| 1. |
- Li, Shu-Chen, et al.
(författare)
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Aging magnifies the effects of dopamine transporter and D2 receptor genes on backward serial memory
- 2013
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 34:1, s. 358.e1-358.e10
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Tidskriftsartikel (refereegranskat)abstract
- Aging compromises dopamine transporter (DAT) and receptor mechanisms in the frontostriatal circuitry. In a sample of 1288 younger and older adults, we investigated (i) whether individual differences in genotypes of the DAT gene (i.e., SLC6A3, the DAT variable number of tandem repeat 9/9, 9/10, and 10/10) and in the D2 receptor (DRD2) gene (i.e., the C957T [rs6277] CC and any T) interactively contribute to phenotype variations in episodic memory performance; and (ii) whether these genetic effects are magnified in older adults, because of considerable declines in the dopamine functions. Our results showed that carrying genotypes associated with higher levels of striatal synaptic dopamine (DAT 9/9) and higher density of extrastriatal D2 receptors (C957T CC) were associated with better backward serial recall, an episodic memory task with high encoding and retrieval demands. Critically, the gene-gene interaction effect was reliably stronger in older than in younger adults. In line with the resource modulation hypothesis, our findings suggest that aging-related decline in brain phenotypes (e.g., dopamine functions) could alter the relations between genotypes and behavioral phenotypes (e.g., episodic memory).
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| 2. |
- Nilsson, Lars-Göran, 1944-, et al.
(författare)
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Challenging the notion of an early-onset of cognitive decline.
- 2009
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Ingår i: Neurobiology of Aging. - : Elsevier. - 0197-4580 .- 1558-1497. ; 30:4, s. 521-524; discussion 530
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Salthouse claims that cognitive aging starts around 20 years of age. The basis for this claim is cross-sectional data. He dismisses longitudinal data, which typically show the cognitive decline to start much later, around 60 years of age. He states that longitudinal data cannot be trusted because they are flawed. There is a confounding between the effects of maturation and retest effects. We challenge Salthouse's strong claim on four accounts.
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| 3. |
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| 4. |
- Bäckman, Lars, et al.
(författare)
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Dopamine D(1) receptors and age differences in brain activation during working memory
- 2011
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Ingår i: Neurobiology of Aging. - Fayetteville, N.Y : Elsevier. - 0197-4580 .- 1558-1497. ; 32:10, s. 1849-1856
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Tidskriftsartikel (refereegranskat)abstract
- In an fMRI study, 20 younger and 20 healthy older adults were scanned while performing a spatial working-memory task under two levels of load. On a separate occasion, the same subjects underwent PET measurements using the radioligand [(11)C] SCH23390 to determine dopamine D(1) receptor binding potential (BP) in caudate nucleus and dorsolateral prefrontal cortex (DLPFC). The fMRI study revealed a significant load modulation of brain activity (higher load>lower load) in frontal and parietal regions for younger, but not older, adults. The PET measurements showed marked age-related reductions of D(1) BP in caudate and DLPFC. Statistical control of caudate and DLPFC D(1) binding eliminated the age-related reduction in load-dependent BOLD signal in left frontal cortex, and attenuated greatly the reduction in right frontal and left parietal cortex. These findings suggest that age-related alterations in dopaminergic neurotransmission may contribute to underrecruitment of task-relevant brain regions during working-memory performance in old age.
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| 5. |
- Darreh-Shori, Taher, et al.
(författare)
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Differential levels of apolipoprotein E and butyrylcholinesterase show strong association with pathological signs of Alzheimer's disease in the brain in vivo
- 2011
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Ingår i: Neurobiology of Aging. - : Elsevier. - 0197-4580 .- 1558-1497. ; 32:12, s. 2320.e15-2320.e32
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Tidskriftsartikel (refereegranskat)abstract
- Recently, we reported that 3 of the known risk factors of Alzheimer's disease (AD), i.e., advanced age, apolipoprotein E (ApoE) ε4, and female gender, are associated with differential levels of ApoE proteins and butyrylcholinesterase (BuChE) in the cerebrospinal fluid (CSF) of AD patients. The ApoE ε4 allele and certain BuChE polymorphisms synergistically affect the conversion rate of mild cognitive impairment (MCI) to AD. Here, we investigated interrelationships between ApoE and BuChE levels, and pathological markers of AD in vivo. CSF from patients with probable AD, assessed for cerebral glucose metabolism (CMRglc; n = 50) and Pittsburgh compound B (PIB) retention (β-amyloid [Aβ] load, n = 29) by positron emission tomography (PET), was used for measurement of BuChE, ApoE, Aβ, tau, phosphorylated tau (P-tau) and interleukin-1β (IL-1β) levels. Levels of ApoE and BuChE strongly correlated with CMRglc (fluorodeoxyglucose [FDG]-PET, r = 0.54, p < 0.0001, n = 50), cerebral Aβ load (PIB retention, r = 0.73, p < 0.0001, n = 29), and CSF P-tau (r = 0.73, p < 0.0001, n = 33). High ApoE protein was tied to low CMRglc and high PIB retention and P-tau. BuChE levels had opposite relationships. Other CSF covariates were levels of interleukin-1β and Aβ42peptide. The pattern of the patients' cognitive Z-scores strongly supported these observations. High ApoE protein was also linked to changes in 3 of the biodynamic properties of BuChE. In vitro analysis indicated that high ApoE protein levels were related to an increased pool of dormant BuChE molecules with an abnormally high intrinsic catalytic rate in CSF, which was “turned on” by excess Aβ peptides. The findings suggest that abnormally high levels of ApoE may play a causative role in the pathological events of AD, particularly those involving the early cholinergic deficit in the AD brain, through modulation of cholinesterases activities, hence disturbing the acetylcholine-dependent activity of neurons and nonexcitable cells such as glial cells.
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| 6. |
- Darreh-Shori, Taher, et al.
(författare)
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Functional variability in butyrylcholinesterase activity regulates intrathecal cytokine and astroglial biomarker profiles in patients with Alzheimer's disease
- 2013
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 34:11, s. 2465-2481
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Tidskriftsartikel (refereegranskat)abstract
- Butyrylcholinesterase (BuChE) activity is associated with activated astrocytes in Alzheimer's disease brain. The BuChE-K variant exhibits 30%-60% reduced acetylcholine (ACh) hydrolyzing capacity. Considering the increasing evidence of an immune-regulatory role of ACh, we investigated if genetic heterogeneity in BuChE affects cerebrospinal fluid (CSF) biomarkers of inflammation and cholinoceptive glial function. Alzheimer's disease patients (n = 179) were BCHE-K-genotyped. Proteomic and enzymatic analyses were performed on CSF and/or plasma. BuChE genotype was linked with differential CSF levels of glial fibrillary acidic protein, S100B, interleukin-1 beta, and tumor necrosis factor (TNF)-alpha. BCHE-K noncarriers displayed 100%-150% higher glial fibrillary acidic protein and 64%-110% higher S100B than BCHE-K carriers, who, in contrast, had 40%-80% higher interleukin-1b and 21%-27% higher TNF-alpha compared with noncarriers. A high level of CSF BuChE enzymatic phenotype also significantly correlated with higher CSF levels of astroglial markers and several factors of the innate complement system, but lower levels of proinflammatory cytokines. These individuals also displayed beneficial paraclinical and clinical findings, such as high cerebral glucose utilization, low beta-amyloid load, and less severe progression of clinical symptoms. In vitro analysis on human astrocytes confirmed the involvement of a regulated BuChE status in the astroglial responses to TNF-alpha and ACh. Histochemical analysis in a rat model of nerve injury-induced neuroinflammation, showed focal assembly of astroglial cells in proximity of BuChE-immunolabeled sites. In conclusion, these results suggest that BuChE enzymatic activity plays an important role in regulating intrinsic inflammation and activity of cholinoceptive glial cells and that this might be of clinical relevance. The dissociation between astroglial markers and inflammatory cytokines indicates that a proper activation and maintenance of astroglial function is a beneficial response, rather than a disease-driving mechanism. Further studies are needed to explore the therapeutic potential of manipulating BuChE activity or astroglial functional status. (C) 2013 Elsevier Inc. All rights reserved.
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| 7. |
- Forsberg, Anton, et al.
(författare)
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PET imaging of amyloid deposition in patients with mild cognitive impairment
- 2008
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 29:10, s. 1456-1465
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Tidskriftsartikel (refereegranskat)abstract
- It is of great clinical value to identify subjects at a high risk of developing AD. We previously found that the amyloid positron emission tomography (PET) tracer PIB showed a robust difference in retention in the brain between AD patients and healthy controls (HC). Twenty-one patients diagnosed with MCI (mean age 63.3 ± 7.8 (S.D.) years) underwent PET studies with 11C-PIB, and 18F-fluoro-deoxy-glucose (FDG) to measure cerebral glucose metabolism, as well as assessment of cognitive function and CSF sampling. Reference group data from 27 AD patients and 6 healthy controls, respectively, were used for comparison. The mean cortical PIB retention for the MCI patients was intermediate compared to HC and AD. Seven MCI patients that later at clinical follow-up converted to AD (8.1 ± 6.0 (S.D.) months) showed significant higher PIB retention compared to non-converting MCI patients and HC, respectively (ps < 0.01). The PIB retention in MCI converters was comparable to AD patients (p > 0.01). Correlations were observed in the MCI patients between PIB retention and CSF Aβ1-42, total Tau and episodic memory, respectively.
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| 8. |
- Hansson, Oskar, et al.
(författare)
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Combined rCBF and CSF biomarkers predict progression from mild cognitive impairment to Alzheimer's disease.
- 2009
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Ingår i: Neurobiology of aging. - : Elsevier BV. - 1558-1497 .- 0197-4580. ; 30:2, s. 165-73
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Tidskriftsartikel (refereegranskat)abstract
- This study aimed to identify preclinical Alzheimer's disease (AD) in patients with mild cognitive impairment (MCI) using measurements of both regional cerebral blood flow (rCBF) and cerebrospinal fluid (CSF) biomarkers. Baseline rCBF assessments ((133)Xe method) were performed in 70 patients with MCI who were cognitively stable for 4-6 years, 69 patients with MCI who subsequently developed AD, and 33 healthy individuals. CSF was collected at baseline and analyzed for beta-amyloid(1-42), total tau and phophorylated tau. In contrast to patients with stable MCI, those who subsequently developed AD had decreased rCBF in the temporo-parietal cortex already at baseline. The relative risk of future progression to AD was particularly increased in MCI patients with decreased rCBF in parietal cortex (hazard ratio 3.1, P<0.0001). Subjects with pathological levels of both CSF tau and beta-amyloid(1-42) were also at high risk of developing AD (hazard ratio 13.4, P<0.0001). The MCI patients with a combination of decreased parietal rCBF and pathological CSF biomarkers at baseline had a substantially increased risk of future development of AD, with a hazard ratio of 24.3 (P<0.0001), when compared to those with normal CSF biomarkers. Moreover, decreased parietal rCBF (but not CSF biomarkers) was associated with a more rapid progression to AD. In conclusion, the combination of rCBF and CSF biomarkers improves the risk assessment of progression to AD in patients with MCI.
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| 9. |
- Horta, Marilyn, et al.
(författare)
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Oxytocin alters patterns of brain activity and amygdalar connectivity by age during dynamic facial emotion identification
- 2019
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Ingår i: Neurobiology of Aging. - : Elsevier. - 0197-4580 .- 1558-1497. ; 78, s. 42-51
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Tidskriftsartikel (refereegranskat)abstract
- Aging is associated with increased difficulty in facial emotion identification, possibly due to age-related network change. The neuropeptide oxytocin (OT) facilitates emotion identification, but this is understudied in aging. To determine the effects of OT on dynamic facial emotion identification across adulthood, 46 young and 48 older participants self-administered intranasal OT or a placebo in a randomized, double-blind procedure. Older participants were slower and less accurate in identifying emotions. Although there was no behavioral treatment effect, partial least squares analysis supported treatment effects on brain patterns during emotion identification that varied by age and emotion. For young participants, OT altered the processing of sadness and happiness, whereas for older participants, OT only affected the processing of sadness (15.3% covariance, p = 0.004). Furthermore, seed partial least squares analysis showed that older participants in the OT group recruited a large-scale amygdalar network that was positively correlated for anger, fear, and happiness, whereas older participants in the placebo group recruited a smaller, negatively correlated network (7% covariance, p = 0.002). Advancing the literature, these findings show that OT alters brain activity and amygdalar connectivity by age and emotion.
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| 10. |
- Janciauskiene, Sabina, et al.
(författare)
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A link between sICAM-1, ACE and parietal blood flow in the aging brain.
- 2009
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 30:9, s. 1504-1511
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Tidskriftsartikel (refereegranskat)abstract
- A connection between Alzheimer's disease (AD) and endothelium pathology has been inferred from measured decreases in both blood flow and metabolism in the parietal and temporal cortex. However, it is not known whether these alterations are seen in normal aging. We performed regional cerebral blood flow (rCBF) measurements in 22 AD patients and in 44 non-demented subjects during a simple test of information processing speed. Cerebrospinal fluid (CSF) levels of angiotensin-converting enzyme (ACE) and the soluble form of intercellular adhesion molecule-1 (sICAM-1) were analyzed in non-demented subjects. We found correlations between sICAM-1 and ACE (p=0.004), and sICAM (but not ACE) and CSF/plasma albumin ratio (p<0.0001). Higher concentrations of sICAM-1 (>893ng/L) and ACE (>5.22microg/L) were exclusively associated with lower parietal blood flow (p<0.001). The rCBF patterns in the AD and non-demented subjects with biomarker levels above median showed similar reductions in the temporoparietal areas. Our findings provide evidence that elevated CSF sICAM-1 and ACE are associated with lower perfusion levels in the parietal cortex of cognitively intact elderly.
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