Gut Microbiota Is Involved in Alcohol-Induced Osteoporosis in Young and Old Rats Through Immune Regulation

Relationships among osteoporosis, redox homeostasis, and alcohol addiction: Importance of the brain-bone axis

Overabundance of reactive oxygen species (oxidative distress) leads to redox homeostasis disturbance and is associated with many pathological conditions. Accumulating evidence suggests that oxidative distress may contribute to osteoporosis. This review thoroughly outlines the relationships among osteoporosis, redox homeostasis, and alcohol addiction, since these relations are not sufficiently known and subsequently summarized. The brain-bone axis plays a crucial role in alcohol-induced damage to the nervous and skeletal systems. Alterations in the nervous system can lead to osteoporosis because the central nervous system is involved in bone remodeling through various neural pathways. Conversely, as an endocrine organ, bone secretes a number of bone-derived factors (osteokines), which can influence brain function and behavior. As a result, osteoporosis is more common in individuals with neurological disorders, and sudden neurological events can rapidly increase the risk of osteoporosis. Excessive alcohol consumption is linked to many neurological complications, as well as osteoporosis, which are manifested by disrupted redox homeostasis, inflammation, neurodegeneration, inhibition of neurogenesis, decreased bone mineral density, impaired bone microarchitecture, altered mineral homeostasis, raising fracture risk, hormonal dysregulation, and altered gut microbiota composition. Compared to men, alcohol dependence has more negative consequences for women, including an increased risk of liver, cardiovascular, metabolic, mental disorders, and breast cancer. Abstinence has been demonstrated to improve bone and brain health in alcohol addiction. The discovery of the brain-bone axis may lead to the development of new therapeutic approaches for alcohol and other substance addictions. Further research is needed in this direction, as many questions remain unanswered.

Alcohol-induced bone loss driven by dysregulated spatial distribution of gut microbiota and PGD2-IL17 pathway-mediated osteoclast activation

Introduction

Alcohol-induced damage to bone microstructure leads to alcoholic osteoporosis (AOP). While prior studies have demonstrated alcohol's negative impact on bone density, the mechanisms by which alcohol induces osteoporosis through immune pathways, gut microbiota dysbiosis, and metabolic alterations remain insufficiently characterized. Given that alcohol is primarily absorbed in the upper gastrointestinal tract, in this research, we aimed to elucidate the role of spatial distribution disorders in gut microbiota and metabolites in the pathogenesis of alcohol-induced osteoporosis. We further sought to evaluate the potential of microbiota supplementation and targeted immunosuppressants as therapeutic strategies for related bone diseases.

Methods

An osteoporosis model using mice was established using alcohol drinking bottles, and bone loss was validated using micro-computed tomography. Segmented intestinal samples and fecal samples were analyzed using 16S rRNA sequencing and metabolomics. Mechanistic studies were conducted by supplementing R. intestinalis, prostaglandin D2 (PGD2), and its specific immune inhibitor, ramatroban. Analytical methods included tartrate-resistant acid phosphatase staining, flow cytometry, and enzyme-linked immunosorbent assay.

Results

Alcohol disrupted the spatial complexity of intestinal segments and fecal microbiota in mice, causing metabolic dysregulation and ultimately leading to elevated PGD2 levels. This, in turn, triggered Th17/Treg immune imbalance and osteoclast activation, resulting in bone loss. Supplementation with the probiotic R. intestinalis or inhibition of PGD2 significantly improved bone density and alleviate inflammation.

Conclusion

This study demonstrates that alcohol-induced elevation of PGD2 is a key pathogenic factor in AOP. PGD2 accelerates bone loss by promoting osteoclast formation through the activation of Th17 cells. Furthermore, this study highlights the importance of investigating the spatial distribution of gut microbiota and metabolites, providing potential targets and novel strategies for the precise treatment of AOP and other diseases associated with external stimuli.

Association between dietary inflammatory index score and cardiovascular-kidney-metabolic syndrome: a cross-sectional study based on NHANES

Background

Cardiovascular-kidney-metabolic (CKM) syndrome affects 25% of US adults, with chronic inflammation as a key pathophysiological mechanism. While the inflammatory basis of CKM syndrome is established, associations of the energy-adjusted dietary inflammatory index (E-DII) with CKM syndrome remain unexplored in the general population.

Methods

Using data from 7,110 participants in the National Health and Nutrition Examination Survey (2007-2018), we examined the association between E-DII (calculated from dietary recall data) and CKM syndrome (defined as co-occurrence of cardiometabolic syndrome and chronic kidney disease). Multiple logistic regression, restricted cubic spline analyses, weighted quantile sum regression, and quantile g-computation were performed to assess associations and dietary component contributions.

Results

Higher E-DII scores correlated with increased CKM syndrome prevalence (OR: 1.22, 95% CI: 1.09-1.37). The relationship exhibited linearity (p for nonlinearity = 0.464). Stratified analyses across demographic and socioeconomic subgroups revealed consistent associations. Component analyses identified alcohol as the dietary factor with the strongest association with CKM syndrome.

Conclusion

The findings demonstrate a significant association between dietary inflammatory potential and CKM syndrome, with alcohol consumption emerging as a key modifiable factor. These results provide evidence-based insights for developing targeted dietary interventions in CKM syndrome prevention.

Sex differences in alcohol inhibits bone formation and promotes bone resorption in young male and female rats by altering intestinal flora, metabolites, and bone microenvironment

BACKGROUND

Long-term alcohol intake has toxic effects on osteoblasts and osteoclasts, resulting in decreased bone density, which directly disrupts the composition of the gut microbiota and affects bone metabolism and immune activity. The effects of alcohol on the bones may be closely related to sex. This study investigated the effects of long-term alcohol consumption on bone status in different sexes by examining the gut microbiota, bone metabolism, and immune activity.

METHODS

Young male and female rats were administered a Bio-Serv liquid diet containing 5% alcohol. The effects of alcohol metabolism capacity, bone morphology, bone formation, bone resorption, bone marrow immune activity, gut microbiota, and metabolite differences were analyzed in male and female rats using hematoxylin and eosin staining, micro-computed tomography, enzyme-linked immunosorbent assay, western blotting, 16S rRNA sequencing, and untargeted metabolomics.

RESULTS

Chronic alcohol consumption resulted in excessive osteoclast activation and decreased bone mineral density. Furthermore, alcohol reduced bone metabolism and formation while increasing bone resorption. Bone loss was significantly more severe in female rats than in male rats, indicating that the effects of alcohol on rat bones are related to sex. Chronic alcohol consumption also led to polarization of bone marrow immunoreactivity toward the M1 phenotype. In addition, chronic alcohol consumption affected the composition of gut microbiota, reduced the richness and diversity of intestinal microbiota, and decreased the ratio of Firmicutes/Bacteroidetes. Long-term alcohol consumption also affected fecal metabolites, and 754 differentially expressed metabolites were identified.

CONCLUSIONS

Chronic alcohol consumption increased bone resorption, inhibited bone formation, and affected bone marrow immunoreactivity in young male and female rats. Alcohol can also affect gut microbiota composition and fecal metabolism. Female rats were more susceptible to alcohol, possibly because young female rats have a lower alcohol metabolism, immunomodulatory capacity, and gut microbiota diversity than young male rats.

A calcium-loaded complex based on Antarctic krill protein and supplemented with pectin promotes calcium absorption and bone health

Calcium participates in many biological functions, and calcium deficiency can lead to gut microbiota imbalance, increasing the risk of osteoporosis. This research aimed to assess the in vivo effects of a novel calcium-loaded complex (P + Ca + HMP) based on Antarctic krill protein and supplemented with pectin, using a calcium-deficient mouse model. The results revealed that chronic calcium deprivation resulted in decreased calcium absorption and degradation of trabecular microarchitecture. The P + Ca + HMP complex significantly increased the calcium retention rate to 89.87 ± 0.66 % and enhanced the maximum load of the femur to 9.28 ± 1.12 N, which were significantly higher than those of the low-calcium group, indicating that the complex could effectively enhance the biomechanical properties of bone. Additionally, the P + Ca + HMP complex also significantly increased the continuity, integrity and thickness of the trabecular network, improving bone microarchitecture. Furthermore, after the P + Ca + HMP complex intervention, beneficial bacteria such as Lactobacillus and Blautia increased and were significantly positively associated with improved calcium absorption and bone synthesis. In conclusion, the P + Ca + HMP complex achieved effective calcium delivery and exhibited significant efficacy in regulating the intestinal environment, promoting calcium absorption, and bone health, demonstrating potential as a novel calcium supplement for preventing calcium deficiency.

Therapeutic effects of Isaria felina on postmenopausal osteoporosis: modulation of gut microbiota, metabolites, and immune responses

Background

The intricate relationship between human health and gut microecology has emerged as a central theme in contemporary medical research. Postmenopausal osteoporosis, primarily driven by estrogen deficiency, remains a major health concern. Traditional Chinese herbal medicines have attracted significant interest for their promising role in osteoporosis treatment.

Methods

The effects of Isaria felina, derived from Cordyceps sinensis, on postmenopausal osteoporosis in rats are the focus of this study. Adult female Sprague-Dawley rats were categorized into control, postmenopausal osteoporosis (OVX), and Isaria felina-treated (IF+OVX) groups. Following a 12-week treatment period, various analyses, including micro-CT, histological assessments, 16S rDNA sequencing, untargeted metabolomics, flow cytometry, and ELISA, were performed.

Results

Micro-CT and histological assessments indicated significant improvements in bone loss and obesity control in OVX rats treated with Isaria felina. 16S rDNA sequencing revealed that Isaria felina corrected gut microbiota dysbiosis, particularly in the Bacteroides and Ruminococcus genera. Untargeted metabolomics highlighted alterations in nucleotide and lipid metabolism. Flow cytometry and ELISA analyses demonstrated that Isaria felina modulated the Th17/Treg immune balance, resulting in reduced levels of inflammatory cytokines IL-17 and TNF-α.

Conclusions

These findings indicate that Isaria felina mitigates bone loss in postmenopausal osteoporosis through modulation of gut microbiota and immune responses, underscoring its potential as a therapeutic agent for osteoporosis treatment.

Role of Interleukins-8, -17 and -22 in Iraqi postmenopausal women with Osteoporosis

OBJECTIVES

Osteoporosis (OP) is a systemic skeletal disease characterized by low bone mineral density and deterioration of bone architecture, resulting in bone strength reduction and increased fracture susceptibility. Estrogen deficiency in post-menopausal women is possibly responsible for the instability between bone formation and resorption, which is managed by specific osteoclastogenic cytokines that may be leading to resorption. This study aims to estimation of the concentrations of interleukins -8, -17, -22, beside to certain parameters in blood serum and explained their roles in the development of osteoporosis pathogenicity in postmenopausal women.

MATERIALS AND METHODS

A case-control study included 108 Iraqi postmenopausal women participants their ages ranged between 45 and 70 years. All participants subjected to the DEXA scan, 58 samples were osteoporotic patients, whereas 50 were healthy controls. Blood samples collected from all participants in order to assess the levels of interleukins -8, -17, -22, CBC, CRP, RF, and ACPA.

RESULTS

The concentrations of IL-8, -17, -22, ESR, PLT, CRP, RF and ACPA exhibited a positive correlation with OP development. Conversely, WBC and HGB concentrations showed a negative association with osteoporosis.

CONCLUSION

A remarkable relationship was obtained between the values of IL-8, 17, -22, CRP, RF, ACPA, ESR, PLT and osteoporosis but in contrary with WBCs and HGB. IL-8, -17, and - 22 can be linked to specific inflammatory diseases associated with the postmenopausal period, may act as one of the main biomarkers for osteoporosis due to their ability to stimulate osteoclastogenesis and bone resorption, and may be considered potential prognostic factors for osteoporosis.

Gut microbiome and bone health: update on mechanisms, clinical correlations, and possible treatment strategies

The intestinal microbiome is increasingly regarded as a relevant modulator of the pathophysiology of several age-related conditions, including frailty, sarcopenia, and cognitive decline. Aging is in fact associated with alteration of the equilibrium between symbiotic bacteria and opportunistic pathogens, leading to dysbiosis. The microbiome is able to regulate intestinal permeability and systemic inflammation, has a central role in intestinal amino acid metabolism, and produces a large number of metabolites and byproducts, with either beneficial or detrimental consequences for the host physiology. Recent evidence, from both preclinical animal models and clinical studies, suggests that these microbiome-centered pathways could contribute to bone homeostasis, regulating the balance between osteoblast and osteoclast function. In this systematic review, we provide an overview of the mechanisms involved in the gut-bone axis, with a particular focus on microbiome function and microbiome-derived mediators including short-chain fatty acids. We also review the current evidence linking gut microbiota dysbiosis with osteopenia and osteoporosis, and the results of the intervention studies on pre-, pro-, or post-biotics targeting bone mineral density loss in both animal models and human beings, indicating knowledge gaps and highlighting possible avenues for future research.

Preparation, characterization, stability and replenishing calcium ability of Moringa oleifera leaf peptide-calcium chelates

Calcium deficiency has garnered significant attention as a global public health issue. A new generation of calcium supplements, peptide-calcium chelates, is expected to increase in market value. In this study, we produced MORP (MW < 1 kDa) from Moringa oleifera leaf protein via enzymatic hydrolysis for chelation with Ca2+ to produce MORP-Ca. SEM, EDS, FTIR and FS characterized the structure of MORP-Ca. The results indicate alterations in both the appearance and internal structure of MORP following calcium chelation. The functional groups of N-H, C-H, C-N, -C = O, -COO-, C-O, and -OH in MORP are involved in chelating Ca2+ to form MORP-Ca. In addition, MORP-Ca exhibits poor stability in the stomach; however, it demonstrates high stability in the intestine and under various temperature conditions. The results of the cellular experiments demonstrated that MORP-Ca is an effective promoter of calcium transport and absorption. MORP-Ca effectively increased bone mineral density and improved bone formation in animal studies. In addition, MORP-Ca supplementation improved the gut microbiota imbalance in rats fed a calcium-deficient diet, resulting in an increase in Firmicutes and a decrease in Actinobacteria. Thus, there is a connection between altered gastrointestinal flora and calcium absorption. LC-MS/MS and molecular docking analyses identified ARNEGRDL, RELIIGDR, YTPDYETK, YYTPDYETK, and IKFEFPAVDTL as key peptide sequences for the calcium-supplementing role of MORP (MW < 1 kDa). These results establish a theoretical foundation for the use of MORP-Ca as a calcium supplement or functional food.

From gut to bone: deciphering the impact of gut microbiota on osteoporosis pathogenesis and management

Osteoporosis (OP) is characterized by decreased bone mineral density (BMD) and increased fracture risk, poses a significant global health burden. Recent research has shed light on the bidirectional relationship between gut microbiota (GM) and bone health, presenting a novel avenue for understanding OP pathogenesis and developing targeted therapeutic interventions. This review provides a comprehensive overview of the GM-bone axis, exploring the impact of GM on OP development and management. We elucidate established risk factors and pathogenesis of OP, delve into the diversity and functional changes of GM in OP. Furthermore, we examine experimental evidence and clinical observations linking alterations in GM composition or function with variations in BMD and fracture risk. Mechanistic insights into microbial mediators of bone health, such as microbial metabolites and products, are discussed. Therapeutic implications, including GM-targeted interventions and dietary strategies, are also explored. Finally, we identify future research directions and challenges in translating these findings into clinical practice.

Altered gut microbe metabolites in patients with alcohol‑induced osteonecrosis of the femoral head: An integrated omics analysis

Excessive alcohol consumption is considered to be a major risk factor of alcohol-induced osteonecrosis of the femoral head (AONFH). The gut microbiota (GM) has been reported to aid in the regulation of human physiology and its composition can be altered by alcohol consumption. The aim of the present study was to improve the understanding of the GM and its metabolites in patients with AONFH. Metabolomic sequencing and 16S rDNA analysis of fecal samples were performed using liquid chromatography-mass spectrometry to characterize the GM of patients with AONFH and healthy normal controls (NCs). Metagenomic sequencing of fecal samples was performed to identify whether GM changes on the species level were associated with the expression of gut bacteria genes or their associated functions in patients with AONFH. The abundance of 58 genera was found to differ between the NC group and the AONFH group. Specifically, Klebsiella, Holdemanella, Citrobacter and Lentilactobacillus were significantly more abundant in the AONFH group compared with those in the NC group. Metagenomic sequencing demonstrated that the majority of the bacterial species that exhibited significantly different abundance in patients with AONFH belonged to the genus Pseudomonas. Fecal metabolomic analysis demonstrated that several metabolites were present at significantly different concentrations in the AONFH group compared with those in the NC group. These metabolites were products of vitamin B6 metabolism, retinol metabolism, pentose and glucuronate interconversions and glycerophospholipid metabolism. In addition, these changes in metabolite levels were observed to be associated with the altered abundance of specific bacterial species, such as Basidiobolus, Mortierella, Phanerochaete and Ceratobasidium. According to the results of the present study, a comprehensive landscape of the GM and metabolites in patients with AONFH was revealed, suggesting the existence of interplay between the gut microbiome and metabolome in AONFH pathogenesis.

Effect of sheep bone protein hydrolysate on promoting calcium absorption and enhancing bone quality in low-calcium diet fed rats

Calcium deficiency is prone to fractures, osteoporosis and other symptoms. In this study, sheep bone protein hydrolysates (SBPHs) were obtained by protease hydrolysis. A low-calcium-diet-induced calcium-deficiency rat model was established to investigate the effects of SBPHs on calcium absorption and intestinal flora composition. The results showed that an SBPHs + CaCl2 treatment significantly increased the bone calcium content, bone mineral density, trabecular bone volume, and trabecular thickness, and reduced trabecular separation, and changed the level of bone turnover markers (P < 0.05). Supplementation of SBPHs + CaCl2 can remarkably enhance the bone mechanical strength, and the microstructure of bone was improved, and the trabecular network was more continuous, complete, and thicker. Additionally, SBPHs + CaCl2 dietary increased the abundance of Firmicutes and reduced the abundance of Proteobacteria and Verrucomicrobiota, and promoted the production of short chain fatty acids. This study indicated that SBPHs promoted calcium absorption and could be applied to alleviate osteoporosis.

Alcohol and Periodontal Disease: A Narrative Review

The scientific literature dealing with alcohol and alcoholic beverages revealed that these drinks possess an adverse impact on periodontal tissues. Additionally, other principal risk factors include tobacco, smoking, poor oral hygiene, etc. It has been observed that among chronic alcoholics, there are further issues, such as mental, social, and physical effects, that promote alcoholism. These people may have weak immunity for defense against pathogenic organisms and bacteria. Thus, chances of gingival bleeding, swollen gums, bad breath, and increased bone loss are there. Different alcoholic beverages in the market cause less salivation; these beverages contain sugars that promote acid production in the oral cavity by pathogens that demineralize the enamel and damage gum and teeth. This chronic alcohol consumption can progress into different types of oral disorders, including cancer, halitosis, and caries, and is also associated with tobacco and smoking. Chronic alcohol consumption can cause alteration of the oral microbiome and increase oral pathogens, which lead to periodontal disease and an environment of inflammation created in the body due to malnutrition, diminished immunity, altered liver condition, brain damage, and gut microbiota alteration. Heavily colored alcoholic beverages produce staining on teeth and, due to less saliva, may cause other toxic effects on the periodontium. Over-dependency on alcohol leads to necrotizing lesions such as necrotizing gingivitis, necrotizing periodontitis, and necrotizing stomatitis. These pathological impairments instigate severe damage to oral structures. Therefore, proper counseling by the attending dental surgeon and related health professionals is urgently required for the patient on the basis that the individual case needs to go away from the regular heavy consumption of alcohol.

Gut microbial community and fecal metabolomic signatures in different types of osteoporosis animal models

BACKGROUND

The gut microbiota (GM) constitutes a critical factor in the maintenance of physiological homeostasis. Numerous studies have empirically demonstrated that the GM is closely associated with the onset and progression of osteoporosis (OP). Nevertheless, the characteristics of the GM and its metabolites related to different forms of OP are poorly understood. In the present study, we examined the changes in the GM and its metabolites associated with various types of OP as well as the correlations among them.

METHODS

We simultaneously established rat postmenopausal, disuse-induced, and glucocorticoid-induced OP models. We used micro-CT and histological analyses to observe bone microstructure, three-point bending tests to measure bone strength, and enzyme-linked immunosorbent assay (ELISA) to evaluate the biochemical markers of bone turnover in the three rat OP models and the control. We applied 16s rDNA to analyze GM abundance and employed untargeted metabolomics to identify fecal metabolites in all four treatment groups. We implemented multi-omics methods to explore the relationships among OP, the GM, and its metabolites.

RESULTS

The 16S rDNA sequencing revealed that both the abundance and alterations of the GM significantly differed among the OP groups. In the postmenopausal OP model, the bacterial genera g__Bacteroidetes_unclassified, g__Firmicutes_unclassified, and g__Eggerthella had changed. In the disuse-induced and glucocorticoid-induced OP models, g__Akkermansia and g__Rothia changed, respectively. Untargeted metabolomics disclosed that the GM-derived metabolites significantly differed among the OP types. However, a Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that it was mainly metabolites implicated in lipid and amino acid metabolism that were altered in all cases. An association analysis indicated that the histidine metabolism intermediate 4-(β-acetylaminoethyl) imidazole was common to all OP forms and was strongly correlated with all bone metabolism-related bacterial genera. Hence, 4-(β-acetylaminoethyl) imidazole might play a vital role in OP onset and progression.

CONCLUSIONS

The present work revealed the alterations in the GM and its metabolites that are associated with OP. It also disclosed the changes in the GM that are characteristic of each type of OP. Future research should endeavor to determine the causal and regulatory effects of the GM and the metabolites typical of each form of OP.

Effects of alcohol on the symptoms of gouty arthritis and taxonomic structure of gut microbiota in C57BL/6 mice

Gout is an acute arthritis caused by the elevated levels of serum uric acid (UA), and its prevalence has been rapidly increasing. Alcohol abuse could lead to a series of health problems. Multiple pieces of evidence suggest that alcohol intake affects the development and progression of gout, while the gut microbiota plays an important role in the development of gout and the long-term alcohol consumption could affect the stability of the gut microbiota. This study aimed to explore the effects of alcohol intake at different concentrations on gouty arthritis based on the gut microbiota. We investigated the effects of different concentrations of alcohol on gouty arthritis in mouse models of acute gouty arthritis established by injection of monosodium urate (MSU) crystals into C57BL/6 mice. The results indicated that the high-alcohol consumption not only exacerbated joint swelling and pain, increased the levels of UA, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6), but also showed dramatic effects on the composition and structure of the gut microbiota in gouty mice. Two key microorganisms, Parasutterella and Alistipes, could aggravate gout symptoms through lipopolysaccharide biosynthesis, riboflavin metabolism, phenylalanine metabolism, and arginine and proline metabolisms. In conclusion, our study suggested that high-concentrations of alcohol altered the gut microbiota structure in gouty mice induced by MSU crystals, which could exacerbate gouty symptoms by enhancing pro-inflammatory pathways.

Linking the relation between gut microbiota and glucocorticoid-induced osteoporosis

Osteoporosis (OP) is the most prevalent metabolic bone disease, characterized by the low bone mass and microarchitectural deterioration of bone tissue. Glucocorticoid (GC) clinically acts as one of the anti-inflammatory, immune-modulating, and therapeutic drugs, whereas the long-term use of GC may cause rapid bone resorption, followed by prolonged and profound suppression of bone formation, resulting in the GC-induced OP (GIOP). GIOP ranks the first among secondary OP and is a pivotal risk for fracture, as well as high disability rate and mortality, at both societal and personal levels, vital costs. Gut microbiota (GM), known as the "second gene pool" of human body, is highly correlated with maintaining the bone mass and bone quality, and the relation between GM and bone metabolism has gradually become a research hotspot. Herein, combined with recent studies and based on the cross-linking relationship between GM and OP, this review is aimed to discuss the potential mechanisms of GM and its metabolites on the OP, as well as the moderating effects of GC on GM, thereby providing an emerging thought for prevention and treatment of GIOP.

Chondroitin sulfate alleviates osteoporosis caused by calcium deficiency by regulating lipid metabolism

The use of non-drug intervention for calcium deficiency has attracted attention in recent years. Although calcium carbonate is the preferred raw material for calcium supplementation, there are few reports on the mechanism of the combined action of chondroitin sulfate and calcium to alleviate osteoporosis from the perspective of gut microbiota and metabolomics. In this study, a rat model of osteoporosis was established by feeding a low-calcium diet. The intestinal microbiota abundance, fecal and plasma metabolite expression levels of rats fed a basal diet, a low-calcium diet, a low-calcium diet plus calcium carbonate, and a low-calcium diet plus chondroitin sulfate were compared. The results showed that compared with the low calcium group, the calcium content and bone mineral density of femur were significantly increased in the calcium carbonate and chondroitin sulfate groups. 16 S rRNA sequencing and metabolomics analysis showed that chondroitin sulfate intervention could reduce short-chain fatty acid synthesis of intestinal flora, slow down inflammatory response, inhibit osteoclast differentiation, promote calcium absorption and antioxidant mechanism, and alleviate osteoporosis in low-calcium feeding rats. Correlation analysis showed that the selected intestinal flora was significantly correlated with metabolites enriched in feces and plasma. This study provides scientific evidence of the potential impact of chondroitin sulfate as a dietary supplement for patients with osteoporosis.

A critical review of recent knowledge of alcohol's effects on the immunological response in different tissues

Alcohol misuse contributes to the dysregulation of immune responses and multiorgan dysfunction across various tissues, which are associated with higher risk of morbidity and mortality in people with alcohol use disorders. Organ-specific immune cells, including microglia in the brain, alveolar macrophages in the lungs, and Kupffer cells in the liver, play vital functions in host immune defense through tissue repair and maintenance of homeostasis. However, binge drinking and chronic alcohol misuse impair these immune cells' abilities to regulate inflammatory signaling and metabolism, thus contributing to multiorgan dysfunction. Further complicating these delicate systems, immune cell dysfunction associated with alcohol misuse is exacerbated by aging and gut barrier leakage. This critical review describes recent advances in elucidating the potential mechanisms by which alcohol misuse leads to derangements in host immunity and highlights current gaps in knowledge that may be the focus of future investigations.

Alpinetin alleviates osteoporosis by promoting osteogenic differentiation in BMSCs by triggering autophagy via PKA/mTOR/ULK1 signaling

Osteoporosis, a systemic bone disease that is characterized by a reduction in bone mass and destruction of bone microstructure, is becoming a serious problem worldwide. Bone marrow mesenchymal stem cells (BMSCs) can differentiate into bone-forming osteoblasts, and play an important role in maintaining homeostasis of bone metabolism, thus being a potential therapeutic target for osteoporosis. Although the phytochemical alpinetin (APT) has been reported to possess a variety of pharmacological activities, it is still unclear whether APT can influence the osteogenic differentiation of on BMSCs and if it can improve osteoporosis. In this study, we found that APT treatment was able to enhance osteogenic differentiation levels of human BMSCs in vitro and mouse ones in vivo as revealed by multiple osteogenic markers including increased alkaline phosphatase activity and osteocalcin expression. Mechanistically, the protein kinase A (PKA)/mTOR/ULK1 signaling was involved in the action of APT to enhance the osteogenic differentiation of BMSCs. In addition, oral administration of APT significantly mitigated the bone loss in a dexamethasone-induced mouse model of osteoporosis through strengthening PKA signaling and autophagy. Altogether, these data demonstrate that APT promotes osteogenic differentiation in BMSCs by augmenting the PKA/mTOR/ULK1 autophagy signaling, highlighting its potential therapeutic application for treating osteoporotic diseases.

Gut microbiota and fecal metabolic signatures in rat models of disuse-induced osteoporosis

Background

Assessing the correlation between gut microbiota (GM) and bone homeostasis has increasingly attracted research interest. Meanwhile, GM dysbiosis has been found to be associated with abnormal bone metabolism. However, the function of GM in disuse-induced osteoporosis (DIO) remains poorly understood. In our research, we evaluated the characteristics of GM and fecal metabolomics to explore their potential correlations with DIO pathogenesis.

Methods

DIO rat models and controls (CON) underwent micro-CT, histological analyses, and three-point bending tests; subsequently, bone microstructures and strength were observed. ELISAs were applied for the measurement of the biochemical markers of bone turnover while GM abundance was observed using 16S rDNA sequencing. Metabolomic analyses were used to analyze alterations fecal metabolites. The potential correlations between GM, metabolites, and bone loss were then assessed.

Results

In the DIO group, the abundance of GM was significantly altered compared to that in the CON group. Moreover, DIO significantly altered fecal metabolites. More specifically, an abnormally active pathway associated with bile acid metabolism, as well as differential bacterial genera related to bone/tissue volume (BV/TV), were identified. Lithocholic acid, which is the main secondary bile acid produced by intestinal bacteria, was then found to have a relationship with multiple differential bacterial genera. Alterations in the intestinal flora and metabolites in feces, therefore, may be responsible for DIO-induced bone loss.

Conclusions

The results indicated that changes in the abundance of GM abundance and fecal metabolites were correlated with DIO-induced bone loss, which might provide new insights into the DIO pathogenesis. The detailed regulatory role of GM and metabolites in DIO-induced bone loss needs to be explored further.

Osteoporosis and Alveolar Bone Health in Periodontitis Niche: A Predisposing Factors-Centered Review

Periodontitis is a periodontal inflammatory condition that results from disrupted periodontal host-microbe homeostasis, manifested by the destruction of tooth-supporting structures, especially inflammatory alveolar bone loss. Osteoporosis is characterized by systemic deterioration of bone mass and microarchitecture. The roles of many systemic factors have been identified in the pathogenesis of osteoporosis, including endocrine change, metabolic disorders, health-impaired behaviors and mental stress. The prevalence rate of osteoporotic fracture is in sustained elevation in the past decades. Recent studies suggest that individuals with concomitant osteoporosis are more vulnerable to periodontal impairment. Current reviews of worse periodontal status in the context of osteoporosis are limited, mainly centering on the impacts of menopausal and diabetic osteoporosis on periodontitis. Herein, this review article makes an effort to provide a comprehensive view of the relationship between osteoporosis and periodontitis, with a focus on clarifying how those risk factors in osteoporotic populations modify the alveolar bone homeostasis in the periodontitis niche.

New Advances in Improving Bone Health Based on Specific Gut Microbiota

The gut microbiota has been shown to play an important role in the pathogenesis of various diseases, including metabolic diseases, cardiovascular diseases, and cancer. Recent studies suggest that the gut microbiota is also closely associated with bone metabolism. However, given the high diversity of the gut microbiota, the effects of different taxa and compositions on bone are poorly understood. Previous studies demonstrated that the mechanisms underlying the effects of the gut microbiota on bone mainly include its modulation of nutrient absorption, intestinal permeability, metabolites (such as short-chain amino acids), immune responses, and hormones or neurotransmitters (such as 5-hydroxytryptamine). Several studies found that external interventions, such as dietary changes, improved bone health and altered the composition of the gut microbiota. This review summarises the beneficial gut bacteria and explores how dietary, natural, and physical factors alter the diversity and composition of the gut microbiota to improve bone health, thereby providing potential new insight into the prevention of osteoporosis.

Assessing the Association between Important Dietary Habits and Osteoporosis: A Genetic Correlation and Two-Sample Mendelian Randomization Study

Objective: Osteoporosis (OP) is the most common bone disease. The genetic and metabolic factors play important roles in OP development. However, the genetic basis of OP is still elusive. The study aimed to explore the relationships between OP and dietary habits. Methods: This study used large-scale genome-wide association study (GWAS) summary statistics from the UK Biobank to explore potential associations between OP and 143 dietary habits. The GWAS summary data of OP included 9434 self-reported OP cases and 444,941 controls, and the GWAS summary data of the dietary habits included 455,146 participants of European ancestry. Linkage disequilibrium score regression (LDSC) was used to detect the genetic correlations between OP and each of the 143 dietary habits, followed by Mendelian randomization (MR) analysis to further assess the causal relationship between OP and candidate dietary habits identified by LDSC. Results: The LDSC analysis identified seven candidate dietary habits that showed genetic associations with OP including cereal type such as biscuit cereal (coefficient = −0.1693, p value = 0.0183), servings of raw vegetables per day (coefficient = 0.0837, p value = 0.0379), and spirits measured per month (coefficient = 0.115, p value = 0.0353). MR analysis found that OP and PC17 (butter) (odds ratio [OR] = 0.974, 95% confidence interval [CI] = (0.973, 0.976), p value = 0.000970), PC35 (decaffeinated coffee) (OR = 0.985, 95% CI = (0.983, 0.987), p value = 0.00126), PC36 (overall processed meat intake) (OR = 1.035, 95% CI = (1.033, 1.037), p value = 0.000976), PC39 (spirits measured per month) (OR = 1.014, 95% CI = (1.011, 1.015), p value = 0.00153), and servings of raw vegetables per day (OR = 0.978, 95% CI = (0.977, 0.979), p value = 0.000563) were clearly causal. Conclusions: Our findings provide new clues for understanding the genetic mechanisms of OP, which focus on the possible role of dietary habits in OP pathogenesis.

The Impact of Alcohol-Induced Dysbiosis on Diseases and Disorders of the Central Nervous System

The human digestive tract contains a diverse and abundant microbiota that is important for health. Excessive alcohol use can disrupt the balance of these microbes (known as dysbiosis), leading to elevated blood endotoxin levels and systemic inflammation. Using QIAGEN Ingenuity Pathway Analysis (IPA) bioinformatics tool, we have confirmed that peripheral endotoxin (lipopolysaccharide) mediates various cytokines to enhance the neuroinflammation signaling pathway. The literature has identified alcohol-mediated neuroinflammation as a possible risk factor for the onset and progression of neurodegenerative diseases, including Alzheimer's disease (AD) and Parkinson's disease (PD), and psychiatric disorders such as addiction to alcohol and other drugs. In this review, we discuss alcohol-use-induced dysbiosis in the gut and other body parts as a causal factor in the progression of Central Nervous System (CNS) diseases including neurodegenerative disease and possibly alcohol use disorder.

The Role of Depletion of Gut Microbiota in Osteoporosis and Osteoarthritis: A Narrative Review

Osteoporosis and osteoarthritis are common diseases in an aging society, are considered metabolic diseases, and affect the quality of life of older adults. In addition, the gut microbiome is considered an additional organ to regulate bone metabolism. In the past decade, people have been studying the relationship between gut microbiota and bone metabolism. The role and mechanism of the gut microbiota in regulating bone metabolism is very important to improve the development of osteoporosis and osteoarthritis. Depletion of the gut microbiota as a method of studying the role of the gut microbiota was provided strategies to enhance the role of the gut microbiota in regulating osteoporosis and osteoarthritis. In this review, we discuss how depletion of the gut microbiota affects osteoporosis and osteoarthritis.