Gut microbiota: A player in aging and a target for anti-aging intervention

Age-related sarcopenia and altered gut microbiota: A systematic review

BACKGROUND

Sarcopenia, a hallmark of age-related muscle function decline, significantly impacts elderly physical health. This systematic review aimed to investigate the impact of gut microbiota on sarcopenia.

METHODS

Publications up to September 24, 2023 were scrutinized on four databases - PubMed, Web of Science, Cochrane Library, and Embase - using relevant keywords. Non-English papers were disregarded. Data regarding gut microbiota alterations in sarcopenic patients/animal models were collected and examined.

RESULTS

Thirteen human and eight animal studies were included. The human studies involved 732 sarcopenic or potentially sarcopenic participants (aged 57-98) and 2559 healthy subjects (aged 54-84). Animal studies encompassed five mouse and three rat experiments. Results indicated an increase in opportunistic pathogens like Enterobacteriaceae, accompanied by changes in several metabolite-related organisms. For example, Bacteroides fluxus related to horse uric acid metabolism exhibited increased abundance. However, Roseburia, Faecalibacterium, Faecalibacterium prausnitzii, Eubacterium retale, Akkermansiaa, Coprococcus, Clostridium_XIVa, Ruminococcaceae, Bacteroides, Clostridium, Eubacterium involved in urolithin A production, and Lactobacillus, Bacteroides, and Clostridium associated with bile acid metabolism displayed decreased abundance.

CONCLUSIONS

Age-related sarcopenia and gut microbiota alterations are intricately linked. Short-chain fatty acid metabolism, urolithin A, and bile acid production may be pivotal factors in the gut-muscle axis pathway. Supplementation with beneficial metabolite-associated microorganisms could enhance muscle function, mitigate muscle atrophy, and decelerate sarcopenia progression.

The connection between aging, cellular senescence and gut microbiome alterations: A comprehensive review

The intricate interplay between cellular senescence and alterations in the gut microbiome emerges as a pivotal axis in the aging process, increasingly recognized for its contribution to systemic inflammation, physiological decline, and predisposition to age-associated diseases. Cellular senescence, characterized by a cessation of cell division in response to various stressors, induces morphological and functional changes within tissues. The complexity and heterogeneity of senescent cells, alongside the secretion of senescence-associated secretory phenotype, exacerbate the aging process through pro-inflammatory pathways and influence the microenvironment and immune system. Concurrently, aging-associated changes in gut microbiome diversity and composition contribute to dysbiosis, further exacerbating systemic inflammation and undermining the integrity of various bodily functions. This review encapsulates the burgeoning research on the reciprocal relationship between cellular senescence and gut dysbiosis, highlighting their collective impact on age-related musculoskeletal diseases, including osteoporosis, sarcopenia, and osteoarthritis. It also explores the potential of modulating the gut microbiome and targeting cellular senescence as innovative strategies for healthy aging and mitigating the progression of aging-related conditions. By exploring targeted interventions, including the development of senotherapeutic drugs and probiotic therapies, this review aims to shed light on novel therapeutic avenues. These strategies leverage the connection between cellular senescence and gut microbiome alterations to advance aging research and development of interventions aimed at extending health span and improving the quality of life in the older population.

Microglia and gut microbiota: A double-edged sword in Alzheimer's disease

The strong association between gut microbiota (GM) and brain functions such as mood, behaviour, and cognition has been well documented. Gut-brain axis is a unique bidirectional communication system between the gut and brain, in which gut microbes play essential role in maintaining various molecular and cellular processes. GM interacts with the brain through various pathways and processes including, metabolites, vagus nerve, HPA axis, endocrine system, and immune system to maintain brain homeostasis. GM dysbiosis, or an imbalance in GM, is associated with several neurological disorders, including anxiety, depression, and Alzheimer's disease (AD). Conversely, AD is sustained by microglia-mediated neuroinflammation and neurodegeneration. Further, GM and their products also affect microglia-mediated neuroinflammation and neurodegeneration. Despite the evidence connecting GM dysbiosis and AD progression, the involvement of GM in modulating microglia-mediated neuroinflammation in AD remains elusive. Importantly, deciphering the mechanism/s by which GM regulates microglia-dependent neuroinflammation may be helpful in devising potential therapeutic strategies to mitigate AD. Herein, we review the current evidence regarding the involvement of GM dysbiosis in microglia activation and neuroinflammation in AD. We also discuss the possible mechanisms through which GM influences the functioning of microglia and its implications for therapeutic intervention. Further, we explore the potential of microbiota-targeted interventions, such as prebiotics, probiotics, faecal microbiota transplantation, etc., as a novel therapeutic strategy to mitigate neuroinflammation and AD progression. By understanding and exploring the gut-brain axis, we aspire to revolutionize the treatment of neurodegenerative disorders, many of which share a common theme of microglia-mediated neuroinflammation and neurodegeneration.

Microbiome as an endocrine organ and its relationship with eye diseases: Effective factors and new targeted approaches

Microbiome is an endocrine organ that refers to both the complicated biological system of microbial species that colonize our bodies and their genomes and surroundings. Recent studies confirm the connection between the microbiome and eye diseases, which are involved in the pathogenesis of eye diseases, including age-related macular disorders, diabetic retinopathy, glaucoma, retinitis pigmentosa, dry eye, and uveitis. The aim of this review is to investigate the microbiome in relation to eye health. First, a brief introduction of the characteristics of the gut microorganisms terms of composition and work, the role of dysbiosis, the gut microbiome and the eye microbiome in the progression of eye illnesses are highlighted, then the relationship among the microbiome and the function of the immune system and eye diseases, the role of inflammation and aging and the immune system, It has been reviewed and finally, the control and treatment goals of microbiome and eye diseases, the role of food factors and supplements, biotherapy and antibiotics in relation to microbiome and eye health have been reviewed.

Research on the mechanism of buyang huanwu decoction in the amelioration of age-associated memory impairment based on the "co-occurrence network regulation of intestinal microecology-host metabolism-immune function"

ETHNOPHARMACOLOGICAL RELEVANCE

Brain aging can promote neuronal damage, contributing to aging-related diseases like memory dysfunction. Buyang Huanwu Decoction (BYHWD), a traditional Chinese medicine formula known for tonifying qi and activating blood circulation, shows neuroprotective properties. Despite this, the specific mechanism by which BYHWD improves age-associated memory impairment (AAMI) has not been explored in existing literature.

AIM OF THE STUDY

This study aimed to investigate the mechanism of BYHWD in the improvement of AAMI based on the "co-occurrence network regulation of intestinal microecology-host metabolism-immune function".

MATERIALS AND METHODS

Firstly, D-galactose was performed to induce a rat model of AAMI. Learning and memory deficits was assessed by the Morris water maze test. H&E and Nissl staining were used to observe the pathological changes in neurons in the hippocampus of rats. Meanwhile, the levels of pro-inflammatory cytokines and the activation of antioxidant enzymes in rat serum were measured using ELISA. Finally, an integrated pharmacological approach was applied to explore the potential mechanism of BYHWD in improving AAMI.

RESULTS

Our results indicated that BYHWD significantly mitigated the pathological structure of the hippocampus, reversed the levels of IL-6, TNF-α, GSH, and CAT in the serum, and improved learning and memory in aging rats. Transcriptomics combined with network pharmacology showed that energy metabolism and the inflammatory response were the key biological pathways for BYHWD to ameliorate AAMI. Integrative analysis of the microbiome and metabolomics revealed that BYHWD has the potential to restore the balance of abundance between probiotics and harmful bacteria, and ameliorate the reprogramming of energy metabolism caused by aging in the brain. The co-occurrence network analysis demonstrated that a strong correlation between the treatment of AAMI and the stability of intestinal microecology, host metabolism, and immune network.

CONCLUSION

The findings of this study collectively support the notion that BYHWD has a superior therapeutic effect in an AAMI rat model. The mechanism involves regulating the "intestinal microecology-metabolism-immune function co-occurrence network" system to restore the composition of gut microbiota and metabolites. This further improves the metabolic phenotype of brain tissue and maintains the homeostasis of central nervous system's immunity, leading to an improvement in AAMI. Consequently, this study offers a unique perspective on the prevention and treatment of AAMI. And, BYHWD is also considered to be a promising preclinical treatment for improving AAMI.

Impact of gut microbiota on cardiac aging

Recent research has suggested imbalances in gut microbiota composition as contributors to cardiac aging. An individual's physical condition, along with lifestyle-associated factors, including diet and medication, are significant determinants of gut microbiota composition. This review discusses evidence of bidirectional associations between aging and gut microbiota, identifying gut microbiota-derived metabolites as potential regulators of cardiac aging. It summarizes the effects of gut microbiota on cardiac aging diseases, including cardiac hypertrophy and fibrosis, heart failure, and atrial fibrillation. Furthermore, this review discusses the potential anti-aging effects of modifying gut microbiota composition through dietary and pharmacological interventions. Lastly, it underscores critical knowledge gaps and outlines future research directions. Given the current limited understanding of the direct relationship between gut microbiota and cardiac aging, there is an urgent need for preclinical and clinical investigations into the mechanistic interactions between gut microbiota and cardiac aging. Such endeavors hold promise for shedding light on the pathophysiology of cardiac aging and uncovering new therapeutic targets for cardiac aging diseases.

Saccharomyces boulardii improves clinical and paraclinical indices in overweight/obese knee osteoarthritis patients: a randomized triple-blind placebo-controlled trial

PURPOSE

This study aimed to determine the effect of the probiotic Saccharomyces boulardii (S. boulardii) in patients with knee osteoarthritis (KOA).

METHODS

In this study, 70 patients with KOA were recruited via outpatient clinics between 2020 and 2021 and randomly assigned to receive probiotics or placebo supplements for 12 weeks. The primary outcome was a change in pain intensity according to the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score.

RESULTS

Sixty-three patients completed the trial. A linear mixed analysis of covariance (ANCOVA) model analysis showed that probiotic was better than placebo in decreasing the pain intensity measured by visual analogue scale (VAS) [-2.11 (-2.59, -1.62) in probiotic group and -0.90 (-1.32, -0.48) in placebo group, p = 0.002] and WOMAC pain score [-3.57 (-4.66, -2.49) in probiotic group and -1.43 (-2.33, -0.53) in placebo group, p < 0.001]. The daily intake of acetaminophen for pain management significantly decreased in the probiotic group [-267.18 (-400.47, -133.89) mg, p < 0.001] that was significantly better than placebo (p = 0.006). Probiotic significantly decreased the serum levels of high-sensitivity C-reactive protein (hs-CRP) inflammatory index [-2.72 (-3.24, -2.20) µg/ml] and malondialdehyde (MDA) oxidative stress index [-1.61 (-2.11, -1.11) nmol/ml] compared to the placebo (p = 0.002 and p < 0.001, respectively). Probiotic was better than placebo in increasing the scores of role disorder due to physical health (p = 0.023), pain (p = 0.048) and physical health (p = 0.031).

CONCLUSION

Probiotic S. boulardii supplementation in patients with KOA significantly improved pain intensity, some dimensions of QoL, and inflammatory and oxidative stress biomarkers with no severe side effects.

TRIAL REGISTRY

Registered on the Iranian clinical trial website ( http://www.irct.ir : IRCT20161022030424N4) on 2019-09-02.

Cereal polyphenols inhibition mechanisms on advanced glycation end products and regulation on type 2 diabetes

Advanced glycation end products (AGEs), the products of non-enzymatic browning reactions between the active carbonyl groups of reducing sugars and the free amines of amino acids, are largely considered oxidative derivatives resulting from diabetic hyperglycemia, which are further recognized as a potential risk for insulin resistance (IR) and type 2 diabetes (T2D). The accumulation of AGEs can trigger numerous negative effects such as oxidative stress, carbonyl stress, inflammation, autophagy dysfunction and imbalance of gut microbiota. Recently, studies have shown that cereal polyphenols have the ability to inhibit the formation of AGEs, thereby preventing and alleviating T2D. In the meanwhile, phenolics compounds could produce different biological effects due to the quantitative structure activity-relationship. This review highlights the effects of cereal polyphenols as a nonpharmacologic intervention in anti-AGEs and alleviating T2D based on the effects of oxidative stress, carbonyl stress, inflammation, autophagy, and gut microbiota, which also provides a new perspective on the etiology and treatment of diabetes.

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.

Gut microbiota changes in patients with Alzheimer's disease spectrum based on 16S rRNA sequencing: a systematic review and meta-analysis

Background

The gut microbiota (GM) is hypothesized to play roles in Alzheimer's disease (AD) pathogenesis. In recent years, many GM composition and abundance investigations in AD patients have been conducted; however, despite this work, some results remain controversial. Therefore, we conducted a systematic review and meta-analysis using 16S ribosomal RNA (16S rRNA) sequencing to explore GM alterations between patients with AD spectrum and healthy controls (HCs).

Methods

A systematic and comprehensive literature search of PubMed, Web of Science, Embase, the Cochrane Library, China National Knowledge Infrastructure, China Biology Medicine disc database, WanFang database and Social Sciences Citation Index databases was conducted from inception to January 2023. Inclusion and exclusion criteria were strictly defined, and two researchers independently screened and extracted information from selected studies. Data quality were evaluated according to the "Cochrane system evaluator manual" and pooled data were comprehensively analyzed using Stata 14 software with standardized mean differences (SMDs) and 95% confidence intervals (95% CIs) used to measure effect sizes. Also, geographical heterogeneity effects (related to cohorts) on GM abundance were examined based on subgroup meta-analyses if sufficient studies reported outcomes. Finally, publication bias was assessed using funnel plots.

Results

Out of 1566 articles, 13 studies involving 581 patients with AD spectrum and 445 HCs were deemed eligible and included in our analysis. In summary, a decreased microbiota alpha diversity and a significantly distinct pattern of clustering with regard to beta diversity were observed in AD spectrum patients when compared with HCs. Comparative analyses revealed a decreased Ruminococcus, Faecalibacterium, Lachnospira, Dialister, Lachnoclostridium, and Roseburia abundance in AD spectrum patients while Phascolarctobacterium, Lactobacillus, and Akkermansia muciniphila were more enriched in patients when compared to HCs. Furthermore, regional variations may have been in play for intestinal microbes such as Bacteroides, Bifidobacterium, and Alistipes.

Conclusion

Our meta-analysis identified alterations in GM abundance in patients with AD spectrum, with 12 genera from four major phyla significantly associated with AD. Moreover, we provided evidence for region-specific alterations in Bacteroides, Bifidobacterium, and Alistipes abundance. These findings may have profound implications for the development of innovative GM-based strategies to prevent and treat AD.

Systematic review registration

https://doi.org/10.37766/inplasy2024.6.0067, identifier INPLASY202460067.

Harnessing immunomodulation to combat sarcopenia: current insights and possible approaches

Sarcopenia is a complex age-associated syndrome of progressive loss of muscle mass and strength. Although this condition is influenced by many factors, age-related changes in immune function including immune cell dynamics, and chronic inflammation contribute to its progression. The complex interplay between the immune system, gut-muscle axis, and autophagy further underscores their important roles in sarcopenia pathogenesis. Immunomodulation has emerged as a promising strategy to counteract sarcopenia. Traditional management approaches to treat sarcopenia including physical exercise and nutritional supplementation, and the emerging technologies of biophysical stimulation demonstrated the importance of immunomodulation and regulation of macrophages and T cells and reduction of chronic inflammation. Treatments to alleviate low-grade inflammation in older adults by modulating gut microbial composition and diversity further combat sarcopenia. Furthermore, some pharmacological interventions, nano-medicine, and cell therapies targeting muscle, gut microbiota, or autophagy present additional avenues for immunomodulation in sarcopenia. This narrative review explores the immunological underpinnings of sarcopenia, elucidating the relationship between the immune system and muscle during ageing. Additionally, the review discusses new areas such as the gut-muscle axis and autophagy, which bridge immune system function and muscle health. Insights into current and potential approaches for sarcopenia management through modulation of the immune system are provided, along with suggestions for future research directions and therapeutic strategies. We aim to guide further investigation into clinical immunological biomarkers and identify indicators for sarcopenia diagnosis and potential treatment targets to combat this condition. We also aim to draw attention to the importance of considering immunomodulation in the clinical management of sarcopenia.

Immune Remodeling during Aging and the Clinical Significance of Immunonutrition in Healthy Aging

Aging is associated with changes in the immune system and the gut microbiota. Immunosenescence may lead to a low-grade, sterile chronic inflammation in a multifactorial and dynamic way, which plays a critical role in most age-related diseases. Age-related changes in the gut microbiota also shape the immune and inflammatory responses. Nutrition is a determinant of immune function and of the gut microbiota. Immunonutrion has been regarded as a new strategy for disease prevention and management, including many age-related diseases. However, the understanding of the cause-effect relationship is required to be more certain about the role of immunonutrition in supporting the immune homeostasis and its clinical relevance in elderly individuals. Herein, we review the remarkable quantitative and qualitative changes during aging that contribute to immunosenescence, inflammaging and microbial dysbiosis, and the effects on late-life health conditions. Furthermore, we discuss the clinical significance of immunonutrition in the treatment of age-related diseases by systematically reviewing its modulation of the immune system and the gut microbiota to clarify the effect of immunonutrition-based interventions on the healthy aging.

Apple polysaccharide improves age-matched cognitive impairment and intestinal aging through microbiota-gut-brain axis

The Apple polysaccharides (AP), extracted from the fruit of apple, has been used to treat multiple pathological diseases. In this study, we evaluated the effects of AP on cognitive impairment and intestinal aging in naturally aging mice. As a result, it was found that AP could improve spatial learning and memory impairment in aging mice through the Morris water maze experiment. Additionally, AP intervention can upregulate the expression of nerve growth factor (BDNF), postsynaptic marker (PSD95), and presynaptic marker (SYP) proteins. Moreover, AP can enhance total antioxidant capacity, reduce the level of pro-inflammatory cytokine, and inhibit the activation of the NF-κB signaling pathway, exerting anti-inflammatory and antioxidant functions. And the administration of AP restored intestinal mucosal barrier function, reduced the expression of aging and apoptosis related proteins. The administration of AP also altered the gut microbiota of mice. At the genus level, AP decreased the abundance of Helicobacter and Bilophila, while increased the abundance of Lactobacillus and Bacteroides. In summary, these data demonstrate that AP treatment can alleviate cognitive impairment, oxidative stress, and inflammatory reactions, repair the intestinal mucosal barrier, reduce intestinal aging, and alter specific microbial characteristics, ultimately improving the health of the elderly.

Phytonutrients in the promotion of healthspan: a new perspective

Considering a growing, aging population, the need for interventions to improve the healthspan in aging are tantamount. Diet and nutrition are important determinants of the aging trajectory. Plant-based diets that provide bioactive phytonutrients may contribute to offsetting hallmarks of aging and reducing the risk of chronic disease. Researchers now advocate moving toward a positive model of aging which focuses on the preservation of functional abilities, rather than an emphasis on the absence of disease. This narrative review discusses the modulatory effect of nutrition on aging, with an emphasis on promising phytonutrients, and their potential to influence cellular, organ and functional parameters in aging. The literature is discussed against the backdrop of a recent conceptual framework which describes vitality, intrinsic capacity and expressed capacities in aging. This aims to better elucidate the role of phytonutrients on vitality and intrinsic capacity in aging adults. Such a review contributes to this new scientific perspective-namely-how nutrition might help to preserve functional abilities in aging, rather than purely offsetting the risk of chronic disease.

Quorum sensing effect of chiral d-glutamine on the modulation of the intestinal microbiota of mice by Lactiplantibacillus plantarum A3

BACKGROUND

Amino acids (AAs) are the building blocks of proteins, but they also serve as biological compounds in biochemical processes, and d-AA isomers are increasingly being recognized as important signaling molecules. As the main organic substrate used by cells in the intestinal tract, the role of the chiral specificity of glutamine is still largely ignored.

RESULTS

In a previous study, we found that d-glutamine affected the quorum sensing of Lactiplantibacillus plantarum A3, promoted the release of signaling molecule AI-2 and up-regulated the expression of the LuxS gene. The results showed that when d-glutamine and L. plantarum A3 were simultaneously applied to a mouse model, the diversity and abundance of intestinal flora in both male and female mice were increased. Interestingly, the simultaneous effect of d-glutamine and L. plantarum A3 on the bacterial diversity and abundance of male mice was significantly higher than that of female mice. In addition, the combination of d-glutamine and L. plantarum A3 can improve the host microecology by enhancing the population of Firmicutes such as Lactobacillus and Lachnospiraceae, reducing the population of Fusobacterium and Bacteroides and affecting metabolic pathways such as AA metabolism and transporter transport.

CONCLUSION

d-Glutamine, as a signaling molecule, can better stimulate the endogenous d-glutamine synthesis in mice and be utilized by L. plantarum A3. Furthermore, sex differences in the changes of intestinal microflora are also found in this research. This research sheds some light on the adoption of d-AAs combined with lactic acid bacteria in intestinal tract health treatment. © 2024 Society of Chemical Industry.

Age over sex: evaluating gut microbiota differences in healthy Chinese populations

Age and gender have been recognized as two pivotal covariates affecting the composition of the gut microbiota. However, their mediated variations in microbiota seem to be inconsistent across different countries and races. In this study, 613 individuals, whom we referred to as the "healthy" population, were selected from 1,018 volunteers through rigorous selection using 16S rRNA sequencing. Three enterotypes were identified, namely, Escherichia-Shigella, mixture (Bacteroides and Faecalibacterium), and Prevotella. Moreover, 11 covariates that explain the differences in microbiota were determined, with age being the predominant factor. Furthermore, age-related differences in alpha diversity, beta diversity, and core genera were observed in our cohort. Remarkably, after adjusting for 10 covariates other than age, abundant genera that differed between age groups were demonstrated. In contrast, minimal differences in alpha diversity, beta diversity, and differentially abundant genera were observed between male and female individuals. Furthermore, we also demonstrated the age trajectories of several well-known beneficial genera, lipopolysaccharide (LPS)-producing genera, and short-chain fatty acids (SCFAs)-producing genera. Overall, our study further elucidated the effects mediated by age and gender on microbiota differences, which are of significant importance for a comprehensive understanding of the gut microbiome spectrum in healthy individuals.

Association between oxidative balance score and serum uric acid and hyperuricemia: a population-based study from the NHANES (2011-2018)

Background

Oxidative Balance Score (OBS) is a novel indicator of the overall antioxidant/oxidant balance, providing a comprehensive reflection of the body's overall oxidative stress status, with higher OBS suggesting more substantial antioxidant exposures. We aimed to investigate the possible relationship between OBS with serum uric acid (SUA) and hyperuricemia.

Methods

Data utilized in this study were sourced from the 2011-2018 National Health and Nutrition Examination Survey (NHANES). Participants under 18 years old, those with ≤16 complete data out of 20 OBS components, incomplete serum uric acid data, and missing covariates were excluded from the analysis. OBS was computed by evaluating 16 nutrients and 4 lifestyle factors, encompassing 5 pro-oxidants and 15 antioxidants, guided by a priori knowledge of their relationship with oxidative stress.

Results

A total of 1,5096 individuals were included in our analysis with 49.7% being male, and an average age of 49.05 ± 17.56 years. The mean OBS was 19.76 ± 7.17. Hyperuricemia was present in 19.28% of participants. Due to the right-skewed distribution of the OBS, a natural log transformation was applied to address this issue, and Quartiles of lnOBS 1, 2, 3, and 4 were 1.10-2.56 (N=3526), 2.64-2.94 (N=3748), 3.00-3.22 (N=4026), and 3.26-3.61 (N=3796), respectively. Multivariable logistic regression showed that higher lnOBS quantiles were correlated with lower serum uric acid levels. Compared with the lowest lnOBS quantile, participants in the highest lnOBS quantile had a significant serum uric acid decrease of 16.94 μmol/L for each unit increase in lnOBS (β=-16.94, 95% CI: -20.44, -13.45). Similar negative associations were observed in the second-highest (β=-8.07, 95% CI: -11.45, -4.69) and third-highest (β=-11.69, 95% CI: -15.05, -8.34) lnOBS quantiles. The adjusted odds ratios (ORs) for hyperuricemia in Quartiles 1, 2, 3, and 4 were 1.00, 0.84 (95% CI: 0.75, 0.95), 0.78 (95% CI: 0.69, 0.88), and 0.62 (95% CI: 0.55, 0.71), respectively. Compared to Quartile 1, participants in Quartile 4 had a 38% lower prevalence of hyperuricemia. Subgroup analysis and interaction test showed that there was a significant dependence of sex between OBS and serum uric acid (p for interaction <0.05), but not hyperuricemia (p for interaction >0.05). Subgroup analysis stratified by age, BMI, hypertension, diabetes, and hyperlipidemia showed there is no significant dependence on these negative correlations (all p for interaction >0.05).

Conclusions

The serum uric acid levels and prevalence of hyperuricemia in US adults exhibited a negative association with OBS. By exploring this connection, our research aims to gain a better understanding of how oxidative balance affects the prevalence of hyperuricemia. This could provide valuable insights for developing preventive strategies and interventions for hyperuricemia. Additional large-scale prospective studies are required to explore the role of OBS in hyperuricemia further.

Genetic association of the gut microbiota with epigenetic clocks mediated by inflammatory cytokines: a Mendelian randomization analysis

Background

A new aging biomarker epigenetic clock has been developed. There exists a close link between aging and gut microbiota, which may be mediated by inflammatory cytokines. However, the relationship between the epigenetic clock, gut microbiota, and the mediating substances is unclear.

Methods

Two large genome-wide association meta-analyses were analyzed by two-sample Mendelian randomization. The results between gut microbiota and epigenetic clock were investigated using the four methods (Inverse variance weighted, MR-Egger, weighted median, MR-PRESSO). Genetic correlation was measured by Linked disequilibrium score regression (LDSC). The correctness of the study direction was checked by the Steiger test. Cochran's Q statistic and MR-Egger intercept were used as sensitivity analyses of the study. The two-step method was used to examine the mediating role of inflammatory cytokines. We use the Benjamini-Hochberg correction method to correct the P value.

Results

After FDR correction, multiple bacterial genera were significantly or suggestively associated with four epigenetic clocks (GrimAge, HannumAge, IEAA, PhenoAge). And we detected several inflammatory factors acting as mediators of gut microbiota and epigenetic clocks.

Conclusion

This study provides genetic evidence for a positive and negative link between gut microbiota and aging risk. We hope that by elucidating the genetic relationship and potential mechanisms between aging and gut microbiota, we will provide new avenues for continuing aging-related research and treatment.

How Diet and Lifestyle Can Fine-Tune Gut Microbiomes for Healthy Aging

Many physical, social, and psychological changes occur during aging that raise the risk of developing chronic diseases, frailty, and dependency. These changes adversely affect the gut microbiota, a phenomenon known as microbe-aging. Those microbiota alterations are, in turn, associated with the development of age-related diseases. The gut microbiota is highly responsive to lifestyle and dietary changes, displaying a flexibility that also provides anactionable tool by which healthy aging can be promoted. This review covers, firstly, the main lifestyle and socioeconomic factors that modify the gut microbiota composition and function during healthy or unhealthy aging and, secondly, the advances being made in defining and promoting healthy aging, including microbiome-informed artificial intelligence tools, personalized dietary patterns, and food probiotic systems.

The Therapeutic Potential of Hemp Seed Oil in D-Galactose-Induced Aging Rat Model Was Determined through the Combined Assessment of 1H NMR Metabolomics and 16S rRNA Gene Sequencing

Aging is an irreversible process of natural degradation of bodily function. The increase in the aging population, as well as the rise in the incidence of aging-related diseases, poses one of the most pressing global challenges. Hemp seed oil, extracted from the seeds of hemp (Cannabis sativa L.), possesses significant nutritional and biological properties attributed to its unique composition of polyunsaturated fatty acids and various antioxidant compounds. However, there is limited knowledge regarding the anti-aging mechanism of hemp seed oil. This study aimed to evaluate the beneficial effects and potential mechanisms of hemp seed oil in a D-galactose (D-gal)-induced aging rat model through a combined analysis of metabolomics and 16S rRNA gene sequencing. Using nuclear magnetic resonance (NMR)-based metabolomics, significant alterations in serum and urine metabolic phenotypes were observed between the D-gal-induced aging rat model and the healthy control group. Eight and thirteen differentially expressed metabolites related to aging were identified in serum and urine, respectively. Treatment with hemp seed oil significantly restored four and ten potential biomarkers in serum and urine, respectively. The proposed pathways primarily included energy metabolism, amino acid metabolism, one-carbon metabolism, and lipid metabolism. Furthermore, 16S rRNA gene sequencing analysis revealed significant changes in the gut microbiota of aged rats. Compared to the model group, the hemp seed oil group exhibited significant alterations in the abundance of 21 bacterial taxa at the genus level. The results indicated that hemp seed oil suppressed the prevalence of pathogenic bacterial genera such as Streptococcus, Rothia, and Parabacteroides. Additionally, it facilitated the proliferation of the genera Lachnospirace_NK4B4_group and Lachnospirace_UCG_001, while also enhancing the relative abundance of the genus Butyricoccus; a producer of short-chain fatty acids (SCFAs). These findings provided new insights into the pathogenesis of aging and further supported the potential utility of hemp seed oil as an anti-aging therapeutic agent.

Modulation of cyclophosphamide-induced immunosuppression and intestinal flora in broiler by deep eutectic solvent extracted polysaccharides of Acanthopanax senticosus

Introduction

The aim of this experiment was to investigate the modulation effect of Acanthopanax senticosus polysaccharide (ASPS-PD) extracted with deep eutectic solvent on cyclophosphamide-induced immunosuppression in broilers and its modulation of the gut microbiota of broilers.

Methods

The 108 one-day-old broilers were divided into six groups, including the control group, the Cyclophosphamide (CY) model group, the ASPS-PD control group, the ASPA-PD high and low dose groups and the Astragalus polysaccharide group. Body weight, feed intake, feed conversion ratio, and immune organ index of broilers at 7, 14, and 21 days were determined; IL-2, IFN-γ, and lgG1 levels were determined by enzyme-linked immunosorbent assay (ELISA); Broiler caeca feces were analyzed by amplification and 16S rRNA sequencing.

Results

The results showed that ASPS-PD can restore growth performance, increase immune organ index and improve serum cytokine levels of IL-2 and IFN-γ and immunoglobulin lgG1 levels in CY-treated broilers. The analysis of cecum flora showed that ASPS-PD can promote the proliferation of beneficial bacteria and reduce the number of harmful bacteria, regulating intestinal flora.

Discussion

Therefore, ASPA-PD may be a potential novel immunomodulator to ameliorate CY-induced immunosuppression and intestinal flora dysregulation in broiler.

Dietary supplementation with Lacticaseibacillus rhamnosus IDCC3201 alleviates sarcopenia by modulating the gut microbiota and metabolites in dexamethasone-induced models

Probiotics can exert direct or indirect influences on various aspects of health claims by altering the composition of the gut microbiome and producing bioactive metabolites. The aim of this study was to examine the effect of Lacticaseibacillus rhamnosus IDCC3201 on skeletal muscle atrophy in dexamethasone-induced C2C12 cells and a mouse animal model. Dexamethasone treatment significantly reduced C2C12 muscle cell viability, myotube diameter, and levels of muscle atrophic markers (Atrogin-1 and MuRF-1). These effects were alleviated by conditioned media (CM) and cell extract (EX) derived from L. rhamnosus IDCC3201. In addition, we assessed the in vivo therapeutic effect of L. rhamnosus IDCC3201 in a mouse model of dexamethasone (DEX)-induced muscle atrophy. Supplementation with IDCC3201 resulted in significant enhancements in body composition, particularly in lean mass, muscle strength, and myofibril size, in DEX-induced muscle atrophy mice. In comparison to the DEX-treatment group, the normal and DEX + L. rhamnosus IDCC3201 groups showed a higher transcriptional level of myosin heavy chain family genes (MHC1, MHC1b, MHC2A, 2bB, and 2X) and a reduction in atrophic muscle makers. These analyses revealed that L. rhamnosus IDCC3201 supplementation led to increased production of branched-chain amino acids (BCAAs) and improved the Allobaculum genus within the gut microbiota of muscle atrophy-induced groups. Taken together, our findings suggest that L. rhamnosus IDCC3201 represents a promising dietary supplement with the potential to alleviate sarcopenia by modulating the gut microbiome and metabolites.

The Benefits of the Mediterranean Diet on Inflamm-Aging in Childhood Obesity

(1) Background: Numerous elements of the Mediterranean diet (MD) have antioxidant and anti-inflammatory qualities. (2) Methods: We present a narrative review of the potential benefits of the Mediterranean dietary pattern (MD) in mitigating aging-related inflammation (inflamm-aging) associated with childhood obesity. The mechanisms underlying chronic inflammation in obesity are also discussed. A total of 130 papers were included after screening abstracts and full texts. (3) Results: A complex interplay between obesity, chronic inflammation, and related comorbidities is documented. The MD emerges as a promising dietary pattern for mitigating inflammation. Studies suggest that the MD may contribute to weight control, improved lipid profiles, insulin sensitivity, and endothelial function, thereby reducing the risk of metabolic syndrome in children and adolescents with obesity. (4) Conclusions: While evidence supporting the anti-inflammatory effects of the MD in pediatric obesity is still evolving, the existing literature underscores its potential as a preventive and therapeutic strategy. However, MD adherence remains low among children and adolescents, necessitating targeted interventions to promote healthier dietary habits. Future high-quality intervention studies are necessary to elucidate the specific impact of the MD on inflammation in diverse pediatric populations with obesity and associated comorbidities.

Achieving healthy aging through gut microbiota-directed dietary intervention: Focusing on microbial biomarkers and host mechanisms

BACKGROUND

Population aging has become a primary global public health issue, and the prevention of age-associated diseases and prolonging healthy life expectancies are of particular importance. Gut microbiota has emerged as a novel target in various host physiological disorders including aging. Comprehensive understanding on changes of gut microbiota during aging, in particular gut microbiota characteristics of centenarians, can provide us possibility to achieving healthy aging or intervene pathological aging through gut microbiota-directed strategies.

AIM OF REVIEW

This review aims to summarize the characteristics of the gut microbiota associated with aging, explore potential biomarkers of aging and address microbiota-associated mechanisms of host aging focusing on intestinal barrier and immune status. By summarizing the existing effective dietary strategies in aging interventions, the probability of developing a diet targeting the gut microbiota in future is provided.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review is focused on three key notions: Firstly, gut microbiota has become a new target for regulating health status and lifespan, and its changes are closely related to age. Thus, we summarized aging-associated gut microbiota features at the levels of key genus/species and important metabolites through comparing the microbiota differences among centenarians, elderly people and younger people. Secondly, exploring microbiota biomarkers related to aging and discussing future possibility using dietary regime/components targeted to aging-related microbiota biomarkers promote human healthy lifespan. Thirdly, dietary intervention can effectively improve the imbalance of gut microbiota related to aging, such as probiotics, prebiotics, and postbiotics, but their effects vary among.

The interaction between Mediterranean diet and intestinal microbiome: relevance for preventive strategies against frailty in older individuals

Age-related changes in intestinal microbiome composition and function are increasingly recognized as pivotal in the pathophysiology of aging and are associated with the aging phenotype. Diet is a major determinant of gut-microbiota composition throughout the entire lifespan, and several of the benefits of a healthy diet in aging could be mediated by the microbiome. Mediterranean diet (MD) is a traditional dietary pattern regarded as the healthy diet paradigm, and a large number of studies have demonstrated its benefits in promoting healthy aging. MD has also a positive modulatory effect on intestinal microbiome, favoring bacterial taxa involved in the synthesis of several bioactive compounds, such as short-chain fatty acids (SCFAs), that counteract inflammation, anabolic resistance, and tissue degeneration. Intervention studies conducted in older populations have suggested that the individual response of older subjects to MD, in terms of reduction of frailty scores and amelioration of cognitive function, is significantly mediated by the gut-microbiota composition and functionality. In this context, the pathophysiology of intestinal microbiome in aging should be considered when designing MD-based interventions tailored to the needs of geriatric patients.

Microbial dysbiosis and the aging process: a review on the potential age-deceleration role of Lactiplantibacillus plantarum

Gut microbiota dysbiosis has been a serious risk factor for several gastric and systemic diseases. Recently, gut microbiota's role in aging was discussed. Available preclinical evidence suggests that the probiotic bacteria Lactiplantibacillus plantarums (LP) may influence the aging process via modulation of the gut microbiota. The present review summarized compelling evidence of LP's potential effect on aging hallmarks such as oxidative stress, inflammation, DNA methylation, and mitochondrial dysfunction. LP gavage modulates gut microbiota and improves overall endurance in aging animal models. LP cell constituents exert considerable antioxidant potential which may reduce ROS levels directly. In addition, restored gut microbiota facilitate a healthy intestinal milieu and accelerate multi-channel communication via signaling factors such as SCFA and GABA. Signaling factors further activate specific transcription factor Nrf2 in order to reduce oxidative damage. Nrf2 regulates cellular defense systems involving anti-inflammatory cytokines, MMPs, and protective enzymes against MAPKs. We concluded that LP supplementation may be an effective approach to managing aging and associated health risks.

Bazi Bushen capsule improves the deterioration of the intestinal barrier function by inhibiting NLRP3 inflammasome-mediated pyroptosis through microbiota-gut-brain axis

Purpose

The senescence-accelerated prone mouse 8 (SAMP8) is a widely used model for accelerating aging, especially in central aging. Mounting evidence indicates that the microbiota-gut-brain axis may be involved in the pathogenesis and progression of central aging-related diseases. This study aims to investigate whether Bazi Bushen capsule (BZBS) attenuates the deterioration of the intestinal function in the central aging animal model.

Methods

In our study, the SAMP8 mice were randomly divided into the model group, the BZ-low group (0.5 g/kg/d BZBS), the BZ-high group (1 g/kg/d BZBS) and the RAPA group (2 mg/kg/d rapamycin). Age-matched SAMR1 mice were used as the control group. Next, cognitive function was detected through Nissl staining and two-photon microscopy. The gut microbiota composition of fecal samples was analyzed by 16S rRNA gene sequencing. The Ileum tissue morphology was observed by hematoxylin and eosin staining, and the intestinal barrier function was observed by immunofluorescence. The expression of senescence-associated secretory phenotype (SASP) factors, including P53, TNF-α, NF-κB, IL-4, IL-6, and IL-10 was measured by real-time quantitative PCR. Macrophage infiltration and the proliferation and differentiation of intestinal cells were assessed by immunohistochemistry. We also detected the inflammasome and pyroptosis levels in ileum tissue by western blotting.

Results

BZBS improved the cognitive function and neuronal density of SAMP8 mice. BZBS also restored the intestinal villus structure and barrier function, which were damaged in SAMP8 mice. BZBS reduced the expression of SASP factors and the infiltration of macrophages in the ileum tissues, indicating a lower level of inflammation. BZBS enhanced the proliferation and differentiation of intestinal cells, which are essential for maintaining intestinal homeostasis. BZBS modulated the gut microbiota composition, by which BZBS inhibited the activation of inflammasomes and pyroptosis in the intestine.

Conclusion

BZBS could restore the dysbiosis of the gut microbiota and prevent the deterioration of intestinal barrier function by inhibiting NLRP3 inflammasome-mediated pyroptosis. These results suggested that BZBS attenuated the cognitive aging of SAMP8 mice, at least partially, by targeting the microbiota-gut-brain axis.

Beneficial effect of GABA-rich fermented milk whey on nervous system and intestinal microenvironment of aging mice induced by D-galactose

This study aims to investigate the protective effect of a freeze-dried powder prepared from a fermentation milk whey containing a high-yield GABA strain (FDH-GABA) against D-galactose-induced brain injury and gut microbiota imbalances in mice by probing changes to the PI3K/AKT/mTOR signaling pathway. A prematurely aged mouse model was established by performing the subcutaneous injection of D-galactose. Subsequently, the effects of FDH-GABA on the nervous system and intestinal microenvironment of the mice were explored by measuring their antioxidant activities, anti-inflammatory state, autophagy, pathway-related target protein expression levels, and intestinal microorganisms. Compared to the D-gal group, FDH-GABA improved the levels of SOD, T-AOC, IL-10, and neurotransmitters, while it reduced the contents of MDA and TNF-α. FDH-GABA also promoted autophagy and inhibited the PI3K/AKT/mTOR signaling pathway in the brains of the aged mice. Moreover, FDH-GABA restored the diversity of their intestinal flora. Pathological observations indicated that FDH-GABA was protective against damage to the brain and intestine of D-galactose-induced aging mice. These results reveal that FDH-GABA not only improved antioxidant stress, attenuated inflammation, restored the neurotransmitter content, and protected the tissue structure of the intestine and brain, but also effectively improved their intestinal microenvironment. The ameliorative effect of FDH-GABA on premature aging showed a clear dose-response relationship, and at the same time, the changes of intestinal microorganisms showed a certain correlation with the relevant indexes of nervous system. These findings provide insight into the effect of the FDH-GABA intervention on aging, providing a novel means for alleviating detrimental neurodegenerative changes in the aging population.

The influence of the gut microbiome on ovarian aging

Ovarian aging occurs prior to the aging of other organ systems and acts as the pacemaker of the aging process of multiple organs. As life expectancy has increased, preventing ovarian aging has become an essential goal for promoting extended reproductive function and improving bone and genitourinary conditions related to ovarian aging in women. An improved understanding of ovarian aging may ultimately provide tools for the prediction and mitigation of this process. Recent studies have suggested a connection between ovarian aging and the gut microbiota, and alterations in the composition and functional profile of the gut microbiota have profound consequences on ovarian function. The interaction between the gut microbiota and the ovaries is bidirectional. In this review, we examine current knowledge on ovary-gut microbiota crosstalk and further discuss the potential role of gut microbiota in anti-aging interventions. Microbiota-based manipulation is an appealing approach that may offer new therapeutic strategies to delay or reverse ovarian aging.

Impacts of gut microbiota alteration on age-related chronic liver diseases

The gut microbiome and its metabolites are involved in developing and progressing liver disease. Various liver illnesses, such as non-alcoholic fatty liver disease, alcoholic liver disease, hepatitis C, and hepatocellular carcinoma, are made worse and have worse prognoses with aging. Dysbiosis, which occurs when the symbiosis between the microbiota and the host is disrupted, can significantly negatively impact health. Liver disease is linked to qualitative changes, such as an increase in hazardous bacteria and a decrease in good bacteria, as well as quantitative changes in the overall amount of bacteria (overgrowth). Intestinal gut microbiota and their metabolites may lead to chronic liver disease development through various mechanisms, such as increasing gut permeability, persistent systemic inflammation, production of SCFA, bile acids, and alteration in metabolism. Age-related gut dysbiosis can disrupt the communication between gut microbiota and the host, impacting the host's health and lifespan. With aging, a gradual loss of the ability to maintain homeostasis because of structural alteration and gut dysbiosis leads to the disease progression in end-stage liver disease. Recently chronic liver disease has been identified as a global problem. A large number of patients are receiving liver transplants yearly. Thereby gut microbiome ecology is changing in the patients of the gut due to the changes in pathophysiology during the preoperative stage. The present review summarises the age-associated dysbiosis of gut microbial composition and its contribution to chronic liver disease. This review also provides information about the impact of liver transplant on the gut microbiome and possible disadvantageous effects of alteration in gut microbiota.

Astaxanthin, Haematococcus pluvialis and Haematococcus pluvialis Residue Alleviate Liver Injury in D-Galactose-induced Aging Mice through Gut-liver Axis

Astaxanthin is a keto-based carotenoid mainly obtained from marine organisms, like Haematococcus pluvialis (H. pluvialis). Previous studies indicated the protective effects of Astaxanthin and H. pluvialis on aging related oxidative injury in liver, while the potential mechanisms are largely unknown. In addition, H. pluvialis residue is a by-product after astaxanthin extraction, which is rarely studied and utilized. The present study aimed to compare the effects of astaxanthin, H. pluvialis and H. pluvialis residue on the oxidant injury of liver in D-galactose-induced aging mice and explore the potential mechanisms through gut-liver axis. The results showed that all the three supplements prevented D-galactose-induced tissue injury, oxidative stress and chronic inflammation in liver and improved liver function. Gut microbiota analysis indicated that astaxanthin notably increased fecal levels of Bacteroidetes, unclassified_f__ Lachnospiraceae, norank_f__Lachnospiraceae, norank_f__norank_o__Clostridia_UCG-014, Prevotellaceae_ UCG-001, unclassified_f__Prevotellaceae in D-galactose-fed mice (p < 0.05). Compared to aging mice, H. pluvialis group had higher fecal levels of norank_f__Lachnospiraceae and Lachnospiraceae_UCG-006 (p < 0.05). H. pluvialis residue group displayed higher relative levels of Bacteroidetes, Streptococcus, and Rikenellaceae_RC9_gut_group (p < 0.05). Moreover, the production of fecal microbial metabolites, like SCFAs and LPS was also differently restored by the three supplements. Overall, our results suggest astaxanthin, H. pluvialis and H. pluvialis residue could prevent aging related hepatic injury through gutliver axis and provide evidence for exploiting of H. pluvialis residue as a functional ingredient for the treatment of liver diseases. Future studies are needed to further clarify the effect and mechanism of dominant components of H. pluvialis residue on liver injury, which is expected to provide a reference for the high-value utilization of H. pluvialis resources.

The preliminary evidence on the association of the gut microbiota with stroke risk stratification in South Chinese population

Aims

This study aimed to investigate the association between the gut microbiota and the risk of stroke.

Methods

Faecal samples from 60 participants in South China, including 45 individuals with risk factors for stroke and 15 healthy controls, were collected and subjected to 16S rRNA sequencing. A bioinformatics analysis was performed to characterise the gut microbial diversity and taxonomic compositions at different risk levels (low, moderate, and high) of stroke. Functional prediction and correlation analyses between the microbiota and laboratory markers were performed to explore the potential mechanisms.

Results

A significant difference in beta diversity was observed between the participants from the stroke risk and healthy control groups. Linear discriminant effect size analysis revealed a large number of vascular beneficial bacteria enriched in the participants from the healthy control and low-risk groups, but a few vascular harmful bacteria were more abundant in the participants from the high-risk group than in those from the other groups. In addition, Anaerostipes, Clostridium_XlVb, and Flavonifractor, all of which belonged to the Firmicutes phylum, were enriched in the participants from the low-risk group, and their relative abundances gradually decreased as the stroke risk increased. Spearman's analysis revealed that these outstanding microbiota correlated with the levels of triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, white blood cells, neutrophils, and carotid intima-media thickness.

Conclusion

The preliminary evidence suggests that gut microbiota is associated with stroke risk. It potentially ameliorates atherosclerosis by targeting lipid metabolism and inflammation. This provides novel insights into the early screening of stroke risk and primary prevention.

Characteristics of the gut microbiome and metabolic profile in elderly patients with sarcopenia

Introduction: There is growing evidence of research indicating that the gut microbiota is involved in the development of sarcopenia. Nevertheless, there exists a notable deficiency in comprehension concerning the connection between irregularities in the intestinal microbiome and metabolic processes in older individuals suffering from sarcopenia. Methods: To analyze fecal samples obtained from a cohort of 30 older patients diagnosed with sarcopenia as well as 30 older patients without sarcopenia, this study employed 16S rDNA sequencing and liquid chromatography-mass spectrometry (LC-MS)-based non-targeted metabolomics profiling techniques. Results: As a result, we found that 29 genera and 172 metabolites were significantly altered in the sarcopenic patients. Among them, Blautia, Lachnospiraceae_unclassified, and Subdoligranulum were the bacteria with a potential diagnostic value for sarcopenia diagnosis. Correlation analysis between clinical indices and these gut bacteria suggested that the IL-6 level was negatively correlated with Blautia. Function prediction analysis demonstrated that 17 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways differ significantly between sarcopenic and non-sarcopenic patients. The primary classes of metabolites identified in the study included lipids and lipid-like molecules, organic acids and derivatives, and organoheterocyclic compounds. KEGG enrichment analysis showed that purine metabolism, arginine and proline metabolism, alanine, aspartate, and glutamate metabolism, butanoate metabolism, and histidine metabolism may contribute to the development of sarcopenia. The correlation study on gut microbiota and metabolites found that Lachnospiraceae_unclassified was positively associated with seven metabolites that were more abundant in the non-sarcopenia group and negatively correlated with three metabolites that were more abundant in the sarcopenia group. In addition, Subdoligranulum was positively correlated with seven metabolites that were lacking in sarcopenia and negatively correlated with two metabolites that were enriching in sarcopenia. Moreover, Blautia was positively associated with xanthosine. Discussion: We conducted a study on the intestinal microbiota and metabolic profile of elderly individuals with sarcopenia, offering a comprehensive analysis of the overall ecosystem. Through this investigation, we were able to validate existing research on the gut-muscle axis and further investigate potential pathogenic processes and treatment options for sarcopenia.

Probiotic supplementation has sex-dependent effects on immune responses in association with the gut microbiota in community-dwelling older adults: a randomized, double-blind, placebo-controlled, multicenter trial

BACKGROUND/OBJECTIVES

Probiotics have been suggested as potent modulators of age-related disorders in immunological functions, yet little is known about sex-dependent effects of probiotic supplements. Therefore, we aimed to investigate sex-dependent effects of probiotics on profiles of the gut microbiota and peripheral immune cells in healthy older adults.

SUBJECTS/METHODS

In a randomized, double-blind, placebo-controlled, multicenter trial, healthy elderly individuals ≥ 65 yrs old were administered probiotic capsules (or placebo) for 12 wk. Gut microbiota was analyzed using 16S rRNA gene sequencing and bioinformatic analyses. Peripheral immune cells were profiled using flow cytometry for lymphocytes (natural killer, B, CD4+ T, and CD8+ T cells), dendritic cells, monocytes, and their subpopulations.

RESULTS

Compared with placebo, phylum Firmicutes was significantly reduced in the probiotic group in women, but not in men. At the genus level, sex-specific responses included reductions in the relative abundances of pro-inflammatory gut microbes, including Catabacter and unclassified_Coriobacteriales, and Burkholderia and unclassified Enterobacteriaceae, in men and women, respectively. Peripheral immune cell profiling analysis revealed that in men, probiotics significantly reduced the proportions of dendritic cells and CD14+ CD16- monocytes; however, these effects were not observed in women. In contrast, the proportion of total CD4+ T cells was significantly reduced in women in the probiotic group. Additionally, serum lipopolysaccharide-binding protein levels showed a decreasing tendency that were positively associated with changes in gut bacteria, including Catabacter (ρ = 0.678, P < 0.05) and Burkholderia (ρ = 0.673, P < 0.05) in men and women, respectively.

CONCLUSIONS

These results suggest that probiotic supplementation may reduce the incidence of inflammation-related diseases by regulating the profiles of the gut microbiota and peripheral immune cells in healthy elders in a sex-specific manner.

A Pectic Polysaccharide from Codonopsis pilosula Alleviates Inflammatory Response and Oxidative Stress of Aging Mice via Modulating Intestinal Microbiota-Related Gut-Liver Axis

Aging is a biological process that leads to the progressive deterioration and loss of physiological functions in the human body and results in an increase in morbidity and mortality, and aging-related disease is a major global problem that poses a serious threat to public health. Polysaccharides have been shown to delay aging by reducing oxidative damage, suppressing inflammatory responses, and modulating intestinal microbiota. Our previous studies have shown that polysaccharide CPP-1 extracted from the root of Codonopsis pilosula possesses noticeable anti-oxidant activity in vitro. Thus, in our study, we tested the anti-aging effect of CPP-1 in naturally aging mice (in vivo). Eighteen C57/BL mice (48-week-old, male) were divided into a control group, high-dose CPP-1 group (20 mg/mL), and low-dose CPP-1 group (10 mg/mL). We discovered that CPP-1 can exert a reparative effect on aging stress in the intestine and liver, including alleviating inflammation and oxidative damage. We revealed that CPP-1 supplementation improved the intestinal microbiota composition and repaired the intestinal barrier in the gut. Furthermore, CPP-1 was proved to modulate lipid metabolism and repair hepatocyte injury in the liver by influencing the enterohepatic axis associated with the intestinal microbiota. Therefore, we concluded that CPP-1 prevents and alleviates oxidative stress and inflammatory responses in the intestine and liver of aging mice by modulating the intestinal microbiota-related gut-liver axis to delay aging.

Treating Leaky Syndrome in the Over 65s: Progress and Challenges

As we age, our organ functions gradually decline. Circulating factors in the blood and the integrity of organ barriers can become dysfunctional, resulting in a condition known as leaky syndrome. This condition involves the unregulated exchange or leakage of components between organs. However, the triggers of leaky syndrome, as well as its role in aging-related disorders and illnesses, remain largely unknown. In this editorial, we discuss potential mechanisms that originate from the gut and resident microbes (microbiome) to contribute in leaky syndrome. Furthermore, we explore how the food we consume can impact the development of leaky syndrome, potentially influencing the biology of aging and challenges to diagnose the leaky gut condition accurately and clinically.

The Possible Role of Probiotic Supplementation in Inflammation: A Narrative Review

The fine balance between symbiotic and potentially opportunistic and/or pathogenic microorganisms can undergo quantitative alterations, which, when associated with low intestinal biodiversity, could be responsible for the development of gut inflammation and the so-called "intestinal dysbiosis". This condition is characterized by the disbalance of a fine synergistic mechanism involving the mucosal barrier, the intestinal neuroendocrine system, and the immune system that results in an acute inflammatory response induced by different causes, including viral or bacterial infections of the digestive tract. More frequently, however, dysbiosis is induced slowly and subtly by subliminal causal factors, resulting in a chronic condition related to different diseases affecting the digestive tract and other organs and apparatuses. Studies on animal models, together with studies on humans, highlight the significant role of the gut microbiota and microbiome in the occurrence of inflammatory conditions such as metabolic syndrome and cardiovascular diseases (CVDs); neurodegenerative, urologic, skin, liver, and kidney pathologies; and premature aging. The blood translocation of bacterial fragments has been found to be one of the processes linked to gut dysbiosis and responsible for the possible occurrence of "metabolic endotoxemia" and systemic inflammation, associated with an increased risk of oxidative stress and related diseases. In this context, supplementation with different probiotic strains has been shown to restore gut eubiosis, especially if administered in long-term treatments. The aim of this review is to describe the anti-inflammatory effects of specific probiotic strains observed in clinical trials and the respective indications, highlighting the differences in efficacy depending on strain, formulation, time and duration of treatment, and dosage used.

Microbial-Immune Crosstalk in Elderly-Onset Inflammatory Bowel Disease: Unchartered Territory

Elderly-onset inflammatory bowel disease [IBD] patients exhibit a distinct natural history compared to younger IBD patients, with unique disease phenotypes, differential responses to therapy, and increased surgical morbidity and mortality. Despite the foreseeable high demand for personalized medicine and specialized IBD care in the elderly, current paradigms of IBD management fail to capture the required nuances of care for elderly-onset IBD patients. Our review postulates the roles of systemic and mucosal immunosenescence, inflammageing and a dysbiotic microbial ecosystem in the pathophysiology of elderly-onset IBD. Ultimately, a better understanding of elderly-onset IBD can lead to improved patient outcomes and the tailoring of future preventative and treatment strategies.

Gut Microbiota and Aging: Traditional Chinese Medicine and Modern Medicine

The changing composition of gut microbiota, much like aging, accompanies people throughout their lives, and the inextricable relationship between both has recently attracted extensive attention as well. Modern medical research has revealed that a series of changes in gut microbiota are involved in the aging process of organisms, which may be because gut microbiota modulates aging-related changes related to innate immunity and cognitive function. At present, there is no definite and effective method to delay aging. However, Nobel laureate Tu Youyou's research on artemisinin has inspired researchers to study the importance of Traditional Chinese Medicine (TCM). TCM, as an ancient alternative medicine, has unique advantages in preventive health care and in treating diseases as it already has formed an independent understanding of the aging system. TCM practitioners believe that the mechanism of aging is mainly deficiency, and pathological states such as blood stasis, qi stagnation and phlegm coagulation can exacerbate the process of aging, which involves a series of organs, including the brain, kidney, heart, liver and spleen. Our current understanding of aging has led us to realise that TCM can indeed make some beneficial changes, such as the improvement of cognitive impairment. However, due to the multi-component and multi-target nature of TCM, the exploration of its mechanism of action has become extremely complex. While analysing the relationship between gut microbiota and aging, this review explores the similarities and differences in treatment methods and mechanisms between TCM and Modern Medicine, in order to explore a new approach that combines TCM and Modern Medicine to regulate gut microbiota, improve immunity and delay aging.

Gut microbiota and anti-aging: Focusing on spermidine

The human gut microbiota plays numerous roles in regulating host growth, the immune system, and metabolism. Age-related changes in the gut environment lead to chronic inflammation, metabolic dysfunction, and illness, which in turn affect aging and increase the risk of neurodegenerative disorders. Local immunity is also affected by changes in the gut environment. Polyamines are crucial for cell development, proliferation, and tissue regeneration. They regulate enzyme activity, bind to and stabilize DNA and RNA, have antioxidative properties, and are necessary for the control of translation. All living organisms contain the natural polyamine spermidine, which has anti-inflammatory and antioxidant properties. It can regulate protein expression, prolong life, and improve mitochondrial metabolic activity and respiration. Spermidine levels experience an age-related decrease, and the development of age-related diseases is correlated with decreased endogenous spermidine concentrations. As more than just a consequence, this review explores the connection between polyamine metabolism and aging and identifies advantageous bacteria for anti-aging and metabolites they produce. Further research is being conducted on probiotics and prebiotics that support the uptake and ingestion of spermidine from food extracts or stimulate the production of polyamines by gut microbiota. This provides a successful strategy to increase spermidine levels.

Sleep duration trajectories and all-cause mortality among Chinese elderly: A community-based cohort study

BACKGROUND

China is among the largest and fastest aging countries. The elderly population is more vulnerable, with higher proportion of inappropriate sleep duration and risk of mortality, compared with young and middle-aged adults. Single-measured sleep duration has been associated with mortality, but the health effects of long-term sleep duration trajectories remain unknown. This study aimed to explore the prospective associations between sleep duration trajectories and all-cause mortality among Chinese elderly.

METHODS

Participants (n = 3,895; median age: 82 years; females: 53.3%) who reported sleep duration in all three surveys (2005, 2008, and 2011) from the community-based Chinese Longitudinal Healthy Longevity Survey (CLHLS) were followed up until 2019 (about 8 years). We identified sleep duration trajectories by latent class mixed model and explored their association with all-cause mortality using Cox hazard proportional regression and Laplace regression models. Further, stratified analysis by demographic characteristics and lifestyles and sensitivity analysis by lag effect, health-related factors, and inverse probability weighting were used to verify the robustness of the association. In addition, we explored the threshold effect of baseline sleep duration on the risk of all-cause mortality.

RESULTS

We documented 1,881 all-cause deaths during 16,689 person-years of follow-up. Five sleep duration trajectories were identified: moderately increased trajectory (28.1%), rapidly increased trajectory (7.2%), persistent sleep trajectory of 7 h (33.7%), moderately decreased trajectory (21.3%), and rapidly decreased trajectory (9.7%). Compared with the persistent sleep trajectory of 7 h, the multivariable-adjusted HRs (95%CI) for moderately increased trajectory, rapidly increased trajectory, moderately decreased trajectory, and rapidly decreased trajectory were 1.21 (1.08, 1.36), 1.21 (1.01, 1.44), 0.95 (0.82, 1.10), and 0.93 (0.78, 1.11), respectively; and the corresponding difference in median survival time (95%CI) were -0.53 (-1.01, -0.05), -0.43 (0.16, -1.02), 0.26 (-0.34, 0.86), and 0.25 (-0.51, 1.02), respectively. Stratified and sensitivity analyses showed consistent results. Threshold analysis indicated a sharply increased risk of mortality in participants whose sleep exceeds 9 h (HR = 1.20, 95%CI: 1.11, 1.30).

CONCLUSION

Compared with the persistent sleep trajectory of 7 h, moderately and rapidly increased sleep duration trajectories were associated with higher subsequent mortality in Chinese elderly. Those who report sleep exceeding 9 h may be at high risk for all-cause mortality.

The possible role of gut microbiota dysbiosis in the pathophysiology of delirium in older persons

Delirium is a clinical syndrome characterized by an acute change in attention, awareness and cognition with fluctuating course, frequently observed in older patients during hospitalization for acute medical illness or after surgery. Its pathogenesis is multifactorial and still not completely understood, but there is general consensus on the fact that it results from the interaction between an underlying predisposition, such as neurodegenerative diseases, and an acute stressor acting as a trigger, such as infection or anesthesia. Alterations in brain insulin sensitivity and metabolic function, increased blood-brain barrier permeability, neurotransmitter imbalances, abnormal microglial activation and neuroinflammation have all been involved in the pathophysiology of delirium. Interestingly, all these mechanisms can be regulated by the gut microbiota, as demonstrated in experimental studies investigating the microbiota-gut-brain axis in dementia. Aging is also associated with profound changes in gut microbiota composition and functions, which can influence several aspects of disease pathophysiology in the host. This review provides an overview of the emerging evidence linking age-related gut microbiota dysbiosis with delirium, opening new perspectives for the microbiota as a possible target of interventions aimed at delirium prevention and treatment.

Gut microbiome dysbiosis in Alzheimer's disease and mild cognitive impairment: A systematic review and meta-analysis

BACKGROUND

Alzheimer's disease (AD) is a neurodegenerative disorder that causes gradual memory loss. AD and its prodromal stage of mild cognitive impairment (MCI) are marked by significant gut microbiome perturbations, also known as gut dysbiosis. However, the direction and extent of gut dysbiosis have not been elucidated. Therefore, we performed a meta-analysis and systematic review of 16S gut microbiome studies to gain insights into gut dysbiosis in AD and MCI.

METHODS

We searched MEDLINE, Scopus, EMBASE, EBSCO, and Cochrane for AD gut microbiome studies published between Jan 1, 2010 and Mar 31, 2022. This study has two outcomes: primary and secondary. The primary outcomes explored the changes in α-diversity and relative abundance of microbial taxa, which were analyzed using a variance-weighted random-effects model. The secondary outcomes focused on qualitatively summarized β-diversity ordination and linear discriminant analysis effect sizes. The risk of bias was assessed using a methodology appropriate for the included case-control studies. The geographic cohorts' heterogeneity was examined using subgroup meta-analyses if sufficient studies reported the outcome. The study protocol has been registered with PROSPERO (CRD42022328141).

FINDINGS

Seventeen studies with 679 AD and MCI patients and 632 controls were identified and analyzed. The cohort is 61.9% female with a mean age of 71.3±6.9 years. The meta-analysis shows an overall decrease in species richness in the AD gut microbiome. However, the phylum Bacteroides is consistently higher in US cohorts (standardised mean difference [SMD] 0.75, 95% confidence interval [CI] 0.37 to 1.13, p < 0.01) and lower in Chinese cohorts (SMD -0.79, 95% CI -1.32 to -0.25, p < 0.01). Moreover, the Phascolarctobacterium genus is shown to increase significantly, but only during the MCI stage.

DISCUSSION

Notwithstanding possible confounding from polypharmacy, our findings show the relevance of diet and lifestyle in AD pathophysiology. Our study presents evidence for region-specific changes in abundance of Bacteroides, a major constituent of the microbiome. Moreover, the increase in Phascolarctobacterium and the decrease in Bacteroides in MCI subjects shows that gut microbiome dysbiosis is initiated in the prodromal stage. Therefore, studies of the gut microbiome can facilitate early diagnosis and intervention in Alzheimer's disease and perhaps other neurodegenerative disorders.

Accounting Gut Microbiota as the Mediator of Beneficial Effects of Dietary (Poly)phenols on Skeletal Muscle in Aging

Sarcopenia, the age-related loss of muscle mass and function increasing the risk of disability and adverse outcomes in older people, is substantially influenced by dietary habits. Several studies from animal models of aging and muscle wasting indicate that the intake of specific polyphenol compounds can be associated with myoprotective effects, and improvements in muscle strength and performance. Such findings have also been confirmed in a smaller number of human studies. However, in the gut lumen, dietary polyphenols undergo extensive biotransformation by gut microbiota into a wide range of bioactive compounds, which substantially contribute to bioactivity on skeletal muscle. Thus, the beneficial effects of polyphenols may consistently vary across individuals, depending on the composition and metabolic functionality of gut bacterial communities. The understanding of such variability has recently been improved. For example, resveratrol and urolithin interaction with the microbiota can produce different biological effects according to the microbiota metabotype. In older individuals, the gut microbiota is frequently characterized by dysbiosis, overrepresentation of opportunistic pathogens, and increased inter-individual variability, which may contribute to increasing the variability of biological actions of phenolic compounds at the skeletal muscle level. These interactions should be taken into great consideration for designing effective nutritional strategies to counteract sarcopenia.

Extraction, bioactive function and application of wheat germ protein/peptides: A review

The aging population and high incidence of age-related diseases are major global societal issues. Consuming bioactive substances as part of our diet is increasingly recognized as essential for ensuring a healthy life for older adults. Wheat germ protein has a reasonable peptide structure and amino acid ratio but has not been fully utilized and exploited, resulting in wasted wheat germ resources. This review summarizes reformational extraction methods of wheat germ protein/peptides (WGPs), of which different methods can be selected to obtain various WGPs. Interestingly, except for some bioactive activities found earlier, WGPs display potential anti-aging activity, with possible mechanisms including antioxidant, immunomodulatory and intestinal flora regulation. However, there are missing in vitro and in vivo bioactivity assessments of WGPs. WGPs possess physicochemical properties of good foamability, emulsification and water retention and are used as raw materials or additives to improve food quality. Based on the above, further studies designing methods to isolate particular types of WGPs, determining their nutritional and bioactive mechanisms and verifying their activity in vivo in humans are crucial for using WGPs to improve human health.

Impact of auricular percutaneous electrical nerve field stimulation on gut microbiome in adolescents with irritable bowel syndrome: A pilot study

OBJECTIVES

Percutaneous electrical nerve field stimulation (PENFS) has documented efficacy for irritable bowel syndrome (IBS) via plausible vagal neuromodulation effects. The vagus nerve may affect gut microbiome composition via brain-gut-microbiome signaling. We aimed to investigate gut microbiome alterations by PENFS therapy in adolescent IBS patients.

METHODS

A prospective study of females with IBS aged 11-18 years receiving PENFS therapy for 4 weeks with pre- and post-intervention stool sampling was conducted. Outcome surveys completed pre-therapy, weekly, and post-therapy included IBS-Severity Scoring System (IBS-SSS), Visceral Sensitivity Index (VSI), Functional Disability Inventory (FDI), and the global symptom response scale (SRS). Bacterial DNA was extracted from stool samples followed by 16S rRNA amplification and sequencing. QIIME 2 (version 2022.2) was used for analyses of α and β diversity and differential abundance by group.

RESULTS

Twenty females aged 15.6 ± 1.62 years were included. IBS-SSS, VSI, and FDI scores decreased significantly after PENFS therapy (P < 0.0001, P = 0.0003, P = 0.0004, respectively). No intra- or interindividual microbiome changes were noted pre- versus post-therapy or between responders and non-responders. When response was defined by 50-point IBS-SSS score reduction, α diversity was higher in responders compared with non-responders at week 4 (P = 0.033). There was higher abundance of Blautia in excellent responders versus non-responders.

CONCLUSIONS

There were no substantial microbial diversity alterations with PENFS. Subjects with excellent therapeutic response showed an enrichment of relative abundance of Blautia, which may indicate that patients with specific microbial signature have a more favorable response to PENFS.

Mining chicken ileal microbiota for immunomodulatory microorganisms

The gut microbiota makes important contributions to host immune system development and resistance to pathogen infections, especially during early life. However, studies addressing the immunomodulatory functions of gut microbial individuals or populations are limited. In this study, we explore the systemic impact of the ileal microbiota on immune cell development and function of chickens and identify the members of the microbiota involved in immune system modulation. We initially used a time-series design with six time points to prove that ileal microbiota at different succession stages is intimately connected to immune cell maturation. Antibiotics perturbed the microbiota succession and negatively affected immune development, whereas early exposure to the ileal commensal microbiota from more mature birds promoted immune cell development and facilitated pathogen elimination after Salmonella Typhimurium infection, illustrating that early colonization of gut microbiota is an important driver of immune development. Five bacterial strains, Blautia coccoides, Bacteroides xylanisolvens, Fournierella sp002159185, Romboutsia lituseburensis, and Megamonas funiformis, which are closely related to the immune system development of broiler chickens, were then screened out and validated for their immunomodulatory properties. Our results provide insight into poultry immune system-microbiota interactions and also establish a foundation for targeted immunological interventions aiming to combat infectious diseases and promote poultry health and production.

Probiotic Fermentation of Kelp Enzymatic Hydrolysate Promoted its Anti-Aging Activity in D-Galactose-Induced Aging Mice by Modulating Gut Microbiota

SCOPE

To investigate anti-aging effects of probiotic-fermented kelp enzymatic hydrolysate culture (KMF), probiotic-fermented kelp enzymatic hydrolysate supernatant (KMFS), and probiotic-fermented kelp enzymatic hydrolysate bacteria suspension (KMFP) in D-galactose-induced aging mice.

METHODS AND RESULTS

The study uses a probiotic-mixture of Lactobacillus reuteri, Pediococcus pentosaceus, and Lactobacillus acidophilus strains for kelp fermentation. KMF, KMFS, and KMFP prevent D-galactose-induced elevation of malondialdehyde levels in serum and brain tissue of aging mice, and they increase superoxide dismutase and catalase levels and total antioxidant capacity. Furthermore, they improve the cell structure of mouse brain, liver, and intestinal tissue. Compared with the model control group, the KMF, KMFS, and KMFP treatments regulate mRNA and protein levels of genes associated with aging, the concentrations of acetic acid, propionic acid, and butyric acid in the three treatment groups are more than 1.4-, 1.3-, and 1.2-fold increased, respectively. Furthermore, the treatments affect the gut microbiota community structures.

CONCLUSIONS

These results suggest that KMF, KMFS, and KMFP can modulate gut microbiota imbalances and positively affect aging-related genes to achieve anti-aging effects.

The therapeutic potential for senescence-associated diabetes of green alga Enteromorpha prolifera polysaccharide

DEAE-52 and Sephadex G-100 columns were used to isolate Enteromorpha prolifera polysaccharide (EPP), which contains α-L-Rhap-(1 → 4)-α-L-Arap-(1 → 2)-α-L-Rhap-(1 → 3)-β-D-Galp-(1 → structural fragment, along with α-L-Rhap-(1 → and →2)-α-L-Rhap-(1 → 3)-β-D-GlcpA-(1 → side bonds that connect to →3,6)-β-D-Galp-(1→. The anti-ageing and hypoglycemic activities of EPP were assessed using an ageing diabetic mice model, and the revealed that EPP could improve glucose metabolism-associated parameters and inhibit the expression of ageing associated genes, including p16^INK4a, p38 MAPK, NOX-1, VEGF, and AGER, thus preventing liver damage. Moreover, gut microbiota profiling revealed that EPP significantly increased the abundances of o_Lactobacillaceae, c_Bacilli, f_Lactobacillaceae, g_Lactobacillus, and p_Firmicutes, showing that EPP has a probiotic effect on enhancing the beneficial microbiota in ageing diabetic mice. In summary, EPP might serve as a potential bioactive compound to alleviate hyperglycaemia and ageing in diabetic in mice and further clinical studies are required to verify these effects.

Immunity orchestrates a bridge in gut-brain axis of neurodegenerative diseases

Neurodegenerative diseases, in particular for Alzheimer's disease (AD), Parkinson's disease (PD) and Multiple sclerosis (MS), are a category of diseases with progressive loss of neuronal structure or function (encompassing neuronal death) leading to neuronal dysfunction, whereas the underlying pathogenesis remains to be clarified. As the microbiological ecosystem of the intestinal microbiome serves as the second genome of the human body, it is strongly implicated as an essential element in the initiation and/or progression of neurodegenerative diseases. Nevertheless, the precise underlying principles of how the intestinal microflora impact on neurodegenerative diseases via gut-brain axis by modulating the immune function are still poorly characterized. Consequently, an overview of initiating the development of neurodegenerative diseases and the contribution of intestinal microflora on immune function is discussed in this review.