| 1. |
- Almkvist, Ove, et al.
(författare)
-
A biomarker-validated time scale in years of disease progression has identified early- and late-onset subgroups in sporadic Alzheimer's disease
- 2023
-
Ingår i: Alzheimer's Research & Therapy. - : Springer Nature. - 1758-9193. ; 15:1
-
Tidskriftsartikel (refereegranskat)abstract
- Background: It is possible to calculate the number of years to the expected clinical onset (YECO) of autosomal-dominant Alzheimer's disease (adAD). A similar time scale is lacking for sporadic Alzheimer's disease (sAD). The purpose was to design and validate a time scale in YECO for patients with sAD in relation to CSF and PET biomarkers. Methods: Patients diagnosed with Alzheimer's disease (AD, n = 48) or mild cognitive impairment (MCI, n = 46) participated in the study. They underwent a standardized clinical examination at the Memory clinic, Karolinska University Hospital, Stockholm, Sweden, which included present and previous medical history, laboratory screening, cognitive assessment, CSF biomarkers (A beta(42), total-tau, and p-tau), and an MRI of the brain. They were also assessed with two PET tracers, C-11-Pittsburgh compound B and F-18-fluorodeoxyglucose. Assuming concordance of cognitive decline in sAD and adAD, YECO for these patients was calculated using equations for the relationship between cognitive performance, YECO, and years of education in adAD (Almkvist et al. J Int Neuropsychol Soc 23:195-203, 2017). Results: The mean current point of disease progression was 3.2 years after the estimated clinical onset in patients with sAD and 3.4 years prior to the estimated clinical onset in patients with MCI, as indicated by the median YECO from five cognitive tests. The associations between YECO and biomarkers were significant, while those between chronological age and biomarkers were nonsignificant. The estimated disease onset (chronological age minus YECO) followed a bimodal distribution with frequency maxima before (early-onset) and after (late-onset) 65 years of age. The early- and late-onset subgroups differed significantly in biomarkers and cognition, but after control for YECO, this difference disappeared for all except the APOE e4 gene (more frequent in early- than in late-onset). Conclusions: A novel time scale in years of disease progression based on cognition was designed and validated in patients with AD using CSF and PET biomarkers. Two early- and late-disease onset subgroups were identified differing with respect to APOE e4.
|
|
| 2. |
- Saint-Aubert, Laure, et al.
(författare)
-
Regional tau deposition measured by [F-18]THK5317 positron emission tomography is associated to cognition via glucose metabolism in Alzheimer's disease
- 2016
-
Ingår i: Alzheimer's Research & Therapy. - : Springer Science and Business Media LLC. - 1758-9193. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The recent development of tau-specific positron emission tomography (PET) tracers has allowed in vivo quantification of regional tau deposition and offers the opportunity to monitor the progression of tau pathology along with cognitive impairment. In this study, we investigated the relationships of cerebral tau deposition ([F-18]THK5317-PET) and metabolism ([F-18]FDG-PET) with concomitant cognitive function in patients with probable Alzheimer's disease (AD). Methods: Nine patients diagnosed with AD dementia and 11 with prodromal AD (mild cognitive impairment, amyloid-positive on [C-11]PiB-PET) were included in this study. All patients underwent PET scans using each tracer, as well as episodic memory and global cognition assessment. Linear models were used to investigate the association of regional [F-18]THK5317 retention and [F-18]FDG uptake with cognition. The possible mediating effect of local metabolism on the relationship between tau deposition and cognitive performance was investigated using mediation analyses. Results: Significant negative associations were found between [F-18]THK5317 regional retention, mainly in temporal regions, and both episodic memory and global cognition. Significant positive associations were found between [F-18]FDG regional uptake and cognition. The association of [F-18]FDG with global cognition was regionally more extensive than that of [F-18]THK5317, while the opposite was observed with episodic memory, suggesting that [F-18]THK5317 retention might be more sensitive than [F-18]FDG regional uptake to early cognitive impairment. Finally, [F-18]FDG uptake had a mediating effect on the relationship between [F-18]THK5317 retention in temporal regions and global cognition. Conclusions: These findings suggest a mediating role for local glucose metabolism in the observed association between in vivo tau deposition and concomitant cognitive impairment in AD.
|
|
| 3. |
- Thordardottir, Steinunn, et al.
(författare)
-
Reduced penetrance of the PSEN1 H163Y autosomal dominant Alzheimer mutation : A 22-year follow-up study
- 2018
-
Ingår i: Alzheimer's Research & Therapy. - : Springer Science and Business Media LLC. - 1758-9193. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The range of onset ages within some PSEN1 families is wide, and a few cases of reduced penetrance of PSEN1 mutations have been reported. However, published data on reduced penetrance have been limited to clinical histories, often collected retrospectively and lacking biomarker information. We present a case of reduced penetrance of the PSEN1 H163Y mutation in a carrier prospectively followed for 22 years. Methods: Two brothers (A and B), both carriers of the H163Y mutation, were followed between 1995 and 2017. They underwent repeated clinical evaluations, neuropsychological assessments, and cerebrospinal fluid analyses, as well as brain imaging examinations with structural magnetic resonance, [F-18] fluorodeoxyglucose positron emission tomography, and [C-11] Pittsburgh compound B positron emission tomography. Results: Brother A was followed between 44 and 64 years of age. Cognitive symptoms due to Alzheimer's disease set in at the age of 54. Gradual worsening of symptoms resulted in admittance to a nursing home owing to dependence on others for all activities of daily living. He showed a curvilinear decline in cognitive function on neuropsychological tests, and changes on magnetic resonance imaging, positron emission tomography, and biomarkers in the cerebrospinal fluid supported a clinical diagnosis of Alzheimer's disease. Brother A died at the age of 64 and fulfilled the criteria for definitive Alzheimer's disease according to neuropathological examination results. Brother B was followed between the ages of 43 and 65 and showed no cognitive deterioration on repeated neuropsychological test occasions. In addition, no biomarker evidence of Alzheimer's disease pathology was detected, either on imaging examinations or in cerebrospinal fluid. Conclusions: The average (SD) age of symptom onset for PSEN1 H163Y is 51 +/- 7 years according to previous studies. However, we present a case of a biomarker-verified reduction in penetrance in a mutation carrier who was still symptom-free at the age of 65. This suggests that other genetic, epigenetic, and/or environmental factors modify the onset age.
|
|
