Publications by authors named "Piotr Lewczuk"

Background: In the context of Alzheimer's disease (AD), blood‐based biomarkers have become increasingly important for various clinical purposes, such as screening patients and tracking the progression of the disease. Tau is a protein that stabilizes microtubules in nerve cells. In AD, different isoforms of tau become hyperphosphorylated, leading to the formation of neurofibrillary tangles, which are a key pathological feature of the AD.

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Background: The quantification of neurofilament light chain (NfL) in blood and cerebrospinal fluid (CSF) has proved useful in many contexts, for the diagnosis and prognosis of various neurological disorders. There is, however, a diversity of practices between centers, essentially linked to the context of use (COU), analytical methods, consideration of comorbidities, determination of cut‐points or use of interpretation scales. Finally, for the same biochemical profile, the interpretation and reporting of results may differ from one center to another, raising the question of test commutability.

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Background: Mental health and psychosocial support (MHPSS) is increasingly considered vital for addressing the needs of displaced communities. The mental health of young people in Lebanon, including members of the host community and refugees, has been severely affected by multiple crises. Physical activity (PA) is an effective means for enhancing mental health, but evidence of PA's impact on mental health among forcibly displaced populations is still emerging and often varies widely across studies.

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The number of patients with Alzheimer's Disease (AD) has increased rapidly in recent decades. AD is a complex progressive neurodegenerative disease affecting c.14 million patients in Europe and the United States.

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Background: Neuropsychiatric symptoms (NPS) are common in older people, may occur early in the development of dementia disorders, and have been associated with faster cognitive decline. Here, our objectives were to investigate whether plasma levels of neurofilament light chain (NfL), glial fibrillary acid protein (GFAP), and tau phosphorylated at threonine 181 (pTau181) are associated with current NPS and predict future NPS in non-demented older people. Furthermore, we tested whether the presence of NPS combined with plasma biomarkers are useful to predict Alzheimer's disease (AD) pathology and cognitive decline.

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Introduction: Soluble amyloid beta (Aβ) oligomers have been suggested as initiating Aβ related neuropathologic change in Alzheimer's disease (AD) but their quantitative distribution and chronological sequence within the AD continuum remain unclear.

Methods: A total of 526 participants in early clinical stages of AD and controls from a longitudinal cohort were neurobiologically classified for amyloid and tau pathology applying the AT(N) system. Aβ and tau oligomers in the quantified cerebrospinal fluid (CSF) were measured using surface-based fluorescence intensity distribution analysis (sFIDA) technology.

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Background: Neuropsychiatric symptoms (NPS) are common in older people, may occur early in the development of dementia disorders, and have been associated with faster cognitive decline. Here, our objectives were to investigate whether plasma levels of neurofilament light chain (NfL), glial fibrillary acid protein (GFAP), and tau phosphorylated at threonine 181 (pTau181) are associated with current NPS and predict future NPS in non-demented older people. Furthermore, we tested whether the presence of NPS combined with plasma biomarkers are useful to predict Alzheimer's disease (AD) pathology and cognitive decline.

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Blood phosphorylated tau (p-tau) biomarkers, including p-tau217, show high associations with Alzheimer's disease (AD) neuropathologic change and clinical stage. Certain plasma p-tau217 assays recognize tau forms phosphorylated additionally at threonine-212, but the contribution of p-tau212 alone to AD is unknown. We developed a blood-based immunoassay that is specific to p-tau212 without cross-reactivity to p-tau217.

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The significant role of increased activation of 20S proteasomes in the development of abdominal aortic aneurysms has been well-established in a mouse model. The available literature lacks similar studies concerning brain aneurysms. The aim of the study was to verify the hypothesis that patients with unruptured intracranial aneurysms (UIA) have increased 20S proteasome ChT-L activity compared to the control group of individuals without vascular lesions in the brain.

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Blood phosphorylated tau (p-tau) biomarkers, including p-tau217, show high associations with Alzheimer's disease (AD) neuropathologic change and clinical stage. Certain plasma p-tau217 assays recognize tau forms phosphorylated additionally at threonine-212, but the contribution of p-tau212 alone to AD is unknown. We developed a blood-based immunoassay that is specific to p-tau212 without cross-reactivity to p-tau217.

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Background: The established Erlangen Score (ES) for the interpretation of cerebrospinal fluid (CSF) biomarkers in the diagnostics of Alzheimer's disease (AD) uses markers of amyloidopathy and tauopathy, equally weighted to form an easy-interpretable ordinal scale. However, these biomarkers are not equally predictive for AD.

Objective: The higher weighting of the Aβ42/Aβ40 ratio, as a reconceptualized ERlangen Score (ERS), was tested for advantages in diagnostic performance.

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Integrating cerebrospinal fluid-biomarkers into diagnostic workup of patients with sporadic cerebral amyloid angiopathy may support early and correct identification. We aimed to identify and validate clinical- and cerebrospinal fluid-biomarkers for diagnosis of cerebral amyloid angiopathy. This observational cohort study screened 2795 consecutive patients admitted for cognitive complaints to the academic departments of neurology and psychiatry over a 10-year period (2009-2018).

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Article Synopsis
  • Alzheimer's disease (AD) is characterized by low levels of amyloid beta 42 (Aβ42) and high levels of phosphorylated Tau (pTau181) in cerebrospinal fluid, with cognitive decline being slower in individuals with just increased pTau181.
  • A new category called PASSED (nondemented subjects with increased pTau and Aβ surge) suggests some cognitive impairment without full AD symptoms, prompting research into their brain atrophy patterns.
  • This study analyzed the brain scans of non-demented individuals over time to see if those with different biomarker levels (A-T-N groups) showed distinct patterns of grey matter atrophy, finding no significant atrophy in the
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There is a paucity of empirical research on the use of non-pharmacological interventions to both treat and curb the spread of Alzheimer's disease (AD) across the globe. This paper examines the biochemical and clinical outlook and the social implications of the condition in relation to psychological aspects that may indicate a direction for further interventions. There is a scarcity of research on the effectiveness of using various psychological aspects of AD, a disease characterized by a process of transition from health and independence to a dependent state with a progressive loss of memory and functional skills.

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Introduction: Subjective cognitive decline (SCD) and depressive symptoms (DS) frequently co-occur prior to dementia. However, the temporal sequence of their emergence and their combined prognostic value for cognitive decline and dementia is unclear.

Methods: Temporal relationships of SCD, DS and memory decline were examined by latent difference score modeling in a high-aged, population-based cohort (N = 3217) and validated using Cox-regression of dementia-conversion.

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Article Synopsis
  • Amyloid-beta 42 (Aβ42) and phosphorylated tau (pTau) levels in cerebrospinal fluid (CSF) offer better insight into Alzheimer's disease (AD) than just clinical diagnosis.
  • The European Alzheimer & Dementia Biobank (EADB) analyzed data from 31 cohorts with over 13,000 individuals, identifying new genetic associations such as CR1 for Aβ42 and BIN1 for pTau, alongside novel associations with GMNC and C16orf95.
  • Analysis of all AD risk loci revealed four biological categories linked to Aβ42 and pTau, suggesting multiple pathways in AD's development, with further studies indicating GMNC and C16orf95 also relate to brain ventricular volume.
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Phosphorylated Tau181 (pTau181) in CSF and recently in plasma has been associated with Alzheimer's disease. In the absence of amyloidopathy, individuals with increased total Tau levels and/or temporal lobe atrophy experience no or only mild cognitive decline compared with biomarker-negative controls, leading to the proposal to categorize this constellation as suspected non-Alzheimer's disease pathophysiology (SNAP). We investigated whether the characteristics of SNAP also applied to individuals with increased CSF-pTau181 without amyloidopathy.

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Alzheimer's disease (AD) is a progressive condition and the most common cause of dementia worldwide. The neuropathological changes characteristic of the disorder can be successfully detected before the development of full-blown AD. Early diagnosis of the disease constitutes a formidable challenge for clinicians.

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Introduction: Elevated cortisol levels have been reported in Alzheimer's disease (AD) and may accelerate the development of brain pathology and cognitive decline. Dehydroepiandrosterone sulfate (DHEAS) has anti-glucocorticoid effects and it may be involved in the AD pathophysiology.

Objectives: To investigate associations of cerebrospinal fluid (CSF) cortisol and DHEAS levels with (1) cognitive performance at baseline; (2) CSF biomarkers of amyloid pathology (as assessed by CSF Aβ levels), neuronal injury (as assessed by CSF tau), and tau hyperphosphorylation (as assessed by CSF p-tau); (3) regional brain volumes; and (4) clinical disease progression.

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Background: Consideration of many tests from different cognitive domains in defining mild cognitive impairment (MCI) is clinical routine, but guidelines for a neuropsychological operationalization of MCI are lacking.

Objective: Among different operational MCI criteria, to identify those which are best in predicting either conversion to dementia, or a biomarker profile indicative for Alzheimer's disease (AD).

Methods: Memory clinic patients without dementia (N = 558; mean age = 66; up to 3 years of follow-up; n = 360 with baseline CSF biomarkers) were included in an observational study using most liberal criteria of cognitive impairment.

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Alzheimer's disease has a long asymptomatic phase that offers a substantial time window for intervention. Using this window of opportunity will require early diagnostic and prognostic biomarkers to detect Alzheimer's disease pathology at predementia stages, thus allowing identification of patients who will most probably progress to dementia of the Alzheimer's type and benefit from specific disease-modifying therapies. Consequently, we searched for CSF proteins associated with disease progression along with the clinical disease staging.

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ApoE4, the strongest genetic risk factor for Alzheimer's disease (AD), has been shown to be associated with both beta-amyloid (Aβ) and tau pathology, with the strongest evidence for effects on Aβ, while the association between ApoE4 and tau pathology remains inconsistent. This study aimed to investigate the associations between ApoE4 with CSF Aβ42, total tau (t-tau), phospho-tau181 (p-tau), and with the progression of decline in a large cohort of MCI subjects, both progressors to AD and other dementias, as well as non-progressors. We analyzed associations of CSF Aβ42, p-tau and t-tau with ApoE4 allele frequency cross-sectionally and longitudinally over 3 years of follow-up in 195 individuals with a diagnosis of MCI-stable, MCI-AD converters and MCI progressing to other dementias from the German Dementia Competence Network.

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Amyloid β 42/40 concentration quotient has been empirically shown to improve accuracy of the neurochemical diagnostics of Alzheimer's Disease (AD) compared to the Aβ42 concentration alone, but this improvement in diagnostic performance has not been backed up by a theoretical argumentation so far. In this report we show that better accuracy of Aβ42/40 compared to Aβ1-42 is granted by fundamental laws of probability. In particular, it can be shown that the dispersion of a distribution of a quotient of two random variables (Aβ42/40) is smaller than the dispersion of the random variable in the numerator (Aβ42), provided that the two variables are proportional.

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Article Synopsis
  • - The practice of measuring cerebrospinal fluid (CSF) biomarkers for diagnosing Alzheimer's disease (AD) is inconsistent across different medical centers, leading to varied interpretations of the same results.
  • - A study involving 40 centers worldwide analyzed their analytical protocols and reports to create a consensus on how to interpret CSF biomarker profiles effectively.
  • - The findings highlighted that while the analytical methods were largely similar, there was significant variability in how results were reported; as a result, harmonized reporting formats were established for clearer communication among laboratories.
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Background: Studies conducted so far have focused mainly on the assessment of IL-6 levels in patients with ruptured brain aneurysms. Carrying out detailed studies in patients with un-ruptured brain aneurysms (UIA) would be extremely important, as it would answer the question of whether IL-6 plays also a role in primary aneurysm formation and growth.

Methods: IL-6, S100, NSE, and albumin concentrations in 67 UIA patients and 17 individuals without vascular lesions in the brain were tested using in vitro diagnostic immunoassays according to the manufacturers' instructions.

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