The impact of short-chain fatty acid-producing bacteria of the gut microbiota in hyperuricemia and gout diagnosis

Sodium butyrate promotes synthesis of testosterone and meiosis of hyperuricemic male mice

Hyperuricemia (HUA) impaires spermatogenesis. This study was carried out, aiming to determine whether butyric acid (NaB) avoids the HUA-induced decline of sperm quality HUA mice were developed through intra-peritoneal injection of the potassium oxalate combined with intragastric uric acid (UA) and by tube feeding 300 mg·kg-1·d-1NaB. The effect of NaB on the reproduction of HUA male mice was determined by measuring sperm count, sperm motility and testosterone content. In addition, TM3 and GC-2 cells were treated with a solution containing 30 mg/dl UA and 1mM NaB. The effects of NaB on the sperm quality were evaluated with the expression level of the genes involving in LH/cAMP/PKA signaling pathway and meiosis, and that encoding OPRL1 receptor protein. Results showed that NaB improved sperm count, sperm motility, testosterone synthesis, and impaired spermatocyte meiosis via HUA. In addition, in vitro analysis showed that NaB activated the LH/cAMP/PKA signaling pathway of TM3 cells, promoted the synthesis of testosterone, up-regulated the content of pain-sensitive peptide receptor (OPRL1) on the surface of GC-2 cells, and promoted meiosis. NaB also promoted the utilization of ATP by GC-2 cells. We illustrated a close relationship between HUA and spermatogenesis defects. NaB-promoted the expression of the genes functioning in testis meiosis, and the testosterone content may aid to improving spermatogenesis quality.

Uric Acid-Degrading Lacticaseibacillus paracasei CPU202306 Ameliorates Hyperuricemia by Regulating Uric Acid Metabolism and Intestinal Microecology in Mice

Hyperuricemia, characterized by elevated levels of uric acid in the blood, poses a significant health threat due to its association with various adverse health outcomes, and lactic acid bacteria from the gut microbiota may offer solutions. Our investigation focused on Lacticaseibacillus paracasei CPU202306, isolated from fermented pickles for its potent uric acid degradation and probiotic properties. This bacterium effectively reduced blood uric acid levels by breaking down uric acid and inhibiting hepatic xanthine oxidase (XOD) and adenosine deaminase (ADA) enzymes. Additionally, it stimulated the production of short-chain fatty acid (SCFAs) in the colon, enhancing the expression of uric acid secretion transport proteins (ATP-binding cassette sub-family G member 2 and organic anion transporter 3) while suppressing absorption transport proteins (glucose transporter 9 and uric acid transporter 1). This orchestrated process promoted uric acid excretion. L. paracasei CPU202306 also improved gut microbiota health by reinforcing tight junction proteins, shifting the microbiota to a healthier composition, and reducing harmful bacteria. This transformation inhibited kidney TLR4/MyD88/NF-κB inflammatory signaling, leading to a significant decrease in pro-inflammatory cytokines and an increase in anti-inflammatory cytokines, mitigating kidney inflammation. Furthermore, the bacterium supported kidney health by influencing amino acid metabolic pathways linked to the gut-kidney axis. In summary, our study highlights the diverse mechanisms through which L. paracasei CPU202306 addresses hyperuricemia, showcasing its therapeutic potential for this condition.

Investigating the modulatory effects of Pu-erh tea on the gut microbiota in ameliorating hyperuricemia induced by circadian rhythm disruption

Circadian rhythm disruption (CRD) can induce a variety of metabolic disorders. Our previous laboratory studies have shown that Pu-erh tea could alleviate CRD-induced syndromes, including obesity, intestinal dysfunction, and tryptophan metabolism disorders. However, its potential protective mechanism against CRD-induced hyperuricaemia remains unclear. In this work, we found that polyphenols of Pu-erh tea were significantly released in the stage of intestinal digestion, which might promote their interaction with gut microbes. Through animal experiments, C57BL6/J mice were given water or different doses of Pu-erh tea for 60 days, followed by a 90-day CRD, the lifestyle of modern individuals who frequently stay up late. Our results indicated that CRD mice exhibited high serum uric acid levels and gut microbiota disorders. Pu-erh tea intake significantly reshaped the gut microbiome, especially increasing the abundance of Bifidobacterium, Akkermansia and Faecalibaculum, and increased the production of short-chain fatty acids (SCFAs), especially acetic acid, which restored the function of the intestinal barrier. This improvement further regulated oxidative stress pathways (NRF2/HO-1), reduced systemic inflammatory response (IL-6, IL-1β, and TNF-α), restored hepatic function (SOD, MOD, CAT, and GSH) and modulated the activity of enzymes related to UA metabolism in the liver (XOD and ADA). Finally, Pu-erh tea intake promoted the excretion of UA and reduced the levels of UA and xanthine in the serum. Moreover, the results of antibiotic experiments showed that the UA improvement effect of Pu-erh tea depended on the existence of the gut microbiota. Collectively, Pu-erh tea intake has the potential to prevent CRD-induced hyperuricaemia by reshaping the gut microbiota.

Metatranscriptomic analysis reveals gut microbiome bacterial genes in pyruvate and amino acid metabolism associated with hyperuricemia and gout in humans

Several pathologies with metabolic origin, such as hyperuricemia and gout, have been associated with the gut microbiota taxonomic profile. However, there is no evidence of which bacterial genes are being expressed in the gut microbiome, and of their potential effects on hyperuricemia and gout. We sequenced the RNA of 26 fecal samples from 10 healthy normouricemic controls, 10 with asymptomatic hyperuricemia (AH), and six gout patients. The coding sequences were mapped to KEGG orthologues (KO). We compared the expression levels using generalized linear models and validated the expression of four KO in a larger sample by qRT-PCR. A distinct genetic expression pattern was identified among groups. AH individuals and gout patients showed an over-expression of KOs mainly related to pyruvate metabolism (Log2foldchange > 23, p-adj ≤ 3.56 × 10- 9), the pentose pathway (Log2foldchange > 24, p-adj < 1.10 × 10-12) and purine metabolism (Log2foldchange > 22, p-adj < 1.25 × 10- 7). AH subjects had lower expression of KO related to glycine metabolism (Log2foldchange=-18, p-adj < 1.72 × 10-6) than controls. Gout patients had lower expression (Log2foldchange=-22.42, p-adj < 3.31 × 10- 16) of a KO involved in phenylalanine biosynthesis, in comparison to controls and AH subjects. The over-expression seen for the KO related to pyruvate metabolism and the pentose pathway in gout patients´ microbiome was validated. There is a differential gene expression pattern in the gut microbiome of normouricemic individuals, AH subjects and gout patients. These differences are mainly located in metabolic pathways involved in acetate precursors and bioavailability of amino acids.

Integrated Data Mining and Animal Experiments to Investigate the Efficacy and Potential Pharmacological Mechanism of a Traditional Tibetan Functional Food Terminalia chebula Retz. in Hyperuricemia

Background

Hyperuricemia (HUA), a common metabolic disorder associated with gout, renal dysfunction, and systemic inflammation, necessitates safer and more comprehensive therapeutic approaches. Traditional Tibetan medicine has a rich history of treating HUA. This study aimed to identify novel anti-hyperuricemic herb derived from traditional Tibetan medicine.

Methods

Traditional Tibetan medicine prescriptions for HUA were analyzed using data mining techniques, identifying T. chebula as a high-frequency herb. Its phytochemical composition was characterized by UPLC-QE-Orbitrap-MS. Hyperuricemic rat models were treated with T. chebula to assess its effects on serum uric acid (UA) levels, renal inflammation, intestinal barrier integrity, and gut microbiota composition. Molecular and histological analyses evaluated its impact on key biomarkers.

Results

Through data mining, we identified T. chebula as a promising candidate for HUA treatment. T. chebula demonstrated dose-dependent inhibition of xanthine oxidase (XOD) in vitro and significantly reduced serum UA levels and XOD activity in vivo. It restored gut barrier function by upregulating tight junction proteins (ZO-1, Occludin, Claudin-1) and reduced pro-inflammatory cytokines (IL-6, TNF-α). T. chebula improved renal function, reducing serum creatinine (Cre) and blood urea nitrogen (BUN) levels. Gut microbiota analysis revealed a favorable shift in microbial composition, with reductions in harmful bacteria (eg, Clostridium spp.) and increases in beneficial bacteria (eg, Roseburia). These effects aligned with the modulation of the gut-kidney axis.

Conclusion

This study highlights the multi-target therapeutic potential of T. chebula in HUA management. By regulating the gut-kidney axis, T. chebula alleviates systemic inflammation, enhances intestinal and renal health, and addresses critical aspects of HUA pathology. These findings underscore the value of integrating traditional medicine with modern scientific methodologies to develop innovative treatments.

Regulating Lipid Metabolism in Gout: A New Perspective with Therapeutic Potential

Gout is a metabolic disease characterized by inflammatory arthritis caused by abnormal uric acid metabolism. It is often complicated with cardio-renal damage and vascular lesions. In recent years, the relationship between lipid metabolism and gout has attracted increasing attention. Changes in blood lipids in gout patients are often clinically detectable and closely related to uric acid metabolism and inflammatory response in gout. With the development of lipidomics, the changes in small lipid molecules and their metabolic pathways have been gradually discovered, yielding a greater understanding of the lipid metabolism changes in gout patients and their potential role in gout development. Through searching the literature on lipid metabolism in gout since 2000 in PubMed and Web of Science, this article reviewed lipid metabolism changes in gout patients and their role in the risk of gout, uric acid metabolism, inflammatory response, and comorbidities. Additionally, the strategies to regulate the abnormal lipid metabolism in gout have also been summarized from the aspects of drugs, diet, and exercise. These will provide a new perspective for understanding gout pathogenesis and its treatment and management.

Reassessing Gout Management through the Lens of Gut Microbiota

Gout, recognized as the most common form of inflammatory arthritis, arises from the accumulation of uric acid crystals, leading to intense pain, particularly in the big toe. This condition has traditionally been associated with the overproduction or reduced clearance of uric acid. Recent studies, however, have underscored the significant role of the gut microbiota in uric acid metabolism, impacting both its production and elimination. This emerging understanding suggests that maintaining gut health could offer innovative approaches to treating gout, complementing traditional dietary and pharmacological interventions. It highlights the potential of probiotics or microbiome-based therapies, indicating a future where treatments are tailored to an individual’s microbiome. This offers a fresh perspective on gout management and underscores the broader influence of the microbiota on health and disease.

Assessing the causal relationships of gut microbial genera with hyperuricemia and gout using two-sample Mendelian randomization

BACKGROUND AND AIMS

The causal relationship between gut microbiota and gout and hyperuricemia (HUA) has not been clarified. The objective of this research was to evaluate the potential causal effects of gut microbiota on HUA and gout using a two-sample Mendelian randomization (MR) approach.

METHODS AND RESULTS

Genetic instruments were selected using summary statistics from genome-wide association studies (GWASs) comprising a substantial number of individuals, including 18,473 participants for gut microbiome, 288,649 for serum urate (SU), and 763,813 for gout. Two-sample MR analyses were performed to determine the possible causal associations of gut microbial genera with the risk of HUA and gout using the inverse-variance weighted (IVW) method, and robustness of the results was confirmed by several sensitivity analyses. A reverse MR analysis was conducted on the bacterial taxa that were identified in forward MR analysis. Based on the results of MR analyses, Escherichia-Shigella (OR = 1.05; 95% CI, 1.01-1.08; P = 0.009) exhibited a positive association with SU levels, while Lachnospiraceae NC2004 group (OR = 0.95; 95% CI, 0.92-0.98; P = 0.001) and Family XIII AD3011 group (OR = 0.94; 95% CI, 0.90-0.99; P = 0.015) were associated with a reduced HUA risk. Moreover, Coprococcus 3 (OR = 1.17, 95% CI: 1.01-1.34, P = 0.031) was causally associated with a higher gout risk. In reverse MR analysis, no causal relationships were identified between these bacterial genera and HUA or gout.

CONCLUSION

This study provides evidence for a causal association between gut microbial genera and HUA or gout, and further investigations of the underlying mechanism are warranted.

The microbiome and rheumatic heart disease: current knowledge and future perspectives

Rheumatic heart disease (RHD) is a cardiovascular disease caused by an autoimmune response to group A Streptococcus (GAS) infection resulting in the damage of heart valves. RHD is the most commonly acquired heart disease among children and young adults with a global burden of over 40 million cases accounting for 306,000 deaths annually. Inflammation in the heart valves caused due to molecular mimicry between the GAS antigens and host cardiac proteins is facilitated by cytokines, cross-reactive antibodies and CD4⁺ T cells. The complex interaction between genetic and environmental factors linked with erratic events leads to the loss of immunological tolerance and autoimmunity in RHD. Despite extensive research on the etiopathogenesis of RHD, the precise mechanism underpinning the initiation of acute rheumatic fever (ARF) to the progression of RHD still remains elusive. Mounting evidences support the contribution of the human microbiome in the development of several immune-mediated diseases including rheumatoid arthritis, juvenile idiopathic arthritis, Kawasaki disease, inflammatory bowel disease and type 1 diabetes. The microbiome and their metabolites could play a crucial role in the integrity of the epithelial barrier, development of the immune system, inflammation and differentiation of T cell subsets. Consequently, microbiome dysbiosis might result in autoimmunity by molecular mimicry, epitope spreading and bystander activation. This review discusses various aspects of the interaction between the microbiome and the immune system in order to reveal causative links relating dysbiosis and autoimmune diseases with special emphasis on RHD.