Tau protein level in cerebrospinal fluid is increased in patients with early multiple sclerosis

Axonal damage has been proposed as the major substrate of permanent clinical disability in multiple sclerosis. Tau protein, a microtubule-associated protein localised in neuronal axons, may serve as a biochemical surrogate marker to evaluate axonal damage in vivo.We intended to determine the extent of axonal damage in different stages and clinical subtypes of MS by investigating cerebrospinal fluid tau concentrations. Tau was measured using an immunoassay in 35 patients with relapsing—remitting MS, eight patients with secondary progressive MS, nine patients with primary progressive MS, 50 patients with clinically isolated syndrome suggestive of early MS and 46 normal controls. Cerebrospinal fluid tau was significantly elevated in MS compared with normal controls (median 206.0 pg/mL versus152.0 pg/mL;P=0.002). No significant difference among different subtypes of MS could be detected, although highest levels were found in very early disease stages. There was a significant elevation of CSF tau among patients with gadolinium-enhancing brain lesions in magnetic resonance imaging (P=0.02) and a tendency towards higher CSF tau levels in patients with pronounced intrathecal IgG synthesis, supporting the notion that axonal damage is influenced by inflammatory activity.

Fat-free mass and its predictors in Huntington's disease

The causes of weight loss in Huntington's disease (HD) are not entirely clear. The aim was to identify risk factors that are associated with a loss of metabolically active tissues, i.e. fat-free mass. A consecutive cohort of non-diabetic HD participants (manifest HD, n = 43; CAG: mean 43.6.0 ± 3.6; preHD, n = 10; CAG: mean 41.4 ± 1.4) and 36 healthy controls was recruited. Twenty-five HD participants were early-stage HD (UHDRS Total Functional Capacity [TFC] stages I and II), 12 mid-stage HD (TFC stage III), and 6 participants were in late-stage HD (TFC stages IV and V). Food intake, basic metabolic rate and glucose homeostasis were assessed. In addition, fat-free mass was determined using bioelectric impedance analysis, and leptin, insulin and ghrelin as key metabolic regulators. Sex ratio and age were similar in HD participants (71 % women; age 50.6 ± 10.9) and controls (66 % women; age 46.4 ± 14.5). Body mass index (BMI) was lower in HD participants than controls (median 24.1 vs. 25.9, p = 0.04). However, fat-free mass and basic metabolic rate were not statistically different between groups and showed no association with disease burden. In controls and HD participants, leptin was the most important predictor of fat-free mass. While BMI was lower in HD participants, fat-free mass was similar to controls with leptin as its most important predictor. Leptin levels and fat-free mass measurements using bioelectric impedance analysis may be good screening tools to identify HD patients at risk for weight loss.

Abnormal resting-state connectivity of motor and cognitive networks in early manifest Huntington's disease

BACKGROUND

Functional magnetic resonance imaging (fMRI) of multiple neural networks during the brain's 'resting state' could facilitate biomarker development in patients with Huntington's disease (HD) and may provide new insights into the relationship between neural dysfunction and clinical symptoms. To date, however, very few studies have examined the functional integrity of multiple resting state networks (RSNs) in manifest HD, and even less is known about whether concomitant brain atrophy affects neural activity in patients.

METHOD

Using MRI, we investigated brain structure and RSN function in patients with early HD (n = 20) and healthy controls (n = 20). For resting-state fMRI data a group-independent component analysis identified spatiotemporally distinct patterns of motor and prefrontal RSNs of interest. We used voxel-based morphometry to assess regional brain atrophy, and 'biological parametric mapping' analyses to investigate the impact of atrophy on neural activity.

RESULTS

Compared with controls, patients showed connectivity changes within distinct neural systems including lateral prefrontal, supplementary motor, thalamic, cingulate, temporal and parietal regions. In patients, supplementary motor area and cingulate cortex connectivity indices were associated with measures of motor function, whereas lateral prefrontal connectivity was associated with cognition.

CONCLUSIONS

This study provides evidence for aberrant connectivity of RSNs associated with motor function and cognition in early manifest HD when controlling for brain atrophy. This suggests clinically relevant changes of RSN activity in the presence of HD-associated cortical and subcortical structural abnormalities.

The neuroanatomy of subthreshold depressive symptoms in Huntington's disease: a combined diffusion tensor imaging (DTI) and voxel-based morphometry (VBM) study

BACKGROUND

Depressive symptoms are prominent psychopathological features of Huntington's disease (HD), making a negative impact on social functioning and well-being.

METHOD

We compared the frequencies of a history of depression, previous suicide attempts and current subthreshold depression between 61 early-stage HD participants and 40 matched controls. The HD group was then split based on the overall HD group's median Hospital Anxiety and Depression Scale-depression score into a group of 30 non-depressed participants (mean 0.8, s.d. = 0.7) and a group of 31 participants with subthreshold depressive symptoms (mean 7.3, s.d. = 3.5) to explore the neuroanatomy underlying subthreshold depressive symptoms in HD using voxel-based morphometry (VBM) and diffusion tensor imaging (DTI).

RESULTS

Frequencies of history of depression, previous suicide attempts or current subthreshold depressive symptoms were higher in HD than in controls. The severity of current depressive symptoms was also higher in HD, but not associated with the severity of HD motor signs or disease burden. Compared with the non-depressed HD group DTI revealed lower fractional anisotropy (FA) values in the frontal cortex, anterior cingulate cortex, insula and cerebellum of the HD group with subthreshold depressive symptoms. In contrast, VBM measures were similar in both HD groups. A history of depression, the severity of HD motor signs or disease burden did not correlate with FA values of these regions.

CONCLUSIONS

Current subthreshold depressive symptoms in early HD are associated with microstructural changes - without concomitant brain volume loss - in brain regions known to be involved in major depressive disorder, but not those typically associated with HD pathology.

CSF glial markers correlate with survival in amyotrophic lateral sclerosis

BACKGROUND

In neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), CSF biomarkers are increasingly studied to evaluate their relevance for differential diagnosis, disease progression, and understanding of pathophysiologic processes.

OBJECTIVE

To identify a biomarker profile of neuronal and glial CSF proteins to discriminate ALS from other motor neuron diseases (MND) and to assess whether baseline levels of CSF measures in ALS are associated with the course of the disease.

METHODS

A total of 122 consecutive subjects with MND were included in this cross-sectional study (ALS, n = 75; lower motor neuron syndrome, n = 39; upper motor neuron diseases, n = 8). Clinical follow-up included 76 patients. We determined baseline levels of protein tau and astroglial S100beta in CSF and microglial sCD14 in CSF and serum in relation to diagnosis, duration of disease, and survival.

RESULTS

CSF tau was significantly elevated in ALS and upper motor neuron diseases as compared to lower motor neuron diseases and controls. CSF S100beta levels were significantly lower in lower motor neuron diseases as compared to other MND. CSF concentrations of S100beta and sCD14 correlated with the survival time in patients with ALS.

CONCLUSIONS

In motor neuron diseases, CSF tau elevation indicates the degeneration of upper motor neurons, while S100 beta and sCD14 may indicate the activation of CNS glial cells. Because S100beta and sCD14 concentrations correlate with survival in amyotrophic lateral sclerosis (ALS), we suppose that the combination of both markers may be useful to obtain prognostic information in patients with ALS.

Cerebrospinal fluid proteome profile in multiple sclerosis

Cerebrospinal fluid (CSF) proteins may provide important information about the pathomechanisms present in multiple sclerosis (MS). Although diagnostic criteria for early MS are available, there is still a need for biomarkers, predicting disease subtype and progression to improve individually tailored treatment. Using the two-dimensional difference gel electrophoresis (2-D-DIGE) technology for comparative analysis, we compared CSF samples from patients with MS of the relapse-remitting type (RRMS, n = 12) and from patients with clinically isolated syndrome (CIS, n = 12) suggestive of a first demyelinating attack with neurologically normal controls. Protein spots that showed more than two-fold difference between patients and controls were selected for further analysis with MALDI-TOF mass spectrometry. Immunoblot analysis was performed to confirm the validity of individual candidate proteins. In RRMS, we identified 1 up-regulated and 10 down-regulated proteins. In CIS, 2 up-regulated and 11 down-regulated proteins were identified. One of these proteins (Apolipoprotein A1) was confirmed by immunoblot. Though the pathophysiological role of these proteins still remains to be elucidated in detail and further validation is needed, these findings may have a relevant impact on the identification of disease-specific markers.

Proteome analysis of cerebrospinal fluid in Guillain–Barré syndrome (GBS)

We used two-dimensional difference in-gel electrophoresis (2-D-DIGE) for proteome analysis of cerebrospinal fluid (CSF) in Guillain-Barré syndrome (GBS). Spots showing >2-fold difference between GBS and controls were analysed using MALDI-TOF mass spectrometry. Proteins that were up-regulated in GBS included haptoglobin, serine/threonine kinase 10, alpha-1-antitrypsin, SNC73, alpha II spectrin, IgG kappa chain and cathepsin D preprotein, while transferrin, caldesmon, GALT, human heat shock protein 70, amyloidosis patient HL-heart-peptide 127aa and transthyretin were down-regulated. Some of these proteins are reported in CSF of GBS for the first time. Accordingly, the 2-D-DIGE technology may be useful to identify disease-specific proteins in patients with GBS.

Axonal damage markers in cerebrospinal fluid are increased in ALS

OBJECTIVE

To test whether biomarkers for axonal degeneration correlated with clinical subtypes and were of use in predicting progression of ALS.

METHODS

Patients with ALS (n = 69), patients with Alzheimer disease (AD; n = 73), and age-matched controls (n = 33) were included in this prospective study. CSF levels of tau protein and neurofilaments (NfHSMI35) were measured using ELISA. In 49 patients with ALS, follow-up data were available (median follow-up 7 months).

RESULTS

CSF levels of NfHSMI35 were five times higher in patients with ALS (1.7 ng/mL) than in controls (0.3 ng/mL, p < 0.001) and 10 times higher than in patients with AD (0.14 ng/mL, p < 0.001). NfHSMI35 values were also higher in patients with upper motor neuron-dominant ALS than in patients with typical ALS (upper motor neuron + lower motor neuron) at p = 0.02. Values of NfHSMI35 were higher in ALS of more rapid progression. The values of NfH and tau did not correlate with CSF protein content.

CONCLUSIONS

The authors propose that axonal damage markers in CSF may discriminate between subtypes of ALS and that they could be used as markers for therapeutic trials. CSF NfH was superior to tau in these discriminations.

The advanced glycation end-product Nɛ-(carboxymethyl)lysine level is elevated in cerebrospinal fluid of patients with amyotrophic lateral sclerosis

Oxidative stress is involved in the aetiopathogenesis of amyotrophic lateral sclerosis (ALS), a fatal degenerative disorder. To test whether oxidative stress in ALS is increased and confined to the central nervous system, we have measured the glycoxidation product N(epsilon)-(carboxymethyl)lysine (CML) in serum and cerebrospinal fluid (CSF) samples by means of a novel enzyme immunoassay. Significant increases of CSF/serum ratio of CML in ALS patients (n = 25) as compared to normal controls (n = 20, p = 0.001) and to Alzheimer disease patients (n = 9, p = 0.029) suggest intrathecal production of this glycoxidation product. Measurement of CML levels may provide a novel diagnostic tool and may supplement current monitoring strategies in interventional trials.

Tau protein in cerebrospinal fluid (CSF): a blood-CSF barrier related evaluation in patients with various neurological diseases

Tau protein (tau) is primarily localised in neurons, and after brain parenchymal damage its release into cerebrospinal fluid (CSF) is increased. The particular influences of blood-CSF barrier function and of disease topography on CSF tau levels have not been studied yet. CSF tau concentrations determined by enzyme-immunoassay in various neurological diseases (n = 61) were not dependent upon blood-CSF barrier dysfunction. Significant elevation of tau levels in patients with meningoencephalitis and cerebral hemorrhage indicates brain parenchymal damage. In contrast, tau levels remained normal in patients with bacterial meningitis if encephalitic complications did not occur. In patients with Guillain-Barré syndrome tau levels were low. Increased tau levels in active multiple sclerosis compared to clinically nonactive states indicate axonal pathology in active disease.

Aggregation substance promotes adherence, phagocytosis, and intracellular survival of Enterococcus faecalis within human macrophages and suppresses respiratory burst

The aggregation substance (AS) of Enterococcus faecalis, encoded on sex pheromone plasmids, is a surface-bound glycoprotein that mediates aggregation between bacteria thereby facilitating plasmid transfer. Sequencing of the pAD1-encoded Asa1 revealed that this surface protein contains two RGD motifs which are known to ligate integrins. Therefore, we investigated the influence of AS on the interaction of E. faecalis with human monocyte-derived macrophages which constitutively express beta(2) integrins (e.g., CD18). AS was found to cause a greater-than-fivefold increase in enterococcal adherence to macrophages and a greater-than-sevenfold increase in phagocytosis. Adherence was mediated by an interaction between the RGD motif and the integrin CD11b/CD18 (complement receptor type 3) as demonstrated by inhibition studies with monoclonal antibodies and RGD peptide. AS-bearing enterococci were significantly more resistant to macrophage killing during the first 3 h postinfection, probably due to inhibition of the respiratory burst as indicated by reduced concentrations of superoxide anion.