scholarly journals Reduced coupling between cerebrospinal fluid flow and global brain activity is linked to Alzheimer disease–related pathology

PLoS Biology ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. e3001233
Author(s):  
Feng Han ◽  
Jing Chen ◽  
Aaron Belkin-Rosen ◽  
Yameng Gu ◽  
Liying Luo ◽  
...  

The glymphatic system plays an important role in clearing the amyloid-β (Aβ) and tau proteins that are closely linked to Alzheimer disease (AD) pathology. Glymphatic clearance, as well as Aβ accumulation, is highly dependent on sleep, but the sleep-dependent driving forces behind cerebrospinal fluid (CSF) movements essential to the glymphatic flux remain largely unclear. Recent studies have reported that widespread, high-amplitude spontaneous brain activations in the drowsy state and during sleep, which are shown as large global signal peaks in resting-state functional magnetic resonance imaging (rsfMRI), are coupled with CSF movements, suggesting their potential link to glymphatic flux and metabolite clearance. By analyzing multimodal data from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) project, here we showed that the coupling between the global fMRI signal and CSF influx is correlated with AD-related pathology, including various risk factors for AD, the severity of AD-related diseases, the cortical Aβ level, and cognitive decline over a 2-year follow-up. These results provide critical initial evidence for involvement of sleep-dependent global brain activity, as well as the associated physiological modulations, in the clearance of AD-related brain waste.

2020 ◽  
Author(s):  
Feng Han ◽  
Jing Chen ◽  
Aaron Belkin-Rosen ◽  
Yameng Gu ◽  
Liying Luo ◽  
...  

AbstractThe glymphatic system plays an important role in clearing the amyloid-β and tau proteins that are closely linked to Alzheimer’s disease (AD) pathology. Glymphatic clearance, as well as amyloid-β accumulation, is highly dependent on sleep, but the sleep-dependent driving forces behind cerebrospinal fluid (CSF) movements essential to the glymphatic flux remain largely unclear. Recent studies have reported that widespread, high-amplitude spontaneous brain activations in the drowsy state and during sleep, which are shown as large global signal peaks in resting-state fMRI, is coupled with the CSF movements, suggesting their potential link to the glymphatic flux and metabolite clearance. By analyzing multimodal data from the Alzheimer’s Disease Neuroimaging Initiative project, here we showed that the coupling between the global fMRI signal and CSF influx is correlated with AD-related pathology, including various risk factors for AD, the severity of AD-related diseases, the cortical amyloid-β level, and the cognitive decline over a two-year follow-up. These results provide critical initial evidence for involvement of sleep-dependent global brain activity, as well as the associated physiological modulations, in the clearance of AD-related brain waste.


2021 ◽  
Author(s):  
Feng Han ◽  
Gregory L. Brown ◽  
Yalin Zhu ◽  
Aaron E. Belkin‐Rosen ◽  
Mechelle M. Lewis ◽  
...  

2021 ◽  
pp. 1-8
Author(s):  
Paul Theo Zebhauser ◽  
Achim Berthele ◽  
Marie-Sophie Franz ◽  
Oliver Goldhardt ◽  
Janine Diehl-Schmid ◽  
...  

Background: Tau proteins are established biomarkers of neuroaxonal damage in a wide range of neurodegenerative conditions. Although measurement of total-Tau in the cerebrospinal fluid is widely used in research and clinical settings, the relationship between age and total-Tau in the cerebrospinal fluid is yet to be fully understood. While past studies reported a correlation between age and total-Tau in the cerebrospinal fluid of healthy adults, in clinical practice the same cut-off value is used independently of patient’s age. Objective: To further explore the relationship between age and total-Tau and to disentangle neurodegenerative from drainage-dependent effects. Methods: We analyzed cerebrospinal fluid samples of 76 carefully selected cognitively healthy adults and included amyloid-β 1–40 as a potential marker of drainage from the brain’s interstitial system. Results: We found a significant correlation of total-Tau and age, which was no longer present when correcting total-Tau for amyloid-β 1–40 concentrations. These findings were replicated under varied inclusion criteria. Conclusion: Results call into question the association of age and total-Tau in the cerebrospinal fluid. Furthermore, they suggest diagnostic utility of amyloid-β 1–40 as a possible proxy for drainage-mechanisms into the cerebrospinal fluid when interpreting biomarker concentrations for neurodegenerative diseases.


2020 ◽  
pp. 1-24
Author(s):  
Conrad N. Trumbore

Amyloid-β (Aβ) and tau oligomers have been identified as neurotoxic agents responsible for causing Alzheimer’s disease (AD). Clinical trials using Aβ and tau as targets have failed, giving rise to calls for new research approaches to combat AD. This paper provides such an approach. Most basic AD research has involved quiescent Aβ and tau solutions. However, studies involving laminar and extensional flow of proteins have demonstrated that mechanical agitation of proteins induces or accelerates protein aggregation. Recent MRI brain studies have revealed high energy, chaotic motion of cerebrospinal fluid (CSF) in lower brain and brainstem regions. These and studies showing CSF flow within the brain have shown that there are two energetic hot spots. These are within the third and fourth brain ventricles and in the neighborhood of the circle of Willis blood vessel region. These two regions are also the same locations as those of the earliest Aβ and tau AD pathology. In this paper, it is proposed that cardiac systolic pulse waves that emanate from the major brain arteries in the lower brain and brainstem regions and whose pulse waves drive CSF flows within the brain are responsible for initiating AD and possibly other amyloid diseases. It is further proposed that the triggering of these diseases comes about because of the strengthening of systolic pulses due to major artery hardening that generates intense CSF extensional flow stress. Such stress provides the activation energy needed to induce conformational changes of both Aβ and tau within the lower brain and brainstem region, producing unique neurotoxic oligomer molecule conformations that induce AD.


2006 ◽  
Vol 52 (2) ◽  
pp. 332-334 ◽  
Author(s):  
Piotr Lewczuk ◽  
Georg Beck ◽  
Hermann Esselmann ◽  
Ralf Bruckmoser ◽  
Rüdiger Zimmermann ◽  
...  

2000 ◽  
Vol 57 (1) ◽  
pp. 100 ◽  
Author(s):  
Pankaj D. Mehta ◽  
Tuula Pirttilä ◽  
Sangita P. Mehta ◽  
Eugene A. Sersen ◽  
Paul S. Aisen ◽  
...  

2021 ◽  
pp. 1-10
Author(s):  
Ya-Hui Ma ◽  
Ya-Yu Wang ◽  
Lan Tan ◽  
Wei Xu ◽  
Xue-Ning Shen ◽  
...  

Background: Although social networks are deemed as moderators of incident Alzheimer’s disease (AD), few data are available on the mechanism relevant to AD pathology. Objective: We aimed to investigate whether social networks affect metabolism of cerebrospinal fluid (CSF) AD biomarkers during early stage and identify modification effects of genetic factor and subjective cognitive decline (SCD). Methods: We studied participants from the Chinese Alzheimer’s disease Biomarker and Lifestyle (CABLE) database who received cognition assessments and CSF amyloid-β (Aβ 1–42 and Aβ 1–40) and tau proteins (total-tau [T-tau] and phosphorylated-tau [P-tau]) measurements. The social networks were measured using self-reported questionnaires about social ties. Linear regression models were used. Results: Data were analyzed from 886 cognitively intact individuals aged 61.91 years (SD = 10.51), including 295 preclinical AD participants and 591 healthy controls. Social networks were mostly associated with CSF indicators of AD multi-pathologies (low P-tau/Aβ 1–42 and T-tau/Aβ 1–42 and high Aβ 1–42/Aβ 1–40). Significant differences of genetic and cognitive status were observed for CSF indicators, in which associations of social network scores with CSF P-tau and indicators of multi-pathologies appeared stronger in APOE 4 carriers (versus non-carriers) and participants with SCD (versus controls), respectively. Alternatively, more pronounced associations for CSF T-tau (β= –0.005, p <  0.001), Aβ 1–42/Aβ 1–40 (β= 0.481, p = 0.001), and T-tau/Aβ 1–42 (β= –0.047, p <  0.001) were noted in preclinical AD stage than controls. Conclusion: These findings consolidated strong links between social networks and AD risks. Social networks as a modifiable lifestyle probably affected metabolisms of multiple AD pathologies, especially among at-risk populations.


2001 ◽  
Vol 304 (1-2) ◽  
pp. 102-106 ◽  
Author(s):  
P.D Mehta ◽  
T Pirttila ◽  
B.A Patrick ◽  
M Barshatzky ◽  
S.P Mehta

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