scholarly journals The Microbiota–Gut–Brain Axis and Alzheimer’s Disease: Neuroinflammation Is to Blame?

Nutrients ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 37
Author(s):  
Ashwinipriyadarshini Megur ◽  
Daiva Baltriukienė ◽  
Virginija Bukelskienė ◽  
Aurelijus Burokas

For years, it has been reported that Alzheimer’s disease (AD) is the most common cause of dementia. Various external and internal factors may contribute to the early onset of AD. This review highlights a contribution of the disturbances in the microbiota–gut–brain (MGB) axis to the development of AD. Alteration in the gut microbiota composition is determined by increase in the permeability of the gut barrier and immune cell activation, leading to impairment in the blood–brain barrier function that promotes neuroinflammation, neuronal loss, neural injury, and ultimately AD. Numerous studies have shown that the gut microbiota plays a crucial role in brain function and changes in the behavior of individuals and the formation of bacterial amyloids. Lipopolysaccharides and bacterial amyloids synthesized by the gut microbiota can trigger the immune cells residing in the brain and can activate the immune response leading to neuroinflammation. Growing experimental and clinical data indicate the prominent role of gut dysbiosis and microbiota–host interactions in AD. Modulation of the gut microbiota with antibiotics or probiotic supplementation may create new preventive and therapeutic options in AD. Accumulating evidences affirm that research on MGB involvement in AD is necessary for new treatment targets and therapies for AD.

Gut ◽  
2019 ◽  
Vol 69 (2) ◽  
pp. 283-294 ◽  
Author(s):  
Min-Soo Kim ◽  
Yoonhee Kim ◽  
Hyunjung Choi ◽  
Woojin Kim ◽  
Sumyung Park ◽  
...  

ObjectiveCerebral amyloidosis and severe tauopathy in the brain are key pathological features of Alzheimer’s disease (AD). Despite a strong influence of the intestinal microbiota on AD, the causal relationship between the gut microbiota and AD pathophysiology is still elusive.DesignUsing a recently developed AD-like pathology with amyloid and neurofibrillary tangles (ADLPAPT) transgenic mouse model of AD, which shows amyloid plaques, neurofibrillary tangles and reactive gliosis in their brains along with memory deficits, we examined the impact of the gut microbiota on AD pathogenesis.ResultsComposition of the gut microbiota in ADLPAPT mice differed from that of healthy wild-type (WT) mice. Besides, ADLPAPT mice showed a loss of epithelial barrier integrity and chronic intestinal and systemic inflammation. Both frequent transfer and transplantation of the faecal microbiota from WT mice into ADLPAPT mice ameliorated the formation of amyloid β plaques and neurofibrillary tangles, glial reactivity and cognitive impairment. Additionally, the faecal microbiota transfer reversed abnormalities in the colonic expression of genes related to intestinal macrophage activity and the circulating blood inflammatory monocytes in the ADLPAPT recipient mice.ConclusionThese results indicate that microbiota-mediated intestinal and systemic immune aberrations contribute to the pathogenesis of AD in ADLPAPT mice, providing new insights into the relationship between the gut (colonic gene expression, gut permeability), blood (blood immune cell population) and brain (pathology) axis and AD (memory deficits). Thus, restoring gut microbial homeostasis may have beneficial effects on AD treatment.


2013 ◽  
Vol 20 (37) ◽  
pp. 4806-4814 ◽  
Author(s):  
Brigitta Buttari ◽  
Elisabetta Profumo ◽  
Rita Businaro ◽  
Luciano Saso ◽  
Raffaele Capoano ◽  
...  

2020 ◽  
Vol 57 (12) ◽  
pp. 5026-5043 ◽  
Author(s):  
Shan Liu ◽  
Jiguo Gao ◽  
Mingqin Zhu ◽  
Kangding Liu ◽  
Hong-Liang Zhang

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.


2021 ◽  
Vol 116 (1) ◽  
Author(s):  
Marius Keller ◽  
Valbona Mirakaj ◽  
Michael Koeppen ◽  
Peter Rosenberger

AbstractCardiovascular pathologies are often induced by inflammation. The associated changes in the inflammatory response influence vascular endothelial biology; they complicate the extent of ischaemia and reperfusion injury, direct the migration of immune competent cells and activate platelets. The initiation and progression of inflammation is regulated by the classical paradigm through the system of cytokines and chemokines. Therapeutic approaches have previously used this knowledge to control the extent of cardiovascular changes with varying degrees of success. Neuronal guidance proteins (NGPs) have emerged in recent years and have been shown to be significantly involved in the control of tissue inflammation and the mechanisms of immune cell activation. Therefore, proteins of this class might be used in the future as targets to control the extent of inflammation in the cardiovascular system. In this review, we describe the role of NGPs during cardiovascular inflammation and highlight potential therapeutic options that could be explored in the future.


Nutrients ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 690
Author(s):  
Umair Shabbir ◽  
Muhammad Sajid Arshad ◽  
Aysha Sameen ◽  
Deog-Hwan Oh

The gut microbiota (GM) represents a diverse and dynamic population of microorganisms and about 100 trillion symbiotic microbial cells that dwell in the gastrointestinal tract. Studies suggest that the GM can influence the health of the host, and several factors can modify the GM composition, such as diet, drug intake, lifestyle, and geographical locations. Gut dysbiosis can affect brain immune homeostasis through the microbiota–gut–brain axis and can play a key role in the pathogenesis of neurodegenerative diseases, including dementia and Alzheimer’s disease (AD). The relationship between gut dysbiosis and AD is still elusive, but emerging evidence suggests that it can enhance the secretion of lipopolysaccharides and amyloids that may disturb intestinal permeability and the blood–brain barrier. In addition, it can promote the hallmarks of AD, such as oxidative stress, neuroinflammation, amyloid-beta formation, insulin resistance, and ultimately the causation of neural death. Poor dietary habits and aging, along with inflammatory responses due to dysbiosis, may contribute to the pathogenesis of AD. Thus, GM modulation through diet, probiotics, or fecal microbiota transplantation could represent potential therapeutics in AD. In this review, we discuss the role of GM dysbiosis in AD and potential therapeutic strategies to modulate GM in AD.


Pteridines ◽  
2020 ◽  
Vol 31 (1) ◽  
pp. 68-82
Author(s):  
Gregory Baxter-Parker ◽  
Ravinder Reddy Gaddam ◽  
Elena Moltchanova ◽  
Anitra Carr ◽  
Geoff Shaw ◽  
...  

AbstractIntroduction: Neopterin and 7,8-dihydroneopterin are used as biomarkers of oxidative stress and inflammation, but the effect of kidney function on these measurements has not been extensively explored. We examine the levels of oxidative stress, inflammation and kidney function in intensive patients and compare them to equivalent patients without sepsis.Methods: 34 Intensive care patients were selected for the study, 14 without sepsis and 20 with. Both groups had equivalent levels of trauma, assessed by SAPS II, SOFA, and APACHE II and III scores. Plasma and urinary neopterin and total neopterin (neopterin + 7,8-dihydroneopterin) values were measured.Results: Neopterin and total neopterin were significantly elevated in urine and plasma for multiple days in sepsis versus non-sepsis patients. Plasma neopterin and total neopterin have decreasing relationships with increased eGFR (p<0.008 and p<0.001, respectively). Plasma/urinary neopterin and total neopterin ratios demonstrate that total neopterin flux is more influenced by eGFR than neopterin, with significantce of p<0.02 and p<0.0002 respectively.Conclusion: Sepsis patients present with greater levels of oxidative stress and immune system activation than non-sepsis patients of equal levels of trauma, as measured by neopterin and total neopterin. eGFR may need to be taken into account when accessing the level of inflammation from urinary neopterin measurements.


Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1681
Author(s):  
Lucia Sophie Kilian ◽  
Derk Frank ◽  
Ashraf Yusuf Rangrez

Chronic inflammation, the activation of immune cells and their cross-talk with cardiomyocytes in the pathogenesis and progression of heart diseases has long been overlooked. However, with the latest research developments, it is increasingly accepted that a vicious cycle exists where cardiomyocytes release cardiocrine signaling molecules that spiral down to immune cell activation and chronic state of low-level inflammation. For example, cardiocrine molecules released from injured or stressed cardiomyocytes can stimulate macrophages, dendritic cells, neutrophils and even T-cells, which then subsequently increase cardiac inflammation by co-stimulation and positive feedback loops. One of the key proteins involved in stress-mediated cardiomyocyte signal transduction is a small GTPase RhoA. Importantly, the regulation of RhoA activation is critical for effective immune cell response and is being considered as one of the potential therapeutic targets in many immune-cell-mediated inflammatory diseases. In this review we provide an update on the role of RhoA at the juncture of immune cell activation, inflammation and cardiac disease.


Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1413
Author(s):  
Sofia Ojasalo ◽  
Petteri Piskunen ◽  
Boxuan Shen ◽  
Mauri A. Kostiainen ◽  
Veikko Linko

Viruses are among the most intriguing nanostructures found in nature. Their atomically precise shapes and unique biological properties, especially in protecting and transferring genetic information, have enabled a plethora of biomedical applications. On the other hand, structural DNA nanotechnology has recently emerged as a highly useful tool to create programmable nanoscale structures. They can be extended to user defined devices to exhibit a wide range of static, as well as dynamic functions. In this review, we feature the recent development of virus-DNA hybrid materials. Such structures exhibit the best features of both worlds by combining the biological properties of viruses with the highly controlled assembly properties of DNA. We present how the DNA shapes can act as “structured” genomic material and direct the formation of virus capsid proteins or be encapsulated inside symmetrical capsids. Tobacco mosaic virus-DNA hybrids are discussed as the examples of dynamic systems and directed formation of conjugates. Finally, we highlight virus-mimicking approaches based on lipid- and protein-coated DNA structures that may elicit enhanced stability, immunocompatibility and delivery properties. This development also paves the way for DNA-based vaccines as the programmable nano-objects can be used for controlling immune cell activation.


Author(s):  
Lorena P. Suarez-Kelly ◽  
Steven H. Sun ◽  
Casey Ren ◽  
Isaac V. Rampersaud ◽  
David Albertson ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Boris Guennewig ◽  
Julia Lim ◽  
Lee Marshall ◽  
Andrew N. McCorkindale ◽  
Patrick J. Paasila ◽  
...  

AbstractTau pathology in Alzheimer’s disease (AD) spreads in a predictable pattern that corresponds with disease symptoms and severity. At post-mortem there are cortical regions that range from mildly to severely affected by tau pathology and neuronal loss. A comparison of the molecular signatures of these differentially affected areas within cases and between cases and controls may allow the temporal modelling of disease progression. Here we used RNA sequencing to explore differential gene expression in the mildly affected primary visual cortex and moderately affected precuneus of ten age-, gender- and RNA quality-matched post-mortem brains from AD patients and healthy controls. The two regions in AD cases had similar transcriptomic signatures but there were broader abnormalities in the precuneus consistent with the greater tau load. Both regions were characterised by upregulation of immune-related genes such as those encoding triggering receptor expressed on myeloid cells 2 and membrane spanning 4-domains A6A and milder changes in insulin/IGF1 signalling. The precuneus in AD was also characterised by changes in vesicle secretion and downregulation of the interneuronal subtype marker, somatostatin. The ‘early’ AD transcriptome is characterised by perturbations in synaptic vesicle secretion on a background of neuroimmune dysfunction. In particular, the synaptic deficits that characterise AD may begin with the somatostatin division of inhibitory neurotransmission.


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