scholarly journals The Gut Microbiome as a Component of the Gut–Brain Axis in Cognitive Health

2020 ◽  
Vol 22 (4) ◽  
pp. 485-494
Author(s):  
Wen Gao ◽  
Kelley L. Baumgartel ◽  
Sheila A. Alexander

Introduction: The human microbiome, the microorganisms living in and on the body, plays a vital role in brain physiology and pathophysiology. The gut microbiome (GMB) has been identified as a link in the gut–brain axis moderating cognitive development and health. Objectives: The objectives of this scoping review are to discuss mechanisms of the microbiome–gut–brain axis in cognition, review the existing literature on the GMB and cognition, and discuss implications for nursing research. Methods: We searched Pubmed using the terms “gut microbiome,” “brain,” and “cognition” and the terms “gut brain axis,” “microbiome,” and “cognition”; removed duplicates, studies not published in English, and unrelated publications; and added additional articles identified through references. We retained the 85 most relevant publications for this review. Results: Common themes in the current literature include GMB components; interactions on cognitive development; effects of GMB–gut–brain interactions on cognition, mild cognitive impairment and Alzheimer’s disease; effects of GMB interactions with physiologic stress on cognition in critical care; and GMB modification for improved cognition. Review of the literature on each of these topics reveals multiple theoretical mechanisms of action for GMB–gut–brain interaction that modify cognitive development and function across the lifespan. Discussion: GMB components and dysbiosis have been implicated in many cognitive states, and specific microbiota constituents contribute to cognitive development, stability, and impairment. The study of these interactions is relevant to nursing research as it addresses the holistic human experience and microbiome constituents are modifiable, facilitating translation into the clinical setting.

Hypertension ◽  
2020 ◽  
Vol 76 (Suppl_1) ◽  
Author(s):  
Robert M Bryan ◽  
Sharon C Phillips ◽  
David J Durgan

In recent years, it has become apparent that the gut microbiome can influence the functioning and pathological states of organs and systems throughout the body. In this study we tested the hypothesis that the gut microbiome has a major role in the cascade of pathological events, including inflammation and hypertension, leading to the onset of cerebral small vessel disease (CSVD). To test this hypothesis, we used an animal model for hypertensive CSVD, the spontaneously hypertensive stroke prone rat (SHRSP). At birth, SHRSP pups were placed with foster dams of the SHRSP strain or dams of the WKY strain, the control strain that does not develop hypertensive CSVD. Similarly, WKY pups were placed with dams of the same or opposite strain. The rationale for cross fostering is that gut microbiomes are shaped by environmental bacteria of the foster dam and the nesting surroundings. Analysis of the bacterial genera in feces using 16S rRNA analysis demonstrated that the gut microbiome in the rat pups was strongly influenced by the foster dam. SHRSP offspring fostered on WKY dams had systolic blood pressures (SBPs) that were significantly decreased by 26 mmHg (P<0.001, N=5-7/group) at 20 weeks, compared to SHRSP offspring fostered on SHRSP dams. Similarly, WKY offspring fostered on SHRSP dams had significantly increased SBP compared to WKY offspring fostered on WKY dams, although the magnitude of SBP change was not as robust (9 mmHg, P<0.05, N=6-8/group). At ~20 weeks of age, rats fostered on SHRSP dams showed increased expression of IL-1a, TLR-2, E-CAD, Muc-2, and Il-17a in ileum regardless of the strain of the offspring (N=6/group, P<0.05). Loss of blood-brain barrier (BBB) integrity, an early marker of CSVD onset, was assessed by extravasation of IgG, which is confined to the plasma space under normal conditions. Extravasation of IgG was increased four-fold in SHRSP fostered on SHRSP dams compared to WKY rats fostered on WKY dams; however, extravasation of IgG was decreased in SHRSP fostered on WKY dams by ~ 50% (P=0.005, N=5/group). These findings demonstrate that although SHRSP is a genetic model for CSVD, the makeup of the gut microbiota has a major influence on gut and brain physiology, and ultimately in shaping the phenotype and onset of CSVD.


Author(s):  
Genevieve L. Coe ◽  
Nicholas V. Pinkham ◽  
Arianna I. Celis ◽  
Christina Johnson ◽  
Jennifer L. DuBois ◽  
...  

Iron is an essential micronutrient for life. In mammals, dietary iron is primarily absorbed in the small intestine. Currently, the impacts of dietary iron on the taxonomic structure and function of the gut microbiome and reciprocal effects on the animal host are not well understood. Here, we establish a mouse model of low-iron challenge in which intestinal biomarkers and reduced fecal iron reveal iron stress while serum iron and mouse behavioral markers indicate maintenance of iron homeostasis. We show that the diversity of the gut microbiome in conventional C57BL/6 mice changes dramatically during two-weeks on a low-iron diet. We also show the effects of a low-iron diet on microbiome diversity are long-lasting and not easily recovered when iron is returned to the diet. Finally, after optimizing taxon association methods, we show that some bacteria are unable to fully recover after the low-iron challenge and appear to be extirpated from the gut entirely. In particular, OTUs from the Prevotellaceae and Porphyromonadaceae families and Bacteroidales order are highly sensitive to low-iron conditions, while other seemingly insensitive OTUs recover. These results provide new insights into the iron requirements of gut microbiome members and add to the growing understanding of mammalian iron cycling. IMPORTANCE All cells need iron. Both too much iron and too little lead to diseases and unwanted outcomes. Although the impact of dietary iron on human cells and tissues has been well studied, there is currently a lack of understanding about how different levels of iron influence the abundant and diverse members of the human microbiome. This study develops a well-characterized mouse model for studying low-iron levels and identifies key groups of bacteria that are most affected. We found that the microbiome undergoes large changes when iron is removed from the diet but that many individual bacteria are able to rebound when iron levels are changed by to normal. That said, a select few members, referred to as “iron-sensitive” bacteria seem to be lost. This study begins to identify individual members of the mammalian microbiome most affected by changes in dietary iron levels.


2021 ◽  
Vol 7 (1) ◽  
pp. 200-222
Author(s):  
S. Bulgakova ◽  
N. Zakharova ◽  
P. Romanchuk

In studies Romanchuk N. P. from invention in 2010 (A method for producing a cereal component for an instant food product and a method for producing a functional instant food product. RF patent for invention №2423873, consisting in increasing the preventive effect on the human body through the introduction of vital food substances into a functional food product to suppress free radical activity, invasive detoxification of the human body, optimizing neurogenic regulation of vascular tone in arterial hypertension and restoring reproductive functions in males and females by optimizing the quality structure of product components), to the present (https://doi.org/10.33619/2414-2948/58/14) it has been shown that a new managed healthy biomicrobiota and personalized functional and balanced nutrition of the “brain and microbiota” is a long-term medical program of the patient, which allows the combined use of nutritional epigenetics and pharmaceuticals, and most importantly the prevention of polypharmacy. The main engine of human longevity is when microbiological memory remains stable, and the diet of functional (healthy) dietary nutrition and the structure of healthy biomicrobiota function almost unchanged. The human microbiome is a collection of all microbes that inhabit the body. The human gut microbiome is a unique collection of microorganisms that affect a number of important processes: from metabolic and immune to cognitive, and deviation of its composition from the norm leads to the development of various pathological conditions. Harmful changes in the composition or number of gut bacteria, commonly referred to as intestinal dysbacteriosis, have been associated with the development and progression of numerous diseases, including cardiovascular (CVD) diseases. Most CVD risk factors, including aging, obesity, certain dietary patterns, and sedentary lifestyles, have been shown to cause bowel dysbiosis. Dysbacteriosis is associated with gut inflammation and reduced gut barrier integrity, which in turn increases levels of circulating structural components of bacteria and microbial metabolites that may contribute to CVD development. The purpose of the present review is to summarize available data on the role of the gut microbiome in the regulation of cardiovascular function and pathological processes. Particular attention is paid to dietary-related microbiome changes, as well as cellular mechanisms by which the microbiome can alter CVD risk.


mSystems ◽  
2020 ◽  
Vol 5 (5) ◽  
Author(s):  
Lauren M. Brinkac ◽  
Nandita Rahman ◽  
Loun-Loun Chua ◽  
Sterling Thomas

ABSTRACT The human gut microbiome plays a vital role in both health and disease states and as a mediator of cognitive and physical performance. Despite major advances in our understanding of the role of gut microbes in host physiology, mechanisms underlying human-microbiome dynamics have yet to be fully elucidated. This knowledge gap represents a major hurdle to the development of targeted gut microbiome solutions influencing human health and performance outcomes. The microbiome as it relates to warfighter health and performance is of interest to the Department of Defense (DoD) with the development of interventions impacting gut microbiome resiliency among its top research priorities. While technological advancements are enabling the development of experimental model systems that facilitate mechanistic insights underpinning human health, disease, and performance, translatability to human outcomes is still questionable. This review discusses some of the drivers influencing the DoD’s interest in the warfighter gut microbiome and describes current in vitro gut model systems supporting direct microbial-host interactions.


2021 ◽  
Vol 5 (4) ◽  
pp. 207-219
Author(s):  
Anasnasiia Ivanova ◽  
Olena Yalovenko ◽  
Alexey Dugan

The undeniable achievement in the study of the gut microbiome as an association of different microorganisms, including viruses, that colonize various organs and systems of the body, is the establishment of the fact that some diseases that were consmicrobiotaidered as non-infectious can also be transmitted through microorganisms. This resulted in the gut microbiome being called a forgotten organ that could serve as an additional and kind of missing link for a more objective and better diagnosis and treatment of many diseases that were not considered infectious. The rapid development of gut microbiome research in recent years not only is connected with better understanding of the functioning of the microbiome by the scientific community, but also inseparable from the strategic support of each country. Global investment in researches, related to the human microbiome, has exceeded $1.7 billion over the past decade. These researches contribute to the development of new diagnostic methods and therapeutic interventions. Our review is dedicated to the analysis of the possibilities of application of the human gut microbiome for the diagnosis of diseases, and the role of the intestines in the provocation and causing of certain diseases. Significant differences in the composition and diversity of the human microbiome are shown depending on geographical location and the change of socio-economic formations towards a gradual decrease in the diversity of the gut microbiome due to three stages of human population’s existence: food production, agriculture and industrial urban life. We analyze the influence of dietary patterns, various diseases (including malignant neoplasms) and viral infections (in particular, coronavirus) on the gut microbiome. And vice versa – the influence of the gut microbiome on the drugs effect and their metabolism, which affects the host's immune response and course of the disease.


2020 ◽  
Vol 27 (3) ◽  
pp. 201-209
Author(s):  
Syed Saqib Ali ◽  
Mohammad Khalid Zia ◽  
Tooba Siddiqui ◽  
Haseeb Ahsan ◽  
Fahim Halim Khan

Background: Ascorbic acid is a classic dietary antioxidant which plays an important role in the body of human beings. It is commonly found in various foods as well as taken as dietary supplement. Objective: The plasma ascorbic acid concentration may range from low, as in chronic or acute oxidative stress to high if delivered intravenously during cancer treatment. Sheep alpha-2- macroglobulin (α2M), a human α2M homologue is a large tetrameric glycoprotein of 630 kDa with antiproteinase activity, found in sheep’s blood. Methods: In the present study, the interaction of ascorbic acid with alpha-2-macroglobulin was explored in the presence of visible light by utilizing various spectroscopic techniques and isothermal titration calorimetry (ITC). Results: UV-vis and fluorescence spectroscopy suggests the formation of a complex between ascorbic acid and α2M apparent by increased absorbance and decreased fluorescence. Secondary structural changes in the α2M were investigated by CD and FT-IR spectroscopy. Our findings suggest the induction of subtle conformational changes in α2M induced by ascorbic acid. Thermodynamics signatures of ascorbic acid and α2M interaction indicate that the binding is an enthalpy-driven process. Conclusion: It is possible that ascorbic acid binds and compromises antiproteinase activity of α2M by inducing changes in the secondary structure of the protein.


Author(s):  
Steven N. Dworkin

This book describes the linguistic structures that constitute Medieval or Old Spanish as preserved in texts written prior to the beginning of the sixteenth century. It emphasizes those structures that contrast with the modern standard language. Chapter 1 presents methodological issues raised by the study of a language preserved only in written sources. Chapter 2 examines questions involved in reconstructing the sound system of Old Spanish before discussing relevant phonetic and phonological details. The chapter ends with an overview of Old Spanish spelling practices. Chapter 3 presents in some detail the nominal, verbal, and pronominal morphology of the language, with attention to regional variants. Chapter 4 describes selected syntactic structures, with emphasis on the noun phrase, verb phrase, object pronoun placement, subject-verb-object word order, verb tense, aspect, and mood. Chapter 5 begins with an extensive list of Old Spanish nouns, adjectives, verbs, and function words that have not survived into the modern standard language. It then presents examples of coexisting variants (doublets) and changes of meaning, and finishes with an overview of the creation of neologisms in the medieval language through derivational morphology (prefixation, suffixation, compounding). The book concludes with an anthology composed of three extracts from Spanish prose texts, one each from the thirteenth, fourteenth, and fifteenth centuries. The extracts contain footnotes that highlight relevant morphological, syntactic, and lexical features, with cross references to the relevant sections in the body of the book.


2021 ◽  
Vol 22 (15) ◽  
pp. 7931
Author(s):  
Ning Liu ◽  
Shiqiang Sun ◽  
Pengjie Wang ◽  
Yanan Sun ◽  
Qingjuan Hu ◽  
...  

Serotonin, also known as 5-hydroxytryptamine (5-HT), is a metabolite of tryptophan and is reported to modulate the development and neurogenesis of the enteric nervous system, gut motility, secretion, inflammation, sensation, and epithelial development. Approximately 95% of 5-HT in the body is synthesized and secreted by enterochromaffin (EC) cells, the most common type of neuroendocrine cells in the gastrointestinal (GI) tract, through sensing signals from the intestinal lumen and the circulatory system. Gut microbiota, nutrients, and hormones are the main factors that play a vital role in regulating 5-HT secretion by EC cells. Apart from being an important neurotransmitter and a paracrine signaling molecule in the gut, gut-derived 5-HT was also shown to exert other biological functions (in autism and depression) far beyond the gut. Moreover, studies conducted on the regulation of 5-HT in the immune system demonstrated that 5-HT exerts anti-inflammatory and proinflammatory effects on the gut by binding to different receptors under intestinal inflammatory conditions. Understanding the regulatory mechanisms through which 5-HT participates in cell metabolism and physiology can provide potential therapeutic strategies for treating intestinal diseases. Herein, we review recent evidence to recapitulate the mechanisms of synthesis, secretion, regulation, and biofunction of 5-HT to improve the nutrition and health of humans.


2021 ◽  
Vol 22 (3) ◽  
pp. 1416
Author(s):  
Riccardo Castagnoli ◽  
Francesca Pala ◽  
Marita Bosticardo ◽  
Amelia Licari ◽  
Ottavia M. Delmonte ◽  
...  

Inborn errors of immunity (IEI) are a group of disorders that are mostly caused by genetic mutations affecting immune host defense and immune regulation. Although IEI present with a wide spectrum of clinical features, in about one third of them various degrees of gastrointestinal (GI) involvement have been described and for some IEI the GI manifestations represent the main and peculiar clinical feature. The microbiome plays critical roles in the education and function of the host’s innate and adaptive immune system, and imbalances in microbiota-immunity interactions can contribute to intestinal pathogenesis. Microbial dysbiosis combined to the impairment of immunosurveillance and immune dysfunction in IEI, may favor mucosal permeability and lead to inflammation. Here we review how immune homeostasis between commensals and the host is established in the gut, and how these mechanisms can be disrupted in the context of primary immunodeficiencies. Additionally, we highlight key aspects of the first studies on gut microbiome in patients affected by IEI and discuss how gut microbiome could be harnessed as a therapeutic approach in these diseases.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Deepthi. R ◽  
Vandana Rani M ◽  
Delvin T. Robin ◽  
Anusree Dileep

AbstractThe science of Ayurveda with its strong and unique fundamentals holds its domain forever amidst all scientific and medical advancements. The concept of Shadkriyakala (the different phases of disease formation) holds relevance in preventive medicine and public health management as it provides ample chance to halt the disease process at each stage by timely intervention. In this review, we would like to bring to the limelight the relevance of Ritucharya (seasonal regimen) in primary prevention by modulating the gut microbiota. The modern gut microbiome researches now help us to better explore the Ayurveda theories of Agni (digestive fire) and Ama (metabolic toxins) preached centuries back. Ayurveda firmly proclaims that no disease ever arises without the derangement of Agni (digestive fire). The whole preventive and treatment methodology in Ayurveda focuses upon the modulation and management of “Agni” (digestive fire). When the functioning of Agni is deranged, Ama (metabolic toxin) is produced and it vitiates the doshas which spread throughout the body and manifest as varied diseases. A biomedical perspective of our reviews suggests that dysbiosis of microbial flora can cause a leaky gut by which the toxins of deranged digestive metabolism enter the bloodstream. Consequently, an inflammatory response occurs within the body which expresses out as diseases opportunistically. We meticulously reviewed the influence of extrinsic factors namely diet and climate on human gut microbiota, and our analysis emphasises the application prospects of Ritucharya (seasonal regimen), in regulating the dynamic host-microbe interaction.


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