Chronic cold environment regulates rheumatoid arthritis through modulation of gut microbiota-derived bile acids

Natural environmental factors at birth on risk for rheumatoid arthritis: the impact of season, temperature, latitude, and sunlight exposure

BACKGROUND

Environmental factors contribute to approximately 41% of the risk of rheumatoid arthritis (RA). Previous studies have focused on anthropogenic environmental factors, while much less attention has been given to natural environmental factors. Our study explored the potential influence of natural environmental factors at birth on the risk of RA.

METHODS

This large retrospective study utilized data from the China Kadoorie Biobank. A restricted cubic spline (RCS) model was employed to explore nonlinear relationships between natural environmental factors and the risk of RA. Additionally, a multivariable Cox regression model, adjusted for confounding factors, was used to examine correlations between season of birth, geographic, climate, and the risk of RA.

RESULTS

A total of 512,715 participants were included in this study, of which 2889 (0.56%) were diagnosed with RA. The RCS analysis revealed that the monthly average temperature at birth (p < 0.001), the latitude (p = 0.027) of the birthplace, and the sunshine rate (p < 0.001) exhibited a nonlinear relationship with the risk of RA. Multivariable Cox regression analysis revealed that participants born in Spring and Summer (HR 1.13, 95% CI 1.05-1.23) had an increased risk of RA compared to those born in Autumn and Winter. Additionally, participants born at latitudes ≤ 24°N (HR 1.49, 95% CI 1.32-1.68), with sunshine rate ≤ 28% (HR 2.00, 95% CI 1.75-2.29) or ≥ 60% (HR 1.22, 95% CI 1.08-1.38) had an increased risk of RA. Being born in regions with a monthly average temperature ≥ 27 °C (HR 0.82, 95% CI 0.72-0.95) was associated with a decreased risk of RA.

CONCLUSION

Being born in Spring and Summer, as well as early-life exposure to low-latitude regions and extreme sunlight environments increases the risk of RA. Our study revealed significant associations between the risk of RA and natural environmental factors at birth, emphasizing the impact of the early-life environment on the onset of RA.

Causal associations between 26 musculoskeletal disorders and gut microbiota: a Mendelian randomization analysis with Bayesian validation

Emerging evidence suggests that gut microbiota imbalances may influence the onset of musculoskeletal disorders (MSDs), yet conclusive evidence establishing causation remains limited. This study investigates the causal relationship between gut microbiota and a range of MSDs, aiming to identify potential therapeutic targets. Using data on 211 gut microbiome taxa from a genome-wide association study (GWAS) and summary statistics for 26 MSDs from the Finnish Biobank, we employed Mendelian randomization (MR) with inverse-variance weighting (IVW) as the primary analytical approach, complemented by Bayesian model validation to ensure robust results. Our MR analyses revealed significant causal associations between gut microbiota and nine MSDs within four categories, including osteoporosis (IVW-Beta = 0.011, P = 0.025), rheumatoid arthritis (IVW-Beta = - 0.016, P < 0.001), rotator cuff syndrome (IVW-Beta = - 0.007, P = 0.022), and calcific tendonitis of the shoulder (IVW-Beta = - 0.021, P = 0.034). Bayesian validation underscored the plausibility of these relationships, supporting the potential causal role of gut microbiota in the development of these disorders. Our findings present a library of causal associations that underscore the gut microbiome's role in MSD pathogenesis, providing genetic evidence that highlights specific gut microbiota taxa as prospective therapeutic targets. This research offers novel insights into the pathogenic mechanisms underlying MSDs and points toward new directions for future investigation into microbiome-based therapies.

New Dawn in the Treatment of Rheumatoid Arthritis: Advanced Insight into Polymer Hydrogel Research

As a chronic systemic autoimmune disease, rheumatoid arthritis (RA) not only damages joints and other organs or systems throughout the body but also torments patients' physical and mental health for a long time, seriously affecting their quality of life. According to incomplete statistics at present, the global prevalence of RA is approximately 0.5-1%, and the number of patients is increasing year by year. Currently, drug therapies are usually adopted for the treatment of RA, such as non-steroidal anti-inflammatory drugs (NSAIDs), disease-modifying antirheumatic drugs (DMARDs), glucocorticoids/steroids, and so on. However, traditional drug therapy has problems such as long half-lives, long treatment cycles requiring frequent drug administration, lack of specificity, and other possible adverse reactions (such as gastrointestinal side effects, skin stratum corneum barrier damage, and systemic toxicity), which greatly restrict the treatment of RA. In order to improve the limitations of traditional drug, physical, and surgical treatments for RA, a large number of related studies on the treatment of RA have been carried out. Among them, hydrogels have been widely used in the research on the treatment of RA due to their excellent biocompatibility, mechanical properties, and general adaptability. For example, hydrogels can be injected into the synovial cavity of joints as synovial fluid to reduce wear between joints, lubricate joints, and avoid synovial surface degradation. This article reviews the applications of hydrogels in the treatment of RA under different functions and the situation of hydrogels as carriers in the treatment of RA through different drug delivery routes and confirms the outstanding potential of hydrogels as drug carriers in the treatment of RA, which has great research significance.

Senile Osteoarthritis Regulated by the Gut Microbiota: From Mechanisms to Treatments

Osteoarthritis (OA) is a chronic, progressive degenerative joint disease that affects the entire synovial joint, leading to the progressive degeneration of articular cartilage. It seriously affects the quality of life and global disability of patients. OA is affected by a variety of factors; the most significant risk factor for OA is age. As individuals age, the risk and severity of OA increase due to the exacerbation of cartilage degeneration and wear and tear. In recent years, research has indicated that the gut microbiota may play a significant role in the aging and OA processes. It is anticipated that regulating the gut microbiota may offer novel approaches to the treatment of OA. The objective of this paper is to examine the relationship between the gut microbiota and senile OA, to investigate the potential mechanisms involved. This review also summarizes the therapeutic strategies related to gut flora in OA management, such as prebiotics and probiotics, diet, exercise, traditional Chinese medicine (TCM) modification, and fecal microbiota transplantation (FMT), highlighting the potential clinical value of gut flora and elucidating the current challenges. The foundation for future research directions is established through the summarization of current research progress.

The energy metabolism-promoting effect of aconite is associated with gut microbiota and bile acid receptor TGR5-UCP1 signaling

Introduction

As a widely used traditional Chinese medicine with hot property, aconite can significantly promote energy metabolism. However, it is unclear whether the gut microbiota and bile acids contribute to the energy metabolism-promoting properties of aconite. The aim of this experiment was to verify whether the energy metabolism-promoting effect of aconite aqueous extract (AA) is related to gut microbiota and bile acid (BA) metabolism.

Methods

The effect of AA on energy metabolism in rats was detected based on body weight, body temperature, and adipose tissue by HE staining and immunohistochemistry. In addition, 16S rRNA high-throughput sequencing and targeted metabolomics were used to detect changes in gut microbiota and BA concentrations, respectively. Antibiotic treatment and fecal microbiota transplantation (FMT) were also performed to demonstrate the importance of gut microbiota.

Results

Rats given AA experienced an increase in body temperature, a decrease in body weight, and an increase in BAT (brown adipose tissue) activity and browning of WAT (white adipose tissue). Sequencing analysis and targeted metabolomics indicated that AA modulated gut microbiota and BA metabolism. The energy metabolism promotion of AA was found to be mediated by gut microbiota, as demonstrated through antibiotic treatment and FMT. Moreover, the energy metabolism-promoting effect of aconite is associated with the bile acid receptor TGR5 (Takeda G-protein-coupled receptor 5)-UCP1 (uncoupling protein 1) signaling pathway.

Conclusion

The energy metabolism-promoting effect of aconite is associated with gut microbiota and bile acid receptor TGR5-UCP1 signaling.

The role of botanical triterpenoids and steroids in bile acid metabolism, transport, and signaling: Pharmacological and toxicological implications

Bile acids (BAs) are synthesized by the host liver from cholesterol and are delivered to the intestine, where they undergo further metabolism by gut microbes and circulate between the liver and intestines through various transporters. They serve to emulsify dietary lipids and act as signaling molecules, regulating the host's metabolism and immune homeostasis through specific receptors. Therefore, disruptions in BA metabolism, transport, and signaling are closely associated with cholestasis, metabolic disorders, autoimmune diseases, and others. Botanical triterpenoids and steroids share structural similarities with BAs, and they have been found to modulate BA metabolism, transport, and signaling, potentially exerting pharmacological or toxicological effects. Here, we have updated the research progress on BA, with a particular emphasis on new-found microbial BAs. Additionally, the latest advancements in targeting BA metabolism and signaling for disease treatment are highlighted. Subsequently, the roles of botanical triterpenoids in BA metabolism, transport, and signaling are examined, analyzing their potential pharmacological, toxicological, or drug interaction effects through these mechanisms. Finally, a research paradigm is proposed that utilizes the gut microbiota as a link to interpret the role of these important natural products in BA signaling.

Unraveling the gut microbiota's role in Rheumatoid arthritis: dietary pathways to modulation and therapeutic potential

Rheumatoid arthritis (RA) is a significant global health issue. Recent research highlights the gut microbiota's critical role in RA's development, noting how dietary factors can alter these microbial communities. This has led to an increased focus on how the gut microbiota (GM) influences RA and the potential for dietary ingredients to offer anti-RA benefits by modifying GM. This review presents a concise examination of the GM associated with RA, identifying specific microbial taxa at various levels that are implicated in the disease. It delves into dietary components known for their anti-RA properties through GM modulation and their mechanisms. Findings from numerous studies, including both animal and human research, show significant differences in the GM composition between individuals with early and established RA. Certain microbes like Tenericutes, Synergistetes, and Proteobacteria have been linked to RA progression, whereas Bacteroidetes and some strains of Lactobacillus are shown to have protective effects against RA. Dietary elements such as fibers, polysaccharides, resistant starch, and peptides have been identified as influential in combating RA. These components work by altering the GM's metabolites and impacting immune cells related to the GM. This review suggests the potential for developing functional foods aimed at treating RA by targeting GM.

Multispecies probiotics complex improves bile acids and gut microbiota metabolism status in an in vitro fermentation model

The consumption of probiotics has been extensively employed for the management or prevention of gastrointestinal disorders by modifying the gut microbiota and changing metabolites. Nevertheless, the probiotic-mediated regulation of host metabolism through the metabolism of bile acids (BAs) remains inadequately comprehended. The gut-liver axis has received more attention in recent years due to its association with BA metabolism. The objective of this research was to examine the changes in BAs and gut microbiota using an in vitro fermentation model. The metabolism and regulation of gut microbiota by commercial probiotics complex containing various species such as Lactobacillus, Bifidobacterium, and Streptococcus were investigated. The findings indicated that the probiotic strains had produced diverse metabolic profiles of BAs. The probiotics mixture demonstrated the greatest capacity for Bile salt hydrolase (BSH) deconjugation and 7α-dehydroxylation, leading to a significant elevation in the concentrations of Chenodeoxycholic acid, Deoxycholic acidcholic acid, and hyocholic acid in humans. In addition, the probiotic mixtures have the potential to regulate the microbiome of the human intestines, resulting in a reduction of isobutyric acid, isovaleric acid, hydrogen sulfide, and ammonia. The probiotics complex intervention group showed a significant increase in the quantities of Lactobacillus and Bifidobacterium strains, in comparison to the control group. Hence, the use of probiotics complex to alter gut bacteria and enhance the conversion of BAs could be a promising approach to mitigate metabolic disorders in individuals.