Possible correlation between gut microbiota and immunity among healthy middle-aged and elderly people in southwest China

Influence of human gut microbiome on the healthy and the neurodegenerative aging

The gut microbiome plays a crucial role in host health throughout the lifespan by influencing brain function during aging. The microbial diversity of the human gut microbiome decreases during the aging process and, as a consequence, several mechanisms increase, such as oxidative stress, mitochondrial dysfunction, inflammatory response, and microbial gut dysbiosis. Moreover, evidence indicates that aging and neurodegeneration are closely related; consequently, the gut microbiome may serve as a novel marker of lifespan in the elderly. In this narrative study, we investigated how the changes in the composition of the gut microbiome that occur in aging influence to various neuropathological disorders, such as mild cognitive impairment (MCI), dementia, Alzheimer's disease (AD), and Parkinson's disease (PD); and which are the possible mechanisms that govern the relationship between the gut microbiome and cognitive impairment. In addition, several studies suggest that the gut microbiome may be a potential novel target to improve hallmarks of brain aging and to promote healthy cognition; therefore, current and future therapeutic interventions have been also reviewed.

Targeting Nrf2 by bioactive peptides alleviate inflammation: expanding the role of gut microbiota and metabolites

Inflammation is a complex process that usually refers to the general response of the body to the harmful stimuli of various pathogens, tissue damage, or exogenous pollutants. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that regulates cellular defense against oxidative damage and toxicity by expressing genes related to oxidative stress response and drug detoxification. In addition to its antioxidant properties, Nrf2 is involved in many other important physiological processes, including inflammation and metabolism. Nrf2 can bind the promoters of antioxidant genes and upregulates their expressions, which alleviate oxidation-induced inflammation. Nrf2 has been shown to upregulate heme oxygenase-1 expression, which promotes NF-κB activation and is closely related with inflammation. Nrf2, as a key factor in antioxidant response, is closely related to the expressions of pro-inflammatory factors, NF-κB pathway and cell metabolism. Bioactive peptides come from a wide range of sources and have many biological functions. Increasing evidence indicates that bioactive peptides have potential anti-inflammatory activities. This article summarized the sources, absorption and utilization of bioactive peptides and their role in alleviating inflammation via Nrf2 pathway. Bioactive peptides can also regulate gut microbiota and alter metabolites, which regulates the Nrf2 pathway through novel pathway and supplement the anti-inflammatory mechanisms of bioactive peptides. This review provides a reference for further study on the anti-inflammatory effect of bioactive peptides and the development and utilization of functional foods.

Mendelian randomization reveals association of gut microbiota with Henoch-Schönlein purpura and immune thrombocytopenia

Gut microbiota have been linked to immune thrombocytopenia (ITP) and Henoch-Schönlein purpura (HSP) in recent studies, but a cause-and-effect relationship is unclear. We used Mendelian randomization (MR) to assess causal relationships between gut microbiota and HSP/ITP using summary statistics from the GWAS dataset of the international MiBioGen and FinnGen consortium. The IVW method was used as the main evaluation indicator. MR analysis of 196 intestinal flora and HSP/ITP/sTP phenotypes showed that 12 flora were potentially causally associated with ITP, 6 with HSP, and 9 with sTP. The genes predicted that genus Coprococcus3 (p = 0.0264, OR = 2.05, 95% CI 1.09-3.88)and genus Gordonibacter (p = 0.0073, OR = 1.38; 95% CI 1.09-1.75) were linked to a higher likelihood of developing ITP. Additionally, family Actinomycetaceae (p = 0.02, OR = 0.51, 95% CI 0.28-0.90) and order Actinomycetales (p = 0.0199, OR = 0.50, 95% CI 0.28-0.90) linked to reduced HSP risk. Genus Ruminococcaceae UCG013 (p = 0.0426, OR = 0.44, 95% CI 0.20-0.97) negatively correlated with sTP risk. Our MR analyses offer evidence of a possible cause-and-effect connection between certain gut microbiota species and the likelihood of HSP/ITP.

Could the gut microbiota be capable of making individuals more or less susceptible to environmental toxicants?

Environmental toxicants are chemical substances capable to impair environmental quality and exert adverse effects on humans and other animals. The main routes of exposure to these pollutants are through the respiratory tract, skin, and oral ingestion. When ingested orally, they will encounter trillions of microorganisms that live in a community - the gut microbiota (GM). While pollutants can disrupt the GM balance, GM plays an essential role in the metabolism and bioavailability of these chemical compounds. Under physiological conditions, strategies used by the GM for metabolism and/or excretion of xenobiotics include reductive and hydrolytic transformations, lyase and functional group transfer reactions, and enzyme-mediated functional transformations. Simultaneously, the host performs metabolic processes based mainly on conjugation, oxidation, and hydrolysis reactions. Thus, due to the broad variety of bacterial enzymes present in GM, the repertoire of microbial transformations of chemicals is considered a key component of the machinery involved in the metabolism of pollutants in humans and other mammals. Among pollutants, metals deserve special attention once contamination by metals is a worldwide problem, and their adverse effects can be observed even at very low concentrations due to their toxic properties. In this review, bidirectional interaction between lead, arsenic, cadmium, and mercury and the host organism and its GM will be discussed given the most recent literature, presenting an analysis of the ability of GM to alter the host organism's susceptibility to the toxic effects of heavy metals, as well as evaluating the extent to which interventions targeting the microbiota could be potential initiatives to mitigate the adverse effects resulting from poisoning by heavy metals. This study is the first to highlight the overlap between some of the bacteria found to be altered by metal exposure and the bacteria that also aid the host organism in the metabolism of these metals. This could be a key factor to determine the beneficial species able to minimize the toxicity of metals in future therapeutic approaches.

The human gut microbiome and aging

The composition of the human gut microbiome has been observed to change over the course of an individual's life. From birth, it is shaped by mode of delivery, diet, environmental exposures, geographic location, exposures to medications, and by aging itself. Here, we present a narrative review of the gut microbiome across the lifespan with a focus on its impacts on aging and age-related diseases in humans. We will describe how it is shaped, and features of the gut microbiome that have been associated with diseases at different phases of life and how this can adversely affect healthy aging. Across the lifespan, and especially in old age, a diverse microbiome that includes organisms suspected to produce anti-inflammatory metabolites such as short-chain fatty acids, has been reported to be associated with healthy aging. These findings have been remarkably consistent across geographic regions of the world suggesting that they could be universal features of healthy aging across all cultures and genetic backgrounds. Exactly how these features of the microbiome affect biologic processes associated with aging thus promoting healthy aging will be crucial to targeting the gut microbiome for interventions that will support health and longevity.

Tripterygium hypoglaucum extract ameliorates adjuvant-induced arthritis in mice through the gut microbiota

Traditionally, Tripterygium hypoglaucum (Levl.) Hutch (THH) are widely used in Chinese folk to treat rheumatoid arthritis (RA). This study aimed to investigate whether the anti-RA effect of THH is related with the gut microbiota. The main components of prepared THH extract were identified by HPLC-MS. C57BL/6 mice with adjuvant-induced arthritis (AIA) were treated with THH extract by gavage for one month. THH extract significantly alleviated swollen ankle, joint cavity exudation, and articular cartilage destruction in AIA mice. The mRNA and protein levels of inflammatory mediators in muscles and plasma indicated that THH extract attenuated inflammatory responses in the joint by blocking TLR4/MyD88/MAPK signaling pathways. THH extract remarkably restored the dysbiosis of the gut microbiota in AIA mice, featuring the increases of Bifidobacterium, Akkermansia, and Lactobacillus and the decreases of Butyricimonas, Parabacteroides, and Anaeroplasma. Furthermore, the altered bacteria were closely correlated with physiological indices and drove metabolic changes of the intestinal microbiota. In addition, antibiotic-induced pseudo germ-free mice were employed to verify the role of the intestinal flora. Strikingly, THH treatment failed to ameliorate the arthritis symptoms and signaling pathways in pseudo germ-free mice, which validates the indispensable role of the intestinal flora. For the first time, we demonstrated that THH extract protects joint inflammation by manipulating the intestinal flora and regulating the TLR4/MyD88/MAPK signaling pathway. Therefore, THH extract may serve as a microbial modulator to recover RA in clincial practice.ver RA in clincial practice.

Gut Microbiota is an Impact Factor based on the Brain-Gut Axis to Alzheimer's Disease: A Systematic Review

Alzheimer's disease (AD) is a degenerative disease of the central nervous system. The pathogenesis of AD has been explained using cholinergic, β-amyloid toxicity, tau protein hyperphosphorylation, and oxidative stress theories. However, an effective treatment method has not been developed. In recent years, with the discovery of the brain-gut axis (BGA) and breakthroughs made in Parkinson's disease, depression, autism, and other diseases, BGA has become a hotspot in AD research. Several studies have shown that gut microbiota can affect the brain and behavior of patients with AD, especially their cognitive function. Animal models, fecal microbiota transplantation, and probiotic intervention also provide evidence regarding the correlation between gut microbiota and AD. This article discusses the relationship and related mechanisms between gut microbiota and AD based on BGA to provide possible strategies for preventing or alleviating AD symptoms by regulating gut microbiota.

Exploring the Relationship between the Gut Microbiota and Ageing: A Possible Age Modulator

The gut microbiota (GM) has been the subject of intense research in recent years. Therefore, numerous factors affecting its composition have been thoroughly examined, and with them, their function and role in the individual's systems. The gut microbiota's taxonomical composition dramatically impacts older adults' health status. In this regard, it could either extend their life expectancy via the modulation of metabolic processes and the immune system or, in the case of dysbiosis, predispose them to age-related diseases, including bowel inflammatory and musculoskeletal diseases and metabolic and neurological disorders. In general, the microbiome of the elderly tends to present taxonomic and functional changes, which can function as a target to modulate the microbiota and improve the health of this population. The GM of centenarians is unique, with the faculty-promoting metabolic pathways capable of preventing and counteracting the different processes associated with age-related diseases. The molecular mechanisms by which the microbiota can exhibit anti-ageing properties are mainly based on anti-inflammatory and antioxidant actions. This review focuses on analysing the current knowledge of gut microbiota characteristics and modifiers, its relationship with ageing, and the GM-modulating approaches to increase life expectancy.

Alteration in Gut Microbiota Composition of Older Adults Is Associated with Obesity and Its Indices: A Systematic Review

BACKGROUND

Obesity in the older adults is a health concern that increases the risk of several life-threatening diseases. Previous research has been revealed that alterations in the gut microbiota composition is related to obesity. So, understanding the gut microbiota changes in older adults' obesity may help to provide promising strategies for their health management.

OBJECTIVES

Here we conducted a systematic review that investigate the alteration of gut microbiota composition in association with obesity and its indices in the older adults.

DESIGN

Systematic review.

SETTING

A comprehensive systematic search was performed through PubMed, Web of Science, Scopus and Embase databases for all relative studies up to 2023 with the main search concepts as Microbiota, Obesity and Elderly. The data about gut microbiota in association with obesity indices had been extracted.

PARTICIPANTS

Older adults (≥60 years).

INTERVENTION

None.

MEASUREMENTS

None.

RESULTS

Within 10741 recordes, 11 studies met the inclusion criteria and were included in this systematic review. Most of them indicated the gut microbiota alterations in obese compared with non-obese older adults. However, the gut microbiome composition in obese older adults is affected by other underlying diseases like diabetes and metabolic syndrome. The most important taxa that had abundance alteration in association with obesity in older adults were Christensenellaceae, Porphyromonadaceae and Rikenellaceae, Akkermansia, Blautia, Prevotella, Ruminococcus, Bacteroides and Faecalibacterium.

CONCLUSION

The gut microbiota composition is associated with obesity in older adults. Considering the other factors affecting the composition of gut microbiota, such as age, underlying diseases and lifestyle, a more accurate conclusion about this matter requires more future studies.

Effects of dog ownership on the gut microbiota of elderly owners

Dog owners are usually in close contact with dogs. Whether dogs can affect the gut microbiota of elderly dog owners is worth studying. Data from 54 elderly (over 65 years of age) dog owners were screened from the American Gut Project. Owning a dog did not affect the α-diversity of the gut microbiota of the dog owner. Dog ownership significantly modulated the composition of the gut microbiota of the dog owner. The abundance of Actinobacteria was significantly increased. The abundances of Bifidobacteriaceae and Ruminococcaceae were significantly increased, while the abundance of Moracellaceae was significantly suppressed. In general, dog ownership can regulate the composition of gut microbiota and has a more significant effect on elderly males.

Phyllanthus emblica (Amla) Fruit Powder as a Supplement to Improve Preweaning Dairy Calves' Health: Effect on Antioxidant Capacity, Immune Response, and Gut Bacterial Diversity

Disease is the main reason for the use of antimicrobials in calf rearing, and antibiotics are commonly used to treat calves, including for unknown diseases. This leads to antimicrobial resistance, which is a challenge to the livestock industry and public health. Plant products containing high levels of phytochemicals may improve the immunity and resistance of calves against infections, thereby reducing the use of antimicrobials. This study aimed to investigate the effect of Phyllanthus emblica (Amla) fruit powder (PE) supplementation on antioxidant capacity and immune response of preweaning dairy calves. One hundred, 2-day-old, male Holstein calves were randomly assigned into five treatment groups receiving 0, 5, 10, 20, and 40 g/d PE supplementation. Antioxidant and immune indices and pro- and anti-inflammatory cytokines were analyzed from serum samples, whereas 16S rRNA was analyzed from rumen fluid and fecal samples. PE supplementation, at 5 g/d, protected calves against oxidative stress and improved antioxidant enzymes and immune and anti-inflammatory responses, showing its immunity-enhancing and protective roles against infections. However, the antioxidant capacity and immune response decreased with increasing PE levels, illustrating the adverse effects of PE supplementation at higher doses. The analysis of ruminal and fecal bacterial community abundance detected higher proportions of Firmicutes at an early age, and a higher Bacteroidetes to Firmicutes ratio at weaning, in calves supplemented with 5 g/d PE. This contributed to the development of the immune system in early life, and improved immune and anti-inflammatory responses at a later age. The overall results suggest that PE could be supplemented at 5 g/d for preweaning dairy calves to protect against oxidative stress and infections while maintaining normal gut microbial hemostasis.

Clinical Biochemical Indicators and Intestinal Microbiota Testing Reveal the Influence of Reproductive Age Extending from the Mother to the Offspring

Age is an important factor that determines the physiological functions of the human body, but the changes in maternal physiology, biochemistry, and intestinal flora related to reproductive age and their impact on offspring are not clear. Here, we tested and analyzed the clinical physiological and biochemical indicators and/or intestinal flora, matching the data of 252 parturients and their newborns. We found that 4 clinical indicators, including the white blood cell count and the absolute value of monocytes, were significantly related to the reproductive age (P < 0.05). The composition of the intestinal flora also varied with age, and the intestinal flora of advanced-age women (≥35 years old) was different from that of middle-aged women (>25 and <35 years old). We also found that changes in maternal clinical physiological and biochemical indicators related to reproductive age could reflect changes in the abundance of bacteria, such as Peptococcus and Vibrio, and changes in the intestinal flora spread to offspring. These results provide new evidence to explain the increased adverse pregnancy outcomes of mothers of inappropriate age, describe the increased health risks of newborns, help us examine the importance of age-appropriate birth from a broader perspective, and contribute to the discovery of mother-child bonds for a better understanding of healthy reproduction. IMPORTANCE In this study, we demonstrated that physiological indicators and the gut microbiome fluctuate drastically among parturients of different reproductive ages and that there is a significant correlation between the two changes. Mothers of different ages had different gut microbes, and the gut microbiota varied as the childbearing age became too high. Changes in the gut microbiome with maternal reproductive age affected the offspring, and the influence of reproductive age on the intestinal flora had a synergistic effect between mother and child that was revealed for the first time. The maternal childbearing age might affect the colonization of the offspring's initial flora. The results provide new evidence to explain the increased adverse pregnancy outcomes of mothers of inappropriate age, describe the increased health risks of newborns, and contribute to the discovery of mother-child bonds for a better understanding of healthy reproduction.

Early Weaning and Milk Substitutes Affect the Gut Microbiome, Metabolomics, and Antibody Profile in Goat Kids Suffering From Diarrhea

Early weaning and milk substitutes increase the incidence of diarrhea in young ruminants, which may modify their gut microbiota, metabolism, immunity, and health. The aim of the study was to determine if early weaning and milk substitutes affect the gut microbiota, metabolism, and immunological status of goat kids suffering from diarrhea. The 16S rRNA gene and metagenomic sequencing in feces and serum metabolomics of early-weaned and artificially reared goat kids suffering from diarrhea (DK group) and healthy goat kids reared by their mothers (HK group) were analyzed. The serum biochemistry and immunoglobulin concentration were also determined. Several probiotics, such as Streptococcus and Lactobacillus, were higher in the feces of the DK group than in feces of the HK group. Ruminococcus sp. was elevated in the feces of HKs, likely being a biomarker for goat health. Taking all the carbohydrate-active enzyme (CAZyme) families into consideration, 20 CAZyme families were different between the groups. Compared with the DK group, the relative quantity of glycoside hydrolases (GH) and glycosyltransferase (GT) families in the HK group decreased. GT70 was only identified in HK kids participating in the activity of β-glucuronosyltransferase during the carbohydrate metabolism. Overall, 24 metabolites were different between the groups, which were mainly involved in protein digestion and absorption, cyanoamino acid metabolism, and cholesterol metabolism. The concentrations of immunoglobulins G and M were significantly lower in the DK than in the HK group. In conclusion, our study characterized the fecal microbiota, metabolism, and immunological status of early-weaned and artificially reared goat kids suffering from diarrhea.

Parishin From Gastrodia Elata Ameliorates Aging Phenotype in Mice in a Gut Microbiota-Related Manner

The physiological and pathological processes that accompany aging can seriously affect the quality of life of the elderly population. Therefore, delaying aging and developing antiaging products have become popular areas of inquiry. Gut microbiota plays an important role in age-related phenotypes. The present study aimed to investigate the antiaging effects and underlying mechanism of parishin, a phenolic glucoside isolated from traditional Chinese medicine Gastrodia elata. Samples from adult (12 weeks), low-dose (10 mg/kg/d) or high-dose (20 mg/kg/d) parishin-treated and untreated aged (19 months) mice were collected to determine blood indicators, gut microbiota and metabolome, and cardiopulmonary histopathological features. The results showed that parishin treatment ameliorates aging-induced cardiopulmonary fibrosis and increase in serum p16^Ink4a, GDF15, and IL-6 levels. Furthermore, parishin treatment alleviated dysbiosis in gut microbiota, including altered microbial diversity and the aberrant abundance of opportunistic pathogenic bacteria such as Turicibacter and Erysipelatoclostridium. Gene function prediction and gut metabolome analysis results indicated that the parishin treatment-altered gut microbiota played important roles in sugar, lipid, amino acid and nucleic acid metabolism, and improved gut metabolic disorders in aged mice. In conclusion, the present study provides an experimental basis of potential applications of parishin against aging.

Emerging Interrelationship Between the Gut Microbiome and Cellular Senescence in the Context of Aging and Disease: Perspectives and Therapeutic Opportunities

The significance of diversity, composition, and functional attributes of the gut microbiota in shaping human health is well recognized. Studies have shown that gut microbiota is closely linked to human aging, and changes in the gut microbiome can predict human survival and longevity. In addition, a causal relationship between gut microbiota dysbiosis and chronic age-related disorders is also becoming apparent. Recent advances in our understanding of the cellular and molecular aspects of biological aging have revealed a cellular senescence-centric view of the aging process. However, the association between the gut microbiome and cellular senescence is only beginning to be understood. The present review provides an integrative view of the evolving relationship between the gut microbiome and cellular senescence in aging and disease. Evidence relating to microbiome-mediated modulation of senescent cells, as well as senescent cells-mediated changes in intestinal homeostasis and diseases, have been discussed. Unanswered questions and future research directions have also been deliberated to truly ascertain the relationship between the gut microbiome and cellular senescence for developing microbiome-based age-delaying and longevity-promoting therapies.

Immune Memory in Aging: a Wide Perspective Covering Microbiota, Brain, Metabolism, and Epigenetics

Non-specific innate and antigen-specific adaptive immunological memories are vital evolutionary adaptations that confer long-lasting protection against a wide range of pathogens. Adaptive memory is established by memory T and B lymphocytes following the recognition of an antigen. On the other hand, innate immune memory, also called trained immunity, is imprinted in innate cells such as macrophages and natural killer cells through epigenetic and metabolic reprogramming. However, these mechanisms of memory generation and maintenance are compromised as organisms age. Almost all immune cell types, both mature cells and their progenitors, go through age-related changes concerning numbers and functions. The aging immune system renders the elderly highly susceptible to infections and incapable of mounting a proper immune response upon vaccinations. Besides the increased infectious burden, older individuals also have heightened risks of metabolic and neurodegenerative diseases, which have an immunological component. This review discusses how immune function, particularly the establishment and maintenance of innate and adaptive immunological memory, regulates and is regulated by epigenetics, metabolic processes, gut microbiota, and the central nervous system throughout life, with a focus on old age. We explain in-depth how epigenetics and cellular metabolism impact immune cell function and contribute or resist the aging process. Microbiota is intimately linked with the immune system of the human host, and therefore, plays an important role in immunological memory during both homeostasis and aging. The brain, which is not an immune-isolated organ despite former opinion, interacts with the peripheral immune cells, and the aging of both systems influences the health of each other. With all these in mind, we aimed to present a comprehensive view of the aging immune system and its consequences, especially in terms of immunological memory. The review also details the mechanisms of promising anti-aging interventions and highlights a few, namely, caloric restriction, physical exercise, metformin, and resveratrol, that impact multiple facets of the aging process, including the regulation of innate and adaptive immune memory. We propose that understanding aging as a complex phenomenon, with the immune system at the center role interacting with all the other tissues and systems, would allow for more effective anti-aging strategies.

Effect of Nutrition on Age-Related Metabolic Markers and the Gut Microbiota in Cats

Age-related changes in the gut microbiota and metabolites are associated with the increased risk of detrimental conditions also seen with age. This study evaluated whether a test food with potential anti-aging benefits results in favorable changes in plasma and fecal metabolites and the fecal microbiota in senior cats. Forty healthy domestic cats aged 8.3–13.5 years were fed a washout food for 30 days, then control or test food for 30 days. After another 30-day washout, cats were switched to the other study food for 30 days. Assessment of plasma and fecal metabolites showed lower levels of metabolites associated with detrimental processes (e.g., uremic toxins) and higher levels of metabolites associated with beneficial processes (e.g., tocopherols) after cats consumed the test food compared with the control food. A shift toward proteolysis with the control food is supported by higher levels of amino acid metabolites and lower levels of carbohydrate metabolites. Operational taxonomic units of greater abundance with the test food positively correlated with carbohydrate and nicotinic acid metabolites, and negatively correlated with uremic toxins, amino acid metabolism, secondary bile salts, and branched-chain fatty acids. Taken together, the test food appears to result in greater levels of metabolites and microbiota associated with a healthier state.

Abnormalities in Gut Microbiota and Metabolism in Patients With Chronic Spontaneous Urticaria

Background

Increasing evidence suggests that the gut microbiome plays a role in the pathogenesis of allergy and autoimmunity. The association between abnormalities in the gut microbiota and chronic spontaneous urticaria (CSU) remains largely undefined.

Methods

Fecal samples were obtained from 39 patients with CSU and 40 healthy controls (HCs). 16S ribosomal RNA (rRNA) gene sequencing (39 patients with CSU and 40 HCs) and untargeted metabolomics (12 patients with CSU and 12 HCs) were performed to analyze the compositional and metabolic alterations of the gut microbiome in CSU patients and HCs.

Results

The 16S rRNA gene sequencing results showed a significant difference in the β-diversity of the gut microbiota, presented as the Jaccard distance, between CSU patients and HCs. No significant differences were found in the α-diversity of the gut microbiota between patients and HCs. At the phylum level, the major bacteria in the gut microbiome of patients with CSU were Firmicutes, Bacteroidetes, Proteobacteria, and Actinobacteria. At the genus level, Lactobacillus, Turicibacter, and Lachnobacterium were significantly increased and Phascolarctobacterium was decreased in patients with CSU. PICRUSt and correlation analysis indicated that Lactobacillus, Turicibacter, and Phascolarctobacterium were positively related to G protein-coupled receptors. Metabolomic analysis showed that α-mangostin and glycyrrhizic acid were upregulated and that 3-indolepropionic acid, xanthine, and isobutyric acid were downregulated in patients with CSU. Correlation analysis between the intestinal microbiota and metabolites suggested that there was a positive correlation between Lachnobacterium and α-mangostin.

Conclusions

This study suggests that disturbances in the gut microbiome composition and metabolites and their crosstalk or interaction may participate in the pathogenesis of CSU.

The Aged Intestine: Performance and Rejuvenation

Owing to the growing elderly population, age-related problems are gaining increasing attention from the scientific community. With senescence, the intestine undergoes a spectrum of changes and infirmities that are likely the causes of overall aging. Therefore, identification of the aged intestine and the search for novel strategies to rescue it, are required. Although progress has been made in research on some components of the aged intestine, such as intestinal stem cells, the comprehensive understanding of intestinal aging is still limited, and this restricts the in-depth search for efficient strategies. In this concise review, we discuss several aspects of intestinal aging. More emphasis is placed on the appraisal of current and potential strategies to alleviate intestinal aging, as well as future targets to rejuvenate the aged intestine.

Association of Serum Immunoglobulins Levels With Specific Disease Phenotypes of Crohn's Disease: A Multicenter Analysis in China

Background and Aim: Serum immunoglobulins were reported to be associated with clinical characteristics of inflammatory bowel disease. However, whether a difference exists in the serum immunoglobulins levels in patients with Crohn's disease (CD) with different disease location and behavior phenotypes remains unclear. Therefore, this study aimed to explore the associations of serum immunoglobulins levels with specific CD phenotypes. Methods: Patients with CD having recorded serum immunoglobulins levels were recruited through multicenter collaborative efforts. The associations between serum immunoglobulins levels and distinct phenotypes of CD were evaluated using multiple logistic regression models. Results: A total of 608 patients with CD were included in the study. Elevated (above the upper limit of normal) serum immunoglobulin G (IgG), IgA, IgM, and IgG4 were identified in 24.5, 17.4, 2.1, and 8.2% of patients, respectively. Elevated serum IgG4 levels negatively correlated with complicated disease behavior [odds ratio (OR) 0.49, 95% confidence interval (CI) 0.26-0.92]. Elevated serum IgG was linked to isolated ileal disease with an OR of 0.37 (95% CI 0.23-0.61). The ORs of isolated ileal disease progressively reduced across increasing quartiles of IgG (P for trend < 0.001). The adjusted ORs of isolated ileal disease for increasing quartiles of IgM were 1.82 (1.07-3.1), 1.92 (1.14-3.24), 1.17 (0.69-1.98), and 1 (P for trend = 0.008). Besides, serum IgA and IgG levels significantly correlated with several disease activity indices. Conclusions: These results suggested that certain serum immunoglobulins were associated with specific disease phenotypes of CD. Further investigations to account for the associations are warranted.

Icariin enhances youth-like features by attenuating the declined gut microbiota in the aged mice

We previously reported the neuroprotective effects of icariin in rat cortical neurons. Here, we present a study on icariin's anti-aging effect in 24-month aged mice by treating them with a single daily dose of 100 mg/kg of icariin for 15 consecutive days. Icariin treatment improved motor coordination and learning skills while lowered oxidative stress biomarkers in the serum, brain, kidney, and liver of the aged mice. In addition, icariin improved the intestinal integrity of the aged mice by upregulating tight junction adhesion molecules and the Paneth and goblet cells, along with the reduction of iNOS and pro-inflammatory cytokines (IL-1β, TNF-α, IL-2 and IL-6, and IL-12). Icariin treatments also significantly upregulated aging-related signaling molecules, Sirt 1, 3 & 6, Pot1α, BUB1b, FOXO1, Ep300, ANXA3, Calb1, SNAP25, and BDNF in old mice. Through gut microbiota (GM) analysis, we observed icariin-associated improvements in GM composition of aged mice by reinstating bacteria found in the young mice, while suppressing some bacteria found in the untreated old mice. To clarify whether icariin's anti-aging effect is rooted in the GM, we performed fecal microbiota transfer (FMT) from icariin-treated old mice to the old mice. FMT-recipients exhibited similar improvements in the rotarod score and age-related biomarkers as observed in the icariin-treated old mice. Equal or better improvement on the youth-like features was noticed when aged mice were FMT with feces from young mice. Our study shows that both direct treatments with icariin and fecal transplant from the icariin-treated aged mice produce similar anti-aging phenotypes in the aged mice. We prove that GM plays a pivotal role in the healing abilities of icariin. Icariin has the potentials to be developed as a medicine for the wellness of the aged adults.

Cancer and Aging: Two Tightly Interconnected Biological Processes

Age is one of the main risk factors of cancer; several biological changes linked with the aging process can explain this. As our population is progressively aging, the proportion of older patients with cancer is increasing significantly. Due to the heterogeneity of general health and functional status amongst older persons, treatment of cancer is a major challenge in this vulnerable population. Older patients often experience more side effects of anticancer treatments. Over-treatment should be avoided to ensure an optimal quality of life. On the other hand, under-treatment due to fear of toxicity is a frequent problem and can lead to an increased risk of relapse and worse survival. There is a delicate balance between benefits of therapy and risk of toxicity. Robust biomarkers that reflect the body's biological age may aid in outlining optimal individual treatment regimens for older patients with cancer. In particular, the impact of age on systemic immunity and the tumor immune infiltrate should be considered, given the expanding role of immunotherapy in cancer treatment. In this review, we summarize current knowledge concerning the mechanistic connections between aging and cancer, as well as aging biomarkers that could be helpful in the field of geriatric oncology.

Different effects of nano- and microplastics on oxidative status and gut microbiota in the marine medaka Oryzias melastigma

Plastic is regarded as a major environmental concern. In particular, nanoplastics and microplastics (NMPs) are attracting global attention due to their potential impact on aquatic organisms. Here, we examined the effects of NMPs (50 nm polystyrene microbead nanoplastics [NPs] and 45 µm microplastics [MPs]) on oxidative status and gut microbiota in the marine medaka Oryzias melastigma. The NP-exposed group exhibited stronger oxidative stress with higher activation levels of antioxidants compared to the MP-exposed group. However, the MP-exposed group demonstrated induction of intestinal damage (e.g., increased mucus ratio) with further alterations of gut microbiota, compared to the NP-exposed group. In particular, MPs caused more significant alterations of microbiota composition at both phylum and genus levels. Thus, in this study we show distinct toxicity pathways of NPs and MPs, an oxidative stress-mediated pathway (e.g., antioxidants) induced by NP exposure and dysbiosis of gut microbiota in association with immune dysfunction induced by MP exposure. Our results are helpful for expanding our knowledge about the impacts of NMPs as potentially harmful substances in the aquatic environment.

Age-related changes of microbiota in midlife associated with reduced saccharolytic potential: an in vitro study

BACKGROUND

Gut microbiota is critical in maintaining human health, of which diversity and abundance are subject to significantly reduce in seniors. Gut microbiota is reported to be stable across the long adulthood in general, but lack of careful examination, especially for the midlife people.

RESULTS

To characterize the gut microbiota in midlife, we investigated the faecal microbiota between two groups of healthy people, young, 20-39 years old, n = 15; and midlife, 40-60 years old, n = 15. Metabolic responses of the microbiota were studied through in vitro batch fermentation model. Although no difference was observed in the diversity indices between the two age groups, a wide range taxonomic changes were found in the faecal microbiota. Furthermore, substantial Bifidobacterium reduction was also found in both faecal and fermented samples. The faecal SCFAs are similar in both groups, as well as starch fermentation broth. However, after inulin fermentation, the acetate concentration and inulin degradation rate decreased while the gas production increased in midlife group, suggesting a deficiency of saccharolytic potential in midlife, especially for non-digestible carbohydrate.

CONCLUSIONS

Our data demonstrate that gut microbiota begins to change as early as in midlife. The reduction in Bifidobacterium dominates the change of the microbiota composition in midlife resulting in attenuated saccharolytic capacity of inulin, possibly leading to insufficient acetate production which might be associated with healthy problems in this transition period from young to elderly.

Bacteroides, butyric acid and t10,c12-CLA changes in colorectal adenomatous polyp patients

BACKGROUND

Colorectal adenomatous polyps (CAPs) are considered precancerous lesions of colorectal cancer (CRC). The gut microbiota participates in the process of digestion and, in the process, produces metabolites, mainly short-chain fatty acids (SCFAs), secondary bile acids and conjugated linoleic acid (CLA). This study aimed to investigate the gut microbiota constituents and metabolites in the faeces of CAP patients to identify microbiota or metabolites that can be used as sensitive biological predictors and to provide a theoretical basis for the clinical treatment of CAPs.

METHODS

16S rRNA sequence analysis was used to detect microbial changes in the faeces of CAP patients. qPCR analysis was used to evaluate the ability of the microbiota to produce metabolites, and the contents of metabolites in faeces were detected by ion chromatography and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

RESULTS

Based on the detection of the gut microbiota, patients with CAPs had increased abundances of Bacteroides and Citrobacter, and the abundances of Weissella and Lactobacillus were decreased. We also explored gene expression, and the abundance of butyrate-producing bacterial genes was significantly increased in the faeces of CAP patients, but those of secondary bile acid-producing and CLA-producing bacterial genes showed no differences in faecal samples. The acetic acid and butyric acid contents were increased in the faeces of the CAP group, and the healthy control group had higher t10,c12-CLA contents.

CONCLUSION

The gut microbiota analysis results, assessed in faeces, showed that Bacteroides and Citrobacter were positively correlated with CAPs, which indicated that changes in specific genera might be detrimental to intestinal health. In addition, t10,c12-CLA played an important role in protecting the intestine.

Gut microbiota affect the formation of calcium oxalate renal calculi caused by high daily tea consumption

Kidney stones are a common and frequently occurring disease worldwide. Stones can cause urinary tract obstruction, pain, haematuria, and other symptoms. In this study, the relationship between calcium oxalate renal calculi and gut microbiota was considered. The dietary habits of 30 patients with calcium oxalate kidney stones and 30 healthy people were investigated. The 16S rDNA sequences and short-chain fatty acids (SCFAs) in their stool samples were analysed. We identified 5 genera of the gut microbiota as biomarkers for calcium oxalate renal calculi, namely, Bacteroides, Phascolarctobacterium, Faecalibacterium, Akkermansia, and Lactobacillus, with a receiver operating characteristic (ROC) curve value of 0.871 (95% confidence interval (CI) 0.785-0.957). Phascolarctobacterium and Faecalibacterium showed a positive relationship with SCFA synthesis to reduce the risk of kidney stones. Meanwhile, according to the analysis, Lactobacillus spp. made the largest contribution (79%) to prevent kidney stones caused by tea consumption, since tea offers the great parts of oxalate in kidney stone formation. Three strains of Lactobacillus spp. were isolated from stools of a healthy person with a high level of tea consumption who did not suffer from kidney stones. All these strains survived in the colon with supplementation of high concentrations of tea and efficiently degraded oxalic acid (Ca. 50%) in an in vitro colonic simulation. Therefore, a suitable adjustment of the gut microbiota or SCFA concentration enhanced the degradation of oxalate from food, which can be applied to prevent the formation of calcium oxalate renal calculi caused by tea. KEY POINTS: • Five genera, including Lactobacillus, were identified as biomarkers for calcium oxalate renal calculi. • Lactobacillus is a potential gut bacterium associated with preventing kidney stone formation. • Isolated Lactobacillus strains have the ability to degrade oxalic acid in vitro.

Nutraceuticals-Based Immunotherapeutic Concepts and Opportunities for the Mitigation of Cellular Senescence and Aging: A Narrative Review

The role of increased tissue senescent cell (SC) burden in driving the process of ageing and associated disorders is rapidly gaining attention. Amongst various plausible factors, impairment in immune functions is emerging as a critical regulator of known age-associated accumulation of SC. Immune cells dysfunctions with age are multi-faceted and are uniquely attributed to the independent processes of immunosenescence and cellular senescence which may collectively impair immune system mediated clearance of SC. Moreover, being functionally and phenotypically heterogenic, immune cells are also liable to be affected by senescence microenvironment in other tissues. Therefore, strategies aimed at improving immunosenescence and cellular senescence in immune cells can have pleiotropic effects on ageing physiology including the accumulation of SC. In this regard, nutraceutical's immunomodulatory attributes are well documented which may have implications in developing nutrition-oriented immunotherapeutic approaches against SC. In particular, the three diverse sources of bioactive ingredients, viz., phytochemicals, probiotic bacteria and omega-3-fatty acids have shown promising anti-immunosenescence and anti-cellular senescence potential in immune cells influencing aging and immunity in ways beyond modest stimulation of immune responses. The present narrative review describes the preventive and therapeutic attributes of phytochemicals such as polyphenols, probiotic microbes and omega-3-fatty acids in influencing the emerging nexus of immunosenescence, cellular senescence and SC during aging. Outstanding questions and nutraceuticals-based pro-longevity and niche research areas have been deliberated. Further research using integrative approaches is recommended for developing nutrition-based holistic immunotherapeutic strategies for 'healthy ageing'.

Immunoglobulin M in Health and Diseases: How Far Have We Come and What Next?

B lymphocytes are important in secreting antibodies that protect against invading pathogens such as viruses, bacteria, parasites, and also in mediating pathogenesis of allergic diseases and autoimmunity. B lymphocytes develop in the bone marrow and contain heavy and light chains, which upon ligation form an immunoglobulin M (IgM) B cell receptor (BCR) expressed on the surface of naïve immature B cells. Naïve B cells expressing either IgM or IgD isotypes are thought to play interchangeable functions in antibody responses to T cell-dependent and T cell-independent antigens. IgM short-lived plasma cells (SLPCs) and antigen-specific IgM memory B cells (MBCs-M) are critical in the first few days of infection, as well as long-term memory induced by vaccination, respectively. At mucosal surfaces, IgM is thought to play a critical part in promoting mucosal tolerance and shaping microbiota together with IgA. In this review, we explore how IgM structure and BCR signaling shapes B cell development, self and non-self-antigen-specific antibody responses, responses to infectious (such as viruses, parasites, and fungal) and non-communicable diseases (such as autoimmunity and allergic asthma). We also explore how metabolism could influence other B cell functions such as mucosal tolerance and class switching. Finally, we discuss some of the outstanding critical research questions in both experimental and clinical settings targeting IgM.

Mid-life microbiota crises: middle age is associated with pervasive neuroimmune alterations that are reversed by targeting the gut microbiome

Male middle age is a transitional period where many physiological and psychological changes occur leading to cognitive and behavioural alterations, and a deterioration of brain function. However, the mechanisms underpinning such changes are unclear. The gut microbiome has been implicated as a key mediator in the communication between the gut and the brain, and in the regulation of brain homeostasis, including brain immune cell function. Thus, we tested whether targeting the gut microbiome by prebiotic supplementation may alter microglia activation and brain function in ageing. Male young adult (8 weeks) and middle-aged (10 months) C57BL/6 mice received diet enriched with a prebiotic (10% oligofructose-enriched inulin) or control chow for 14 weeks. Prebiotic supplementation differentially altered the gut microbiota profile in young and middle-aged mice with changes correlating with faecal metabolites. Functionally, this translated into a reversal of stress-induced immune priming in middle-aged mice. In addition, a reduction in ageing-induced infiltration of Ly-6C^hi monocytes into the brain coupled with a reversal in ageing-related increases in a subset of activated microglia (Ly-6C⁺) was observed. Taken together, these data highlight a potential pathway by which targeting the gut microbiome with prebiotics can modulate the peripheral immune response and alter neuroinflammation in middle age. Our data highlight a novel strategy for the amelioration of age-related neuroinflammatory pathologies and brain function.

Gut microbiota of obese and diabetic Thai subjects and interplay with dietary habits and blood profiles

Obesity and type 2 diabetes mellitus (T2DM) have become major public health issues globally. Recent research indicates that intestinal microbiota play roles in metabolic disorders. Though there are numerous studies focusing on gut microbiota of health and obesity states, those are primarily focused on Western countries. Comparatively, only a few investigations exist on gut microbiota of people from Asian countries. In this study, the fecal microbiota of 30 adult volunteers living in Chiang Rai Province, Thailand were examined using next-generation sequencing (NGS) in association with blood profiles and dietary habits. Subjects were categorized by body mass index (BMI) and health status as follows; lean (L) = 8, overweight (OV) = 8, obese (OB) = 7 and diagnosed T2DM = 7. Members of T2DM group showed differences in dietary consumption and fasting glucose level compared to BMI groups. A low level of high-density cholesterol (HDL) was observed in the OB group. Principal coordinate analysis (PCoA) revealed that microbial communities of T2DM subjects were clearly distinct from those of OB. An analogous pattern was additionally illustrated by multiple factor analysis (MFA) based on dietary habits, blood profiles, and fecal gut microbiota in BMI and T2DM groups. In all four groups, Bacteroidetes and Firmicutes were the predominant phyla. Abundance of Faecalibacterium prausnitzii, a butyrate-producing bacterium, was significantly higher in OB than that in other groups. This study is the first to examine the gut microbiota of adult Thais in association with dietary intake and blood profiles and will provide the platform for future investigations.

Effects of exercise frequency on the gut microbiota in elderly individuals

Growing evidence has shown that exercise can affect the gut microbiota. The effects of exercise frequency on the gut microbiota in elderly individuals are still largely unknown. In the present study, samples from 897 elderly and 1,589 adult individuals (18–60 years old) from the American Gut Project were screened. Microbial diversity and composition were analyzed by QIIME2, and microbial function was predicted by PICRUSt2. The outcomes were further analyzed by STAMP. The analysis showed that the α‐diversity of gut microbiota increased with increasing age, and regular exercise reshaped the alterations in microbial composition and function induced by aging. Moreover, the α‐diversity of gut microbiota was higher in overweight elderly individuals than in normoweight elderly individuals, and regular exercise significantly affected the microbial composition and function in overweight elderly individuals. In conclusion, we revealed that regular exercise benefits elderly individuals, especially overweight elderly individuals, by modulating the gut microbiota.

Human Secretory IgM: An Elusive Player in Mucosal Immunity

Secretory IgMs (SIgMs) were amongst the first identified immunoglobulins. However, their importance was not fully understood and recent advances have shown they play a key role in establishing and promoting commensal gut tolerance in mice and humans. The true interactions between SIgMs and the microbiota remain controversial and we aim to consolidate current knowledge in this review. Through comprehensive examination of SIgMs and their corresponding B cell secretors in several different pathological immunological contexts, we review the presumed role of these molecules in gut tolerance, inflammatory bowel diseases, and lung immunity. As SIgMs harbor a mostly tolerogenic function, we posit that their inclusion in further immunological research is paramount.

Chronic periodontitis induces microbiota-gut-brain axis disorders and cognitive impairment in mice

Epidemiological studies suggest that chronic periodontitis (CP) is closely associated with the incidence and progression of cognitive impairment. The present study investigated the causal relationship between CP and cognitive decline and the underlying mechanism in mice. Long-term ligature around the left second maxillary molar tooth was used to induce CP in mice. Severe alveolar bone loss and inflammatory changes were observed in gingival tissues, accompanied by progressive cognitive deficits during a 12-month period. We also observed cerebral neuronal and synaptic injury and glial activation in this mouse model of CP. Furthermore, CP mice exhibited significant dysbiosis of the oral and gut microbiota, disruption of the intestinal barrier and blood-brain barrier, increases in the serum contents of proinflammatory cytokines and lipopolysaccharide (LPS), and increases in brain LPS levels, Toll-like receptor 4 (TLR4) expression, nuclear factor-κB (NF-κB) nuclear translocation and proinflammatory cytokine mRNA levels. These results indicate that CP may directly induce progressive cognitive decline and its mechanism is probably related to microbiota-gut-brain axis disorders, LPS/TLR4/NF-κB signaling activation and neuroinflammatory responses in mice. Therefore, the microbiota-gut-brain axis may provide the potential strategy for the prevention and treatment of CP-associated cognitive impairment.

Long-term intake of Lactobacillus paracasei KW3110 prevents age-related chronic inflammation and retinal cell loss in physiologically aged mice

Age-related chronic inflammation is a major risk factor for the incidence and prevalence of age-related diseases, including infectious and neurodegenerative diseases. We previously reported that a lactic acid bacteria, Lactobacillus paracasei KW3110, activated macrophages and suppressed inflammation in mice and humans. In this study, we investigated whether long-term intake of heat-killed L. paracasei KW3110 modulated age-related inflammation and altered the gut microbiota in physiologically aged mice. Compared with age-matched control mice, fecal analyses of gut microbiota revealed that intake of L. paracasei KW3110 mitigated age-related changes of beneficial bacterial composition, including the Bifidobacteriaceae family. L. paracasei KW3110 intake also mitigated age-related immune defects by reducing the prevalence of interferon-gamma (IFN-γ) -producing inflammatory CD4-positive T cells in the lamina propia of the small intestine, and reduced serum levels of proinflammatory cytokines. Furthermore, L. paracasei KW3110 intake suppressed retinal inflammation by reducing proinflammatory cytokine-producing macrophage, and age-related retinal cell loss. Taken together, these findings suggested that L. paracasei KW3110 mitigated age-related chronic inflammation through modulation of gut microbiota composition and immune system functions in aged mice, and also reduced age-related retinal ganglion cell (RGC) loss. Further studies are needed to evaluate the effect in age-related senescent changes of the retina.

The Microbiota-Gut-Brain Axis

The importance of the gut-brain axis in maintaining homeostasis has long been appreciated. However, the past 15 yr have seen the emergence of the microbiota (the trillions of microorganisms within and on our bodies) as one of the key regulators of gut-brain function and has led to the appreciation of the importance of a distinct microbiota-gut-brain axis. This axis is gaining ever more traction in fields investigating the biological and physiological basis of psychiatric, neurodevelopmental, age-related, and neurodegenerative disorders. The microbiota and the brain communicate with each other via various routes including the immune system, tryptophan metabolism, the vagus nerve and the enteric nervous system, involving microbial metabolites such as short-chain fatty acids, branched chain amino acids, and peptidoglycans. Many factors can influence microbiota composition in early life, including infection, mode of birth delivery, use of antibiotic medications, the nature of nutritional provision, environmental stressors, and host genetics. At the other extreme of life, microbial diversity diminishes with aging. Stress, in particular, can significantly impact the microbiota-gut-brain axis at all stages of life. Much recent work has implicated the gut microbiota in many conditions including autism, anxiety, obesity, schizophrenia, Parkinson’s disease, and Alzheimer’s disease. Animal models have been paramount in linking the regulation of fundamental neural processes, such as neurogenesis and myelination, to microbiome activation of microglia. Moreover, translational human studies are ongoing and will greatly enhance the field. Future studies will focus on understanding the mechanisms underlying the microbiota-gut-brain axis and attempt to elucidate microbial-based intervention and therapeutic strategies for neuropsychiatric disorders.

The Microbiome and Aging

Aging is a natural process of organismal decay that underpins the development of myriad diseases and disorders. Extensive efforts have been made to understand the biology of aging and its regulation, but most studies focus solely on the host organism. Considering the pivotal role of the microbiota in host health and metabolism, we propose viewing the host and its microbiota as a single biological entity whose aging phenotype is influenced by the complex interplay between host and bacterial genetics. In this review we present how the microbiota changes as the host ages, but also how the intricate relationship between host and indigenous bacteria impacts organismal aging and life span. In addition, we highlight other microbiota-dependent mechanisms that potentially regulate aging, and present experimental animal models for addressing these questions. Importantly, we propose microbiome dysbiosis as an additional hallmark and biomarker of aging.

Save your gut save your age: The role of the microbiome in stem cell ageing

The tremendous importance of microbiota in microbial homoeostasis, alterations in metabolism and both innate and adaptive immune systems has been well established. A growing body of evidence support that dysbiosis or compositional changes in gut microbiota is linked to the ageing of stem cells in terms of dysregulations of metabolism, aberrant activation of the immune system as well as promoting epigenetic instability of stem cell. In this concise review, we elucidate recent emerging topics on microbiotic alterations and underlying mechanisms in stem cell ageing.

Drinking Warm Water Improves Growth Performance and Optimizes the Gut Microbiota in Early Postweaning Rabbits during Winter

Accumulating evidence indicates that cold exposure changes the composition of the gut microbiota and reduces intestinal immunity in early postweaning livestock. However, little is known about the effects of drinking warm water (WW) on gut microbiota during winter. In this study, we investigated the effects of drinking WW in winter on the growth performance and gut microbiota structure of rabbits raised in poorly insulated housing from the early postweaning period (day 46) to the subadult period (day 82). The average daily gain and feed conversion ratio in rabbits drinking WW were significantly improved compared to those of the rabbits drinking cold water (CW) during 47-58 days. In addition, rabbits drinking WW had a significantly decreased the risk of diarrhea during 71-82 days. 16S rRNA sequence analysis revealed that the alpha diversity of the cecal microbiota was not significantly different between the WW and CW groups, but significantly increased with age. The relative abundance of cecal microorganisms, such as Coprococcus spp. was considerably increased at day 70 in the group drinking WW. Correlation analysis indicated that Coprococcus spp. was negatively associated with pro-inflammatory factors. In conclusion, our results suggest that drinking WW has a positive effect on growth performance and gut microbiota in rabbits during the early postweaning stage in winter.

The Gut-Immune-Brain Axis in Autism Spectrum Disorders; A Focus on Amino Acids

Autism spectrum disorder (ASD) is a range of neurodevelopmental conditions that affect communication and social behavior. Besides social deficits, systemic inflammation, gastrointestinal immune-related problems, and changes in the gut microbiota composition are characteristic for people with ASD. Animal models showed that these characteristics can induce ASD-associated behavior, suggesting an intimate relationship between the microbiota, gut, immune system and the brain in ASD. Multiple factors can contribute to the development of ASD, but mutations leading to enhanced activation of the mammalian target of rapamycin (mTOR) are reported frequently. Hyperactivation of mTOR leads to deficits in the communication between neurons in the brain and to immune impairments. Hence, mTOR might be a critical factor linking the gut-brain-immune axis in ASD. Pharmacological inhibition of mTOR is shown to improve ASD-associated behavior and immune functions, however, the clinical use is limited due to severe side reactions. Interestingly, studies have shown that mTOR activation can also be modified by nutritional stimuli, in particular by amino acids. Moreover, specific amino acids are demonstrated to inhibit inflammation, improve gut barrier function and to modify the microbiota composition. In this review we will discuss the gut-brain-immune axis in ASD and explore the potential of amino acids as a treatment option for ASD, either via modification of mTOR activity, the immune system or the gut microbiota composition.

The intestinal microbiome and its relevance for functionality in older persons

PURPOSE OF REVIEW

This article summarizes the advances of research on the role of the intestinal microbiota in influencing sarcopenia, frailty, and cognitive dysfunction in older individuals, and thus its relevance for healthy active ageing.

RECENT FINDINGS

Age-related alterations of intestinal microbiota composition may negatively influence muscle protein synthesis and function by promoting chronic systemic inflammation, insulin resistance, oxidative stress, and reducing nutrient bioavailability. However, this 'gut-muscle axis' hypothesis is not supported by human data to date. Some observational studies have instead demonstrated that, in older individuals, frailty and Alzheimer-type dementia are associated with fecal microbiota dysbiosis, that is, reduced biodiversity and overexpression of pathobionts. The main possible mechanisms of the 'gut-brain axis' in cognitive function modulation include effects on neurotransmission, neuroinflammation, and amyloid deposition. Conversely, longevity in good health may be associated with the maintenance of a fecal microbiota composition similar to that of healthy young adults. However, the role of gut microbiota as an independent modulator of frailty and cognition still remains uncertain, being influenced by several physiological factors, including diet and exercise.

SUMMARY

The intestinal microbiome composition represents a possible determinant of functional performance in older people, and a promising target for antiaging therapeutic interventions.

The impact of Helicobacter pylori infection, eradication therapy and probiotic supplementation on gut microenvironment homeostasis: An open-label, randomized clinical trial

Background

Helicobacter pylori (H. pylori) infection is associated with remodeling of gastric microbiota. However, comprehensive analyses of the impact of H. pylori infection, eradication therapy and probiotic supplementation on gut microbiota are still lacking. We aimed to provide evidence for clinical decision making.

Methods

Seventy H. pylori-positive and 35 H. pylori-negative patients (group C) were enrolled. H. pylori-positive patients were randomly assigned to group A (14-day bismuth-containing quadruple therapy) and group B (quadruple therapy supplemented with Clostridium butyricum). Stool samples of group A and B were collected on day 0, 14 and 56 while stool samples of group C were collected on day 0. Gut microbiota was investigated by 16S rRNA sequencing.

Findings

The Sobs index (richness estimator) was significantly higher in H. pylori-positive samples than H. pylori-negative samples (p < .05). Several metabolic pathways were more abundant in H. pylori-positive communities while some disease-associated pathways had higher potential in H. pylori-negative community through KEGG pathway analysis. Abundances of most butyrate-producing bacteria significantly decreased, while several detrimental bacteria increased after eradication therapy. Probiotic supplementation was associated with improved gastrointestinal symptoms as well as increased Bacteroidetes:Firmicutes ratio.

Interpretation

While H. pylori infection may not be necessarily detrimental in all patients, eradication of H. pylori was associated with widespread changes in gut microbial ecology and structure. Probiotic supplementation could relieve more gastrointestinal symptoms by inducing alterations in gut microbiota and host immune responses. As such, the decision to eradicate H. pylori should be based on comprehensive analysis of individual patients.