Baseline Cerebrospinal Fluid Research Articles

CSF tau and tau/Aβ42 predict cognitive decline in Parkinson's disease.

A substantial proportion of patients with Parkinson's disease (PD) have concomitant cognitive dysfunction. Identification of biomarker profiles that predict which PD patients have a greater likelihood for progression of cognitive symptoms is pressingly needed for future treatment and prevention approaches. Subjects were drawn from the Deprenyl and Tocopherol Antioxidative Therapy of Parkinsonism (DATATOP) study, a large clinical trial that enrolled initially untreated PD patients. For the current study, Phase One encompassed trial baseline until just prior to levodopa administration (n = 403), and Phase Two spanned the initiation of levodopa treatment until the end of cognitive follow-up (n = 305). Correlations and linear mixed models were performed to determine cross-sectional and longitudinal associations between baseline amyloid β1-42 (Aβ42), total tau (t-tau), and phosphorylated tau (p-tau) in cerebrospinal fluid (CSF) and measures of memory and executive function. Analyses also considered APOE genotype and tremor- vs. rigidity-dominant phenotype. No association was found between baseline CSF biomarkers and cognitive test performance during Phase One. However, once levodopa treatment was initiated, higher p-tau and p-tau/Aβ42 predicted subsequent decline on cognitive tasks involving both memory and executive functions. The interactions between biomarkers and cognition decline did not appear to be influenced by levodopa dosage, APOE genotype or motor phenotype. The current study has, for the first time, demonstrated the possible involvement of tau species, whose gene (MAPT) has been consistently linked to the risk of PD by genome-wide association studies, in the progression of cognitive symptoms in PD.

Network Diffusion Model of Progression Predicts Longitudinal Patterns of Atrophy and Metabolism in Alzheimer’s Disease

Alzheimer's disease pathology (AD) originates in the hippocampus and subsequently spreads to temporal, parietal, and prefrontal association cortices in a relatively stereotyped progression. Current evidence attributes this orderly progression to transneuronal transmission of misfolded proteins along the projection pathways of affected neurons. A network diffusion model was recently proposed to mathematically predict disease topography resulting from transneuronal transmission on the brain's connectivity network. Here, we use this model to predict future patterns of regional atrophy and metabolism from baseline regional patterns of 418 subjects. The model accurately predicts end-of-study regional atrophy and metabolism starting from baseline data, with significantly higher correlation strength than given by the baseline statistics directly. The model's rate parameter encapsulates overall atrophy progression rate; group analysis revealed this rate to depend on diagnosis as well as baseline cerebrospinal fluid (CSF) biomarker levels. This work helps validate the model as a prognostic tool for Alzheimer's disease assessment.

Cytokines, MMP-2, and MMP-9 levels in patients with a solitary cysticercus granuloma.

In patients with neurocysticercosis, perilesional inflammatory activity is thought to be responsible for seizures. This study was designed to evaluate the serum and cerebrospinal fluid (CSF) concentrations of cytokines as well as matrix metalloproteinase (MMP)-2 and MMP-9 in patients with a solitary cysticercus granuloma. The study included 47 patients suffering from seizures in whom a solitary cysticercus granuloma was detected on a computed tomography (CT) scan. The study also included 47 control subjects. Their serum and cerebrospinal fluid (CSF) was analysed for cytokines and MMP levels. A follow-up CT was performed after 6 months. The median levels of cytokines, interleukin (IL)-1β, IL-5, IL-6, IL-10 and tissue necrosis factor (TNF)-α, MMP-2 and MMP-9 were significantly elevated, both in the serum and CSF of patients having an intracerebral solitary cysticercus granuloma, in comparison to that of controls. The follow-up CT revealed that in 27 patients, the lesions were calcified and in 5 patients, there was complete resolution of the lesions. In 15 patients, the lesions remained unchanged. Higher baseline CSF MMP-2 and TNF-α level were seen in patients with persisting lesions. Higher serum baseline MMP-2, IL-6 and a low CSF IL-10 level were seen in patients with complete resolution of the granuloma. A high baseline IL-1β level was associated with a calcified lesion. Fourteen patients had recurrence of seizures. A high baseline serum TNF-α level was independently associated with seizure recurrence (P = 0.021, OR = 1.041, CI = 1.006 to 1.078). In patients with a solitary cysticercus granuloma, cytokines and matrix metalloproteinases in the CSF and serum are elevated. Different patterns of immunological changes were observed in patients following resolution or calcification of the lesion.

The transitional association between β-amyloid pathology and regional brain atrophy

IntroductionAlzheimer's disease (AD) is characterized by the accumulation of β-amyloid (Aβ) associated with brain atrophy and cognitive decline. The functional form to model the association between Aβ and regional brain atrophy has not been well defined. To determine the relationship between Aβ and atrophy, we compared the performance of the usual dichotomization of cerebrospinal fluid (CSF) Aβ to identify subjects as Aβ+ and Aβ− with a trilinear spline model of CSF Aβ. MethodsOne hundred and eighty-three subjects with mild cognitive impairment and 108 cognitively normal controls with baseline CSF Aβ and up to 4 years of longitudinal magnetic resonance imaging data from the Alzheimer's Disease Neuroimaging Initiative were analyzed using mixed-effects regression. Piecewise-linear splines were used to evaluate the nonlinear nature of the association between CSF Aβ and regional atrophy and to identify points of acceleration of atrophy with respect to Aβ. Several parameterizations of CSF Aβ were compared using likelihood ratio tests and the Akaike information criterion. Periods of acceleration of atrophy in which subjects transition from CSF Aβ negativity to CSF Aβ positivity were estimated from the spline models and tested for significance. ResultsSpline models resulted in better fits for many temporal and parietal regions compared with the dichotomous models. The trilinear model showed that periods of acceleration of atrophy varied greatly by region with early changes seen in the insula, amygdala, precuneus, hippocampus, and other temporal regions, occurring before the clinical threshold for CSF Aβ positivity. DiscussionThe use of piecewise-linear splines provides an improved model of the nonlinear association between CSF Aβ and regional atrophy in regions implicated in the progression of AD. The important biological finding of this work is that some brain regions show periods of accelerated volume loss well before the CSF Aβ42 threshold. This implies that signs of brain atrophy develop before the current conventional definition of “preclinical AD”.

Cerebrospinal fluid α-synuclein and Lewy body-like symptoms in normal controls, mild cognitive impairment, and Alzheimer's disease.

Reduced cerebrospinal fluid (CSF) α-synuclein has been described in synucleinopathies, including dementia with Lewy bodies (DLB). Common symptoms of DLB include visual hallucinations and visuospatial and executive deficits. Co-occurrence of Lewy body pathology is common in Alzheimer's disease (AD) patients, but it is unknown if reduced CSF α-synuclein is associated with Lewy body-like symptomatology in AD. Determine associations between CSF α-synuclein and Lewy body-like symptomatology. We included 73 controls (NC), 121 mild cognitive impairment (MCI) patients, and 61 AD patients (median follow-up 3.5 years, range 0.6-7.8). We tested associations between baseline CSF α-synuclein and visual hallucinations and (longitudinal) cognition. Models were tested with and without co-varying for CSF total tau (T-tau), which is elevated in AD patients, and believed to reflect neurodegeneration. Hallucinations were reported in 20% of AD patients, 13% of MCI patients, and 8% of NC. In AD, low CSF α-synuclein was associated with hallucinations. When adjusting for CSF T-tau, low CSF α-synuclein was associated with accelerated decline of executive function (NC, MCI, and AD), memory (MCI and AD), and language (MCI). The associations of low CSF α-synuclein with hallucinations and poor executive function, which are hallmarks of DLB, indirectly suggest that this biomarker may reflect underlying synuclein pathology. The associations with memory and language in MCI and AD suggests either that reduced CSF α-synuclein also partly reflects global impaired neuronal/synaptic function, or that non-specific overall cognitive deterioration is accelerated in the presence of synuclein related pathology. The findings will require autopsy verification.

The mediational effects of FDG hypometabolism on the association between cerebrospinal fluid biomarkers and neurocognitive function

Positive cerebrospinal fluid (CSF) biomarkers of tau and amyloid beta42 suggest possible active underlying Alzheimer's disease (AD) including neurometabolic dysfunction and neurodegeneration leading to eventual cognitive decline. But the temporal relationship between CSF, imaging markers of neural function, and cognition has not been described. Using a statistical mediation model, we examined relationships between cerebrospinal fluid (CSF) analytes (hyperphosphorylated tau (p-Tau181p), β-amyloid peptides 1–42 (Aβ1–42), total tau (t-Tau), and their ratios); change in cognitive function; and change in [18F]fluorodeoxyglucose (FDG) uptake using positron emission tomography (PET). We hypothesized that a) abnormal CSF protein values at baseline, result in cognitive declines by decreasing neuronal glucose metabolism across time, and b) the role of altered glucose metabolism in the assumed causal chain varies by brain region and the nature of CSF protein alteration.Data from 412 individuals participating in Alzheimer's Disease Neuroimaging (ADNI) cohort studies were included in analyses. At baseline, individuals were cognitively normal (N=82), or impaired: 241 with mild cognitive impairment, and 89 with Alzheimer's disease. A parallel-process latent growth curve model was used to test mediational effects of changes in regional FDG-PET uptake over time in relation to baseline CSF biomarkers and changes in cognition, measured with the 13-item Alzheimer Disease's Assessment Scale–cognitive subscale (ADAS–Cog).Findings suggested a causal sequence of events; specifically, FDG hypometabolism acted as a mediator between antecedent CSF biomarker alterations and subsequent cognitive impairment. Higher baseline concentrations of t-Tau, and p-Tau181p were more predictive of decline in cerebral glucose metabolism than lower baseline concentrations of Aβ1–42. FDG-PET changes appeared to mediate t-Tau or t-Tau/Aβ1–42-associated cognitive change across all brain regions examined. Significant direct effects of alterations in Aβ1–42 levels on hypometabolism were observed in a single brain region: middle/inferior temporal gyrus.Results support a temporal framework model in which reduced CSF amyloid-related biomarkers occur earlier in the pathogenic pathway, ultimately leading to detrimental cognitive effects. Also consistent with this temporal framework model, baseline markers of neurofibrillary degeneration predicted changes in brain glucose metabolism in turn causing longitudinal cognitive changes, suggesting that tau-related burden precedes neurometabolic dysfunction. While intriguing, the hypothesized mediational relationships require further validation.

Apolipoprotein E genotype and the diagnostic accuracy of cerebrospinal fluid biomarkers for Alzheimer disease.

Several studies suggest that the apolipoprotein E (APOE) ε4 allele modulates cerebrospinal fluid (CSF) levels of β-amyloid 42 (Aβ42). Whether this effect is secondary to the association of the APOE ε4 allele with cortical Aβ deposition or whether APOE ε4 directly influences CSF levels of Aβ42 independently of Aβ pathology remains unknown. To evaluate whether the APOE genotype affects the diagnostic accuracy of CSF biomarkers for Alzheimer disease (AD), in particular Aβ42 levels, and whether the association of APOE ε4 with CSF biomarkers depends on cortical Aβ status. We collected data from 4 different centers in Sweden, Finland, and Germany. Cohort A consisted of 1345 individuals aged 23 to 99 years with baseline CSF samples, including 309 with AD, 287 with prodromal AD, 399 with stable mild cognitive impairment, 99 with dementias other than AD, and 251 controls. Cohort B included 105 nondemented younger individuals (aged 20-34 years) with CSF samples available. Cohort C included 118 patients aged 60 to 80 years with mild cognitive symptoms who underwent flutemetamol F 18 ([18F]flumetamol) positron emission tomography amyloid imaging and CSF tap. Standard care. Cerebrospinal fluid levels of Aβ42 and total and phosphorylated tau in relation to the APOE ε2/ε3/ε4 polymorphism in different diagnostic groups and in cases with or without cortical uptake of [18F]flutemetamol. The CSF levels of Aβ42 but not total and phosphorylated tau were lower in APOE ε4 carriers compared with noncarriers irrespective of diagnostic group (cohort A). Despite this, CSF levels of Aβ42 differed between participants with AD when compared with controls and those with stable mild cognitive impairment, even when stratifying for APOE genotype (P < .001 to P = .006). Multiple binary logistic regression revealed that CSF levels of Aβ42 and APOE ε4 genotype were independent predictors of AD diagnosis. In cohort B, APOE ε4 carrier status did not influence CSF levels of Aβ42. Moreover, when stratifying for cortical uptake of [18F]flutemetamol in cohort C, APOE ε4 genotype did not influence CSF levels of Aβ42. This result was replicated in a cohort with individuals from the Alzheimer's Disease Neuroimaging Initiative (ADNI) using carbon 11-labeled Pittsburgh Compound B scanning. Cerebrospinal fluid levels of Aβ42 are strongly associated with the diagnosis of AD and cortical Aβ accumulation independent of APOE genotype. The clinical cutoff for CSF levels of Aβ42 should be the same for all APOE genotypes.

Plasma and cerebrospinal fluid amyloid beta for the diagnosis of Alzheimer's disease dementia and other dementias in people with mild cognitive impairment (MCI).

Plasma and cerebrospinal fluid amyloid beta for the diagnosis of Alzheimer's disease dementia and other dementias in people with mild cognitive impairment (MCI).

Cross-sectional and longitudinal relationships between cerebrospinal fluid biomarkers and cognitive function in people without cognitive impairment from across the adult life span.

Age-related cognitive decline among older individuals with normal cognition is a complex trait that potentially derives from processes of aging, inherited vulnerabilities, environmental factors, and common latent diseases that can progress to cause dementia, such as Alzheimer disease and vascular brain injury. To use cerebrospinal fluid (CSF) biomarkers to gain insight into this complex trait. Secondary analyses of an academic multicenter cross-sectional (n = 315) and longitudinal (n = 158) study of 5 neuropsychological tests (Immediate Recall, Delayed Recall, Trail Making Test Parts A and B, and Category Fluency) in cognitively normal individuals aged 21 to 100 years. To investigate the association of these cognitive function test results with age, sex, educational level, inheritance of the ε4 allele of the apolipoprotein E gene, and CSF concentrations of β-amyloid 42 (Aβ42) and tau (biomarkers of Alzheimer disease) as well as F2-isoprostanes (measures of free radical injury). Age and educational level were broadly predictive of cross-sectional cognitive performance; of the genetic and CSF measures, only greater CSF F2-isoprostane concentration was significantly associated with poorer executive function (adjusted R2 ≤0.31). Longitudinal measures of cognitive abilities, except Category Fluency, also were associated broadly with age; of the genetic and CSF measures, only lower baseline CSF Aβ42 concentration was associated with longitudinal measures of immediate and delayed recall (marginal R2 ≤0.31). Our results suggest that age and educational level accounted for a substantial minority of variance in cross-sectional or longitudinal cognitive test performance in this large group of cognitively normal adults. Latent Alzheimer disease and other diseases that produce free radical injury, such as vascular brain injury, accounted for a small amount of variation in cognitive test performance across the adult human life span. Additional genetic and environmental factors likely contribute substantially to age-related cognitive decline.

Disease progression model for Clinical Dementia Rating-Sum of Boxes in mild cognitive impairment and Alzheimer's subjects from the Alzheimer's Disease Neuroimaging Initiative.

BackgroundThe objective of this analysis was to develop a nonlinear disease progression model, using an expanded set of covariates that captures the longitudinal Clinical Dementia Rating Scale–Sum of Boxes (CDR–SB) scores. These were derived from the Alzheimer’s Disease Neuroimaging Initiative ADNI-1 study, of 301 Alzheimer’s disease and mild cognitive impairment patients who were followed for 2–3 years.MethodsThe model describes progression rate and baseline disease score as a function of covariates. The covariates that were tested fell into five groups: a) hippocampal volume; b) serum and cerebrospinal fluid (CSF) biomarkers; c) demographics and apolipoprotein Epsilon 4 (ApoE4) allele status; d) baseline cognitive tests; and e) disease state and comedications.ResultsCovariates associated with baseline disease severity were disease state, hippocampal volume, and comedication use. Disease progression rate was influenced by baseline CSF biomarkers, Trail-Making Test part A score, delayed logical memory test score, and current level of impairment as measured by CDR–SB. The rate of disease progression was dependent on disease severity, with intermediate scores around the inflection point score of 10 exhibiting high disease progression rate. The CDR–SB disease progression rate in a typical patient, with late mild cognitive impairment and mild Alzheimer’s disease, was estimated to be approximately 0.5 and 1.4 points/year, respectively.ConclusionsIn conclusion, this model describes disease progression in terms of CDR–SB changes in patients and its dependency on novel covariates. The CSF biomarkers included in the model discriminate mild cognitive impairment subjects as progressors and nonprogressors. Therefore, the model may be utilized for optimizing study designs, through patient population enrichment and clinical trial simulations.

Biomarkers for Predicting Cognitive Decline in those with Normal Cognition

Most studies evaluating Alzheimer's disease (AD) biomarkers longitudinally have studied patients with mild cognitive impairment (MCI) who progress to AD; data on normal subjects are scarce. We studied which biomarkers best predict cognitive decline on the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog) among those with normal cognition at baseline, and derived cut points to predict decline. We studied 191 subjects in the Alzheimer's Disease Neuroimaging Initiative (ADNI) who had normal cognition at baseline, 2 + visits (mean follow-up 3.1 years), and data on neuropsychological tests, cerebrospinal fluid (CSF) biomarkers, and structural MRI. We used repeated measures linear regression of log ADAS-Cog on age, race, gender, education, APOE4 status, baseline biomarker values, and follow-up time; an interaction between biomarker and time assessed predictive power. Neuropsychological tests did not significantly predict ADAS-Cog decline, while both MRI variables and CSF biomarkers did; CSF markers were the strongest predictors. Optimal cut points for baseline CSF markers to distinguish decliners were < 220 pg/ml (Aβ42), ≥61 pg/ml (t-tau), ≥21 pg/ml (p-tau), ≥0.31 (t-tau/Aβ42), and ≥0.10 (p-tau/Aβ42). For progression to MCI/AD (n = 28), the best markers were t-tau, t-tau/Aβ42, and p-tau/Aβ42, with optimal cut points of 58, 0.31, and 0.08, respectively. The optimal cut points across all markers and cut points predicted decline in ADAS-Cog, as well as transition to MCI, with a 65% accuracy. Our findings support current models of AD progression and suggest it is feasible to establish biomarker criteria to predict cognitive decline in individuals with normal cognition. Larger studies will be needed to more accurately characterize optimal cut points.

Biological heterogeneity in ADNI amnestic mild cognitive impairment

BackgroundPrevious work examining normal controls from the Alzheimer's Disease Neuroimaging Initiative (ADNI) identified substantial biological heterogeneity. We hypothesized that ADNI mild cognitive impairment (MCI) subjects would also exhibit heterogeneity with possible clinical implications. MethodsADNI subjects diagnosed with amnestic MCI (n = 138) were clustered based on baseline magnetic resonance imaging, cerebrospinal fluid, and serum biomarkers. The clusters were compared with respect to longitudinal atrophy, cognitive trajectory, and time to conversion. ResultsFour clusters emerged with distinct biomarker patterns: The first cluster was biologically similar to normal controls and rarely converted to Alzheimer's disease (AD) during follow-up. The second cluster had characteristics of early Alzheimer's pathology. The third cluster showed the most severe atrophy but barely abnormal tau levels and a substantial proportion converted to clinical AD. The fourth cluster appeared to be pre-AD and nearly all converted to AD. ConclusionsSubjects with MCI who were clinically similar showed substantial heterogeneity in biomarkers.

CSF Apo-E levels associate with cognitive decline and MRI changes

Apolipoprotein E (APOE) ε4 allele is the most important genetic risk factor for Alzheimer's disease (AD) and it is thought to do so by modulating levels of its product, apolipoprotein E (Apo-E), and regulating amyloid-β (Aβ) clearance. However, information on clinical and biomarker correlates of Apo-E proteins is scarce. We examined the relationship of cerebrospinal fluid (CSF) and plasma Apo-E protein levels, and APOE genotype to cognition and AD biomarker changes in 311 AD neuroimaging initiative subjects with CSF Apo-E measurements and 565 subjects with plasma Apo-E measurements. At baseline, higher CSF Apo-E levels were associated with higher total and phosphorylated CSF tau levels. CSF Apo-E levels were associated with longitudinal cognitive decline, MCI conversion to dementia, and gray matter atrophy rate in total tau/Aβ1-42 ratio and APOE genotype-adjusted analyses. In analyses stratified by APOE genotype, our results were only significant in the group without the ε4 allele. Baseline CSF Apo-E levels did not predict longitudinal CSF Aβ or tau changes. Plasma Apo-E levels show a mild correlation with CSF Apo-E levels, but were not associated with longitudinal cognitive and MRI changes. Based on our analyses, we speculate that increased CSF Apo-E2 or -E3 levels might represent a protective response to injury in AD and may have neuroprotective effects by decreasing neuronal damage independent of tau and amyloid deposition in addition to its effects on amyloid clearance.

Preterm lambs given intravenous dopamine show increased dopamine in their cerebrospinal fluid

Dopamine is used as an inotropic medication in preterm infants. The preterm human blood brain barrier (BBB) is permeable to intravascular dopamine, and the impact of exogenous dopamine on the preterm brain remains unknown. The preterm lamb model may be suitable for studying the cerebral impact of dopamine therapy whether its BBB permeability is similar to preterm human infants. We aimed to examine BBB permeability to exogenous dopamine in the preterm lamb, by measuring dopamine levels in the cerebrospinal fluid (CSF). Nine preterm foetal lambs (125-130 days, term = 147 days) were given either dopamine at 10 μg/kg/min (dopamine, n = 4) or saline (control, n = 5). CSF, and plasma samples were taken for dopamine assay. The median (range) baseline CSF dopamine level for the combined control and dopamine groups (n = 9) was 0.10(0.03-0.16) ng/mL, and baseline plasma dopamine was 0.30(0.13-0.84) ng/mL. The dopamine lambs showed increase in CSF dopamine to 3.91(1.87-11.35) ng/mL with plasma dopamine increased to 14.2 (9.1-57.9) ng/mL. No change was found in the control lambs. In the preterm lamb, the BBB permeability and pharmacokinetics to dopamine infusion are similar to findings in the preterm human infant, supporting applicability of the preterm lamb model for studying effects of dopamine infusion in the preterm human brain.

Effects of Baseline CSF α-Synuclein on Regional Brain Atrophy Rates in Healthy Elders, Mild Cognitive Impairment and Alzheimer’s Disease

BackgroundCerebrospinal fluid (CSF) α-synuclein is reduced in synucleinopathies, including dementia with Lewy bodies, and some studies have found increased CSF α-synuclein in Alzheimer’s disease (AD). No study has explored effects of CSF α-synuclein on brain atrophy. Here we tested if baseline CSF α-synuclein affects brain atrophy rates and if these effects vary across brain regions, and across the cognitive spectrum from healthy elders (NL), to patients with mild cognitive impairment (MCI) and AD.MethodsBaseline CSF α-synuclein measurements and longitudinal structural brain magnetic resonance imaging was performed in 74 NL, 118 MCI patients and 55 AD patients. Effects of baseline CSF α-synuclein on regional atrophy rates were tested in 1) four pre-hoc defined regions possibly associated with Lewy body and/or AD pathology (amygdala, caudate, hippocampus, brainstem), and 2) all available regions of interest. Differences across diagnoses were tested by assessing the interaction of CSF α-synuclein and diagnosis (testing NL versus MCI, and NL versus AD).ResultsThe effects of CSF α-synuclein on longitudinal atrophy rates were not significant after correction for multiple comparisons. There were tendencies for effects in AD in caudate (higher atrophy rates in subjects with higher CSF α-synuclein, P=0.046) and brainstem (higher atrophy rates in subjects with lower CSF α-synuclein, P=0.063). CSF α-synuclein had significantly different effects on atrophy rates in NL and AD in brainstem (P=0.037) and caudate (P=0.006). Discussion: With the possible exception of caudate and brainstem, the overall weak effects of CSF α-synuclein on atrophy rates in NL, MCI and AD argues against CSF α-synuclein as a biomarker related to longitudinal brain atrophy in these diagnostic groups. Any effects of CSF α-synuclein may be attenuated by possible simultaneous occurrence of AD-related neuronal injury and concomitant Lewy body pathology, which may elevate and reduce CSF α-synuclein levels, respectively.

Changes in vitamin C and oxidative stress status during the treatment of tuberculous meningitis

Tuberculosis (TB) is associated with oxidative stress and is traditionally linked to vitamin C deficiency. To evaluate the time course of the oxidative stress marker, malondialdehyde (MDA), and vitamin C status during the clinical treatment of tuberculous meningitis (TBM). MDA and vitamin C reduction/oxidation (redox) status were spectrophotometrically measured at admission and during hospital treatment in cerebrospinal fluid (CSF) and serum from 27 TBM patients and 20 controls. Baseline CSF and serum MDA levels in TBM patients were higher than in controls (both P < 0.05), and remained elevated throughout the study. CSF MDA steadily increased from baseline 0.66 ± 0.24 mol/l to 1.02 ± 0.33 μmol/l at the end of the sixth week of treatment (P < 0.05), and then returned to baseline levels. Baseline CSF and serum total vitamin C were lower in TBM patients than in controls, but were soon normalised. CSF and serum ascorbate, reduced/oxidised vitamin C ratios and ascorbate CSF/serum ratio were markedly decreased in TBM patients (P < 0.05), and showed no improvement during treatment. These results indicate increased local and systemic oxidative stress, accompanied by impaired redox status, but not total vitamin C deficiency, which persisted during conventional clinical treatment of TBM.

Effects of cerebrospinal fluid proteins on brain atrophy rates in cognitively healthy older adults

Biomarkers associated with Alzheimer's disease (AD)–like brain atrophy in healthy individuals may identify mechanisms involved in early stage AD. Aside from cerebrospinal fluid (CSF) β-amyloid42 (Aβ42) and tau, no studies have tested associations between CSF proteins and AD-like brain atrophy. We studied 90 healthy elders, who underwent lumbar puncture at baseline, and serial magnetic resonance imaging scans for up to 4 years. We tested statistical effects of baseline CSF proteins (N = 70 proteins related to Aβ42-metabolism, microglial activity, and synaptic/neuronal function) on atrophy rates in 7 AD-related regions. Besides the effects of Aβ42 and phosphorylated tau (P-tau) that were seen in several regions, novel CSF proteins were found to have effects in inferior and middle temporal cortex (including apolipoprotein CIII, apolipoprotein D, and apolipoprotein H). Several proteins (including S100β and matrix metalloproteinase–3) had effects that depended on the presence of brain Aβ pathology, as measured by CSF Aβ42. Other proteins (including P-tau and apolipoprotein D) had effects even after adjusting for CSF Aβ42. The statistical effects in this exploratory study were mild and not significant after correction for multiple comparisons, but some of the identified proteins may be associated with brain atrophy in healthy persons. Proteins interacting with CSF Aβ42 may be related to Aβ brain pathology, whereas proteins associated with atrophy even after adjusting for CSF Aβ42 may be related to Aβ-independent mechanisms.

Determination of Immune Surveillance in Cerebrospinal Fluid (CSF) in Patients with Crohnʼs Disease: Initial Results of the TOSCA Study

Purpose: The risk of progressive multifocal leukoencephalopathy (PML) is increased by natalizumab, a therapeutic antibody used for multiple sclerosis and crohn's disease (CD) that blocks both α4β1 and α4β7 integrins, and thereby inhibits both central nervous system (CNS) and gut trafficking of lymphocytes. Natalizumab therapy is associated with marked reduction in CSF total and CD4+ lymphocytes, and an inverted CD4:CD8 ratio, which indicates deficient CNS immune surveillance, the putative mechanism contributing to PML caused by JC virus infection/reactivation. The investigational drug PF-00547659 (PF) is a fully human anti-MAdCAM monoclonal antibody designed to reduce lymphocyte homing exclusively to the gut, for the treatment of inflammatory bowel disease (IBD). Because of the low incidence of natalizumab associated PML, comparing risk between these drugs in clinical trials is difficult. However, 6 weeks after one injection of natalizumab, a dramatic drop in CSF lymphocytes and CD4 cells occurs. Thus, an additional approach to assess drug-induced PML risk may be to determine the effect of a new agent on CNS T lymphocytes. The purpose of this study is to assess whether PF alters trafficking of the lymphocyte population to the CNS, reflecting immune surveillance in CD patients. Methods: TOSCA is an open-label study of PF designed in two cohorts. Cohort 1 explored baseline CSF values at two different lumbar puncture (LP) visits before administration of PF, whereas cohort 2 is designed to investigate CSF composition before and during treatment with PF. We present here the data from Cohort 1, along with concurrent data from five healthy subjects. CSF from adults with moderately-to-severely active CD, who failed prior treatment with immunosuppressants (IS) and anti-TNF, was analyzed by FACS. Results: Of 10 CD pts, eight were men, age (mean±sd) was 40.8±16.0 years, CD duration was 13.5±6.1 years, and HBI was 8.6±2.8 for seven patients (three had stomas). Data from two patients were discarded because of inaccurate cell counting. Three patients did not have a 2nd LP because of headache. FACS data, in cells/mL, are shown in the table.Table: Table. Geometric mean values (CV%)Conclusion: CSF lymphocyte counts are similar between healthy subjects and patients with moderate-to-severe CD. Repeat testing showed stable CSF lymphocyte populations, indicating lack of inflammatory changes after LP. This approach offers promise in assessing risk of anti-integrin therapy. Disclosure - Fabio Cataldi Employee, of Pfizer inc. Kenneth Gorelick Employee of Pfizer inc Sunday Rivers Employee of Pfizer inc Mina Hassan-Zahraee Employee of Pfizer inc John Cheng Employee of Pfizer inc Bo Jin Employee of Pfizer inc Jenny Yanhua.Zhang Employee of Pfizer inc William Sandborn Consultant Pfizer Walter Reinisch Consultant Pfizer Geert D'Haens Consultant Pfizer Andre Van Gossum None Richard Ransohoff None Olaf Stuve None. This research was supported by an industry grant from Pfizer Inc.

Cryptococcus neoformans ex vivo capsule size is associated with intracranial pressure and host immune response in HIV-associated cryptococcal meningitis.

Background. The Cryptococcus neoformans polysaccharide capsule is a well-characterized virulence factor with immunomodulatory properties. The organism and/or shed capsule is postulated to raise intracranial pressure (ICP) in cryptococcal meningitis (CM) by mechanical obstruction of cerebrospinal fluid (CSF) outflow. Little is known regarding capsule phenotype in human cryptococcosis. We investigated the relationship of ex vivo CSF capsular phenotype with ICP and CSF immune response, as well as in vitro phenotype.Methods. In total, 134 human immunodeficiency virus (HIV)-infected Ugandan adults with CM had serial lumbar punctures with measurement of CSF opening pressures, quantitative cultures, ex vivo capsule size and shedding, viscosity, and CSF cytokines; 108 had complete data. Induced capsular size and shedding were measured in vitro for 48 C. neoformans isolates.Results. Cryptococcal strains producing larger ex vivo capsules in the baseline (pretreatment) CSF correlated with higher ICP (P = .02), slower rate of fungal clearance (P = .02), and paucity of CSF inflammation, including decreased CSF white blood cell (WBC) count (P < .001), interleukin (IL)-4 (P = .02), IL-6 (P = .01), IL-7 (P = .04), IL-8 (P = .03), and interferon γ (P = .03). CSF capsule shedding did not correlate with ICP. On multivariable analysis, capsule size remained independently associated with ICP. Ex vivo capsular size and shedding did not correlate with that of the same isolates grown in vitro.Conclusions. Cryptococcal capsule size ex vivo is an important contributor to virulence in human cryptococcal meningitis.

CSF protein biomarkers predicting longitudinal reduction of CSF β-amyloid42 in cognitively healthy elders

β-amyloid (Aβ) plaque accumulation is a hallmark of Alzheimer's disease (AD). It is believed to start many years prior to symptoms and is reflected by reduced cerebrospinal fluid (CSF) levels of the peptide Aβ1–42 (Aβ42). Here we tested the hypothesis that baseline levels of CSF proteins involved in microglia activity, synaptic function and Aβ metabolism predict the development of Aβ plaques, assessed by longitudinal CSF Aβ42 decrease in cognitively healthy people. Forty-six healthy people with three to four serial CSF samples were included (mean follow-up 3 years, range 2–4 years). There was an overall reduction in Aβ42 from a mean concentration of 211–195 pg ml−1 after 4 years. Linear mixed-effects models using longitudinal Aβ42 as the response variable, and baseline proteins as explanatory variables (n=69 proteins potentially relevant for Aβ metabolism, microglia or synaptic/neuronal function), identified 10 proteins with significant effects on longitudinal Aβ42. The most significant proteins were angiotensin-converting enzyme (ACE, P=0.009), Chromogranin A (CgA, P=0.009) and Axl receptor tyrosine kinase (AXL, P=0.009). Receiver-operating characteristic analysis identified 11 proteins with significant effects on longitudinal Aβ42 (largely overlapping with the proteins identified by linear mixed-effects models). Several proteins (including ACE, CgA and AXL) were associated with Aβ42 reduction only in subjects with normal baseline Aβ42, and not in subjects with reduced baseline Aβ42. We conclude that baseline CSF proteins related to Aβ metabolism, microglia activity or synapses predict longitudinal Aβ42 reduction in cognitively healthy elders. The finding that some proteins only predict Aβ42 reduction in subjects with normal baseline Aβ42 suggest that they predict future development of the brain Aβ pathology at the earliest stages of AD, prior to widespread development of Aβ plaques.