scholarly journals A fiber-deprived diet causes cognitive impairment and hippocampal microglia-mediated synaptic loss through the gut microbiota and metabolites

Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Hongli Shi ◽  
Xing Ge ◽  
Xi Ma ◽  
Mingxuan Zheng ◽  
Xiaoying Cui ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Gut Microbiota ◽  
Neurodegenerative Diseases ◽  
Dietary Fiber ◽  
Brain Aging ◽  
Synaptic Proteins ◽  
Aging Brain ◽  
Normal Brain ◽  
Fiber Intake ◽  
Synaptic Ultrastructure

Abstract Background Cognitive impairment, an increasing mental health issue, is a core feature of the aging brain and neurodegenerative diseases. Industrialized nations especially, have experienced a marked decrease in dietary fiber intake, but the potential mechanism linking low fiber intake and cognitive impairment is poorly understood. Emerging research reported that the diversity of gut microbiota in Western populations is significantly reduced. However, it is unknown whether a fiber-deficient diet (which alters gut microbiota) could impair cognition and brain functional elements through the gut-brain axis. Results In this study, a mouse model of long-term (15 weeks) dietary fiber deficiency (FD) was used to mimic a sustained low fiber intake in humans. We found that FD mice showed impaired cognition, including deficits in object location memory, temporal order memory, and the ability to perform daily living activities. The hippocampal synaptic ultrastructure was damaged in FD mice, characterized by widened synaptic clefts and thinned postsynaptic densities. A hippocampal proteomic analysis further identified a deficit of CaMKIId and its associated synaptic proteins (including GAP43 and SV2C) in the FD mice, along with neuroinflammation and microglial engulfment of synapses. The FD mice also exhibited gut microbiota dysbiosis (decreased Bacteroidetes and increased Proteobacteria), which was significantly associated with the cognitive deficits. Of note, a rapid differentiating microbiota change was observed in the mice with a short-term FD diet (7 days) before cognitive impairment, highlighting a possible causal impact of the gut microbiota profile on cognitive outcomes. Moreover, the FD diet compromised the intestinal barrier and reduced short-chain fatty acid (SCFA) production. We exploit these findings for SCFA receptor knockout mice and oral SCFA supplementation that verified SCFA playing a critical role linking the altered gut microbiota and cognitive impairment. Conclusions This study, for the first time, reports that a fiber-deprived diet leads to cognitive impairment through altering the gut microbiota-hippocampal axis, which is pathologically distinct from normal brain aging. These findings alert the adverse impact of dietary fiber deficiency on brain function, and highlight an increase in fiber intake as a nutritional strategy to reduce the risk of developing diet-associated cognitive decline and neurodegenerative diseases.

scholarly journals Low dietary fiber intake increases Collinsella abundance in the gut microbiota of overweight and obese pregnant women

Gut Microbes ◽  
2018 ◽  
Vol 9 (3) ◽  
pp. 189-201 ◽  
Author(s):  
Luisa F. Gomez-Arango ◽  
Helen L. Barrett ◽  
Shelley A. Wilkinson ◽  
Leonie K. Callaway ◽  
H. David McIntyre ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Pregnant Women ◽  
Dietary Fiber ◽  
Fiber Intake ◽  
Dietary Fiber Intake

1H-MR spectroscopy differentiates mild cognitive impairment from normal brain aging

Neuroreport ◽  
2001 ◽  
Vol 12 (11) ◽  
pp. 2315-2317 ◽  
Author(s):  
Marco Catani ◽  
Antonio Cherubini ◽  
Robert Howard ◽  
Roberto Tarducci ◽  
GianPiero Pelliccioli ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Mr Spectroscopy ◽  
Brain Aging ◽  
Normal Brain ◽  
1H Mr Spectroscopy

scholarly journals Transcriptomic Changes Highly Similar to Alzheimer’s Disease Are Observed in a Subpopulation of Individuals During Normal Brain Aging

2021 ◽  
Vol 13 ◽  
Author(s):  
Shouneng Peng ◽  
Lu Zeng ◽  
Jean-Vianney Haure-Mirande ◽  
Minghui Wang ◽  
Derek M. Huffman ◽  
...  
Keyword(s):  
Gene Expression ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Healthy Aging ◽  
Brain Aging ◽  
Normal Aging ◽  
Aging Brain ◽  
Normal Brain ◽  
Older Individuals ◽  
Cognitively Normal

Aging is a major risk factor for late-onset Alzheimer’s disease (LOAD). How aging contributes to the development of LOAD remains elusive. In this study, we examined multiple large-scale transcriptomic datasets from both normal aging and LOAD brains to understand the molecular interconnection between aging and LOAD. We found that shared gene expression changes between aging and LOAD are mostly seen in the hippocampal and several cortical regions. In the hippocampus, the expression of phosphoprotein, alternative splicing and cytoskeleton genes are commonly changed in both aging and AD, while synapse, ion transport, and synaptic vesicle genes are commonly down-regulated. Aging-specific changes are associated with acetylation and methylation, while LOAD-specific changes are more related to glycoprotein (both up- and down-regulations), inflammatory response (up-regulation), myelin sheath and lipoprotein (down-regulation). We also found that normal aging brain transcriptomes from relatively young donors (45–70 years old) clustered into several subgroups and some subgroups showed gene expression changes highly similar to those seen in LOAD brains. Using brain transcriptomic datasets from another cohort of older individuals (>70 years), we found that samples from cognitively normal older individuals clustered with the “healthy aging” subgroup while AD samples mainly clustered with the “AD similar” subgroups. This may imply that individuals in the healthy aging subgroup will likely remain cognitively normal when they become older and vice versa. In summary, our results suggest that on the transcriptome level, aging and LOAD have strong interconnections in some brain regions in a subpopulation of cognitively normal aging individuals. This supports the theory that the initiation of LOAD occurs decades earlier than the manifestation of clinical phenotype and it may be essential to closely study the “normal brain aging” to identify the very early molecular events that may lead to LOAD development.

scholarly journals Dietary Fiber Intake Alters Gut Microbiota Composition but Does Not Improve Gut Wall Barrier Function in Women with Future Hypertensive Disorders of Pregnancy

Nutrients ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3862
Author(s):  
Kate I. Tomsett ◽  
Helen L. Barrett ◽  
Evelyn E. Dekker ◽  
Leonie K. Callaway ◽  
David H. McIntyre ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Dietary Fiber ◽  
Barrier Function ◽  
Microbiota Composition ◽  
Fiber Intake ◽  
Hypertensive Disorders Of Pregnancy ◽  
Dietary Fiber Intake ◽  
Hypertensive Disorders ◽  
Lower Abundance ◽  
Gut Microbiota Composition

Pregnancy alters the inflammatory state, metabolic hormones, and gut microbiota composition. It is unclear if the lower abundance of dietary fiber-fermenting, short-chain fatty acid-producing bacteria observed in hypertension also occurs in hypertensive disorders of pregnancy (HDP). This study investigated the relationship between dietary fiber intake and the gut microbiota profile at 28 weeks gestation in women who developed HDP in late pregnancy (n = 22) or remained normotensive (n = 152) from the Study of PRobiotics IN Gestational diabetes (SPRING). Dietary fiber intake was classified as above or below the median of 18.2 g/day. Gut microbiota composition was examined using 16S rRNA gene amplicon sequencing. The gut permeability marker zonulin was measured in a subset of 46 samples. In women with future HPD, higher dietary fiber intake was specifically associated with increased abundance of Veillonella, lower abundance of Adlercreutzia, Anaerotruncus and Uncl. Mogibacteriaceae and higher zonulin levels than normotensive women. Fiber intake and zonulin levels were negatively correlated in women with normotensive pregnancies but not in pregnancies with future HDP. In women with normotensive pregnancies, dietary fiber intake may improve gut barrier function. In contrast, in women who develop HDP, gut wall barrier function is impaired and not related to dietary fiber intake.

scholarly journals Neurophysiological Hallmarks of Neurodegenerative Cognitive Decline: The Study of Brain Connectivity as A Biomarker of Early Dementia

2020 ◽  
Vol 10 (2) ◽  
pp. 34 ◽  
Author(s):  
Paolo Maria Rossini ◽  
Francesca Miraglia ◽  
Francesca Alù ◽  
Maria Cotelli ◽  
Florinda Ferreri ◽  
...  
Keyword(s):  
Brain Aging ◽  
Brain Connectivity ◽  
Intermediate Stage ◽  
Synaptic Function ◽  
General Interest ◽  
Aging Brain ◽  
Healthy Population ◽  
Normal Brain ◽  
Non Invasive ◽  
Learning Machine

Neurodegenerative processes of various types of dementia start years before symptoms, but the presence of a “neural reserve”, which continuously feeds and supports neuroplastic mechanisms, helps the aging brain to preserve most of its functions within the “normality” frame. Mild cognitive impairment (MCI) is an intermediate stage between dementia and normal brain aging. About 50% of MCI subjects are already in a stage that is prodromal-to-dementia and during the following 3 to 5 years will develop clinically evident symptoms, while the other 50% remains at MCI or returns to normal. If the risk factors favoring degenerative mechanisms are modified during early stages (i.e., in the prodromal), the degenerative process and the loss of abilities in daily living activities will be delayed. It is therefore extremely important to have biomarkers able to identify—in association with neuropsychological tests—prodromal-to-dementia MCI subjects as early as possible. MCI is a large (i.e., several million in EU) and substantially healthy population; therefore, biomarkers should be financially affordable, largely available and non-invasive, but still accurate in their diagnostic prediction. Neurodegeneration initially affects synaptic transmission and brain connectivity; methods exploring them would represent a 1st line screening. Neurophysiological techniques able to evaluate mechanisms of synaptic function and brain connectivity are attracting general interest and are described here. Results are quite encouraging and suggest that by the application of artificial intelligence (i.e., learning-machine), neurophysiological techniques represent valid biomarkers for screening campaigns of the MCI population.

scholarly journals The Microbiota–Gut–Brain Axis–Heart Shunt Part II: Prosaic Foods and the Brain–Heart Connection in Alzheimer Disease

2020 ◽  
Vol 8 (4) ◽  
pp. 493 ◽  
Author(s):  
Mark Obrenovich ◽  
Shams Tabrez ◽  
Bushra Siddiqui ◽  
Benjamin McCloskey ◽  
George Perry
Keyword(s):  
Alzheimer Disease ◽  
Gut Microbiota ◽  
Neurodegenerative Diseases ◽  
Vascular Dementia ◽  
Brain Aging ◽  
Polyphenolic Compounds ◽  
Heart Health ◽  
Host Liver ◽  
The Brain ◽  
French Paradox

There is a strong cerebrovascular component to brain aging, Alzheimer disease, and vascular dementia. Foods, common drugs, and the polyphenolic compounds contained in wine modulate health both directly and through the gut microbiota. This observation and novel findings centered on nutrition, biochemistry, and metabolism, as well as the newer insights we gain into the microbiota-gut-brain axis, now lead us to propose a shunt to this classic triad, which involves the heart and cerebrovascular systems. The French paradox and prosaic foods, as they relate to the microbiota-gut-brain axis and neurodegenerative diseases, are discussed in this manuscript, which is the second part of a two-part series of concept papers addressing the notion that the microbiota and host liver metabolism all play roles in brain and heart health.

The effects of aging, injury and disease on microglial function: a case for cellular senescence

2007 ◽  
Vol 3 (3) ◽  
pp. 245-253 ◽  
Author(s):  
Kelly R. Miller ◽  
Wolfgang J. Streit
Keyword(s):  
Neurodegenerative Diseases ◽  
Cellular Senescence ◽  
Current Knowledge ◽  
Treatment Strategies ◽  
Aging Brain ◽  
Normal Brain ◽  
Age Related ◽  
Anti Inflammatory ◽  
Effects Of Aging ◽  
And Function

AbstractNeuroinflammation resulting from chronic reactive microgliosis is thought to contribute to age-related neurodegeneration, as well as age-related neurodegenerative diseases, specifically Alzheimer's disease (AD). Support of this theory comes from studies reporting a progressive, age-associated increase in microglia with an activated phenotype. Although the underlying cause(s) of this microglial reactivity is idiopathic, an accepted therapeutic strategy for the treatment of AD is inhibition of microglial activation using anti-inflammatory agents. Although the effectiveness of anti-inflammatory treatment for AD remains equivocal, microglial inhibition is being tested as a potential treatment for additional neurodegenerative disorders including amyotrophic lateral sclerosis and Parkinson's disease. Given the important and necessary functions of microglia in normal brain, careful evaluation of microglial function in the aged brain is a necessary first step in targeting more precise treatment strategies for aging-related neurodegenerative diseases. Studies from our laboratory have shown multiple age-related changes in microglial morphology and function that are suggestive of cellular senescence. In this manuscript, we review current knowledge of microglia in the aging brain and present new, unpublished work that further supports the theory that microglia experience an age-related decline in proliferative function as a result of cellular senescence.

scholarly journals Effects of dietary restriction on neuroinflammation in neurodegenerative diseases

2021 ◽  
Vol 218 (2) ◽  
Author(s):  
Luigi Fontana ◽  
Laura Ghezzi ◽  
Anne H. Cross ◽  
Laura Piccio
Keyword(s):  
Neurodegenerative Diseases ◽  
Gut Microbiome ◽  
Food Restriction ◽  
Brain Aging ◽  
Cellular Tissue ◽  
Calorie Intake ◽  
Normal Brain ◽  
Meal Frequency ◽  
Peripheral Metabolism ◽  
Lateral Sclerosis

Recent and accumulating work in experimental animal models and humans shows that diet has a much more pervasive and prominent role than previously thought in modulating neuroinflammatory and neurodegenerative mechanisms leading to some of the most common chronic central nervous system (CNS) diseases. Chronic or intermittent food restriction has profound effects in shaping brain and peripheral metabolism, immunity, and gut microbiome biology. Interactions among calorie intake, meal frequency, diet quality, and the gut microbiome modulate specific metabolic and molecular pathways that regulate cellular, tissue, and organ homeostasis as well as inflammation during normal brain aging and CNS neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, and multiple sclerosis, among others. This review discusses these findings and their potential application to the prevention and treatment of CNS neuroinflammatory diseases and the promotion of healthy brain aging.

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