scholarly journals Age-associated gut microbiota impairs hippocampus-dependent memory in a vagus-dependent manner

2021 ◽  
Author(s):  
Damien Rei ◽  
Soham Saha ◽  
Marianne Haddad ◽  
Anna Haider Rubio ◽  
Marie-Noelle Ungeheuer ◽  
...  

AbstractAging is known to be associated with hippocampus-dependent memory decline, but the underlying causes of this age-related memory impairment are not yet elucidated. Here we show that the colonization of mice with the gut microbiota from aged, but not young animals is sufficient to trigger profound hippocampal alterations including astrogliosis, decreased adult neurogenesis, decreased novelty-induced neuronal activation and impairment in hippocampal-dependent memory. Similar alterations were reported in mice following the transfer of microbiota from aged human healthy donors. To decipher the mechanisms involved in mediating these microbiota-induced effects on brain functioning, we mapped the neuronal activity patterns and report that aged-microbiota transplantation reduced neuronal activity upstream to the vagus nerve. Targeted pharmacogenetic manipulation of the ascending branch of the vagus nerve demonstrated that the mere decrease in vagal activity was also detrimental to hippocampal functions. In contrast, increasing vagal activity alleviated the adverse effects of age-associated microbiota transfer on hippocampal functions and reinstated normal hippocampal memory in aged mice. We conclude that vagus nerve stimulation is a potential therapeutic strategy to lessen microbiota-dependent age-associated impairments in hippocampal functions.Graphical abstract

Gut ◽  
2022 ◽  
pp. gutjnl-2021-326269
Author(s):  
Chun Chen ◽  
Jianming Liao ◽  
Yiyuan Xia ◽  
Xia Liu ◽  
Rheinallt Jones ◽  
...  

ObjectiveThis study is to investigate the role of gut dysbiosis in triggering inflammation in the brain and its contribution to Alzheimer’s disease (AD) pathogenesis.DesignWe analysed the gut microbiota composition of 3×Tg mice in an age-dependent manner. We generated germ-free 3×Tg mice and recolonisation of germ-free 3×Tg mice with fecal samples from both patients with AD and age-matched healthy donors.ResultsMicrobial 16S rRNA sequencing revealed Bacteroides enrichment. We found a prominent reduction of cerebral amyloid-β plaques and neurofibrillary tangles pathology in germ-free 3×Tg mice as compared with specific-pathogen-free mice. And hippocampal RNAseq showed that inflammatory pathway and insulin/IGF-1 signalling in 3×Tg mice brain are aberrantly altered in the absence of gut microbiota. Poly-unsaturated fatty acid metabolites identified by metabolomic analysis, and their oxidative enzymes were selectively elevated, corresponding with microglia activation and inflammation. AD patients’ gut microbiome exacerbated AD pathologies in 3×Tg mice, associated with C/EBPβ/asparagine endopeptidase pathway activation and cognitive dysfunctions compared with healthy donors’ microbiota transplants.ConclusionsThese findings support that a complex gut microbiome is required for behavioural defects, microglia activation and AD pathologies, the gut microbiome contributes to pathologies in an AD mouse model and that dysbiosis of the human microbiome might be a risk factor for AD.


2003 ◽  
Vol 82 (8) ◽  
pp. 657-660 ◽  
Author(s):  
M. Onozuka ◽  
M. Fujita ◽  
K. Watanabe ◽  
Y. Hirano ◽  
M. Niwa ◽  
...  

Age-related changes in mastication-induced brain neuronal activity have been suggested. However, in humans, little is known about the anatomical regions involved. Using fMRI during cycles of rhythmic gum-chewing and no chewing, we have examined the effect of aging on brain regional activity during chewing in young adult (19–26 yrs), middle-aged (42–55 yrs), and aged (65–73 yrs) healthy humans. In all subjects, chewing resulted in a bilateral increase in the BOLD signals in the sensorimotor cortex, cerebellum, thalamus, supplementary motor area, and insula, and a unilateral increase in the right prefrontal area. In the first three regions, the signal increases were attenuated in an age-dependent manner, whereas, in the right prefrontal area, the converse was seen. The remaining two regions showed no significant differences with ages. These results indicate that chewing causes regional increases in neuronal activity in the brain, some of which are age-dependent.


2020 ◽  
Author(s):  
Jude M. Phillip ◽  
Nahuel Zamponi ◽  
Madonna P. Phillip ◽  
Jena Daya ◽  
Shaun McGovern ◽  
...  

ABSTRACTAgeing in humans is associated with a decreased capacity to regulate cell physiology. Cellular properties, such as cell morphology and cell mechanics, encode ageing information and as a result can be used as robust ageing biomarkers. Using a panel of dermal fibroblasts derived from healthy donors spanning a wide age range, we observe an age-related reduction in average cell motility, which we show is not due to the decreased motility of all cells, but results from fractional re-distribution among motility states. By taking advantage of the single-cell nature of our motility data, we show that cells can be classified based on spatial and activity patterns that define age-dependent motility states. These findings highlight an important feature of ageing cells shown by the decrease in the heterogeneity of cell movement in older adults, that potentially offer new mechanistic insights into the ageing process and avenues for novel biomarker development.


Author(s):  
Mehdi Talebi ◽  
Mousa Vatanmakanian ◽  
Ali Mirzaei ◽  
Yaghoub Barfar ◽  
Maryam Hemmatzadeh ◽  
...  

Background: Platelet-rich (PRP) and Platelet-poor plasma (PPP) are widely used in research and clinical platforms mainly due to their capacities to enhance cell growth. Although short half-life (5 days) and the high price of platelet products pose challenges regarding their usage, they maintain the growth regulatory functions for weeks. Thus, we aimed to assess the supplementary values of these products in human CCRF-CEM cancer cells. Mechanistically, we also checked if the PRP/PPP treatment enhances YKL-40 expression as a known protein regulating cell growth. Methods: The PRP/PPP was prepared from healthy donors using manual stepwise centrifugation and phase separation. The viability of the cells treated with gradient PRP/PPP concentrations (2, 5, 10, and 15%) was measured by the MTT assay. The YKL-40 mRNA and protein levels were assessed using qRT-PCR and western blotting. The data were compared to FBS-treated cells. Result: Our findings revealed that the cells treated by PRP/PPP not only were morphologically comparable to those treated by FBS but also, they showed greater viability at the concentrations of 10 and 15%. Moreover, it was shown that PRP/PPP induce cell culture support, at least in part, via inducing YKL-40 expression at both mRNA and protein levels in a time- and dose-dependent manner. Conclusion: Collectively, by showing cell culture support comparable to FBS, the PRP/PPP might be used as good candidates to supplement the cancer cell culture and overcome concerns regarding the use of FBS as a non-human source in human cancer research.


Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 801
Author(s):  
Jehun Choi ◽  
Gwi-Yeong Jang ◽  
Jeonghoon Lee ◽  
Hae-Young Chung ◽  
Hyung-Jun Noh ◽  
...  

Senescence is the phenomenon by which physiological functions of organisms degenerate with time. Cellular senescence is marked by an inhibition of cell cycle progression. Beta-galactosidase accumulates in the lysosomes of aged cells. In this study, human dermal fibroblast cells (HDFs) were treated with 0.5 μM doxorubicin for 4 h to induce cellular senescence. Senescence-associated beta-galactosidase (SA-β-gal) activity was then measured 72 h after treatment with aerial parts of Dendranthema zawadskii var. lucidum (Nakai) J.H. Park (DZ) extract. Treatment with DZ extract significantly decreased SA-β-gal activity in a dose-dependent manner in HDFs. Additionally, DZ extract treatment reduced age-related oxidative stress and inflammation in the aortas of aged rats. The reactive oxygen species (ROS) levels in aortas of aged control rats were higher than those in young rats. However, DZ extract-fed aged rats showed significantly lower ROS levels than the aged control rats. When the aged rats were treated with DZ extract at either 0.2 or 1.0 mg∙kg−1∙day−1, NF-κB levels in aorta tissue decreased significantly compared to those in aorta tissue of the aged control rats without DZ treatment. In addition, DZ extract-fed aged rat aortas showed significant reductions in expression of iNOS and COX-2 induced by NF-κB translocation. Therefore, these results suggest that DZ effectively inhibited senescence-related NF-κB activation and inflammation. DZ extract may have a role in the prevention of the vascular inflammatory responses that occur during vascular aging.


Author(s):  
Morten Orebo Holmström ◽  
Rasmus Erik Johansson Mortensen ◽  
Angelos Michail Pavlidis ◽  
Evelina Martinenaite ◽  
Stine Emilie Weis-Banke ◽  
...  

2021 ◽  
Vol 16 ◽  
pp. 263310552110184
Author(s):  
Lavanya Venkatasamy ◽  
Damir Nizamutdinov ◽  
Jaclyn Jenkins ◽  
Lee A Shapiro

Gulf war illness (GWI), is a chronic multi-symptom illness that has impacted approximately one-third of the veterans who served in the 1990 to 1991 Gulf War. GWI symptoms include cognitive impairments (eg, memory and concentration problems), headaches, migraines, fatigue, gastrointestinal and respiratory issues, as well as emotional deficits. The exposure to neurological chemicals such as the anti-nerve gas drug, pyridostigmine bromide (PB), and the insecticide permethrin (PER), may contribute to the etiologically related factors of GWI. Various studies utilizing mouse models of GWI have reported the interplay of these chemical agents in increasing neuroinflammation and cognitive dysfunction. Astrocytes are involved in the secretion of neuroinflammatory cytokines and chemokines in pathological conditions and have been implicated in GWI symptomology. We hypothesized that exposure to PB and PER causes lasting changes to hippocampal astrocytes, concurrent with chronic cognitive deficits that can be reversed by cervical vagus nerve stimulation (VNS). GWI was induced in CD1 mice by injecting the mixture of PER (200 mg/kg) and PB (2 mg/kg), i.p. for 10 consecutive days. VNS stimulators were implanted at 33 weeks after GWI induction. The results show age-related cognitive alterations at approximately 9 months after exposure to PB and PER. The results also showed an increased number of GFAP-labeled astrocytes in the hippocampus and dentate gyrus that was ameliorated by VNS.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Velma T. E. Aho ◽  
Madelyn C. Houser ◽  
Pedro A. B. Pereira ◽  
Jianjun Chang ◽  
Knut Rudi ◽  
...  

Abstract Background Previous studies have reported that gut microbiota, permeability, short-chain fatty acids (SCFAs), and inflammation are altered in Parkinson’s disease (PD), but how these factors are linked and how they contribute to disease processes and symptoms remains uncertain. This study sought to compare and identify associations among these factors in PD patients and controls to elucidate their interrelations and links to clinical manifestations of PD. Methods Stool and plasma samples and clinical data were collected from 55 PD patients and 56 controls. Levels of stool SCFAs and stool and plasma inflammatory and permeability markers were compared between patients and controls and related to one another and to the gut microbiota. Results Calprotectin was increased and SCFAs decreased in stool in PD in a sex-dependent manner. Inflammatory markers in plasma and stool were neither intercorrelated nor strongly associated with SCFA levels. Age at PD onset was positively correlated with SCFAs and negatively correlated with CXCL8 and IL-1β in stool. Fecal zonulin correlated positively with fecal NGAL and negatively with PD motor and non-motor symptoms. Microbiota diversity and composition were linked to levels of SCFAs, inflammatory factors, and zonulin in stool. Certain relationships differed between patients and controls and by sex. Conclusions Intestinal inflammatory responses and reductions in fecal SCFAs occur in PD, are related to the microbiota and to disease onset, and are not reflected in plasma inflammatory profiles. Some of these relationships are distinct in PD and are sex-dependent. This study revealed potential alterations in microbiota-host interactions and links between earlier PD onset and intestinal inflammatory responses and reduced SCFA levels, highlighting candidate molecules and pathways which may contribute to PD pathogenesis and clinical presentation and which warrant further investigation.


2021 ◽  
Vol 9 (5) ◽  
pp. 1037
Author(s):  
Craig Resch ◽  
Mihir Parikh ◽  
J. Alejandro Austria ◽  
Spencer D. Proctor ◽  
Thomas Netticadan ◽  
...  

There is an increased interest in the gut microbiota as it relates to health and obesity. The impact of diet and sex on the gut microbiota in conjunction with obesity also demands extensive systemic investigation. Thus, the influence of sex, diet, and flaxseed supplementation on the gut microbiota was examined in the JCR:LA-cp rat model of genetic obesity. Male and female obese rats were randomized into four groups (n = 8) to receive, for 12 weeks, either (a) control diet (Con), (b) control diet supplemented with 10% ground flaxseed (CFlax), (c) a high-fat, high sucrose (HFHS) diet, or (d) HFHS supplemented with 10% ground flaxseed (HFlax). Male and female JCR:LA-cp lean rats served as genetic controls and received similar dietary interventions. Illumine MiSeq sequencing revealed a richer microbiota in rats fed control diets rather than HFHS diets. Obese female rats had lower alpha-diversity than lean female; however, both sexes of obese and lean JCR rats differed significantly in β-diversity, as their gut microbiota was composed of different abundances of bacterial types. The feeding of an HFHS diet affected the diversity by increasing the phylum Bacteroidetes and reducing bacterial species from phylum Firmicutes. Fecal short-chain fatty acids such as acetate, propionate, and butyrate-producing bacterial species were correspondingly impacted by the HFHS diet. Flax supplementation improved the gut microbiota by decreasing the abundance of Blautia and Eubacterium dolichum. Collectively, our data show that an HFHS diet results in gut microbiota dysbiosis in a sex-dependent manner. Flaxseed supplementation to the diet had a significant impact on gut microbiota diversity under both flax control and HFHS dietary conditions.


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