| 1. |
- Hellwig, K., et al.
(författare)
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Neurogranin and YKL-40: independent markers of synaptic degeneration and neuroinflammation in Alzheimer's disease
- 2015
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Ingår i: Alzheimers Research & Therapy. - : Springer Science and Business Media LLC. - 1758-9193. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Neuroinflammation and synaptic degeneration are major neuropathological hallmarks in Alzheimer's disease (AD). Neurogranin and YKL-40 in cerebrospinal fluid (CSF) are newly discovered markers indicating synaptic damage and microglial activation, respectively. Methods: CSF samples from 95 individuals including 39 patients with AD dementia (AD-D), 13 with mild cognitive impairment (MCI) due to AD (MCI-AD), 29 with MCI not due to AD (MCI-o) and 14 patients with non-AD dementias (non-AD-D) were analyzed for neurogranin and YKL-40. Results: Patients with dementia or MCI due to AD showed elevated levels of CSF neurogranin (p < 0.001 for AD-D and p < 0.05 for MCI-AD) and YKL-40 (p < 0.05 for AD-D and p = 0.15 for MCI-AD) compared to mildly cognitively impaired subjects not diagnosed with AD. CSF levels of neurogranin and YKL-40 did not differ between MCI not due to AD and non-AD dementias. In AD subjects no correlation between YKL-40 and neurogranin was found. The CSF neurogranin levels correlated moderately with tau and p-tau but not with A beta 42 or the MMSE in AD samples. No relevant associations between YKL-40 and MMSE or the core AD biomarkers, A beta 42, t-tau and p-tau were found in AD subjects. Conclusions: Neurogranin and YKL-40 are promising AD biomarkers, independent of and complementary to the established core AD biomarkers, reflecting additional pathological changes in the course of AD.
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| 2. |
- Hölttä, Mikko, et al.
(författare)
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A single dose of the gamma-secretase inhibitor semagacestat alters the cerebrospinal fluid peptidome in humans
- 2016
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Ingår i: Alzheimers Research & Therapy. - : Springer Science and Business Media LLC. - 1758-9193. ; 8:11
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Tidskriftsartikel (refereegranskat)abstract
- Background: In Alzheimer's disease, beta-amyloid peptides in the brain aggregate into toxic oligomers and plaques, a process which is associated with neuronal degeneration, memory loss, and cognitive decline. One therapeutic strategy is to decrease the production of potentially toxic beta-amyloid species by the use of inhibitors or modulators of the enzymes that produce beta-amyloid from amyloid precursor protein (APP). The failures of several such drug candidates by lack of effect or undesired side-effects underscore the importance to monitor the drug effects in the brain on a molecular level. Here we evaluate if peptidomic analysis in cerebrospinal fluid (CSF) can be used for this purpose. Methods: Fifteen human healthy volunteers, divided into three groups, received a single dose of placebo or either 140 mg or 280 mg of the gamma-secretase inhibitor semagacestat (LY450139). Endogenous peptides in CSF, sampled prior to administration of the drug and at six subsequent time points, were analyzed by liquid chromatography coupled to mass spectrometry, using isobaric labeling based on the tandem mass tag approach for relative quantification. Results: Out of 302 reproducibly detected peptides, 11 were affected by the treatment. Among these, one was derived from APP and one from amyloid precursor-like protein 1. Nine peptides were derived from proteins that may not be gamma-secretase substrates per se, but that are regulated in a gamma-secretase-dependent manner. Conclusions: These results indicate that a CSF peptidomic approach may be a valuable tool both to verify target engagement and to identify other pharmacodynamic effects of the drug. Data are available via ProteomeXchange with identifier PXD003075.
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| 3. |
- Kvartsberg, Hlin, 1987, et al.
(författare)
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Characterization of the postsynaptic protein neurogranin in paired cerebrospinal fluid and plasma samples from Alzheimer's disease patients and healthy controls
- 2015
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Ingår i: Alzheimers Research & Therapy. - : Springer Science and Business Media LLC. - 1758-9193. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Synaptic dysfunction and degeneration are central events in Alzheimer's disease (AD) pathophysiology that are thought to occur early in disease progression. Synaptic pathology may be studied by examining protein biomarkers specific for different synaptic elements. We recently showed that the dendritic protein neurogranin (Ng), including the endogenous Ng peptide 48 to 76 (Ng(48-76)), is markedly increased in cerebrospinal fluid (CSF) in AD and that Ng48-76 is the dominant peptide in human brain tissue. The aim of this study was to characterize Ng in plasma and CSF using mass spectrometry and to investigate the performance of plasma Ng as an AD biomarker. Methods: Paired plasma and CSF samples from patients with AD (n = 25) and healthy controls (n = 20) were analyzed in parallel using an immunoassay developed in-house on the Meso Scale Discovery platform and hybrid immunoaffinity-mass spectrometry (HI-MS). A second plasma material from patients with AD (n = 13) and healthy controls (n = 17) was also analyzed with HI-MS. High-resolution mass spectrometry was used for identification of endogenous plasma Ng peptides. Results: Ng in human plasma is present as several endogenous peptides. Of the 16 endogenous Ng peptides identified, seven were unique for plasma and not detectable in CSF. However, Ng(48-76) was not present in plasma. CSF Ng was significantly increased in AD compared with controls (P < 0.0001), whereas the plasma Ng levels were similar between the groups in both studies. Plasma and CSF Ng levels showed no correlation. CSF Ng was stable during storage at -20 degrees C for up to 2 days, and no de novo generation of peptides were detected. Conclusions: For the first time, to our knowledge, we have identified several endogenous Ng peptides in human plasma. In agreement with previous studies, we show that CSF Ng is significantly increased in AD as compared with healthy controls. The origin of Ng in plasma and its possible use as a biomarker need to be further investigated. The results suggest that CSF Ng, in particular Ng(48-76), might reflect the neurodegenerative processes within the brain, indicating a role for Ng as a potential novel clinical biomarker for synaptic function in AD.
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| 4. |
- Minta, Karolina, et al.
(författare)
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Quantification of total apolipoprotein E and its isoforms in cerebrospinal fluid from patients with neurodegenerative diseases
- 2020
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Ingår i: Alzheimer's Research & Therapy. - : Springer Science and Business Media LLC. - 1758-9193. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Background The human APOE gene, which codes for apolipoprotein E (apoE), has three major polymorphic alleles: epsilon 2, epsilon 3, and epsilon 4 that give rise to amino acid substitutions. APOE-epsilon 4 is a strong risk factor of sporadic Alzheimer's disease (AD) but the reason why is still unknown despite intense research for more than 20 years. The aim of the study was to investigate if the concentrations of total apoE and the specific apoE isoforms in cerebrospinal fluid (CSF) differ between various neurodegenerative diseases and control individuals, as well as among the APOE genotypes. Methods Quantification of total apoE and specific apoE isoforms (E2, E3, and E4) in CSF was performed using high-resolution parallel reaction monitoring mass spectrometry. In total, 1820 individuals were involved in the study including clinically diagnosed AD patients (n = 228), cognitively unimpaired (CU) patients (n = 896), and patients with other neurodegenerative disorders (n = 696). Follow-up data was available for 100 individuals, assessed at two time points. Subjects were dichotomized based on an A beta(42/40) CSF concentration ratio cut-off into A beta positive (A beta+, < 0.091) and A beta negative (A beta-, > 0.091) groups. Results Even though there was a significant increase of total apoE in the amyloid beta-positive (A beta+) group compared with amyloid beta-negative (A beta-) individuals (p < 0.001), the magnitude of the effect was very small (AUC = 0.55). Moreover, CSF total apoE concentrations did not differ between A beta- CU controls and clinically diagnosed AD patients. There was a difference in concentration between isoforms in heterozygous individuals in an isoform-dependent manner (E2 < E3 < E4) (p < 0.001, AUC = 0.64-0.69), and these associations remained when dichotomizing the samples into A beta+ and A beta- groups (p < 0.01, AUC = 0.63-0.74). In the cohort with follow-up samples, neither total apoE nor isoform-specific apoE concentrations differed between the two time points (p > 0.05). Conclusions The results indicate that neither the concentrations of total apoE nor the different apoE isoforms in CSF are associated with APOE-epsilon 4 carrier status, A beta status, or clinical dementia diagnoses.
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| 5. |
- Obrocki, Pawel, et al.
(författare)
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Perspectives in fluid biomarkers in neurodegeneration from the 2019 biomarkers in neurodegenerative diseases course - A joint PhD student course at University College London and University of Gothenburg
- 2020
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Ingår i: Alzheimer's Research and Therapy. - : Springer Science and Business Media LLC. - 1758-9193. ; 12:1
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Forskningsöversikt (refereegranskat)abstract
- Until relatively recently, a diagnosis of probable Alzheimer's disease (AD) and other neurodegenerative disorders was principally based on clinical presentation, with post-mortem examination remaining a gold standard for disease confirmation. This is in sharp contrast to other areas of medicine, where fluid biomarkers, such as troponin levels in myocardial infarction, form an integral part of the diagnostic and treatment criteria. There is a pressing need for such quantifiable and easily accessible tools in neurodegenerative diseases. In this paper, based on lectures given at the 2019 Biomarkers in Neurodegenerative Diseases Course, we provide an overview of a range of cerebrospinal fluid (CSF) and blood biomarkers in neurodegenerative disorders, including the 'core' AD biomarkers amyloid β (Aβ) and tau, as well as other disease-specific and general markers of neuroaxonal injury. We then highlight the main challenges in the field, and how those could be overcome with the aid of new methodological advances, such as assay automation, mass spectrometry and ultrasensitive immunoassays. As we hopefully move towards an era of disease-modifying treatments, reliable biomarkers will be essential to increase diagnostic accuracy, allow for earlier diagnosis, better participant selection and disease activity and treatment effect monitoring.
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| 6. |
- Portelius, Erik, 1977, et al.
(författare)
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A novel Aβ isoform pattern in CSF reflects γ-secretase inhibition in Alzheimer disease
- 2010
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Ingår i: Alzheimer's research & therapy. - : Springer Science and Business Media LLC. - 1758-9193. ; 2:2
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT: INTRODUCTION: LY450139 (semagacestat) inhibits gamma-secretase, a key enzyme for generation of amyloid beta (Abeta), the peptide deposited in plaques in Alzheimer disease (AD). Previous data have shown that LY450139 lowers plasma Abeta, but has no clear effect on Abeta1-40 or Abeta1-42 levels in cerebrospinal fluid (CSF). By using targeted proteomics techniques, we recently identified several shorter Abeta isoforms, such as Abeta1-16, that in experimental settings increase during gamma-secretase inhibitor treatment, and thus may serve as sensitive biochemical indices of the treatment effect. Here, we test the hypothesis that these shorter Abeta isoforms may be biomarkers of gamma-secretase inhibitor treatment in clinical trials. METHODS: In a phase II clinical trial, 35 individuals with mild to moderate AD were randomized to placebo (n = 10) or LY450139 (100 mg (n = 15) or 140 mg (n = 10)) and underwent lumbar puncture at baseline and after 14 weeks of treatment. The CSF Abeta isoform pattern was analyzed with immunoprecipitation combined with MALDI-TOF mass spectrometry. RESULTS: The CSF levels of Abeta1-14, Abeta1-15, and Abeta1-16 showed a dose-dependent increase by 57% and 74%, 21% and 35%, and 30% and 67%, respectively in the 100-mg and 140-mg treatment groups. Abeta1-40 and Abeta1-42 were unaffected by treatment. CONCLUSIONS: CSF Abeta1-14, Abeta1-15, and Abeta1-16 increase during gamma-secretase inhibitor treatment in AD, even at doses that do not affect Abeta1-42 or Abeta1-40, probably because of increased substrate availability of the C99 APP stub (APP beta-CTF) induced by gamma-secretase inhibition. These Abeta isoforms may be novel sensitive biomarkers to monitor the biochemical effect in clinical trials. TRIAL REGISTRATION: Clinical Trials.gov NCT00244322.
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| 7. |
- Portelius, Erik, 1977, et al.
(författare)
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β-site amyloid precursor protein-cleaving enzyme 1(BACE1) inhibitor treatment induces Aβ5-X peptides through alternative amyloid precursor protein cleavage.
- 2014
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Ingår i: Alzheimer's research & therapy. - : Springer Science and Business Media LLC. - 1758-9193. ; 6:5-8
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Tidskriftsartikel (refereegranskat)abstract
- The β-secretase enzyme, β-site amyloid precursor protein-cleaving enzyme 1 (BACE1), cleaves amyloid precursor protein (APP) in the first step in β-amyloid (Aβ) peptide production. Thus, BACE1 is a key target for candidate disease-modifying treatment of Alzheimer's disease. In a previous exploratory Aβ biomarker study, we found that BACE1 inhibitor treatment resulted in decreased levels of Aβ1-34 together with increased Aβ5-40, suggesting that these Aβ species may be novel pharmacodynamic biomarkers in clinical trials. We have now examined whether the same holds true in humans.
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| 8. |
- Sjödin, Simon, et al.
(författare)
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APLP1 as a cerebrospinal fluid biomarker for gamma-secretase modulator treatment
- 2015
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Ingår i: Alzheimers Research & Therapy. - : Springer Science and Business Media LLC. - 1758-9193. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Alzheimer's disease brains are characterized by extracellular plaques containing the aggregated amyloid beta(42) (A beta(42)) peptide and intraneuronal tangles containing hyperphosphorylated tau. A beta(42) is produced by sequential processing of the amyloid precursor protein (APP) by beta-secretase followed by gamma-secretase. Substantial efforts have been put into developing pharmaceuticals preventing the production or increasing the clearance of A beta(42). However, treatments inhibiting gamma- secretase have proven disappointing due to off-target effects. To circumvent these effects, gamma-secretase modulators (GSMs) have been developed, which rather than inhibiting gamma- secretase shift its preference into producing less aggregation-prone shorter A beta peptides. Belonging to the same family of proteins as APP, amyloid-like protein 1 (APLP1) is also a substrate for gamma-secretase. Herein we investigated whether the GSM E2012 affects APLP1 processing in the central nervous system by measuring APLP1 peptide levels in cerebrospinal fluid (CSF) before and after E2012 treatment in dogs. Methods: An in-house monoclonal APLP1 antibody, AP1, was produced and utilized for immunopurification of APLP1 from human and dog CSF in a hybrid immuno-affinity mass spectrometric method. Seven dogs received a single dose of 20 or 80 mg/kg of E2012 in a randomized cross-over design and CSF was collected prior to and 4, 8 and 24 hours after dosing. Results: We have identified 14 CSF APLP1 peptides in humans and 12 CSF APLP1 peptides in dogs. Of these, seven were reproducibly detectable in dogs who received E2012. We found a dose-dependent relative increase of the CSF peptides APLP1 beta 17, 1 beta 18 and 1 beta 28 accompanied with a decrease of 1 beta 25 and 1 beta 27 in response to E2012 treatment. All peptides reverted to baseline over the time of sample collection. Conclusion: We show an in vivo effect of the GSM E2012 on the processing of APLP1 which is measurable in CSF. These data suggest that APLP1 peptides may be used as biomarkers to monitor drug effects of GSMs on gamma-secretase processing in clinical trials. However, this requires further investigation in larger cohorts, including studies in man.
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| 9. |
- Valur Dansson, Hákon, 1993, et al.
(författare)
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Predicting progression and cognitive decline in amyloid-positive patients with Alzheimer's disease
- 2021
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Ingår i: Alzheimers Research & Therapy. - : Springer Science and Business Media LLC. - 1758-9193. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Background In Alzheimer's disease, amyloid- beta (A beta) peptides aggregate in the lowering CSF amyloid levels - a key pathological hallmark of the disease. However, lowered CSF amyloid levels may also be present in cognitively unimpaired elderly individuals. Therefore, it is of great value to explain the variance in disease progression among patients with A beta pathology. Methods A cohort of n=2293 participants, of whom n=749 were A beta positive, was selected from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database to study heterogeneity in disease progression for individuals with A beta pathology. The analysis used baseline clinical variables including demographics, genetic markers, and neuropsychological data to predict how the cognitive ability and AD diagnosis of subjects progressed using statistical models and machine learning. Due to the relatively low prevalence of A beta pathology, models fit only to A beta-positive subjects were compared to models fit to an extended cohort including subjects without established A beta pathology, adjusting for covariate differences between the cohorts. Results A beta pathology status was determined based on the A beta(42)/A beta(40) ratio. The best predictive model of change in cognitive test scores for A beta-positive subjects at the 2-year follow-up achieved an R-2 score of 0.388 while the best model predicting adverse changes in diagnosis achieved a weighted F-1 score of 0.791. A beta-positive subjects declined faster on average than those without A beta pathology, but the specific level of CSF A beta was not predictive of progression rate. When predicting cognitive score change 4 years after baseline, the best model achieved an R-2 score of 0.325 and it was found that fitting models to the extended cohort improved performance. Moreover, using all clinical variables outperformed the best model based only on a suite of cognitive test scores which achieved an R-2 score of 0.228. Conclusion Our analysis shows that CSF levels of A beta are not strong predictors of the rate of cognitive decline in A beta-positive subjects when adjusting for other variables. Baseline assessments of cognitive function accounts for the majority of variance explained in the prediction of 2-year decline but is insufficient for achieving optimal results in longer-term predictions. Predicting changes both in cognitive test scores and in diagnosis provides multiple perspectives of the progression of potential AD subjects.
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