Search Results (51)

The oral cavity harbors one of the most diverse microbial ecosystems in the human body, second only to the gut. Periodontitis, a chronic inflammatory disease arising from oral microbiota dysbiosis, has been increasingly associated with systemic disorders such as diabetes mellitus, atherosclerosis, rheumatoid arthritis, inflammatory bowel disease, and neurodegenerative conditions. Although hematogenous dissemination of oral pathogens and inflammatory mediators has long been proposed as a mechanistic link, emerging evidence identifies the oral–gut axis as a novel bidirectional pathway. Swallowed oral pathobionts, such as Porphyromonas gingivalis and Fusobacterium nucleatum, can colonize the gut, disrupt the intestinal barrier, and induce dysbiosis, immune imbalance, and metabolic alterations that aggravate systemic inflammation and disease progression. In contrast, gut dysbiosis, especially in obesity or high-fat-diet models, can exacerbate periodontal tissue destruction through hyperuricemia, altered bone metabolism, and Th17/Treg immune imbalance. Experimental and clinical studies further support this reciprocal relationship, implicating microbial, metabolic, and immune crosstalk in both oral and systemic pathology. Understanding this oral–gut–systemic axis offers a paradigm shift in diagnostics and therapeutics, focusing on precision interventions such as microbiome modulation, probiotics, and integrated oral care to mitigate systemic inflammatory burden and improve overall health outcomes. Full article

Introduction: The work presented here is part of our study series aimed at investigating the countermeasure effectiveness of apigenin (AP) against both early and late effects of heavy silicon (²⁸Si) on the same cohort of exposed male C57BL/6 mice. We previously reported the countermeasure of AP against ²⁸Si-induced early effects of ²⁸Si ions. This section focuses on the protective effects of AP on late effects, specifically on the induction of acute lymphoma/lymphoblastic leukemia. Method: Mice received a diet containing 20 mg/kg body weight of AP for five days before and after total-body irradiation with either 0 or 0.5 Gy of 260 MeV ²⁸Si ions. They were divided into four groups based on AP intake and irradiation status. At one-week after irradiation, six mice from each group were euthanized to assess AP’s effectiveness against early inflammation (in the bone marrow and gut tissues) and gut dysbiosis. The remaining mice were monitored until approximately 770 days of age. Incidence rates were analyzed using Chi-Square tests, while survival data were evaluated with Kaplan–Meier plots and log-rank tests, setting significance at p ≤ 0.05. Results: At 770 days, survival rates were 37% for ²⁸Si-exposed mice and 63% for those consuming AP, despite irradiation. There was a 2.57-fold increase in acute lymphoma/lymphoblastic leukemia incidence among ²⁸Si-exposed mice not receiving AP compared to controls and AP-fed mice. Together with our previous report on the countermeasure activity of AP against early effects, these findings suggest that the gut–bone marrow axis plays an important role in ²⁸Si-induced acute lymphoma/lymphoblastic leukemia. Conclusion: Our findings demonstrate that AP is an effective means of tackling the challenges posed by space radiation, and it has the potential to revolutionize protection in this critical area. Full article

The interaction between the gut microbiota and the skeletal system has evolved into a new research focus. Studies underscore the role of bioactive metabolites in sustaining systemic balance via the “gut microbiota–endocrine–skeleton” axis, where they modulate metabolic processes and organ morphology through intracellular signaling. A key bidirectional relationship exists with the gut: shifts in gut microbiota affect host metabolism and subsequent metabolite profiles, while these metabolites can, in turn, reshape the intestinal microenvironment. This review explores how short-chain fatty acids (SCFAs), estrogen, and vitamin D modulate osteoporosis via the gut–bone axis. It synthesizes evidence of their signaling pathways and metabolic roles, identifies research gaps from recent clinical studies, and evaluates gut microbiota-targeted therapeutic strategies for potential clinical translation. Full article

Testosterone is a hormone that plays a crucial role in men, maintaining muscle mass and bone density and regulating sexual function. This hormone is associated with the inhibition of obesity and the prevention of obesity-related diseases, such as type 2 diabetes, impaired glucose tolerance, dyslipidemia, hypertension, coronary artery disease, and non-alcoholic fatty liver disease. Obesity has a complex effect on testosterone production and metabolism. Chronic inflammation and hormones associated with obesity cause dysfunction of the hypothalamic-pituitary-gonadal axis, leading to reduced testosterone production. Studies have demonstrated that blood testosterone levels decrease in obese men, suggesting a reciprocal interaction between decreased testosterone and obesity. Additionally, decreased testosterone levels are closely associated with aging. The natural decline in testosterone levels with age can lead to visceral obesity, thus increasing the risk of type 2 diabetes and other chronic metabolic diseases. In many countries, the population is aging, and the importance of testosterone replacement therapy (TRT) for aging men with low testosterone is increasing. Recent studies have expanded our understanding of TRT, highlighting its potential benefits in obese individuals, its interaction with gut microbiota, and the influence of racial differences and genetic polymorphisms on treatment efficacy. This review provides a comprehensive overview of the physiological mechanisms linking obesity and testosterone, current therapeutic approaches including TRT, and emerging research directions that may inform personalized treatment strategies. Full article

Osteoporosis is a progressive bone disorder characterized by decreased bone mineral density and structural deterioration, leading to increased fracture risk. Conventional treatments, although effective, are limited by adverse effects and low long-term adherence. In recent years, polyphenols, plant-derived bioactive compounds, have emerged as promising candidates for bone health promotion due to their antioxidant, anti-inflammatory, and osteo-regulatory properties. This review synthesizes the current preclinical and clinical evidence on the potential of polyphenols, including quercetin, resveratrol, curcumin, isoflavones, and epigallocatechin gallate, to modulate bone metabolism and prevent or mitigate osteoporosis. Mechanistically, polyphenols enhance osteoblastogenesis, inhibit osteoclast differentiation, regulate the RANKL/OPG axis, and activate key osteogenic pathways such as Wnt/β-catenin and MAPKs. Additionally, their estrogen-like activity and ability to modulate gut microbiota offer further therapeutic potential. Preclinical models consistently demonstrate improvements in bone mass, architecture, and turnover markers, while clinical trials, although limited, support their role in preserving bone density, particularly in postmenopausal women. Despite promising outcomes, variability in bioavailability, dosage, and study design limits current translational application. Further large-scale clinical studies and standardized formulations are needed. Polyphenols represent a compelling adjunct or alternative approach in the integrated management of osteoporosis. Full article

Pet humanization, particularly in dogs and cats, has transformed animal healthcare and highlighted the importance of nutrition in promoting human–pet social interaction, pet psychophysical well-being and, possibly, longevity. Nutraceuticals, such as omega-3 fatty acids, prebiotics, probiotics, plant extracts and dietary supplements, are endowed with antioxidant, anti-inflammatory, immune-modulating, cognitive-enhancing and gut-microbiota balancing properties. These effects have been shown to contribute to the possible prevention and management of bone and skin diseases, as well as gastrointestinal and behavioral disturbs. Moreover, the human–animal bond has been shown to play a pivotal role in reducing stress, improving sociability, and modulating pets’ emotional and physiological states. Evidence also suggests that nutrition and social interactions can influence the gut–brain axis, impacting the behavior, cognition, and resilience to stress-related disorders. Besides underlining the value of nutraceutical integration into pet nutrition strategies and offering a comprehensive, evidence-based perspective on their potential in improving animal welfare, literature reports about drawbacks of the use/misuse of such substances have been reported. Full article

Bone immunity represents a dynamic interface where skeletal homeostasis intersects with systemic immune regulation. We synthesize emerging paradigms by contrasting two functionally distinct microenvironments: the marrow cavity, a hematopoietic and immune cell reservoir, and cancellous bone, a metabolically active hub orchestrating osteoimmune interactions. The marrow cavity not only generates innate and adaptive immune cells but also preserves long-term immune memory through stromal-derived chemokines and survival factors, while cancellous bone regulates bone remodeling via macrophage-osteoclast crosstalk and cytokine gradients. Breakthroughs in lymphatic vasculature identification challenge traditional views, revealing cortical and lymphatic networks in cancellous bone that mediate immune surveillance and pathological processes such as cancer metastasis. Central to bone immunity is the neuro–immune–endocrine axis, where sympathetic and parasympathetic signaling bidirectionally modulate osteoclastogenesis and macrophage polarization. Gut microbiota-derived metabolites, including short-chain fatty acids and polyamines, reshape bone immunity through epigenetic and receptor-mediated pathways, bridging systemic metabolism with local immune responses. In disease contexts, dysregulated immune dynamics drive osteoporosis via RANKL/IL-17 hyperactivity and promote leukemic evasion through microenvironmental immunosuppression. We further propose the “brain–gut–bone axis” as a systemic regulatory framework, wherein vagus nerve-mediated gut signaling enhances osteogenic pathways, while leptin and adipokine circuits link marrow adiposity to inflammatory bone loss. These insights redefine bone as a multidimensional immunometabolic organ, integrating neural, endocrine, and microbial inputs to maintain homeostasis. By elucidating the mechanisms of immune-driven bone pathologies, this work highlights therapeutic opportunities through biomaterial-mediated immunomodulation and microbiota-targeted interventions, paving the way for next-generation treatments in osteoimmune disorders. Full article

Inflammatory bowel disease (IBD) demonstrates chronic relapsing inflammation extending beyond adaptive immunity dysfunction. “Trained immunity”—the reprogramming of innate immune memory in myeloid cells and hematopoietic progenitors—maintains intestinal inflammation; however, the mechanism by which gut microbiome orchestration determines protective versus pathological outcomes remains unclear. Microbial metabolites demonstrate context-dependent dual effects along the gut–bone marrow axis. Short-chain fatty acids typically induce tolerogenic immune memory, whereas metabolites like succinate and polyamines exhibit dual roles: promoting inflammation in certain contexts while enhancing barrier integrity in others, influenced by cell-specific receptors and microenvironmental factors. Interventions include precision probiotics and postbiotics delivering specific metabolites, fecal microbiota transplantation addressing dysbiotic trained immunity, targeted metabolite supplementation, and pharmacologic reprogramming of pathological myeloid training states. Patient stratification based on microbiome composition and host genetics enhances therapeutic precision. Future research requires integration of non-coding RNAs regulating trained immunity, microbiome–immune–neuronal axis interactions, and host genetic variants modulating microbiome–immunity crosstalk. Priorities include developing companion diagnostics, establishing regulatory frameworks for microbiome therapeutics, and defining mechanistic switches for personalized interventions. Full article

Bone health is critically influenced by the oral and gut microbiota, which are among the largest microbial reservoirs in the human body. These microbiota play essential roles in maintaining bone mass through immune modulation, metabolite production, and nutrient resorption. Recent observations have underscored that extracellular vesicles (EVs) derived from oral and gut microbiota may circulate to the brain and bone marrow, suggesting their integral roles in the gut–brain–bone axis and oral–brain–bone axis. This review outlines the current research status of bacterial extracellular vesicles (BEVs), including their biogenesis, classification, structural features, and cargo composition, with emphasis on factors influencing cargo heterogeneity and the consequences of cellular uptake and presentation. Oral-microbiota-derived BEVs and their cargo associated with bone health are highlighted, along with recent evidence linking BEVs to systemic dis-eases and the potential integration into the oral–gut–bone axis. Preclinical animal studies on BEV dosage, routes of administration, and disease models are summarized, together with the limitations of current approaches and strategies for engineering BEVs. Finally, an overview of translational applications and future therapeutic prospects is provided, aiming to advance the understanding of BEVs as innovative tools for the treatment and prevention of bone-related diseases. Full article

Chronic stress induces mood disturbances, disrupts gut barrier function, and promotes low-grade systemic inflammation. This study assessed the therapeutic effects of atomoxetine (ATX), escitalopram (ESC), cannabidiol (CBD), and CBD-loaded lipid nanoparticles (CBD/LNP) in male rats exposed to repeated restraint stress. Stressed rats exhibited a 2.03-fold increase in interleukin-6 and a 1.89-fold increase in TNF-α, a 1.20-fold decrease in brain-derived neurotrophic factor, a 1.36-fold decrease in osteocalcin, accompanied by alterations in gut metabolites, particularly short-chain fatty acids (SCFAs; from 155.3 to 94.83 μmol/L), polyamines (from 273.6 to 192.4 μmol/L), and bile acids (BAs; from 21.19 to 14.53 μmol/L), compared with the control group. Protein analysis revealed gut barrier disruption and microglial/macrophage activation, accompanied by reduced synaptic plasticity. ATX improved gut permeability and reduced glial activation but did not restore osteocalcin. ESC provided neuroimmune benefits with limited and BA gut restoration and modulated the gut–brain axis and improved anxiety-like behaviors, partly by altering gut microbiota and metabolites. CBD and CBD/LNP treatment restored intestinal barrier function, as indicated by intestinal permeability in the range of 1.15–1.61-fold. These treatments also normalized bile acids (1.0–1.38-fold) and osteocalcin (1.0–1.28-fold) and significantly reduced glial activation (0.63–1.12-fold) as opposed to the non-treated stressed group. All treatments were found to be effective in correcting SCFA and polyamine levels. Histological analysis confirmed that CBD/LNP, ATX, and ESC ameliorated tissue alterations. These findings highlight CBD/LNP as a promising intervention for stress-induced gut–brain–bone axis disruption, supporting its potential as a therapeutic alternative through modulation of microbiota-driven gut–brain communication in stress-associated disorders. Full article

Inter-organ communication plays a vital role in the pathogenesis of neurodegenerative diseases (ND), including Alzheimer’s disease (AD), Parkinson’s disease (PD), and Amyotrophic Lateral Sclerosis (ALS). Emerging research highlights the involvement of the gut–brain axis, immune system, and peripheral metabolic systems in modulating neuroinflammation, protein misfolding, and neuronal dysfunction by releasing cytokines, adipokines, growth factors, and other soluble factors, which in turn affect neuronal health and systemic inflammation. This review explores the complex bidirectional interactions between the brain and peripheral organs, including the gut, adipose tissue, liver, muscle, bone and immune system. Notably, the gut microbiome’s role in neurodegenerative diseases through the gut–brain axis, the impact of adipose tissue in inflammation and metabolic regulation, and the muscle–brain axis with its neuroprotective myokines are also discussed. Additionally, we examine the neuro-immune axis, which mediates inflammatory responses and exacerbates neurodegeneration, and liver–brain axis that is implicated in regulating neuroinflammation and promoting disease progression. Dysregulation of inter-organ pathways contributes to the systemic manifestations of neurodegenerative diseases, offering insights into both potential biomarkers and therapeutic targets, and, in turn, promising strategies for preventing, diagnosing, and treating neurodegenerative diseases. Full article

Background/Objectives: Fructooligosaccharides (FOS) and dried tart cherry (TC) are examples of simple and complex (i.e., within a food matrix) prebiotics that have demonstrated promising osteoprotective activity. In this study, we examined how dietary supplementation with TC or FOS shapes the gut-bone axis to promote bone accrual in young adult mice, and the role of the gut microbiota in mediating these responses. Methods: Studies were performed using 10-wk-old female C57BL/6 mice (n = 10–12/group) fed a control diet or control diet supplemented with 10% TC or FOS for 10 wks alone or in combination with an antibiotic/anti-fungal cocktail to suppress the gut microbiota. The bone phenotype was characterized by dual-energy X-ray absorptiometry, micro-computed tomography and static and dynamic bone histomorphometry. The gut-microbiota was profiled and short chain fatty acids (SCFA) were assessed based on 16S rRNA profiling and gas chromatographic techniques, respectively. Results: FOS and TC enhanced bone structure, with FOS yielding more pronounced benefits across cortical and trabecular compartments. These skeletal improvements with FOS occurred in the absence of systemic changes in bone turnover markers but were accompanied by increases in local bone formation, osteoblast and osteocyte numbers, and bone mineralization in the femur. Both diets altered gut microbiota composition and increased fecal concentrations of the most abundant SCFAs (i.e., acetate, propionate and butyrate), but the response was greater with FOS. Suppression of the gut microbiota and fecal SCFAs with the antibiotic/anti-fungal cocktail inhibited the effects of FOS and TC on cortical bone, but induced unexpected improvements in the trabecular bone. Conclusions: These findings demonstrate differential effects of simple and complex prebiotics on the gut-bone axis in young adult female mice and support a role for SCFA in the cortical bone response, but not in the trabecular bone response with this model of gut microbiota suppression. Full article

Acute myeloid leukemia (AML), the most common acute leukemia among adults, poses significant therapeutic challenges due to diagnostic limitations and the frequent development of treatment resistance. While genomics-based approaches have advanced, DNA aberrations do not always reflect the expression levels of genes and proteins, which are more tightly connected to disease phenotypes. Recently, the role of the gut microbiota in AML has gained increasing attention. AML patients often exhibit gut microbiota dysbiosis, which is linked to disease progression and heightened infection risk. Mounting evidence indicates that gut microbiota metabolism influences hematopoiesis and immune function via the “gut-bone marrow axis,” with microbiota composition and diversity significantly affecting treatment outcomes and prognosis. High-throughput sequencing and metabolomics have identified correlations between gut microbiota composition and its metabolic products with AML clinical characteristics, paving the way for new biomarkers in diagnosis and prognosis. Additionally, treatments such as fecal microbiota transplantation (FMT) show promise in enhancing chemotherapy efficacy and improving patient outcomes. This review highlights recent advances in understanding the role of the gut microbiota in AML and explores new perspectives for its diagnosis and treatment. Full article

As a highly disabling chronic inflammatory disease, rheumatoid arthritis (RA) necessitates novel interventions. Liupao tea is a traditional Chinese dark tea known for its favorable anti-inflammatory properties. This study aims to elucidate the active ingredients and action mechanisms underlying the therapeutic effects of Liupao tea extract (LPTE) in RA. LPTE was preliminarily characterized by LC-MS technology. Network pharmacology and molecular docking predicted anti-RA compounds, targets, and pathways, with key compounds identified using chemical standards. The effect of LPTE on the collagen-induced arthritis mouse model was evaluated through serum biochemical analysis, micro-CT imaging, and histopathological analyses. Integrated serum metabolomics, 16S rRNA sequencing, MetOrigin analysis, SCFA metabolomics, and quantitative real-time PCR elucidated gut–joint axis mechanisms. LPTE effectively attenuated RA symptoms by reducing bone destruction and joint inflammation. Notably, LPTE reshaped gut microbiota by enriching key families such as Monoglobaceae, Eggerthellaceae, and Desulfovibrionaceae, thereby promoting SCFA production. Increased SCFA levels enhanced intestinal barrier integrity and exerted joint-protective and anti-inflammatory effects by upregulating tight junction proteins and activating SCFA receptors. LPTE also modulated arachidonic acid metabolism by affecting key genes such as Alox5, Ptgs2, and Cbr1. These effects collectively reduced the levels of pro-inflammatory cytokines and increased the expression of anti-inflammatory cytokines in joints. Additionally, quercetin, luteolin, ellagic acid, and kaempferol were identified as major anti-RA bioactive compounds in LPTE. Taken together, this study provides preliminary evidence that LPTE mitigates RA by regulating the gut–joint axis mediated via fatty acid metabolism. Full article

Osteoporosis is a systemic bone disorder characterized by decreased bone mass and deteriorated microarchitecture, leading to an increased risk of fractures. Recent studies have revealed that its pathogenesis involves complex biological processes beyond bone remodeling, including oxidative stress, chronic inflammation, cellular senescence, osteoimmunology, gut microbiota alterations, and epigenetic modifications. Oxidative stress disrupts bone homeostasis by promoting excessive free radical production and osteoclast activity. Chronic inflammation and the accumulation of senescent cells impair skeletal repair mechanisms. Advances in osteoimmunology have highlighted the critical role of immune–bone crosstalk in regulating bone resorption and formation. Moreover, the gut–bone axis, mediated by microbial metabolites, influences bone metabolism through immune and endocrine pathways. Epigenetic changes, such as DNA methylation and histone modification, contribute to gene–environment interactions, affecting disease progression. Multi-omics approaches (genomics, proteomics, and metabolomics) systematically identify molecular networks and comorbid links with diabetes/cardiovascular diseases, revealing pathological feedback loops that exacerbate bone loss. In conclusion, osteoporosis pathogenesis extends beyond bone remodeling to encompass systemic inflammation, immunometabolic dysregulation, and gut microbiota–host interactions. Future research should focus on integrating multi-omics biomarkers with targeted therapies to advance precision medicine strategies for osteoporosis prevention and treatment. Full article