Chicory ameliorates hyperuricemia via modulating gut microbiota and alleviating LPS/TLR4 axis in quail

Skipjack Tuna (Katsuwonus pelamis) Dark Muscle Hydrolysate Ameliorates Hyperuricemia in Mice via Regulating Gut Microbiota and Serum Metabolism

Peptides have emerged as promising agents for ameliorating hyperuricemia (HUA), a condition that poses significant risks to human health. This study evaluated the HUA-alleviating potential of skipjack tuna dark muscle hydrolysate (STDH) in a mouse model of HUA induced by potassium oxonate (PO) and hypoxanthine (Hx). The results demonstrated elevated serum uric acid (SUA) levels, increased xanthine oxidase (XOD) activity in the serum and liver, and kidney and intestinal damage in HUA mice. Although the standard drug allopurinol (AP) effectively reduced SUA levels and lowered XOD activity in the serum and liver, it exacerbated kidney damage and caused significant weight loss. In contrast, STDH intervention not only significantly lowered SUA, serum creatinine (SCr), and blood urea nitrogen (BUN) levels but also inhibited XOD activity in serum and liver. Notably, STDH ameliorated renal and intestinal morphological damage, as evidenced by hematoxylin-eosin (HE) staining. Gut microbiome analysis further revealed that STDH normalized the HUA-associated elevation of the Bacteroidetes/Firmicutes ratio. Untargeted metabolomics identified STDH's regulatory effects on glycine, serine, and threonine metabolism; arginine and proline metabolism; and glycerophospholipid metabolism, with glutamine implicated as a key player in HUA pathogenesis. These findings demonstrate that STDH effectively alleviates HUA while avoiding adverse effects associated with conventional therapy, positioning it as a safe and cost-effective functional food candidate for HUA management.

Diacylglycerol from camellia oil improves hyperuricemia by inhibiting xanthine oxidase and modulating gut microbiota

Camellia oil exhibits multiple beneficial effects on cardiovascular, glucose, and lipid metabolism. However, the impact of camellia oil and diacylglycerol (DAG), which is one of the active compounds of camellia oil, is uncertain in terms of hyperuricemia (HUA). It was found that the physicochemical characterization of camellia oil and DAG shows a rich content of unsaturated fatty acids (UFA), particularly oleic acid and linoleic acid, thereby supporting their potential in treating HUA. In hyperuricemic mice, camellia oil and DAG dose-dependently reduced urine and serum uric acid (UA), serum creatinine, and xanthine oxidase (XOD) activity. High doses of camellia oil and DAG treatment dramatically reduced pro-inflammatory mediators in hyperuricemic mice's renal tissue, showing a dose-dependent reduction in hepatic XOD activity and inflammation. HUA may be treated by modulating gut flora with camellia oil and DAG. The alteration of Lactobacillus and Helicobacter abundance play key roles. PICRUSt2 functional prediction showed that phenylalanine, tyrosine, and tryptophan metabolic pathways may be mediated by camellia oil and DAG in HUA mice.

Gut microbiota as a new target for hyperuricemia: A perspective from natural plant products

BACKGROUND

Hyperuricemia, a prevalent chronic metabolic disorder caused by purine metabolism disturbances, is characterized by elevated serum uric acid (UA) levels. Prolonged hyperuricemia can cause severe complications such as gout or kidney damage. However, the toxic side effects of and adverse reactions to UA-lowering drugs are becoming increasingly prominent. Therefore, new targets and drugs for hyperuricemia are needed.

PURPOSE

This review aims to summarize recent research progress on the prevention and treatment mechanisms for gut microbiota-hyperuricemia from the perspective of plant-derived natural products.

METHODS

Data from PubMed, Web of Science, ScienceDirect, and the CNKI databases spanning from January 2020 to December 2024 were reviewed. The aim of this study is to categorize and summarize the relevant mechanisms through which natural products improve hyperuricemia via the gut microbiota. The retrieved data followed PRISMA criteria (Preferred Reporting Items for Systematic reviews and Meta-Analyses).

RESULTS

Regulating gut microbiota as a treatment for hyperuricemia. Targeting the gut microbiota could reduce host UA levels by promoting purine degradation, reducing UA production, and increasing UA excretion. Moreover, the gut microbiota also exerts anti-inflammatory and antioxidant effects that alleviate complications such as renal damage caused by hyperuricemia. Due to their diverse sources, multicomponent synergy, multitarget effects, and minimal side effects, plant-derived natural products have been extensively utilized in the management of hyperuricemia. Especially, utilizing natural products from plants to regulate the gut microbiota has become a new strategy for reducing UA levels.

CONCLUSION

This review comprehensively summarizes recent advances in understanding the preventive and therapeutic mechanisms of plant-derived natural products in ameliorating hyperuricemia and its comorbidities through gut microbiota modulation. This review contributes a novel perspective for the development of safer and more efficacious UA-lowering products.

Punicalagin attenuates hyperuricemia via restoring hyperuricemia-induced renal and intestinal dysfunctions

INTRODUCTION

It is estimated that 90% of hyperuricemia cases are attributed to the inability to excrete uric acid (UA). The two main organs in charge of excreting UA are the kidney (70%) and intestine (30%). Previous studies have reported that punicalagin (PU) could protect against kidney and intestinal damages, which makes it a potential candidate for alleviating hyperuricemia. However, the effects and deeper action mechanisms of PU for managing hyperuricemia are still unknown.

OBJECTIVE

To investigate the effect and action mechanisms of PU for ameliorating hyperuricemia.

METHODS

The effects and action mechanisms of PU on hyperuricemia were assessed using a hyperuricemia mice model. Phenotypic parameters, metabolomics analysis, and 16S rRNA sequencing were applied to explore the effect and fundamental action mechanisms inside the kidney and intestine of PU for improving hyperuricemia.

RESULTS

PU administration significantly decreased elevated serum uric acid (SUA) levels in hyperuricemia mice, and effectively alleviated the kidney and intestinal damage caused by hyperuricemia. In the kidney, PU down-regulated the expression of UA resorption protein URAT1 and GLUT9, while up-regulating the expression of UA excretion protein ABCG2 and OAT1 as mediated via the activation of MAKP/NF-κB in hyperuricemia mice. Additionally, PU attenuated renal glycometabolism disorder, which contributed to improving kidney dysfunction and inflammation. Similarly, PU increased UA excretion protein expression via inhibiting MAKP/NF-κB activation in the intestine of hyperuricemia mice. Furthermore, PU restored gut microbiota dysbiosis in hyperuricemia mice.

CONCLUSION

This research revealed the ameliorating impacts of PU on hyperuricemia by restoring kidney and intestine damage in hyperuricemia mice, and to be considered for the development of nutraceuticals used as UA-lowering agent.

Limosilactobacillus reuteri RE225 alleviates gout by modulating the TLR4/MyD88/NF-κB inflammatory pathway and the Nrf2/HO-1 oxidative stress pathway, and by regulating gut microbiota

BACKGROUND

Gout poses a significant health threat. The use of Lactobacillus from the gut microbiota is one potential remedy. However, the intricate molecular mechanisms governing the impact of Lactobacillus on gout remain largely uncharted. In this study, a strain of Limosilactobacillus reuteri RE225 was separated from the gut of mice and colitis was treated with polypeptide intervention.

RESULTS

Limosilactobacillus reuteri RE225 reduced foot tumefaction markedly in mice with gout and extended the pain threshold time in their feet. It also improved the health of gut microbiota. Intervention with L. reuteri RE225 also suppressed the TLR4/MyD88/NF-κB and nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathways in the mice, reduced the levels of pro-inflammatory cytokines - interleukin 1β (IL-1β), interleukin 6 (IL-6), and tumor necrosis factor-α (TNF-α) - and increased the level of the anti-inflammatory cytokine interleukin 10 (IL-10), thereby mitigating inflammation.

CONCLUSION

This study provides a theoretical basis for the comprehensive development of Limosilactobacillus reuteri and new ideas for the non-pharmacological treatment of gout. © 2024 Society of Chemical Industry.

Lacticaseibacillus casei JS-2 from 'Jiangshui' Reduces Uric Acid and Modulates Gut Microbiota in Hyperuricemia

Lacticaseibacillus casei (JS-2) is a novel probiotic isolated from "Jiangshui", a kind of traditional folk fermented food, which has a significant effect on hyperuricemia (HUA). In vitro experimental results showed that JS-2 has a high degradation ability and selectivity for uric acid (UA). The animal test results indicated that after two weeks of treatment, JS-2 could significantly reduce the level of UA in the serum of HUA quails (p < 0.01), and its effect is almost equivalent to that of the positive drug control group, benzbromarone. Further, after JS-2 treatment, the level of xanthine oxidase in quail serum decreased significantly. Analysis data of quail fecal metabolomics results showed that JS-2-altering metabolites were involved in amino acid, purine, and lipid metabolism. To investigate the mechanism underlying JS-2-mediated UA degradation in the quail model of HUA, 16S rRNA gene sequencing was conducted. It was found that the structure and function of the gut microbiota were restored after JS-2 intervention, and the abundance of short-chain fatty acid (SCFA)-producing bacteria (g__Ruminococcus_torques_group and g__Butyricicoccus) and bacteria with UA degradation capacity (g__unclassified_f__Lachnospiraceae and g__Negativibacillus) increased significantly; intestinal SCFAs, especially propionic acid, increased accordingly. These experimental data suggest that the beneficial effects of JS-2 may derive from changes in the gut microbiome, altering host-microbiota interactions, reducing UA levels by increasing UA excretion, and reducing absorption. These findings provided new evidence that JS-2 has the potential to be used as a naturally functional food for the prevention of HUA.

Progress in modeling avian hyperuricemia and gout (Review)

Human organ tissue is vulnerable to hyperuricemia (HUA), which negatively impacts quality of life, particularly when it progresses to gout. Chicken uric acid formation and metabolism are similar to human uric acid metabolism; therefore, theoretically, the genesis and progression of human HUA and gout may be similar to those of poultry models. The present review explored HUA and gout and the progress of poultry-induced HUA and gout models. The present study reviewed procedures of modelling chicken gout and HUA and the detection indices and current concerns regarding these models. Notably, In the production of poultry hyperuricemia model, the combined method of water and food induction has a higher success rate and stability. Compared with mice induced HUA and gout models, poultry induced HUA and gout models had less kidney damage, and the models were stable and long-lasting.

Imperata cylindrica polysaccharide ameliorates intestinal dysbiosis and damage in hyperuricemic nephropathy

In this study, a combination of adenine and potassium oxonate was utilized to establish a hyperuricemic nephropathy (HN) mouse model, aiming to elucidate the effect through which Imperata Cylindrica polysaccharide (ICPC-a) ameliorates HN. In HN mice, an elevation in the abundance of Erysipelatoclostridium, Enterococcus, Prevotella, and Escherichia-Shigella was observed, whereas Lactobacillus and Bifidobacterium declined. Additionally, the systemic reductions in the levels of acetate, propionate, and butyrate, along with a significant increase in indole content, were noted. HN mice demonstrated intestinal barrier impairment, as evidenced by diminished mRNA expression of ZO-1, Occludin, and Claudin-1 and increased Mmp-9 levels. The pro-inflammatory factors IL-6, IL-17, TNF-α, IFN-γ, and COX-2 were overexpressed. Subsequent gavage intervention with ICPC-a markedly mitigated the inflammatory response and ameliorated colon tissue damage. ICPC-a effectively regulated the abundance of gut microbiota and their metabolites, including short-chain fatty acids (SCFAs), bile acids (BAs), and indole, promoting the correction of metabolic and gut microbiota imbalances in HN mice. These findings underscored the capacity of ICPC-a as a prebiotic to modulate gut microbiota and microbial metabolites, thereby exerting a multi-pathway and multi-targeted therapeutic effect on HN.

Rutin, a natural flavonoid glycoside, ameliorates zearalenone induced liver inflammation via inhibiting lipopolysaccharide gut leakage and NF-κB signaling pathway in mice

Zearalenone (ZEN) poses a potential threat on human and animal health partly through the nuclear factor (NF)-κB signaling pathway. In silico study suggested that rutin effective against TLR4 and NF-κB. A wetting test was designed to evaluate the effect and underlying mechanism of rutin in alleviating ZEN-induced inflammation in animals. Twenty-four female mice were randomly divided into 4 groups: control (basal diet), ZEN group (basal diet + ZEN), rutin group (basic diet + rutin), Z + R group (basal diet + rutin + ZEN). Results showed that rutin effectively alleviated ZEN-induced inflammation and damage of liver and jejunum in mice. Rutin addition reduced the content of lipopolysaccharide (LPS) in serum and liver mainly by improving the intestinal barrier function resulted from the production increase of short-chain fatty acids (SCFA). In sum, this study showed that rutin alleviated ZEN-induced liver inflammation and injury by modulating the gut microbiota, increasing the production of SCFA and improving intestinal barrier function, leading to the decrease of LPS in liver and the inhibition of MyD88 independent NF-κB signaling pathway in mice. Specifically, these findings may provide useful insights into the screening of functional natural compounds and its action mechanism to alleviate ZEN induced liver inflammation.

Gut microecology: effective targets for natural products to modulate uric acid metabolism

Gut microecology,the complex community consisting of microorganisms and their microenvironments in the gastrointestinal tract, plays a vital role in maintaining overall health and regulating various physiological and pathological processes. Recent studies have highlighted the significant impact of gut microecology on the regulation of uric acid metabolism. Natural products, including monomers, extracts, and traditional Chinese medicine formulations derived from natural sources such as plants, animals, and microorganisms, have also been investigated for their potential role in modulating uric acid metabolism. According to research, The stability of gut microecology is a crucial link for natural products to maintain healthy uric acid metabolism and reduce hyperuricemia-related diseases. Herein, we review the recent advanced evidence revealing the bidirectional regulation between gut microecology and uric acid metabolism. And separately summarize the key evidence of natural extracts and herbal formulations in regulating both aspects. In addition,we elucidated the important mechanisms of natural products in regulating uric acid metabolism and secondary diseases through gut microecology, especially by modulating the composition of gut microbiota, gut mucosal barrier, inflammatory response, purine catalyzation, and associated transporters. This review may offer a novel insight into uric acid and its associated disorders management and highlight a perspective for exploring its potential therapeutic drugs from natural products.

Research progress of treating hyperuricemia in rats and mice with traditional Chinese medicine

Hyperuricemia (HUA) is a common chronic metabolic disease caused by abnormal purine metabolism and uric acid excretion. Despite extensive research on HUA, no clear treatment has been found so far. Improving purine metabolism and promoting uric acid excretion is crucial for the effective treatment of HUA. In recent years, traditional Chinese medicine and traditional Chinese medicine prescriptions have shown good effects in treating HUA. This article summarizes the latest progress in treating HUA in rats and mice using traditional Chinese medicine and prescriptions, elaborates on the pathogenesis of HUA, explores the application of commonly used traditional Chinese medicine treatment methods and prescriptions, and discusses the previous pharmacological mechanisms. In general, our research indicates that traditional Chinese medicine can effectively relieve the symptoms related to elevated uric acid levels in HUA rats and mice. However, further exploration and research are needed to verify its efficacy, safety, and feasibility.

Analyzing chemical composition of Sargentodoxae caulis water extract and their hypouricemia effect in hyperuricemic mice

Hyperuricemia (HUA) is a metabolic disease characterized by the increase of serum uric acid (UA) level. Sargentodoxae Caulis (SC) is a commonly used herbal medicine for the treatment of gouty arthritis, traumatic swelling, and rheumatic arthritis in clinic. In this study, a total of fifteen compounds were identified in SC water extract using UHPLC-Q-TOF-MS/MS, including three phenolic acids, seven phenolic glycosides, four organic acids, and one lignan. Then, to study the hypouricemia effect of SC, a HUA mouse model was induced using a combination of PO, HX, and 20% yeast feed. After 14 days of treatment with the SC water extract, the levels of serum UA, creatinine (CRE), blood urea nitrogen (BUN) were reduced significantly, and the organ indexes were restored, the xanthine oxidase (XOD) activity were inhibited as well. Meanwhile, SC water extract could ameliorate the pathological status of kidneys and intestine of HUA mice. Additionally, quantitative real-time PCR (qRT-PCR) and western blotting results showed that SC water extract could increase the expression of ATP binding cassette subfamily G member 2 (ABCG2), organic cation transporter 1 (OCT1), organic anion transporter 1 (OAT1) and organic anion transporter 3 (OAT3), whereas decrease the expression of glucose transporter 9 (GLUT9). This study provided a data support for the clinical application of SC in the treatment of HUA.

Fangyukangsuan granules ameliorate hyperuricemia and modulate gut microbiota in rats

Hyperuricaemia (HUA) is a metabolic disorder characterised by high blood uric acid (UA) levels; moreover, HUA severity is closely related to the gut microbiota. HUA is also a risk factor for renal damage, diabetes, hypertension, and dyslipidaemia; however, current treatments are associated with detrimental side effects. Alternatively, Fangyukangsuan granules are a natural product with UA-reducing properties. To examine their efficacy in HUA, the binding of small molecules in Fangyukangsuan granules to xanthine oxidase (XOD), a key factor in UA metabolism, was investigated via molecular simulation, and the effects of oral Fangyukangsuan granule administration on serum biochemical indices and intestinal microorganisms in HUA-model rats were examined. Overall, 24 small molecules in Fangyukangsuan granules could bind to XOD. Serum UA, creatinine, blood urea nitrogen, and XOD levels were decreased in rats treated with Fangyukangsuan granules compared to those in untreated HUA-model rats. Moreover, Fangyukangsuan granules restored the intestinal microbial structure in HUA-model rats. Functional analysis of the gut microbiota revealed decreased amino acid biosynthesis and increased fermentation of pyruvate into short-chain fatty acids in Fangyukangsuan granule-treated rats. Together, these findings demonstrate that Fangyukangsuan granules have anti-hyperuricaemic and regulatory effects on the gut microbiota and may be a therapeutic candidate for HUA.

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.

Hyperuricemia research progress in model construction and traditional Chinese medicine interventions

Hyperuricemia (HUA), a severe metabolic disease derived from purine metabolism disorder, will lead to abnormally increased serum uric acid (SUA) levels in the body. Studies have shown that HUA is highly related to gout, hypertension, diabetes, coronary heart disease, chronic kidney diseases, and so on. Traditional Chinese medicine (TCM) shows excellent results in treating HUA because of its unique advantages of multi-metabolites and multi-targets. This article reports on the use of TCM components for uric acid (UA)-lowering activity with excellent efficacy and low side effects based on established HUA models. This work summarizes the advantages and limitations of various HUA disease models for efficacy evaluation. Applications of TCM in HUA treatment have also been discussed in detail. This paper reveals recent research progress on HUA in constructing evaluation models and systematic TCM interventions. It will provide a scientific reference for establishing the HUA model and suggest future TCM-related HUA studies.

Si Miao San relieves hyperuricemia by regulating intestinal flora

This study seeks to investigate the therapeutic effects of Si Miao San (SMS) on hyperuricemia and its underlying mechanisms, particularly focusing on the role of intestinal flora. The key components of SMS were identified using high-performance liquid chromatography (HPLC). To establish a rat model of hyperuricemia, an intraperitoneal injection of potassium oxonate was performed, followed by oral administration of various concentrations of SMS. The study evaluated the status of hyperuricemia, renal pathology, xanthine oxidase (XO) activity, and intestinal flora. Utilizing HPLC, we identified five active components of SMS. Following SMS intervention, there was a significant reduction in serum levels of uric acid (UA), blood urea nitrogen, and creatinine, accompanied by an increase in urine UA levels in rats with hyperuricemia. Distinct pathological injuries were evident in the renal tissues of hyperuricemic rats, and these were partially alleviated following SMS intervention. Moreover, SMS exhibited a dose-dependent reduction in XO activity both in the serum and hepatic tissues. Notably, SMS contributed to an enhancement in the diversity of intestinal flora in hyperuricemic rats. The intervention of SMS resulted in a reduction in the abundance of certain bacterial species, including Parabacteroides johnsonii, Corynebacterium urealyticum, and Burkholderiales bacterium. This suggests that SMS may exert anti-hyperuricemia effects, potentially by modulating the composition of intestinal flora.

Models of gouty nephropathy: exploring disease mechanisms and identifying potential therapeutic targets

Gouty nephropathy (GN) is a metabolic disease with persistently elevated blood uric acid levels. The main manifestations of GN are crystalline kidney stones, chronic interstitial nephritis, and renal fibrosis. Understanding the mechanism of the occurrence and development of GN is crucial to the development of new drugs for prevention and treatment of GN. Currently, most studies exploring the pathogenesis of GN are primarily based on animal and cell models. Numerous studies have shown that inflammation, oxidative stress, and programmed cell death mediated by uric acid and sodium urate are involved in the pathogenesis of GN. In this article, we first review the mechanisms underlying the abnormal intrinsic immune activation and programmed cell death in GN and then describe the characteristics and methods used to develop animal and cell models of GN caused by elevated uric acid and deposited sodium urate crystals. Finally, we propose potential animal models for GN caused by abnormally high uric acid levels, thereby provide a reference for further investigating the methods and mechanisms of GN and developing better prevention and treatment strategies.

Gut-immunity-joint axis: a new therapeutic target for gouty arthritis

Gouty arthritis (GA) is an inflammatory disease characterized by pain. The primary goal of current treatment strategies during GA flares remains the reduction of inflammation and pain. Research suggests that the gut microbiota and microbial metabolites contribute to the modulation of the inflammatory mechanism associated with GA, particularly through their effect on macrophage polarization. The increasing understanding of the gut-joint axis emphasizes the importance of this interaction. The primary objective of this review is to summarize existing research on the gut-immune-joint axis in GA, aiming to enhance understanding of the intricate processes and pathogenic pathways associated with pain and inflammation in GA, as documented in the published literature. The refined comprehension of the gut-joint axis may potentially contribute to the future development of analgesic drugs targeting gut microbes for GA.

Disrupting the gut microbiota/metabolites axis by Di-(2-ethylhexyl) phthalate drives intestinal inflammation via AhR/NF-κB pathway in mice

Di-(2-ethylhexyl) phthalate (DEHP) is a widely used plasticizer known for its environmental endocrine-disrupting properties, posing potential risks to various organs. However, the precise impact of DEHP on intestinal health and its contribution to the initiation of intestinal inflammation remains elucidated. This study aims to investigate the underlying mechanisms of DEHP-induced intestinal inflammation in mice, specifically focusing on the complex interplay between the gut microbiota-metabolite axis and associated pathophysiological alterations. Our findings showed that DEHP-induced damage of multiple organs systemically, as indicated by abnormal liver and kidney biochemical markers, along with a disrupted ileum morphology. Additionally, DEHP exposure disrupted gut barrier function, causing intestinal inflammation characterized by bacterial translocation and alterations in defense and inflammation-related gene expressions. Moreover, 16S rRNA analysis suggested that DEHP-induced gut microbial remodeling is characterized by an upregulation of detrimental bacteria (Erysipelotrichaceae) and a downregulation of beneficial bacteria (Muribaculaceae, Ruminococcaceae, and Lachnospiraceae). Metabolomics analysis revealed DEHP perturbed gut metabolic homeostasis, particularly affecting the degradation of aromatic compounds, which generated an aberrant activation of the AhR and NF-κB, subsequently causing intestinal inflammation. Consequently, our results elucidate the mechanistic link between disrupted gut microbiota and metabolome and the initiation of DEHP-induced intestinal inflammation, mediated through the AhR/NF-κB signaling pathway.

Whey Protein Peptide Pro-Glu-Trp Ameliorates Hyperuricemia by Enhancing Intestinal Uric Acid Excretion, Modulating the Gut Microbiota, and Protecting the Intestinal Barrier in Rats

Hyperuricemia (HUA) is a metabolic disorder characterized by an increase in the concentrations of uric acid (UA) in the bloodstream, intricately linked to the onset and progression of numerous chronic diseases. The tripeptide Pro-Glu-Trp (PEW) was identified as a xanthine oxidase (XOD) inhibitory peptide derived from whey protein, which was previously shown to mitigate HUA by suppressing UA synthesis and enhancing renal UA excretion. However, the effects of PEW on the intestinal UA excretion pathway remain unclear. This study investigated the impact of PEW on alleviating HUA in rats from the perspective of intestinal UA transport, gut microbiota, and intestinal barrier. The results indicated that PEW inhibited the XOD activity in the serum, jejunum, and ileum, ameliorated intestinal morphology changes and oxidative stress, and upregulated the expression of ABCG2 and GLUT9 in the small intestine. PEW reversed gut microbiota dysbiosis by decreasing the abundance of harmful bacteria (e.g., Bacteroides, Alloprevotella, and Desulfovibrio) and increasing the abundance of beneficial microbes (e.g., Muribaculaceae, Lactobacillus, and Ruminococcus) and elevated the concentration of short-chain fatty acids. PEW upregulated the expression of occludin and ZO-1 and decreased serum IL-1β, IL-6, and TNF-α levels. Our findings suggested that PEW supplementation ameliorated HUA by enhancing intestinal UA excretion, modulating the gut microbiota, and restoring the intestinal barrier function.

Whey protein peptides PEW and LLW synergistically ameliorate hyperuricemia and modulate gut microbiota in potassium oxonate and hypoxanthine-induced hyperuricemic rats

Pro-Glu-Trp (PEW) and Leu-Leu-Trp (LLW) are peptides derived from whey protein digestive products; both peptides exhibit xanthine oxidase inhibitory activity in vitro. However, it remains unclear whether these peptides can alleviate hyperuricemia (HUA) in vivo. In this study, we investigated the roles of PEW and LLW, both individually and in combination, in alleviating HUA induced by potassium oxonate and hypoxanthine. Together, PEW and LLW exhibited synergistic effects in reducing the serum levels of uric acid (UA), creatinine, and blood urea nitrogen, as well as increasing the fractional excretion of UA. The combined treatment with PEW and LLW inhibited UA synthesis, promoted UA excretion, and restored renal oxidative stress and mitochondrial damage. Moreover, the combined treatment alleviated dysbiosis of the gut microbiota, characterized by increased helpful microbial abundance, decreased harmful bacterial abundance, and increased production of short-chain fatty acids. Taken together, these results indicate that the combination of PEW and LLW mitigate HUA and kidney injury by rebalancing UA synthesis and excretion, modulating gut microbiota composition, and improving oxidative stress.

Approaches to determine the efficiency of novel 3-phytase from Klebsiella pneumoniae and commercial phytase in broilers from 1 to 14 d of age

This study aimed to evaluate the effects of a laboratory 3-phytase (the expression of the phyK gene, Lab-Phy) and a commercial 6-phytase (Quantum Blue 40 P, Com-Phy) alone and in combination (corn-soy-based diets) in broilers. A total of 400, day-old Ross 308 male broilers were randomly assigned to 5 treatments with 10 replicate cages (8 chicks/cage) for a 14-day trial. Experimental treatments included the positive control (0.95% Ca and 0.48% nonphytate phosphorus (nPP), PC), negative control (0.90% Ca and 0.22% nPP, NC), and NC which was supplemented with Lab-Phy 250 FTU/kg and Com-Phy 250 FTU/kg alone or in combination of Lab-Phy 125 FTU/kg and Com-Phy 125 FTU/kg. The inclusion of Lab-Phy in the NC diet significantly improved the P and Ca content in the tibia compared to the NC group. Moreover, the inclusion of Com-Phy alone and in combination with Lab-Phy in the NC diet significantly increased the P and Ca content in the tibia compared to the Lab-Phy. The mRNA expression of NaPi-IIb was upregulated in the duodenum by the reduction of nPP and downregulated by the inclusion of any phytase, whereas other nutrient transporters were not influenced by the reduction of nPP or the addition of phytase in the small intestine mucosa. Broilers receiving the NC diet obtained the lowest body weight (BW) and body weight gain (BWG) at 8 to 14 and 1 to 14 d of age. The NC group showed the lowest villi height and surface area, Newcastle disease (ND) antibody titer, and digestibility of nutrients compared to the PC group at 14 d of age. Supplementing the NC diet with the Lab-Phy and Com-Phy individually, or in combination tended to improve BW, BWG, tibia characteristics, villi characteristics, ND, and retained CP and P, and apparent ileal digestibility of CP, P, methionine, and threonine. The present research indicated that the studied traits by the combination of phytases were slightly better than the average of the 2 individually, suggesting there might be some value in combining the laboratory and commercial phytases.

Quercetin-enriched Lactobacillus aviarius alleviates hyperuricemia by hydrolase-mediated degradation of purine nucleosides

The development of hyperuricemia (HUA) and gout is associated with dysbiosis of the gut microbiota. Quercetin can reduce serum uric acid levels and thus alleviate HUA by modulating the gut microbiota. However, the detailed mechanisms involved in this process are not fully understood. Here, we showed that quercetin significantly reduced the serum uric acid level in a chicken HUA model by altering the chicken cecal microbiota structure and function and increasing the abundance of Lactobacillus aviarius. An L. aviarius strain, CML180, was isolated from the quercetin-treated chicken gut microbiota. Strain characterization indicated that quercetin promoted the growth of L. aviarius CML180 and increased its adhesion, hydrophobicity, and co-aggregation abilities. Gavage of live L. aviarius CML180 to a mouse model of HUA-established by adenosine and potassium oxonate-reduced the serum uric acid level and alleviated HUA. The ability of L. aviarius CML180 to decrease the level of uric acid was due to its degradation of purine nucleosides, which are the precursors for uric acid production. A nucleoside hydrolase gene, nhy69, was identified from the genome of L. aviarius CML180, and the resulting protein, Nhy69, exhibited strong purine nucleoside-hydrolyzing activity at mesophilic temperature and neutral pH conditions. These findings provide mechanistic insights into the potential of quercetin to treat HUA or gout diseases via a specific gut microbe.

Influence of intestinal microecology in the development of gout or hyperuricemia and the potential therapeutic targets

Gout and hyperuricemia are common metabolic diseases. Patients with purine metabolism disorder and/or decreased uric acid excretion showed increased uric acid levels in the blood. The increase of uric acid in the blood leads to the deposition of urate crystals in tissues, joints, and kidneys, and causes gout. Recent studies have revealed that imbalance of the intestinal microecology is closely related to the occurrence and development of hyperuricemia and gout. Disorder of the intestinal flora often occurs in patients with gout, and high purine and high fructose may induce the disorder of intestinal flora. Short-chain fatty acids and endotoxins produced by intestinal bacteria are closely related to the inflammatory response of gout. This article summarizes the characteristics of intestinal microecology in patients or animal models with hyperuricemia or gout, and explores the relationship between intestinal microecology and gout or hyperuricemia from the aspect of the intestinal barrier, intestinal microorganisms, intestinal metabolites, and intestinal immune system. We also review the current status of hyperuricemia treatment by targeting intestinal microecology.

Jingfang granules ameliorate inflammation and immune disorders in mice exposed to low temperature and high humidity by restoring the dysregulation of gut microbiota and fecal metabolites

The dramatic changes in global climate on human health have been extremely severe. The immune disorder caused by low temperature and high humidity (LTHH) have become a severe public health issue. Clinically, Jingfang granule (JF) has the effect of dispelling cold and eliminating dampness, and is widely used in the treatment of cold caused by wind and cold, autoimmune diseases, and COVID-19 with cold-dampness stagnating in the lung pattern. Our study aims to elucidate the effect of JF on LTHH-induced immune disorders in mice as well as the underlying mechanisms. In this study, JF increased the spleen index, improved fecal character, repaired the intestinal barrier and alleviated intestinal inflammatory responses. Most importantly, JF ameliorated immune disorder in LTHH mice, which was manifested primarily by the significant increase in gdT, CD8+ Tcm, and CD8+ Tem cells, as well as the decrease in TH1, TH17, CD4+ Tem1, CD4+ Tem2, immature NK, mature NK cells, and M1-like macrophages. Interestingly, the JF treatment not only regulated the gut microbiota by decreasing the abundance of harmful bacteria, as well as up-regulating the abundance of beneficial bacteria, but also ameliorated the metabolic disorders by reversing the levels of fecal metabolites to normality. The results of the correlation analysis demonstrated a significant association among gut microbiota, fecal metabolites and immune cells. In addition, JF inhibited the TLR4/NF-κB/NLRP3 pathway in LTHH mice. In conclusion, our results suggested that JF alleviated inflammation and immune disorders in LTHH mice by restoring gut microbiota and fecal metabolism.

Research progress on the prevention and treatment of hyperuricemia by medicinal and edible plants and its bioactive components

Hyperuricemia is another common metabolic disease, which is considered to be closely related to the development of many chronic diseases, in addition to the "three highs." Currently, although drugs show positive therapeutic effects, they have been shown to produce side effects that can damage the body. There is growing evidence that medicinal and edible plants and their bioactive components have a significant effect on hyperuricemia. In this paper, we review common medicinal and edible plants with uric acid-lowering effects and summarize the uric acid-lowering mechanisms of different bioactive components. Specifically, the bioactive components are divided into five categories: flavonoids, phenolic acids, alkaloids, polysaccharides, and saponins. These active substances exhibit positive uric acid-lowering effects by inhibiting uric acid production, promoting uric acid excretion, and improving inflammation. Overall, this review examines the potential role of medicinal and edible plants and their bioactive components as a means of combating hyperuricemia, with the hope of providing some reference value for the treatment of hyperuricemia.

Corn Silk Flavonoids Ameliorate Hyperuricemia via PI3K/AKT/NF-κB Pathway

Hyperuricemia (HUA) is a widespread metabolic disease marked by an elevated level of uric acid, and is a risk factor for premature death. The protective effect of corn silk flavonoids (CSF) against HUA and its potential mechanisms were explored. Five important apoptosis and inflammation-related signaling pathways were identified by network pharmacological analysis. The CSF exhibited significant uric acid (UA)-lowering activity in vitro by decreasing xanthine oxidase (XOD) and increasing hypoxanthine-guanine phosphoribosyl transferase levels. In a potassium oxonate-induced HUA in vivo, CSF treatment effectively inhibited XOD activity and promoted UA excretion. Furthermore, it decreased the levels of TNF-α and IL-6 and restored pathological damage. In summary, CSF is a functional food component to improve HUA by reducing inflammation and apoptosis through the down-regulating PI3K/AKT/NF-κB pathway.

Exploring the role of gut microbiota dysbiosis in gout pathogenesis: a systematic review

Objectives

Gut dysbiosis is believed to be one of the several mechanisms that are involved in the pathogenesis of gout. This systematic review aimed to summarize the role of gut dysbiosis in gout disease and uncover the underlying mechanisms.

Methods

A comprehensive search was conducted on PubMed, Web of Science, and Scopus databases up to October 2021. Animal studies and human observational studies, including case-control, cross-sectional, and cohort studies assessing the association between gut microbiota composition and gout were included. The quality of included studies has been evaluated using the Newcastle-Ottawa Quality Assessment scale (NOS) and the SYRCLE's risk of bias tool.

Results

Initially, we found 274 studies among which 15 studies were included in this systematic review. Of them, 10 studies were conducted on humans and 5 studies were conducted on animals. Increased abundance of Alistipes and decreased abundance of Enterobacteriaceae alters purine metabolism, thereby aggravating gout condition. Moreover, a higher abundance of Phascolarctobacterium and Bacteroides in gout modulates enzymatic activity in purine metabolism. Butyrate-producing bacteria such as Faecalibacterium, prausnitzii, Oscillibacter, Butyricicoccus, and Bifidobacterium have higher abundance in healthy controls compared to gout patients, suggesting the anti-inflammatory and anti-microbial role of short-chain fatty acids (SCFAs). Lipopolysaccharides (LPS)-releasing bacteria, such as Enterobacteriaceae, Prevotella, and Bacteroides, are also involved in the pathogenesis of gout disease by stimulating the innate immune system.

Conclusion

Exploring the role of gut dysbiosis in gout and the underlying mechanisms can help develop microbiota-modulating therapies for gout.

Lactobacillus fermentum F40-4 ameliorates hyperuricemia by modulating the gut microbiota and alleviating inflammation in mice

Hyperuricemia (HUA) is a systemic disease characterized by a disorder of purine metabolism and an abnormal increase in the serum level of uric acid (UA). Probiotics can exert potential therapeutic benefits against some metabolic diseases by regulating the intestinal microbiota. Lactobacillus fermentum F40-4 with UA-lowering activity of 87.40% was screened using purine as the target in vitro. The UA-lowering activity of L. fermentum F40-4 was further explored in a mouse model of HUA in vivo. L. fermentum F40-4 could downregulate serum levels of UA, blood urea nitrogen, creatinine, and xanthine oxidase by 40.84%, 11.61%, 57.66%, and 41.79%, respectively. L. fermentum F40-4 restored organ damage, and adjusted enzyme activity and transporter expression to promote the metabolic level of UA. In addition, L. fermentum F40-4 could reshape the gut microbiota and suppress inflammation to ameliorate HUA. An increment in intestinal UA excretion was documented. These findings suggest that L. fermentum F40-4 might serve as a potential probiotic for the prevention and treatment of HUA.

Lactiplantibacillus pentosus P2020 protects the hyperuricemia and renal inflammation in mice

Introduction

Hyperuricemia (HUA) is a common metabolic disease, and its prevalence has been increasing worldwide. Pharmaceutical drugs have been used for controlling HUA but they all have certain side effects, which thus calls for discovering alternative options including using treatment of probiotics to prevent the development of HUA.

Methods

We established HUA mice model induced by potassium oxonate and adenine and performed in vivo experiments to verify the ability to lower serum uric acid of Lactiplantibacillus pentosus P2020 (LPP), a probiotics stain extracted from Chinese pickle. We also tried to discussed the underlying mechanisms.

Results

Oral administration with LPP significantly decreased serum uric acid and reduced renal inflammatory response by downregulating multiple inflammation pathways including NK-kB, MAPK, and TNFα. We also found that LPP administration significantly promoted uric acid excretion by regulating expression of transporters in the kidney and ileum. In addition, LPP intake improved intestinal barrier function and modulated the composition of gut microbiota.

Discussion

These results suggest that probiotics LPP may have a promising potential to protect against development of HUA and HUA-related renal damage, and its working mechanisms involve regulation of inflammation pathways and expression of transporters in the kidney and ileum.

Anti-Hyperuricemic Effect of Anserine Based on the Gut-Kidney Axis: Integrated Analysis of Metagenomics and Metabolomics

Nowadays, developing effective intervention substances for hyperuricemia has become a public health issue. Herein, the therapeutic ability of anserine, a bioactive peptide, was validated through a comprehensive multiomics analysis of a rat model of hyperuricemia. Anserine was observed to improve liver and kidney function and modulate urate-related transporter expressions in the kidneys. Urine metabolomics showed that 15 and 9 metabolites were significantly increased and decreased, respectively, in hyperuricemic rats after the anserine intervention. Key metabolites such as fructose, xylose, methionine, erythronic acid, glucaric acid, pipecolic acid and trans-ferulic acid were associated with ameliorating kidney injury. Additionally, anserine regularly changed the gut microbiota, thereby ameliorating purine metabolism abnormalities and alleviating inflammatory responses. The integrated multiomics analysis indicated that Saccharomyces, Parasutterella excrementihominis and Emergencia timonensis were strongly associated with key differential metabolites. Therefore, we propose that anserine improved hyperuricemia via the gut-kidney axis, highlighting its potential in preventing and treating hyperuricemia.

The toxicity of nano polyethylene terephthalate to mice: Intestinal obstruction, growth retardant, gut microbiota dysbiosis and lipid metabolism disorders

Polyethylene terephthalate (PET) are widely used in our daily life while they may be broken to smaller fractions as nano-sized PET (nPET) in the environment. The toxicity of nPET is still less studied. This work first evaluated the LD50 of different size of nPET (200 nm, S-nPET; 700 nm, B-nPET) in mice, then studied the health effects of single exposure to S/B-nPET at 200 mg/kg bw for 30 days. It was found that the LD50 was 266 mg/kg bw for S-nPET and 523 mg/kg bw for B-nPET, respectively, showing a size-dependent effect. S-nPET caused weight loss, cyst, intestinal obstruction, organ damage and mortality (40%), and perturbed gut microbiome and metabolome especially lipid metabolism, such as upregulated cholesterol, glycocholic, propionic acid, niacinamide, ectoine and xanthine, and downregulated arachidonic acid, anserine, histamine, while B-nPET did not. Serological analysis found S-nPET brought more lipid metabolic immune and neurological damage than B-nPET, confirming the size-dependent effect. To the best of our knowledge, this is the first report on the systematic toxicity of nPET to mice. Further studies are warranted for life-long effects of nPET. The protocol applied in this work may also be used for the study of the health effects of other plastics.

A Novel Approach Based on Gut Microbiota Analysis and Network Pharmacology to Explain the Mechanisms of Action of Cichorium intybus L. Formula in the Improvement of Hyperuricemic Nephropathy in Rats

Background

Cichorium intybus L. formula (CILF) is a traditional Chinese medicine (TCM) widely used in the treatment of gout and hyperuricemic nephropathy (HN). The aim of this research was to investigate the potential protective effect of CILF against HN and elucidated the underlying mechanism.

Methods

CILF water extract was administered to an HN rat model established by adenine combined with ethambutol. The levels of uric acid (UA), serum urea nitrogen (UREA), and creatinine (CREA) were detected. Changes in the pathology and histology of the kidney were observed by hematoxylin-eosin staining. The 16S rRNA of the gut microbiota was sequenced. The binding ability of the main ingredients of CILF to key targets was analyzed by network pharmacology and molecular docking. The expression levels of the related mRNAs and proteins in the kidney were evaluated by RT-qPCR and immunohistochemistry analysis.

Results

CILF administration significantly alleviated increases in UA, UREA, and CREA, structural damage, and kidney dysfunction. Gut microbiota analysis was applied to explore the pharmacological mechanism of the effects of CILF on bacterial diversity and microbiota structure in HN. CILF decreased the abundance of Bacteroides. In addition, it increased the abundance of Lactobacillaceae, Erysipelotrichaceae, Lachnospiraceae, Ruminococcaceae, and Bifidobacterium. Based on network pharmacology and molecular docking analysis, CILF profoundly influenced the IL17, TNF and AGE-RAGE signaling pathway. Additionally, CILF inhibited the expression of STAT3, VEGFA and SIRT1 to improve the symptoms of nephropathy. Our research suggested that CILF protects against kidney dysfunction in rats with HN induced by adenine combined with ethambutol.

Conclusion

Our findings on the anti-HN effects of CILF and its mechanism of action, from the viewpoint of systems biology, and elaborated that CILF can alter the diversity and community structure of the gut microbiota in HN, providing new approaches for the prevention and treatment of HN.

Ameliorative Effect of Mannuronate Oligosaccharides on Hyperuricemic Mice via Promoting Uric Acid Excretion and Modulating Gut Microbiota

Mannuronate oligosaccharide (MOS) is α-D-mannuronic acid polymer with 1,4-glycosidic linkages that possesses beneficial biological properties. The aim of this study was to investigate the hypouricemic effect of MOS in hyperuricemic mice and demonstrate the possible protective mechanisms involved. In this research, 200 mg/kg/day of MOS was orally administered to hyperuricemic mice for four weeks. The results showed that the MOS treatment significantly reduced the serum uric acid (SUA) level from 176.4 ± 7.9 μmol/L to 135.7 ± 10.9 μmol/L (p < 0.05). MOS alleviated the inflammatory response in the kidney. Moreover, MOS promoted uric acid excretion by regulating the protein levels of renal GLUT9, URAT1 and intestinal GLUT9, ABCG2. MOS modulated the gut microbiota in hyperuricemic mice and decreased the levels of Tyzzerella. In addition, research using antibiotic-induced pseudo-sterile mice demonstrated that the gut microbiota played a crucial role in reducing elevated serum uric acid of MOS in mice. In conclusion, MOS may be a potential candidate for alleviating HUA symptoms and regulating gut microbiota.

The Effects of Bacillus subtilis QST713 and β-mannanase on growth performance, intestinal barrier function, and the gut microbiota in weaned piglets

We investigated the effects of different Bacillus subtilis QST713 doses and a B. subtilis QST713 and β-mannanase mix on growth performance, intestinal barrier function, and gut microbiota in weaned piglets. In total, 320 healthy piglets were randomly assigned to four groups: 1) control group (basal diet), 2) BS100 group (basal diet plus 100 mg/kg B. subtilis QST713), 3) BS200 group (basal diet plus 200 mg/kg B. subtilis QST713), and 4) a BS100XT group (basal diet plus 100 mg/kg B. subtilis QST713 and 150 mg/kg β-mannanase). The study duration was 42 d. We showed that feed intake in weaned piglets on days 1 to 21 was increased in group BS100 (P < 0.05), and that the feed conversion ratio in group BS100XT animals decreased throughout the study (P < 0.05). In terms of microbial counts, the BS100XT group showed reduced Escherichia coli and Clostridium perfringens numbers on day 21 (P < 0.05). Moreover, no significant α-diversity differences were observed across all groups during the study (P > 0.05). However, principal coordinates analysis indicated clear separations in bacterial community structures across groups (analysis of similarities: P < 0.05) on days 21 and 42. Additionally, E-cadherin, occludin, and zonula occludens-1 (ZO-1) expression in piglet feces increased (P < 0.05) by adding B. subtilis QST713 and β-mannanase to diets. Notably, this addition decreased short-chain fatty acid concentrations. In conclusion, B. subtilis QST713 addition or combined B. subtilis QST713 plus β-mannanase effectively improved growth performance, intestinal barrier function, and microbial balance in weaned piglets.

Folic Acid Protects against Hyperuricemia in C57BL/6J Mice via Ameliorating Gut-Kidney Axis Dysfunction

Emerging lines of research evidence point to a vital role of gut-kidney axis in the development of hyperuricemia (HUA), which has been identified as an increasing burden worldwide due to the high prevalence. The involved crosstalk which links the metabolic and immune-related pathways is mainly responsible for maintaining the axial homeostasis of uric acid (UA) metabolism. Nowadays, the urate-lowering drugs only aim to treat acute gouty arthritis as a result of their controversial clinical application in HUA. In this study, we established the HUA model of C57BL/6J mice to evaluate the effectiveness of folic acid on UA metabolism and further explored the underlying mechanisms. Folic acid attenuated the kidney tissue injury and excretion dysfunction, as well as the typical fibrosis in HUA mice. Molecular docking results also revealed the structure-activity relationship of the folic acid metabolic unit and the UA transporters GLUT9 and URAT1, implying the potential interaction. Also, folic acid alleviated HUA-induced Th17/Treg imbalance and intestinal tissue damage and inhibited the active state of the TLR4/NF-κB signaling pathway, which is closely associated with the circulating LPS level caused by the impaired intestinal permeability. Furthermore, the changes of intestinal microecology induced by HUA were restored by folic acid, including the alteration in the structure and species composition of the gut microbiome community, and metabolite short-chain fatty acids. Collectively, this study revealed that folic acid intervention exerted improving effects on HUA by ameliorating gut-kidney axis dysfunction.

The role and mechanism of gut microbiota-derived short-chain fatty in the prevention and treatment of diabetic kidney disease

Diabetic kidney disease (DKD), an emerging global health issue, is one of the most severe microvascular complications derived from diabetes and a primary pathology contributing to end-stage renal disease. The currently available treatment provides only symptomatic relief and has failed to delay the progression of DKD into chronic kidney disease. Recently, multiple studies have proposed a strong link between intestinal dysbiosis and the occurrence of DKD. The gut microbiota-derived short-chain fatty acids (SCFAs) capable of regulating inflammation, oxidative stress, fibrosis, and energy metabolism have been considered versatile players in the prevention and treatment of DKD. However, the underlying molecular mechanism of the intervention of the gut microbiota-kidney axis in the development of DKD still remains to be explored. This review provides insight into the contributory role of gut microbiota-derived SCFAs in DKD.

Overnutrition-induced gout: An immune response to NLRP3 inflammasome dysregulation by XOD activity increased in quail

Background

Gout is a progressive metabolic disease closely related to hyperuricemia and urate deposition, with an increasing prevalence and incidence across the globe. Recent studies have shown that the pathological process of gout includes two stages: asymptomatic hyperuricemia and MSU crystal deposition. However, the immune response during the development of hyperuricemia to gouty arthritis is not fully elucidated.

Methods

Thus, an overnutrition-induced whole-course gout model was established to clarify the immune response and pathological changes in the development from hyperuricemia to gouty arthritis. The quails without urate oxidase were used as experimental animals. And we confirmed that uric acid metabolic targets were changed when quails were in the asymptomatic hyperuricemia stage.

Results

When the quail showed gout symptoms, the NLRP3 inflammasome was activated, and the expressions of IL-1β, TNF-α, IL-6, IL-8, and IL-18 were significantly increased. The relationship between the uric acid metabolism target and the NLRP3 inflammasome may be the critical immune response between hyperuricemia and gouty arthritis. Our data showed that, in the process of gout disease, the expression of xanthine oxidase (XOD) has been increasing, which increases the level of uric acid, disrupts the balance of oxidative stress, generates a large amount of ROS, activates the NLRP3 inflammasome, and release IL-1β. Treatment with the XOD inhibitor can reduce uric acid, restore the body's degree of peroxidative damage and antioxidant capacity, and inhibit NLRP3 inflammasome and IL-1β. In vitro, we extracted and identified primary fibroblast-like synoviocytes (FLS) from quail for the first time. Stimulating FLS with uric acid also caused ROS release and NLRP3 inflammasome activation. However, treatment with an XOD inhibitor prevented all these responses in FLS.

Conclusion

Our results indicate that the immune response between the uric acid metabolism target XOD and NLRP3 inflammasomes plays a crucial role in developing hyperuricemia to gouty arthritis, and inhibition of both XOD and NLRP3 inflammasomes may be an effective treatment for avoiding the development of asymptomatic hyperuricemia to MSU crystal deposition. Meanwhile, this study also provides an advantageous animal model for pathological mechanisms and research and development drugs for gout.

Integration of network pharmacology and intestinal flora to investigate the mechanism of action of Chinese herbal Cichorium intybus formula in attenuating adenine and ethambutol hydrochloride-induced hyperuricemic nephropathy in rats

CONTEXT

Cichorium intybus L. (Asteraceae) formula (CF) has been applied as a folk medicine to treat hyperuricemic nephropathy (HN). However, the exact mechanism remains unclear.

OBJECTIVE

To explore the therapeutic effect and mechanism of CF on HN.

MATERIALS AND METHODS

Through network pharmacological methods, the targets of the active component of CF against HN were obtained. Subsequently, Male Wistar rats were divided into control, HN, allopurinol (50 mg/kg), CF high-dose (8.64 g/kg) and CF low-dose (2.16 g/kg) groups. The HN model was induced via intragastric administration of adenine (100 mg/kg) and ethambutol hydrochloride (250 mg/kg) for 3 weeks. After CF treatment, biochemical indicators including UA, UREA and CREA were measured. Then, HE staining, qRT-PCR and gut microbiota analysis were conducted to further explore the mechanism.

RESULTS

The network pharmacology identified 83 key targets, 6 core genes and 200 signalling pathways involved in the treatment of HN. Compared to the HN group, CF (8.64 g/kg) significantly reduced the levels of UA, UREA and CREA (from 2.4 to 1.57 μMol/L, from 15.87 to 11.05 mMol/L and from 64.83 to 54.83 μMol/L, respectively), and mitigated renal damage. Furthermore, CF inhibited the expression of IL-6, TP53, TNF and JUN. It also altered the composition of gut microbiota, and ameliorated HN by increasing the relative abundance of some probiotics.

CONCLUSIONS

This work elucidated the therapeutic effect and underlying mechanism by which CF protects against HN from the view of the biodiversity of the intestinal flora, thus providing a scientific basis for the usage of CF.

The role of gut microbiota in gout: Is gut microbiota a potential target for gout treatment

Numerous studies have demonstrated that gut microbiota is essential for the host's health because it regulates the host's metabolism, endocrine, and immune systems. In recent years, increasing evidence has shown that gut microbiota plays a role in the onset and progression of gout. Changes in the composition and metabolism of the gut microbiota, result in abnormalities of uric acid degradation, increasing uric acid generation, releasing pro-inflammatory mediators, and intestinal barrier damage in developing gout. As a result, gout therapy that targets gut microbiota has drawn significant interest. This review summarized how the gut microbiota contributes to the pathophysiology of gout and how gout affects the gut microbiota. Additionally, this study explained how gut microbiota might serve as a unique index for the diagnosis of gout and how conventional gout treatment medicines interact with it. Finally, prospective therapeutic approaches focusing on gut microbiota for the prevention and treatment of gout were highlighted, which may represent a future avenue in gout treatment.

Brussels Chicory Stabilizes Unstable Atherosclerotic Plaques and Reshapes the Gut Microbiota in Apoe-/- Mice

BACKGROUND

Adherence to a Mediterranean dietary pattern can protect against atherosclerosis in part by reducing intestinal permeability and gut microbial LPS production. Brussels chicory, a typical Mediterranean vegetable, has been shown to inhibit the formation of early-stage atherosclerosis in mice.

OBJECTIVES

We evaluated whether Brussels chicory affects advanced atherosclerosis progression, intestinal permeability, and gut microbial LPS production.

METHODS

Thirty-week-old male apoE-deficient mice with unstable atherosclerotic plaques in the brachiocephalic artery were fed the AIN-93G diet alone (control) or supplemented with 0.5% freeze-dried Brussels chicory for 20 wk. Plaque volume and features of plaque stability, plaque macrophage polarization, fecal and serum LPS concentrations, serum lipid profiles and inflammation-related cytokines, and gut microbial profiles were measured.

RESULTS

Compared with the control treatment, Brussels chicory consumption did not significantly change plaque volume and serum lipid profiles. However, it increased plaque stability (P < 0.05), as evidenced by reduced necrotic core size (42.3%), and increased fibrous cap thickness (55.0%) and collagen content (68.4%). Moreover, Brussels chicory consumption reduced intestinal permeability (56.3%), fecal and serum LPS concentrations (52.2% and 39.4%), serum IL1β and TNFα (52.0% and 33.8%), promoted plaque macrophage polarization towards the M2-like phenotype, and altered gut microbial composition, the latter indicated by increased relative abundance of certain members of the Ruminococcaceae family, such as Ruminiclostridium_9, Ruminiclostridium_5, and Intestinimonas (P < 0.05). Spearman correlation analyses further showed that these bacterial genera were significantly correlated with intestinal permeability, fecal and serum LPS, serum proinflammatory cytokines, and several features of plaque stability.

CONCLUSIONS

Brussels chicory might help stabilize atherosclerotic plaques in mice by reducing intestinal permeability and gut microbial LPS production. This study provides a promising approach to slow the progression of atherosclerosis.

Gut microbiota changes and biological mechanism in hepatocellular carcinoma after transarterial chemoembolization treatment

Background and aims

Intestinal flora is closely associated with the occurrence and development of hepatocellular carcinoma (HCC). However, gut microbial changes and biological mechanisms in HCC after transarterial chemoembolization (TACE) treatment are rarely reported.

Methods

We evaluated changes in intestinal flora after TACE in rabbit HCC models and assessed the impact of these changes on the disease. Twenty-four rabbit VX2 HCC models were established and intestinal flora structures, intestinal barrier function, changes in blood lipopolysaccharide (LPS) levels, Toll-like receptor 4 (TLR4), Cyclooxygenase-2 (COX-2), and p-signal transducer and activator of transcription 3(p-STAT3) protein expression levels were studied after TACE treatment.

Results

Compared with healthy rabbits, the intestinal flora in HCC models exhibited structural changes; intestinal barrier function was decreased, and increased LPS levels entered the circulation. A short-term follow-up after TACE showed the procedure partially reversed the intestinal microflora disorder caused by the tumor: intestinal barrier and liver functions were improved, intestinal LPS levels in the blood were reduced, and liver metabolism toward LPS was enhanced. Correlation analyses of the first 75 significantly changed bacteria with clinical factors showed that harmful bacteria had decreased and beneficial bacteria increased. Blood LPS levels and downstream signaling molecule TLR4, COX-2, and p-STAT3 protein expression levels were reduced, which correlated with tumor drug resistance and invasion capabilities.

Conclusions

We first characterized gut microbiota changes and biological mechanisms in HCC after TACE treatment. Our data provide a theoretical research basis for TACE combined with an intestinal flora intervention and systemic chemotherapy.

Xanthine oxidase inhibitory study of eight structurally diverse phenolic compounds

This project was designed to explore the xanthine oxidase (XO) inhibitory mechanism of eight structurally diverse phenolic compounds [quercetin: C1, quercetin-3-rhamnoside: C2, 4, 5-O-dicaffeoylquinic acid: C3, 3, 5-O-dicaffeoylquinic acid: C4, 3, 4-O-di-caffeoylquinic acid: C5, 4-O-caffeoylquinic acid (C6), 3-O-caffeoylquinic acid: C7, and caffeic acid: C8]. For this purpose, in-vitro and different computational methods were applied to determine the xanthine oxidase (XO) inhibitory potential of eight structurally diverse phenolic compounds. The results revealed that phenolic compounds (C1–C8) possess strong to weak XO inhibitory activity. These results were further confirmed by atomic force microscopy (AFM) and ¹H NMR analysis. Furthermore, computational study results revealed that phenolic compounds (C1–C8) bind with the surrounding amino acids of XO at the molybdenum (MO) site. These in-vitro and in-silico results divulge that phenolic compounds have a strong potential to lower uric acid levels via interacting with the XO enzyme and can be used to combat hyperuricemia.

Melatonin mitigates aflatoxin B1-induced liver injury via modulation of gut microbiota/intestinal FXR/liver TLR4 signaling axis in mice

Aflatoxin B1 (AFB1) is a widespread contaminant in foods and feedstuffs, and its target organ is the liver. Melatonin (MT) has been shown to alleviate inflammation in organs and remodel gut microbiota in animals and humans. However, the underlying mechanism by which MT alleviates AFB1-induced liver injury remains unclear. In the present study, MT pretreatment markedly increased the expression of intestinal tight junction proteins (ZO-1, Occludin, and Claudin-1), decreased intestinal permeability, reduced production of gut-derived Lipopolysaccharide (LPS) and remodeled gut microbiota, ultimately alleviated AFB1-induced liver injury in mice. Interestingly, MT pretreatment failed to exert beneficial effects on the intestine and liver in antibiotic-treated mice. Meanwhile, MT pretreatment significantly increased the farnesoid X receptor (FXR) protein expression of ileum, and decreased the TLR4/NF-κB signaling pathway-related messenger RNA (mRNA) and proteins (TLR4, MyD88, p-p65, and p-IκBα) expression in livers of AFB1-exposed mice. Subsequently, pretreatment by Gly-β-MCA, an intestine-selective FXR inhibitor, blocked the alleviating effect of MT on liver injury through increasing the liver-specific expression of TLR4/NF-κB signaling pathway-related mRNA and proteins (TLR4, MyD88, p-p65, and p-IκBα). In conclusion, MT pretreatment ameliorated AFB1-induced liver injury and the potential mechanism may be related to regulate gut microbiota/intestinal FXR/liver TLR4 signaling axis, which provides a strong evidence for the protection of gut-derived liver inflammation.

Gut microbiota remodeling: A promising therapeutic strategy to confront hyperuricemia and gout

The incidence of hyperuricemia (HUA) and gout continuously increases and has become a major public health problem. The gut microbiota, which colonizes the human intestine, has a mutually beneficial and symbiotic relationship with the host and plays a vital role in the host's metabolism and immune regulation. Structural changes or imbalance in the gut microbiota could cause metabolic disorders and participate in the synthesis of purine-metabolizing enzymes and the release of inflammatory cytokines, which is closely related to the occurrence and development of the metabolic immune disease HUA and gout. The gut microbiota as an entry point to explore the pathogenesis of HUA and gout has become a new research hotspot. This review summarizes the characteristics of the gut microbiota in patients with HUA and gout. Meanwhile, the influence of different dietary structures on the gut microbiota, the effect of the gut microbiota on purine and uric acid metabolism, and the internal relationship between the gut microbiota and metabolic endotoxemia/inflammatory factors are explored. Moreover, the intervention effects of probiotics, prebiotics, and fecal microbial transplantation on HUA and gout are also systematically reviewed to provide a gut flora solution for the prevention and treatment of related diseases.

The abundance of bifidobacterium in relation to visceral obesity and serum uric acid

Gut microbiome has been shown to play a role in the development of obesity in recent studies. Most of these studies on obesity were based on the BMI classification criteria, which doesn't distinguish Visceral adipose tissue (VAT) from subcutaneous adipose tissue (SAT). Some studies showed that VAT has a higher risk of inducing metabolic diseases than SAT. This study focused on the visceral obesity defined by increased visceral fat area. The present study was designed to investigate the association of visceral obesity with gut predominant microbiota and metabolic status. This study included 372 healthy individuals from medical examination center in Shulan Hangzhou Hospital. Quantitative polymerase chain reaction (q-PCR) technique was used to detect ten kinds of gut predominant bacteria in fresh feces. Visceral fat area (VFA) was measured by the bioimpedance analyzer (INBODY720, Korea). The abundance of Bifidobacterium significantly decreased in the visceral obesity group. Compared with the lean group, Visceral obesity group had significantly higher levels of LDL, TG, FBG, serum uric acid (SUA) and lower levels of HDL. SUA was an independent impact factor for Bifidobacterium. SUA was negatively correlated with Bifidobacterium and positively correlated with VFA. In the mediation analysis, SUA showed significant mediation effect. SUA may be a mediating factor between decreased Bifidobacterium and increased VAT.

Folic acid and zinc improve hyperuricemia by altering the gut microbiota of rats with high-purine diet-induced hyperuricemia

A high-purine diet can cause hyperuricemia and destroy the microbial composition of the gut microbiota. Both folic acid and zinc significantly reduce uric acid levels and alleviate hyperuricemia. However, whether the underlying mechanisms are associated with the regulation of the gut microbiota remain unknown. To explore alterations of the gut microbiota related to folic acid and zinc treatment in rats with hyperuricemia in our study. A hyperuricemic rat model was established with a high-purine diet. The effects of folic acid and zinc on uric acid levels were evaluated. Alterations of the gut microbiota related to hyperuricemia and the treatments were evaluated by sequencing using the Illumina MiSeq system. The results demonstrated that uric acid levels dropped observably, and the activities of adenosine deaminase (ADA) and xanthine oxidase (XOD) were downregulated after folic acid or zinc intervention. 16S rRNA gene sequencing-based gut microbiota analysis revealed that folic acid and zinc enhanced the abundance of probiotic bacteria and reduced that of pathogenic bacteria, thus improving intestinal barrier function. PICRUST analysis indicated that folic acid and zinc restored gut microbiota metabolism. These findings indicate that folic acid and zinc ameliorate hyperuricemia by inhibiting uric acid biosynthesis and stimulating uric acid excretion by modulating the gut microbiota. Thus, folic acid and zinc may be new and safe therapeutic agents to improve hyperuricemia.

Study effect of probiotics and prebiotics on treatment of OVA-LPS-induced of allergic asthma inflammation and pneumonia by regulating the TLR4/NF-kB signaling pathway

Asthma is a common respiratory disease, and immune system dysregulation has direct relevance to asthma pathogenesis. Probiotics and prebiotics have immunomodulatory effects and can regulate immune responses and may attenuate allergic reactions. Therefore, in this study, we explored the role of probiotics and prebiotics in regulating acute airway inflammation and the TLR4/NF-kB pathway. Allergic asthma model of BALB/c mice was produced and treated with probiotics (LA-5, GG, and BB-12) and prebiotics (FOS and GOS). Then AHR, BALF cells count, EPO activity, IL-4, 5, 13, 17, 25, 33, as well as IFN-γ, total and OVA-specific IgE, IgG1, Cys-LT, LTB4, LTC4, and TSLP levels were measured. Also, the GTP/GOT assay was performed and gene expression of Akt, NLR3, NF-kB, PI3K, MyD88, TLR4, CCL11, CCL24, MUC5a, Eotaxin, IL-38, and IL-8 were determined. Finally, lung histopathological features were evaluated. Treatment with probiotics could control AHR, eosinophil infiltration to the BALF and reduce the levels of immunoglobulins, IL-17, GTP and also decrease mucus secretion, goblet cell hyperplasia, peribronchial and perivascular inflammation and also, EPO activity. It could reduce gene expression of TLR4 and CCL11. On the other hand, IL-38 gene expression was increased by both probiotic and prebiotic treatment. Treatment with probiotics and prebiotics could control levels of IL-4, 5, 13, 25, 33, leukotrienes, the gene expression of AKT, NLR3, NF-κB, MyD88, MUC5a. The prebiotic treatment could control peribronchial inflammation and PI3K gene expression. Both of the treatments had no significant effect on the GOT, TSLP and IL-8, eotaxin and CCL24 gene expression. Probiotics and prebiotics could induce tolerance in allegro-inflammatory reactions and alter immune responses in allergic conditions. Probiotics could also modulate cellular and humoral immune responses and prevent allergic disorders.