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32 Elevated Plasma pTau-181 is Associated with Lower Global Cognition and Executive Function in Older Adults
- Arunima Kapoor, Jean K Ho, Shubir Dutt, Yanrong Li, John P Alitin, Jung Yun Jang, Aimee Gaubert, Amy Nguyen, Belinda Yew, Anna E Blanken, Isabel J Sible, Anisa Marshall, Fatemah Shenasa, Alessandra Martini, Kathleen E Rodgers, Elizabeth Head, Daniel A Nation
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 907-908
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Objective:
Aggregation of phosphorylated tau (pTau) is a hallmark feature of Alzheimer’s disease (AD). Novel assays now allow pTau to be measured in plasma. Elevated plasma pTau predicts subsequent development of AD, cortical atrophy and AD-related pathologies in the brain. We aimed to determine whether elevated pTau is associated with cognitive functioning in older adults prior to the development of dementia.
Participants and Methods:Independently living older adults (N = 48, mean age = 70.0 years; SD = 7.7; age range 55-88 years; 35.4% male) free of dementia or clinical stroke were recruited from the community and underwent blood draw and neuropsychological assessment. Plasma was assayed using the Quanterix Simoa® pTau-181 V2 Advantage Kit to quantify pTau-181 levels and APOE genotyping was conducted on the blood cell pellet fraction obtained from plasma separation. Global cognition was assessed using the Dementia Rating Scale-2 (DRS-2) and executive function was assessed using the Stroop, D-KEFS-2 Fluency, and Trails Making Test. Diagnosis of mild cognitive impairment (MCI) was determined based on overall neuropsychological performance. Participants were diagnosed as MCI if they scored >1 SD below norm-referenced values on 2 or more tests within a domain (language, executive, memory) or on 3 tests across domains.
Results:Multiple linear regression analysis revealed a significant negative association between plasma pTau-181 levels and DRS-2 (B = -2.57, 95% CI (-3.68, -1.47), p <.001), Stroop Color-Word score (B = -2.64, 95% CI (-4.56, - 0.71), p = .009) and Fruits and Vegetables Fluency (B = -1.67, 95% CI (-2.84, -0.49), p = .007), adjusting for age, sex, education and APOE4 status. MCI diagnosis was determined for 43 participants, of which 8 (18.6%) met criteria. Logistic regression analysis revealed that pTau-181 levels are associated with increased odds of MCI diagnosis (OR = 2.18, 95% CI (1.01, 4.68), p = .046), after accounting for age, sex, education and APOE4 status.
Conclusions:Elevated plasma pTau-181 is associated with worse cognition, particularly executive function, and predicts MCI diagnosis in older adults. Higher plasma pTau-181 was associated with increased odds of MCI diagnosis. Detection of pTau-181 in plasma allows a novel, non-invasive method to detect burden of one form of AD pathology. These findings lend support to the use of plasma pTau-181 as a valuable marker in detecting even early cognitive changes prior to the development of AD. Additional longitudinal studies are warranted to explore the prognostic value of plasma pTau-181 over time.
96 Short-Term Blood Pressure Variability and Cerebrovascular Health in OlderaAdults
- Isabel J Sible, Belinda Yew, Arunima Kapoor, Jung Y Jang, John Paul M Alitin, Shubir Dutt, Yanrong Li, Anna E Blanken, Jean K Ho, Anisa J Marshall, Fatemah Shenasa, Aimee Gaubert, Amy Nguyen, Kathleen E Rodgers, Virginia E Sturm, Daniel A Nation
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 195-196
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Objective:
Blood pressure variability (BPV), independent of traditionally targeted average blood pressure levels, is an emerging vascular risk factor for stroke, cerebrovascular disease, and dementia, possibly through links with vascular-endothelial injury. Recent evidence suggests visit-to-visit (e.g., over months, years) BPV is associated with cerebrovascular disease severity, but less is known about relationships with short-term (e.g., < 24 hours) fluctuations in blood pressure. Additionally, it is unclear how BPV may be related to angiogenic growth factors that play a role in cerebral arterial health.
Participants and Methods:We investigated relationships between short-term BPV, white matter hyperintensities on MRI, and levels of plasma vascular endothelial growth factor (VEGF) in a sample of community-dwelling older adults (n = 57, ages 55-88) without history of dementia or stroke. Blood pressure was collected continuously during a 5-minute resting period. BPV was calculated as variability independent of mean, a commonly used index of BPV uncorrelated with average blood pressure levels. Participants underwent T2-FLAIR MRI to determine severity of white matter lesion burden. Severity of lesions was classified as Fazekas scores (0-3). Participants also underwent venipuncture to determine levels of plasma VEGF. Ordinal logistic regression examined the association between BPV and Fazekas scores. Multiple linear regression explored relationships between BPV and VEGF. Models controlled for age, sex, and average blood pressure.
Results:Elevated BPV was related to greater white matter lesion burden (i.e., Fazekas score) (systolic: OR = 1.17 [95% CI 1.01, 1.37]; p = .04; diastolic: OR = 2.47 [95% CI 1.09, 5.90]; p = .03) and increased levels of plasma VEGF (systolic: ß = .39 [95% CI .11, .67]; adjusted R2 = .16; p = .007; diastolic: ß = .48 [95% CI .18, .78]; adjusted R2 = .18; p = .003).
Conclusions:Findings suggest short-term BPV may be related to cerebrovascular disease burden and angiogenic growth factors relevant to cerebral arterial health, independent of average blood pressure. Understanding the role of BPV in cerebrovascular disease and vascular-endothelial health may help elucidate the increased risk for stroke and dementia associated with elevated BPV.
Trypanosomiasis and the brain
- JEAN RODGERS
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- Journal:
- Parasitology / Volume 137 / Issue 14 / December 2010
- Published online by Cambridge University Press:
- 23 December 2009, pp. 1995-2006
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Neurological involvement following trypanosome infection has been recognised for over a century. However, there are still many unanswered questions concerning the mechanisms used by the parasite to gain entry to the CNS and the pathogenesis of the resulting neuroinflammatory reaction. There is a paucity of material from human cases of the disease therefore the majority of current research relies on the use of animal models of trypanosome infection. This review reports contemporary knowledge, from both animal models and human samples, regarding parasite invasion of the CNS and the neuropathological changes that accompany trypanosome infection and disease progression. The effects of trypanosomes on the blood-brain barrier are discussed and possible key molecules in parasite penetration of the barrier highlighted. Changes in the balance of CNS cytokines and chemokines are also described. The article closes by summarising the effects of trypanosome infection on the circadian sleep-wake cycle, and sleep structure, in relation to neuroinflammation and parasite location within the CNS. Although a great deal of progress has been made in recent years, the advent and application of sophisticated analysis techniques, to decipher the complexities of HAT pathogenesis, herald an exciting and rewarding period for advances in trypanosome research.