Peter Lange

α-Synuclein in human cerebrospinal fluid is principally derived from neurons of the central nervous system.

The source of Parkinson disease-linked α-synuclein (aSyn) in human cerebrospinal fluid (CSF) remains unknown. We decided to measure the concentration of aSyn and its gradient in human CSF specimens and compared it with serum to explore its origin. We correlated aSyn concentrations in CSF versus serum (QaSyn) to the albumin quotient (Qalbumin) to evaluate its relation to blood–CSF barrier function. We also compared aSyn with several other CSF constituents of either central or peripheral sources (or both) including albumin, neuron-specific enolase, β-trace protein and total protein content. Finally, we examined whether aSyn is present within the structures of the choroid plexus (CP). We observed that QaSyn did not rise or fall with Qalbumin values, a relative measure of blood–CSF barrier integrity. In our CSF gradient analyses, aSyn levels decreased slightly from rostral to caudal fractions, in parallel to the recorded changes for neuron-specific enolase; the opposite trend was recorded for total protein, albumin and β-trace protein. The latter showed higher concentrations in caudal CSF fractions due to the diffusion-mediated transfer of proteins from blood and leptomeninges into CSF in the lower regions of the spine. In postmortem sections of human brain, we detected highly variable aSyn reactivity within the epithelial cell layer of CP in patients diagnosed with a range of neurological diseases; however, in sections of mice that express only human SNCA alleles (and in those without any Snca gene expression), we detected no aSyn signal in the epithelial cells of the CP. We conclude from these complementary results that despite its higher levels in peripheral blood products, neurons of the brain and spinal cord represent the principal source of aSyn in human CSF.

Intrathecal antibody production against Epstein-Barr and other neurotropic viruses in pediatric and adult onset multiple sclerosis

Epstein-Barr virus (EBV) has been implicated in the pathogenesis of multiple sclerosis (MS). Recent reports proposed an increased EBV-targeted humoral immune response in MS, which appears to be more pronounced in pediatric patients. However, little is known about the CNS-derived antibody production against EBV in patients with MS. The objective of this study was to assess the frequency and intensity of intrathecal antibody production against EBV as compared to other neurotropic viruses in pediatric and adult onset MS. In cohorts of 43 childhood, 50 adult onset MS patients, 20 children and 12 adults with other CNS disorders, paired CSF and serum samples were studied. Frequency and intensity of intrathecal antibody production against EBV as compared to measles, rubella, varicella zoster (VZV) and herpes simplex virus (HSV) were analyzed by determination of virus-specific CSF-to-serum Antibody Indices (AI). Intrathecally synthesized EBV antibodies were detectable in 26% pediatric and 10% adult onset MS patients, compared to frequencies ranging in both groups from 10 to 60% for the other viruses. Median AIs for EBV were lower than those for all other viruses, with more than twofold higher median AI for measles, rubella and VZV. The EBV-targeted humoral immune response in the CNS is only part of the intrathecal polyspecific antibody production in MS, directed against various neurotropic viruses. Our results do not rule out the possibility that EBV is involved in the pathogenesis of MS by triggering diverse cellular immune mechanisms, but they argue against a direct pathogenic role of EBV-targeted humoral immune response within the CNS.

Dexamethasone increases hippocampal neuronal apoptosis in a rabbit model of Escherichia coli meningitis

Mortality and long-term sequelae rates are high among adults and children with acute bacterial meningitis. Adjunctive treatment with dexamethasone has been shown to reduce systemic complications in bacterial meningitis patients, but corticosteroid treatment may have detrimental effects on hippocampal function. We evaluated the effect of dexamethasone treatment in addition to antibiotic therapy in a rabbit model of Escherichia coli meningitis. A moderate anti-inflammatory effect of dexamethasone could be demonstrated with respect to the inflammatory mediator prostaglandin E2, whereas no significant effect of dexamethasone on tumor necrosis factor-α, cerebrospinal fluid pleocytosis, protein, lactate, indicators of global neuronal damage, or blood gas analysis was found. Dexamethasone, however, increased the rate of apoptotic neurons in the granular layer of the hippocampal dentate gyrus. In view of the proapoptotic effect of adjunctive dexamethasone on hippocampal neuronal cells in animal models of Gram-positive and Gram-negative meningitis, the application of dexamethasone should be considered carefully in those forms of bacterial meningitis for which no evidence-based data of beneficial effect in humans are available, such as neonatal meningitis, bacillary Gram-negative meningitis or nosocomial forms of meningitis (e.g. following neurosurgery).

Biological markers for axonal degeneration in CSF and blood of patients with the first event indicative for multiple sclerosis

Axonal degeneration is now recognized as an important pathological feature of multiple sclerosis (MS). Acute axonal damage happens early in the disease course, and therefore early changes might occur in markers in body fluids, such as cerebrospinal fluid (CSF) and blood. In our study we investigated the relevance of serum and CSF markers for axonal damage in patients with clinically isolated syndrome indicative for MS. We measured the concentration of tau, phospho-tau, S100B, Amyloid beta and neuron specific enolase (NSE) in CSF and serum. Interestingly, the NSE concentration in CSF and serum was decreased in clinically isolated syndrome (CIS)-patients in comparison to the control group indicating reduced neuronal metabolic activity in the early stage of the disease. Concerning other biomarkers, we did not observe any changes in the concentrations between groups. Moreover, we did not detect any correlation between Expanded Disability Status Scale (EDSS) and the concentration of investigated proteins.

Tau, phospho-tau, and S-100B in the cerebrospinal fluid of children with multiple sclerosis.

Axonal injury and glial activation are an early neuropathologic event in adults with multiple sclerosis. To investigate whether markers of axonal injury and glial activation are already elevated in the cerebrospinal fluid of children with multiple sclerosis, we studied the cerebrospinal fluid of 25 children with multiple sclerosis and 67 controls for the presence of tau, phospho-tau, and S-100B proteins using specific enzyme-linked immunoabsorbent assays. In general, tau, phospho-tau, and S-100B protein levels did not differ significantly between groups. However, in a subgroup of nine children with multiple sclerosis, all of whom had prominent clinical symptoms at the time of lumbar puncture and radiologic disease activity, tau protein levels were significantly elevated when compared with other controls. These data indicate that axonal injury is not restricted to adult multiple sclerosis but can already occur in children with multiple sclerosis. ( J Child Neurol 2005;20:822—825).

Comparative analysis of cerebrospinal fluid biomarkers in the differential diagnosis of neurodegenerative dementia

The analysis of cerebrospinal fluid biomarkers gains importance in clinical routine and is effective in substantiating dementia diagnosis in the differential diagnostic context.

Inhibition of glutamine synthetase in rabbit pneumococcal meningitis is associated with neuronal apoptosis in the dentate gyrus

Apoptosis of dentate granular cells in the hippocampal formation during bacterial meningitis may be mediated by glutamate toxicity. For this reason, we studied the relationship between glutamine synthetase activity and regional neuronal apoptosis in rabbits with experimental pneumococcal meningitis. The duration of meningitis was 24 h, and the treatment was started 16 h after infection. Significant increases of glutamine synthetase protein concentration (P < 0.05) were found in the frontal cortex of rabbits with meningitis (n = 7) and rabbits with meningitis receiving ceftriaxone treatment (n = 12) as compared to the control animals (n = 14). No significant differences were seen in the hippocampal formation. The enzymatic activity of glutamine synthetase also was elevated in the frontal cortex (P < 0.05), but not in the hippocampal formation of rabbits with meningitis. After intravenous administration of L‐methionine sulfoximine (specific inhibitor of glutamine synthetase) in rabbits with meningitis treated with ceftriaxone (n = 10), the concentration of neuron‐specific enolase in CSF (P = 0.025) and the density of apoptotic neurons in the dentate gyrus quantified with the in‐situ tailing reaction (P = 0.043) were higher than in meningitic animals receiving only ceftriaxone (n = 10). In conclusion, the inability of hippocampal glutamine synthetase to metabolize excess amounts of glutamate may contribute to neuronal apoptosis in the hippocampal formation during meningitis. GLIA 30:11–18, 2000.

Fibronectin is elevated in the cerebrospinal fluid of patients suffering from bacterial meningitis and enhances inflammation caused by bacterial products in primary mouse microglial cell cultures.

Toll‐like receptors (TLR) play a key role in the recognition of pathogenic organisms. Fibronectin, an extracellular matrix protein, is considered a potent stimulator of the innate immune system through TLR4. In bacterial meningitis, several extracellular matrix proteins and bacterial compounds are elevated in the CSF. For this reason, we hypothesized that these molecules may jointly stimulate the innate immune system and increase neuronal damage in bacterial meningitis. Concentrations of fibronectin were elevated in the CSF of patients suffering from bacterial meningitis, but not in patients with multiple sclerosis, when compared with control patients without CSF abnormalities. In primary cultures of mouse microglial cells, co‐administration of fibronectin at concentrations occurring in the CSF in bacterial meningitis (10 μg/mL) with defined TLR agonists [lipopolysaccharide (TLR4), the synthetic lipopeptide tripalmytoyl‐cysteinyl‐seryl‐(lysyl)3‐lysine (TLR2) and single‐stranded unmethylated cytosine‐guanosine oligodesoxynucleotide (TLR9)] led to an additive release of nitric oxide and tumor necrosis factor‐alpha when compared with the release elicited by either compound alone. In conclusion, the inflammatory reaction to bacterial compounds can be aggravated by endogenous fibronectin at elevated levels during bacterial CNS infections. This additive or synergistic effect may contribute to neuronal damage during bacterial meningitis.

A soluble form of tumour necrosis factor receptor in cerebrospinal fluid and serum of HTLV-I-associated myelopathy and other neurological diseases

Paired samples of cerebrospinal fluid (CSF) and serum from 17 patients with human T-cell lymphotrophic virus I (HTLVI)-associated myelopathy, 5 patients with multiple sclerosis and 11 controls with non-inflammatory disorders (migraine, idiopathic epilepsy and myelopathy of unknown aetiology) were examined by enzyme-linked immunosorbent assay for the presence of the 60-kDa soluble form of tumour necrosis factor receptor (sTNF-R). The results were compared with blood-CSF barrier function, cell count and the intrathecal synthesis of HTLVI antibodies. No correlation could be demonstrated. High levels of sTNF-R were found in CSF of patients with HTLV-I-associated myelopathy and multiple sclerosis. In addition, intrathecal sTNF-R was also detected in the patients with non-inflammatory diseases, indicating that sTNF-R is definitively a normal constituent of CSF.

Using Cerebrospinal Fluid Marker Profiles in Clinical Diagnosis of Dementia with Lewy Bodies, Parkinson's Disease, and Alzheimer's Disease

BACKGROUND Dementia with Lewy bodies (DLB) is difficult to differentiate from other neuro-degenerative diseases. Patients are often mistaken to suffer from Parkinsons disease (PD) or Alzheimers disease (AD) because of the overlapping clinical appearances concerning cognition and movement. OBJECTIVE We investigated the possibility for a valid differential diagnosis using cerebrospinal fluid (CSF) biomarkers. METHODS In the context of a large retrospective study, we analyzed data of patients suffering from degenerative, ischemic, or inflammatory CNS (central nervous system) diseases and identified those with DLB (n = 34), PD (n = 37), and AD (n = 47) for further analyses. RESULTS We detected abnormalities in the CSF profiles of those patients with DLB while using a combination of decreased amyloid-β (Aβ)42 and increased tau levels. By stratification of data by disease severity, we observed a high sensitivity of this combination especially in the subgroup of patients with advanced stages, while the sensitivity in early forms was lower. In addition, with clinical deterioration, the abnormalities in the CSF profile became more pronounced. CONCLUSION We conclude that DLB can be distinguished from PD, in spite of both being synucleinopathies, by CSF profiles using neurodegenerative marker analysis. The pathophysiology of increased tau and decreased Aβ levels in those conditions has to be elucidated further, since both proteins are known to be involved in the pathogenesis of AD, but no clear explanation has been postulated for DLB yet.