| 61. |
- Kumar, Atul, et al.
(författare)
-
Genetic influence during the early phases of Alzheimer's disease on longitudinal cognitive impairment
- 2021
-
Ingår i: Alzheimer's & dementia : the journal of the Alzheimer's Association. - 1552-5279. ; 17
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The rate of cognitive decline in the early stages of Alzheimer's disease (AD) is variable, which may be partly due to genetic factors. We therefore investigated genetic predictors of longitudinal cognitive decline in AD. METHOD: In the Swedish BioFINDER study, we used polygenic scores (PGS) (of AD, intelligence and educational attainment), and genetic variants (in a genome-wide association study [GWAS]) to predict longitudinal change in cognition (measured by MMSE) over a mean of 4.2 years. We included 555 b-amyloid (Aβ) negative cognitively unimpaired (CU) individuals, 206 Aβ-positive CU (preclinical AD), 110 Aβ-negative mild cognitive impairment (MCI) patients, and 146 Aβ-positive MCI patients (prodromal AD). Mixed-effect models were fitted with longitudinal MMSE data as dependent variable. Random slopes and intercepts were extracted and were rank-based inverse normal transformed (INT) to be used as dependent variables in linear regression models. RESULT: AD polygenic risk score (PRS) and intelligence PGS (but not education PGS) were associated with rate of cognitive decline (Figure 1). The AD PRS was only associated with decline in Ab-positive individuals, but the intelligence PGS was protective irrespective of Ab-status (Figure 2). The model containing only the APOE burden (ε4 and ε2 counts) was associated with cognitive decline with a nominal level of significance, whereas this was not found for the early-stage AD cohort (Figure 1 and 2). Our GWAS identified 8 genes (out of which 3 genes independent of Aβ-status) associated with rate of cognitive decline at a p-value ≤ 5e-05 (Table 1). CONCLUSION: An a priori defined genetic risk score for AD was only associated with rate of cognitive decline in early stage AD (Aβ+ CU and Aβ+ MCI) and not in an unselected population, while a polygenic score for intelligence was protective irrespective of Aβ status. Together with novel genetic associations for rate of cognitive decline in AD, this may provide new insights into the pathophysiology of AD and new therapeutic development targets.
|
|
| 62. |
- Kumar, Atul, et al.
(författare)
-
Genetic interaction study of Alzheimer's disease quantitative biomarkers : A polygenic risk score analysis and evaluation
- 2021
-
Ingår i: Alzheimer's & dementia : the journal of the Alzheimer's Association. - 1552-5279. ; 17
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Relationship between genetic factors and pathological features of Alzheimer's disease (AD) may be studied with biomarker, using both polygenic risk scores (PRSs), as well as individual genetic variants in genome-wide association studies (GWAS). METHOD: In the Swedish BioFINDER study, we used a priori PRS for AD based on findings in recent GWAS, and AD related biomarkers in cerebrospinal fluid (CSF) in cognitively unimpaired individuals (n = 751), Mild Cognitive Impairment (n = 212), and AD (n = 150) patients. AD related biomarkers were rank-based inverse normal transformed to be used as dependent variables in linear regression models adjusted for age, gender, education, APOE ε4, ε2 count and significant principal components. We also tested individual genetic variants in GWAS for each biomarker. Analyses were performed in the total sample, and after stratification on MMSE results. RESULT: The PRS was associated with higher CSF P-tau 181 (p ≤1.2e-05) and T-tau (p ≤ 8.14e-05) and lower CSF Aβ42/40 (p ≤ 0.006) and Aβ42 (p ≤ 0.04) (Figure 1, 2). Gene Enrichment of PRS 5 genes [containing 1850 genetic variants mapped to 1607 genes] for Tau biomarker showed 13 Gene Ontology (GO) Biological Process (BP) terms at p-value < e-03 ("Dendrite Morphogenesis": top hit; p-value ≤ 9.20e-06) and 16 KEGG pathway term enriched for genes of PRS 5 ("Phosphatidylinositol signaling system": top hit; p-value ≤ 5.5e-06) (Figure 3, 4). Gene enrichment of PRS 7 [containing 62 genetic variants mapped to 58 genes] for Aβ biomarker returned 12 GO terms ("Integrin-Mediated Signaling Pathway": top hit; p-value ≤1.20e-03) and 1 term enriched for KEGG pathway (Hematopoietic cell lineage). In our predefined list of genes interacting with MAPT (22 genes) and APP (69 genes) we found 3 genes from MAPT and APP set that were involved in PRS 5 and PRS 7 respectively. We also found 9 genes from APP set that was involved in PRS 5. CONCLUSION: Elevated levels of AD related biomarkers are associated with polygenic risk scores in AD. These findings further strengthens the link between genetic and biomarker disease predictors and indicate a potential role for these markers in disease prediction and patient stratification in AD.
|
|
| 63. |
- Lanza, Nina L., et al.
(författare)
-
Oxidation of manganese in an ancient aquifer, Kimberley formation, Gale crater, Mars
- 2016
-
Ingår i: Geophysical Research Letters. - 0094-8276 .- 1944-8007. ; 43:14, s. 7398-7407
-
Tidskriftsartikel (refereegranskat)abstract
- The Curiosity rover observed high Mn abundances (>25wt % MnO) in fracture-filling materials that crosscut sandstones in the Kimberley region of Gale crater, Mars. The correlation between Mn and trace metal abundances plus the lack of correlation between Mn and elements such as S, Cl, and C, reveals that these deposits are Mn oxides rather than evaporites or other salts. On Earth, environments that concentrate Mn and deposit Mn minerals require water and highly oxidizing conditions; hence, these findings suggest that similar processes occurred on Mars. Based on the strong association between Mn-oxide deposition and evolving atmospheric dioxygen levels on Earth, the presence of these Mn phases on Mars suggests that there was more abundant molecular oxygen within the atmosphere and some groundwaters of ancient Mars than in the present day
|
|
| 64. |
- Laverse, Etienne, et al.
(författare)
-
Plasma glial fibrillary acidic protein and neurofilament light chain, but not tau, are biomarkers of sports-related mild traumatic brain injury.
- 2020
-
Ingår i: Brain communications. - : Oxford University Press (OUP). - 2632-1297. ; 2:2
-
Tidskriftsartikel (refereegranskat)abstract
- Mild traumatic brain injury is a relatively common event in contact sports and there is increasing interest in the long-term neurocognitive effects. The diagnosis largely relies on symptom reporting and there is a need for objective tools to aid diagnosis and prognosis. There are recent reports that blood biomarkers could potentially help triage patients with suspected injury and normal CT findings. We have measured plasma concentrations of glial and neuronal proteins and explored their potential in the assessment of mild traumatic brain injury in contact sport. We recruited a prospective cohort of active male rugby players, who had pre-season baseline plasma sampling. From this prospective cohort, we recruited 25 players diagnosed with mild traumatic brain injury. We sampled post-match rugby players without head injuries as post-match controls. We measured plasma neurofilament light chain, tau and glial fibrillary acidic protein levels using ultrasensitive single molecule array technology. The data were analysed at the group and individual player level. Plasma glial fibrillary acidic protein concentration was significantly increased 1-h post-injury in mild traumatic brain injury cases compared to the non-injured group (P=0.017). Pairwise comparison also showed that glial fibrillary acidic protein levels were higher in players after a head injury in comparison to their pre-season levels at both 1-h and 3- to 10-day post-injury time points (P=0.039 and 0.040, respectively). There was also an increase in neurofilament light chain concentration in brain injury cases compared to the pre-season levels within the same individual at both time points (P=0.023 and 0.002, respectively). Tau was elevated in both the non-injured control group and the 1-h post-injury group compared to pre-season levels (P=0.007 and 0.015, respectively). Furthermore, receiver operating characteristic analysis showed that glial fibrillary acidic protein and neurofilament light chain can separate head injury cases from control players. The highest diagnostic power was detected when biomarkers were combined in differentiating 1-h post-match control players from 1-h post-head injury players (area under curve 0.90, 95% confidence interval 0.79-1.00, P<0.0002). The brain astrocytic marker glial fibrillary acidic protein is elevated in blood 1h after mild traumatic brain injury and in combination with neurofilament light chain displayed the potential as a reliable biomarker for brain injury evaluation. Plasma total tau is elevated following competitive rugby with and without a head injury, perhaps related to peripheral nerve trauma and therefore total tau does not appear to be suitable as a blood biomarker.
|
|
| 65. |
- Ling, Helen, et al.
(författare)
-
Neurological consequences of traumatic brain injuries in sports.
- 2015
-
Ingår i: Molecular and cellular neurosciences. - : Elsevier BV. - 1095-9327 .- 1044-7431. ; 66:Part B, s. 114-122
-
Tidskriftsartikel (refereegranskat)abstract
- Traumatic brain injury (TBI) is common in boxing and other contact sports. The long term irreversible and progressive aftermath of TBI in boxers depicted as punch drunk syndrome was described almost a century ago and is now widely referred as chronic traumatic encephalopathy (CTE). The short term sequelae of acute brain injury including subdural haematoma and catastrophic brain injury may lead to death, whereas mild TBI, or concussion, causes functional disturbance and axonal injury rather than gross structural brain damage. Following concussion, symptoms such as dizziness, nausea, reduced attention, amnesia and headache tend to develop acutely but usually resolve within a week or two. Severe concussion can also lead to loss of consciousness. Despite the transient nature of the clinical symptoms, functional neuroimaging, electrophysiological, neuropsychological and neurochemical assessments indicate that the disturbance of concussion takes over a month to return to baseline and neuropathological evaluation shows that concussion-induced axonopathy may persist for years. The developing brains in children and adolescents are more susceptible to concussion than adult brain. The mechanism by which acute TBI may lead to the neurodegenerative process of CTE associated with tau hyperphosphorylation and the development of neurofibrillary tangles (NFTs) remains speculative. Focal tau-positive NFTs and neurites in close proximity to focal axonal injury and foci of microhaemorrhage and the predilection of CTE-tau pathology for perivascular and subcortical regions suggest that acute TBI-related axonal injury, loss of microvascular integrity, breach of the blood brain barrier, resulting inflammatory cascade and microglia and astrocyte activation are likely to be the basis of the mechanistic link of TBI and CTE. This article provides an overview of the acute and long-term neurological consequences of TBI in sports. Clinical, neuropathological and the possible pathophysiological mechanisms are discussed. This article is part of a Special Issue entitled 'Traumatic Brain Injury'.
|
|
| 66. |
- Ly, Han, et al.
(författare)
-
The association of circulating amylin with β-amyloid in familial Alzheimer's disease.
- 2021
-
Ingår i: Alzheimer's & dementia. - : Wiley. - 2352-8737. ; 7:1
-
Tidskriftsartikel (refereegranskat)abstract
- This study assessed the hypothesis that circulating human amylin (amyloid-forming) cross-seeds with amyloid beta (Aβ) in early Alzheimer's disease (AD).Evidence of amylin-AD pathology interaction was tested in brains of 31 familial AD mutation carriers and 20 cognitively unaffected individuals, in cerebrospinal fluid (CSF) (98 diseased and 117 control samples) and in genetic databases. For functional testing, we genetically manipulated amylin secretion in APP/PS1 and non-APP/PS1 rats.Amylin-Aβ cross-seeding was identified in AD brains. High CSF amylin levels were associated with decreased CSF Aβ42 concentrations. AD risk and amylin gene are not correlated. Suppressed amylin secretion protected APP/PS1 rats against AD-associated effects. In contrast, hypersecretion or intravenous injection of human amylin in APP/PS1 rats exacerbated AD-like pathology through disruption of CSF-brain Aβ exchange and amylin-Aβ cross-seeding.These findings strengthened the hypothesis of circulating amylin-AD interaction and suggest that modulation of blood amylin levels may alter Aβ-related pathology/symptoms.
|
|
| 67. |
- Mattsson, Niklas, 1979, et al.
(författare)
-
Selective vulnerability in neurodegeneration: insights from clinical variants of Alzheimer's disease.
- 2016
-
Ingår i: Journal of neurology, neurosurgery, and psychiatry. - : BMJ. - 1468-330X .- 0022-3050. ; 87:9, s. 1000-1004
-
Tidskriftsartikel (refereegranskat)abstract
- Selective vulnerability in the nervous system refers to the fact that subpopulations of neurons in different brain systems may be more or less prone to abnormal function or death in response to specific types of pathological states or injury. The concept has been used extensively as a potential way of explaining differences in degeneration patterns and the clinical presentation of different neurodegenerative diseases. Yet the increasing complexity of molecular histopathology at the cellular level in neurodegenerative disorders frequently appears at odds with phenotyping based on clinically-directed, macroscopic regional brain involvement. While cross-disease comparisons can provide insights into the differential vulnerability of networks and neuronal populations, we focus here on what is known about selective vulnerability-related factors that might explain the differential phenotypic expressions of the same disease-in this case, typical and atypical forms of Alzheimer's disease. Whereas considerable progress has been made in this area, much is yet to be elucidated; further studies comparing different phenotypic variants aimed at identifying both vulnerability and resilience factors may provide valuable insights into disease pathogenesis, and suggest novel targets for therapy.
|
|
| 68. |
- Najar, Jenna, et al.
(författare)
-
Polygenic risk scores for Alzheimer's disease are related to dementia risk in APOE ɛ4 negatives.
- 2021
-
Ingår i: Alzheimer's & dementia (Amsterdam, Netherlands). - : Wiley. - 2352-8729. ; 13:1
-
Tidskriftsartikel (refereegranskat)abstract
- Studies examining the effect of polygenic risk scores (PRS) for Alzheimer's disease (AD) and apolipoprotein E (APOE) genotype on incident dementia in very old individuals are lacking.A population-based sample of 2052 individuals ages 70 to 111, from Sweden, was followed in relation to dementia. AD-PRSs including 39, 57, 1333, and 13,942 single nucleotide polymorphisms (SNPs) were used.AD-PRSs (including 39 or 57 SNPs) were associated with dementia (57-SNPs AD-PRS: hazard ratio 1.09, confidence interval 1.01-1.19, P=.03), particularly in APOE ɛ4 non-carriers (57-SNPs AD-PRS: 1.15, 1.05-1.27, P=4 × 10-3, 39-SNPs AD-PRS: 1.22, 1.10-1.35, P=2 × 10-4). No association was found with the other AD-PRSs. Further, APOE ɛ4 was associated with increased risk of dementia (1.60, 1.35-1.92, P=1 × 10-7). In those aged ≥95 years, the results were similar for the AD-PRSs, while APOE ɛ4 only predicted dementia in the low-risk tertile of AD-PRSs.These results provide information to identify individuals at increased risk of dementia.
|
|
| 69. |
- O'Connor, Yvonne, et al.
(författare)
-
The Importance of Form Field Validation : Lesson Learnt From a Feasibility Study of an M-Health Application in Malawi, Africa
- 2016
-
Ingår i: Pacific Asia Conference on Information Systems Proceedings. - : Association for Information Systems. - 9789860491029
-
Konferensbidrag (refereegranskat)abstract
- Measuring adherence to clinical guidelines using mobile health (mHealth) technologies when form field validation is enforced or turned on could potentially be viewed as skewing the dataset, leading to 100% adherence to the clinical rule base. In theory, healthcare providers should fully abide by clinical guidelines, whether in paper or digital format, to ensure that the patient receives appropriate care. However, what happens when mHealth form fieldvalidation is turned off? As part of a feasibility study in Malawi, Africa, we explored this phenomenon. Switching off validation on the mHealthartefact served its purpose within the context of a feasibility study where a parallel paper-based clinical assessment process remained in place. The design of this technical artefact with the turnkey validation feature afforded us the opportunity to turn validation on and off seamlessly. Ultimately, from an ethical, clinical and technical perspective the optimum approach is to ensurethat form field validation is switched on. With form field validation on adherence to the clinical guidelines is enforced which minimises incomplete assessment and the potential for suboptimal clinical decisions that could adversely affect patient care.
|
|
| 70. |
- Peuralinna, Terhi, et al.
(författare)
-
Neurofibrillary tau pathology modulated by genetic variation of alpha-synuclein
- 2008
-
Ingår i: Annals of Neurology. - : Wiley. - 0364-5134 .- 1531-8249. ; 64:3, s. 348-352
-
Tidskriftsartikel (refereegranskat)abstract
- We analyzed whether genetic variation of alpha-synuclein modulates the extent of neuropathological changes in a population-based autopsied sample of 272 elderly Finns. None of the 11 markers was associated with the extent of neocortical beta-amyloid pathology. The intron 4 marker rs2572324 was associated with the extent of neurofibrillary pathology (p = 0.0006, permuted p = 0.004; Braak stages IV-VI vs 0-II). The same variant also showed a trend for association with neocortical Lewy-related pathology. These results suggest for the first time that variation of alpha-synuclein modulates neurofibrillary tau pathology and support the recent observations of an interaction of alpha-synuclein and tau in neurodegeneration.
|
|
