CSF and plasma biomarkers in cerebral amyloid angiopathy: A single-center study and a systematic review/meta-analysis.

INTRODUCTION: There are limited data regarding cerebrospinal fluid (CSF) and plasma biomarkers among patients with Cerebral Amyloid Angiopathy (CAA). We sought to investigate the levels of four biomarkers [ß-amyloids (Aß42 and Aß40), total tau (tau) and phosphorylated tau (p-tau)] in CAA patients compared to healthy controls (HC) and patients with Alzheimer Disease (AD). PATIENTS AND METHODS: A systematic review and meta-analysis of published studies, including also a 5 year single-center cohort study, with available data on CSF and plasma biomarkers in symptomatic sporadic CAA versus HC and AD was conducted. Biomarkers' comparisons were investigated using random-effects models based on the ratio of mean (RoM) biomarker concentrations. RoM < 1 and RoM > 1 indicate lower and higher biomarker concentration in CAA compared to another population, respectively. RESULTS: We identified nine cohorts, comprising 327 CAA patients (mean age: 71 ± 5 years; women: 45%) versus 336 HC (mean age: 65 ± 5 years; women: 45%) and 384 AD patients (mean age: 68 ± 3 years; women: 53%) with available data on CSF biomarkers. CSF Aß42 levels [RoM: 0.47; 95% CI: 0.36-0.62; p < 0.0001], Aß40 levels [RoM: 0.70; 95% CI: 0.63-0.79; p < 0.0001] and the ratio Aß42/Aß40 [RoM: 0.62; 95% CI: 0.39-0.98; p = 0.0438] differentiated CAA from HC. CSF Aß40 levels [RoM: 0.73; 95% CI: 0.64-0.83; p = 0.0003] differentiated CAA from AD. CSF tau and p-tau levels differentiated CAA from HC [RoM: 1.71; 95% CI: 1.41-2.09; p = 0.0002 and RoM: 1.44; 95% CI: 1.20-1.73; p = 0.0014, respectively] and from AD [RoM: 0.65; 95% CI: 0.58-0.72; p < 0.0001 and RoM: 0.64; 95% CI: 0.57-0.71; p < 0.0001, respectively]. Plasma Aß42 [RoM: 1.14; 95% CI: 0.89-1.45; p = 0.2079] and Aß40 [RoM: 1.07; 95% CI: 0.91-1.25; p = 0.3306] levels were comparable between CAA and HC. CONCLUSIONS: CAA is characterized by a distinct CSF biomarker pattern compared to HC and AD. CSF Aß40 levels are lower in CAA compared to HC and AD, while tau and p-tau levels are higher in CAA compared to HC, but lower in comparison to AD patients.

Peripheral Neuropathy in Patients with Hepatitis C Infection-Reversibility after HCV Eradication: A Single Center Study.

Chronic hepatitis C virus (HCV) infection is characterized by a variety of extra-hepatic manifestations; peripheral neuropathy (PN) is one of the most common, especially when mixed cryoglobulinemia (MCG) is present. The prevalence and risk factors of HCV-related PN in the absence of MCG are largely unknown. We conducted a prospective, single-center study, examining the prevalence and reversibility of HCV-associated neuropathy in the absence of MCG. Nerve fiber density in the epidermis was evaluated through skin biopsy and electroneurography (ENG) before HCV-treatment initiation and 1 year post sustained virological remission (SVR). Forty HCV-infected individuals (nine HIV co-infected) with no other neuron-harming factors were included; four other HCV mono- and three HIV co-infected individuals were excluded due to presence of diabetes, B12 insufficiency, or neurotoxic drugs. Twelve consecutive controls with no neuron-harming conditions were also recruited; eight more were excluded due to meeting exclusion criteria. Four patients had ENG signs of polyneuropathy (two with HCV mono- and two with HIV co-infection), while seven more (five with HCV mono- and two with HIV co-infection) had signs of mono-neuropathy, leading to PN prevalences of 22.5% and 44% for mono- and co-infection, respectively (p value 0.179). The two patients with HCV mono-infection and polyneuropathy and the one with ulnar nerve damage showed ENG improvement 1 year post SVR. Regarding intraepidermal nerve density, HCV infection, irrespective of HIV co-infection, was correlated with a lower intraepidermal neuron density that improved 1 year post SVR (p value 0.0002 for HCV and 0.0326 for HCV/HIV co-infected patients). PN is common in HCV infection; successful eradication of HCV leads to PN improvement.

The Dynamic Relationship between the Glymphatic System, Aging, Memory, and Sleep.

The process of memory entails the activation of numerous neural networks and biochemical pathways throughout the brain. The phenomenon of memory decline in relation to aging has been the subject of extensive research for several decades. The correlation between the process of aging and memory is intricate and has various aspects to consider. Throughout the aging process, there are various alterations that take place within the brain and, as expected, affect other functions that have already been linked to memory and its function such as involving microcirculation and sleep. Recent studies provide an understanding of how these mechanisms may be interconnected through the relatively new concept of the glymphatic system. The glymphatic system is strongly correlated to sleep processes. Sleep helps the glymphatic system remove brain waste solutes. Astrocytes expand and contract to form channels for cerebrospinal fluid (CSF) to wash through the brain and eliminate waste. However, the details have not been totally elusive, but the discovery of what we call the glymphatic system enables us to connect many pieces of physiology to understand how such factors are interconnected and the interplay between them. Thus, the purpose of this review is to discuss how the glymphatic system, sleep, memory, and aging are interconnected through a network of complex mechanisms and dynamic interactions.

Assessment of Aggregated and Exosome-Associated α-Synuclein in Brain Tissue and Cerebrospinal Fluid Using Specific Immunoassays.

Even though it is currently well-established that α-synuclein aggregation is closely associated with the pathological events in Parkinson's disease (PD) and several other neurodegenerative disorders, collectively called synucleinopathies, the mechanistic link between α-synuclein aggregates and the onset and progression of neurodegeneration in these diseases remain unclear. The process of aggregation initiates from a structurally distorted monomer that gradually oligomerizes to generate a repertoire of fibrillar and oligomeric multimers that deposit within diseased cells in the brain. Total α-synuclein has been proposed as a potential biomarker in PD, but most of the studies do not discriminate between distinct α-synuclein conformers. To correlate protein measurements to disease pathology, we have developed a conformation-specific ELISA method that selectively detects fibrillar and oligomeric forms of α-synuclein without cross-reacting with monomers. We have used this assay to determine the levels of aggregated α-synuclein in human and mouse brain tissue as well as in CSF and CSF-derived exosomes from patients with synucleinopathy and control subjects. Our results verify the ability of the new assay to detect aggregated α-synuclein in complex matrices and support the idea that the levels of these conformers are related to the age of onset in PD patients, while CSF analysis showed that these species exist in low abundance in CSF and CSF-derived exosomes. Future studies will be required to fully assess the diagnostic usefulness of this ELISA in synucleinopathies.

Recognizing Atypical Presentations of Alzheimer's Disease: The Importance of CSF Biomarkers in Clinical Practice.

Besides the typical amnestic presentation, neuropathological studies indicate that Alzheimer's disease (AD) may present with atypical clinical pictures. The relative frequencies of typical and atypical or mixed presentations within the entire spectrum of AD remain unclear, while some mixed or atypical presentations may have not received adequate attention for them to be included in diagnostic criteria. We investigated the spectrum of clinical presentations in patients with the AD CSF biomarker profile (high tau and phospho-tau, low Aß42 levels), hospitalized in a tertiary academic center. Among 98 patients with the CSF AD profile, 46% of patients had the typical presentation of "hippocampal" amnestic dementia. Additionally, 23.5% and 15.3% fulfilled the criteria of mixed or atypical presentations, respectively, as described in the IWG-2 criteria. The remaining 15.3% had unusual presentations, including non-logopenic (semantic and non-fluent agrammatic) primary progressive aphasia, corticobasal syndrome, and Richardson syndrome, or could be diagnosed with normal pressure hydrocephalus. Despite selection bias (academic center), atypical clinical presentations of AD may be more common than previously thought. CSF biomarkers seem to be a useful tool for antemortem identification of such patients, which is likely to affect therapeutic decisions. Some of the unusual presentations described above should be incorporated in diagnostic criteria.

Plasma P-Tau181 for the Discrimination of Alzheimer's Disease from Other Primary Dementing and/or Movement Disorders.

Blood phospho-tau181 may offer a useful biomarker for Alzheimer's disease. However, the use of either serum or plasma phospho-tau181 and their diagnostic value are currently under intense investigation. In a pilot study, we measured both serum and plasma phospho-tau181 (pT181-Tau) by single molecule array (Simoa) in a group of patients with Alzheimer's disease and a mixed group of patients with other primary dementing and/or movement disorders. Classical cerebrospinal fluid biomarkers were also measured. Plasma (but not serum) pT181-Tau showed a significant increase in Alzheimer's disease and correlated significantly with cerebrospinal fluid amyloid and pT181-Tau. Receiver operating curve analysis revealed a significant discrimination of Alzheimer's from non-Alzheimer's disease patients, with an area under the curve of 0.83 and an excellent sensitivity but a moderate specificity. Plasma pT181-Tau is not an established diagnostic biomarker for Alzheimer's disease, but it could become one in the future, or it may serve as a screening tool for specific cases of patients or presymptomatic subjects.

Plasma Phospho-Tau-181 as a Diagnostic Aid in Alzheimer's Disease.

Cerebrospinal fluid (CSF) biomarkers remain the gold standard for fluid-biomarker-based diagnosis of Alzheimer's disease (AD) during life. Plasma biomarkers avoid lumbar puncture and allow repeated sampling. Changes of plasma phospho-tau-181 in AD are of comparable magnitude and seem to parallel the changes in CSF, may occur in preclinical or predementia stages of the disease, and may differentiate AD from other causes of dementia with adequate accuracy. Plasma phospho-tau-181 may offer a useful alternative to CSF phospho-tau determination, but work still has to be done concerning the optimal method of determination with the highest combination of sensitivity and specificity and cost-effect parameters.

Classical Cerebrospinal Fluid Biomarkers in Dementia with Lewy Bodies.

The use and interpretation of diagnostic cerebrospinal fluid (CSF) biomarkers for neurodegenerative disorders, such as Dementia with Lewy bodies (DLB), represent a clinical challenge. According to the literature, the composition of CSF in DLB patients varies. Some patients present with reduced levels of amyloid, others with full Alzheimer Disease CSF profile (both reduced amyloid and increased phospho-tau) and some with a normal profile. Some patients may present with abnormal levels of a-synuclein. Continuous efforts will be required to establish useful CSF biomarkers for the early diagnosis of DLB. Given the heterogeneity of methods and results between studies, further validation is fundamental before conclusions can be drawn.

Type 2 Diabetes Mellitus as a Risk Factor for Alzheimer's Disease: Review and Meta-Analysis.

Alzheimer's disease is the most common type of dementia, reaching 60-80% of case totals, and is one of the major global causes of the elderly population's decline in functionality concerning daily life activities. Epidemiological research has already indicated that, in addition to several others metabolic factors, diabetes mellitus type 2 is a risk factor of Alzheimer's disease. Many molecular pathways have been described, and at the same time, there are clues that suggest the connection between type 2 diabetes mellitus and Alzheimer's disease, through specific genes, autophagy, and even inflammatory pathways. A systematic review with meta-analysis was conducted, and its main goal was to reveal the multilevel connection between these diseases.

CADASIL in Greece: Mutational spectrum and clinical characteristics based on a systematic review and pooled analysis of published cases.

BACKGROUND: Differences have been noted in the clinical presentation and mutational spectrum of CADASIL among various geographical areas. The aim of the present study was to investigate the mode of clinical presentation and genetic mutations reported in Greece. METHODS: After a systematic literature search, we performed a pooled analysis of all published CADASIL cases from Greece. RESULTS: We identified 14 studies that reported data from 14 families comprising 54 patients. Migraine with aura was reported in 39%, ischemic cerebrovascular diseases in 68%, behavioral-psychiatric symptoms in 47% and cognitive decline in 60% of the patients. The mean (±SD) age of onset for migraine with aura, ischemic cerebrovascular diseases, behavioral-psychiatric symptoms and cognitive decline was 26.2 ± 8.7, 49.3 ± 14.6, 47.9 ± 9.4 and 42.9 ± 10.3, respectively; the mean age at disease onset and death was 34.6 ± 12.1 and 60.2 ± 11.2 years. With respect to reported mutations, mutations in exon 4 were the most frequently reported (61.5% of all families), with the R169C mutation being the most common (30.8% of all families and 50% of exon 4 mutations), followed by R182C mutation (15.4% of all families and 25% of exon 4 mutations). CONCLUSIONS: The clinical presentation of CADASIL in Greece is in accordance with the phenotype encountered in Caucasian populations, but differs from the Asian phenotype, which is characterized by a lower prevalence of migraine and psychiatric symptoms. The genotype of Greek CADASIL pedigrees is similar to that of British pedigrees, exhibiting a high prevalence of exon 4 mutations, but differs from Italian and Asian populations, where mutations in exon 11 are frequently encountered.

From Cerebrospinal Fluid Neurochemistry to Clinical Diagnosis of Alzheimer's Disease in the Era of Anti-Amyloid Treatments. Report of Four Patients.

Analysis of classical cerebrospinal fluid biomarkers, especially when incorporated in a classification/diagnostic system such as the AT(N), may offer a significant diagnostic tool allowing correct identification of Alzheimer's disease during life. We describe four patients with more or less atypical or mixed clinical presentation, in which the classical cerebrospinal fluid biomarkers amyloid peptide with 42 and 40 amino acids (Aß42 and Aß40, respectively), phospho-tau (τP-181) and total tau (τΤ) were measured. Despite the unusual clinical presentation, the biomarker profile was compatible with Alzheimer's disease in all four patients. The measurement of classical biomarkers in the cerebrospinal fluid may be a useful tool in identifying the biochemical fingerprints of Alzheimer's disease, especially currently, due to the recent approval of the first disease-modifying treatment, allowing not only typical but also atypical cases to be enrolled in trials of such treatments.

Blood Biomarkers in Frontotemporal Dementia: Review and Meta-Analysis.

Biomarkers in cerebrospinal fluid (CSF) are useful in the differential diagnosis between frontotemporal dementia (FTD) and Alzheimer's dementia (AD), but require lumbar puncture, which is a moderately invasive procedure that can cause anxiety to patients. Gradually, the measurement of blood biomarkers has been attracting great interest. Testing blood instead of CSF, in order to measure biomarkers, offers numerous advantages because it negates the need for lumbar puncture, it is widely available, and can be repeated, allowing the prediction of disease course. In this study, a systematic review of the existing literature was conducted, as well as meta-analysis with greater emphasis on the most studied biomarkers, p-tau and progranulin. The goal was to give prominence to evidence regarding the use of plasma biomarkers in clinical practice.

Cerebrospinal fluid biomarkers and apolipoprotein E genotype in cerebral amyloid angiopathy. A narrative review.

Sporadic cerebral amyloid angiopathy (CAA) is a cerebral small vessel disease, characterized by the deposition of ß-amyloid within the cortical and leptomeningeal blood vessel walls. It has attracted interest concerning new therapeutic perspectives. However, there are scarce data regarding the cerebrospinal fluid biomarkers (CSF) and genetic factors in sporadic CAA. In this narrative review, we investigated the literature regarding the cerebrospinal fluid core biomarkers profile of patients with probable or possible CAA and its subtype, the CAA- related inflammation (CAA-ri), taking into account the clinical and radiological characteristics of the patients. We also analyzed the Apolipoprotein E (APOE) genotype differentiations among the different subtypes of cerebral amyloid angiopathy. Our results demonstrate specific CSF patterns of ß-amyloid (Aß42 and Aß40) and tau-proteins (t-tau and p-tau) which may serve as molecular biomarkers for CAA/ CAA-ri and could prove helpful for novel therapeutic procedures. Specifically, decreased levels of Aß40 and Aß42 in both CAA and CAA-ri, mildly increased concentrations of tau protein in patients with CAA-ri and a strong association between APOE ε4/ε4 genotype and CAA-ri are the main findings.

Diffuse glioma manifesting as normal pressure hydrocephalus: A potential pitfall in diagnosis-a case report.

•Hydrocephalus is rarely reported in patients with diffuse glioma.•We describe a patient with a low-grade glioma presenting a complex phenotype initially masquerading as hydrocephalus of unknown etiology.•The exact pathophysiological mechanism underlying hydrocephalus in the setting of diffuse glioma remains to be elucidated.•Caution is advised regarding hydrocephalus of unknown etiology, reevaluation is necessary.

Poor stroke risk perception despite moderate public stroke awareness: insight from a cross-sectional national survey in Greece.

BACKGROUND: Although stroke is the fourth cause of death in Western societies, public stroke awareness remains suboptimal. The aim of this study was to estimate stroke risk perception and stroke awareness in Greece through a cross-sectional telephone survey. METHODS: A trained interview team conducted this cross-sectional telephone survey between February and April 2014 using an online structured questionnaire. Participants were selected using random digit dialing of landline and mobile telephone numbers with quota sampling weighted for geographical region based on the most recent General Population Census (2011). RESULTS: Between February and April 2014, 723 individuals (418 women [58%], 47.4 ± 17.8 years) agreed to respond. Among all respondents, 642 (88.8%) were able to provide at least 1 stroke risk factor; 673 respondents (93.08%) were able to provide correctly at least 1 stroke symptom or sign. When asked what would they do in case of acute onset of stroke symptoms, 497 (68.7%) responded that they would either call the ambulance or visit the closest emergency department. Only 35.3%, 18.9%, 17.2%, 20.7%, and 15.0% of respondents with atrial fibrillation, arterial hypertension, dyslipidemia, diabetes mellitus, and current smoking, respectively, considered themselves as being in high risk for stroke. CONCLUSIONS: Stroke risk perception in Greece is low despite moderate public stroke awareness.