scholarly journals Impact of Gut Microbiome Lactobacillus spp. in Brain Function and its Medicament towards Alzheimer’s Disease Pathogenesis

2021 ◽  
Author(s):  
Shani Kunjamma John ◽  
Vani Chandrapragasam ◽  
Pinaki Dey
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Gut Microbiota ◽  
Brain Function ◽  
Neurodegenerative Dementia ◽  
Type Ii Diabetics ◽  
Health Complications ◽  
Effects Of Aging ◽  
The Brain ◽  
Significant Health

Alzheimer’s disease is neurodegenerative dementia which has significant health complications in the old age group. An imbalance in gut microbiota can influence to cause several diseases like chronic disorders, depression, type II diabetics, and neurological disorders like AD. Aging is one of the major causes of the development of neurodegenerative disease due to the decreasing levels of neurotransmitters, oxidative stress, chronic inflammation, and apoptosis. These harmful effects of aging can be prevented by probiotics usage. The gut-microbiota is capable to control the brain function through the gut-brain axis. Lactobacillus strains are considered as beneficial microorganism because of its importance of the maintenance in healthy intestinal microflora, immunomodulation, and intestinal pathogenic intervention. They have diverse applications in the medical field with properties like antioxidant, anticancer, anti-inflammatory, anti-proliferative, anti-obesity, and anti-diabetic activities. Probiotic supplementation with Lactobacillus strains shows an optimistic trend to use it as a significant therapy for cognitive symptoms. This review article put forwards the significance of the gut-brain axis and the contribution of Lactobacillus strains as a probiotic supplement and its therapeutic innovations for future aspects and the limitation to treat AD-related pathogenesis are briefly elucidated.

scholarly journals Gut Microbiota and Dysbiosis in Alzheimer’s Disease: Implications for Pathogenesis and Treatment

2020 ◽  
Vol 57 (12) ◽  
pp. 5026-5043 ◽  
Author(s):  
Shan Liu ◽  
Jiguo Gao ◽  
Mingqin Zhu ◽  
Kangding Liu ◽  
Hong-Liang Zhang
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Gut Microbiota ◽  
Gut Dysbiosis ◽  
Bidirectional Communication ◽  
Significant Research ◽  
Novel Therapeutic Strategies ◽  
The Brain ◽  
Brain Homeostasis ◽  
Gut Microbiota Composition

Abstract Understanding how gut flora influences gut-brain communications has been the subject of significant research over the past decade. The broadening of the term “microbiota-gut-brain axis” from “gut-brain axis” underscores a bidirectional communication system between the gut and the brain. The microbiota-gut-brain axis involves metabolic, endocrine, neural, and immune pathways which are crucial for the maintenance of brain homeostasis. Alterations in the composition of gut microbiota are associated with multiple neuropsychiatric disorders. Although a causal relationship between gut dysbiosis and neural dysfunction remains elusive, emerging evidence indicates that gut dysbiosis may promote amyloid-beta aggregation, neuroinflammation, oxidative stress, and insulin resistance in the pathogenesis of Alzheimer’s disease (AD). Illustration of the mechanisms underlying the regulation by gut microbiota may pave the way for developing novel therapeutic strategies for AD. In this narrative review, we provide an overview of gut microbiota and their dysregulation in the pathogenesis of AD. Novel insights into the modification of gut microbiota composition as a preventive or therapeutic approach for AD are highlighted.

Delirium, dementia, and other cognitive disorders

Psychiatry ◽  
2019 ◽  
Author(s):  
Rebecca McKnight ◽  
Jonathan Price ◽  
John Geddes
Keyword(s):  
Alzheimer’S Disease ◽  
Older Adults ◽  
Alzheimer's Disease ◽  
Cognitive Impairment ◽  
Psychiatric Disorders ◽  
Brain Function ◽  
Healthcare Services ◽  
Common Condition ◽  
Organic Brain Disease ◽  
The Brain

Organic psychiatric disorders result from brain dys­function caused by organic pathology inside or outside the brain. Dementia is the most common condition, with Alzheimer’s disease alone affecting 1 per cent of the population at 60 years, rising to 40 per cent over 80 years. Many of the rarer organic psychiatric dis­orders tend to affect a wider age range, but present in similar ways. Given the changing demographics of most developed countries, disorders producing cognitive im­pairment in older adults are becoming increasingly important for provision of healthcare services and in daily clinical practice. This chapter will cover the more common causes of cognitive impairment, and there is additional information in Chapters 18 and 20 on psych­iatry of older adults in psychiatry and medicine. There are three common clinical presentations of or­ganic psychiatric disorders: … 1 Delirium— an acute generalized impairment of brain function, in which the most important feature is impairment of consciousness. The disturbance of brain function is generalized, and the primary cause is often outside the brain; for example, sepsis due to a urinary tract infection. 2 Dementia— chronic generalized impairment, in which the main clinical feature is global intellectual impairment. There are also changes in mood and behaviour. The brain dysfunction is generalized, and the primary cause is within the brain; for example, a degenerative condition such as Alzheimer’s disease. 3 Specific syndromes— which include disorders with a predominant impairment of isolated areas; for example, memory (amnesic syndrome), thought, mood, or personality change. These include neurological disorders that frequently result in organic psychological complications; for example, epilepsy…. Table 26.1 lists the main categories of psychiatric disorder associated with organic brain disease. The following sections describe these syndromes and the psychiatric consequences of a number of neurological conditions. Organic causes of other core psychiatric conditions (e.g. anxiety and psychosis) are covered in the relevant specific chapters. Delirium is characterized by an acute impairment of consciousness producing a generalized cognitive impairment. The word delirium is derived from the Latin, ‘lira’, which means to wander from the furrow. Delirium is a common condition, affecting up to 30 per cent of patients in general medical or surgical wards, with the primary cause often being a sys­temic illness. The term ‘acute confusional state’ is a synonym for delirium.

Retinoic Acid and the Gut Microbiota in Alzheimer’s Disease: Fighting Back-to-Back?

2019 ◽  
Vol 16 (5) ◽  
pp. 405-417 ◽  
Author(s):  
Kristina Endres
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Retinoic Acid ◽  
Gut Microbiota ◽  
Disease Risk ◽  
Current Knowledge ◽  
Retinoid Signaling ◽  
Retinoid Metabolism ◽  
Organ Systems ◽  
The Brain

Background: There is growing evidence that the gut microbiota may play an important role in neurodegenerative diseases such as Alzheimer’s disease. However, how these commensals influence disease risk and progression still has to be deciphered. Objective: The objective of this review was to summarize current knowledge on the interplay between gut microbiota and retinoic acid. The latter one represents one of the important micronutrients, which have been correlated to Alzheimer’s disease and are used in initial therapeutic intervention studies. Methods: A selective overview of the literature is given with the focus on the function of retinoic acid in the healthy and diseased brain, its metabolism in the gut, and the potential influence that the bioactive ligand may have on microbiota, gut physiology and, Alzheimer’s disease. Results: Retinoic acid can influence neuronal functionality by means of plasticity but also by neurogenesis and modulating proteostasis. Impaired retinoid-signaling, therefore, might contribute to the development of diseases in the brain. Despite its rather direct impact, retinoic acid also influences other organ systems such as gut by regulating the residing immune cells but also factors such as permeability or commensal microbiota. These in turn can also interfere with retinoid-metabolism and via the gutbrain- axis furthermore with Alzheimer’s disease pathology within the brain. Conclusion: Potentially, it is yet too early to conclude from the few reports on changed microbiota in Alzheimer’s disease to a dysfunctional role in retinoid-signaling. However, there are several routes how microbial commensals might affect and might be affected by vitamin A and its derivatives.

Gut Microbiota and Alzheimer’s Disease: Pathophysiology and Therapeutic Perspectives

2021 ◽  
pp. 1-14
Author(s):  
Yanli Li ◽  
Rui Wang ◽  
Qian Li ◽  
Yan-Jiang Wang ◽  
Junhong Guo
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Gut Microbiota ◽  
Brain Function ◽  
Treatment Options ◽  
Amyloid Β ◽  
The Elderly ◽  
Protein Accumulation ◽  
Amyloid Β Protein ◽  
Dominant Bacteria

Alzheimer’s disease (AD) is the most common cause of dementia in the elderly and is characterized by a progressive decline in cognitive function. Amyloid-β protein accumulation is believed to be the key pathological hallmark of AD. Increasing evidence has shown that the gut microbiota has a role in brain function and host behaviors. The gut microbiota regulates the bidirectional interactions between the gut and brain through neural, endocrine, and immune pathways. With increasing age, the gut microbiota diversity decreases, and the dominant bacteria change, which is closely related to systemic inflammation and health status. Dysbiosis of the gut microbiota is related to cognitive impairment and neurodegenerative diseases. The purpose of this review is to discuss the impacts of the gut microbiota on brain function and the development of AD. It is a feasible target for therapeutic invention. Modulating the composition of the gut microbiota through diet, physical activity or probiotic/prebiotic supplements can provide new prevention and treatment options for AD.

Gut Microbiota and Alzheimer’s Disease: Experimental Evidence and Clinical Reality

2021 ◽  
Vol 18 ◽  
Author(s):  
Sarama Saha ◽  
Sukhpal Singh ◽  
Suvarna Prasad ◽  
Amit Mittal ◽  
Anil Kumar Sharma ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Gut Microbiota ◽  
Experimental Evidence ◽  
Molecular Mechanisms ◽  
Bacterial Flora ◽  
Experimental Studies ◽  
The Elderly ◽  
The Impact ◽  
The Brain

: Alzheimer’s disease (AD) is characterized by progressive death of neuronal cells in the regions of the brain concerned with memory and cognition, and is the major cause of dementia in the elderly population. Various molecular mechanisms, metabolic risk factors and environmental triggers contributing to the genesis and progression of AD are under intense investigations. The present review has dealt with the impact of a highly discussed topic of gut microbiota affecting the neurodegeneration in the AD brain. A detailed description of the composition of gut bacterial flora and its interaction with the host has been presented, followed by an analysis of key concepts of bi- directional communication between gut microbiota and the brain. The substantial experimental evidence of gut microbiota affecting the neurodegenerative process in experimental AD models has been described next in this review, and finally, the limitations of such experimental studies vis-a- vis the actual disease and the paucity of clinical data on this topic have also been mentioned.

scholarly journals The Oral-Gut-Brain AXIS: The Influence of Microbes in Alzheimer’s Disease

2021 ◽  
Vol 15 ◽  
Author(s):  
Narengaowa ◽  
Wei Kong ◽  
Fei Lan ◽  
Umer Farooq Awan ◽  
Hong Qing ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Gut Microbiota ◽  
Neurofibrillary Tangles ◽  
Neurodegenerative Disorders ◽  
Cranial Nerves ◽  
Neuronal Necrosis ◽  
Fundamental Causes ◽  
Oral Microbes ◽  
The Brain

Alzheimer’s disease (AD) is one of the most frequently diagnosed neurodegenerative disorders worldwide and poses a major challenge for both affected individuals and their caregivers. AD is a progressive neurological disorder associated with high rates of brain atrophy. Despite its durable influence on human health, understanding AD has been complicated by its enigmatic and multifactorial nature. Neurofibrillary tangles and the deposition of amyloid-beta (Aβ) protein are typical pathological features and fundamental causes of cognitive impairment in AD patients. Dysbiosis of oral and gut microbiota has been reported to induce and accelerate the formation of Aβ plaques and neurofibrillary tangles. For instance, some oral microbes can spread to the brain through cranial nerves or cellular infections, which has been suggested to increase the risk of developing AD. Importantly, the interaction between intestinal microbiota and brain cells has been recognized as influencing the development of AD as well as other neurodegenerative diseases. In particular, the metabolites produced by certain intestinal microorganisms can affect the activity of microglia and further mediate neuroinflammation, which is a leading cause of neuronal necrosis and AD pathogenesis. Which pathogens and associated pathways are involved in the development and progression of AD remains to be elucidated; however, it is well-known that gut microbiota and their metabolites can affect the brain by both direct and indirect means. Understanding the specific mechanisms involved in the interaction between these pathogens and the nervous system is vital for the early intervention in AD. In this review, we aim to comprehensively discuss the possible mechanistic pathways underlying the oral-brain, the gut-brain and the oral-gut-brain associations.

Pharmacological Strategies to Improve Dendritic Spines in Alzheimer’s Disease

2020 ◽  
pp. 1-17
Author(s):  
Miren Ettcheto ◽  
Oriol Busquets ◽  
Amanda Cano ◽  
Elena Sánchez-Lopez ◽  
Patricia R. Manzine ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Gut Microbiota ◽  
Dendritic Spines ◽  
Late Onset ◽  
Metabolic Stress ◽  
Environmental Stressors ◽  
Impact Pathways ◽  
Neurotrophic Factor Signaling ◽  
The Brain

To deeply understand late onset Alzheimer’s disease (LOAD), it may be necessary to change the concept that it is a disease exclusively driven by aging processes. The onset of LOAD could be associated with a previous peripheral stress at the level of the gut (changes in the gut microbiota), obesity (metabolic stress), and infections, among other systemic/environmental stressors. The onset of LOAD, then, may result from the generation of mild peripheral inflammatory processes involving cytokine production associated with peripheral stressors that in a second step enter the brain and spread out the process causing a neuroinflammatory brain disease. This hypothesis could explain the potential efficacy of Sodium Oligomannate (GV–971), a mixture of acidic linear oligosaccharides that have shown to remodel gut microbiota and slowdown LOAD. However, regardless of the origin of the disease, the end goal of LOAD–related preventative or disease modifying therapies is to preserve dendritic spines and synaptic plasticity that underlay and support healthy cognition. Here we discuss how systemic/environmental stressors impact pathways associated with the regulation of spine morphogenesis and synaptic maintenance, including insulin receptor and the brain derived neurotrophic factor signaling. Spine structure remodeling is a plausible mechanism to maintain synapses and provide cognitive resilience in LOAD patients. Importantly, we also propose a combination of drugs targeting such stressors that may be able to modify the course of LOAD by acting on preventing dendritic spines and synapsis loss.

scholarly journals Time to test antibacterial therapy in Alzheimer’s disease

Brain ◽  
2019 ◽  
Author(s):  
Francesco Panza ◽  
Madia Lozupone ◽  
Vincenzo Solfrizzi ◽  
Mark Watling ◽  
Bruno P Imbimbo
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Gut Microbiota ◽  
Blood Brain Barrier ◽  
Amyloid Β ◽  
The Other ◽  
Brain Barrier ◽  
The Past ◽  
Blood Brain ◽  
The Brain

Abstract Alzheimer’s disease is associated with cerebral accumulation of amyloid-β peptide and hyperphosphorylated tau. In the past 28 years, huge efforts have been made in attempting to treat the disease by reducing brain accumulation of amyloid-β in patients with Alzheimer’s disease, with no success. While anti-amyloid-β therapies continue to be tested in prodromal patients with Alzheimer’s disease and in subjects at risk of developing Alzheimer’s disease, there is an urgent need to provide therapeutic support to patients with established Alzheimer’s disease for whom current symptomatic treatment (acetylcholinesterase inhibitors and N-methyl d-aspartate antagonist) provide limited help. The possibility of an infectious aetiology for Alzheimer’s disease has been repeatedly postulated over the past three decades. Infiltration of the brain by pathogens may act as a trigger or co-factor for Alzheimer’s disease, with Herpes simplex virus type 1, Chlamydia pneumoniae, and Porphyromonas gingivalis being most frequently implicated. These pathogens may directly cross a weakened blood–brain barrier, reach the CNS and cause neurological damage by eliciting neuroinflammation. Alternatively, pathogens may cross a weakened intestinal barrier, reach vascular circulation and then cross blood–brain barrier or cause low grade chronic inflammation and subsequent neuroinflammation from the periphery. The gut microbiota comprises a complex community of microorganisms. Increased permeability of the gut and blood–brain barrier induced by microbiota dysbiosis may impact Alzheimer’s disease pathogenesis. Inflammatory microorganisms in gut microbiota are associated with peripheral inflammation and brain amyloid-β deposition in subjects with cognitive impairment. Oral microbiota may also influence Alzheimer’s disease risk through circulatory or neural access to the brain. At least two possibilities can be envisaged to explain the association of suspected pathogens and Alzheimer’s disease. One is that patients with Alzheimer’s disease are particularly prone to microbial infections. The other is that microbial infection is a contributing cause of Alzheimer’s disease. Therapeutic trials with antivirals and/or antibacterials could resolve this dilemma. Indeed, antiviral agents are being tested in patients with Alzheimer’s disease in double-blind placebo-controlled studies. Although combined antibiotic therapy was found to be effective in animal models of Alzheimer’s disease, antibacterial drugs are not being widely investigated in patients with Alzheimer’s disease. This is because it is not clear which bacterial populations in the gut of patients with Alzheimer’s disease are overexpressed and if safe, selective antibacterials are available for them. On the other hand, a bacterial protease inhibitor targeting P. gingivalis toxins is now being tested in patients with Alzheimer’s disease. Clinical studies are needed to test if countering bacterial infection may be beneficial in patients with established Alzheimer’s disease.

scholarly journals Gut Microbiota and Their Neuroinflammatory Implications in Alzheimer’s Disease

Nutrients ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1765 ◽  
Author(s):  
Vo Giau ◽  
Si Wu ◽  
Angelo Jamerlan ◽  
Seong An ◽  
SangYun Kim ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Gut Microbiota ◽  
Bidirectional Communication ◽  
The Central Nervous System ◽  
Brain And Behavior ◽  
Underlying Mechanisms ◽  
And Behavior ◽  
The Impact ◽  
The Brain

The bidirectional communication between the central nervous system (CNS) and the gut microbiota plays a pivotal role in human health. Increasing numbers of studies suggest that the gut microbiota can influence the brain and behavior of patients. Various metabolites secreted by the gut microbiota can affect the cognitive ability of patients diagnosed with neurodegenerative diseases. Nearly one in every ten Korean senior citizens suffers from Alzheimer’s disease (AD), the most common form of dementia. This review highlights the impact of metabolites from the gut microbiota on communication pathways between the brain and gut, as well as the neuroinflammatory roles they may have in AD patients. The objectives of this review are as follows: (1) to examine the role of the intestinal microbiota in homeostatic communication between the gut microbiota and the brain, termed the microbiota–gut–brain (MGB) axis; (2) to determine the underlying mechanisms of signal dysfunction; and (3) to assess the impact of signal dysfunction induced by the microbiota on AD. This review will aid in understanding the microbiota of elderly people and the neuroinflammatory roles they may have in AD.

Crosstalk between Gut Microbiota and Central Nervous System: A Focus on Alzheimer's Disease

2018 ◽  
Vol 15 (13) ◽  
pp. 1179-1190 ◽  
Author(s):  
Vilma M. Junges ◽  
Vera E. Closs ◽  
Guilherme M. Nogueira ◽  
Maria G.V. Gottlieb
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Central Nervous System ◽  
Nervous System ◽  
Gut Microbiota ◽  
System A ◽  
Bidirectional Communication ◽  
The Central Nervous System ◽  
The Brain

The role of diet and gut microbiota in the pathophysiology of neurodegenerative diseases, such as Alzheimer's, has recently come under intense investigation. Studies suggest that human gut microbiota may contribute to the modulation of several neurochemical and neurometabolic pathways, through complex systems that interact and interconnect with the central nervous system. The brain and intestine form a bidirectional communication axis, or vice versa, they form an axis through bi-directional communication between endocrine and complex immune systems, involving neurotransmitters and hormones. Above all, studies suggest that dysbiotic and poorly diversified microbiota may interfere with the synthesis and secretion of neurotrophic factors, such as brain-derived neurotrophic factor, gammaaminobutyric acid and N-methyl D-Aspartate receptors, widely associated with cognitive decline and dementia. In this context, the present article provides a review of the literature on the role of the gutbrain axis in Alzheimer's disease.

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