Population-based metagenomics analysis reveals altered gut microbiome in sarcopenia: data from the Xiangya Sarcopenia Study

Faecalibacterium prausnitzii regulates carbohydrate metabolic functions of the gut microbiome in C57BL/6 mice

The probiotic impact of microbes on host metabolism and health depends on both host genetics and bacterial genomic variation. Faecalibacterium prausnitzii is the predominant human gut commensal emerging as a next-generation probiotic. Although this bacterium exhibits substantial intraspecies diversity, it is unclear whether genetically distinct F. prausnitzii strains might lead to functional differences in the gut microbiome. Here, we isolated and characterized a novel F. prausnitzii strain (UT1) that belongs to the most prevalent but underappreciated phylogenetic clade in the global human population. Genome analysis showed that this butyrate-producing isolate carries multiple putative mobile genetic elements, a clade-specific defense system, and a range of carbohydrate catabolic enzymes. Multiomic approaches were used to profile the impact of UT1 on the gut microbiome and associated metabolic activity of C57BL/6 mice at homeostasis. Both 16S rRNA and metagenomic sequencing demonstrated that oral administration of UT1 resulted in profound microbial compositional changes including a significant enrichment of Lactobacillus, Bifidobacterium, and Turicibacter. Functional profiling of the fecal metagenomes revealed a markedly higher abundance of carbohydrate-active enzymes (CAZymes) in UT1-gavaged mice. Accordingly, UT1-conditioned microbiota possessed the elevated capability of utilizing starch in vitro and exhibited a lower availability of microbiota-accessible carbohydrates in the gut. Further analysis uncovered a functional network wherein UT1 reduced the abundance of mucin-degrading CAZymes and microbes, which correlated with a concomitant reduction of fecal mucin glycans. Collectively, our results reveal a crucial role of UT1 in facilitating the carbohydrate metabolism of the gut microbiome and expand our understanding of the genetic and phenotypic diversity of F. prausnitzii.

Molecular mechanisms and therapeutic strategies of gut microbiota modulation in Sarcopenia (Review)

Sarcopenia is an age-related disease that is characterized by a decline in muscle mass and function with significant epidemiological and clinical implications. In recent years, gut microbiota has gained attention as an important regulatory factor in human health. To the best of our knowledge, this is the first study to introduce the definition and epidemiological background of sarcopenia and analyze the potential impact of the gut microbiota on muscle metabolism and growth, including aspects such as gut microbiota metabolites, muscle protein synthesis and energy metabolism. Additionally, this article summarizes the current research progress in gut microbiota interventions for the treatment of sarcopenia, such as probiotics, prebiotics and fecal microbiota transplantation and discusses future research directions and potential therapeutic strategies.

From Clinical to Benchside: Lacticaseibacillus and Faecalibacterium Are Positively Associated With Muscle Health and Alleviate Age-Related Muscle Disorder

Sarcopenia is an age-related muscle disorder that increases risks of adverse clinical outcomes, but its treatments are still limited. Gut microbiota is potentially associated with sarcopenia, and its role is still unclear. To investigate the role of gut microbiota in sarcopenia, we first compared gut microbiota and metabolites composition in old participants with or without sarcopenia. Fecal microbiota transplantation (FMT) from human donors to antibiotic-treated recipient mice was then performed. Specific probiotics and their mechanisms to treat aged mice were identified. Old people with sarcopenia had different microbial composition and metabolites, including Paraprevotella, Lachnospira, short-chain fatty acids, and purine. After FMT, mice receiving microbes from people with sarcopenia displayed lower muscle mass and strength compared with those receiving microbes from non-sarcopenic donors. Lacticaseibacillus rhamnosus (LR) and Faecalibacterium prausnitzii (FP) were positively related to muscle health of old people, and enhanced muscle mass and function of aged mice. Transcriptomics showed that genes related to tricarboxylic acid cycle (TCA) were enriched after treatments. Metabolic analysis showed increased substrates of TCA cycle in both LR and FP supernatants. Muscle mitochondria density, ATP content, NAD+/NADH, mitochondrial dynamics and biogenesis proteins, as well as colon tight junction proteins of aged mice were improved by both probiotics. LR and the combination of two probiotics also benefit intestinal immune health by reducing CD8+ IFNγ+ T cells. Gut microbiota dysbiosis is a pathogenesis of sarcopenia, and muscle-related probiotics could alleviate age-related muscle disorders mainly through mitochondria improvement. Further clinical translation is warranted.

Sarcopenia and the biological determinants of aging: A narrative review from a geroscience perspective

BACKGROUND

The physiopathology of sarcopenia shares common biological cascades with the aging process, as does any other age-related condition. However, our understanding of the interconnected pathways between diagnosed sarcopenia and aging remains limited, lacking sufficient scientific evidence.

METHODS

This narrative review aims to gather and describe the current evidence on the relationship between biological aging determinants, commonly referred to as the hallmarks of aging, and diagnosed sarcopenia in humans.

RESULTS

Among the twelve hallmarks of aging studied, there appears to be a substantial association between sarcopenia and mitochondrial dysfunction, epigenetic alterations, deregulated nutrient sensing, and altered intercellular communication. Although limited, preliminary evidence suggests a promising association between sarcopenia and genomic instability or stem cell exhaustion.

DISCUSSION

Overall, an imbalance in energy regulation, characterized by impaired mitochondrial energy production and alterations in circulatory markers, is commonly associated with sarcopenia and may reflect the interplay between aging physiology and sarcopenia biology.

The Relationship Between Gut Microbiota, Muscle Mass and Physical Function in Older Individuals: A Systematic Review

BACKGROUND

Recent evidence suggests that sarcopenia and subsequent changes in muscle mass and functional outcomes are linked to disruption to the gastrointestinal microbiota composition and/or function via the microbiota-gut-muscle axis. Despite growing interest, few studies have systemically analysed (1) the relationship between the gut microbiota, muscle mass and physical performance and (2) the effects of gut-modulating dietary interventions on these outcomes within older individuals with or without sarcopenia.

METHODS

Four electronic databases (PubMed, MEDLINE, Embase and Scopus) were searched for articles published from the year 2004 until July 2023. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) were followed. Revised Cochrane Risk of Bias (RoB 2.0) and Joanna Briggs Institute (JBI) critical appraisal checklist were utilised to evaluate the risk of bias within intervention and observational studies, respectively.

RESULTS

A total of 20 studies (14 observational and 6 interventional) involving 4071 older participants (mean age 69.9 years, 51.6% female) were included. There was significant heterogeneity regarding interventions and outcome measures used in these studies. Correlations between microbiota diversity and composition and sarcopenia-related functional outcomes were observed. Interventional studies targeting the gut microbiota resulted in improved muscle strength, body composition or physical function in some, but not all, studies.

CONCLUSIONS

Despite limitations in the studies reviewed, the findings provide further evidence that the development of sarcopenia is likely influenced by an altered gut microbial environment and that interventions targeting the microbiome could hold therapeutic potential for the treatment or management of sarcopenia.

Bifidobacterium animalis Probio-M8 improves sarcopenia physical performance by mitigating creatine restrictions imposed by microbial metabolites

Sarcopenia is a major health challenge due to an aging population. Probiotics may improve muscle function through gut-muscle axis, but their efficacy and mechanisms in treating sarcopenia remain unclear. This study investigated the impact of Bifidobacterium animalis subsp. lactis Probio-M8 (Probio-M8) on old mice and sarcopenia patients. We analyzed 43 subjects, including gut microbiome, fecal metabolome, and serum metabolome, using a multi-omics approach to assess whether Probio-M8 can improve sarcopenia by modulating gut microbial metabolites. Probio-M8 significantly improved muscle function in aged mice and enhanced physical performance in sarcopenia patients. It reduced pathogenic gut species and increased beneficial metabolites such as indole-3-lactic acid, acetoacetic acid, and creatine. Mediating effect analyses revealed that Probio-M8 effectively reduced n-dodecanoyl-L-homoserine lactone level in gut concurrent with increased creatine circulation, to significantly enhance host physical properties. These findings provide new insights into probiotics as a potential treatment for sarcopenia by modulating gut microbiota metabolism.

Associations between gut microbiota and sarcopenia or its defining parameters in older adults: A systematic review

Altered gut microbiota (GM) potentially contribute to development or worsening of sarcopenia through a gut-muscle axis. This systematic review aims to compare GM between persons with sarcopenia or low sarcopenia-defining parameters (muscle mass, strength, and physical performance) to those with preserved muscle status, as well as to clarify possible associations between sarcopenia (-defining parameters) and relative abundance (RA) of GM-taxa or GM-(α- or β) diversity indices, in order to clarify whether there is robust evidence of the existence of a GM signature for sarcopenia. This systematic review was conducted according to the PRISMA-reporting guideline and pre-registered on PROSPERO (CRD42021259597). PubMed, Web of Science, Embase, ClinicalTrials.gov, and Cochrane library were searched until 20 July 2023. Included studies reported on GM and sarcopenia or its defining parameters. Observational studies were included with populations of mean age ≥50 years. Thirty-two studies totalling 10 781 persons (58.56% ♀) were included. Thirteen studies defined sarcopenia as a construct. Nineteen studies reported at least one sarcopenia-defining parameter (muscle mass, strength or physical performance). Studies found different GM-taxa at multiple levels to be significantly associated with sarcopenia (n = 4/6), muscle mass (n = 13/14), strength (n = 7/9), and physical performance (n = 3/3); however, directions of associations were heterogeneous and also conflicting for specific GM-taxa. Regarding β-diversity, studies found GM of persons with sarcopenia, low muscle mass, or low strength to cluster differently compared with persons with preserved muscle status. α-diversity was low in persons with sarcopenia or low muscle mass as compared with those with preserved muscle status, indicating low richness and diversity. In line with this, α-diversity was significantly and positively associated with muscle mass (n = 3/4) and muscle strength (n = 2/3). All reported results were significant (P < 0.05). Persons with sarcopenia and low muscle parameters have less rich and diverse GM and can be separated from persons with preserved muscle mass and function based on GM-composition. Sarcopenia and low muscle parameters are also associated with different GM-taxa at multiple levels, but results were heterogeneous and no causal conclusions could be made due to the cross-sectional design of the studies. This emphasizes the need for uniformly designed cross-sectional and longitudinal trials with appropriate GM confounder control in large samples of persons with sarcopenia and clearly defined core outcome sets in order to further explore changes in GM-taxa and to determine a sarcopenia-specific GM-signature.

The gut microbiome, chronic kidney disease, and sarcopenia

Sarcopenia is a prevalent condition in patients with chronic kidney disease (CKD), intricately linked to adverse prognoses, heightened cardiovascular risks, and increased mortality rates. Extensive studies have found a close and complex association between gut microbiota, kidney and muscle. On one front, patients with CKD manifest disturbances in gut microbiota and alterations in serum metabolites. These abnormal microbiota composition and metabolites in turn participate in the development of CKD. On another front, altered gut microbiota and its metabolites may lead to significant changes in metabolic homeostasis and inflammation, ultimately contributing to the onset of sarcopenia. The disturbance of gut microbial homeostasis, coupled with the accumulation of toxic metabolites, exerts deleterious effects on skeletal muscles in CKD patients with sarcopenia. This review meticulously describes the alterations observed in gut microbiota and its serum metabolites in CKD and sarcopenia patients, providing a comprehensive overview of pertinent studies. By delving into the intricate interplay of gut microbiota and serum metabolites in CKD-associated sarcopenia, we aim to unveil novel treatment strategies for ameliorating their symptoms and prognosis.

Exploring the Relationship Between Gut Microbiota and Sarcopenia Based on Gut-Muscle Axis

Sarcopenia, as a disease characterized by progressive decline of quality, strength, and function of muscles, has posed an increasingly significant threat to the health of middle-aged and elderly individuals in recent years. With the continuous deepening of studies, the concept of gut-muscle axis has attracted widespread attention worldwide, and the occurrence and development of sarcopenia are believed to be closely related to the composition and functional alterations of gut microbiota. In this review, combined with existing literatures and clinical reports, we have summarized the role and impacts of gut microbiota on the muscle, the relevance between gut microbiota and sarcopenia, potential mechanisms of gut microbiota in the modulation of sarcopenia, potential methods to alleviate sarcopenia by modulating gut microbiota, and relevant advances and perspectives, thus contributing to adding more novel knowledge to this research direction and providing certain reference for future related studies.

Metagenomic Sequencing Elucidated the Microbial Diversity of Rearing Water Environments for Sichuan Taimen (Hucho bleekeri)

BACKGROUND

Sichuan taimen (Hucho bleekeri) is a fish species endemic to China's upper Yangtze River drainage and has significant value as an aquatic resource. It was listed as a first-class state-protected wild animal by the Chinese government due to its very limited distribution and wild population at present.

METHODS

To elucidate the diversity of microorganisms in rearing water environments for H. bleekeri, metagenomic sequencing was applied to water samples from the Maerkang and Jiguanshan fish farms, where H. bleekeri were reared.

RESULTS

The results revealed that Pseudomonadota was the dominant phylum in the microbial communities of the water samples. Among the shared bacterial groups, Cyanobacteriota, Actinomycetota, Planctomycetota, Nitrospirota, and Verrucomicrobiota were significantly enriched in the water environment of Jiguanshan (p < 0.01), while Bacteroidota was more enriched in that of Maerkang (p < 0.01). Additionally, the Shannon diversity and Simpson index of the microbial community in the water environment of Maerkang were lower than in that of Jiguanshan.

CONCLUSIONS

The present study demonstrated the similarities and differences in the microbial compositions of rearing water environments for H. bleekeri, which are expected to benefit the artificial breeding of H. bleekeri in the future.

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.

Serum metabolomics analysis of malnutrition in patients with gastric cancer: a cross sectional study

BACKGROUND

Although malnutrition is common in cancer patients, its molecular mechanisms has not been fully clarified. This study aims to identify significantly differential metabolites, match the corresponding metabolic pathways, and develop a predictive model of malnutrition in patients with gastric cancer.

METHODS

In this cross-sectional study, we applied non-targeted metabolomics using liquid chromatography-mass spectrometry to explore the serum fingerprinting of malnutrition in patients with gastric cancer. Malnutrition-specific differential metabolites were identified by orthogonal partial least-squares discriminant analysis and t-test and matched with the Human Metabolome Database and the LIPID Metabolites and Pathways Strategy. We matched the corresponding metabolic pathways of malnutrition using pathway analysis at the MetaboAnalyst 5.0. We used random forest analyses to establish the predictive model.

RESULTS

We recruited 220 malnourished and 198 non-malnourished patients with gastric cancer. The intensities of 25 annotated significantly differential metabolites were lower in patients with malnutrition than those without, while two others were higher in patients with malnutrition than those without, including newly identified significantly differential metabolites such as indoleacrylic acid and lysophosphatidylcholine(18:3/0:0). We matched eight metabolic pathways associated with malnutrition, including aminoacyl-tRNA biosynthesis, tryptophan metabolism, and glycerophospholipid metabolism. We established a predictive model with an area under the curve of 0.702 (95% CI: 0.651-0.768) based on four annotated significantly differential metabolites, namely indoleacrylic acid, lysophosphatidylcholine(18:3/0:0), L-tryptophan, and lysophosphatidylcholine(20:3/0:0).

CONCLUSIONS

We identified 27 specific differential metabolites of malnutrition in malnourished compared to non-malnourished patients with gastric cancer. We also matched eight corresponding metabolic pathways and developed a predictive model. These findings provide supportive data to better understand molecular mechanisms of malnutrition in patients with gastric cancer and new strategies for the prediction, diagnosis, prevention, and treatment for those malnourished.

Association of Gut Microbiome with Muscle Mass, Muscle Strength, and Muscle Performance in Older Adults: A Systematic Review

Sarcopenia, characterized by reduced muscle mass, strength, or performance, is a common condition in older adults. The association between the gut microbiome and sarcopenia remains poorly understood. This systematic review aims to evaluate the relationship between muscle parameters and the intestinal microbiome. A systematic search was conducted in PubMed, EMBASE, Cochrane Library, and Google Scholar for studies published between 2002 and 2022 involving participants aged 50+. Studies were included if they assessed sarcopenia using at least one measure of muscle mass (skeletal muscle mass, bioelectrical impedance analysis, MRI), muscle strength, or muscle performance (SARC-F questionnaire, Timed-Up-and-Go Test, Chair Stand Test, grip strength, gait speed, Short Physical Performance Battery, 400 m Walk Test). The microbiome was measured using at least RNA/DNA sequencing or shotgun metagenomic sequencing. Twelve studies were analyzed. Findings revealed that a higher abundance of bacterial species such as Desulfovibrio piger, and Clostridium symbiosum and reduced diversity of butyrate-producing bacteria was associated with sarcopenia severity, as indicated by decreased grip strength, muscle mass, or physical performance. The gut microbiome plays a significant role in age-related muscle loss. Probiotics, prebiotics, and bacterial products could be potential interventions to improve muscle health in older adults.

Gut microbial features and circulating metabolomic signatures of frailty in older adults

Frailty, a multidimensional indicator of suboptimal aging, reflects cumulative declines across multiple physiological systems. Although age-related changes have been reported in gut microbiota, their role in healthy aging remains unclear. In this study, we calculated frailty index (FI) from 33 health-related items to reflect the overall health status of 1,821 older adults (62-96 years, 55% female) and conducted multi-omics analysis using gut metagenomic sequencing data and plasma metabolomic data. We identified 18 microbial species and 17 metabolites shifted along with frailty severity, with stronger links observed in females. The associations of nine species, including various Clostridium species and Faecalibacterium prausnitzii, with FI were reproducible in two external populations. Plasma glycerol levels, white blood cell count and kidney function partially mediated these associations. A composite microbial score derived from FI significantly predicted 2-year mortality (adjusted hazard ratio across extreme quartiles, 2.86; 95% confidence interval, 1.38-5.93), highlighting the potential of microbiota-based strategies for risk stratification in older adults.

Causal Relationship Between Gut Microbiota, Metabolites, and Sarcopenia: A Mendelian Randomization Study

BACKGROUND

Gut microbiota imbalance and sarcopenia are frequently observed in older adults. Gut microbiota and their metabolites are considered risk factors contributing to the heightened risk of sarcopenia, but whether these associations are causal remains unclear.

METHODS

We conducted linkage disequilibrium score regression and 2-sample Mendelian randomization (MR) methods with single-nucleotide polymorphisms sourced from large-scale genome-wide association studies as instrumental variables to examine the causal associations linking gut microbiota with their metabolites to the sarcopenia. Following the MR analysis, subsequent sensitivity analyses were conducted to reinforce the robustness and credibility of the obtained results.

RESULTS

MR analysis yielded compelling evidence demonstrating the correlation between genetically predicted gut microbiota and metabolites and the risk of sarcopenia. The abundance of Porphyromonadaceae, Rikenellaceae, Terrisporobacter, and Victivallis was found to be associated with walking pace. Our study also found suggestive associations of 12 intestinal bacteria with appendicular lean mass, and of Streptococcaceae, Intestinibacter, Paraprevotella, Ruminococcaceae UCG009, and Sutterella with grip strength. Specifically, we identified 21 gut microbiota-derived metabolites that may be associated with the risk of sarcopenia.

CONCLUSIONS

Utilizing a 2-sample MR approach, our study elucidates the causal interplay among gut microbiota, gut microbiota-derived metabolites, and the occurrence of sarcopenia. These findings suggest that gut microbiota and metabolites may represent a potential underlying risk factor for sarcopenia, and offer the promise of novel therapeutic focal points.

Assessment of the potential risks in SD rats gavaged with genetically modified yeast containing the cp4-epsps gene

Introduction

Despite the absence of definitive evidence indicating that the cp4-epsps gene and its resultant recombinant proteins have significant harmful effects on either human or animal health, the safety assessment of genetically modified (GM) crops expressing the CP4-EPSPS proteins has been controversial. This study endeavor was aimed at evaluating the potential risks posed by the CP4-EPSPS protein in transgenic crops, thereby contributing to the advancement of risk assessment methodologies in the context of genetically engineered crops.

Methods

To ascertain the appropriate daily dosages for oral gavage administration, the expression levels of the CP4-EPSPS protein in a recombinant yeast were quantified. Subsequently, physiological and biochemical analysis, metabolomics, and metagenomic analysis were conducted based on a 90-day Sprague-Dawley (SD) rats feeding experiment, respectively, thereby enhancing the depth and precision of our risk assessment framework.

Results

The results from the physiological and biochemical analysis, organ pathological, blood metabolism, gut microbiota, and correlation analysis of metabolites and gut microbiota revealed several biomarkers for further risk assessment. These biomarkers include clinical biochemical indexes such as total bilirubin (TBIL), direct bilirubin (DBIL), creatine kinase (CK), and lactate dehydrogenase (LDH); metabolites like Methionine, 2-Oxovaleric acid, and LysoPC (16:0); and gut microbiota including Blautia wexlerae, Holdemanella biformis, Dorea sp. CAG 317, Coriobacteriaceae and Erysipelotrichaceae.

Conclusion

In conclusion, the risk can be significantly reduced by directly consuming inactivated recombinant CP4-EPSPS. Therefore, in everyday life, the risk associated with consuming GM foods containing recombinant CP4-EPSPS is substantially reduced after heat treatment.

Gut microbial composition is altered in sarcopenia: A systematic review and meta-analysis of clinical studies

Increasing evidence has shown that gut microbiota (GM) was involved in the pathophysiology of musculoskeletal disorders through multiple pathways such as protein anabolism, chronic inflammation and immunity, and imbalanced metabolism. We performed a systematic review and meta-analysis of human studies to evaluate GM diversity differences between individuals with and without sarcopenia, and explore bacteria with potential to become biomarkers. PubMed, Embase and Cochrane library were systematically searched from inception to February 16, 2024. Studies were included if they (1) sampled adults with sarcopenia, and (2) performed GM analysis and reported α-diversity, β-diversity or relative abundance. The methodological quality of included studies and the certainty of evidence were assessed through the Joanna Briggs Institute critical appraisal checklist for analytical cross-sectional studies and the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) Working Group system, respectively. Weighted standardized mean differences (SMDs) and corresponding 95% confidence intervals (CIs) were estimated for α-diversity indices using a fixed-effects and a random-effects model. Beta diversity and the relative abundance of GM were summarized qualitatively. A total of 19 studies involving 6,565 participants were included in this study. Compared with controls, significantly moderate decrease in microbial richness in participants with sarcopenia were found (Chao1: SMD = -0.44; 95%CI, -0.64 to -0.23, I2 = 57.23%, 13 studies; observed species: SMD = -0.68; 95%CI, -1.00 to -0.37, I2 = 66.07%, 5 studies; ACE index: SMD = -0.30; 95%CI, -0.56 to -0.04, I2 = 8.12%, 4 studies), with very low certainty of evidence. Differences in β-diversity were consistently observed in 84.6% of studies and 97.3% of participants. The detailed analysis of the gut microbial differential abundance identified a loss of Prevotellaceae, Prevotella, and Megamonas in sarcopenia compared with non-sarcopenia. In conclusion, sarcopenia was found to be associated with reduced richness of GM, and supplementing intestinal bacteria described above may contribute to preventing and treating this muscle disease. The research protocol was registered and approved in PROSPERO (CRD42023412849).

Health effect of multiple air pollutant mixture on sarcopenia among middle-aged and older adults in China

BACKGROUND

As the global aging process accelerates, the health challenges posed by sarcopenia among middle-aged and older adults are becoming increasingly prominent. However, the available evidence on the adverse effects of air pollution on sarcopenia is limited, particularly in the Western Pacific region. This study aimed to explore relationships of multiple air pollutants with sarcopenia and related biomarkers using the nationally representative database.

METHODS

Totally, 6585 participants aged over 45 years were enrolled from the China Health and Retirement Longitudinal Study (CHARLS) in 2011 and 3443 of them were followed up until 2015. Air pollutants were estimated from high-resolution satellite-based spatial-temporal models. In the cross-sectional analysis, we used generalized linear regression, unconditional logistic regression analytical and restricted cubic spline (RCS) methods to assess the single-exposure and non-linear effects of multiple air pollutants on sarcopenia and related surrogate biomarkers (serum creatinine and cystatin C). Several popular mixture analysis techniques such as Bayesian kernel machine regression (BKMR), weighted quantile sum (WQS) regression, and quantile-based g-computation (Qgcomp) were further used to examinate the combined effects of multiple air pollutants. Logistic regression was used to further analyze the longitudinal association between air pollution and sarcopenia.

RESULTS

Each interquartile range increase in PM2.5, PM10 and NO2 was significantly associated with an increased risk of sarcopenia, with adjusted odds ratios (aORs) of 1.09 [95 % confidence interval (CI): 1.01, 1.20], 1.24 (95 % CI: 1.14, 1.35) and 1.18 (95 % CI: 1.08, 1.28), respectively. Our findings also showed that five air pollutants were significantly associated with the sarcopenia index. In addition, employing a mixture analysis approach, we confirmed significant combined effects of air pollution mixtures on sarcopenia risk and associated biomarkers, with PM10 and PM2.5 identified as major contributors to the combined effect. The results of the exposure-response (E-R) relationships, subgroup analysis, longitudinal analysis and sensitivity analysis all showed the unfavorable impact of air pollution on sarcopenia risk and related vulnerable populations.

CONCLUSIONS

Single-exposure and co-exposure to multiple air pollutants were positively associated with sarcopenia among middle-aged and older adults in China. Our study provided new evidence that air pollution mixture was significantly associated with sarcopenia related biomarkers.

Urban-rural differences in the prevalence and associated factors of sarcopenia: A systematic review and meta-analysis

BACKGROUND

Loss of muscle mass, muscle strength, and/or physical performance due to aging is known as sarcopenia. Regardless of how serious this illness is, no single diagnostic criteria have been established. Much research conducted recently has demonstrated differences between built environment characteristics (i.e., urban and rural) and the occurrence of sarcopenia; however, variations in sarcopenia prevalence in urban-rural areas around the world have been reported by fewer studies. This work sought to determine how sarcopenia prevalence varied between urban and rural areas and to explore the associated influencing factors.

METHODS

Using the pertinent MESH phrases and free words, PubMed, Web of Science, Embase, and China national knowledge infrastructure databases were scanned for core sarcopenia literature up to February 26, 2023. Observational studies involving urban-rural patients with sarcopenia published in Chinese and English, and assessing muscle mass via computed tomography, bioelectrical impedance, or dual-energy X-ray absorption techniques were considered as inclusion criteria. The meta-analysis involved analysis of the urban-rural prevalence in subgroups by diagnostic criteria, tools for assessing muscle mass and study type, as well as the factors related to urban-rural differences in the occurrence of sarcopenia. STATA version 11.0 was used to perform the statistical analysis.

RESULTS

Sixty-six articles involving 433,091 participants were included for analysis: of which 27 were analyzed for both prevalence and related factors whereas 39 were for only prevalence. The meta-analysis revealed the prevalence of sarcopenia to be 0.18 (95 % CI 0.14-0.22), with significant heterogeneity (P < 0.001; I2 = 99.9 %). Moreover, the prevalence of sarcopenia in urban group [0.16 (I2 = 99.9 %, 95 % CI 0.1-0.22)] was lower than in rural group [0.2 (I2 = 99.6 %, 95 % CI 0.16-0.25)] and urban-rural group [0.21 (I2 = 97.5 %, 95 % CI 0.16-0.25)]. Besides, the factors significantly associated with sarcopenia in urban-rural areas were age, gender, BMI, malnutrition, physical activity, and polypharmacy. There was significant heterogeneity between these factors and the association of sarcopenia.

CONCLUSIONS

Sarcopenia is associated with aspects of the built environment, and studies have revealed that sarcopenia is more common in rural than in urban populations with influencing factors including age, gender, BMI, poor nutrition, insufficient physical activity, and polypharmacy. The lack of uniform diagnostic criteria makes a robust and comprehensive assessment difficult. Therefore, the formation of certain universal and standardized diagnostic criteria will help future research on sarcopenia.

Gut microbiota and physical activity level: characterization from sedentary to soccer players

Evidence of the relationship between physical activity and gut microbiota composition is steadily increasing. The purpose of the study is to compare the gut microbiota composition of a group of elite male soccer players with a group of subjects with different physical activity levels. Cross-sectional studies were performed on 91 healthy young males, in detail: 17 elite soccer players (23.7 ± 4.2 yrs, BMI 23.2 ± 1.2 kg/m2); 14 with high levels of physical training (24.5 ± 5.6 yrs, BMI 22.7 ± 0.8 kg/m2); 23 with moderate levels of physical training (29.3 ± 3.9 yrs, BMI 22.5 ± 0.8 kg/m2); and 37 healthy men without exercise habits (28.1 ± 5.9 yrs, BMI 22.4 ± 1.0 kg/m2). Relative microbiota composition was determined by analyzing DNA extracted from stool samples. The quality and quantity of extracted DNA were assessed using a Qubit Fluorometer. Differences between subjects' populations were analyzed using a one-way ANOVA, and Bonferroni's post-hoc test was employed to identify localized effects. Elite soccer players and subjects with high physical activity levels showed a significantly higher prevalence of the nine microbiota populations analyzed than subjects with moderate physical training or who were sedentary. No differences were found in the Firmicutes to Bacteroidetes ratio among the different study populations. This study reports the gut microbiota parameters of elite footballers for the first time. In addition, it brings new insights into the effects of different levels of physical activity on the composition of the gut microbiota.

Changes in the gut microbiota of patients with sarcopenia based on 16S rRNA gene sequencing: a systematic review and meta-analysis

Introduction

Sarcopenia, an age-related disease, has become a major public health concern, threatening muscle health and daily functioning in older adults around the world. Changes in the gut microbiota can affect skeletal muscle metabolism, but the exact association is unclear. The richness of gut microbiota refers to the number of different species in a sample, while diversity not only considers the number of species but also the evenness of their abundances. Alpha diversity is a comprehensive metric that measures both the number of different species (richness) and the evenness of their abundances, thereby providing a thorough understanding of the species composition and structure of a community.

Methods

This meta-analysis explored the differences in intestinal microbiota diversity and richness between populations with sarcopenia and non-sarcopenia based on 16 s rRNA gene sequencing and identified new targets for the prevention and treatment of sarcopenia. PubMed, Embase, Web of Science, and Google Scholar databases were searched for cross-sectional studies on the differences in gut microbiota between sarcopenia and non-sarcopenia published from 1995 to September 2023 scale and funnel plot analysis assessed the risk of bias, and performed a meta-analysis with State v.15. 1.

Results

A total of 17 randomized controlled studies were included, involving 4,307 participants aged 43 to 87 years. The alpha diversity of intestinal flora in the sarcopenia group was significantly reduced compared to the non-sarcopenia group: At the richness level, the proportion of Actinobacteria and Fusobacteria decreased, although there was no significant change in other phyla. At the genus level, the abundance of f-Ruminococcaceae; g-Faecalibacterium, g-Prevotella, Lachnoclostridium, and other genera decreased, whereas the abundance of g-Bacteroides, Parabacteroides, and Shigella increased.

Discussion

This study showed that the richness of the gut microbiota decreased with age in patients with sarcopenia. Furthermore, the relative abundance of different microbiota changed related to age, comorbidity, participation in protein metabolism, and other factors. 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/display_record.php?RecordID=475887, CRD475887.

Nexus Between Sarcopenia and Microbiome Research: A Bibliometric Exploration

Despite over 30 years of microbiome and skeletal muscle research, no quantitative analysis of sarcopenia and the microbiome literature had been conducted. Our bibliometric study examined research status, hotspots, and future trends. We utilized bibliometric techniques to search the Science Citation Index Extended Database on February 27, 2023, using the Bibliometrix package in R to create a map displaying scientific production and subject categories. Collaborative network maps between countries/regions were visualized using Scimago Graphica, while VOSviewer explored collaboration modes among individuals and institutions. We analyzed the top 25 emerging keywords, top co-occurring keyword networks, and co-occurring keyword clusters using CiteSpace. A total of 997 articles were retrieved for sarcopenia and microbiome, of which 633 papers were analyzed. Both the number of publications and total citation frequency had been continuously increasing. The United States had the highest total citation frequency, while China had the highest number of publications. Research on the impact of the microbiome on sarcopenia was in its nascent stage and spans multiple disciplines, including nutrition, microbiology, geriatrics, immunology, endocrinology and metabolism, molecular biology, and sports medicine. The University of Copenhagen contributed the most to the number of publications (n=16), with Tibbett M (n=7) and Hulver MW (n=7) among the top authors. The most published journal was "Nutrients" (n=24). Analysis of keywords and clusters revealed new research hotspots in microbes and sarcopenia, such as malnutrition, dietary fiber, signaling pathways, frailty, and intestinal permeability. Research on the impact of the microbiome on sarcopenia is in its infancy and spans multiple disciplines. Malnutrition, dietary fiber, signaling pathways, frailty, and intestinal microbes are currently research hotspots. Furthermore, the visual atlas analysis of research on microbes and sarcopenia helps to track the knowledge structure in research fields related to sarcopenia and microbes, providing direction for future research.

Gut microbiota disturbances in hospitalized older adults with malnutrition and clinical outcomes

OBJECTIVE

Malnutrition is one of the most threatening conditions in geriatric populations. The gut microbiota has an important role in the host's metabolic and muscular health: however, its interplay with disease-related malnutrition is not well understood. We aimed to identify the association of malnutrition with the gut microbiota and predict clinical outcomes in hospitalized acutely ill older adults.

METHODS

We performed a secondary longitudinal analysis in 108 geriatric patients from a prospective cohort evaluated at admission and 72 h of hospitalization. We collected clinical, demographic, nutritional, and 16S rRNA gene-sequenced gut microbiota data. Microbiota diversity, overall composition, and differential abundance were calculated and compared between patients with and without malnutrition. Microbiota features associated with malnutrition were used to predict clinical outcomes.

RESULTS

Patients with malnutrition (51%) had a different microbiota composition compared to those who were well-nourished during hospitalization (ANOSIM R = 0.079, P = 0.003). Patients with severe malnutrition showed poorer α-diversity at admission (Shannon P = 0.012, Simpson P = 0.018) and follow-up (Shannon P = 0.023, Chao1 P = 0.008). Differential abundance of Lachnospiraceae NK4A136 group, Subdoligranulum, and Faecalibacterium prausnitzii were significantly lower and inversely associated with malnutrition, while Corynebacterium, Ruminococcaceae Incertae Sedis, and Fusobacterium were significantly increased and positively associated with malnutrition. Corynebacterium, Ruminococcaceae Incertae Sedis, and the overall composition were important predictors of critical care in patients with malnutrition during hospitalization.

CONCLUSION

Older adults with malnutrition, especially in a severe stage, may be subject to substantial gut microbial disturbances during hospitalization. The gut microbiota profile of patients with malnutrition might help us to predict worse clinical outcomes.

To analyze the relationship between gut microbiota, metabolites and migraine: a two-sample Mendelian randomization study

Background

It has been suggested in several observational studies that migraines are associated with the gut microbiota. It remains unclear, however, how the gut microbiota and migraines are causally related.

Methods

We performed a bidirectional two-sample mendelian randomization study. Genome-wide association study (GWAS) summary statistics for the gut microbiota were obtained from the MiBioGen consortium (n = 18,340) and the Dutch Microbiota Project (n = 7,738). Pooled GWAS data for plasma metabolites were obtained from four different human metabolomics studies. GWAS summary data for migraine (cases = 48,975; controls = 450,381) were sourced from the International Headache Genetics Consortium. We used inverse-variance weighting as the primary analysis. Multiple sensitivity analyses were performed to ensure the robustness of the estimated results. We also conducted reverse mendelian randomization when a causal relationship between exposure and migraine was found.

Results

LachnospiraceaeUCG001 (OR = 1.12, 95% CI: 1.05-1.20) was a risk factor for migraine. Blautia (OR = 0.93, 95% CI: 0.88-0.99), Eubacterium (nodatum group; OR = 0.94, 95% CI: 0.90-0.98), and Bacteroides fragilis (OR = 0.97, 95% CI: 0.94-1.00) may have a suggestive association with a lower migraine risk. Functional pathways of methionine synthesis (OR = 0.89, 95% CI: 0.83-0.95) associated with microbiota abundance and plasma hydrocinnamate (OR = 0.85, 95% CI: 0.73-1.00), which are downstream metabolites of Blautia and Bacteroides fragilis, respectively, may also be associated with lower migraine risk. No causal association between migraine and the gut microbiota or metabolites was found in reverse mendelian randomization analysis. Both significant horizontal pleiotropy and significant heterogeneity were not clearly identified.

Conclusion

This Mendelian randomization analysis showed that LachnospiraceaeUCG001 was associated with an increased risk of migraine, while some bacteria in the gut microbiota may reduce migraine risk. These findings provide a reference for a deeper comprehension of the role of the gut-brain axis in migraine as well as possible targets for treatment interventions.

From gut to liver: unveiling the differences of intestinal microbiota in NAFL and NASH patients

Non-alcoholic fatty liver disease (NAFLD) is increasingly recognized for its global prevalence and potential progression to more severe liver diseases such as non-alcoholic steatohepatitis (NASH). The gut microbiota plays a pivotal role in the pathogenesis of NAFLD, yet the detailed characteristics and ecological alterations of gut microbial communities during the progression from non-alcoholic fatty liver (NAFL) to NASH remain poorly understood. Methods: In this study, we conducted a comparative analysis of gut microbiota composition in individuals with NAFL and NASH to elucidate differences and characteristics. We utilized 16S rRNA sequencing to compare the intestinal gut microbiota among a healthy control group (65 cases), NAFL group (64 cases), and NASH group (53 cases). Random forest machine learning and database validation methods were employed to analyze the data. Results: Our findings indicate a significant decrease in the diversity of intestinal flora during the progression of NAFLD (p < 0.05). At the phylum level, high abundances of Bacteroidetes and Fusobacteria were observed in both NAFL and NASH patients, whereas Firmicutes were less abundant. At the genus level, a significant decrease in Prevotella expression was seen in the NAFL group (AUC 0.738), whereas an increase in the combination of Megamonas and Fusobacterium was noted in the NASH group (AUC 0.769). Furthermore, KEGG pathway analysis highlighted significant disturbances in various types of glucose metabolism pathways in the NASH group compared to the NAFL group, as well as notably compromised flavonoid and flavonol biosynthesis functions. The study uncovers distinct microbiota characteristics and microecological changes within the gut during the transition from NAFL to NASH, providing insights that could facilitate the discovery of novel biomarkers and therapeutic targets for NAFLD.

Alterations in the diversity, composition and function of the gut microbiota in Uyghur individuals with sarcopenia

BACKGROUND

Research on the gut microbiota has emerged as a new direction for understanding pathophysiologic changes in diseases associated with aging, such as sarcopenia. Several studies have shown that there are differences in the gut microbiota between individuals with sarcopenia and without sarcopenia. However, these differences are not consistent across regions and ethnic groups, and additional research is needed.

METHODS

In this study, we collected fresh fecal samples from 31 Uyghur individuals with sarcopenia and 31 healthy controls. We used 16S rRNA sequencing to obtain fecal base sequences and analyzed the diversity, composition and function of the gut microbiota.

RESULTS

There was no significant difference in alpha diversity between the sarcopenia group and the healthy control group (P > 0.05). There was a significant difference in beta diversity between the groups (P < 0.05). In the sarcopenia group, the abundances of Alloprevotella, un_f_Prevotellaceae, Anaerovibrio, Prevotellaceae_NK3B31_group, Mitsuokella, Prevotella and Allisonella were lower than those in the heathy control group, and the abundances of Flavobacteriales, Flavobacteriaceae, Catenibacterium, Romboutsia, Erysipelotrichaceae_UCG-003, GCA-900066575, Lachnospiraceae_FCS020_group, and un_f_Flavobacteriaceae were higher than those in the heathy control group. Linear discriminant analysis effect size (LEfSe) revealed that the microbial species in the control group that were significantly different from those in the sarcopenia group were concentrated in the genus Alloprevotella, while the species in the sarcopenia group were concentrated in the genus Catenibacterium. Functional prediction analysis revealed that D-alanine, glycine, serine, and threonine metabolism and transcription machinery, among others, were enriched in the sarcopenia group, which indicated that metabolic pathways related to amino acid metabolism and nutrient transport may be regulated to varying degrees in the pathophysiological context of sarcopenia.

CONCLUSIONS

There were significant differences in the composition and function of the gut microbiota between Xinjiang Uyghur sarcopenia individuals and healthy individuals. These findings might aid in the development of probiotics or microbial-based therapies for sarcopenia in Uyhur individuals.

Association of skeletal muscle function, quantity, and quality with gut microbiota in Japanese adults: A cross-sectional study

AIM

The gut microbiota has emerged as a new intervention target for sarcopenia. Prior studies in humans have focused on the association between gut microbiota and skeletal muscle quantity, while the evidence on muscle function and quality is lacking. This study aimed to identify gut microbiota genera associated with skeletal muscle function, quantity, and quality in a general population of Japanese adults.

METHODS

This cross-sectional study included 164 participants aged 35-80 years, women and men recruited from urban areas of Japan. Fecal samples were collected and analyzed using 16S rRNA gene amplicon sequencing. Skeletal muscle function was measured using handgrip strength and leg extension power (LEP), while skeletal muscle mass was estimated using bioelectrical impedance analysis. Phase angle was used as a measure of skeletal muscle quality. Multivariate linear regression analysis stratified by age group was used to examine the association between the dominant genera of the gut microbiota and skeletal muscle variables.

RESULTS

A significant association was found between Bacteroides and Prevotella 9 with LEP only in the ≥60 years group. When both Bacteroides and Prevotella 9 were included in the same regression model, only Bacteroides remained consistently and significantly associated with LEP. No significant associations were observed between skeletal muscle mass, handgrip strength, and phase angle and major gut microbiota genera.

CONCLUSIONS

In this study, we observed a significant positive association between Bacteroides and leg muscle function in older adults. Further studies are required to elucidate the underlying mechanisms linking Bacteroides to lower-extremity muscle function. Geriatr Gerontol Int 2024; 24: 53-60.

Metabolites of the gut microbiota may serve as precise diagnostic markers for sarcopenia in the elderly

Sarcopenia, a disease recognized by the World Health Organization, has posed a great challenge to the world in the current aging society. The vital role of the gut microbiome through the gut-muscle axis in sarcopenia is increasingly recognized. However, the working mechanisms by which the gut microbiota functions have not been fully explored in the multi-omics field. Here, we designed a cross-sectional study that recruited patients (n = 32) with sarcopenia and healthy old adults (n = 31). Diagnosis of sarcopenia was based on the Asian Working Group for Sarcopenia (AWGS) in 2019 criteria. Muscle mass was represented by appendicular skeletal muscle mass measured by using direct segmental multi-frequency bioelectrical impedance and muscle strength was evaluated using the handgrip strength. The Short Physical Performance Battery, the 5-time Chair Stand Test, and the 4-metre Walk Test were used to assess physical performance. Shotgun metagenomic sequencing was used to profile the gut microbiome in order to identify its construction and function. Metabolome based on untargeted metabolomics was applied to describe the features and structure of fecal metabolites. In clinical indexes including triglycerides and high-density lipoprotein cholesterol, we noted a significant decrease in triglycerides (TG) and a significant increase in high-density lipoprotein cholesterol (HDL-C) in patients with sarcopenia. Appendicular skeletal muscle mass of patients with sarcopenia was lower than the health group. Based on intestinal metagenomic and fecal metabolomic profiles, we found that the gut microbiome and metabolome were disturbed in patients with sarcopenia, with significant decreases in bacteria such as Bifidobacterium longum, Bifidobacterium pseudocatenulatum, and Bifidobacterium adolescentis, as well as metabolites such as shikimic acid. Also, we plotted supervised classification models at the species level of gut bacteria (AUC = 70.83-88.33) and metabolites (AUC = 92.23-98.33) based on machine learning, respectively. Based on the gut-muscle axis network, a potential mechanism is proposed along the gut microbiome - key metabolites - clinical index, that Phascolarctobacterium faecium affects appendicular skeletal muscle mass, calf circumference, handgrip strength, and BMI via Shikimic acid metabolites. This study elucidates the potential mechanisms by which the gut microbiome influences the progress of sarcopenia through metabolites and provides a meaningful theoretical foundation for reference in the diagnosis and treatment of sarcopenia.

Gut-joint axis in knee synovitis: gut fungal dysbiosis and altered fungi-bacteria correlation network identified in a community-based study

OBJECTIVES

Knee synovitis is a highly prevalent and potentially curable condition for knee pain; however, its pathogenesis remains unclear. We sought to assess the associations of the gut fungal microbiota and the fungi-bacteria correlation network with knee synovitis.

METHODS

Participants were derived from a community-based cross-sectional study. We performed an ultrasound examination of both knees. A knee was defined as having synovitis if its synovium was ≥4 mm and/or Power Doppler (PD) signal was within the knee synovium area (PD synovitis). We collected faecal specimens from each participant and assessed gut fungal and bacterial microbiota using internal transcribed spacer 2 and shotgun metagenomic sequencing. We examined the relation of α-diversity, β-diversity, the relative abundance of taxa and the interkingdom correlations to knee synovitis.

RESULTS

Among 977 participants (mean age: 63.2 years; women: 58.8%), 191 (19.5%) had knee synovitis. β-diversity of the gut fungal microbiota, but not α-diversity, was significantly associated with prevalent knee synovitis. The fungal genus Schizophyllum was inversely correlated with the prevalence and activity (ie, control, synovitis without PD signal and PD synovitis) of knee synovitis. Compared with those without synovitis, the fungi-bacteria correlation network in patients with knee synovitis was smaller (nodes: 93 vs 153; edges: 107 vs 244), and the average number of neighbours was fewer (2.3 vs 3.2).

CONCLUSION

Alterations of gut fungal microbiota and the fungi-bacteria correlation network are associated with knee synovitis. These novel findings may help understand the mechanisms of the gut-joint axis in knee synovitis and suggest potential targets for future treatment.

Functional alterations and predictive capacity of gut microbiome in type 2 diabetes

The gut microbiome plays a significant role in the development of Type 2 Diabetes Mellitus (T2DM), but the functional mechanisms behind this association merit deeper investigation. Here, we used the nanopore sequencing technology for metagenomic analyses to compare the gut microbiome of individuals with T2DM from the United Arab Emirates (n = 40) with that of control (n = 44). DMM enterotyping of the cohort resulted concordantly with previous results, in three dominant groups Bacteroides (K1), Firmicutes (K2), and Prevotella (K3) lineages. The diversity analysis revealed a high level of diversity in the Firmicutes group (K2) both in terms of species richness and evenness (Wilcoxon rank-sum test, p value < 0.05 vs. K1 and K3 groups), consistent with the Ruminococcus enterotype described in Western populations. Additionally, functional enrichment analyses of KEGG modules showed significant differences in abundance between individuals with T2DM and controls (FDR < 0.05). These differences include modules associated with the degradation of amino acids, such as arginine, the degradation of urea as well as those associated with homoacetogenesis. Prediction analysis with the Predomics approach suggested potential biomarkers for T2DM, including a balance between a depletion of Enterococcus faecium and Blautia lineages with an enrichment of Absiella spp or Eubacterium limosum in T2DM individuals, highlighting the potential of metagenomic analysis in predicting predisposition to diabetic cardiomyopathy in T2DM patients.

Association of indoor solid fuel use and long-term exposure to ambient PM2.5 with sarcopenia in China: A nationwide cohort study

BACKGROUND

Little is known about the association between air pollution exposure and sarcopenia in Asia. We aimed to investigate the associations of indoor solid fuel use and long-term exposure to ambient fine particulate matter (PM2.5) with sarcopenia in China.

METHODS

Using a nationally population-representative study, 12,723 participants aged at least 45 years across 125 cities from the China Health and Retirement Longitudinal Study were enrolled in 2011, and further 3110 participants were followed up until 2013. Sarcopenia status was classified according to the Asian Working Group for Sarcopenia 2019 criteria. Household fuel types used for heating and cooking were assessed using a standard questionnaire. Ambient annual PM2.5 was estimated using satellite-based spatiotemporal models. Multinomial logistic regression as well as the multiplicative interaction and additive interaction analysis were used to explore the associations of indoor solid fuel and ambient PM2.5 with different status of sarcopenia.

RESULTS

Of the 12,723 participants, 6071 (47.7%) were men. In the cross-sectional analyses, compared with clean fuel, using solid fuel for heating and cooking, separately or simultaneously, was significantly associated with a higher risk of both possible sarcopenia and sarcopenia. Each 10 μg/m3 increment of PM2.5 was positively related to possible sarcopenia (adjusted odds ratio, [aOR] 1.04, 1.02-1.07) and sarcopenia (1.06, 1.01-1.12). We found a significant interaction between solid fuel use for heating and ambient PM2.5 exposure with possible sarcopenia. During a two-year follow-up, solid fuel use was associated with incident possible sarcopenia (aOR 1.59, 1.17-2.15). These associations did not differ by sex and age, while participants living in a house with poor cleanliness might have a higher risk of sarcopenia.

CONCLUSIONS

Indoor solid fuel use and long-term exposure to ambient PM2.5 were associated with a higher risk of sarcopenia among Chinese adults. These findings provide implications for promoting healthy aging by reducing air pollution.

The microbiome and ovarian cancer: insights, implications, and therapeutic opportunities

Ovarian cancer is the leading cause of gynecologic cancer death in the United States. Most ovarian cancer patients are diagnosed with advanced-stage disease, which poses a challenge for early detection and effective treatment. At present, cytoreductive surgery and platinum-based chemotherapy are foundational for patients with newly diagnosed ovarian cancer, but unfortunately, most patients will recur and die of their disease. Therefore, there is a significant need to seek innovative, novel approaches for early detection and to overcome chemoresistance for ovarian cancer patients. The microbiome, comprising diverse microbial communities inhabiting various body sites, is vital in maintaining human health. Changes to the diversity and composition of the microbial communities impact the microbiota-host relationship and are linked to diseases, including cancer. The microbiome contributes to carcinogenesis through various mechanisms, including altered host immune response, modulation of DNA repair, upregulation of pro-inflammatory pathways, altered gene expression, and dysregulated estrogen metabolism. Translational and clinical studies have demonstrated that specific microbes contribute to ovarian cancer development and impact chemotherapy’s efficacy. The microbiome is malleable and can be altered through different approaches, including diet, exercise, medications, and fecal microbiota transplantation. This review provides an overview of the current literature regarding ovarian cancer and the microbiome of female reproductive and gastrointestinal tracts, focusing on mechanisms of carcinogenesis and options for modulating the microbiota for cancer prevention and treatment. Advancing our understanding of the complex relationship between the microbiome and ovarian cancer may provide a novel approach for prevention and therapeutic modulation in the future.

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.

High-throughput sequencing analysis of the characteristics of the gut microbiota in aged patients with sarcopenia

BACKGROUND

The gut microbiota is a complex microbial community that changes in response to various intestinal diseases, including aging-related diseases such as sarcopenia. Several studies have shown that the metabolites of the gut microbiota affect the dynamic balance of the skeletal muscle. However, the effect of gut microbiota imbalance on sarcopenia is still largely unknown.

METHODS

We collected the baseline characteristics and fecal samples of 14 patients with sarcopenia and 21 patients without sarcopenia, and used the 16S rRNA sequencing technology to analyze the differences in the gut microbiota in the two groups. α-diversity and β-diversity were employed to assess the abundance and diversity of species and variations in microflora composition, respectively. Moreover, Tax4Fun was employed to predict the functional capacities of the microbial communities.

RESULTS

In the sarcopenia group, the abundances of beneficial bacteria such as Bacteroides, Faecalibacterium, Fusobacterium, and Prevotella were reduced, whereas those of pathogenic bacteria, such as Escherichia-Shigella and Klebsiella, were increased. The genera and species of the family Enterobacteriaceae were the main pathogenic bacteria in patients with sarcopenia, and Escherichia-Shigella and Klebsiella could be used as key biomarkers of sarcopenia. The defective protein processing and amino acid synthesis pathways in patients with sarcopenia indicated that protein synthesis and nutrient transport may be damaged. Moreover, the abundances of Escherichia-Shigella and Enterobacteriaceae have been found to have a negative correlation with muscle mass and were the main parameters predicting the change in muscle mass.

CONCLUSIONS

In this study, we have identified changes in the gut microbiota of sarcopenic individuals, which were linked to the loss of muscle mass and function. Escherichia-Shigella is a conditional pathogen of sarcopenic patients, and its levels are found to have a significant negative correlation with muscle mass.

Prevotella copri alleviates sarcopenia via attenuating muscle mass loss and function decline

BACKGROUND

The gut microbiome and fecal metabolites have been found to influence sarcopenia, but whether there are potential bacteria that can alleviate sarcopenia has been under-investigated, and the molecular mechanism remains unclear.

METHODS

To investigate the relationships between the gut microbiome, fecal metabolites and sarcopenia, subjects were selected from observational multi-ethnic study conducted in Western China. Sarcopenia was diagnosed according to the criteria of the Asian Working Group for Sarcopenia 2014. The gut microbiome was profiled by shotgun metagenomic sequencing. Untargeted metabolomic analysis was performed to analyse the differences in fecal metabolites. We investigated bacterium with the greatest relative abundance difference between healthy individuals and sarcopenia patients, and the differences in metabolites associated with the bacteria, to verify its effects on muscle mass and function in a mouse model.

RESULTS

The study included 283 participants (68.90% females, mean age: 66.66 years old) with and without sarcopenia (141 and 142 participants, respectively) and from the Han (98 participants), Zang (88 participants) and Qiang (97 participants) ethnic groups. This showed an overall reduction (15.03% vs. 20.77%, P = 0.01) of Prevotella copri between the sarcopenia and non-sarcopenia subjects across the three ethnic groups. Functional characterization of the differential bacteria showed enrichment (odds ratio = 15.97, P = 0.0068) in branched chain amino acid (BCAA) metabolism in non-sarcopenia group. A total of 13 BCAA and their derivatives have relatively low levels in sarcopenia. In the in vivo experiment, we found that the blood BCAA level was higher in the mice gavaged with live P. copri (LPC) (P < 0.001). The LPC mice had significantly longer wire and grid hanging time (P < 0.02), longer time on rotor (P = 0.0001) and larger grip strength (P < 0.0001), indicating better muscle function. The weight of gastrocnemius mass and rectus femoris mass (P < 0.05) was higher in LPC mice. The micro-computed tomography showed a larger leg area (P = 0.0031), and a small animal analyser showed a higher lean mass ratio in LPC mice (P = 0.0157), indicating higher muscle mass.

CONCLUSIONS

The results indicated that there were lower levels of both P. copri and BCAA in sarcopenia individuals. In vivo experiments, gavage with LPC could attenuate muscle mass and function decline, indicating alleviating sarcopenia. This suggested that P. copri may play a therapeutic potential role in the management of sarcopenia.

Trial in Elderly with Musculoskeletal Problems due to Underlying Sarcopenia-Faeces to Unravel the Gut and Inflammation Translationally (TEMPUS-FUGIT): protocol of a cross-sequential study to explore the gut-muscle axis in the development and treatment of sarcopenia in community-dwelling older adults

BACKGROUND

Gut microbiota (GM) might play a role in muscle metabolism and physiological processes through a hypothesized gut-muscle axis, influencing muscle mass and function and thus, sarcopenia. The Trial in Elderly with Musculoskeletal Problems due to Underlying Sarcopenia-Faeces to Unravel the Gut and Inflammation Translationally (TEMPUS-FUGIT) aims to explore the gut-muscle axis in sarcopenia.

METHODS

First, in a cross-sectional case-control phase, 100 community-dwelling adults without sarcopenia will be compared to 100 community-dwelling adults (≥ 65 years) with sarcopenia of similar age-, gender and BMI-ratio, participating in the ongoing 'Exercise and Nutrition for Healthy AgeiNg' (ENHANce; NCT03649698) study. Sarcopenia is diagnosed according to the European Working Group on Sarcopenia in Older People 2 (EWGSOP2) criteria. GM composition and intestinal inflammatory markers (fecal calprotectin, lactoferrin and S100A12) will be determined in fecal samples. Systemic inflammatory markers (hs-CRP, IL-4, IL-6, TNF-α, IL-13, IL-1β and creatine kinase) will be determined in fasted blood samples. Both groups will be compared using appropriate statistical testing, whereas linear regression will be used for cross-sectional associations between gut, inflammatory and sarcopenia parameters. Second, in the longitudinal phase, sarcopenic older adults will be requested to deliver five fecal samples during the 12-week intervention to assess the effects of protein, omega-3 and a physical exercise program on the GM.

DISCUSSION

TEMPUS-FUGIT aims to explore the gut-muscle axis by comparing GM composition between sarcopenic and non-sarcopenic older adults and to determine the association of GM with intestinal and systemic inflammatory markers and sarcopenia-defining parameters (muscle mass, muscle strength and physical performance). Furthermore, effects of single or combined, optimized and individualized anabolic interventions (exercise, protein and omega-3 supplementation), on GM will be explored in persons with sarcopenia. TEMPUS-FUGIT aims to impact clinical practice by clarifying the relationship between the gut-muscle axis and sarcopenia. TEMPUS-FUGIT is expected to contribute to the discovery of clinical and microbial biomarkers for sarcopenia and insights in its pathophysiology, opening possible future perspectives for novel sarcopenia treatment strategies targeting GM.

TRIAL REGISTRATION

ClinicalTrails.gov NCT05008770, registered on August 17, 2021; first participant enrolled on September 21 2021.

The gut microbiota from maintenance hemodialysis patients with sarcopenia influences muscle function in mice

Background

Sarcopenia is a common complication in patients undergoing maintenance hemodialysis (MHD). Growing evidence suggests a close relationship between the gut microbiota and skeletal muscle. However, research on gut microbiota in patients with sarcopenia undergoing MHD (MS) remains scarce. To bridge this knowledge gap, we aimed to evaluate the pathogenic influence of gut microbiota in the skeletal muscle of patients with MS, to clarify the causal association between gut microbiota and skeletal muscle symptoms in patients with MS and identify the potential mechanisms underlying this causal association.

Methods

Fecal samples were collected from 10 patients with MS and 10 patients without MS (MNS). Bacteria were extracted from these samples for transplantation. Mice (n=42) were randomly divided into three groups and, after antibiotic treatment, fecal microbiota transplantation (FMT) was performed once a day for 3 weeks. Skeletal muscle and fecal samples from the mice were collected for 16S rRNA gene sequencing and for histological, real-time PCR, and metabolomic analyses.

Results

Mice colonized with gut microbiota from MS patients exhibited notable decreases in muscle function and muscle mass, compared with FMT from patients with MNS. Moreover, 16S rRNA sequencing revealed that the colonization of MS gut microbiota reduced the abundance of Akkermansia in the mouse intestines. Metabolome analysis revealed that seven metabolic pathways were notably disrupted in mice transplanted with MS microbiota.

Conclusion

This study established a connection between skeletal muscle and the gut microbiota of patients with MS, implying that disruption of the gut microbiota may be a driving factor in the development of skeletal muscle disorders in patients undergoing MHD. This finding lays the foundation for understanding the pathogenesis and potential treatment methods for sarcopenia in patients undergoing MHD.

Malnutrition, sarcopenia, and cancer cachexia in gynecologic cancer

Patients with gynecologic cancers are at risk for malnutrition, cancer cachexia, and sarcopenia. Accumulating data supports that malnourished patients with gynecologic cancer have worse overall survival, increased healthcare utilization and costs, and a higher incidence of postoperative complications and treatment toxicity than those who are not malnourished. Malnutrition is defined as insufficient energy intake, leading to altered body composition and subsequent impaired physical and cognitive function, and can result in sarcopenia and cachexia, defined as the loss of lean body mass and loss of body weight respectively. The etiology of cancer-related malnutrition is complex, resulting from a systemic pro-inflammatory state of malignancy with upregulation of muscle degradation pathways and metabolic derangements, including lipolysis and proteolysis, that may not respond to nutritional repletion alone. Numerous validated scoring systems and radiographic measures have been described to define and quantify the severity of malnutrition and muscle loss in both clinical and research settings. "Prehabilitation" and optimization of nutrition and functional status early in therapy may combat the development or worsening of malnutrition and associated syndromes and ultimately improve oncologic outcomes, but limited data exist in the context of gynecologic cancer. Multi-modality nutrition and physical activity interventions have been proposed to combat the biophysical losses related to malnutrition. Several trials are underway in gynecologic oncology patients to address these aims, but significant gaps in knowledge persist. Pharmacologic interventions and potential immune targets for combating cachexia related to malignancy are discussed in this review and may provide opportunities to target disease and cachexia. This article reviews currently available data regarding the implications, diagnostics, physiology, and intervention strategies for gynecologic oncology patients with malnutrition and its associated conditions.

The Role of Ion Channels in Functional Gastrointestinal Disorders (FGID): Evidence of Channelopathies and Potential Avenues for Future Research and Therapeutic Targets

Several gastrointestinal (GI) tract abnormalities, including visceral hypersensitivity, motility, and intestinal permeability alterations, have been implicated in functional GI disorders (FGIDs). Ion channels play a crucial role in all the functions mentioned above. Hormones and natural molecules modulate these channels and represent targets of drugs and bacterial toxins. Mutations and abnormal functional expression of ion channel subunits can lead to diseases called channelopathies. These channelopathies in gastroenterology are gaining a strong interest, and the evidence of co-relationships is increasing. In this review, we describe the correlation status between channelopathies and FGIDs. Different findings are available. Among others, mutations in the ABCC7/CFTR gene have been described as a cause of constipation and diarrhea. Mutations of the SCN5A gene are instead associated with irritable bowel syndrome. In contrast, mutations of the TRPV1 and TRPA genes of the transient receptor potential (TRP) superfamily manifest hypersensitivity and visceral pain in sensory nerves. Recently, mice and humans affected by Cantu syndrome (CS), which is associated with the mutations of the KCNJ8 and ABCC9 genes encoding for the Kir6.1 and SUR2 subunits, showed dysfunction of contractility throughout the intestine and death in the mice after the weaning on solid food. The discovery of a correlation between channelopathies and FIGD opens new avenues for discovering new direct drug targets for specific channelopathies, leading to significant implications for diagnosing and treating functional GI diseases.

Impact of household solid fuel use on sarcopenia in China: A nationwide analysis

BACKGROUND

Household air pollution from solid fuel combustion is a leading cause of age-related diseases worldwide. However, little is known about the association between indoor solid fuel use and sarcopenia, especially in developing countries.

METHODS

A total of 10,261 and 5129 participants from the China Health and Retirement Longitudinal Study were enrolled in the cross-sectional and follow-up analysis, respectively. The effects of household solid fuel use (for cooking and heating) on sarcopenia were evaluated using generalized linear models in the cross-sectional analysis and Cox proportional hazards regression models in the longitudinal analysis.

RESULTS

The prevalence of sarcopenia in the total population, clean cooking fuel users, and solid cooking fuel users were 13.6 % (1396/10,261), 9.1 % (374/4114), and 16.6 % (1022/6147), respectively. A similar pattern was observed for heating fuel users, with a higher prevalence of sarcopenia among solid fuel users (15.5 %) than among clean fuel users (10.7 %). In the cross-sectional analysis, solid fuel use for cooking/heating, separately or simultaneously, was positively associated with an elevated risk of sarcopenia after adjusting for potential confounders. During the four-years follow-up period, 330 participants (6.4 %) with sarcopenia were identified. The multivariate-adjusted hazard ratio (HR) (95 % confidence interval [95 % CI]) for solid cooking fuel users and solid heating fuel users was 1.86(95 % CI:1.43-2.41) and 1.32(95 % CI:1.05-1.66), respectively. Moreover, compared with persistent clean fuel users, participants who switched from clean to solid fuel for heating appeared to have an increased risk of sarcopenia (HR:1.58; 95 % CI:1.08-2.31).

CONCLUSIONS

Our findings show that household solid fuel use is a risk factor for sarcopenia development among middle-aged and older Chinese adults. The transition from solid to clean fuel use may help reduce the burden of sarcopenia in developing countries.

Relationships between sarcopenia, nutrient intake, and gut microbiota in Chinese community-dwelling older women

BACKGROUND

The relationship among gut microbiota, sarcopenia components, and influencing factors in female sarcopenic patients has been poorly investigated.

METHODS

Female participants completed questionnaires of physical activity and dietary frequency and were assessed for the presence of sarcopenia by the Asian Working Group of Sarcopenia 2019 (AWGS 2019) criteria. Fecal samples were collected from 17 sarcopenia and 30 non-sarcopenia subjects for 16S sequencing and short chain fatty acid (SCFA) detection.

RESULTS

The prevalence of sarcopenia was 19.20% among 276 participants. The dietary protein, fat, dietary fiber, vitamin B1, niacin, vitamin E, phosphorus, magnesium, iron, zinc, and cooper intake of sarcopenia were all remarkably low. In addition, the richness of gut microbiota (Chao1 and ACE indexes) was considerably reduced in sarcopenic patients, and the sarcopenic gut microbiota and its metabolite were decreased in Firmicutes/Bacteroidetes, Agathobacter, Dorea and Butyrate and were enriched in Shigella and Bacteroides. Correlation analysis showed that Agathobacter and Acetate were positively correlated with grip strength and gait speed, respectively, and Bifidobacterium was negatively correlated with grip strength and appendicular skeletal muscle index (ASMI). Moreover, the protein intake was positively related to Bifidobacterium.

CONCLUSIONS

This cross-sectional study revealed the alterations of gut microbiota composition, SCFA, and nutrient intake in women with sarcopenia and their relation to sarcopenic components. These results provide insights into further studies on the role of nutrition and gut microbiota in sarcopenia and its use as a therapeutic approach.

Association of gut microbiota and SCFAs with finishing weight of Diannan small ear pigs

Finishing weight is a key economic trait in the domestic pig industry. Evidence has linked the gut microbiota and SCFAs to health and production performance in pigs. Nevertheless, for Diannan small ear (DSE) pigs, a specific pig breed in China, the potential effect of gut microbiota and SCFAs on their finishing weight remains unclear. Herein, based on the data of the 16S ribosomal RNA gene and metagenomic sequencing analysis, we found that 13 OTUs could be potential biomarkers and 19 microbial species were associated with finishing weight. Among these, carbohydrate-decomposing bacteria of the families Streptococcaceae, Lactobacillaceae, and Prevotellaceae were positively related to finishing weight, whereas the microbial taxa associated with intestinal inflammation and damage exhibited opposite effects. In addition, interactions of these microbial species were found to be linked with finishing weight for the first time. Gut microbial functional annotation analysis indicated that CAZymes, such as glucosidase and glucanase could significantly affect finishing weight, given their roles in increasing nutrient absorption efficiency. Kyoto Encyclopedia of Genes and Genomes (KEGG) Orthologies (KOs) and KEGG pathways analysis indicated that glycolysis/gluconeogenesis, phosphotransferase system (PTS), secondary bile acid biosynthesis, ABC transporters, sulfur metabolism, and one carbon pool by folate could act as key factors in regulating finishing weight. Additionally, SCFA levels, especially acetate and butyrate, had pivotal impacts on finishing weight. Finishing weight-associated species Prevotella sp. RS2, Ruminococcus sp. AF31-14BH and Lactobacillus pontis showed positive associations with butyrate concentration, and Paraprevotella xylaniphila and Bacteroides sp. OF04-15BH were positively related to acetate level. Taken together, our study provides essential knowledge for manipulating gut microbiomes to improve finishing weight. The underlying mechanisms of how gut microbiome and SCFAs modulate pigs' finishing weight required further elucidation.

Gut microbiome changes due to sleep disruption in older and younger individuals: a case for sarcopenia?

Major hallmarks of functional loss, loss of metabolic and musculoskeletal health and (multi)morbidity with aging are associated with sleep disturbances. With poor sleep shifts in gut microbial composition commonly manifest, which could mediate the pro-inflammatory state between sleep disturbances and sarcopenia. This systematic review presents the recent evidence on how sleep disturbances throughout the lifespan associate with and contribute to gut microbial composition changes, proposing a mechanism to understand the etiology of sarcopenia through sleep disturbances. The relationship between disturbed sleep and clinically relevant gut microbiota composition on health aspects of aging is discussed. A search was performed in PubMed, Cochrane Library, Scopus, Web of Science using keywords including (microbio* OR microflora) AND (sleep OR sleep disorder). Six cross-sectional population-based studies and five experimental clinical trials investigating healthy individuals with ages ranging from 4 to 71 were included. The cross-sectional studies reported similarities in associations with sleep disturbance and gut microbial diversity. In older adults, shorter sleep duration is associated with an increase in pro-inflammatory bacteria whereas increasing sleep quality is positively associated with an increase of beneficial Verrucomicrobia and Lentisphaerae phyla. In young adults, the effect of sleep disruption on gut microbiome composition, specifically the ratio of beneficial Firmicutes over Bacteroidetes phyla, remains contradictory and unclear. The findings of this review warrant further research in the modulation of the gut microbiome linking poor sleep with muscle-catabolic consequences throughout the lifespan.