Interactions Between the Aging Gut Microbiome and Common Geriatric Giants: Polypharmacy, Frailty, and Dementia

Comparison of the gut microbiota in older people with and without sarcopenia: a systematic review and meta-analysis

Introduction

Sarcopenia, an age-related disorder marked by decreased skeletal muscle mass, strength, and function, is associated with negative health impacts in individuals and financial burdens on families and society. Studies have suggested that age-related alterations in gut microbiota may contribute to the development of sarcopenia in older people through the gut-muscle axis, thus modulation of gut microbiota may be a promising approach for sarcopenia treatment. However, the characteristic gut microbiota for sarcopenia has not been consistent across studies. Therefore, the aim of this study was to compare the diversity and compositional differences in the gut microbiota of older people with and without sarcopenia, and to identify gut microbiota biomarkers with therapeutic potential for sarcopenia.

Methods

The PubMed, Embase, Web of Science, Cochrane Library, China National Knowledge Infrastructure, and Wanfang Database were searched studies about the gut microbiota characteristics in older people with sarcopenia. The quality of included articles was assessed by the Newcastle-Ottawa Scale (NOS). Weighted standardized mean differences (SMDs) and 95% confidence intervals (CIs) for α-diversity index were estimated using a random effects model. Qualitative synthesis was conducted for β-diversity and the correlation between gut microbiota and muscle parameters. The relative abundance of the gut microbiota was analyzed quantitatively and qualitatively, respectively.

Results

Pooled estimates showed that α-diversity was significantly lower in older people with sarcopenia (SMD: -0.41, 95% CI: -0.57 to -0.26, I²: 71%, P < 0.00001). The findings of β-diversity varied across included studies. In addition, our study identified gut microbiota showing a potential and negative correlation with sarcopenia, such as Prevotella, Slackia, Agathobacter, Alloprevotella, Prevotella copri, Prevotellaceae sp., Bacteroides coprophilus, Mitsuokella multacida, Bacteroides massiliensis, Bacteroides coprocola Conversely, a potential and positive correlation was observed with opportunistic pathogens like Escherichia-Shigella, Eggerthella, Eggerthella lenta and Collinsella aerofaciens.

Discussion

This study showed that α-diversity is decreased in sarcopenia, probably predominantly due to diminished richness rather than evenness. In addition, although findings of β-diversity varied across included studies, the overall trend toward a decrease in SCFAs-producing bacteria and an increase in conditionally pathogenic bacteria. This study provides new ideas for targeting the gut microbiota for the prevention and treatment of sarcopenia.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/view/CRD42024573090, identifier CRD42024573090.

Antibiotic Resistance in the Elderly: Mechanisms, Risk Factors, and Solutions

Antibiotic resistance presents a critical challenge in healthcare, particularly among the elderly, where multidrug-resistant organisms (MDROs) contribute to increased morbidity, mortality, and healthcare costs. This review focuses on the mechanisms underlying resistance in key bacterial pathogens and highlights how aging-related factors like immunosenescence, frailty, and multimorbidity increase the burden of infections from MDROs in this population. Novel strategies to mitigate resistance include the development of next-generation antibiotics like teixobactin and cefiderocol, innovative therapies such as bacteriophage therapy and antivirulence treatments, and the implementation of antimicrobial stewardship programs to optimize antibiotic use. Furthermore, advanced molecular diagnostic techniques, including nucleic acid amplification tests and next-generation sequencing, allow for faster and more precise identification of resistant pathogens. Vaccine development, particularly through innovative approaches like multi-epitope vaccines and nanoparticle-based platforms, holds promise in preventing MDRO infections among the elderly. The role of machine learning (ML) in predicting resistance patterns and aiding in vaccine and antibiotic development is also explored, offering promising solutions for personalized treatment and prevention strategies in the elderly. By integrating cutting-edge diagnostics, therapeutic innovations, and ML-based approaches, this review underscores the importance of multidisciplinary efforts to address the global challenge of antibiotic resistance in aging populations.

Investigating the effects of synbiotic supplementation on functional movement, strength and muscle health in older Australians: a study protocol for a double-blind, randomized, placebo-controlled trial

BACKGROUND

Aging has been associated with a progressive loss of skeletal muscle quality, quantity and strength, which may result in a condition known as sarcopenia, leading to a decline in physical performance, loss of independence and reduced quality of life. While the cause of impaired physical functioning observed in elderly populations appears to be multifactorial, recent evidence suggests that age-associated alterations in gut microbiota could be a contributing factor. The primary objective will be to assess the effects of a dietary synbiotic formulation on sarcopenia-related functional outcomes such as handgrip strength, gait speed and physical performance within older individuals living independently. The secondary objective will be to examine associations between changes in gut microbiota composition, functional performance and lean muscle mass.

METHODS

Seventy-four elderly (60-85 years) participants will be randomized in a double-blind, placebo-controlled fashion to either an intervention or control group. The intervention group (n = 37) will receive oral synbiotic formulation daily for 16 weeks. The control group (n = 37) will receive placebo. Assessments of physical performance (including Short Physical Performance Battery, handgrip strength and timed up-and-go tests) and muscle ultrasonography will be performed at 4 time points (baseline and weeks 8, 16 and 20). Likewise, body composition via bioelectric impedance analysis and blood and stool samples will be collected at each time point. Dual-energy X-ray absorptiometry will be performed at baseline and week 16. The primary outcomes will be between-group changes in physical performance from baseline to 16 weeks. Secondary outcomes include changes in body composition, muscle mass and architecture, fecal microbiota composition and diversity, and fecal and plasma metabolomics.

DISCUSSION

Gut-modulating supplements appear to be effective in modifying gut microbiota composition in healthy older adults. However, it is unclear whether these changes translate into functional and/or health improvements. In the present study, we will investigate the effects of a synbiotic formulation on measures of physical performance, strength and muscle health in healthy older populations.

TRIAL REGISTRATION

This study was prospectively registered with the Australian New Zealand Clinical Trials Registry (ACTRN12622000652774) in May 2022.

The Role of Gut Microbiota in the Etiopathogenesis of Multiple Chronic Diseases

Chronic diseases (CD) may result from a combination of genetic factors, lifestyle and social behaviours, healthcare system influences, community factors, and environmental determinants of health. These risk factors frequently coexist and interact with one another. Ongoing research and a focus on personalized interventions are pivotal strategies for preventing and managing chronic disease outcomes. A wealth of literature suggests the potential involvement of gut microbiota in influencing host metabolism, thereby impacting various risk factors associated with chronic diseases. Dysbiosis, the perturbation of the composition and activity of the gut microbiota, is crucial in the etiopathogenesis of multiple CD. Recent studies indicate that specific microorganism-derived metabolites, including trimethylamine N-oxide, lipopolysaccharide and uremic toxins, contribute to subclinical inflammatory processes implicated in CD. Various factors, including diet, lifestyle, and medications, can alter the taxonomic species or abundance of gut microbiota. Researchers are currently dedicating efforts to understanding how the natural progression of microbiome development in humans affects health outcomes. Simultaneously, there is a focus on enhancing the understanding of microbiome-host molecular interactions. These endeavours ultimately aim to devise practical approaches for rehabilitating dysregulated human microbial ecosystems, intending to restore health and prevent diseases. This review investigates how the gut microbiome contributes to CD and explains ways to modulate it for managing or preventing chronic conditions.

Dynamic changes in butyrate levels regulate satellite cell homeostasis by preventing spontaneous activation during aging

The gut microbiota plays a pivotal role in systemic metabolic processes and in particular functions, such as developing and preserving the skeletal muscle system. However, the interplay between gut microbiota/metabolites and the regulation of satellite cell (SC) homeostasis, particularly during aging, remains elusive. We propose that gut microbiota and its metabolites modulate SC physiology and homeostasis throughout skeletal muscle development, regeneration, and aging process. Our investigation reveals that microbial dysbiosis manipulated by either antibiotic treatment or fecal microbiota transplantation from aged to adult mice, leads to the activation of SCs or a significant reduction in the total number. Furthermore, employing multi-omics (e.g., RNA-seq, 16S rRNA gene sequencing, and metabolomics) and bioinformatic analysis, we demonstrate that the reduced butyrate levels, alongside the gut microbial dysbiosis, could be the primary factor contributing to the reduction in the number of SCs and subsequent impairments during skeletal muscle aging. Meanwhile, butyrate supplementation can mitigate the antibiotics-induced SC activation irrespective of gut microbiota, potentially by inhibiting the proliferation and differentiation of SCs/myoblasts. The butyrate effect is likely facilitated through the monocarboxylate transporter 1 (Mct1), a lactate transporter enriched on membranes of SCs and myoblasts. As a result, butyrate could serve as an alternative strategy to enhance SC homeostasis and function during skeletal muscle aging. Our findings shed light on the potential application of microbial metabolites in maintaining SC homeostasis and preventing skeletal muscle aging.

The effects of the interplay between vitamins, antibiotics, and gut microbiota on the pathogenesis and progression of dementia: A systematic review and meta-analysis

Background

Given that there is already evidence of a neural network that connects the brain and gut and that the gut microbiota actively modulates gut health, it is crucial to know which foods, supplements, and medications to use or avoid when treating any disease that causes dementia or cognitive impairment. Previous research has examined the relationships between vitamins, antibiotics, and gut microbiota and the correlations between these factors and dementia. The question arises of how these three factors interact together and if evidence suggests one element is more important than the others in the pathogenesis and development of dementia.

Methods

The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) standards were followed when conducting this review. The papers' publication dates varied from (2012-2022). Cochrane/EMBASE, PEDro, and PubMed/Medline databases were searched. The precise terms "gut microbiota," vitamins," antibiotics," and "dementia" were included in the search method, along with the conjunctions "OR" and "AND."

Results

Gut dysbiosis has a significant impact on cognition, brain function, and the development and progression of dementia. The two most popular probiotics used in studies linked to cognition benefits were Lactobacillus and Bifidobacterium. Numerous scales were used to evaluate cognition, but the mini-mental state examination was the most popular, and the most prevalent impairment was Alzheimer's disease. The supplements with the most significant impact on gut microbiota were vitamin B-12 and folic acid.

Conclusion

This systematic review concluded that vitamins, gut microbiota and antibiotics have a close association with the development of dementia. More research is required to establish causality and elucidate the underlying mechanisms because there is still little evidence connecting the interactions of vitamins, medications, and microbiota with dementia. The complexity of interactions between genetics, lifestyle factors, and comorbidities, as well as the heterogeneity of dementia, may make it more challenging to interpret the findings.

Physiologically based pharmacokinetic (PBPK) modelling of oral drug absorption in older adults - an AGePOP review

The older population consisting of persons aged 65 years or older is the fastest-growing population group and also the major consumer of pharmaceutical products. Due to the heterogenous ageing process, this age group shows high interindividual variability in the dose-exposure-response relationship and, thus, a prediction of drug safety and efficacy is challenging. Although physiologically based pharmacokinetic (PBPK) modelling is a well-established tool to inform and confirm drug dosing strategies during drug development for special population groups, age-related changes in absorption are poorly accounted for in current PBPK models. The purpose of this review is to summarise the current state-of-knowledge in terms of physiological changes with increasing age that can influence the oral absorption of dosage forms. The capacity of common PBPK platforms to incorporate these changes and describe the older population is also discussed, as well as the implications of extrinsic factors such as drug-drug interactions associated with polypharmacy on the model development process. The future potential of this field will rely on addressing the gaps identified in this article, which can subsequently supplement in-vitro and in-vivo data for more robust decision-making on the adequacy of the formulation for use in older adults and inform pharmacotherapy.

Nutrition Strategies Promoting Healthy Aging: From Improvement of Cardiovascular and Brain Health to Prevention of Age-Associated Diseases

BACKGROUND

An increasing number of studies suggest that diet plays an important role in regulating aging processes and modulates the development of the most important age-related diseases.

OBJECTIVE

The aim of this review is to provide an overview of the relationship between nutrition and critical age-associated diseases.

METHODS

A literature review was conducted to survey recent pre-clinical and clinical findings related to the role of nutritional factors in modulation of fundamental cellular and molecular mechanisms of aging and their role in prevention of the genesis of the diseases of aging.

RESULTS

Studies show that the development of cardiovascular and cerebrovascular diseases, neurodegenerative diseases, cognitive impairment and dementia can be slowed down or prevented by certain diets with anti-aging action. The protective effects of diets, at least in part, may be mediated by their beneficial macro- (protein, fat, carbohydrate) and micronutrient (vitamins, minerals) composition.

CONCLUSIONS

Certain diets, such as the Mediterranean diet, may play a significant role in healthy aging by preventing the onset of certain diseases and by improving the aging process itself. This latter can be strengthened by incorporating fasting elements into the diet. As dietary recommendations change with age, this should be taken into consideration as well, when developing a diet tailored to the needs of elderly individuals. Future and ongoing clinical studies on complex anti-aging dietary interventions translating the results of preclinical investigations are expected to lead to novel nutritional guidelines for older adults in the near future.

Validation of FES-I and Short FES-I Scales in the Polish Setting as the Research Tools of Choice to Identify the Fear of Falling in Older Adults

Fear of falling is associated with a clear hazard to individual self-reliance, reduced physical activity, as well as a sense of shame and loss of self-confidence. The present study aimed to complete the applicable translation and validation protocol for the Falls Efficacy Scale-International (FES-I) tool, following its prior adaptation to ensure full compatibility with the Polish setting. The FES-I questionnaire, along with its abridged version, was translated in line with the recommended standards of the MAPI Institute, taking into account both the cultural fabric and pertinent language specifics of the country. The survey was attended by 740 individuals (N = 740; 463 women, 277 men), over 60 years old. All respondents were required to complete both the FES-I and FES-I (Short) questionnaires twice, following an intervening period, and subsequently had their responses statistically assessed. The FES-I questionnaire, along with its abridged version, may be recommended as an effective assessment tool for addressing the fear of falling issue among the older adults, consequently allowing the teams of attending physicians, physiotherapists, psychologists, or psychiatrists to complete an unambiguous diagnosis, with a view to helping the patients overcome this particular type of anxiety.

Sex-specific interventions to prevent and manage frailty

There is growing interest in interventions that delay, slow, and even reverse frailty. In this narrative review, we explore the evidence on exercise, nutrition, medication optimisation and social support interventions for frailty and consider how these relate to underlying frailty pathophysiology. We also consider pathophysiological mechanisms underpinning sex differences in frailty before evaluating the limited evidence for sex-specific frailty interventions that is currently available. Through this review of the literature, we generate a list of potential sex-specific interventions for frailty. While individual-level recommendations are certainly important, future work should turn the focus towards population-level interventions that take into account sex differences in frailty, including changes to healthcare and socioeconomic systems, as well as changes to the built environment to promote healthy behaviours.

Polypharmacy With High Drug Burden Index (DBI) Alters the Gut Microbiome Overriding Aging Effects and Is Reversible With Deprescribing

Aging, medication use, and global function are associated with changes in the microbiome. However, their interrelationships and changes over time require further characterization. In a longitudinal aging mouse study, we investigated the effects of aging, chronic polypharmacy with a high Drug Burden Index (DBI, measure of total anticholinergic and sedative medication exposure) and gradual cessation (deprescribing) on the microbiome, further exploring any association with global outcomes. Chronic administration of high DBI polypharmacy attenuated the aging-related reduction in alpha diversity, which was not sustained after deprescribing. Beta diversity and LEfSe (Linear discriminant analysis Effect Size) features varied with age, polypharmacy, and deprescribing. Aging with and without polypharmacy shared decreases in Bifidobacteriaceae, Paraprevotellaceae, Bacteroidaceae, and Clostridiaceae, while only aging with polypharmacy showed increased LEfSe features. Microbiome diversity correlated with frailty, nesting, and open field performance. Polypharmacy deprescribing reversed changes that occurred with treatment. However, the microbiome did not recover to its pretreatment composition at 12 months, nor develop the same aging-related changes from 12 to 24 months as the control group. Overall, aging, chronic polypharmacy, and deprescribing differentially affected the diversity and composition of the gut microbiome, which is associated with frailty and function.

Sarcopenia in community-dwelling older adults is associated with the diversity and composition of the gut microbiota

Sarcopenia is a prognostic indicator of negative consequences in older adults, including physical disability, frailty, and mortality. Few studies have investigated the associations between sarcopenia and the gut microbiota. We sought such associations in community-dwelling older adults aged ≥60 years. Sarcopenia was defined as low muscle mass, plus reduced physical performance, and/or low skeletal muscle strength. 16S rRNA next-generation sequencing was used to identify the components of the gut microbiota in fecal samples from 27 older adults with sarcopenia and 33 without sarcopenia. Relationships between sarcopenia and the diversity and composition of the gut microbiota were analyzed. Diversities at the species level were detected between the sarcopenia and control groups (P = 0.049). The abundance of Prevotella and Prevotella copri was significantly lower (P = 0.021 and P = 0.018 respectively) and that of Parabacteroides sp. higher in the sarcopenia than the control group (P = 0.010). Linear discriminant analysis of effect size revealed differences in the microbiota composition between the two groups. Sarcopenia was related with the presence of Anaerotruncus and Phascolarctobacterium sp. and the absence of Prevotella sp. and Prevotella copri. Further research is warranted to clarify whether changes in the gut microbiota cause sarcopenia onset or development.

Canine Geriatric Syndrome: A Framework for Advancing Research in Veterinary Geroscience

Biological aging is the single most important risk factor for disease, disability, and ultimately death in geriatric dogs. The effects of aging in companion dogs also impose significant financial and psychological burdens on their human caregivers. The underlying physiologic processes of canine aging may be occult, or early signs of aging may be ignored because of the misconception that biological aging is natural and therefore inevitable. The ability to detect, quantify, and mitigate the deleterious processes of canine aging would greatly enhance veterinary preventative medicine and animal welfare. In this paper we propose a new conceptual framework for aging in dogs, the Canine Geriatric Syndrome (CGS). CGS consists of the multiple, interrelated physical, functional, behavioral, and metabolic changes that characterize canine aging as well as the resulting clinical manifestations, including frailty, diminished quality of life, and age-associated disease. We also identify potential key components of a CGS assessment tool, a clinical instrument that would enable veterinarians to diagnose CGS and would facilitate the development and testing of interventions to prolong healthspan and lifespan in dogs by directly targeting the biological mechanisms of aging. There are many gaps in our knowledge of the mechanisms and phenotype of aging in dogs that must be bridged before a CGS assessment tool can be deployed. The conceptual framework of CGS should facilitate identifying these gaps and should stimulate research to better characterize the processes and effects of aging in dogs and to identify the most promising preventative strategies to target these.

Research progress of gut microbiota and frailty syndrome

Frailty is a clinical syndrome caused by homeostasis imbalance. It is characterized by marked vulnerability to endogenous or exogenous stressors, reduced self-care ability, and increased mortality risk. This aging-related syndrome is common in individuals older than 65 years and carries an increased risk for poor health outcomes. These include falls, incident disability, incapacity, and mortality. In addition, it can result in a poor prognosis for other comorbidities. With the aging population, frailty increases the burden of adverse health outcomes. Studies on frailty are at their infancy. In addition, there is a lack of thorough understanding of its pathogenesis. Several studies have suggested that frailty is caused by chronic inflammation due to enhanced intestinal permeability following gut microbiota imbalance as well as pathogen-related antibodies entering the circulation system. These result in musculoskeletal system disorders and neurodegenerative diseases. However, this assumption has not been validated in large cohort-based studies. Several studies have suggested that inflammation is not the only cause of frailty. Hence, further studies are necessary to extend our understanding of its pathogenesis. This review summarizes the research findings in the field and expands on the possible role of the gut microbiota in frailty syndrome.

Nutrition and Frailty: Opportunities for Prevention and Treatment

Frailty is a syndrome of growing importance given the global ageing population. While frailty is a multifactorial process, poor nutritional status is considered a key contributor to its pathophysiology. As nutrition is a modifiable risk factor for frailty, strategies to prevent and treat frailty should consider dietary change. Observational evidence linking nutrition with frailty appears most robust for dietary quality: for example, dietary patterns such as the Mediterranean diet appear to be protective. In addition, research on specific foods, such as a higher consumption of fruit and vegetables and lower consumption of ultra-processed foods are consistent, with healthier profiles linked to lower frailty risk. Few dietary intervention studies have been conducted to date, although a growing number of trials that combine supplementation with exercise training suggest a multi-domain approach may be more effective. This review is based on an interdisciplinary workshop, held in November 2020, and synthesises current understanding of dietary influences on frailty, focusing on opportunities for prevention and treatment. Longer term prospective studies and well-designed trials are needed to determine the causal effects of nutrition on frailty risk and progression and how dietary change can be used to prevent and/or treat frailty in the future.

New Horizons in the impact of frailty on pharmacokinetics: latest developments

Frail older people have a high prevalence of drug use and are susceptible to adverse drug reactions. The physiological changes of frailty are likely to affect pharmacokinetics and pharmacodynamics. We reviewed the methods and findings of published studies of pharmacokinetics in frailty. Nine studies describing pharmacokinetics and an additional three of pharmacokinetic pathways in frail older people were identified. Most pharmacokinetic studies investigated a single administration of a medication, dose or formulation, in small populations, often with limited representation of males or females, and applied variable definitions of frailty. Pharmacokinetic sampling designs generally utilised saturated sampling followed by analysis based on the trapezoidal rule for area under the curve, with more recent studies using sparser sampling and more sophisticated modelling to obtain individual and population values of all pharmacokinetic parameters. Overall, the pharmacokinetic studies reported only small changes in some parameters for some drugs with frailty, with the most consistent change reduced hepatic clearance in frail older people. Recommendations for future studies of pharmacokinetics in frailty include (i) standard objective definitions of frailty; (ii) larger studies including people with mild, moderate and severe frailty; (iii) population pharmacokinetic modelling to allow sparser sampling and consideration of multiple influences on pharmacokinetics; (iv) physiologically based modelling as the physiology of frailty emerges and (v) longitudinal pharmacokinetic studies of chronic drug therapy from middle to old age and from robust to pre-frail to frail, including pre-clinical studies. These data, accompanied by pharmacodynamics data in frailty, will inform safe, effective prescribing for frail older people.

Evidence for the Contribution of Gut Microbiota to Age-Related Anabolic Resistance

Globally, people 65 years of age and older are the fastest growing segment of the population. Physiological manifestations of the aging process include undesirable changes in body composition, declines in cardiorespiratory fitness, and reductions in skeletal muscle size and function (i.e., sarcopenia) that are independently associated with mortality. Decrements in muscle protein synthetic responses to anabolic stimuli (i.e., anabolic resistance), such as protein feeding or physical activity, are highly characteristic of the aging skeletal muscle phenotype and play a fundamental role in the development of sarcopenia. A more definitive understanding of the mechanisms underlying this age-associated reduction in anabolic responsiveness will help to guide promyogenic and function promoting therapies. Recent studies have provided evidence in support of a bidirectional gut-muscle axis with implications for aging muscle health. This review will examine how age-related changes in gut microbiota composition may impact anabolic response to protein feeding through adverse changes in protein digestion and amino acid absorption, circulating amino acid availability, anabolic hormone production and responsiveness, and intramuscular anabolic signaling. We conclude by reviewing literature describing lifestyle habits suspected to contribute to age-related changes in the microbiome with the goal of identifying evidence-informed strategies to preserve microbial homeostasis, anabolic sensitivity, and skeletal muscle with advancing age.

An exercise intervention alters stool microbiota and metabolites among older, sedentary adults

BACKGROUND

Physiologic aging has been associated with gut dysbiosis. Although short exercise interventions have been linked to beneficial changes in gut microbiota in younger adults, limited data are available from older populations. We hypothesized that exercise would produce beneficial shifts in microbiota and short-chain fatty acid (SCFA) levels in older persons.

METHODS

Stool samples were collected before and at completion of a supervised 24-week cardiovascular and resistance exercise intervention among 50-75-year-old participants. SCFA levels were analyzed by gas chromatography and microbiome by 16S rRNA gene sequencing. Negative binomial regression models compared pre- and post-differences using false discovery rates for multiple comparison.

RESULTS

A total of 22 participants provided pre-intervention samples; 15 provided samples at study completion. At baseline, the majority of participants were men (95%), mean age 58.0 (8.8) years, mean body mass index 27.4 (6.4) kg/m2. After 24 weeks of exercise, at the genus level, exercise was associated with significant increases in Bifidobacterium (and other unidentified genera within Bifidobacteriaceae), Oscillospira, Anaerostipes, and decreased Prevotella and Oribacterium (p < 0.001). Stool butyrate increased with exercise [5.44 (95% confidence interval 1.54, 9.24) mmol/g, p = 0.02], though no significant differences in acetate or propionate (p ⩾ 0.09) were seen.

CONCLUSION

Our pilot study suggested that an exercise intervention is associated with changes in the microbiome of older adults and a key bacterial metabolite, butyrate. Although some of these changes could potentially reverse age-related dysbiosis, future studies are required to determine the contribution of changes to the microbiome in the beneficial effect of exercise on overall health of older adults. Clinical Trials NCT02404792.

The Gut-Muscle Axis in Older Subjects with Low Muscle Mass and Performance: A Proof of Concept Study Exploring Fecal Microbiota Composition and Function with Shotgun Metagenomics Sequencing

The gut microbiota could influence the pathophysiology of age-related sarcopenia through multiple mechanisms implying modulation of chronic inflammation and anabolic resistance. The aim of this study was to compare the fecal microbiota composition and functionality, assessed by shotgun metagenomics sequencing, between two groups of elderly outpatients, differing only for the presence of primary sarcopenia. Five sarcopenic elderly subjects and twelve non-sarcopenic controls, classified according to lower limb function and bioimpedance-derived skeletal muscle index, provided a stool sample, which was analyzed with shotgun metagenomics approaches, to determine the overall microbiota composition, the representation of bacteria at the species level, and the prediction of bacterial genes involved in functional metabolic pathways. Sarcopenic subjects displayed different fecal microbiota compositions at the species level, with significant depletion of two species known for their metabolic capacity of producing short-chain fatty acids (SCFAs), Faecalibacterium prausnitzii and Roseburia inulinivorans, and of Alistipes shahii. Additionally, their fecal metagenome had different representation of genes belonging to 108 metabolic pathways, namely, depletion of genes involved in SCFA synthesis, carotenoid and isoflavone biotransformation, and amino acid interconversion. These results support the hypothesis of an association between microbiota and sarcopenia, indicating novel possible mediators, whose clinical relevance should be investigated in future studies.

The environment as a determinant of successful aging or frailty

The number of elderly persons is rising rapidly, and healthspan is a key factor in determining the well-being of individuals and the sustainability of national health systems. Environmental health is crucial for a "successful aging". Complex relationships between environmental factors and non-communicable diseases play a major role, causing or accelerating disabilities. Besides genetic factors, aging results from the concurrence of several environmental factors starting from early (i.e. in utero) life, able to increase susceptibility to diseases in adulthood, and to promote frailty in the elderly. In aged people, an unhealthy environment contributes to a fast and early decline and increases vulnerability. Exposure to pollutants facilitates the onset and progression of cardiovascular, respiratory, metabolic and neurologic diseases through direct effects and epigenetic mechanisms negatively affecting biological age. Healthy diet, healthy environment and constant physical activity could counteract, at least in part, the negative effects of environmental stressors. Almost all environmental factors generating detrimental effects on aging are modifiable, with relevant implications in terms of primary prevention measures potentially leading to decreased frailty, to an increase in the number of years lived without diseases or disability, and to a significant reduction in health expenditure.

Gut microbiota assessment in Moscow long-livers using next generation sequencing

Demographic aging poses a challenge to the medical community, pressing for research into the biological factors promoting longevity and its features. Below, we look at the gut microbiota as one of such factors. The aim of this non-longitudinal study was to profile the gut microbiota of centenarians and to compare it with that of relatively healthy, younger Moscow residents. The study recruited 20 people aged 97–100 years (mean age 98 ± 1 year); the control group consisted of 92 individuals aged 53 ± 13 years. For each stool sample, the variable V3–V4 regions of the microbial 16S rRNA gene were sequenced. Primary analysis, read filtering and taxonomic identification were conducted in the QIIME 1.9 environment; reconstruction of metabolic pathways was aided by PICRUSt. Statistical analysis was performed by means of Python v. 3.2. A few differences were detected between the gut microbiota of centenarians and younger individuals: Bifidobacterium (p = 0.026) and Coprococcus eutactus (р = 0.026) were more abundant in centenarians, whereas Bacteroides (p = 0.003) and Prevotella (р = 0.002) were better represented in younger participants. The potential for butyric acid synthesis was higher in the group of centenarians (p = 0.048). Surprisingly, the gut microbiota of centenarians was more diverse and surprisingly beneficial for advanced age. Besides, the gut microbiota of centenarians might have more pronounced anti-inflammatory potential due to its ability to better synthesize butyric acid.