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.

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.

Coffee intake reduced gout risk by decreasing urate and urea while increasing SHBG levels in plasma: a mediation Mendelian randomization study.

OBJECTIVE: This study aims to investigate the causal relationships between specific dietary habits and the risk of gout, while identifying the mediators involved in these associations. METHODS: We initially assessed the causal effects of five dietary habits on gout by two-sample Mendelian randomization (MR). Subsequently, we identified mediators from five plasma metabolites by two-step MR, including urate, urea, sex hormone-binding globulin (SHBG), interleukin-18 (IL-18), and C-reactive protein (CRP). Next, we quantified the proportion of mediation effects by multivariable Mendelian randomization (MVMR). Last, we performed reverse MR analyses. Sensitivity analyses were conducted to enhance the robustness of our findings. RESULTS: Only coffee intake demonstrated a significant negative casual effect on gout (inverse variance weighted: OR = 0.444, p = 0.049). In two-step MR, coffee intake decreased urate and urea while increased SHBG levels, but did not affect IL-18 and CRP levels. Besides, urate and urea showed positive causal effects while SHBG exhibited a negative impact on gout. In mediation analysis, urate, urea, and SHBG respectively mediated 53.60%, 16.43%, and 4.81% of the total causal effect of coffee intake on gout. The three mediators collectively mediated 27.45% of the total effect. Reverse MR analyses suggested no significant reverse causal effects. Sensitivity analyses supported the reliability of our causal inferences. CONCLUSION: Coffee intake reduced gout risk by decreasing urate and urea while increasing SHBG levels in plasma. These findings accentuate the benefits of coffee intake for gout management. The mediators may provide a novel insight into potential therapeutic targets for gout prevention. Key Points • This study determines the causally protective effect of coffee intake on gout. • We reveal that coffee intake reduced the risk of gout by decreasing urate and urea while increasing SHBG levels in plasma. • Identifying specific mediators in the causal pathway from coffee intake to gout provides valuable information for clinical interventions of gout.

Data mining-guided alleviation of hyperuricemia by Paeonia veitchii Lynch through inhibition of xanthine oxidase and regulation of renal urate transporters.

BACKGROUND: Hyperuricemia (HUA) is a metabolic disease characterized by a high level of uric acid (UA). The extensive historical application of traditional Chinese medicine (TCM) offers a range of herbs and prescriptions used for the treatment of HUA-related disorders. However, the core herbs in the prescriptions and their mechanisms have not been sufficiently explained. PURPOSE: Our current investigation aimed to estimate the anti-HUA effect and mechanisms of Paeonia veitchii Lynch, an herb with high use frequency identified from data mining of TCM prescriptions. METHODS: Prescriptions for HUA/gout treatment were statistically analyzed through a data mining approach to determine the common nature and use frequency of their composition herbs. The chemical constituents of Paeonia veitchii extract (PVE) were analyzed by UPLC-QTOF-MS/MS, while its UA-lowering effect was further evaluated in adenosine-induced liver cells and potassium oxonate (PO) and hypoxanthine (HX)-induced HUA mice. RESULTS: A total of 225 prescriptions involving 246 herbs were sorted out. The properties, flavors and meridians of the appearing herbs were mainly cold, bitter and liver, respectively, while their efficacy was primarily concentrated on clearing heat and dispelling wind. Further usage frequency analysis yielded the top 20 most commonly used herbs, in which PVE presented significant inhibitory activity (IC50 = 131.33 µg/ml) against xanthine oxidase (XOD), and its constituents showed strong binding with XOD in a molecular docking study and further were experimentally validated through XOD enzymatic inhibition and surface plasmon resonance (SPR). PVE (50 to 200 µg/ml) dose-dependently decreased UA levels by inhibiting XOD expression and activity in BRL 3A liver cells. In HUA mice, oral administration of PVE exhibited a significant UA-lowering effect, which was attributed to the reduction of UA production by inhibiting XOD activity and expression, as well as the enhancement of UA excretion by regulating renal urate transporters (URAT1, GLUT9, OAT1 and ABCG2). Noticeably, all doses of PVE treatment did not cause any liver injury, and displayed a renal protective effect. CONCLUSIONS: Our results first comprehensively clarified the therapeutic effect and mechanisms of PVE against HUA through suppressing UA production and promoting UA excretion with hepatic and renal protection, suggesting that PVE could be a promising UA-lowering candidate with a desirable safety profile for the treatment of HUA and prevention of gout.

TCM and related active compounds in the treatment of gout: the regulation of signaling pathway and urate transporter.

Gout represents a metabolic ailment resulting from the accumulation of monosodium urate crystals within joints, causing both inflammation and, harm to tissues. The primary contributor to gout's emergence is an elevated presence of serum urate, which is under the regulation of kidney and, gut urate transporters. Mitigating this risk factor is crucial for averting gout's onset. Several treatments rooted in TCM and related active compounds have demonstrated efficacy in managing gout, skillfully regulating serum uric acid (UA) levels and curbing inflammation's progression. This analysis compiles key foundational research concerning the molecular signaling pathways and UA transporters linked to gout, under the regulation of TCM. The focus includes individual botanical drug, active compounds, and TCM formulations, which have been consolidated and examined in this overview. The primary keywords chosen were "gout, hyperuricemia, gouty arthritis, traditional Chinese medicine, Chinese botanical drug, medicinal botanical drug, and natural plant". Various relevant literature published within the last 5 years were gathered from electronic databases, including PubMed, Web of Science, CNKI, and others. The findings revealed that TCM has the capacity to modulate various signaling pathways, including MAPK, NF-κB, PI3K/Akt, NLRP3 and JAK/STAT. Additionally, it impacts UA transporters like URAT1, GLUT9, ABCG2, as well as OATs and OCTs, thereby contributing to gout treatment. TCM helps maintain a balanced inflammatory interaction and facilitates UA excretion. This study enhances our understanding of TCM's anti-gout mechanisms and introduces novel perspectives for establishing the clinical significance and future prospects of TCM-based gout treatment.

Causality between urate levels with sarcopenia-related traits: a bi-directional Mendelian randomization study.

Background: Observational studies have suggested associations between serum urate levels and sarcopenia, but the causality underlying this correlation remains uncertain. The principal objective of this study is to investigate a causal relationship of serum urate levels with sarcopenia-related traits (hand grip strength, lean mass, walking pace) using bidirectional two-sample Mendelian randomization (MR) approach. The utilization of MR methodology serves to minimize bias caused by reverse causality and confounding factors from observational studies. Methods: The summary statistics of serum urate levels were derived from a cohort consisting of 288,659 individuals participating in CKDGen study. The parameters of right-hand grip strength (N=461,089), left-hand grip strength (N=461,026), appendicular lean mass (ALM) (N=450,243), whole-body lean mass(N=454,850),right-leg fat-free mass(FFM;N=454,835),left-leg FFM(N=454,805), right-arm FFM(N=454,753),left-arm FFM(N=454,672) and walking pace (N=459,915)were sourced from the UK Biobank. MR analysis was conducted utilizing inverse variance weighted (IVW), weighted median, and MR-Egger to evaluate causality. Sensitivity analysis was performed using Cochran's Q test, MR-Egger intercept test, leave-one-out analysis and the funnel plot. Results: IVW estimates demonstrated that serum urate levels exhibited no causal association with sarcopenia-related traits. In the inverse MR investigation, we had exclusively discerned an inverse correlation between walking pace and serum urate levels. No compelling evidence had surfaced to substantiate any association of other sarcopenia-related traits with serum urate. Supplemental MR methods consistently validated the findings obtained from the primary analysis. Sensitivity analysis demonstrated the robustness of findings. Conclusion: Our MR study revealed the absence of the bidirectional causal relationship between serum urate levels and sarcopenia. It is imperative to acknowledge that advanced age and an individual's health status are pivotal determinants influencing urate level and the initiation and advancement of sarcopenia. However, it is worth underscoring that these aspects remain unexamined within the purview of this study. Thus, future investigations should delve deeper into these intricate facets.

Serum uric acid and risk of diabetic neuropathy: a genetic correlation and mendelian randomization study.

Background: Previous observational studies have indicated an association between serum uric acid (SUA) and diabetic neuropathy (DN), but confounding factors and reverse causality have left the causality of this relationship uncertain. Methods: Univariate Mendelian randomization (MR), multivariate MR and linkage disequilibrium score (LDSC) regression analysis were utilized to assess the causal link between SUA and DN. Summary-level data for SUA were drawn from the CKDGen consortium, comprising 288,648 individuals, while DN data were obtained from the FinnGen consortium, with 2,843 cases and 271,817 controls. Causal effects were estimated primarily using inverse variance weighted (IVW) analysis, supplemented by four validation methods, with additional sensitivity analyses to evaluate pleiotropy, heterogeneity, and result robustness. Results: The LDSC analysis revealed a significant genetic correlation between SUA and DN (genetic correlation = 0.293, P = 2.60 × 10-5). The primary methodology IVW indicated that each increase of 1 mg/dL in SUA would increase DN risk by 17% (OR = 1.17, 95% CI 1.02-1.34, P = 0.02), while no causal relationship was found in reverse analysis (OR = 1.00, 95% CI 0.98~1.01, P = 0.97). Multivariate MR further identified that the partial effect of SUA on DN may be mediated by physical activity, low density lipoprotein cholesterol (LDL-C), insulin resistance (IR), and alcohol use. Conclusion: The study establishes a causal link between elevated SUA levels and an increased risk of DN, with no evidence for a reverse association. This underscores the need for a comprehensive strategy in DN management, integrating urate-lowering interventions with modulations of the aforementioned mediators.

Paeonia × suffruticosa Andrews leaf extract and its main component apigenin 7-O-glucoside ameliorate hyperuricemia by inhibiting xanthine oxidase activity and regulating renal urate transporters.

BACKGROUND: Hyperuricemia is an important pathological basis of gout and a distinct hazard factor for metabolic syndromes and cardiovascular and chronic renal disease, but lacks safe and effective treatments currently. Paeonia × suffruticosa Andrews leaf effectively reduced serum uric acid in gout patients; however, the material foundation and the mechanism remain unclear. PURPOSE: To determine the primary active components and mechanism of P. suffruticosa leaf in hyperuricemic mice. METHODS: The chemical constituents of P. suffruticosa leaf was identified using high-performance liquid chromatographic analysis. The anti-hyperuricemic activity of P. suffruticosa leaf extract (12.5, 25, 50, 100, and 200 mg/kg) and its components was evaluated in hyperuricemic mice induced by a high purine diet for 14 days. Then, the urate-lowering effects of apigenin 7-O-glucoside (0.09, 0.18, and 0.36 mg/kg) were assessed in another hyperuricemic mice model built by administrating potassium oxonate and adenine for 4 weeks. The inhibitory effect of apigenin 7-O-glucoside on uric acid production was elucidated by investigating xanthine oxidase activity in vitro and in serum and the liver and through molecular docking. Immunofluorescence and western blot analyses of the expression of renal urate transporter 1 (URAT1), glucose transporter 9 (GLUT9), organic anion transporters 1 (OAT1), and ATP-binding cassette G member 2 (ABCG2) proteins elucidated how apigenin 7-O-glucoside promoted uric acid excretion. RESULTS: Six compounds were identified in P. suffruticosa leaf: gallic acid, methyl gallate, oxypaeoniflorin, paeoniflorin, galloylpaeoniflorin, and apigenin 7-O-glucoside. P. suffruticosa leaf extract significantly attenuated increased serum uric acid, creatinine, and xanthine oxidase activity in hyperuricemic mice. Apigenin 7-O-glucoside from P. suffruticosa leaf reduced uric acid, creatinine, and malondialdehyde serum levels, increased superoxide dismutase activity, and partially restored the spleen coefficient in hyperuricemic mice. Apigenin 7-O-glucoside inhibited xanthine oxidase activity in vitro and decreased serum and liver xanthine oxidase activity and liver xanthine oxidase protein expression in hyperuricemic mice. Molecular docking revealed that apigenin 7-O-glucoside bound to xanthine oxidase. Apigenin 7-O-glucoside facilitated uric acid excretion by modulating the renal urate transporters URAT1, GLUT9, OAT1, and ABCG2. Apigenin 7-O-glucoside protected against renal damage and oxidative stress caused by hyperuricemia by reducing serum creatinine, blood urea nitrogen, malondialdehyde, and renal reactive oxygen species levels; increasing serum and renal superoxide dismutase activity; restoring the renal coefficient; and reducing renal pathological injury. CONCLUSION: Apigenin 7-O-glucoside is the main urate-lowering active component of P. suffruticosa leaf extract in the hyperuricemic mice. It suppressed liver xanthine oxidase activity to decrease uric acid synthesis and modulated renal urate transporters to stimulate uric acid excretion, alleviating kidney damage caused by hyperuricemia.

Tailored hydrogel composite membrane for the regulated crystallization of monosodium urate monohydrate within coffee's metabolites system.

Herein, a facile bionic research platform with fabricated hydrogel composite membrane (HCM) is constructed to uncover the effects of the main components of coffee's metabolites on MSUM crystallization. Tailored and biosafety polyethylene glycol diacrylate/N-isopropyl acrylamide (PEGDA/NIPAM) HCM allows the proper mass transfer of coffee's metabolites and can well simulate the process of coffee's metabolites acting in the joint system. With the validations of this platform, it is shown that chlorogenic acid (CGA) can hinder the MSUM crystals formation from 45 h (control group) to 122 h (2 mM CGA), which is the most likely reason that reduces the risk of gout after long-term coffee consumption. Molecular dynamics simulation further indicates that the high interaction energy (Eint) between CGA and MSUM crystal surface and the high electronegativity of CGA both contribute to the restraint of MSUM crystal formation. In conclusion, the fabricated HCM, as the core functional materials of the research platform, presents the understanding of the interaction between coffee consumption and gout control.

Renal herb formula protects against hyperuricemic nephropathy by inhibiting apoptosis and inflammation.

BACKGROUND: Hyperuricemic nephropathy may be induced by the elevation and accumulation of uric acid in kidney after hyperuricemia, which leads to kidney residential cells apoptosis and inflammation. Renal herb formula (RHF) is a self-designed formula based on traditional Chinese medicine theory and clinical practice in kidney disease treatment. In the literature available currently, there is not yet research article reporting the reno-protective effect of RHF against hyperuricemic nephropathy. PURPOSE: This study was performed to analyze the bioactive compound profiles of RHF, evaluate its protective effects against hyperuricemic nephropathy, and investigate the mechanisms of actions regarding apoptosis and inflammation. METHODS: Ultra-performance liquid chromatography with a diode-array detector was applied to establish fingerprint and chemical composition of RHF. Potassium oxonate was used to induce hyperuricemic nephropathy in mice, and uric acid was used to stimulate apoptosis and inflammatory response in HK-2 cells, while the mice and cells were treated with RHF to explore its reno-protective effects and mechanisms. RESULTS: It was found that chlorogenic acid, neochlorogenic acid, cryptochlorogenic acid, and isochlorogenic acid A-C may be the characteristic components of RHF. RHF treatment could improve kidney functions in mice with hyperuricemic nephropathies, such as decreasing urine protein, uric acid, and creatinine and serum uric acid, creatinine, and urea nitrogen. Histopathological observations showed that RHF treatment ameliorated kidney glomerular hypotrophy, tubular damage, and inflammatory infiltration. Mechanism studies revealed that RHF inhibited kidney residential cell apoptosis and inflammatory response by targeting the p53-associated intrinsic apoptosis pathway and NF-κB-mediated inflammatory pathway. CONCLUSION: Taken together, it could be concluded that RHF exerted reno-protective effects against hyperuricemic nephropathy through reducing apoptosis and inflammation. RHF and the bioactive compounds chlorogenic acid analogs as promising candidates may be developed into novel and effective drugs for hyperuricemic nephropathy treatment and management.

Diallyl trisulfide inhibits monosodium urate-induced NLRP3 inflammasome activation via NOX3/4-dependent mitochondrial oxidative stress in RAW 264.7 and bone marrow-derived macrophages.

BACKGROUND: Monosodium urate (MSU) crystals are associated with gouty inflammatory diseases. MSU-associated inflammation is majorly triggered by NOD-like receptor protein 3 (NLRP3) inflammasome that promotes interleukin (IL)-1ß secretion. Although diallyl trisulfide (DATS) is well-known polysulfide garlic compounds with anti-inflammatory effects, its action in MSU-induced inflammasome activation has not been known yet. PURPOSE: The objective of the current study was to investigate anti-inflammasome effects and mechanisms of DATS in RAW 264.7 and bone marrow-derived macrophages (BMDM). METHODS: The concentrations of IL-1ß were analyzed with enzyme-linked immunosorbent assay. The MSU-induced mitochondrial damage and reactive oxygen species (ROS) production were detected by fluorescence microscope and flow cytometry. The protein expressions of NLRP3 signaling molecules, NADPH oxidase (NOX) 3/4 were assessed with Western blotting. RESULTS: DATS suppressed MSU-induced IL-1ß and caspase-1 accompanied by decreased inflammasome complex formation in RAW 264.7 and BMDM. In addition, DATS restored mitochondrial damage. DATS downregulated NOX 3/4 that were upregulated by MSU as predicted by gene microarray and confirmed by Western blotting. CONCLUSION: This study first reports mechanistic finding that DATS alleviates MSU-induced NLRP3 inflammasome by mediating NOX3/4-dependent mitochondrial ROS production in macrophages in vitro and ex vivo, suggesting DATS could be effective therapeutic candidate for gouty inflammatory condition.

Nontraditional Risk Factors for Progression Through Chronic Kidney Disease Risk Categories: The Coronary Artery Risk Development in Young Adults Study.

BACKGROUND: There may be nontraditional pathways of chronic kidney disease (CKD) progression that are complementary to classical pathways. Therefore, we aimed to examine nontraditional risk factors for incident CKD and its progression. METHODS: We used the generally healthy population (n = 4382) starting at age 27-41 years in the Coronary Artery Risk Development in Young Adults (CARDIA) cohort, which is an observational longitudinal study. Nontraditional risk factors included forced vital capacity, inflammation, serum urate, and serum carotenoids. CKD risk category was classified using the estimated glomerular filtration rate (eGFR) and urinary albumin-to-creatinine ratio (UACR) measured in 1995-1996 and repeated every 5 years for 20 years: No CKD, low risk, moderate risk, high risk, and very high risk. RESULTS: At baseline, 84.8% had no CKD (eGFR ≥60 mL/min/1.73 m2 and UACR <10 mg/g), 10.3% were in the low risk (eGFR ≥60 and UACR 10-29), and 4.9% had CKD (eGFR <60 and/or UACR ≥ 30). Nontraditional risk factors were significantly associated with the progression of CKD to higher categories. Hazard ratios per standard deviation of the predictor for incident CKD and its progression from the No CKD and low and moderate risk into CKD were inverse for forced vital capacity and serum carotenoids and positive for serum urate, GlycA, and C-reactive protein, the first 3 even after adjustment for conventional risk factors. CONCLUSION: Several nontraditional markers were significantly associated with an increased risk of progression to higher CKD categories in generally healthy young to middle-aged adults.

Naringenin Ameliorates Hyperuricemia by Regulating Renal Uric Acid Excretion via the PI3K/AKT Signaling Pathway and Renal Inflammation through the NF-κB Signaling Pathway.

Hyperuricemia characterized by high serum levels of uric acid (UA, >6.8 mg/dL) is regarded as a common chronic metabolic disease. When used as a food supplement, naringenin might have various pharmacological activities, including antioxidant, free-radical-scavenging, and inflammation-suppressing activities. However, the effects of naringenin on hyperuricemia and renal inflammation and the underlying mechanisms remain to be elucidated. Here, we comprehensively examined the effects of naringenin on hyperuricemia and the attenuation of renal impairment. Mice were injected with 250 mg/kg of potassium oxonate (PO) and given 5% fructose water to induce hyperuricemia. The pharmacological effects of naringenin (10 and 50 mg/kg) and benzbromarone (positive control group, 20 mg/kg) on hyperuricemic mice were evaluated in vivo. The disordered expression of urate transporters in HK-2 cells was stimulated by 8 mg/dL UA, which was used to determine the mechanisms underlying the effects of naringenin in vitro. Naringenin markedly reduced the serum UA level in a dose-dependent manner and improved renal dysfunction. Moreover, the increased elimination of UA in urine showed that the effects of naringenin were associated with the regulation of renal excretion. Further examination indicated that naringenin reduced the expression of GLUT9 by inhibiting the PI3K/AKT signaling pathway and reinforced the expression of ABCG2 by increasing the abundance of PDZK1 in vivo and in vitro. Furthermore, sirius red staining and western blotting indicated that naringenin plays a protective role in renal injury by suppressing increases in the levels of pro-inflammatory cytokines, including IL-6 and TNF-α, which contribute to the inhibition of the TLR4/NF-κB signaling pathway in vivo and in vitro. Naringenin supplementation might be a potential therapeutic strategy to ameliorate hyperuricemia by promoting UA excretion in the kidney and attenuating the inflammatory response by decreasing the release of inflammatory cytokines. This study shows that naringenin could be used as a functional food or dietary supplement for hyperuricemia prevention and treatment.

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-1ß (IL-1ß) 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/ß (IKKα/ß), NF-κB inhibitor α (IKBα), phospho-IKKα/ß (p-IKKα/ß), NLRP3, PYCARD, and CASP1 were monitored by Western blotting. Serum IL-1ß 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-1ß and IL-18 in cell culture supernatants was measured by ELISA, and the protein expressions of TLR4, MyD88, NF-κB (p50/p65), IKKα/ß, I κBß, p-IKKα/ß, NLRP3, PYCARD, and CASP1 in macrophages were analyzed by Western blotting. RESULTS: (1) TLR4, NF-κB (p65), PYCARD, CASP1, and IL-1ß 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, IKKß, MyD88, NF-κB, p-IKKα/ß, 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-1ß protein levels were significantly higher in the AP and NAP groups than in the HC group (P<0.01). (4) The IL-1ß 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-1ß 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/ß, p-IκBα, p-IKKα/ß, 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.

New insight into the management of renal excretion and hyperuricemia: Potential therapeutic strategies with natural bioactive compounds.

Hyperuricemia is the result of increased production and/or underexcretion of uric acid. Hyperuricemia has been epidemiologically associated with multiple comorbidities, including metabolic syndrome, gout with long-term systemic inflammation, chronic kidney disease, urolithiasis, cardiovascular disease, hypertension, rheumatoid arthritis, dyslipidemia, diabetes/insulin resistance and increased oxidative stress. Dysregulation of xanthine oxidoreductase (XOD), the enzyme that catalyzes uric acid biosynthesis primarily in the liver, and urate transporters that reabsorb urate in the renal proximal tubules (URAT1, GLUT9, OAT4 and OAT10) and secrete urate (ABCG2, OAT1, OAT3, NPT1, and NPT4) in the renal tubules and intestine, is a major cause of hyperuricemia, along with variations in the genes encoding these proteins. The first-line therapeutic drugs used to lower serum uric acid levels include XOD inhibitors that limit uric acid biosynthesis and uricosurics that decrease urate reabsorption in the renal proximal tubules and increase urate excretion into the urine and intestine via urate transporters. However, long-term use of high doses of these drugs induces acute kidney disease, chronic kidney disease and liver toxicity. Therefore, there is an urgent need for new nephroprotective drugs with improved safety profiles and tolerance. The current systematic review summarizes the characteristics of major urate transporters, the mechanisms underlying the pathogenesis of hyperuricemia, and the regulation of uric acid biosynthesis and transport. Most importantly, this review highlights the potential mechanisms of action of some naturally occurring bioactive compounds with antihyperuricemic and nephroprotective potential isolated from various medicinal plants.

Feasibility of conducting a randomized, placebo-controlled study assessing whether omega-3 fatty acids prevent gout flares when starting urate-lowering treatment.

Objective: The aim was to test the feasibility of a randomized controlled trial exploring whether omega-3 fatty acid supplementation limits gout flares during treat-to-target urate-lowering treatment (T2T-ULT). Methods: Adults with at least one gout flare in the past 12 months and serum urate (SU) ≥360 µmol/l were recruited from general practices (primary method) and randomly assigned 1:1 to receive omega-3 fatty acid supplementation (4 g/day) or placebo for 28 weeks. At week 5, participants began T2T-ULT. The primary outcome was drop-out rate. Secondary outcomes were recruitment rate, outcome data completeness, the number, severity and duration of gout flares between weeks 5 and 28, and study drug compliance. Results: Ninety-five per cent of randomized participants (n = 60) completed all study visits. The primary method recruitment rate was 2.2%. Fifty and 42 participants achieved SU < 360 and 300 µmol/l (6 and 5 mg/dl), respectively. The number of gout flares [median (interquartile range): active 1 (0-2) and placebo 1 (0-2)], flare duration [mean (s.d.): active 7.00 (4.52) days and placebo 7.06 (8.14) days] and time to first flare [hazard ratio (95% CI) 0.97 (0.50, 1.86)] were comparable between both arms. Study drug compliance was high and comparable in both arms [median (interquartile range) returned capsule count: active 57 (26-100) and placebo 58 (27-154)]; red blood cell omega-3 fatty acid index increased twofold in the active arm and remained unchanged in the control arm. Conclusion: The study demonstrated feasibility and provided useful metrics for conducting a community-based gout flare prophylaxis trial. Study registration: ISRCTN; https://www.isrctn.com/; ISRCTN79392964.

Bactericidal/Permeability-Increasing Protein Downregulates the Inflammatory Response in In Vivo Models of Arthritis.

We investigated the effects of bactericidal/permeability-increasing protein (BPI) alone or in combination with hyaluronic acid (HA) in two animal models: collagen-induced arthritis (CIA) and crystal-induced inflammation. In CIA, mice were intraperitoneally injected with PBS, HA, or BPI plus or minus HA, twice a week for 2 months, and then euthanized to collect paw and blood. Arthritis was assessed in ankle joints by clinical and histological evaluation. Pathogenic crystals were intraperitoneally injected in mice plus or minus BPI, or with a composition of BPI and HA. After sacrifice, total and differential leukocyte counts were determined. Cytokine levels were measured in serum and peritoneal fluids. In CIA mice, BPI improved clinical and histological outcomes (histological scores ≥2-fold), and downregulated inflammatory mediators (47-93%). In crystal-induced inflammation, BPI reduced leukocyte infiltration (total count: ≥60%; polymorphonuclear cells: ≥36%) and inhibited cytokine production (35-74%). In both models, when mice were co-treated with BPI and HA, the improvement of all parameters was greater than that observed after administration of the two substances alone. Results show that BPI attenuates CIA and inflammation in mice, and this effect is enhanced by HA co-administration. Combined use of BPI and HA represents an interesting perspective for new potential treatments in arthritis.

Probiotic effects of Lacticaseibacillus rhamnosus 1155 and Limosilactobacillus fermentum 2644 on hyperuricemic rats.

Hyperuricemia is the main cause of gout and involved in the occurrence of multiple diseases, such as hypertension, metabolic disorders and chronic kidney disease. Emerging evidence suggests that lactic acid bacteria (LAB) have shown the beneficial effects on the prevention or treatment of hyperuricemia. In this study, the urate-lowering effect of two LAB strains, Lacticaseibacillus rhamnosus 1155 (LR1155) and Limosilactobacillus fermentum 2644 (LF2644) on hyperuricemic rats were investigated. A hyperuricemic rat model was induced by the intragastric treatment of potassium oxonate, combined with a high purine diet. The oral administration of LR1155, LF2644, or a combination of LR1155 and LF2644 for 4 weeks significantly prevented the rise of the serum uric acid (UA) induced by hyperuricemia. LR1155 and LF2644 significantly elevated the fecal UA levels, increased the UA content and up-regulated gene expression of UA transporter, ATP-binding cassette subfamily G-2 (ABCG2), in colon and jejunum tissues, suggesting the accelerated UA excretion from the intestine. Besides, LR1155 significantly inhibited the activity of xanthine oxidase (XOD) in liver and serum, benefited the reduce of UA production. In addition, LF2644 strengthened the gut barrier functions through an up-regulation of the gene expressions for occluding and mucin2, accompanied with the reduced inflammatory indicators of lipopolysaccharide (LPS) and interleukin-1ß (IL-1ß) in hyperuricemic rat. Moreover, using 16s rDNA high-throughput sequencing of feces, LR1155 was shown to improve the hyperuricemia induced gut microbial dysbiosis. The genera Roseburia, Butyricicoccus, Prevotella, Oscillibacter, and Bifidobacterium may associate with the effect of LR1155 on microbiota in hyperuricemic rats. Collectively, the results indicated that LR1155 and LF2644 exhibit urate-lowering effects and could be used alone or in combination as a new adjuvant treatment for hyperuricemia.

Extract of Aster glehni ameliorates potassium oxonate-induced hyperuricemia by modulating renal urate transporters and renal inflammation by suppressing TLR4/MyD88 signaling.

Recent studies suggest that Aster glehni extract (AGE) reduces hyperuricemia by preventing xanthine oxidase activity. However, its effect on renal urate transporters responsible for modulating urate excretion has not been examined. This study investigated whether AGE affects gene expressions of urate transporters using potassium oxonate (PO)-induced hyperuricemia rats. Furthermore, the underlying mechanisms of AGE were explored to ameliorate renal inflammation and injury by PO. AGE effectively restored PO-induced dysregulation of renal urate transporter 1 (URAT1), glucose transporter 9 (GLUT9), ATP-binding cassette transporter subfamily G member 2 (ABCG2), organic anion transporter 1 (OAT1), and organic cation transporter 1 (OCT1), resulting in increasing urate excretion. Additionally, AGE suppressed toll-like receptor 4/myeloid differentiation factor 88 (TLR4/MyD88) signaling, phosphorylation of nuclear factor kappa B (NF-κB), and renal production of IFN-γ, IL-1ß, TNF-α, and IL-6. These results suggest that AGE may ameliorate PO-induced hyperuricemia by modulating renal transporters, and further renal inflammation via inhibiting the TLR4/MyD88/NF-κB signaling pathway. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-022-01153-5.

Inosine in Neurodegenerative Diseases: From the Bench to the Bedside.

Neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and multiple sclerosis (MS), currently represent major unmet medical needs. Therefore, novel therapeutic strategies are needed in order to improve patients' quality of life and prognosis. Since oxidative stress can be strongly involved in neurodegenerative diseases, the potential use of inosine, known for its antioxidant properties, in this context deserves particular attention. The protective action of inosine treatment could be mediated by its metabolite urate. Here, we review the current preclinical and clinical studies investigating the use of inosine in AD, PD, ALS, and MS. The most important properties of inosine seem to be its antioxidant action and its ability to raise urate levels and to increase energetic resources by improving ATP availability. Inosine appears to be generally safe and well tolerated; however, the possible formation of kidney stones should be monitored, and data on its effectiveness should be further explored since, so far, they have been controversial. Overall, inosine could be a promising potential strategy in the management of neurodegenerative diseases, and additional studies are needed in order to further investigate its safety and efficacy and its use as a complementary therapy along with other approved drugs.