| 1. |
- Sliz, E., et al.
(författare)
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Evidence of a causal effect of genetic tendency to gain muscle mass on uterine leiomyomata
- 2023
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Uterine leiomyomata (UL) are the most common tumours of the female genital tract and the primary cause of surgical removal of the uterus. Genetic factors contribute to UL susceptibility. To add understanding to the heritable genetic risk factors, we conduct a genome-wide association study (GWAS) of UL in up to 426,558 European women from FinnGen and a previous UL meta-GWAS. In addition to the 50 known UL loci, we identify 22 loci that have not been associated with UL in prior studies. UL-associated loci harbour genes enriched for development, growth, and cellular senescence. Of particular interest are the smooth muscle cell differentiation and proliferation-regulating genes functioning on the myocardin-cyclin dependent kinase inhibitor 1A pathway. Our results further suggest that genetic predisposition to increased fat-free mass may be causally related to higher UL risk, underscoring the involvement of altered muscle tissue biology in UL pathophysiology. Overall, our findings add to the understanding of the genetic pathways underlying UL, which may aid in developing novel therapeutics.
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| 2. |
- Tabassum, R, et al.
(författare)
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Genetic architecture of human plasma lipidome and its link to cardiovascular disease
- 2019
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Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10:1, s. 4329-
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Tidskriftsartikel (refereegranskat)abstract
- Understanding genetic architecture of plasma lipidome could provide better insights into lipid metabolism and its link to cardiovascular diseases (CVDs). Here, we perform genome-wide association analyses of 141 lipid species (n = 2,181 individuals), followed by phenome-wide scans with 25 CVD related phenotypes (n = 511,700 individuals). We identify 35 lipid-species-associated loci (P <5 ×10−8), 10 of which associate with CVD risk including five new loci-COL5A1, GLTPD2, SPTLC3, MBOAT7 and GALNT16 (false discovery rate<0.05). We identify loci for lipid species that are shown to predict CVD e.g., SPTLC3 for CER(d18:1/24:1). We show that lipoprotein lipase (LPL) may more efficiently hydrolyze medium length triacylglycerides (TAGs) than others. Polyunsaturated lipids have highest heritability and genetic correlations, suggesting considerable genetic regulation at fatty acids levels. We find low genetic correlations between traditional lipids and lipid species. Our results show that lipidomic profiles capture information beyond traditional lipids and identify genetic variants modifying lipid levels and risk of CVD.
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| 3. |
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| 4. |
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| 5. |
- Jansen, Willemijn J, et al.
(författare)
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Prevalence Estimates of Amyloid Abnormality Across the Alzheimer Disease Clinical Spectrum.
- 2022
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Ingår i: JAMA neurology. - : American Medical Association (AMA). - 2168-6157 .- 2168-6149. ; 79:3, s. 228-243
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Tidskriftsartikel (refereegranskat)abstract
- One characteristic histopathological event in Alzheimer disease (AD) is cerebral amyloid aggregation, which can be detected by biomarkers in cerebrospinal fluid (CSF) and on positron emission tomography (PET) scans. Prevalence estimates of amyloid pathology are important for health care planning and clinical trial design.To estimate the prevalence of amyloid abnormality in persons with normal cognition, subjective cognitive decline, mild cognitive impairment, or clinical AD dementia and to examine the potential implications of cutoff methods, biomarker modality (CSF or PET), age, sex, APOE genotype, educational level, geographical region, and dementia severity for these estimates.This cross-sectional, individual-participant pooled study included participants from 85 Amyloid Biomarker Study cohorts. Data collection was performed from January 1, 2013, to December 31, 2020. Participants had normal cognition, subjective cognitive decline, mild cognitive impairment, or clinical AD dementia. Normal cognition and subjective cognitive decline were defined by normal scores on cognitive tests, with the presence of cognitive complaints defining subjective cognitive decline. Mild cognitive impairment and clinical AD dementia were diagnosed according to published criteria.Alzheimer disease biomarkers detected on PET or in CSF.Amyloid measurements were dichotomized as normal or abnormal using cohort-provided cutoffs for CSF or PET or by visual reading for PET. Adjusted data-driven cutoffs for abnormal amyloid were calculated using gaussian mixture modeling. Prevalence of amyloid abnormality was estimated according to age, sex, cognitive status, biomarker modality, APOE carrier status, educational level, geographical location, and dementia severity using generalized estimating equations.Among the 19097 participants (mean [SD] age, 69.1 [9.8] years; 10148 women [53.1%]) included, 10139 (53.1%) underwent an amyloid PET scan and 8958 (46.9%) had an amyloid CSF measurement. Using cohort-provided cutoffs, amyloid abnormality prevalences were similar to 2015 estimates for individuals without dementia and were similar across PET- and CSF-based estimates (24%; 95% CI, 21%-28%) in participants with normal cognition, 27% (95% CI, 21%-33%) in participants with subjective cognitive decline, and 51% (95% CI, 46%-56%) in participants with mild cognitive impairment, whereas for clinical AD dementia the estimates were higher for PET than CSF (87% vs 79%; mean difference, 8%; 95% CI, 0%-16%; P=.04). Gaussian mixture modeling-based cutoffs for amyloid measures on PET scans were similar to cohort-provided cutoffs and were not adjusted. Adjusted CSF cutoffs resulted in a 10% higher amyloid abnormality prevalence than PET-based estimates in persons with normal cognition (mean difference, 9%; 95% CI, 3%-15%; P=.004), subjective cognitive decline (9%; 95% CI, 3%-15%; P=.005), and mild cognitive impairment (10%; 95% CI, 3%-17%; P=.004), whereas the estimates were comparable in persons with clinical AD dementia (mean difference, 4%; 95% CI, -2% to 9%; P=.18).This study found that CSF-based estimates using adjusted data-driven cutoffs were up to 10% higher than PET-based estimates in people without dementia, whereas the results were similar among people with dementia. This finding suggests that preclinical and prodromal AD may be more prevalent than previously estimated, which has important implications for clinical trial recruitment strategies and health care planning policies.
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| 6. |
- Leinonen, V, et al.
(författare)
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Positron emission tomography with [18F]flutemetamol and [11C]PiB for in vivo detection of cerebral cortical amyloid in normal pressure hydrocephalus patients.
- 2013
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Ingår i: European Journal of Neurology. - : Wiley. - 1351-5101 .- 1468-1331. ; 20:7, s. 1043-52
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE: This study determined the correlation between uptake of the amyloid positron emission tomography (PET) imaging agent [(18) F]flutemetamol and amyloid-β measured by immunohistochemical and histochemical staining in a frontal cortical biopsy.METHODS: Fifteen patients with possible normal pressure hydrocephalus (NPH) and previous brain biopsy obtained during intracranial pressure monitoring underwent [18F]flutemetamol PET. Seven of these patients also underwent [11C] Pittsburgh compound B (PiB) PET. [18F]Flutemetamol and [11C]PiB uptake was quantified using standardized uptake value ratio (SUVR) with the cerebellar cortex as a reference region. Tissue amyloid-β was evaluated using the monoclonal antibody 4G8, Thioflavin-S and Bielschowsky silver stain.RESULTS: [18F]Flutemetamol and [11C]PiB SUVRs correlated with biopsy specimen amyloid-β levels contralateral (r = 0.86, P < 0.0001; r = 0.96, P = 0.0008) and ipsilateral (r = 0.82, P = 0.0002; r = 0.87, P = 0.01) to the biopsy site. Association between cortical composite [(18) F]flutemetamol SUVRs and [11C]PiB SUVRs was highly significant (r = 0.97, P = 0.0003).CONCLUSIONS: [18F]Flutemetamol detects brain amyloid-β in vivo with moderate to high sensitivity and high specificity. This agent, therefore, represents a valuable new tool to study and verify the presence of amyloid-β pathology, both in patients with possible NPH and among the wider population.
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| 7. |
- Mattsson, Niklas, et al.
(författare)
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Prevalence of the apolipoprotein E epsilon 4 allele in amyloid beta positive subjects across the spectrum of Alzheimers disease
- 2018
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Ingår i: Alzheimer's & Dementia. - : ELSEVIER SCIENCE INC. - 1552-5260 .- 1552-5279. ; 14:7, s. 913-924
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Apolipoprotein E (APOE) epsilon 4 is the major genetic risk factor for Alzheimers disease (AD), but its prevalence is unclear because earlier studies did not require biomarker evidence of amyloid beta(A beta) pathology. Methods: We included 3451 A beta+ subjects (853 AD-type dementia, 1810 mild cognitive impairment, and 788 cognitively normal). Generalized estimating equation models were used to assess APOE epsilon 4 prevalence in relation to age, sex, education, and geographical location. Results: The APOE epsilon 4 prevalence was 66% in AD-type dementia, 64% in mild cognitive impairment, and 51% in cognitively normal, and it decreased with advancing age in A beta+ cognitively normal and A beta+ mild cognitive impairment (P amp;lt;.05) but not in A beta+ AD dementia (P =.66). The prevalence was highest in Northern Europe but did not vary by sex or education. Discussion: The APOE E4 prevalence in AD was higher than that in previous studies, which did not require presence of A beta pathology. Furthermore, our results highlight disease heterogeneity related to age and geographical location. (C) 2018 the Alzheimers Association. Published by Elsevier Inc. All rights reserved.
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| 8. |
- Mattsson, Niklas, et al.
(författare)
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Prevalence of the apolipoprotein E ε4 allele in amyloid β positive subjects across the spectrum of Alzheimer's disease
- 2018
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Ingår i: Alzheimer's and Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 14:7, s. 913-924
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Apolipoprotein E (APOE) ε4 is the major genetic risk factor for Alzheimer's disease (AD), but its prevalence is unclear because earlier studies did not require biomarker evidence of amyloid β (Aβ) pathology. Methods: We included 3451 Aβ+ subjects (853 AD-type dementia, 1810 mild cognitive impairment, and 788 cognitively normal). Generalized estimating equation models were used to assess APOE ε4 prevalence in relation to age, sex, education, and geographical location. Results: The APOE ε4 prevalence was 66% in AD-type dementia, 64% in mild cognitive impairment, and 51% in cognitively normal, and it decreased with advancing age in Aβ+ cognitively normal and Aβ+ mild cognitive impairment (P <.05) but not in Aβ+ AD dementia (P =.66). The prevalence was highest in Northern Europe but did not vary by sex or education. Discussion: The APOE ε4 prevalence in AD was higher than that in previous studies, which did not require presence of Aβ pathology. Furthermore, our results highlight disease heterogeneity related to age and geographical location.
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| 9. |
- Jansen, Willemijn J, et al.
(författare)
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Association of Cerebral Amyloid-β Aggregation With Cognitive Functioning in Persons Without Dementia.
- 2018
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Ingår i: JAMA psychiatry. - : American Medical Association (AMA). - 2168-6238 .- 2168-622X. ; 75:1, s. 84-95
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Tidskriftsartikel (refereegranskat)abstract
- Cerebral amyloid-β aggregation is an early event in Alzheimer disease (AD). Understanding the association between amyloid aggregation and cognitive manifestation in persons without dementia is important for a better understanding of the course of AD and for the design of prevention trials.To investigate whether amyloid-β aggregation is associated with cognitive functioning in persons without dementia.This cross-sectional study included 2908 participants with normal cognition and 4133 with mild cognitive impairment (MCI) from 53 studies in the multicenter Amyloid Biomarker Study. Normal cognition was defined as having no cognitive concerns for which medical help was sought and scores within the normal range on cognitive tests. Mild cognitive impairment was diagnosed according to published criteria. Study inclusion began in 2013 and is ongoing. Data analysis was performed in January 2017.Global cognitive performance as assessed by the Mini-Mental State Examination (MMSE) and episodic memory performance as assessed by a verbal word learning test. Amyloid aggregation was measured with positron emission tomography or cerebrospinal fluid biomarkers and dichotomized as negative (normal) or positive (abnormal) according to study-specific cutoffs. Generalized estimating equations were used to examine the association between amyloid aggregation and low cognitive scores (MMSE score ≤27 or memory z score≤-1.28) and to assess whether this association was moderated by age, sex, educational level, or apolipoprotein E genotype.Among 2908 persons with normal cognition (mean [SD] age, 67.4 [12.8] years), amyloid positivity was associated with low memory scores after age 70 years (mean difference in amyloid positive vs negative, 4% [95% CI, 0%-7%] at 72 years and 21% [95% CI, 10%-33%] at 90 years) but was not associated with low MMSE scores (mean difference, 3% [95% CI, -1% to 6%], P=.16). Among 4133 patients with MCI (mean [SD] age, 70.2 [8.5] years), amyloid positivity was associated with low memory (mean difference, 16% [95% CI, 12%-20%], P<.001) and low MMSE (mean difference, 14% [95% CI, 12%-17%], P<.001) scores, and this association decreased with age. Low cognitive scores had limited utility for screening of amyloid positivity in persons with normal cognition and those with MCI. In persons with normal cognition, the age-related increase in low memory score paralleled the age-related increase in amyloid positivity with an intervening period of 10 to 15 years.Although low memory scores are an early marker of amyloid positivity, their value as a screening measure for early AD among persons without dementia is limited.
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| 10. |
- Jansen, Willemijn J, et al.
(författare)
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Prevalence of cerebral amyloid pathology in persons without dementia: a meta-analysis.
- 2015
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Ingår i: JAMA. - : American Medical Association (AMA). - 1538-3598 .- 0098-7484. ; 313:19, s. 1924-38
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Tidskriftsartikel (refereegranskat)abstract
- Cerebral amyloid-β aggregation is an early pathological event in Alzheimer disease (AD), starting decades before dementia onset. Estimates of the prevalence of amyloid pathology in persons without dementia are needed to understand the development of AD and to design prevention studies.
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| 11. |
- Helbig, M., et al.
(författare)
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Warming response of peatland CO2 sink is sensitive to seasonality in warming trends
- 2022
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Ingår i: Nature Climate Change. - : Springer Science and Business Media LLC. - 1758-6798 .- 1758-678X. ; 12:8, s. 743-749
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Tidskriftsartikel (refereegranskat)abstract
- Peatlands have acted as net CO2 sinks over millennia, exerting a global climate cooling effect. Rapid warming at northern latitudes, where peatlands are abundant, can disturb their CO2 sink function. Here we show that sensitivity of peatland net CO2 exchange to warming changes in sign and magnitude across seasons, resulting in complex net CO2 sink responses. We use multiannual net CO2 exchange observations from 20 northern peatlands to show that warmer early summers are linked to increased net CO2 uptake, while warmer late summers lead to decreased net CO2 uptake. Thus, net CO2 sinks of peatlands in regions experiencing early summer warming, such as central Siberia, are more likely to persist under warmer climate conditions than are those in other regions. Our results will be useful to improve the design of future warming experiments and to better interpret large-scale trends in peatland net CO2 uptake over the coming few decades.
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| 12. |
- Herukka, S. K., et al.
(författare)
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Amyloid-beta and Tau Dynamics in Human Brain Interstitial Fluid in Patients with Suspected Normal Pressure Hydrocephalus
- 2015
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Ingår i: Journal of Alzheimers Disease. - : IOS Press. - 1387-2877 .- 1875-8908. ; 46:1, s. 261-269
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Tidskriftsartikel (refereegranskat)abstract
- Background: Amyloid-beta (A beta(1-42)), total tau (T-tau), and phosphorylated tau (P-tau(181)) in the cerebrospinal fluid (CSF) are the most promising biomarkers of Alzheimer's disease (AD). Still, little is known about the dynamics of these molecules in the living brain. In a transgenic mouse brain, soluble A beta decreases with increasing age and advanced A beta pathology as seen similarly in CSF. Objective: To assess the relationship between AD-related pathological changes in human brain tissue, ventricular and lumbar CSF, and brain interstitial fluid (ISF). Methods: Altogether 11 patients with suspected idiopathic normal pressure hydrocephalus underwent frontal cortical brain biopsy, 24-h intraventricular pressure monitoring, and a microdialysis procedure. AD-related biomarkers were analyzed from brain tissue, CSF, and ISF. Results: ISF T-tau levels decreased strongly within the first 12 h, then plateauing until the end of the experiment. A beta(1-42) and P-tau(181) remained stable during the experiment (n = 3). T-tau and P-tau were higher in the ISF than in ventricular or lumbar CSF, while A beta(1-42) levels were within similar range in both CSF and ISF samples. ISF P-tau correlated with the ventricular CSF T-tau (r = 0.70, p = 0.017) and P-tau(181) (r = 0.64, p = 0.034). Five patients with amyloid pathology in the brain biopsy tended to reveal lower ISF A beta(1-42) levels than those six without amyloid pathology. Conclusions: This is the first study to report ISF A beta and tau levels in the human brain without significant brain injury. The set-up used enables sampling from the brain ISF for at least 24 h without causing adverse effects due to the microdialysis procedure to follow the dynamics of the key molecules in AD pathogenesis in the living brain at various stages of the disease.
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| 13. |
- Leinonen, V., et al.
(författare)
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S- F-18 THK-5117-PET and C-11 PIB-PET Imaging in Idiopathic Normal Pressure Hydrocephalus in Relation to Confirmed Amyloid-beta Plaques and Tau in Brain Biopsies
- 2018
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Ingår i: Journal of Alzheimers Disease. - : IOS Press. - 1387-2877 .- 1875-8908. ; 64:1, s. 171-179
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Tidskriftsartikel (refereegranskat)abstract
- Background: Detection of pathological tau aggregates could facilitate clinical diagnosis of Alzheimer's disease (AD) and monitor drug effects in clinical trials. S-[F-18] THK-5117 could be a potential tracer to detect pathological tau deposits in brain. However, no previous study have correlated S-[F-18] THK-5117 uptake in PET with brain biopsy verified tau pathology in vivo. Objective: Here we aim to evaluate the association between cerebrospinal fluid (CSF) AD biomarkers, S-[F-18] THK-5117, and [C-11] PIB PET against tau and amyloid lesions in brain biopsy. Methods: Fourteen patients with idiopathic normal pressure hydrocephalus (iNPH) with previous shunt surgery including right frontal cortical brain biopsy and CSF A beta(1-42), total tau, and P-tau(181) measures, underwent brain MRI, [C-11] PIB PET, and S-[F-18] THK-5117 PET imaging. Results: Seven patients had amyloid-beta(A beta, 4G8) plaques, two both A beta and phosphorylated tau (P tau, AT8) and one only P tau in biopsy. As expected, increased brain biopsy A beta was well associated with higher [C-11] PIB uptake in PET. However, S-[F-18] THK-5117 uptake did not show any statistically significant correlation with either brain biopsy P tau or CSF P-tau(181) or total tau. Conclusions: S-[F-18] THK-5117 lacked clear association with neuropathologically verified tau pathology in brain biopsy probably, at least partially, due to off-target binding. Further studies with larger samples of patients with different tau tracers are urgently needed. The detection of simultaneous A beta and tau pathology in iNPH is important since that may indicate poorer and especially shorter response for CSF shunt surgery compared with no pathology.
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| 14. |
- Pyykkö, O. T., et al.
(författare)
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APOE4 predicts amyloid-β in cortical brain biopsy but not idiopathic normal pressure hydrocephalus
- 2012
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Ingår i: Journal of Neurology, Neurosurgery and Psychiatry. - : BMJ. - 0022-3050 .- 1468-330X. ; 83:11, s. 1119-1124
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To investigate the association of apolipoprotein E (APOE) genotype, especially the APOE4 allele, to (1) idiopathic normal pressure hydrocephalus (iNPH) and (2) amyloid-β (Aβ) plaques in cortical brain biopsies of presumed NPH patients with and without a final clinical diagnosis of Alzheimer's disease (AD). Methods: 202 patients with presumed NPH were evaluated by intraventricular pressure monitoring and frontal cortical biopsy immunostained against Aβ (134 semiquantified by Aβ plaques/mm 2). The 202 patients and 687 cognitively healthy individuals were genotyped for APOE. The final clinical diagnoses in a median follow-up of 3.9 years were: 113 iNPH (94 shunt responsive, 16 shunt non-responsive, three not shunted); 36 AD (12 mixed iNPH + AD); 53 others. Results: The APOE genotypes distributed similarly in the 94 shunt responsive and 16 non-responsive iNPH patients and healthy controls. In multivariate analysis, the APOE4 allele correlated independently with Aβ plaques in the cortical biopsies (OR 8.7, 95% CI 3.6 to 20, p<0.001). The APOE4 allele in presumed NPH predicted later AD as follows: sensitivity 61%; specificity 77%; positive predictive value 37%; negative predictive value 90%. Conclusion: In presumed NPH patients, APOE4 associates independently with the presence of Aβ plaques in the frontal cortical biopsy. APOE4 is not a risk factor for iNPH and does not predict the response to shunt. Our data further support the view that the iNPH syndrome is a distinct dementing disease.
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| 15. |
- Koivunen, J., et al.
(författare)
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PET amyloid ligand [C-11]PIB uptake shows predominantly striatal increase in variant Alzheimer's disease
- 2008
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Ingår i: Brain. - : Oxford University Press (OUP). - 0006-8950 .- 1460-2156. ; 131:Pt 7, s. 1845-1853
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Tidskriftsartikel (refereegranskat)abstract
- Variant Alzheimers disease (VarAD) with spastic paraparesis and presenile dementia is associated with certain mutations of the presenilin 1 (PS-1) gene, particularly those leading to deletion of exon 9 (PS-1 E9). VarAD is neuropathologically characterized by the presence of unusually large, A42 positive, non-cored cotton wool plaques (CWPs), also devoid of dystrophic neurites. The aim of the present study was to find out whether [C-11]PIB would show increased uptake and serve as an in vivo biomarker of amyloid accumulation in VarAD. A further aim was to assess the correspondence of the [C-11]PIB binding to the amount and type of A deposits in another group of deceased VarAD patients brains. We studied four patients with VarAD and eight healthy controls with PET using [C-11]PIB as tracer. Parametric images were computed by calculating the region-to-cerebellum and region-to-pons ratio in each voxel over 6090 min. Group differences in [C-11]PIB uptake were analysed with automated region-of-interest (ROI) analysis. [C-11]PIB uptake was compared to the immunohistochemically demonstrated deposition of A in the brains of another group of four deceased VarAD patients. Patients with VarAD had significantly higher [C-11] PIB uptake than the control group in the striatum (caudate nucleus and putamen), anterior and posterior cingulate gyrus, occipital cortex and thalamus. In the caudate and putamen [C-11]PIB uptake, expressed as region-to-cerebellum ratio, was on the average 43 greater than the mean of the control group. The increases in the anterior (28) and posterior (27) cingulate gyrus, occipital cortex (21) and thalamus (14) were smaller. All VarAD patients showed this similar topographical pattern of increased [C-11]PIB uptake. The results were essentially similar when the uptake was expressed as region-to-pons ratios. [C-11]PIB imaging shows increased uptake in patients with VarAD especially in the striatum, and it can be used to detect amyloid accumulation in vivo in these patients. The pattern of increased [C-11]PIB uptake is different from that described in sporadic Alzheimers disease and resembles that seen in Alzheimers disease patients with certain presenilin-1 mutations or amyloid precursor protein gene duplication showing predominantly striatal increase in [C-11]PIB uptake.
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| 16. |
- Seppala, T. T., et al.
(författare)
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CSF biomarkers for Alzheimer disease correlate with cortical brain biopsy findings
- 2012
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Ingår i: Neurology. - 0028-3878 .- 1526-632X. ; 78:20, s. 1568-1575
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To assess the relationship between Alzheimer disease (AD)-related pathologic changes in frontal cortical brain biopsy and AD biomarkers in ventricular vs lumbar CSF, and to evaluate the relationships of AD biomarkers in CSF and cortical biopsy with the final clinical diagnosis of AD. Methods: In 182 patients with presumed normal pressure hydrocephalus (152 with known APOE carrier status), A beta plaques and tau in the cortical brain biopsies were correlated with the ventricular and lumbar CSF A beta 42, total tau, and p-tau levels measured by ELISA. In a median follow-up of 2.0 years, 51 patients developed AD dementia. Results: The patients with A beta 42 plaques in the cortical biopsy had lower (p = 0.009) CSF A beta 42 levels than those with no A beta plaques. The patients with tau in the cortical biopsy had lower (p = 0.014) A beta 42 but higher (p = 0.015) p-tau 181 in CSF as compared to those with no tau in the cortical biopsy. The patients with amyloid + tau + biopsies had the lowest A beta 42 and highest tau and p-tau 181 levels in CSF. The A beta 42 levels were lower and the tau and p-tau 181 higher in the ventricular vs corresponding lumbar CSF samples. In multivariate analysis, the presence of cortical A beta was independently predicted by the APOE epsilon 4 carrier status and age but not by CSF A beta 42 or tau levels. Conclusions: Amyloid plaques and hyperphosphorylated tau in cortical brain biopsies are reflected by low CSF A beta 42 and high CSF tau and p-tau levels, respectively. Neurology (R) 2012;78:1568-1575
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| 17. |
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| 18. |
- Snellman, Anniina, et al.
(författare)
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APOE epsilon 4 gene dose effect on imaging and blood biomarkers of neuroinflammation and beta-amyloid in cognitively unimpaired elderly
- 2023
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Ingår i: Alzheimers Research & Therapy. - 1758-9193. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundNeuroinflammation, characterized by increased reactivity of microglia and astrocytes in the brain, is known to be present at various stages of the Alzheimer's disease (AD) continuum. However, its presence and relationship with amyloid pathology in cognitively normal at-risk individuals is less clear. Here, we used positron emission tomography (PET) and blood biomarker measurements to examine differences in neuroinflammation and beta-amyloid (A beta) and their association in cognitively unimpaired homozygotes, heterozygotes, or non-carriers of the APOE epsilon 4 allele, the strongest genetic risk for sporadic AD.MethodsSixty 60-75-year-old APOE epsilon 4 homozygotes (n = 19), heterozygotes (n = 21), and non-carriers (n = 20) were recruited in collaboration with the local Auria biobank. The participants underwent C-11-PK11195 PET (targeting 18-kDa translocator protein, TSPO), C-11-PiB PET (targeting A beta), brain MRI, and neuropsychological testing including a preclinical cognitive composite (APCC). C-11-PK11195 distribution volume ratios and C-11-PiB standardized uptake value ratios (SUVRs) were calculated for regions typical for early A beta accumulation in AD. Blood samples were drawn for measuring plasma glial fibrillary acidic protein (GFAP) and plasma A beta(1-42/1.40).ResultsIn our cognitively unimpaired sample, cortical C-11-PiB-binding increased according to APOE epsilon 4 gene dose (median composite SUVR 1.47 (range 1.38-1.66) in non-carriers, 1.55 (1.43-2.02) in heterozygotes, and 2.13 (1.61-2.83) in homozygotes, P = 0.002). In contrast, cortical composite C-11-PK11195-binding did not differ between the APOE epsilon 4 gene doses (P = 0.27) or between A beta-positive and A beta-negative individuals (P = 0.81) and associated with higher A beta burden only in APOE epsilon 4 homozygotes (Rho = 0.47, P = 0.043). Plasma GFAP concentration correlated with cortical C-11-PiB (Rho = 0.35, P = 0.040), but not C-11-PK11195-binding (Rho = 0.13, P = 0.47) in A beta-positive individuals. In the total cognitively unimpaired population, both higher composite C-11-PK11195-binding and plasma GFAP were associated with lower hippocampal volume, whereas elevated C-11-PiB-binding was associated with lower APCC scores.ConclusionsOnly A beta burden measured by PET, but not markers of neuroinflammation, differed among cognitively unimpaired elderly with different APOE epsilon 4 gene dose. However, APOE epsilon 4 gene dose seemed to modulate the association between neuroinflammation and A beta.
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| 19. |
- Snellman, Anniina, et al.
(författare)
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ASIC-E4: Interplay of Beta-Amyloid, Synaptic Density and Neuroinflammation in Cognitively Normal Volunteers With Three Levels of Genetic Risk for Late-Onset Alzheimer's Disease - Study Protocol and Baseline Characteristics
- 2022
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Ingår i: Frontiers in Neurology. - : Frontiers Media SA. - 1664-2295. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Background:& nbsp;Detailed characterization of early pathophysiological changes in preclinical Alzheimer's disease (AD) is necessary to enable development of correctly targeted and timed disease-modifying treatments. ASIC-E4 study ( "Beta-Amyloid, Synaptic loss, Inflammation and Cognition in healthy APOE epsilon 4 carriers ") combines state-of-the-art neuroimaging and fluid-based biomarker measurements to study the early interplay of three key pathological features of AD, i.e., beta-amyloid (A beta) deposition, neuroinflammation and synaptic dysfunction and loss in cognitively normal volunteers with three different levels of genetic (APOE-related) risk for late-onset AD.& nbsp;Objective:& nbsp;Here, our objective is to describe the study design, used protocols and baseline demographics of the ASIC-E4 study.& nbsp;Methods/Design:& nbsp;ASIC-E4 is a prospective observational multimodal imaging study performed in Turku PET Centre in collaboration with University of Gothenburg. Cognitively normal 60-75-year-old-individuals with known APOE epsilon 4/epsilon 4 genotype were recruited via local Auria Biobank (Turku, Finland). Recruitment of the project has been completed in July 2020 and 63 individuals were enrolled to three study groups (Group 1: APOE epsilon 4/epsilon 4, N = 19; Group 2: APOE epsilon 4/epsilon 3, N = 22; Group 3: APOE epsilon 3/epsilon 3, N = 22). At baseline, all participants will undergo positron emission tomography imaging with tracers targeted against A beta deposition (C-11-PIB), activated glia (C-11-PK11195) and synaptic vesicle glycoprotein 2A (C-11-UCB-J), two brain magnetic resonance imaging scans, and extensive cognitive testing. In addition, blood samples are collected for various laboratory measurements and blood biomarker analysis and cerebrospinal fluid samples are collected from a subset of participants based on additional voluntary informed consent. To evaluate the predictive value of the early neuroimaging findings, neuropsychological evaluation and blood biomarker measurements will be repeated after a 4-year follow-up period.& nbsp;Discussion:& nbsp;Results of the ASIC-E4 project will bridge the gap related to limited knowledge of the synaptic and inflammatory changes and their association with each other and A beta in "at-risk " individuals. Thorough in vivo characterization of the biomarker profiles in this population will produce valuable information for diagnostic purposes and future drug development, where the field has already started to look beyond A beta.
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| 20. |
- Allard, Per, et al.
(författare)
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Dopamine uptake sites in Parkinson's disease and in dementia of the Alzheimer type.
- 1994
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Ingår i: Brain Research. - 0006-8993 .- 1872-6240. ; 637:1-2, s. 262-6
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Tidskriftsartikel (refereegranskat)abstract
- The binding of [3H]GBR-12935 to dopamine (DA) uptake sites was studied in post-mortem putamen from a control group and from patients with Parkinson's disease (PD) or dementia of the Alzheimer type (DAT). The specific binding (Bmax) was almost completely abolished in the PD group and reduced by 65% in the DAT group. There were no significant differences in apparent binding affinity (Kd) between the DAT group and controls. The decreases in [3H]GBR-12935 binding to DA uptake sites in this study indicate a marked degeneration of DA neurites in the putamen in PD and also in DAT.
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| 21. |
- Artaxo, Paulo, et al.
(författare)
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Tropical and Boreal Forest – Atmosphere Interactions : A Review
- 2022
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Ingår i: Tellus. Series B, Chemical and physical meteorology. - : Stockholm University Press. - 0280-6509 .- 1600-0889. ; 74:1, s. 24-163
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Forskningsöversikt (refereegranskat)abstract
- This review presents how the boreal and the tropical forests affect the atmosphere, its chemical composition, its function, and further how that affects the climate and, in return, the ecosystems through feedback processes. Observations from key tower sites standing out due to their long-term comprehensive observations: The Amazon Tall Tower Observatory in Central Amazonia, the Zotino Tall Tower Observatory in Siberia, and the Station to Measure Ecosystem-Atmosphere Relations at Hyytiäla in Finland. The review is complemented by short-term observations from networks and large experiments.The review discusses atmospheric chemistry observations, aerosol formation and processing, physiochemical aerosol, and cloud condensation nuclei properties and finds surprising similarities and important differences in the two ecosystems. The aerosol concentrations and chemistry are similar, particularly concerning the main chemical components, both dominated by an organic fraction, while the boreal ecosystem has generally higher concentrations of inorganics, due to higher influence of long-range transported air pollution. The emissions of biogenic volatile organic compounds are dominated by isoprene and monoterpene in the tropical and boreal regions, respectively, being the main precursors of the organic aerosol fraction.Observations and modeling studies show that climate change and deforestation affect the ecosystems such that the carbon and hydrological cycles in Amazonia are changing to carbon neutrality and affect precipitation downwind. In Africa, the tropical forests are so far maintaining their carbon sink.It is urgent to better understand the interaction between these major ecosystems, the atmosphere, and climate, which calls for more observation sites, providing long-term data on water, carbon, and other biogeochemical cycles. This is essential in finding a sustainable balance between forest preservation and reforestation versus a potential increase in food production and biofuels, which are critical in maintaining ecosystem services and global climate stability. Reducing global warming and deforestation is vital for tropical forests.
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| 22. |
- Kallionpaa, R. A., et al.
(författare)
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Increased risk for dementia in neurofibromatosis type 1
- 2021
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Ingår i: Genetics in Medicine. - : Elsevier BV. - 1098-3600.
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Tidskriftsartikel (refereegranskat)abstract
- Purpose To determine the risk for dementia in neurofibromatosis type 1 (NF1) using a Finnish nationwide cohort of individuals with NF1, and data from national registries. Methods A Finnish cohort of 1,349 individuals with confirmed NF1 according to the US National Institutes of Health (NIH) diagnostic criteria was compared with a control cohort of 13,870 individuals matched for age, sex, and area of residence. Dementia-related hospital visits were retrieved from the Finnish Care Register for Health Care using International Classification of Diseases, 10th revision (ICD-10) diagnosis codes G30 and F00-F03. Purchases of antidementia drugs were queried with Anatomical Therapeutic Chemical (ATC) classification code N06D from the drug reimbursement register maintained by the Social Insurance Institution of Finland. The follow-up spanned 1998-2014. Results Totals of 16 and 165 individuals with at least two dementia-related diagnoses or drug purchases were identified in the NF1 and control cohorts, respectively. The hazard ratio for dementia in NF1 was 1.67 (95% confidence interval [CI] 1.00-2.80, P = 0.050). In an analysis stratified by the type of dementia, the risk for Alzheimer disease was increased in NF1 compared to controls with a hazard ratio of 2.88 (95% CI 1.47-5.66, P = 0.002). Conclusion Dementia and especially Alzheimer disease are previously unrecognized neurological complications of NF1.
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| 23. |
- Luoma, Petri, et al.
(författare)
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Parkinsonism, premature menopause, and mitochondrial DNA polymerase gamma mutations: clinical and molecular genetic study
- 2004
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Ingår i: Lancet. ; 364:9437, s. 875-82
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Mutations in the gene encoding mitochondrial DNA polymerase gamma (POLG), the enzyme that synthesises mitochondrial DNA (mtDNA), have been associated with a mitochondrial disease-autosomal dominant or recessive progressive external ophthalmoplegia-and multiple deletions of mtDNA. Mitochondrial dysfunction is also suspected to participate in the pathogenesis of Parkinson's disease. However, no primary gene defects affecting mitochondrial proteins causing mendelian transmission of parkinsonism have been characterised. We aimed to analyse the gene sequence of POLG in patients with progressive external ophthalmoplegia and their healthy relatives. METHODS: In seven families of various ethnic origins we assessed patients with progressive external ophthalmoplegia and unaffected individuals by clinical, biochemical, morphological, and molecular genetic characterisation and positron emission tomography (PET). FINDINGS: We recorded mutations in POLG in members of all seven families. Clinical assessment showed significant cosegregation of parkinsonism with POLG mutations (p<0.0001), and PET findings were consistent with dopaminergic neuron loss. Post-mortem examination in two individuals showed loss of pigmented neurons and pigment phagocytosis in substantia nigra without Lewy bodies. Furthermore, most women with progressive external ophthalmoplegia had early menopause-before age 35 years. The POLG gene defect resulted in secondary accumulation of mtDNA deletions in patients' tissues. INTERPRETATION: Dysfunction of mitochondrial POLG causes a severe progressive multisystem disorder including parkinsonism and premature menopause, which are not typical of mitochondrial disease. Cosegregation of parkinsonism and POLG mutations in our families suggests that when defective, this gene can underlie mendelian transmission of parkinsonism. RELEVANCE TO PRACTICE: Awareness that mitochondrial POLG mutations can underlie parkinsonism is important for clinicians working in diagnosis of movement disorders, as well as for studies of the genetics of Parkinson's disease. Further, progressive external ophthalmoplegia with muscle weakness and neuropathy can mask symptoms of parkinsonism, and clinicians should pay special attention to detect and treat parkinsonism in those individuals.
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| 24. |
- Snellman, Anniina, et al.
(författare)
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Head-to-head comparison of plasma p-tau181, p-tau231 and glial fibrillary acidic protein in clinically unimpaired elderly with three levels of APOE4-related risk for Alzheimer's disease
- 2023
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Ingår i: Neurobiology of Disease. - 0969-9961. ; 183
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Tidskriftsartikel (refereegranskat)abstract
- Plasma phosphorylated tau (p-tau) and glial fibrillary acidic protein (GFAP) both reflect early changes in Alzheimer's disease (AD) pathology. Here, we compared the biomarker levels and their association with regional S-amyloid (AS) pathology and cognitive performance head-to-head in clinically unimpaired elderly (n = 88) at three levels of APOE4-related genetic risk for sporadic AD (APOE4/4 n = 19, APOE3/4 n = 32 or non-carriers n = 37). Concentrations of plasma p-tau181, p-tau231 and GFAP were measured using Single molecule array (Simoa), regional AS deposition with 11C-PiB positron emission tomography (PET), and cognitive performance with a preclinical composite. Significant differences in plasma p-tau181 and p-tau231, but not plasma GFAP concentrations were present between the APOE4 gene doses, explained solely by brain AS load. All plasma biomarkers correlated positively with AS PET in the total study population. This correlation was driven by APOE3/3 carriers for plasma p-tau markers and APOE4/4 carriers for plasma GFAP. Voxel-wise associations with amyloid-PET revealed different spatial patterns for plasma p-tau markers and plasma GFAP. Only higher plasma GFAP correlated with lower cognitive scores. Our observations suggest that plasma p-tau and plasma GFAP are both early AD markers reflecting different AS-related processes.
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| 25. |
- Alakurtti, Kati, et al.
(författare)
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Long-term test-retest reliability of striatal and extrastriatal dopamine D-2/3 receptor binding : study with [C-11]raclopride and high-resolution PET
- 2015
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Ingår i: Journal of Cerebral Blood Flow and Metabolism. - : SAGE Publications. - 0271-678X .- 1559-7016. ; 35:7, s. 1199-1205
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Tidskriftsartikel (refereegranskat)abstract
- We measured the long-term test-retest reliability of [C-11]raclopride binding in striatal subregions, the thalamus and the cortex using the bolus-plus-infusion method and a high-resolution positron emission scanner. Seven healthy male volunteers underwent two positron emission tomography (PET) [C-11]raclopride assessments, with a 5-week retest interval. D-2/3 receptor availability was quantified as binding potential using the simplified reference tissue model. Absolute variability (VAR) and intraclass correlation coefficient (ICC) values indicated very good reproducibility for the striatum and were 4.5%/0.82, 3.9%/0.83, and 3.9%/0.82, for the caudate nucleus, putamen, and ventral striatum, respectively. Thalamic reliability was also very good, with VAR of 3.7% and ICC of 0.92. Test-retest data for cortical areas showed good to moderate reproducibility (6.1% to 13.1%). Our results are in line with previous test-retest studies of [C-11]raclopride binding in the striatum. A novel finding is the relatively low variability of [C-11]raclopride binding, providing suggestive evidence that extrastriatal D-2/3 binding can be studied in vivo with [C-11]raclopride PET to be verified in future studies.
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| 26. |
- Konki, Mikko, et al.
(författare)
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Peripheral blood DNA methylation differences in twin pairs discordant for Alzheimer's disease.
- 2019
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Ingår i: Clinical Epigenetics. - : BioMed Central. - 1868-7083 .- 1868-7075. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Alzheimer's disease results from a neurodegenerative process that starts well before the diagnosis can be made. New prognostic or diagnostic markers enabling early intervention into the disease process would be highly valuable. Environmental and lifestyle factors largely modulate the disease risk and may influence the pathogenesis through epigenetic mechanisms, such as DNA methylation. As environmental and lifestyle factors may affect multiple tissues of the body, we hypothesized that the disease-associated DNA methylation signatures are detectable in the peripheral blood of discordant twin pairs.RESULTS: Comparison of 23 disease discordant Finnish twin pairs with reduced representation bisulfite sequencing revealed peripheral blood DNA methylation differences in 11 genomic regions with at least 15.0% median methylation difference and FDR adjusted p value ≤ 0.05. Several of the affected genes are primarily associated with neuronal functions and pathologies and do not display disease-associated differences in gene expression in blood. The DNA methylation mark in ADARB2 gene was found to be differentially methylated also in the anterior hippocampus, including entorhinal cortex, of non-twin cases and controls. Targeted bisulfite pyrosequencing of the DNA methylation mark in ADARB2 gene in 62 Finnish and Swedish twin pairs revealed that, in addition to the disease status, DNA methylation of this region is influenced by gender, age, zygosity, APOE genotype, and smoking. Further analysis of 120 Swedish twin pairs indicated that this specific DNA methylation mark is not predictive for Alzheimer's disease and becomes differentially methylated after disease onset.CONCLUSIONS: DNA methylation differences can be detected in the peripheral blood of twin pairs discordant for Alzheimer's disease. These DNA methylation signatures may have value as disease markers and provide insights into the molecular mechanisms of pathogenesis. We found no evidence that the DNA methylation marks would be associated with gene expression in blood. Further studies are needed to elucidate the potential importance of the associated genes in neuronal functions and to validate the prognostic or diagnostic value of the individual marks or marker panels.
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| 27. |
- Rinne, Juha O, et al.
(författare)
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11C-PiB PET assessment of change in fibrillar amyloid-beta load in patients with Alzheimer's disease treated with bapineuzumab: a phase 2, double-blind, placebo-controlled, ascending-dose study.
- 2010
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Ingår i: Lancet neurology. - 1474-4465. ; 9:4, s. 363-72
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Carbon-11-labelled Pittsburgh compound B ((11)C-PiB) PET is a marker of cortical fibrillar amyloid-beta load in vivo. We used (11)C-PiB PET to investigate whether bapineuzumab, a humanised anti-amyloid-beta monoclonal antibody, would reduce cortical fibrillar amyloid-beta load in patients with Alzheimer's disease. METHODS: Patients with mild-to-moderate Alzheimer's disease were randomly assigned to receive intravenous bapineuzumab or placebo in a ratio of seven to three in three ascending dose groups (0.5, 1.0, or 2.0 mg/kg). Each dose group was enrolled after safety review of the previous group. Randomisation was by interactive voice response system; masking was achieved with numbered kit allocation. Patients, investigators, study site personnel, sponsor staff, and carers were masked to treatment. Patients received up to six infusions, 13 weeks apart, and had (11)C-PiB PET scans at baseline and at weeks 20, 45, and 78. The primary outcome was the difference between the pooled bapineuzumab group and the pooled placebo group in mean change from screening to week 78 in (11)C-PiB cortical to cerebellar retention ratio averaged across six cortical regions of interest. Analysis was by modified intention to treat. This study is registered with EudraCT, number 2004-004120-12; ISRCTN17517446. FINDINGS: 28 patients were assigned to bapineuzumab (n=20) or placebo (n=8). 19 patients in the bapineuzumab group and seven in the placebo group were included in the modified intention-to-treat analysis. Estimated mean (11)C-PiB retention ratio change from baseline to week 78 was -0.09 (95% CI -0.16 to -0.02; p=0.014) in the bapineuzumab group and 0.15 (95% CI 0.02 to 0.28; p=0.022) in the placebo group. Estimated mean difference in (11)C-PiB retention ratio change from baseline to week 78 between the bapineuzumab group and the placebo group was -0.24 (95% CI -0.39 to -0.09; p=0.003). Differences between the bapineuzumab group and the placebo group in the individual regions of interest were similar to the overall mean difference. Adverse events were typically mild to moderate in severity and transient. Two patients in the 2.0 mg/kg bapineuzumab group had transient cerebral vasogenic oedema. INTERPRETATION: Treatment with bapineuzumab for 78 weeks reduced cortical (11)C-PiB retention compared with both baseline and placebo. (11)C-PiB PET seems to be useful in assessing the effects of potential Alzheimer's disease treatments on cortical fibrillar amyloid-beta load in vivo. FUNDING: Elan Pharmaceuticals and Wyeth Research.
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| 28. |
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| 29. |
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| 30. |
- Wolk, David A., et al.
(författare)
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Use of flutemetamol F18-labeled positron emission tomography and other biomarkers to assess risk of clinical progression in patients with amnestic mild cognitive impairment
- 2018
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Ingår i: JAMA Neurology. - : American Medical Association (AMA). - 2168-6149. ; 75:9, s. 1114-1123
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Tidskriftsartikel (refereegranskat)abstract
- Importance: Patients with amnestic mild cognitive impairment (aMCI) may progress to clinical Alzheimer disease (AD), remain stable, or revert to normal. Earlier progression to AD among patients who were β-amyloid positive vs those who were β-amyloid negative has been previously observed. Current research now accepts that a combination of biomarkers could provide greater refinement in the assessment of risk for clinical progression. Objective: To evaluate the ability of flutemetamol F 18 and other biomarkers to assess the risk of progression from aMCI to probable AD. Design, Setting, and Participants: In this multicenter cohort study, from November 11, 2009, to January 16, 2014, patients with aMCI underwent positron emission tomography (PET) at baseline followed by local clinical assessments every 6 months for up to 3 years. Patients with aMCI (365 screened; 232 were eligible) were recruited from 28 clinical centers in Europe and the United States. Physicians remained strictly blinded to the results of PET, and the standard of truth was an independent clinical adjudication committee that confirmed or refuted local assessments. Flutemetamol F 18-labeled PET scans were read centrally as either negative or positive by 5 blinded readers with no knowledge of clinical status. Statistical analysis was conducted from February 19, 2014, to January 26, 2018. Interventions: Flutemetamol F 18-labeled PET at baseline followed by up to 6 clinical visits every 6 months, as well as magnetic resonance imaging and multiple cognitive measures. Main Outcomes and Measures: Time from PET to probable AD or last follow-upwas plotted as a Kaplan-Meier survival curve; PET scan results, age, hippocampal volume, and aMCI stage were entered into Cox proportional hazards logistic regression analyses to identify variables associated with progression to probable AD. Results: Of 232 patients with aMCI (118 women and 114 men; mean [SD] age, 71.1 [8.6] years), 98 (42.2%) had positive results detected on PET scan. By 36 months, the rates of progression to probable AD were 36.2% overall (81 of 224 patients), 53.6%(52 of 97) for patients with positive results detected on PET scan, and 22.8% (29 of 127) for patients with negative results detected on PET scan. Hazard ratios for association with progression were 2.51 (95% CI, 1.57-3.99; P < .001) for a positive β-amyloid scan alone (primary outcome measure), 5.60 (95%CI, 3.14-9.98; P < .001) with additional low hippocampal volume, and 8.45 (95%CI, 4.40-16.24; P < .001) when poorer cognitive status was added to the model. Conclusions and Relevance: A combination of positive results of flutemetamol F 18-labeled PET, low hippocampal volume, and cognitive status corresponded with a high probability of risk of progression from aMCI to probable AD within 36 months.
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