 11p15.5. Its clinical expression varies with presentations as dopa-responsive dystonia (recessive Segawa's disease), dopa-responsive infantile parkinsonism, dopa-responsive spastic paraplegia, progressive infantile encephalopathy or dopa-non-responsive dystonia. We describe a 7-year-old boy with progressive infantile encephalopathy and non-responsiveness to dopamine. The patient demonstrated generalized hypotonia, pyramidal tract dysfunction and temperature instability after the second month of life. Dystonia, tremor and oculogyric crises complicated the clinical picture during the following months. Neurotransmitter analysis in CSF disclosed almost undetectable levels of HVA and MHPG, whereas serum prolactin was profoundly increased. Subsequent molecular analysis revealed homozygosity for a missense mutation (c.707T>C) in the TH gene. l-Dopa therapy in both high and low doses resulted in massive hyperkinesias, while substitution with selegiline exerted only a mild beneficial effect. Today, at the age of 7 years, the patient demonstrates severe developmental retardation with marked trunkal hypotonia, hypokinesia and occasionally dystonic and/or hyperkinetic crises. He is the third Greek patient with TH deficiency to be reported. Since all three patients carry the same pathogenetic mutation, a founder effect is suspected.

A worldwide multicentre comparison of assays for cerebrospinal fluid biomarkers in Alzheimer's disease.

BACKGROUND: Different cerebrospinal fluid (CSF) amyloid-beta 1-42 (Abeta(1-42)), total Tau (Tau) and Tau phosphorylated at threonine 181 (P-Tau) levels are reported, but currently there is a lack of quality control programmes. The aim of this study was to compare the measurements of these CSF biomarkers, between and within centres. METHODS: Three CSF-pool samples were distributed to 13 laboratories in 2004 and the same samples were again distributed to 18 laboratories in 2008. In 2004 six laboratories measured Abeta(1-42), Tau and P-Tau and seven laboratories measured one or two of these marker(s) by enzyme-linked immunosorbent assays (ELISAs). In 2008, 12 laboratories measured all three markers, three laboratories measured one or two marker(s) by ELISAs and three laboratories measured the markers by Luminex. RESULTS: In 2004, the ELISA intercentre coefficients of variance (interCV) were 31%, 21% and 13% for Abeta(1-42), Tau and P-Tau, respectively. These were 37%, 16% and 15%, respectively, in 2008. When we restricted the analysis to the Innotest (N = 13) for Abeta(1-42), lower interCV were calculated (22%). The centres that participated in both years (N = 9) showed interCVs of 21%, 15% and 9% and intra-centre coefficients (intraCV) of variance of 25%,18% and 7% in 2008. CONCLUSIONS: The highest variability was found for Abeta(1-42). The variabilities for Tau and P-Tau were lower in both years. The centres that participated in both years showed a high intraCV comparable to their interCV, indicating that there is not only a high variation between but also within centres. Besides a uniform standardization of (pre)analytical procedures, the same assay should be used to decrease the inter/intracentre variation.

Biomarkers in spinal cord injury.

STUDY DESIGN: Literature review. OBJECTIVES: In traumatic spinal cord injury (SCI), much effort has been put into the evaluation of SCI severity and the prediction of recovery potential. An accurate prediction of the initial damage of the spinal cord that differentiates between the severities of SCI however, may help physicians in choosing a particular neuroprotective treatment in the acute phase. Neurochemical biomarkers may possibly fulfil these requirements. The aim of this review was to describe (1) the current status of neurochemical biomarkers in SCI; (2) their potential diagnostic role in SCI. METHODS: MEDLINE was searched from 1966 to 2008 to identify publications concerning biomarkers in traumatic SCI. RESULTS: The biomarkers S-100beta, neuron-specific enolase, neurofilament light chain, and Glial fibrillary acidic protein are significantly increased in cases of (experimental) spinal cord injury. Furthermore, increased serum concentrations of S-100beta have been correlated with an unfavourable functional outcome. Although biomarkers in SCI show promising results, considerations and shortcomings, such as polytrauma, haemolysis, extracerebral sources, and poor resuscitation, must be studied in greater detail before biomarkers can be utilised in the clinical care of SCI. CONCLUSIONS: Quantitative standards for determining the extent of SCI during the acute phase must be developed and validated. Even though increased concentrations of neurochemical biomarkers have been identified in patients with SCI, these do not yet provide a sensitive prognostic tool. Considering the limited availability of sensitive prognostic tools, neurochemical biomarkers of SCI should be evaluated and validated in future clinical trials.

Technical and biochemical factors affecting cerebrospinal fluid 5-MTHF, biopterin and neopterin concentrations.

BACKGROUND: The diagnosis of pediatric neurologic disorders with a deficiency in the biosynthesis of either the neurotransmitters serotonin and dopamine, or the co-factor tetrahydrobiopterin or a cerebral 5-methyltetrahydrofolate (5-MTHF) deficiency, strongly relies on a robust analysis of neurotransmitter metabolites, pterins and 5-MTHF in the cerebrospinal fluid (CSF). The aim of this study was to investigate which technical and biochemical factors affect the CSF concentration of 5-MTHF, neopterin and biopterin in a pediatric population. METHODS: We studied effects of the ventriculo-spinal gradient, total protein concentration, pretreatment with ascorbic acid (in case of 5-MTHF analysis), pretreatment of CSF with trichloro acetic acid (TCA)/dithiotreitol (DTE) and oxidation with either iodine or manganese oxide (in case of pterin analysis), storage time and age of the patients. We included CSF samples from children until the age of 18 years and analysed 5-MTHF, neopterin, biopterin, homovanillic acid (HVA), 5-hydroxy-indoleacetic acid (5-HIAA) and total protein. RESULTS: The major findings of our study are: (1) CSF 5-MTHF, neopterin and biopterin concentrations are not affected by the ventriculo-spinal gradient; (2) pretreatment of CSF with ascorbic acid has negligible effects on 5-MTHF concentrations; (3) pretreatment of CSF with TCA/DTE and oxidation with iodine results in the most accurate determination of neopterin and biopterin; (4) when adjusted for age and total protein, CSF 5-MTHF correlated with 5-HIAA, but not with HVA; (5) the reference value of 5-MTHF in CSF in childhood is age-dependent (r=-0.634; p0.001); (6) we did not observe an age-dependency for neopterin and biopterin in CSF. CONCLUSION: 5-MTHF, neopterin and biopterin can be analysed in any volume of CSF that is collected. For correct analysis of pterins, CSF will have to be pretreated to stabilize the concentrations and stored properly, whereas such pretreatment is not necessary for 5-MTHF.

CSF hypocretin-1 levels are normal in multiple-system atrophy.

Sleep disturbances occur in 70% of the patients with multiple system atrophy (MSA). Disturbances of the hypothalamic hypocretin neurotransmission have been suggested as a possible cause. Since a systematic study of CSF hypocretin-1 levels in MSA has not yet been performed, we analysed CSF hypocretin-1 concentrations in 6 MSA-P and 6 MSA-C patients and 11 age-matched controls. We did not observe any differences from control values.

CSF neurofilament proteins in the differential diagnosis of dementia.

BACKGROUND: Neurofilament (NF) proteins are major cytoskeletal constituents of neurons. Increased CSF NF levels may reflect neuronal degeneration. OBJECTIVE: To investigate the diagnostic value of CSF NF analysis to discriminate in relatively young dementia patients between frontotemporal lobe degeneration (FTLD) and early onset Alzheimer's disease (EAD; onset < or = 65 years of age), and in elderly dementia patients between dementia with Lewy bodies (DLB) and late onset AD (LAD; onset > 65 years of age). METHODS: In CSF of 28 FTLD, 37 EAD, 18 DLB and 33 LAD patients, and 26 control subjects, we analysed NF light chain (NFL), phosphorylated NF heavy chain (pNFH), amyloid beta42 protein (Abeta42), total tau and tau phosphorylated at threonine 181 (p-tau181). RESULTS: CSF NFL levels were higher in FTLD patients compared with EAD patients (p<0.001), and diagnostic accuracy of p-tau181 and Abeta42 analysis improved with addition of NFL analysis (sensitivity 86%, specificity 100%). CSF pNFH levels were elevated in DLB, LAD and FTLD compared with controls (p<0.05) but no significant differences were found between the dementia groups. CONCLUSIONS: In the diagnostic workup of relatively young dementia patients, CSF NFL levels may play a role in the discrimination between FTLD and EAD, especially in combination with Abeta42 and p-tau181 analysis.

Diagnostic accuracy of the clapping test in Parkinsonian disorders.

BACKGROUND: To determine the diagnostic value of the clapping test, which has been proposed as a reliable measure to differentiate between progressive supranuclear palsy (where performance is impaired) and Parkinson's disease (where performance should be normal). METHODS: Our study group included a large cohort of consecutive outpatients including 44 patients with Parkinson's disease, 48 patients with various forms of atypical parkinsonism and 149 control subjects. All subjects performed the clapping test according to a standardized protocol. RESULTS: Clapping test performance was normal in all control subjects, and impaired in 63% of the patients with atypical parkinsonism. Unexpectedly, we also found an impaired clapping test in 29% of the patients with Parkinson's disease. CONCLUSION: Although the proportion with an abnormal clapping test was significantly higher in atypical parkinsonism, the clapping test did not discriminate well between Parkinson's disease and atypical parkinsonism.