scholarly journals Sleep fragmentation, microglial aging, and cognitive impairment in adults with and without Alzheimer’s dementia

2019 ◽  
Vol 5 (12) ◽  
pp. eaax7331 ◽  
Author(s):  
Kirusanthy Kaneshwaran ◽  
Marta Olah ◽  
Shinya Tasaki ◽  
Lei Yu ◽  
Elizabeth M. Bradshaw ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Older Persons ◽  
Microglial Activation ◽  
Marker Gene ◽  
Sleep Fragmentation ◽  
Sleep Disruption ◽  
Religious Orders ◽  
Marker Gene Expression ◽  
Expression Of Genes ◽  
Underlying Mechanisms

Sleep disruption is associated with cognitive decline and dementia in older adults; however, the underlying mechanisms are unclear. In rodents, sleep disruption causes microglial activation, inhibition of which improves cognition. However, data from humans are lacking. We studied participants in two cohort studies of older persons—the Rush Memory and Aging Project and the Religious Orders Study. We assessed sleep fragmentation by actigraphy and related this to cognitive function, to neocortical microglial marker gene expression measured by RNA sequencing, and to the neocortical density of microglia assessed by immunohistochemistry. Greater sleep fragmentation was associated with higher neocortical expression of genes characteristic of aged microglia, and a higher proportion of morphologically activated microglia, independent of chronological age- and dementia-related neuropathologies. Furthermore, these were, in turn, associated with worse cognition. This suggests that sleep fragmentation is accompanied by accelerated microglial aging and activation, which may partially underlie its association with cognitive impairment.

Inflammatory Pathways Are Impaired in Alzheimer Disease and Differentially Associated With Apolipoprotein E Status

2021 ◽  
Author(s):  
Courtney M Kloske ◽  
Adam J Dugan ◽  
Erica M Weekman ◽  
Zachary Winder ◽  
Ela Patel ◽  
...  
Keyword(s):  
Alzheimer Disease ◽  
Apolipoprotein E ◽  
Microglial Activation ◽  
Middle Temporal Gyrus ◽  
Altered Expression ◽  
Apoe Ε4 ◽  
Apoe Isoforms ◽  
Expression Of Genes ◽  
Underlying Mechanisms ◽  
The Brain

Abstract Alzheimer disease (AD) is a neurodegenerative disease characterized by a cognitive decline leading to dementia. The most impactful genetic risk factor is apolipoprotein E (APOE). APOE-ε4 significantly increases AD risk, APOE-ε3 is the most common gene variant, and APOE-ε2 protects against AD. However, the underlying mechanisms of APOE-ε4 on AD risk remains unclear, with APOE-ε4 impacting many pathways. We investigated how the APOE isoforms associated with the neuroinflammatory state of the brain with and without AD pathology. Frozen brain tissue from the superior and middle temporal gyrus was analyzed from APOE-ε3/3 (n = 9) or APOE-ε4/4 (n = 10) participants with AD pathology and APOE-ε3/3 (n = 9) participants without AD pathology. We determined transcript levels of 757 inflammatory related genes using the NanoString Human Neuroinflammation Panel. We found significant pathways impaired in APOE-ε4/4-AD individuals compared to APOE-ε3/3-AD. Of interest, expression of genes related to microglial activation (SALL1), motility (FSCN1), epigenetics (DNMT1), and others showed altered expression. Additionally, we performed immunohistochemistry of P2RY12 to confirm reduced microglial activation. Our results suggest APOE-ε3 responds to AD pathology while potentially having a harmful long-term inflammatory response, while APOE-ε4 shows a weakened response to pathology. Overall, APOE isoforms appear to modulate the brain immune response to AD-type pathology.

Physical activity and cognitive function in older persons

2016 ◽  
Vol 64 (2) ◽  
Keyword(s):  
Physical Activity ◽  
Cognitive Impairment ◽  
Cognitive Function ◽  
Executive Functions ◽  
Cognitive Aging ◽  
Clinical Studies ◽  
Older Persons ◽  
Positive Effects ◽  
Critical Challenge

Strategies to improve cognitive aging are highly needed. Among those, promotion of exercise and physical activity appears as one of the most attractive and beneficial intervention. Indeed, results from basic and clinical studies suggest that exercise and physical activity have positive effects on cognition in older persons without cognitive impairment, as well as in those with dementia. Despite inconsistent results, aerobic exercise appears to have the strongest potential to enhance cognition. However, even limited periods of walking (45 minutes, three times a week, over a 6-month period) have also been shown to enhance cognition, particularly executive functions. Changing long-term lifestyle habits in these older persons remains a critical challenge and attractive programs susceptible to gain adherence are needed to succeed in achieving improved cognitive aging.

Increasing Life-Space Mobility in Community-Dwelling Older Persons With Cognitive Impairment Following Rehabilitation: A Randomized Controlled Trial

2020 ◽  
Author(s):  
Phoebe Ullrich ◽  
Christian Werner ◽  
Martin Bongartz ◽  
Tobias Eckert ◽  
Bastian Abel ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Older Persons ◽  
Controlled Trial ◽  
Intervention Group ◽  
Community Dwelling ◽  
Control Group ◽  
Life Space ◽  
Home Based ◽  
Independent Life

Abstract Background Community-dwelling older persons with cognitive impairment (CI) following discharge from geriatric rehabilitation are at high risk of losing life-space mobility (LSM). Interventions to improve their LSM are, however, still lacking. The aim of this study was to evaluate the effects of a CI-specific, home-based physical training and activity promotion program on LSM. Methods Older persons with mild-to-moderate CI (Mini-Mental State Examination: 17–26 points) discharged home from rehabilitation were included in this double-blinded, randomized, placebo-controlled trial with a 12-week intervention period and 12-week follow-up period. The intervention group received a CI-specific, home-based strength, balance, and walking training supported by tailored motivational strategies. The control group received a placebo activity. LSM was evaluated by the Life-Space Assessment in Persons with Cognitive Impairment, including a composite score for LSM and 3 subscores for maximal, equipment-assisted, and independent life space. Mixed-model repeated-measures analyses were used. Results One hundred eighteen participants (82.3 ± 6.0 years) with CI (Mini-Mental State Examination: 23.3 ± 2.4) were randomized. After the intervention, the home-based training program resulted in a significant benefit in the Life-Space Assessment in Persons with Cognitive Impairment composite scores (b = 8.15; 95% confidence interval: 2.89–13.41; p = .003) and independent life-space subscores (b = 0.39; 95% confidence interval: 0.00–0.78; p = .048) in the intervention group (n = 63) compared to control group (n = 55). Other subscores and follow-up results were not significantly different. Conclusions The home-based training program improved LSM and independent life space significantly in this vulnerable population. Effects were not sustained over the follow-up. The program may represent a model for improved transition from rehabilitation to the community to prevent high risk of LSM restriction.

scholarly journals Intranasal insulin rescues repeated anesthesia-induced deficits in synaptic plasticity and memory and prevents apoptosis in neonatal mice via mTORC1

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Patricia Soriano Roque ◽  
Mehdi Hooshmandi ◽  
Laura Neagu-Lund ◽  
Shelly Yin ◽  
Noosha Yousefpour ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Synaptic Plasticity ◽  
General Anesthesia ◽  
Preventive Treatment ◽  
Intranasal Insulin ◽  
Translational Repressor ◽  
Beneficial Effects ◽  
Underlying Mechanisms ◽  
Induced Apoptosis ◽  
Preclinical And Clinical Studies

AbstractLong-lasting cognitive impairment in juveniles undergoing repeated general anesthesia has been observed in numerous preclinical and clinical studies, yet, the underlying mechanisms remain unknown and no preventive treatment is available. We found that daily intranasal insulin administration to juvenile mice for 7 days prior to repeated isoflurane anesthesia rescues deficits in hippocampus-dependent memory and synaptic plasticity in adulthood. Moreover, intranasal insulin prevented anesthesia-induced apoptosis of hippocampal cells, which is thought to underlie cognitive impairment. Inhibition of the mechanistic target of rapamycin complex 1 (mTORC1), a major intracellular effector of insulin receptor, blocked the beneficial effects of intranasal insulin on anesthesia-induced apoptosis. Consistent with this finding, mice lacking mTORC1 downstream translational repressor 4E-BP2 showed no induction of repeated anesthesia-induced apoptosis. Our study demonstrates that intranasal insulin prevents general anesthesia-induced apoptosis of hippocampal cells, and deficits in synaptic plasticity and memory, and suggests that the rescue effect is mediated via mTORC1/4E-BP2 signaling.

scholarly journals E3 ubiquitin ligase Grail promotes hepatic steatosis through Sirt1 inhibition

2021 ◽  
Vol 12 (4) ◽  
Author(s):  
Pei-Yao Liu ◽  
Cheng-Cheung Chen ◽  
Chia-Ying Chin ◽  
Te-Jung Liu ◽  
Wen-Chiuan Tsai ◽  
...  
Keyword(s):  
Hepatic Steatosis ◽  
Lipid Accumulation ◽  
Acid Synthesis ◽  
Sirtuin 1 ◽  
Nonalcoholic Fatty Liver ◽  
Expression Of Genes ◽  
Hepatic Fat ◽  
Underlying Mechanisms

AbstractIn obese adults, nonalcoholic fatty liver disease (NAFLD) is accompanied by multiple metabolic dysfunctions. Although upregulated hepatic fatty acid synthesis has been identified as a crucial mediator of NAFLD development, the underlying mechanisms are yet to be elucidated. In this study, we reported upregulated expression of gene related to anergy in lymphocytes (GRAIL) in the livers of humans and mice with hepatic steatosis. Grail ablation markedly alleviated the high-fat diet-induced hepatic fat accumulation and expression of genes related to the lipid metabolism, in vitro and in vivo. Conversely, overexpression of GRAIL exacerbated lipid accumulation and enhanced the expression of lipid metabolic genes in mice and liver cells. Our results demonstrated that Grail regulated the lipid accumulation in hepatic steatosis via interaction with sirtuin 1. Thus, Grail poses as a significant molecular regulator in the development of NAFLD.

scholarly journals Pharmacological rescue of cognitive function in a mouse model of chemobrain

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Lien D. Nguyen ◽  
Tom T. Fischer ◽  
Barbara E. Ehrlich
Keyword(s):  
Cognitive Impairment ◽  
Prefrontal Cortex ◽  
Calcium Oscillations ◽  
Neuronal Morphology ◽  
Post Injection ◽  
Object Recognition Test ◽  
Cognitive Changes ◽  
Memory Acquisition ◽  
Underlying Mechanisms ◽  
Trisphosphate Receptor

Abstract Background After chemotherapy, many cancer survivors suffer from long-lasting cognitive impairment, colloquially known as “chemobrain.” However, the trajectories of cognitive changes and the underlying mechanisms remain unclear. We previously established paclitaxel-induced inositol trisphosphate receptor (InsP3R)-dependent calcium oscillations as a mechanism for peripheral neuropathy, which was prevented by lithium pretreatment. Here, we investigated if a similar mechanism also underlay paclitaxel-induced chemobrain. Method Mice were injected with 4 doses of 20 mg/kg paclitaxel every other day to induced cognitive impairment. Memory acquisition was assessed with the displaced object recognition test. The morphology of neurons in the prefrontal cortex and the hippocampus was analyzed using Golgi-Cox staining, followed by Sholl analyses. Changes in protein expression were measured by Western blot. Results Mice receiving paclitaxel showed impaired short-term spatial memory acquisition both acutely 5 days post injection and chronically 23 days post injection. Dendritic length and complexity were reduced in the hippocampus and the prefrontal cortex after paclitaxel injection. Concurrently, the expression of protein kinase C α (PKCα), an effector in the InsP3R pathway, was increased. Treatment with lithium before or shortly after paclitaxel injection rescued the behavioral, cellular, and molecular deficits observed. Similarly, memory and morphological deficits could be rescued by pretreatment with chelerythrine, a PKC inhibitor. Conclusion We establish the InsP3R calcium pathway and impaired neuronal morphology as mechanisms for paclitaxel-induced cognitive impairment. Our findings suggest lithium and PKC inhibitors as candidate agents for preventing chemotherapy-induced cognitive impairment.

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