A dynamics association study of gut barrier and microbiota in hyperuricemia

Quercetin ameliorates hyperuricemic nephropathy through improving gut dysfunctions and decreasing gut bacteria-derived uremic toxins

BACKGROUND

Hyperuricemia (HUA) is closely associated with gut dysbiosis, yet the role of microbial metabolism in hyperuricemic nephropathy (HN) remains poorly understood. Quercetin has shown urate-lowering and nephroprotective effects, but its therapeutic mechanisms, particularly in modulating the gut microbiome and microbial metabolism, remain elusive.

PURPOSE

This study investigates the therapeutic effects of quercetin on HN and explores its role in regulating host-microbial co-metabolism.

METHODS

A spontaneous HUA rat model (Uox-/- rats) was used to evaluate the therapeutic effect of quercetin. Multi-omics analyses, including gut microbiome profiling, peripheral untargeted metabolome, and targeted quantification of gut bacteria-derived uremic toxins, were performed. An integrated network analysis was conducted to uncover potential host-microbe metabolic interactions.

RESULTS

Quercetin treatment significantly reduced serum uric acid, creatinine, and blood urea nitrogen, ameliorated renal inflammation, fibrosis and oxidative stress, and improved gut dysbiosis and intestinal barrier dysfunction. Notably, high-dose quercetin downregulated Blautia, a key gut bacterium associated with uremic toxin production, and suppressed microbial phenylalanine metabolism, leading to decreased levels of gut bacteria-derived nephrotoxic metabolites (e.g., 3-phenyllactic acid, hippuric acid, and N-acetyl-l-phenylalanine). These uremic toxins were positively correlated with markers of kidney injury and proinflammatory cytokines. Mechanistically, quercetin modulated microbial enzymatic pathways involved in phenylalanine metabolism, thereby disrupting the formation of nephrotoxic metabolites and alleviating renal damage.

CONCLUSIONS

This study provides multi-omics evidence that quercetin ameliorates HN by regulating gut dysfunctions and decreasing gut bacteria-derived uremic toxins through host-microbial co-metabolism. These findings highlight the therapeutic potential of microbiota-targeted interventions in HUA-associated kidney diseases.

Gut Microbiota in Heart Failure-The Role of Inflammation

Heart failure (HF) has become an immense health concern affecting almost 1-2% of the population globally. It is a complex syndrome characterized by activation of the sympathetic nervous system and the Renin-Angiotensin-Aldosterone (RAAS) axis as well as endothelial dysfunction, oxidative stress, and inflammation. The recent literature points towards the interaction between the intestinal flora and the heart, also called the gut-heart axis. The human gastrointestinal tract is naturally inhabited by various microbes, which are distinct for each patient, regulating the functions of many organs. Alterations of the gut microbiome, a process called dysbiosis, may result in systemic diseases and have been associated with heart failure through inflammatory and autoimmune mechanisms. The disorder of intestinal permeability favors the translocation of microbes and many metabolites capable of inducing inflammation, thus further contributing to the deterioration of normal cardiac function. Besides diet modifications and exercise training, many studies have revealed possible gut microbiota targeted treatments for managing heart failure. The aim of this review is to demonstrate the impact of the inflammatory environment induced by the gut microbiome and its metabolites on heart failure and the elucidation of these novel therapeutic approaches.

A dynamic study on serum biomarkers and kidney injury in a gosling model of hyperuricemia

Hyperuricemia, a metabolic disorder characterized by elevated serum uric acid levels, poses significant challenges to poultry health and productivity. This study aimed to establish a hyperuricemia model in goslings through a multi-factorial induction approach using a high-purine, high-protein, and high-calcium diet, to investigate its dynamic progression, serological markers, and renal pathology. A total of 160 male Sanhua goslings were randomly assigned to control and model groups and fed either a basal diet or a high-purine, high-protein, and high-calcium diet for 18 days. Key findings revealed significant elevations in serum uric acid, creatinine, and urea nitrogen levels in the model group from day 5 onward, peaking on day 13 (p < 0.01). Activities of xanthine oxidase and adenosine deaminase were consistently higher in the model group, indicating enhanced purine metabolism and oxidative stress. Histopathological analysis showed progressive renal damage, including tubular degeneration, interstitial fibrosis, and glomerular injury, becoming evident by day 7 and severe by day 13. Ultrastructural examination further revealed mitochondrial dysfunction, podocyte effacement, and basement membrane disruption in the model group. Behavioral abnormalities, such as reduced mobility and the "shrinking neck" phenomenon, were observed from day 9, reflecting systemic disease severity. The dynamic expression of fibrosis-related markers, including Col-1, Col-3, and α-SMA, demonstrated the progression of renal fibrosis and extracellular matrix remodeling. These findings identify biomarkers for hyperuricemia progression and suggest potential therapeutic targets. This study establishes a comprehensive framework for understanding hyperuricemia-associated renal pathology and lays the groundwork for developing strategies to mitigate its impact on poultry health and productivity.

Protective Effects of a Polyherbal Mixture on Intestinal Injury via the NF-κB Signaling Pathway and Gut Microbiota Modulation in Hyperuricemic Mice

This study investigated the protective effects of a polyherbal tea (PHT) on intestinal injury in hyperuricemia (HUA) mice and the underlying mechanisms. PHT was orally administered to mice for 49 days, while potassium oxonate and hypoxanthine were administered 7 days after PHT administration and continued for 42 days to cause HUA. Treatment with PHT significantly reduced serum uric acid and blood urea nitrogen levels in HUA mice. It also inhibited liver xanthine oxidase activity and promoted intestinal uric acid excretion through the upregulation of transporters GLUT9 and ABCG2. Intestinal barrier integrity was reinforced, as evidenced by the restoration of the villous structure, reduction in edema, and upregulation of tight junction proteins (occludin, ZO-1) and mucin (MUC2). Moreover, PHT suppressed serum LPS levels and inhibited the NF-κB pathway, leading to a reduction in TNF-α and IL-6 levels in the gut. Gut microbiota analysis revealed PHT reversed dysbiosis, enriching beneficial bacteria like Duncaniella sp. and Heminiphilus faecis. By UPLC-MS analysis, 154 compounds of PHT persisted in the gut, suggesting that these compounds are likely to modulate both intestinal barrier function and gut microbiota. These findings suggest that this PHT may have potential as a functional food for the prevention of hyperuricemia.

Gout drives metabolic dysfunction-associated steatotic liver disease through gut microbiota and inflammatory mediators

This study explores the relationship between gout and metabolic dysfunction-associated steatotic liver disease (MASLD), two metabolic conditions linked to worsening health outcomes. While hyperuricemia's association with MASLD is established, the specific connection between gout and MASLD remains less explored. Using data from the UK Biobank, the study employs COX proportional hazard models, multi-state survival analysis, and Mendelian randomization to assess the independent and mutual risks of gout and MASLD. Findings indicate a mutual risk increase: male gout patients, those younger than 60, and those with high BMI are particularly susceptible to MASLD, while female MASLD patients are at heightened risk for gout. Shared risk factors for both conditions include high BMI, hypertension, diabetes, and hyperuricemia. The study further identifies a bidirectional causal link, with gout leading to MASLD, mediated by gut microbiota Ruminococcaceae and proteins like IL-2 and GDF11, implicating specific metabolic pathways. The findings highlight a clinical and mechanistic correlation, emphasizing the need for targeted interventions to address these overlapping metabolic pathways in future treatments.

Anti-hyperuricemia effects of a polysaccharide-protein complex from Lentinula edodes mediated by gut-kidney axis

In order to investigate the effects of Lentinula edodes (L. edodes) on hyperuricemia, a polysaccharide-protein complex (LEPP) was prepared and characterized, and the activity was also systematically studied. LEPP was mainly composed of proteins (18.55 %) and polysaccharides (36.98 %) with three polysaccharide fractions (molecular weights were 8.98 × 106, 7.34 × 107 and 1.15 × 107 g/mol). The experiment results showed that 250-1000 mg/kg/day LEPP could decrease the serum uric acid (UA) level from 281.62 to 109.42-138.12 μmol/L (p < 0.001), and there were significant differences between high and low doses (p < 0.05). LEPP simultaneously improved renal function, relieved oxidative stress and inflammation in the kidney and regulated renal UA transporters (URAT1, GLUT9, OAT1 and ABCG2) of hyperuricemia rats. Furthermore, gut microbiota dysbiosis and intestinal barrier function disruption were modified by LEPP. Among them, LEPP could reverse the relative abundances of Parabacteroides, Lachnospiraceae, Colidextribacter, UCG-010, Monoglobus, Lactobacillus and Muribaculaceae, which were associated with regulating the UA level, renal function and the expression of renal UA transporters in hyperuricemia rats through correlation analysis. Conclusively, LEPP prevented the pathological process of hyperuricemia through regulating the gut-kidney axis, which provided its complementary role in existing anti-hyperuricemia treatment strategies.

Potential of traditional Chinese medicine lyophilized powder of Poecilobdella manillensis in the treatment of hyperuricemia

Traditional Chinese medicine has a long and illustrious history, and with the development of modern science and technology, the research and application of traditional Chinese medicines have continued to progress significantly. Many traditional Chinese medicinal herbs have undergone scientific validation, reinvigorating with new life and vitality, and contributing unique strengths to the advancement of human health. Recently, the discovery that leech total protein extracted from Poecilobdella manillensis lyophilized powder reduces blood uric acid (UA) levels by inhibiting the activity of xanthine oxidase to decrease UA synthesis and promotes UA excretion by regulating different UA transporters in the kidney and intestine has undoubtedly injected new vitality and hope into this field of research. The purpose of this editorial is to comment on this study, explore its strengths and weaknesses, and there is a hope to treat a range of metabolic-related syndromes, including hyperuricemia, by targeting the gut microbiota.

Mechanism of intestinal flora affecting SLC2A9 transport function to promote the formation of hyperuricemia

Objective

To investigate the structural characteristics of the intestinal flora in obese-hyperuricemic (HUA-W) patients and the mechanisms by which they promote the formation of hyperuricemia.

Methods

120 human fecal samples (60 cases in HC, 30 cases in HUA-N, and 30 cases in HUA-W) and 40 cases in the colonic tissues (20 cases in HC, 10 cases in HUA-N, and 10 cases in HUA-W) were collected. The intestinal flora of faeces was detected by 16s rRNA method; and the expression of SLC2A9 on human colon tissues was detected by RT-qPCR method and immunofluorescence method. 40 obese-hyperuricemia rat models were established (10 rats in Model, 10 rats in HC-FT, 10 rats in HUA-N-FT, and 10 rats in HUA-W-FT), and 10 rats were set up in Control; and the level of uric acid in rat serum, the levels of xanthine oxidase (XOD) activity and uric acid in intestinal fluid were examined. SLC2A9+ Caco-2 cells were produced to simulate the Transwell uric acid transport model, and the Caco-2 cells and SLC2A9+ Caco-2 cells were grown in five different culture media (Blank, Germ-free, HC-germ, HUA-N-germ and HUA-W-germ), and the uric acid levels in the upper and lower layers of the chambers were detected.

Results

The HUA-W intestinal flora showed significant specificity, with a decrease in Bacteroidota and Bacteroidia and an increase in Escherichia and Ruminococcus. There were no significant differences in the fluorescence intensity of the SLC2A9 protein and the SLC2A9 mRNA levels in the colon tissues of the HUA-N and HUA-W (P = 0.447, P = 0.152, P = 0.4799 and P = 0.965, respectively). In rat animal experiments, uric acid levels were significantly higher (P < 0.05) and XOD activity was significantly higher (P < 0.05) in intestinal fluid of HUA-W-FT. In Transwell experiments with SLC2A9+ Caco-2 cells, uric acid levels were increased in the upper compartment and decreased in the lower compartment of HUA-W-germ.

Conclusion

HUA-W intestinal flora may increase XOD activity in the intestinal tract and improve the ability of uric acid transporter protein SLC2A9 to reabsorb uric acid, providing a new theoretical basis for the pathogenesis of hyperuricemia.

Hyperuricemia drives intestinal barrier dysfunction by regulating gut microbiota

Background

Hyperuricemia elevates gut permeability; however, the risk of its influence on the compromised intestinal barrier is poorly understood.

Aims

This study was carried out, aiming to elucidate the orchestrators and disruptors of intestinal barrier in hyperuricemia.

Methods

A mouse model of hyperuricemia was induced by administering adenine and oteracil potassium to mice. Allopurinol was used to decrease uric acid level, and antibiotics were administered to mice to deplete gut microbiota. Intestinal permeability was assessed using FITC-labeled dextran. Changes in gut microbial community were analyzed through 16S rRNA sequencing. IL-1β and TNF-α levels were quantified using ELISA. The expression of tight junction protein genes, TLR4, p65 and IL-1β, was determined with Q-PCR and Western blotting.

Results

Allopurinol treatment effectively reduced intestinal permeability and serum TNF-α levels. Antibiotic treatment alleviated but not abolished intestinal permeability. Uric acid alone was insufficient to increase Coca2 monolayer permeability. Allopurinol treatment altered microbial composition and suppressed opportunistic infections. Re-establishing hyperuricemia in a germfree mouse model protected mice from intestinal injury. Allopurinol and antibiotic treatments reduced TLR4 and IL-1β expressions, increased occludin and claudin-1 expressions but suppressed NF-ĸB p65 signaling. However, removing gut microbiota aggravated lipid metabolic dysfunction.

Conclusion

Gut microbiota is a direct and specific cause for intestinal barrier dysfunction.

Resveratrol Improves Hyperuricemia and Ameliorates Renal Injury by Modulating the Gut Microbiota

Resveratrol (RES) has been reported to prevent hyperuricemia (HUA); however, its effect on intestinal uric acid metabolism remains unclear. This study evaluated the impact of RES on intestinal uric acid metabolism in mice with HUA induced by a high-fat diet (HFD). Moreover, we revealed the underlying mechanism through metagenomics, fecal microbiota transplantation (FMT), and 16S ribosomal RNA analysis. We demonstrated that RES reduced the serum uric acid, creatinine, urea nitrogen, and urinary protein levels, and improved the glomerular atrophy, unclear renal tubule structure, fibrosis, and renal inflammation. The results also showed that RES increased intestinal uric acid degradation. RES significantly changed the intestinal flora composition of HFD-fed mice by enriching the beneficial bacteria that degrade uric acid, reducing harmful bacteria that promote inflammation, and improving microbial function via the upregulation of purine metabolism. The FMT results further showed that the intestinal microbiota is essential for the effect of RES on HUA, and that Lactobacillus may play a key role in this process. The present study demonstrated that RES alleviates HFD-induced HUA and renal injury by regulating the gut microbiota composition and the metabolism of uric acid.

Xiasangju alleviate metabolic syndrome by enhancing noradrenaline biosynthesis and activating brown adipose tissue

Metabolic syndrome (MetS) is a clinical condition associated with multiple metabolic risk factors leading to type 2 diabetes mellitus and other metabolic diseases. Recent evidence suggests that modulating adipose tissue to adaptive thermogenesis may offer therapeutic potential for MetS. Xiasangju (XSJ) is a marketed drug and dietary supplement used for the treatment of metabolic disease with anti-inflammatory activity. This study investigated the therapeutic effects of XSJ and the underlying mechanisms affecting the activation of brown adipose tissue (BAT) in MetS. The results revealed that XSJ ameliorated MetS by enhancing glucose and lipid metabolism, leading to reduced body weight and abdominal circumference, decreased adipose tissue and liver index, and improved blood glucose tolerance. XSJ administration stimulated catecholamine biosynthesis, increasing noradrenaline (NA) levels and activating NA-mediated proteins in BAT. Thus, BAT enhanced thermogenesis and oxidative phosphorylation (OXPHOS). Moreover, XSJ induced changes in gut microbiota composition, with an increase in Oscillibacter abundance and a decrease in Bilophila, Candidatus Stoquefichus, Holdemania, Parasutterella and Rothia. XSJ upregulated the proteins associated with intestinal tight junctions corresponding with lower serum lipopolysaccharide (LPS), tumor necrosis factor α (TNF-α) monocyte chemoattractant protein-1 (MCP-1) and interleukin-6 (IL-6) levels to maintain NA signaling transport. In summary, XSJ may alleviate MetS by promoting thermogenesis in BAT to ultimately boost energy metabolism through increasing NA biosynthesis, strengthening intestinal barrier integrity and reducing low-grade inflammation. These findings suggest XSJ has potential as a natural therapeutic agent for the treatment of MetS.