Cerebral glucose deprivation linked to cognitive deficits, tau neuropathy & synaptic dysfunction

Insights and discussion from the cutting edge with reference to journal articles and other research papers.
Post Reply
User avatar
Julie G
Mod
Mod
Posts: 9193
Joined: Sat Oct 26, 2013 6:36 pm

Cerebral glucose deprivation linked to cognitive deficits, tau neuropathy & synaptic dysfunction

Post by Julie G »

Another rodent study ;). This is the first to directly link cerebral glucose hypometabolism to cognitive deficits, tau neuropathy & synaptic dysfunction. This is of particular importance to our genotype as E4 carriers (in a dose dependent fashion) exhibit decrease glucose utilization as early as ups 20s and 30s. Here's the press release:

Glucose deprivation in the brain sets stage for Alzheimer's disease, study shows
https://medicalxpress.com/news/2017-01- ... eimer.html

Here's the paper with full-text.

Glucose deficit triggers tau pathology and synaptic dysfunction in a tauopathy mouse model
http://www.nature.com/tp/journal/v7/n1/ ... 6296a.html
Abstract:
Clinical investigations have highlighted a biological link between reduced brain glucose metabolism and Alzheimer’s disease (AD). Previous studies showed that glucose deprivation may influence amyloid beta formation in vivo but no data are available on the effect that this condition might have on tau protein metabolism. In the current paper, we investigated the effect of glucose deficit on tau phosphorylation, memory and learning, and synaptic function in a transgenic mouse model of tauopathy, the h-tau mice. Compared with controls, h-tau mice with brain glucose deficit showed significant memory impairments, reduction of synaptic long-term potentiation, increased tau phosphorylation, which was mediated by the activation of P38 MAPK Kinase pathway. We believe our studies demonstrate for the first time that reduced glucose availability in the central nervous system directly triggers behavioral deficits by promoting the development of tau neuropathology and synaptic dysfunction. Since restoring brain glucose levels and metabolism could afford the opportunity to positively influence the entire AD phenotype, this approach should be considered as a novel and viable therapy for preventing and/or halting the disease progression. [Emphasis mine.]
MAC
Senior Contributor
Senior Contributor
Posts: 329
Joined: Mon Aug 29, 2016 2:24 pm

Re: Cerebral glucose deprivation linked to cognitive deficits, tau neuropathy & synaptic dysfunction

Post by MAC »

Is this your way of engaging us in "mental activities" Julie...these papers are very technical, difficult reads for us laypeople. :)

Very interesting and exciting root cause work..taking h-tau mice (designed to express only human tau) and injecting them with 2-deoxyglucose (DG), inducing tau phosphorylation, and correlating to cognitive decline.

https://en.wikipedia.org/wiki/2-Deoxy-D-glucose

2-Deoxy-D-glucose is a glucose molecule which has the 2-hydroxyl group replaced by hydrogen, so that it cannot undergo further glycolysis. As such, it acts to competitively inhibit the production of glucose-6-PO4 from glucose at the phosphoglucoisomerase level. DG competitively inhibits glucose cellular uptake since it uses the same system to enter the cell, the glucose transporters (that is, GLUTs). Once inside the cell, DG is quickly phosphorylated to form DG-6-phosphate which cannot be further metabolized via the glycolytic pathway and starts accumulating. This event by inhibiting cellular glycolysis at the initial step ultimately results in intra-cellular glucose deprivation.

The prevailing consensus is that NFT/TAU is a much more highly correlated pathway to cognitive decline in humans than Aβ burden. Might also help explain the failure of Aβ drug therapies to date.

Alzheimer disease therapy—moving from amyloid-β to tau
http://www.nature.com/nrneurol/journal/ ... 13.223.pdf

However, this study is still mice, not humans. Extensive experience from studies of anti-amyloid therapies has demonstrated that positive effects seen in animal models are rarely paralleled by similar success in patients with AD.

The correlation between HbA1c and cognitive decline is relatively very weak, as HbA1c measures plasma glycation only.

Glucose regulation, cognition, and brain MRI in type 2 diabetes: a systematic review
https://www.ncbi.nlm.nih.gov/pubmed/25163604

The glucose dysregulation in the brain is still a theory...whether it's causative/presymptomatic, or the brain responding to stress. Is it all related to IR? However, Cunnane*, as we know believes it's possibility causative. "Pre-symptomatic brain glucose hypometabolism isn’t necessarily the cause of AD or even the first step in the pathogenesis of AD, however, there are multiple examples of conditions in which the risk of AD is elevated and in which the regional brain glucose hypometabolism is present before the clinical (cognitive) onset of the disease. Examples of conditions in which regional brain glucose hypometabolism is present pre-symptomatically include carriers of the Pre-senilin-1 mutation, carriers of apolipoprotein E4, maternal family history of AD, cognitively healthy aging, and insulin resistance in both young and older persons"

* https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4937039/
MAC
E3/E4-59/MALE
Post Reply