Gout

Rutin ameliorates gout via reducing XOD activity, inhibiting ROS production and NLRP3 inflammasome activation in quail

Gout is a metabolic disease affected by monosodium urate (MSU) deposition, which is directly related to hyperuricemia. Recent reports on the prevalence and incidence of gout have been widely circulated worldwide. Currently, the anti-gout drugs in clinical practice are mainly small-molecule synthetic drugs, and the effectiveness and safety are limited. Reducing uric acid and inhibiting inflammation are the focused areas of drug research and development on gout. Rutin, a natural flavonoid, has been reported to alleviate inflammation in various diseases. However, whether rutin exerts protective effects on gout remains to be elucidated. This study used quails without urate oxidase as experimental animals to induce endogenous gout models through a high purine diet. We confirmed that quail in the model group developed gout symptoms at 30 days of the experiment. And the targets of uric acid metabolism, oxidative stress level, and NLRP3 inflammasome were dysregulated in quails. Rutin treatment improves gout and reduces inflammatory expression in quail. We further confirmed that rutin treatment reduced XOD activity and uric acid levels in quail. And rutin inhibited ROS production, restored oxidative stress balance, inhibited NLRP3 inflammasome activation, and exerted anti-inflammatory effects. We extracted and identified the fibroblast-like synoviocytes (FLS) for the first time. The results showed that rutin could reduce ROS production and NLRP3 inflammasome activation of FLS after uric acid stimulation. In conclusion, our findings underscore that rutin may be a gout protective agent by reducing XOD activity, inhibiting ROS production and NLRP3 inflammasome activation. Meanwhile, this study also provides an available animal model for the research drugs of gout.

Two a posteriori dietary patterns are associated with risks of hyperuricemia among adults in less-developed multiethnic regions in Southwest China

Diet is a major determinant of hyperuricemia, but little is known about the association between diet and hyperuricemia in less-developed multiethnic regions (LMERs). This study aimed to assess the hypothesis that dietary patterns (including 2 a-priori and 3 a posteriori dietary patterns) are associated with hyperuricemia in LMERs. The 2 a priori dietary patterns were the Dietary Approaches to Stop Hypertension (DASH) and the alternative Mediterranean diet (aMED). We derived 3 a posteriori dietary patterns from the China Multi-Ethnic Cohort study by principal component factor analysis. Given that those dietary patterns had high geographic discrimination, they were named the Sichuan Basin (economically developed industrial region), Yunnan-Guizhou Plateau (agricultural region), and Qinghai-Tibet Plateau (nomadic region) dietary pattern, respectively. We performed a logistic regression model to investigate associations between dietary patterns and hyperuricemia with potential confounders identified by the directed acyclic graph. Comparing the highest with the lowest quintiles, the Sichuan Basin dietary pattern was positively associated with hyperuricemia, whereas the Yunnan-Guizhou Plateau dietary pattern showed an inverse association with hyperuricemia. For the Qinghai-Tibet Plateau dietary pattern, DASH, or aMED, our results did not show a significant association with hyperuricemia. The results were robust among stratified analyses and different analyzing strategies. The dietary patterns showed great diversity in Southwest China. Both DASH and aMED, which many studies widely recommended, did not show expected beneficial effects on preventing hyperuricemia. However, the plant-based protein dietary pattern in the Yunnan-Guizhou Plateau showed a beneficial association with the risk of hyperuricemia, which can provide insights for dietary guidance in LMERs.

Hydromethanolic Root Extract of Gnidia Kraussiana Demonstrates Anti-Inflammatory Effect Through Anti-Oxidant Activity Enhancement in a Rodent Model of Gout

Gout is a metabolic arthritis that originates from increased accumulation of monosodium urate (MSU) crystals in joints. This work aimed to evaluate the antioxidant and anti-inflammatory activities of the hydromethanolic extract of Gnidia kraussiana (HEGK) using model of Gouty arthritis on mice. The total polyphenol, flavonoid, tannin content and the antioxidant activity of HEGK were also evaluated. MSU-injected mice were treated daily for 3 days with HEGK (25, 50 and 100 mg/kg). Indomethacin and colchicin were used as reference drugs. Paw oedema and body temperature were measured at different time intervals post-injection. Malondialdehyde, acid phosphatase, β-Galactosidase, catalase, superoxide dismutase and glutathione levels were evaluated. HEGK is rich in polyphenol (129.93 mg/100 g), flavonoid (67.78 mg/100 g) and tannin conferring it a high antioxidant activity. Acute oral toxicity of HEGK resulted in LD50 greater than 2000 mg/kg. Oral administration of HEGK induced a significant decrease in the oedema of legs injected with urate crystals and reduced the release of acid phosphatase and β-Galactosidase. A model of oxidative damage was successfully established, revealing a significant increase in malondialdehyde and inhibition of antioxidants, including superoxide dismutase, catalase and glutathione activity. Thus, HEGK can actively inhibit the effect of inflammatory mediators in gouty arthritis.

Global status and trends in gout research from 2012 to 2021: a bibliometric and visual analysis

BACKGROUND

Gout is the most common inflammatory arthritis with an increasing prevalence and incidence across the globe. We aimed to provide a comprehensive and systematic knowledge map of gout research to determine its current status and trends over the past decade.

METHODS

Publications on gout research were obtained from the Web of Science Core Collection (WOSCC) database. Bibliometric R, VOSviewer, and Citespace were employed to analyze the eligible literature.

RESULTS

A total of 5535 publications concerning gout research between 2012 and 2021 were included. Most publications and citations both numerically came from China. The strongest international cooperation belonged to the USA. The University of Auckland was the most productive institution with a leading place in research collaboration. The prime funding agency was the National Natural Science Foundation of China. Most papers were published in Clinical Rheumatology. Annals of the Rheumatic Diseases achieved the highest number of citations, H-index and IF, which showed the most excellent comprehensive strength. The individual author with the most paper authorship was Dalbeth Nicola with 241 publications and 46 H-index. Keywords and co-citation analysis discovered that pathological mechanism remains the future hotspot in gout research. It may involve gout connection with gut microbiota, NLRP3 inflammasome, xanthine oxidase, and urate-transporter ABCG2. In addition, besides metabolic diseases, the relationship between gout and heart failure may need more attention.

CONCLUSION

This study clarified the current status and research frontier in gout over the past decade, which would provide valuable research references for later researchers. Key Points •We disclosed the current status and frontier directions of gout over the past 10 years worldwide. •We identified future hotspots of gout research, including gout connection with gut microbiota, NLRP3 inflammasome, xanthine oxidase, and urate-transporter ABCG2. •We discovered that the relationship between gout and heart status would be the research frontier.

Effectiveness and safety of anakinra in gouty arthritis: A case series and review of the literature

Background

Gout is the most common type of inflammatory arthritis. Nonsteroidal anti-inflammatory drugs, corticosteroids, and colchicine are the first-line agents, although they are contraindicated in many patients. Blockade of IL-1 with anakinra can be an alternative.

Objective

To present a case series of 10 difficult-to-treat gout patients treated with anakinra and perform a scoping review of the effectiveness and safety of anakinra in gout patients.

Methods

A total of 1,519 citations were screened. The reviewers ran a two-stage screening process by title/abstract and full-text reading. Thirty-eight articles finally met the selection criteria and were included for data extraction and synthesis. Experience in difficult-to treat and complex clinical scenarios, such as active infection, hemodialysis, and transplantation, were specifically described.

Results

The study sample comprised 551 patients, from whom 648 flares were finally analyzed. The mean age was 57.9 years, and 82.9% were men. The clinical presentation was polyarticular in 47.5% and tophaceous in 66.9%. Sixty-five patients with an active infection, 41 transplanted patients and 14 in haemodyalisis treated with anakinra are described. More than half of the patients had >1 associated comorbidity. Anakinra was effective both for flares (94%) and for long-term treatment (91%) and well tolerated. In the case of flares, 34 (6.7%) adverse effects were registered. Adverse events were more prevalent in long-term treatment.

Conclusion

Anakinra was effective and safe for management of gout flares in difficult-to-treat patients. It has been used in multiple complex scenarios, such as active infections, dialysis, transplantation, chronic kidney disease, and polyarticular gout. Anakinra has also proven effective as long-term treatment, although there are more concerns about its safety.

Expression Profile of Pyroptosis-Related Genes and the Associated Regulatory Axis in Primary Gout Patients

Purpose

Analyzed the expression characteristics of pyroptosis-related genes (PRGs) in peripheral blood mononuclear cells (PBMCs) of gout patients by microarray, and constructed ceRNA network to explore the molecular mechanism of RNA-mediated pyroptosis regulation.

Patients and Methods

Human mRNA, lncRNA, circRNA microarray data were used to identify differentially expressed in PBMCs from patients with primary gout and healthy controls. Differential PRGs in PBMCs of gout patients identified by Genecard database and mRNA microarray data. GO and KEGG enrichment analyses of these genes were then conducted. Protein-protein interaction networks and cytoHubba were used to identify hub genes. Combining the lncRNA and circRNA microarray data, a ceRNA network was constructed by Cytoscape to screen out key non-coding RNA molecules that can regulate target PRGs. Finally, the relative expression levels of target miRNA and circRNA in 60 gout patients and 40 healthy subjects were detected by qRT-PCR.

Results

The results revealed 30 differentially expressed PRGs. GO and KEGG analysis of these genes were mainly concentrated in the production and regulation of cytokines, NOD-like receptor signaling pathway and so on. Nine hub genes were screened by PPI network, including IL1B, DDX3X, NLRP3, NLRP9, AIM2, CASP8, P2XR7, CARD8 and IFI16. The has_circRNA_102906\hsa_circRNA_102910\hsa_circRNA_102911-hsa-miR-129-5p-DDX3X\NLRP3\NLRP9 regulatory network was constructed. The expression of has_circRNA_102906, hsa_circRNA_102910, hsa_circRNA_102911 were up-regulated and hsa-miR-129-5p down-regulated in PBMCs of gout patients. The relative expression of hsa_circRNA_102911 was positively correlated with clinical inflammatory indicators associated with gout, and the area under the curve of hsa_circRNA_102911 for gout diagnosis was 0.85 (95% CI: 0.775-0.925; p < 0.001).

Conclusion

There are several differentially expressed PRGs in PBMCs of gout patients, which are involved in the regulation of gout inflammation through multiple pathways. hsa_circRNA_102911-hsa-miR-129-5p-DDX3X\NLRP3\NLRP9 may be the key regulatory pathway for pyroptosis to regulate gout inflammation, and hsa_circRNA_102911 may be a potential biomarker for the diagnosis of primary gout.

Changes of serum uric acid level during acute gout flare and related factors

OBJECTIVE

By studying the changes of serum uric acid (SUA) in acute stage and remission stage of gouty arthritis, we aimed to explore the relationship between the changes of SUA level and free glucocorticoids and inflammatory factors.

METHODS

A prospective, longitudinal study was conducted on 50 acute gout patients in the dedicated gout clinic of the Affiliated Hospital of Qingdao University. Blood and 24-hour urine samples were collected during the acute phase and two weeks after the initial visit. Patients with acute gouty arthritis were treated primarily with colchicine and nonsteroidal anti-inflammatory drugs.

RESULTS

A total of 32 patients completed the two-week follow-up trial. SUA levels were significantly downregulated during the acute flare than after the flare (464.14 ± 90.97 vs. 527.36 ± 86.90 μmol/L, p < 0.001). The 24-hour fractional excretion of uric acid (24 h FEur) (5.54 ± 2.82% vs. 4.68 ± 2.83%, p < 0.001) and 24-hour urinary uric acid excretion (24 h Uur) (663.08 ± 249.48 μmol/L vs. 540.87 ± 263.18 μmol/L, p = 0.001) increased significantly in patients during the acute phase. The percent change in SUA was associated with those in 24 h FEur and C-reactive protein. Meanwhile, the percent change in 24 h Uur was associated with those in 24-hour urinary free cortisol, percent change in interleukin 1β and interleukin 6.

CONCLUSION

Decreased SUA level during the acute gout flare was associated with increased excretion of urinary uric acid. Inflammatory factors and bioactive free glucocorticoids may play significant roles in this process.

Oxyberberrubine, a novel liver microsomes-mediated secondary metabolite of berberine, alleviates hyperuricemic nephropathy in mice

BACKGROUND

Berberrubine (BRB), one of the major metabolites of berberine (BBR), exerts an anti-hyperuricemic effect even superior to BBR. Liver is an important location for drug transformation. Nevertheless, there are few studies on the bioactivities and metabolites of BRB.

PURPOSE

We investigated whether oxyberberrubine (OBR), a liver metabolite of BRB, exerted urate-lowering and reno-protective effects in hyperuricemic mice.

METHODS

Liver microsomes were used to incubate BRB for studying its biotransformation. We isolated and identified its new metabolite OBR, and investigated its anti-hyperuricemic and reno-protective effects. In this work, the hyperuricemic mice model was established by receiving potassium oxonate (PO) and hypoxanthine (HX) for 7 consecutive days. 1 h after modeling, different dosages of OBR (5, 10 and 20 mg/kg), BRB (20 mg/kg) or febuxostat (Fex, 5 mg/kg) were given mice by gavage.

RESULTS

Results showed that OBR possessed potent anti-hyperuricemic and reno-protective effects in hyperuricemic mice. Serum uric acid (UA) level was lowered, and the activities of xanthine oxidase (XOD) as well as adenosine deaminase (ADA) in the liver were suppressed after treatment with OBR. Hepatic expressions of XOD were remarkably decreased at mRNA and protein levels by OBR treatment. In addition, OBR prominently alleviated renal injury, embodied in markedly reduced serum creatinine and blood urea nitrogen (BUN) levels, decreased inflammatory mediators (TNF-α, IL-1β, IL-6 and IL-18) levels, mRNA expression of CYP27B1 and repairment of renal tissues damage. Besides, OBR down-regulated renal expression of urate transporter 1 (URAT1), glucose transporter 9 (GLUT9), NOD-like receptor 3 (NLRP3), apoptosis-associated speck-like protein containing CARD (ASC), and caspase-1 at mRNA and protein levels.

CONCLUSIONS

In short, our study indicated that OBR possessed superior anti-hyperuricemic and reno-protective effects, at least in part, through the inhibition of XOD, URAT1, GLUT9 and NLRP3 inflammasome signaling pathway in the kidney.

Lipidomics analysis facilitate insight into the molecular mechanisms of urate nephropathy in a gout model induced by combination of MSU crystals injection and high-fat diet feeding

Renal injury is one of the most common clinical manifestations of patients with hyperuricaemia/gout. The precise pathophysiological mechanism(s) for the renal injury is still unknown. Furthermore, it is also unclear whether the clinical therapies (e.g., colchicine and febuxostat) could prevent its progression or not. Lipids are involved in almost all of important biological processes and play critical roles in maintaining the renal functions. Herein, shotgun lipidomics was performed for class-targeted lipid analysis of cellular lipidomes in renal tissue of a gouty model induced by combination of monosodium urate crystals injection and high-fat diet feeding with/without treatment with either colchicine or febuxostat. Serum uric acid (UA), proinflammatory cytokines (i.e., TNF-α and IL-6), xanthine oxidase activity, footpad swelling, and pain threshold were determined to evaluate the gouty severity. Renal histopathological changes, blood urea nitrogen, creatinine, and kidney index were used to reflect renal injury. Lipidomics analysis revealed that altered triacylglycerol (TAG) profile, impaired mitochondrial function resulted by decreased tetra 18:2 cardiolipin, reduced 4-hydroxyalkenal (HNE) species, and elevated lysophospholipids were already present in the kidneys at early stage of renal injury, probably contributing to its occurrence and development. In addition to significantly reduce the UA level and relief the gouty severity, treatment with either colchicine or febuxostat could restore HNE bioavailability, thereby delaying the progression of renal injury. However, both of them could not recover the altered TAG profile and the impaired mitochondrial function, indicating that treatment with either of them could not completely prevent the development of renal injury in the gouty model.

Effect of Berberine on Activation of TLR4-NFκB Signaling Pathway and NLRP3 Inflammasome in Patients with Gout

OBJECTIVE

To determine the effects of berberine (BBR) on the activation of toll-like receptor 4 (TLR4), nuclear factor (NF)κB (NF-κB) signaling and NLRP3 inflammasome in patients with gout.

METHODS

Peripheral blood mononuclear cells (PBMCs) were obtained from 24 acute (AP) and 41 non-acute (NAP) phases of primary gout patients, respectively, as well as 30 healthy controls (HC). TLR4, NF-κB (p65), NLRP3, apoptosis-associated specklike protein containing a CARD (PYCARD), cysteinyl aspartate specific proteinase-1 (CASP1), and interleukin-1β (IL-1β) mRNA expression levels in PBMCs were measured by quantitative reverse transcriptase polymerase chain reaction. The protein levels of TLR4, myeloid differentiation factor 88 (MyD88), NF-κB (p50/65), inhibitor of kappa B kinase α/β (IKKα/β), NF-κB inhibitor α (IKBα), phospho-IKKα/β (p-IKKα/β), NLRP3, PYCARD, and CASP1 were monitored by Western blotting. Serum IL-1β protein level was measured using enzyme-linked immunosorbent assay (ELISA). In addition, PBMCs from HC and macrophages derived from a spontaneously immortalized monocyte-like cell line (THP-1) were stimulated using monosodium urate (MSU, 100 µg/mL), 0.1% dimethyl sulfoxide, 25 µmol/L BBR, and 10, 25, and 50 µmol/L BBR+100 µg/mL MSU for different time periods. The protein levels of IL-1β and IL-18 in cell culture supernatants was measured by ELISA, and the protein expressions of TLR4, MyD88, NF-κB (p50/p65), IKKα/β, I κBβ, p-IKKα/β, NLRP3, PYCARD, and CASP1 in macrophages were analyzed by Western blotting.

RESULTS

(1) TLR4, NF-κB (p65), PYCARD, CASP1, and IL-1β mRNA levels in PBMCs were significantly higher in the AP group than in the HC group (P<0.05). The NLRP3 mRNA expression levels in PBMCs were found to be significantly lower in the AP and NAP groups than in the HC group (P<0.05, P<0.01). (2) The protein levels of TLR4, IKKβ, MyD88, NF-κB, p-IKKα/β, PYCARD, and CASP1 in PBMCs were significantly higher, and those of IκBα, IKKα, and NLRP3 were found to be significantly lower in the AP group than in the HC group (P<0.05 or P<0.01). (3) The serum IL-1β protein levels were significantly higher in the AP and NAP groups than in the HC group (P<0.01). (4) The IL-1β protein level was significantly lower in the culture supernatants of the PBMCs stimulated with MSU for 3 and 6 h in the 25 and 50 µmoL/L BBR groups compared with that in the MSU group (P<0.01). (5) The protein levels of IL-1β and IL-18 were also significantly lower in the culture supernatants of macrophages stimulated with MSU for 3 and 6 h in BBR groups compared with those in the MSU group (P<0.01). (6) The protein levels of TLR4, MyD88, NF-κB (p50, p65, p105), IKKα/β, p-IκBα, p-IKKα/β, PYCARD, and CASP1 were significantly differed between the macrophages stimulated with MSU for 0.5 and 6 h in BBR groups compared with those in the MSU group (P<0.05 or P<0.01).

CONCLUSIONS

Activation of TLR4-NFκB signaling and NLRP3 inflammasome by MSU crystals drives the progression of gout inflammation. BBR ameliorates gouty inflammation, which is mechanistically associated with its regulation of TLR4-NF-κB signaling and NLRP3 inflammasome expression.

Single-cell RNA sequencing of immune cells in patients with acute gout

Cell subpopulations in the blood and joint fluid of patients with gout are poorly understood. Single-cell RNA sequencing and bioinformatic tools were used to identify cell subsets and their gene signatures in blood and synovial fluid (SF) cells, determine their relationships, characterize the diversity, and evaluate interactions among specific cell types. We identified 34 subpopulations (5 types of B cells, 16 types of T and natural killer cells, 9 types of monocytes, and 4 other cell types) in the blood of five healthy subjects and seven patients with acute gouty, and the SF of three patients with acute gout. We found that naïve CD4 T cells and classical monocytes cell populations were enriched in patients with gout, whereas plasmacytoid dendritic cells and intermediate monocytes were more abundant in healthy subjects. SF was enriched in Th1/Th17 cells, effector memory CD8 T cells, mucosal-associated invariant T cells, and macrophages. Subclusters of these cell subpopulations showed different compositions between healthy subjects and those with acute gout, according to blood and SF samples. At the cellular level, the inflammation score of a subpopulation or subcluster was highest in SF, following by the blood of acute gout patients and healthy person, whereas energy score showed the opposite trend. We also detected specific cell-cell interactions for interleukin-1, tumor necrosis factor-α, and transforming growth factor-β1 expression in the cells of patients with acute gout. Our study reveals cellular and molecular insights on inflammatory responses to hyperuricemia or uric crystal and may provide therapeutic guidance to improve treatments for gout.

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.

Isolation and Pathogenicity of a Novel Goose Astrovirus from Overfed Adult Landaise Geese in China

Goose astrovirus (GAstV) is an important pathogen causing visceral gout and high mortality in goslings, which has broken out and spread across China. In 2021, a disease characterized by urate deposition on the visceral surface and 30% mortality occurred in commercial adult Landaise geese in Zhejiang Province, China. A systematic study identified an infecting astrovirus, designated ZJCX, that was efficiently isolated from a diseased goose with a chicken hepatocellular carcinoma cell line (LMH). In contrast to other GAstVs originating from goslings, ZJCX caused cytopathogenic effects in LMH cells, and the crystalline arrangement of viral particles was observed through transmission electron microscopy. Indeed, phylogenetic analysis and nucleotide homology comparison revealed that ZJCX isolate belongs to the genotype II cluster of GAstVs and displays 97.8-98.4% identity with other GAstV II strains. However, several specific mutations occurred in the polyprotein and capsid protein regions. Moreover, a pathogenicity assessment of ZJCX with a gosling model was conducted, and typical visceral gout was reproduced and led to 18% mortality. The viral loads of ZJCX in the blood, kidney, and liver were detected with specific primers after inoculation, which demonstrated that the kidney and liver presented viral loads peaking at seven days post-inoculation (dpi). Biochemical parameter examination showed that AST, ALT, γ-GT, UA, and BUN levels were significantly increased by GAstV, whereas body weight was reduced. Overall, this study indicated that the GAstV isolate could infect adult geese, and the results regarding the viral loads and biochemical parameters induced by ZJCX provide insight into GAstV pathogenicity.

Infected nasal gout tophus: A case report

Gout is a common form of inflammatory arthritis, characterized by the deposition of monosodium urate crystals. If chronically present and not adequately treated by serum urate reducers, gout tophi can develop at various locations. Here, we report the first infected gout tophus at the septal cartilage and nasal tip.

Lifestyle and Symptom Risk Factors for Dry Eye Disease in Asian Gout Population: A Population-Based Case-Control Study

We aim to investigate the lifestyle and symptom factors related to dry eye disease (DED) presence in patients with persistent gout using the Taiwan Biobank (TWB) database. A retrospective case-control study was conducted, and patients with a history of gout longer than 10 years were enrolled in the persistent-gout group. Each persistent-gout patient was age- and sex-matched to two non-gout individuals who served as the control group, and we included a total of 973 and 1946 patients in the persistent-gout group and non-gout groups. The main outcome of our study is the presence of DED and the distribution of several lifestyle and symptom risk factors of DED in persistent-gout and non-gout individuals. Logistic regression considering the age and sex and interaction test was applied to estimate the correlation of each lifestyle and symptom risk factor to DED in the two groups. A total of 95 and 140 DED events were found in the persistent-gout and non-gout groups, with a significantly higher percentage in the persistent-gout population (aOR: 1.167, 95% CI: 1.073-3.855, p = 0.0415). The visual display terminal (VDT) user (p = 0.0026) and persistent alcohol drinking (p = 0.0384) were associated with DED more often in the persistent-gout population than the non-gout population. Moreover, the percentages of DED in the patients with gout intervals of 10-20 years and more than 20 years were statistically insignificant (aOR: 1.042, 95% CI: 0.886-1.910, p = 0.5279). In conclusion, VDT usage and persistent alcohol drinking are prominent lifestyle and symptom risk factors for DED occurrence in patients who have experienced gout for more than 10 years.

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.

Superiority of Low-Dose Benzbromarone to Low-Dose Febuxostat in a Prospective, Randomized Comparative Effectiveness Trial in Gout Patients With Renal Uric Acid Underexcretion

OBJECTIVE

The predominant mechanism driving hyperuricemia in gout is renal uric acid underexcretion; however, the standard urate-lowering therapy (ULT) recommendation is first-line xanthine oxidase inhibitor (XOI), irrespective of the cause of hyperuricemia. This comparative effectiveness clinical trial was undertaken to compare first-line nontitrated low-dose benzbromarone (LDBen) uricosuric therapy to XOI ULT with low-dose febuxostat (LDFeb) in gout patients with renal uric acid underexcretion.

METHODS

We conducted a prospective, randomized, single-center, open-label trial in men with gout and renal uric acid underexcretion (defined as fractional excretion of urate <5.5% and uric acid excretion ≤600 mg/day/1.73 m2 ). A total of 196 participants were randomly assigned to receive LDBen 25 mg daily or LDFeb 20 mg daily for 12 weeks. All participants received daily urine alkalization with oral sodium bicarbonate. The primary end point was the rate of achieving the serum urate target of <6 mg/dl.

RESULTS

More participants in the LDBen group achieved the serum urate target than those in the LDFeb group (61% compared to 32%, P < 0.001). Rates of adverse events, including gout flares and urolithiasis, did not differ between groups, with the exception of greater transaminase elevation in the LDFeb group (4% for LDBen compared to 15% for LDFeb, P = 0.008).

CONCLUSION

Compared to LDFeb, LDBen has superior urate-lowering efficacy and similar safety in treating relatively young and healthy patients with renal uric acid underexcretion-type gout.

Characteristic alterations of gut microbiota in uncontrolled gout

Microbiome research has been on the rise recently for a more in-depth understanding of gout. Meanwhile, there is a need to understand the gut microbiome related to uric acid-lowering drug resistance. In this study, 16S rRNA gene-based microbiota analysis was performed for a total of 65 stool samples from 17 healthy controls and 48 febuxostat-treated gout patients (including 28 controlled subjects with decreased uric acid levels and 20 uncontrolled subjects with non-reduced uric acid levels). Alpha diversity of bacterial community decreased in the healthy control, controlled, and uncontrolled groups. In the case of beta diversity, the bacterial community was significantly different among groups (healthy control, controlled, and uncontrolled groups). Taxonomic biomarker analysis revealed the increased population of g-Bifidobacterium in healthy controls and g-Prevotella in uncontrolled patients. PCR further confirmed this result at the species level. Additionally, functional metagenomics predictions led to the exploration of various functional biomarkers, including purine metabolism. The results of this study can serve as a basis for developing potential new strategies for diagnosing and treating gout from microbiome prospects.

Network pharmacology and in vivo experiments reveal the pharmacological effects and molecular mechanisms of Simiao Powder in prevention and treatment for gout

Background

Gout is a common disease with high incidence due to unhealthy diet and living habits. Simiao Powder, as a classic formula consisted of four common herbs, has been widely used in clinical practice since ancient times to prevent and treat gout. However, the pharmacological mechanism of Simiao Powder is still unclear.

Methods

Based on network pharmacology, Simiao Powder active compounds were identified in TCMSP, ETCM and BATMAN database, used to establish a network of interaction between potential targets of Simiao Powder and known therapeutic targets of gout. Subsequently, the key potential targets are being used for protein–protein interaction, GO enrichment analysis and KEGG pathway enrichment analysis through several authoritative open databases. Molecular docking through AutoDockTools software can verify interaction between molecules. Finally, to validate the predicted results, in vivo experiments based on hyperuricemic-gout mice model were designed and treated with Simiao powder and allopurinol. Serum levels of uric acid (UA), creatinine (Cr), blood urea nitrogen (BUN) and xanthine oxidase (XOD) were determined using a customized assay kit while the expression of PPAR-γ, PTGS1, IL-6 and Bcl2 mRNA were analyzed through qRT-PCR.

Results

Disease-target-compound network was visualized basing on the 20 bioactive compounds and the 19 potential targets using Cytoscape software. The results of PPI analysis, GO enrichment and KEGG pathway enrichment analysis indicate that the potential mechanism of Simiao Powder in treating gout may be achieved by regulating immune and inflammatory reactions, improving metabolism and endocrine. The results of molecular docking show that most of the targets and components have good binding activity. In vivo experiments revealed that Simiao powder can decreased serum UA and XOD levels in hyperuricemic-gout mice, and improved renal function. Furthermore, Simiao powder certainly regulates the expression of PPAR-γ, PTGS1, IL-6 and Bcl2 mRNA in ankle tissue in hyperuricemic-gout mice.

Conclusion

Collectively, this research predicted a multiple compounds, targets, and pathways model mechanism of Simiao Powder in the prevention and treatment of gout, providing new ideas and methods for in-depth research, via vivo experiments.

Retrospective longitudinal assessment of ultrasound gout lesions using the OMERACT semi-quantitative scoring system

OBJECTIVES

The objectives of this study were (i) to evaluate the responsiveness of gout-specific US lesions representing urate deposition in patients receiving treat-to-target urate-lowering therapy using a binary and the OMERACT-defined semi-quantitative scoring systems; (ii) to determine the most responsive US measure for urate deposition and the optimal joint/tendon set for monitoring this.

METHODS

US (28 joints, 14 tendons) was performed in microscopically verified gout patients initiating/increasing urate-lowering therapy and repeated after 6 and 12 months. Static images/videos of pathologies were stored and scored binarily and semi-quantitatively for tophus, double contour sign (DC) and aggregates. Lesion scores were calculated at patient level, as were combined crystal sum scores. Responsiveness of lesions-scored binarily and semi-quantitatively-was calculated at both patient and joint/tendon levels.

RESULTS

Sixty-three patients underwent longitudinal evaluation. The static images/videos assessed retrospectively showed statistically significant decreases in tophus and DC, when scored binarily and semi-quantitatively, whereas aggregates were almost unchanged during follow-up. The responsiveness of the semi-quantitative tophus and DC sum scores were markedly higher than when using binary scoring. The most responsive measure for urate deposition was a combined semi-quantitative tophus-DC-sum score. A feasible joint/tendon set for monitoring included knee and first-second MTP joints and peroneus and distal patella tendons (all bilateral), representing the most prevalent and responsive sites.

CONCLUSION

The OMERACT consensus-based semi-quantitative US gout scoring system showed longitudinal validity with both tophus and DC being highly responsive to treatment when assessed in static images/videos. A responsive US measure for urate deposition and a feasible joint/tendon set for monitoring were proposed and may prove valuable in future longitudinal studies.

Dose-response meta-analysis on urate, gout, and the risk for Parkinson's disease

The relationship between Parkinson's disease (PD) and urate or gout has attracted significant interest in recent years, but the results were conflicting. This dose-response meta-analysis aimed to estimate the correlation between urate levels or gout and the risk for PD. The Embase, PubMed, and Medline databases were searched for studies that investigated the relationship between the risk for PD and urate levels or gout. Random-effects or fixed-effects models were used to obtain pooled relative risks (RRs) and corresponding 95% confidence intervals (CIs). Fifteen studies, involving 449,816 participants and 14,687 cases in total, were included in the meta-analysis. High serum urate levels were associated with decreased risk for PD (RR 0.44 [95% CI 0.32-0.55]). Subgroup analysis according to sex revealed a neuroprotective effect of high urate levels against PD among females (0.68 [95% CI 0.43-0.93]) and males (0.49 [95% CI 0.34-0.64]). The risk for PD was lowered by 6% (0.94 [95% CI 0.90-0.98]) for each 1 mg/dl increase in serum urate level and reduced by 13% (0.87 [95% CI 0.80-0.95]) with each 2 mg/dl increase in serum urate level. However, gout was not closely correlated with the risk for PD (0.97 [95% CI 0.85-1.09]). Higher serum urate levels reduced the risk for PD, which was decreased by 6% (relative risk reduction) for each 1 mg/dl increase in serum urate levels. And the results indicated that urate may exert protective effects against the development of PD.

Recent progress and perspectives on the relationship between hyperuricemia and periodontitis

Periodontitis is one of the most prevalent diseases in oral cavity, which could not merely lead to the destruction of supporting or surrounding tooth structures but also affect the whole-body health such as the digestive and nervous systems. Epidemiological investigations suggested that in some developed countries, more than 45% or even 50% population were suffering from periodontitis. However, the prevalence increases with age remarkably and it is investigated that a high prevalence (>50%) is affecting the elderly who is over 65 years old. There is an increasing interest in the direct and indirect relationships between periodontitis and hyperuricemia. Currently, hyperuricemia has become the second major metabolic disease in modern society and the prevalence of hyperuricemia among adult males and females was 21.7% and 14.4% respectively. As an inflammatory disease associated with various systemic diseases, periodontitis may have certain connections with hyperuricemia. Partial existing research announced that hyperuricemia could act as an inhibitory factor for periodontitis, while other scholars presented that a high uric acid (UA) level was more likely to aggravate inflammatory immune response and lead to more serious tissue destruction. This article provides a detailed and comprehensive overview of the relationship underlying hyperuricemia and periodontitis in the molecular mechanisms. Given the impact of hyperuricemia, this review could provide insight into its comorbidities.

Fufang Zhenzhu Tiaozhi capsule ameliorates hyperuricemic nephropathy by inhibition of PI3K/AKT/NF-κB pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Excessive serum uric acid (SUA) causes hyperuricemic nephropathy (HN), characterized by inflammatory infiltration and tubulointerstitial fibrosis. Most recently, we demonstrated that Fufang Zhenzhu Tiaozhi (FTZ) capsule attenuated diabetic nephropathy through inhibition of renal inflammation and fibrosis. However, whether FTZ ameliorates HN is still unclear.

AIM OF THE STUDY

To determine the protective roles and mechanism of FTZ in mouse renal injury and fibrosis under hyperuricemic condition.

MATERIALS AND METHODS

HN mice, induced by potassium oxonate and hypoxanthine, were administrated with 600 and 1200 mg/kg FTZ (intragastrically) daily for three weeks. SUA levels, renal functions and histological changes were analyzed. Western blotting, quantitative real-time PCR (q-PCR) and RNA sequencing were used to identify the roles and underlying mechanism of FTZ in HN mice.

RESULTS

We demonstrated that FTZ treatment mitigated renal injury in mice, as evidenced by the decrease in SUA, serum creatinine (SCr) and cystatin C (Cys C) levels, as well as improved renal histology. FTZ markedly attenuates inflammasome activation, collagen deposition and the imbalance of uric acid transporters. RNA-sequencing revealed a key mechanism involved in the protective effects on HN mice was related to PI3K/AKT/NF-κB pathway. Western blot also confirmed that FTZ diminished the phosphorylation of AKT and p65 in HN mice.

CONCLUSIONS

FTZ prevents renal injury, inflammation and fibrosis in HN mice via promoting uric acid excretion and inhibiting PI3K/AKT/NF-κB signaling pathway.

Integrating network pharmacology and experimental validation to clarify the anti-hyperuricemia mechanism of cortex phellodendri in mice

Hyperuricemia (HUA), a common metabolic disease, is treated as the second-largest metabolic disease after diabetes in China. Cortex Phellodendri (CP) is one of the most frequently used herbal medicines for treating gout or HUA. However, the mechanism underlying the anti-HUA effect of CP is still unrevealed. Hence, this study aimed to explore the pharmacological mechanism of CP against HUA using network pharmacology coupled with in vivo experimental validation. Active compounds and potential targets of CP, as well as the potential targets related to HUA, were retrieved from multiple open-source databases. The drug-disease overlapping targets were obtained by Venn diagram analysis and used to construct the herb-component-target (HCT), protein-protein-interaction (PPI), and component-target-pathway (CTP) networks. The functional enrichment analysis was also performed for further study. Furthermore, a HUA mouse model was induced by a combination of intraperitoneal injection of potassium oxonate (PO, 300 mg/kg) and intragastric administration of hypoxanthine (HX, 300 mg/kg) daily for 10 days. Different dosages of CP (200, 400, and 800 mg/kg) were orally given to mice 1 h after modeling. The results showed that 12 bioactive compounds and 122 drug-disease overlapping targets were obtained by matching 415 CP-related targets and 679 HUA-related targets, and berberine was one of the most important compounds with the highest degree value. The core targets of CP for treating HUA were TP53, MAPK8, MAPK3, IL-6, c-Jun, AKT1, xanthine oxidase (XOD), and ATP-binding cassette subfamily G member 2 (ABCG2). The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment results showed that the anti-HUA effect of CP mainly involved the pathways of inflammation and apoptosis, such as PI3K/Akt, TNF, MAPK, TLR, AMPK, NF-κB, and NLRP3 signaling pathways. In vivo animal experiment further confirmed the hypouricemic effect of CP in a HUA mouse model, as evidenced by significantly restored kidney histological deteriorations, and considerably decreased levels of serum uric acid (sUA), creatinine (Cre), blood urea nitrogen (BUN), and hepatic UA. Furthermore, the hypouricemic action of CP in vivo might be attributed to its suppression of XOD activity in the liver, rather than ABCG2 in the kidney. Real-time qPCR (RT-qPCR) and Western blot analysis also confirmed the key roles of the hub genes in CP against HUA. In conclusion, CP exhibited therapeutic effect against HUA via multi-compounds, multi-targets, and multi-pathways. It possessed anti-HUA and nephroprotective effects via suppressing XOD activity, and reversed the progression of renal injury by exerting anti-inflammatory and anti-apoptotic effects.

Orthopaedic Management of Gout

Gout is characterized by the deposition of monosodium urate crystals in patients with chronically elevated blood levels of uric acid. It is the most common form of inflammatory arthritis in the United States and is often comorbid with hypertension, obesity, and chronic kidney disease. Initial presentation is usually an acutely warm, swollen joint, most commonly the first metatarsophalangeal joint, but a variety of locations may be affected. The main treatment for gout is medical management of acute inflammation and chronic uric acid levels, but surgical treatment may be indicated in cases of damage to the surrounding soft tissue, concomitant septic arthritis, symptomatic cartilage loss, or neurologic deficits. Based on the literature to date, gout does not seem to independently affect outcomes after total hip, knee, and ankle arthroplasty, but associated comorbidities affecting outcomes in these patients should be considered.

The role of lipid profile in the relationship between particulate matters and hyperuricemia: A prospective population study

CONTEXT

Recent studies in specific population subgroups (e.g., pregnant women) have suggested PM exposure increases the risk of hyperuricemia. However, no studies have examined this in the general population. Furthermore, the underlying mechanism through which PM impacts hyperuricemia risk is poorly understood.

OBJECTIVE

To assess the association between long-term exposure to PM and risk of hyperuricemia and whether this association is mediated by lipid profile.

METHODS

We included 5939 participants in Southwest China from the China Multi-Ethnic Cohort (baseline 2018-2019, follow-up 2020-2021). Long-term PM pollutants (PM₁, PM_2.5, PM₁₀) exposure for each individual was represented by the three-year average PM levels before the baseline survey. Hyperuricemia at follow-up was defined as the serum uric acid above 7.0 mg/dL in men and 6.0 mg/dL in women. Serum lipids were measured at baseline including total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TG). The association of PM with hyperuricemia was accessed through logistic regression. The potential mediation effects of serum lipids were evaluated through causal mediation analyses.

RESULTS

A total of 837 participants were newly diagnosed with hyperuricemia. The odds ratios of hyperuricemia associated with an interquartile range (IQR) increase in PM₁, PM_2.5, and PM₁₀ (IQR: 21.10, 25.78, 30.43 μg m^-3) were 1.72 (95% CI: 1.23, 2.39), 2.68 (95% CI: 1.59, 4.49), and 1.81 (95% CI: 1.20, 2.72), respectively. The association between PM_2.5, PM₁, and PM₁₀ on hyperuricemia was mediated by HDL-C (10%) and LDL-C (3%).

CONCLUSION

Higher particulate matter exposure was associated with higher hyperuricemia incidence. The decline in HDL-C and rise in LDL-C partially mediated this association. These findings were conducive to scientific research about the underlying mechanism of PM on hyperuricemia.

Assessing the causal relationships between gout and hypertension: a bidirectional Mendelian randomisation study with coarsened exposures

Objectives

Observational studies have demonstrated associations between gout and hypertension, but whether they are causal remains unclear. Our work aims to assess the causal relationship between gout and hypertension.

Methods

We obtained genetic information from the Taiwan Biobank, including 88,347 participants and 686,439 single-nucleotide polymorphisms (SNPs). A novel model of Mendelian randomisation (MR) with coarsened exposures was used to examine the causality between the liability of gout on hypertension and vice versa, using 4 SNPs associated with gout and 10 SNPs associated with hypertension after removal of SNPs associated with measured confounders. The binary exposure (gout/hypertension) can be considered a coarsened approximation of a latent continuous trait. The inverse-variance weighted (IVW) and polygenic risk score (PRS) methods were used to estimate effect size. The MR analysis with coarsened exposures was performed with and without adjustments for covariates.

Results

Of the 88,347 participants, 3253 (3.68%) had gout and 11,948 (13.52%) had hypertension (men, 31.9%; mean age 51.1 [SD, 11.1] years). After adjusting to measured confounders, MR analysis with coarsened exposures showed a significant positive causal effect of the liability of gout on hypertension in both the IVW method (relative risk [RR], 1.10; 95% confidence interval [CI], 1.03–1.19; p = 0.0077) and the PRS method (RR, 1.10; 95% CI, 1.02–1.19; p = 0.0092). The result of causality was the same before and after involving measured confounders. However, there was no causal effect of the liability of hypertension on gout.

Conclusions

In this study, we showed that the liability of gout has a causal effect on hypertension, but the liability of hypertension does not have a causal effect on gout. Adequate management of gout may reduce the risk of developing hypertension.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-022-02933-4.

Change of serum uric acid and progression of cardiometabolic multimorbidity among middle aged and older adults: A prospective cohort study

Background

Hyperuricemia is prevalent and associated with individual cardiometabolic diseases, highlighting the potential role of serum uric acid (SUA) in the development and progression of cardiometabolic multimorbidity (CMM, the coexistence of diabetes, heart disease, or stroke). This study aimed to examine the role of SUA change in the progression of CMM.

Methods

This prospective cohort study used data from the China Health and Retirement Longitudinal Study, included 4,820 participants aged 45 years or above with three complete surveys at 2011 (baseline), 2015, and 2018. SUA level at survey 2011 and 2015 was used to measure SUA change as keeping or rising to hyperuricemia, and keeping or declining to non-hyperuricemia. CMM progression was defined as the first report of CMM or additional report of cardiometabolic diseases during survey 2015 and 2018. We used logistic regression models to estimate the odds ratios (ORs) and 95% confidence intervals (95% CIs) of SUA change on CMM progression.

Results

During the follow-up of around 7 years, 519 (10.8%) of the participants kept or rose to hyperuricemia from survey 2011 to 2015, and 311 (6.5%) experienced CMM progression from survey 2015 to 2018. Participants who kept or rose to hyperuricemia had 1.86 (95% CI, 1.29, 2.68) increased odds of CMM progression compared with those who kept or declined to non-hyperuricemia. Specifically, keeping or rising to hyperuricemia (vs. keeping or declining to non-hyperuricemia) was associated with 2.01 times higher odds (95% CI, 1.18, 3.43) of incident diabetes and 1.67 times higher odds (OR:1.67; 95% CI, 1.15, 2.43) of incident cardiovascular diseases following diabetes.

Conclusion

Keeping or rising to hyperuricemia was associated with CMM progression, particularly with incident cardiovascular diseases following diabetes. These findings suggest that monitoring SUA change may provide innovative insights into the prevention of CMM, especially in the secondary prevention of CMM (i.e., preventing further progression to cardiovascular diseases among patients with diabetes).

Formulation and Evaluation of a Drug-in-Adhesive Patch for Transdermal Delivery of Colchicine

Gout is one of the most prevalent rheumatic diseases, globally. Colchicine (COL) is the first-line drug used for the treatment of acute gout. However, the oral administration of COL is restricted, owing to serious adverse reactions. Therefore, this study aimed to develop a drug-in-adhesive (DIA) patch to achieve transdermal delivery of COL. We investigated the solubility of COL in different pressure-sensitive adhesives (PSAs) using slide crystallization studies. The COL-DIA patches were optimized based on in vitro skin penetration studies and evaluated by in vivo pharmacokinetics and pharmacodynamics. The results showed that the optimized COL-DIA patch contained 10% COL, Duro-Tak 87-2516 as PSA, 5% oleic acid (OA) and 5% propylene glycol (PG) as permeation enhancer, exhibiting the highest in vitro cumulative penetration amount of COL (235.14 ± 14.47 μg∙cm^-2 over 48 h). Pharmacokinetic studies demonstrated that the maximum plasma drug concentration (C_max) was 2.65 ± 0.26 ng/L and the mean retention time (MRT) was 37.47 ± 7.64 h of the COL-DIA patch, effectively reducing the drug side effects and prolonging drug activity. In addition, pharmacodynamic studies showed the patch significantly decreased the expression levels of inflammatory factors of gouty rats and reduced pathological damage in the ankle joint of rats, making it an attractive alternative to the administration of COL for the treatment of gout.

Medicinal fungus Phellinus igniarius alleviates gout in vitro by modulating TLR4/NF-kB/NLRP3 signaling

Background:Phellinus igniarius (P. igniarius) is a valuable medicinal and edible fungus with various biological activities such as anti-inflammation, antioxidation, and immune regulation. In this study, we explored the effects of P. igniarius on a gout model in vitro.

Methods: The DPPH, ABTS, and FRAP methods were combined to determine and compare the antioxidant activities of wild P. igniarius total polyphenols (WPP) and cultivated P. igniarius total polyphenols (CPP) in vitro. Spectrophotometry was used to compare the inhibitory effect of WPP and CPP on xanthine oxidase (XO) activity to evaluate anti-hyperuricemia activity in vitro. HUVECs were stimulated with monosodium urate (MSU) crystals for 24 h to establish an acute gouty inflammation model in vitro. The protective effects were compared by measuring cell viability; the contents of ICAM-1, IL-1β, IL-6 and VCAM-1; the protein expressions of TLR4 and NLRP3; reactive oxygen species production; and the nuclear translocation of NF-κB p65. UHPLC-QE-MS technology was used to explore the potential metabolic mechanism of P. igniarius against gout.

Results: WPP and CPP had strong antioxidant capacity, and the antioxidant capacity of CPP was similar to that of WPP. In a comparative experiment of xanthine oxidase activity inhibition by WPP and CPP, the IC₅₀ values were 88.19 μg/ml and 108.0 μg/ml, respectively. At a dose of 40 μg/ml, WPP and CPP significantly improved the decrease in cell viability induced by monosodium urate (150 μg/ml) and inhibited the increase in inflammatory factors such as ICAM-1, IL-1β, IL-6, and VCAM-1. The increase in TLR4 and NLRP3 protein expression induced by MSU crystals in HUVECs was also significantly inhibited by total polyphenols from wild and cultivated P. igniarius. In addition, both significantly improved MSU-induced ROS overproduction and NF-κB p65 nuclear translocation. WPP and CPP may primarily be involved in phenylalanine metabolism and lysophosphatidylcholine metabolism in their role in the treatment of gout.

Conclusion: CPP and WPP both showed good antioxidant activity and xanthine oxidase inhibitory activity and had good therapeutic effects on the gout model in vitro. Furthermore, this study indicated that cultivated P. igniarius had a protective effect similar to that of wild P. igniarius, which would be expected to improve the shortage of wild P. igniarius and promote the development of the cultivated P. igniarius industry and product development.

The NLR family pyrin domain containing 3 inflammasome in the mechanism of electroacupuncture: Current status and future perspectives

Electroacupuncture, which is the most widely used alternative medicine treatment, has been gradually recognized for its effectiveness; however, its mechanism of action is not fully understood. The NLR family pyrin domain containing 3 (NLRP3) inflammasome is a thoroughly studied inflammasome that is closely associated with Alzheimer’s disease, spinal cord injury, and other diseases and plays an important role in the diagnosis and treatment of human immune system diseases. In recent years, some scholars have found that the NLRP3 inflammasome is a part of the mechanism of action of electroacupuncture, which has attracted further attention. In the current review, using “electroacupuncture” and “NLRP3 inflammasome” as keywords and based on the existing randomized controlled trials or clinical trials, we summarize the mechanisms of electroacupuncture targeting NLRP3 inflammasome in the treatment of different diseases and discuss how to optimize the electroacupuncture protocol to obtain thorough mechanisms of NLRP3 inflammasome in electroacupuncture and improve the level of evidence.

Neutrophil extracellular traps in systemic autoimmune and autoinflammatory diseases

Systemic autoimmune diseases are characterized by the failure of the immune system to differentiate self from non-self. These conditions are associated with significant morbidity and mortality, and they can affect many organs and systems, having significant clinical heterogeneity. Recent discoveries have highlighted that neutrophils, and in particular the neutrophil extracellular traps that they can release upon activation, can have central roles in the initiation and perpetuation of systemic autoimmune disorders and orchestrate complex inflammatory responses that lead to organ damage. Dysregulation of neutrophil cell death can lead to the modification of autoantigens and their presentation to the adaptive immune system. Furthermore, subsets of neutrophils that seem to be more prevalent in patients with systemic autoimmune disorders can promote vascular damage and increased oxidative stress. With the emergence of new technologies allowing for improved assessments of neutrophils, the complexity of neutrophil biology and its dysregulation is now starting to be understood. In this Review, we provide an overview of the roles of neutrophils in systemic autoimmune and autoinflammatory diseases and address putative therapeutic targets that may be explored based on this new knowledge.

Microbiota as a new pathogenetic factor in the development of chronic hyperuricemia and gout. Part I: the current state of the problem

The gut microbiota plays a key role in metabolism and immune regulation, and imbalance in microbial composition can contribute to various diseases. We present up-to-date data on the role of the gut microbiota in the occurrence of chronic hyperuricemia (HU) and gout, which is associated with the influence of the microbiota on the synthesis of purine-metabolizing enzymes and pro-inflammatory cytokines. It has been shown that the gut microbiota plays an important role in the pathophysiology of gout and can serve as a new target for therapy. Currently, the microbial index of gout is considered as a potential method for early diagnosis of the disease, possibly already at the preclinical stage. The gut microbiota can be a starting point in the study of the pathogenesis of HU and gout. This makes it necessary to assess the pathogenetic relationship between individual specific microorganisms, the microbiota as a whole, and the development of uric acid (UA) metabolism disorders that contribute to the onset of HU and its transformation into gout. It is assumed that this approach will provide a more complete understanding of the gut microbiota participation in the synthesis of UA and its extrarenal excretion, as well as of bacteria and bacterial enzymes that can be used as a probiotic coadjuvant for the treatment and prevention of gout.

M378 exhibits anti-inflammatory activities through NLRP3 signaling pathway

Nonsteroidal anti-inflammatory drugs (NSAIDs) are frequently used drugs due to their values in attenuating pain, fever and inflammation. Unfortunately, conspicuous adverse effects, such as gastrointestinal (GI) damage and/or cardiovascular events have impeded their application in clinic. M378 is a novel hydrogen sulfide-releasing NSAIDs with uncompromised potency and negligible toxicity compared to the existing NSAIDs. However, its anti-inflammatory activity and mechanism are still an enigma. Here we investigated the effect of M378 on the NLRP3 inflammasome signaling pathway and addressed the underlying molecular mechanism. Our data in vitro showed that M378 dose-dependently inhibited the cleavage of Caspase-1 and the secretion of active IL-1β and blocked NLRP3-dependent pyroptosis in LPS-primed J774A.1 macrophages. Furthermore, M378 remarkably inhibited upstream ASC oligomerization and ROS production regarding the process of NLRP3 inflammasome assembly. Our data in vivo demonstrated that M378 protected mice from acute liver injury, reducing the levels of ALT/AST and IL-1β and improving hepatic pathological damages. Immunoblot analysis revealed that M378 inhibited the expressions of Caspase-1 and IL-1β in liver tissues of ALI mice. We also showed that M378 alleviated IL-1β secretion and peritoneal neutrophils infiltration in MSU-elicited acute peritonitis mice. In conclusion, M378 exerted its anti-inflammatory effect both in vitro and in vivo and its mechanisms are at least connected to its inhibitory performance on the generation of ASC oligomers and ROS production. These findings give an insight. into the molecular mechanism of hydrogen sulfide-releasing NSAIDs and support a potent therapeutic role of M378 in the treatment of NLRP3-driven inflammatory diseases.

Transcriptomic analysis of the anti-inflammatory effect of Cordyceps militaris extract on acute gouty arthritis

Background: Gouty arthritis (GA) is a common inflammatory disease that causes pain due to the deposition of monosodium urate (MSU) crystals into joints and surrounding tissues. Anti-inflammatory drugs have significant clinical anti-inflammatory and analgesic effects, but they have many side effects. Cordyceps militaris is an edible and medicinal fungus, and its extract (CME) has good anti-inflammatory and analgesic effects. This study aimed to investigate the anti-inflammatory effect of CME on GA and its underlying mechanism.

Methods: The effect of CME on the expression of related inflammatory factors and histopathological changes in the MSU-induced acute inflammatory gout model in rats was studied by ELISA and HE, and its anti-inflammatory mechanism was analyzed by transcriptome combined with RT-qPCR.

Results: CME significantly improved gait scores and joint swelling in GA rats, and reduced MSU-induced inflammatory cell infiltration. CME inhibited MSU-induced inflammatory responses by reducing the levels of pro-inflammatory factors TNF-α, IL-1β, IL-6, and Caspase-1 and increasing the anti-inflammatory factor IL-10. Transcriptome analysis showed that CME significantly altered inflammation-related cytokine pathways, and identified four major genes involved in regulation of inflammation, CCL7, CSF2RB, LIF, and IL-1β. In addition, RT-qPCR was performed to verify these differential genes.

Conclusion: CME significantly alleviated the inflammatory progression of GA and ameliorated the onset of GA. The underlying mechanism may be related to triggering the cytokine-cytokine receptor interaction signaling pathway to inhibit the activation of the inflammasome and regulate the immune system. And it regulates the inflammatory response induced by MSU crystals through the genes CCL7, CSF2RB, and IL-1β.

Treatment of Gout with TCM Using Turmeric and Corn Silk: A Concise Review Article and Pharmacology Network Analysis

OBJECTIVE

This work aimed to study the compounds, targets, and pathways of turmeric and corn silk for gout and to explore the mechanism of "the same disease with different treatments" based on network pharmacology and molecular docking.

METHODS

We used the TCMSP, PubChem, and SEA databases to screen the compounds and targets of turmeric and corn silk, gout-related proteins through TTD, Drugbank, DisGeNET, GeneCards, OMIM, and PharmGkb, and used Cytoscape to construct a "compound-target-disease" network. Then, we constructed a protein-protein interaction network (PPI) and used Metascape to perform GO and KEGG analysis. Finally, molecular docking (SYBYL) was used to verify the degree of binding between key targets and compounds.

RESULTS

We found bisacumol, campesterol, and stigmasterol to be the main turmeric compounds that exerted a marked effect on gout treatment by targeting protein processing in the endoplasmic reticulum through the HSPA1B, HSP90AB1, and STUB1 proteins. The main corn silk compound, Mandenol, treated gout by targeting the Hippo signaling pathway through the CTNNB1, YWHAG, and YWHAZ proteins.

CONCLUSION

Turmeric and corn silk can treat the same disease, gout, through different pathways and targets. The scientific connotation of "same disease with different treatments" can be preliminarily clarified by analyzing targets and pathways.

Metagenomic Analysis of Gut Microbiome in Gout Patients with Different Chinese Traditional Medicine Treatments

Introduction

Changes in eating habits have made gout a metabolic disease of increasing concern. Previous studies have indicated that there are significant differences in species composition and abundance of gut microbiome in gout patients compared with average. Considering that traditional Chinese medicine has a momentous effect in treating gout, the research study aimed to explore the differences of genomic and metabolomics of gut microbiome before and after traditional Chinese medicine treatment in patients with gout.

Method

30 patients with gout and 29 matched controls were recruited of which 16 patients took H treatment and 14 patients took T treatment. Stools were collected twice for patients before and after treatment and only once for controls. A total of 89 samples were annotated with metagenomic species and functions, and the enrichment analysis of differential genes and KO pathway was carried out.

Result

The results showed a decrease in the diversity of gut microbiome in gout patients and the gene abundance and metabolomics had great differences among study groups. The number of bacterial genera also had significant differences among treatment groups. Moreover, among different groups, the regulation of different species was variously correlated. The correlation between species and clinical laboratory indicators in the rising group was stronger than that in the decreasing group and the upregulation of some strain was related to the content of urea nitrogen.

Conclusion

After the traditional Chinese medicine treatment, the glutathione pathway was significantly enriched and some pathogenic bacteria were significantly inhibited. The study suggests that traditional Chinese medicine treatment may exert its therapeutic effect by inhibiting relevant pathways.

The Good, the Bad and the New about Uric Acid in Cancer

Simple Summary

The concentration of uric acid in blood is sex-, age- and diet-dependent and is maintained close to its maximal solubility, indicating that it plays some important role. Indeed, it has been demonstrated that, at physiological concentrations, uric acid is a powerful antioxidant and is a scavenger of singlet oxygen and radicals. At high intracellular concentration, uric acid has been demonstrated to act as a pro-oxidant molecule. Recently, uric acid has been reported to affect the properties of several proteins involved in metabolic regulation and signaling, and the relationship between uric acid and cancer has been extensively investigated. In this review, we present the most recent results on the positive and negative effects played by uric acid in cancer and some new findings and hypotheses about the implication of this metabolite in the pathogenesis of several diseases such as metabolic syndrome, diabetes, and inflammation, thus favoring the development of cancer.

Abstract

Uric acid is the final product of purine catabolism in man and apes. The serum concentration of uric acid is sex-, age- and diet-dependent and is maintained close to its maximal solubility, indicating that it plays some important role. Indeed, it has been demonstrated that, at physiological concentrations, uric acid is a powerful antioxidant, while at high intracellular concentrations, it is a pro-oxidant molecule. In this review, we describe the possible causes of uric acid accumulation or depletion and some of the metabolic and regulatory pathways it may impact. Particular attention has been given to fructose, which, because of the complex correlation between carbohydrate and nucleotide metabolism, causes uric acid accumulation. We also present recent results on the positive and negative effects played by uric acid in cancer and some new findings and hypotheses about the implication of this metabolite in a variety of signaling pathways, which can play a role in the pathogenesis of diseases such as metabolic syndrome, diabetes, and inflammation, thus favoring the development of cancer. The loss of uricase in Homo sapiens and great apes, although exposing these species to the potentially adverse effects of uric acid, appears to be associated with evolutionary advantages.

Linear and non-linear Mendelian randomization analyses of sex-specific associations between sleep duration and hyperuricemia

Background

Observational studies have suggested a potential non-linear association between sleep duration and hyperuricemia. However, the causal nature and sex-specific differences are poorly understood. We aimed to determine the shape of sex-specific causal associations between sleep duration and hyperuricemia in the UK Biobank.

Methods

Logistic regression was used to investigate the observational association between self-reported sleep duration and hyperuricemia among 387,980 white British participants (mean age: 56.9 years and 46.0% males). Linear and non-linear Mendelian Randomization (MR) analyses were performed to assess the causal association between continuous sleep duration and hyperuricemia. The causal effects of genetically predicted short (<7 h) and long (>8 h) sleep durations on hyperuricemia were further estimated, respectively.

Results

Traditional observational analysis suggested U- and J-shaped associations between sleep duration and hyperuricemia in females and males, respectively. Linear MR did not support the causal effect of sleep duration on hyperuricemia. Non-linear MR demonstrated an approximately U-shaped causal association between continuous sleep duration and hyperuricemia in overall participants and females, but not in males. Genetically predicted short sleep duration was significantly associated with hyperuricemia in females (OR [95% CI]: 1.21 [1.08–1.36]; P = 0.001), but not in males (1.08 [0.98–1.18]; P = 0.137). By contrast, genetically predicted long sleep duration was not significantly associated with the risk of hyperuricemia in either females or males.

Conclusion

Genetically predicted short sleep duration is a potential causal risk factor for hyperuricemia for females but has little effect on males. Long sleep duration does not appear to be causally associated with hyperuricemia.

Biomarker-driven feedback control of synthetic biology systems for next-generation personalized medicine

Many current clinical therapies for chronic diseases involve administration of drugs using dosage and bioavailability parameters estimated for a generalized population. This standard approach carries the risk of under dosing, which may result in ineffective treatment, or overdosing, which may cause undesirable side effects. Consequently, maintaining a drug concentration in the therapeutic window often requires frequent monitoring, adversely affecting the patient’s quality of life. In contrast, endogenous biosystems have evolved finely tuned feedback control loops that govern the physiological functions of the body based on multiple input parameters. To provide personalized treatment for chronic diseases, therefore, we require synthetic systems that can similarly generate a calibrated therapeutic response. Such engineered autonomous closed-loop devices should incorporate a sensor that actively tracks and evaluates the disease severity based on one or more biomarkers, as well as components that utilize these molecular inputs to bio compute and deliver the appropriate level of therapeutic output. Here, we review recent advances in applications of the closed-loop design principle in biomedical implants for treating severe and chronic diseases, highlighting translational studies of cellular therapies. We describe the engineering principles and components of closed-loop therapeutic devices, and discuss their potential to become a key pillar of personalized medicine.

Profiling of Serum Oxylipins Identifies Distinct Spectrums and Potential Biomarkers in Young People with Very Early Onset Gout

Objective

Oxylipins modulate inflammation via complex pathways. The oxylipin profile in gout remains unexplored. In this study, we systemically profiled oxylipins in young men and identified new oxylipin biomarkers for clinical use in differentiating gout from hyperuricemia.

Methods

Oxylipin profiling was performed in 90 men (30 very early onset gout, 30 asymptomatic HU (HU) and 30 normouricemia (NU), all aged &lt;20 years) divided into discovery and validation sample sets. The dataset was analyzed based on orthogonal projection to latent structure-discriminant analysis (OPLS-DA). Correlation network and pathway enrichment were conducted to reveal potential oxylipin-involved pathways of gout. Candidate oxylipins were further evaluated and optimized in the validation cohort, and differential oxylipin biomarkers combined with or without serum urate were applied to construct diagnosis models.

Results

In discovery stage 21 differential oxylipins between the gout vs HU comparisons and 14 differential oxylipins between the gout vs NU comparisons were discovered. Correlation network analysis was performed and 14(S)-HDHA（14S-hydroxy-4Z, 7Z, 10Z, 12E, 16Z, 19Z-docosahexaenoic acid）was identified as a hub metabolite in both comparisons. Seven down-regulated oxylipins in gout vs HU group and five down-regulated oxylipins in gout vs NU group were validated. Diagnostic models were constructed with the above oxylipins, with 14(S)-HDHA alone acquiring area under the curve (AUC) 1 (95%CI, 1–1) in both comparisons.

Conclusion

Young men with very early onset gout have distinct oxylipin spectrums, especially those derived from AA (arachidonic acid), EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). Differential oxylipins could serve as candidate serum biomarkers in differentiating gout from hyperuricemia.

Lagotis brachystachya maxim attenuates chronic alcoholic liver injury combined with gouty arthritis in rats via its anti-inflammatory activity

Lagotis brachystachya Maxim, a common herb in Tibetan medicine, is mainly used to treat pneumonia, hepatitis, yellow water disease (gouty arthritis). Since long-term heavy drinking is also a risk factor for gouty arthritis, the present study aimed to evaluate the underlying protective role and mechanism of extracts of Lagotis brachystachya (ELB) in chronic alcoholic liver injury combined with gouty arthritis. The rat chronic alcoholic liver injury combined with gouty arthritis model was established by long-term alcohol consumption and monosodium urate (MSU) injection. The therapeutical action of ELB was then evaluated by biochemical measurement, histopathological examination, ankle swelling assessment, and protein detection. According to biochemical measurements and histopathological evaluation, ELB could alleviate the symptoms of alcoholic liver injury combined with gouty arthritis. In addition, chronic alcohol consumption and MSU activated inflammatory-related signaling such as TLR4/MyD88/NF-κB, NLRP3, and JAK2/STAT3 pathways in the liver and synovial tissues, while ELB significantly inhibited the activation of the inflammatory signaling pathway. In conclusion, ELB is protective in rats with chronic alcoholic liver injury and gouty arthritis, possibly mediated by the inhibition of TLR4/MyD88/NF-κB, NLRP3, and JAK2-STAT3 signaling pathways in both the hepatic and synovial tissues.

The interplay between HLA-B and NLRP3 polymorphisms may be associated with the genetic susceptibility of gout

BACKGROUND

HLA and NLRP3 play an important role in the development of various autoimmune and autoinflammatory diseases. Gout is an autoinflammatory disease associated with multiple genetic and environmental factors. The objective of the present study was to evaluate the interaction and association between genetic polymorphisms of HLA-B and the NLRP3 gene in Mexican patients with gout.

METHODS AND RESULTS

Eighty-one patients with gout were included and compared with 95 healthy subjects. The polymorphisms rs4349859, rs116488202, rs2734583 and rs3099844 (within the HLA-B region) and rs3806268 and rs10754558 of the NLRP3 gene were genotyped using TaqMan probes in a Rotor-Gene device. The interactions were determined using the multifactorial dimensionality reduction (MDR) method, while the associations were determined through logistic regression models. The MDR analysis revealed significant interactions between the rs116488202 and rs10754558 polymorphisms with an entropy value of 4.31% (p < 0.0001). Significant risk associations were observed with rs4349859 and rs116488202 polymorphisms (p < 0.01); however, no significant associations were observed with the polymorphisms of the NLRP3 gene.

CONCLUSIONS

The results suggest that HLA-B polymorphisms and their interaction with NLRP3 may contribute to the genetic susceptibility of gout.

Environmental factors and risk of gout

Gout is a chronic disease with inflammatory arthritis caused by monosodium urate (MSU) crystals deposition, an elevated serum urate level (hyperuricaemia) is the critical factor leading to MSU crystals deposition and promoting the progression of gout. The onset and development of gout is generally the result of multiple factors, such as diet, heredity and environmental factors. Although genetics and diet are thought to play as major factors, a growing body of research evidence has highlighted that environmental factors also play a significant role in the onset and exacerbation of gout. Recent studies have shown that air pollutants such as particulate matter, sulfur dioxide (SO₂) and carbon monoxide (CO) may increase the risk of hospitalizations for gout, and that the changes in temperature and humidity may affect uric acid (UA) levels. There is also seasonal trend in gout. It has been demonstrated that environmental factors may induce or accelerate the production and release of pro-inflammatory mediators, causing an unbalance oxidative stress and systemic inflammation, and then participating in the overall process or a certain link of gout. Moreover, several environmental factors have shown the ability to induce the production urate and regulate the innate immune pathways, involving in the pathogenesis of gout. Nevertheless, the role of environmental factors in the etiology of gout remains unclear. In this review, we summarized the recent literatures and aimed to discuss the relationship between environmental factors (such as microclimate, season, ambient/indoor air pollution and extreme weather) and gout. We further discussed the inflammatory mechanisms of environmental factors and gout and the comprehensive effects of environmental factors on gout. We also made a prospect of the management and treatment of gout, with special consideration to environmental factors associated with gout.

A Review of Emerging Goose Astrovirus Causing Gout

In recent years, an infection in geese caused by goose astrovirus (GAstV) has repeatedly occurred in coastal areas of China and rapidly spread to inland provinces. The infection is characterized by joint and visceral gout and is fatal. The disease has caused huge economic losses to China's goose industry. GAstV is a nonenveloped, single-stranded, positive-sense RNA virus. As it is a novel virus, there is no specific classification. Here, we review the current understanding of GAstV. The virus structure, isolation, diagnosis and detection, innate immune regulation, and transmission route are discussed. In addition, since GAstV can cause gout in goslings, the possible role of GAstV in gout formation and uric acid metabolism is discussed. We hope that this review will inform researchers to rapidly develop effective methods to prevent and treat this disease.

Higher HEI-2015 scores are associated with lower risk of gout and hyperuricemia: Results from the national health and nutrition examination survey 2007-2016

Gout, the most prevalent inflammatory arthritis, is becoming increasingly prevalent in the United States and across the world, and it adversely impacts people’s quality of life and their health. Few studies have focused on the relationship between daily dietary quality and gout, so the topic requires further exploration. Data were derived from the National Health and Nutrition Examination Survey 2007–2016, and the inclusion criteria of the analytic sample were (1) adults, age ≥20 years, with complete information about HEI-2015, gout, and uric acid; (2) complete information of demographics, lifestyle (BMI, smoking, drinking), and disease history [hypertension, chronic kidney disease (CKD), diabetes]. The quality of the daily diet was reflected using the Healthy Eating Index 2015 (HEI-2015). The baseline features of different groups were examined using the Scott-Rao chi-square tests, and the association between the HEI-2015 score and the risk of gout/hyperuricemia (HUA) was investigated using weighted logistic regression models. The effects of different dietary components in the HEI-2015 on reducing the risk of gout/HUA were evaluated by weighted quantile sum (WQS) regression models. After adjusting for demographic characteristics, behavioral covariates, and disease history, higher HEI-2015 scores were associated with a significantly lower risk of gout (OR: 0.878, 95% CI: 0.876–0.880) and HUA (OR: 0.978, 95% CI: 0.976–0.979) in weighted logistic regression. Dairy, whole grains, plant proteins, and added sugar contributed greatly in HEI-2015 to reducing gout risk (weights of WQS index: 42, 17.18, 16.13, and 7.93%, respectively). Dairy, total fruits, greens and beans, and plant proteins contributed greatly in HEI-2015 to reducing HUA risk (weights of WQS index: 28.9, 17.13, 16.84, and 11.39%, respectively). As the result, adherence to the American Dietary Guidelines may assist to decrease the risk of gout/HUA in American adults, and greater emphasis should be placed on dairy products, whole grains, fruits, legumes, and added sugars.

Sacha Inchi Oil Press-Cake Protein Hydrolysates Exhibit Anti-Hyperuricemic Activity via Attenuating Renal Damage and Regulating Gut Microbiota

The incidence of hyperuricemia has increased globally due to changes in dietary habits. The sacha inchi oil press-cake is generally discarded, resulting in the waste of resources and adverse environmental impact. For the purpose of developing sacha inchi oil press-cake and identifying natural components with anti-hyperuricemic activities, we systemically investigated the underlying mechanisms of sacha inchi oil press-cake protein hydrolysates (SISH) in the hyperuricemic rat model. SISH was obtained from sacha inchi oil press-cake proteins after trypsin treatment, and 24 peptides with small molecular weight (<1000 Da) were identified. The results of animal experiments showed that SISH significantly decreased the serum uric acid (UA) level by inhibiting the xanthine oxidase (XOD) activity and regulating the gene expression related to UA production and catabolism in hyperuricemia rats, such as Xdh and Hsh. In addition, SISH attenuated the renal damage and reduced the gene expression related to inflammation (Tlr4, Map3k8, Pik3cg, Pik3ap1, Ikbke, and Nlrp3), especially Tlr4, which has been considered a receptor of UA. Notably, SISH reversed high purine-induced gut microbiota dysbiosis, particularly by enhancing the relative abundance of butyric acid-producing bacteria (unidentified_Ruminococcaceae, Oscillibacter, Ruminiclostridium, Intestinimonas). This research provided new insights into the treatment of hyperuricemia.