Creutzfeldt-Jakob disease and homocysteine levels in plasma and cerebrospinal fluid

Background: There is evidence that homocysteine contributes to various neurodegenerative disorders. Objective: To assess the values of homocysteine in patients with Creutzfeldt-Jakob disease (CJD) in both cerebrospinal fluid (CSF) and plasma. Methods: Study design: Case control study. Total homocysteine was quantified in CSF and plasma samples of CJD patients (n = 13) and healthy controls (n = 13). Results: Mean values in healthy controls: 0.15 mumol/l +/- 0.07 (CSF) and 9.10 mumol/l +/- 2.99 (plasma); mean values in CJD patients: 0.13 mumol/l +/- 0.03 (CSF) and 9.22 mumol/l +/- 1.81 (plasma). No significant differences between CJD patients and controls were observed (Mann-Whitney U, p > 0.05). Conclusions: The results indicate that the CSF and plasma of CJD patients showed no higher endogenous levels of homocysteine as compared to normal healthy controls. These findings provide no evidence for an additional role of homocysteine in the pathogenetic mechanisms underlying CJD neurodegeneration. Copyright (C) 2005 S. Karger AG, Basel

Prion Protein Strain Diversity and Disease Pathology

The infectious agents, prions, are composed mainly of conformational isomers of the cellular prion protein (PrPc) in its abnormal accumulated scrapie forms (PrPSc). The distinct prion isolates or strains have been associated with different PrPSc prion protein conformations and patterns of glycosylation and are associated with disease progression and severity. In humans, sporadic Creutzfeldt-Jakob disease (sCJD) is the most common form and has been divided into six subtypes, based on PrPSc electrophoretic mobility and allelic variation at codon 129, among which sCJD MM1 and sCJD VV2 are the two most commonly occurring subtypes with known clinical manifestations. The strain-specific response of PrPSc suggests both the molecular classification and the pathogenesis of prion diseases along with posttranslational modification of PrP in humans and animals

Steroid-responsive encephalopathy in autoimmune thyroiditis (SREAT) as a differential diagnosis of Creutzfeldt-Jakob disease

Introduction. Steroid-responsive encephalopathy in autoimmune thyroiditis (SREAT) is characterised by a wide range of neuropsychiatric symptoms and elevated thyroid antibodies. SREAT can mimic sporadic Creutzfeldt-Jakob disease (sCJD) and distinguishing between both entities is important because SREAT responds to corticosteroids. Material and methods. Data of patients reported to the National Reference Centre for the Surveillance of CJD in Göttingen, Germany between August 1994 and October 2008 was retrospectively reviewed. In the case and control groups, 49 patients had SREAT and 48 had sCJD with elevated thyroid antibodies. Results. Antibodies against thyroid peroxidase were the most common antibodies in both SREAT (86%) and sCJD (88%), followed by antibodies against thyroglobulin (SREAT, 63.3%; sCJD, 39.6%; p = 0.020) and TSH-receptor-antibodies (SREAT, 14.3%; sCJD, 2.1%; p = 0.059). Epileptic seizures were observed more frequently in the SREAT group (SREAT, 44.9%; sCJD, 12.5%; p < 0.001). Dementia (SREAT, 61.2%; sCJD, 100%; p < 0.001), ataxia (SREAT, 44.9%; sCJD, 89.6%; p < 0.001), visual impairment (SREAT, 22.4%; sCJD, 50%; p = 0.005), extrapyramidal disorder (SREAT, 32.7%; sCJD, 60.4%; p = 0.006), myoclonus (SREAT, 38.8%; sCJD, 81.3%; p < 0.001) and akinetic mutism (SREAT, 6.1%; sCJD, 37.5%; p < 0.001) were observed more frequently in sCJD. Cerebrospinal fluid (CSF) pleocytosis was observed more frequently in SREAT patients (SREAT, 33.3%; sCJD, 6.4%; p = 0.001), as was a pathological increase in protein concentration (SREAT, 68.8%; sCJD, 36.2%; p = 0.001). Conclusions. In a case of encephalopathy, the diagnosis of SREAT should also be considered in suspected cases of CJD so as to be able to start corticosteroid treatment quickly

Clinical Features of Rapidly Progressive Alzheimer's Disease

Objective: To characterize clinical features, CSF biomarkers and genetic polymorphisms of patients suffering from a rapidly progressing subtype of Alzheimer's dementia (rpAD). Methods: Retrospective analyses of 32 neuropathologically confirmed cases differentially diagnosed as AD out of a group with rapidly progressive dementia. CSF biomarkers (14-3-3, tau, beta-amyloid 1-42) and genetic markers (PRNP codon 129, apolipoprotein E, ApoE, polymorphism) were determined. Results: Median survival was 26 months, age at onset 73 years. Biomarkers: mean beta-amyloid 1-42: 266 pg/ml, median tau: 491 pg/ml, 14-3-3 positive: 31%. Genetic polymorphisms showed a predominance of methionine homozygosity at PRNP codon 129 and a low frequency of ApoE4 (38%, no homozygous patients). Thirty-five symptoms were studied. Frequent symptoms were myoclonus (75%), disturbed gait (66%) and rigidity (50%). Discussion: rpAD is associated with a diversity of neurological signs even able to mimic Creutz feldt-Jakob disease. Biomarkers and genetic profile differ from those seen in classical AD. The findings on biomarkers, symptomatology and genetics may aid the differential diagnostic process. Copyright (C) 2010 S. Karger AG, Base

Oligodendroglial Process Formation is Differentially Affected by Modulating the Intra- and Extracellular Cholesterol Content

Cholesterol is an essential component of eukaryotic plasma membranes and plays an important role in membrane organization and signaling processes. It is the major lipid component of detergent resistant caveolin-1 containing rafts which previously had been reported as a platform for nerve growth factor (NGF) signaling in oligodendrocytes (OL). Surprisingly, a knockdown of caveolin-1 attenuated the process formation of OL (Schmitz et al. J Neurosci Res 88:572–588, 2010), for which a loss of cholesterol could be responsible. In the present report, we could show that a caveolin-1 knockdown resulted in an elevation of cellular cholesterol level; it may indicate an important role of caveolin-1 in cholesterol trafficking to the plasma membrane. Treatment with exogenous PEG cholesterol, which was incorporated to the plasma membrane, supported oligodendroglial process formation, in particular when OL were stimulated by NGF. In this context we have found that OL express NPC1L1 (Niemann–Pick disease type C1-Like 1) which could modulate cholesterol uptake. In contrast, depletion of membrane-bound cholesterol diminished NGF-induced process formation concomitant with a reduced activity of p42/44 mitogen-activated protein kinases

Tau Protein as a Biological Fluid Biomarker in Neurodegenerative Dementias

Tau is a microtubule-associated protein, whose main function is the modulation of the stability of axonal microtubules. In physiological conditions tau is abundant in neurons while its expression in glial populations is low and restricted to astrocytes and oligodendrocytes. The aggregation of tau in neurofibrillary or gliofibrillary tangles is the main hallmark of tauopathies, a complex group of human neurodegenerative conditions where tau hyper-phosphorylation causes its increased insolubility and aggregation leading to tangle formation and microtubule destabilization. Tau can be detected in biological fluids in physiological and pathological conditions. In several neurodegenerative dementias, either associated or not to a primary tauopathy, tau levels are altered in a disease-specific pattern, which can be used as a biomarker for disease diagnosis and prognosis. The study of tau levels in biological fluids has been mainly performed in the cerebrospinal fluid (CSF), although the recent development of ultrasensitive techniques allows the robust quantification of tau in blood-based biofluids such as serum and plasma. The presence of elevated total-tau in the CSF is assumed to reflect the degree of axonal damage in the brain tissue. Consequently, highest total-tau CSF levels are found in sporadic Creutzfeldt-Jakob disease, which is characterized by massive neuronal damage and a rapid progressive course. Elevated total-tau is also detected in Alzheimer’s disease and dementia with Lewy bodies, while in other dementia conditions such as vascular dementia, frontotemporal dementia and corticobasal degeneration are unchanged, inconclusive or not determined. Additionally, total-tau rises temporarily due to cerebral infarction. In contrast, elevated phospho-tau levels seem to be restricted to Alzheimer’s disease pathology, most likely mirroring the presence of the hyper-phosphorylated form in the brain tissue, although phospho-tau levels are mainly unaffected in tauopathies. Additionally, isoforms and different structural and truncated tau forms have also been reported to be altered in neurodegenerative dementias. In this complex scenario the diagnostic accuracy of diverse tau forms as disease-specific biomarkers needs to be established. In this chapter, we summarize the current knowledge on the alterations of diverse tau forms in biological fluids of neurodegenerative dementias and its relevance in the differential diagnostic context. Additionally, we explore how tau alterations in the brain tissue may explain the etiology of its regulated levels in CSF and blood

Cerebrospinal fluid biomarkers in Alzheimer’s disease, vascular dementia and ischemic stroke patients: a critical analysis

Vascular factors are thought to contribute to the development of disease pathology in neurodegenerative dementia such as Alzheimer’s disease (AD). Another entity, called vascular dementia (VaD), comprises a less defined group of dementia patients having various vascular diseases that especially emerge in the elderly population and require valid options for examination and differential diagnosis. In the context of a retrospective study, we analyzed the cerebrospinal fluid (CSF) biomarkers t-tau, p-tau and Aß42 of a total of 131 patients with AD (n = 47), mild cognitive impairment (MCI) (n = 22), VaD (n = 44) and stroke (n = 18). We found a remarkable alteration in CSF biomarker profile in AD, VaD and in acute ischemic events. CSF profile in AD patients was altered in a very similar way as in stroke patients, without statistical differences. In stroke, increase depend largely on size and duration after the initial event. Total tau levels were useful to differ between VaD and stroke. Aß42 decreased in a similar way in AD, VaD and stroke and had a trend to lower levels in MCI but not in controls