The molecular mechanisms of probiotic strains in improving ageing bone and muscle of d-galactose-induced ageing rats

Lactobacillus fermentum LF31 Supplementation Reversed Atrophy Fibers in a Model of Myopathy Through the Modulation of IL-6, TNF-α, and Hsp60 Levels Enhancing Muscle Regeneration

Background/Objectives: Recent studies have highlighted the role of the gut-muscle axis, suggesting that modulation of the gut microbiota may indirectly benefit skeletal muscle. This study aimed to evaluate the effects of Lactobacillus fermentum (L. fermentum) supplementation in a model of muscle atrophy induced by chronic ethanol (EtOH) intake, focusing on inflammatory and antioxidant mechanisms. Methods: Sixty 12-month-old female Balb/c mice were divided randomly into three groups (n = 20/group): (1) Ethanol (EtOH) group, receiving ethanol daily for 8 and 12 weeks to induce systemic oxidative stress and inflammation; (2) Ethanol + Probiotic (EtOH + P) group, receiving both ethanol and L. fermentum supplementation for the same durations; and (3) Control (Ctrl) group, receiving only water. Muscle samples were analyzed for the fiber morphology, inflammatory markers, oxidative stress indicators, and satellite cell (SC) activity. All data were tested for normality using the Shapiro-Wilk test before applying a parametric analysis. A statistical analysis was performed using one-way ANOVA followed by a Bonferroni post-hoc test. The level of significance was set at p < 0.05. Results: EtOH exposure caused significant atrophy in all muscle fiber types (type I, IIa, and IIb), with the most pronounced effects on oxidative fibers. L. fermentum supplementation significantly reversed atrophy in type I and IIa fibers, accompanied by a significant reduction in IL-6, TNF-α, and Hsp60 expression levels, indicating the protective effect of L. fermentum against oxidative stress and inflammation. Moreover, the probiotic treatment increased MyoD expression in SCs, suggesting enhanced regenerative activity, without histological evidence of fibrosis. Conclusions: These findings suggest that L. fermentum supplementation could counteract EtOH-induced skeletal muscle damage by reducing inflammation and oxidative stress and promoting muscle repair, indicating its potential as an adjuvant, in the therapeutic strategy of models of muscle degeneration.

Zearalenone Exposure Damages Skeletal Muscle Through Oxidative Stress and Is Alleviated by Glutathione, Nicotinamide Mononucleotide, and Melatonin

Zearalenone (ZEN), a mycotoxin, is toxic to skeletal muscle, and the solution to alleviate its damage remains unknown. Here, we analyzed the toxic effect of ZEN on muscle and the mitigation of antioxidants (GSH, NMN, and melatonin) for this toxicity. The results showed that 0.02 mmol/L ZEN inhibited myoblast viability and myogenic differentiation, accompanied by reducing Type I and Type IIA and increasing Type IIX myofibers. Antioxidants (NMN with 0.5 mmol/L, GSH with 1 mmol/L, and melatonin with 1 mmol/L) rescued these phenotypes. Mice that were delivered 3 mg/kg body weight (BW)/day of ZEN by gavage for 35 days exhibited a similar trend of muscle fiber composition, but the gavage of antioxidants (NMN with 500 mg/kg BW/day, GSH with 300 mg/kg BW/day, and melatonin with 100 mg/kg BW/day) abolished this phenotype. Mechanistically, ZEN treatment increased ROS production, resulting in oxidative stress, mitochondrial dysfunction, and, subsequently, myofiber changes. Additionally, ZEN indirectly contributed to its damage, decreasing the abundance of Lactobacillus at the genus level and increasing Streptococcus sp. at the species level, which was associated with lactic acid production. Antioxidants partially rescued this microbiota composition. This study explores ZEN toxicity effects and alleviation of antioxidants, which provides new insights and attenuation solutions for ZEN damage to skeletal muscle. However, the underlying molecular mechanism of ZEN and antioxidants in the skeletal muscle still needs to be explored.

Probiotics and muscle health: the impact of Lactobacillus on sarcopenia through the gut-muscle axis

Sarcopenia refers to the decline in skeletal muscle mass and function. Due to its increased mortality rate and severe disability, the clinical importance of sarcopenia is becoming increasingly prominent. Although the exact cause of sarcopenia is not fully understood, the gut microbiota (GM) plays a crucial role in the pathogenesis of sarcopenia, and increasing evidence suggests that gut dysbiosis may be associated with disease development. In the past few decades, the use of probiotics has surged, few studies have explored their impact on sarcopenia prevention and treatment. Lactobacillus probiotics are commonly used for gut health and immune support, but their mechanism in sarcopenia via the gut-muscle axis remains uncertain. This review highlights the treatment challenges, GM's role in sarcopenia, and the potential of Lactobacillus as an adjunct therapy. In addition, we also discuss the possible mechanisms by which Lactobacillus affect muscle function, such as alleviating inflammatory states, clearing excessive reactive oxygen species (ROS), improving skeletal muscle metabolism, enhancing intestinal barrier function and modulating the gut microbiota and its metabolites. These mechanisms may collectively contribute to the preservation of muscle mass and function, offering a promising avenue for advancing microbial therapies for sarcopenia.

Whole Genome Analysis of Limosilactobacillus fermentum MCC0552 for Probiotic Functionalities and Comparative Genomic Study with Reference Strains

Limosilactobacillus fermentum MCC0552, a potential probiotic was isolated from a dairy source. L. fermentum MCC0552 has been proven earlier to enhance immuno-modulatory response by alleviating inflammatory and diabetic effects. The objective of this study is to analyse the whole genome sequence of L. fermentum MCC0552 for probiotic functionalities and to compare it with the reference strains. The general genomic features of L. fermentum strain MCC0552 were analysed and a phylogenetic dendrogram was generated by considering the genome sequences of reference strains (L. fermentum IFO 3956, F-6, MTCC 5898 and ATCC 14931 or B1 28) which elucidates their evolutionary lineage. Functional analysis of MCC0552 reveals that the strain possess vitamin biosynthesis gene (thiamine and riboflavin) and mucin binding protein (mubp) with comparatively larger in size. HPLC analysis suggests that the strain MCC0552 synthesises class B vitamins (B1, B2, B6, B9 and B12) which increases its significance in nutritional and nutraceutical applications. Genomic island (GI) prediction shows 19 GI in strain MCC0552 genome were identified. GI regions possessed CRISPR cluster genes, mainly type IE, cas2 and type III-A, nucleotide sugar biosynthesis gene, TA system genes, heavy metal associated genes, etc. On further analysis, the strain exhibited the presence of 2 intact prophage regions which ensure its supplementary probiotic attribute. Thus, the present study elaborates on the probiotic potential of strain MCC0552 at the genome level, revealing its remarkable genomic potential and presenting novel prospects for utilising its unique genetic features in diverse scientific fields.

Evaluating the Role of Probiotics, Prebiotics, and Synbiotics Supplementation in Age-related Musculoskeletal Disorders in Older Adults: A Systematic Review

The aim of this systematic review is to evaluate musculoskeletal changes in response to prebiotics, probiotics, or synbiotics supplementation in older adults or in animal models of aging musculoskeletal disorders. A comprehensive search was conducted on electronic databases, including PubMed/Medline, Cochrane, and Web of Science until April 2024. The quality assessment of clinical trials was conducted using the Cochrane Collaboration tool and for animal studies, the SYRCLE's tool was used. Our literature search resulted in 652 studies. After removing duplicates and screening the articles based on their titles and abstracts, we assessed the full text of 112 articles, which yielded 20 clinical trials and 30 animal studies in our systematic review. Most of human and animal studies reported an improvement in physical performance, a decrease in frailty index, and a lower reduction in bone mineral density in the intervention groups. Body composition tends to increase in muscle ratio, muscle mass, and reduce in appendicular lean mass and muscle atrophy. Also, the intervention induced bone turnover and mineral absorption, significantly increasing Ca, P, and Mg absorption and short-chain fatty acid concentration. Additionally, levels of inflammatory markers such as IL1, IL6, IL17, T helper 17, and TNF-α exhibited a decreasing trend, while an increase in IL10 and IFN-γ was observed. Prebiotics, probiotics, or synbiotics supplementations could effectively improve the physical performance and muscle strength and reduce the risk of bone loss and frailty in the elderly.

The potential benefits and mechanisms of protein nutritional intervention on bone health improvement

Osteoporosis commonly occurs in the older people and severe patients, with the main reason of the imbalance of bone metabolism (the rate of bone resorption exceeding the rate of bone formation), resulting in a decrease in bone mineral density and destruction of bone microstructure and further leading to the increased risk of fragility fracture. Recent studies indicate that protein nutritional support is beneficial for attenuating osteoporosis and improving bone health. This review summarized the classical mechanisms of protein intervention for alleviating osteoporosis on both suppressing bone resorption and regulating bone formation related pathways (promoting osteoblasts generation and proliferation, enhancing calcium absorption, and increasing collagen and mineral deposition), as well as the potential novel mechanisms via activating autophagy of osteoblasts, altering bone related miRNA profiles, regulating muscle-bone axis, and modulating gut microbiota abundance. Protein nutritional intervention is expected to provide novel approaches for the prevention and adjuvant therapy of osteoporosis.

D-galactose might mediate some of the skeletal muscle hypertrophy-promoting effects of milk-A nutrient to consider for sarcopenia?

Sarcopenia is a process of progressive aging-associated loss of skeletal muscle mass (SMM) recognized as a serious global health issue contributing to frailty and increased all-cause mortality. Exercise and nutritional interventions (particularly intake of dairy products and milk) demonstrate good efficacy, safety, and broad applicability. Here, we propose that at least some of the well-documented favorable effects of milk and milk-derived protein supplements on SMM might be mediated by D-galactose, a monosaccharide present in large quantities in milk in the form of disaccharide lactose (milk sugar). We suggest that ingestion of dairy products results in exposure to D-galactose in concentrations metabolized primarily via the Leloir pathway with the potential to (i) promote anabolic signaling via maintenance of growth factor (e.g., insulin-like growth factor 1 [IGF-1]) receptor mature glycosylation patterns; and (ii) provide extracellular (liver glycogen) and intracellular substrates for short (muscle glycolysis) and long-term (muscle glycogen, intramyocellular lipids) energy availability. Additionally, D-galactose might optimize the metabolic function of skeletal muscles by increasing mitochondrial content and stimulating glucose and fatty acid utilization. The proposed potential of D-galactose to promote the accretion of SMM is discussed in the context of its therapeutic potential in sarcopenia.

A meta-analysis of the effect of probiotic administration on age-related sarcopenia

Global increase in the prevalence of age-related diseases, such as sarcopenia, highlights the need of recognizing agents that improve muscle health; however, the evidence synthesis on the impact of probiotic administration on sarcopenia is scarce. To summarize and evaluate findings regarding the effect of supplementation with probiotics on sarcopenia, this meta-analysis was conducted. Using databases, including PubMed, SCOPUS, ISI-Web of Science, and Cochrane Library, interventional studies were included if they investigate the effect of probiotic administration on at least one of the components of sarcopenia up to 6 October 2022. Risk of bias evaluation was conducted using the Cochrane quality assessment tool. The random-effects model which takes between-study variations into account was used to obtain the overall effect sizes. The STATA version 14.0 was used for statistical analyses. Overall, 17 studies were included. There was high certainty of evidence that probiotic supplementation has a beneficial effect on muscle mass (kg) (WMD: 0.55, 95% CI: 0.05, 1.05; I 2: 0.0%, p = .995), and muscle function (WMD: 0.13, 95% CI: 0.03, 0.23; I 2: 65.6%, p = .05). Moreover, administration of probiotics for more than 12 weeks significantly increased muscle strength (WMD: 1.16, 95% CI: 0.88, 1.44; I 2: 0.0%, p = .77). However, probiotic supplementation had no effect on anthropometric indices, including body mass index. Probiotic supplementation could improve muscle mass and muscle function in adults more than 55 years old. The beneficial effect of probiotics on muscle strength could appear after 12 weeks of supplementation.

Probiotic Regulation to Modulate Aging Gut and Brain Health: A Concise Review

The human gastrointestinal (GI) tract contains a diverse mixture of commensal and pathogenic microbes, forming the gut microbiome. These gut microbes and their potential to improve human health are a topic of great interest to the scientific community. Many intestinal and age-related complications are linked to dysbiosis of the gut microbiome, often associated with a weakened immune system. A decrease in beneficial microbes, generally, along with decreased microbial diversity in the gut, can, in many cases, result in disease, particularly in older individuals. Probiotics, which are ingestible beneficial microorganisms, have the potential to positively modulate the indigenous gut microbiota. There are two predominant and conventional classes of lactic acid bacterial probiotics, lactobacilli and bifidobacteria, which have been confirmed for their health benefits and role in preventing certain gut-related disorders. The proper use of probiotics and/or supplements, along with a consistently healthy lifestyle, is a promising holistic approach to maintaining or improving gut health and minimizing other age-linked disorders. There are many properties that bacterial probiotics possess, which may allow for these beneficial effects in the gut. For instance, probiotics have adhesion capacities (capability to stay in GI tract) that are effective in excluding pathogens, while other probiotics have the potential to stimulate or modulate the intestinal immune system by regulating genes that reside within and outside of the gut environment. This review discussed the possible underlying mechanics of probiotics, evidence of probiotic-based mitigation of age-related disease, and the role of probiotics in modulating gut health and, in turn, maintaining brain health.

Antioxidative potential of Lactobacillus sp. in ameliorating D-galactose-induced aging

Aging is a progressive, unalterable physiological degradation process of living organisms, which leads to deterioration of biological function and eventually to senescence. The most prevalent factor responsible for aging is the accumulation of damages resulting from oxidative stress and dysbiosis. D-galactose-induced aging has become a hot topic, and extensive research is being conducted in this area. Published literature has reported that the continuous administration of D-galactose leads to the deterioration of motor and cognitive skills, resembling symptoms of aging. Hence, this procedure is employed as a model for accelerated aging. This review aims to emphasize the effect of D-galactose on various bodily organs and underline the role of the Lactobacillus sp. in the aging process, along with its anti-oxidative potential. A critical consideration to the literature describing animal models that have used the Lactobacillus sp. in amending D-galactose-induced aging is also given. KEY POINTS: • D-Galactose induces the aging process via decreasing the respiratory chain enzyme activity as well as ATP synthesis, mitochondrial dysfunction, and increased ROS production. • D-Galactose induced aging primarily affects the brain, heart, lung, liver, kidney, and skin. • The anti-oxidative potential of Lactobacillus sp. in improving D-galactose-induced aging in animal models via direct feeding and feeding of Lactobacillus-fermented food.

Genomic Analysis of Limosilactobacillus fermentum ATCC 23271, a Potential Probiotic Strain with Anti-Candida Activity

Limosilactobacillus fermentum (ATCC 23271) was originally isolated from the human intestine and has displayed antimicrobial activity, primarily against Candida species. Complete genome sequencing and comparative analyses were performed to elucidate the genetic basis underlying its probiotic potential. The ATCC 23271 genome was found to contain 2,193,335 bp, with 2123 protein-coding sequences. Phylogenetic analysis revealed that the ATCC 23271 strain shares 941 gene clusters with six other probiotic strains of L. fermentum. Putative genes known to confer probiotic properties have been identified in the genome, including genes related to adhesion, tolerance to acidic pH and bile salts, tolerance to oxidative stress, and metabolism and transport of sugars and other compounds. A search for bacteriocin genes revealed a sequence 48% similar to that of enterolysin A, a protein from Enterococcus faecalis. However, in vitro assays confirmed that the strain has inhibitory activity on the growth of Candida species and also interferes with their adhesion to HeLa cells. In silico analyses demonstrated a high probability of the protein with antimicrobial activity. Our data reveal the genome features of L. fermentum ATCC 23271, which may provide insight into its future use given the functional benefits, especially against Candida infections.

Bacillus subtilis-Based Probiotic Improves Skeletal Health and Immunity in Broiler Chickens Exposed to Heat Stress

Simple Summary

High ambient temperature is a major environmental stressor affecting the physiological and behavioral status of animals, increasing stress susceptibility and immunosuppression, and consequently increasing intestinal permeability (leaky gut) and related neuroinflammation. Probiotics, as well as prebiotics and synbiotics, have been used to prevent or decrease stress-associated detrimental effects on physiological and behavioral homeostasis in humans and various animals. The current data indicate that a dietary probiotic supplement, Bacillus subtilis, reduces heat stress-induced abnormal behaviors and negative effects on skeletal health in broilers through a variety of cellular responses, regulating the functioning of the microbiota–gut–brain axis and/or microbiota-modulated immunity during bone remodeling under thermoneutral and heat-stressed conditions.

Abstract

The elevation of ambient temperature beyond the thermoneutral zone leads to heat stress, which is a growing health and welfare issue for homeothermic animals aiming to maintain relatively constant reproducibility and survivability. Particularly, global warming over the past decades has resulted in more hot days with more intense, frequent, and long-lasting heat waves, resulting in a global surge in animals suffering from heat stress. Heat stress causes pathophysiological changes in animals, increasing stress sensitivity and immunosuppression, consequently leading to increased intestinal permeability (leaky gut) and related neuroinflammation. Probiotics, as well as prebiotics and synbiotics, have been used to prevent or reduce stress-induced negative effects on physiological and behavioral homeostasis in humans and various animals. The current data indicate dietary supplementation with a Bacillus subtilis-based probiotic has similar functions in poultry. This review highlights the recent findings on the effects of the probiotic Bacillus subtilis on skeletal health of broiler chickens exposed to heat stress. It provides insights to aid in the development of practical strategies for improving health and performance in poultry.

Ginkgolide B monotherapy reverses osteoporosis by regulating oxidative stress-mediated bone homeostasis

Osteoporosis is characterized by reductions in bone mass, which could be attributed to the dysregulation of bone homeostasis, such as the loss of balance between bone-resorbing osteoclasts and bone-forming osteoblasts. Elevated levels of oxidative stress increase bone resorption by promoting osteoclastogenesis and inhibiting the osteogenesis. Ginkgolide B (GB), a small natural molecule from Ginkgo biloba, has been reported to possess pharmacological activities by regulating reactive oxygen species (ROS) in aging-related degenerative diseases. Herein, we assessed the therapeutic effects of GB on the bone phenotypes of mice with osteoporosis induced by (I) aging, (II) ovariectomy, and (III) glucocorticoids. In all three animal models, oral gavage of GB significantly improved bone mass consistent with the increase in the OPG-to-RANKL ratio. In the in vitro experiments, GB promoted osteogenesis in aged mesenchymal stem cells (MSCs) and repressed osteoclastogenesis in aged macrophages by reducing ROS. The serum protein profile in GB-treated aged mice revealed moderate rejuvenating effects; signaling pathways associated with ROS were also regulated. The anabolic and anti-catabolic effects of GB were illustrated by the reduction in ROS. Our results indicate that GB is effective in treating osteoporosis. The use of GB in patients with osteoporosis is worthy of further clinical investigation.

Young at Gut-Turning Back the Clock with the Gut Microbiome

Over the past century, we have witnessed an increase in life-expectancy due to public health measures; however, we have also seen an increase in susceptibility to chronic disease and frailty. Microbiome dysfunction may be linked to many of the conditions that increase in prevalence with age, including type 2 diabetes, cardiovascular disease, Alzheimer's disease, and cancer, suggesting the need for further research on these connections. Moreover, because both non-modifiable (e.g., age, sex, genetics) and environmental (e.g., diet, infection) factors can influence the microbiome, there are vast opportunities for the use of interventions related to the microbiome to promote lifespan and healthspan in aging populations. To understand the mechanisms mediating many of the interventions discussed in this review, we also provide an overview of the gut microbiome's relationships with the immune system, aging, and the brain. Importantly, we explore how inflammageing (low-grade chronic inflammation that often develops with age), systemic inflammation, and senescent cells may arise from and relate to the gut microbiome. Furthermore, we explore in detail the complex gut-brain axis and the evidence surrounding how gut dysbiosis may be implicated in several age-associated neurodegenerative diseases. We also examine current research on potential interventions for healthspan and lifespan as they relate to the changes taking place in the microbiome during aging; and we begin to explore how the reduction in senescent cells and senescence-associated secretory phenotype (SASP) interplay with the microbiome during the aging process and highlight avenues for further research in this area.

Gut dysbiosis and age-related neurological diseases; an innovative approach for therapeutic interventions

The gut microbiota is a complex ecosystem of bacteria, fungi, and viruses that acts as a critical regulator in microbial, metabolic, and immune responses in the host organism. Imbalances in the gut microbiota, termed "dysbiosis," often induce aberrant immune responses, which in turn disrupt the local and systemic homeostasis of the host. Emerging evidence has highlighted the importance of gut microbiota in intestinal diseases, and more recently, in age-related central nervous systems diseases, for example, stroke and Alzheimer's disease. It is now generally recognized that gut microbiota significantly influences host behaviors and modulates the interaction between microbiota, gut, and brain, via the "microbiota-gut-brain axis." Several approaches have been utilized to reduce age-related dysbiosis in experimental models and in clinical studies. These include strategies to manipulate the microbiome via fecal microbiota transplantation, administration of prebiotics and probiotics, and dietary interventions. In this review, we explore both clinical and preclinical therapies for treating age-related dysbiosis.