| 1. |
- Mattsson, Niklas, 1979, et al.
(författare)
-
BACE1 inhibition induces a specific cerebrospinal fluid β-amyloid pattern that identifies drug effects in the central nervous system.
- 2012
-
Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 7:2
-
Tidskriftsartikel (refereegranskat)abstract
- BACE1 is a key enzyme for amyloid-β (Aβ) production, and an attractive therapeutic target in Alzheimer's disease (AD). Here we report that BACE1 inhibitors have distinct effects on neuronal Aβ metabolism, inducing a unique pattern of secreted Aβ peptides, analyzed in cell media from amyloid precursor protein (APP) transfected cells and in cerebrospinal fluid (CSF) from dogs by immunoprecipitation-mass spectrometry, using several different BACE1 inhibitors. Besides the expected reductions in Aβ1-40 and Aβ1-42, treatment also changed the relative levels of several other Aβ isoforms. In particular Aβ1-34 decreased, while Aβ5-40 increased, and these changes were more sensitive to BACE1 inhibition than the changes in Aβ1-40 and Aβ1-42. The effects on Aβ5-40 indicate the presence of a BACE1 independent pathway of APP degradation. The described CSF Aβ pattern may be used as a pharmacodynamic fingerprint to detect biochemical effects of BACE1-therapies in clinical trials, which might accelerate development of novel therapies.
|
|
| 2. |
- Parnetti, L, et al.
(författare)
-
Changes in CSF acetyl- and butyrylcholinesterase activity after long-term treatment with AChE inhibitors in Alzheimer's disease.
- 2011
-
Ingår i: Acta neurologica Scandinavica. - : Hindawi Limited. - 1600-0404 .- 0001-6314. ; 124:2, s. 122-129
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives - To measure cerebrospinal fluid (CSF) activity of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) in patients with Alzheimer's disease (AD) participating in randomized clinical trials from three European centers, before and after long-term treatment with different AChE inhibitors (AChEIs). Materials and methods - Of the 144 patients included in the study, 104 were treated with donepezil, 15 with galantamine, 16 with rivastigmine, and nine with placebo. CSF AChE and BChE activities were measured at baseline and after 1- year treatment. Results - Donepezil and galantamine groups showed a significant increase in CSF AChE activity at follow-up, while no changes for BChE activity were observed; in donepezil group, a positive correlation between plasma concentration and AChE activity was documented. Conversely, in rivastigmine group, a decrease in CSF activity of both enzymes was observed. CSF AChE and BChE activities were not correlated with the clinical outcome in any group considered. CSF biomarkers did not show any change after treatment. Conclusions - AChEIs differently influence the activity of target enzymes in CSF independent of their pharmacodynamic effects.
|
|
| 3. |
- Westwood, Sarah, et al.
(författare)
-
The influence of insulin resistance on cerebrospinal fluid and plasma biomarkers of Alzheimer's pathology.
- 2017
-
Ingår i: Alzheimer's research & therapy. - : Springer Science and Business Media LLC. - 1758-9193. ; 9:1
-
Tidskriftsartikel (refereegranskat)abstract
- Insulin resistance (IR) has previously been associated with an increased risk of developing Alzheimer's disease (AD), although the relationship between IR and AD is not yet clear. Here, we examined the influence of IR on AD using plasma and cerebrospinal fluid (CSF) biomarkers related to IR and AD in cognitively healthy men. We also aimed to characterise the shared protein signatures between IR and AD.Fifty-eight cognitively healthy men, 28 IR and 30 non-IR (age and APOE ε4 matched), were drawn from the Metabolic Syndrome in Men study in Kuopio, Finland. CSF AD biomarkers (amyloid β-peptide (Aβ), total tau and tau phosphorylated at the Thr181 epitope) were examined with respect to IR. Targeted proteomics using ELISA and Luminex xMAP assays were performed to assess the influence of IR on previously identified CSF and plasma protein biomarker candidates of AD pathology. Furthermore, CSF and plasma SOMAscan was performed to discover proteins that associate with IR and CSF AD biomarkers.CSF AD biomarkers did not differ between IR and non-IR groups, although plasma insulin correlated with CSF Aβ/tau across the whole cohort. In total, 200 CSF and 487 plasma proteins were differentially expressed between IR and non-IR subjects, and significantly enriched pathways, many of which have been previously implicated in AD, were identified. CSF and plasma proteins significantly associated with CSF AD biomarkers were also discovered, and those sensitive to both IR and AD were identified.These data indicate that IR is not directly related to the level of CSF AD pathology in cognitively healthy men. Proteins that associated with both AD and IR are potential markers indicative of shared pathology.
|
|
| 4. |
- Alifier, Marek, et al.
(författare)
-
Cardiac Surgery is Associated with Biomarker Evidence of Neuronal Damage.
- 2020
-
Ingår i: Journal of Alzheimer's disease : JAD. - 1875-8908. ; 74:4, s. 1211-1220
-
Tidskriftsartikel (refereegranskat)abstract
- Anesthesia and surgery is commonly associated with central nervous system sequelae and cognitive symptoms, which may be caused by neuronal injury. Neuronal injury can be monitored by plasma concentrations of the neuronal biomarkers tau and neurofilament light protein (NFL). Currently, there are no studies examining whether neuronal injury varies between surgical procedures.Our aim was to investigate if neuronal damage is more frequent after cardiac than after otolaryngeal surgery, as estimated by tau and NFL concentrations in plasma.Blood samples were drawn before, during, and after surgery and concentrations of tau, NFL, Aβ40, and Aβ42 were measured in 25 patients undergoing cardiac surgery (9 off-pump and 16 on-pump) and 26 patients undergoing otolaryngeal surgery.Tau increased during surgery (1752%, p = 0.0001) and NFL rose seven days post-surgery (1090%, p < 0.0001) in patients undergoing cardiac surgery; even more in patients on-pump than off-pump. No changes were observed in patients undergoing otolaryngeal surgery and only minor fluctuations were observed for Aβ40 and Aβ42.Cardiac surgery is associated with neuronal injury, which is aggravated by extracorporeal circulation. Analyses of NFL and tau in blood may guide development of surgical procedures to minimize neuronal damage, and may also be used in longitudinal clinical studies to assess the relationship of surgery with future neurocognitive impairment or dementia.
|
|
| 5. |
- Alves, Guido, et al.
(författare)
-
Cerebrospinal fluid amyloid-β and phenotypic heterogeneity in de novo Parkinson's disease.
- 2013
-
Ingår i: Journal of neurology, neurosurgery, and psychiatry. - : BMJ. - 1468-330X .- 0022-3050. ; 84:5, s. 537-43
-
Tidskriftsartikel (refereegranskat)abstract
- In Parkinson's disease (PD), the motor presentation characterised by postural instability/gait difficulties (PIGD) heralds accelerated motor, functional and cognitive decline, as compared with the more benign tremor-dominant (TD) variant. This makes the PIGD complex an attractive target for the discovery of prognostic biomarkers in PD.
|
|
| 6. |
- Alves, G., et al.
(författare)
-
CSF A beta(42) predicts early-onset dementia in Parkinson disease
- 2014
-
Ingår i: Neurology. - : Ovid Technologies (Wolters Kluwer Health). - 0028-3878 .- 1526-632X. ; 82:20, s. 1784-1790
-
Tidskriftsartikel (refereegranskat)abstract
- Objective:To test in vivo the proposal from clinicopathologic studies that -amyloid (A) pathology shortens the time to dementia in Parkinson disease (PD), and to explore the utility of CSF A and related measures as early prognostic biomarkers of dementia in an incident PD cohort.Methods:We assessed a population-based incident cohort of 104 patients with PD who underwent lumbar puncture at diagnosis. We analyzed CSF concentrations of A42, A40, and A38 using a multiplexed immunoassay with electrochemiluminescence (ECL) detection and levels of A42, total tau, and phosphorylated tau using ELISA. Patients were followed prospectively for 5 years. Dementia was diagnosed according to published criteria.Results:CSF levels of A42 were significantly decreased in patients who developed dementia (n = 20, 19.2%) compared to those who did not (n = 84, 80.8%), as measured by ECL (-33%, p = 0.006) as well as ELISA (-36%, p < 0.001). No differences were observed for other markers. Low A42 values predicted a substantially increased risk for subsequent dementia at high sensitivity (85%), with hazard ratios of 9.9 (95% confidence interval 2.3-43.5, p = 0.002) for A42(ECL) <376 pg/mL and 7.6 (2.2-26.4, p = 0.001) for A42(ELISA) <443 pg/mL, after adjustment for baseline age and PD-mild cognitive impairment (MCI) status. A42 reductions tended to precede the onset of PD-MCI that progressed to dementia.Conclusions:These in vivo data support the role of A pathology in the etiology and highlight the potential utility of CSF A42 as an early prognostic biomarker of dementia associated with PD.
|
|
| 7. |
- Alves, Guido, et al.
(författare)
-
CSF amyloid-β and tau proteins, and cognitive performance, in early and untreated Parkinson's Disease: the Norwegian ParkWest study
- 2010
-
Ingår i: Journal of neurology, neurosurgery, and psychiatry. - : BMJ. - 1468-330X .- 0022-3050. ; 81:10, s. 1080-1086
-
Tidskriftsartikel (refereegranskat)abstract
- Background Alzheimer's disease (AD) pathology is found in a considerable portion of patients with Parkinson's disease (PD), particularly those with early dementia (PDD). Altered cerebrospinal fluid (CSF) levels of amyloid-beta (Abeta) and tau proteins have been found in PDD, with intermediate changes for Abeta42 in non-demented PD. The authors investigated whether AD-related CSF protein levels are altered and relate to neuropsychological performance in early, untreated PD. Methods CSF concentrations of Abeta42, Abeta40 and Abeta38 were measured by electrochemiluminiscene and levels of total tau (T-tau) and phosphorylated tau (P-tau) by ELISA in 109 newly diagnosed, unmedicated, non-demented, community-based PD patients who had undergone comprehensive neuropsychological testing, and were compared with those of 36 age-matched normal controls and 20 subjects with mild AD. Results PD patients displayed significant reductions in Abeta42 (19%; p=0.009), Abeta40 (15.5%; p=0.008) and Abeta38 (23%; p=0.004) but not T-tau (p=0.816) or P-tau (p=0.531) compared with controls. CSF Abeta42 reductions in PD were less marked than in AD (53%; p=0.002). Sequential regression analyses demonstrated significant associations between CSF levels of Abeta42 (beta=0.205; p=0.019), Abeta40 (beta=0.378; p<0.001) and Abeta38 (beta=0.288; p=0.001) and memory impairment, but not executive-attentional or visuospatial dysfunction. Tau protein levels did not correlate with cognitive measures. Conclusion CSF Abeta levels are altered in a subset of patients with early PD and relate to memory impairment. Our study suggests that alterations in Abeta protein metabolism may contribute to the heterogeneity in pattern and course of cognitive decline associated with PD. Longitudinal studies are needed to clarify the clinical significance of CSF Abeta peptides as prognostic biomarkers in PD.
|
|
| 8. |
- Alves, Guido, et al.
(författare)
-
CSF Aβ42 predicts early-onset dementia in Parkinson disease.
- 2014
-
Ingår i: Neurology. - 1526-632X. ; 82:20, s. 1784-90
-
Tidskriftsartikel (refereegranskat)abstract
- To test in vivo the proposal from clinicopathologic studies that β-amyloid (Aβ) pathology shortens the time to dementia in Parkinson disease (PD), and to explore the utility of CSF Aβ and related measures as early prognostic biomarkers of dementia in an incident PD cohort.
|
|
| 9. |
- Andreasson, Ulf, 1968, et al.
(författare)
-
A Practical Guide to Immunoassay Method Validation.
- 2015
-
Ingår i: Frontiers in neurology. - : Frontiers Media SA. - 1664-2295. ; 6
-
Tidskriftsartikel (refereegranskat)abstract
- Biochemical markers have a central position in the diagnosis and management of patients in clinical medicine, and also in clinical research and drug development, also for brain disorders, such as Alzheimer's disease. The enzyme-linked immunosorbent assay (ELISA) is frequently used for measurement of low-abundance biomarkers. However, the quality of ELISA methods varies, which may introduce both systematic and random errors. This urges the need for more rigorous control of assay performance, regardless of its use in a research setting, in clinical routine, or drug development. The aim of a method validation is to present objective evidence that a method fulfills the requirements for its intended use. Although much has been published on which parameters to investigate in a method validation, less is available on a detailed level on how to perform the corresponding experiments. To remedy this, standard operating procedures (SOPs) with step-by-step instructions for a number of different validation parameters is included in the present work together with a validation report template, which allow for a well-ordered presentation of the results. Even though the SOPs were developed with the intended use for immunochemical methods and to be used for multicenter evaluations, most of them are generic and can be used for other technologies as well.
|
|
| 10. |
- Andreasson, Ulf, 1968, et al.
(författare)
-
Assessing the commutability of candidate reference materials for the harmonization of neurofilament light measurements in blood
- 2023
-
Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter GmbH. - 1434-6621 .- 1437-4331. ; 61:7, s. 1245-1254
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives Neurofilament light chain (NfL) concentration in blood is a biomarker of neuro-axonal injury in the nervous system and there now exist several assays with high enough sensitivity to measure NfL in serum and plasma. There is a need for harmonization with the goal of creating a certified reference material (CRM) for NfL and an early step in such an effort is to determine the best matrix for the CRM. This is done in a commutability study and here the results of the first one for NfL in blood is presented.Methods Forty paired individual serum and plasma samples were analyzed for NfL on four different analytical platforms. Neat and differently spiked serum and plasma were evaluated for their suitability as a CRM using the difference in bias approach.Results The correlation between the different platforms with regards to measured NfL concentrations were very high (Spearman's rho >= 0.96). Samples spiked with cerebrospinal fluid (CSF) showed higher commutability compared to samples spiked with recombinant human NfL protein and serum seems to be a better choice than plasma as the matrix for a CRM.Conclusions The results from this first commutability study on NfL in serum/plasma showed that it is feasible to create a CRM for NfL in blood and that spiking should be done using CSF rather than with recombinant human NfL protein.
|
|
