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

New trends in supportive care of head and neck cancers

PURPOSE OF REVIEW

Supportive care plays a vital role in the management of head and neck cancer (HNC) patients, as the disease often affects a frail and older population that is treated with multiple strategies and is associated with severe symptoms. We will focus on mucositis, dermatitis, dysphagia, pain, cachexia, and infections, as they are among the most common and challenging symptoms encountered.

RECENT FINDINGS

Efforts have focused on multiomics approaches to decipher the complex biological pathways that drive symptom onset and treatment-related toxicities, with the aim of developing novel therapeutic strategies. A notable example is ponsegromab, a monoclonal antibody designed to target cancer cachexia. Other promising areas of research, such as machine-learning models and the role of oral and gut microbiota on cachexia and mucositis, are actively being explored; however, their impact to date remains limited.

SUMMARY

In recent years, new knowledge has emerged regarding the underlying causes and predictive models for the supportive care of HNC patients. Unfortunately, this expanding body of knowledge primarily adds to complexity without translating into practical applications or substantial improvements for patients. Future efforts should prioritize the standardization of therapeutic algorithms, and the generation of robust evidence based on existing preclinical models.

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.

Bifidobacterium adolescentis-derived nicotinic acid improves host skeletal muscle mitochondrial function to ameliorate sarcopenia

Sarcopenia significantly diminishes quality of life and increases mortality risk in older adults. While the connection between the gut microbiome and muscle health is recognized, the underlying mechanisms are poorly understood. In this study, shotgun metagenomics revealed that Bifidobacterium adolescentis is notably depleted in individuals with sarcopenia, correlating with reduced muscle mass and function. This finding was validated in aged mice. Metabolomics analysis identified nicotinic acid as a key metabolite produced by B. adolescentis, linked to improvements in muscle mass and functionality in individuals with sarcopenia. Mechanistically, nicotinic acid restores nicotinamide adenine dinucleotide (NAD+) levels in muscle, inhibits the FoxO3/Atrogin-1/Murf-1 axis, and promotes satellite cell proliferation, reducing muscle atrophy. Additionally, NAD+ activation enhances the silent-information-regulator 1 (SIRT1)/peroxisome-proliferator-activated-receptor-γ-coactivator 1-alpha (PGC-1α) axis, stimulating mitochondrial biogenesis and promoting oxidative metabolism in slow-twitch fibers, ultimately improving muscle function. Our findings suggest that B. adolescentis-derived nicotinic acid could be a promising therapeutic strategy for individuals with sarcopenia.

Therapeutic Strategies to Modulate Gut Microbial Health: Approaches for Chronic Metabolic Disorder Management

Numerous recent studies have suggested that the composition of the intestinal microbiota can trigger metabolic disorders, such as diabetes, prediabetes, obesity, metabolic syndrome, sarcopenia, dyslipidemia, hyperhomocysteinemia, and non-alcoholic fatty liver disease. Since then, considerable effort has been made to understand the link between the composition of intestinal microbiota and metabolic disorders, as well as the role of probiotics in the modulation of the intestinal microbiota. The aim of this review was to summarize the reviews and individual articles on the state of the art regarding ideal therapy with probiotics and prebiotics in order to obtain the reversion of dysbiosis (alteration in microbiota) to eubiosis during metabolic diseases, such as diabetes, prediabetes, obesity, hyperhomocysteinemia, dyslipidemia, sarcopenia, and non-alcoholic fatty liver diseases. This review includes 245 eligible studies. In conclusion, a condition of dysbiosis, or in general, alteration of the intestinal microbiota, could be implicated in the development of metabolic disorders through different mechanisms, mainly linked to the release of pro-inflammatory factors. Several studies have already demonstrated the potential of using probiotics and prebiotics in the treatment of this condition, detecting significant improvements in the specific symptoms of metabolic diseases. These findings reinforce the hypothesis that a condition of dysbiosis can lead to a generalized inflammatory picture with negative consequences on different organs and systems. Moreover, this review confirms that the beneficial effects of probiotics on metabolic diseases are promising, but more research is needed to determine the optimal probiotic strains, doses, and administration forms for specific metabolic conditions.

The gut microbiota genus Blautia is associated with skeletal muscle mass reduction in community-dwelling older Japanese adults: the Wakayama Study

PURPOSE

This cross-sectional study examined the gut microbiota species associated with skeletal muscle mass reduction in a community-based sample of older Japanese adults.

METHODS

The study included 744 participants (320 men and 424 women) aged 65-89 years (mean age: 73 years) with no history of treatment for colorectal, chronic kidney, or liver diseases. Bioelectrical impedance analysis was performed to estimate the appendicular skeletal muscle mass (ASM) of each participant. The gut microbiota composition was assessed using next-generation sequencing targeting the V3-V4 regions of the prokaryotic 16S rRNA genes. A self-administered questionnaire was used to evaluate daily living habits, including food intake associated with maintaining the gut microbiota.

RESULTS

Among the participants, those with reduced muscle mass (defined as an ASM index of less than 4.4 kg/m2 for men and 3.7 kg/m2 for women) had significantly higher levels of the genus Blautia when compared with those with normal muscle mass (P = 0.009). Logistic regression analysis revealed that the association between the genus Blautia and skeletal muscle mass remained significant even after adjusting for multiple confounding factors (P = 0.012). Additionally, an increase in the genus Blautia was positively associated with excessive alcohol consumption (≥ 20 g/day, β = 0.125, P = 0.002) and negatively associated with regular yogurt intake (≥ 1 time/week, β = -0.101, P = 0.010), independent of other lifestyle and dietary factors.

CONCLUSION

Elevated levels of the genus Blautia were associated with reduced skeletal muscle mass in older Japanese adults, suggesting that improving the gut microbiota may be a potential approach to preserving muscle mass among this population.

SYISL Knockout Promotes Embryonic Muscle Development of Offspring by Modulating Maternal Gut Microbiota and Fetal Myogenic Cell Dynamics

Embryonic muscle fiber formation determines post-birth muscle fiber totals. The previous research shows SYISL knockout significantly increases muscle fiber numbers and mass in mice, but the mechanism remains unclear. This study confirms that the SYISL gene, maternal gut microbiota, and their interaction significantly affect the number of muscle fibers in mouse embryos through distinct mechanisms, as SYISL knockout alters maternal gut microbiota composition and boosts butyrate levels in embryonic serum. Both fecal microbiota transplantation and butyrate feeding significantly increase muscle fiber numbers in offspring, with butyrate inhibiting histone deacetylases and increasing histone acetylation in embryonic muscle. Combined analysis of RNA-seq between wild-type and SYISL knockout mice with ChIP-seq for H3K9ac and H3K27ac reveals that SYISL and maternal microbiota interaction regulates myogenesis via the butyrate-HDAC-H3K9ac/H3K27ac pathway. Furthermore, scRNA-seq analysis shows that SYISL knockout alone significantly increases the number and proportion of myogenic cells and their dynamics, independently of regulating histone acetylation levels. Cell communication analysis suggests that this may be due to the downregulation of signaling pathways such as MSTN and TGFβ. Overall, multiple pathways are highlighted through which SYISL influences embryonic muscle development, offering valuable insights for treating muscle diseases and improving livestock production.

Ningxiang pig-derived lactobacillus reuteri modulates host intramuscular fat deposition via branched-chain amino acid metabolism

BACKGROUND

Gut microbiota has been extensively demonstrated to modulate host lipid metabolism. Higher intramuscular fat (IMF) accumulation in Chinese indigenous breed pigs is associated with their special gut microbiota structure. However, the specific microbes and metabolic pathways responsible for lipid deposition are still poorly understood.

RESULTS

In the present study, a comparative analysis of the gut microbiota and metabolome in obese Ningxiang (NX) pigs and lean Duroc × Landrace × Yorkshire (DLY) pigs was conducted. The results revealed a higher abundance of gut lactobacilli and a correlation of branched-chain amino acid (BCAA) metabolism pathway in NX pigs. We proceeded to verify the roles of various lactobacilli strains originating from NX pigs in BCAA metabolism and lipids deposition in SD rats. We demonstrated that L. reuteri is a fundamental species responsible for modulating lipid deposition in NX pigs and that increased circulating levels of BCAA are positively linked to greater lipid deposition. Additionally, it has been verified that L. reuteri originating from NX pigs has the ability to improve BCAA synthesis in the gut and enhance IMF content in lean DLY pigs. The expression of genes related to lipid synthesis was also significantly upregulated.

CONCLUSIONS

Taken together, our results imply that NX pig-derived L. reuteri regulates BCAA metabolism and plays a potential role in improving the meat quality of lean pig breeds through modulation of host intramuscular lipid deposition. The results provide a new strategy for improving the meat quality of commercial pigs by influencing host metabolism through supplementing dietary additives. Video Abstract.

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.

A framework of biomarkers for skeletal muscle aging: a consensus statement by the Aging Biomarker Consortium

The skeletal muscle is an important organ for movement and metabolism in human body, and its physiological aging underlies the occurrence of muscle atrophy and sarcopenia. China has the largest aging population in the world and is facing a grand challenge with how to prevent and treat skeletal muscle aging-related diseases. To address this difficult problem, the Aging Biomarker Consortium (ABC) of China has reached an expert consensus on biomarkers of skeletal muscle aging by synthesizing literatures and insights from scientists and clinicians. This consensus attempts to provide a comprehensive assessment of biomarkers associated with skeletal muscle aging, and proposes a systematic framework to classify them into three dimensions: functional, structural, and humoral. Within each dimension, the experts recommend clinically relevant biomarkers for skeletal muscle aging. This consensus aims to lay the foundation for future research on skeletal muscle aging, facilitating precise prediction, diagnosis, and treatment of skeletal muscle aging and sarcopenia. It is anticipated to make significant contributions to healthy aging of skeletal muscle in the elderly population in China and around the world as well.

The recent development, application, and future prospects of muscle atrophy animal models

Muscle atrophy, characterized by the loss of muscle mass and function, is a hallmark of sarcopenia and cachexia, frequently associated with aging, malignant tumors, chronic heart failure, and malnutrition. Moreover, it poses significant challenges to human health, leading to increased frailty, reduced quality of life, and heightened mortality risks. Despite extensive research on sarcopenia and cachexia, consensus in their assessment remains elusive, with inconsistent conclusions regarding their molecular mechanisms. Muscle atrophy models are crucial tools for advancing research in this field. Currently, animal models of muscle atrophy used for clinical and basic scientific studies are induced through various methods, including aging, genetic editing, nutritional modification, exercise, chronic wasting diseases, and drug administration. Muscle atrophy models also include in vitro and small organism models. Despite their value, each of these models has certain limitations. This review focuses on the limitations and diverse applications of muscle atrophy models to understand sarcopenia and cachexia, and encourage their rational use in future research, therefore deepening the understanding of underlying pathophysiological mechanisms, and ultimately advancing the exploration of therapeutic strategies for sarcopenia and cachexia.

Increased rumen Prevotella enhances BCAA synthesis, leading to synergistically increased skeletal muscle in myostatin-knockout cattle

Myostatin (MSTN) is a negative regulator of muscle growth, and its relationship with the gut microbiota is not well understood. In this study, we observed increase muscle area and branched-chain amino acids (BCAAs), an energy source of muscle, in myostatin knockout (MSTN-KO) cattle. To explore the link between increased BCAAs and rumen microbiota, we performed metagenomic sequencing, metabolome analysis of rumen fluid, and muscle transcriptomics. MSTN-KO cattle showed a significant increase in the phylum Bacteroidota (formerly Bacteroidetes), particularly the genus Prevotella (P = 3.12e-04). Within this genus, Prevotella_sp._CAG:732, Prevotella_sp._MSX73, and Prevotella_sp._MA2016 showed significant upregulation of genes related to BCAA synthesis. Functional enrichment analysis indicated enrichment of BCAA synthesis-related pathways in both rumen metagenomes and metabolomes. Additionally, muscle transcriptomics indicated enrichment in muscle fiber and amino acid metabolism, with upregulation of solute carrier family genes, enhancing BCAA transport. These findings suggest that elevated rumen Prevotella in MSTN-KO cattle, combined with MSTN deletion, synergistically improves muscle growth through enhanced BCAA synthesis and transport.

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.

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.

Non-Pharmacological Strategies for Managing Sarcopenia in Chronic Diseases

This article focuses on a range of non-pharmacological strategies for managing sarcopenia in chronic diseases, including exercise, dietary supplements, traditional Chinese exercise, intestinal microecology, and rehabilitation therapies for individuals with limited limb movement. By analyzing multiple studies, the article aims to summarize the available evidence to manage sarcopenia in individuals with chronic diseases. The results strongly emphasize the role of resistance training in addressing chronic diseases and secondary sarcopenia. Maintaining the appropriate frequency and intensity of resistance training can help prevent muscle atrophy and effectively reduce inflammation. Although aerobic exercise has limited ability to improve skeletal muscle mass, it does have some positive effects on physical function. Building upon this, the article explores the potential benefits of combined training approaches, highlighting their helpfulness for overall quality of life. Additionally, the article also highlights the importance of dietary supplements in combating muscle atrophy in chronic diseases. It focuses on the importance of protein intake, supplements rich in essential amino acids and omega-3, as well as sufficient vitamin D to prevent muscle atrophy. Combining exercise with dietary supplements appears to be an effective strategy for preventing sarcopenia, although the optimal dosage and type of supplement remain unclear. Furthermore, the article explores the potential benefits of intestinal microecology in sarcopenia. Probiotics, prebiotics, and bacterial products are suggested as new treatment options for sarcopenia. Additionally, emerging therapies such as whole body vibration training, blood flow restriction, and electrical stimulation show promise in treating sarcopenia with limited limb movement. Overall, this article provides valuable insights into non-pharmacological strategies for managing sarcopenia in individuals with chronic diseases. It emphasizes the importance of a holistic and integrated approach that incorporates exercise, nutrition, and multidisciplinary interventions, which have the potential to promote health in the elderly population. Future research should prioritize high-quality randomized controlled trials and utilize wearable devices, smartphone applications, and other advanced surveillance methods to investigate the most effective intervention strategies for sarcopenia associated with different chronic diseases.

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.